Cell Cycle Regulation in Plants

Plant Biology Laboratory’, The Salk lnstitute for Biological Studies, 10100 North Torrey Pines Road, La Jolla, California 92037 Cell division plays a crucial role during a11 phases of plant development. Continuing organogenesis and plastic growth responses to a changing environment require precise spatial, temporal, and developmental regulation of cell division activ- ity in meristems. The molecular analysis of cell division and its regulation in plants lags far behind such studies in yeast and animals. Since the cell theory was proposed by Schleiden and Schwann in 1838, many approaches have been taken to elucidate how cells divide, but insight into the molecular basis of division control developed only after the genetic analysis of cell division was initiated in yeast 25 years ago (Hartwell et al., 1970). Cell division cycle mutants in the yeasts