Mitigation of Arsenic Accumulation in Rice with Water Management and Silicon Fertilization
Mitigation of Arsenic Accumulation in Rice with Water Management and Silicon Fertilization
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DOI：
10.1021/es803643v
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发表时间：
2009-05-15
影响因子：
11.4
通讯作者：
Zhao, F. J.
中科院分区：
文献类型：
--
作者：
Li, R. Y.;Stroud, J. L.;Zhao, F. J.
在依赖大米饮食的人群中，大米是接触砷的主要途径。需要采取切实的措施来缓解水稻中砷的过量积累问题。在温室条件下，研究了两种可能的缓解措施：水分管理和硅肥。在水稻整个生育期内进行有氧种植，导致了至少砷的积累。在水稻营养生长期或生殖生长期维持有氧条件也减少了稻草和籽粒中的积累量，与淹水条件下的水稻相比，稻草和籽粒中的积累量显着减少。水分管理措施的效果与观察到的淹水诱导土壤溶液中亚砷酸盐活化的效果是一致的。旱作提高了水稻籽粒中无机砷的含量，但无机砷的浓度仍低于淹水水稻。施硅使秸秆和籽粒中的总砷浓度分别降低了78%和16%，而施硅量则增加了土壤溶液中总砷的浓度。硅还通过促进甲基化显著影响稻谷和稻壳中的形态形成。硅使谷物中无机砷的浓度降低了59%，而二甲基砷酸(DMA)的浓度增加了33%。两个水稻品种在籽粒形态上也存在显著差异。本研究表明，水分管理、施硅肥和选择水稻品种是减少As在水稻体内积累的有效措施。
Rice represents a major route of As exposure in populations that depend on a rice diet. Practical measures are needed to mitigate the problem of excessive As accumulation in paddy rice. Two potential mitigation methods, management of the water regime and Si fertilization, were investigated under greenhouse conditions. Growing rice aerobically during the entire rice growth duration resulted in the leastAS accumulation. Maintaining aerobic conditions during either vegetative or reproductive stage of rice growth also decreased As accumulation in rice straw and grain significantly compared with rice grown under flooded conditions. The effect of water management regimes was consistent with the observed effect of flooding-induced arsenite mobilization in the soil solution. Aerobic treatments increased the percentage of inorganic As in grain, but the concentrations of inorganic As remained lower than in the flooded rice. Silicon fertilization decreased the total As concentration in straw and grain by 78 and 16%, respectively, even though Si addition increased As concentration in the soil solution. Silicon also significantly influenced As speciation in rice grain and husk by enhancing methylation. Silicon decreased the inorganic As concentration in grain by 59% while increasing the concentration of dimethylarsinic acid (DMA) by 33%. There were also significant differences between two rice genotypes in grain As speciation. This study demonstrated that water management, Si fertilization, and selection of rice cultivars are effective measures that can be used to reduce As accumulation in rice.