Question

How does osmotic pressue effect osmosis with refrence to the opening and closing of stomata ?

Answer 1

Osmosis is required to occur in the guard cells in order to make them turgid and that ultimately leads to opening of stomata.
Osmotic pressure is numerically defined as that magnitude of the pressure required to be applied to stop water from diffusing in through semi permeable membrane. It is the pressure that tends to make everything even on both sides. It is responsible for movement of water molecules through osmosis. It depends on the solute concentration. Thus, more the solute concentration, more will be the osmotic pressure and then more will be the chances of osmosis. Osmotic pressure decreases with the movement of water in a cell. Decrease in osmotic pressure after movement of water in a guard cell is accompanied by increase in turgor pressure in a guard cell, which ultimately causes stomatal opening.