FIG. 1.

Growth rate, light-limited and light-saturated photosynthetic rate, and light-saturated PSII oxygen evolution rate measured for cells grown under two light intensities. (A) The A₇₃₀ of the cultures was set to 0.1, and the control (CS), ΔsigB, ΔsigD, and ΔsigBD cells were grown at the PPFD of 40 μmol m⁻² s⁻¹ (open symbols) or 80 μmol m⁻² s⁻¹ (solid symbols). (B) Oxygen evolution activity measured from cells grown for 2 days at the PPFDs of 40 or 80 μmol of photons m⁻² s⁻¹, as indicated. Oxygen evolution was measured at the same PPFD as the growth light was or under the saturating PPFD of 1,500 μmol m⁻² s⁻¹, as indicated. (C) Light-saturated PSII activity measured in the presence of 0.7 mM DCBQ. Each data point represent the mean of three biological replicates with independent liquid cultures, and the error bars denote the standard errors (SE).