Abscisic acid is called stress hormone as it induces various responses in plants against stress conditions. It increases the tolerance of plants towards various stresses. It induces the closure of stomata during water stress. It promotes seed dormancy and ensures seed germination during favourable conditions. It helps seeds withstand desiccation. It also helps in inducing dormancy in plants at the end of the growing season and promotes abscission of leaves, fruits and flowers.