Cell Separation Processes in Plants--Models, Mechanisms and Manipulation

Abscission and dehiscence are developmental processes that involvethe co-ordinated breakdown of the cell wall matrix at discretesites and at specific stages during the life cycle of a plant.In this review we examine the events that influence the differentiationof abscission and dehiscence zone cells and the changes thatare associated with wall degradation. There is convincing evidenceto believe that ethylene and auxin co-ordinate the timing ofleaf, flower and fruit abscission but the events that regulatedehiscence and seed abscission are unclear. The use of transgenicplants and model systems such as Arabidopsis is assisting ourunderstanding of the mechanisms that regulate abscission anddehiscence and the application of this information will advanceour understanding of cell separation processes in general. Armedwith this knowledge it should be possible to either delay oraccelerate abscission and dehiscence, and this could have majorbenefits for the agricultural and horticultural industries.Copyright 2000 Annals of Botany Company Abscission, dehiscence, cell separation, wall degradation, gene expression, polygalacturonase, ß-1,4-glucanase, pathogenesis-related proteins, ethylene