Strong correlations among PP TC development and abundance of miR156, miR172, and SPLs. A, C, and E, PP TC development across shoot maturation (A), leaf maturation of juvenile leaf 1 and adult leaf 11 (C), and basipetal maturation in adult leaf 11 (E). B, D, and F, RT-qPCR analysis of transcripts isolated from leaves at the same developmental stages as leaves subjected to mPS-PI staining and PP TC analysis as shown in A, C, and E, accordingly. Relative abundance levels were set to 1 for: miR156 in juvenile leaves and miR172, SPL3, SPL9, SPL10, and SPL15 in adult leaves (B); miR156, SPL10, and SPL15 in 11-d-old leaf 1, miR172, and SPL3 in 35-d-old adult leaf 11, and SPL9 in 23-d-old adult leaf 11 (D); and miR156, miR172, SPL3, SPL9, SPL10, and SPL15 in apical regions of adult leaf 11 (F). Data are mean ± se across at least five biological replicates for A, B, C, E, and F, and three biological replicates for D. juv, juvenile; ad, adult.