Two major types of arbuscular mycorrhizal associations, the Arum-type and the Paris-type were recognized by Gallaud in 1905 based on structural features of the colonization process. Although the Paris-type is the most common (Smith and Smith, 1997), the majority of research concerning structure/function of arbuscular mycorrhizas has involved the Arum-type because of its prevalence among important crop species. Recently, we have studied the Paris-type arbuscular mycorrhiza association in Panax quinquefolius (ginseng). In particular, we have examined the interface between the cytoplasm of root cells and the extensive hyphal coils and the arbuscules that develop from them (arbusculate coils) using various affinity methods combined with TEM. Also, we have determined the effect of hyphal coils and arbusculate coils on the cytoskeleton of ginseng root cells using immunofluorescence techniques combined with laser scanning confocal microscopy. The results of these studies will be compared with published work by ourselves and others (particularly research by P. Bonfante and M. Harrison) on the interface and changes in cytoskeleton in Arum-type mycorrhizas. The structural features will be discussed in terms of functioning of these two major types of arbuscular mycorrhizas.

Key words: arbuscular mycorrhiza, Arum-type, cytoskeleton, interface, Paris-type, structure