EFFECT OF SUGAR CONCENTRATION ON POLLINIUM GERMINATION IN SOME MEMBERS OF ASCLEPIADACEAE

Effect of sugar concentration on in-vitro pollinium germination in 8 m embers of Asclepiadaceae viz., Calotropis procera sap. hamiltonii, Car alluma edulis, Caralluma tuberculata, Ceropegia bulbosa, Glossonema va rians, Leptadenia pyrotechnica, Pentatropis nivalis and Pergularia dae mia was studied. Although pollinia of each taxa germinated in a wide r ange of sucrose concentration (i.e. 5-40%) but each taxa showed a spec ific sucrose concentration al which optimal pollinium germination occu rred. In P. nivalis and Per. daemia, coiling and beading of pollen tub es occurred at 20-40% sucrose concentrations while in other taxa at 5- 15% concentrations. Optimal sucrose concentration required for in-vitr o pollinium germination was similar ro the average sugar concentration observed in the floral nectar of the studied taxa except in P. nivali s where maximum pollinium germination occurred at 10% sugar concentrat ion as compared to 24% sugar concentration in its floral nectar.