Read the paragraph and answer the questions:
Plant tissue culture is based on the special property of plant cells to generate a whole plant, called totipotency. The plant part used in tissue culture is called explant. The nutrient medium provides a carbon sources such as sucrose. inorganic salts, vitamins, amino acids and growth regulators like auxins cytokinins etc. Propagation of thousands of plants in very short duration through tissue culture is called micropropagation. Each of these plants will be genetically identical to the original plant i.e., they are somaclones. Another application of tissue culture is to recover virus free plants, from the infected ones. The apical or axillary meristem, which is free of virus, is removed and cultured in-vitro to obtain virus-free plants. Scientists have succeeded in culturing meristems of sugarcane, banana, potato etc. Scientists have isolated single cells from plants and after digesting their cell walls, the protoplasts were isolated. Protoplasts from two different varieties of plants - each having a desirable character - are fused to get hybrid protoplasts. These hybrid protoplasts are called somatic hybrids and the process is called somatic hybridisation. Somatic hybrids are further grown to form a new plant. Protoplast of tomato is fused with that of potato, to form new hybrid plants called Pomato. Pomato unfortunately did not have all the desired combination of the two plants.
The explant used in tissue culture must show :
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Totipotency
An explant is the part of a plant taken out and grown in tissue culture. It works only because plant cells have totipotency: the capacity to generate a whole plant, as the passage says.
Option (1) Encystation — Incorrect. Encystation is the forming of a protective cyst by some protists, such as Amoeba, in bad conditions.
Option (2) Sporulation — Incorrect. Sporulation is the forming of spores, a method of reproduction.
Option (3) Dioecy — Incorrect. Dioecy means having male and female flowers on separate plants.
Option (4) Totipotency — Correct. Every cell of the explant can grow into a complete plant.
Note: The passage is taken from NCERT. NTA has put lines of the NCERT text together to make it. Most CUET (UG) questions come straight from NCERT, so study the book line by line, including figures and their titles.