36th Annual Conference of the South African Association of ......A new student council member for the 2010/2011 period will be elected ... Danie Huyser Sarel Cilliers Anine Jordaan

POTCHEFSTROOM CAMPUS

Applications of plant science: from natural to human environments

36th Annual Conference of the South African Association of Botanists (SAAB)

North-West University, Potchefstroom Monday 11 – Friday 15 January 2010

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Welcome to SAAB 2010

We welcome you to the 36th annual SAAB congress at the Potchefstroom Campus of

the North-West University. The congress will be officially opened by Prof. Kobus

Pienaar, the Dean of the Faculty of Natural Sciences, North-West University. An

official word of welcome will be extended by Prof. Jill Farrant, President of SAAB.

TABLE OF CONTENTS

GENERAL INFORMATION __________________________________________2

Congress Programme_____________________________________________________ 2

Congress Workshop ______________________________________________________ 2

Congress Excursion (1 day excursion to the Vredefort Dome) ___________________ 3

Botanical Art Exhibition __________________________________________________ 3

SAAB Annual General Meeting ____________________________________________ 3

SAAB Student Council Meeting ____________________________________________ 3

Student Gathering _______________________________________________________ 4

Parking ________________________________________________________________ 4

Refreshments ___________________________________________________________ 4

Meals __________________________________________________________________ 4

Prizes __________________________________________________________________ 5

Security ________________________________________________________________ 5

Internet access___________________________________________________________ 5

Emergency______________________________________________________________ 5

INSTRUCTIONS TO PRESENTERS OF ORAL PRESENTATIONS_________6

INSTRUCTIONS TO PRESENTERS OF POSTER PRESENTATIONS ______6

INSTRUCTIONS TO CHAIRPERSONS_________________________________7

SPONSORS _________________________________________________________7

ACKNOWLEDGEMENTS ____________________________________________8

LOCAL ORGANISING COMMITTEE MEMBERS_______________________8

MAP OF POTCHEFSTROOM_________________________________________9

MAP OF POTCHEFSTROOM CAMPUS (NORTH-WEST UNIVERSITY) __10

PROGRAMME OVERVIEW _________________________________________11

POSTER TITLES AND NUMBERS____________________________________16

PLENARY ABSTRACTS_____________________________________________18

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PAPER ABSTRACTS________________________________________________22

POSTER ABSTRACTS ______________________________________________52

INDEX OF AUTHORS_______________________________________________72

GENERAL INFORMATION

Congress Programme

The scientific programme will be held in the J.C. Coetzee building (E8; please refer

to the map on page 10). The proceedings consist of of 5 plenary lectures, 53

contributed oral and 34 poster presentations. We welcome our invited speakers, Proffs

Mick McCormick (Melbourne University), Jill Farrant (University of Cape Town),

Karen Esler (Stellenbosch University), Kevin Balkwill (University of the

Witwatersrand) and Sarel Cilliers (North-West University). The oral presentations

will be split into two parallel sessions through the two days of the Congress, and will

be held in lecture halls G41 and G42 in the J.C. Coetzee building (E8). Posters will be

displayed in the basement of the J.C. Coetzee building (E8). No formal oral

presentations of posters are required, but presenters are urged to man their posters

during the indicated slots for poster sessions in the programme.

Congress Workshop (An introduction to Bayesian statistics for ecologists)

The presenter of this workshop is Dr. Mick McCarthy from the University of

Melbourne in Australia. Mick is the author of a book with the same title as the

workshop. Purchasing the book is compulsory for attending the workshop. The book

will be for sale at the workshop. Here follows a brief extract from the introductory

chapter of his book: "There is a revolution brewing in ecology. Granted, it is a gentle

and slow revolution, but there is growing dissatisfaction with the statistical methods

that have been most commonly taught and used in ecology. One aspect of this

revolution is the increasing interest in Bayesian statistics. This book aims to foster the

revolution by making Bayesian statistics more accessible to every ecologist."

The workshop will be held in NW118 (Natural Sciences building; see map on page

10) on 14 and 15 January from 09:00-17:00, with coffee and tea breaks in the morning

and afternoon and lunch from 13:00-14:00. All beverages and lunches are included.

Workshop information was sent to participants in December, including a powerpoint

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presentation with the contents of the workshop. Participants may bring their own data

for analysis, but it would be best if they contact the presenter

([email protected]) before the workshop to discuss its inclusion.

Congress Excursion (1 day excursion to the Vredefort Dome)

We will meet at 08:00 on Wednesday 13 January in front of the J.S. van der Merwe

building (E6; map on page 10). Our tourleader, local geologist, Cobus van Rensburg

will start the day with an introductory lecture on the geological wonders of the Dome.

At about 09:00 we will leave Potchefstroom and will follow a circular route exploring

the various geological phenomena and associated vegetation in the North-West and

Free State sides of the Dome. Lunch at Bala Bala Game Lodge is included and a cash

bar will be available. We will be back in Potchefstroom at 17:00.

Botanical Art Exhibition

The Botanical Artists' Association of Southern Africa (BAASA) is a non-profit

organisation dedicated to promoting public awareness of botanical art. BAASA is

open to all botanical artists, whether scientific illustrators or realistic flower painters,

as well as collectors and those interested in furthering the tradition of botanical art.

The membership of the Gauteng branch, whose members are represented in this

exhibition, is currently just over 70.

SAAB Annual General Meeting

The AGM is scheduled for Tuesday, 12 January 2010 at 16:30 in G42, J.C. Coetzee

building (E8; see map on page 10). All SAAB members are urged to attend, as very

important decisions are often taken at this meeting. The agenda of the 2010 AGM and

minutes of the 2009 AGM are posted on the notice board at the desk of the SAAB

secretary in the Foyer, J.C. Coetzee building (E8).

SAAB Student Council Meeting

The annual student meeting will be held on 11 January at 17:30 in G42, J.C. Coetzee

building (E8; see map on page 10), where a short report of the past year’s activities

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will be given. A new student council member for the 2010/2011 period will be elected

and time will be allowed for people to voice their ideas on the following year’s

activities.

Student Gathering

The annual SAAB function for students will take place at 19:00 in the NWU

Botanical Garden (map on page 10), after the Student Council Meeting. This is the

perfect opportunity to meet with fellow students from different universities and

broaden our boundaries.

Parking

Delegates may park on campus at the specified zones marked on the campus map on

page 10. You are urged to avoid reserved zones as you may endure a traffic fine.

Delegates who park in the proper zones and receive traffic fines for not having

parking disks, must please report the incident to the information desk in the Foyer,

J.C. Coetzee building (E8) to have it waived.

Refreshments

Tea and coffee are served mid-morning and mid-afternoon in the Foyer, J.C. Coetzee

building (E8). Mid-morning tea will also include some snacks.

Meals

Lunch is served between 13:00 and 14:00 in the basement of the J.C. Coetzee building

on 12 and 13 January 2009. Lunches during the workshop will be served at K01, J.S.

van der Merwe building (E6). On Sunday evening, cocktail snacks and refreshments

are available at the Meet and Greet function at the Science Centre. On Monday

evening, cocktail snacks and refreshments are available at the Botanical Art Function

at the Botanical Garden. Students should also attend the SAAB sponsored Student

Gathering in the Botanical Garden where food and drink will be provided. On

Tuesday evening, the SAAB Dinner will be held in the Alumni Hall. Please note that

we have catered only for delegates who have given prior indication that they wish to

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attend the Meet and Greet, Botanical Art Function and SAAB Dinner. Delegates not

attending these functions are responsible for their own meals. We have made special

culinary arrangements for those delegates who have indicated their preferences in the

registration form.

Prizes

SAAB awards a number of prizes during its annual congress:

• Best Young Botanist – Best paper delivered by a young botanist – under 30 years

of age. First, second and third places are announced.

• Hannes van Staden Prizes – Best papers delivered by a MSc and PhD student.

Only first prize announced for each degree. May be the same candidates as above.

• Prizes for the best poster in each category, namely Applied Botany, Ecology,

Systematics/Taxonomy, and Plant Physiology/Molecular Biology.

Security

Potchefstroom is generally a safe place, and the University provides 24-hour security,

but delegates are urged to take normal precautions. We advise that you do not walk

around at night.

Internet access

An internet café is in close proximity to the conference venue. See map on page 10 for

more details. The café is open from 08:00-17:00. Rates are R5/30 min. Portals for

laptops are also available.

Emergency

In case of a medical or other emergency, please call the following numbers for

assistance:

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Emergency numbers

Service Telephone number After hours

NWU emergency number 018-299 2211 All hours Police 10111 Medi Clinic Potchefstroom 018-293 0244 Business hours 24 Emergency centre 018-294 5644 All hours Medicross healthcare group (doctors and dentist)

018-293 7800 Business hours

Dr. Dennis du Toit (dentist) 018-294 4324 082 800 0856 Kampus Apteek Cachetpark Meyer Street

018-294 4072 082 741 5097

INSTRUCTIONS TO PRESENTERS OF ORAL PRESENTATIONS

Electronic media should be given to the technical assistants at the relevant venue at

least 30 minutes before the start of the session in which you are presenting. G40, J.C.

Coetzee building (E8) is available for previewing Power Point presentations.

Speakers please note that all oral presentations are limited to 20 minutes, that is 15

minutes presentation and 5 minutes for questions. Plenary presentations are limited to

40 minutes, 35 minutes presentation and 5 minutes for questions. Delegates are

expected to adhere strictly to the time given and must also be ready to start on time.

INSTRUCTIONS TO PRESENTERS OF POSTER

PRESENTATIONS

Posters should be mounted in the spaces indicated in the basement of J.C. Coetzee

building (E8). The local organizing committee will provide necessary assistance and

materials to mount your poster on Sunday afternoon (from 16:00) or early Monday

morning (before 09:00). Please remove your poster on Tuesday evening before the

SAAB dinner.

Authors are expected to be available at their posters during the poster sessions to

answer questions. Monday’s session is compulsory for posters in the Applied Botany

and Ecology categories and Tuesday’s session for the Plant Physiology/Molecular

Biology and Systematics/Taxonomy categories.

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INSTRUCTIONS TO CHAIRPERSONS

Chairpersons are asked to adhere to the programme strictly to prevent sessions from

extending beyond the allocated time. Specifically, chairpersons are asked to:

• Identify three referees to complete evaluation forms;

• Be ready to start the session on time;

• Briefly introduce each speaker;

• Indicate to speakers when 10 minutes have passed;

• Indicate when 15 minutes have elapsed, and to ask speakers to conclude;

• Encourage questions and discussion up to the 20-minute time limit;

• Collect evaluation forms and return to local organizing committee.

SPONSORS

We would like to thank the following:

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ACKNOWLEDGEMENTS

We gratefully acknowledge, with many thanks, the following people and organisations:

• Kobus Pienaar, Dean, Faculty of Natural Sciences, North-West University, Potchefstroom

• Huib van Hamburg, Director, School of Environmental Sciences and Development, North-West University, Potchefstroom

• Leon van Rensburg, Director, School of Environmental Sciences and Management, North-West University, Potchefstroom

• Klaus Kellner, Botany Chairperson, School of Environmental Sciences and Development, North-West University, Potchefstroom

• Christo Reitz, Manager, Briza Publications, Pretoria • Kim Rudman, Publicist, Random House Struik, Houghton • Jill Farrant, SAAB President • Karen Esler, SAAB Vice-president • Myke Scott, SAAB Secretary • Chairpersons of the sessions • The Botanical Artists' Association of Southern Africa (BAASA)

LOCAL ORGANISING COMMITTEE MEMBERS

Chairman: Stefan Siebert Secretary: Arthurita Venter Commitee: Sanet Janse van Vuuren

Sandra Barnard Jacques Berner Martin Smit Danie Huyser Sarel Cilliers Anine Jordaan Marie du Toit

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MAP OF POTCHEFSTROOM

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MAP OF POTCHEFSTROOM CAMPUS (NORTH-WEST UNIVERSITY)

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PROGRAMME OVERVIEW

Sunday, 10 January 2010

Start End

14:00 16:00 SAAB Council Meeting [VENUE: Seminar Room, G24, J.S. van der Merwe building (E6)] 15:00 18:00 Registration [VENUE: Science Centre (F14)] 18:00 20:00 Meet & Greet [VENUE: Science Centre (F14)]

Monday, 11 January 2010

Start End 07:15 08:00 Registration [Foyer, J.C. Coetzee building (E8)] 08:00

08:20

VENUE: G42, J.C. Coetzee building (E8) Opening: Prof. Kobus Pienaar (Dean of the Faculty of Natural Science, North West-University, Potchefstroom Campus) Welcome: Prof. Jill Farrant (President of SAAB)

08:20

09:00

PLENARY SESSION 1

Chair: Stefan Siebert

VENUE: G42, J.C. Coetzee building (E8) J.M. Farrant Mechanisms of desiccation tolerance in resurrection plants: a review from the molecular to whole plant physiological level

09:00

09:40

PLENARY SESSION 2

Chair: Sarel Cilliers

VENUE: G42, J.C. Coetzee building (E8) M.A. McCarthy Allocation of resources for protecting biodiversity

09:40 10:20 TEA [Basement, J.C. Coetzee building (E8)] PARALLEL SESSION 1A: TAXONOMY AND DIVERSITY

Chair: Stefan Siebert VENUE: G42, J.C. Coetzee building (E8)

PARALLEL SESSION 1B: PLANT PROPAGATION &

MOLECULAR BIOLOGY

Chair: Hannes van Staden

VENUE: G41, J.C. Coetzee building (E8) 10:20 10:40 M. Struwig, A. Jordaan, S.J. Siebert, L.R. Tiedt

Morphological and anatomical adaptations of Boerhavia L. and Commicarpus Standl. to survive in arid environments of Namibia

A.J. McCormick, N.J. Kruger Arabidopsis thaliana knockout mutants lacking fructose 2,6-bisphosphate have decreased growth rates under fluctuating environmental conditions

10:40 11:00 A.N. Moteetee, B.-E. van Wyk Taxonomic studies on the genus Dolichos (Phaseoleae, Fabaceae) in South Africa

A.M. Zobolo Propagation and growth of Boweia volubilis from bulbs

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Monday, 11 January Cont./...

11:00 11:20 M.M. le Roux, B.-E. van Wyk, J.S. Boatwright, P.M. Tilney, A.N. Moteetee The taxonomic value of fruit wall structure in the genus Crotalaria (Fabaceae, tribe Crotalarieae)

P.D. Nkwanyana, S.J. Snyman, M.P. Watt Micropropagation of sugarcane (Saccharum spp. hybrids) in vitro: a comparison between semi-solid and liquid RITA® temporary immersion culture systems with respect to plant production and genotypic and phenotypic fidelity

11:20 11:40 E. Retief, T.T. Masupa The genus Pelargonium (Geraniaceae) in southern Africa

V.N.P. Ngunge, J.F. Finnie, J. van Staden Micropropagation of Tulbaghia species

11:40 12:00 S. Kurzweg, S.J. Siebert, S.S. Cilliers, K. Kellner

Assessing the floristic importance of proposed conservation areas in North-West Province in the context of the western Central Bushveld Bioregion

S.G. van Wyk, K.J. Kunert, B.J. Vorster, U. Schluter Interaction of cysteine protease inhibitor mutants with cysteine proteases

12:00 12:20 A.A. Levanets, J.C. Taylor, A. Venter, S. Janse van Vuuren, L. van Rensburg Preliminary report on algae and cyanoprokaryota diversity in the Drakensberg

P. Pillay, J. Vorster, K.J. Kunert, U. Schluter Influence of plant-derived protease inhibitors on the expression of the VP1 antigen from foot-and-mouth disease virus in tobacco

12:20 12:40 W. van Staden, S. Janse van Vuuren, V. Smith, L. van Rensburg Freshwater algae (excluding diatoms) of the Sub-Antarctic Marion Island

B.J. Vorster, Ö. Tastan Bishop, K.J. Kunert, D. Michaud Modeling plant cystatins for targeted activity in a multi-trophic context

12:40 13:00 M. Rouget, T. Smith, A. Driver Identifying threatened terrestrial ecosystems in South Africa

L.J. Rice, G.D. Ascough, J.F. Finnie, J. van Staden DNA fingerprinting of Plectranthus plants for protection of cultivar registration

13:00 14:00 LUNCH [Basement, J.C. Coetzee building (E8)] 14:00

14:40

PLENARY SESSION 3


VENUE: G42, J.C. Coetzee building (E8) K. Balkwill Can conservation of biodiversity provide an evolutionary advantage to humans?

PARALLEL SESSION 2A: ETHNOBOTANY

Chair: Alpheus Zobolo

VENUE: G42, J.C. Coetzee building (E8)

PARALLEL SESSION 2B: PHYSIOLOGY

Chair: Gert Krüger

VENUE: G41, J.C. Coetzee building (E8) 14:40 15:00 B.-E. van Wyk

A review of ethnobotanical studies in the Cape region of South Africa J. van Staden, W.A. Stirk, O. Novák, M. Strnad

The role of cytokinins in seed germination

15:00 15:20 P.M. Tilney, B.-E. van Wyk The value of anatomy in pharmacognosy and forensic studies

M. de Beer, A. Jordaan, P.D.R. van Heerden

Low night temperatures inhibits symbiotic nitrogen fixation and affects the potential for recovery in a chilling sensitive soybean genotype

15:20 15:40 O.A. Wintola, A.J. Afolayan Ethnobotanical survey of plants used for the treatment of constipation in Nkonkobe Municipality of South Africa

M.M. Minnaar, J.M. Berner, G.H.J. Krüger

Sulphur dioxide fumigation leads to increases in antioxidant enzymes and changes in the photosynthetic capability of canola plants (Brassica napus L.)

15:40 16:00 TEA [Basement, J.C. Coetzee building (E8)]

13

Monday, 11 January Cont./... 16:00 16:20 I.M. Hulley, B.-E. van Wyk, P.M. Tilney, G.P. Kamatou, A.M. Viljoen,

S.F. van Vuuren A review of Pteronia species used in traditional medicine in South Africa

M.W. Bairu, O. Novák, K. Doležal, J. van Staden Changes in endogenous cytokinin profiles in micropropagated Harpagophytum procumbens in relation to shoot-tip necrosis and cytokinin treatments

16:20 16:40 L. Cheesman, J.F. Finnie, M.E. Light, J. van Staden In vitro propagation and secondary metabolite production of Boophone disticha

C.C.W. Scheepers, J.M. Berner, G.H.J. Krüger Protective effect of the anti-ozonant, ethylenediurea (EDU), on development and photosynthesis of Glycine max under ambient and elevated ozone levels in an OTC system

16:40 17:00 C. Bvenura, A.J. Afolayan Analysis of heavy metal contamination in home gardens in Alice, Nkonkobe municipality, Eastern Cape, South Africa

S. Lindeque, J.M. Berner, G.H.J. Krüger Antioxidant metabolism changes in soybeans (Glycine max) in response to sulphur dioxide fumigation

17:00 17:30 POSTER SESSION 1: Applied Botany and Ecology Chair: Jacques Berner

VENUE: Basement, J.C. Coetzee building (E8) 17:30 18:30 Student Council Meeting [VENUE: G42, J.C. Coetzee building (E8)] 18:00 22:00 Botanical Art Function [VENUE: Botanical Garden (H5)] 19:00 23:30 Student Gathering [VENUE: Botanical Garden (H5)]

Tuesday, 12 January 2010

07:15 08:00 Late Registration [Foyer, J.C. Coetzee building (E8)] 08:00

08:40

PLENARY SESSION 4

Chair: Klaus Kellner VENUE: G42, J.C. Coetzee building (E8)

K.J. Esler Arid Ecosystems and Academia: how competition and facilitation interactions shape community structure and function

08:40

09:20

PLENARY SESSION 5


VENUE: G42, J.C. Coetzee building (E8 S.S. Cilliers Urban areas in South Africa – final frontier for Ecology?

09:20 10:00 TEA [Basement, J.C. Coetzee building (E8)] PARALLEL SESSION 3A: ETHNOBOTANY

Chair: Ben-Erik van Wyk


PARALLEL SESSION 3B: APPLIED ECOLOGY

Chair: George Bredenkamp

VENUE: G41, J.C. Coetzee building (E8) 10:00 10:20 A.O. Aremu, J.C. Chukwujekwu, M.E. Light, J.F. Finnie, J. van Staden

Preliminary studies on the in vitro pharmacology of Leucosidea sericea L. le Grange, G.J. Bredenkamp, J.H.J. Schaminée The vegetation ecology of the Seringveld Conservancy, Cullinan, South Africa

14

Tuesday, 12 January Cont./... 10:20 10:40 N.R. Sathekge, Q. Kritzinger, G. Prinsloo

Comparison of secondary metabolite content and antimicrobial activity of four Hypoxis species used in traditional medicine

S.O. Oke, G.A.O. Ibhanesebhor Impact of limestone quarrying on the vegetation of Ewekoro Cement Factory Site, Nigeria

10:40 11:00 E.J. Mavundza, T.E. Tshikalange, N. Lall, F.N. Mudau, A.A. Hussein Antioxidant activity and cytotoxicity of three flavonoids from Athrixia phylicoides ethanol extract

C.V. Helm Investigating the vulnerability of marula stems to fire and bark stripping

11:00 11:20 H.S. Abdillahi, J.F. Finnie, J. van Staden Antioxidant and anti-inflammatory activities and phenolic content of Podocarpus sensu latissimo (s.l.) used in traditional medicine in South Africa

E. Davoren, S.S. Cilliers, S.J. Siebert Plant diversity patterns of a settlement in the North-West Province, South Africa

11:20 11:40 H.S. Long, B.-E. van Wyk, P.M. Tilney Ethnobotany and pharmacognosy of three Cape herbal plants

T. Hodges, A. Robertson, J. Rapson, L. Schipper, B. Clarkson Increased nutrient inputs to remnant lowland restiad mires in an agricultural landscape: Impacts on capillaroid root growth, biomass production and decomposition processes

11:40 12:00 R.B. Mulaudzi, M.G. Kulkarni, J.F. Finnie, J. van Staden Antimicrobial and phytochemical evaluation of twelve medicinal plants used by the Venda People

A.S. Rossouw, H.J. Annegarn, I.M. Weiersbye, D.G. Furniss Evaluating the functional status of a rehabilitated gold tailings storage facility – a case study in the Witwatersrand

12:00 12:20 C.J. Henley-Smith, N. Lall, F. Botha South African plant extracts in combating potentially pathogenic oral microorganisms

M. Westcott, K. Kellner, J.M. Berner The evaluation of the effect of seed coating on the germination of three perennial grass seed types in different growth mediums

12:20 12:40 A.A. Badmus, A.J. Afolayan Foliar micromorphology and phytotoxicity of Arctotis arctotoides on some vegetable seeds

J. Roux, S. van der Merwe, E. Malan, M.W. van Rooyen, M.J. Wingfield South African native trees increasingly threatened by diseases

12:40 13:00 M. Chinsamy, J.F. Finnie, J. van Staden Going back to our roots: Orchids and the ancestors

J.A. van der Linde, D. Six, M.J. Wingfield, J. Roux Consideration of factors associated with Euphorbia ingens decline in the Limpopo Province of South Africa.

