Diversity of Arbuscular Mycorrhizal Fungal Species in Soils of Cultivated Soybean Fields

Abstract

Mycorrhizae are presumably important contributors to plant growth in most ecosystems. Our objective in this study was to evaluate the population diversity of arbuscular mycorrhizal (AM) fungi in Clarion (well drained) and Webster (poorly drained) soils of four Iowa soybean [Glycine max (L.) Merr.] fi elds. Th ese soils normally occur together on the landscape, with Clarion in the upland and Webster in lowland positions. Previous work consistently has shown higher AM fungal spore counts in Webster soils. Spore morphology was used for the characterization of fungal species. Identifi cation of certain species was confi rmed using polymerase chain reaction (PCR)-based rDNA fi ngerprinting . Glomus claroideum, G. etunicatum, G. mosseae, G. viscosum, and Paraglomus occultum-like spores were prevalent in both Clarion and Webster soils. Trap cultures led to detection of several addi- tional AM fungal species, including G. clarum, G. coronatum, G. fasciculatum, G. vesiforme, Acaulospora calossica, and Entrophospora infr equens. Th e richness of the Glomus species varied from eight species in Webster soil of a fi eld with highest available P (203 mg kg −1 soil Bray P1), where spores of G. mosseae constituted 90% of the spore population, to 12 species in Clarion soil, with lowest available P (14 mg kg −1 soil Bray P1). Th e variability of AM fungal density and distribution was also high among samples taken only 2 m apart. Although diverse within the genus, this study showed the dominance of Glomus species in fi eld soils used to produce two important commercial crops, corn (Zea mays L.) and soybean, in the midwestern United States.

Arbuscular mycorrhizal fungal diversity in perennial pastures; responses to long-term lime application

“…Soil management practices and environment conditions may influence the diversity of AMF (Bhadalung et al 2005;Troeh and Loynachan 2009). The diversity of AMF communities tends to decrease when the intensity of agricultural inputs increases (Oehl et al 2010).…”

A new family, Pervetustaceae with a new genus, Pervetustus, and P. simplex sp. nov. (Paraglomerales), and a new genus, Innospora with I. majewskii comb. nov. (Paraglomeraceae) in the Glomeromycotina

“…Centrosema macrocarpum y Leucaena leucocephala, permitió aumentar el número de esporas recolectadas (Figuras 16 y 17), en comparación con el suelo proveniente del campo, donde no se pudieron recolectar esporas nucleadas (Tabla 4). Esto coincide con lo comunicado por Troeh y Loynachan (2009), quienes utilizando cultivos hospederos de HMA observaron no solo aumentos en la abundancia de esporas, sino también aumentos en la colonización por HMA. Asi como mencionan dichos autores, es probable entonces que los propágulos micorrícicos de los suelos utilizados en este estudio consistieran en segmentos de hifas y raíces colonizadas, más que en esporas.…”