Effective microorganisms improve growth performance, alter nutrients acquisition and induce compatible solutes accumulation in common bean (Phaseolus vulgaris L.) plants subjected to salinity stress Abstract No information is available concerning effective microorganisms (EM) influence on the ionic and osmotic responses in plants grown in salty soils. Therefore, as a first approach, this study focuses on the contribution of EM to nutrient acquisition and compatible solutes accumulation in salt-stressed plants. It assesses some mechanisms underlying alleviation of salt toxicity by EM application, and also directs to establish a possible interrelationship between EM application as well as ionic and osmotic stresses tolerance in plants exposed to saline soils. Phaseolus vulgaris cv. Nebraska plants were grown under non-saline or saline conditions (2.5 and 5.0 dS m -1 ) with and without EM application. Salinity stress significantly decreased growth, productivity, membrane stability index, relative water content, concentrations of N, P, K ? , Fe, Zn and Cu, and the ratios of K ? /Na ? , Ca 2? /Na ? and Mg 2? / Na ? . However, EM application protected plants against the detrimental effect of salinity and significantly improved the above parameters. Concentrations of Ca ?2 , Mg ?2 , soluble sugars, free amino acids, proline and glycinebetaine were increased under saline conditions; moreover they further increased in salt-stressed plants treated with EM. Lipid peroxidation, hydrogen peroxide content, electrolyte leakage and Na ? level were increased in response to salinity and significantly decreased when stressed plants treated by EM. Reduction in Na uptake together with a concomitant increase in N, P, K, Ca, Mg, Fe, Zn and Cu absorption and a high compatible solutes accumulation may be an efficient mechanism used by EM-treated plants to gain tolerance against salinity stress.
