One hormone stimulates the closure of stomata and another one influences the swelling of the axis in dicot plants. They are

Options

A. Gibberllins and ethylene
B. Abscisic acid and cytokinins
C. Gibberellins and cytokinins
D. Abscisic acid and ethylene.

Answer

To solve the question, we need to identify the hormones that correspond to the functions described: one that stimulates the closure of stomata and another that influences the swelling of the axis in dicot plants.

### Step-by-Step Solution:

1. **Identify the Hormone for Stomatal Closure**:
- The hormone responsible for stimulating the closure of stomata is **Abscisic Acid (ABA)**.
- Abscisic acid is often referred to as the stress hormone because its levels increase during adverse environmental conditions, such as drought. It helps to reduce water loss by closing the stomata.

2. **Identify the Hormone for Swelling of the Axis**:
- The hormone that influences the swelling of the axis in dicot plants is **Ethylene**.
- Ethylene is known for its role in promoting fruit ripening and is also involved in the triple response of plants, which includes stem elongation, horizontal growth, and swelling of the axis.

3. **Match the Functions with the Options**:
- Now, we need to match our findings with the options provided:
- **Gibberellins and Ethylene**: Gibberellins promote stem elongation and flowering, not stomatal closure.
- **Abscisic Acid and Cytokinins**: Cytokinins promote cell division and delay senescence, not swelling of the axis.
- **Gibberellins and Cytokinins**: Again, gibberellins do not cause stomatal closure.
- **Abscisic Acid and Ethylene**: This option matches our findings perfectly.

4. **Conclusion**:
- The correct answer is **Abscisic Acid and Ethylene**. Abscisic acid stimulates the closure of stomata, while ethylene influences the swelling of the axis in dicot plants.

### Final Answer:
**Abscisic Acid and Ethylene**

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