EFFECT OF RED-LIGHT ON METABOLISM OF PHOSPHOINOSITIDES IN PLANT-CELL MEMBRANES

We studied the effect of red light (667 nm) on synthesis of phosphatid ylinositol diphosphate in membranes of etiolated oat protoplasts (Aven a sativa L.). The method of thin-layer chromatography on silica gel em ploying radioactive phosphorus revealed that red light addressed to ph ytochrome strengthens synthesis of the lipid. Successive exposure of p rotoplasts to red and far red light brings about the same effect. Far red light (730 nm), on the other hand, partially suppresses synthesis of phosphatidylinositol diphosphate. It is hypothesized that phytochro me affects synthesis of phosphoinositides and through them controls ca lcium ion homeostasis in the cell cytoplasm, which can be of significa nce for transduction of phytochrome effects.