13:00 13:45 LUNCH [Basement, J.C. Coetzee building (E8)] 13:45 14:20 GROUP PHOTO [Amphitheater] PARALLEL SESSION 4A: MEDICINAL PLANT SCIENCES

Chair: Patricia Tilney


PARALLEL SESSION 4B: BIOTECHNOLOGY & INVASION

Chair: Marion Meyer

VENUE: G41, J.C. Coetzee building (E8) 14:20 14:40 A.A. Hussein, M. Meyer, N. Lall

Lead compounds from traditional medicine, practical point of view A.C. Koch, S. Ramgareeb, S.J. Snyman, M.P. Watt, R.S. Rutherford

Pursuing imazapyr herbicide tolerance in sugarcane: screening plants produced in vitro through somaclonal variation and mutagenesis

14:40 15:00 M.S. Deutschländer, N. Lall, M. van de Venter Isolation and identification of a novel anti-diabetic compound from Euclea undulata Thunb

C.B.S. Hendriks, J.M.M. Meyer, C.F. van der Merwe Do symbiotic plant microbes play a role in the synthesis of the toxic compounds of Dichapetalum cymosum?

15:00 15:20 G. Prinsloo, J.C. Viljoen, C.P. du Plooy Nitrogen fertiliser requirements of medicinal plants

T.M. Mokotjomela, C.F. Musil, K.J. Esler Are fleshy fruits of alien shrubs a preferred food resource for avian frugivores in the Cape Floristic Region?

15

Tuesday, 12 January Cont./... 15:20 15:40 K.M. Swanepoel, W.G. Alberts

Species with potential for Industrial Crops in South Africa

15:40 16:00 TEA [Basement, J.C. Coetzee building (E8)] 16:00 16:30 POSTER SESSION 2: Plant Physiology/Molecular Biology and Systematics/Taxonomy

Chair: Jacques Berner

VENUE: Basement, J.C. Coetzee building (E8) 16:30 18:00 SAAB Annual General Meeting [VENUE: G42, J.C. Coetzee building (E8)] 18:30 22:00 SAAB Dinner [VENUE: Alumni Hall (F14)]

Wednesday, 13 January 2010

Start End

08:00 17:00 Excursion to Vredefort Dome Tour Guide: Kobus van Rensburg

DEPARTURE FROM: J.S. van der Merwe building (E6)

Thursday, 14 and Friday, 15 January 2010

Start End

08:30 18:00 Workshop on Bayesian Statistics Presenter: Mick McCarthy

VENUE: NW118, Natural Sciences Building (G1)

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POSTER TITLES AND NUMBERS

# Name Title Session

1 A.J. Afolayan, P.O. Adebola

Plant regeneration from seed-derived callus of Arctotis arctotoides (L.F.) O. Hoffm: A medicinal herb of the family Asteraceae

Applied Botany

2 T.P. Jaca, M.A. Kganye, L. Venter

Emerging invasive alien plant survey for prioritisation in Gauteng protected areas, South Africa

Applied Botany

3 L. Kafua, Q. Kritzinger, A.A. Hussein

Antifungal activity of Gardenia brighamii leaf extracts Applied Botany

4 M.A. Kganye, T.P. Jaca, L. Venter

Identification and prioritising invasive alien plants hot spot areas in Gauteng

Applied Botany

5 R. Khanum, A.S. Mumtaz, S. Ahmed

Did the dominant plant species of valley floras change as a result of the 2005 earthquake in Kashmir (with emphasis on the Neelum and Jhelum Valleys)

Applied Botany

6 M.M. Magodielo, S.J. Siebert, S.S. Cilliers, F.P. Retief

A critical assessment of plant resource utilization and park expansion in North-West

Applied Botany

7 L.Y. Molebatsi, S.J. Siebert, S.S. Cilliers, M. Struwig, A. Kruger

A comparative floristic analysis of peri-urban and rural homegardens in North-West, South Africa

Applied Botany

8 G.L. Ngwenya , N. Moodley, M.E. Nemutanzhela, B.G. Crampton

A micropropagation protocol for Siphonochilus aethiopicus, an endangered South African medicinal plant

Applied Botany

9 M. Nkomo, E.J. Ndebia, B.N. Nkeh-Chungag, L. Kambizi, J.E. Iputo

Antinociceptive and anti-inflammatory investigation of Heteromorpha arborescens (Apiaceae) in animal experimental models

Applied Botany

10 H.B. Papenfus, Q. Kritzinger

Efficacy of selected plant extracts against fungal pathogens of onion Applied Botany

11 M. Rouget, J. Blignaut, B. Egoh

Creating markets for ecosystem services Applied Botany

12 J.M. van der Hout, J.J.M. Meyer

The effect of water stress on the concentration of artemisinin and other metabolites in Artemisia annua L.

Applied Botany

13 B. Slippers, J. Roux, D. Begoude, J. Mehl, J.A. van der Linde, D. Pavlic, F. van der Walt, H. Maleme, B. Hinze, G. Marais, B.D. Wingfield, M.J. Wingfield

Diverse communities of the Botryosphaeriaceae infect native trees in Southern Africa

Applied Botany

14 C.L. Bredenkamp, P. Gozo, E.T. Rampho

When botany blooms, biodiversity benefits: celebrating botany during the 2010 International Year of Biodiversity

Applied Botany

15 F.P. Begwa, M.P. Tshisikhawe, M.H. Ligavha-Mbelengwa

Classification of a grassland community along the floodplain of Nylsvlei Nature Reserve, Limpopo Province, RSA

Applied Botany

16 S.P. Mashile, M.P. Tshisikhawe, M.H. Ligavha-Mbelengwa

Tree layer species composition of the Nylsvley Nature Reserve woodland community, in Limpopo Province, South Africa

Applied Botany

17 M.J. du Toit, S.S. Cilliers, T.C. de Klerk

Comparing urban areas: quantifying urbanization using a gradient approach

Ecology

18 T. Hodges, A. Robertson, J. Rapson, L. Schipper, B. Clarkson

Nutrient cycling and decomposition processes in New Zealand montane restiad mires: assessing above and belowground biomass pools along internal and external mire gradients

Ecology

19 A.J.H. Lamprecht, S.S. Cilliers, A.R. Götze

Plant communities of the area leased for mining purposes by Impala Platinum, Rustenburg

Ecology

17

20 C.S. Lubbe, S.J. Siebert, S.S. Cilliers

Plant diversity in urban domestic gardens along a socioeconomic gradient in the Tlokwe Municipal area, North-West Province

Ecology

21 M. Treurnicht, K.J. Esler, M. Gaertner

Impacts of ploughing and introduction of commercial fynbos species on the diversity of sandstone fynbos on the Agulhas Plain, South Africa

Ecology

22 M. Strydom, K.J. Esler, A.R. Wood

Seed bank status and dynamics of Acacia saligna at two sites in the Western Cape, South Africa

Ecology

23 J.D. Hakizimana, M. Gryzenhout, T.A. Coutinho, N. van den Berg

Isolation and identification of endophytes from avocado roots Systematics/ Taxonomy

24 S. Kurzweg, S.J. Siebert, S.S. Cilliers, K. Kellner

Floristic diversity and phytogeography of the proposed Heritage Park in North-West Province, South Africa

Systematics/ Taxonomy

25 M. Struwig, S.J. Siebert, A. Jordaan, P.M. Burgoyne

Anthocarp structure as a diagnostic character for Boerhavia L. and Commicarpus Standl. species in southern Africa


26 A. Venter, A.A. Levanets, J.C. Taylor

Algal diversity on the rock-faces of the Golden Gate National Park


27 S.A. Gilani, R.A. Qureshi, D. Potter

The pollen morphological characterization of selected species of Prunus using Scanning Electron Microscopy


28 J.L. Arnolds, C.F. Musil, G.H.J. Krüger

The effects of experimental climate warming on the germination, flowering and physiology of different fynbos species

Physiology/ Molecular Biology

29 N. Devnarain, S.J. Snyman, C. Hunter, S.A. McFarlane, R.S. Rutherford

The establishment of in vitro screening methods for evaluating sugarcane (Saccharum spp. hybrids) susceptibility to Ustilago scitaminea H. & P. Sydow and Eldana saccharina Walker


30 L.-D. de Wet, M.J. Wingfield, B.D. Wingfield, E.T. Steenkamp

Evaluation of the ribosomal RNA intergenic spacer region as a diagnostic marker for Fusarium circinatum


31 B.J. Farrow, G. Fourie, N. van den Berg

DNA profiling of Persea americana using AFLP markers Physiology/ Molecular Biology

32 W. Mahomed, A.A. Myburg, N. van den Berg

Sequencing the avocado transcriptome Physiology/ Molecular Biology

33 M.E. Nemutanzhela, B.G. Crampton, D. Mancama

Establishment of Artemisia sp. plant cell suspension cultures Physiology/ Molecular Biology

34 L. Mohase, B.M. Taiwe Elucidation of defence responses induced by aphid saliva Physiology/ Molecular Biology

18

PLENARY ABSTRACTS

Abstracts are arranged in alphabetical order according to the presenting author’s surname.

The presenter of the paper is underlined.

19

Can conservation of biodiversity provide an evolutionary advantage to humans?

K. Balkwill C.E. Moss Herbarium, School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Private Bag 3, WITS, 2050, South Africa

Humans have a long history of conserving natural areas and the biodiversity they contain or represent. The wide variety of motivations for doing so includes duty, the desire to preserve the potential to acquire natural products that might be found in the areas, efforts to conserve rare and endangered species, maintaining ecosystem services, capitalising on the potential financial benefits of ecotourism and earning finances through carbon credits. Cynics suggest that the desire to conserve biodiversity is simply a means of channelling finances towards a particular sector of the scientific community. Humans are extremely effective environmental engineers, however, and there are risks to being environmental engineers, particularly in recently colonised habitats. The largest risk is that environmental engineers may modify habitats to facilitate population growth, but in doing so may take population levels beyond carrying capacity and thus place themselves at risk of extinction. It appears that the human population growth rate may stabilise, but the average individual consumption rate is very far from stabilising. Indeed, we have an economic system that depends on growing markets and development for its persistence. Some humans still tend to regard human and natural environments as separate entities and fail to see their interconnectedness nor the dire implications of not making such a link. Areas that are left intact in order to conserve biodiversity may well act as cushions against over shooting the carrying capacity of the planet and the ability to do so may represent a barometer of the potential of humans to stem their own progression towards extinction. Thus, the best motivation for humans to conserve biodiversity may be that it imparts an evolutionary advantage over not doing so. Urban areas in South Africa – final frontier for Ecology?

S.S. Cilliers School of Environmental Sciences and Development, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa

Increasing urbanisation results in considerable environmental changes such as transformation and fragmentation of natural habitats, alteration of species composition and depletion of ecosystem services offered by natural ecosystems. Additionally, the socio-economic world of urban residents is impacted upon, both in terms of physical and mental health, as well as social well-being. There is a growing global concern for these problems, culminating in a realisation that the complex socio-ecological nature of urban ecosystems requires an integrated approach in ecological studies of urban environments encompassing biophysical, socio-economic and cultural issues, an approach that is often called “ecology of cities”. Although urban areas are dominated by human-built structures and activities, they should be regarded as functioning ecosystems that possess many of the same components and processes as less human-dominated natural systems. If we are to succeed in creating and managing sustainable cities and towns, a more comprehensive understanding of the structure and function of these ecosystems is essential. An analysis of journal papers published on ecological subjects in South Africa over the last two decades has, however, revealed that urban ecological research in South Africa has not emerged into the ecological mainstream, yet. Many of the few published studies on the ecology of urban areas are of a descriptive nature, and mainly addressed fragmented natural areas inside cities. In this presentation

20

I will explore the challenges, possible approaches and major applications of urban ecological research in South Africa. The importance of an integrated approach towards ecological studies in human settlements will be explained using a selection of case studies.

Arid Ecosystems and Academia: how competition and facilitation interactions shape

community structure and function

K.J. Esler Department of Conservation Ecology & Entomology, Private Bag X1, Matieland, 7602

Ecologists are interested in the relationship between organisms and their environment. Availability of resources and how organisms interact in using them therefore falls within the realm of ecology. Organisms interact in a variety of ways and it is these interactions that shape the structure of the communities of other individuals (academics) and species (disciplines) within their realm of influence. There is also a longer-term, evolutionary consequence of these interactions (institutional structure). In this address, I tie together ecology – the study of interactions of living organisms with each other and their environment – with my vision of academia – the collective term for the scientific and cultural community engaged in higher research and education. I draw analogies between two types of environments, namely arid ecosystems, within which much of my research history resides, and the academic environment, within which I have resided for all of my working life. I will focus on two key interactions, seemingly opposite in type, aligned with my research interests – competition, where the interaction is negative (-/-), and facilitation, where it is positive (+/+), and how these shape communities. From a management point of view, it is extremely useful to understand how these interactions shape community structure. If, for example, something changes in the resource environment, such as the occurrence of a drought or an economic recession, it is useful to know how this may alter community structure so that remedial measures such as the removal of herbivores, active restoration, restructuring or bail-out packages can be considered. Similarly, if we wish to understand why the community is structured like it is (for example, why are women so rarely found in higher echelons of academia?), an examination of the forces structuring the community may assist in this understanding.

Mechanisms of desiccation tolerance in resurrection plants: a review from the molecular to

whole plant physiological level J.M. Farrant Department of Molecular and Cell Biology, University of Cape Town, Private Bag X3, Rondebosch, 7701. South Africa

Desiccation tolerance is common in seeds but rare in the vegetative tissues of most angiosperms. Some 350 species of angiosperm (0.2% of total flora) tolerate desiccation in their vegetative tissues and are termed resurrection plants. Many of these are endemic to Southern Africa. Our research is aimed at gaining an understanding of the mechanisms of desiccation tolerance in general and the similarities and differences among species and between vegetative tissues and seeds. The research is conducted at several levels, from the molecular to the whole plant physiological level. Molecular studies have given insight into some of the genes, proteins and metabolites upregulated during drying and rehydration that may function as protection and/or repair systems. Biochemical studies are used to characterise the nature of protection offered by these

21

molecules and ultrastructural studies to elucidate subcellular location and changes therein during drying and rehydration. This in turn is related to physiological responses from the root to shoot level. In this paper aspects from such studies will be presented for several species and discussed in terms of how these have facilitated our understanding of vegetative desiccation tolerance

Allocation of resources for protecting biodiversity

M.A. McCarthy School of Botany, The University of Melbourne, Parkville, VIC 3010, Australia

Faced with substantial environmental treats, managers must decide how to invest the resources they have available. Managers must choose from a set of possible strategies, determine the level of investment in each, and decide where that effort should be located. For example, when surveying for an invasive weed, a manager needs to determine the methods used to search for the weed, where to look and how much effort to expend. This example is one of a number of problems requiring the allocation of resources to environmental management. Here I will present a theory for making such decisions. Using an example of designing surveys for an invasive weed, I show, not surprisingly, that when the aim is to minimize the expected environmental damage of the weed, sites should be surveyed if the probability of presence and the benefits of detection are sufficiently large. Less intuitively, sites receive the most survey effort where the rate of detection is intermediate because while survey effort is wasted at sites with low rates of detection, little effort is required when rates of detection are high. In this example the aim was to minimize the expected cost, ignoring uncertainty in the effectiveness of management. If we consider uncertainty, managers might aim to maximise the probability of achieving an acceptable outcome. This class of problem becomes very similar to determining the optimal allocation of an investment portfolio among financial assets. Just as some investors might be reluctant to rely solely on one financial asset, if the aim of management is to maximise the probability of achieving a modest goal, the optimal strategy is to diversify investment across a set of assets, depending on the expected benefit, the uncertainty in the benefit, and the attitude to risk. I illustrate this class of problem with investment among the world's biodiversity hotspots to protect endemic plants, and conservation of urban grasslands within Melbourne.

22

PAPER ABSTRACTS

Abstracts are arranged in alphabetical order according to the presenting author’s surname. The presenter of the paper is underlined.

23

Antioxidant and anti-inflammatory activities and phenolic content of Podocarpus sensu

latissimo (s.l.) used in traditional medicine in South Africa

H.S. Abdillahi, J.F. Finnie, J. van Staden Research Centre for Plant Growth and Development, School of Biological and Conservation Sciences, University of KwaZulu-Natal Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa

Extracts of four species of Podocarpus s.l. (P. elongatus, P. falcatus, P. henkelii and P. latifolius) were evaluated for their antioxidant activity (AA) by measuring the ferric-reducing power (FRAP), inhibition of lipid peroxidation using the linoleic acid system and 2,2’-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging activity. The anti-inflammatory activity was assessed using enzyme-based cyclooxygenase assays; COX-1 and COX-2. Total phenolic compounds including condensed tannins, gallotannins and flavonoids were quantitatively determined using spectrophotometric methods. The extracts showed a concentration-dependent antioxidant activity. Stems of P. latifolius exhibited the lowest IC50 (11.2 µg.ml-1) inhibition of DPPH. The percentage antioxidant (% ANT) based on the bleaching rate of β-carotene ranged from 96.1 to 99.4%. In FRAP, the extracts showed ability to reduce Fe3+ by increasing absorbance at 600 nm. At a concentration of 0.6 mg.ml-1 of plant extracts the absorbance ranged from 1.668-1.938. All extracts inhibited COX-1 and COX-2 prostaglandin biosynthesis at a concentration greater than 60%. Stem extracts of P. falcatus and P. latifolius exhibited the highest percentage inhibition (102.43% for COX-1; 96.52% and 97.59% for COX-2 respectively). The lowest IC50 value was exhibited by stem extracts of P. elongatus (5.05 µg.ml-1 for COX-1 and 6.06 µg.ml-1 for COX-2). The total phenolic content based on gallic acid equivalents (GAE) confirmed the presence of total soluble phenolics ranging from 2.38 to 6.94 mg of GAE.g-1 dry sample. There was no significant correlation between the antioxidant activities exhibited and total phenolic content (r2 ≤ 0.1). Hence, besides the composition of phenolics other factors may contribute to the antioxidant activity of plant extracts. The significant anti-inflammatory activities observed could be due to the presence of antioxidant activities. A number of biflavonoids with anti-inflammatory activities have been isolated from other species of Podocarpus s.l.

Preliminary studies on the in vitro pharmacology of Leucosidea sericea

A.O. Aremu, J.C. Chukwujekwu, M.E. Light, J.F. Finnie, J. van Staden Research Centre for Plant Growth and Development, School of Biological and Conservation Sciences, University of KwaZulu-Natal Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa

Leucosidea sericea Eckl. & Zeyh. is a member of the family Rosaceae and the only species in the genus Leucosidea. It is an evergreen tree and native to the Afromontane regions of southern African countries such as South Africa, Swaziland and Lesotho. Pharmacological investigation and information on the species is limited. The shoot of the plant is used as a vermifuge, an astringent and in the treatment of ophthalmia by various African tribes. Organic solvent and water extracts of L. sericea leaves and stems were investigated for antimicrobial, anthelmintic and cyclooxygenase enzyme inhibitory activities. The organic extracts of the leaves and stems exhibited broad spectrum antibacterial activity. The most noteworthy minimum inhibitory concentration (MIC) of 25 µg.ml-1 was displayed by petroleum ether (PE) and dichloromethane (DCM) leaf extracts against Bacillus subtilis and Staphylococcus aureus, respectively. The antifungal test organism Candida albicans was less sensitive to the extracts with 1.56 mg.ml-1 being the best MIC value obtained. In the

24

anthelmintic bioassay, the best minimum lethal concentration (MLC) values of 8.33 mg.ml-1 and 0.26 mg.ml-1 against Caenorhabditis elegans were obtained for the water and organic extracts, respectively. Both leaf and stem organic solvent extracts exhibited a high level of inhibition against COX-1 and -2 enzymes at a maximum concentration of 250 µg.ml-1. The extracts were further tested at three lower concentrations to observe their dose responses and the lowest IC50 values of 0.06 µg.ml-1 (COX-1) and 12.66 µg.ml-1 (COX-2) were exhibited by the PE leaf extracts. Generally, the leaves exhibited better pharmacological activities than the stems. In view of the promising pharmacological activities displayed by L. sericea especially the leaves, we are currently investigating the safety and isolating the bioactive compound(s) as well as the phytochemistry of the plant in our laboratories.

Foliar micromorphology of Arctotis arctotoides (L.F.) O. Hoffm.

A.A. Badmus, A.J. Afolayan

Department of Botany, University of Fort Hare, Alice 5700, South Africa

Arctotis arctotoides is a perennial herb used for the treatment of various diseases. Several

secondary metabolites have been isolated from the plant, some of which are very effective as antimicrobial agents. Scanning electron microscopical examination of the foliar appendages of the plant revealed that its leaf surfaces are characterised by anisocytic stomata, glandular and non-glandular trichomes. The stomata and glandular trichomes are more abundant on the abaxial than the adaxial surfaces of the leaves. Crystal deposits were also observed around the stomata and near the glandular trichomes. Energy dispersive X-ray spectroscopy showed that Al, K, Fe, Ca, Na and Si were the major constituents of the crystals. Naturally, distinct morphological variations exist among the ultra structures on the leaf surfaces of the plant. The distributions of the stomata and the two types of trichomes on both surfaces also differ both in shape and in structure. We postulate that the various bioactive metabolites produced by this herb are from the glandular trichomes found on the leaf surfaces.

Changes in endogenous cytokinin profiles in micropropagated Harpagophytum procumbens in

relation to shoot-tip necrosis and cytokinin treatments

M.W. Bairua, O. Novákb, K. Doležalb, J. van Stadena aResearch Centre for Plant Growth and Development, School of Biological and Conservation Sciences, University of KwaZulu-Natal Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa bLaboratory of Growth Regulators, Palacký University & Institute of Experimental Botany AS CR, Šlechtitelů 11, 783 71 Olomouc, Czech Republic

Changes in tissue cytokinin (CK) profiles and their physiological implications in micropropagated Harpagophytum procumbens in relation to shoot-tip necrosis (STN) and CK treatments were studied. Total CK content was quantified in benzyladenine (BA)-treated necrotic and normal samples and in samples treated with the CKs BA, meta-topolin (mT) and meta-topolin riboside (mTR) with and without the auxin indole-3-acetic acid (IAA). Generally necrotic shoots yielded more total CK compared to normal shoots. Cytokinin accumulation was higher at the basal section (basal > middle > top). Further analysis of the CKs based on structural and functional forms revealed excessive accumulation of 9-glucosides (deactivation products - toxic metabolites) and

25

limited amounts of O-glucosides (storage forms - re-utilisable) on necrotic and BA-treated shoots compared to the normal and topolin-treated cultures. The addition of IAA enhanced the formation of 9-glucosides in BA-treated cultures but reduced it in topolin-treated cultures. The symptom of STN could therefore be attributed to CK deficiency and/or unavailability due to conversion to other forms such as 9-glucosides which are neither active nor convertible to active forms. These lower levels of active CKs cause cessation of cell division and death of meristematic tissues resulting in STN.

