Senescence of leaves can be delayed and shelf life of fruits can be increased by the spray of

Options

A. Cytokinins
B. Gibberellins
C. auxins and Ethylene
D. ABA

Answer

**Step-by-Step Solution:**

1. **Understanding Senescence and Shelf Life**:
- Senescence refers to the aging process in plants, particularly in leaves, which leads to their eventual death and fall.
- Shelf life of fruits pertains to the duration they remain fresh and consumable after being harvested.

2. **Role of Plant Hormones**:
- Plant hormones are chemical substances that regulate various physiological processes in plants, including growth, development, and aging.

3. **Identifying the Relevant Hormone**:
- The hormone that is known to delay senescence in leaves and extend the shelf life of fruits is called **cytokinin**.

4. **Mechanism of Action**:
- Cytokinins promote nutrient mobilization within the plant. This means they help in the distribution of nutrients to various parts of the plant, including leaves and fruits.
- By enhancing nutrient availability, cytokinins delay the aging process of leaves, preventing them from falling off prematurely.

5. **Effect on Fruits**:
- When fruits are harvested, spraying them with cytokinins helps retain chlorophyll, the green pigment crucial for photosynthesis.
- The retention of chlorophyll contributes to maintaining the freshness and quality of the fruits, thereby increasing their shelf life.

6. **Conclusion**:
- Therefore, the answer to the question is that senescence of leaves can be delayed and the shelf life of fruits can be increased by the spray of **cytokinin**.

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