How do changes in K+ ion conc in the guard cells cause change in the guardcell turgidity?

Question

and thus control the size of the stomatal pore?

Answer 1

K+ concentration in a guard cell significantly affects guard cell turgidity.
When there isn't any (or much) K+ in guard cells, there is more water, so the cells remain flaccid (loose) (at equilibrium, or osmohappiness) and stay closed.
When there is a significant amount of K+ in guard cells, they take in more water, causing them to become turgid and opening up to allow for the exchange carbon dioxide and oxygen with the environment through photosynthesis.
Hope this helps!

Answer 2

How Stomata Operate:

Turgid guard cells open the stomata, while flaccid ones close them.
The potassium (K+) ion is responsible for the stomatal action.
Uptake of K+ causes the cell to become turgid decreasing its water potential.
The stomata open at dawn caused by the light inducing the cells to take in K+. An internal clock (circadian rhythm) will make them open even if in they are kept in the dark.
Guard cells will close due to water deficiency and high temperatures.

Answer 3

When there are large amounts of K+ in the intracellular fluid, water moves from the extracellular fluid into the cell via osmosis.

Answer 4

im guessing that its something to do with antiport of water