Site of perception of light/dark duration is/are

Options

A. Shoot apex
B. Root Apex
C. Permanent tissue
D. More than one option is correct

Answer

To answer the question "Site of perception of light/dark duration is/are," we will analyze the options provided and understand the concept of photoperiodism in plants.

### Step-by-Step Solution:

1. **Understanding Photoperiodism**:
- Photoperiodism refers to the physiological reaction of organisms to the length of day or night. In plants, it is crucial for determining flowering time and other developmental processes.
- The perception of light and dark duration is essential for plants to respond appropriately to their environment.

2. **Identifying the Site of Perception**:
- The primary site where plants perceive light and dark durations is the leaves.
- Leaves contain specialized tissues that respond to light, which are involved in the synthesis of hormones that regulate flowering.

3. **Role of Permanent Tissues**:
- Permanent tissues in the leaves, such as parenchyma, chlorenchyma, and sclerenchyma, play a significant role in this perception.
- These tissues are responsible for various functions, including photosynthesis, storage, and structural support, which are essential for the plant's response to light.

4. **Evaluating the Options**:
- **Shoot Apex**: While the shoot apex is involved in growth and development, it is not the primary site for light/dark perception.
- **Root Apex**: The root apex is primarily involved in growth and nutrient absorption and does not perceive light.
- **Permanent Tissue**: This is the correct answer as it includes the leaf tissues that perceive light and dark durations.
- **More than one option is correct**: This is incorrect as only permanent tissue is the correct answer.

5. **Conclusion**:
- The correct answer to the question is **Permanent Tissue**.

### Final Answer:
The site of perception of light/dark duration is **Permanent Tissue**.