Abstract: Guard cells surround stoma in the epidermis of plant leaves and stems. Stomatal guard cells have become a highly developed model system for characterizing early signal transduction mechanism in plants.Abscisic acid(ABA) can induce stomatal closure effectively through regulating the physiological and biochemical state of the guard cells. ABA regulated ion channels are key factors of ABA_induced stomatal closure. During the process,many factors are involved,including ROS,IP3, cADPR,protion phosphorylation and dephosphorylation etc.