Growth and nitrogen-fixing performances of medicago truncatula-Sinorhizobium meliloti symbioses under salt (NaCl) stress: Micro- and macro-symbiont contribution into symbiosis tolerance

  • Haythem Mhadhbi
  • Mohamed Elarbi Aouani


The effect of salt (NaCl) stress on plant growth and nitrogen-fixing apparatus was studied for symbiotic associations established between three Medicago truncatula lines inoculated and two Sinorhizobium meliloti strains. Salinity modulated all parameters analyzed as indices of growth performance, nitrogen-fixing capacity (acetylene-reduction assay) and nodule antioxidant system. Under stressful conditions, symbioses showed variability of response to salt application. Contrasting symbiotic associations were identified for nodulation, nitrogen-fixing capacity and salt tolerance. The total variance of analyzed performance indices under stressful conditions depended essentially on plant genotype factor. In nodules, the NaCl application had a decreasing effect on the rates of protein content and some antioxidant enzymes mainly catalase. Other enzymes such as guaiacol peroxidase increased in stressed nodules.


Salt Stress Rhizobial Strain Guaiacol Peroxidase Symbiotic Nitrogen Fixation Symbiotic Partner 
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Copyright information

© Birkhäuser Verlag/Switzerland 2008

Authors and Affiliations

  • Haythem Mhadhbi
    • 1
  • Mohamed Elarbi Aouani
    • 1
  1. 1.Laboratoire Interactions Légumineuses Microorganismes (LILM)Centre de Biotechnologie de Borj Cedria (CBBC)Hammam lifTunisie

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