Impacts of Cd Pollution on the Vitality, Anatomy and Physiology of Two Morphologically Different Lichen Species of the Genera Parmotrema and Usnea, Evaluated under Experimental Conditions

The heavy metal Cd accumulates in trophic chains, constituting a toxic element for photosynthesizing organisms, including the algal photobionts of lichen. Thus, as lichens respond differently to toxicity, we hypothesized that species Parmotrema tinctorum and Usnea barbata, commonly sampled Cerrado ecoregion, could be sensitive and, therefore, used biomonitor dispersion this metal. We also aimed indicate responsiveness biological markers these by exposing thalli simulated rainfall with increasing concentrations. observed both lichen are responsive stress; however, different pathways accessed. synthesis carotenoids P. production antioxidant enzymes U. barbata seem constitute relevant response strategies Cd-induced stress. morphoanatomy, cell viability, photobiont vitality index, chlorophyll fluorescence, were efficient biomarkers effects exposure tinctorum, being variables primarily associated damage photobiont. For photochemistry, enzyme activity (catalase, superoxide dismutase ascorbate peroxidase) essential reflect toxicity. However, was characterized most good bioindicator presence It can diagnosis air quality urban industrial areas or even forest influenced phosphate fertilizers.