Question

In tissue culture, the term callus refers to

Answer 1

Tissue culture is the technique of growing plant cells, tissues or organs in a sterile culture medium under controlled environmental conditions. The culture media contains appropriate concentrations of all necessary nutrients and growth hormones such as auxins, cytokinins, etc.

A callus is a mass of irregular, undifferentiated, parenchymatous and totipotent cells. These cells have the ability to divide and differentiate to form an entire organism. It is formed in culture media due to active mitotic divisions of the cells of the explant (plant part, tissue or cell being cultured).

A balanced concentration of auxins and cytokinins in the culture media induces the cells of the explant to actively divide and form a callus. The callus is made up of living cells which possess the ability to divide further.