Leaf ageing is retarded by

Options

A. cytokinin
B. ethylene
C. auxin
D. abscisic acid

Answer

**Step-by-Step Solution:**

1. **Understanding Leaf Aging**: Leaf aging in plants is referred to as senescence. This process involves the gradual deterioration of leaf cells and ultimately leads to leaf drop.

2. **Identifying Plant Hormones**: The question provides four hormones: Cytokinin, Ethylene, Auxin, and Abscisic Acid. We need to determine which of these hormones is responsible for retarding or delaying the aging process of leaves.

3. **Analyzing Each Hormone**:
- **Cytokinin**: This hormone is primarily involved in promoting cell division and delaying senescence. It helps in nutrient mobilization and can counteract the effects of aging in leaves.
- **Ethylene**: This is a gaseous hormone known for its role in fruit ripening and promoting senescence rather than delaying it.
- **Auxin**: This hormone is mainly responsible for apical dominance and does not play a significant role in delaying leaf aging.
- **Abscisic Acid (ABA)**: This hormone is involved in stress responses and can promote leaf senescence rather than delay it.

4. **Conclusion**: Among the hormones listed, Cytokinin is the one that retards leaf aging by delaying the senescence process. Therefore, the correct answer is Cytokinin.

**Final Answer**: Leaf ageing is retarded by Cytokinin.

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