Question

Malate or K${}^{+}$ hydrolysis theory was given for

• A. Starch metabolism.
• B. Stomatal movement.
• C. Ascent of sap.
• D. All of the above.

Answer 1

Answer: (B)

Stomatal movement.

There are three more theories for mechanism of stomatal movement
(A) Hydrolysis of guard cell photosynthesis
(B) Classical starch hydrolysis theory
(C) Malate or $k^{+}$ ion pump hydrolysis.

Malate or $k^{+}$ ion pump hypothesis theory was put forward by Levitt $\left(1974\right)$. It is considered as the modern one. It states that the change in the turgor pressure of the guard cells regulates the opening and closing of stomata.