The ageing of leaves is called

Options

A. Necrosis
B. Senescence
C. Photoperiodism
D. Vernalization

Answer

To solve the question "The ageing of leaves is called," we will analyze the options provided and determine the correct answer step by step.

### Step-by-Step Solution:

1. **Understanding the Options**:
- We have four options:
- A) Necrosis
- B) Senescence
- C) Photoperiodism
- D) Vernalization

2. **Analyzing Option A: Necrosis**:
- Necrosis refers to the death of plant tissue due to injury or disease. It is not related to the natural aging process of leaves. Therefore, this option is incorrect.

3. **Analyzing Option B: Senescence**:
- Senescence is defined as the process of natural aging in plants. It involves the gradual deterioration of functional activities in plant parts, including leaves. This is a normal process and not caused by any disease. As cells age, they lose their ability to grow, divide, and repair, leading to their eventual death. This option aligns perfectly with the question, making it the correct answer.

4. **Analyzing Option C: Photoperiodism**:
- Photoperiodism is the response of plants to the length of day and night, affecting their developmental processes such as flowering. It is unrelated to the aging of leaves, so this option is incorrect.

5. **Analyzing Option D: Vernalization**:
- Vernalization refers to the process of inducing flowering in plants through exposure to cold temperatures. This is a specific method of flowering induction and does not pertain to the aging of leaves. Thus, this option is also incorrect.

6. **Conclusion**:
- After analyzing all the options, we conclude that the correct answer to the question "The ageing of leaves is called" is **B) Senescence**.

### Final Answer:
The ageing of leaves is called **Senescence**.