Abstract: In order to explore the influence of exogenous H₂O₂ priming on the oxidation resistance of AsA-GSH cycles in embryonic cells of oat (Avena sativa) seeds,oat seeds were used as the experimental materials and primed with different concentrations of H₂O₂ (0,0.96,1.92,3.84 and 7.68 mol·L^-1) for 0,6,12 and 18 h. The changes in the level of lipid peroxidation and their antioxidant enzymes activities of ascorbic acid-glutathione (AsA-GSH) cycles were analyzed in their embryonic cells. The results showed that the concentration and priming time were closely related to the oxidation resistance of AsA-GSH cycles in embryonic cells of oat seeds,resulting in a significant (P<0.05)increase in the contents of H₂O₂ and malondialdehyde,which increased with the increase of concentration or priming time. However,the antioxidant capacity of AsA-GSH cycles in embryonic cells of oat seeds enhanced at low H₂O₂ concentration (0.96 mol·L^-1) or short priming time (6 h),and weakened at high H₂O₂ concentration (3.84~7.68 mol·L^-1) or long priming time (12~18 h). Ascorbate peroxidase,monodehydroasorbate reductase and dehydroascorbate reductase were the pivotal enzymes to maintain the H₂O₂ equilibrium in the embryonic cells of oat seeds under priming with exogenous H₂O₂.

Key words: Hydrogen peroxide, Oat, Seed priming, Embryo, Ascorbic acid-glutathione cycles

摘要： 为了探究外源H₂O₂引发对燕麦(Avena sativa)种胚细胞AsA-GSH循环抗氧化性能的影响，本试验以燕麦种子为研究对象，用不同浓度(0，0.96，1.92，3.84和7.68 mol·L^-1)的H₂O₂引发燕麦种子0(CK)，6，12和18 h，分析其种胚细胞抗坏血酸-谷胱甘肽(Ascorbic acid-glutathione，AsA-GSH)循环抗氧化酶活性、脂质过氧化水平的变化规律，结果表明：外源H₂O₂引发浓度和时间对燕麦种胚细胞的抗氧化能力有密切影响，导致其H₂O₂和丙二醛含量显著增加(P<0.05)，且浓度越高或引发时间越长则增加越多，而其AsA-GSH循环的抗氧化能力在低浓度(0.96 mol·L^-1)或短时间(6 h)引发时被提高，而在高浓度(3.84~7.68 mol·L^-1)或长时间(12~18 h)则会被减弱。抗坏血酸过氧化物酶、单脱氢抗坏血酸还原酶和脱氢抗坏血酸还原酶是外源H₂O₂引发燕麦种胚细胞内维持H₂O₂平衡所依赖的关键酶。

关键词: 过氧化氢, 燕麦, 种子引发, 种胚, 抗坏血酸-谷胱甘肽循环