Fig. 4: Reduction of GSK3 activity decreases the CC ratio in planta.

a, b Toluidine blue-stained transverse sections through mock- (DMSO, a) and bikinin-treated (b) hypocotyls. SE, white empty cell; CC, dense purple cell. c, d Expression of pSEOR1:SEOR1-RFP (magenta) and pSUC2:YFPnls (green) in 10-day-old hypocotyls treated with DMSO (c) or 10 µM bikinin (d) for 10 days (n = 8). Confocal images of transverse (left) and longitudinal sections (right). e–g Toluidine blue-stained transverse sections for 10-day-old hypocotyls of Ws (wild type, e and gsk3 high-order mutant plants (gsk3 quadruple, f and gsk3 hextuple, g). Arrowheads: ectopic SEs at the PPP position; the ratio of individuals showing ectopic SEs is marked on the upper right of the image. h, i Box-and-whisker plots of SE/CC ratios (%) in Ws and gsk3 high-order mutants (h), and WT plants treated with or without 10 µM bikinin (i) calculated from toluidine blue-stained sections. Median values were indicated by central lines. The first (Q1) and third (Q3) quartile were shown as a box. Lines show the range of Q1 + 1.5× interquartile and Q3–1.5× interquartile. Dots indicated distributions of each sample. Numbers of individuals are marked (n = 12–26). Asterisks: significant differences determined using Dunnett’s or Student’s t test (**P < 0.005). j, k GUS staining of 10-day-old hypocotyls of pSK11:GUS (j) and pSK12:GUS (k) plants. l GUS staining of 11-day-old hypocotyls of pDWF4:GUS plants. GUS staining patterns on the cross section (left) and subsequent toluidine blue-stained section (right) were shown. GUS expression pattern was overlapped with toluidine blue staining. Scale bars: 10 µm (a–g); 20 µm (j, k); 50 µm (l).