Figure 2.

a, Net CO₂ assimilation rate. b, Ratio of intercellular to ambient CO₂ partial pressures (p_i/p_a). c, Carbon isotope discrimination (Δ¹³C). d, Bundle sheath leakiness to CO₂ (φ) as a function of PFD (μmol quanta m⁻² s⁻¹). Measurements were made at a pCO₂ of 52 Pa, a pO₂ of 4.8 kPa, and a leaf temperature of 30°C. Shown are the means ± the se of measurements made on three to five leaves from two F. bidentis wild-type plants. Values for ξ (Eq. 1) were 29.9 ± 0.75, 15.7 ± 0.54, 7.11 ± 0.24, 5.5 ± 0.23, and 4.9 ± 0.17 at PFDs of 150, 300, 800, 1,400, and 2,000 μmol quanta m⁻² s⁻¹. φ was calculated from Equation 5, assuming V_p/V_h = 0.