Plant Tissue Culture Techniques
Plant tissue culture is a technique with which plant cells, tissues or organs are grown on artificial nutrient medium, either static or liquid, under aseptic and controlled conditions. The key word behind the success of tissue culture is the totipotency.
The cultivation of cells in quantity, clones of single cell, a whole plant from single cell, tissue or organ — in vitro is possible with the use of various tissue culture techniques. These plant tissue culture techniques are as listed below:
- Callus culture
- Meristem culture
- Organ culture
- Protoplast culture
In the first one callus culture, the callus is a mass of highly vacuolated, unorganized cells resulting as a consequence of wounding in plants, and in tissue culture with the use of sophisticated techniques. A cell, may be from pollen, anther, bud, fruit, leaf or shoot apex etc. when cultured on a suitable growth medium under aseptic, controlled conditions, differentiate and multiply to form callus. This callus by induced re-differentiation can give rise to embryoids. Embryoids develop into plantlets and later on into a whole viable plant.
Callus culture works on some basic principles. These are aseptic preparation of plant material, selection of suitable growth medium (auxin : cytokinin ratio is important to consider), selection of suitable controlled physical growth conditions for incubation.
In the second meristem culture, a meristem is a group of undifferentiated plant cells (found at growth tips) which can undergo divisions to form all types of tissues. Generally explant used is shiny dome shaped structure of length less than 0.1mm with one or two pairs of youngest leaf primordia.
In the third organ culture, a specific organ is excised and cultured on a suitable growth nutrient medium under aseptic and controlled physical conditions. Here, the particular organ retains its characteristic structure and features and continue to grow as usual unlike in callus culture where organization of intact tissue is lost. It includes anther culture, pollen culture, culture of embryo, ovary, root, shoot, floral buds, fruit, seed, leaf primordia etc.