What is the difference between meristem culture and callus culture?

Meristem culture involves culturing of differentiated cells; whereas callus culture involves culturing of undifferentiated cells.

A meristem consists of actively dividing cells. The cells formed by cell division gets differentiated into different types of cells which give rise to different tissues in the mature organ, developing from that meristem.

Meristem culture mainly involves culturing a bud in culture medium under aseptic conditions. The bud develops into shoot in the culture as the meristem already has the cells differentiated to give rise to different tissues of shoot.

The callus is mass of undifferentiated cells. The callus culture involves the differentiation of cells and consequently growth of differentiated cells into different organs of the plant.

The differentiation of the callus depends upon the proportion of different growth hormones.

The callus obtained from tobacco plant pith may differentiate into root cell only if the medium contains auxins only and develops into shoot if the medium contains cytokinins.

The callus may develop into complete plant if the medium contains balnced amount of auxins and cytokinins as some cell will differentiate into root cells and other into shoot tissue.

Thus the type of organ developing from meristem culture is predetermined depending upon the meristem taken for culture. In callus culture, the type of organ developing can be controlled by regulating the proportion of growth hormones like auxinx and cytokinins in the culture medium.

The callus obtained from stem tissue of a plant can be made to develop into root and vice versa by regulating the proportion of growth hormones.

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