Adaptations of cyanobacterium Nostoc commune to environmental stress: Comparison of morphological and physiological markers between European and Antarctic populations after rehydration

Availability of water may influence activities of all living organisms, including cyanobacterial communities. Filamentous cyanobacterium Nostoc commune is well adapted to wide spectrum of ecosystems. For this reason, N. commune had to develop diverse protection strategies due to exposition to regular rewetting and drying processes. Few studies have been conducted on activities, by which cyanobacteria are trying to avoid water deficit. Therefore, the present study using physiological and morphological parameters is focused on comparison between European and Antarctic ecotypes of N. commune during rewetting. Gradual increase of F V /F M ratios, as the markers of active PS II, demonstrated the recovery processes of N. commune colonies from Europe as well as from Antarctica after time dependent rehydration. During the initial hours of rewetting, there was lower content of soluble proteins in colonies from Antarctica in comparison to those from Europe. Total content of nitrogen was higher in European ecotypes of N. commune. Significantly higher frequency of occurrence of heterocysts in Antarctic ecotypes was observed. The heterocyst cells were significantly longer in Antarctic ecotypes rather than European ecotypes of N. commune.