The site of perception of photoperiod is

Options

A. leaves
B. flowers
C. shoot apices
D. root apices

Answer

To answer the question "The site of perception of photoperiod is," we will follow these steps:

### Step 1: Understand Photoperiodism
Photoperiodism is the response of plants to the lengths of day and night. It plays a crucial role in regulating various developmental processes in plants, including flowering.

### Step 2: Identify the Key Components
Plants respond to light and dark periods, which are essential for determining their growth patterns. The main types of photoperiodic responses are categorized into:
- Long-day plants
- Short-day plants
- Day-neutral plants

### Step 3: Determine the Site of Perception
The site where plants perceive photoperiod (the duration of light and darkness) is primarily the leaves. This is where the plant detects the light signals that trigger hormonal changes necessary for flowering.

### Step 4: Hormonal Response
Once the leaves perceive the photoperiod, they produce a hormonal substance that is responsible for initiating the flowering process. This hormone then travels from the leaves to the shoot apex, where flowering occurs.

### Step 5: Conclusion
Thus, the correct answer to the question is that the site of perception of photoperiod is the **leaves**.

### Final Answer
The site of perception of photoperiod is **leaves**.

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