Question

Which ion is accumulated in the guard cells before opening of stomata?

• A. $P{O}_4$
• B. $K^{+}$
• C. $M{g}^{++}$
• D. $N{a}^{+}$

Answer 1

The correct option is B $K^{+}$

According to the most widely accepted theory of stomatal opening and closing, potassium ions are involved in turgor movement of guard cells. Inflow of potassium ions decreases water potential in guard cells, which leads to inflow of water. Consequently guard cells swell and stomatal pore opens. When potassium ions move out, these events are reversed and stomatal pore closes.