Before opening of stomata accumulation of the following ion is seen in

Options

A. `PO_4`
B. `K^(+)`
C. `Mg++`
D. `Na^(+)`

Answer

### Step-by-Step Solution:

1. **Understanding Stomatal Function**: Stomata are small openings on the surfaces of leaves that allow for gas exchange. Their opening and closing are regulated by guard cells.

2. **Role of Ions in Stomatal Opening**: For stomata to open, certain ions must accumulate in the guard cells. This accumulation leads to a change in water potential.

3. **Key Ion for Stomatal Opening**: The primary ion involved in the opening of stomata is potassium (K⁺). When potassium ions accumulate in the guard cells, they lower the water potential inside these cells.

4. **Mechanism of Stomatal Opening**: As potassium ions enter the guard cells, water follows by osmosis. This influx of water causes the guard cells to become turgid (swollen), which in turn causes the stomatal pore to open.

5. **Conclusion**: Therefore, the accumulation of potassium ions is essential before the opening of stomata.

### Final Answer:
The correct answer is **Potassium ions (K⁺)**.

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