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

Four lichen species: Hypogymnia physodes, Pseudevernia furfuracea, Parmelia saxatilis, and Plaiismatia 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 (P-N), fluorescence parameters (FvFm, F-m, F-m/F-0 ), chlorophyll a+b content, and phaeophytinization quotient (O.D.435/O.D.41 5). P-N intensity, chlorophyll a+b and O.D.435/O.D.415 were reduced only in P. furfuracea collected from Kopa, which is in agreement with the Hawkswor th-Rose scale of sensitivity of lichens to air pollution. Fluorescence para meters were significantly lowered in all lichens coming from the more pollu ted site (except of F-v/F-m and F-m/F-0 in P. saxatilis). Parameters based on chlorophyll fluorescence measurements enable to reveal the very early si gns of decreased photosynthetical capacity of the thalli, caused by air pol lution, before changes in the other photosynthetic parameters become mesura ble.