Figure 8.

COR-induced decrease in photosynthetic efficiency is eliminated by high CO₂. A, Diagram of the experimental setup. Following the initial acclimation in the imaging chamber, plants were treated (arrow) with water (mock) or COR 4 h after the dawn of day 1. One set of plants (high CO₂) was subsequently treated with 2,000 µL L⁻¹ CO₂ for 2 h, beginning 1 h before dawn (hashed region) of day 2 (1 d after COR treatment). A second set of control plants (ambient CO₂) was maintained at ambient CO₂ levels for the duration of the experiment. Chlorophyll fluorescence images were taken at the time points denoted by X. B, Representative false-color images of Φ_II taken at the indicated times after dawn of day 2. C, Φ_II values calculated from chlorophyll fluorescence images of plants treated with high CO₂. Data show means ± sd of three independent replicates. For each replicate, Φ_II was quantified for two to three actively growing leaves per plant.