title: [Cd uptake and accumulation in grains by hybrid rice in two paddy soils: interactive effect of soil type and cultivars].
abstract: Cd translocation through soil-food crop-diet is considered as one of most important pathway for human Cd exposure. Rice is considered as a particular crop with high Cd uptake and accumulation in grains among the main food crops. In this study, a pot experiment was conducted to elucidate mutual interaction of soil and cultivars on uptake and grain accumulation of Cd by hybrid rice with or without Cd spiking at 2.5 mg x kg(-1) under continuous submerging condition. Two hybrid rice cultivars (Shanyou 63, a common hybrid rice and II Youming 86, a super-rice) and two paddy soils (a Wushantu, Gleyic Stagnic Anthrosols and a Hongshanitian, Ultic Stagnic Anthrosols) were used. The results show significant differences in Cd uptake and grain partitioning between soils, cultivars and the soil-cultivar interactions. The cultivars effect on uptake of indigenous soil Cd seems stronger than the soil effect while soil effect turns significant over that of cultivars on spiked Cd. However, intense Cd accumulation in grains is found under the positive interaction of soil with high Cd availability and cultivar with high Cd affinity (super rice on acidic paddy soil). This study demonstrates a phenomenon of intense Cd uptake and grain accumulation by super rice and, thus, imposing a very high Cd exposure risk (as several times as the acceptable daily intake, ADI) to subsistence-diet farmers. The low Cd cultivar Shanyou 63 tends to hamper the up-taken Cd in root while the super rice II Youming 86 promotes higher partitioning to grain. Furthermore, the difference in total biomass between the two cultivars is small compared to that in total Cd uptake under Cd spiking. It is suggested that the Cd uptake behavior should be taken into account in super rice breeding and practical measures should be taken while spread of super rice cultivars in rice areas with acidic soils and under Cd pollution in order to control the human Cd exposure by diet.
authors.affiliation: Institute of Resources, Ecosystem and Environment of Agriculture, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Wei-Qun
authors.initials: WQ
authors.lastname: Gong
authors.forename: Lian-Qing
authors.initials: LQ
authors.lastname: Li
authors.forename: Gen-Xing
authors.initials: GX
authors.lastname: Pan
mesh_terms: D002104:Cadmium / Q000032:analysis / Q000378:metabolism*; D002523:Edible Grain / Q000378:metabolism; D005506:Food Contamination / Q000032:analysis / Q000517:prevention & control; D006801:Humans; D006824:Hybridization, Genetic; D012275:Oryza / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D012989:Soil Pollutants / Q000032:analysis / Q000378:metabolism*
chemical_list: D012989:Soil Pollutants; D002104:Cadmium