霜冻过程温光因子分析及模拟霜冻条件的建立

Analysis of Temperature and Light Factors during Frost Events and Establishing Conditions for Simulated Frost

近年来霜冻对我国果树产业的影响越来越大,建立科学的模拟霜冻程序对于加强果树霜冻基础研究十分必要。基于对大田霜冻天气的实际观测,分析了自然霜冻在降温速度、低温极限、升温速度以及霜后光照条件方面的特点,建立了用于实验室环境下的霜冻处理程序。结果表明,霜冻发生时气温的变化主要包括降温、低温维持和升温3个阶段。降温和升温阶段气温的变化近似线性;霜后一般伴随较强的光照。经研究确定模拟霜冻条件为:黑暗环境下,气温在30分钟内从室温(20°C)降到5°C,在5°C维持30分钟,之后以0.8°C·h^(–1)的速度降到–2°C,在–2°C维持2小时,再以4.7°C·h^(–1)的速度回升到5°C结束霜冻处理。霜冻处理后的恢复条件为气温16°C及光强800μmol·m^(–2)·s^(–1)。

Frost has had a prominent influence on the fruit industry in China in recent years. We need to establish a system to simulate frost treatment for fruit trees. Based on observations of frost events in field, we analyzed the characteristics of frost in terms of cooling rate, the low temperature limit, warming rate, and light conditions after frost treatment and established a system to simulate frost treatment in the laboratory. Temperature during the frost treatment in field could be divided into three stages: cooling, extreme temperature maintenance and warming. The temperature during cooling and warming stages changed in an approximately linear manner. Frost is generally followed by high intensity light. The simulated frost process was determined as followed: the temperature drops from room temperature(20°C) to 5°C in 30 min, and is maintained at 5°C for 30 min, then decreases to –2°C at a rate of 0.8°C·h–1, is maintained at –2°C for 2 h, then increases to 5°C at a rate of 4.7°C·h(–1 in the dark. The recovery condition after frost was 16°C and 800 μmol·m–2·s–1.