镉砷复合污染条件下镉低吸收水稻品种对镉和砷的吸收和累积特征

为探索镉(Cd)、砷(As)复合污染稻田下不同水稻品种对Cd、As的吸收和累积特征,选取4个低Cd吸收品种(金优463、金优268、金优433和株两优189)和2个当地主栽品种(五丰优111和马坝油毡),在广东韶关红壤区Cd、As复合污染稻田开展大田试验,调查和测定水稻的生长状况以及对Cd、As的吸收与转运情况。结果表明,参试6个水稻品种产量存在显著差异,2个当地主栽品种产量显著高于4个低Cd吸收品种。当地主栽品种马坝油毡籽粒Cd含量显著高于其他品种且超过国家污染物限量标准值(0.2 mg·kg~(-1)),其余品种Cd含量均未超标;6个品种As含量均超过国家标准值(0.2 mg·kg~(-1)),其中金优268籽粒Cd、As含量均为最低值,分别为0.05、0.31 mg·kg~(-1)。相关分析表明,品种间对Cd、As的富集能力和各部位的转运能力存在差异,其中低Cd吸收品种体内Cd从颖壳向籽粒的转运能力较低。因此,为同时降低Cd、As复合污染土壤中水稻籽粒Cd、As含量,在开展低重金属吸收品种选择研究时,需要同时考虑低Cd和低As两种因素。

Cd and As absorption and transport characteristics of rice in a paddy field co-contaminated by Cd and As

To explore safe methods to produce rice grown in paddy soil contaminated by Cd and As, this study selected six varieties of rice(four with low Cd absorption and two local varieties), and carried out field experiments in paddy soil contaminated by Cd and As in the red soil region of Shaoguan, Guangdong Province. The growth trends and characteristics of Cd and As absorption and transfer in low-absorption varieties and local varieties were evaluated. The results showed significant differences of yield among the different kinds of rice; the yields of the local varieties were significantly higher than those of the low-absorption varieties. Cd content in the low-absorption varieties was signifi cantly lower than in the local varieties, and As content of all the varieties was higher than the national standard(0.2 mg·kg^-1). Cd and As content(0.05 mg·kg^-1 and 0.31 mg·kg^-1 respectively) were lowest in variety Jinyou268. Correlation analysis showed that the transport ability from shell to grain for low-absorption varieties was lower than that for the local varieties. Therefore, to reduce Cd and As content in rice which is growing in Cd-and As-contaminated paddy soil, it is important to select rice varieties with low Cd as well as low As absorption capacities.