Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou 310058, China.
Department of Health and Environmental Sciences, Xi'an Jiaotong-Liverpool University, Suzhou 215123, China.
J Hazard Mater. 2021 Apr 15;408:124913. doi: 10.1016/j.jhazmat.2020.124913. Epub 2020 Dec 20.
Global warming severely hinders both rice (Oryza sativa L.) quality and yield by increasing arsenic (As) bioavailability in paddy soils. However, details regarding As biotransformation and migration in the rice-soil system at elevated temperatures remain unclear. This study investigated the effects of increasing temperature on As behavior and translocation in rice grown in As-contaminated paddy soil at two temperature treatments (33 °C warmer temperature and 28 °C as control). The results showed that increasing temperature from 28 °C to 33 °C significantly favored total As, arsenite (As(III)) and arsenate (As(Ⅴ)) release into the soil pore-water. This increase in As bioavailability resulted in significantly higher As(III) accumulation in the whole grains at warmer treatment relative to the control. Moreover, the results suggest that increasing temperature to 33 °C promoted As(III) migration from the roots to the whole grains. Furthermore, the As(V)-reducing Xanthomonadales order and Alcaligenaceae family, and As(V) reductase-encoding arsC gene were enriched in the rhizosphere soils incubated at 33 °C. This suggests that the increase in As bioavailability in that treatment was due to enhanced As(V) reductive dissolution into the soil pore-water. Overall, this study provides new insights on how warmer future temperatures will exacerbate As accumulation in rice grains.
全球变暖通过增加稻田土壤中砷的生物利用度，严重阻碍了水稻（Oryza sativa L.）的品质和产量。然而，关于高温下水稻-土壤系统中砷的生物转化和迁移的细节仍不清楚。本研究在两种温度处理（33°C 升温处理和 28°C 对照）下，研究了温度升高对砷污染稻田中水稻砷行为和迁移的影响。结果表明，温度从 28°C 升高到 33°C 显著有利于总砷、亚砷酸盐（As(III)) 和砷酸盐（As(Ⅴ)) 释放到土壤孔隙水中。这种生物可利用砷的增加导致在较暖处理下整个谷物中 As(III) 的积累明显高于对照。此外，结果表明，温度升高到 33°C 促进了 As(III) 从根部向整个谷物的迁移。此外，根际土壤中黄单胞菌目和产碱杆菌科以及砷酸盐还原酶编码的 arsC 基因丰富。这表明，该处理中砷生物可利用度的增加是由于增强了 As(V)的还原溶解到土壤孔隙水中。总的来说，本研究提供了新的见解，即未来更高的温度将如何加剧水稻籽粒中砷的积累。
