Content of photosynthetic pigments in the shoots of stonecrops (Sedoideae) in the forest-steppe of Western Siberia

The purpose of this work was to determine the content of chlorophylls and carotenoids in the shoots of stonecrops at different phases of seasonal development. The study was carried out at the Central Siberian Botanical Garden of Siberian Branch of the Russian Academy of Sciences (Novosibirsk) in 2022. The objects were 8 species of the subfamily Sedoideae, belonging to the genera Aizopsis, Hylotelephium, and Sedum. The concentrations of chlorophylls a and b, as well as carotenoids in the freshly collected raw material were determined by the spectrophotometric method. It was found that during the flowering phase, the total chlorophyll content in the vegetative shoots of stonecrops ranged from 40,0 to 398,5 mg%, and in the shoots with inflorescences – from 31,8 to 216,6 mg% per absolutely dry raw material weight. The corresponding indicators for carotenoids were 7,4–84,1 mg% and 10,8–36,0 mg%. At the end of the growing season, the pigment pool increased in winter-green species, providing the accumulation of plastic substances for the winter period. The ratio of chlorophylls a and b in autumn ranged from 0,6 to 2,6, the ratio of chlorophylls and carotenoids ranged from 3,1 to 4,6. In summer, the indicators varied in a wider range due to the different heliophilicity of stonecrops. The data demonstrate a low content of photosynthetic pigments in stonecrops and a high interspecific variability of quantitative indicators of the pigment pool during adaptation to the forest-steppe conditions of Western Siberia.