How does stomatal conductance increase in an elevated carbon dioxide environment?

Increase Co2 result in the more production of sucrose in the guard cells.That increases its osmotic potential.Water from adjoining cells rush in.Resulting increase in it's opening.

In most cases stomatal conductance decreases in elevated carbon dioxide environments. Why? Because the plants are getting more than enough carbon dioxide...more than they can convert into sugars. I know of only one plant where stomatal conductance increases in high carbon dioxide and it is a very preliminary finding.