越冬季杜鹃花芽的过冷却：附加的冷冻参数。
Supercooling in overwintering azalea flower buds: additional freezing parameters.
机构信息
Laboratory of Plant Hardiness, Department of Horticultural Science, University of Minnesota, St. Paul, Minnesota 55108.
出版信息
Plant Physiol. 1977 Feb;59(2):326-8. doi: 10.1104/pp.59.2.326.
Results of calorimetric, nuclear magnetic resonance, and low temperature light microscopic studies on supercooled azalea (Rhododendron kosterianum, Schneid.) floral primordia are reported. Heat release during freezing of the supercooled floral primordia is in the range predicted for supercooled pure water. Spin-lattice and spin-spin relaxation times measured by pulsed nuclear magnetic resonance spectroscopy decreased after freezing, suggesting that a redistribution of tissue water is associated with injury to the floral primordium. The calorimetric and low temperature microscopy studies showed no detectable ice formation in floral primordia until the major freezing event at low temperature. No resistance to ice growth is found to exist in the primordium tissues, indicating that a freezing barrier or thermodynamic equilibrium exists between the unfrozen primordium and other flower bud parts which contain ice at subfreezing temperatures.
报告了对过冷的兴安杜鹃（Rhododendron kosterianum Schneid.）花原基进行量热法、核磁共振和低温光学显微镜研究的结果。过冷花原基冷冻过程中的热量释放范围与过冷纯水的预测值一致。通过脉冲核磁共振光谱测量的自旋晶格和自旋-自旋弛豫时间在冷冻后降低，表明组织水的重新分布与花原基的损伤有关。量热法和低温显微镜研究表明，在低温下发生主要冷冻事件之前，花原基中没有检测到冰的形成。在原基组织中没有发现对冰生长的抵抗力，这表明在未冻结的原基和其他在亚冷冻温度下含有冰的花蕾部分之间存在冷冻屏障或热力学平衡。
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