Soil Science, University of Rostock, Justus-von-Liebig-Weg 6, D-18051 Rostock, Germany.
Sci Total Environ. 2011 Sep 1;409(19):4094-100. doi: 10.1016/j.scitotenv.2011.06.038. Epub 2011 Jul 18.
Under changing redox conditions some plants create plaques at their root surface, which may affect the mobility and uptake of As and heavy metals but it is unknown to what extent this also holds true for willows in contaminated floodplain soils. Therefore, willow roots were sampled from a phytoremediation trial in the contaminated floodplain of the river Elbe (Germany), cryofixed, freeze-dried, and cross sections were mapped for the distribution of As, Ca, Cu, Fe, K, Mn, Ni, S and Zn by synchrotron based X-ray fluorescence spectroscopy. The elements Ca, Cu, Ni, S and Zn were concentrated in the aerenchymatic tissue, and not associated with Fe and Mn. Mixed Fe-Mn plaques covered the surface of the willow roots and As was accumulated in these plaques. The observed association pattern between As and Fe was explained by the different sorption/desorption properties of As(III) and As(V). The Cu and Zn intensities were not associated with the intensity of Fe in the plaque, which seems to be a willow-specific difference compared to other wetland plants. These results suggested that willows are especially suited to stabilize low-phytoextractable elements like Cu and As in their roots and rhizosphere. Thus, short rotation coppicing of willows may be a practical approach to mitigate the adverse effects of floodplain soil contamination.
在氧化还原条件变化的情况下，一些植物会在其根部表面形成斑块，这可能会影响砷和重金属的迁移和吸收，但目前尚不清楚这在受污染的洪泛区土壤中的柳树中究竟有多大程度上适用。因此，从易北河（德国）受污染洪泛区的植物修复试验中采集了柳树根，经过冷冻固定、冷冻干燥，并用同步加速器基 X 射线荧光光谱法对砷、钙、铜、铁、钾、锰、镍、硫和锌的分布进行了横截面映射。钙、铜、镍、硫和锌元素集中在通气组织中，与铁和锰无关。混合的铁-锰斑块覆盖在柳树根的表面，砷则积累在这些斑块中。观察到的砷与铁之间的关联模式可以用砷(III)和砷(V)的不同吸附/解吸特性来解释。斑块中铁的强度与铜和锌的强度没有关联，这似乎是柳树与其他湿地植物相比的一个特有差异。这些结果表明，柳树特别适合在其根部和根际稳定低植物可提取的元素，如铜和砷。因此，柳树的短轮伐期造林可能是减轻洪泛区土壤污染不利影响的一种实用方法。
