Influence of exogenously applied nitric oxide on strawberry (Fragaria x ananassa) plants grown under iron deficiency and/or saline stress

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 (Fragariaxananassa cv. Camarosa) grown under iron deficiency (ID), salinity stress or combination of both. The experimental design contained control, 0.1mM FeSO4 (ID, Fe deficiency); 50mM NaCl (S, Salinity) and ID+S. Plants were sprayed with 0.1mM SNP or 0.1mM 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 (H2O2) in plant leaves compared to those in plants grown with either of the single stresses. NO treatment effectively reduced EL, MDA and H2O2 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.