Opening And Closing of the Stomata

At first I did not fully understand the opening and closing factors of the stomata. We understand that the stoma are pores on the epidermal layer of leaves, where gas exchange occurs. This gas exchange is where the plant takes in carbon dioxide and releases water and oxygen. We must now understand how these pores open and close and the contributing factors. The kidney shaped guard cells are the cells that physically open and close the stomata. When Potassium ions (K+) diffuse into the guard cells from the surrounding cells, this sends a signal to open the stomata. This is due to the concentration gradient that is formed by the K+ when there are less free water molecules inside the guard cells. (We know water flows from areas of high concentration to low). The opposite happens in order to close the stomata. This time the K+ diffuse out of the guard cells, again forming a concentration gradient in the opposite direction. What was stomata with me? :D This concept is easy now!!