Fig. 2. KANADI loss-of-function anatomical phenotypes. (A,B) Longitudinal and transverse sections of 12-day-old wild-type seedlings demonstrate that young leaf primordia exhibit polarity along the ab/ad axis immediately after their separation from the shoot apical meristem. Polarity is evident both by their crescent shape and the appearance of vacuolated cells (arrows) on the abaxial side first (B). (C) In differentiating leaves, asymmetric anatomy along the ab/ad axis is evident in the shape of the adaxial palisade mesophyll versus the abaxial spongy mesophyll. Anticlinal cell divisions characterize the L1 and L2 cell layers both adaxially and abaxially (insert; arrow). (D,E) In contrast, leaf primordia of kan1-2 kan2-1 12-day-old seedlings appear radial (arrows), with all cells maintaining their densely cytoplasmic appearance for a prolonged period. (F) Many more cell layers are found in differentiating leaves, resulting from abnormal periclinal divisions at the abaxial side (insert; arrows). (G-I) Leaf primordia of kan1-2 kan2-1 kan3-1 seedlings (G,H) are also radial at inception (arrows), but do exhibit some asymmetric growth later in development such that the leaves are also thicker than those of wild type (I). The transverse sections of the leaves in C, F, and I are from the proximal region of expanding leaves of 12-day-old seedlings. *, stipules; ab, abaxial; ad, adaxial; lp, leaf primordia; m, meristem; pm, palisade mesophyll; sm, spongy mesophyll. Scale bars: 50 µm.