Scientific publications

Siberian spruce (Picea abies ssp. obovata (Ledeb.) Domin) is one of the dominant species in north-taiga forests and changes in the chemical composition (e. g. tannins) of spruce needles can significantly affect biogeochemical cycles in the areas of its distribution. Variations in the tannin content of Picea abies ssp. obovata needles of different ages among different elementary biogeoareas (EBGA) in dwarf shrub-true moss spruce forests in the Murmansk Region were studied. It was found that the concentration of soluble proanthocyanidins (p < 0.05) decreased with age in needles of spruce trees in all the studied elementary biogeoareas. This pattern was less pronounced for cell wallbound tannins, since the age-related variation of their content in spruce needles was only 4.0 to 8.8 mg/g, while soluble tannins ranged from 31.4 to 88.8 mg/g. Mature trees of two age categories (older than 200 years and an average of 150 years) did not differ in the content of tannins in needles of matching ages. Tannin levels in young (current-year and 1‑year-old) needles of juvenile spruce (30–40 years old) were significantly higher than in needles of the same age in mature trees. A rise in the content of soluble tannins associated with a deficit of nitrous nutrition happened only in the most physiologically active young (current-year and 1‑year-old) needles.