Fig. 5: Growth characteristics at old and new poles.

a–c, Representative examples of different polar growth dynamics (video set B; other examples are shown in Extended Data Fig. 4). The elongation length at each pole is shown as a function of time. The lines represent the best fit to the data and can be either linear or bilinear. a, The new pole starts elongating later than the old pole (NETO). b, Both poles elongate from the beginning of the cell cycle (BEITO). c, The new pole starts elongating before the old pole (OETO). The legend in a also applies to b and c. d, Joint distribution of the timings when the old and new poles start growing in neutral (n = 147) and acidic pH (n = 101) (video set B and C, respectively). e, Distribution of the elongation speed at each pole in neutral and acidic pH (video set B and C, respectively). f, Growth rate and elongation speed versus age in neutral (n = 147) and acidic (n = 101) growth conditions. Simulations of the proposed model are carried out using parameters derived from experimental data. Growth rate trends as a function of age and elongation speed versus age are compared between simulations (black) and experiments (red) for neutral pH and acidic pH conditions. The dots and error bars represent mean ± s.e.m. Note that here we are showing numerical simulations with a comparable number of cells to that used in the experiment, leading to significant fluctuations. These fluctuations can obscure the deviations from linearity predicted by the full model, which accounts for different subpopulations. The model predictions, averaged over a larger population of cells, are shown in Extended Data Fig. 4. Age in f is unitless.