Light-Stimulated Inositol Phospholipid Turnover in Samanea saman Pulvini : Increased Levels of Diacylglycerol

Leaflet movement in Samanea saman is driven by an endogenous circadian clock and by light. We are investigating whether the effects of light on leaflet movement are mediated by increased inositol phospholipid turnover. We demonstrated previously that irradiation of excised pulvini with 15 to 30 seconds of white light decreases the levels of phosphatidylinositol monophosphate and phosphatidylinositol bisphosphate and increases the levels of inositol phosphates. We now report that the diacylglycerol level increases after 30 seconds of white light but returns to below the control level after 10 minutes of white light.