Figure 7.

Effects of CA activity on PEPc activity with temperature. A, v_p modeled assuming chemical equilibrium (CA saturated) and calculated based on CA activity (CA limited). B, Concentration of HCO₃⁻ at equilibrium and calculated based on CA activity. C, v_p/v_h calculated assuming equilibrium and based on CA activity. Calculations assume a constant leaf pH of 7.2 and a 25°C hydration as well as dehydration rate constants described by Jenkins et al. (1989), with the temperature responses for the rate constants described by Sanyal and Maren (1981) applied. The model used a measured V_pmax of 450 μmol m⁻² s⁻¹, a measured k_CA of 124 μmol m⁻² s⁻¹ Pa⁻¹ at 25°C, and a constant mesophyll pCO₂ of 12 Pa at all temperatures.