Epilithic lichens and their morphological adaptations to the conditions of the White and Barents Seas coast (Russian Arctic)

The main aim of our work was to investigate the biodiversity of coastal lichens, conditions of lichen cover formation, and study the structural and functional adaptations of Lecanora intricata (Ach.) Ach. and L. polytropa (Ehrh. ex Hoffm.) Rabenh. The investigation was carried out during 2008-2012 on cliffs both along the Murmansk (the Barents Sea) coast and the southern and western shores of the White Sea. For the evaluation of species composition, and ecotopic coenotical features of epilithic lichen growing on cliffs, the geobotanical methods have been used. In addition, the anatomical, morphological and biochemical studies of Lecanora intricata and L. polytropa have been made. 91 species have been included in the total list of lichens on the White Sea coast. On the Murmask coast of the Barents Sea, 36 lichen species had revealed. On the coastal territory, the epilithic lichens inhabit the upper littoral and supralittoral zone. The lichen cover is formed by two interacting factors: the water factor (sea) and the terrestrial vegetation. Four lichen zones were distinguished in the all studying territories. They differed by the lichen species composition and effect of the sea. The first lichen’s zone is the intrazonal structure in the complex coastal lichen cover. In Lecanora polytropa and L. intricata, structural and functional features of lichens for adaptation to unstable coastal conditions were identified. The crustose biomorphs were better adapted to temperature and degree of hydration of thalli. Formation of the smallest ascospores is reproductive strategy of epilithic lichens in extreme habitats. High content of usnic acid in the studied lichen thalli allows them to exist in the open areas exposed to solar radiation and provides the biotic regulation that affects the structure of lichen cover. Optimal ratio of algal to fungal components in the thalli of these species is necessary to maintain their life in extreme environments

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

Adaptations of epilithic lichens to the microclimate conditions of the White Sea coast

Anatomical and functional features of the following three epilithic lichens Umbilicaria torrefacta, Physcia caesia, Physcia dubia were studied. These species have different morphological characteristics of thalli and occupy similar environmental conditions on supralittoral of the White Sea coast. The studied lichens are widespread in the territory of Karelia. U. torrefacta is an obligate epilithic species, Physcia caesia and Physcia dubia colonize both bark of trees and stones. Within the study area, these species were found only on coastal boulders. Photobiont of all studied lichens is unicellular green alga of the genus Trebouxia (Purvis et al. 1992). Based on the study, it was found that Ph. caesia adapts to the environmental conditions through the variability of photosynthetic pigments level which is confirmed by a strong variation of the chlorophylls a/b ratio and chlorophylls/carotenoids ratio (coefficient of variation, CV > 42%) with the stability of anatomical structures (CV ≤ 11%) – functional adaptation. Lichen Ph. dubia adapts through the variability of anatomical layers (upper cortex, algal layer, medullae, lower cortex, thallus thickness) (CV > 22%), and amounts of photosynthetic pigments (CV > 19%) – structural and functional adaptation. For U. torrefacta, the structural adaptation to environmental conditions (CV thickness of anatomical layers > 28%, CV amounts of photosynthetic pigments – 7, 8%) was recorded

Ecological and biological features of Triglochin maritima L. in the biotopes of the littoral zone with different degree of flooding on the coast of the White Sea

The study of Triglochin maritima L. was carried out on the Pomor (western) coast of the White Sea, in the Republic of Karelia (64°22'81"N, 35°93'14"E). Morphological analysis of aboveground and underground parts of the clones was performed on virginal plants. Anatomical analysis of leaf sheaths of the current year shoots, rhizomes and adventitious roots was carried out. The viability of pollen was assessed by determining the relative share of normally developed and malformed pollen grains. The content of heavy metals was determined in the soil, sea water and plant samples. The study was carried out on a model transect in the littoral zone on three test plots representing the lower littoral; the middle and the upper littoral zones. Adaptation to wave and storm impact was manifested in a well-developed system of underground organs. In the lower littoral, underground part surpasses the aboveground vegetative organs in terms of the mass and the formation of mechanical tissues. This allows the plants to anchor stronger in the substrate. Pollen analysis confirmed the adaptability of T. maritima plants to the conditions of the lower littoral by a high percentage of normal and, consequently, fertile pollen, which ensures sexual reproduction of the species. T. maritima can be considered as a Fe hyperaccumulator as the plant accumulates very high levels of Fe (22–34 g kg-1), especially in the lower and middle littoral zones, both in underground and aboveground organs. The ability of T. maritima plants to actively deposit metals was revealed on the basis of the coefficient of biological absorption of metals and makes it possible to suggest potential possibility of using the species in phytoremediation technologies on coastal territories