Which of the following theory gives the latest explanation for the closure of stomata

Options

A. ABA theory
B. Munch theory
C. Starch-glucose theory
D. Active `K^(+)` transport theory

Answer

D

Explanation

Active `K^(+)` transport theory proposed by Levitt is the latest and most accepted theory for opening and closing of a stomata. According to this theory, pH of guard cells increase due to active `H^(+)` uptake by cell and `CO_(2)` assimilation by guard cell.
Rise is pH of guard cell causes hydrolysis of strach to form phosphoenol pyruvate. Phosphoenol pyruvate combine with `CO_(2)` with the help of PEPase and forms oxalic acid, which gets changed into malic acid.
`H^(+)` ions pass out of the guard cells, while `K^(+)` ions of epidermal cells pass into the guard cells `K^(+)` combine with malate. It results in absorption of water from adjacent cells, development of turgor and hence, opening of stomata.