XVI International Botanical Congess

One of several mechanisms protecting from desiccation-induced damage is the ability to scavenge free radicals formed during desiccation. For a fungal line the transition to a lichenized state is accompanied by increased oxidative stress. Lichenized fungi have higher nucleotide substitution rates than very closely related nonlichenized fungi. It can be assumed that free radical attack to DNA and RNA molecules took place during lichenization. Lichenized fungi have an outstanding capacity to scavenge free radicals indeed. To study interactions between mycobiont and photobiont, antioxidants extracted from thalli of the lichen Cladonia vulcani have been compared with data recorded from its cultured mycobionts and photobionts. During desiccation and rehydration of the intact thalli and of the isolated algae and fungi changes in the content of glutathione, tocopherols and pigments are described.