Effect of repetitive ozone treatment on bean plants—stress ethylene production and leaf necrosis

Abstract

Bean plants were repetitively treated with varying ozone (O 3) concentrations and exposure times on successive days. Our studies clearly demonstrate that a series of successive short episodes of ozone exposure is more damaging to the plants than continuous exposure of the same O 3 concentration for the same total exposure time. In contrast to single ozone exposure experiments repetitive ozone treatment causes stress ethylene production and the beginning of leaf necrosis at the same time. The “no effect levels” estimated for O 3 with single exposure experiments can not be applied to repetitive ozone exposure episodes because the plants are more sensitive under these conditions.