Fig. 1

Lipid accumulation in Cyclotella cryptica under silicon deprivation. Grayscale image of C. cryptica in (a) silicon replete medium, 0 h lipid uninduced, or (b) 48 h silicon deplete, lipid induced. c, d Respective composite images of chlorophyll autofluorescence (red) and fluorescent lipophilic dye BODIPY (green). e, f Differential interference contrast image of silicon replete (e) and 96 h silicon deplete, lipid induced, with red arrows identifying lipid droplets (f). Scale bars 5 μm