Fig. 3

TT16 and TT1 promote IAB deposition. a to m Fluorescence images of longitudinal sections of representative tt16 (a to f), tt1 (g to l) and wild type (m) ovules and seeds stained with auramine O (yellow). Seed cell walls are counterstained with calcofluor (cyan). n Position of detectable auramine O signal in wild type, tt16 and tt1 seeds along the distal-proximal (micropyle-chalaza) axis. The micropyle-chalaza axis was assimilated to a [0,1] segment (see methods). Error bars represent standard deviations, n > 10. o to v Transmission electron micrographs showing the IAB of tt16 and tt1 ovules (stage 3-VI) and seeds at globular embryo stage. Black arrows indicate the interface between endothelium and nucellus/endosperm. en, endothelium; nu, nucellus; es, endosperm. Ecotype Col. Scale bars: (a), (b), (g) and (h) 30 μm, (c) to (f) and (i) to (m) 50 μm, (s) 1 μm, (p), (s), (t), (u) and (v) 0,25 μm, (q) and (r) 0,5 μm