Fig. 4. Comparison of observed (symbols) (data adapted from references) and simulated A using the default CROPGRO photosynthetic equations (dashed lines) or the full Farquhar photosynthetic equations (solid lines). (a) Griffin and Luo (1999) for plants grown in 350, (b) Griffin and Luo (1999) for plants grown in 700 µmol CO₂ mol^–1, (c) Sims et al. (1998), and (d) Harley et al. (1985). Arrows indicate the intercellular [CO₂] equivalent to ambient [CO₂] treatments.