Towards a universal model for carbon dioxide uptake by plants

Han Wang*, I. Colin Prentice, Trevor F. Keenan, Tyler W. Davis, Ian J. Wright, William K. Cornwell, Bradley J. Evans, Changhui Peng

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    235 Citations (Scopus)

    Abstract

    Gross primary production (GPP) - the uptake of carbon dioxide (CO2) by leaves, and its conversion to sugars by photosynthesis - is the basis for life on land. Earth System Models (ESMs) incorporating the interactions of land ecosystems and climate are used to predict the future of the terrestrial sink for anthropogenic CO21. ESMs require accurate representation of GPP. However, current ESMs disagree on how GPP responds to environmental variations1,2, suggesting a need for a more robust theoretical framework for modelling3,4 . Here, we focus on a key quantity for GPP, the ratio of leaf internal to external CO2 (χ). χ is tightly regulated and depends on environmental conditions, but is represented empirically and incompletely in today's models. We show that a simple evolutionary optimality hypothesis5,6 predicts specific quantitative dependencies of χ on temperature, vapour pressure deficit and elevation; and that these same dependencies emerge from an independent analysis of empirical χ values, derived from a worldwide dataset of >3,500 leaf stable carbon isotope measurements. A single global equation embodying these relationships then unifies the empirical light-use efficiency model7 with the standard model of C3 photosynthesis8, and successfully predicts GPP measured at eddy-covariance flux sites. This success is notable given the equation's simplicity and broad applicability across biomes and plant functional types. It provides a theoretical underpinning for the analysis of plant functional coordination across species and emergent properties of ecosystems, and a potential basis for the reformulation of the controls of GPP in next-generation ESMs.

    Original languageEnglish
    Pages (from-to)734-741
    Number of pages8
    JournalNature Plants
    Volume3
    Issue number9
    DOIs
    Publication statusPublished - 1 Sept 2017

    Keywords

    • Biogeochemistry
    • Macroecology

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