Influence of host genotypes on growth, symbiotic performance and nitrogen assimilation in faba bean (Vicia faba L.) under salt stress

Abstract

Fifteen genotypes of faba bean (Vicia faba L.) were inoculated with salt-tolerant Rhizobium leguminosarum biovar. viciae strain GRA 19 in solution culture with 0 (control) and 75 mM NaCl added immediately after transplanting. Genotypes varied in their tolerance of high levels of NaCl. Physiological parameters (dry weight of shoot and root, number and dry weight of nodules) were not affected by salinity in lines VF46, VF64 and VF112. Faba bean line VF60 was sensitive to salt stress. Host tolearance appeared to be a major requisite for nodulation and N2 fixation under salt stress. Tolerant line VF112 sustained nitrogen fixation under saline conditions. Activity of the ammonium assimilation enzymes glutamine synthetase and glutamate synthase, and soluble protein content, were reduced by salinity in all genotypes tested. Evidence presented here suggests a need to select faba bean genotypes that are tolerant to salt stress.