The influence of arbuscular mycorrhizal fungi (AMF) and rock phosphate (RP) was studied on Acacia gummifera, an endemic and Moroccan spontaneous species that is experiencing a regression. They are also a source of firewood, charcoal and precious air fodder in the dry season. The response of Acacia gummifera to a mixture of two species of arbuscular mycorrhizal fungi (Glomus intrardices and Glomus mossae) and two levels of rock phosphate (9 and 37 % of P equivalent of 0,25 and 0,5g P/kg of soil) was evaluated under greenhouse conditions.
The arbuscular mycorrhizal root colonization varied from 10 % to 25 % when rock phosphate applications increased. Acacia seedlings grew poorly without arbuscular mycorrhizal fungi and without rock phosphate applications. However, AMF plants with RP applications achieved better results in terms of P and N concentration in shoot and root. In contrast, there were not additive effects of inoculation and phosphate application on total biomass. However, inoculation of acacias took up more P and N at 0.25 g P kg-1 of soil and above. These results suggest that AMF are able to absorb P from soil and rock phosphate for a better mineral nutrition of Acacia gummifera.