Department of Environmental Science, University of Siena, via P.A. Mattioli 4, 53100 Siena, Italy.
Planta. 2011 Feb;233(2):333-42. doi: 10.1007/s00425-010-1300-0. Epub 2010 Oct 30.
This study aimed to deepen the knowledge about intraspecific mechanisms regulating nitrogen tolerance in lichens to wet nitrogen deposition. Thalli of the nitrophilous lichen Xanthoria parietina were collected from environments with different nitrogen availabilities and immersed in 80 mL of ammonium sulphate (NH₄)₂SO₄ solutions with distinct concentrations (0, 0.025, 0.05 and 0.25 M) for 5 h per day during 3 days in a week. After each soaking event, lichens were air dried. After each treatment, maximal PSII efficiency, localization of ammonium ions, concentrations of K+ and Mg²+ and thalli buffer capacity were determined. Our results show that lichens are marked by their native nitrogen environment, since there were important differences between the physiological responses of X. parietina thalli previously grown in an area with high nitrogen deposition (nitrogen emissions of ca. 13,000 t/year) and those previously grown in an unpolluted area (nitrogen emissions of ca. 500 t/year). Greater N availability seems to enable X. parietina to cope better with the effects of nitrogen pollution.
本研究旨在深入了解调控地衣对湿态氮沉降氮耐受性的种内机制。从氮有效性不同的环境中采集喜氮地衣条斑矶松的藻体，每天在一周内的 3 天中，将藻体浸入 80 mL 不同浓度（0、0.025、0.05 和 0.25 M）的硫酸铵（NH₄）₂SO₄溶液中 5 小时。每次浸泡后，地衣都要风干。每次处理后，测定最大 PSII 效率、铵离子定位、K+和 Mg²+浓度以及藻体缓冲能力。我们的结果表明，地衣因其原生氮环境而具有特征，因为先前在高氮沉降（约 13,000 吨/年的氮排放量）地区生长的条斑矶松藻体与先前在未受污染地区（约 500 吨/年的氮排放量）生长的藻体的生理反应存在重要差异。较高的 N 可用性似乎使 X. parietina 能够更好地应对氮污染的影响。
