SALT STRESS RESPONSE OF SALT-SENSITIVE AND TOLERANT DURUM WHEAT CULTIVARS INOCULATED WITH MYCORRHIZAL FUNGI

Abstract

The effects of arbuscular mycorrhizal fungi (AMF) and salt stress on growth and nutrient acquisition in two durum wheat (Triticum durum Desf.) cultivars exhibiting differences in salt tolerance were investigated. The plants were grown in a sterilized, low P (silty clay) soil-sand mix. Three salt levels were created by adding NaCl solution to the soil through irrigation water, resulting in saturation extract (ECe) values of 1.2 (control), 4.1 (medium) and 6.7 dS m –1 (high salt stress), respectively. Mycorrhizal colonization occurred whether the soil was salt stressed or non-stressed and in both cultivars, but the extent of AMF colonization was higher in the control than under saline soil conditions. The salt-tolerant cultivar Petra had higher mycorrhizal colonization than the salt-sensitive cultivar Hourani-27. The shoot dry matter (DM) yield was higher in mycorrhizal than in non-mycorrhizal plants of both cultivars. Petra had higher shoot DM but not higher root DM than Hourani-27 plants. The enhancement in shoot DM due to AMF inoculation was 22 and 21% in the control, 31 and 58% at medium, and 18 and 60% at high salinity level for Petra and Hourani-27, respectively. For both cultivars, the contents of P, K, Zn, Cu and Fe were higher in mycorrhizal than in non-mycorrhizal plants under control and medium saline soil conditions. Shoot Na concentrations were lower in mycorrhizal than in non-mycorrhizal plants grown under saline conditions. The enhancement in P, K, Zn, Cu and Fe acquisition due to AMF inoculation was more pronounced in Hourani-27 than in Petra under saline soil conditions. The results suggest that Hourani-27 tends to benefit from AMF colonization more than Petra under saline soil conditions, despite the fact that Petra roots were highly colonized with the AM fungus. It appears that Hourani-27 is more dependent on AMF symbiosis than Petra.