Question

Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R).
Assertion (A) : In mango for obtaining good flowering one must stop irrigation at least 2-3 months before the flowering period
Reason (R) : Water stress is not a mechanism encouraging the formation of mango flowering but it does affect vegetative growth
In light of the above statements, choose the most appropriate answer from the options given below.

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A).
• B. Both (A) and (R) are correct but (R) is NOT the correct explanation of (A).
• C. (A) is correct but (R) is not correct.
• D. (A) is not correct but (R) is correct.

Hint:

In mango, a period of stress (like mild water stress) can shift the plant's focus from growing leaves/stems to producing flowers.
Assertion (A): Stopping irrigation creates this stress.
Reason (R): Water stress stops leafy growth. This stop in leafy growth is what helps trigger flowering. So, the reason explains the assertion.

Answer 1

The Correct Option is A

Assertion (A): In mango for obtaining good flowering one must stop irrigation at least 2-3 months before the flowering period. This statement is true. Withholding irrigation for a period before the expected flowering time is a common horticultural practice in mango cultivation. This induces a mild water stress, which helps to check vegetative growth and promote the differentiation of vegetative buds into floral buds. Reason (R): Water stress is not a mechanism encouraging the formation of mango flowering but it does affect vegetative growth. This statement, when interpreted in a specific physiological context, can be considered true. While water stress itself might not directly trigger the biochemical pathways for flower formation in a positive stimulatory sense, its primary and well-established effect is to suppress or check vigorous vegetative growth. By reducing vegetative flushes, the tree can accumulate carbohydrates and alter its hormonal balance (e.g., C:N ratio, gibberellin levels decrease, abscisic acid might increase), creating conditions that are conducive to flower bud initiation and development. So, its role in encouraging flowering is often indirect, mediated by its direct impact on ceasing vegetative growth. Is (R) the correct explanation of (A)? Yes, (R) explains (A). Stopping irrigation (Assertion A) leads to water stress. This water stress, as stated in Reason R, affects (checks) vegetative growth. The cessation or reduction of vegetative growth is a key prerequisite for the plant to shift its resources and physiological state towards reproductive development (flowering). Therefore, the effect of water stress on vegetative growth is the mechanism through which withholding irrigation promotes flowering. Both statements are considered correct in this context, and (R) provides the physiological basis for the practice described in (A). Both (A) and (R) are correct and (R) is the correct explanation of (A).