Department of Plant & Soil Sciences, University of Delaware, Newark, DE, 19716, USA.
Department of Plant & Soil Sciences, University of Delaware, Newark, DE, 19716, USA.
Sci Total Environ. 2018 May 15;624:1360-1368. doi: 10.1016/j.scitotenv.2017.12.207. Epub 2017 Dec 27.
An emerging approach to limit rice uptake and grain As targets the shared root-uptake pathway between As(III) and Si. We amended rice paddy mesocosms with Si-rich rice residues (husk and husk char) or silicate fertilizer to evaluate the impact of different Si sources on rice uptake of Si and As including As speciation in grain under background soil As. For a systems-approach, we also measured plant biomass, rice yield, porewater chemistry, mesocosm-scale CH and CO fluxes, plant concentrations of nutrients and metals, and root Fe plaque mineralogy. Relative to the control, Si-rich amendments increased plant Si and proportion of ferrihydrite on root plaque, decreased root-to-shoot Mn transfer and As uptake, and shifted grain As from inorganic to organic As. The charred husk treatment, which resulted in the most Si accumulation in rice shoots, most decreased plant As and grain As. Husk treatment led to the highest CH emissions, but all treatments had lower CH emissions than has been reported for straw treatments. Collectively, Si-rich amendments performed similarly across several biogeochemical benchmarks, with charred husk best restricting plant As, suggesting these amendments can be used to reduce toxicity of As from rice grain while maintaining yield.
一种新兴的方法来限制水稻对砷的吸收和降低其在谷物中的含量，是针对砷（III）和硅的共同根系吸收途径。我们通过向富含硅的水稻残体（稻壳和稻壳炭）或硅肥添加到稻田微宇宙中，来评估不同硅源对水稻吸收硅和砷的影响，包括在背景土壤砷条件下谷物中砷的形态。为了进行系统研究，我们还测量了植物生物量、水稻产量、孔隙水化学、微宇宙尺度 CH 和 CO 通量、植物养分和金属浓度以及根铁膜的矿物学。与对照相比，富硅添加剂增加了植物硅和根铁膜上的水铁矿比例，减少了根到茎叶的锰转移和砷吸收，并将谷物中的砷从无机砷转化为有机砷。稻壳炭处理导致水稻地上部积累的硅最多，植物砷和谷物砷含量最低。稻壳处理导致 CH 排放量最高，但所有处理的 CH 排放量均低于秸秆处理的报道。总的来说，富硅添加剂在几个生物地球化学基准方面表现相似，稻壳炭处理能最好地限制植物砷含量，这表明这些添加剂可用于降低来自水稻的砷的毒性，同时保持产量。
