Figure 2.

Cytokinin is sufficient to activate cambium prematurely, and this requires LBD3 and LBD4

(A) Cross-sections of 10-day-old wild-type (WT) and ipt1;3;5;7 roots.

(B) Cross-sections of 5-day-old WT roots. 3-day-old roots were treated for 2 days with mock or 1 μM BAP. Cells and area inside of dotted line were considered in cell file number (C) and total radial area quantifications (D), respectively.

(C and D) Quantification of cell file number (C) and total radial area (D) in the experiment presented in (B). Two-tailed t test. ^∗∗p < 0.01.

(E and F) Cross-sections of WT, lbd3, lbd4, and lbd3;4 in 8-day-old roots. Six-day-old roots were treated for 2 days with mock (E) or 1 μM BAP (F). Cells and area inside of dotted line were considered in cell file number (G) and total radial area quantifications (H), respectively.

(G and H) Quantification of cell file number (G) and total radial area (H) in the experiment presented in (E) and (F).

Sections were collected from the main roots 5 mm below the hypocotyl-root junction. Scale bars, 20 μm. Red dots indicate cell numbers or radial area in individual roots (C, D, G, and H). n, number of independent roots analyzed. A separate ANOVA test was performed for mock and BAP treatment. Different red letters indicate significant differences at level alpha = 0.05, as determined by a one-way ANOVA with Tamhane’s post-test. The exact p values for each comparison can be found in Data S2A–S2D. See also Figures S3A–S3E and Data S2A–S2D.