Fractionations of rare earth elements(REEs)and their mechanisms in soybean were studied through application of exogenous mixed REEs under hydroponic conditions.Significant enrichment of middle REEs(MREEs)and heavy REE...Fractionations of rare earth elements(REEs)and their mechanisms in soybean were studied through application of exogenous mixed REEs under hydroponic conditions.Significant enrichment of middle REEs(MREEs)and heavy REEs(HREEs)was observed in plant roots and leaves respectively,with slight fractionation between light REEs(LREEs)and HREEs in stems.Moreover,the tetrad effect was observed in these organs.Investigations into REE speciation in roots and in the xylem sap using X-ray absorption spectroscopy(XAS)and nanometer-sized TiO2 adsorption techniques,associated with other controlled experiments,demonstrated that REE fractionations should be dominated by fixation mechanism in roots caused by cell wall absorption and phosphate precipitation,and by the combined effects of fixation mechanism and transport mechanism in aboveground parts caused by solution complexation by intrinsic organic ligands.A conceptive model was established for REE fractionations in plants based on the above studies.展开更多
基金the Key Project of the National Natural Science Foundation of China(Grant Nos.40571146 and 20577053)
文摘Fractionations of rare earth elements(REEs)and their mechanisms in soybean were studied through application of exogenous mixed REEs under hydroponic conditions.Significant enrichment of middle REEs(MREEs)and heavy REEs(HREEs)was observed in plant roots and leaves respectively,with slight fractionation between light REEs(LREEs)and HREEs in stems.Moreover,the tetrad effect was observed in these organs.Investigations into REE speciation in roots and in the xylem sap using X-ray absorption spectroscopy(XAS)and nanometer-sized TiO2 adsorption techniques,associated with other controlled experiments,demonstrated that REE fractionations should be dominated by fixation mechanism in roots caused by cell wall absorption and phosphate precipitation,and by the combined effects of fixation mechanism and transport mechanism in aboveground parts caused by solution complexation by intrinsic organic ligands.A conceptive model was established for REE fractionations in plants based on the above studies.
