Question

3. Explain the mechanism of opening and closing of stomata of sugar to starch theory

Answer 1

The opening and closing of the pore is a function of the guard cells. The guard cells swell when water flows into them, causing the stomatal pore to open. Simillarly the pore closes if the guard cells shrink

Answer 2

There are two theories about the opening and closing of stomata:

• Potassium ion concentration theory
• Sugar concentration theory

Potassium ion concentration theory:

This is the recent theory in which ATP is used to actively pump the potassium ions of the adjacent cells into the guard cells.

Sugar concentration theory:

This the old theory in which the guard cells become turgid and bulbs out words due to their thin outer wall, thus widening the stomatal opening lying in between.