Structural and functional adaptations of epilithic lichens of Umbilicaria genus in the White Sea coastal conditions

Anatomical and physiological characteristics (width of anatomical layers and the amount of photosynthetic pigments) of two epilithic lichen species Umbilicaria torrefacta (Lightf.) Schrader and U. deusta (L.) have been studied. The study took place on the supralittoral zone on the coast of the White Sea in two points: Kolezhma village and Keret village in 2014 and 2015. Ecological plasticity of mycobiont which contacts the environment and gives a niche to the photobiont have been revealed, based on the analysis of variance in the study of anatomical structures of two different types of habitats and between different samples of the same species. Coastal conditions provide favorable levels of humidity and light for the U. torrefacta and U. deusta species. This allows symbiotic organism to maintain a symbiotrophic balance due to the plasticity of the fungal symbiont which contacts the abiotic environment. At the same time these adaptation mechanisms do not include functional changes, such as photosynthetic apparatus of the autotrophic symbiont, conditions for which are set by the fungal organism. U. deusta and U. torrefacta species only show structural adaptations - the adaptations that follow the path of anatomical structure changes and the relative stability of the physiological parameters. The study shows that anatomical structure of thalli varies more significantly between the two species than within samples of the same species