(ab sighs´ ik) [L. abscissio: breaking off] • A plant growth substance having growth-inhibiting action. Causes stomata to close.
Abscission Abscission is the orderly process by which a leaf dies and falls off the tree or a fruit ripens and falls from a plant.
A phytohormone implicated in the control of many plant responses to abiotic stress, such as extent of stomatal opening under water deficit (i.e. drought) conditions.