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

Abstract

Acacia seyal is a leguminous plant that plays an important role in the ecosys-tem of Sahelian zone by producing gum, wood and fodder. The growth of A. seyal is subject to many constraints as salinity which can affect the develop-ment of this tree. Therefore, soil microorganisms can help A. seyal to better tolerate the effects of negative environmental stresses. The contribution of arbuscular mycorrhizal fungi (AMF) to the salt tolerance of A. seyal, was eva-luated by testing the effects of eight different arbuscular mycorrhizal 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 parame-ters of shoot and root parts, shoot mineral N, P, K and Na content as well as survival rates and mycorrhization showed that AMF improved mineral nutri-tion of A. seyal seedlings during salt stress. The combination between AMF and salinity provided evidence that the efficiency of AMF isolates were varia-ble in improving mineral nutrition and mortality rate for A. seyal seedlings related to the level of salt stress. However, the effects of inoculation were va-riable depending to the AMF isolate associated with seedlings and the level of salinity, suggesting that interactions between plants and AMF can be mod-ulated by both AMF diversity and the type and level of abiotic factors. Rhizo-phagus intraradices was more efficient at 680 mM NaCl in plant growth and mineral uptake while Glomus deserticola did not promote a better plant de-velopment than most of the other species inoculated to seedlings.