The hormone that controls closure of stomata in response to water stress is

Options

A. auxins
B. gibberellins
C. cytokinin
D. abscisic acid

Answer

**Step-by-Step Text Solution:**

1. **Understanding the Question**: The question asks for the hormone responsible for the closure of stomata in response to water stress in plants.

2. **Identifying the Options**: The options provided are:
- Auxin
- Gibberellin
- Cytokinin
- Abscisic Acid

3. **Analyzing Each Option**:
- **Auxin**: Primarily involved in cell elongation and growth responses.
- **Gibberellin**: Promotes stem elongation, seed germination, and flowering.
- **Cytokinin**: Promotes cell division and growth, particularly in roots and shoots.
- **Abscisic Acid (ABA)**: Known as the stress hormone, it plays a crucial role in plant responses to stress conditions such as drought.

4. **Connecting Abscisic Acid to Stomatal Closure**: Abscisic acid is specifically known to stimulate the closure of stomata when the plant experiences water stress. This action helps to reduce water loss through transpiration.

5. **Conclusion**: The hormone that controls the closure of stomata in response to water stress is **Abscisic Acid**.

**Final Answer**: Abscisic Acid

---