外源过氧化氢对水曲柳体胚发生中外植体抗氧化生理特性的影响

Effects of Exogenous Hydrogen Peroxide on Antioxidant Physiological Characteristics of Explants during Somatic Embryogenesis of Fraxinus mandshurica

为了探讨外源过氧化氢(H_(2)O_(2))对水曲柳体胚发生过程中外植体内部抗氧化物质、抗氧化酶、一氧化氮(NO)等的影响,以成熟水曲柳子叶胚为外植体诱导体胚发生,通过对体胚发生过程中不同时间段的外植体取材,测定其内部生理变化,分析外源H_(2)O_(2)对水曲柳内部生理生化的影响。结果表明:外源H_(2)O_(2)的添加,对水曲柳体胚发生过程中还原性抗坏血酸(ASA)的质量摩尔浓度的影响主要在中后期阶段(42 d),且H_(2)O_(2)添加组高于对照组2.14%,对还原性谷胱甘肽(GSH)的影响在前期阶段(14 d),H_(2)O_(2)添加组是对照组的3.23倍;外源H_(2)O_(2)处理提高外植体H_(2)O_(2)的质量摩尔浓度,在14 d时,外源H_(2)O_(2)处理和对照的H_(2)O_(2)质量摩尔浓度相差较大,H_(2)O_(2)添加组是对照组的3.77倍;外源H_(2)O_(2)处理降低了丙二醛(MDA)质量摩尔浓度,且在7 d时,对照组显著高于H_(2)O_(2)添加组23.40%;外源H_(2)O_(2)前期降低一氧化氮和一氧化氮合酶(NOS)活性,后期对其起促进作用;外源H_(2)O_(2)处理对硝酸还原酶(NR)的作用与一氧化氮和一氧化氮合酶(NOS)活性完全相反。因此外源H_(2)O_(2)对水曲柳体胚发生中外植体抗氧化的各生理指标具有阶段性的影响。

In order to explore the effects of exogenous hydrogen peroxide(H_(2)O_(2)) on antioxidants, antioxidant enzymes and nitric oxide(NO) in explants during somatic embryogenesis of Fraxinus mandshurica, mature cotyledon embryos of F. mandshurica were used as explants to induce embryogenesis, and the effects of exogenous H_(2)O_(2)on the internal physiology and biochemistry of F. mandshurica were analyzed by sampling explants at different time intervals during somatic embryogenesis and measuring their internal physiological changes. The effect of exogenous H_(2)O_(2)addition on the mass molar concentration of reduced ascorbic acid(ASA) during somatic embryogenesis of F. mandshurica was mainly in the middle and late stages(42 d), and the effect of H_(2)O_(2)addition group was 2.14% higher than that of the control group. The effect on reduced glutathione(GSH) was in the early stage(14 d), and the effect of H_(2)O_(2)addition group was 3.23 times that of the control group. Exogenous H_(2)O_(2)treatment increased the mass molar concentration of H_(2)O_(2)in explants. On the 14 th day, the mass molar concentration of H_(2)O_(2)in exogenous H_(2)O_(2)treatment and control was quite different, and the H_(2)O_(2)addition group was 3.77 times of the control group. The treatment of exogenous H_(2)O_(2)reduced the mass molar concentration of malondialdehyde(MDA), and the content of MDA in control group was 23.40% higher than that in H_(2)O_(2)group on the 7 th day. Exogenous H_(2)O_(2)decreased the activity of nitric oxide and nitric oxide synthase(NOS) in the early stage and promoted it in the later stage. The effect of exogenous H_(2)O_(2)on nitrate reductase(NR) was completely opposite to nitric oxide and nitric oxide synthase(NOS) activities. Therefore, exogenous H_(2)O_(2)has a phased effect on the physiological indexes of antioxidant in explants of F. mandshurica somatic embryogenesis.