Figure 5.

Photosynthesis.

(A) Photosynthesis at 170 μmol m⁻² sec⁻¹ and ambient CO₂.

(B) Photosynthesis at 220, 350, or 700 μmol m⁻² sec⁻¹ and ambient CO₂.

(C) Photosynthesis in saturating light and saturating CO₂.

(D) CO₂ concentration inside the leaf ([Ci]).

Plants were grown in a greenhouse in natural irradiance supplemented with 170 μmol m⁻² sec⁻¹, with light intensities increasing to ∼600 μmol m⁻² sec⁻¹ on sunny days. TK activity was measured in each leaf area after the measurement of photosynthesis was completed. The results are given as means ±se, and each individual data point corresponds to five to seven separate wild-type (WT) plants (closed symbols) or three to seven transformants (open symbols). Photosynthesis was measured at 350 ppm CO₂ on an overcast day (A) without additional light or (B) with supplementary light to bring the intensity in the cuvette to 220 (circles), 350 (triangles), or 700 (diamonds) μmol m⁻² sec⁻¹, and (C) at ∼5000 ppm CO₂ and 700 μmol m⁻² sec⁻¹. [Ci] (D) was calculated from the rate of photosynthesis and stomatal conductance, as determined in parallel with photosynthesis.