Carbon dioxide enrichment, transpiration and 1-aminocyclopropane-1-carboxylic acid-dependent ethylene release from oat leaves

Abstract

Enrichment of air with carbon dioxide up to 1200 μl ṡ 1⁻¹ air results in lower transpiration rates from oat (Avena sativa) seedling leaves held in the light at 30% relative humidity. Carbon dioxide treatment also enhances the release of ethylene from leaves treated with 1-aminocyclopropane-1-carboxylic acid (ACC). Thus, while the uptake of ACC via the transpiration stream is depressed by 33% by carbon dioxide enrichment, the release of ethylene from a given amount of ACC is increased by 400%. Neither ethylene nor ACC appear to affect the transpiration rate. The enhancement of ACC-dependent ethylene release cannot be simply correlated with stomatal behaviour.