Question

Assertion: Auxin promotes apical dominance by suppressing the activity of lateral buds.
Reason: In moriculture periodic pruning of shoot tips is done to make mulberry plants bushy.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
C. Assertion is correct but Reason is incorrect
D. Both Assertion and Reason are incorrect

Answer 1

Hint: The referred chemical substance is responsible for cell elongation. While pruning helps grow the plant in a desirable shape, the referred hormone helps it grow in the desired direction. The above-mentioned points are synchronous with each other.

Complete answer:
> Auxin is a plant hormone, chemical substances produced in the plants. This hormone is produced in the stem tip that helps in the promotion of cell elongation. The other functions of auxins include phototropism and geotropism. These hormones move from the lighter side of the plant to the darker side so that the cells on the darker side can grow larger than corresponding cells on the lighter side of the plant. Moriculture is defined as the practice of rearing mulberry trees in order to raise silk-producing silkworms. This is because silkworms feed on mulberry leaves.
> Auxin is produced by the shoot tip. They work as the growth promoter for apical buds. Further, they inhibit the growth of lateral buds. When we remove the terminal bud, this will help the nearest axillary buds to grow faster and the plant to branch out rapidly. Pruning is done in mulberry plants. Pruning helps in removing the apical dominance and causes more branching of the main body of the plant.

So, the correct answer is an option (A).

Note: Other than that, auxins are also responsible for cell elongation and cell differentiation. Therefore they are the regulating factors in root formation, fruit development, apical dominance, and abscission. Besides, the cultivation of silkworms is called sericulture.