INVESTIGATIONS ON THE CHLOROPHYLL CONTENT OF SOME SUB-ALPINE LICHENS

The amount of chloroplast pigments, the number of symbiotic algae, as well as the proportion of the diameters of the thallus to the medulla were investigated in the subalpine lichens Alectoria ochroleuca, Cetraria islandica, Cladonia mitis, and Pseudevernia furfuracea. The results demonstrated, that there are different contents of chlorophyll and different seasonal patterns of pigment concentration depending on the species investigated. Lichens with higher pigment contents showed more distinctive seasonal variation. Among the species investigated P. furfuracea had the highest chlorophyll concentrations, C. mitis the lowest. Sun and shade populations of C. islandica exhibited marked differences in their pigment content: sun populations had a chlorophyll content more than 440% of that found in the shade populations. The number of lichen algae varied during the vegetation period. Such variation could not be correlated with the changes of pigment content. In sun and shade populations the number of symbiotic algae did not differ significantly in C. islandica. This indicates that a lower light intensity does not induce a wider algal layer but an increased chlorophyll concentration. The width of the algal layer does not alter according to seasonal patterns or ecotype (sun and shade populations). The increased number of algal cells is packed in a denser, not a wider medullar layer.