Structural characteristics of root-fungus associations in two mycoheterotrophic species, Allotropa virgata and Pleuricospora fimbriolata (Monotropoideae), from southwest Oregon, USA.

All members of the Monotropoideae (Ericaceae), including the species, Allotropa virgata and Pleuricospora fimbriolata, are mycoheterotrophs dependent on associated symbiotic fungi and autotrophic plants for their carbon needs. Although the fungal symbionts have been identified for A. virgata and P.

Ultrastructural localization of heavy metals in the extraradical mycelium and spores of the arbuscular mycorrhizal fungus Glomus intraradices.

Arbuscular mycorrhizal fungi, obligate symbionts of most plant species, are able to accumulate heavy metals, thereby, protecting plants from metal toxicity. In this study, the ultrastructural localization of Zn, Cu, and Cd in the extraradical mycelium and spores of the arbuscular mycorrhizal fungus Glomus intraradices grown in monoxenic cultures was investigated. Zinc, Cu, or Cd was applied to the extraradical mycelium to final concentrations of 7.

Pityopus californicus: structural characteristics of seed and seedling development in a myco-heterotrophic species.

Pityopus californicus (Eastw.) H. F.

Seasonal adaptations of the tuberous roots of Ranunculus asiaticus to desiccation and resurrection by changes in cell structure and protein content.

The annual developmental cycle of tuberous roots of Ranunculus asiaticus was studied with respect to structure and content of their cells, to understand how these roots are adapted to desiccation, high temperature and rehydration. Light microscopy, histochemical analysis, and protein analyses by SDS-PAGE were employed at eight stages of annual root development. During growth and maturation of the roots, cortical cells increased in size and their cell walls accumulated pectin materials in a distinct layer to the inside of the primary walls, with pits between adjoining cells.