Departamento de Ciências Biológicas, Centro de Microscopia Eletrônica, Universidade Estadual de Santa Cruz, Rodovia Ilhéus-Itabuna km 16, Ilhéus, Bahia, Brazil.
Biometals. 2011 Dec;24(6):1017-26. doi: 10.1007/s10534-011-9459-9. Epub 2011 May 12.
The aim of the present study was to identify the sites of accumulation of Cr in the species of macrophytes that are abundant in the Cachoeira river, namely, Alternanthera philoxeroides, Borreria scabiosoides, Polygonum ferrugineum and Eichhornia crassipes. Plants were grown in nutritive solution supplemented with 0.25 and 50 mg l(-1) of CrCl(3)·6H(2)O. Samples of plant tissues were digested with HNO(3)/HCl in a closed-vessel microwave system and the concentrations of Cr determined using inductively-coupled plasma mass spectrometry (ICP-MS). The ultrastructure of root, stem and leaf tissue was examined using transmission electron microscopy (TEM) and secondary ion mass spectrometry (SIMS) in order to determine the sites of accumulation of Cr and to detect possible alterations in cell organelles induced by the presence of the metal. Chromium accumulated principally in the roots of the four macrophytes (8.6-30 mg kg(-1) dw), with much lower concentrations present in the stems and leaves (3.8-8.6 and 0.01-9.0 mg kg(-1) dw, respectively). Within root tissue, Cr was present mainly in the vacuoles of parenchyma cells and cell walls of xylem and parenchyma. Alterations in the shape of the chloroplasts and nuclei were detected in A. philoxeroides and B. scabiosoides, suggesting a possible application of these aquatic plants as biomarkers from Cr contamination.
本研究的目的是确定 Cr 在丰水河流中丰富的大型水生植物物种中的积累部位，这些物种包括Alternanthera philoxeroides、Borreria scabiosoides、Polygonum ferrugineum 和 Eichhornia crassipes。植物在添加 0.25 和 50 mg l(-1) CrCl(3)·6H(2)O 的营养溶液中生长。用 HNO(3)/HCl 在封闭微波系统中消化植物组织样品，并用电感耦合等离子体质谱仪 (ICP-MS) 测定 Cr 浓度。使用透射电子显微镜 (TEM) 和二次离子质谱 (SIMS) 检查根、茎和叶组织的超微结构，以确定 Cr 的积累部位，并检测金属存在引起的细胞细胞器可能发生的变化。Cr 主要积累在四种大型水生植物的根中（8.6-30 mg kg(-1) dw），茎和叶中的浓度要低得多（3.8-8.6 和 0.01-9.0 mg kg(-1) dw）。在根组织中，Cr 主要存在于薄壁细胞和木质部和薄壁细胞的液泡中。在 A. philoxeroides 和 B. scabiosoides 中检测到叶绿体和细胞核形状的变化，这表明这些水生植物可能作为 Cr 污染的生物标志物。
