Fig. 4

Growth phenotype of the Δcse mutant under different growth conditions. Growth curves a-d of wild-type (WT) and Δcse cultures monitored using total proteins (a and c) and chlorophyll concentrations (b and d) under 3% CO₂. Cultures were grown either in regular BG11 medium (a and b), or in BG11₀ medium lacking combined nitrogen (c and d). Data points represent mean values from three biological replicates (n = 3), error bars show standard deviations. Significant differences between WT and Δcse samples are indicated with asterisks (t-test P <  0.05). Absorption spectra of WT and Δcse cultures were recorded after growing cultures for 5 days in BG11 (e) or BG11₀ (f)