Analysis of heavy metal contamination in home gardens in Alice, Nkonkobe Municipality,

Eastern Cape, South Africa

C. Bvenura, A.J. Afolayan Department of Botany, University of Fort Hare, Alice 5700, South Africa

Despite the growing concern worldwide over the accumulation of heavy metals in soils, due to environmental pollution especially in agricultural soils and industrial sites, less attention is focused on possible accumulation of heavy metals in small home gardens where most families cultivate various crops to supplement their incomes or for diet fortification. Both organic and inorganic fertilisers and other agrochemicals are applied in some of the gardens. This study examined the accumulation of some of the essential but heavy or toxic metals (Cu, Mn and Zn Cd and Pb) in some local vegetables (cabbage, carrot, onion, spinach and tomatoes) which are cultivated in home gardens around Alice in Nkonkobe Municipality of the Eastern Cape. Samples of these vegetables were randomly collected from residential areas and analysed using the AAS. The results showed that Zn in onion ranged between 21.43-297.63 ppm but was much lower in cabbage, ranging between 2.28 and 5.65 ppm and 12 to141.10 ppm in spinach. Mn ranged between 20.27 and 23.88 ppm in onion, 12.50 to 132.72 ppm in cabbage and 62.27-126.35 ppm in spinach. Cu was below detectable levels in all the three vegetables. The results further show that there is Zn and Mn contamination in some of the gardens especially those close to traffic roads and those collected from soils whose fertility was boosted by application of fertilisers.

In vitro propagation and secondary metabolite production of Boophone disticha

L. Cheesman, J.F. Finnie, M.E. Light, J. van Staden Research Centre for Plant Growth and Development, School of Conservation and Biological Sciences, University of KwaZulu-Natal Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa

Boophone disticha (L.f.) Herb. (Amaryllidaceae) is distributed throughout southern Africa and is widely known for its poisonous and medicinal properties. B. disticha is of considerable ethnobotanical interest in traditional medicine because of its hallucinogenic alkaloids. It is in high demand and is commonly found in ‘muthi’ shops and traditional plant markets. Although it is not considered threatened in South Africa, this is likely to change due to high harvesting rates. In Lesotho B. disticha is already endangered. Twin-scale explants were placed on solid Murashige and Skoog media containing 2 g.l-1 charcoal, 150 mg.l-1 ascorbic acid and supplemented with various concentrations of NAA and BA. Cultures were placed in a 16 h light / 8 h dark regime at 25 °C. Bulblets formed on media supplemented with 0:0, 5.37:44.4, 26.85:44.4 and 53.7:44.4 µM NAA:BA. Seasonal variation in biological activity of various plant parts is currently being

26

investigated. Extracts from roots, inner scales and outer scales of B. disticha bulbs collected in winter were evaluated for antibacterial activity. The dichloromethane extract of roots showed a minimum inhibitory concentration (MIC) of 1.56 mg.ml-1 against Staphylococcus aureus and Bacillus subtilis. Outer bulb scales showed higher activity than inner bulb scales. Screening for antibacterial and antifungal activity is currently being carried out with B. disticha bulbs collected in spring.

Going back to our roots: Orchids and the ancestors

M. Chinsamy, J.F. Finnie, J. van Staden Research Centre for Plant Growth and Development, School of Biological and Conservation Sciences, University of KwaZulu-Natal Pietermaritzburg, Private Bag X01, Scottsville 3201, South Africa

This is an investigation into the antimicrobial activity and secondary metabolite profile of seven orchid species; Ansellia africana, Bulbophyllum scaberulum, Cyrtorchis arcuata, Eulophia petersii, Eulophia speciosa, Polystachya pubescens and Tridactyle tridentata, traditionally used for medicine in South Africa. Aqueous, petroleum ether, dichloromethane (DCM) and 80% ethanol extracts were evaluated for antimicrobial activity. Antibacterial and antifungal capacities were determined using separate bioassays, where the antibacterial test organisms included two Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus) and two Gram-negative bacteria (Escherishia coli and Klebsiella pneumonia). Candida albicans served as the fungal agent in the antifungal bioassay. Only Eulophia species, root extracts, exhibited significant activity (scored at less than 1 mg.ml-1) against Gram-negative bacteria (from 0.65-0.78 mg.ml-1) while Gram-positive bacteria were susceptible to most extracts. Candida albicans was most susceptible to Eulophia (isaha) DCM stem and pseudobulb extracts, with fungicidal concentrations of 0.78 mg.ml-1 and 0.65 mg.ml-1 respectively. Tridactyle tridentata DCM and aqueous extracts produced the highest inhibitory activity against Gram-positive bacteria (<0.097 mg.ml-1). Methanol extracts were used to determine the chemical profiles of these species. Total phenolic content which includes gallotannin, condensed tannin and flavonoid content were quantitatively determined while thin layer chromatography was used to determine alkaloid content. The determination of total phenolics using the Folin-Ciocalteu method revealed Eulophia petersii pseudobulb extract as containing the highest total phenolic content (24.73±0.57 mg gallic acid equivalent (GAE).g-1 dry matter). Condensed tannin (syn. proanthocyanidin) content was highest for Cyrtorchis arcuata leaf extract (1.36 mg leucocyanidin equivalent.g-1 dry matter). Hydrolysable tannin (gallotannin) content varied among species with Eulophia speciosa root extract containing the highest amount (1.40 mg GAE.g-1). The highest flavonoid content was recorded at 1.24 mg catechin equivalent/g dry matter for Cyrtochis arcuata stem/root extract.

Plant diversity patterns of a settlement in the North-West Province, South Africa

E. Davoren, S.S. Cilliers, S.J. Siebert School of Environmental Sciences and Development, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa

In recent years the composition of urban vegetation has become far more complex than that of the surrounding natural vegetation. This is mainly due to the influence that humans have on the

27

creation of new plant communities and the management of urban green spaces. Green spaces are fundamental to the restoration and maintenance of biodiversity in areas that have been severely impacted by urban development. The most important and understudied green space is homegardens. Homegardens contribute greatly to the species composition of urban and rural settlements. The aim of this study was to determine to what extent the socioeconomic status of the inhabitants of a rural village influences the plant species composition of the settlement. The settlement of Ganyesa, situated in the Bophirima district in the North West Province, was chosen for the study. Using GIS techniques, a grid was placed over the settlement and plant surveys were done every 500 m. Different land-use types were identified during the completion of the survey, namely; natural areas, fragmented natural areas, fallow fields, road verges, wetlands, home gardens and institutional gardens. A social survey was completed by means of questionnaires in order to determine the socioeconomic status of the owners of the 55 studied homegardens. The national South African census data from 2001 proved to be too unreliable to accurately determine the SES of the residents in Ganyesa. The vegetation composition for all the homegardens was compared with the resident’s socioeconomic status along a socioeconomic gradient, ranging from low, to medium or high. ANCOVA, multiple regressions and basic statistical analyses were performed using all the vegetation and socioeconomic data. Visible correlations occur between the socio-economic status of the homeowners and the plant diversity of their gardens.

Low night temperatures inhibits symbiotic nitrogen fixation and affects the potential for

recovery in a chilling sensitive soybean genotype

M. de Beera, A. Jordaana, P.D.R. van Heerdena,b aSchool of Environmental Sciences and Development, North-West University, Potchefstroom Campus, Potchefstroom, South Africa bSouth African Sugarcane Research Institute, Mount Edgecombe, South Africa

Soybean [Glycine max (L.) Merr.] is sensitive to sub-optimal growth temperatures which leads to changes in metabolism, growth, development and yield. The inhibition of symbiotic nitrogen fixation (SNF) is one of the changes. Symbiotic nitrogen fixation is energy demanding and requires sucrose to be metabolised by sucrose synthase (SS) during respiration in the nodules, while atmospheric nitrogen is fixed by nitrogenase to an export product known as ureides. A study was undertaken to determine the effects of long-term dark chilling on various indicators of nodule carbon and nitrogen metabolism, as well as the recovery of these indicators over a period of 4 weeks following dark chilling. Glasshouse cultivated plants of the chilling sensitive South African soybean genotype PAN809 were exposed to dark chilling (6ºC). During the chilling period neither sucrose synthase activity nor leghemoglobin content were negatively affected. However, ureide content showed a significant decrease of up to 60% compared to control plants, while nitrogenase activity was inhibited by up to 88%. Following dark chilling a period of 2 weeks was required for full recovery, indicating that substantial time is required to restore nitrogen fixation capacity. Morphometric analysis showed an increase in intercellular air spaces within nodules which could lead to an increase in O2 conductance and further aggravate the effects of a high O2 environment on nitrogenase activity.

28

Isolation and identification of a novel anti-diabetic compound from Euclea undulata Thunb.

M.S. Deutschländera, N. Lalla, M. van de Venterb aDepartment of Plant Science, University of Pretoria, Pretoria, South Africa, 0002 bDepartment of Biochemistry and Microbiology, P.O. Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth, South Africa, 6031

Four plant species namely Schkuhria pinnata, Pteronia divaricata, Elaeodendron transvaalense and Euclea undulata, which are traditionally used for the treatment of diabetes by South African traditional healers and herbalists, were investigated for hypoglycaemic activity. Acetone and ethanol plant extracts were prepared and tested in vitro, for glucose utilisation on three cell lines namely: Murine C2C12 myocytes, Chang liver cells and 3T3-L1 preadipocytes. The four plant extracts were further investigated for hypoglycaemic activity by evaluating inhibiting effects on carbohydrate-hydrolysing enzymes alpha-glucosidase and alpha-amylase. In vitro hypoglycaemic analysis revealed that acetone and ethanol plant extracts of S. pinnata, E. undulata and E. transvaalense displayed hypoglycaemic activity in one or more cell lines, whereas, P. divaricata showed no hypoglycaemic activity. S. pinnata indicated significant cytotoxicity in preadipocytes. Glucose uptake of 62.2% was obtained by E. undulata extract in C2C12 myocytes, with 100% cell viability. Alpha-glucosidase and alpha-amylase results indicated that P. divaricata extract inhibited alpha-glucosidase, whereas E. undulata and E. transvaalense extracts inhibited alpha-amylase. Phytochemical studies of the crude acetone extract of the root bark of E. undulata produced a new α-amyrine-3O-ß-(5-hydroxy) ferulic acid compound (1), and three known compounds, betulin (2), lupeol (3) and epicatechin (4). In vitro assays on C2C12 myocytes revealed that (2) (21.4%) and (4) (166.3%) were active in lowering blood glucose levels whereas (1) (IC50 4.79 µg/ml) and to a lesser extent (4) (IC50 5.86 µg/ml) and (3) (IC50 6.27 µg/ml) inhibited alpha-glucosidase. Results indicated that the crude acetone extract of E. undulata does contain compounds that display hypoglycaemic activity.

Investigating the vulnerability of marula stems to fire and bark stripping

C.V. Helm Restoration and Conservation Biology Research Group, School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Private Bag 3 Wits 2050, South Africa

Fire induced stem mortality in savanna trees is usually limited to the smaller stem size classes. However, adult stem mortality does occur in response to fire, especially in savannas with large herbivores. It was investigated whether bark stripping would make marula stems more susceptible to subsequent fire through damage of exposed transport tissues directly caused by the fire. Stems were subjected to fire through a wick burning technique and assessed for survival and resprouting thereafter to determine the minimum stem diameter for survival from fire. For stems found to be resistant to fire, combinations of fire and bark stripping treatments were applied to determine the effect of bark stripping on post fire fate. Marula was found to have a higher allocation to bark at small diameter sizes when compared to other common savanna tree species. It was therefore able to resist stem death after an intense fire above 3 cm in basal stem diameter. The combination of stripping and fire had no effect on post-fire stem mortality. Marulas seem well adapted to bark stripping as bark recovery is quick and the storage of water in the stem is postulated to prevent fires from destroying exposed xylem vessels and killing the stems due to lower heat exchange capacity. Therefore, marula adult stem mortality does not appear to be directly caused by the effect of fire on exposed transport tissues as found by other studies, but rather seems to be

29

induced by the introduction of boring beetles into the soft susceptible wood after bark stripping, weakening the stem and causing eventual stem death and toppling.

Do symbiotic plant microbes play a role in the synthesis of the toxic compounds of

Dichapetalum cymosum?

C.B.S. Hendriksa, J.M.M. Meyera, C.F. van der Merweb aDepartment of Plant Science, University of Pretoria, Pretoria, South Africa bLaboratory for Microscopy and Microanalysis, University of Pretoria, Pretoria, South Africa

Dichapetalum cymosum (poison leaf) is a very common problem plant in southern Africa as

it leads to numerous cases where livestock are poisoned. The poisonous entity of this plant poses a

threat to farmers oblivious to the poisons’ symptoms, antidote, and lethal consequence.

Fluoroacetic acid, which was identified as the poison in D. cymosum might, as speculated, be

produced by the plant, but the microorganisms associated with this plant may play a role in its

production too. By utilising various techniques, the bacteria were isolated and subsequently their

capabilities of synthesising such poisons were determined. The isolated bacteria proved to be

species diverse and, therefore, the focus was concentrated on the isolated Streptomyces spp. Cell-free extracts were prepared to establish the presence of the fluorinase enzyme, but further studies

are required. The detection of glandular lesions led to the closer examination of these undescribed

structures. During examination of the cross sections of glandular lesions, unusually elongated

abaxial epidermis cells with vacuoles containing phenolic-like crystals were observed. With closer

investigation, by utilising transmission electron microscopy, the spongy parenchyma cells directly

above the glandular lesions proved to contain clusters of small, virus-like particles in the

chloroplasts. It was also observed that the grana within these “infected” chloroplasts were disrupted

extensively compared to the lesion-free cross sections. Concurrently, Tapura fischeri was examined for the poisonous entity and an attempt to elucidate the chemical structure, using

chemical techniques, was exploited. It is suggested from preliminary results that symbionts might

play a role in the synthesis of the poisonous entities in the Dichapetalaceae family, but further

investigation is required.

South African plant extracts in combating potentially pathogenic oral microorganisms

C.J. Henley-Smitha, N. Lalla, F. Bothab aDepartment of Plant Sciences, University of Pretoria, 0002, South Africa bDepartment of Community Chemistry, Private Bag 1266, University of Pretoria, 0001, South Africa

Dental plaque is a complex bacterial biofilm community, and under certain circumstances, this complex microbial community can cause major dental diseases such as caries and periodontitis. The quest for natural products, to replace currently used synthetic prepared products for the prevention of dental caries and periodontal disease, is becoming increasingly popular. This study investigated the effects and antimicrobial activity of four plants: Barleria albostellata, Dichrostachys cinerea, Sample 3 (Heteropyxidaceae), and Dodonaea viscosa against Actinomyces

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israelii, Prevotella intermedia, Streptococcus mutans and Candida albicans. Sample 3 exhibited the lowest minimum inhibitory concentrations (MIC’s) ranging from 0.65–3.9 mg.ml-1 against the bacteria. The anti-adherence capabilities of the samples were determined using the cytokine, interleukin-8 (IL-8). Scanning electron microscopy images enabled visual evaluation of the anti-adherence effect. The cytotoxicity of the extracts was also determined. During cytotoxicity and anti-adherence evaluation, it was found that Sample 3 had a fifty percent inhibitory concentration (IC50) of 127.1 µg.ml-1 and had the second best anti-adherence properties reducing IL-8 levels by 84%. B. albostellata and D. viscosa had IC50 values of 56.99 and 66.11 µg.ml-1 and reduced IL-8 levels by 90.5% and 73% respectively. Dichrostachys cinerea was found to be relatively non-toxic with an IC50 value of 231.9 µg.ml-1 which reduced IL-8 levels by 92%. The activity-guided fractionation of Sample 3 for the identification of active compounds was done. Four compounds were isolated and are being investigated. Synergistic effects of the selected samples with essential oils as well as a possible formulation for oral care products are currently being analysed.

Increased nutrient inputs to remnant lowland restiad mires in an agricultural landscape:

Impacts on capillaroid root growth, biomass production and decomposition processes

T. Hodgesa, A. Robertsona, J. Rapsona, L. Schipperb, B. Clarksonc aEcology Group, Institute of Natural Resources, Massey University, Palmerston North, New Zealand bEarth & Ocean Sciences Department, University of Waikato, Hamilton, New Zealand cLandcare Research, Hamilton, New Zealand

Montane restiad sloping fens have formed on poorly drained surfaces and seepages on clay-rich tephras at high altitudes along the axial ranges of the North Island of New Zealand. Similar vegetation communities exist on raised bogs formed on colluvial deposits in the southern lowland plains of New Zealand during the Holocene. Peat formation is thought largely due to the formation of decay resistant capillaroid roots by the restiad Empodisma minus, in response to the low nutrient substrates. We measured biomass pools and short-term decomposition dynamics at a sloping fen and raised bog, to determine the role of litter chemistry, substrate chemistry and hydrology on the short-term decomposition dynamics of above and belowground litter pools. As expected, mass loss of shoot, rhizome and capillaroid root litters was lower in the restiad than graminoid species at each site. Internal mire gradients were not reflected in rates of mass loss at either site. Contrary to expectation we found higher biomass and foliar nutrients and lower secondary carbon compounds levels in the litters of a restiad and graminoid species in the raised bog than fen, with mass losses being significantly higher in the bog site. The source of higher foliar nutrient levels is likely anthropogenic (aerial fertiliser application in surrounding agricultural land; historical mire drainage), stimulating high primary productivity and faster decomposition at the bog site. The long-term implications of these alterations to internal nutrient cycling, capillaroid root growth and carbon sequestration will be explored.

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A review of Pteronia species used in traditional medicine in South Africa

I.M. Hulleya, B.-E. van Wyka, P.M. Tilneya, G.P. Kamatoub, A.M. Viljoenb, S.F. van Vuurenc aDepartment of Botany and Plant Biotechnology, University of Johannesburg, P.O. Box 524, Auckland Park 2006, Johannesburg, South Africa bDepartment of Pharmaceutical Sciences, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa cDepartment of Pharmacy and Pharmacology, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown 2193, Johannesburg, South Africa

Pteronia L. is a genus of 70 species of woody shrublets occurring mainly in southern Africa. Published and unpublished ethnobotanical information exists for nine of the species. The uses of these species in traditional medicine are poorly recorded or have remained scientifically unknown. In addition, some unpublished vernacular names have been recorded during this study. Hutchinson and Phillips revised this genus in 1917 and grouped the species into four sections. The nine ethnobotanically important species were placed in four sections: Incanae (P. incana and P. cinerea), Papillatae (P. lucilliodes and P. divaricata), Ciliatae (P. camphorata, P. stricta, P. onobromoides and P. adenocarpa) and Glabratae (P. succulenta). A study of the leaf anatomy showed the presence of either numerous internal oil glands or a single secretory duct adjacent to the phloem of the vascular tissue of the midrib. Certain species have external secretory and non-secretory trichomes that are present on both surfaces of the leaves. The distribution of trichomes agrees quite well with the existing sectional classification system. The essential oil of selected species were distilled and analysed by gas chromatography-mass spectrometry (GC-MS). Myrcene and sabinene are often the main compounds. Anti-microbial studies give scientific support for most of the recorded medicinal uses. Methanol and dichloromethane extracts and essential oils were more active than aqueous extracts. A review of the ethnobotany and leaf anatomy of the nine species will be presented, together with a summary of the essential oil chemistry and antimicrobial activity of P. onobromoides, P. camphorata, P. divaricata and P. incana.

Lead compounds from traditional medicine, a practical point of view

A.A. Hussein, M. Meyer, N. Lall Department of Plant Science, Faculty of Natural and Agricultural Sciences, University of Pretoria, South Africa

The use of ethnomedical information have contributed to health care worldwide and ethnobotanical-derived plant extracts have been considered as important remedies for humankind throughout history. With the rapid industrialisation rate and the loss of ethnic cultures and customs, some of this information will no doubt disappear. An abundance of ethnomedical information on plant uses can be found in the scientific literature but has not yet been compiled into one user-friendly database. Collection of ethnomedical information remains primarily an academic endeavor of little interest to most industrial groups. However, most drug discovery programs previously considered the random collection of plants as the method of choice to identify new lead compounds. This approach however, requires significantly more financial resources than ethnobotanical based selection. Today, traditional medicine is considered to be one of the most important sources for drug discovery, but needs to be optimised to get the maximum output in order to improve the quality of human life. Many traditionally used plants have been explored during the last few years at the Plant Science Department at Pretoria University, the research results indicative of the high value of indigenous knowledge on traditional medicine. Some of these results will be discussed.

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Pursuing imazapyr herbicide tolerance in sugarcane: screening plants produced in vitro

through somaclonal variation and mutagenesis

A.C. Kocha,b, S. Ramgareeba, S.J. Snymana,b, M.P. Wattb, R.S. Rutherforda aSouth African Sugarcane Research Institute, Private Bag X02, Mount Edgecombe, Durban, 4300, South Africa bSchool of Biological and Conservation Sciences, University of KwaZulu-Natal, Durban, 4300, South Africa

Herbicide tolerance is a highly desirable trait in commercial sugarcane. This study explored a strategy for the production of imazapyr-tolerant sugarcane. A protocol for the production of imazapyr-tolerant sugarcane lines through in vitro somaclonal variation and induced mutagenesis of somatic embryogenic cultures of the N12 sugarcane cultivar was developed. The chemical mutagen ethyl methanesulfonate (EMS) was used to induce a single target-site mutation in the acetolactate synthase gene, and tolerance of regenerated plantlets was tested using the herbicide Arsenal (250 g.l-1 active ingredient imazapyr). The initial work determined the mutagenic (8 mM and 16 mM EMS for 4h) and in vitro screening conditions (LD50 = 0.042 µM, LD90 = 0.08 µM imazapyr in the medium) for 6-10 week-old somatic embryogenic calli, and the screening treatment for acclimatised ex-vitro control plantlets (spraying with Arsenal). As the culture conditions (included 2,4-dichloro-phenoyacetic acid) alone did not cause a significant production of somaclones, the mutagenic agent was deemed essential to increase the chance of producing herbicide tolerant plantlets. The EMS and imazapyr treatments were then applied in combination and calli were exposed to increasing levels (0.042 – 0.16 µM) of imazapyr. Plantlet yield decreased and regeneration time increased with increasing stringency of EMS and imazapyr regimes compared with the untreated control. For all treatments, callus mass, number of green and abnormal (albino and visual chimaeric) plantlets, and biomass of acclimatized plantlets were recorded. Amplified fragment length polymorphism analyses were performed on plants surviving exposure to EMS or imazapyr. Profiles were compared with plants derived from the standard tissue culture protocol and field grown N12 plants to determine how each treatment affected the number of polymorphic bands. At present, putative-tolerant plants, which have been exposed to either EMS or a combination of EMS and imazapyr, are being acclimatised after which they will be sprayed with Arsenal (102 g a.i. ha-1; 0.39 M) to confirm their tolerance.

