Question

The theory proposed to explain the mechanism of stomatal movement?

(a) The starch-sugar interconversion theory

(b) Theory of photosynthesis in guard cell

(c) Theory of glycolate metabolism

(d) Active potassium transport ion concept

I had been asked this question in a job interview.

Question is taken from Transportation in Plants topic in chapter Transport in Plants of Biology – Class 11

Answer 1

The correct answer is (a) The starch-sugar interconversion theory

To explain I would say: Steward in 1964 proposed a modified scheme of inter-conversion of starch and sugar for stomatal movement. Theory of photosynthesis in guard cells was given by Von Mohl in 1856 and proposed that chloroplasts in the guard cells photosynthesize leading to production of sugar. Theory of glycolate metabolism was given by Zelitch in 1963 and he proposed that production of glycolic acid in the guard cells is a necessary factor in stomatal opening. Active Potassium Pump theory was given by Fujino. Levitt & Rashke in 1975 supported the theory of the K+ ion transport active mechanism requires ATP.