Effect of salinity and drought on symbiotical and biochemical properties of Onobrychis and alfalfa

To search for an alternative to alfalfa under conditions of salinity and drought, a comparative study was carried out to explore the effect of salinity on the symbiosis of alfalfa and local esparcet species (Onobrychis transcaucasica and Onobrychis chorassanica) inoculated with their nodule bacteria. The salinity of up to 30 mM NaCl insignificantly affected the biomass growth of shoots and roots of alfalfa plants, but the increase in the salinity from 30 to as high as 140 mM NaCl led to the biomass decrease. The gradual growth suppression of both Onobrychis plants species started from 200 mM NaCl, and salinity concentration 300 mM NaCl was critical (sub-lethal) for plants independently of inoculation by nodule bacteria. In shoot and roots of alfalfa, both Onobrychis plant species subject to salt stress, aldehyde oxidase and xanthine dehydrogenase enzymes and different number of their isoforms as well as their electrophoretic mobilities/activities were found.