混合稀土和镧施加后苗期玉米体内稀土元素分布的剂量/效应关系研究

Distributions of Individual Rare Earths in Maize Seedling after Application of Mixed Rare Earths or Lanthanum

以潮土和玉米分别为供试土壤和作物进行盆栽实验。当混合稀土或La与土壤混合后 ,苗期玉米根系和地上部分中稀土元素含量存在明显的剂量 效应关系。施加混合稀土时 ,玉米根系和地上部分中轻稀土和Gd含量分别在 10和 5 0mg·kg- 1 风干土时出现显著性聚集效应 ;在La施用量为 5和 10mg·kg- 1 风干土时 ,玉米根系和地上部分中La含量分别出现显著性聚集效应。施加较大剂量混合稀土或La时 ,玉米根系和地上部分中Gd含量均出现显著性正异常 ;当混合稀土施用量为 5 0mg·kg- 1 时 ,玉米根系和地上部分中均出现显著性Ce负异常现象 ;苗期玉米地上部分和根系La∶Ce和La∶Sm比值均随混合稀土或La施用量增大而呈增加趋势 ;在高剂量稀土 ( >5 0mg·kg- 1 ) ,尤其在La作用时 。

Pot experiments were carried out to study the accumulation of individual rare earths in maize seedling after application of mixed rare earths and lanthanum. After mixed rare earths and La were applied to luvisol , significant dose dependent accumulation of individual rare earths in the roots and the above ground parts of maize seedlings was observed. A significant increase in the concentration of light rare earths and Gd in the roots and the above ground parts appears at the dosages larger than 10 and 50 mg·kg -1 air dried soil, respectively. When La alone is applied, a significant increase in the concentration of La in the roots and the above ground parts appeared at the dosages larger than 5 and 10 mg·kg -1 air dried soil, respectively. Positive Gd anomalies in the roots and the above ground parts of maize were reported, particularly at a large application dosage. When the dosages of the applied rare earths are larger than 50 mg·kg -1 air dried soil, a negative Ce anomaly in maize appears, but this phenomenon can not be observed when La alone is applied. Increasing dosages of the applied rare earths appear larger ratio values of La∶Ce and La∶Sm in any part of maize seedling. When larger than 50 mg·kg -1 air dried soil is applied, the translocation of absorbed La from the roots to the above ground parts can be weakened, particularly in the presence of exogenous lanthanum.