CYD, A MUTANT OF PEA THAT ALTERS EMBRYO MORPHOLOGY IS DEFECTIVE IN CYTOKINESIS

Embryogenesis in higher plants requires the precise regulation of cell division, orientation of cell elongation and specification of cell di fferentiation. The division plane is determined by the position of a n ew cell plate at cytokinesis. A mutant of pea has been isolated in whi ch both the embryo pattern and surface morphology is altered. The phen otype of the mutant is manifest primarily in the cotyledons where cell plates only partially form, generating cell wall stubs and multinucle ate cells. Some cotyledonary cells of the mutant proceed through nine DNA replication cycles, including nuclear division, but not cytokinesi s, producing nuclei with a DNA content of ca. 1000C. The cytological p henotype of the mutant could be mimicked by the treatment of wild-type cells with caffeine. We have termed this mutant cytokinesis-defective (cyd). (C) 1995 Wiley-Liss, Inc.