Inside out: Measuring the effect of wood anatomy on the efflux and assimilation of xylem–transported CO₂

Journal Article · 23 August 2021 · Plant, Cell and Environment

DOI: https://doi.org/10.1111/pce.14172 · OSTI ID:1818940

Stutz, Samantha S.  ^[1]; Anderson, Jeremiah  ^[2]

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1. Univ. of Illinois at Urbana-Champaign, IL (United States)
2. Brookhaven National Lab. (BNL), Upton, NY (United States)

Carbon dioxide concentrations (including aqueous CO₂, carbonic acid, bicarbonate, and carbonate) in woody tissues can be up to 750 times higher than atmospheric CO₂ concentrations, ranging from <1% to >26% vs atmospheric ~0.04% (Fig. 1) (Teskey et al. 2008). CO₂ formed through respiration is generally assumed to diffuse to the atmosphere from tissues adjacent to where it is produced. Here, this CO₂ buildups in the stem due to the diffusional barriers in woody and bark tissues. CO₂ in the stem has three fates: 1) it can be refixed for photosynthesis, 2) it can be used for anaplerotic reactions, or 3) it can exit the plant either adjacent to where it was produced (radial diffusion) or in an area remote from its point of origin (xylem-transported CO₂). Not accounting for assimilation of xylem-transported CO₂ may result in underestimating total plant photosynthesis. Alternatively, overlooking the transport of CO₂ away from its point of origin complicates the estimation of respiration in stems, branches, or even leaves. For example, CO₂ efflux from the stem may not solely represent stem respiration, but it may represent CO₂ generated through respiration in areas remote from the point of efflux (Stutz et al., 2017). Additionally, wood anatomy and branching architecture likely influence how much and how far xylem-transported CO₂ travels (Fig. 2). Few studies have combined measurements of both the efflux of xylem-transported CO₂ from trees together and the assimilation of xylem-transported CO₂. Excitingly in this issue of Plant, Cell & Environment, Salomón et al. (pp. ) demonstrate the importance of xylem-transported CO₂ in plants with different wood anatomies by comparing the amount of xylem-transported CO₂ used for photosynthesis to the amount effluxed.

• Research Organization: Brookhaven National Laboratory (BNL), Upton, NY (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: SC0012704
• OSTI ID: 1818940
• Report Number(s): BNL--222039-2021-JAAM
• Journal Information: Plant, Cell and Environment, Journal Name: Plant, Cell and Environment Journal Issue: 11 Vol. 44; ISSN 0140-7791
• Publisher: WileyCopyright Statement
• Country of Publication: United States
• Language: English