In recent years,wheat(Triticum aestivum L.)suffered serious heavy metal pollution and its yield decreased.In this study, a hydroponics experiment was conducted to study the genotypic differences of Cu tolerance and the activity of glutathione-related enzymes to elucidate the anti-oxidative response mechanism under Cu stress in main wheat cultivars of China. 37 wheat cultivars from different main planting area of China were selected and exposed to Cu stress for 96 h. 6 growth and physiological indexes in young roots were measured, and a comprehensive evaluation for wheat Cu resistance was achieved through correlation analysis, subordinate function analysis and median clustering method. Based on the average value of subordinate function values, 37 wheat cultivars were classified into three groups. The high Cu resistant group was consisted of seven varieties including Liangxing 99 and Jimai 22. The medium Cu resistant group was made up of 22 cultivars, such as Zhongmai 1, Shinong 952 and so on. 8 varieties such as Xinong 979 and Luomai 23 belonged to the weak Cu resistant group. Four varieties from the high Cu resistant and the weak Cu resistant groups respectively were selected and the activities of root GSTs, GR and GSH-PX under Cu stress were measured. The results showed that there were great differences in the change patterns of the three glutathione-related enzymes. The GSTs activity of Luomai 23 and Xinong 979 was significantly higher than that of the other two cultivars compared with control. The activities of GR and GSH-PX in high Cu-resistant wheat cultivars were higher than those in weak Cu-resistant wheat cultivars while there were great differences in the change between the weak Cu-resistant wheat cultivars. The results suggested that the same enzyme may have different degrees of tolerance to Cu stress among different wheat cultivars and the response mechanisms to Cu stress of wheat also exhibited genotype differences.%近年来,小麦(Triticum aestivum L.)受重金属污染导致的减产和污染问题十分严峻.为明确中国不同主栽区小麦品种耐铜(Cu)性,探讨谷胱甘肽相关酶在耐性不同品种间的活性差异,进而揭示小麦在Cu胁迫下的抗氧化反应机制,采用室内水培法,选择来自不同主栽区的37个小麦品种,进行重金属Cu胁迫处理,96 h后测定幼根的6个生长生理指标,运用隶属函数法计算其平均隶属度值,再结合中位数聚类分析法,将参试品种分为3类:(Ⅰ)强耐Cu型,包括良星99、济麦22等7个品种;(Ⅱ)中等耐Cu型,包括众麦1号、石农952等22个品种;(Ⅲ)弱耐Cu型,包括西农979、洛麦23等8个品种.进一步选取强耐Cu型(济麦22、科农9204)和弱耐Cu型(西农979、洛麦23)各两个品种,测定幼根谷胱甘肽硫转移酶(GSTs)、谷胱甘肽还原酶(GR)和谷胱甘肽过氧化物酶(GSH-PX)活力.结果表明,Cu 胁迫下,3种谷胱甘肽相关酶的变化规律存在较大差异.与CK相比,Cu胁迫下,GSTs在洛麦23和西农979的活力显著高于其他2个品种;GR和GSH-PX在强耐Cu型品种间的活力均升高,与其他2个品种差异显著,而在弱耐Cu型小麦品种间变化不尽相同,这暗示了同一种酶在不同小麦品种间耐受Cu的质量浓度可能不同,其响应Cu胁迫机制存在一定的基因型差异.
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