Assessing the floristic importance of proposed conservation areas in North-West Province in

the context of the western Central Bushveld Bioregion

S. Kurzwega, S.J. Siebertb, S.S. Cilliersa, K. Kellnera aSchool of Environmental Science and Development, North-West University, Private Bag X6001, Potchefstroom 2520 bA.P. Goossens Herbarium, School of Environmental Science and Development, North-West University, Private Bag X6001, Potchefstroom 2520

South Africa is one of the world’s megadiverse countries harbouring over 21 000 plant species with 60% endemism. Much of this rich biodiversity is increasingly under threat due to the development needs of a developing country. As a result South Africa has made a commitment for conservation and the sustainable use of biodiversity by ratifying the Convention on Biological Diversity in 1995. Biodiversity planning has become a key focus area that aims at identifying diversity hotspots and priority areas for conservation within and outside of formally protected areas. These are identified by the quantification of indicator taxa (e.g. rarity and endemism) and their

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distribution patterns. The conservation status in North-West Province is low, with only about 3% of its area set aside for conservation. Proposals have been drafted for park expansion to increase this percentage based on the availability of land and linking existing conservation areas. Thus, the aim of this study was to assess the floristic importance of two proposed high priority conservation areas in the context of the western Central Bushveld Bioregion. Plant species data collected from the two study sites was integrated with existing collection data from the PRECIS database (National Herbarium Pretoria (PRE) Computerized Information System) for the 50 quarter degree grids of the western Central Bushveld Bioregion. The data was subjected to ordination with Primer at different taxonomic levels to demarcate broad floristic patterns, which were correlated with environmental data using ArcView. Important plant taxa were identified and quantified in order to demarcate Important Plant Areas for the western Central Bushveld Bioregion and to determine whether these overlap with the proposed priority conservation areas.

The vegetation ecology of the Seringveld Conservancy, Cullinan, South Africa

L. le Grangea, G.J. Bredenkampb, J.H.J. Schaminéeb aDepartment of Plant Science, University of Pretoria, Pretoria, 0002, South Africa bCentre for Ecosystem Studies, Alterra, Wageningen University and Research Centre, PO Box 47 NL-6700 AA, Wageningen, The Netherlands

The Seringveld Conservancy is situated near Cullinan and the area is characterised by deep sandy soils. Sand mining for the building industry has become a major threat to the biodiversity. The flora of the Conservancy is best described as a gradual ecotone between the grassland and savanna biome. The study aims to describe the vegetation of the Seringveld Conservancy, in terms of plant communities, plant species composition and habitat. The Braun-Blanquet approach was used for sampling and 125 relevés were compiled. The data was captured using TURBOVEG and data analysis followed in JUICE 7.0. A total of 376 species was found in the area. Analysis from JUICE resulted in a TWINSPAN dendogram, synoptic table and two phytosociological tables. The phytosociological tables obtained from JUICE were further ordered using Braun-Blanquet procedures. Ten main plant communities and two sub-communities were identified. Each plant community was described in terms of diagnostic, dominant and constant species as well as the habitat features of the plant community. ArcGIS was used to create various maps further highlighting the uniqueness of the area. A vegetation map indicating the locality of the plant communities was compiled. The combined results of the phytosociological tables as well as the GIS maps indicate that the Seringveld Conservancy is a complex area containing high biodiversity.

The taxonomic value of fruit wall structure in the genus Crotalaria (Fabaceae, tribe

Crotalarieae)

M.M. le Rouxa, B.-E. van Wyka, J.S. Boatwrightb, P.M. Tilneya, A.N. Moteeteea aDepartment of Botany and Plant Biotechnology, University of Johannesburg, P.O. Box 524, Auckland Park 2006, Johannesburg, South Africa bSouth African National Biodiversity Institute, Compton Herbarium, Private Bag x7, Claremont, 7735, Cape Town, South Africa

Crotalaria L. is a large genus of more than 700 species, of which more than 500 are endemic to Africa and Madagascar. The name Crotalaria is derived from the Greek word κροταλου

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(a castanet) because of the rattling sound made by the seeds when the often indehiscent and inflated pods are shaken. Despite the apparent diagnostic importance of the fruit and fruit wall, limited information is available on the anatomy of the pericarp in Crotalaria and related genera. Transverse sections were made of the mature pods of 73 species from 13 genera of the Crotalarieae. Three basic fruit wall types can be distinguished in the tribe: (1) a Crotalaria type (multiple layers of lignified cells); (2) a Listia type (single layer of lignified cells combined with large epicarp cells); (3) a Calobota type (multiple layers of small, thin-walled lignified cells). The Crotalaria type occurs in almost all the genera; the Listia type occurs only in Listia, Lebeckia and Lotononis; the Calobota type is found only in some species of the genus Calobota. Within the genus Crotalaria, considerable variation was encountered and the fruit wall structure seems to have taxonomic value at the species level. Indehiscent fruits typically have the lignified cells arranged in two differently orientated layers. Species also differ in the overall thickness of the wall, the relative proportions of the layers, the degree of lignification and the presence or absence of a hairy endocarp.

Preliminary report on algae and cyanoprokaryota diversity in the Drakensberg

A.A. Levanets, J.C. Taylor, A. Venter, S. Janse van Vuuren, L. van Rensburg School of Environmental Sciences and Development, North-West University, Private Bag X6001, Potchefstroom 2520, South Africa

We studied diversity of algae (desmids and diatoms) and cyanoprokaryta in freshwater and aerophytic biotopes in the Drakensberg (South Africa and Kingdom of Lesotho). Diversity, species composition and distribution of the taxa, their ecological characteristics, level of endemism and perspectives of taxonomical studies are being discussed. Our data revealed a high algal diversity in the Drakensberg and confirmed that the Drakensberg (together with the Cape region, Waterberg, Caprivi Strip, Swaziland, Karoo and Namib deserts) is one of the most diverse algal areas in Southern Africa.

Antioxidant metabolism changes in soybeans (Glycine max) in response to sulphur dioxide

fumigation

S. Lindeque, J.M. Berner, G.H.J. Krüger School of Environmental Sciences and Development, North-West University, Potchefstroom, 2520, South Africa

Exposure to concentrations of air pollutants do not only pose a risk to human health, but due to phytotoxic characteristics also cause injury to agricultural crops. Air pollutants enter the plant mainly through the stomata where after it dissolves in the apoplastic fluids. Damage is done to plant tissue as a result of the formation of reactive oxygen species (ROS). Plants respond to ROS formation by adjusting their metabolism with the intention that minimum of damage will be afflicted by the pollutants. Injury to crops will occur when protective responses are inadequate to metabolise the elevated levels of ROS. In this study we aimed to examine the changes in antioxidant metabolism in soybeans in response to sulphur dioxide fumigation. Two soybean cultivars, LS 6164 and PAN 1666 were used. The plants were fumigated with 0 (control), 25, 75 and 150 ppb SO2 for 7 hours per day. Leaf samples were taken after respectively 2 and 4 weeks. The activities of superoxide dismutase (SOD), peroxidise (POD) and ascorbate peroxidase (APX) were determined. The activities of phenylalanine ammonia-lyase (PAL) and lipoxygenase (LOX)

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were determined to establish the effect of SO2 on secondary metabolite metabolism. Increases in SO2 fumigation levels resulted in changes in the activities of antioxidant enzymes as well as the activities of PAL and LOX. Ethnobotany and pharmacognosy of three Cape herbal plants

H.S. Long, B.-E. van Wyk, P.M. Tilney

Department of Botany and Plant Biotechnology, University of Johannesburg, P.O. Box 524, Auckland Park 2006, South Africa

A review is given of the ethnobotanical uses of three historically important plants that were used in Cape Herbal Medicine. The species are Centella glabrata (persiegras), Olea europaea subsp. africana (olienhout) and Tulbaghia alliacea (wilde-knoffel). A comparison of the morphology and leaf anatomy of the species with their more famous and more widely used relatives, respectively Centella asiatica (pennywort or gotu kola), Olea europaea subsp. europaea (cultivated olive) and Tulbaghia violacea and T. simmleri is discussed. Similarities and differences that can be used for pharmacognostic purposes are highlighted. The chemical difference between Centella glabrata and C. asiatica points to the presence of three major triterpenoid glycosides that are in the process of being isolated and identified. Peltate scales that occur on the leaf surfaces of both subspecies of Olea europaea provide an easy way to identify raw material. Subsp. africana leaf extract was found to be chemically similar to that of subsp. europaea. The main active compound of cultivated olive leaf, the secoiridoid oleuropein, was found in high concentrations in wild olive leaf. Other related compounds, tyrosol and hydroxytyrosol that co-occur with oleuropein were also present in the wild olive leaf extract. The compound verbascoside is present only in the cultivated olive and can be used to distinguish between the two subspecies. Wild olive leaf appears to be a suitable alternative source of raw material for commercial olive leaf extract. Tulbaghia alliacea contains high levels of sulphur compounds that give an even more powerful garlic odour than commercial garlic (Allium sativum). Anatomical comparisons will be made between the Tulbaghia species and the main sulphur compounds will be compared and presented. Antioxidant activity and cytotoxicity of three flavonoids from Athrixia phylicoides ethanol

extract

E.J. Mavundzaa, T.E. Tshikalangea, N. Lalla, F.N. Mudaub, A.A. Husseinc aDepartment of Plant Science, University of Pretoria, Pretoria, 0002, South Africa bCentre for Agro-Food Processing, University of Limpopo, Private Bag X1106, Sovenga, 0727, South Africa cDepartment of Chemistry of Medicinal Plants, National Research Centre, El-Tahrir st., Dokki, Cairo, Egypt

Bioassay-guided fractionation of ethanol extract from aerial parts of Athrixia phylicoides using silica and sephadex column chromatography led to the isolation of four known flavonoids; 5-hydroxy-6,7,8,3’,4’,5’-hexamethoxyflavon-3-ol (1), 3-0-demethyldigicitrin (2), 5,6,7,8,3’,4’-hexamethoxyflavone (3) and Quecertin (4). Due to low yield, no further tests were done on compound 3. Isolated compounds together with crude extract were tested for antioxidant activity using DPPH-scavenging method. The crude extract showed a concentration-dependent radical

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scavenging activity with EC50 value 10.64±0.08 µg.ml-1. Compound 4 was the most potent radical scavenger, exhibiting EC50 value of 1.27±0.25 µg.ml-1, followed by compound 1 and 2 showing 2.74±0.10 and 3.41±0.09 µg.ml-1 respectively. Cytotoxicity of ethanol extract and isolated compounds was determined against Vero cell lines using XTT colorimetric assay. The crude extract showed no or little toxicity on Vero cells at lower concentrations tested exhibiting the IC50 value of 107.8±0.13 µg.ml-1. Compound 4 showed minimal toxicity effect by exhibiting IC50 value of 81.38±0.33 µg.ml-1 as compared to compound 2 (IC50, 28.92±0.12 µg.ml-1) and compound 1 (IC50, 27.91±0.18 µg.ml-1). The results obtained from this study provide a clear rationale for the medicinal uses of Athrixia phylicoides. Arabidopsis thaliana knockout mutants lacking fructose 2,6-bisphosphate have decreased

growth rates under fluctuating environmental conditions

A.J. McCormick, N.J. Kruger Department of Plant Sciences, University of Oxford, South Parks Rd, OX13RB, United Kingdom

The aim of this work was to examine the physiological role of fructose 2,6-bisphosphate (Fru 2,6-P) during photosynthesis, growth and reproduction in Arabidopsis thaliana (L.). Three separate homozygous T-DNA knockout lines of 6-phosphofructo-2-kinase (6-PF-2-K; EC 2.7.1.105)/fructose 2,6-bisphosphatase (F26BPase; EC 3.1.3.46) (F2KP), the bifunctional enzyme responsible for both the synthesis and degradation of Fru 2,6-P, were isolated. In all three F2KP-KO lines Fru 2,6-P metabolism was shown to be absent. Distribution of a 14C label confirmed a significant increase in carbon partitioning to sucrose and a decrease in starch synthesis in F2KP-KO plants. Similarly, during the light period F2KP-KO lines exhibited an increase in sugar accumulation and decreased starch levels at both high light (300 µmol.m-2.s-1) and low light (80 µmol.m-2.s-1). When grown under high or low light conditions no growth phenotype was observed. However, F2KP-KO plants exhibited significantly reduced growth rates (ca. 20%) when grown under fluctuating light (80–300 µmol.m-2.s-1) or temperature (22–10oC) during an 8 h light period or under ambient light in a glasshouse environment. Gas exchange and fluorescence analyses indicated that photosynthetic induction is delayed in F2KP-KO plants, leading to a decrease in growth and fecundity when grown in a variable environment. This work confirms the role of Fru 2,6-P in partitioning of carbon between starch and sucrose in leaves during the photoassimilation period but furthermore demonstrates a competitive growth advantage for fine metabolic regulation by Fru 2,6-P under fluctuating environmental conditions. Sulphur dioxide fumigation leads to increases in antioxidant enzymes and changes in the

photosynthetic capability of canola plants (Brassica napus L.)

M.M. Minnaara, J.M. Bernera, G.H.J. Krügera aSchool of Environmental Sciences and Development, North-West University, Potchefstroom, 2520, South Africa

Environmental stressors create challenges in the efforts of agricultural sectors to achieve sustainability in food production. Ozone (O3), sulphur dioxide (SO2) and nitrogen oxides (NOx) are of the most important air pollutant gases in the atmosphere. There has been a considerable increase in the concentration of air pollutants such as SO2 in the lower atmosphere. This phenomenon can

37

be attributed to increases in anthropogenic activities in industrialised areas of the world. Plants respond to stress conditions by increasing the levels of reactive oxygen species (ROS). In this study the effects of different SO2 levels on the antioxidant metabolism and the photosynthetic capability of canola plants (Brassica napus L.) were determined. Canola plants were grown over a time period of five months in an Open Top Chamber (OTC) system. The canola plants were fumigated with 0, 50, 100 and 200 ppb of SO2 for 8 hours per day. Chlorophyll a fluorescence and photosynthetic gas exchange were routinely measured. Leaf samples were taken on four different occasions to quantify the changes in the activity of the stress enzymes ascorbate peroxidase (APX), guaiacol peroxidase (POD) and superoxide dismutase (SOD). Increases in the activity of APX, POD and SOD were observed in canola plants in accordance with an elevation in the fumigation level of SO2. The chlorophyll a fluorescence data indicated a concomitant decline in PS II function (photosynthetic performance index) of canola plants fumigated at 200 ppb. No significant changes in photosynthetic gas exchange were evident at this level of SO2. Are fleshy fruits of alien shrubs a preferred food resource for avian frugivores in the Cape

Floristic Region?

T.M. Mokotjomelaa,b, C.F. Musila, K.J. Eslerb aSouth African National Biodiversity Institute, Kirstenbosch Research Centre, Private Bag X7, Claremont, 7735, South Africa bDepartment of Conservation Ecology and Entomology, and Centre for Invasion Biology, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa

It has been proposed that alien shrubs with their attractive fruit displays could out-compete native shrubs for the attention of avian frugivores, thereby restricting seed dispersal of native species which is crucial for ecosystem maintenance. This hypothesis was tested by comparing the abundance and duration of avian species visitations and foraging activity in two fleshy-fruited alien shrubs (Solanum mauritianum and Lantana camara) with those of two fleshy-fruited native shrubs (Chrysanthemoides monilifera and Olea africana) at four different study sites (Cape Town, Paarl, Hermanus and Swellendam) in the Cape Floristic Region where these alien and native shrubs co-occur. Tests for significant differences (Generalized Linear Model) in the numbers of birds of different species and size class visiting, foraging and perching on alien and native shrubs during their fruiting stage were based on over 1 000 records compiled from 240 hours of observation at the four study sites. The results showed no significant differences in the total avian species complement visiting native and alien shrubs, but significantly greater numbers of birds of different species and size class visiting, foraging and perching on native than alien shrubs. These differences were apparent at all sites, except Paarl. They were most prominent among small to medium (50-150 g) and large birds (> 150 g) and also apparent among individual avian species visiting the shrubs. Insignificantly different numbers of small birds (>30 g) were observed visiting, foraging and perching on native and alien shrubs. It is concluded that alien shrubs do not restrict seed dispersal of native species since more avian frugivores prefer fruits of indigenous plants, which could be due to their natural adaptation to the local flora. Since local avian frugivores forage both alien and native fruits, they share available avian dispersal services and thus, a potential exists for further spread of alien species. A shorter bird foraging bouts on the alien than indigenous shrubs may suggest that alien fruits have higher energy content than indigenous fruits which is being investigated.

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Taxonomic studies on the genus Dolichos (Phaseoleae, Fabaceae) in South Africa

A.N. Moteetee, B.-E. van Wyk

Department of Botany and Plant Biotechnology, P.O. Box 524, Auckland Park, 2006, Johannesburg, South Africa

Taxonomic studies on the mainly African genus Dolichos are presented. The genus belongs to the tribe Phaseoleae and can be distinguished from the closely related Macrotyloma by the short standard appendages, reticulate pollen grains and purple flowers. It is also closely related to, and often confused with, the two monotypic genera Lablab and Dipogon (previously placed under Dolichos), from which it differs in the characters of the style. Many species of Dolichos have a rootstock which is sometimes large and woody or fibrous and is eaten in some parts of southern Africa. The species can be distinguished from each other mainly by the growth form (scandent, prostrate or erect), shape and size of leaflets and shape of calyx lobes (round versus triangular). In South Africa, the genus is represented by ten species, two of which (D. sericeus and D. trilobus) also extend to Tropical Africa. Diagnostic characters, nomenclature and distribution of these species are briefly discussed.

Antimicrobial and phytochemical evaluation of twelve medicinal plants used by the Venda

People

R.B. Mulaudzi, M.G. Kulkarni, J.F. Finnie, J. van Staden Research Centre for Plant Growth and Development, School of Biological and Conservation Sciences, University of KwaZulu-Natal Pietermaritzburg, Private Bag X01, Scottsville, 3209, South Africa

High demand for the development of new drugs from natural products to counter resistant pathogens has lead to an increase in research to validate bioactivities of plants used in traditional medicine. Twelve plants used in Limpopo province to treat venereal diseases, wounds, colds and fever, were extracted with petroleum ether, dichloromethane (DCM), 80% ethanol (EtOH) and water. The extracts were evaluated for antimicrobial [Gram-positive (Bacillus subtilis and Staphylococcus aureus), Gram-negative (Escherichia coli and Klebsiella pneumoniae) bacteria and a fungus Candida albicans] activities using microdilution techniques. The extracts were also tested for phytochemical composition including phenolics, condensed tannins, gallotannins and flavonoids using spectrophotometric methods. The DCM and EtOH extracts of Bolusanthus specious bark and stem showed good antibacterial activity against Bacillus subtilis, Escherichia coli and Staphylococcus aureus with MIC values ranging from 0.0123 to 0.098 mg.ml-1. The water extracts of Ximenia caffra leaf showed a good activity with a MIC value of 0.049 mg.ml-1 against Staphylococcus aureus. All the extracts showed a broad-spectrum antifungal activity with MIC values ranging from 0.39 to 12.5 mg.ml-1 against Candida albicans. The phytochemical evaluation of the 12 plant species revealed high total phenolic compound in all species (> 8 mgGAE.g-1) except the Aloe chabaudii roots and Adansonia digitata bark which had less than 3 mgGAE.g-1. Variable concentrations were observed for condensed tannins, gallotannins and flavonoids in the same plant species. The observed antimicrobial activity in Bolusanthus specious bark and Ximenia caffra leaves could be due to their high phenolic content.

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Micropropagation of Tulbaghia species

V.N.P. Ngunge, J.F. Finnie, J. van Staden Research Centre for Plant Growth and Development, School of Biological and Conservation Sciences, University of KwaZulu-Natal Pietermaritzburg, Private Bag X01, Scottsville, 3209, South Africa

Tulbaghia (Alliaceae) is a genus of plants with medicinal, ornamental and nutritive values. Different plant parts such as roots, bulbs, leaves and flowers are used in the treatment of a variety of conditions. The bulbs of Tulbaghia violacea are used as a remedy for pulmonary tuberculosis as well as an anthelmintic. Due to the diverse uses of plants in this genus, it is overexploitated and may eventually become threatened with extinction. It is therefore the aim of this study to examine the micropropagation of two species from this genus, with the intention of rapidly propagating them in order to ensure that their availability meets future demand. Seeds of T. violacea and T. ludwigiana were successfully decontaminated using 70% ethanol for 60 sec, followed by 1% benlate for 10 min and 3.5% sodium hypochlorite (NaOCl) with a few drops of Tween 20 for 15 min. The decontaminated seeds were rinsed 3 times with sterile distilled water and germinated on one-tenth strength Murashige and Skoog (MS) medium, without plant growth regulators and sucrose. Roots, leaves and hypocotyls derived from seedlings were cultured on MS medium with different concentrations of napthalene acetic acid (NAA) (ranging from 0 to 1.5 µM) and benzyladenine (BA) (ranging from 0 to 15 µM). Preliminary results indicated that the hypocotyls are more responsive in shoot production. No response was obtained with leaves and roots. The effects of different concentrations of auxins (IAA, IBA and 2,4D) combined with cytokinins (kinetin and zeatin) on the organogenesis of these two species will be evaluated.

Micropropagation of sugarcane (Saccharum spp. hybrids) in vitro: a comparison between

semi-solid and liquid RITA® temporary immersion culture systems with respect to plant

production and genotypic and phenotypic fidelity

P.D. Nkwanyanaa,b, S.J. Snymana,b, M.P. Watta aSchool of Biological and Conservation Sciences, University of KwaZulu-Natal, Durban, 4041, South Africa bSouth African Sugarcane Research Institute (SASRI), Private Bag X02, Mount Edgecombe, Durban, 4300, South Africa

Micropropagation of sugarcane is more efficient than conventional vegetative multiplication. In this study, semi-solid and liquid media (temporary immersion using RITA® vessels) alone or in combination were used to evaluate the micropropagation efficiency of the commercial cultivar N41. Somatic embryos were initiated from immature leaf rolls on liquid or semi-solid (8 g.l-1 agar) medium (MS basal salts and vitamins, 2.7 µM 2,4-dichlorophenoxyacetic acid, 58.4 mM sucrose, 0.5 g.l-1 casein hydrolysate, pH 5.8) for 3-5 weeks at 26 ± 1ºC. Embryo germination proceeded on semi-solid or liquid media (full or half strength MS nutrients, 2.9, 14.6 or 58.4 mM sucrose, 0.5 g.l-1 casein hydrolysate, pH 5.8). Plantlet yield was significantly higher in the RITA® system when compared with the semi-solid regime (18368.0 ± 3617.2 and 2261 ± 289, respectively). However, many plants were hyperhydrated (60.2% ± 3.9 in liquid versus 16.2 ± 3.2 in semi-solid regime). Plantlet survival ranged from 4.4 - 90% 6 months after acclimation, but hyperhydrated plants did not survive. Strategies to alleviate this included increasing intervals between immersion and reducing sucrose and MS concentrations. Subsequently, the most efficient micropropagation protocol was in RITA® vessels with immersion of 1 min every 72 h in ½ MS

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nutrients and 58.4 mM sucrose. Phenotypic integrity of plants from all treatments was investigated by standard agronomic and yield measurements 6 months after field growth. Although stalk mass and population as well as sucrose and fibre content of all in vitro-derived plants were less than the conventionally propagated control, none of the differences were significant. The only significant variation was observed in respect of stalk height, where the control was taller than plants propagated in vitro. Genotypic fidelity of field-grown plants from all regimes was established by amplified fragment length polymorphism (AFLP) analysis and the number of polymorphic bands was low (0.1-2.9%) when compared with the control.

