Read the passage and answer the following questions:
The Green Revolution successfully increased food production by threefold, but it still couldn't meet the demand of the growing human population. The increased yields were partly due to the use of improved crop varieties, but mainly due to better management practices and the use of agrochemicals such as fertilisers and pesticides. However, farmers in the developing world often find agrochemicals too expensive, and further improvements in yield using conventional breeding methods become challenging. To address the limitations of traditional breeding techniques, scientists developed a technology called tissue culture. Tissue culture involves the regeneration of whole plants from small plant parts (explants) that are grown in a controlled environment, such as a test tube, with specific nutrient media. This ability of explants to regenerate into whole plants is known as totipotency. The nutrient medium used in tissue culture contains carbon sources like sucrose, inorganic salts, vitamins, amino acids, and growth regulators like auxins and cytokinins. By utilising tissue culture techniques, a large number of plants can be propagated rapidly and efficiently, a process known as micro-propagation. These plants are genetically identical to the original plant from which the explants were obtained, making them somaclones. Many important food plants, such as tomato, banana, and apple, have been commercially produced using tissue culture. Another significant application of tissue culture is the recovery of healthy plants from diseased ones. Even if a plant is infected with a virus, the meristem (apical and axillary) regions remain free of the virus. Scientists can remove the virus-free meristem and grow it in vitro to obtain virus-free plants.
Choose the correct statements about somatic hybridisation from the following:
A. Naked protoplasts are isolated from single plant cells after digesting their cell walls.
B. Isolated protoplasts from two different varieties of plants can be fused to get hybrid protoplasts.
C. Pomato was formed by fusing the protoplasts of tomato and potato.
D. The hybrids formed by fusing protoplasts are called somatic hybrids, and the process is called micro-propagation.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → A, B and C only
Somatic hybridisation is another use of plant tissue culture. Cells of two plants are joined directly, without sexual reproduction, to get a plant with the characters of both.
A. Naked protoplasts are isolated from single plant cells after digesting their cell walls. — True. Once the cell wall is digested, the cell is left as a protoplast surrounded only by its plasma membrane.
B. Isolated protoplasts from two different varieties of plants can be fused to get hybrid protoplasts. — True. Each variety has a desirable character, and the hybrid protoplast can be grown into a new plant.
C. Pomato was formed by fusing the protoplasts of tomato and potato. — True. The fused protoplasts of tomato and potato gave the pomato, though it did not have all the characters needed for commercial use.
D. The hybrids formed by fusing protoplasts are called somatic hybrids, and the process is called micro-propagation. — False. The hybrids are somatic hybrids, but the process is called somatic hybridisation. Micro-propagation is the production of thousands of identical plants through tissue culture.
NCERT Extract:
Biotechnological Applications in Agriculture – “Scientists have even isolated single cells from plants and after digesting their cell walls have been able to isolate 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. Imagine a situation when a protoplast of tomato is fused with that of potato, and then they are grown – to form new hybrid plants combining tomato and potato characteristics. Well, this has been achieved – resulting in formation of pomato; unfortunately this plant did not have all the desired combination of characteristics for its commercial utilisation.”