Department of Environmental Science, University of Siena, via Mattioli 4, 53100 Siena, Italy.
Ecotoxicol Environ Saf. 2010 Oct;73(7):1785-8. doi: 10.1016/j.ecoenv.2010.07.042. Epub 2010 Aug 14.
The present work aims at testing if exposure time and dose play a role in the response of lichen species to nitrogen (N) pollution. To this purpose, samples of the N-sensitive Evernia prunastri and the N-tolerant Xanthoria parietina were treated for 5 weeks either with solutions of NH(4)NO(3) 0.05 and 1 M, or (NH(4))(2)SO(4) 0.025 and 0.5 M. Photosynthetic efficiency was measured as an indicator of sample vitality. The results showed that the lowest concentrations were ineffective at the beginning, but after several supplies both compounds inhibited photosynthetic activity of E. prunastri. The highest concentrations had a deleterious effect, but with a temporal trend. For X. parietina no effect was found for the lowest concentrations, while the same trend shown by E. prunastri was instead observed following treatments with the highest concentrations. It was concluded that the response of lichens to N supply is not only species-specific, but also time- and dose-dependent. The results give a clue on field studies on the relationships between lichens and N pollution.
本研究旨在探讨暴露时间和剂量是否会影响地衣物种对氮（N）污染的响应。为此，我们用浓度为 0.05 和 1 M 的 NH(4)NO(3)溶液以及 0.025 和 0.5 M 的(NH(4))(2)SO(4)溶液处理对 N 敏感的长松萝（Evernia prunastri）和对 N 耐受的条斑矶松（Xanthoria parietina）样本 5 周。用光合效率作为样本活力的指标。结果表明，最初低浓度的处理效果不明显，但多次处理后两种化合物均抑制了长松萝的光合作用活性。高浓度处理则表现出有害作用，但存在时间趋势。对于条斑矶松，低浓度处理没有效果，而高浓度处理则表现出与长松萝相同的趋势。结论表明，地衣对 N 供应的响应不仅具有物种特异性，而且还具有时间和剂量依赖性。这些结果为地衣与 N 污染之间关系的野外研究提供了线索。
