Antimony accumulation and iron plaque formation at different growth stages of rice (Oryza sativa L.)

To better understand the Sb phytoavailability in rice, we studied Sb accumulation in rice (Zhongjiazao-17, widely cultivated in Hunan province) at different growth stages based on adding Sb-III and Sb-V to waterlogged soils in 10, 50 and 100 mg kg(-1) treatment levels. Proportional exogenous Sb-III and Sb-V remained in the soil solution after equilibration. In Sb-III treatments, the iron plaque (IP) amounts and Sb in rice roots sharply increased from tillering to jointing stages and then reduced at the following stages. However, in Sb-V treatments, they increased continuously from tillering to maturing stages. The accumulation trends of Sb in straws, ears and grains were consistent in Sb-III and Sb-V treatments, rising from tillering to jointing stages followed with reducing from jointing to flowering stages slightly, and rising again significantly from flowering to maturing stages. The Tfsoil-grain values in all the Sb treatments were low (0.77 x 10(-3)-5.1 x 10(-3)), However, when Sb in waterlogged soils were higher than 50 mg kg(-1), it could pose human health risk for residents. (C) 2019 Elsevier Ltd. All rights reserved.