Functional Diversity of Mycorrhizal Fungi Has Differential Effects on Salinity Tolerance of <i>Acacia seyal</i> (Del.) Seedlings

Acacia seyal is a leguminous plant that plays an important role in the ecosystem of Sahelianzone by producing gum, wood and fodder. The growth of A. seyal is subject to many constraints as salinity which canaffect the development of this tree. Therefore, soil microorganisms can help A. seyal to better tolerate the effectsof negative environmental stresses. The contribution of arbuscular mycorrhizalfungi (AMF) to the salt tolerance of A.seyal, was evaluated by testing the effects of eight different arbuscularmycorrhizal fungi (AMF) isolates in the performance of A. seyal seedlings subjected to different levels of salinity (0,340 and 680 mM). The results based on growth parameters of shoot and rootparts, shoot mineral N, P, K and Na content as well as survival rates and mycorrhizationshowed that AMF improved mineral nutrition of A. seyal seedlings during salt stress. The combination between AMFand salinity provided evidence that the efficiency of AMF isolates werevariable in improving mineral nutrition and mortality rate for A. seyal seedlings related to the levelof salt stress. However, the effects of inoculation were variable depending tothe AMF isolate associated with seedlings and the level of salinity, suggestingthat interactions between plants and AMF can be modulated by both AMF diversityand the type and level of abiotic factors. Rhizophagusintraradices was more efficient at 680 mM NaCl in plant growth and mineraluptake while Glomus deserticola didnot promote a better plant development than most of the other speciesinoculated to seedlings.