Impact of limestone quarrying on the vegetation of Ewekoro, Nigeria S.O. Oke, G.A.O. Ibhanesebhor Department of Botany, Obafemi Awolowo University, Ile-Ife, Nigeria

Species composition of the vegetation of several sites in a cement manufacturing town, Ewekoro, Nigeria, was studied. The aim was to document the plant species composition (biodiversity) of the quarry sites and its environs, which will provide baseline data for assessing the future impact of limestone quarrying on the vegetation of the area. Limestone excavation in the area has altered the landscape by creating new and varied habitats, namely ponds and spoils heaps, which were not originally in the area. These new habitat types have provided a haven for displaced species. The original vegetation of the area has also been greatly disturbed by agricultural activities. The present vegetation is therefore secondary as the girth sizes of the woody species represent that of juvenile trees. Three distinct vegetation types were identified, gallery forest along water bodies dominated by Alchornea spp, Raphia spp and Elaeis guineensis, spoil heap vegetation dominated by Leucaena leucocephala, Azadirachta indica and Tithonia diversifolia, and lowland secondary grassland vegetation dominated by Anacardium occidentale, Elaeis guineensis, Mangifera indica and Newbouldia laevis. The pond vegetation is dominated by the grass species, Typha australis. The spoil heap vegetation has fewer woody species but higher density than species rich lowland secondary grassland vegetation.

Influence of plant-derived protease inhibitors on the expression of the VP1 antigen from foot-

and-mouth disease virus in tobacco

P. Pillaya, J. Vorstera, K.J. Kunerta, U. Schluterb aDepartment of Plant Science, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0002, South Africa bDepartment of Biochemistry, University of Erlangen-Nurnberg, Staudtstr. 5, Erlangen, 91058, Germany

Plant cell systems can be used as an efficient expression system for recombinant proteins. Protein yield however, is severely limited by endogenous degradation through plant proteases. We investigated the VP1 structural protein from the foot-and-mouth disease virus as a model for plant-based recombinant protein production with the co-expression of an oryzacystatin, a plant-derived cysteine protease inhibitor to enhance production of the VP1 antigenic protein. The VP1 construct was infiltrated into the plant through the method of syringe agro-infiltration. The VP1 protein was then transiently expressed in the cytosol of non-transgenic tobacco plants (N. tabacum) as well as in transgenic tobacco plants expressing the oryzacystatin and co-expressing a maize serine protease

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inhibitor. We are currently using SDS-PAGE analysis to analyse the protein profile and Western blotting to confirm the presence and amount of expression of VP1 in the different types of tobacco plants. First data about the different analyses will be presented.

Nitrogen fertiliser requirements of medicinal plants

G. Prinsloo, J.C. Viljoen, C.P. du Plooy Agricultural Research Council, Roodeplaat Vegetable and Ornamental Plant Institute (VOPI), Private bag x 293, Pretoria, 0001, South Africa

The question of whether medicinal plants can be cultivated to meet rising demand for medicinal plants is a burning matter. Cultivation has been suggested to be a solution to not only meet increased demand for medicinal plants, but also a tool for biodiversity conservation and poverty alleviation. The growing demand for medicinal plants is related to the great cultural significance attached to medicinal plants. The growing demand has not only resulted in increased hazard for overexploitation of wild populations, but also an increased interest in cultivation. The intensive harvesting of medicinal plants due to increased use has in many places resulted in overexploitation and forms a serious threat to biodiversity. This results in acute shortages and price increases for certain plant species. Very little information is available on growing and cultivation of medicinal plants. In this study the effect of nitrogen fertiliser on the yield, chemical composition and antibacterial activity has been determined. Phosphorous and potassium were applied before planting and nitrogen after planting. LAN, ureum and ammonium sulphate were applied at 0 (control), 180, 240, 300 and 360 kg N.ha-1. The trial was harvested twice and the fresh plant material weighed. All the treatments showed significant increases in the fresh mass yield of the plants.

The genus Pelargonium (Geraniaceae) in southern Africa

E. Retief, T.T. Masupa National Herbarium, South African National Biodiversity Institute, Private Bag X101, 0001, Pretoria

Every year garden ‘geraniums’ by the million are being produced by nurserymen for adornment and decoration in homes, offices, streets, public parks and botanic gardens throughout the world. These are mainly derived or bred from the wild species of Pelargonium in southern Africa. Some species are used in the perfume industry, cultivated and distilled for their scent, while others have medicinal properties. Pelargonium species are also used as food plants by several butterfly and moth species (order Lepidoptera). L’Héritier, a French magistrate and botanist, was the first to use the generic name Pelargonium. The genus comprises about 280 species worldwide, with the majority (ca. 230 species) confined to the southern tip of Africa. Its wide range of variation in morphology and habit led to the recognition of various sections by botanists. However, to facilitate the identification of specimens from different parts of southern Africa, it was decided to develop an artificial key to the taxa based on leaf and floral characters, not taking into account life form, stem, pollen, chromosome or pollinator features. Currently sixteen informal ‘groups’ are recognised by using the outline, base, apex and margin characters of the leaf blade. Within the groups the characters of the flower are of importance—inflorescence, 2–many-flowered; colour, patterns of the markings and size of the petals; length of the hypanthium and the number of fertile

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stamens present. The fruit of Pelargonium, a rostrate schizocarp, is of no value as a tool in identifying species, since it is seldom collected. It is the striking beauty of the flowers that catch the eye of the zealous plant collector!

DNA fingerprinting of Plectranthus plants for protection of cultivar registration

L.J. Rice, G.D. Ascough, J.F. Finnie, J. van Staden Research Centre for Plant Growth and Development, School of Biological and Conservation Sciences, University of KwaZulu-Natal Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa

The genus Plectranthus has provided several popular garden and potted house plants in South Africa. Vibrant floral colours and textured leaves contribute to its aesthetic appeal. Breeders have, for a number of years, developed new varieties with larger flowers and more exciting floral shades, ranging from white to blue. Unfortunately, it has become common for nurseries and garden centres to sell these new and improved Plectranthus varieties without permission from the breeders infringing on plant breeders rights. This has left many breeders struggling financially and unable to maintain their breeding programs. DNA fingerprinting techniques, RAPDs and ISSRs, were employed, in a forensic capacity, to determine which Plectranthus varieties were for sale at nurseries and garden centres in the Pietermaritzburg area. This research is directed at developing a simple, cost effective method for the rapid determination of Plectranthus varieties that are protected by registered patents.

Evaluating the functional status of a rehabilitated gold tailings storage facility – a case study

in the Witwatersrand

A.S. Rossouwa, H.J. Annegarna, I.M. Weiersbyeb, D.G. Furnissb aDepartment of Geography, Environmental Management and Energy Studies, University of Johannesburg, P.O. Box 524, Auckland Park, 2006, South Africa bSchool of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Private Bag 3, WITS, 2050, Johannesburg, 2000, South Africa

The Witwatersrand basin is the world’s largest gold deposit, containing hundreds of Tailing Storage Facilities (TSFs). The purpose of TSFs (storing tailings to minimise impacts on the environment) has not been achieved. For mining companies to comply with stringent requirements on mitigation and surface rehabilitation, closure applications should be supported by scientific evidence that the TSF meets biogeophysical and ecological criteria. Landscape Function Analysis (LFA), an indicators-based monitoring technique focusing on the biogeophysical system, has recently been endorsed by Australian regulators to assess mined land rehabilitation effectiveness. A TSF was selected in the central Witwatersrand that is representative of many gold mine TSFs vegetated by similar methods for stabilisation of surfaces. The top, northern and southern slopes of this TSF were evaluated for basic substrate chemistry, vegetation % aerial cover and species composition, and LFA indicators (landscape organisation, nutrient-cycling, infiltration, and stability). LFA relies on regular comparison of rehabilitated sites with natural analogues – which represent ideal endpoints. A nearby natural grassed hill with similar slope steepness was selected as the LFA analogue for broad comparison with the TSF. For the analogue, vegetation aerial cover (90%), surface stability (65%), and nutrient cycling (23%) values were significantly higher than the

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TSF values (52%, 58%, and 19% respectively), with no significance between infiltration (~ 30%). The TSF is covered with a many alien species (51%). Outcomes suggest that the functional status of the TSF is poorer than the natural analogue, however, repeated monitoring of these indicators are required to determine whether the TSF conditions are improving. LFA adds value to the traditional botanical methods of surface assessment as it considers the ecological functioning of the entire system; and has proven to be a useful approach for assessing the functional status of mined lands. LFA is useful to inform authorities in making closure decisions.

Identifying threatened terrestrial ecosystems in South Africa

M. Rougeta, T. Smithb, A. Driverc aDepartment of Plant Science, University of Pretoria, Lynwood Road, Pretoria, 0002, South Africa bSouth African National Biodiversity Institute, Private Bag X101, Pretoria, 0001, South Africa cSouth African National Biodiversity Institute, Private Bag X7, Claremont, 7735, South Africa

Habitat transformation and fragmentation are major causes of species and ecosystem loss. As a result, a large body of research has focused on the identification and conservation of threatened species. Surprisingly, the identification of threatened ecosystems has received much less attention. Here we present a framework for identifying and classifying threatened terrestrial ecosystems. The framework is based on six criteria which have a direct impact on ecosystem function or composition. These are irreversible habitat loss, rate of habitat loss, habitat fragmentation, limited geographic extent and imminent threat, habitat requirement for the persistence of threatened species, and important priority areas identified by systematic provincial conservation planning. An ecosystem can be listed endangered under any of these criteria. We tested and applied the criteria to terrestrial ecosystems in South Africa. A total of 225 threatened ecosystems (of which 53 are critically endangered) were identified, covering less than 10% of South Africa terrestrial surface. Such framework will considerably assist conservation planning and implementation of conservation actions for threatened ecosystems. Indeed, threatened ecosystems are legislated by the Biodiversity Act and current land use practices (e.g. new development on virgin land) are restricted where threatened ecosystems occur.

South African native trees increasingly threatened by diseases

J. Rouxa, S. van der Merweb, E. Malanc, M.W. van Rooyend, M.J. Wingfielda aDST/NRF Centre of Excellence in Tree Health Biotechnology (CTHB), Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0002, South Africa bPO Box 2099, Kuruman, 8460, South Africa cNational Zoological Gardens Biodiversity Conservation Centre, Mokopane, South Africa dDepartment of Plant Sciences, University of Pretoria, Pretoria, South Africa

Reports of unexplained mortality of native trees in South Africa and Namibia have increased

substantially in recent years. In some cases, the mortality has been associated with changes in rainfall patterns and other climate driven factors such as for the deaths of Aloe dichotoma in Namibia and a number of native plants in the Outeniquas. The death of some woody plants, such as Leucospermum spp. and Ocotea bullata in the Western Cape, has been shown to be caused by pathogens such as the introduced Phytophthora cinnamomi and Armillaria spp. However, a number of reports of dying trees, such as those of dying Acacia erioloba and Euphorbia ingens, remain

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unexplained. It is well recognised that interactions between plants, humans, the environment, insects and micro-organisms are complex and difficult to characterise. Pilot studies of declining A. erioloba and E. ingens have revealed a number of undescribed fungal genera, emphasizing the lack of knowledge regarding fungi in Africa. Likewise, apparently undescribed insect species have been found associated with these dying trees. There is clearly an urgent need to increase our understanding of the interacting factors associated with the wide-scale mortality of native South African trees that is occurring in various parts of the country. Solutions, and a chance to save some species that are apparently threatened with extinction will require inter-disciplinary research initiatives and also different approaches to those that have been used to understand tree health problems in the past.

Comparison of secondary metabolite content and antimicrobial activity of four Hypoxis

species used in traditional medicine

N.R. Sathekgea,b, Q. Kritzingera , G. Prinsloob aDepartment of Plant Science, University of Pretoria, Pretoria, 0002, South Africa Agricultural Research Council (VOPI), Private Bag X293 Pretoria, 0001, South Africa

Hypoxis (African potato) is a genus of the family Hypoxidaceae. The rootstocks of Hypoxis species are used in traditional medicine for the treatment of different ailments such as urinary tract infections, prostate cancer, wounds etc. Several visits have been made to the Faraday medicinal market in Johannesburg to check the prices and availability of Hypoxis, however, it was discovered that different Hypoxis species are harvested and sold under the same name i.e. African potato. This is a concern where plant preparations are taken orally and the information regarding the plants being used not correct. This might be dangerous in the event where secondary metabolites of these plants are not the same. The aim of this study is to compare the secondary metabolite content and microbial activity of four Hypoxis species namely, H. acuminata, H. hemerocallidea, H. iridifolia and H. rigidula. Thin layer chromatography and high performance liquid chromatography were used to analyse secondary metabolite content of the plant extracts. Different bioassays were used to determine the antibacterial, antioxidant and cytotoxicity activity of these species. Column chromatography was used to isolate the compounds. Compounds observed on the TLC fingerprints were similar in all four species. There was one compound that was present in H. rigidula and H. acuminata which was absent in H. hemerocallidea and H. iridifolia. The antibacterial activity also showed a similar profile against three microorganisms, namely Escherichia coli, Enterococcus faecalis and Staphylococcus aureus. All four species showed no toxicity when tested in vitro on Vero cells however, the plant extracts seemed to be toxic to cancer cells (U937 cells) in particular H. iridifolia. Hypoxoside was isolated and identified as the purple band on TLC fingerprint. The HPLC results showed major differences in fresh material. After the material was stored, the results showed the same profile in all the species.

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Protective effect of the anti-ozonant, ethylenediurea (EDU), on development and

photosynthesis of Glycine max under ambient and elevated ozone levels in an OTC system

C.C.W. Scheepers, J.M. Berner, G.H.J. Krüger School of Environmental Sciences: Botany, North West University, Potchefstroom, 2520, South Africa

Tropospheric ozone (O3) is one of the most important phytotoxic air pollutants. Due to the growing energy demand and increasing industrial activity, O3 levels are expected to rise in southern Africa. Ozone affects natural vegetation, forests and crops due to the oxidative stress it imposes on biochemical level. Ozone affects photosynthetic capacity, patterns of carbon distribution and leaf senescence. It also promotes foliar injury. These effects are reflected by loss of chlorophyll, change in chlorophyll a fluorescence kinetics and gas exchange parameters. The anti-ozonant, , N-[2-(2-oxo-1-imidazolidinyl) ethyl]-N’-phenylurea (EDU) is known to prevent ozone damage in many plants, which makes it a key research tool in assessing the effects of O3 on plants. A field study was conducted with soybean plants (Glycine max) grown and exposed in an open-top-chamber (OTC) system to controlled different levels of O3. Non-EDU-treated plants were markedly affected by the O3 treatment. The effects of O3 on PSII and PSI function and photosynthetic gas exchange of the treated plants were analysed and interpreted. Apart from visible symptoms and reduced yield induced by elevated O3 levels, the CO2 assimilation rate (A) was reduced by 26%, mainly due to a corresponding 36% decrease in the carboxylation efficiency (CE). Parallel chlorophyll a fluorescence data indicated that a concomitant decrease occurred in the photosynthetic performance index (PIABS), which was mainly due to inhibition of the quantum yield of reduction of end electron acceptors of PSI. The study clearly demonstrated that EDU alleviates the unfavourable effects of O3.

Morphological and anatomical adaptations of Boerhavia L. and Commicarpus Standl. to

survive in arid environments of Namibia

M. Struwiga, A. Jordaanb, S.J. Sieberta, L.R. Tiedtc aA.P. Goossens Herbarium, School of Environmental Science and Development, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa bSchool of Environmental Science and Development, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa cLaboratory for Electron Microscopy, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa

Namibia is the centre of diversity for Boerhavia L. and Commicarpus Standl. in southern Africa and these two genera have the ability to grow on soil rich in gypsum. Namibia is known to be a dry, hot country. This arid environment poses challenges to the survival of species and as a result plants have developed morphological and anatomical adaptations that assist them to survive. The adaptations of the leaves and anthocarps of two endemic Boerhavia species, B. deserticola Codd. and B. hereroensis Heimerl, as well as six Commicarpus species found in Namibia, were investigated using light- and scanning electron microscopy. Both the abaxial and adaxial surfaces of the leaves are covered with multicellular, glandular trichomes that secrete mucilage. The trichome layers are very dense in the two Boerhavia species but less so in the Commicarpus species. These trichomes decrease transpiration and lower the leaf temperature by increase reflection of solar radiation. The Boerhavia species also show Kranz anatomy. The cuticle is thick and impregnated with calcium oxalate crystals. These crystals, tannin and mucilage cells are

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scattered throughout the leaves. The anthocarp of the Boerhavia species has five ribs which are glabrous in B. deserticola but pubescent in B. hereroensis. The anthocarp of the Commicarpus species has ten obscure ribs and large, dark, glands scattered over the surface with very few trichomes. The anthocarp of both genera produces mucilage which might aid in seed dispersal and germination, and they have abundant sclerenchyma for structural support.

Species with potential for Industrial Crops in South Africa

K.M. Swanepoela, W.G. Albertsb aUniversity of Zululand, Coral Str 111, Lynnwoodglen, Pretoria, 0081, South Africa bKarwil Consultancy, PO Box 462, Newlands, Pretoria, 0049, South Africa

The demand for natural products is estimated growing at 25% per year. This includes essential oils, plant extracts, and medicinal plants amongst others. A pressure on natural resources can be prevented if careful sustainable measures are taken in time. Industrial crops are plant species that need processing before utilisation. Species with potential for development as industrial crops in South Africa has been identified and studied. The focus was on medicinal, essential oils, beverages and fibres. Ten species were chosen under each category and a data base was formed. International production, market trends and international standards were documented against the production of South African producers. Advantages and problems have been identified with potential of crop development. This study could assist role players of community projects, agricultural and rural development in the decisions of choosing alternative crops and entrepreneurship for skills development and poverty alleviation. The information from the study can also be applied by small scale and emerging farmers in the feasibility studies of utilisation of natural products as enterprises.

The value of anatomy in pharmacognosy and forensic studies P.M. Tilney, B.-E. van Wyk Department of Botany and Plant Biotechnology, University of Johannesburg, PO Box 524, Auckland Park, 2006, South Africa

Anatomical characters are potentially useful to identify small fragments of commercially important herbal products as well as toxic plants that may be of relevance in forensic investigations. An increasing number of indigenous medicinal plants are being used both in the formal and informal economy so that the positive identification of species and infraspecific taxa has become important. Unfortunately very few of these plants have been studied anatomically. Plants are often the cause of fatalities due to the inappropriate use of herbal medicines or the use of misidentified plants (or sometimes intentionally used in homicide and suicide). The large number of toxic plants in South Africa often leads to stock losses. Anatomical characters can be useful as supportive evidence in forensic work to help identify the plant species in question/ anatomical evidence may often give additional clues as to the identity of the plant when medical diagnosis/ chemical forensic studies turn out to be inconclusive. Anatomical characters of potential diagnostic value will be presented for a selection of herbal medicines and highly toxic plants. Herbal medicines include Agathosma betulina, Aloe ferox, Aspalathus linearis, Catha edulis, Cyclopia intermedia, Elytropappus rhinocerotis, Harpagophytum procumbens, Lippia javanica, Myrothamnus flabellifolius, Pelargonium sidoides, Sceletium tortuosum, Siphonochilus aethiopicus, Sutherlandia

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frutescens and Warburgia salutaris. Poisonous plants discussed will include Nicotiana glauca, Boophone disticha, Nerium oleander, Datura stramonium, Calilepis laureola, Abrus precatorius, Jatropha curcas and Ricinus communis.

Consideration of factors associated with Euphorbia ingens decline in the Limpopo Province of

South Africa

J.A. van der Lindea, D. Sixb, M.J. Wingfielda, J. Rouxa aDepartment of Microbiology and Plant Pathology, Tree Protection Co-operative Programme (TPCP), Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa bDepartment of Ecosystem Sciences, College of Forestry and Conservation, University of Montana, Missoula, Montana, USA

Euphorbia is a large genus including more than 2100 species having a wide global distribution. Several Euphorbia spp. occur in South Africa, of which Euphorbia ingens (naboom) is the largest. During the course of the last 10 years, increasing numbers of E. ingens trees in the Limpopo Province have become diseased, followed by rapid death. Initial studies conducted in 2006 and 2007 recorded various insects and fungi associated with the decline, but a clear cause of disease was not found. Symptoms observed included grayish discoloration, rotting and browning of the succulent branches, white and yellow spots on succulent branches, blue stain of the main woody stems and insect infestation. Various genera of fungi were isolated including several undescribed genera and species. Insects found included genera in the Curculionidae and Pyralidae. A more extensive study was initiated in 2009 in which multiple factors associated with the decline of E. ingens were considered. These factors included symptom and disease development as well as animal damage, elevation, fire damage, grazing levels, rainfall, site aspect, size of each tree, slope, temperature and the vegetation surrounding the trees. Sites in the Limpopo and North West Provinces were monitored in 2009. Damage caused by a moth was found to be devastating in both provinces with over 64 percent incidence. Differences in the occurrence of graying symptoms were observed in the Limpopo and North West Province with 74 and four percent incidence respectively. It is hoped that the knowledge emerging from this extensive study will shed light on the factors responsible for the decline and death of E. ingens in the Limpopo province in the future. The role of cytokinins in seed germination

J. van Stadena, W.A. Stirka, O. Novákb, M. Strnadb aResearch Centre for Plant Growth and Development, School of Biological and Conservation Sciences, University of KwaZulu-Natal Pietermaritzburg, Private Bag X01, Scottsville, 3209, South Africa bLaboratory of Growth Regulators, Palacký University & Institute of Experimental Botany ASCR , Šlechtitelů 11, 783 71, Olomouc, Czech Republic

Endogenous cytokinin levels were monitored during germination and early seedling establishment in monocotyledonous (oats and maize), dicotyledonous (lettuce and lucerne) species and thermoinhibited Tagetes minuta achenes. Endogenous cytokinins were identified using UPLC-ESI-MS/MS. Cis-zeatin types (cZ) were the predominant cytokinins present in dry seeds of lettuce,

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lucerne and oats while dihydrozeatin (DHZ) derivatives and benzyladenine (BA) occurred in the highest concentrations in maize. Following imbibition there was a transient peak in cytokinins prior to radicle emergence in lettuce due to an increase in BA and various topolins, in lucerne due to an increase in cZ- and topolin-forms and in oats due to an increase in trans-zeatin (tZ) forms. Another transient cytokinin peak was detected following radicle emergence due to an increase in cZ-, BA- and topolin-forms in lettuce, cZ- and topolin-forms in lucerne, BA- and isopentenyladenine - (iP) forms in oats and a very large increase in cZ forms and smaller peaks in iP-, tZ- and BA-forms in maize. DHZ-type cytokinins occurred in the highest concentrations in dry T. minuta achenes. Following imbibition at 25 ºC, there was a three-fold increase in the cZ-type cytokinins. Aromatic BA-type cytokinins showed the largest fluctuation, increasing between 26-40 h and dropping to low concentrations by 48 h. The thermoinhibited achenes imbibed at 36 °C had a similar cytokinin profile to the achenes germinated at 25 ºC even though germination was arrested. In view of the high concentrations of cZ isomers and aromatic cytokinins detected in these seeds, it is necessary to re-examine the origin and physiological functions of these cytokinins during germination and seedling establishment.

