Cell diameter and palmella formation
Cell diameter was determined by means of fluorescence activated cell
sorter (FACS, BD Fortessa, USA) using side scatter pulse width (SSC-W)
data from cells against size calibration bead standards of polystyrene
(Spherotech, USA). Briefly, six different bead standards ranging between
3 μm and 16 μm were used to plot a calibration standard curve of
amplifier gains where the pulse width was independent of peak height and
peak area. The curve was then fitted with a linear curve according to
Sharpless and Melamed (1976), and was used to transform the median SSC-W
data from a microalgal cell population of
1 × 106 cells*mL-1 into a median
cell diameter (Supplementary Fig. 2).