Nitrogen concentration does not increase in ectomycorrhizal basidiocarps with increasing altitude

摘要

Plants in arctic and alpine environments possess higher nitrogen concentrations (%N) than plants in warmer environments. High nitrogen content is considered an adaptation to nutrient poor and cold environments. Prior studies demonstrate that %N increases in plants with increasing altitude. Since fungal growth should also be limited by harsh environmental conditions that increase with altitude, it was hypothesized that fungi growing at higher altitudes would have higher %N than fungi at lower altitudes.?To investigate this hypothesis, we analyzed the total nitrogen concentrations in basidiocarps of two genera of abundant ectomycorrhizal fungi, Leccinum and Lactarius , growing at different altitudes (85 – 800 m a.s.l.) in several localities of the Fennoscandian subarctic. Contrary to our expectations, results show that nitrogen concentration in Leccinum decreases with increasing altitude, whereas there was no change for Lactarius . Thus results for fungi were decoupled from that of the associated plants. The %N in Leccinum basidiocarps was somewhat higher than that in Lactarius species (4.55 ± 1.15 and 3.50 ± 0.58, respectively). Future studies should include examination of species, host, and soil effects on %N, as well as isotope analysis of carbon and nitrogen in basidiocarps, soil, and root material.