UPSC Civil Services Model Paper 8

Tissue culture:
It was learned by scientists , during the 1950s , that whole plants could be regenerated from explants , i.e., any part of a plant taken out and grown in a test tube, under sterile conditions in special nutrient media.
This capacity to generate a whole plant from any cell/explant is called totipotency.
Hence, Statement 2 is incorrect.
It is important to stress here that the nutrient medium must provide a carbon source such as sucrose and also inorganic salts, vitamins, amino acids, and growth regulators like auxins, cytokinins, etc.
By application of these methods, it is possible to achieve propagation of a large number of plants in very short durations.
This method of producing thousands of plants through tissue culture is called micropropagation . Hence, Statement 1 is incorrect.
Each of these plants will be genetically identical to the original plant from which they were grown, i.e. they are some clones .
Many important food plants like tomato, banana, apple, etc. have been produced on a commercial scale using this method.
Another important application of the method is the recovery of healthy plants from diseased plants.
Even if the plant is infected with a virus , the meristem ( apical and axillary) is free of virus.
Hence, one can remove the meristem and grow it in vitro to obtain virus-free plants.
Scientists have succeeded in culturing meristems of banana, sugarcane, potato, etc.