Altered arsenic availability, uptake, and allocation in rice under elevated temperature
Altered arsenic availability, uptake, and allocation in rice under elevated temperature
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DOI：
10.1016/j.scitotenv.2020.143049
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发表时间：
2021-01-17
影响因子：
9.8
通讯作者：
Neumann, Rebecca B.
中科院分区：
文献类型：
--
作者：
Farhat, Yasmine A.;Kim, Soo-Hyung;Neumann, Rebecca B.
气候变化预计将提高全球水稻种植区的生长温度。最近的研究表明，温度升高会增加水稻组织中的砷浓度，从而加剧对稻米质量和人类健康的现有威胁。然而，导致砷浓度增加的特定温度引起的植物-土壤系统变化仍不清楚，这些知识对于在更温暖的未来管理人类饮食砷暴露是必要的。为了阐明这些变化，我们在气候控制的生长室内建立了四种温度处理，并种植了水稻（Oryza sativa cv.）。M206)在装有砷浓度为7.7 mg kg（-1）的加利福尼亚水稻土的花盆中。这四个选择的温度模拟了IPCC对北加州的预测，在两次处理之间大约增加2.5摄氏度（夜间温度类似于降低2摄氏度）。我们观察到孔隙水、根铁斑块和植物组织中的砷浓度随着温度升高而增加。温度与稻谷砷呈线性正相关，且几乎全部以无机砷（ⅱ）的形式存在。不同处理的地上分配模式一致。我们发现编码OsABCC1转运体的基因没有上调，而OsABCC1转运体被认为对砷在液泡中的隔离很重要，从而防止砷转移到谷物中。在较高温度下生长的水稻单位铁膜（以[as]/[Fe]计）吸附的砷更多，表明温度可能影响砷对根膜的吸附。我们提出的证据表明，增加的土壤动员砷是驱动因素负责增加砷吸收到稻谷。蒸腾作用可以增加砷向根系的运输，也随着温度的升高而增加，但似乎起次要作用。我们系统的土壤砷浓度很低，这是典型的加州土壤砷浓度。我们的研究结果强调，在以前被认为是低风险的水稻系统中，生长温度升高可能会增加饮食砷暴露的风险。(C) 2020 Elsevier B.V.保留所有权利。
Climate change is expected to increase growing temperatures in rice cultivating regions worldwide. Recent research demonstrates that elevated temperature can increase arsenic concentrations in rice tissue, exacerbating an existing threat to rice quality and human health. However, the specific temperature-induced changes in the plant-soil system responsible for increased arsenic concentrations remain unclear and such knowledge is necessary to manage human dietary arsenic exposure in a warmer future. To elucidate these changes, we established four temperature treatments in climate-controlled growth chambers and grew rice plants (Oryza sativa cv. M206) in pots filled with Californian paddy soil with arsenic concentrations of 7.7 mg kg(-1). The four chosen temperatures mimicked IPCC forecasting for Northern California, with a roughly 2.5 degrees C increase between treatments (nighttime temperatures similar to 2 degrees C cooler). We observed that arsenic concentrations in porewater, root iron plaque, and plant tissue increased in response to elevated temperature. There was a positive linear relationship between temperature and rice grain arsenic, almost all of which was present as inorganic As (Ill). Above-ground allocation patterns were consistent across treatments. We found no upregulation in the gene encoding the OsABCC1 transporter, believed to be important for arsenic sequestration in vacuoles and thereby preventing arsenic transfer to grain. Rice plants grown at higher temperatures had more adsorbed arsenic per unit of iron plaque (measured as [As]/[Fe]), indicating temperature may impact arsenic sorption to root plaque. We present evidence that increased soil mobilization of arsenic was the driving factor responsible for increased arsenic uptake into rice grain. Transpiration, which can increase arsenic transport to roots, was also heightened with elevated temperature but appeared to play a secondary role. Our system had low soil arsenic concentrations typical for California. Our findings highlight that elevated growing temperatures may increase the risk of dietary arsenic exposure in rice systems that were previously considered low risk. (C) 2020 Elsevier B.V. All tights reserved.