Influence of NaCl on Brachiaria humidicola inoculated or not with Glomus etunicatum A.C.E.S. Mergulhão * 1 , H.A. Burity 1 , J.N. Tabosa 1 , M.V.B. Figueiredo 2 , L.C. Maia 3 1 Empresa Pernambucana de Pesquisa Agropecuária-IPA, CP 1022, CEP: 5076-000 Recife-PE, Brasil. 2 Embrapa-EPEAL, Macéio-AL, Brasil. 3 UFPE, Departamento de Micología, Recife-PE, Brasil adalia@ipa.br SUMMARY An experiment was carried out to investigate the effects of different levels of NaCl on the growth of the grass Brachiaria humidicola inoculated or not with the arbuscular mycorrhizal fungus (AMF) Glomus etunica- tum. The concentrations of NaCl utilized were 0, 0.22, 1.09, 1.96 and 2.84 g kg –1 of soil; corresponding to elec- trical conductivities of 2.22, 4.00, 8.13, 12.53 and 16.50 dS m –1. The salinity ratio of the soil reduced the dry matter in different parts of the plant when the electrical conductivity was above 8 dS m –1. Leaf area ratio and succulence increased at high salinity levels of the soil. The percentage of root colonization and the number of AMF spores in the rhizosphere were not affected by the increasing doses of NaCl added to the soil. Key words: mycorrhiza, stress, inoculation, salinity. INTRODUCTION The ability of mycorrhizal plants to tolerate adverse environmental conditions is of great value in verifying the behaviour of these plants when subjected to salt stress. Seve- ral investigations have shown that some arbuscular mycorrhizal fungi (AMF) can increase the nutrient absorption and production of biomass in plants grown in saline soils (Hirrel and Gerdemann, 1980; Ojala et al., 1983). AMF have improved the osmoregulation in co- lonized plants through the increase in the concentration of soluble substances in leaf tis- sue (Augé and Stodola, 1990). The introduction of AMF in saline soils could potentially Invest. Agr.: Prod. Prot. Veg. Vol. 17 (2), 2002 * Autor para correspondencia Recibido: 16-4-01 Aceptado para su publicación: 15-2-02