Dependence of Rice Grain Cadmium and Arsenic Concentrations on Environment and Genotype

Rice is a major staple food in China where farmland soil has widespread cadmium (Cd) and arsenic (As) contamination. To provide appropriate rice cultivars to guide rice production in Cd and As co-contaminated paddy soils, the factors affecting Cd and As concentrations in rice require clarification. A pot experiment was conducted to investigate Cd and As translocation and accumulation in different tissues of rice cultivars for understanding the Cd and As variations in rice. Field tests were performed in two seasons to investigate the cultivar, environment, and their interactions in effecting the Cd and As concentrations in rice grains. Wide ranges of Cd and As concentrations in root, stem, leaves, and grains were observed among the rice cultivars. Mean Cd concentrations in grains were higher than that of As, which was due to the higher translocation factors (TFs) of Cd from stems to grains and from leaf to grains than those of As. Multivariate analysis demonstrated that the grain Cd concentration was more susceptible to cultivars, which contributed 32.4% of the variation in the grain Cd concentration. The As concentration in grain was more susceptible to the environment, which contributed 59.9% of the variation in the grain As concentration.