Fig. 1. Phenotypes of wild-type and brk2 mutant leaves. Cyanoacrylate glue impressions of the abaxial surfaces of wild-type (A) and brk2 (B) adult leaf blades. In A black arrowheads indicate stomata; in B black asterisk indicates an abnormal stomatal subsidiary cell. Toluidine-Blue-O-stained cross sections of wild-type (C) and brk2 (D) adult leaf blades. Thickenings in the outer epidermal cell wall at the junctions between adjacent epidermal cells are seen in wild type but not brk mutant leaves (black arrows). In both epidermal impressions and cross sections, the brk3 phenotype (not shown) is indistinguishable from that of brk2. Scale bars: 100 µm.