Question

What is potassium K+ ion theory of stomata. Explain

Answer 1

K ions are balanced by malate ions present in guard cells and also by taking in some Cl ions. This ion exchange occurs by the expenditure of ATP energy. Increased concentration of K and malate ions in the guard cells vacuole, will cause sufácient osmotic pressure to absorb water from surrounding cells.

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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.