Fig. S2 Tomographic slice images of the vacuolar reticulum (VR) in the subapical
cytoplasm of rhizoids. The VR forms branched polymorphic networks that extend parallel
to the longitudinal cell axis (indicated by large arrows pointing towards the rhizoid tip).
The small arrows point to ring-like structures encircling tubular connections between two
segments (a). Internal luminal vesicles (IV) are clearly detectable in single tomographic
slices (a, b). The VR has striking ultrastructural similarities with multivesicular bodies (c;
MVB; conventional electron micrograph) that were observed in large number in the
subapical cytoplasm. ER endoplasmic reticulum; G Golgi stack; MV microvesicle. Bars:
500 nm (a, b), 100 nm (c)