I understand how plants open stomata, with the H+ ion removal and the resulting K+ ion influx in the guard cells to induce turgor (wikipedia article here), though not how this process relates to presence/absence of light.
However, I don't understand how CAM plants manage to keep their stomata closed during the day and how it relates to CAM photosynthesis (if at all). I know that malate ions are involved in the opening of the stomata in C3 plants, could the malic acid production in CAM photosynthesis contribute to this?
So my question is: How do CAM plants induce closing of the stomata and what signal triggers this?