An important factor in stomata opening is

Options

A. hormone content of cells
B. protein content of cells
C. chlorophyll content of cells
D. shape of guard cells

Answer

**Step-by-Step Solution:**

1. **Understanding Stomata Function**: Stomata are small openings on the surface of leaves that allow for gas exchange (CO2 in, O2 out) and transpiration (water vapor loss). The opening and closing of stomata are crucial for plant health and photosynthesis.

2. **Identifying Factors Affecting Stomata Opening**: Several factors influence the opening and closing of stomata, including:
- Light: Stomata generally open in the presence of light.
- Water Content: The turgor pressure in guard cells, which is influenced by water availability, affects stomata opening.
- Temperature: Higher temperatures can increase the rate of transpiration and influence stomata behavior.
- Mineral Elements: Nutrient availability can also affect stomatal function.

3. **Focusing on Guard Cells**: The guard cells are specialized cells that flank each stoma. Their shape and turgor pressure determine the size of the stomatal opening. When guard cells take up water, they swell and curve, causing the stomata to open.

4. **Conclusion**: Among the given options (hormone content, protein content, chlorophyll content, shape of guard cells), the shape of the guard cells is the most important factor in stomata opening. This is because the guard cells' ability to change shape directly controls the size of the stomatal opening.

5. **Final Answer**: The correct answer is **D) Shape of the guard cells**.

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