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Dr. S.K. Jogdand
P.G. Dept. of Botany
Mrs. K.S.K. College Beed
Orchids of Western Ghats
Orchids, one of the beautiful creations of the
nature, comprise an unique group of plants. Being one of the
largest families of the flowering plants, Orchidaceae constitutes
about 7% species of all Angiosperms and nearly 40% of
monocotyledons. It is one of the largest and most diversified
families of Angiosperms represented by 25,000 to 35,000
species belonging to 600 – 800 genera (Arditti, 1979)
distributed in all parts of the world except, perhaps, in the
Antarctica (Abraham and Vatsala, 1981). India represents about
1,141 species belonging to 140 genera of orchids with
Himalayas as their main home (Kumar and Manilal, 1994).
Orchids are perennial herbs and exhibit incredible range of
diversity in habit; shape, size, colour and fragrance of flower
and its fascination. Orchids are highly evolved among the
monocotyledons and also possess evolved flower and seed.
The Western Ghats of India, one of the salubrious spots providing
vast range of habitats for a good number of orchid species is one of
the Hot- Spots of endemic plants of India. It is the second richest and
diverse spot as far as orchids are concerned. It harbors 267 species, 3
subspecies, and 2 varieties of orchids belonging to 72 genera of
which more than 46% are endemic. Orchidaceae are one of the
dominant families in the Western Ghats only next to the Poaceae and
Leguminoceae.
Among the Monocotyledons, family Orchidaceae is found to be
interesting for its Taxonomy, Cytogenetics, Adaptations, and
Propagation.
During speciation orchids have adapted themselves to various
habitats ranging from open grassland to high mountains.
To conserve the endemic species a multifaceted approach of study
is necessary.
A large number of indigenous wild orchids are highly ornamental
and are in great demand.
No proper steps have been taken to study these orchids for their
mass propagation using conventional as well as non-conventional
techniques.
No studies are performed for their improvement and utilization as
ornamental species.
Orchids attracted man from its civilization because of exquisite
beauty along with so many unique characters of the flower. It has
always remained attraction of botanists.
THE WESTERN GHATS
Conspicuous geographical
feature of the peninsula.
One of the eight hottest hot
spots of world.
Salubrious spot providing
vast range of habitats.
It runs about 1600 km.
Straddle the states of Gujarat,
Maharashtra, Karnataka,
Goa, Tamil Nadu and Kerala.
Harbors 4000 species of
flowering plants with 50%
endemic elements.
Second richest and diverse
geographic zone of India.
Palghat
gap
Cronquist (1981)
Class- Liliopsida
Sub class- Lillidae
Order- Orchidales
Family- Orchidaceae
Taxonomy of orchids
Growth habits of orchids
1. Terrestrial Orchids: Habenaria, Peristylus, Eulophia, Malaxis
2. Saprophytic Orchids: Epipogium, Choralorhiza
3. Aquatic Orchids: Eulophia ramentacea, Zeuxine strateumatica
4. Epiphytic Orchids: Aerides, Vanda, Rhynchostylis, Dendrobium,
Thunia
Organs of the orchid plant
1. Root
2. Rhizome
3. Pseudobulb
4. Leaf
5. Inflorescence
6. Flower
7. Fruit
8. Seed
Growth patterns of orchids
1. Sympodial type: All terrestrial orchids,
Cymbidium, Thunia,
Dendrobium, Bulbophyllum, etc.
2. Monopodial Type: Aerides, Vanda, Rhynchostylis,
Cottonia
3. Pseudomonopodial (Diapodial) type:
Cleisostoma
Vegetative propagation
1. Division
2. Back bulbs
4. Offsets/ Keikis5. Air layering
3. Cuttings
Distribution of orchids
(Orchid zones of India: Bose et al., 1999)
1. Plains (Sea level to 300m): Acampe praemorsa, Pholidota pallida
2. Tropical zone (300-900m): Rhynchostylis retusa, Nervilia aragoana
3. Sub tropical zone (900-1800m): Dendrobium, Habenaria, Thunia
4. Temperate zone (1800-3500m): Aerides, Arachnis, Cymbidium
5. Alpine zone (3500-5000m): Bulbophyllum rretusisculum,
Habenaria cumminsiana,
Nervilia macroglossa,
Bentham and Hooker (1883)
Tribe 1. Epidendreae: Anther one, terminal, deciduous; Pollinia waxy,
1 - 4, held together by a viscid appendage (Nine subtribes).
