Abstract:

Single extraction procedures with low molecular weight organic acids (LMWOAs), sodium salts of LMWOAs, DTPA, EDTA, CaCl2 and NaNO3 as extracts were performed to extract light rare earth elements La, Ce, Pr and Nd from plant root wet rhizhosphere soil. The bioavailability of light rare earth elements from maize root is evaluated by single regression analysis. The results showed that light rare earth elements adsorbed by plant root cell wall and taken up by cross-membrane were utilizable, and the total content of rare earth elements in plant root can be used for predicting bioavailability. For the prediction of bioavailability of light rare earth elements in maize root and leaves, different extracts had different effects. LMWOAs, sodium salts of LMWOAs and DTPA were quite good extracts for predicting bioavailability of light rare earth elements uptake by maize root（significant at 0.10 probability level at least）. Neutral salts CaCl2 and NaNO3 were also good extracts for predicting bioavailability of light rare earth elements uptake by maize leaf   significant at 0.10 probability level at least）. In contrast, the correlation coefficients with maize root or leaf were poor when EDTA was used as extract.

Key words: light rare earth elements, bioavailability, extraction, single regression

摘要：

采用低分子量有机酸及其钠盐、CaCl2、NaNO3、DTPA和EDTA作为萃取剂,用一步提取法萃取植物根际湿土壤,测定了萃取液中轻稀土元素La、Ce、Pr和Nd的浓度。用一元回归分析法评价了使用不同萃取剂时轻稀土元素的生物可利用性。结果表明,玉米根细胞壁吸附和跨膜吸收的轻稀土元素都是植物可以吸收利用的,可以用根中总稀土元素来预测生物可利用性。对于预测玉米根和叶中轻稀土元素的生物可利用性,不同的萃取剂有不同的效果：低分子量有机酸及其钠盐以及DTPA萃取的轻稀土元素与玉米根中的相应元素有较好的相关关系（至少在0.10水平下显著相关）,可以较好地预测玉米对轻稀土元素的吸收,中性盐类萃取剂CaCl2和NaNO3萃取的轻稀土元素和玉米叶中的相应元素有较好的相关关系（至少在0.10水平下显著相关）,而EDTA萃取的轻稀土元素与玉米根或叶中的相应元素没有相关关系。

关键词: 轻稀土元素;生物可利用性;萃取;一元回归