PLANT TISSUE CULTURE

In plant tissue culture, a very small tissue from a parent plant called as explant is placed in a test tube in a nutrient medium. The tissue may be taken from any part of the plant, that is, root, stem, leaf, anther or embryo. This is because all plant cells possess totipotency meaning a single cell can give rise to an entire plant. The nutrient medium used in tissue culture consists of sucrose apart from mineral salts and vitamins. Plant hormones such as auxins are used to help growth and cell division. The solidifying agent, agar-agar makes the medium semi solid otherwise the culture is done in suspension. The inoculated tubes are kept in an incubator to maintain sterile conditions and controlled temperature and light. After 2-3 weeks of incubation an irregular mass of cells called callus develops, which on sub culturing gives rise to small plantlets. These are potted and maintained in a green house and subsequently transferred to the field. PTC is aimed at engineering crop plants for good traits.