Freshwater algae (excluding diatoms) of the Sub-Antarctic Marion Island

W. van Stadena, S. Janse van Vuurena, V. Smithb, L. van Rensburga aSchool of Environmental Science, North West University, Private Bag X6001, Potchefstroom, 2520, South Africa bDepartment of Botany & Zoology. University of Stellenbosch, Private Bag X1, Matieland, 7602, South Africa

Marion Island is a unique, isolated natural freshwater ecosystem. Algae play an important role in the island’s freshwater ecosystem, because the aquatic food web is dominated by plankton species. This represents the first taxonomical survey on cyanobacteria and eukaryotic algae (excluding diatoms) present in the freshwaters of Marion Island. The composition of freshwater algal communities, in relation to different types of freshwater bodies, was also studied. A total of 85 algal genera from 7 major divisions were present in the freshwaters of Marion Island. These divisions include Chlorophyta, Chrysophyta, Craspedophyta, Cyanophyta, Euglenophyta, Pyrrophyta and Tribophyta. Lyngbya, Tribonema and Ulothrix were present in all water bodies. Chlorophyta was dominant in terms of diversity, followed by the Cyanophyta. Environmental variables such as pH and PO4-P, and to a lesser extent conductivity and NH4-N influenced the algal composition of the freshwaters of Marion Island. Different types of freshwater bodies are inhabited by specific algal assemblages due to the extreme variability in chemical composition of the freshwaters. The main ecological factors that influence the algal community include enrichment, caused by sea spray, and biotic fertilization. An in-depth study on the algal species composition of the freshwater bodies of Marion Island will provide further insight into the algal community composition and the relationship between algae and water quality.

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A review of ethnobotanical studies in the Cape region of South Africa

B.-E. van Wyk Department of Botany and Plant Biotechnology, University of Johannesburg, P.O. Box 524, Auckland Park, 2006, South Africa

Published and unpublished information on indigenous plant use in the Western, Northern and Eastern Cape Provinces of South Africa will be reviewed. Despite several studies, Khoi-San ethnobotany remains poorly documented and almost every recent survey has revealed important and interesting new records. These include new useful plant species, new uses and new vernacular names. Several examples of such new records from ongoing studies in the Swartland, Cederberg and Hantam regions will be presented. It can be concluded that there is an urgent need to systematically capture indigenous plant use knowledge in the Cape region in order to preserve this rich and unique cultural heritage for future generations.

Interaction of cysteine protease inhibitor mutants with cysteine proteases

S.G. van Wyk, K.J. Kunert, B.J. Vorster, U. Schluter Department of Plant Sciences, Forestry and Agricultural Biotechnology Institute, Faculty of Natural and Agricultural Sciences, University of Pretoria, 0002, South Africa

The importance of specific amino acid residues in the structure of cysteine protease inhibitors is assessed in the project. Non-synonymous amino acid replacements are introduced in the structure of the wild-type inhibitors, with the intended effect of enhancing the inhibitory activity on targeted cysteine proteases. By "inhibitor engineering" these inhibitors might become more potent in their activity against gut cysteine proteases of targeted coleopteran insect pests. Using bioinformatics’ software packages, which predict structures based on the position and changes in the amino acid chain’s tertiary structure, structural changes of the inhibitor by altering specific amino acids have been already determined. However, the actual effect that these alterations will have on activity of targeted cysteine proteases is not yet known. So far, several mutated inhibitor sequences using both the rice and papaya cysteine protease inhibitor sequence have been produced through site-directed mutagenesis of various inhibitor sequence regions. Mutant coding sequences have been cloned into a bacterial expression vector allowing production of a GST-fusion protein in an E. coli system. Applying affinity chromatography using GSH-sepharose to bind the GST fusion and treatment with Factor Xa protease to release the cysteine protease inhibitor from GST, several purified mutated inhibitors have been already produced. These purified inhibitors will be used for in vitro enzymatic assays to determine the influence mutations have on the inhibitory activity.

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Modeling plant cystatins for targeted activity in a multi-trophic context

B.J. Vorstera,c, Ö. Tastan Bishopb, K.J. Kunerta, D. Michaudc aDepartment of Plant Science, University of Pretoria, Pretoria, 0002, South Africa bDepartment of Biochemistry, Microbiology and Biotechnology, Rhodes University, Grahamstown, 6140, South Africa cDépartement de Phytologie, Université Laval, Quebec City (QC) Canada G1V 0A6

Plant cystatins represent an attractive target for the improvement of pest-resistance in transgenic crops intended for human use, given the absence of cysteine proteases in the human gut and the widespread occurrence of these target enzymes among herbivorous Coleoptera. In plants, cystatin are involved in the regulation of several physiological and cellular processes such as organogenesis and storage protein turnover. They also play an important role in the regulation programmed cell death, tolerance to abiotic stresses, and defense against herbivorous and various pathogens. Cystatins act as pseudo-substrates that enter the active site cleft of target cysteine proteases to form tight, reversible complexes that inhibit protease activity. It has been shown that selected mutations of plant cystatins can alter their inhibitory potential against a range of cysteine proteases. Ideally cystatins used in a transgenic approach would be active only against the digestive proteases of target insects while showing little or no activity against the endogenous proteases of the plant or against non-target insects. It has been shown that selected mutations of plant cystatins can alter their inhibitory potential against a range of cysteine proteases. Using a computational biology approach to predict the interaction of candidate cystatins against a range of proteases from plants as well as target and non-target insects we aim to modulate the activity of the cystatin by rational mutation of selected residues in order to achieve targeted activity.

The evaluation of the effect of seed coating on the germination of three perennial grass seed

types in different growth mediums

M. Westcott, K. Kellner, J.M. Berner School of Environmental Sciences and Development, North West University, Potchefstroom, 2520, South Africa

The loss in vegetation cover and abundance is most severe in disturbed and degraded ecosystems. Reseeding of vegetation forms an integral part of rehabilitation in environmental management activities. Seeds are often coated to improve the germination and establishment rates of certain plant species. This study aims to determine the effect of certain coatings on the germination of three perennial grass seed types in different soil growth mediums. The grass types include Cynodon dactylon, Panicum maximum and Anthephora pubescens and the growth mediums, an acidic medium (gold mine’s tailings), an alkaline medium (platinum mine’s tailings), a sandy and clayey soil type. The coated seed types were compared to uncoated (normal) seed of the same species and batch types. The germination of Anthephora pubescens (coated) performed best in more acidic growth mediums, whereas Panicum maximum (coated) germinated best in alkaline soil types. The germination rate of Cynodon dactylon (coated) was the highest in clayey soils, while the uncoated seed of the same species had the highest germination rate in the sandy soils. The effect of the seed coating on the germination metabolism of these seeds was also investigated by measuring the activities of two different germination enzymes after 96 hours of activation of germination, i.e. lipoxygenase (LOX) and peroxidase (POD). The latter experiment was carried out to determine the inhibitory effect of the coatings on the seed germination. After 96 hours LOX- and POD-activity reached a peak in all of the coated seed. From these preliminary results it is evident that the coating

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of seeds does not have any inhibiting effect on LOX and POD activities during germination. Instead, a stimulating effect was observed - confirming that coating of seeds can assist to achieve better germination.

Ethnobotanical survey of plants used for the treatment of constipation within Nkonkobe

Municipality of South Africa

O.A. Wintola, A.J. Afolayan Department of Botany, University of Fort Hare, Alice, 5700, South Africa

Constipation is the commonest gastrointestinal complaint in most developed and poor countries including South Africa. An ethnobotanical survey of plants used by herbalists, traditional healers and rural dwellers for the treatment of constipation was conducted in the Nkonkobe Municipality, Eastern Cape Province of South Africa. The study revealed 10 plant species belonging to 8 families, namely Asphodelaceae, Apiaceae, Asteraceae, Amaryllidaceae, Sapindaceae, Rubiaceae, Polygonaceae and Longaniaceae. Out of these, the members of Asphodelaceae, Apiaceae, Asteraceae and Amaryllidaceae were the most commonly used. The use of decoction of leaves and roots are the most preferred methods of herbal preparations. In all cases, the treatment involved oral administration of the extracts 2 to 3 times per day, for a short period of time, but usually not more than two weeks, or as soon as the condition disappears. Aloe ferox, Boophane disticha, Alepidea amatymbica and Artemisia afra were repeatedly mentioned by the traditional healers as the most widely used for the treatment of constipation in the study area. There was a general belief in the efficacy of the extracts either prepared as infusion, decoction or poultice. Propagation and growth of Boweia volubilis from bulbs

A.M. Zobolo Department of Botany, University of Zululand, Private Bag X1001, Kwadlangezwa 3886, South Africa

Boweia volubilis is an endangered indigenous bulb that is highly valued for its medicinal properties by local communities. With the increasing demand for the bulbs of Boweia volubilis, propagation by rural communities can become a viable option in the conservation of this plant species. For such propagation purposes, bulbs of Boweia volubilis were cut longitudinally into four quarters and sterilized with 1% sodium hypochlorite containing 5 drops of Tween-20 for 20 minutes. The samples were divided into two sizes namely smaller bulbs (20-29 mm in diameter) and bigger bulbs (30-39 mm in diameter) and were dipped in solutions of varying concentrations of NAA and kinetin respectively. The samples were germinated in pots filled with a mixture of river sand and vermiculite (50:50) and placed in the nursery fitted with plastic roof to eliminate rainfall. When seedlings were 10 mm in diameter, they were transplanted into the field. The percentage survival of the larger pieces was significantly higher than that of the smaller ones. Rooting of large bulb quarters was significantly higher (91.8%) than that of smaller ones (55.7%) at 1 mg.l-1 NAA concentration. New bulb formation as influenced by kinetin treatment in small and in large bulb quarters were 65.6% and 98.6% respectively at 1-2 mg.l-1 kinetin. The marketable size in terms of fresh weight (5-54 g.bulb-1) and diameter (20-55 mm) were obtained at 8 months of growth.

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POSTER ABSTRACTS

Abstracts are arranged in alphabetical order according to the presenting author’s surname.

The presenter of the paper is underlined.

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Plant regeneration from seed-derived callus of Arctotis arctotoides (L.F.) O. Hoffm.: A

medicinal herb of the family Asteraceae

A.J. Afolayana, P.O. Adebolab aDepartment of Botany, University of Fort Hare, Alice, 5700, South Africa bPlant Breeding Division, ARC-Vegetable and Ornamental Plant Institute, Pretoria, South Africa

A procedure for in vitro regeneration was developed for Arcotis arctotoides, a plant noted for its several medicinal uses among the rural people of Eastern Cape Province in South Africa. Callus induction was initiated in basal MS salt supplemented with 3% sucrose (w/v) at different concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D). After two weeks, morphogenic responses were evident in cultures and deeply stained light yellow calli were produced. The highest percentage (67.5%) of seed explants inducing callus was obtained on MS medium supplemented with 2.0 mg.1-1 of 2, 4-D in the dark. When the calli were repeatedly sub-cultured in 1/2MS basal medium with a 16-h photoperiod without any hormonal supplement, adventitious roots were produced eight weeks after culture of initiation. The shoots rooted two weeks later. This is the first protocol of in-vitro regeneration described for A. arctotoides and will serve as a foundation for further research on tissue culture, micropropagation and germplasm conservation of this important medicinal plant. The effects of experimental climate warming on the germination, flowering and physiology of

different fynbos species

J.L. Arnoldsa, C.F. Musila, G.H.J. Krügerb aSouth African National Biodiversity Institute, Climate Change & Bio-Adaptation Division, Private Bag X7, Claremont,7735, Cape Town, South Africa bBotany Department, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa

Plants use several environmental inputs in adapting their flowering to a particular season of the year. Information of these environmental controls of flowering is important for production in commercial horticulture and is also significant for assessing whether or not a species is threatened by an environmental change such as global warming. Times of flowering within and among individuals are of biological importance because of its effects on plant reproduction, fitness and survival. Flowering could be affected by several environmental factors such as temperature and photoperiod. It is known that high night temperatures cause floral abortion. The parameters of flowering phenology focus on the onset and duration of flowering and on synchrony amongst individuals as would occur in nature through global warming. However, empirical data are required to validate these predictions. The question of the present investigation is: To what extent would increased temperature interfere with the requirements for germination, flowering and physiology of the fynbos in the Western Cape? These effects are currently being examined by testing the germination of five Proteaceae species, flowering, photochemical performance, growth and reproduction of seven fynbos species, cultivated outdoors beneath 16 banks of infra-red lamps. Lamps in 12 alternate banks 2 were energised to provide a supplementary radiant flux of 60 W.m-2 which elevated average surface temperature by 30C above ambient. The remaining lamp banks were not energised and comprised ambient controls. Warming treatments commenced at the beginning of winter (May). Measurements of flowering intensity were conducted on a weekly basis and measurements of quantum yield of photochemistry were conducted at monthly intervals

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commencing in Spring (October). Progress in this investigation and preliminary results are discussed. Classification of a grassland community along the floodplain of Nylsvlei Nature Reserve,

Limpopo Province, RSA

F.P. Begwa, M.P. Tshisikhawe, M.H. Ligavha-Mbelengwa University of Venda, Private bag X5050, THOHOYANDOU, 0950, South Africa

The grassland community in the floodplain of Nylsvley Nature Reserve was classified hierarchically using the quadrat method of vegetation survey. While sampling, quadrats of 1m x 1m in size were constructed wherein different grass species were sampled, identified and then recorded. After careful sorting and counting of individuals within the quadrats, species frequency and density were determined. Grass species like Hyparrhenia hirta and Cynodon dactylon were found in large quantity when compared to other species found along the floodplain. The species frequency of Hyparrhenia hirta, Perotis pateal, Aristida congesta and Eragrostis pallens were calculated and found to be high. Hyparrhenia hirta had the highest importance value. The grassland community was then classified as Hyparrhenia hirta - Cynodon dactylon. When botany blooms, biodiversity benefits: celebrating botany during the 2010 International

Year of Biodiversity

C.L. Bredenkamp, P. Gozo, E.T. Rampho South African National Biodiversity Institute, Private Bag X101, Pretoria, 0001, South Africa

Established at the Earth Summit in Rio de Janeiro in 1992, the Convention on Biological Diversity (CBD) is an international treaty for the conservation and sustainable use of biodiversity and the equitable sharing of the multiple benefits of biodiversity. The United Nations General Assembly declared that 2010 will be the International Year of Biodiversity (IYB) to help raise awareness of the importance of biodiversity all over the world. CBD partners include governments, the scientific community, international organisations, key economic sectors, educational bodies, media, indigenous communities, park managers and farmers. The goals are to remove the perception that people are disconnected from biodiversity, to raise awareness of the threats of biodiversity loss and the benefits of safeguarding it and to promote a sense of urgency for action to halt the loss of biodiversity, and encourage people to act now. The biomes of South Africa, Lesotho and Swaziland are used as an example to illustrate the status, threats and actions taken to conserve biodiversity in this region. The effect of global climate change on biodiversity is also mentioned, in the light of examples such as Aloe dichotoma Masson in the Richtersveld and Euphorbia caerulescens Haw. from the Noorsveld in the Eastern Cape Province. According to the National Environmental Management: Biodiversity Act No. 10 of 2004, the South African National Biodiversity Institute (SANBI) has the mandate to monitor and report regularly to the Minister on the status of the country’s biodiversity, the conservation status of all listed threatened or protected species and listed ecosystems, as well as the status of listed invasive species. The Institute must also

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assist the Minister and other involved parties with the preparation of a National Biodiversity Framework. Evaluation of the ribosomal RNA intergenic spacer region as a diagnostic marker for

Fusarium circinatum

L.-D. de Weta, M.J. Wingfielda, B.D. Wingfieldb, E.T. Steenkampa aDepartment of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Hillcrest, 0002, South Africa bDepartment of Genetics, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Hillcrest, 0002, South Africa

Fusarium circinatum is the causal agent of pitch cancer, which is a devastating disease of Pinus species world wide. Management and control of this disease is dependent on accurate and timely diagnosis of the pathogen. For this purpose, DNA-based methods employing markers such as translation elongation factor 1-α (TEF), histone H3 and the ribosomal intergenic spacer (IGS) region are commonly used. Of these regions, IGS appears to evolve most rapidly, thus representing an attractive target for generating species specific PCR primers. In fact, two different diagnostic procedures for F. circinatum have been developed using this marker, although neither have been tested widely. The aim of our study was to evaluate whether the targeted portion of the IGS region allows specific identification of the pitch canker pathogen from different geographic regions. To achieve this goal, we amplified and sequenced the entire 2500 base pair region of the IGS for 10 representative isolates of F. circinatum from different areas in the world. For comparative purposes, we also included representatives for each of the biological species related to F. circinatum, as well as F. oxysporum. Analyses of these data revealed that both sets of previously published primers have sequences identical to that of F. circinatum. The sequences for these primer sets were also different from those associated with the IGS sequences of species other than F. circinatum. These data therefore show that the existing IGS PCR-based diagnostic procedures for the pitch canker pathogen are indeed specific for the fungus and should allow unambiguous identification of F. circinatum. The establishment of in vitro screening methods for evaluating sugarcane (Saccharum spp.

hybrids) susceptibility to Ustilago scitaminea H. & P. Sydow and Eldana saccharina Walker

N. Devnaraina,b, S.J. Snymana,b, C. Hunterc, S.A. McFarlaneb, R.S. Rutherfordb aSchool of Biological and Conservation Sciences, University of KwaZulu-Natal, Durban, 4041, South Africa bSouth African Sugarcane Research Institute (SASRI), Private Bag X02, Mount Edgecombe, Durban, 4300, South Africa cSchool of Biochemistry, Genetics, Microbiology and Plant Pathology, University of KwaZulu-Natal, Pietermaritzburg, 3209, South Africa

The fungal disease smut (causal agent: Ustilago scitaminea H. & P. Sydow) and stalk borer eldana (Eldana saccharina Walker) place major constraints on sugarcane agriculture in South

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Africa. Although various methods are being applied to manage smut and eldana, the best approach is the introduction of resistant cultivars. However, conventional field-based screening for pest and disease resistance requires several years. This study evaluates in vitro techniques combined with artificial inoculation as rapid screening methods. Inoculation of sugarcane at two developmental stages was investigated: 3 month old plantlets derived from apical meristems and 8-10 week old embryogenic callus derived from immature leaf rolls. Ustilago scitaminea spores were collected from field-infected sugarcane, surface decontaminated by a 3x wash in 0.5 g.l-1 streptomycin sulphate solution and cultured to generate infective sporidia. Two concentrations of sporidial suspensions (1x106 and 1x109 sporidia.ml-1) were used to inoculate plantlets (0.5 µl with a Hamilton® syringe, applied 1 cm above the apical meristem) and callus (via dipping, soaking and vacuum infiltration). The development of a characteristic smut whip was observed in vitro after 10-12 weeks. Evaluation using callus is underway. Surface decontamination of 5 day old eldana eggs was achieved by exposure to 1% sodium hypochlorite (NaOCl) for 15 min. Feeding bioassays were conducted by placement of first instar larvae on in vitro plantlets and callus. Larval mass and length were recorded after 3 and 2 weeks respectively. Preliminary investigations were conducted on cultivar NCo376 which is susceptible to smut and eldana. Future investigations will be conducted on five ‘test’ cultivars whose identity and associated field resistance rating will remain undisclosed until completion of the experiments. Data subjected to statistical analyses will be used to assess the accuracy of an in vitro approach. Finally, the most suitable screening methods for evaluating sugarcane susceptibility to smut and eldana will be determined.

Comparing urban areas: quantifying urbanisation using a gradient approach

M.J. du Toit, S.S. Cilliers, T.C. de Klerk School of Environmental Sciences and Development, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa

The contemporary world is an urban world, wherein urban agglomerations harbour more than half of the human population on earth. Anthropogenic influences dramatically alter the functioning of ecosystems, especially in and near cities. As a result, urban areas represent complex assemblages of unique vegetation communities. The multitude of influences on cities adds to this complexity and understanding the underlying patterns and processes operating in urban areas become increasingly important in a time where human altered ecosystems are among the least understood of all. The urban-rural gradient approach often used to study these patterns and processes, aims to quantify the existing gradient allowing comparisons of vegetation at different locations, each with diverse human influences. Previous studies were not truly comparative due to differences in measures used to quantify the gradient and a lack of a well-defined definition for urban areas. This study compares the results of testing urbanisation measures in two diverse urban areas, namely Melbourne, Australia (population approximately 3 700 000) and Klerksdorp, South Africa (population approximately 220 000), in order to contribute towards the creation of a standard set of measures to allow comparison of cities on a global scale. Comparative urban ecological research could potentially distinguish globally recurring patterns from more local phenomena. Both studies indicated that urbanisation influences vegetation composition and survival and that urbanisation measures could successfully be used to quantify an urban-rural gradient. However, in both of the urban areas it was apparent that demographic- and physical measures, as well as landscape metrics, should be used to accurately quantify the gradient. The urbanisation measures correlated well to the surveyed vegetation of the urban areas, emphasising their ecological significance and usefulness as indicators of underlying patterns and processes. The current study

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illustrates the feasibility of attempting the development of a global set of standard measures. In a world where urbanisation is one of the main threats to biodiversity loss, understanding the urban environment becomes imperative if not essential in the battle of ensuring a sustainable future. DNA profiling of Persea americana using AFLP markers

B.J. Farrowa,b, G. Fouriea,c, N. van den Berga aForestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0002, South Africa bDepartment of Genetics, University of Pretoria, Pretoria, 0002, South Africa cDepartment of Microbiology and Plant Pathology, University of Pretoria, Pretoria, 0002, South Africa

Avocado (Persea americana) is a commercially important fruit crop largely consumed as a fresh fruit and increasingly used in the cosmetics and food industries for extracts such as avocado oil. This polymorphic species is made up by several botanical varieties, including three economically important races: Mexican, Guatemalan, and West Indian. Cultivars of commercial importance are generally hybrids, produced from parents of different race, and it is therefore a challenge to characterise these cultivars. Morphological characteristics are often influenced by the environment and thus even fruit of the same cultivar may show considerable variance in appearance. Certain potentially important new cultivars resemble the ‘Hass’ cultivar closely, from a morphological point of view. The aim of the study was to develop a genetic profile of these cultivars that will allow them to be distinguished from ‘Hass’, which is the most widely grown cultivar worldwide. The amplified fragment length polymorphism (AFLP) technique was selected to ascertain whether differences between these cultivars could be found. This is a profiling technique that relies on the amplification of specific restriction fragments after digestion of total genomic DNA. DNA was extracted from the avocado fruit using the Dneasy® Plant Mini Kit (Qiagen) and AFLPs were produced using the IRDye™ Fluorescent AFLP® Kit for Large Plant Genome Analysis and several primer sets. LI-COR gels produced specific banding patterns for each cultivar and each primer set. Data analysis was achieved using Quantar™Pro, a program specifically for AFLP dataset analysis. The pollen morphological characterisation of selected species of Prunus using the scanning

electron microscopy

S.A. Gilania, R.A. Qureshia, D. Potterb aDepartment of Plant Sciences, Quaid-I-Azam University, Islamabad, 44000, Pakistan bDepartment of Plant Sciences, University of California, One Shields Avenue Davis CA. 95616

Scanning electron microscopy (SEM) of pollen of 20 different species of Prunus was conducted to find the morphological characterisation. The species were collected fresh from the field and the rest were obtained from the Herbarium of Quaid-I-Azam University, Islamabad and the Herbarium of the University of California, Davis, USA. The SEM analysis was done by taking photographs for the whole grain and the sectioning of the exine patterns (surface topography) along with the measurement of the length and width of the grain (L/W ratio). There is a considerable variation in the size, shape and the exine patterns of the pollen of different species. The shape of the

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pollen varies from triangular-acute-convex to triangular-obtuse-convex also including triangular-obtuse-convex-straight and triangular-obtuse-convex-circular occasionally in few species e.g. Prunus cerasifera has the pollen shape slightly different from the other Prunus species being triangular-obtuse-convex-circular in polar view and elliptic-acuminate-obtuse in the equatorial view. The sculpturing of the exine is mostly striate with exceptions like Prunus cerasifera having reticulate and Prunus padus having striate-scabrate (on the equatorial ridge). Prunus cerasus has striate-scabrate-reticulate sculpturing including the exine and the equatorial ridges. It is concluded that there is considerable variation in the pollen morphological characters and exine patterns among the different Prunus species which acts as a taxonomic tool for the identification of Prunus species.

