Effects of Soil pH Value on the Bioavailability and Fractionation of Rare Earth Elements in Wheat Seedling (Triticum aestivum L.)
土壤酸度对稀土元素在小麦体内的生物可利用性及分馏效应的影响

The effect of soil pH value on the bioavailability and fractionation of rare earth elements (REEs) in wheat seedling ( Triticum aestivum L.) were investigated. The results showed that the concentration of REEs in wheat decreased with increasing pH value, and their inter relationship was best expressed as quadratic equation, with correlation coefficients from 0.6003 to 0.9572. The response of individual elements to pH value change tended to be Ce>La>Nd>Sm> Gd>Yb>Eu, with Ce most sensitive to changing pH conditions and Eu lest. Chemical fractionation indicated that the order of REEs concentration in three fractions could be as follows: B2(NH2OH·HCl extraction)>B3(H2O2 NH4Ac extract)>B1(HAc extract). The increase of pH value resulted in transformation from B1 to B2 and B3. Multiple regression analysis was utilized to obtain the regression equations for prediction plant uptake of REEs. B1 fraction was most available to wheat. Meanwhile, it was found that the fractionation factors of REEs in wheat were negatively correlated with the soil pH value.