Rila Mountain is the highest mountain on the Balkan Peninsula and is characterized with specific microclimate. It has been revealed that with the increase of the altitude, the differences in environmental conditions change at a great extent. In mountain conditions plants have to cope with combined environmental factors such as altitude, temperature, prolonged UV irradiation, and etc. The aim of this study is to assess whether pigment content in wild growing plant species is altitudes dependent. Five wild species, characteristic of the ecosystems in Rila Mountain: Fragaria vesca L. (Rosaceae), Myosotis sylvatica Ehrh. (Boraginaceae), Achillea millefolium L. (Asteraceae), Epilobium angustifolium L. (Onagraceae) and Dactylis glomerata L. (Poaceae) were used as plant material. Plants were collected from three different altitudes (Sofia-595 m; Rila Mountain-1500 m a.s.l. and 1782 m a.s.l.) in July-August in growing season of 2020. Sofia was chosen as control altitude. Pigment content was applied as endpoint. Our data showed that the levels of total chlorophylls, chl. a, chl. b and total carotenoids for plants growing at 1500 m a.s.l. were lower or similar to those measured at Sofia altitude for F. vesca, M. sylvatica, A. millefolium, E. angustifolium and D. glomerata L. There is no change in chlorophyll a/b ratio detected in plants at 1500 m a.s.l. altitude and 1782 m a.s.l. in the five investigated species. Based on our results it could be reveal the adaptation mechanism and survival strategies of F. vesca, M. sylvatica, A. millefolium, E. angustifolium and D. glomerata under complex environmental stresses in both mountain altitudes. On the other hand no change in the chlorophyll a/b ratio could be an indication that altitudes have no permanent damage on the leaf photochemical system. It is known that chlorophyll content in plants is an indicator of their response to the habitat, weather, anthropogenic conditions. Because of the fact that in mountain conditions the effect of altitude is combined with other abiotic factors and that pigment content is very variable depending on many factors further studies using other plant species are needed for better understanding of the mechanisms of interaction between factors and plant response.

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Tsveta Angelova, Christo Angelov, Nikolai Tyutyundzhiev, Svetla Gateva, Gabriele Jovtchev, "Does altitude have an effect on pigment content of wild growing plants in rila mountain?", RAD Conf. Proc, vol. 5, 2021, pp. 15-20, http://doi.org/10.21175/RadProc.2021.03