EFFECTS OF EXTRACELLULAR CALMODULIN ON POLLEN GERMINATION AND TUBE GROWTH

The effects of calmodulin (CaM) antagonist W7-agarose, anti-CaM serum and exogenous Purified CaM on pollen germination and tube growth of Fo rsythia suspensa were studied. The pollen germination and tube growth were inhibited or completely stopped by CaM antagonist W7-agarose. The addition of exogenous purified CaM stimulated pollen germination and tube growth, whereas the same amount of bovine serum albumin (BSA) had no effect. The inhibitory effects caused by W7-agarose and anti-CaM s erum could be reversed completely by the addition of exogenous purifie d CaM. The tube growth of germinated pollen was also inhibited or comp letely stopped by W7-agarose. The results suggest that Endogenous extr acellular CaM initiates pollen germination and tube growth, whereas ex ogenous CaM enhances the above processes.