Exogenous nitric oxide (NO) ameliorates salinity-induced oxidative stress in tomato (Solanum lycopersicum) plants

Nitric oxide (NO) is involved in numerous physiological and stress responses in higher plants. Tomato is one of the most important vegetable crops in the world and previously it has been reported that salinity induced an oxidative stress affecting its redox and NO homeostasis. Using tomato plant exposed to 120 mM NaCl, it was studied whether the exogenous application of NO could ameliorate the negative effects provoked by salinity. Thus, nitric oxide provoked a significantly increase in the main antioxidative enzymes including superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR) and peroxidase (POD) activities, and also a raise of some enzymes involved in nitrogen metabolism including nitrate reductase (NR) and nitrite reductase (NiR) activities. Moreover, NO-treated plants showed a higher content in both proline and ascorbate but lower content of H2O2. These data indicate that the exogenous NO application is useful to mitigate the salinity-induced oxidative stress in tomato plants.