Vieira Ana Rute, Gonzalez Carla, Martins-Loução Maria Amélia, Branquinho Cristina
Faculty of Sciences, Centre for Environmental Biology (CBA), University of Lisbon, Campo Grande, Bloco C2, Piso 5, sala 2.5.37, 1749-016, Lisbon, Portugal.
Ecotoxicology. 2009 Nov;18(8):1087-94. doi: 10.1007/s10646-009-0374-6. Epub 2009 Jul 16.
The objective of this work is to validate the use of the aquatic moss Fontinalis antipyretica as biomonitor of NH(4)(+) aquatic pollution. In order to achieve this objective we needed to understand the pattern of uptake of NH(4)(+) by the moss and evaluate the impact of high concentrations on its physiological performance. The cellular location of NH(4)(+) in the moss is crucial for understanding its monitoring capacity. We were able to show that a sequential elution technique, based on the use of NiCl(2) as an efficient displacing agent, allowed the quantification of the cellular location of NH(4)(+). This was done along a concentration gradient and time of exposure. The extracellular and intracellular NH(4)(+) concentrations that caused significant physiological impact in membrane permeability of F. antipyretica were the same that caused significant decreasing in the photosynthetic capacity of the same moss. The former NH(4)(+) concentration thresholds were shown to decrease with increasing exposure time. These results are important since under natural conditions lower concentration of NH(4)(+) are present in waters but for very long periods of time. The importance of applying this knowledge in biomonitoring studies to fulfil the requirements of the Water Framework Directive is discussed.
这项工作的目的是验证水生苔藓柔枝水藓作为铵（NH₄⁺）水污染生物监测器的用途。为了实现这一目标，我们需要了解苔藓对铵的吸收模式，并评估高浓度铵对其生理性能的影响。苔藓中铵的细胞定位对于理解其监测能力至关重要。我们能够证明，基于使用氯化镍（NiCl₂）作为有效置换剂的连续洗脱技术，可以对铵的细胞定位进行定量。这是沿着浓度梯度和暴露时间进行的。在柔枝水藓膜通透性方面引起显著生理影响的细胞外和细胞内铵浓度，与在同一苔藓光合能力方面引起显著下降的浓度相同。前者的铵浓度阈值显示随着暴露时间的增加而降低。这些结果很重要，因为在自然条件下，水中存在的铵浓度较低，但持续时间很长。本文讨论了将这些知识应用于生物监测研究以满足《水框架指令》要求的重要性。
