Question

Write a note on callus culture.

Answer 1

Callus varies considerably in appearance and texture, ranging from hard nodular cell masses to friable soft ones. They maybe white or creamish, orange, green either in whole or part as a result of chloroplast development. The shape of individual cells within the callus mass ranges from the near spherical or markedly elongated.

A typical unorganized plant callus initiated from a new explants or piece of previously initiated calli has three stages of development.

1. The induction of cell division.

2. A period of active cell division during which differentiated cells lose specialized features they may have acquired and become de–differentiated. Cell division usually occurs in the outer layer of the explants.

3. Period when cell division slows down on ceases and when within the callus, there is increasing cellular differentiat

Callus culturing is performed in the dark while light can be encourage the differentiation of the callus. At the time of long term culture, the culture may loss the requirement for cytokinin and auxins. Manipulation of the auxins to cytokinin ratio in the medium can leads to the development of shoots, roots or somatic embryos from which the plant can be subsequently produced.