The effect of selenium on Porphyridium sp. UTEX 637 major antioxidant enzyme system, including glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT) activities, and malondialdehyde (MDA) content, were investigated. Porphyridium sp. Was cultured in artificial seawater ASW medium containing 0.5mg·L-1 selenium. GSH-Px, SOD, CAT activities, and MDA content were determined by kits, nitroblue tetrazolium (NBT) photoreduction, UV spectro-photometry, and thiobarbituric acid (TBA) analysis, respectively. The results show that selenium improved the antioxidation activity of Porphyridium sp. By increasing the activity of GSH-Px (p<0.05). The GSH-Px activity of Se-treated group and control group reached the highest on the 15th day, and the GSH-Px activity of Se-treated group was heightened to 4.31U, which was 1.31 fold higher than that of the control group. SOD and CAT activities reached the maximum on the 18th day and 15th day, respectively, but the differences between the experimental group and the control were not significant (p>0.05). The activity of SOD and CAT was not significant at the 0.5mg·L-1 concentration of selenium. The content of MDA in Se-treated group was 15.21% lower than that in the control group.%利用添加0.5mg.L-1硒的人工海水(ASW)培养基培养紫球藻Porphyridium sp.UTEX 637,并采用试剂盒、氯化硝基四氮唑蓝(NBT)光化学还原反应法、紫外分光光度法、硫代巴比妥酸(TBA)分析法测定谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)的活性及丙二醛(MDA)的含量,着重探讨硒对紫球藻抗氧化酶活性及丙二醛含量的影响.结果表明,硒明显促进紫球藻细胞的GSH-Px活性p＜0.05).加硒处理组和未加硒对照组紫球藻的GSH-Px活性均在第15天达到最高；加硒组紫球藻的最大酶活性达到4.31个酶活力单位(U),为对照组的1.31倍.SOD和CAT的活性分别在第18天和15天达到最大值,但加硒组与对照组之间差异不显著(p＞0.05),说明0.5mg.L-1硒对紫球藻的SOD和CAT活性影响不明显.加硒能明显降低藻细胞丙二醛的含量,加硒组藻细胞的丙二醛含量比对照组藻细胞的丙二醛含量降低了15.21％.
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