Abstract: To study the regulation by exogenous nitric oxide (NO) and N-acetyl-L-cysteine(NAC)on mitochondrial antioxidative system of Feicheng peaches during cold storage. Feicheng peaches were dipped in 15 μmol/L NO,80 mmol/L N-acetyl-L-cysteine (NAC,reactive oxygen species scavenger) plus 15 μmol/L NO,and 5 μmol/L c-PTIO (NO scavenger) solution,respectively. The changes in mitochondrial respiration,mitochondrial membrane potential,the contents of malonaldehyde (MDA) and reactive oxygen species (ROS) and the activities of antioxidant enzymes were detected. Treatment with 15 μmol/L NO significantly decreased mitochondrial ROS content. Especially at the 1st week,mitochondrial ROS content in peaches treated with 15 μmol/L NO was only 50% of the control. Mitochondrial ROS content in peaches treated with 80 mmol/L NAC-15 μmol/L NO was significantly lower than that of the control and other treatments after 2 weeks,while treatment with 5 μmol/L c-PTIO increased the content of mitochondrial ROS. The activities of antioxidative enzymes (POD,SOD and CAT) in mitochondria of peaches treated with 15 μmol/L NO was higher than that of the control and treatment with 5 μmol/L c-PTIO. Treatment with 80 mmol/L NAC-15 μmol/L NO increased the activity of mitochondrial SOD and decreased the activities of mitochondrial POD and CAT. Treatment with 5 μmol/L c-PTIO decreased the activities of antioxidative enzymes in mitochondria. Mitochondrial MDA content in peaches treated with 15 μmol/L NO was lower than that of the control and other treatments during the storage except for the second week. However,mitochondrial MDA content in peaches treated with 80 mmol/L NAC-15 μmol/L NO was significantly higher than that of the control and other treatments after 1 week. Mitochondrial MDA content in peaches treated with 5 μmol/L c-PTIO was higher than that of the control and treatment with 15 μmol/L NO in the second and third week. Mitochondrial membrane potential was improved by treatment with 15 μmol/L NO,reached the maximum,which was 1.2 times as high as that of the control,at 3 weeks. Mitochondrial membrane potential of peaches treated with 80 mmol/L NAC-15 μmol/L NO was higher than that of the control and other treatments. However,treatment with 5 μmol/L c-PTIO decreased mitochondrial membrane potential. The mitochondrial respiration of peaches was inhibited by treatment with 15 μmol/L NO. Mitochondrial respiration peak of peaches treated with 80 mmol/L NAC-15 μmol/L NO appeared 1 week earlier than the control. Treatment with 5 μmol/L c-PTIO maintained high respiration of mitochondria. Exogenous nitric oxide and N-acetyl-L-cysteine could improve the antioxidant capacity of mitochondrial antioxidant system of peaches during storage,and delay the decrease of mitochondrial function.

Key words: Peach (Prunus persica), Nitric oxide, N-acetyl-L-cysteine, Mitochondria, Antioxidant system

CLC Number: 

• S662.1