Abstract
In most higher plants, the shoot shows negative gravitropism. We have isolated many abnormal shoot gravitropism mutants (sgr) in Arabidopsis to analyze the molecular mechanisms. It has been strongly suggested that endodermal cells percept gravity orientation. They contain amyloplasts, most of which locate at the base of the cell. Several lines of evidence suggest that the interaction between the amyloplasts and the vacuolar membrane in endodermal cells is very important in the gravitropism. To analyze the series of events before and after gravistimuli, we constructed Vertical Microscope System. In this symposium, we will report in vivo and time-lapse imaging of the amyloplast movements and vacuolar membrane dynamics in the endodermal cells of both wild-type and sgr mutants inflorescnece stems.
