Fig. 9. Stereopairs of 0.20 µm thick sections of gea1-4 mutant cells incubated at 37°C for 40 minutes. (A) A curved tubular network structure (arrow) is connected to an ER sheet (ER; top-left). The central portion consists of a network of wide-meshed, lightly-stained tubules, and at the periphery, larger and more intensely stained tubules display nodules (arrowhead) adjacent to secretion granules (SG). Magnification x73,500. (B) A large tubular network (arrow) with small dilations at the intersections of polygonal meshes (arrowheads) forms a spherical mass and is connected to an ER ribbon continuous with a sheet of subplasmalemmal ER (ER). N, nucleus. Magnification x74,500. (C) Tubular networks form ring-like structures (arrows). Wide polygonal meshes are clearly visible in the upper structure, seen in oblique view. Below, fenestrated and tubular structures seen in profile form two concentric rings. SG, secretion granule. Magnification x87,500. (D) A large, relatively flattened tubular network consists of lightly-stained, wide polygonal meshes (arrow) with a few small dilations (arrowhead). SG, secretion granule; V, vacuole. Magnification x70,500. (E) A tubular network (arrow, top-left) with darkly stained dilations (arrowhead) forms a ring in proximity to the nuclear envelope. At the bottom-right another tubular network forms a large ovoid mass (arrow). Two ER sheets in continuity with the nuclear envelope are labeled ER. N, nucleus. Magnification x82,300.