Which of the following is not included in triple response shown by ethylene ?

Options

A. Horizontal growth of seedling
B. Swelling of the Axis
C. Apical hook formation in dicot seedling
D. Promotion of male flower

Answer

To solve the question regarding the triple response shown by ethylene, we will analyze each option provided and determine which one is not included in the triple response.

### Step-by-Step Solution:

1. **Understanding Ethylene**: Ethylene is a gaseous plant hormone known for its role in various plant processes, including fruit ripening and growth responses.

2. **Identifying the Triple Response**: The triple response to ethylene in plants typically consists of:
- **Horizontal Growth of Seedling**: This refers to the growth of the seedling in a horizontal direction rather than vertical, which is a response to the presence of ethylene.
- **Swelling of the Axis**: This involves the thickening or swelling of the plant stem or axis, which is also a characteristic response to ethylene.
- **Apical Hook Formation in Dicot Seedlings**: This is the formation of a hook at the top of dicot seedlings, which helps them navigate through the soil.

3. **Evaluating the Options**:
- **Option 1: Horizontal Growth of Seedling** - This is part of the triple response.
- **Option 2: Swelling of the Axis** - This is also part of the triple response.
- **Option 3: Apical Hook Formation in Dicot Seedling** - This is included in the triple response.
- **Option 4: Promotion of Male Flower** - This is not part of the triple response.

4. **Conclusion**: The option that is not included in the triple response shown by ethylene is the promotion of male flowers.

### Final Answer:
**Promotion of male flower** is not included in the triple response shown by ethylene.

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