杏品种花器官过冷却点及结冰点的研究

 【目的】弄清不同发育时期杏花、幼果过冷却点和结冰点变化，不同花器官过冷却点和结冰点的差异，为杏花期霜冻害机理的研究提供基础数据。【方法】以3个杏品种为试材，利用能准确模拟自然界霜夜降温过程的人工霜箱，测定不同发育时期花器官、幼果的过冷却点、结冰点，统计杏花器官受冻情况。【结果】随杏花发育进程的推移，3个杏品种自大蕾期至幼果期过冷却点、结冰点呈现明显上升趋势，表明抗寒力下降；不同品种、不同花器官过冷却点、结冰点存在差异，品种间表现为花器官过冷却点、结冰点越低，抗性越强，从过冷却点到结冰点的平均温度“跃升”值越大；过冷却点并不表示一个确定值，而是一个范围。花瓣过冷却点频率分布较雄蕊、雌蕊分散；杏花器官通过保持过冷却状态回避低温伤害，但对结冰十分敏感，一旦结冰，升温后花器官均受害而褐变。【结论】不同发育时期、不同品种不同花器官过冷却点和结冰点存在差异。

Study on Supercooling Point and Freezing Point in Floral Organs of Apricot

【Objective】Making clearing the anti-frost capability for different developmental stages, different cultivar and different floral organs plays an important role in forecasting and preventing from late frost damage in apricot.【Method】With an artificial climate chamber simulating frost, the supercooling point and freezing point were determined in three apricot cultivars, and the degree of freezing damage were calculated.【Result and Conclusion】The anti-frost capability was relation to developmental stages, the result showed that young fruit stage was sensitive to forst, blooming stage take second place. Supercooling poin and freezing point varied with different cultivars and floral organs, which showed that the higher the anti-frost capability of apricot cultivar was, the lower supercooling point and freezing point were, and the higher the value between supercooling point and freezing point was. With respect to floral organs, supercooling point and freezing point of stamen and pistil were higher than petal, which may be in relationship with development and water content. Supercooling point frequency of petal was more dispersing than those of stamen and pistil, and supercooling point of petal was 1～2℃ lower than those of stamen and pistil. By keeping supercooling state, apricot flower could obviate freezing damage, but it was sensitive to freezing, and floral organs turned brown after freezing.