Effect of Ethephon-Induced Ethylene on Abscission of Leaves and Fruits of Peaches1

Abstract Mature peach trees ( Prunus persica (L.) Batsch. cv. Southland) were treated with 0, 1.73, 2.42, and 3.11 Mmoles/1 of (2-chlorethyl)phosphonic acid (ethephon) and ethylene evolution was measured up to 9 days after treatment. Ethephon caused a marked increase in ethylene evolution, a sharp decrease in the breaking force of fruit abscission, and a pronounced increase in leaf abscission. Ethylene evolution was higher in leaves than fruits. In general, ethylene from tissue explants containing the abscission zone of fruits was higher than that of explants from the side of fruits from treated trees. However, it was postulated that ethylene has an overall affect on all tissue with subsequent abscission rather than a direct effect on the abscission zone of leaves and fruits of peaches.