Tissue Culture & Somatic Hybridization - Practice Questions & MCQ

• Tissue culture is the method of ‘in vitro’ culture of plant or animal cells, tissue or organ – on nutrient medium under aseptic conditions usually in a glass container.
• It was learnt 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.
• 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.
• Each of these plants will be genetically identical to the original plant from which they were grown, i.e., they are somaclones.
• Another important application of the method is the recovery of healthy plants from diseased plants. 
• Although 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.

Somatic Hybridization:

• Single cells can be isolated from plants and after digesting their cell walls to produce naked protoplasts (surrounded by plasma membranes). 
• Isolated protoplasts from two different varieties of plants – each having a desirable character – can be fused to get hybrid protoplasts, which can be further grown to form a new plant. 
• These hybrids are called somatic hybrids while the process is called somatic hybridisation.