Hyphal structure in Fusarium oxysporum (Schlecht) revealed by freeze-etching

Summary Freeze-etched hyphae of F. oxysporum exhibited a single layered cell wall; a plasmalemma, in which invaginations were frequently associated with paramural vesicles; cytoplasma bearing lipid droplets, vacuoles, intravacuolar vesicles and nuclei with typical nuclear pores. Some hyphae bore crystalline inclusions characterized by a pronounced hexagonal, external ornamentation and it is suggested that the presence of these crystals and intravacuolar vesicles are indicative of aging hyphae.