Figure 8
Transmission electron micrographs of tobacco zygotes and proembryos. (A) Ultrathin section of a zygote at 84 h after pollination. The plastids, vesicles and lipid bodies are highlighted with adjacent arrows. Bar = 3 μm. (B) The two-celled proembryo with an apical cell and a basal cell. Bar = 3 μm. (C) The local amplification of figure B shows plasma membrane and cell wall between apical and basal cells. Some endocytic vesicles localize in cell plate and are highlighted with arrows. Bar = 1 μm. (D) Cytoplasm in a proembryos in vivo. The plastids, mitochondria and rough-endoplasmic reticulum are highlighted with adjacent arrows. Bar = 1 μm. (E) Cytoplasm in a proembryos in vivo. Bar = 500 nm. (F-I) Ultrathin section images of 50 μM β-GlcY treated proembryos. After treatment with β-GlcY, the localization of endocytic vesicles in cell plates is affected (F and G). The distribution and morphology of cell organelles in β-GlcY treated proembryos are also changed (H and I). Bars = 500 nm in (F); 200 nm in (G, H and I). (J-L) Ultrathin section of in vitro cultured proembryo without β-GlcY treatment. Some endocytic vesicles localize in cell plate and the pattern is similar with in vivo proembryos. Bars = 500 nm in (J); 200 nm in (K and L). AC, apical cell; BC, basal cell; CW, cell wall; rER, rough-endoplasmic reticulum; L, lipid body; M, mitochondrion; N, nucleus; P, plastid; EV, endocytic vesicle.