NaCl胁迫下紫花苜蓿幼苗抗氧化酶活性的研究

以紫花苜蓿品种金皇后(Medicago sativa L.‘Golden Empress’)为试验材料,用不同浓度NaCl(0,40,80,120和160mmol·L^-1)对其幼苗进行胁迫处理,分别对叶片和根部的超氧阴离子自由基(O₂^·-)、丙二醛(MDA)、过氧化物酶(POD)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸(Vc)和总抗氧化能力(T-AOC)等指标进行测定,旨在揭示紫花苜蓿幼苗地上、地下部分对盐胁迫的反应及抗氧化防御机制,为苜蓿耐盐性评价及新品种选育提供理论依据。结果表明:随着NaCl盐浓度增加,苜蓿根中O₂^·-和Vc先增加后减少,MDA含量和POD活性增加,SOD,CAT和T-AOC活性减少;苜蓿叶片中O₂^·-先增加后减少,MDA,Vc含量和SOD活性增加,POD,CAT和T-AOC活性减少。综合表明,相对于地上部分来说,盐对苜蓿幼苗根系的伤害更大。

Antioxidant Enzymes Activities of Medicago sativa L.Seedling under Salt Stress

To explore the responses of alfalfa(Medicago sativa L.’Golden Empress’) to salt stress,provide the scientific evaluation of alfalfa salt tolerance,antioxidant defense mechanisms of alfalfa seedling were treated.The antioxidant enzymes activities(Superoxide,MDA,POD,SOD,CAT,Vc and T-AOC) in alfalfa leaves and roots under different NaCl stress(0,40,80,120 and 160 mmol·L-1) were measured.Results showed that both superoxide and Vc levels initially increased then decreased while MDA and POD increased but SOD,CAT and T-AOC decreased in alfalfa root.However,superoxide levels initially increased then decreased,MDA,Vc and SOD increased,POD,CAT and T-AOC decreased in leaves of alfalfa under different NaCl stress.Comprehensive analysis showed that the roots of alfalfa seedlings experienced more serious salt damage compared to aboveground parts.