Water management impacts the soil microbial communities and total arsenic and methylated arsenicals in rice grains.
Water management impacts the soil microbial communities and total arsenic and methylated arsenicals in rice grains.
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DOI：
10.1016/j.envpol.2019.01.043
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发表时间：
2019-01
影响因子：
8.9
通讯作者：
Ming Wang;Zhong Tang;Xueping Chen;Xin Wang;Wuxian Zhou;Zhu Tang;Jun Zhang;F. Zhao
中科院分区：
文献类型：
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作者：
Ming Wang;Zhong Tang;Xueping Chen;Xin Wang;Wuxian Zhou;Zhu Tang;Jun Zhang;F. Zhao
稻田土壤中准金属砷（As）的生物有效性受砷和铁（Fe）和硫（S）等其他元素的微生物循环控制，而这些元素又受稻田水分管理的强烈影响。在这项研究中，我们通过在地质砷污染的土壤中种植水稻来评估水管理如何影响砷的生物利用度。我们确定了土壤孔隙水中的砷形态以及相关微生物群落的多样性。与好氧处理相比，连续淹水增强了铁和砷的释放，增加了稻谷中亚砷酸盐（As(III)）和甲基化砷的浓度。与连续淹水处理相比，好氧处理的谷物中总无机砷和有机砷分别降低了84%和81%。淹水根际土壤中 Fe(III) 还原菌 (FeRB) 的数量增加。土壤中 FeRB 的丰度与 Fe 和 As 的溶解相关。在定量的As转化基因中，As(III)氧化的theaioA基因和As(III)甲基化的arsM基因最丰富。 ThearsMcopy数与dsrB（异化（双）亚硫酸盐还原酶β-亚基）水平呈正相关，表明异化硫酸盐还原菌（SRB）可能在土壤中二甲基砷酸（DMAs（V））生产中发挥重要作用。我们的结果表明，根际 FeRB 和 SRB 数量的减少导致砷的生物利用度降低，并在有氧条件下甲基化砷的产生减少。
The bioavailability of the metalloid arsenic (As) in paddy soil is controlled by microbial cycling of As and other elements such as iron (Fe) and sulfur (S), which are strongly influenced by water management in paddy fields. In this study, we evaluated how water management affects As bioavailability by growing rice plants in a geogenic As-contaminated soil. We determined As speciation in soil porewater and the diversity of the associated microbial community. Continuous flooding enhanced the release of Fe and As and increased arsenite (As(III)) and methylated As species concentrations in the rice grain compared with aerobic treatment. Total inorganic and organic As in the grain was 84% and 81% lower, respectively, in the aerobic treatment compared with the continuous flooding treatment. The amounts of Fe(III)-reducing bacteria (FeRB) increased in the flooded rhizosphere soil. The abundance of FeRB in the soil correlated with the dissolution of Fe and As. Among the As-transformation genes quantified, theaioAgene for As(III) oxidation andarsMgene for As(III) methylation were most abundant. ThearsMcopy number correlated positively with the levels ofdsrB(dissimilatory (bi) sulfite reductaseβ-subunit), suggesting that dissimilatory sulfate-reducing bacteria (SRB) may play an important role in dimethylarsenate (DMAs(V)) production in soil. Our results show that decreased populations of rhizosphere FeRB and SRB contributed to a lower bioavailability of As, and decreased production of methylated arsenicals under oxic conditions.