江汉平原水稻中重金属元素累积效应及迁移运转特征

Cumulative Effects of Heavy Metal Elements in Rice in Jianghan Plain and Their Migration and Transfer Characteristics

以江汉平原潜江市、天门市、钟祥市、仙桃市调查区水稻根系、茎叶、稻米及其配套根系土为研究对象,分析了研究区水稻中重金属元素的累积效应和不同部位的迁移运转规律。结果表明,重金属元素在水稻中的富集程度差异较大,Zn、Cd、Cu在水稻中明显富集;稻米中Cd与Zn、Ni对水稻籽实吸收重金属的影响较大;土壤pH与水稻Cd、Zn、Ni的富集有一定的负相关关系。水稻重金属元素均在根系中最富集,茎叶次之,籽实最低,其中Zn元素在根系、茎叶、籽实中含量最为稳定,而As元素在水稻各部位中变差最大。大米中Cd元素从茎叶内吸收的比例超过100%,水稻的根系在吸收过程中As和Cd容易迁移到体内,在其根部富集,出现根部重金属含量超富集的现象,表明As、Cd等元素在研究区内是影响水稻安全的主要因素。

Taking the rice roots,stems,leaves,rice and their supporting root soils in Qianjiang City,Tianmen City,Zhongxiang City and Xiantao City of Jianghan Plain as research objects,the cumulative effects of heavy metal elements in rice in the study area and the laws of migration and movement in different parts were analyzed.The results showed that the degree of enrichment of heavy metal elements in rice varies widely,and Zn,Cd,and Cu were significantly enriched in rice;Cd,Zn and Ni in rice had a greater effect on the absorption of heavy metals by rice seeds;soil pH had a negative correlation with the enrichment of Cd,Zn and Ni in rice.The heavy metal elements of rice were the most abundant in the root system,followed by the stems and leaves,and the seeds were the lowest.Among them,the content of Zn was the most stable in the roots,stems,leaves and seeds,and As had the largest variation in various parts of rice.The ratio of Cd element absorption from stems and leaves in rice was more than 100%.During the absorption process of rice roots,As and Cd easily migrated into the body,and their roots were enriched,resulting in the phenomenon of super-rich root metal content,indicating that As,Cd and other elements were the main factors affecting rice safety in the study area.