The proposed post-doc project fits the research of ecophysiology of lichens, which has been carried-out at the workplace of the proposer for last years. The proposed project will contribute to (1) the understanding of the ability of lichens to photosynthesize under very low temperatures (-20 to 5°C), (2) the evaluation of limits of physical and chemical conditions under which the chosen lichens (European and Antarctic foliose species) are able to fixation CO2 under very low temperatures and (3) the understanding of the fundamental physiological mechanisms involved in the photosynthesis of lichens under the conditions of exsiccation induced by osmotic stress. Lichens thalli will be exposed to very low temperatures, various levels of hydration, osmotic stress, irradiance as well as combination of these factors. The combination of several methods will be used for the evaluation of the lichen response, including simultaneous measurements of induced chlorophyll fluoresecence in vivo (photochemical reactions) and gasometric measurements (biochemical reactions). Some biochemical assays will be applied to determine photosynthetic pigments (HPLC: chlorophyll, carotene) as affected by experimental conditions. The gain of the proposed project will be also in the comparison of the interspecific variability in photosynthesis of the chosen lichen species under very low temperatures.

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