Terzano Roberto, Al Chami Ziad, Vekemans Bart, Janssens Koen, Miano Teodoro, Ruggiero Pacifico
Dipartimento di Biologia e Chimica Agro-forestale ed Ambientale, University of Bari, Via Amendola 165/A, I-70126 Bari, Italy.
J Agric Food Chem. 2008 May 14;56(9):3222-31. doi: 10.1021/jf073304e. Epub 2008 Apr 15.
Zinc distribution and speciation within different organs (root, petiole, and leaf) of the edible plant Eruca vesicaria L. Cavalieri were determined using synchrotron microbeam X-ray techniques (XRF microtomography and mu-XANES) for plants grown in polluted soil with or without compost amendment. Data on soil derived from different extraction procedures and using mu-XANES analyses on rhizospheric soil indicated that compost amendment did not significantly influence the Zn speciation and availability in soil. However, major differences were observed within the plants. Plants grown in the presence of compost were able to partly block zinc immediately outside the root endodermis in the form of zinc-phytate, while a smaller Zn fraction was allowed to xylem transport as zinc-citrate. In the leaves, zinc was largely excluded from leaf cells, and about approximately 50% was in the form of phosphate precipitates, and the other 50% was complexed by cysteine and histidine residues. The reported data provide new information concerning the mechanisms of zinc tolerance in E. vesicaria L. Cavalieri, a very common edible plant in Mediterranean regions, and on the role of compost in influencing the molecular strategies involved in zinc uptake and detoxification.
采用同步辐射微束X射线技术（X射线荧光显微断层扫描和μ-X射线吸收近边结构），对生长在添加或未添加堆肥改良剂的污染土壤中的可食用植物芝麻菜（Eruca vesicaria L. Cavalieri）不同器官（根、叶柄和叶片）内的锌分布和形态进行了测定。来自不同提取程序的土壤数据以及对根际土壤进行的μ-X射线吸收近边结构分析表明，堆肥改良并未显著影响土壤中锌的形态和有效性。然而，在植物内部观察到了主要差异。在有堆肥的情况下生长的植物能够以植酸锌的形式在根内皮层外立即部分阻止锌进入，而较小部分的锌以柠檬酸锌的形式被允许进行木质部运输。在叶片中，锌大部分被排除在叶细胞之外，约50%以磷酸盐沉淀的形式存在，另外50%与半胱氨酸和组氨酸残基络合。所报告的数据提供了关于地中海地区非常常见的可食用植物芝麻菜中锌耐受机制的新信息，以及堆肥在影响锌吸收和解毒所涉及的分子策略中的作用。
