Fig. 7
From: Cytokinin functions as an asymmetric and anti-gravitropic signal in lateral roots
Cytokinin affects cell elongation and number in lateral roots. a Sketch shows a simplified geometry of a lateral root (LR). LR model consists of tip and elongation zones. The cell elongation rate (visualized as red spot inside the cell) linearly increases from lower flank towards the upper flank of the LR (up to three-fold) based on estimates derived from previous work7. Bottom panel, color coding bar for cell elongation rates. b Time-lapse model simulations (screenshots) which lead to the in vivo observed LR bending (63°) after ~8 h. c Left panel corresponds to b. Right panel, 10% decrease in elongation rate only on the upper root flank (white arrow heads). Each simulation represents LR status after 9 h of dynamic elongation. d Time evolution of set-point angle corresponding to different scenarios in c. e Representative image and quantification of first two elongated cells of lateral roots in stage II. f Quantification of the cell number in the upper and lower meristem of Col-0 and ckx2-1. g Representative images and GSA distributions of Col-0 wild-type, CDKB1;1 DN (dominant negative) and cdkb1;1 cdkb1;2. Kolmogorov–Smirnov test P-values: ***P < 0.001 (compared to Col-0). Mean ± SEM, n = 5 plates (16 seedlings with 100–180 LRs per plate). Scale bars, 2 mm. h Quantification of the cell number in the upper and lower meristem of Col-0, CDKB1;1 DN and cdkb1;1 ckdb1;2. e, f, h One-way ANOVA P-values: *P < 0.05, **P < 0.01, ***P < 0.001. Horizontal lines show the medians; box limits indicate the 25th and 75th percentiles; whiskers extend to the min and max values, n = 10–20 individual LRs. Scale bar, 10 µm. e–h Experiments were repeated at least three times
