Changes in Land Use System and Environmental Factors Affect Arbuscular Mycorrhizal Fungal Density and Diversity, and Enzyme Activities in Rhizospheric Soils of Acacia senegal (L.) Willd.

Abstract

The responses of the soil microbial community features associated to the legume tree Acacia senegal (L.) Willd. including both arbuscular mycorrhizal fungal (AMF) diversity and soil bacterial functions, were investigated under contrasting environmental conditions. Soil samples were collected during dry and rainy seasons in two contrasting rainfall sites of Senegal (Dahra and Goudiry, in arid and semiarid zone, resp.). Soils were taken from the rhizosphere of A. senegal both in plantation and natural stands in comparison to bulk soil. A multiple analysis revealed positive correlations between soil physicochemical properties, mycorrhizal potential and enzyme activities variables. The positive effects of A. senegal trees on soil mycorrhizal potential and enzyme activities indicates that in sahelian regions, AMF spore density and diversity as well as soil microbial functions can be influenced by landuse systems (plantation versus natural population of A. senegal) and environmental conditions such as moisture and soil nutrient contents. Our study underlines the importance of prior natural AMF screening for better combinations of A. senegal seedlings with AMF species to achieve optimum plant growth improvement, and for restoration and reforestation of degraded lands.

Arbuscular mycorrhizal fungi (AMF) communities associated with cowpea in two ecological site conditions in Senegal

“…These results confirmed the ability of the primer AML2 to amplify several groups of AMF and indicated a wide diversity of AMF in roots of cowpea (Lee et al, 2008). However, these findings were opposed to those of Manga et al (2007) and Ndoye et al (2012) who found only species of the genus Glomus in rhizosphere of Acacia senegal in the semi-arid zone of Bambey and Dahra (Senegal), respectively. Nevertheless, Ngonkeu (2009) using the same fungal primers as the previous authors (LR1, FLR4), had already found some Gigasporaceae and Acaulosporaceae species in the roots of corn in Cameroon.…”

“…Nevertheless, Ngonkeu (2009) using the same fungal primers as the previous authors (LR1, FLR4), had already found some Gigasporaceae and Acaulosporaceae species in the roots of corn in Cameroon. These results might be explained by a selective mycorrhization (Helgason et al, 2002) in acacia trees because other species of fungi were found in their root zone particularly in Acacia senegal (Ndoye et al, 2012). The genus Glomus is the most diverse in our study with six species, representing 40% of all the species found in roots of cowpea.…”

“…However, a study conducted in Benin showed an equal distribution between Glomus and Scutellospora species in a woodland of Isoberlina doka (Houngnandan et al, 2009). This AMF diversity described in Benin is low as compared to that found in the reserve of Bandia in Senegal (Sene et al, 2012) and those in the arid and semi-arid areas of Africa and elsewhere (Bâ et al, 1996;Mohammad et al, 2003;Bouamri et al, 2006;Ndoye et al, 2012;Kachkouch et al, 2012). In Senegal, molecular diversity studies of AMF performed on acacia trees showed only the presence of Glomus in their roots, suggesting a preferential mycorrhization of these trees because other genera have been isolated in their rhizosphere (Manga et al, 2007;Ndoye et al, 2012).…”

“…Most of them showed the predominance of the genus Glomus in several ecosystems, particularly in Senegal (Diop et al, 1994;Manga et al, 2007;Ndoye et al, 2012), Burkina Faso (Bâ et al, 1996) and Morocco (Abbas et al, 2006;Bouamri et al, 2006). However, a study conducted in Benin showed an equal distribution between Glomus and Scutellospora species in a woodland of Isoberlina doka (Houngnandan et al, 2009).…”

Diversity and abundance of arbuscular mycorrhizal fungi associated with acacia trees from different land use systems in Ethiopia

“…In a study with Acacia senegal in the sahelian regions of Senegal, Ndoye et al (2012) found that the positive effects of this plant species on AMF spore density and diversity as well as on soil microbial functions can be influenced by land-use systems (plantations versus natural populations of A. senegal). In tropical dry ecosystems of Mexico, Gavito et al (2008) found higher AMF morphospecies richness in primary forests than in secondary forests and pastures.…”