Anatomical structures of stems of the wild type (WT), 35S:MIR857, and the mir857 mutant. A to L, Cross sections of 6-week-old stems of wild-type, 35S:MIR857, and mir857 mutant plants. co, Cortex; ph, phloem; xy, xylem. Scale bar = 100 μm (A, E, and I), and 50 μm (B–D, F–H, and J–L). The area within the red-yellow circles corresponds to the region containing sclerenchyma cells in A, E, and I. M, Sclerenchyma development was impaired in 35S:MIR857 and mir857 plants. The definition of the ratio was used to evaluate the development of sclerenchyma. The ratios of the different genotypes are plotted. Data represent means ± sd (n = 10). *, 0.01 < P < 0.05. N, Xylem cell numbers in single vascular bundles of inflorescence stems. Data represent means ± sd (n = 15).