冷冻逆境中清除活性氧(ROS)对小麦抗寒性具有重要作用.文章采用3个抗寒性不同小麦品种(东农冬麦1号、济麦22和中国春),通过人工冷冻和田间越冬试验,分析不同冷冻温度下分蘖节中抗氧化物及H:O:、MDA变化,结果表明,随着温度下降,分蘖节H:O:含量持续上升,抗寒性强小麦品种H:O:含量较低;在＜-10℃之前MDA含量快速上升,表现应激反应,降低至较低水平,深度冷冻时含量上升,抗寒性强品种MDA含量低于不抗寒品种;分蘖节中POD酶活性和GSH含量在较高水平持续时间长,抗寒品种高于不抗寒品种;SOD和CAT酶活性均快速上升后持续降低,CAT酶活性品种间差异显著(P＜0.05);在APX酶活性与ASA含量上,品种间差异在田间试验中保持至12月14日.H2O2含量持续上升与CAT和SOD酶活性下降有关.各抗氧化物质均可防止脂质过氧化,利于增强小麦抗寒性.小麦抗氧化物质遗传差异可作为培育强抗寒冬小麦品种选择依据.%ROS scavenging played a significant role in wheat freezing resistant under freezing stress.Previous studies focused much on the changes of ROS scavenging agents,and few researches reported on.In this study,we applied artificial cold treatment in the experiment and natural overwintering treatment in the field to assay the variation of the antioxidants,H2O2 and MDA among three wheat varieties(Dongnongdongmai1,Jimai22 and Chinese Spdng) under freezing stress.With the temperature decrease,the content of H2O2 in the tilledng node showed a steady rising trend,and the strong cold hardiness cultivar had lower H2O2 compared to cold sensitive cultivar.MDA had a quick increase by cold stimulation upon-10 ℃,manifested as a stress and then desending to a lower level,and strong cold hardiness cultivar showed a lower content compared to cold sensitive cultivar when the temperature continually fell.POD enzyme activities and GSH content in the crown showed a higher level in strong cold hardiness cultivar than those in cold sensitive cultivar.The enzyme activities of SOD and CAT had a quick increase then a decrease trend,and showed obvious differences among wheat varieties (P＜0.05).APX enzyme activities and ASA content showed a distinct fluctuation among wheat varieties until Dec.14 in field test.These results indicated the increased H2O2 had a relationship with the decreased enzyme activities of CAT and SOD.In addition,the antioxidants produced positive effect on avoiding lipid peroxidization,and had benefit on plant cold resistance.The differences among wheat varieties could be used as references for winter wheat breeding.
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