Question

The metal/non-metal ion involved in opening and closing of stomata is

• A. $F{e}^{+++}$
• B. $C{u}^{++}$
• C. $K^{+}$
• D. $N{a}^{++}$

Answer 1

Answer: (C)

The mechanism of opening and closing of stomata is explained by active $K^{+}$ion transport theory which was put forward by Levitt (1974). Given flowchart show the mechanism of stomatal opening : Guard cells maintain their electroneutrality by balancing $K\cdot$ with malate and $C{l}^{-}$, During night or dark: $C{O}_2$ cone, increases in sub-stomatal cavities $\to$ ABA participation $\to K^{+}$ions exchange stopped $\to K^{+}$ ions transported back into subsidiary cells $\to$ Decreased $pH\to$ Starch synthesized in guard cells $\to$ Decreased O.P. of guard cells $\to$ Exosmosis from guard cell $\to$ Stomata close.