The photosynthetic parameters (Vcmax, Jmax and gm) were estimated simultaneously by fitting the A–Ci curves with the non-rectangular hyperbola version of the biochemical model of C3 (Farquhar et al., 1980) following Ethier and Livingston (2004). This method is based on the principle that mesophyll conductance (gm) is not infinite, which reduces the curvature of the A–Ci curve. The net assimilation rate (An) is given by: