Haffner E, Lomsky B, Hynek V, Hallgren JE, Batic F, Pfanz H
Air pollution and lichen physiology. Physiological responses of different lichens in a transplant experiment following an SO2-gradient
Water Air and Soil Pollution: 2001 131:185-201
Four lichen species, Parmelia sulcata Taylor, Hypogymnia physodes (L.) Nyl., Cetraria islandica (L.) Ach., and Bryoria fuscescens (Gyelnik) Brodo and Hawksworth were exposed during autumn and winter at different sites of the Erzgebirge (Ore Mountains), the Fichtelgebirge and control sites. All lichens tested became visibly damaged with time. Thallus bleaching started from the edges and went on to the centre of the thallus. Sites of facilitated gas exchange like the soralia of P. sulcata and the pseudocyphelles of C. islandica became preferentially bleached. The sulfate concentration increased with exposure time reaching 200% of unpolluted controls. In contrast to coniferous trees (e.g. Picea abies), further exposure lead to a reduction in the S-concentration in the lichens, as sulfate and other intracellular metabolites were leached from the thalli due to membrane damage. The changes in the K-concentration proved to be an excellent measure for membrane leakiness, it was correlated with time of exposure and with SO2 concentrations at the different sites. Photosynthetic capacity and respiration were also strongly affected. Depending on the SO2-dose, the Bryoria species were unable to photosynthesize as early as 4-8 weeks after exposure, whereas Cetraria and Hypogymnia showed clear reduction in their ability to photoreduce CO2 within 8-10 weeks of exposure in the field. Parmelia sulcata was found to be the most tolerant species. After 3-4 months, photosynthesis was reduced by only 30%. The bioindicative value of these observations is discussed.
e-link to journal