不同玉米品种镉积累及运移差异性研究

摘要

为筛选出低积累镉(Cd)的玉米品种,选取25个玉米品种,在Cd污染耕地上进行田间试验,研究Cd在不同玉米品种植株内的积累、转运和富集差异性.结果表明,21个玉米品种籽粒Cd含量符合GB 2715-2005《粮食卫生标准》(≤0.1 mg/kg),但只有济单7号、农华101、郑单136、郑韩358、郑单958、蠡玉37、蠡玉13、先玉335八个品种符合NY 861-2004《粮食及制品中铅、铬、镉、汞、硒、砷、铜、锌等8种元素限量》(≤0.05 mg/kg).玉米不同器官Cd含量由高到低依次为根、茎叶、籽粒.玉米对重金属的运移及积累研究结果进一步证实,籽粒Cd积累的品种差异主要在于Cd从茎叶向籽粒中转移的能力.8个Cd低积累特性品种从根系向籽粒的Cd转运系数平均为0.002 9,籽粒对土壤中Cd的富集系数平均为0.007 1.其中,济单7号和农华101具有成为Cd低积累特性品种的潜力.%Field experiment in cadmium(Cd) polluted farmland was conducted to study differences in Cd transportation and accumulation among cultivars by using twenty-five maize cultivars.The results showed that twenty-one cultivars of grain Cd content could meet the hygienic standard for grains GB 2715-2005(0.1 mg/kg or less),but only eight cultivars(Jidan 7 and Nonghua 101,Zhengdan 136,Zhenghan 358,Zhengdan 958,Liyu 37,Liyu 13,Xianyu 335) could reach the hygienic limit standard for grains NY 861-2004(0.05 mg/kg or less).The contents of the Cd for different maize organs in descending order were the root,the stem leaf,and the grain.Further study on the transportation and accumulation of heavy metal confirmed that the differences among cultivars in grain Cd content mainly depended on the Cd transfer capacity from the stem leaf to the grain.These eight cultivars had an average transport coefficient from root to seed of 0.002 9 and enrichment coefficient for seed of 0.007 1.Among them,Jidan 7 and Nonghua 101 have low-accumulation characteristics.