Figure 4.

Transmission electron micrographs of developing epidermal cells of wild-type and ttg1-1seeds. A, Wild-type seed at 7 DAP. The cytoplasm is drawn into the center of the cell in a sharply defined column above the vacuole. Note large amyloplasts. B, ttg1-1 seed at 7 DAP. The cytoplasm is in the center of the cell over the vacuole. Some strands of mucilage are apparent between the cytoplasm and the outer tangential cell wall. C, Wild-type seed at 10 DAP. The cytoplasm is found in a narrower column over a much-reduced vacuole and both are surrounded by secondary cell wall. The outer tangential cell wall has ruptured and is no longer visible. D, ttg1-1 seed at 10 DAP. Similar to 7 DAP (B), the cytoplasm is found over a large vacuole. Some secondary cell wall is apparent over the cytoplasm in a low dome, bounded on both sides by fibrillar mucilage. The outer tangential cell wall is intact. a, Amyloplast; c, cytoplasm; m, mucilage; ow, outer tangential cell wall; sw, secondary cell wall; v, vacuole. Scale bars = 5 μm.