Figure 1.

Two modes of rapid cell elongation in Arabidopsis roots. A, Distinct zones in the Arabidopsis root. Yellow, white, red, and blue outlines indicate cortical cells in the stem cell niche, the PM, the TZ, and the EDZ, respectively. A magnified image around the TZ is shown on the right. Bars = 50 µm. B, Cell length over the distinct zones of roots. Cortical cells were measured for cell numbers from the quiescent center (QC) and cell length. C, EdU incorporation around the TZ. Five-day-old roots were stained with EdU, and the cortical cell file was visualized by propidium iodide (PI) staining. Bar = 10 µm. D, Frequency of EdU incorporation into cortical cells. EdU signals were observed for the last PM cell, the first TZ cell, the last TZ cell, and the first EDZ cell. n > 41. E, Cortical cells around the TZ of 5-d-old wild-type (WT) and ccs52a1 roots. Bars = 50 µm. F, Cell number in the PM and the TZ of wild-type and ccs52a1 roots. Data are presented as means ± sd (n > 24). Significant differences from the wild type were determined by Student’s t test: *, P < 0.01.