Micropropagation in orchid

1. Submitted by
Aswin M B
Biochemistry & molecular biology
BBM052007

2. “If nature ever showed her playfulness in the formation of flowers, this is visible in the most
striking way among the orchid.”
Orchids are grown primarily as ornamentals & are valued as cut flowers not only because of
their exotic beauty but also for their long shelf life. Orchids are grown primarily as ornamentals,
some are employed as herbal medicines & food by many different cultures and tribes.
Several species belonging to
the genera Anoectochilus,
Goodyera, Ludisia &
Macodes termed as Jewel
orchids are grown especially
for their beautiful foliage.
Vanilla is one of the
rare examples of
orchids being used as
spices.
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3. Problems phased by Orchid plants
Many orchid species such as Rhynchostylis & Paphiopedium delanti are threatened with danger
of extermination through deforestation & indiscriminate collection. At present the orchids also
figure prominently in the Red Data Book prepared by International Union of Conservation of
Nature and Natural Resources(IUCN).
The seeds of the orchids, produced in large number in each capsule, are highly fragile &
possess virtually no stored food material or endosperm (Mitra,1971).
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4. • The Indian government has established Biosphere reserves, National parks & Sanctuaries in the
orchid rich regions of the country besides banning the export of orchids collected in wild.
Unfortunately, In situ conservation is not always a viable option because of reasons like
fragmented habitats, absence of pollinators due to indiscriminate use of pesticides or other
modifications of the biome.
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5. Introduction
Micropropagation is a method for obtaining large numbers of clonal explants in a short
duration.
This can be feasible in a short space of time.
Micropropagation methods were used in 1960 by George Morel for the production of orchid
plants at a commercial level.
Micropropagation was first proposed in 1968 & defined as an aseptic procedure for the
asexual production of plantlets from organs, tissues & cell bypassing the sexual process or
other means of asexual propagation.
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6. • Orchids are prized for their beautiful long lasting flowers exhibiting an incredible
range of diversity in size, shape, & colour.
• It is an international business covering around 8% of the world floriculture trade
and has the potential to alter the economic landscape of a country.
• Large-scale multiplication of exquisite and rare hybrids using tissue culture
techniques has helped orchids occupy a position as one of the top ten cut flowers.
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7. Micropropagation of orchid
 There are thousands of commercial orchids that are artificially grown for their beautiful flowers
& glycosidal importance.
 Orchid flowers with persistant perianths in which the segments do not drop as in many other
flowers are of high value as cut flowers. Flowers of Vanda, Cattleya & Phalaenopsis remain
fresh for 1-2 week, Cypripedium & paphiopedilum last for a month & Cymbidium spikes
remain fresh for 3-4 weeks.
 Roy Chowdhary & Mishra reported that some orchids have medicinal properties, such as blood
clotting in wound (Cymbidium giganteum), antidote for poisoning & abdominal complaints
(Vanda tessellate), healing of wounds (Cymbidium aloifolium), hysteria (Vanda spathulata) &
oral contraceptives (Cymbidium madidum).
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11. Shoot tip culture
Morel & Martin(1952) reported the production of free dahlias using apical meristem
culture & later applied technique to produce virus-free cymbidium.
Shoot tips from both in vitro and mature plants responded by formation of buds on
medium containing 8.8μM BAP & 4.4μM NAA.
Shoot tip culture can be used as a more reliable technique for tissue culture of sympodial
orchids like Dendrobium, Cymbidium, Arondina & Phaius.
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12. Leaf segment culture
• In the orchid Malaxis paludosa, buds naturally form on leaf tips. Therefore, the formation of
Calli & plants from leaf tips may merely reflect an inherent trait of the orchidaceous which is
‘brought out’ by the culture medium.
• Successful micropropagation using leaf explants depends on many factors:
o Medium nutrient composition
o Growth hormones
o Source of the leaf taken
o Explant orientation
o Most importantly the age of the leaf
• The embryo formation on leaf explants was retarded by auxins, IAA, IBA, 2,4-D but promoted
by cytokinin's like 2iP, zeatin, BAP & TDZ.
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14. Rhizome segment culture
• The multiplication rate of the oriental Cymbidiums under natural conditions is very low as
compared to the tropical or subtropical orchids.
• Shoot differentiation in rhizome cultures also occurred when the amounts of ammonium &
potassium nitrate were reduced to 412.5mg/l & 950mg/l respectively from 1650mg/l &
1900mg/l, respectively in hormone free MS medium.
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15. Root culture
• Possibility of using aerial roots for micro propagating orchids was earlier suggested by Beechey
(1970) even though the capacity of orchid roots to form shoots is low.
• Auxin, cytokinin & other substances like p-coumaric acid which interfere with endogenous IAA
oxidase activity influence the direct conversion of isolated root tip segments of catasetum into
PLBs.
• Presence of exogenous auxin in the media drastically reduced the number of PLBs formed, but
greatly increased callus formation. P- coumaric acid which has stimulatory effect on IAA
oxidase & causes eventual decrease in the endogenous levels of auxin increases.
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18. Micropropagation has become a suitable alternative to conventional methods of vegetative
propagation of plants. There are several advantages of micropropagation.
1. High rate of plant propagation
2. Production of disease – free plants
3. Production of seeds in some crops
4. Cost – effective process
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19. P roblems in o rc hid
micropropagation
1) Orchid cells in tissue culture exude a large quantity of phenolics that become toxic to the cells
when oxidized.
2) Transplantation stage
3) Soma clonal variation
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20. • Modern propagation and production technology has made orchids accessible to a
much broader section of the society. The fact that all major commercial tissue culture
laboratories in the world are involved in orchid micropropagation emphasizes how
popular these flowers have become.
• Development of new hybrids and their commercial cultivation have now become a
lucrative industry in many countries of the world.
• The rising popularity of orchids has created a demand for high quality plant
materials for the development of orchid industry.
• Training workshops in tissue culture techniques and hybridization to develop new
novel hybrids will also help to create job opportunities. It is felt that due to
tremendous uniformity in vegetatively propagated plants, the future mass-market
orchids will most likely be explant propagated and not seed propagated.
• Cost efficient protocols for mass propagation of rare, threatened and endangered
orchids, new hybrids, as well as transgenic orchids have to be developed further in
order to commercialize and conserve them.
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21. References
• Samira Chugh, Satyakam Guha, I. Usha Rao., 2009. Micropropagation of orchids: A review on the potential of
different explants. Scientia Horticulturae. 122, 507-520.
• Begum, A.A., Tamakli, M., Kako, S., 1994. Formation of protocorm-like bodies (PLB) and shoot development
through in vitro culture of outer tissue of Cymbidium PLB. J. Jpn. Soc. Hortic. Sci. 63, 663–673.
• Goh, C.J., Tan, H., 1979. Clonal propagation from leaf explants in an orchid hybrid Renanthera ammani. Plant
Physiol. 63, 161.
• Arditti, J., 1992. Fundamentals of Orchid Biology. John Wiley & Sons, New York.
• Arditti, J., 2008. Micropropagation of Orchids, 2nd ed. Blackwell, Cambridge.
• Arditti, J., Ernst, R., 1993. Micropropagation of Orchids. John Wiley & Sons, New York.
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