Fig. 3.

SCL28 promotes plant organ growth and affects the activity of the meristem. (A) Root phenotype in 10 d-old wild-type (wt), scl28-3, and scl28-3 × ProSCL28:SCL28-VENUS plants. (Scale bar, 1 cm.) (B) Root growth of wild-type, scl28-3, and scl28-3 × ProSCL28:SCL28-VENUS plants. (C) Root-elongation rate (millimeters per hour) of wild-type, scl28-3, and scl28-3 × ProSCL28:SCL28-VENUS plants. Box plots with the measurements from 15 roots are shown. Different letters indicate significant differences (P < 0.05; ANOVA followed by Tukey’s multiple comparison test). (D) Root tip architecture of 6-d-old wild-type, scl28-3, and scl28-3 × ProSCL28:SCL28-VENUS plants examined by LSCM in PI (magenta)-stained plants. The white arrowheads mark the position of the QC and the end of the meristem where cells start to elongate. (Scale bar, 50 μm.) (E) Number of meristematic cortex cells (Nm) and meristematic zone length in wild-type, scl28-3, and scl28-3 × ProSCL28:SCL28-VENUS plants. Box plots with the measurements of 15 roots are shown. Different letters indicate significant differences (P < 0.05; ANOVA followed by Tukey’s multiple comparison test). (F) Detailed view of meristematic cortex cell files in wild-type and scl28-3 plants. (Scale bar, 10 μm.) (G) Average length of cortex cells in the root meristem in wild-type and scl28-3 plants. Box plots with the measurements of 10 cells from 20 roots of each genotype are shown. *P < 0.05 (significant differences from the wild type; Student’s t test). (H) Metaphasic cortex cells in the root meristem in wild-type and scl28-3 plants stained with PI (magenta) identified using the CYCB1;1-GFP (green) reporter. (I) Length of metaphasic cortex cells in the root meristem in wild-type and scl28-3 plants. Box plots with the measurements of at least 20 metaphasic cells found in at least 10 plants of each genotype are shown. *P < 0.05 (significant differences from the wild type; Student’s t test).