Role of rhizospheric microorganisms in mitigating the adverse effect of salinity stress inPlantago ovatagrowth, biochemical and photosynthetic traits

This pot experiment was carried out to investigate the efficiency of plant rhizospheric microorganisms (PRMs) to counteract salinity stress inPlantago ovata. The treatments included soil salinity (2.5 (as control), 5 and 10 dS m(-1)), arbuscular mycorrhizal fungi (Control,Glomus mosseae, Rhizophagus intraradicesandFunneliformis mosseae) and phosphate solubilizing bacteria (Control andPseudomonas fluorescens). The highest amount of growth and yield parameters, relative water content (RWC), potassium (K+) and phosphorus (P) concentration, photosynthetic traits (chlorophyllaandb, carotenoid, maximal efficiency of PSII (fv/fm), variable fluorescence to initial fluorescence (fv/f(0)) and stomatal conductance (g(s))), antioxidant enzymes and the lowest sodium (Na+) concentration, malondialdehyde (MDA) and electrolyte leakage were observed in the plants treated with mixture ofRhizophagus intraradicesandPseudomonas fluorescensunder all salinity levels. Although all previously mentioned traits significantly and severely decreased under salinity stress, mucilage percentage, electrolyte leakage and Na(+)concentration were increased under salinity levels. In conclusion, the results suggested that inoculation of AMF (particularlyRhizophagus intraradices) in combination withPseudomonas fluorescensby the accumulation of proline along with decreased electrolyte leakage, maintenance of relative water content in leaves and selective uptake of K(+)ions could overcome detrimental effects of salinity stress in isabgol.