The Role of Selenium in Soil: Effect on the uptake and Translocation of Arsenic in Rice (Oryza sativa L.)

The contamination of paddy soils by arsenic (As) is a serious problem in rice production areas across the world. This study investigates the effect selenium (Se) has on the formation of iron plaques on the outside of rice roots and the accumulation of As in rice plants. A soil combined sand pot experiment having four concentrations of Se (0, 1, 5 and 10 mg kg -1 ) and two concentrations of As (0 and 30 mg kg -1 ) was designed for this investigation. The results indicate that higher concentrations of Se result in a significant decline in As recorded in rice plants. However, the concentration of As in plant roots show the opposite trend. The bio-concentration factor in stems and leaves, as an assessment index of metal accumulation, was 12-51 times greater than that recorded in brown rice, indicating that stems and leaves are the most important tissues for the accumulation of As, and not rice grains. In addition, Se can reduce the bio-concentration factor of As in leaves, stems, rice grains and rice husks, and Se can reduce the translocation factor of As. This mechanism can be ascribed to the higher amounts of Se that decreased the availability of As, increased the number of iron plaques outside the rice roots, and the glutathione concentration in the leaves. The addition of Se also significantly increased the concentration of selenomethionine (SeMet) in rice grains. Therefore, in an As contaminated cropland, fertilizer containing Se can be used to improve the Se nutrition of rice, reduce the accumulation of As in rice grains which are planting in As-contaminated soils, and thus reduce the potential harm of As to human health. © 2017 Friends Science Publishers