Fig. 7. Ultrastructure of Garland cells in wild type and in rbo^ts mutants. (A) Transmission electron microscopy (TEM) images of wild-type and rbo^ts Garland cells at 25°C. The cortical cell region extends 3 µm, with many labyrinthine channels (thin black arrows). Numerous vacuoles (a), longitudinal (white arrows) and transverse (thick black arrows) tubular elements, and coated vesicles and/or pits (arrowheads) are present in all section planes. Many sections also contain mitochondria (M) and β vacuoles (b). Wild type and rbo^ts appear indistinguishable at 25°C. (B) Following 10 minutes at 37°C, the number of vacuoles in rbo^ts cells is reduced, with remnant vacuoles being larger and more irregular. Labyrinthine channels swell and distend with many vacuolar structures (^*). Scale bar: 1 µm. (C) Higher-magnification images at 37°C. In rbo^ts, very elongated labyrinthine channels extend into the cell; these channels contain many vacuolar structures (^*). Thin black arrows show the origin of the labyrinthine channels at the basement membrane. Scale bar: 250 nm.