Sodium nitroprusside and salicylic acid decrease antioxidant enzymes activity in soybean

The present study investigated the effect of salicylic acid (SA) and sodium nitroprusside (SNP) on germination and activity of antioxidant enzymes in soybean under oxidative stress using a factorial experiment based on completely randomized design with three replications. Treatments included SA (0 and 1 mM), SNP (0, 30, and 60 µM), and H2O2 (0, 50, and 100 µM). Results showed that the highest germination percentage (97%) was related to 1 mM SA without SNP and H2O2 which was 6% greater than the control and the highest germination rate (0.72) was related to 1 mM SA and 60 µM SNP without H2O2 (6.63% greater than the control). The highest activity for superoxide dismutase (89.17 units mg -1 protein) was achieved by application of 100 µM H2O2 without SNP. In conclusion, oxidative stress increased all antioxidant enzymes while SNP application decreased the enzyme activity and stress severity.