Abstract: In this study, rape (Brassica rapa L. ssp. chinensis, cv. Huaguan) was treated with 100 μmol/L sodium nitroprusside (SNP, a nitric oxide donor) solution treated, by vacuum infiltration for 2 min, and stored at 25 ℃ with RH 70% for 4 d. On 0, 1, 2, 3, 4 d, the postharvest quality indicators including yellowing rate and decay rate were determined; and the activity of reactive oxygen species (ROS) metabolism related enzymes, including superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR). The results showed that the yellowing rate and decay rate of SNP treated group are significantly lowered better than that of control. SNP treatment makes the SOD and APX activities of rape increase during the whole storage time, but the GR activity decreases from 1 d to 3 d. Moreover, SNP treatment makes the CAT activity increase on the first day, but decrease after the second day. It showed that 100 μmol/L NO donor, SNP, significantly improves postharvest rape quality, and this effect is mightily promoting CAT activity in the beginning of the storage and promoting SOD and APX activities during storage time.

Key words: pakchoi, nitric oxide, postharvest quality, ROS metabolism related enzymes