In conclusion, it may be said that N availability differentially regulates ethylene and proline production and responses of plants to salt stress. Plants showed maximum photosynthesis and growth with sufficient-N (10 mM N), but inhibition was observed with excess-N (20 mM N) under no salt stress. In contrast, excess-N proved beneficial for plants under salt stress. The negative effects of excess-N in plants without salt stress were due to increased ethylene production and oxidative stress. But, excess-N treatment in thepresence of salt stress optimized ethylene production, which regulates proline biosynthesis and photosynthesis and growth of plants.