Fig. 1

Live cell imaging of silicanin-1 GFP fusion proteins in individual cells of a T. pseudonana and b C. cryptica. The left panel shows an individual cell after cytokinesis with one valve SDV (green, plate-like structure) in each sibling cell. The right panel shows a cell during interphase with a girdle band SDV and additional silicanin-1-GFP bearing intracellular vesicles. Green color indicates GFP fluorescence and red color shows chlorophyll autofluorescence. Scale bar: 4 µm. Cell density measurements during the first (black dots) and second (blue dots) series of Si starvation-replenishment with c T. pseudonana and d C. cryptica. The red arrow indicates the time point at which the highest proportion of dividing cells was observed in the second Si starvation-replenishment cycle. Standard deviations (n = 3) for the first Si starvation-replenishment series were ± 0.07∙10⁶ cells∙mL⁻¹ (T. pseudonana) and ± 0.03∙10⁶ cells mL⁻¹ (C. cryptica), and for the second series ± 0.1∙10⁶ cells∙mL⁻¹ (T. pseudonana) and ± 0.04∙10⁶ cells∙mL⁻¹ (C. cryptica) (see Additional file 1: Table S1)