Growth curves of S. obliquus wild type and five selected starch mutants. Solid lines and filled circles represent strains cultivated under nitrogen-depleted conditions; dotted lines and open circles represent nutrient-replete conditions. The greyscale lines visualize the wild type growth curve in the starchless mutant plots. The values are derived from duplicate cultures. Deviation from the duplicate average is indicated by the error bars. slm, starchless mutant; wt, wild type.