XVI International Botanical Congess

In plant development, asymmetric cell division is essential for differentiation in many cases. Fern gametophytes are good materials for analysis of asymmetric division because of simple organization of tissues. Ceratopteris richardii is suitable for mutant isolation because of rapid life cycle, but experimental system to analyses asymmetric division was not reported. I report nuclear migration and asymmetric division in light-induced rhiziod formation of Ceratopteris richardii. A dark-grown strap-shaped prothallus has an apical meristem, a subapical elongation zone and a basal zone where no growth occurs (Murata et al. 1997). When prothalli were transferred from dark to white light, the nucleus in subapical cells migrated from a center to a basal side of a cell and then cell division occurred to produce a rhizoid. Brief irradiation of red light was effective for induction of cell division. Role of actin and microtubles for asymmetric division is discussed.