| heal.abstract |
Samples of three species of corticolous lichens (Anaptychia ciliaris, Lobaria pulmonaria and Ramalina farinacea) were collected from 22 Quercus spp. stands (sites) distributed in the plain (250 km(2)) of Megalopolis (Peloponnesos) southern Greece, and at various distances, elevations and directions with respect to a lignite power plant (550 MW), releasing pollutants from stacks of 110 and 180 m height. The concentrations of several metals (Ca, Cd, Cu, Fe, Mn, Pb and Zn) and of total sulphur were determined in the thalli of the above species as well as the levels of a number of biochemical parameters (thallus pH, total proteins, reducing sugars and chlorophyll alpha/phaeophytin alpha ratio). The statistical analysis of the data showed significant differences among the sites for the concentrations of elements and the biochemical parameters; multiple linear regression showed that the values of sulphur and most metals were partly due to the distance (negative effect), and elevation (positive effect) of the sites from the power plant. Significant differences were also found among the three species. Total protein contents were 1.66, 6.97 and 8.79 mu g mg(-1), the contents of reducing sugars 18.84, 46.12 and 33.18 mu g mg(-1) and the lichens' thallus pH were 5.76, 5.05 and 4.80 in A. ciliaris, L. pulmonalia and R. farinacea, respectively. The most sensitive to SO2 species, L. pulmonaria, had (a) the highest concentration of sulphur (0.27%) and (b) the largest value of reducing sugars due, perhaps, to a breakdown of polysaccharides. The ratios of chlorophyll alpha/phaeophytin alpha in the three species (0.55-0.67) suggest a substantial degradation of chlorophylls. The Cd contents in the three species (3.09, 3.42 and 3.80 mu g g(-1)) are considered close to toxic levels for lichens while those of Pb (8.60, 9.76 and 11.18 mu g g(-1)) are below toxic levels. The negative correlations between Cd concentration and total protein content in A. ciliaris and L. pulmonaria are of particular interest. Negative correlations were also found between total sulphur and thallus pH in all three species. Cluster analysis revealed that the variables examined tend to form three clusters. (C) 1998 Elsevier Science B.V. |
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