Ultrastructural Observations on Endogonaceae (Zygomycetes). II. Glaziellales Ord. Nov. and Glaziellaceae Fam. Nov.: New Taxa Based Upon Light and Electron Microscopic Observations of Glaziella A Urantiaca

ABSTRACT

Sporocarpic tissues of Glaziella aurantiaca were examined with light and electron microscopy in order to gain information on the possible teleomorphic nature of the fungus. The results from light microscopic studies indicate that the spores, which were presumed to be chlamydospores by earlier investigators, are actually ascospores that develop in unispored asci. The asci arise in locules from pockets of pseudoparenchyma within the thin walls of the sporocarps. Plasmogamy is presumably by hyphal conjugation. The sporocarpic hyphae are regularly septate and the septa are quite typical of ascomycetes, with electron-opaque material plugging a central pore and one or more associated Woronin bodies. The spore wall has a thick inner and thin outer wall, separated by a relatively complex zone of transition. Both walls are of a uniform granular consistency at the EM level. The outer wall is, in part, fused to the surrounding hyphae of the sporocarp. The spore cytoplasm has abundant glycogen deposits interspersed with lipid globules. Silver proteinate and barium permanganate post-staining observations were made on hyphae, septa, spore walls and cytoplasm. A new order, the Glaziellales, and a new family, the Glaziellaceae, are proposed for Glaziella aurantiaca, since it cannot be comfortably accommodated in any existing order of fungi. Its possible relationships to other fungi and possible mycorrhizal status are discussed.

Key Words:

• Endogonaceae
• Ascomycetes
• unispored asci
• mycorrhizal fungi
• septum
• spore ontogeny
• spore wall
• cytochemistry