采用温室水稻盆栽试验研究2种土壤上水稻铅的生物有效性及土壤铅形态的变化。结果表明:铅对2种土壤水稻干物重和籽粒重量的影响表现为,随铅处理浓度升高,水稻干物重和籽粒重量明显下降。黄红壤上种植的水稻干物重和籽粒重量高于青紫泥。不同铅处理下水稻各器官铅含量表现为根〉茎〉叶〉壳〉籽粒。2种土壤上NH4OAc提取的有效态铅含量与外源铅的量呈显著正相关。随外源土壤铅含量增加土壤pH显著下降。随土壤铅含量增加土壤铅的生物有效性增强,水稻对铅的吸收明显增加,水稻可食部的铅含量升高。采用连续提取法分析了土壤铅的形态,结果表明,青紫泥铁锰氧化态和有机态的铅含量高于黄红壤,水溶态、交换态和碳酸盐态含量低于黄红壤。铅在黄红壤上的移动性较青紫泥高。
The bioavalibility of lead in rice and fractionation of lead in two soils were studied with the pot experiments.The results showed that the increased Pb loading(0~1 200 mg/kg) in two paddy soils had variable effects on plant dry biomass,and Pb concentration in rice plants.Plant dry biomass was higher in Ultisol than Inceptisol,and grain yield in both soils decreased with increasing Pb loadings.The concentrations of Pb in root,leaf,stalk,and grain of rice increased significantly with increasing levels of Pb in both soils,and this increase was more pronounced in Ultisol than Inceptisol.Lead accumulated mainly in the roots and the increase in Pb concentrations due to external Pb input for different plant parts was in the order of root stalk leaf grain.NH4OAc extractable Pb was positively with the Pb concentration of both soils.With increasing loading of Pb decreased soil pH.With increasing loading of Pb could contribute to increasing Pb bioavailabilyty in soil and that could increase Pb uptake and accumulation in the edible parts of rice.By means of fractionation of lead in soil analyed by sequential extraction,the results indicated Fe/Mn oxides and residual fractions in Inceptisol higher than in Ultisol,but water-soluble,exchangeable and carbonate fractions were lower in Inceptisol than in Ultisol.Lead was more mobile in Ultisol than in the Inceptisol soil.