Ethylene and abscission

A substantial body of literature supports the involvement of ethylene in abscission of leaves, flowers and flower parts, and fruit. Exogenous ethylene accelerates abscission in many, but not all, abscising plant systems. In some cases, endogenous ethylene production increases before abscission, while in others a change in ethylene sensitivity can be demonstrated. Ethylene interacts with auxin in regulating abscission, particularly in leaves and fruit. Ethylene has been shown to regulate expression of genes involved in cell separation, including cellulases and pectinases. Such regulation has been demonstrated at the level of mRNA abundance, but post-transcriptional regulation may also be important.