Light response curves for photosynthesis
The photosynthetic light response curves were measured by IRGA (LiCOR-6400/XT), using 6400-18A RGB (red, green, blue) light source, in the attached leaves of VC as well as in transgenic plants, under ambient CO2 (400 μmol mol-1) and ambient O2 (21%). At saturating light intensity (800 μmol photons m-2 s-1), leaves of CAx3 and CAx5 transgenic plants had 17% and 23% higher net CO2assimilation rate, than in the VC plants (Fig. 6a) . The rate of respiration in the leaves of transgenics, measured in the dark, as compared to the vector control was also higher (~8% -12%) (Figs. 6a,b ). The quantum yield of CO2fixation, as measured at limiting-light intensities (up to 80 µmol photons m-2 s-1) was 0.0407 mol mol-1 in VC plants, but it increased by 17%- 21% in CAx3 and CAx5, respectively (Fig. 6b ).