Figure 3.

Increased cambium in inflorescence stems of tkv mutant. A to F, Transverse sections through the apical end of the inflorescence stem (just below the youngest silique; A and B) and the basal end of the inflorescence stem (C, D, E, and F). A, C, E, tkv. B, D, F, Wild type. E and F are enlargements of a vascular bundle in C and D, respectively. Opaque cells inside of the phloem are cambial-like cells and possibly include xylem parenchyma cells. Arrowheads point to xylem, and arrows point to phloem. Scale bars in A, B, C, D, G, and H = 50 μm, and scale bars in E and F = 25 μm. G and H, Transverse sections through the primary root of week-old seedlings in the root elongation zone, where root hairs emerge. G, Wild type. H, tkv. Arrowheads point to xylem axes, and arrows point to phloem cells. Scale bars = 16 μm.