中文摘要：

以钝顶螺旋藻（Spirulina platensis）为实验对象,用H2O2构建氧化损伤模型,研究不同浓度硒对H2O2胁迫钝顶螺旋藻的生长、干重、水溶性蛋白、光合色素、抗氧化酶（SOD、POD、APX、CAT和GSH-PX）及丙二醛（MDA）含量的影响,探讨硒作为过氧化保护剂的可能性及其机制。结果显示：（1）在0.25-2.5 mmol/L H2O2胁迫下,钝顶螺旋藻的藻密度、干重均显著降低,藻丝出现明显的断裂、破碎,藻体中MDA含量呈剂量性增加。（2）预添加一定浓度（2-1 000μmol/L）的Na2SeO3可显著抑制1 mmol/L H2O2胁迫下的钝顶螺旋藻藻密度和干重的降低趋势,改善藻丝的断裂受损,诱导藻体中SOD、POD、APX、CAT和GSH-PX抗氧化酶系活性的提高,同时显著增加水溶性蛋白的含量,缓解脂溶性色素的降解,降低MDA的积累和羟自由基的相对含量,拮抗H2O2诱导的氧化损伤。研究表明,硒的预处理可以有效提高钝顶螺旋藻的抗氧化能力,对氧化胁迫引起的生理伤害起到明显的缓解作用,以达到较理想的保护效果。

英文摘要：

To investigate the possibility and the underlying mechanisms of selenium（Se） as a protective agent for plants against oxidative stress,we examined the effects of various concentrations of Se on the growth,dry weight,contents of water-soluble proteins,photosynthetic pigments,antioxidant enzymes（SOD,POD,APX,CAT and GSH-PX）,and malondialdehyde（MDA） on Spirulina platensis under H2O2 stress in this study.The results showed that：（1）treatments with 0.25～2.5 mmol/L of H2O2 induced decrease in growth and biomass concentrations of S.platensis.Moreover,the algal filament was found to be fragmented and the level of MDA increased significantly after exposure to H2O2.（2）Pretreatments of S.platensis with 2~1 000 μmol/L of Na2SeO3 significantly inhibited the H2O2-induced decrease in growth and biomass concentrations,degradation of photosynthetic pigments,fragmentation of the algal filament and increase in intracellular levels of MDA and hydroxyl free radicals.In contrast,the activities of antioxidant enzymes,including SOD,POD,APX,CAT and GSH-PX,and the contents of water-soluble proteins were significantly elevated by Na2SeO3.Taken together,these results suggest that pretreatments with Se could improve the anti-oxidative ability of S.platensis,thus effectively protect plants against oxidative stress.