Cladonia Verticillaris (lichen) Can Exhibit Defense Mechanisms Against Rn-222 under Controlled Conditions

This study aimed to evaluate the effects of the Rn-222 progeny on the lichen Cladonia verticillaris under controlled conditions. The results showed resistance of the species, and few changes in the level of photosynthetic pigments. Blockage in the biosynthetic route of the major phenolic compound fumarprotocetraric acid was also identified, and accumulation of protocetraric acid, as defense mechanism against external pollutants, to maintain thallus vitality. The accumulation of the 210Pb and 226Ra, radioisotopes estimated from the daughter of 214Bi and 214Pb, was incipient. C. verticillaris showed resistance to 222Rn, with accumulation of intermediary phenolic only at the begining of experiments. Cladonia verticillaris was resistant to high doses of radiation, showing stability in the production of chlorophyll. Blockage in the biosynthesis of fumarprotocetraric acid was identified, causing accumulation of protocetraric acid, as a form of protection against the activity of Rn-222. Daughters of Rn-222 were determined, but the species reported low accumulation,  and ability of self-protection.