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 determine the incorrect statement about stomatal opening, we need to analyze each of the provided statements regarding the function and behavior of guard cells.

### Step-by-Step Solution:

1. **Understanding Guard Cells and Stomatal Opening**:
- Guard cells are specialized cells that surround the stomata (pores) on the leaf surface. They regulate the opening and closing of the stomata, which is essential for gas exchange and transpiration in plants.

2. **Analyzing Statement 1**:
- "A decline in guard cell solute causes stomata to close."
- This statement is correct. When the osmotic concentration (solute concentration) in guard cells decreases, water exits the guard cells, leading to a loss of turgor pressure and causing the stomata to close.

3. **Analyzing Statement 2**:
- "Accumulation of large amounts of potassium in the guard cells is electrically balanced by the uptake of negatively charged ions, chloride and malate."
- This statement is also correct. The influx of potassium ions into guard cells is balanced by the uptake of negatively charged ions like chloride and malate, which helps maintain electrical neutrality.

4. **Analyzing Statement 3**:
- "High amounts of malate in the guard cells of open stomata accumulate by the hydrolysis of glycogen."
- This statement is incorrect. Malate accumulation in guard cells occurs due to the hydrolysis of glucose, not glycogen. Glycogen is not the primary source for malate production in this context.

5. **Analyzing Statement 4**:
- "The opening and closing of the stomata is controlled by the osmotic movement of water in or out of the guard cells."
- This statement is correct. The movement of water into and out of guard cells, driven by osmotic changes, determines whether the stomata open or close.

### Conclusion:
The incorrect statement about stomatal opening is **Statement 3**: "High amounts of malate in the guard cells of open stomata accumulate by the hydrolysis of glycogen."

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