FIGURE 1.

Iron availability and media viscosity jointly influence growth and pyoverdine production in the ancestral Pseudomonas aeruginosa. (a) Strain growth (OD₆₀₀) in the nine different environments, which vary in medium viscosity (amount of agar added: low =0.0%; intermediate =0.1%, high =0.2%) and iron availability (low =0 µm, red line; intermediate =2 µm, yellow line; high =20 µm, blue line). (b) Pyoverdine investment, shown as log‐transformed pyoverdine fluorescence values normalized by OD, in all nine experimental conditions. Each square represents the mean of 16 independent populations, whereas the vertical bars represent the standard error of the mean