Figure 7.

Filament elongation occurs in three phases. A–C, Heat maps of area extension (A), growth anisotropy (B), and cell proliferation (C) displayed on the digitally extracted filament surface. Dotted lines in (B) mark filament outlines for clarity. Heat maps generated between consecutive time points are displayed on the first time point. White signals in (A–C) at 12 DAI indicate cell outlines. D–F, Quantification of area extension (D), growth anisotropy (E), and relative proportion of cell divisions (F). Violin plots contain 95% and boxplots 90% of the values, respectively. The boxes indicate the range between the first and the third quartile and the whiskers include 90% of the values. Lines represent median and dashed lines represent the mean (nine independent time-lapse series, n > 127 cells). G, Contribution of different portions of the early filament to the final length of the fully elongated filament. Graph represents relative contribution of equal segments marked at 6 DAI to the final filament length at 12 DAI. Time series of the developing filament divided at 6 DAI into five equal portions marked with different colors. Scale bars, 100 µm in (A–C) and (G).