Isolation and identification of endophytes from avocado roots

J.D. Hakizimanaa,b, M. Gryzenhouta, T.A. Coutinhoa,d, N. van den Berga,c aForestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, 0002, South Africa bDepartment of Plant Science, University of Pretoria, 0002, South Africa cDepartment of Genetics, University of Pretoria, 0002, South Africa dDepartment of Microbiology and Plant Pathology, University of Pretoria, 0002, South Africa

Avocado (Persea americana Mill) originated from Mexico through central America to Colombia and Ecuador. Avocado is produced on a large scale in more than 30 countries around the world and was introduced into South Africa in the last decade of the nineteenth century and is now mainly grown in the eastern part of the country. Phytophthora root rot (PRR), the most hazardous soil factor for avocado, is distributed in all avocado soils, and although it is partially controlled by fungicide injections, it is only a temporary solution. The use of natural and specific endophytes from avocado as biological control strategy is another alternative solution. Endophytes are microorganisms residing in the tissues of living plants while causing no apparent symptoms of disease. There are various potential benefits for the host in mutualistic interactions with endophytic fungi, for example induction of defence metabolites potentially active against pathogens, endophytic secretion of phytohormones, mobilisation of nutrients for the host from the rhizosphere. This study aimed to isolate endophytic fungi from avocado roots and to test their antifungal activity against a serious avocado pathogen Phytophthora cinnamomi. Avocado root samples were collected from healthy, diseased or chemical treated avocado orchards in Tzaneen and Kiepersol. Twenty-six endophytic fungal species were identified using morphological traits and ITS- rDNA, β-tubulin and EF1-α sequence analysis refined the fungal groups. A selection of fungal species was screened in vitro for the ability to inhibit P. cinnamomi growth.

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Nutrient cycling and decomposition processes in New Zealand montane restiad mires:

assessing above and belowground biomass pools along internal and external mire gradients

T. Hodgesa, A. Robertsona, J. Rapsona, L. Schipperb, B. Clarksonc aEcology Group, Institute of Natural Resources, Massey University, Palmerston North, New Zealand bEarth & Ocean Sciences Department, University of Waikato, Hamilton, New Zealand cLandcare Research, Hamilton, New Zealand

Montane restiad sloping fens have formed on poorly drained surfaces and seepages on clay-rich tephras at high altitudes along the axial ranges of the North Island of New Zealand. Peat formation in the fens is thought largely due to the formation of decay resistant capillaroid roots by the restiad Empodisma minus, in response to the low nutrient substrates. We measured community composition and biomass pools along internal mire gradients in conjunction with a study on short-term decomposition dynamics. Further to the main study we examined the belowground productivity of Empodisma minus, comparing rhizome and capillaroid root growth with hydrological, geochemical and chemical parameters of the substrate. Resource allocation within aboveground foliage of sequential age was also examined. Initial results suggest recycling of nutrients from senescing foliage, an important trait in a species that grows in substrates of low nutrient availability. Emerging invasive alien plant survey for prioritisation in Gauteng protected areas, South

Africa

T.P. Jacaa, M.A. Kganyea, L. Venterb aSouth African Biodiversity Institute, Private Bag X101, Pretoria, 0001, South Africa bPlant Propagation and Rehabilitation Technologies cc, P.O. Box 99273, Garsfontein East, 0060, Pretoria, South Africa

South Africa’s natural ecosystems, like those in most parts of the world, are under threat from Invasive Alien Plants (IAPs). IAPs are widely considered as major threat to biodiversity as a direct result of human transformation of natural environments. Protected Areas (PAs) have been profoundly affected by IAPs and the consequences of these plants present a significant challenge for PAs managers to manage natural resources unimpaired for the enjoyment of future generations. Therefore prevention and early detection of IAPs are the principal strategies to successful invasive plants management. This study presents findings of the initial survey of emerging invaders or IAPs for prioritisation in PAs of Gauteng. Emerging invaders are those less established species occurring in small isolated populations, but have certain attributes which, in a suitable habitat, could result in an increased distribution range with accompanying detrimental consequences for our natural ecosystems in the next few decades. Emerging IAP’s were identified in PAs of Gauteng and prioritised for eradication adapting the Australian/New Zealand post-border weed risk assessment method. The rate of spread of high priority species is predicted by studying seed dispersal methods and seed viability of seed collected both from the plant and from soil samples.

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Antifungal activity of Gardenia brighamii leaf extracts

L. Kafuaa, Q. Kritzingera, A.A. Husseinb aDepartment of Plant Science, University of Pretoria, Pretoria, 0002, South Africa bChemistry of Medicinal Plants Department, National Research Centre, Dokki, Cairo, Egypt

Gardenia brighamii is an evergreen shrub that belongs to the Rubiaceae family. It is known for it’s antimicrobial activity, and is used as a remedy for a variety of diseases including malaria, fever, hypertension and ulcers of skin. Certain fungi belonging to the Fusarium genus, including F. verticillioides and F. proliferatum, are known to produce fumonisin mycotoxins, which have toxic effects on plants, animals and possibly humans. The problem of food and feed contamination with mycotoxins is of concern and has received a great deal of attention in developing countries. Furthermore, the use of chemical control of these fungi is expensive and it is neither environmentally safe nor friendly. The poor education background of the farmers often leads to misuse of pesticides. Currently, the antifungal properties of plant extracts are being investigated with the aim of finding alternatives to the use of chemicals. The aim of this study was to investigate the antifungal activity of G. brighamii leaf extracts against five fumonisin producing Fusarium species and to isolate potential active compounds. The antifungal activity of the crude extracts was investigated in vitro using the microtitre dilution method and direct bioassay (TLC plates). The results from these two methods confirm the antifungal properties of this plant. The acetone leaf extract showed a MIC of 3.25 mg.ml-1 and MFC of 6.5 mg.ml-1 for F. verticillioides and F. oxysporum. Methanol and dichloromethane extracts showed higher MIC values for the fungi tested. The TLC plates spotted with the methanolic extract showed good inhibition against F. verticillioides and F. proliferatum. By using glass column chromatography, 42 major fractions were collected and one pure compound was isolated. Structural elucidation is underway. Identification and prioritising invasive alien plants hot spot areas in Gauteng M.A. Kganyea, T.P. Jacaa, L. Venterb aEarly Detection and Evaluation of Invasive Alien Plants, South African National Biodiversity Institute, Private Bag X101, Pretoria, 0001, South Africa bPlant Propagation and Rehabilitation Technologies cc, P.O. Box 99273, Garsfontein East, 0060, Pretoria, South Africa

Understanding the potential distribution ranges of emerging invaders in South Africa will facilitate identification of those emerging invaders with the greatest potential to expand their ranges in southern Africa. This will allow protected area managers to focus action and monitoring efforts on the areas most vulnerable to invasion. Research is needed to understand, monitor, and model parameters that may be favourable to invasions, such as climatic conditions, ecosystem disturbance patterns, and land use changes. Baseline research is needed to determine if a species is “new” to an area and to detect changes in pathways. Scientifically sound information is essential to support detection programs. This study was conducted in Gauteng. Information from the SAPIA database and Environmental Impact Assessment (EIA) data as well as reviewing information on permits issued for introduction of plants in South Africa was combined to create a comprehensive list of invasive alien plants in Gauteng. Information in the new list was verified and/or added to through selective field surveys. The distribution information was mapped using GIS and Vegtech to identify the hotspots and potential distribution areas of alien invasive plant species in Gauteng. Even though some results are still pending, this study is the beginning of the development of a scientifically

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sound information database for the early detection and rapid response of alien invasive plant species. Did the dominant plant species of valley floras change as a result of the 2005 earthquake in

Kashmir (with emphasis on the Neelum and Jhelum Valleys)?

R. Khanuma, A.S. Mumtaza, S. Ahmedb aQuiad I Azam University Islamabad, Pakistan bPakistan Museum of Natural History, Garden Avenue, Shakarparian, Islamabad, Pakistan

The earthquake during 2005 severely damaged most areas of Kashmir, especially the Jehlum and Neelum valleys. This study was undertaken to asses the status of vegetation after the earthquake, as well as the differences in winter flora of both valleys. A phytosociological study was undertaken to determine the Importance Values (IV) of species. In each valley 20 quadrants of 10x10 m were laid randomly to record the frequency, density and cover of plant species to obtain IV. In Neelum valley a total of 20 plant species were recorded. In the tree layer the dominant species recorded were Pinus roxburghii and P. wallichiana (IV 68.24, 42.16). Debregeasia saeneb and Dicliptera bupleuroides were dominant shrubs, while Mentha rolyeana and Aristida cyanantha with IV 53.26 and 26.27 were dominant herbs. During similar studies carried out in Jhelum valley, 15 plant species were observed. The dominant trees were Olea furruginea, Populus nigra and Pinus roxburghii. Dominant shrubs were Sarcococca saligna, Skimmea laureola and Justicia peploides. Fragaria nubicola and Aristida sp. were the dominant herbs found in this valley. The results showed that differences were observed in all the strata, i.e. trees, shrubs and herbs. Floristic diversity and phytogeography of the proposed Heritage Park in North-West

Province, South Africa

S. Kurzwega, S.J. Siebertb, S.S. Cilliersa, K. Kellnera aSchool of Environmental Science and Development, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa bA.P. Goossens Herbarium, School of Environmental Science and Development, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa

The Heritage Park project is a interdisciplinary approach towards the establishment of a large wildlife reserve. Key objectives of the overall project are to contribute significantly to conservation and socio-economic development in the underdeveloped and poor northern parts of North-West Province. Various subprojects have been identified to study the feasibility and potential of linking Pilanesberg National Park and Madikwe Game Reserve into a megareserve via a corridor. The biodiversity research includes a detailed survey of the diversity and distribution patterns of the Heritage Park flora. Objectives of the study are to quantify the presence of floristically important taxa (e.g. endemic, threatened, and problem plants) and demarcate Important Plant Areas. This will form the basis for assessing the conservation status and priority of the Heritage Park in the context of the western Central Bushveld Bioregion. Plant species data collected in the field was integrated with existing collection data from the PRECIS database (National Herbarium Pretoria (PRE) Computerized Information System) according to the quarter degree grid approach. Principle Component Analysis ordination was used to analyse the data, which showed a clear grouping of

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species on family and genus level of the surveyed grids. A total of 877 plant species has been identified so far, including 48 South African endemic, 5 Red Data List, 6 protected tree and 118 problematic taxa. The findings will be combined into a sustainable development framework for the establishment of the Heritage Park. In future studies plant distribution data will be digitised for use in spatial modeling to systematically plan for the protected area and tourism infrastructure development. Plant communities of the area leased for mining purposes by Impala Platinum, Rustenburg

A.J.H. Lamprechta, S.S. Cilliersa, A.R. Götzeb aSchool of Environmental Science and Development, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa bEnvironmental Research Consulting, P.O. Box 20640, Noordbrug, 2522, Potchefstroom, South Africa

Systematic conservation planning provides a useful tool for land-use planning and impact assessment, particularly in the mining industry. A study was therefore done to provide sufficient biodiversity information for the establishment of a conservation plan. The major objective of this study is to collect data of areas with high plant diversity or endemism. This will then be integrated into the conservation plan with the intent to guide Impala Platinum in its future planning of land use practices. The licensed mining area, in the vicinity of Rustenburg, covers 29334 ha which includes fourteen operational shafts. The area was stratified into three main categories based on landscape types namely: norite koppies, thornveld and rehabilitated areas. Areas of homogenous plant growth were identified in each category by visual observations and the use of aerial photography. The Braun Blanquet approach was used to sample 140 relevés, which were classified into plant communities. Additional software packages were used for capture, processing and presentation of phytosociological data (TURBOVEG) as well as a visual editor for phytosociological tables (MEGATAB). Ordinations were subsequently performed to confirm the communities. This was achieved by using a multivariate analyses computer programme called CANOCO. Six, three and four communities were identified respectively in the norite koppies, rehabilitated areas and thornveld. Specific environmental factors that influence community structure and composition in the norite koppies were found to be aspect and percentage of soil surface rockiness. The soil type proved to be the major determining factor for community structure and composition in the thornveld areas.

Plant diversity in urban domestic gardens along a socioeconomic gradient in the Tlokwe

Municipal area, North-West Province

C.S. Lubbe, S.J. Siebert, S.S. Cilliers School of Environmental Sciences and Development, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa

The value of domestic gardens in urban areas are increasingly realised in an era of urbanisation that negatively impacts on native biodiversity. It provides a valuable resource for natural wildlife and also presents the urban public with opportunities to conserve biodiversity and

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maintain provision of ecosystem services. Including cultural and socioeconomic variables into urban ecological studies, with the use of the gradient approach, can greatly improve the predictive ability of results and aid ecologically sensible management and planning in the urban environment. The plant diversity along a quantified socioeconomic gradient was determined with the use of spatial statistics and ordinations. The steep socioeconomic status (SES) gradient in the study area is the result of high social and cultural heterogeneity and it can be described as high in the eastern and low in the western parts of Tlokwe. Gardens have shown very high gamma-diversity (nearly 850 species), suggesting high species turn-over (beta-diversity). The so-called “luxury concept” was also very clear: gardens in areas of higher SES sustained a much higher plant species richness than its counterparts in areas of lower SES. Also apparent along the gradient is the negative relationship between cultivation of utilitarian plants and SES, indicating the importance of gardens for livelihoods in poorer parts of the community. Through gardening and urban agriculture, urban inhabitants can improve some of the many pressing social issues (health, unemployment and poverty), and prevent degradation and native biodiversity loss via cultivation. A critical assessment of plant resource utilisation and park expansion in North-West

M.M. Magodieloa, S.J. Siebertb, S.S. Cilliersb, F.P. Retiefb a Biology Department, North-West University, Mafikeng Campus, Mafikeng, 2745, South Africa b School of Environmental Science and Development, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa

In recent years many new park establishment and park expansion initiatives have been launched in North-West with a view to expand the existing conservation footprint. An unavoidable implication of expanding the conservation status of land is the limitations such expansion places on access to resources, such as water, fuel, heritage, etc. The latter issues become even more serious and complex when dealing with tribal communities, since ownership of resources are shared. The aim of this study is to explore what implications park expansion has on access to resources, with particular emphasis on useful plants as an indicator. A checklist of potentially useful plants was compiled for the proposed Heritage Park and surrounding areas based on varying sampling methods. Distribution data was spatially arranged according to Quarter Degree Grids (QDGs). To confirm or reject the people’s claims towards a rich resource base, the results of the useful plant assessment were calculated and subjected to spatial statistics using kriging method to map broad patterns of distributions. Mapping units are grids comprising 50 QDGs (225 km2 each). For each of these grids, the number of useful plants found was calculated under different use categories. This allowed for the calculation of α-diversity for comparative purposes and to provide an indication of the value of specific areas to the local people. Ordinations of data will be conducted using Non-metric Multidimensional Scaling to investigate links between useful plant diversity and human population density/distance from settlements. Surveys were conducted to assess the needs and views of the local community during the development of the Heritage Park. Future assessment will determine the degree to which indigenous knowledge systems are infused and imbedded within the park expansion initiative.

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Sequencing the avocado transcriptome

W. Mahomeda,b, A.A. Myburga,b, N. van den Berga,b aForestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0002, South Africa bDepartment of Genetics, University of Pretoria, Pretoria, 0002, South Africa

Avocados are grown commercially in almost 50 countries, with the South African avocado industry making an important contribution to the world’s avocado supply. In 2007 the total South African avocado production was 65 000 tonnes and the gross value R226 million making the country one of the world’s largest exporters. One of the most serious threats to the avocado industry is Phytophthora cinnamomi. The pathogen infects the plant via the feeder roots causing Phytophthora root rot (PRR) and leads to the death of the plant within 3 years. The aim of the study was to identify genes related in tolerance against PRR and aid in the transcriptome assembly of avocado roots. To achieve this, 454 pyrosequencing of pre-infected and post-infected, tolerant R0.09 avocado feeder root cDNA libraries was done, in order to elucidate genes involved in the defence response to P. cinnamomi. A total of 2 Mb of data was produced using a single lane on the GS-FLX platform; this generated approximately 10 000 reads from which 370 contigs were constructed using the Newbler assembly program. Further characterisation of the sequence data was done using the CAS program and the NCBI database. Approximately 20 putative defence related genes have been identified and will be further analyzed and quantified. This study is the first step in elucidating the avocado transcriptome as well as host-specific defence responses. Tree layer species composition of the Nylsvley Nature Reserve woodland community in

Limpopo Province, South Africa

S.P. Mashile, M.P. Tshisikhawe, M.H. Ligavha-Mbelengwa University of Venda, Private bag X5050, Thohoyandou, 0950, South Africa

A Point-Centered-Quarter (PCQ) sampling method was used on 35 sampling points to determine importance value (IV) on plants species found in one of the woodlands of Nysvley Nature Reserve. From the 35 sampling points twelve plant species were found with their importance value as follows: Burkea africana (89.7), Terminalia sericea (75.9), Dichrostachys cinerea (52.1), Peltophorum africanum (19.9), Ochna pulcra (18.7), Dombeya rotundifolia (14.6), Grewia flavescens (8.8), Acacia karroo (4.6), Ziziphus mucronata (2.96), Combretum molle (2.93), Lannea discolor (5.27) and Securidaca longependiculata (4.2). None of these species are vulnerable or endangered. However B. africana and T. sericea with their highest importance values are, therefore, the cornerstone of the woodland vegetation sampled.

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Elucidation of defence responses induced by aphid saliva

L. Mohase, B.M. Taiwe Department of Plant Sciences, Faculty of Natural and Agricultural Sciences, University of the Free State, P.O. Box 339, Bloemfontein, 9301, South Africa

The use of biotic elicitors in plant disease management has a potential of activating mechanisms of plant resistance, simultaneously increasing host resistance to pests. In pursuit of the eliciting potential in the Russian wheat aphid-wheat (Diuraphis noxia-Triticum aestivum) interaction, salivary material of the Russian wheat aphid (biotypes 1 and 2) was collected from artificial feeding chambers. The crude salivary material was intercellularly injected into different wheat cultivars and induced defence responses determined at different times after treatment. The crude salivary material of the two aphid biotypes differentially induced defence responses in the different wheat cultivars used. Salivary material of the biotype 2 aphid stimulated the highest degree of induction of some of the defence responses investigated. The level of induced activity varied among the defence responses studied and induction of peroxidase activity was the strongest in all treatments. Partial fractionation of the salivary material yielded fractions that differentially induced defence responses in the wheat cultivars used. The project further determines the nature of the elicitor-active fractions. A comparative floristic analysis of peri-urban and rural homegardens in North-West, South

Africa

L.Y. Molebatsia, S.J. Sieberta, S.S. Cilliersb, M. Struwiga, A. Krugerc aA.P. Goossens Herbarium, School of Environmental Sciences and Development, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa bSchool of Environmental Sciences and Development, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa cAfrican Unit for Transdiciplinary Health Research, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa

The Tswana tshimo (homegarden) is an Indigenous Knowledge System. However, there is a general believe that gardens of indigenous cultures are spontaneous and disorganised. This study considers this by comparing peri-urban and traditional rural homegardens in North-West to (1) assess the useful-plant diversity, (2) determine the origin of the species (alien or indigenous), (3) examine the different use categories, and (4) document the positions of plants within indigenous gardening systems. We conducted a survey of 61 homegardens from rural and 51 from peri-urban areas in North-West. A total of 183 useful plants species belonging to the 66 plant families were recorded, comprising 64 medicinal, 80 food, 23 shade, and 16 hedge plants. Few of these useful plant species (26%) are indigenous (semi-wild domesticates), while the majority (74%) are aliens (naturalised and cultivated exotics). The five most often cultivated plant species (50-70% frequency) were Prunus persica, Schinus molle, Ligustrum lucidum, Zea mays and Vitis vinifera. A comparison between rural and peri-urban gardens revealed that rural gardens have a higher mean species richness (51 compared to 39), and 54% of the gamma diversity are alien in contrast to the 67% of peri-urban gardens. Nearly 63% of the plants from the peri-urban homesteads were cultivated, whereas 46% of the species from the rural gardens occur naturally. No significant difference was evident with regard to different use categories. Homegarden floras are collectively planted and positioned according to cultural practices passed down generations, resulting in a

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common layout plan which is repeated in the gardens of rural areas, but is absent from the peri-urban areas. Establishment of Artemisia sp. plant cell suspension cultures

M.E. Nemutanzhelaa, B.G. Cramptonb, D. Mancamaa aCSIR Biosciences, P.O.Box 395, Pretoria, 0001, South Africa bAgricultural Sciences Building, Lunnon Rd, University of Pretoria, Pretoria, 0002, South Africa

Malaria continues to pose major health threat to Sub-Saharan Africa. The sesquiterpene lactone artemisinin produced in the plant Artemisia annua has shown to be effective against quinoline resistant malaria strains. In an effort to improve large scale production of this compound in plant cell systems, we undertook to establish plant cell suspension cultures of Artemisia annua for production of artemisinin. We simultaneously developed a protocol for producing Artemisia afra cell suspension culture. Artemisia afra, an indigenous African plant, lacks the key enzyme to convert artemisnic acid to artemisinin. Future work will involve elicitation of artemisinin and its precursors in cell suspension cultures, and potential manipulation of A. afra cell suspension cultures to produce artemisinin. A micropropagation protocol for Siphonochilus aethiopicus, an endangered South African

medicinal plant

G.L. Ngwenyaa , N. Moodleya, M.E. Nemutanzhelaa, B.G. Cramptonb aCSIR-Biosciences, P.O. Box 395, Pretoria, 0001, South Africa bAgricultural Science Building, Lunnon Road, University of Pretoria, Pretoria, 0002, South Africa

Siphonochilus aethiopicus, also known as wild ginger, is an indigenous plant to South Africa widely known for its medicinal properties. However it has become endangered due to over harvesting. Micropropagation of plants in vitro was developed in order to bring back the species from the verge of extinction. To address this, a combination of parameters which included callus induction of rhizomes, corms and leaf bases as explants, in various media compositions, and a plant regeneration frequency formed the basis of evaluation. In this presentation we report that plant regeneration was achieved via somatic embryogenesis and organogenesis depending on the explant used. However, the rate of callus formation varied dramatically amongst the cultured explants.

