Stomata opening and closing is due to

Options

A. Change in turgidity of guard cell
B. Cellulose microfibrils of guard cells are oriented radially
C. The inner wall of each guard cell is thick and less elastic
D. All the above

Answer

**Step-by-Step Solution:**

1. **Understanding Stomata**: Stomata are small openings on the surface of leaves that facilitate gas exchange (CO2 in and O2 out) and transpiration (water vapor loss).

2. **Role of Guard Cells**: Each stoma is surrounded by a pair of guard cells. The turgidity (internal water pressure) of these guard cells is crucial for the opening and closing of the stomata.

3. **Turgidity Changes**:
- When guard cells take up water, they become turgid (swollen), causing them to bend and open the stomata.
- Conversely, when guard cells lose water, they become flaccid (less swollen), leading to the closing of the stomata.

4. **Cellulose Microfibrils Orientation**: The cellulose microfibrils in the guard cells are oriented radially. This arrangement allows the guard cells to expand more in the direction of the stomatal opening when they become turgid.

5. **Inner Wall Structure of Guard Cells**: The inner wall of guard cells is thicker and less elastic compared to the outer wall. This structural difference helps facilitate the opening and closing mechanism of the stomata.

6. **Conclusion**: All the factors mentioned (change in turgidity of guard cells, orientation of cellulose microfibrils, and the structure of the inner wall of guard cells) contribute to the opening and closing of stomata. Therefore, the correct answer is "all of the above."

**Final Answer**: The opening and closing of stomata is due to: **All of the above**.

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