A growth inhibitor responsible for stomatal closure is

Options

A. Zeatin
B. Abscisic acid
C. Ethylene
D. `GA_(3)`

Answer

**Step-by-Step Solution:**

1. **Identify the Question**: The question asks for a growth inhibitor responsible for stomatal closure.

2. **Understand the Options**: The options given are:
- Zeatin
- Abscisic Acid
- Ethylene
- GA3 (Gibberellic Acid)

3. **Analyze Each Option**:
- **Zeatin**: This is a form of cytokinin, which is known to promote growth and is not involved in stomatal closure. Therefore, it can be eliminated.
- **Abscisic Acid**: This hormone is known as a growth inhibitor and plays a crucial role in stomatal closure, especially under stress conditions. This option appears to be the correct answer.
- **Ethylene**: While it is a growth inhibitor, its primary function is in fruit ripening and it does not directly cause stomatal closure. Thus, it can be eliminated.
- **GA3 (Gibberellic Acid)**: This hormone is primarily involved in breaking seed dormancy and promoting growth, but it does not influence stomatal closure. Therefore, this option can also be eliminated.

4. **Conclude the Answer**: Based on the analysis, the only hormone that is a growth inhibitor and responsible for stomatal closure is **Abscisic Acid**.

5. **Final Answer**: The growth inhibitor responsible for stomatal closure is **Abscisic Acid**.

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