Q. Which of the following elements is responsible for maintaining turgor in cells :
(a) Magnesium
(b) Sodium
(c) Potassium
(d) Calcium
Solution :
Correct option : C Potassium is required for the maintenance of the turgidity of guard cells. In the guard cells, starch is converted into malic acid in the presence of light (during daytime). Protons formed are used by the guard cells for the uptake of K+ ions. In this way, the concentration of K+ ions increases in guard cells. The potassium combines with malate to form potassium malate. This increases the solute concentration of the guard cells. The guard cell withdraws water from the nearby cells and becomes turgid. So, the correct answer is option C.