SO_2胁迫对拟南芥抗氧化酶活性的影响

Effect of SO_2 on antioxidant enzyme activities in Arabidopsis thaliana

SO2是一种常见的全球性大气污染物,对人类健康和生态系统有严重的危害。多数植物在SO2胁迫时不能正常生长发育,因此研究SO2对植物的影响、分析植物逆境生理过程,对损伤和抗逆机理研究具有重要意义。文章以3周龄的拟南芥(Arabidopsis thalianal L.)植株为实验材料,对幼苗进行SO2(2.5、10、30mg·m-3)连续熏气,定时(8、56、104、152h)检测地上部分抗氧化酶活性和可溶性蛋白质含量的变化。结果表明,SO2熏气前期超氧化物歧化酶(SOD)和过氧化物酶(POD)活性诱导性增高,其中SOD活性增加最快,8h后即显著高于对照,并具有浓度效应,POD活性在SO2暴露8h后略有增高,56h、104h时明显增加;熏气152h后,SOD和POD活性显著降低。处理组和对照组的过氧化氢酶(CAT)活性和可溶性蛋白质含量在熏气前期略有增高,152h后有所降低。研究结果表明,环境中较高浓度的SO2对植物细胞具有氧化胁迫作用,并可能产生氧化损伤效应。

Sulfur dioxide （SO2） is one of the most common air pollutants, and causes harmful effects on human health and ecosystem balance at high concentration. Most plants can not grow normally under SO2 stress, some plants even died. It is important to study the mechanism for resistance to SO2 damage in A. thaliana. The results of present study showed that exposure to SO2 caused changes in antioxidant enzyme activities and soluble protein content in 3-week-old A. thaliana seedlings. Superoxide dismutase （SOD） activ- ity increased markedly during fumigation with 2.5 to 30 mg·m^-3 SO2, but decreased after 152 h exposure. Change of peroxidase （POD） activity showed a similar tendency to the result of SOD activity. POD activity increased appreciably after 8 h exposure, and showed significantly increase after seedlings exposure to 2.5-30 mg·m^-3 SO2 for 56 h to 104 h. There was no significant difference in shoot catalase （CAT） activity and soluble protein content between treatment groups and the control, with a little increment during earlier exposure and a decline after 152 h SO2 fumigation. Our results indicated that SO2 can cause oxidative stress and also oxidative damage to plant cells at higher concentrations.