A/Ci curve (net COassimilation rate, A, versus calculated internal CO2 concentrations, Ci)
A/C i curves of VC and transgenic plants, grown in soil, were measured using IRGA, as described above. Light intensity in the chamber was maintained at 400 μmol photons m-2s-1, using 6400-18A RGB (Red, Green, Blue) light source, whereas, the temperature was maintained at 25°C. To obtainA/C i curves, we measured CO2assimilation, at different CO2 concentrations. For the measurements at 2% O2, a gas cylinder containing a mixture of 2% O2 and 98% N2 was used. The gas from the cylinder was humidified and supplied to the LiCor 6400XT, where CO2 was mixed with the above gas mixture. The CE was calculated from the slope of theA/C i curve (Li et al., 2009).