Ozone-Enhanced Leaching of Onion Leaves in Relation to Lesion Production byBotrytis cinerea

Abstract

Analysis of dew from leaves of onion plants exposed or not exposed to 0.18 ppm (353 .mu.g/m3) ozone (O3) for 4 h indicated a substantial increase in leachate from O3-injured cells. The electrical conductivity and carbohydrate concentration were greater in dew from exposed plants than in dew from unexposed plants. Conidia of B. cinerea suspended in dew from the oldest nonsenscing leaf (leaf 1) or O3-exposed plants induced significantly more lesions per square centimeter of leaf surface when used to inoculate leaf 1 of unexposed plants than did conidia suspended in dew from leaf 1 of unexposed plants.