Laboratory of Plant Hardiness, Department of Horticultural Science and Landscape Architecture, University of Minnesota, St. Paul, Minnesota 55108.
Plant Physiol. 1983 Apr;71(4):749-55. doi: 10.1104/pp.71.4.749.
The heterogeneous ice nucleation characteristics and frost injury in supercooled leaves upon ice formation were studied in nonhardened and cold-hardened species and crosses of tuber-bearing Solanum. The ice nucleation activity of the leaves was low at temperatures just below 0 degrees C and further decreased as a result of cold acclimation. In the absence of supercooling, the nonhardened and cold-hardened leaves tolerated extracellular freezing between -3.5 degrees and -8.5 degrees C. However, if ice initiation in the supercooled leaves occurred at any temperature below -2.6 degrees C, the leaves were lethally injured.To prevent supercooling in these leaves, various nucleants were tested for their ice nucleating ability. One% aqueous suspensions of fluorophlogopite and acetoacetanilide were found to be effective in ice nucleation of the Solanum leaves above -1 degrees C. They had threshold temperatures of -0.7 degrees and -0.8 degrees C, respectively, for freezing in distilled H(2)O. Although freezing could be initiated in the Solanum leaves above -1 degrees C with both the nucleants, 1% aqueous fluorophlogopite suspension showed overall higher ice nucleation activity than acetoacetanilide and was nontoxic to the leaves. The cold-hardened leaves survived between -2.5 degrees and -6.5 degrees using 1% aqueous fluorophlogopite suspension as a nucleant. The killing temperatures in the cold-hardened leaves were similar to those determined using ice as a nucleant. However, in the nonhardened leaves, use of fluorophlogopite as a nucleant resulted in lethal injury at higher temperatures than those estimated using ice as a nucleant.
研究了非硬化和冷驯化的块茎茄属植物种和杂种的过冷却叶片在冰形成时的异质冰核形成特性和霜害。叶片的冰核活性在接近 0°C 的温度下较低，并且随着冷驯化进一步降低。在没有过冷却的情况下，非硬化和冷驯化的叶片可以在-3.5°C 至-8.5°C 之间容忍细胞外冻结。然而，如果过冷却叶片中的冰起始发生在任何低于-2.6°C 的温度下，叶片就会受到致命伤害。为了防止这些叶片过冷却，测试了各种成核剂的冰核形成能力。发现 1%水悬浮液的氟金云母和乙酰基苯胺在-1°C 以上的茄属叶片的冰核形成中是有效的。它们在蒸馏水中的冻结阈值温度分别为-0.7°C 和-0.8°C。尽管可以在高于-1°C 的温度下使用这两种成核剂在茄属叶片中引发冻结，但 1%水悬浮液的氟金云母显示出比乙酰基苯胺更高的整体冰核形成活性，并且对叶片无毒。使用 1%水悬浮液的氟金云母作为成核剂，冷驯化的叶片可以在-2.5°C 和-6.5°C 之间存活。冷驯化叶片的致死温度与使用冰作为成核剂确定的温度相似。然而，在非硬化叶片中，使用氟金云母作为成核剂会导致比使用冰作为成核剂更高的致死温度下的致命伤害。
