Phloem transport of arsenic species from flag leaf to grain during grain filling.
Phloem transport of arsenic species from flag leaf to grain during grain filling.
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DOI：
10.1111/j.1469-8137.2011.03789.x
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发表时间：
2011-10
期刊：
影响因子：
--
通讯作者：
Meharg AA
中科院分区：
文献类型：
--
作者：
Carey AM;Norton GJ;Deacon C;Scheckel KG;Lombi E;Punshon T;Guerinot ML;Lanzirotti A;Newville M;Choi Y;Price AH;Meharg AA
将稻米中的砷降低到严重影响人类健康的水平以下的战略，需要建立稻米中砷积累的机制。因此，研究了剑叶砷形态向灌浆期水稻籽粒的再转运。砷的形态是在灌浆期通过剑叶传递的。利用同步辐射X射线荧光（SXRF）显微层析技术研究了晶粒内的空间卸载。此外，研究了锗酸（一种草酸类似物）对亚砷酸处理的穗中籽粒砷积累的影响。二甲基胂酸（DMA）和单甲基胂酸（MMA）非常有效地从剑叶再转运到水稻籽粒;砷酸盐的再转运较差，并迅速减少到亚砷酸盐的剑叶内;亚砷酸盐显示没有再转运。在晶粒内，DMA迅速分散，而MMA和无机砷仍然接近进入点。锗酸的加入并没有影响砷处理的穗粒砷。三维SXRF显微断层扫描提供了进一步的信息亚砷酸盐定位在水稻胚珠维管痕迹（OVT）。这些结果表明，无机砷是很难再动员，而有机物种很容易再动员，从叶片到粮食。无机砷的茎转运可能不仅仅依赖于谷氨酸转运蛋白。
Strategies to reduce arsenic in rice grain, below levels that represent a serious human health concern, require that the mechanisms of arsenic accumulation within grain be established. Therefore, re-translocation of arsenic species from flag leaves into filling rice grain was investigated. Arsenic species were delivered through cut flag leaves during grain fill. Spatial unloading within grains was investigated using synchrotron X-ray fluorescence (SXRF) microtomography. Additionally, the effect of germanic acid (a silicic acid analogue) on grain arsenic accumulation in arsenite treated panicles was examined. Dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA) were extremely efficiently re-translocated from flag leaves to rice grain; arsenate was poorly re-translocated, and was rapidly reduced to arsenite within flag leaves; arsenite displayed no re-translocation. Within grains, DMA rapidly dispersed while MMA and inorganic arsenic remained close to the entry point. Germanic acid addition did not affect grain arsenic in arsenite treated panicles. 3D SXRF microtomography gave further information on arsenite localization in the ovular vascular trace (OVT) of rice grains. These results demonstrate that inorganic arsenic is poorly re-mobilized, while organic species are readily re-mobilized, from leaves to grain. Stem translocation of inorganic arsenic may not rely solely on silicic acid transporters.
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影响因子：
11.4
作者：
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通讯作者：
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11.4
作者：
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通讯作者：
Meharg, Andrew A.