Which one o f the following plant hormone (phytomone ) Is know as a stress hormone

Options

A. lndole acetic acid
B. Abscissic acid
C. Ethylene
D. `GA_3 `

Answer

### Step-by-Step Text Solution:

1. **Understanding Plant Hormones**: Plant hormones, also known as phytohormones, are chemical substances that regulate various physiological processes in plants. They play crucial roles in growth, development, and responses to environmental stimuli.

2. **Identifying the Options**: The question provides four options regarding plant hormones:
- Indole Acetic Acid (IAA)
- Abscisic Acid (ABA)
- Ethylene
- Gibberellin (GA)

3. **Analyzing Indole Acetic Acid (IAA)**: Indole Acetic Acid is a type of auxin. Auxins are primarily involved in promoting growth, particularly in the elongation of cells, and they play a role in the development of fruits and leaves. They are not classified as stress hormones.

4. **Analyzing Abscisic Acid (ABA)**: Abscisic Acid is known as the stress hormone. It helps plants cope with various stress conditions, such as drought and extreme temperatures. ABA also plays a role in maintaining seed dormancy, allowing seeds to withstand unfavorable conditions until they can germinate.

5. **Analyzing Ethylene**: Ethylene is a gaseous hormone that regulates processes such as fruit ripening and plant growth. While it is important for plant development, it is not specifically known as a stress hormone.

6. **Analyzing Gibberellin (GA)**: Gibberellins are involved in promoting stem elongation, seed germination, and flowering. They are not classified as stress hormones.

7. **Conclusion**: Based on the analysis, the plant hormone known as the stress hormone is **Abscisic Acid (ABA)**.

### Final Answer:
**Abscisic Acid (ABA)** is known as the stress hormone in plants.

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