Figure 1.

Lignin location and amount differs during three stages of Arabidopsis stem development. A to C, Representative brightfield images, corresponding UV lignin autofluorescence (blue), and falsely colored heat map in stem cross-sections from stage 1 (A), stage 2 (B), and stage 3 (C). Scale bars = 50 µm. D and E, Quantification of corrected lignin UV autofluorescence from stem cross-sections for eight developmental timepoints. Cross-hatched bars indicate stage 1, solid gray bars indicate stage 2, and horizontal bars indicate stage 3. D, Corrected fluorescence for xylem vessel elements increases throughout development. E, Corrected lignin UV autofluorescence for fibers increases throughout development. A one-way ANOVA was used to compare developmental stages; n > 30 cells for each developmental stage from three biological replicates; lowercase letters indicate significantly different values according to Tukey-Kramer post-hoc tests (P < 0.0001). Bars ± se.