Reduced chilling injury in cucumber by nitric oxide and the antioxidant response

Cucumber fruit were pre-treated with 25 mu l l(-1) oxide (NO) for 12 h at 20 degrees C, and then stored at 2 +/- 1 degrees C and 95% relative humidity for 15 days. Chilling injury index, membrane permeability, lipid peroxidation, superoxide anion (O-2(center dot)-) production rate, H2O2 content, activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), peroxidase (POD), and DPPH-radical scavenging activity were measured. The results showed that the application of NO at 25 mu l l(-1) was most effective in reducing Cl in cucumber fruit. The treatment reduced the increases in membrane permeability and lipid peroxidation, delayed the increases in both O-2(center dot)- production rate and H2O2 content. The NO-treated fruit exhibited significantly higher activities of SOD, CAT, APX and POD and higher DPPH-radical scavenging activity than control fruit during the storage. The overall results suggest that NO enhanced chilling tolerance in cucumber fruit by improving the antioxidative defence system. (C) 2011 Elsevier Ltd. All rights reserved.