Question

Active $K^{+}$ ion exchange mechanism of opening and closing of stomata was given by

• A. Khorana
• B. Scarth
• C. Levitt
• D. Kohli

Answer 1

The correct option is C Levitt

Potassium is an important macronutrient for plants. Potassium ions cause turgor movement of guard cells.

Gain of potassium ions by guard cells causes a decrease in water potential of guard cells which leads to inflow of water into the guard cells. This makes guard cells turgid and they swell. Increase in turgidity of guard cells opens the stomatal pore.

Movement of potassium ions out from guard cells results in an increase in water potential, they lose water due to exosmosis, become flaccid and stomatal pore closes.

This mechanism of stomatal opening and closing was first stated by Levitt.