Energy and proline metabolisms participate in the occurrence of chilling injury in cold-stored Chinese olive fruit

Cold storage is widely applied in postharvest fruit for quality maintenance. However, Chinese olive fruit suffers severe chilling injury (CI) during improper cold storage. In present work, the metabolisms of energy and proline in Chinese olive fruit during CI occurrence were investigated. Compared with the cold storage at 8 °C, the cold storage at 2 °C raised CI index, reduced the activities of Mg2+-ATPase, Ca2+-ATPase and H+-ATPase in the membranes of mitochondria, plasma and vacuole, decreased the levels of energy charge, ATP, and ADP, but elevated the content of AMP in Chinese olive fruit. Furthermore, 2 °C cold-stored fruit presented lower proline amount, lower P5CS and OAT activities, but higher PDH activity. These data demonstrated that the reduced levels of energy and proline were associated with the CI occurrence of cold-stored Chinese olives.