【摘要】 土壤镉(Cd)污染是引起稻米镉污染的重要因素,但二者之间并非简单的线性关系。本文围绕植物根系、茎叶、穗轴和稻谷对Cd的拦截作用及其调控机理进行综述,表明:在长期的自然进化过程中,水稻的根茎叶组织和穗轴、颖壳、果皮、种皮等组织具备了识别必需元素和有害元素的特殊功能,能够把大量的Cd固定在营养体的细胞壁中,或封存在液泡中。经过各类细胞的层层拦截,只有极少数的Cd汇聚到穗轴中,穗轴中的Cd浓度与稻米中的Cd含量高度线性相关。籽粒灌浆成熟后,Cd主要分布在颖壳和富含蛋白质的糊粉层与胚中,淀粉中的Cd含量最低。水稻根系和节是Cd含量最高的营养器官。通过栽培措施和遗传调控,发掘和利用营养器官对Cd的拦截潜力和过滤功能,有助于降低稻米Cd污染风险。更多还原

【Abstract】 Cadmium(Cd)contamination in farmlands is an important factor causing rice cadmium pollution, but there is not a simple linear relationship between them. During the long process of natural evolution, rice organs including root, leaf, spike, glume, pericarp, seed coat and others have evolved the special function to discriminate essential elements from harmful ones. A large amount of cadmium is fixed in the cell walls of vegetative organs or compartmentalized in vacuoles. After many interceptions from miscellaneous cells, only a small amount of cadmium flows into the spike rachises. Cadmium concentration in rachises is positively and linearly correlated with cadmium content in rice grains. After grain filling and maturation, cadmium is mainly distributed in glume, aleurone layer and embryo with high protein. Starch has the lowest content of cadmium in grains. Rice roots and nodes have much higher cadmium concentration than other organs.There is a great potential in reducing the risk of cadmium pollution in rice grains by exploring the interception and filtration function of vegetative organs to cadmium through cultivation measures and genetic manipulation.更多还原