DNA polymorphism, allozyme diversity and biomass of Cyperus papyrus L. in Kenya’s wetlands

DNA polymorphism, allozyme diversity and biomass of Cyperus papyrus L. in Kenya’s

wetlands

By

Taita Terer

Promoter: Prof. Dr. Ludwig Triest

Laboratory of General Botany & Management

INTRODUCTION Wetland definition

The 1971 Ramsar convention defined wetlands as areas of marsh, fen, peat land or water, whether natural or artificial, permanent or temporary with water that is static or flowing, fresh, brackish or salty including areas of marine water the depth of which at low tides does not exceed six meters.

Papyrus swamps are important tropical wetlands.

Cont… Papyrus plant description

Morphologically it is plant with bluntly triangular stem, long sharp-keeled leaves and grows up to an average height of 4-5 m.

Taxonomically it is a monocot (Cyperaceae) It is one of the highly productive plants with

biomass in excess of 6000g/m2/year. It reproduce both vegetatively (rhizomes) and

sexually (seeds).

Papyrus plants

Cont… Distribution

It is the largest sedge in the world and an indigenous aquatic macrophyte to African continent and Israel.

In Kenya it is a dominant feature of Lake Victoria, Rift Valley region and streams draining into Tana River in Central Kenya.

Generally it grows along the river banks (e.g. in Ruiru), shores of the lake (e.g. Naivasha), at the mouth of rivers (e.g. Nyando) and groundwater fed (e.g. Amboseli).

Cont… Importance and uses

Ecological fucntions Important support for biodiversity (water plants,

waterfowls, breeding ground for native fish). Controls soil erosion and trap sediments. Reduces pollution (nutrient sink).

Socio-economic uses Use for roofing houses Source of energy Household furniture

Sofa set

Cont… Sources of disturbance

Trampling. Cattle grazing. Harvesting. Cultivation. Direct impact on wetland vegetation

Resilience (biomass regrowth. Reproduction (clonal versus sexual).

Burning ( see photo below).

Cutting and burning

OBJECTIVES The objectives of this study were:

To document from the existing data and primary information the biogeographical distribution of papyrus plants in Kenya.

To estimate the standing above-ground biomass in different wetland types.

To assess the genetic diversity and structure of papyrus under different geographical locations, wetland sizes and disturbances.

• 1. R. Kibos

• 2. R. Nyando

• 3. R. Sondu

• 4. Loboi swamp

• 5. Ruiru River banks

• 6. L. Naivasha

• 7. Amboseli swamp

Mombasa

Nairobi

L. VictoriaKENYA

0°

L. Turkana

1

32

45

6

7

MATERIALS AND METHODS Biomass measurement design

Height

Culm circumference

40X 40X 40X

Old Mature Young

6 Wetlands

3 QuadrantsFresh & Dry weight

Random

Cont… Genetic diversity sampling design

7 Wetlands

(ca. 350 clones)40 – 60 clones (GPS)

Disturbed areasUndisturbed areas

2 cm stems Fresh transport to VUB - 80°C Extraction

Cont… Laboratory analysis

Biomass Samples were dried first in the sun for 2-3 days

and oven-dried to constant weight at 60-85 °C.

Dry weight measurements were carried out for >720 individual plants taken from all the sites.

Genetic diversity Electrophoresis was run for allozyme and PCR

for DNA polymorphism.

PRELIMINARY RESULTS Laboratory analysis (still

in progress) Selection of Isonzymes

A total of 17 isonzymes were screened.

Polymorphic isonzymes are:GOT-AAT ADH,GDH, EST & SDH.

SDH reveals clonal diversity 10 samples from

River Sondu.

10 samples from River Kibos.

WAY FORWARD Further analysis

Enzyme polymorphism (02.2004). Of 360 samples collected for genetic diversity analysis, only 250 have been analysed. The results obtained will be used to determine: Heterozygosity (genetic diversity). Hierarchical F-statistics. Genetic distance among the 7 populations. Clonality using multilocus genotypes. Spatial autocorrelation in each population.

WAY FORWARD DNA fragment analysis (02-07.2004).

Regional diversity Local clonality

Biomass (02-05.2004). Relationship between culms girth circumference

and biomass will be determined and regression graphs drawn for each study site.

THANK YOU FOR YOUR ATTENTION