Fig. 4

Volvox cultures. a Stock cultures kept in temperature- and light-controlled growth chamber. b Volvox culture in 500-mL flask plugged with silicone sponge stopper and aerated via cotton-plugged Pasteur pipette. Individual spheroids are just barely visible to the naked eye. c LED growth chamber for synchronizing cultures. Culture flasks similar to that in panel b sit in a temperature-controlled acrylic water bath and are lit from below by red and blue LEDs that can be programmed for a diurnal regime. A gas manifold above the flasks provides pressurized air for culture aeration