Tomato growth in response to salinity and mycorrhizal fungi from saline or nonsaline soils

Tomato (Lycopersicon esculentum Mill. 'Heinz 1350 VF 402') seedlings were inoculated with populations of vesicular-arbuscular mycorrhizal (VAM) fungi collected from saline or nonsaline soil or remained nonmycorrhizal as a control. Plants then were salinated for 8 weeks at 1.0, 2.0, 5.0, or 10.0 dS · m^-1 produced by dilutions of 1 M NaCl: 1 M CaCl₂ in deionized water. Inoculation with VAM fungi from nonsaline soil enhanced shoot growth, while VAM fungi from saline soil suppressed shoot and root growth. Plants inoculated with VAM fungi from nonsaline soil and non-VAM control plants showed a quadratic increase in leaf Cl^- concentration in response to an increased salinity level, whereas plants inoculated with VAM fungi from saline soil showed a linear increase in leaf Cl^- concentration. Mycorrhizal-induced growth responses and changes in leaf Cl^- concentration were not associated with any apparent alterations in tomato plant P status. Although VAM fungi originating from saline soil did not promote plant growth, reduction in leaf Cl^- concentration mediated by these VAM fungi at moderate salinity levels may have beneficial implications for plant survival in saline soil.