农用稀土对大田玉米中稀土元素分布的影响

以潮土为例，采用田间试验方法，研究了农用稀土施加后不同时期大田玉米体内16种稀土含量的变化。结果表明，所施稀土很快地被玉米根系吸收并运移到地上部分。根系中稀土含量存在显著的剂量-效应关系。并不随玉米生育期而发生明显变化，但玉米生长可显著影响到地上部分稀土的分布，尤其在低剂量稀土作用时。稀土肥料施用后玉米体内单一稀土含量依根系≥叶〉茎〉籽实的顺序减少；玉米体内La的吸收和运移明显快于Ce和Sm，并随生育期而发生变化；土壤中Gd较容易被玉米根系吸收并转移到地上部分。在此实验条件下，农用稀土施加后玉米体内单一稀土的吸收和运移具有选择性，随玉米生育期而发生变化；根系中单一稀土限口La、Ce和Sm）的选择性积累可能存在一种动态平衡。

Distributions of Rare Earth Elements in Field-Grown Maize After Application of Rare Earth-Containing Fertilizer

The distribution of 16 rare earth elements(Sc,Y and 14 lanthanide elements)in field-grown maize during different stages was studied upon addition of rare earth-containing fertilizer to a luvisol soil.It was found that the translocation of individual rare earth was rapid from maize roots to plant tops.There was a significant dose-dependent relation of the accumulation of individual rare earth in roots,and it was not variable with growth of maize.However,the maize growth can significantly affect the distribution of individual rare earth in the plant tops,particularly at low dosages of rare earths.Concentrations of individual rare earth in the plant decreased in an order of roots leaf stem grain.The accumulation and transport of lanthanum in maize was apparently greater than that of Ce and Sm,and it varied with the maize growth.Gd in the soil was easily taken up by maize roots and transferred from roots to plant tops.Under experimental conditions,selective accumulation and translocation of individual rare earth(e.g.La,Ce,Sm)were thus present in maize and it varied with maize growth.It was found that the accumulation in the roots seemed to be in dynamic equilibrium.