Figure 4.

Images of (1 − Φ/Φ_m)_i taken before (A) and during (B and C) the ABA treatment of a leaflet fraction area of R. rubiginosa at normal (A and B) and high (C) external CO₂ mole fraction for 1 min. Leaflet atmosphere was 330 μmol mol⁻¹ CO₂ (A and B) or about 7400 μmol mol⁻¹ CO₂ (C), 0.1% O₂, and 65% RH. The photon flux density was 420 μmol m⁻² s⁻¹. The bar indicates 4 mm. Pixel intensity was scaled using an 8-bit gray scale where black and white correspond to a photochemical yield of 0 and 0.6, respectively (A and C), or 0 and 0.4, respectively (B). For the whole leaflet area (5.5 cm²), A_n and g_s were 16.1 (A), 4.1 (B) μmol m⁻² s⁻¹, and 165 (A), 27 (B) mmol m⁻² s⁻¹, respectively.