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Antinociceptive and anti-inflammatory investigation of Heteromorpha arborescens (Apiaceae)

in animal experimental models

M. Nkomoa, E.J. Ndebiab, B.N. Nkeh-Chungagb, L. Kambizia, J.E. Iputob a Botany Department, Faculty of Health Sciences, Walter Sisulu University, P.O. Box 1, Mthatha, 5117, South Africa b Department of Physiology, Faculty of Health Sciences, Walter Sisulu University, P.O. Box 1, Mthatha, 5117, South Africa

Heteromorpha arborescens (commonly known as the parsley tree) belongs to the family Apiaceae. One of its uses in the Eastern Cape province of South Africa is to treat abdominal pains. The therapeutic effects of methanolic and aqueous root extracts of H. arborescens were investigated on experimental models of pain and inflammation induced in rodents. The antinociceptive activity was evaluated using hot-plate, abdominal constriction, formalin and inflammatory pain. The anti-inflammatory properties were assessed using albumin and carageenan induced inflammation. The extracts were administered orally at the test doses of 150 and 200 mg.kg-1 prior the above mentioned assays. Both extracts produced significant (P<0.05, P<0.01) inhibition on thermal nociception induced by hot plate. On chemical nociception induced by intraperitoneal acetic acid and subplantar formalin injection, both extracts decreased significantly (P<0.05, P<0.01) independent of the dosage the number of writhing episodes and the licking time. Treatment with the extracts in the same doses produced a significant (P<0.05, P<0.01) analgesia effect on inflammatory pain induced by CFA. Concerning anti-inflammatory investigation, both extracts produced a significant (P<0.05, P<0.01) reduction of edema induced by albumin and carrageenan. These results suggest that both extracts of H. arborescens may act by the reduction or inhibition of the mediators of inflammation. These findings seem to justify the use of the plant in traditional medicine in the management of pain and inflammation related diseases. Efficacy of selected plant extracts against fungal pathogens of onion

H.B. Papenfus, Q. Kritzinger Department of Plant Science, Faculty of Natural Agriculture and Sciences, University of Pretoria, Pretoria, South Africa

Fungal diseases may cause 75-100% onion crop losses per year. Treatment of the fungal infections depends on the prophylactic application of conventional fungicides which is labour intensive and expensive. They also pose detrimental effects to the environment and may cause cancer in humans when exposed to these fungicides. Plant extracts used as a bio-control agent has shown comparable activity to those of fungicides against fungal and bacterial diseases on crops. Leaf extracts of Azadirachta indica (neem), Lavandula angustifolia (english lavender), Cucumis metuliferus (wild cucumber), Lippia javanica (fever tree) and Capsicum frutescens (red chili) were evaluated against three common onion pathogens namely Rhizoctonia solani, Colletotrichum gloeosporioides and Fusarium oxysporum in vitro. Acetone leaf extracts of L. javanica, L. angustifolia and A. indica showed significant antifungal activity at 2.5 and 5.0 mg.ml-1 against all three fungi. All the extracts of C. frutescens showed antifungal activity against C. gloeosporioides. Extracts of C. metuliferus had some activity against the C. gloeosporioides and F. oxysporum but not comparable to the activity of the other extracts. Antifungal activity of L. javanica and L. angustifolia correlates well with the activity shown in the direct bioassay on TLC plates. There were three compounds (medium polarity) within the L. angustifolia extract and two compounds

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(polar) within the L. javanica extract which inhibited the growth of all the fungi. Seed treatment tests, in R. solani inoculated soil, indicated higher seedling survival rate and average seedling mass when the seeds were treated with A. indica extract. The implementation of the selected plant extracts as a bio-control agent will reduce production costs. Creating markets for ecosystem services

M. Rougeta, J. Blignautb, B. Egohc aDepartment of Plant Science, University of Pretoria, Lynwood Road, Pretoria, 0002, South Africa bBeatus, Jabenzi, ASSET Research, Department of Economics, University of Pretoria, Lynwood Road, Pretoria, 0002, South Africa cNatural Resources and the Environment, CSIR, Stellenbosch, 7600, South Africa

We conducted a partial sectoral analysis of the market for ecosystem goods and services in South Africa. We mapped the areas of high ecosystem productivity for carbon sequestration, surface water supply, water flow regulation and soil retention. We overlaid these areas with poverty nodes and identified geographic priority areas for developing markets for ecosystem goods and services. We identified large parts of the Eastern Cape, KwaZulu-Natal, Mpumalanga and the Limpopo Province as priority areas where ecosystem productivity is high and poverty rife. The potential market size is considerable. However, the most challenging component is not to prove the economic value of this market but it is to create the appropriate institutions to develop such market. Diverse communities of the Botryosphaeriaceae infect native trees in Southern Africa

B. Slippersa, J. Rouxb, D. Begoudeb, J. Mehlb, J.A. van der Lindeb, D. Pavlicb, F. van der Waltb, H. Malemeb, B. Hinzeb, G. Maraisb, B.D. Wingfielda, M.J. Wingfielda,b aDepartment of Genetics, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0002, South Africa bDepartment of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0002, South Africa

The Botryosphaeriaceae is a well-known fungal family that has been studied for more than 150 years. Many species in this group are important pathogens of trees globally. In southern Africa only ten species were known a decade ago, mostly on non-native hosts. During the past decade surveys on native trees in this region, using modern molecular tools combined with traditional morphological species characterisation, have revealed a staggering diversity of species in this fungal family. Studies on Acacia spp., Terminalia spp., Pterocarpus angolensis, Sclerocarya birrea, Syzygium cordatum and a number of species in the Proteaceae revealed the presence of at least 40 species in the Botryosphaeriaceae, more than 25 of which is thought to be new to science. Many of these species overlap in host distribution on the native tree genera, as well as on non-native agricultural and forestry trees. These results illustrate just how under-explored the fungal diversity of southern Africa is, even in important pathogen groups. This is especially concerning given increasing reports of native tree die-back in southern Africa, and the frequency with which Botryosphaeriaceae are linked to these diseases. This is not entirely unexpected, because the impact of pathogens in the Botryosphaeriaceae has been predicted to increase due to stress on trees caused by climate change.

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Anthocarp structure as a diagnostic character for Boerhavia L. and Commicarpus Standl.

species in southern Africa

M. Struwiga, S.J. Sieberta, A. Jordaanb, P.M. Burgoynec,d aAP Goossens Herbarium, School of Environmental Science and Development, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa bSchool of Environmental Science and Development, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa cNational Herbarium, South African National Biodiversity Institute, Private Bag X101, Pretoria, 0001, South Africa dResearch Fellow, Department of Environmental Sciences, College of Agriculture and Environmental Sciences, UNISA, Private Bag X6, Florida, 1710, South Africa

An anthocarp is defined as a structure comprising a fruit enclosed in a persistent perianth. Anthocarps are characteristic of the Nyctaginaceae. They differ in structure between genera, as the side walls may bear sticky glands or warts that produce mucilage, or have wings that may expand into wing-like folds. The anthocarp is therefore used to distinguish between taxa and most genera can be recognised based on the fruit structure alone. In southern Africa, Commicarpus and Boerhavia are two genera of the Nyctaginaceae that are often confused with one another, although they differ in growth habit, the shape of the perianth and especially the anthocarps. Anthocarps of Boerhavia are clavate or elliptic-clavate with 3-5 ribs or wings which can either be glandular or glabrous. Anthocarps of Commicarpus are cylindrical or fusiform with 10 obscure ribs and large, dark, mucilaginous glands scattered over the surface. Anthocarp shape, size, topography and indumentum are significant morphological characters that can be used to distinguish between the species of other genera in the Nyctaginaceae such as Colignonia and Mirabilis. The taxonomical value of anthocarp structure was investigated for Boerhavia and Commicarpus. Observations of the anthocarp structure of Boerhavia and Commicarpus show that each has its own unique arrangements of ribs, wings and mucilaginous glands, and these characters may therefore be applied to distinguish between the species. SAAB bursar

Seed bank status and dynamics of Acacia saligna at two sites in the Western Cape, South

Africa

M. Strydoma, K.J. Eslera, A.R. Woodb aDepartment of Conservation Ecology and Entomology, Stellenbosch University, Matieland, 7602, South Africa bARC-Plant Protection Research Institute, Private Bag X6006, Hilton, 3245, South Africa

Acacia saligna is the most damaging invasive species in the coastal lowlands of the south-western Cape. The gall rust fungus, Uromycladium tepperianum, has been highly successful as a biological control agent for A. saligna populations in South Africa and has effectively reduced the density, canopy cover and seed production of the tree. However, there are still concerns about the soil-stored seed bank and knowledge of seed bank status and dynamics is crucial for effective management. The study evaluated the effectiveness of two different sampling methods in assessing the status of the seed bank, how the seed bank of A. saligna at two different sites varies over time and how these findings compare to findings of other seed bank studies of A. saligna across southern Africa. Even with the reduction in seed production caused by biological control, numbers of seeds

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in the soil seed bank are high enough to maintain high levels of recruitment after management or natural disturbances. Both sampling methods (grid and random sampling) attempted were effective in assessing the vertical distribution of the seed bank and estimated the size of the seed bank to be within the same order of magnitude. However, random sampling will be more effective in assessing the seed bank size as it was found that the seeds have a clumped horizontal distribution. The vertical distribution of seeds in the seed bank was found to be influenced by soil properties. The largest portion of the seed bank is situated in the upper 0-10 cm of the soil and declines in size with depth. Impacts of ploughing and introduction of commercial fynbos species on the diversity of

sandstone fynbos on the Agulhas Plain, South Africa

M. Treurnichta; K.J. Eslera, M. Gaertnerb a Department of Conservation Ecology & Entomology, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa b Centre for Invasion Biology, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa

The Agulhas Plain is an area of exceptional biodiversity and is currently threatened by a number of (mostly) anthropogenic activities. Consequently it has been the focus of many research initiatives and conservation planning activities in recent decades. Amongst other agricultural activities, commercial fynbos farming is widely practised in the Agulhas Plain. The flower industry uses both cultivated and wild (‘natural veld’) harvested flowers. Recently there has been a growing trend away from ‘natural veld’ harvesting towards the intensive cultivation of certain fynbos species. Cultivation from ‘natural veld’ to produce economically desirable fynbos species includes the implementation of certain farming practices/techniques. Commercial fynbos farming has become a popular and lucrative industry which can potentially (according to our understanding) be detrimental to fynbos diversity. Our aim is to investigate impacts of commercial fynbos farming (focusing on harvesting from ‘natural veld’) on fynbos diversity in the Agulhas Plain. A vegetation survey will be performed to elucidate information about the impacts certain farming activities have on the structural and floristic composition of fynbos. We present preliminary results from our vegetation survey on the impacts such practices have on diversity. The insights gained from this study will aim to facilitate sustainable fynbos farming activities for the Agulhas area. SAAB bursar

The effect of water stress on the concentration of artemisinin and other metabolites in

Artemisia annua L.

J.M. van der Hout, J.J.M. Meyer Department of Plant Science, University of Pretoria, Pretoria, 0002, South Africa

Malaria is one of the deadliest diseases worldwide. An increasing problem is the malaria parasite`s resistance to the existing anti-malarial drugs. The discovery of artemisinin from Artemisia annua L. have provided a new class of effective antimalarials. The extraction of artemisinin from A. annua plants remains the only source of the drug. Due to the low artemisinin content in A. annua, strategies to increase the artemisinin content must be evaluated. By applying water stress to A. annua plants we evaluated the effect on the concentration of artemisinin as well as other

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metabolites. Progeny of the A. annua plants was cultivated to determine if water stress can epigenetically be transferred. We have used a NMR targeted metabolomic approach to identify the difference in the metabolites in A. annua plants cultivated under water stress and those not. NMR and a mathematical formula were used to determine the artemisinin concentrations. The results indicated that water stress will increase the artemisinin concentration and there is also a difference in the metabolite content. Artemisinin could not yet be detected in the progeny due to its early growth stage, which is associated with very low levels of artemisinin. Algal diversity on the rock-faces of the Golden Gate National Park

A. Venter, A.A. Levanets, J.C. Taylor School of Environmental Sciences and Development, North-West University, Potchefstroom, South Africa

The Golden Gate National Park (28 °31'S; 28 °37'E) covers about 12 000 hectares in the rugged Maluti Mountains. The geological formations within the park are of the Karoo Supergroup and consist mainly of flat lying sandstones and subsidiary stilstones and mudstones. The Clarens sandstone with its characteristic yellow and red weathering can be seen on almost all of the overhangs and is an important sponge area that absorbs and retains water for periods between rainfall incidents. These outcrops produce seepage water that creates suitable microenvironments for a diverse array of epilithic algal growth, especially on the western rock-faces. The seepage water is usually alkaline with a pH of about 9. The investigated diatom flora of the sandstone formations contained several species from the genera Amphora and Navicula. In addition, a naviculoid species with a cruciform, often asymmetrical, valve shape was also discovered. A species possibly from the genus Epithemia was also present but its identity is uncertain as it is linear in shape that is atypical for this genus. Cyanoprokaryotes include several species of Nostoc such as Nostoc microscopicum. Other cyanoprokaryotes include Pseudanabaena, Tolypothrix and Choococcus spp. A green algal genus, Chlorococcum as well as several desmid species were also found in these microenvironments. These studies as yet have only revealed a small part of the diversity of the aerophilic algal species of South Africa.

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INDEX OF AUTHORS A

Abdillahi H.S., 14, 23 Adebola P.O., 16, 53 Afolayan A.J., 12, 13, 14, 16, 24, 25, 51, 53 Ahmed S., 16, 61 Alberts W.G., 15, 46 Annegarn H.J., 14, 42 Aremu A.O., 13, 23 Arnolds J.L., 17, 53 Ascough G.D., 12, 42 B

Badmus A.A., 14, 24 Bairu M.W., 13, 24 Balkwill K., 12, 19 Begoude D., 16, 68 Begwa F.P., 16, 54 Berner J.M., 12, 13, 14, 34, 36, 45, 50 Blignaut J., 16, 68 Boatwright J.S., 12, 33 Botha F., 14, 29 Bredenkamp C.L., 16, 54 Bredenkamp G.J., 13, 33 Burgoyne P.M., 17, 69 Bvenura C., 13, 25 C

Cheesman L., 13, 25 Chinsamy M., 14, 26 Chukwujekwu J.C., 13, 23 Cilliers S.S., 12, 13, 14, 16, 17, 19, 26, 32, 56, 61, 62, 63, 65 Clarkson B., 14, 16, 30, 59 Coutinho T.A., 17, 58 Crampton B.G., 16, 17, 66 D

Davoren E., 14, 26 De Beer M., 12, 27 De Klerk T.C., 16, 56 De Wet L.-D., 17, 55 Deutschländer M.S., 14, 28 Devnarain N., 17, 55 Doležal K., 13, 24 Driver A., 12, 43 Du Plooy C.P., 14, 41 Du Toit M.J., 16, 56 E

Egoh B., 16, 68 Esler K.J., 13, 14, 17, 20, 37, 69, 70

F

Farrant J.M., 11, 20 Farrow B.J., 17, 57 Finnie J.F., 12, 13, 14, 23, 25, 26, 38, 39, 42 Fourie G., 17, 57 Furniss D.G., 14, 42 G

Gaertner M., 17, 70 Gilani S.A., 17, 57 Götze A.R., 16, 62 Gozo P., 16, 54 Gryzenhout M., 17, 58 H

Hakizimana J.D., 17, 58 Helm C.V., 14, 28 Hendriks C.B.S., 14, 29 Henley-Smith C.J., 14, 29 Hinze B., 16, 68 Hodges T., 14, 16, 30, 59 Hulley I.M., 13, 31 Hunter C., 17, 55 Hussein A.A., 14, 16, 31, 35, 60 I

Ibhanesebhor G.A.O., 14, 40 Iputo J.E., 16, 67 J

Jaca T.P., 16, 59, 60 Janse van Vuuren S., 12, 34, 48 Jordaan A., 11, 12, 17, 27, 45, 69 K

Kafua L., 16, 60 Kamatou G.P., 13, 31 Kambizi L., 16, 67 Kellner K., 12, 14, 17, 32, 50, 61 Kganye M.A., 16, 59, 60 Khanum R., 16, 61 Koch A.C., 14, 32 Kritzinger Q., 14, 16, 44, 60, 67 Kruger A., 16, 65 Krüger G.H.J., 12, 13, 17, 34, 36, 45, 53 Kruger N.J., 11, 36 Kulkarni M.G., 14, 38 Kunert K.J., 12, 40, 49, 50 Kurzweg S., 12, 17, 32, 61 L

Lall N., 14, 28, 29, 31, 35 Lamprecht A.J.H., 16, 62 Le Grange L., 13, 33

73

Le Roux M.M., 12, 33 Levanets A.A., 12, 17, 34, 71 Ligavha-Mbelengwa M.H., 16, 54, 64 Light M.E., 13, 23, 25 Lindeque S., 13, 34 Long H.S., 14, 35 Lubbe C.S., 17, 62 M

Magodielo M.M., 16, 63 Mahomed W., 17, 64 Malan E., 14, 43 Maleme H., 16, 68 Mancama D., 17, 66 Marais G., 16, 68 Mashile S.P., 16, 64 Masupa T.T., 12, 41 Mavundza E.J., 14, 35 McCarthy M.A., 11, 21 McCormick A.J., 11, 36 McFarlane S.A., 17, 55 Mehl J., 16, 68 Meyer J.M.M., 14, 29 Meyer M., 14, 16, 31, 70 Michaud D., 12, 50 Minnaar M.M., 12, 36 Mohase L., 17, 65 Mokotjomela T.M., 14, 37 Molebatsi L.Y., 16, 65 Moodley N., 16, 66 Moteetee A.N., 11, 12, 33, 38 Mudau F.N., 14, 35 Mulaudzi R.B., 14, 38 Mumtaz A.S., 16, 61 Musil C.F., 14, 17, 37, 53 Myburg A.A., 17, 64 N

Ndebia E.J., 16, 67 Nemutanzhela M.E., 16, 17, 66 Ngunge V.N.P., 12, 39 Ngwenya G.L., 16, 66 Nkeh-Chungag B.N., 16, 67 Nkomo M., 16, 67 Nkwanyana P.D., 12, 39 Novák O., 12, 13, 24, 47 O

Oke S.O., 14, 40 P

Papenfus H.B., 16, 67 Pavlic D., 16, 68 Pillay P., 12, 40

Potter D., 17, 57 Prinsloo G., 14, 41, 44 Q

Qureshi R.A., 17, 57 R

Ramgareeb S., 14, 32 Rampho E.T., 16, 54 Rapson J., 14, 16, 30, 59 Retief E., 12, 41 Retief F.P., 16, 63 Rice L.J., 12, 42 Robertson A., 14, 16, 30, 59 Rossouw A.S., 14, 42 Rouget M., 12, 16, 43, 68 Roux J., 14, 16, 43, 47, 68 Rutherford R.S., 14, 17, 32, 55 S

Sathekge N.R., 14, 44 Schaminée J.H.J., 13, 33 Scheepers C.C.W., 13, 45 Schipper L., 14, 16, 30, 59 Schluter U., 12, 40, 49 Siebert S.J., 11, 12, 14, 16, 17, 26, 32, 45, 61, 62, 63, 65, 69 Six D., 14, 47 Slippers B., 16, 68 Smith T., 12, 43 Smith V., 12, 48 Snyman S.J., 12, 14, 17, 32, 39, 55 Steenkamp E.T., 17, 55 Stirk W.A., 12, 47 Strnad M., 12, 47 Struwig M., 11, 16, 17, 45, 65, 69 Strydom M., 17, 69 Swanepoel K.M., 15, 46 T

Taiwe B.M., 17, 65 Tastan Bishop Ö., 12, 50 Taylor J.C., 12, 17, 34, 71 Tiedt L.R., 11, 45 Tilney P.M., 12, 13, 14, 31, 33, 35, 46 Treurnicht M., 17, 70 Tshikalange T.E., 14, 35 Tshisikhawe M.P., 16, 54, 64 V

Van de Venter M., 14, 28 Van den Berg N., 17, 57, 58, 64 Van der Hout J.M., 16, 70 Van der Linde J.A., 14, 16, 47, 68 Van der Merwe C.F., 14, 29

74

Van der Merwe S., 14, 43 Van der Walt F., 16, 68 Van Heerden P.D.R., 12, 27 Van Rensburg L., 12, 34, 48 Van Rooyen M.W., 14, 43 Van Staden J., 12, 13, 14, 23, 24, 25, 26, 38, 39, 42, 47 Van Staden W., 12, 48 Van Vuuren S.F., 13, 31 Van Wyk B.-E., 11, 12, 13, 14, 31, 33, 35, 38, 46, 49 Van Wyk S.G., 12, 49 Venter A., 12, 17, 34, 71 Venter L., 16, 59, 60

Viljoen A.M., 13, 31 Viljoen J.C., 14, 41 Vorster B.J., 12, 49, 50 Vorster J., 12, 40 W

Watt M.P., 12, 14, 32, 39 Weiersbye I.M., 14, 42 Westcott M., 14, 50 Wingfield B.D., 16, 17, 55, 68 Wingfield M.J., 14, 16, 17, 43, 47, 55, 68 Wintola O.A., 12, 51 Wood A.R., 17, 69 Z

Zobolo A.M., 11, 51

75

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36th Annual Conference of the South African Association of ......A new student council member for the 2010/2011 period will be elected ... Danie Huyser Sarel Cilliers Anine Jordaan