Q. Which ion helps in opening and closing of stomata?
A) $Mn^{+}$
B) $M{g^{2}}^{+}$
C) $C{a^{2}}^{+}$
D) $K^{+}$
Explanation
According to active $K^{+}$ theory of Levitt, opening of stomata occurs due to influx of $K^{+}$into guard cells. The source of $K^{+}$ions are nearby subsidiary and epidermal cells. The stomatal closure is considered to be brought about by exertion of $K^{+}and\ Cl^{-}$from the guard cells to epidermal tissue.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.