Department of Environmental Science, Policy, and Management, University of California-Berkeley, 130 Mulford Hall, Berkeley, CA 94720, USA.
Civil and Environmental Engineering, University of California-Berkeley, 410 O'Brien Hall, Berkeley, CA 94720, USA.
Sci Total Environ. 2022 Apr 20;818:151803. doi: 10.1016/j.scitotenv.2021.151803. Epub 2021 Nov 20.
Plant-soil interactions affect arsenic and nutrient availability in arsenic-contaminated soils, with implications for arsenic uptake and tolerance in plants, and leaching from soil. In 22-week column experiments, we grew the arsenic hyperaccumulating fern Pteris vittata in a coarse- and a medium-textured soil to determine the effects of phosphorus fertilization and mycorrhizal fungi inoculation on P. vittata arsenic uptake and arsenic leaching. We investigated soil arsenic speciation using synchrotron-based spectromicroscopy. Greater soil arsenic availability and lower nutrient content in the coarse-textured soil were associated with greater fern arsenic uptake, lower biomass (apparently a metabolic cost of tolerance), and arsenic leaching from soil, due to lower transpiration. P. vittata hyperaccumulated arsenic from coarse- but not medium-textured soil. Mass of plant-accumulated arsenic was 1.2 to 2.4 times greater, but aboveground biomass was 74% smaller, in ferns growing in coarse-textured soil. In the presence of ferns, mean arsenic loss by leaching was 195% greater from coarse- compared to the medium-textured soil, and lower across both soils compared to the absence of ferns. In the medium-textured soil arsenic concentrations in leachate were higher in the presence of ferns. Fern arsenic uptake was always greater than loss by leaching. Most arsenic (>66%) accumulated in P. vittata appeared of rhizosphere origin. In the medium-textured soil with more clay and higher nutrient content, successful iron scavenging increased arsenic release from soil for leaching, but transpiration curtailed leaching.
植物-土壤相互作用影响砷和养分在受砷污染土壤中的有效性，从而影响植物对砷的吸收和耐受以及土壤中砷的淋失。在为期 22 周的柱状实验中，我们在粗质地和中质地土壤中种植砷超富集蕨类植物蜈蚣草，以确定磷施肥和菌根真菌接种对蜈蚣草砷吸收和砷淋失的影响。我们使用基于同步加速器的光谱显微镜研究了土壤中砷的形态。粗质地土壤中较高的土壤砷有效性和较低的养分含量与较高的蕨类植物砷吸收、较低的生物量（显然是耐受的代谢成本）以及由于蒸腾作用降低导致的土壤砷淋失有关。蜈蚣草从粗质地土壤而不是从中质地土壤中积累砷。在粗质地土壤中生长的蕨类植物积累的砷的质量是中质地土壤中的 1.2 到 2.4 倍，但地上生物量小 74%。在有蕨类植物的情况下，与中质地土壤相比，粗质地土壤的砷淋失平均损失增加了 195%，与没有蕨类植物相比，两种土壤的淋失均减少。在中质地土壤中，有蕨类植物存在时，淋出液中的砷浓度更高。蕨类植物的砷吸收总是大于淋失。在蜈蚣草中积累的砷（>66%）主要来自根际。在中质地土壤中，粘土含量更高，养分含量更高，成功的铁螯合作用增加了土壤中砷的释放以进行淋失，但蒸腾作用限制了淋失。
