What
is Plant Tissue Culture??
Plant tissue
culture can be defined as culture of plant seeds, organs, explants, tissues, cells,
or protoplasts on nutrient media under sterile conditions. Broadly refers to
technique of growing plant cells, tissues, organs, seeds or other plant parts
in a sterile environment on a nutrient medium. The first commercial use of
plant propagation on artificial media was in the germination and growth of
orchid plants in the 1920’s. It was only after the development of a reliable artificial
medium by Murashige & Skoog in 1962 that plant tissue culture really took
off commercially.
In agriculture,
plant cell, tissue and organ culture is used for rapid and economic clonal multiplication
of fruit and forest trees, for production of virus free genetic stocks and planting
material as well as in the creation of novel genetic variations through
somaclonal variation. Genetic engineering techniques are utilized to produce
transgenic plants with desirable genes like disease resistance, herbicide
resistance, increased shelf life of fruits etc.
History
of Plant Tissue Culture
1902: First
attempted by Haberlandt. They grew palisade cells from leaves of various plants
but they did not divide.
1934: White
generated continuously growing culture of meristematic cells of tomato on
medium containing salts, yeast extract and sucrose and 3 vitamin B (pyridoxine,
thiamine, nicotinic acid) – established the importance of additives.
1953: Miller
and Skoog, University of Wisconsin – Madison discovered kinetin, a cytokine
that plays an active role in organogenesis.
1958 – 1960: Morel
cultured orchids and dahlias freed them from a viral disease.
1962: Murashige
and Skoog published recipe for M&S medium.
60’s and 70’s: Murashige
cloned plants in vitro. They raised haploid plants from pollen grains and used
protoplast fusion to hybridize 2 species of tobacco into one plant contained 4N.
70’s and 80’s:
Beginning of genetic engineering.
Why do plant tissue culture?
• Fast commercial
propagation of new cultivars
• Agriculture
– Fast selection for crop improvement – nutritional value, pest
control, hardiness
– Cultivation virus free plants
• Pharmaceuticals – ginseng and taxol
• Cloning of rare and endangered plants
•
Plant cultures in approved media are easier and safer to export.
