Effect of Arbuscular Mycorrhizal Fungi on the Drought Tolerance of Sorghum Bicolor

In order to study the role of fam on water stress tolerance of sorghum plants. factorial experiment under greenhouse conditions was conducted with four levels of water potential (- 0.04, -0.2, -0.4 and -0.8 map) and two levels of phosphorus (0 and 25 mgkg^-1). the results demonstrate that there were no roots colonized with amf in non-inoculated plants. in inoculated plants roots colonized with amf percentage increased with increased of water stress and decreased with phosphorus addition and the higher value was 86% in plants grow under water potential -0.8 mpa and received 0 phosphorus while the lowest value was 46% in plants grow under water potential -0.04 mpa and received 25 phosphorus. inoculation with amf increased plant fresh weight, roots, shoots dry matter, and plant phosphorus uptake. the results show amf have protected sorghum plants against drought stress and it is clear that the effects of amf on plant growth parameters was higher than the effects of phosphorus addition specially in drought stress conditions hence we can suggested that there are addition ways than phosphorus nutrition improvement that amf can increase host plant drought tolerance.