Hormone produced during leaf fall is
(a) IAA
(b) ABA
(c) Florigen
(d) Kinetin

Options

A. IAA
B. ABA
C. Florigen
D. Kinetin

Answer

To determine the hormone produced during leaf fall, we can analyze the options provided:

1. **Understanding the Options**:
- (a) IAA (Indole-3-acetic acid): This is a type of auxin, which is primarily involved in promoting growth and is not associated with leaf abscission.
- (b) ABA (Abscisic acid): This hormone is known to play a significant role in the process of leaf abscission and is produced during leaf fall.
- (c) Florigen: This hormone is involved in flowering and is not related to leaf fall.
- (d) Kinetin: This is a type of cytokinin that promotes cell division and growth, and is also not related to leaf abscission.

2. **Analyzing the Role of ABA**:
- ABA is specifically known for its role in inducing leaf abscission. It is produced in higher quantities during the leaf fall process.
- The increase in ABA concentration leads to the loosening of cell walls at the base of the petiole, facilitating the detachment of older leaves.

3. **Conclusion**:
- Since IAA does not promote leaf fall, and both Florigen and Kinetin are unrelated to the process, the only hormone that fits the description of being produced during leaf fall is ABA.

Therefore, the correct answer is **(b) ABA**.