ACTIVITY OF SUPEROXIDE-DISMUTASE AND MALONDIALDEHYDE CONTENT IN LICHENS ALONG AN ALTITUDE PROFILE

The occurrence of the superoxide dismutases and the malondialdehyde co ntent in the lichens Hypogymnia physodes and Pseudevernia furfuracea c ollected from different altitudes in the Central Eastern Alps (altitud e runs from 1080 m up to 1940 m) were determined. Both specific SOD ac tivity and MDA content were much higher in P. furfuracea than in H. ph ysodes. Maxima were determined in Pseudevernia furfuracea at 1270 m an d at higher altitudes (1800-1940 m). In crude extracts six SOD isozyme s have been characterized by native PAGE and identified as Cu/Zn-, Mn- and Fe-SODs by inhibition studies. A dominant Cu/Zn-SOD (SOD 6 with l ow mobility on the gels) contributed 60 to 70% of the total activity f ound on the gels. By comparison, SOD activity was determined in Cetrar ia islandica and Cladonia verticillaris. The role of SOD in detoxifica tion and adaptation mechanisms to environmental stress factors, partic ularly to ozone, is discussed.