Cell separation processes in plants - Models, mechanisms and manipulation

Abscission and dehiscence are developmental processes that involve the co-ordinated breakdown of the cell wall matrix at discrete sites and at specific stages during the life cycle of a plant. In this review we examine the events that influence the differentiation of abscission and dehiscence zone cells and the changes that are associated with wall degradation. There is convincing evidence to believe that ethylene and auxin co-ordinate the timing of leaf, flower and fruit abscission but the events that regulate dehiscence and seed abscission are unclear. The use of transgenic plants and model systems such as Arabidopsis is assisting our understanding of the mechanisms that regulate abscission and dehiscence and the application of this information will advance our understanding of cell separation processes in general. Armed with this knowledge it should be possible to either delay or accelerate abscission and dehiscence, and this could have major benefits for the agricultural and horticultural industries. (C) 2000 Annals of Botany Company.