The Mechanism of Stomatal Closure (IMAGE) Institute for Basic Science Caption Stomatal closure involves the plant hormone abscisic acid, intracellular calcium and reactive oxygen species (ROS). IBS scientists discovered how L-methionine-activated calcium channels GLR3.1/3.5 (green) contribute to this mechanism. Credit IBS Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.