Figure 1.

Cross sections of wild-type and irx5-1 stems. Sections of wild type (A, C, E, and G) and irx5-1 (B, D, F, and H) were stained with Toluidine blue. xe, xylem elements; if, interfascicular cells. Arrowheads indicate irregular cell walls. (Bars in A–D represent 0.05 mm. Bars in E–H represent 0.01 mm.)