Successive pot cultures reveal high species richness of arbuscular endomycorrhizal fungi in arid ecosystems

Abstract

Three cycles of successive trap cultures were utilized to determine the taxonomic structure of arbuscular fungi associated with mesquite (Prosopis spp.) from three locations in the Sonoran desertscrub biotic community and one location in the Chihuahuan desertscrub biotic community. Unlike the low species richness found in previous studies of some arid habitats, seven to nine species were recovered from each sampling site. This number is comparable to that found in many other plant communities. Seventy-five percent of the species found after three culture cycles were not detected in the first trap cultures, suggesting that a high proportion of arbuscular fungi in arid habitats may be nonsporulating in the field. Low colonization levels may account for the absence of sporulation, but ecological factors such as moisture limitations also may be involved. Although a total of 10 different species was detected, generic richness was limited, with 9 of these species in Glomus and 1 in Entrophospora. As long as measurement of species richness is based on occurrence of sporulation, successive trap cultures provide a means of detecting nonsporulating mycorrhizal colonizers in arid and other habitats. Keywords: vesicular – arbuscular mycorrhizae, ecology, desert, Glomales.

Assessment of VA mycorrhizal inoculum potential in relation to the establishment of cactus seedlings under mesquite nurse-trees in the Sonoran Desert

“…As suggested by Stutz and Morton (1996), the low levels of sporulation reported in other desert soil surveys (Rose, 1981;Pond et al, 1984;Cui and Nobel, 1992), as well as their own detection of many non-sporulating VAM fungal species, indicate that lack of sporulation is a common if not predominant phenomenon in some arid regions. This makes it initially difficult to evaluate species diversity in any particular study.…”

“…was found in two samples, only in the UC soils. The difficulty in increasing spore populations from native soils with low or non-sporulating endophyte populations is not uncommon, and may require multiple, successive trap-culture cycles to detect species diversity (Stutz and Morton, 1996).…”

Estabelecimento e capacidade infectiva de Gigaspora margarita e Glomus clarum em solo sob erosão

“…Esta espécie não produziu esporos no experimento 1, como também não foram detectados esporos no material original. No entanto, sabe-se que cultivos sucessivos ou mais prolongados favorecem a esporulação de número maior de espécies, especialmente as mais raras (Stutz & Morton 1996). Há vários relatos de ocolTência de A. appendicula em ecossistemas brasileiros (Fernandes & Siqueira 1989;Siqueira et aI.…”

Occurrence of arbuscular mycorrhizal fungi in soils of early stages of a secondary succession of Atlantic Forest in South Brazil

“…Conversely, results of van der Heijden et al (1998) on the relation between AMF and plant diversity were not observed in this study. However, we recognize that our measurement of AMF diversity probably does not represent the entire fungal community as it does not account for cryptic non-sporulating species colonizing plant roots (Stutz & Morton 1996).…”