Plant hormone causing abscission of leaves, senescence, bud dormancy and inhibition of cell division is

Options

A. IAA
B. Ethylene
C. Cytokinins
D. ABA.

Answer

To answer the question regarding the plant hormone that causes abscission of leaves, senescence, bud dormancy, and inhibition of cell division, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Functions of the Hormones**:
- We need to understand the functions of the four hormones provided in the options: IAA (Indole-3-acetic acid), ethylene, cytokinins, and ABA (Abscisic Acid).

2. **Analyze Each Option**:
- **IAA (Indole-3-acetic acid)**: This is an auxin that primarily promotes cell elongation and is involved in processes like apical dominance, but it does not induce abscission or senescence.
- **Ethylene**: This hormone is known for its role in fruit ripening and can influence senescence, but it does not primarily cause abscission or bud dormancy.
- **Cytokinins**: These hormones promote cell division and growth, and they are not associated with abscission or senescence.
- **ABA (Abscisic Acid)**: This hormone is known as the stress hormone. It plays a crucial role in inducing abscission, promoting senescence, causing bud dormancy, and inhibiting cell division.

3. **Conclude the Correct Answer**:
- Based on the analysis, ABA is the hormone that fits all the criteria mentioned in the question. It is responsible for abscission of leaves, senescence, bud dormancy, and inhibition of cell division.

4. **Final Answer**:
- The plant hormone causing abscission of leaves, senescence, bud dormancy, and inhibition of cell division is **ABA (Abscisic Acid)**.