EFFECTS OF SUPPLEMENTAL UV-B RADIATION ON PHOTOSYNTHETIC PIGMENT, PROTEIN AND GLUTATHIONE CONTENTS IN GREEN-ALGAE

Growth chamber experiments were conducted to investigate the effects of supplemental u.v.-B radiation (280-320 nm) on chlorophyll, carotenoid, protein and glutathione contents in two green algae, Chlorococcum infusionum (Schrank) Meneghini (Chlorococcales) and Chlorogonium elongatum (Dang.) France (Volvocales). U.v.-B exposure reduced chlorophyll, carotenoid and protein contents. The reduction in chlorophyll a content was higher than that of chlorophyll b. There were significant increases in cellular concentrations of total, reduced (GSH) and oxidized (GSSG) glutathione following u.v.-B treatment. However, the GSH/GSSG ratio was lower in u.v.-B exposed algae. Chlorogonium was found to be more responsive to supplemental u.v.-B exposure as compared to Chlorococcum. Variations in oxidized and reduced glutathione fractions due to supplemental levels of u.v.-B correlated with the response pattern of the algae.