Figure 6.

Oxygen evolution rates of Synechocystis sp. strain PCC 6803 cultures in increasing intensities of 625-nm light, recorded with MIMS. ¹⁸O₂ was added at the start of the experiment to monitor oxygen consumption in the light. Depicted are net photosynthesis (which is the sum of the measured oxygen production and the consumption [diamonds]) and respiration (squares). A, BG-11 with 0.5 mm NaHCO₃. B, BG-11 with 50 mm NaHCO₃. Orange symbols, 625-nm light only; red symbols, 625-nm light + 25 µmol photons m⁻² s⁻¹ 730-nm light. Data shown are averages of biological duplicates with sd. [See online article for color version of this figure.]