Influence of Rhizobium leguminosarum b.v. phaseoli bacteria on growth, activity of antioxidant enzymes and nutrient uptake of common bean (Phaseolus vulgaris) under salinity stress

This research investigate the potential of Rhizobium leguminosarum b.v. phaseoli to improve growth and nutritional status of common bean (Akhtar cultivar) at three levels of salinity of S0, S1 and S2 (0, 35 and 70 mM sodium chloride, or 0, 3 and 6 ds/m, respectively). The greenhouse experiment was conducted as a factorial design in randomized completely with three replications by using the sterile sand-perlite (2:1 v/v) as a culture substrate. The results showed that salinity decreased plant growth, regardless of microbial treatment and stress level. The inoculated plants with rhizobium had greater shoot and root biomass than the non-inoculated plants at all salinity levels. Salinity stress decreased enzyme activity catalase and potassium and nitrogen concentrations of shoot and increased enzyme activity peroxidase sodium concentration of shoot, particularly in non-inoculated plants with rhizobium. At salinity levels of S1 and S2, enzyme activity catalase of inoculated plants with rhizobium about 196% and 259% and enzyme activity peroxidase about 93%, 73% and 7% was increased than the non-inoculated plants, respectively. Inoculation of rhizobium at salinity levels of S1 and S2, resulted in increasing of potassium concentration about 84% and 10% and decreasing of sodium concentration about 50% and 70%, respectively. Also, the inoculated plants with rhizobium had higher nitrogen concentrations at S0 and S2 in compare to the non-inoculated. Shoot phosphorous concentration of inoculated plants with rhizobium was higher about 55% than the non-inoculated plants.