Localized flux maxima of arsenic, lead, and iron around root apices in flooded lowland rice

Williams, Paul Nicholas and Santner, Jakob and Larsen, Morten and Lehto, Niklas J. and Oburger, Eva and Wenzel, Walter W. and Glud, Ronnie N. and Davison, William and Zhang, Hao (2014) Localized flux maxima of arsenic, lead, and iron around root apices in flooded lowland rice. Environmental Science and Technology, 48 (15). pp. 8498-8506. ISSN 0013-936X

Full text not available from this repository.

Abstract

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.

Item Type:
Journal Article
Journal or Publication Title:
Environmental Science and Technology
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/2300/2304
Subjects:
?? environmental chemistrygeneral chemistrychemistry(all) ??
ID Code:
81219
Deposited By:
Deposited On:
30 Aug 2016 13:30
Refereed?:
Yes
Published?:
Published
Last Modified:
16 Jul 2024 10:15