Ethylene is highly effective in

Options

A. Root growth and root hair formation
B. Abscission of palnts organs
C. Apical hook formation in dicot seedlings
D. Fruit ripening

Answer

**Step-by-Step Solution:**

1. **Understanding Ethylene**: Ethylene is a plant hormone that plays a significant role in various physiological processes in plants. It is a gaseous hormone that influences growth and development.

2. **Analyzing the Options**:
- **Option A**: Root growth and root hair formation - While ethylene does play a role in root development, it is not primarily known for this function.
- **Option B**: Abscission of plant organs - Ethylene does influence the abscission process (the shedding of leaves, flowers, or fruits), but it is not the most notable effect.
- **Option C**: Apical hook formation in dicot seedlings - Ethylene is involved in this process, but it is not the primary function associated with ethylene.
- **Option D**: Fruit ripening - Ethylene is highly effective in promoting fruit ripening, enhancing the respiration rate, and is known as a "respiratory climacteric."

3. **Conclusion**: Based on the analysis, ethylene is most notably effective in fruit ripening. This process involves an increase in respiration, which is a characteristic feature of climacteric fruits.

4. **Final Answer**: Therefore, the correct answer is **Option D: Fruit ripening**.

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