Figure 1.

Sensitivity of the theoretical model to environmental drivers. Sensitivity of the theoretical maximum rate of Rubisco carboxylation ($V_{\mathrm{cmax}}^{\prime }$; black, solid lines) and ratio of intercellular to atmospheric CO ₂ concentration (χ; grey dotted lines, panels f, g and h) to the main environmental parameters within the model: growing season mean for irradiance (I _g, panels a and e), air temperature (T _g, panels b and f) and vapour pressure deficit (D _g, panels c and g), as well as elevation (z, panels d and h). In panels a, b, c and d, $V_{\mathrm{cmax}}^{\prime }$ values were mean centred to aid in comparison across environmental parameters. In panels e, f, g and h, values were mean centred and scaled (divided by the standard deviation) to aid comparison of $V_{\mathrm{cmax}}^{\prime }$and χ sensitivities. Sensitivity analyses were done while keeping all other environmental variables at standard levels: I _g  = 800 μmol m⁻² s⁻¹, T _g  = 25 °C, D _g  = 1 kPa, z = 0 km. Note: χ is insensitive to I _g, and as such, no dashed grey line was plotted_.