Yuichiro Nishizaki

Effects of blue light on electrical potential and turgor in pulvinar motor cells ofPhaseolus

Pulvinar motor cells ofPhaseolus vulgaris L display transient depolarization of the membrane potential and a turgor pressure decrease when exposed to a pulse of blue light. To analyze the mechanism of the transient depolarization, the effects of some factors such as anoxia, metabolic inhibitors and specific inhibitors of H+-ATPase have been examined. The findings have led to the conclusion that blue light inactivates the electrogenic H+-pumping ATPase in the plasma membrane of the motor cells. This inactivation seems to suppress ion uptake and decrease the turgor pressure of the motor cells.