Cell separation processes in plants - Models, mechanisms and manipulation

Abscission and dehiscence are developmental processes that involve the co-o rdinated breakdown of the cell wall matrix at discrete sites and at specifi c stages during the life cycle of a plant. In this review we examine the ev ents that influence the differentiation of abscission and dehiscence zone c ells and the changes that are associated with wall degradation. There is co nvincing evidence to believe that ethylene and auxin co-ordinate the timing of leaf, flower and fruit abscission but the events that regulate dehiscen ce and seed abscission are unclear. The use of transgenic plants and model systems such as Arabidopsis is assisting our understanding of the mechanism s that regulate abscission and dehiscence and the application of this infor mation will advance our understanding of cell separation processes in gener al. Armed with this knowledge it should be possible to either delay or acce lerate abscission and dehiscence, and this could have major benefits for th e agricultural and horticultural industries. (C) 2000 Annals of Botany Comp any.