Figure 3.

Net CO₂ assimilation rate, the ratio of intercellular to ambient pCO₂ (p_i/p_a), and carbon isotope discrimination (Δ¹³C) as a function of the rate constant of leaf CA (k_CA μmol m⁻² s⁻¹ Pa⁻¹). The inset in c shows the expanded scale of Δ¹³C where net CO₂ assimilation is relatively constant. Each point represents a measurement made on a different plant grown in a glasshouse at ambient CO₂ or in a growth cabinet at 1% CO₂: wild-type plants grown at ambient CO₂ (□); anti-CA plants grown at ambient CO₂ (▪); wild-type grown at 1% CO₂ (○, ▵); and anti-CA plants grown at 1% CO₂ (•, ▴). Measurements were made at 2,000 μmol quanta m⁻² s⁻¹, leaf temperature of 30°C, and an inlet CO₂ concentration of either 38 Pa in air (▵, ▴) or 52 Pa of CO₂ in a 90.5 kPa of N₂ and 4.8 kPa of O₂ gas mixture (□○, ▪•). The lines represent the best fit for all measurements (wild-type and anti-CA plants) made at either 38 or 52 Pa of CO₂.