Rice is more efficient in arsenite uptake and translocation than wheat and barley
Rice is more efficient in arsenite uptake and translocation than wheat and barley
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DOI：
10.1007/s11104-009-0074-2
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发表时间：
2010-03-01
期刊：
影响因子：
4.9
通讯作者：
Zhao, Fang-Jie
中科院分区：
文献类型：
--
作者：
Su, Yu-Hong;McGrath, Steve P.;Zhao, Fang-Jie
水稻是砷（As）的有效积累，从而对人类和动物构成潜在的健康风险。由于亚砷酸盐的动员，淹水水稻土中的砷生物利用度得到提高，但水稻也可能比其他谷类作物具有更大的吸收和转运亚砷酸盐的内在能力。为了验证这一假设，水稻、小麦和大麦分别暴露于5 μ M砷酸盐或亚砷酸盐环境24 h，测定了木质部汁液和营养液中砷的吸收和分布以及砷的形态。不论向植株提供何种形式的砷，水稻在茎部积累的砷都比小麦或大麦多。水稻对亚砷酸盐的吸收是小麦或大麦的两倍，而水稻和小麦对砷酸盐的吸收相似，大麦对砷酸盐的吸收大约少三分之一。砷酸盐处理比砷酸盐处理的砷从根向茎部的转运效率更高，且在两种处理中，水稻的转运效率最高。三种植物木质部液中砷的主要种类为亚砷酸盐（86-97%）。在砷酸盐处理的植物中，水稻、小麦和大麦木质部汁液中砷的含量分别为84%、45%和63%。在暴露于砷酸盐的所有三种植物物种中也观察到砷酸盐向外部介质的外排。结果表明，水稻对亚砷酸盐的吸收和转运效率高于小麦和大麦，这可能是通过硅的高效途径实现的。
Rice is efficient at arsenic (As) accumulation, thus posing a potential health risk to humans and animals. Arsenic bioavailability in submerged paddy soil is enhanced due to mobilisation of arsenite, but rice may also have an inherently greater ability to take up and translocate arsenite than other cereal crops. To test this hypothesis, rice, wheat and barley were exposed to 5 A mu M arsenate or arsenite for 24 h. Arsenic uptake and distribution, and As speciation in the xylem sap and nutrient solution were determined. Regardless of the As form supplied to plants, rice accumulated more As in the shoots than wheat or barley. Arsenite uptake by rice was double of that by wheat or barley, whereas arsenate uptake was similar between rice and wheat and approximately a third smaller in barley. The efficiency of As translocation from roots to shoots was greater when plants were supplied with arsenite than with arsenate, and in both treatments rice showed the highest translocation efficiency. Arsenite was the main species of As (86-97%) in the xylem sap from arsenite-treated plants of all three species. In the arsenate-treated plants, 84%, 45% and 63% of As in the xylem sap of rice, wheat and barley, respectively, was arsenite. Arsenite efflux to the external medium was also observed in all three plant species exposed to arsenate. The results show that rice is more efficient than wheat or barley in arsenite uptake and translocation, probably through the highly efficient pathway for silicon.