Tribe 2. Vandeae: Anther one; Pollinia Waxy, 2 or 4 in superimposed
pairs, attached to a gland or part of the rostellum which is
carried away when pollinia is removed (Eight subtribes).
Tribe 3. Neottieae: Anther one, terminal, with 2 distinct parallel cells;
Pollinia granular, powdery or sectile (Six subtribes).
Tribe 4. Ophrydeae: Anther one, posterior; Pollinia solitary, granular,
produced into caudicles attached to a gland or to the rostellum.
Terrestrial (Six Sub tribes).
Tribe 5. Cypripedieae: Anthers 2, at the sides of the rostellum, with
parallel contiguous cells; Pollen granulose; Lip inflated, shoe shaped.
Classification of orchids
1. Orchids as botanicals
2. Orchid as spice
3. Orchids as medicine
4. Orchids as food
5. Orchids as cultural activities
6. Orchids as ornamentals
Economic Importance of orchids
A. COLLECTION, IDENTIFICATION,
DISTRIBUTION AND PRESENT
STATUS OF ORCHID SPECIES
FROM STUDY AREA
Sr.
No.
Orchid species reported in Total No. of
orchid
species
Endemic
orchid
species
1 India 1141 344
2 Peninsular India 322 136
3 Western Ghats 267 84
4 Study area of present work 109 41
5 Cultivated in Botanic Garden 74 32
The floristic account of Orchidaceae
Established an Orchidarium
44 Tahsils, 41 genera and 109 species
52 epiphytic and 57 terrestrial species
Comparative account of endemic species of orchidsN
o. o
f sp
ecie
s
1141
344 322267
13684
109
4174
32
Species distribution in various orchid genera
ADAPTATIONS IN ORCHIDS
0
5
10
15
20
25
30
35
Janu
ary
Febru
ary
Mar
chApr
ilM
ayJu
neJu
ly
Augus
t
Septe
mbe
r
Oct
ober
Novem
ber
Decem
ber
Throu
gh o
ut year
Month
No
. of
spec
ies
in f
low
erEpiphytic species
Terrestrial species
Flowering calendar of orchids
S = Sympodial (79 species) M = Monopodial (18 species)
P = Pseudomonopodial/ Diapodial (12 species)
Total = 109 species.
Adaptations in Flowers:
i) Epiphytic orchids produce colourful and fragrant flowers as
compared to terrestrial ones.
ii) Orchids like Habenaria grandifloriformis, H. crinifera, H.
longicorniculata and Pecteilis gigantea glitter during night and
attract nocturnal insects like Hock moths.
iii) White flowered terrestrial orchids are always sweet scented and night
blooming and dull coloured flowers of terrestrial orchids are foul
scented. In Habenaria gibsoni, H. foetida and H. foliosa stratification
of insects is based on odour of flowers.
iv) The labellum shows great diversity in size, shape, colour and form.
The labellum might play important role in the stratification of insect
pollinators e.g. pollination biology of Cottonia peduncularis (Yadav,
1995).
v) To avoid the self pollination in orchids the third stigma is modified in
to the partition wall called rostellum.
