Photoperiodic stimulus is perceived by
(a) Meristematic cells
(b) Leaves
(c) Flowers
(d) Seeds

Options

A. Meristematic cells
B. Leaves
C. Flowers
D. Seeds

Answer

To solve the question "Photoperiodic stimulus is perceived by," we will analyze each option step by step.

### Step 1: Understand Photoperiodism
Photoperiodism is the physiological reaction of organisms to the length of day or night. In plants, it primarily influences flowering and other developmental processes based on the relative lengths of light (day) and darkness (night).

**Hint:** Remember that photoperiodism is related to how plants respond to light and darkness.

### Step 2: Analyze Each Option
- **(a) Meristematic cells:** These are actively dividing cells found in the growing regions of plants (like tips of roots and shoots). They are not primarily responsible for perceiving light stimuli.

- **(b) Leaves:** Leaves are the main site for light absorption in plants. They contain chlorophyll and other pigments that can detect light changes. In flowering plants, leaves are known to perceive photoperiodic stimuli through photoreceptors like phytochrome.

- **(c) Flowers:** While flowers are the result of photoperiodic responses, they do not perceive the light stimulus themselves. They are the end product of the process initiated by the perception of light by other parts of the plant.

- **(d) Seeds:** Seeds are dormant structures that do not perceive light. They may respond to environmental conditions once germination begins, but they do not perceive photoperiodic stimuli.

### Step 3: Conclusion
Based on the analysis, the correct answer is **(b) Leaves**. Leaves are responsible for perceiving the photoperiodic stimulus, which influences flowering and other developmental processes in plants.

**Final Answer:** (b) Leaves