Response Of Activitiy Of Antioxidant Enzymes To UV-B Radiation Enhancement In Ulva Pertusa Kjellman And Sargassum Thunbergii(Mert.) O.Kuntze.

Enhanced UV-B(280nm～320nm) radiation resulting from ozone depletion is one of global environmental problems .Not only marine organisms but also marine ecosystem can be affected by enhanced UV-B radiation.The effects of UV-B radiation on macro-algae were studied using Ulva pertusa Kjellman and Sargassum thunbergii(Mert .) O. Kuntze as the materials in this thesis .The result showed as follows:⒈Effects of UV-B radiation on the growth of Ulva pertusa Kjellman and Sargassum thunbergii(Mert .) O. KuntzeUV-B radiation could inhibit the growth of Ulva pertusa Kjellman and Sargassum thunbergii(Mert .) O. Kuntze, and the growth inhibition of Ulva pertusa Kjellman and Sargassum thunbergii(Mert .) O. Kuntze were more significant with the increasing dose of UV-B radiation treatment.⒉Effects of UV-B radiation on the active oxygen content and membrane Lipid Peroxidation of Ulva pertusa Kjellman and Sargassum thunbergii(Mert .) O. KuntzeUV-B radiation enhancement resulted in increment of active oxygen content in algal cells, H2O2 content,MDA content and the production rate of O2- showed increasing trend under UV-B radiation and deesterification damage mediated by active oxygens in Ulva pertusa Kjellman and Sargassum thunbergii(Mert .) O. Kuntze were appeared.⒊Effects of UV-B radiation on activity of antioxidant system of Ulva pertusa Kjellman and Sargassum thunbergii(Mert .) O. KuntzeActivity of antioxidant system in macro-algae could be affected under UV-B radiation . Ulva pertusa Kjellman ,the SOD activity,POD activity increased under low UV-B radiation treatment ,while showed decreasing trend under high UV-B radiation treatment. The CAT activity,APX activity,ASA content and GSH content showed decreasing trend with the increasing dose of UV-B radiation treatment. GR activity,GPX activity had no significant changes with the increasing dose of UV-B radiation treatment; Sargassum thunbergii(Mert .) O. Kuntze, the SOD activity, POD activity ,CAT activity showed decreasing trend with the increasing dose of UV-B radiation treatment. While GR activity,ASA content,GSH content showed increasing trend then decreased with the increasing dose of UV-B radiation treatment, GPX activity, APX activity had no significant changes with the increasing dose of UV-B radiation treatment.