The concentration of neutral sugars in stemflow with respect to tree species and canopy phenophase

It is well known that stemflow contains soluble carbohydrates. While neutral sugars play an important role in tree metabolism, data on the concentrations of neutral sugars in stemflow are scant. Neutral sugar inputs via stemflow could influence soil solution chemistry and microbial activity in near-trunk soils. Accordingly, to fill the existing knowledge gap, this study quantifies stemflow neutral sugar concentrations with respect to tree species and phenophase. The concentrations of L-rhamnose, D-glucose, D-mannose, D-galactose, L-arabinose, and D-xylose in stemflow were determined using orbitrap liquid chromatography-mass spectrometry as a function of both tree species (Betula lenta L. [sweet birch], Fagus grandifolia Ehrh. [American beech], Liriodendron tulipifera L. [yellow poplar], and Pinus rigida Mill. [pitch pine]) and phenophase (emergence, leafed, senescence, leafless for deciduous species and emergence, leafed-spring/summer, senescence, leafed-winter for pine). Overall, the median concentrations for all sugars were higher for yellow poplar and pitch pine, and by phenophase, the leafless (or leafed-winter) phenophase had the highest (galactose, arabinose/xylose) or second highest (rhamnose, glucose, mannose) median concentrations for all sugars. We recommend the quantification of neutral sugar concentrations and fluxes in studies seeking a more comprehensive understanding of the physiological ecology of wooded ecosystems.

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Funding note: This research was supported by funds from the US National Science Foundation (Award No. GCR-CMMI-1934887).