Which ions are responsible for stomatal movement

Options

A. Ferric
B. Zinc
C. Potassium
D. Sodium

Answer

**Step-by-Step Solution:**

1. **Understanding Stomatal Movement:**
- 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 water regulation.

2. **Role of Guard Cells:**
- Stomatal movement is controlled by guard cells that surround each stoma. These cells can change shape to either open or close the stomatal pore.

3. **Ions Involved in Stomatal Movement:**
- The primary ions responsible for the movement of stomata are potassium ions (K+). When potassium ions enter the guard cells, they cause an increase in osmotic pressure.

4. **Water Uptake:**
- The influx of potassium ions into the guard cells leads to the uptake of water. This is because the increase in potassium concentration inside the guard cells creates a gradient that draws water in through osmosis.

5. **Turgidity and Stomatal Opening:**
- As the guard cells take up water, they swell and become turgid. This turgidity causes the guard cells to bow outward, leading to the opening of the stomatal pore.

6. **Other Ions:**
- Along with potassium ions, chloride ions (Cl-) also play a role in stomatal opening. Additionally, hydrogen ions (H+) are expelled from the guard cells during this process.

7. **Conclusion:**
- Therefore, the correct answer to the question is potassium ions (K+), as they are the primary ions responsible for the opening of stomata.

**Final Answer:**
- The ions responsible for stomatal movement are potassium ions (K+).

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