Aerides dalzelliana Aerides ringens
Dendrobium crepidatum
Habenaria grandifloriformis
Diversity in Labellum
Adaptations in Seeds:
i) All orchids produce millions of minute seeds in the capsules. Production
of minute but numerous and very buoyant seeds seems to be an
adaptation against the selection by chance in nature. (Wright, 1931).
ii) There are equal chances of survival or death of fungus and seed as well
as symbiotic equilibrium Bernard (1904).
iii) Orchid seeds being small in size and light in weight are adapted for
wind and water dispersal.
a) Buoyancy of orchid seeds - seed/embryo volume ratio-seed
dispersal- distribution of the species.
b) Species with highly buoyant seeds are widely distributed.
c) Species with less buoyant seeds but widely distributed: they might
have great adaptive amplitude to diverse habitats.
d) Orchids with highly buoyant seeds but having narrow range
of distribution because of their habitat specificity.
Sr.
No.Orchid species
Seed/
embryo
volume ratio
Range of
Distribution*
1 Acampe praemorsa Blatt. & McC 1.304 Narrow
2 Aerides crispum Lindl. 1.153 Narrow
3 Aerides maculosum Lindl. 1.196 Narrow
4 Bulbophylum fimbriatum Rich 1.809 Narrow
5 Cottonia penducularis Reich. 1.342 Narrow
6 Cymbidium aloifolium Bl. 4.511 Wide
7 Dendrobium aqueum Lindl. 1.397 Narrow
8 Dendrobium barbatulum Wt. 3.022 Narrow
9 Dendrobium crepidatum Lindl. 2.210 Wide
10 Dendrobium lawianum. 1.943 Wide
11 Dendrobium macrostachyum 1.345 Narrow
12 Dendrobium microbulbus
Blatt. & McC.
1.345 Narrow
13 Dendrobium nanum J.D.Hook 3.208 Narrow
14 Dendrobium ovatum Kranz. 2.645 Narrow
15 Eria reticosa Wt. 1.982 Wide
16 Eulophia nuda Hook. f. 8.221 Wide
Sr.
No.Orchid species
Seed/
embryo
volume ratio
Range of
Distribution*
17 Geodorum densiflorum Schltr. 10.396 Wide
18 Lusia zeylanica Lind. 1.365 Wide
19 Malaxis rheedei Sant. & Kap. 2.980 Wide
20 Oberonia brachyphylla Blatt. & McC. 1.421 Narrow
21 Oberonia falconeri Hook. F. 1.331 Wide
22 Oberonia recurva Lindl. 4.057 Wide
23 Oberonia wightiana Lindl. 3.076 Wide
24 Peristylus goodyeroides Lidl. 4.053 Wide
25 Pholidota pallida Lind. 3.215 Wide
26 Polystachya concreta Hook. f. 1.387 Wide
27 Rhynchostylis retusa Bl. 1.041 Wide
28 Thunia venosa Rolfe. 2.264 Narrow
29 Vanda testacea Lind. 1.139 Wide
30 Zeuxine gracilis Bl. 3.989 Wide
31 Zeuxine longilabris Bth. 4.097 Wide
32 Zeuxine strateumatica Schltr. 2.598 Wide
Seed/ Embryo volume ratio
* Kumar and Manilal (1994)
Sr. Orchid species Viability (%)
1 Acampe praemorsa Blatt. & McC 99.37
2 Aerides crispum Lindl. 94.50
3 Aerides maculosum Lindl. 80.48
4 Bulbophylum fimbriatum Rich 77.27
5 Cottonia penducularis Reich. 99.09
6 Cymbidium aloifolium Bl. 100
7 Dendrobium aqueum Lindl. 68.25
8 Dendrobium barbatulum Wt. 100
9 Dendrobium crepidatum Lindl. 92.85
10 Dendrobium lawianum. 90.69
11 Dendrobium macrostachyum 94.73
12 Dendrobium microbulbon
Blatt. & McC.
