Which one of the following is an anti transpirant and a stress hormone

Options

A. IAA
B. ABA
C. NAA
D. GA

Answer

To answer the question "Which one of the following is an anti-transpirant and a stress hormone?" we need to analyze the options provided: IAA, IBA, NAA, and GA.

### Step-by-Step Solution:

1. **Understanding Anti-Transpirants**:
- Anti-transpirants are substances that reduce or inhibit the process of transpiration in plants. Transpiration is the process where water is lost from the plant in the form of vapor, primarily through small openings called stomata.

2. **Identifying the Hormones**:
- **IAA (Indole-3-Acetic Acid)**: This is a natural plant growth hormone involved in processes like apical dominance and fruit development. It does not function as an anti-transpirant.
- **IBA (Indole-3-Butyric Acid)**: Similar to IAA, IBA is also a plant growth regulator but does not have anti-transpirant properties.
- **NAA (Naphthalene Acetic Acid)**: This is a synthetic auxin that promotes growth and is involved in apical dominance. It does not act as an anti-transpirant.
- **GA (Gibberellins)**: These hormones are primarily involved in promoting stem elongation and other growth processes. They do not inhibit transpiration.

3. **Identifying the Correct Hormone**:
- **ABA (Abscisic Acid)**: Although not listed in the options, it is important to note that ABA is known as a stress hormone. It plays a crucial role in plant responses to stress, particularly drought. It works by closing the stomata to reduce water loss, thus acting as an anti-transpirant.

4. **Conclusion**:
- Among the options provided, none directly fit the criteria of being both an anti-transpirant and a stress hormone. However, if we consider the context of the question, the closest answer based on the characteristics discussed is **ABA**, which is not listed but is the correct answer in the context of plant hormones.

### Final Answer:
None of the options (IAA, IBA, NAA, GA) are both anti-transpirants and stress hormones. The correct answer should be **ABA (Abscisic Acid)**, which is not listed.