Fig. 2. Defects in ale1 mutants in cuticle formation and adhesion of the endosperm to the embryo’s surface. (A-E,K,M) Sections of wild-type seeds. (F-J,L,N) ale1-1 seeds. At each stage, seeds were sectioned and observed by light microscopy (A-J) or transmission electron microscopy (K-N). (A,F) Early heart-stage embryos. (B and G) Torpedo-stage embryos. (C,H) Magnified views of the boxed areas in B and G, respectively. (D,I) Walking-stick stage embryos. (E,J) Magnified views of the boxed areas in D and I, respectively. Arrows indicate adaxial surfaces of cotyledons. (K,L) Surfaces of embryos at the 16- to 32-cell embryo proper stage. The arrowheads indicate the thin electron-dense layer in the outermost region of the epidermal cell walls of the embryo. (M,N) Surfaces of heart-stage embryos. A continuous densely stained cuticle covered the entire wild-type embryo (M). The cuticle on the surface of the ale1-1 embryo was discontinuous (N; the arrowheads indicates the margin of the densely stained cuticle). em, embryo; en, endosperm; c, cuticle; cw, cell wall. Scale bars: 20 µm (A,B,F,G); 10 µm (C,E,H,J); 50 µm (D,I); 200 nm (K,L); and 500 nm (M,N).
