Sequestration of As by iron plaque on the roots of three rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.) cultivars in a low-P soil with or without P fertilizer |
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Authors: | Y?Hu J-H?Li Email author" target="_blank">Y-G?ZhuEmail author Y-Z?Huang H-Q?Hu P?Christie |
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Institution: | (1) Research center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China;(2) College of Environmental and Resource Sciences, Huazhong Agricultural University, Wuhan, China;(3) Department of Agricultural and Environmental Science, Queen’s University of Belfast, Newforge Lane, Belfast, BT9 5PX, UK |
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Abstract: | A pot experiment was carried out in a greenhouse to investigate the sequestration of As in iron plaques on root surface of
three rice (Oryza sativa L.) cultivars. Phosphate (P) fertilization increased both plant biomass and tissue P concentrations significantly, indicating
that the soils used in this study was highly P-deficient. Results from this study confirmed that low P supply improved the
formation of iron plaque on rice roots. As a consequence, arsenic (As) concentrations in DCB-extracts with no P addition were
significantly higher than those with P fertilization. Arsenic was highly sequestrated in iron plaque; arsenic concentration
in iron was up to nearly 120 mg kg−1, while arsenic concentrations in roots were just several mg kg−1. Both arsenic and phosphate concentrations in iron plaque were highly positively correlated with the amounts of iron plaque
(DCB-extractable Fe). Contrary to normal understanding that increasing P supply could reduced As accumulation in plants, results
from the present study showed that P fertilization did not inhibit the As uptake by plants (As accumulation in aboveground),
which was probably due to the fact that iron plaque formation was improved under low P conditions, thus leading to more As
sequestration in the iron plaque. Thus results obtained in this study indicated that the iron plaque may inhibit the transfer
of As from roots to shoots, and thus alter the P–As interaction in plant As uptake processes. |
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Keywords: | arsenic iron plaque Oryza sativa rhizosphere sequestration |
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