Effects of NO₃^- on antioxidant enzyme activity and reactive oxygen content in roots of sweet cherry under water-logging condition

The objective of this study is to elucidate the effects of NO3- on antioxidant enzyme activity and reactive oxygen content in roots under water-logging condition. We conducted a pot study using Meizao/Colt sweet cherry (Prunus pseudocerasus Lindl.). They were transferred into the solution with 0, 10, 20, 30 mmol/L KNO3 and 10 mmol/L K2SO4 for 6 days to determine antioxidant enzyme activity and reactive oxygen content in sweet cherry roots. The results showed that under water-logging condition, the activity of superoxide dismutase (SOD), peroxidase (POD), catlase (CAT) and the contents of superoxide (O2—), hydrogen peroxide (H2O2), and malondialdehvde (MDA) in roots of sweet cherry increased significantly in the early period of treatment and then decreased in the later period. The developmental stages of NO3- treatments was the same as CK. NO3- enhanced the activities of antioxidant enzymes including SOD, POD and CAT, which were higher than CK, while the concentrations of O2—, H2O2 and MDA were lower than CK and decreased under water-logging condition. We conclude that the addition of NO3- can alleviate the causedby water-logging conditionon sweet cherry by increasing antioxidant enzyme activities, and decreasing reactive oxygen content.