Research Center for Eco-Environmental Sciences, The Chinese Academy of Sciences, Beijing 100085, China.
Environ Sci Technol. 2010 Sep 1;44(17):6706-11. doi: 10.1021/es101843x.
Selenium, an essential micronutrient for humans, is insufficient in dietary intake for millions of people worldwide. Rice as the most popular staple food in the world is one of the dominant selenium (Se) sources for people. The distribution and translocation of Se from soil to grain were investigated in a Se-rich environment in this study. The Se levels in soils ranged widely from 0.5 to 47.7 mg kg(-1). Selenium concentration in rice bran was 1.94 times higher than that in corresponding polished rice. The total Se concentrations in the rice fractions were in the following order: straw>bran>whole grain>polished rice>husk. Significant linear relationships between different rice fractions were observed with each other, and Se in the soil has a linear relationship with different rice fractions as well. Se concentration in rice can easily be predicted by soil Se concentrations or any rice fractions and vice versa according to their linear relationships. In all rice samples for Se speciation, SeMet was the major Se species, followed by MeSeCys and SeCys. The average percentage for SeMet (82.9%) and MeSeCys (6.2%) was similar in the range of total Se from 2.2 to 8.4 mg kg(-1) tested. The percentage of SeCys decreased from 6.3 to 2.8%, although its concentration elevated with the increase in total Se in rice. This could be due to the fact that SeCys is the precursor for the formation of other organic Se compounds. The information obtained may have considerable significance for assessing translocation and accumulation of Se in plant.
硒是人体必需的微量元素，全世界有数百万人的饮食中摄入不足。大米是世界上最受欢迎的主食之一，是人体硒（Se）的主要来源之一。本研究在富硒环境中研究了 Se 从土壤向谷物的分布和迁移。土壤中的 Se 水平从 0.5 到 47.7mg/kg 不等。米糠中的 Se 浓度比相应的精米高 1.94 倍。稻谷各部位的总 Se 浓度顺序为：稻草>米糠>整粒米>精米>稻壳。不同稻谷部位之间存在显著的线性关系，土壤中的 Se 与不同稻谷部位之间也存在线性关系。根据线性关系，可以通过土壤 Se 浓度或任何稻谷部位很容易预测稻谷中的 Se 浓度，反之亦然。在所有用于 Se 形态分析的稻米样品中，SeMet 是主要的 Se 形态，其次是 MeSeCys 和 SeCys。在测试的总 Se 范围为 2.2 到 8.4mg/kg 时，SeMet（82.9%）和 MeSeCys（6.2%）的平均百分比相似。尽管其浓度随着稻米中总 Se 的增加而升高，但 SeCys 的百分比从 6.3%下降到 2.8%。这可能是因为 SeCys 是形成其他有机 Se 化合物的前体。获得的信息对于评估 Se 在植物中的迁移和积累可能具有重要意义。
