Amino acid uptake: a widespread ability among boreal forest plants

Amino acids constitute a potentially important source of nitrogen for plants in boreal forest ecosystems. Accordingly, it may be suggested that distinct plant species differing abilities to take up amino acids constitutes an important factor in determining plant ecosystem composition. Using GC-MS and isotopically labelled amino acids, we measured the simultaneous uptake of 15 different amino acids by 31 common boreal forest plant species. The results from this study show that all plant species tested, representing a wide variety of plant types, have the ability to take up amino acids from an incubation solution. Furthermore, uptake rates were unrelated to mycorrhizal associations as well as habitat soil amino acid concentrations and plant nitrogen availability dependence as measured by Ellenberg nitrogen indicator values. These results suggest that mycorrhiza is of minor importance for discrete plant amino acid uptake rates and further points out the potential importance of amino acids to plant nitrogen nutrition in boreal forest ecosystems.