We present a case study on the tissue absorption of copper of a widely distributed moss species, Ptychostomum capillare in the polluted soil of an abandoned copper mine in central Spain. We studied the soil properties in a copper soil pollution gradient and sampled the moss tufts growing on them in four plots with contrasted soil copper levels. We determined the copper content in the soil and in the moss tissues. On these moss samples, we also performed histochemical tests and X-ray dispersive spectrometry coupled with scanning electron microscopy (SEM-EDX), both in untreated shoots and in samples where surface waxes were removed. We checked the behavior of this species using a metallophillous moss, Scopelophila cataractae, for comparative purposes. Copper contents in P. capillare seem to depend more on available, rather than total soil copper contents. Our results indicate that this moss is able to concentrate 12-fold the available soil copper in soil with low available copper content, whereas in the most polluted soil the concentration of Cu in the moss was only half those levels. Both histochemical and SEM-EDX tests show no surface copper in the mosses from the least polluted plot, whereas in samples from the soil with highest copper content, the removal of surface waxes also reduces or removes copper from the moss shoots. Our observations point at a mixed strategy in P. capillare in this copper mine, with metal accumulation behavior in the lowest Cu plot, and an exclusion mechanism involving wax-like substances acting as a barrier in the most polluted plots. These distortions impede the estimation of environmental levels and thus compromise the value of this moss in biomonitoring. We highlight the need of extending these studies to other moss species, especially those used in biomonitoring programs.

中文翻译：

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陆生苔藓鼠毛中的铜含量及其抗性机理：以西班牙中部一个废弃的铜矿为例。

我们提供了一个案例研究，研究了西班牙中部一个废弃铜矿的受污染土壤中分布广泛的苔藓种毛霉菌（Ptychostomum capillare）对铜的组织吸收。我们研究了铜污染土壤梯度中的土壤特性，并在四个土壤铜含量对比的样地中采样了生长在它们上的苔藓簇。我们确定了土壤和苔藓组织中的铜含量。在这些未经处理的芽和去除了表面蜡的样品中，我们还对这些苔藓样品进行了组织化学测试和X射线色散光谱分析以及扫描电子显微镜（SEM-EDX）。为了进行比较，我们使用金属生苔藓（Scopelophila cataractae）检查了该物种的行为。毛果假单胞菌中的铜含量似乎更多地取决于可用量，而不是土壤中的总铜含量。我们的结果表明，这种苔藓能够将可用铜含量低的土壤中的可用土壤铜浓缩12倍，而在污染最严重的土壤中，苔藓中的Cu浓度仅为这些水平的一半。组织化学和SEM-EDX测试均显示污染最小的地段的苔藓中没有表面铜，而在铜含量最高的土壤样品中，表面蜡的去除也可减少或去除苔藓芽中的铜。我们的观察结果指出，在该铜矿中，毛状假单胞菌采取了混合策略，在最低的Cu地段具有金属积累行为，而在污染最严重的地块中，包含蜡状物质的隔离机制成为障碍。这些扭曲妨碍了对环境水平的估计，因此损害了这种苔藓在生物监测中的价值。我们强调需要将这些研究扩展到其他苔藓物种，尤其是用于生物监测计划的物种。