Comparative Analysis of Morphophysiological Responses of the Lichen Parmelia sulcata and the Moss Orthotrichum speciosum to Simulated Acidic and Ammonium Air Pollution

This study presents the results of a model experiment investigating the effects of atmospheric pollutants – sulfuric and nitric acids, ammonium sulfate, and ammonium nitrate – on the epiphytic organisms Parmelia sulcata and Orthotrichum speciosum. The experiment simulated the deposition of polluted atmospheric precipitation. The assessment included spectrophotometric analysis of photosynthetic pigment content (chlorophylls a and b) and evaluation of morphological changes. All tested pollutants induced stress responses manifested by reduced pigment content and structural tissue damage. Ammonium sulfate ((NH4)2SO4) exerted the most pronounced inhibitory effect, leading to sharp pigment decline and morphological degradation. In contrast, ammonium nitrate (NH4NO3) had the least damaging effect, likely due to its high bioavailability and balanced nitrogen composition. The lichen P. sulcata exhibited more pronounced changes and higher sensitivity, while the moss O. speciosum showed signs of resistance and compensatory reactions. Cluster analysis confirmed differences between the taxa and revealed two stable response types: sensitive (P. sulcata) and compensatory (O. speciosum). The findings highlight the diagnostic value of a comprehensive approach combining biochemical and morphological indicators for assessing the state of the atmospheric environment within ecological monitoring frameworks.