Figure 4.

Light induction of stomatal conductance (A) and net CO₂ assimilation (B) in wild-type and the pp mutant. Plants were grown under 9.8 mbar CO₂ and then transferred to ambient CO₂ in the dark overnight. Leaf gas exchange was measured for several minutes prior to the start of illumination at 2,000 μmol quanta m⁻² s⁻¹ (indicated by the arrow). The rate of stomatal opening for the wild-type and pp mutant was 7.8 ± 1.9 and 2.4 ± 0.5 (mmol water m⁻² s⁻²), respectively. The ambient CO₂ partial pressure was maintained at 364 μbar for the duration of the measurements. Data are the means of measurements of six different plants, error bars represent se; wild type (○) and pp mutant (•).