DISTEM, University of Palermo, Via Archirafi, 22-90123 Palermo, Italy.
SAF Department, University of Palermo, Viale delle Scienze, 13-90128 Palermo, Italy.
Sci Total Environ. 2014 Mar 1;473-474:597-608. doi: 10.1016/j.scitotenv.2013.12.073. Epub 2014 Jan 4.
The geochemical behaviour of lanthanides and yttrium (Rare Earth Elements, REEs) has been investigated mainly in geological systems where these elements represent the best proxies of processes involving the occurrence of an interface between different media. This behaviour is assessed according to features recorded in sequences of REE concentrations along the REE series normalised with respect to a reference material. In this study, the geochemical behaviour of REE was investigated in different parts of Vitis vinifera specimens grown off-soil, on soils of different nature and grafted onto several rootstocks in order to evaluate effects induced by these changes. The results indicated that roots are the plant organs where REEs are preferentially concentrated, in particular elements from Sm to Ho (middle REE, MREE) whereas Eu enrichments occur in aerial parts. The geochemical behaviour of REE suggests that MREE enrichments in roots are due to preferential MREE interactions with biological membranes or to surface complexation with newly formed phosphates. Eu-positive anomalies suggest that Eu(3+) can form stable organic complexes in place of Ca(2+) in several biological processes in xylem fluids. The possibility that Eu mobility in these fluids can be enhanced by its reductive speciation as Eu(2+) cannot be ruled out. The assessment of the geochemical behaviour of REE according to the theory of the Tetrad Effect carried out confirms that REEs coming from soil are scavenged onto root tissues or mineral surfaces whereas their behaviour in aerial parts of V. vinifera is driven by dissolved complexation.
镧系元素和钇(稀土元素,REEs)的地球化学行为主要在地质系统中进行研究,在这些系统中,这些元素是涉及不同介质之间发生界面过程的最佳示踪剂。根据相对于参考物质标准化的 REE 系列中 REE 浓度序列中记录的特征来评估这种行为。在这项研究中,研究了在不同部分的非土壤生长的葡萄藤标本中 REE 的地球化学行为,这些标本生长在不同性质的土壤上,并嫁接到几种砧木上,以评估这些变化引起的影响。结果表明,根是 REE 优先浓缩的植物器官,特别是 Sm 到 Ho(中稀土,MREE)的元素,而 Eu 则在空气中富集。REE 的地球化学行为表明,根中 MREE 的富集是由于 MREE 与生物膜的优先相互作用,或者是与新形成的磷酸盐的表面络合。Eu 正异常表明,Eu(3+)可以在木质部液流中的几个生物过程中形成稳定的有机配合物,取代 Ca(2+)。不能排除 Eu 在这些流体中可以通过其还原态物质 Eu(2+)的形式增强其迁移性的可能性。根据四分组效应理论对 REE 地球化学行为的评估证实,来自土壤的 REE 被清除到根组织或矿物表面上,而 V.vinifera 的空气中部分的行为则由溶解络合驱动。