Question

How phosphorylase enzyme open the stomata in starch sugar interconversion theory?

Answer 1

1. The discovery of enzyme phosphorylase in guard cells by Hanes (1940) greatly supports the starch-sugar interconversion theory.
2. The enzyme phosphorylase hydrolyses starch into sugar and high PH followed and the opening takes place during the night.

• Day:

1. \[\ce{Starch ->[phosphorylase] sugar}\]
2. Photosynthesis occur
3. pH – increased
4. Movement of water from
5. subsidiary cells to guard cells
6. Guard cells become turgid
7. Opening of stomata

• Night:

1. \[\ce{Sugar ->[phosphorylase] starch}\]
2. No Photosynthesis
3. pH – lowered
4. Movement of water from guard cells
5. Guard cells become flaccid
6. Closure of stomata