在我国北方大多数苹果栽培区,特别是高寒地区,由于天气严寒,绝对气温低,并且低温持续时间长,冻害发生频繁且普遍。轻则苹果树体局部死亡,树冠结构残缺不全,造成减产;重则果树整株大量死亡,损失更严重。因此,了解苹果树低温冻害机理,对保护树体安全越冬有重要的实践意义。一、冻害机理 Most apple-growing areas in northern China, especially in the alpine region, suffer from frequent and widespread frost damage due to the cold weather, low absolute temperature and long duration of low temperature. In the light of the partial death of the apple tree, the crown structure incomplete, resulting in reduced production; heavy tree mass heavy deaths, more serious losses. Therefore, to understand the mechanism of low temperature freezing injury of apple trees has important practical significance for the protection of winter tree security. First, the mechanism of frost damage