In higher plants, cytokinesis is usually accomplished by the formation
of a cell plate between daughter nuclei. This is a process of exocyto
sis in which Golgi-derived vesicles containing cell wall material fuse
to form a new primary cell wall bordered on either side by plasma mem
brane. The cell plate expands and its edges fuse with the edges of the
parent cell wall. Our understanding of this process has recently been
furthered by the detailed analysis of cell plate formation in cryofix
ed tissues, and by the phenotypic description of plant mutants in whic
h cytokinesis is impaired. The positional cloning of one of these gene
s in Arabidopsis has identified a novel syntaxin which appears to be r
equired for cell plate formation.