宁夏苹果花期霜冻敏感性指标研究

Research on frost sensitive indexes in apple blossom in Ningxia

苹果花期霜冻指标是果园霜冻预报预警、防御的基础,本文运用人工模拟霜箱,以富士、嘎啦和乔纳金苹果为试验对象,设置过冷却模拟试验设5个温度梯度和4个持续时间共计20个试验处理,模拟研究了苹果花期霜冻敏感性指标。结果表明:苹果花苞期花瓣、盛花期花瓣和子房以及幼果期的幼果平均过冷却点在-3.51℃^-3.27℃,结冰点变化范围在-2.94℃^-2.65℃。苹果花期低温敏感范围在-2.5℃^-3.5℃之间,不同花器官、不同品种、不同低温持续时间和不同发育阶段之间有所差异,其中,在苹果花的花瓣、子房、雄蕊和雌蕊等不同花器官中,花瓣最不耐冻,子房和雌、雄蕊随温度降低变异较大;不同类型花耐受冻顺序为花苞>半开花>全开花;-2.5℃^-3.0℃温度处理下,致死率随持续时间增加明显,温度高于或低于这个范围,持续时间对致死率影响不大;3个苹果品种中,富士最不耐冻,其次是乔纳金和嘎啦。

Frost index in apple blossom is the foundation for frost forecast,warning and defense in orchard.This paper taking the Fuji,Jonagold and Gala as the test objects,utilizing the artificial frost simulating boxes to set up the cooling simulation test and 20 experimental treatments with 5 temperature gradients and 4 duration times,have been simulated and researched the frost sensitive indexes in apple blossom. The results showed that： The average supercooling point was from-3.51℃ to-3.27℃ for the petal in bud period and blossom,ovary and young fruit stage. The change range of freezing point was-2.94℃ to-2.65℃. The low sensitive temperature in apple blossom was-2.5℃ to-3.5℃. There were some difference between different floral organs,varieties,low temperature duration and developmental stage. Among them,for all floral organs,the petal was the most intolerant to frost than other floral organ as ovary,stamens and pistils. The variation was rather big with temperature decrease for the ovary,stamen and pistil. The order of resistance to cold for different flower type was budsemi flowering full flowering. The death rate was obviousness with increasing the duration,under the temperature treatment of- 2. 5℃ ∽- 3. 0℃.While the duration had little effect on death rate when the temperature was higher or less this range of-2.5℃ to-3.0℃. In three test varieties,the Fuji was the most intolerant to cold,the second was Jonagold and Gala.