Auxin Gradient Theory of Abscission Regulation

Abstract

The auxin gradient across an abscission zone is the principal regulator of abscission which occurs after a fall in the ratio of distal to proximal auxin. Abscission is accelerated when exogenous auxin is increased in the proximal region over that in the distal region which is the reverse of the condition when there is no abscission. Applied auxin may not accelerate rather than retard abscission if it is translocated or inactivated as rapidly as it is absorbed.