CIMAR/CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal.
CIMAR/CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal.
Sci Total Environ. 2017 Mar 1;581-582:801-810. doi: 10.1016/j.scitotenv.2017.01.015. Epub 2017 Jan 7.
This study aimed to investigate Cu oxide nanoparticles (CuO NP) effect on microbial communities associated with salt marsh plants (Halimione portulacoides and Pragmites australis) rhizosphere and its implications for phytoremediation processes. Experiments were conducted, under controlled conditions, over one week. Rhizosediment soaked in the respective elutriate (a simplified natural medium) with or without plants, was doped with CuO NP or with Cu in ionic form. Microbial community in rhizosediments was characterized in terms of abundance (by DAPI) and structure (by ARISA). Metal uptake by plants was evaluated by measuring Cu in plant tissues (by atomic absorption spectroscopy). Results revealed significant metal uptake but only in plant roots, which was significantly lower (H. portulacoides) or not significant (P. australis) when the metal was in NP form. Microbial community structure was significantly changed by the treatment (absence/presence of Cu, ionic Cu or CuO NP) as showed by multivariate analysis of ARISA profiles and confirmed by analysis of similarities (Global test - one way ANOSIM). Moreover, in P. australis rhizosediments microbial abundance, bacterial richness and diversity indexes were significantly affected (increased or decreased) due to metal presence whereas in H. portulacoides rhizosediment microbial abundance showed a significant decrease, particularly when the metal was in NP form. Accordingly, Cu presence affected the response of the rhizosphere microbial community and in some cases that response was significantly different when Cu was in NP form. The response of the microbial communities to Cu NP might also contribute to the lower metal accumulation by plants when the metal was in this form. So, Cu NP may cause disturbances in ecosystems functions, ultimately affecting phytoremediation processes. These facts should be considered regarding the use of appropriate salt marshes plants to remediate moderately impacted areas such as estuaries, where NPs can be found.
本研究旨在调查氧化铜纳米颗粒（CuO NP）对盐沼植物（滨藜和互花米草）根际相关微生物群落的影响及其对植物修复过程的意义。在一周的时间里，在控制条件下进行了实验。用或不用植物的各自洗脱液（简化的天然培养基）浸泡根沉积物，并掺杂 CuO NP 或离子形式的 Cu。通过 DAPI 测定丰度（DAPI）和 ARISA 测定结构（ARISA）来描述根沉积物中的微生物群落。通过原子吸收光谱法（atomic absorption spectroscopy）测量植物组织中的 Cu 来评估植物对金属的吸收。结果表明，金属的吸收量显著，但仅在植物根系中，当金属呈 NP 形式时，吸收量显著降低（滨藜）或不显著（互花米草）。多变量分析 ARISA 图谱和相似性分析（单向 ANOSIM 全局检验）表明，处理（有无 Cu、离子 Cu 或 CuO NP）显著改变了微生物群落结构。此外，在互花米草根沉积物中，由于金属的存在，微生物丰度、细菌丰富度和多样性指数显著受到影响（增加或减少），而在滨藜根沉积物中，微生物丰度显著减少，特别是当金属呈 NP 形式时。因此，Cu 的存在影响了根际微生物群落的反应，在某些情况下，当 Cu 呈 NP 形式时，这种反应有显著差异。微生物群落对 Cu NP 的反应也可能导致植物对金属的积累减少，当金属以这种形式存在时。因此，Cu NP 可能会干扰生态系统功能，最终影响植物修复过程。在考虑使用适当的盐沼植物来修复如河口等中度受影响的区域时，应考虑这些因素。
