How does stomatal pore open and close ?

Explanation

**Step-by-Step Solution:**

1. **Understanding Guard Cells**: The stomatal pore is surrounded by specialized cells called guard cells. These cells are typically kidney or bean-shaped and are made of cellulose fibrils.

2. **Role of Subsidiary Cells**: Adjacent to guard cells are subsidiary cells that play a crucial role in regulating the opening and closing of the stomata. These cells contain high concentrations of sodium and potassium ions.

3. **Increase in Solute Potential**: When the concentration of sodium and potassium ions increases in the guard cells, the solute potential (the potential of water to move) also increases. This change in solute concentration is critical for the movement of water.

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