AUTHOR=Keller Adrienne B. , Phillips Richard P. TITLE=Relationship Between Belowground Carbon Allocation and Nitrogen Uptake in Saplings Varies by Plant Mycorrhizal Type JOURNAL=Frontiers in Forests and Global Change VOLUME=2 YEAR=2019 URL=https://www.frontiersin.org/journals/forests-and-global-change/articles/10.3389/ffgc.2019.00081 DOI=10.3389/ffgc.2019.00081 ISSN=2624-893X ABSTRACT=
While it has long been hypothesized that belowground carbon (C) allocation in plants is tightly coupled to nutrient uptake, empirical tests of this are rare, especially for woody plants. We grew tree saplings of nine species in soils enriched in isotopically-labeled nitrogen (N) and after several months, pulse-labeled trees with 13CO2. This approach allowed us to track how 13C allocation from foliage to absorptive root tissue related to 15N movement from soil to plant tissues as a measure of each species' N return on C investment. We hypothesized that tree species known to associate with ectomycorrhizal (ECM) fungi would have greater belowground C fluxes than those that associate with arbuscular mycorrhizal (AM) fungi, and that species with greater belowground C allocation would acquire the most soil N. Overall, we found large interspecific differences in both the amount of recently-fixed C allocated belowground and plant N uptake, yet no differences in either flux between AM and ECM trees (