Investigating the efficacy of endophytic fungus Piriformosporaindica and Azospirillumstrains on alleviation of detrimental effect of salt stress on wheat (Triticumaestivum cv. Sardari)

Soil and water salinity are amongst the severe and progressive problems worldwide which affects most cropland areas of Iran. Using endophytic microorganisms (which are amongst the most important soil microorganisms) to alleviate the detrimental effect of environmental stresses such as salinity is recently globally considered. In order to test the effects of Azospirillum strains and fungus Piriformospora indica on wheat growth and physiological characteristics under salinity stress, a factorial experiment based on RCBD was conducted with three replications in the greenhouse of the College of Agriculture of Ilam University in 2011. Treatments included five bioinoculants (P. indica, salt adapted and non-adapted Azospirillum strains, dual inoculation of the both microorganisms and non-inoculated control) as well as four salinity levels (0.2, 4, 8 and 12 dSm-1). Results showed that P. indica had a significant positive effect on wheat growth, aboveground fresh and dry biomass, chlorophyll content and osmolite solutes of inoculated wheat plants under saline and non-saline conditions; so that fungus inoculation reduced the detrimental effects of salinity stress and caused an improved plant growth. Infested plants by Azospirillum strains resulted in higher biomass, higher osmolite solute as well as higher chlorophyll content. Biomass and chlorophyll content in plant infested by salt-adapted Azospirillum strains were higher than that of those inoculated with non-salt-adapted Azospirillum strains. Results obtained from the present study indicated that endophytic microorganisms might be used to increase the growth and yield of wheat plants under saline conditions.