Abstract

A pot experiment was set to examine the effects of arbuscular mycorrhizal fungi (AMF) on mineral nutrition of a tropical legume tree (Acacia senegal) under three different water status. Acacia senegal seedlings were inoculated with three species of AMF, Glomus intraradices, Glomus fasciculatum or Glomus mosseae. Three water levels (field capacity, moderate water deficiency and severe water deficiency) were applied to the pots after transplantation. A. senegal seedlings were colonized by the three AM fungi. Twelve weeks after water stress imposition, uptake nutrient of A. Senegal was enhanced by mycorrhizal inoculation under moderate and severe water status. Root colonization varied from 30.4 to 62.5%. The lowest intensity (30.4%) was observed on field capacity associated with G. intraradices and the highest root colonization (62.5%) was observed on severe water deficiency associated with G. fasciculatum. Relative improvement was noted in the foliar nutrient content nitrogen (N), phosphorus (P), potassium (K) and shoot water content of the inoculated plants, whatever the water regime. Mycorrhizal inoculation has no significant effect on shoot calcium (Ca), magnesium (Mg) and sodium (Na) compared to uninoculated plants. G. fasciculatum was the most efficiency fungus in nutrient foliar of A. senegal plants under water defiency conditions. Inoculating A. senegal plant with the arbuscular mycorrhizal fungus G. fasciculatum increased ability to acquire N, P, and K under water deficiency conditions.

Key words: Arbuscular mycorrhizal fungi, Acacia senegal, mineral nutrient, water deficiency.