Abstract: In order to explore the effects of salt stress on mitochondrial antioxidant resistance of Bothriochloa ischaemum seedlings and provide a theoretical basis for breeding new salt-tolerant varieties of Bothriochloa ischaemum,the seeds of Bothriochloa ischaemum were used as materials to conduct germination experiment under different concentration of Na⁺ (0(CK),10,30,90 mmol·L^-1). The changes of mitochondrial antioxidant enzyme activities and lipid peroxidation contents in seedlings were analyzed. The results showed that the activities of superoxide dismutase (SOD),catalase (CAT) and glutathione peroxidase (GPX) in mitochondria of radicle and plumule were higher under the Na⁺ treatments than CK,but as the concentration of Na⁺ increased,the the activities of glutathione S-transferase and glutathione reductase gradually decreased,the ascorbate peroxidase (APX) activity of mitochondria in radicle decreased significantly (P<0.05),the APX activity of mitochondria in plumule increased firstly and then decreased,and their contents of H₂O₂ and malondialdehyde increased gradually. Salt stress had different effects on the antioxidant resistance of mitochondria in different parts of Bothriochloa ischaemum seedlings,and the mitochondria in radicle was more sensitive than that in plumule. SOD,CAT and GPX were the key enzymes to maintain the ROS homeostasis of mitochondria in Bothriochloa ischaemum seedlings under salt stress.

Key words: Bothriochloa ischaemum, Salt stress, Seedling, Mitochondria, Antioxidant resistance

摘要： 为探讨盐胁迫对白羊草(Bothriochloa ischaemum)幼苗线粒体抗氧化性能的影响，以期为培育耐盐白羊草新品种提供理论依据。试验以白羊草种子为材料，在Na⁺浓度为0(CK)，10，30，90 mmol·L^-1的盐胁迫下进行萌发试验，分析其幼苗线粒体抗氧化酶活性及脂质过氧化含量的变化规律。结果表明：随着Na⁺浓度的增加，白羊草幼苗胚根和胚芽线粒体超氧化物歧化酶(Superoxide dismutase，SOD)，过氧化氢酶(Catalase，CAT)，谷胱甘肽过氧化物酶(Glutathione peroxidase，GPX)活性均高于CK，谷胱甘肽巯基转移酶，谷胱甘肽还原酶活性逐渐降低，胚根线粒体抗坏血酸过氧化物酶(Ascorbate peroxidase，APX)活性显著降低(P<0.05)，而胚芽线粒体APX活性先升高后降低，H₂O₂和丙二醛含量逐渐升高。盐胁迫对白羊草幼苗不同部位线粒体抗氧化性能的影响存在差异，胚根线粒体比胚芽更敏感，SOD，CAT，GPX是维持盐胁迫下白羊草幼苗线粒体ROS动态平衡的关键酶。

关键词: 白羊草, 盐胁迫, 幼苗, 线粒体, 抗氧化性能