期刊
PLANT AND SOIL
卷 376, 期 1-2, 页码 423-431出版社
SPRINGER
DOI: 10.1007/s11104-013-1991-7
关键词
Arsenic; Arsenic speciation; Arsenite; Methylated As; Rice; Silicon
资金
- Natural Science Foundation of China [41330853, 41073074]
- Innovative Research Team Development Plan of the Ministry of Education of China [IRT1256]
- Rothamsted International fellowship
- UK Biotechnology and Biological Sciences Research Council
- BBSRC [BBS/E/C/00005197, BBS/E/C/00005206] Funding Source: UKRI
Rice (Oryza sativa) is a main source of human exposure to inorganic arsenic and mitigation measures are needed to decrease As accumulation in this staple crop. It has been shown that silicon decreases the accumulation of arsenite but, unexpectedly, increases the accumulation of dimethylarsinic acid (DMA) in rice grain. The aim of this study was to investigate why Si increases DMA accumulation. Pot and incubation experiments were conducted to investigate how the addition of sparingly soluble silicate gel affected As speciation in the soil solution and the accumulation of different As species in rice tissues. Silicon addition significantly decreased the concentration of inorganic As (mainly arsenite) but increased the concentration of DMA in both the vegetative and reproductive tissues of rice. Silicon increased the concentration of DMA in the soil solution, whereas autoclaving soil decreased DMA concentration. Less DMA was adsorbed by the soil than arsenate and Si addition significantly inhibited DMA adsorption. Silicon increased DMA accumulation and decreased arsenite accumulation in rice through different mechanisms. Silicic acid released from the silicate gel increased the availability of DMA for rice uptake by inhibiting DMA adsorption on the soil solid phase or by displacing adsorbed DMA. Although silicic acid also increased the concentration of inorganic As in the soil solution, this effect was much smaller than the inhibitory effect of Si on arsenite uptake by rice roots.
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