Fig. 1.

Crossover temperatures of photosynthesis for C₃ and C₄ with the change of CO₂ concentration under different water conditions. Light intensity was 1,400 μmol⋅m⁻²⋅s⁻¹ for all model runs. J_max/V_cmax = 2.1 for C₃ and J_max/V_cmax = 4.5 for C₄. Solid black line: VPD = 0.1 kPa, ψ_s = 0 MPa; dashed black line: VPD = 0.625 kPa, ψ_s = −0.5 MPa; dot-dashed black line: VPD = 1.25 kPa, ψ_s = −1 MPa; dotted black line: VPD = 1.875 kPa, ψ_s = −1.5 MPa. The circle and error bars indicated the average and confidence intervals of crossover temperature in Collatz (8).