83.87
13 Dendrobium nanum J.D.Hook 96.59
14 Dendrobium ovatum Kranz. 98.96
15 Eria reticosa Wt. 93.87
16 Eulophia nuda Hook. f. 100
17 Geodorum densiflorum Schltr. 100
18 Lusia zeylanica Lindl. 78.46
19 Malaxis rheedei Sant. & Kap. 100
20 Oberonia brachyphylla Blatt. & McC. 79.77
21 Oberonia falconeri Hook. F. 100
22 Oberonia recurva Lindl. 84.26
23 Oberonia wightiana Lindl. 67.61
24 Peristylus goodyeroides Lidl. 75.60
25 Pholidota pallida Lind. 78.94
26 Polystachya concreta Hook. f. 94.33
27 Rhynchostylis retusa Bl. 88.70
28 Thunia venosa Rolfe. 82.60
29 Vanda testacea Lind. 100
30 Zeuxine gracilis Bl. 91.30
31 Zeuxine longilabris Bth. 92.50
32 Zeuxine strateumatica Schltr. 51.72
Sr. Orchid species Viability (%)
Viability of orchid seeds in mature fruit
Seed diversity in orchids
The energy budget of every
species is limited. Orchids produce
numerous seeds and enjoy benefit
of effective seed dispersal.
However, on the other hand the
seeds are not equipped with
reserved food material and most of
them fail to germinate or wasted
which is disadvantage to the
orchids.
6. Stomatal behaviour:
Sixteen orchid species suspecting
CAM were investigated for their
stomatal behaviour and it was found
that the stomata remains tightly closed
during day time and opens during
night in most of them.
The nocturnal opening of stomata
in thick leaved orchids such as
Arachnis, Aranda and Cattleya was
observed by Arditti (1979).
In the present investigation similar
results are noticed.
This stomatal rhythm is an
adaptation of some of the orchid
species to semiarid conditions and
seasonal variation in water
availability.
7. Crassulacean acid metabolism:CAM provides a dramatic
example of ‘strategies’ that
enable plants to consolidate
their water and carbon
balance in arid environments;
allowing the plant to conquer
ecological niches where
water is deficient (Kluge,
1972).
In the present
investigation, the CAM
pathway of carbon
assimilation has been
detected in all orchid species
suspecting CAM except only
Flickingeria macraei Lind.
Sr.
No.
Orchid species TAN Value*
6 am 12 noon 6 pm 12 night Δ acidity
1 Bulbophyllum
neilgherrense
270.27 202.69 131.07 175.66 139.20
2 Dendrobium crepidatum 225.66 81.07 58.10 98.64 167.56
3 Flickingeria macraei 94.59 17.56 98.64 12.16 - 4.05
4 Luisia evangelinae 108.10 40.53 13.51 27.02 94.59
5 Luisia macrantha. 185.12 131.07 44.59 67.56 140.53
6 Luisia zeylanica 212.15 49.99 27.02 54.05 185.13
7 Oberonia brunoniana. 94.59 40.53 27.02 49.99 67.57
8 Oberonia ensiformis . 202.69 94.59 67.56 85.13 135.13
9 Oberonia falconeri 198.64 90.53 49.99 77.02 148.65
10 Oberonia iridifolia. 152.69 54.05 40.53 63.51 112.16
11 Oberonia platycaulon 125.67 49.99 44.59 54.05 81.08
12 Oberonia recurva 162.15 49.99 44.59 54.05 117.56
13 Oberonia verticillata 135.13 58.10 54.05 71.61 81.08
14 Oberonia wightiana . 104.05 54.05 36.48 44.59 67.57
15 Trias stocksii 239.18 121.61 54.05 104.05 185.13
16 Vanilla walkeriae 239.18 104.05 71.61 112.15 167.57
Similar results on thick-leaved orchids were reported earlier by various workers
(Neurenbergk, 1963; Borris, 1967 and McWilliams, 1970). However, in Flickingeria
macraei Lind. the fibrous nature of pseudobulbs and leaves and less amount of mucilage
probably makes it incapable of storing the water for long period during drought. Thus, to
know the alternative mechanism in this orchid for its survival under drought requires
further investigation.
8. Total polyphenols in orchids:
Sr.
No.Orchid species
Total Polyphenols (g/100 g of dry
wt.)
