| Abstract: | Microtubular elements in the chloroplasts (chl-MTs) of Oedogonium capilliforme Wittrock were examined by conventional electron microscopy and immunoelectron microscopy. Chl-MTs were frequently seen in the terminal, convex, and concave peripheral regions of the chloroplasts. Each bundle of chl-MTs was composed of 2–25 tubular elements. Some chl-MTs were located in the stroma. Chl-MTs frequently bridged two areas of the envelope membrane near the apex of convex regions of chloroplasts. Some chl-MTs were closely associated with the envelope membrane via apparent anchors along their length. The distribution patterns of chl-MTs and their appearance suggest that chl-MTs are involved in the maintenance of the outer shape of chloroplasts. However, immunoelectron microscopy with an antibody against α-tubulin indicated that the chl-MTs are not composed of tubulin. |
