ABSTRACT: Salinity adversely affects crop productivity and the quality of yield. The present work was carried out to estimate the changes in nitrogen metabolism under the influence of NaCl salinity in four selected grasses. All the species recorded a decrease in nitrate nitrogen content at the highest concentration of salinity stress (300 mM). Its maximum increase was 14 and 19% (100 mM) for Cymbopogon nardus and Cynodon dactylon, respectively. The maximum increase in nitrite nitrogen found was 11% (200 mM) in Cymbopogon nardus, 12% (100 mM) in Cynodon dactylon. The concentration of proline and amides in the leaves of all the experimental grasses showed a positive correlation with increasing concentrations of salinity. The maximum increase in proline content was 81, 88, 126, and 68% in Cymbopogon nardus, Cynodon dactylon, Pennisetum alopecuroides, and Vetiveria zizanioides, respectively, at 300 mM NaCl salinity. The concentration of free amino acids in the leaves of all the experimental grasses was considerably increased under saline condition and showed a positive correlation with increasing concentrations of salinity. Similar results were obtained in the case of amides. The concentration of nitrate reductase enzyme was elevated in Cymbopogon nardus and Pennisetum alopecuroides at lower salinity regime
