Abstract: To provide a theoretical basis for the breeding of salt-tolerant germplasm resources in Bothriochloa ischaemum， this experiment investigated the effects of ascorbic acid （AsA） priming on the AsA-GSH cycle in the embryonic mitochondria of B. ischaemum under salt stress. Seeds of ‘Taihang’ B. ischaemum were used as experimental materials， and were primed with 0.1 mmol·L^-1 AsA solution for 12 h， then were germinated in NaCl and Na₂SO₄ solutions containing 30 mmol·L^-1 Na⁺. The changes in AsA-GSH cycle enzymes activities and lipid peroxidation levels in their mitochondria of radicle and plumule were analyzed. The results showed that the activities of catalase （CAT）， glutathione transferase （GST）， dehydroascorbate reductase （DHAR） and monodehydroascorbate reductase （MDHAR） in the mitochondria of radicle and plumule of B. ischaemum were increased significantly after AsA priming （P<0.05）， while the activities of superoxide dismutase （SOD）， ascorbate peroxidase （APX） and glutathione peroxidases （GPX）， as well as the contents of malondialdehyde （MDA） and H₂O₂， were decreased significantly （P<0.05）. Under salt stress， APX and GPX were the key enzymes regulating salt tolerance of embryonic mitochondria in B. ischaemum， but CAT， MDHAR and DHAR were served as the core regulatory enzymes after AsA priming. The membership function analysis indicated that priming with 0.1 mmol·L^-1 AsA had the best effect on enhancing the activities of mitochondrial AsA-GSH cycle enzymes in the radicle of B. ischaemum under 30 mmol·L^-1 NaCl stress.

Key words: Bothriochloa ischaemum, Saline stress, Ascorbic acid priming, Mitochondria, AsA-GSH cycle

摘要： 试验探究了抗坏血酸（Ascorbic acid，AsA）引发对盐胁迫下白羊草（Bothriochloa ischaemum）种胚线粒体AsA-GSH循环的影响，以期为选育耐盐白羊草种质资源新材料提供理论依据。以‘太行’白羊草种子为材料，经0.1 mmol·L^-1的AsA溶液引发12 h后，采用Na⁺浓度为30 mmol·L^-1的NaCl和Na₂SO₄溶液进行胁迫萌发试验，分析其胚根和胚芽线粒体AsA-GSH循环酶活性及脂质过氧化水平的变化规律。结果表明，AsA引发后，白羊草胚根和胚芽线粒体中过氧化氢酶（Catalase，CAT），谷胱甘肽转移酶（Glutathione transferase，GST），脱氢抗坏血酸还原酶（Dehydroascorbate reductase，DHAR）和单脱氢抗坏血酸还原酶（Monodehydroascorbate reductase，MDHAR）活性显著上升（P<0.05），超氧化物歧化酶（Superoxide dismutase，SOD），抗坏血酸过氧化物酶（Ascorbate peroxidase，APX），谷胱甘肽过氧化物酶（Glutathione peroxidases，GPX）活性及丙二醛（Malondialdehyde，MDA）和H₂O₂含量显著下降（P<0.05）。盐胁迫下，APX和GPX是调控白羊草种胚线粒体耐盐的关键酶，而AsA引发后则以CAT，MDHAR和DHAR为关键酶。隶属函数分析结果表明，0.1 mmol·L^-1的AsA引发对30 mmol·L^-1 NaCl胁迫下白羊草胚根线粒体AsA-GSH循环酶活性的提升效果最好。

关键词: 白羊草, 盐胁迫, 抗坏血酸引发, 线粒体, AsA-GSH循环