A study was carried out to assess the protective effects of exogenously applied
nitric oxide (NO) in the form of its donor
sodium nitroprusside (SNP) to strawberry seedlings (Fragaria × ananassa cv. Camarosa) grown under
iron deficiency (ID), salinity stress or combination of both. The experimental design contained control, 0.1 mM FeSO4 (ID, Fe deficiency); 50 mM NaCl (S, Salinity) and ID + S. Plants were sprayed with 0.1 mM SNP or 0.1 mM
sodium ferrocyanide, an analogue of SNP containing no NO. The deleterious effects of ID + S treatments on plant fresh and dry matters, total
chlorophyll and
chlorophyll fluorescence were more striking than those caused by the ID or S treatment alone. Furthermore, combination of salinity and
iron stress exacerbated
electrolyte leakage (EL) and the levels of
malondialdehyde (MDA) and
hydrogen peroxide (H2 O2 ) in plant leaves compared to those in plants grown with either of the single stresses. NO treatment effectively reduced EL, MDA and H2 O2 in plants grown under stress conditions applied singly or in combination. Salt stress alone and with ID reduced the
superoxide dismutase (EC1.15.1.1) and
catalase (EC 1.11.1.6) activities but increased that of POD (EC 1.17.1.7). Exogenously applied NO led to significant changes in
antioxidant enzyme activities in either ID or S than those by ID+S. Overall, exogenously applied NO was more effective in mitigating the stress-induced adverse effects on the strawberry plants exposed to a single stress than those due to the combination of both stresses.