THE IMPACT OF AIR-POLLUTION ON THE INTEGRITY OF CELL-MEMBRANES AND CHLOROPHYLL IN THE LICHEN RAMALINA-DURIAEI (DENOT) BAGL TRANSPLANTED TO INDUSTRIAL SITES IN ISRAEL

The impact of air pollution on the integrity of cell membranes and chlorophyll in the lichen Ramalina duriaei was studied. The lichen was transplanted from a relatively unpolluted site in Israel to a highly polluted area for a period of 10 months. The seasonal variation of the percentages of Mg as detected with the aid of scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) on/in the cortical cells of the lichen was compared with changes in the chlorophyll integrity as expressed by the ratio OD 435 nm/OD 415 nm. The rate of damage of air pollution to cell membranes in the lichen was compared with the increase of S as detected on the surface of the lichen thalli retrieved from industrial sites. The present study indicates that the electric conductivity parameter reflecting the integrity of lichen cell membranes was found to express the cellular damage caused to lichen thalli transplanted to a steel smelter and to oil refineries. Symptoms of damage to cell membranes are detectable in R. duriaei long before any indication of damage becomes apparent in the photobiont chlorophyll. Magnesium seems to represent a significant leakage from intracellular sites of the thallus. The accumulation of sulfur on/in the cortical cells of R. duriaei indicates that the biomonitoring sites at the Haifa Bay are contaminated by SO2.