MINERAL-COMPOSITION OF SOME LICHEN SPECIES

Mineral analysis (Ca++, K+ et Mg++) have been done in ten moutain lichens species (9 terricolous, 1 corticolous). Generally, it can be observed that Ca++ > K+ > Mg++ except in Peltigera aphthosa where K+ > Ca++. Statistical tests showed correlations between contents of Ca++, K+ and Mg++ in lichens and other factors : contents of Ca++, K+ and Mg++ in substrate (humus and bark), pH and attitude. These correlations can be unsignificant or negative but are generally positive. Different forms of calcium have been found in lichens : phosphates and carbonates > oxalates > soluble calcium. Observations with the electronic microsonde showed the histological mineral localization in lichens : Ca++ in fungal tissues, K+ and Mg++ in the algal layer.