Distribution of two ericoid mycorrhizae in a New Jersey Pine Barrens upland-wetland site and the effect of mycorrhizal presence on ericaceous plants

Though studies continue to reveal other possible ericoid endophytes with mycorrhizal capabilities, two well-known ericoids, Rhizoscyphus ericae and Oidiodendron spp., are the most widely accepted and studied ericoids associated with Ericaceae in the Northern Hemisphere. In researchers’ efforts to identify the true nature of ericoid mycorrhizae, many studies focus on the infective capabilities, morphological features, phylogenetic relationships, and specific ecological roles of these two fungi; however, knowledge pertaining to the distribution of particular ericoid species is very limited. In addition, many significant findings are based solely on a single strain of Rhizoscyphus ericae. Though distribution patterns of a single fungal species can be partially deduced from available literature, few published studies focus primarily on examining the distribution patterns of these ericoid mycorrhizae in the field, particularly in relation to each other. In an effort to add to the broader understanding of ericoid mycorrhizae, this project focuses on the association and distribution of both aforementioned fungi in the New Jersey pine barrens. Initial interest in this research was generated by preliminary findings, which revealed a possible dominance of fungal root assemblages by Oidiodendron spp in comparison to the more widely-studied Rhizoscyphus ericae (unpublished data). It seemed that Oidiodendron was extracted from wild and cultivated Ericaceae roots more often (unpublished data). In an effort to further analyze this observation, a variety of ericaceous plant species and their fungal symbionts were examined in two growth chamber experiments and one field survey. When both fungal species of interest were inoculated with two different plant species under aseptic conditions, culturing methods revealed a higher incidence of Oidiodendron spp. extracted from Vaccinium corymbosum (Oidiodendron extracted from 24% of roots; Rhizoscyphus ericae extracted from < 1% of roots) and from Arctostaphyluos uva ursi (Oidiodendron extracted from 27% of roots; Rhizoscyphus ericae extracted from 1% of roots). Though dominance patterns were inconclusive in the native soil growth chamber experiment, culturing methods from field-extracted plant roots also revealed a higher incidence of Oidiodendron, this time in association with Gaylussacia baccata (92% colonized by Oidiodendron vs. 8% by Rhizoscyphus ericae) and Gaultheria procumbens roots (80% colonized by Oidiodendron vs. 6% by Rhizoscyphus ericae) in an upland-wetland field site. In the above scenarios, both fungi were extracted from all plant species studied, but Oidiodendron was extracted more frequently, supporting a possible dominance of fungal root assemblages by Oidiodendron spp. in this New Jersey locale when compared to Rhizoscyphus ericae. Also revealed in this study were differences in colonization patterns of fungi dependent upon habitat type. Most notable was the higher colonization of roots by fungi in the wetlands on both plant species surveyed along an upland-wetland gradient. Other significant findings, not related to distribution patterns, are discussed in further detail in subsequent chapters.M.S.Includes bibliographical referencesby Rebecca Jane Bachele