水稻品种及其器官对土壤重金属元素Pb、Cd、Hg、As积累的差异

在土壤中添加重金属元素Pb、Cd、Hg、As,研究43个不同类型水稻品种(系)成熟后不同器官重金属元素的含量差异。研究结果表明,Pb、Cd、Hg、As主要在水稻植株根中大量富集,其次是茎叶,在稻谷和精米中富集量最低;通过富集系数的比较,发现水稻对Cd富集能力最强,其次是Hg,然后是Pb,最低是As。不同类型的水稻品种对重金属元素的吸收规律为:①Pb在常规籼稻稻米和稻谷中的含量显著高于在粳稻和杂交稻中的含量,而茎叶中Pb含量在不同类型品种间不存在显著差异。②Cd在不同类型品种和不同器官中的含量均存在显著差异,在常规籼稻精米、稻谷中的含量最高,在杂交稻精米和稻谷中的含量居中,在常规粳稻中的含量最低;杂交稻和常规籼稻茎叶中Cd含量高于粳稻;而粳稻根中Cd含量显著高于籼稻和杂交稻。③Hg在不同类型品种精米中的含量之间存在显著差异,以杂交稻精米中汞含量最高,而在稻谷和茎叶中Hg含量不同品种类型之间不存在显著差异。④在不同品种类型之间精米和稻谷中As含量存在显著差异,常规稻和杂交稻含量较高,而茎叶As含量在不同品种类型之间不存在显著差异。

Differences in Accumulation and Distribution of Pb, Cd, Hg and As in Rice Cultivars and Their Organs(Oryza sativa L.)

Forty-three rice varieties were selected randomly to test and compare the difference in accumulation and distribution of heavy metal elements Pb,Cd,Hg and As at maturing stage.The four metals concentrations decreased rapidly from roots to grains along rice plants,the lest in paddy grains and milled grains.The highest accumulation of heavy metals in rice happened on Cd, then Hg and Pb in turn,the lowest As.The concentrations of Pb in the paddy grains and milled grains of conventional indica rice were higher than those of japonica rice and hybrid rice.However,there was no significant difference in Pb concentration between different genotypes of rice.Cd was detected the highest contents in the paddy grains and milled grains of conventional indica rice,the moderate contents in those of hybrid rice and the lowest contents inconventional japonica rice,while it wasaccumulated the most in the stems and leaves of hybrid rice and indica rice,and the most in the roots of japonica rice.For metal Hg,it had the highest content in the milled grains of hybrid rice and no significant difference in its content could be found out in the stems and leaves of different genotypes of rice.However for As,it had the highest content in the paddy grains and milled grains of conventional rice and hybrid rice and there was no significant difference in the stems and leaves of different genotypes of rice.