Fig. 2.

Linear relationship between net CO₂ assimilation rate A and I_incΦ₂/4, where Φ₂ is set to be $\mathrm{\Delta }F/F_{\mathrm{m}}^{{}^{\prime }}$ and I_inc is ≤ 200 μmol m⁻² s⁻¹ (each point represents the mean of measurements on leaves from four replicated plants), for nonphotorespiratory condition (2% O₂ combined with C_a = 1000 μmol mol⁻¹). The intercept of regression lines gives an estimate of −R_d (see Yin et al., 2011), and the slope gives an estimate of the calibration factor s for converting $\mathrm{\Delta }F/F_{\mathrm{m}}^{{}^{\prime }}$ into the linear electron transport rates (see the text)