Flavanoids in Pollen and Stigma of Brassica oleracea and Their Effects on Pollen Germination In Vitro

Brassica oleracea pollen was applied to a basic medium of 1.5per cent agar and 15 per cent sucrose to which flavanoids wereadded at three concentrations. Two types of agar were used;with agar 1, quercetin at a concentration of 0.5 x 10^–3per cent gave an increase in percentage germinating grains.With agar 2, an increase in germination occurred with kaempferoland naringin at concentrations of 0.5 x 10^–3 and 0.5 x10^–1 per cent respectively. Increase in pollen tube lengthoccurred with agar 2 and quercetin at a concentration of 0.5x 10^–3 per cent. The stigma tissue of B. oleracea contains at least three andthe pollen at least one glycoside of quercetin. The sugars inthe glycosides were not identified. Pollen germination and pollentube extension were not stimulated exclusively by the flavanoidspresent in the stigma. The flavanoid composition of the stigmadid not vary amongst five different S-allele genotypes, indicatingthat flavanoids are probably not directly involved in the incompatibilityreaction of B. oleracea.