Chilling-induced oxidative stress and antioxidant responses in mume (Prunus mume) fruit during low temperature storage

Mume (Prunus mume Sieb. et Zucc.) fruit are harvested and consumed at the mature green stage and have a short storage life at ambient temperature. While cold temperature extends their storage life, improper refrigeration causes severe chilling injury (CI), with fruit suffering more severe CI at of 5-6 degrees C than at 1 degrees C. The objective of this research was to determine the involvement of reactive oxygen species (ROS) and antioxidant systems in fruit under chilling stress. 'Nankou' fruit were stored at 1 degrees C or 6 degrees C for 15 days. Hydrogen peroxide, a preventive ROS, decreased at a slower rate at 6 degrees C than 1 degrees C during storage. Malondialdehyde (MDA), an indicator of lipid peroxidation caused by ROS, increased during storage and the contents were higher in fruit stored at 6 degrees C than at 1 degrees C. On the other hand, fruit stored at 6 degrees C had a lower total antioxidant capacity (TAC) and lower activities of antioxidant-related enzymes including superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) than at 1 degrees C. These results indicate that the fruit at 6'C had more oxidative stress; thus the fruit had more severe CI symptoms than at 1 degrees C. (c) 2007 Elsevier B.V. All rights reserved.