梨树花芽休眠解除与活性氧代谢的关系

Relationship Between Breaking of Dormancy and Reactive Oxygen Species Metabolism in Flower Buds of Pear

梨树(Pyrus bretschneideri Rehd.)自然休眠和休眠解除时,花芽的活性氧代谢发生变化。O2产生速率和H2O2的含量在休眠期间上升,在休眠后期下降。抗氧化系统中SOD活性在自然休眠期呈下降趋势,自然休眠结束活性上升。POD和CAT活性在自然休眠期上升。抗氧化物质ASA和GSH的含量随休眠进行而下降,休眠解除过程中重新升高。APX和GR的活性在休眠期间活性下降,休眠结束活性迅速上升。这些结果表明:花芽的休眠与活性氧的代谢有很大关系。

The metabolism of reactive oxygen species in pear (Pyrus bretschneideri Rehd.) flower buds changes greatly during their natural dormancy in winter. The O2- production rate increases rapidly during the period of dormancy, but decreases when dormancy finishes (Fig.5). H2O2 content goes up significantly at the early stage of dormancy, but afterwards falls gradually (Fig.5). However, ascorbic acid (AsA) and reduced glutathione (GSH) contents show a different changing trend: descending at first and keeping at relatively low levels during the process of dormancy, but rising during breaking of dormancy (Fig.4). The activities of superoxide dismutase (SOD), ascorbic peroxidase (APX) and gluthione reductase (GR) descend during the process of dormancy, but rise during breaking of dormancy, although at different rates for different enzymes (Figs. 1,3). On the contrary, theactivity of catalase (CAT) incresses sharply at the beginning of dormancy, keeps at a stable high level during dormancy, and gradually decreases at the end of dormancy period (Fig.2). The activity of peroxidase (POD) even keeps increasing during dormancy and breaking of dormancy (Fig.1). The results show that the metabolism of reactive oxygen species has certain strong correlation with the natural dormancy of pear flower buds in winter.