With respect to photoperiodism, site of perception of light/ dark duration is

Options

A. Root apex
B. Shoot apex
C. Flower
D. Leaf

Answer

To solve the question regarding the site of perception of light/dark duration in photoperiodism, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Photoperiodism**:
- Photoperiodism refers to the physiological reaction of organisms to the length of day or night. In plants, it primarily affects flowering and other developmental processes.

2. **Identify the Types of Plants**:
- Plants can be categorized based on their response to photoperiod:
- **Long Day Plants**: These plants require longer daylight hours to flower.
- **Short Day Plants**: These plants require longer periods of darkness to flower.
- **Day Neutral Plants**: These plants are not affected by the length of day or night.

3. **Determine the Site of Perception**:
- The question asks for the site where plants perceive light and dark duration.
- In plants, the primary site for this perception is the leaves. The leaves contain photoreceptors that detect light and dark periods.

4. **Conclusion**:
- Based on the understanding that leaves are responsible for perceiving light and dark duration, we conclude that the correct answer to the question is **leaves**.

### Final Answer:
The site of perception of light/dark duration in photoperiodism is the **leaves**.

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