Localized flux maxima of arsenic, lead, and iron around root apices in flooded lowland rice.
Localized flux maxima of arsenic, lead, and iron around root apices in flooded lowland rice.
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DOI：
10.1021/es501127k
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发表时间：
2014
影响因子：
11.4
通讯作者：
Zhang, Hao
中科院分区：
文献类型：
--
作者：
Williams, Paul N.;Santner, Jakob;Larsen, Morten;Lehto, Niklas J.;Oburger, Eva;Wenzel, Walter;Glud, Ronnie N.;Davison, William;Zhang, Hao
在水稻等适应湿地的植物中，根尖通常是水/养分快速进入的部位，径向氧损失 (ROL) 最高。因此，营养/有毒金属的吸收主要通过氧化区和 pH 微梯度发生。然而，由于缺乏同时测量不稳定微量元素和 O2/pH 的技术，控制水稻中微量元素获取的过程一直难以通过实验探索。在这里，我们在水稻根部原位部署的薄膜 (DGT)/平面光极夹层传感器中使用新的扩散梯度，以证明一种新的地球化学生态位，该生态位大大增强了 As、Pb 和 Fe(II) 迁移到紧邻根尖的溶液中的能力，其特点是富氧和低 pH。 Fe(II) 动员与好氧根区外围边缘的动员一致，表明当氧化前沿穿透还原性土壤时，Fe(II) 动员最大值仅在狭窄的 O2 范围内出现。根尖处 DGT 树脂的 Fe 通量比厌氧土块高 3 倍，比需氧生根区高 27 倍。这些结果为铁的耦合扩散和氧化在调节痕量金属溶解、分散和植物吸收中的重要性提供了新的证据。
In wetland-adapted plants, such as rice, it is typically root apexes, sites of rapid entry for water/nutrients, where radial oxygen losses (ROLs) are highest. Nutrient/toxic metal uptake therefore largely occurs through oxidized zones and pH microgradients. However, the processes controlling the acquisition of trace elements in rice have been difficult to explore experimentally because of a lack of techniques for simultaneously measuring labile trace elements and O2/pH. Here, we use new diffusive gradients in thin films (DGT)/planar optode sandwich sensors deployed in situ on rice roots to demonstrate a new geochemical niche of greatly enhanced As, Pb, and Fe(II) mobilization into solution immediately adjacent to the root tips characterized by O2 enrichment and low pH. Fe(II) mobilization was congruent to that of the peripheral edge of the aerobic root zone, demonstrating that the Fe(II) mobilization maximum only developed in a narrow O2 range as the oxidation front penetrates the reducing soil. The Fe flux to the DGT resin at the root apexes was 3-fold higher than the anaerobic bulk soil and 27 times greater than the aerobic rooting zone. These results provide new evidence for the importance of coupled diffusion and oxidation of Fe in modulating trace metal solubilization, dispersion, and plant uptake.
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影响因子：
2.3
作者：
Fones, GR;Davison, W;Hamilton-Taylor, J
通讯作者：
Hamilton-Taylor, J
影响因子：
4
作者：
Christensen, KK;Jensen, HS;Holmer, M
通讯作者：
Holmer, M
影响因子：
4.5
作者：
Frederiksen, MS;Glud, RN
通讯作者：
Glud, RN
影响因子：
2.7
作者：
Larsen, Morten;Borisov, Sergey M.;Glud, Ronnie N.
通讯作者：
Glud, Ronnie N.
影响因子：
4.2
作者：
Batty, LC;Baker, AJM;Curtis, CD
通讯作者：
Curtis, CD