Fig. 1: Distribution of FT and co-localization with FD at the SAM during floral transition.

a, Schematic depicting the timing of developmental transitions in Arabidopsis. Scale bars, 20 µm (cross-sections; inset) and 1 cm (plant images). b–i, Confocal images of SAM cells co-expressing gFT::FT–mVenus at 10 LD (b), 11 LD (c), 12 LD (d) and 13 LD (e) and gFD::mScarlet1–FD at 10 LD (f), 11 LD (g), 12 LD (h) and 13 LD (i). Insets in h,i show higher magnification of the outlined regions. j,k, Nuclear concentration of FD (j) and FT (k). Nuclear concentration was calculated as the total pixel intensity within a segmented nucleus divided by its area. Measurements were normalized by the maximum FD and FT concentrations among all analysed meristems. Small dots represent FD and FT concentrations in individual nuclei. Large circles denote the median concentration of FD or FT for each SAM at a given time point. Medians were compared across time points (n = 3, 4, 4 and 4 for 10 LD, 11 LD, 12 LD and 13 LD, respectively). Error bars represent the interquartile range for the previous median distribution. Statistical differences in median nuclear concentration between 10 LD and 11 LD, 12 LD, or 13 LD were assessed using the Brunner–Munzel test (α = 0.1), a non-parametric test for median comparison that is robust to small sample sizes, with two-sided pairwise comparisons. CZ, central zone; OC, organizing centre; PZ, peripheral zone; RM, rib meristem. l–o, Confocal images of SAM cells expressing gFT::FT–Venus–Halo–Venus; Col-0 at 12 LD (l), 13 LD (m), 14 LD (n) and 15 LD (o). Arrows in e,n,o indicate FT fluorescent protein signal. b–e,l–o, Cell walls (blue) were stained with Renaissance 2200. b–i,l–o, Scale bars, 20 μm. Confocal images in b–i,l–o are representative of three independent meristems. *P < 0.05; NS, not significant (P ≥ 0.05).