Lead (Pb) ranks among the most problematic environmental pollutants. Background contamination of soils is nearly ubiquitous, yet plant Pb accumulation is barely understood. In a survey covering 165 European populations of the metallophyte Arabidopsis halleri, several field samples had indicated Pb hyperaccumulation, offering a chance to dissect plant Pb accumulation. Accumulation of Pb was analysed in A. halleri individuals from contrasting habitats under controlled conditions to rule out aerial deposition as a source of apparent Pb accumulation. Several elemental imaging techniques were employed to study the spatial distribution and ligand environment of Pb. Regardless of genetic background, A. halleri individuals showed higher shoot Pb accumulation than A. thaliana. However, dose-response curves revealed indicator rather than hyperaccumulator behaviour. Xylem sap data and elemental imaging unequivocally demonstrated the in planta mobility of Pb. Highest Pb concentrations were found in epidermal and vascular tissues. Distribution of Pb was distinct from that of the hyperaccumulated metal zinc. Most Pb was bound by oxygen ligands in bidentate coordination. A. halleri accumulates Pb whenever soil conditions render Pb phytoavailable. Considerable Pb accumulation under such circumstances, even in leaves of A. thaliana, strongly suggests that Pb can enter food webs and may pose a food safety risk.

中文翻译：

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拟南芥显示出与锌在空间上分开的铅和叶片铅积累的超生物指示剂行为。

铅（Pb）是最成问题的环境污染物之一。土壤的背景污染几乎无处不在，但对植物铅的积累却知之甚少。在一项针对欧洲165种金属植物拟南芥种群的调查中，几个田间样本表明Pb富集度高，这为剖析植物Pb积累提供了机会。在受控条件下，通过对比生境中的A. halleri个体分析了Pb的积累，以排除空中沉积作为明显的Pb积累的来源。几种元素成像技术被用来研究铅的空间分布和配体环境。不论遗传背景如何，汉勒假单胞菌个体的茎中铅的积累均高于拟南芥。然而，剂量-反应曲线揭示的是指标，而不是过度蓄积的行为。木质部汁液数据和元素成像清楚地证明了铅在植物体内的迁移。在表皮和血管组织中发现最高的Pb浓度。铅的分布与高积累金属锌的分布不同。大多数Pb在双齿配位中被氧配体结合。每当土壤条件使植物能够利用铅时，哈氏曲霉就会积累铅。在这种情况下，即使在拟南芥叶中也积累了大量的Pb，这强烈表明Pb可能进入食物网，并可能构成食品安全风险。铅的分布与高积累金属锌的分布不同。大多数Pb在双齿配位中被氧配体结合。每当土壤条件使植物能够利用铅时，哈氏曲霉就会积累铅。在这种情况下，即使在拟南芥叶中也积累了大量的Pb，这强烈表明Pb可能进入食物网，并可能构成食品安全风险。铅的分布与高积累金属锌的分布不同。多数Pb在双齿配位中被氧配体结合。每当土壤条件使植物能够利用铅时，哈氏曲霉就会积累铅。在这种情况下，即使在拟南芥叶中也积累了大量的Pb，这强烈表明Pb可能进入食物网，并可能构成食品安全风险。