Growth rates of Synechocystis sp. PCC 6803 substrains GT-L (white circles), GT-B (red triangles) and PCC-B (blue squares) under increasing red, blue and white light.

A, B–Red light was set to intensities of 25–660 μmol(photons) m^-2 s^-1 and it was supplemented with 25 μmol(photons) m^-2 s^-1 of blue light. The experiments were performed at 32°C (A) and 35°C (B). C–Red light of 220 μmol(photons) m^-2 s^-1 was supplemented with 25–220 μmol(photons) m^-2 s^-1 of blue light under 32°C. D–Red light of 220–8 μmol(photons) m^-2 s^-1 was supplemented with white light of 0–790 μmol(photons) m^-2 s^-1 (at 32°C) in order to keep the red photons (as a combination of red light and part of the white spectra) constant at 220 μmol(photons) m^-2 s^-1 (according to [19]). All experiments were carried out in a quasi-continuous regime as described in the main text under growth saturating CO₂ concentration of 5 000 ppm. Each point represents average of at least four independent experiments, error bars represent standard errors. The dashed lines in panels A and B represent fitting of the data points by the function derived by Platt et al. (1980) [51]. The dashed lines in panels C and D represent linear fitting of the data points by the least squares method. Legend in panel D represents particular combinations of white light (W) and red light (R) in units of μmol(photons) m^-2 s^-1.g.