镉胁迫对不同品种玉米幼苗生长及生理特性的影响

Effects of cadmium stress on the growth and physiological characteristics of maize seedlings from different varieties

为探究不同品种玉米苗期对镉胁迫的响应差异,筛选出耐镉性较强的品种,选用4个玉米杂交种(京农科728、郑单958、正大999、豫单9953),通过水培的方法进行镉胁迫(6 mg/L CdCl2·2.5H2O)处理,在镉胁迫3、6、9、12 d后对4个玉米品种苗期的生长指标和生理指标进行检测分析,并采用主成分分析和隶属函数法进行耐镉性综合评价。结果表明:镉胁迫后4个品种幼苗的根长、株高、地上部干质量、地上部鲜质量、地下部干质量、地下部鲜质量和总叶绿素含量整体低于对照(蒸馏水处理),豫单9953在整个胁迫过程中叶片和根部的POD活性以及MDA含量高于对照组;镉胁迫下,与其他品种相比,豫单9953的株高、根长和干质量下降幅度较大,但其鲜质量受影响较小,且其叶片MDA含量增加幅度小,POD活性强。耐镉性综合评价结果显示,豫单9953、京农科728、正大999、郑单958的耐镉性依次减弱,豫单9953可作为耐镉性品种培育。

This study aimed to explore the differences of cadmium stress response in the different maize varieties seedling stage and screen out varieties with strong cadmium tolerance.The four maize hybrids Jingnongke728,Zhengdan958,Zhengda999 and Yudan9953 were selected in this study.Through laboratory hydroponics,they were treated with cadmium stress(6 mg/L CdCl2·2.5H2O).The growth indexes and physiological indexes of four maize varieties at seedling stage were detected and analyzed after 3,6,9 and 12 days of cadmium stress,and the comprehensive evaluation of cadmium tolerance was carried out using principal component analysis and membership function method.The results showed that the root length,plant height,dry and fresh weight and total chlorophyll content of the seedlings of the four varieties after cadmium stress were lower than those of the control(distilled water treatment),and the POD activity and MDA content of leaves and roots of Yudan9953 were higher than those of the control during the whole stress process.Under cadmium stress,Yudan9953 decreased significantly in plant height,root length and dry weight compared with other varieties,but its fresh weight was less affected,and its leaf MDA content increased less and POD activity was strong.The comprehensive evaluation results of cadmium tolerance showed that the cadmium tolerance of Yudan9953,Jingnongke728,Zhengda999 and Zhengdan958 weakened sequentially,and Yudan9953 could be cultivated as a cadmium-tolerant variety.