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以小麦绵农4号幼苗叶片为试材,以-0.6 MPa聚乙二醇-6000(PEG-6000)处理造成渗透胁迫,研究了外源亚精胺(Spd)预处理对小麦相对含水量(RWC)、H2O2含量、丙二醛(MDA)含量、电解质渗漏以及超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)活性的影响。在渗透胁迫处理前进行2 d Spd预处理,每天用含有0.02%吐温-80的0.2 mmol/L Spd溶液在8 d龄幼苗叶上喷施,用含有0.2 mmol/L Spd的1/2浓度的Hoagland营养液浇灌根部;以含有0.02%吐温-80的蒸馏水喷叶和1/2浓度的Hoagland营养液浇灌根部作对照。随着渗透胁迫的进行,对照幼苗叶中的RWC降低,膜脂过氧化,H2O2含量和电解质渗漏增加,Spd预处理则延缓了这些变化。渗透胁迫增加了对照幼苗叶中SOD、POD和APX活性,降低了CAT活性。在整个渗透胁迫过程中,经过Spd预处理的小麦幼苗叶片的POD、CAT和APX,特别是SOD活性均高于对照。说明Spd预处理可以诱导和维持较高的抗氧化酶活性,降低H2O2浓度,减轻由渗透胁迫造成的氧化伤害,提高渗透胁迫下小麦幼苗的抗氧化能力。
The effects of exogenous spermidine (Spd) pretreatment on the relative water content of wheat (Triticum aestivum L.), wheat (Triticum aestivum L.) seedling, were studied under osmotic stress with -0.6 MPa PEG-6000. RWC, H2O2 content, malondialdehyde (MDA) content, electrolyte leakage, as well as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase ) Activity. Spd pretreatment was carried out for 2 days before osmotic stress treatment. Spray solution of 0.2 mmol / L Spd containing 0.02% Tween-80 was sprayed on the leaves of 8-day-old seedlings every day, Of Hoagland nutrient solution was applied to the roots of the roots. Roots were drenched with distilled water sprayed with Tween-80 at 0.02% and Hoagland nutrient solution at 1/2 concentration. As osmotic stress progressed, RWC decreased, membrane lipid peroxidation, H2O2 content and electrolyte leakage increased in control seedling leaves, whereas Spd pretreatment delayed these changes. Osmotic stress increased the activities of SOD, POD and APX in the leaves of control seedlings and decreased the CAT activity. During the whole process of osmotic stress, POD, CAT and APX, especially SOD activity of wheat seedling leaves pretreated with Spd were higher than those of the control. These results indicated that Spd pretreatment could induce and maintain high antioxidant enzyme activity, reduce the concentration of H2O2, alleviate the oxidative damage caused by osmotic stress and enhance the antioxidant capacity of wheat seedlings under osmotic stress.