Select an incorrect statement about stomatal opening

Options

A. With a decline in guard cell solutes stomata close.
B. Accumulation of large amounts of potassium K+ in guard cells is electrically balanced by the uptake of negativelycharged ions - chloride and malate
C. High amount of malate in guard cells of open stomata accumulates by hydrolysis of glycogen
D. Opening and closing of stomata is controlled by osmotic movement of water in or out of the guard cells

Answer

To solve the question of selecting an incorrect statement about stomatal opening, we will analyze each of the provided statements one by one.

### Step-by-Step Solution:

1. **Understanding Stomata and Guard Cells**:
- Stomata are small openings on the surfaces of leaves that facilitate gas exchange and transpiration.
- Each stoma is surrounded by a pair of guard cells that regulate its opening and closing based on turgidity, which is influenced by osmotic pressure and solute concentration within the guard cells.

2. **Analyzing the First Statement**:
- **Statement**: "With a decline in guard cell solutes, stomata close."
- **Analysis**: When guard cells lose solutes, their turgor pressure decreases, leading to stomatal closure. This statement is true.

3. **Analyzing the Second Statement**:
- **Statement**: "Accumulation of large amounts of potassium in guard cells is electrically balanced by uptake of negatively charged ions chloride and malate."
- **Analysis**: This statement is accurate. Potassium ions (K+) are positively charged and their accumulation in guard cells is balanced by negatively charged ions like chloride (Cl-) and malate (an organic anion). This statement is true.

4. **Analyzing the Third Statement**:
- **Statement**: "High amount of malate in guard cells of open stomata accumulates by hydrolysis of glycogen."
- **Analysis**: This statement is incorrect. The accumulation of malate in guard cells occurs due to the hydrolysis of glucose, not glycogen. Therefore, this statement is false.

5. **Analyzing the Fourth Statement**:
- **Statement**: "Opening and closing of stomata is controlled by osmotic movement of water in or out of the guard cells."
- **Analysis**: This statement is true. The turgidity of guard cells, which determines the opening and closing of stomata, is indeed controlled by the osmotic movement of water.

6. **Conclusion**:
- Based on the analysis, the incorrect statement about stomatal opening is the third statement: "High amount of malate in guard cells of open stomata accumulates by hydrolysis of glycogen."

### Final Answer:
The incorrect statement about stomatal opening is: **"High amount of malate in guard cells of open stomata accumulates by hydrolysis of glycogen."**

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