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.
The capacity of a cell/explant to give rise to a whole plant is known as:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Totipotency
The passage states that “This ability of explants to regenerate into whole plants is known as totipotency”.
An explant is any part of a plant taken out and grown in a test tube. Because plant cells are totipotent, a whole new plant can be raised from such a small part, and tissue culture depends on this property.
Option (1) Totipotency — Correct. Totipotency is the capacity of a cell or explant to give rise to a whole plant.
Option (2) Somacloning — Incorrect. Somaclones are the plants produced by micro-propagation, genetically identical to the parent. The word names the plants, not the capacity of a cell.
Option (3) Micro-propagation — Incorrect. Micro-propagation is the method of producing thousands of plants through tissue culture. It makes use of totipotency but is not the capacity itself.
Option (4) Meristem culture — Incorrect. Meristem culture is growing the virus-free meristem in vitro to get healthy plants. It is one application of tissue culture.