Figure 3.

The Transgenic Line Expressing SLAC1 S120A Restores the slac1-2 CO₂-Insensitive Phenotype.

(A) Time-resolved relative stomatal conductance response to [CO₂] in the wild type (black), the slac1-2 mutant (light gray), wild-type SLAC1 complementation line (dark gray), and transgenic lines expressing SLAC1 S120A (magenta or green). Two independent transgenic lines were analyzed. Plants were kept under constant white light of 150 µmol m⁻² s⁻¹ at 22°C in 45% relative humidity. Conductance was normalized to the average conductance at the last 0 ppm data point. Error bars indicate ± se; n = 5 to 7.

(B) CO₂ regulation of stomatal aperture in the wild type, slac1-2 mutant, and transgenic lines expressing SLAC1 S120A. White bars indicate low CO₂ (0 ppm), and gray bars indicate high CO₂ (700 ppm) conditions. Stomata in the transgenic plants closed in response to high [CO₂]. Plants were kept under constant white light of 42 µmol m⁻² s⁻¹ at 22°C in 45% relative humidity. Error bars indicate ± se; data from four independent experiments were averaged.

(C) ABA regulation of stomatal aperture in the wild type, the slac1-2 mutant, and transgenic lines. White and gray bars indicate stomatal apertures in the absence (control) and presence of 1 µM ABA. Error bars indicate ± se; data from four to five independent experiments were averaged.