Effect of different levels of air pollution on photosynthetic activity of some lichens

Four lichen species: Hypogymnia physodes, Pseudevernia furfuracea, Parmelia saxatilis, and Platismatia glauca were collected from two sites (S. Poland) with a different air pollution level: "Kamienica valley" (less polluted) and "Kopa" (more polluted). The thalli were compared with respect to their: net photosynthetic rate (PN), fluorescence parameters (Fv/Fm, Fm, Fm/Fo), chlorophyll a+b content, and phaeophytinization quotient (O.D.435/O.D.415). PN intensity, chlorophyll a+b and O.D.435/O.D.415 were reduced only in Pa furfuracea collected from Kopa, which is in agreement with the Hawksworth-Rose scale of sensitivity of lichens to air pollution. Fluorescence parameters were significantly lowered in all lichens coming from the more polluted site (except of Fv/Fm and Fm/F0 in P. saxatilis). Parameters based on chlorophyll fluorescence measurements enable to reveal the very early signs of decreased photosynthetical capacity of the thalli, caused by air pollution, before changes in the other photosynthetic parameters become mesurable