Abstract

Vachellia nilotica, a multipurpose tree useful to rural populations, is often used to rehabilitate Senegalese salt-affected soils due to its salt-tolerance probably related to arbuscular mycorrhizal fungi (AMF) symbiosis. This work aimed to determine the AMF communities associated with V. nilotica rhizosphere in salt-affected soils and their potential infectivity. Soils were sampled from six sites in the central region of Senegal. Soil chemical properties and total fungal communities were analyzed. Spores number was estimated and morphotypes were identified. Soil-borne AMF were trapped using V. nilotica plants to analyze their infectivity potential and their effect on plant growth and biomass production. Results showed the capacity of V. nilotica to grow in a heterogeneity of soils and revealed that rhizospheric soils are rich in AMF infectives strains. Data showed that salinity was the main factor that influenced the fungal structure and has a negative effect on AMF development, hence the highest number of spores in high salinities soils. This negative effect is greater in soils collected in dry season than in wet season. The highest density of spores was found in soils beneath the canopy, indicating the influence of plant rhizosphere on AMF diversity. Morphotypes identified are related to the genus Glomus, Gigaspora, Acaulospora. AMFs in these soils can establish a good mycorrhization with V. nilotica and increase plant biomass and height.

Key words: Vachellia nilotica, arbuscular mycorrhizal fungi, diversity, salt affected soils, rhizosphere, infectivity.