DifferenceMonsoon
(August)
Summer
(March)
1 Acampe praemorsa Blatt. & McC. 0.172 1.249 1.077
2 Aerides crispum Lindl. 2.072 1.238 - 0.834
3 Aerides maculosum Lindl. 0.705 1.438 0.733
4 Bulbophylum neilgherrense Wt. 1.473 1.351 - 0.122
5 Cottonia peduncularis Reich. 0.795 0.870 0.075
6 Cymbidium aloifolium Bl. 0.352 1.019 0.667
7 Dendrobium aqueum Lindl. 0.442 1.730 1.289
8 Dendrobium barbatulum Wt. 0.729 0.859 0.130
9 Dendrobium crepidatum Lindl. 1.769 1.359 - 0.410
10 Dendrobium lawianum Lindl. 0.367 2.599 2.232
11 Dendrobium macrostachyum Lindl. 1.573 0.764 - 0.809
12 Flickingeria macraei Lind. 1.093 1.954 0.861
13 Oberonia brachyphylla Blatt. & McC. 0.329 2.728 2.399
14 Oberonia wightiana Lindl. 1.882 2.536 0.654
15 Rhynchostylis retusa Bl. 0.227 0.558 0.331
16 Vanda tessellata Hook.f. 0.651 2.002 1.351
17 Vanda testacea Lindl. 1.916 1.654 - 0.262
18 Vanilla walkeriae Wight 0.960 1.095 0.135
1 Dendrobium herbaceum Lindl. ---- 0.733
2 Dendrobium microbulbon Blatt. & McC. ---- 0.979
3 Dendrobium nanum J.D.Hook ---- 5.988
4 Dendrobium peguanum Lind. ---- 2.548
5 Luisia evangelinae Blatt. & McC. ---- 2.967
6 Luisia zeylanica Lindl. ---- 2.362
7 Trias stocksii Bth. ---- 1.724
The presence of phenolic
compounds in orchids was noticed
earlier by Sanford et al. (1965) and
Withner and Stevenson (1968).
According to Sanford (1974)
secondary substances such as
phenolics may vary from plant to
plant and from time to time and
hence the orchid species may have
physiological plasticity.
In many other plants the
polyphenols are found to synthesize
in response to water stress (Todd et
al., 1974; Talha et al., 1975 and
Nalawade, 1983), but its role in
orchids is still unknown.
The increase in amount of
polyphenols during summer may be
due to adaptive response of these
orchids to secondary metabolism.
Wild orchids of ornamental potential
Orchids as ornamentals
E. MULTIPLICATION OF SOME HORTICULTURALLY
VALUABLE ORCHIDS THROUGH TISSUE CULTURE
No. Name of species Period required for
protocorm development
(Days)
Seed germination % /Medium
KC MS M
1 Acampe praemorsa 40 + + + + + +
2 Aerides maculosum 35 + + + + + + + + +
3 Dendrobium macrostachyum 45 + + + + + + + +
4 Eulophia nuda 30 + + + + + + + + + +
5 Geodorum densiflorum 21 + + + + + + +
6 Pecteilis gigantea 30 + + + + + + +
7 Pholidota pallida 28 + + + + + + + +
8 Rhynchostylis retusa 35 + + + + + + + + + + +
9 Thunia venosa 28 + + + + + + + + +
1. In vitro seed germination study
+ + + + - More than 90 % KC = Knudson C (1946)
+ + + - 60 – 90 % MS = Murashige and Skoog (1962)
+ + - 25 – 60 % M = Mitra et al. (1976)
+ - up to 25 %
*The difference in response to media may be attributed to the species used (Arditti and Ernst, 1984).
Thunia venosa
Thunia venosaThunia venosa
4. Protocol of seed germination, seedling growth and hardening of
seedlings in Thunia venosa: (KC medium)
Sr. No. Parameter Liquid medium Semisolid medium
1 Seedling development Within 3 months More than 3 months
2 Nature of seedling Fragile, bulbous, free floating Normal
3 Growth rate + + + + +
4 Response to hardening + + + + +
In vitro multiplication of
T. venosa on KC medium