Transpiration is regulated by movements of

Options

A. Guard cells
B. Subsidiary cells
C. Epidermal cells
D. Mesophyll cells

Answer

**Step-by-Step Solution:**

1. **Understanding Transpiration**: Transpiration is the process through which water vapor is lost from the plant, primarily through small openings in the leaves called stomata.

2. **Identifying the Role of Stomata**: Stomata are tiny pores located on the surface of leaves and are essential for gas exchange. They allow water vapor to exit the plant and enable the intake of carbon dioxide for photosynthesis.

3. **Guard Cells Function**: Each stoma is flanked by a pair of specialized cells known as guard cells. These cells are responsible for regulating the opening and closing of the stomatal pores.

4. **Mechanism of Regulation**:
- When guard cells take up water, they become turgid (swollen), causing the stomatal pore to open. This allows for the transpiration process to occur.
- Conversely, when guard cells lose water and become flaccid (shrunken), the stomatal pore closes, thereby reducing or stopping transpiration.

5. **Conclusion**: Given the options provided (guard cells, subsidiary cells, epidermal cells, and mesophyll cells), the correct answer is **guard cells**. They are the primary regulators of transpiration by controlling the stomatal openings.

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