耐盐和非耐盐大麦幼苗叶片抗氧化及抗坏血酸-谷胱甘肽循环系统对NaCl胁迫的反应差异

摘要

[Objectives] The aim of this study was to compare the response differences of antioxidant and ascorbate-glutathione cycle system to NaCl stress between the salt tolerant and sensitive barley cultivars at the seedling stage.[Methods] A hydroponic experiment was conducted using salt-tolerant cultivar (12pj-118) and non-tolerant cultivar (12pj-045) of barley as materials.Six NaCl stress concentrations were set up,including 0,100,200,300,400 and 500 mmol/L.The plant samples were collected when the forth leaf emerged.The active oxygen metabolism,antioxidant enzyme activity and ascorbate glutathione cycle were determined.[Results] The results showed that the O2-production rate,H2O2 content and MDA content were increased gradually with the increase of NaCl levels,and the increased rates of the 12pj-118 were lower than those of the 12pj-045.The activities of SOD,POD,CAT,GR and APX,the contents of AsA and GSH and the ratios of AsA/DHA were increased at first and then decreased.The increased rates of the SOD,POD and CAT activities were much higher in the 12pj-118 under different NaCl concentrations at first,and reduced rates were lower later.The increased rates of APX and GR activities of 12pj-118 were higher than those of 12pj-045 under the same salt concentration,and the reduced rates were lower.Under different NaCl concentrations,the increased rates of the AsA contents and AsA/DHA ratios of 12pj-118 were higher than those of 12pj-045.The ratios of GSH/GSSG showed a wavy change in two barley cultivars,and the 12pj-118 was able to maintain high GSH contents and GSH/GSSG ratios under higher NaCl concentrations.These results indicated that the salt resistance of 12pj-118 was better than the 12pj-045.[Conclusions] The response of NaCl stress was different on antioxidant system and ascorbateglutathione cycle at the seedling stage.At a given range,with the increase of NaCl concentration,the increased rates of the SOD,POD,CAT,APX,GR,AsA and GSH of thel2pj-118 were much higher than those of the 12pj-045 under different NaCl concentrations,and reduced rates were lower.The results indicated that antioxidant activity and ascorbate glutathione cycle were closely related to salt tolerance of barley seedlings.%[目的]研究NaCl胁迫下,耐盐和非耐盐品系大麦幼苗叶片抗氧化系统及抗坏血酸-谷胱甘肽循环的反应差异.[方法]以耐盐品系12pj-118和非耐盐品系12pj-045为材料进行了水培试验.营养液中设定了6个NaCl浓度:0、100、200、300、400、500 mmol/L.在大麦苗生长至3叶1心时,取样分析测定叶片中活性氧代谢、抗氧化酶活性以及抗坏血酸-谷胱甘肽循环变化.[结果]随着NaCl胁迫的增加,2个品系的O2-产生速率、H2O2含量和MDA含量均逐渐增加,耐盐品系12pj-118的增幅均小于非耐盐品系12pj-045;SOD、POD、CAT、APX、GR活性、AsA含量、GSH含量和AsA/DHA比值均呈先上升后下降的趋势.12pj-118的SOD、POD、CAT活性在各NaCl浓度胁迫下的增幅大于12pj-045,降幅小于12pj-045;12pj-118的APX、GR活性在同一盐浓度胁迫下的增幅均大于非耐盐品系12pj-045,降幅小于12pj-045;在各NaCl浓度下,12pj-118的AsA含量和AsA/DHA比值较对照增幅均大于12pj-045;GSH/GSSG比值呈波状变化,12pj-118在较高NaCl浓度下,仍能够维持较高的GSH含量和GSH/GSSG比值.显示12pj-118较12pj-045有较强的耐盐性.[结论]耐盐和非耐盐品系大麦叶片抗氧化及抗坏血酸-谷胱甘肽循环系统在NaCl胁迫下的反应不同.在一定范围内,随着盐胁迫增强,耐盐品系12pj-118叶片SOD、POD、CAT、APX和GR活性、AsA和GSH含量增幅均大于非耐盐品系12pj-045,降幅小于12pj-045,表明叶片抗氧化及抗坏血酸-谷胱甘肽循环系统与大麦幼苗抗盐性密切相关.