Effect of the Air Pollutant Sulfur Dioxide on Phytohormone Levels in Some Lichens

Abstract

In the present study the effect of sulfur dioxide pollution on phytohormonal levels and morphological changes in lichens was investigated. Fumigated sulfur dioxide was applied to Dermatocarpon intestiniforme (Korber) Hasse, Flavoparmelia caperata (L.) Hale, Lecanora muralis (Schreber) Rabenh., Neofuscelia pulla (Ach.) Essl., Rhizocarpon geographicum (L.) DC., Rhizoplaca melanophythalma (DC.) Leuck.& Poelt, Tephromela atra (Huds.) Hafellner, and Xanthophoria elegans (Link.) Th. Fr. in a glass chamber. Dermatocarpon intestinifiorma and Leconara muralis were found to be the most tolerant species. Significant changes in giberellic acid (GA(3))-equivalents, indole-3-acetic acid (IAA), trans-zeatin (t-Z) and abscisic acid (ABA) levels and morphological degeneration were found in most of the lichen species compared to control samples, but also cholorosis, necrosis, detachment from the substrate and chlorophyll breakdown could be observed. ABA levels increased in all lichen species from approx. 1/3 to 8-fold, whereas zeatin levels decreased between 21% and 76%. Elevated levels of GA(3)-equivalents were found in Dermatocarpon intestiniforme, Neofuscelia pulla and Leconara muralis. However, the level of GA(3)-equivalents decreased between 15% and 45% in the others. The levels of IAA were found to be 35% higher in Leconara muralis. A significant change was not determined in Dermatocarpon intestiniforme, whereas IAA values decreased from 16% to 89% in the other species examined.