Factors of Carbon and Nitrogen Contents in the Fine Roots of Plants in the Middle Urals

—Some factors influencing C and N contents in fine plant roots were studied in the Middle Urals. They included ecological (edaphic) features of habitats; type of root symbioses (the capability for symbiotic nitrogen fixation and formation of different mycorrhiza types); and ecological strategies of species. Samples of fine roots from woody and herbaceous plants and of the upper soil layer were collected in two industrial dump sites and in an area with natural communities. In each area, samples were taken from forest and meadow habitats. The content of C or N in the species from the sampling plot served as an observation unit. A total of 83 estimates were analyzed. As a result, differences were revealed between the key factors influencing the content of each element in fine roots: the C content is determined mainly by the type of mycorrhiza, while the determinant factor for the N content is the capability for symbiotic nitrogen fixation; ecological features of habitats and the type of plant ecological strategy are the second and third factors influencing the C and N contents. The patterns of N accumulation in the roots of plants with different ecological strategies and with different types of mycorrhizas do not fully replicate the patterns of N accumulation in their leaves.