【摘要】 为了了解在UV B辐射增强的胁迫下,南极冰藻ChlorophyceaeL 4细胞内保护酶系统对活性氧自由基的清除作用,对不同辐射强度下ChlorophyceaeL 4细胞中丙二醛含量的变化、自由基的产生速率和相应的保护酶系统的变化进行了测定。结果表明,在UV B辐射增强的初期(1～3d),ChlorophyceaeL 4中丙二醛含量的迅速提高,但随后很快降低,在低强度UV B(35μW·cm-2)辐照下保护酶活性能够恢复到基本水平。在UV B辐射增强的胁迫下,ChlorophyceaeL 4中的超氧化物歧化酶、过氧化物酶和过氧化氢酶的活性明显比对照组的高,而且在高强度(70μW·cm-2)的辐照下,酶活性更高。ChlorophyceaeL 4中的抗坏血酸过氧化物酶的活性在UV B辐射增强的胁迫下略有升高或变化不大。本研究结果表明,保护酶系统在南极冰藻适应南极强辐射环境中起着非常重要的作用。更多还原

【Abstract】 In order to understand the active oxygen free radical clearing function of protecting enzymes in antarctic ice mircoralgae Chlorophyceae L-4 at diferent UV-B radiation intensities, the malonaldehyde（MAD） content changes, the free radical generation rate and the corresponding protecting enzyme changes in Chlorophyceae L-4 at Different UV-B radiation intensities were determined. It is shown from the determined results that the MAD content in Chlorophyceae L-4 increased rapidly in early days （1 to 3 days） of UV-B radiation enhancement, then decreased rapidly, and the protecting enzyme activity could return to fundamental level at low UV-B radiation intensity (35μm·cm^-2). Under the stress of UV-B radiation enhancement, the superoxide dismutase（SOD）, peroxidase （POD） and catalase （CAT） activities in Chlorophyceae L-4 were obviously higher than those in the control, and their activities became higher at high UV-B radiation intensity (70μm·cm^-2). The ascorbic acid peroxidase （APX） activity in Chlorophyceae L-4 increased slightly or kept stable under the stress of UV-B radiation enhancement. The above experimental results indicate that the protecting enzyme system plays an important role in the adaptation of antarctic ice microalgae to the strong antarctic radiation environment.更多还原