Guard cells

[TheVirus]

I understand that guard cells are the only epydermal cells in the leaf which have chloroplasts. I thought it had to do with making sugar for increasing the water potential and help open the stomata, but i read that there is no evidence suggesting photosynthesis takes place there, and that it is the potassium concentration that takes care of regulating water in the guard cells. So, does anybody know or have a theory as to what is the function of chloroplasts in the guard cells?

[JackBean]

It seems it is due to the photosynthesis
http://answers.yahoo.com/question/index ... 241AAHjbsz

http://onlinelibrary.wiley.com/doi/10.1 ... doc.x/full

[JackBean]

and BTW it's epIdermis

[leftventricle]

Speaking of guard cells...I had some questions.

The water that moves in or out of the guard cells when opening or closing has nothing to do with transpiration, am I correct?

Transpiration has to do with the loss of water through the STOMATA of a leaf?

[leftventricle]

And also, why does decreased levels of sucrose cause the stomata to close at night?

[JackBean]

and guard cells guard stomata, don't they?