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