Ethylene-promoted tomato flower abscission and the possible involvement of an inhibitor.

The abscission zone in tomato (Lycopersicon esculentum (L.) Mill. flower pedicels is morphologically distinguishable prior to separation and is delineated by an indentation of the epidermis. Exposure of excised pedicels with the flower attached to ethylene results in abscission within 12 h and this can be accelerated by flower removal. Abscission of excised pedicels with the flower removed takes place in the absence of exogenous ethylene but this is delayed by pretreatment with aminoethoxyvinyl glycine, an inhibitor of ethylene biosynthesis. The data presented support the hypothesis that flower tissue is the source of an abscission inhibitor.