Legumes' sensitivity to salt is exacerbated under growth conditions requiring nitrogen fixation by the plant. Phosphorus (P) deficiency is widespread in legumes, especially common bean (Phaseolus vulgaris L). To examine the performance of P. vulgaris under salt stress conditions, a field experiment was conducted using two recombinants inbred lines (RILs) 115 (P‐deficiency tolerant) and 147 (P‐deficiency susceptible), grown under different salinity levels (L) (1.56, 4.78, and 8.83 dS m−1 as LI, L2, and L3, respectively) and supplied with four P rates (0, 30, 60, and 90 kg ha−1 P as P0, P30, P60, and P90, respectively) in order to assess the impact of P on salt tolerance. Results indicate that growing both RILs at P60 or P90 under all salinity levels (especially L1) significantly increased total chlorophyll, carotenoids, total soluble sugars, total free amino acids, and proline. Increasing P supply up to P60 under all salinity levels significantly induced higher accumulation of P, K+, Ca2+ and Mg2+ leaves in both RILs. Based on quadratic response over all locations, the maximum seed yield of 1.465 t ha−1 could be obtained at application of P 81.0 kg ha‐1 in RIL115, while seed yield of 1.275 t ha−1 could be obtained with P rate of 78.3 kg ha−1 in RIL147. RIL115 exhibited more salt‐tolerance with positive consequence on plant biomass and grain yield stability. Improved salt tolerance through adequate P fertilization is likely a promising strategy to improve P. vulgaris salinity tolerance and thus productivity, a response that seems to be P‐rate dependent.

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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.

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