Storey K B, Storey J M
Comp Biochem Physiol A Comp Physiol. 1986;83(4):613-7. doi: 10.1016/0300-9629(86)90699-7.
The ability to tolerate extracellular freezing as an adaptation for winter survival was tested in seven species of terrestrially-hibernating amphibians found in eastern Canada. All species had only moderate supercooling abilities, with whole animal supercooling points of -1.5 to -3 degrees C. Two salamander species, Plethodon cinereus and Ambystoma laterale, and the toad, Bufo americanus, were freezing intolerant and were killed when frozen for 24 hr at temperatures just below their supercooling points. The major winter strategy of these animals appears to behavioural avoidance of subzero temperatures. Four species of frogs Rana sylvatica, Hyla versicolor, Hyla crucifer and Pseudacris triseriata, survived extracellular freezing at moderate subzero temperatures (-2 to -4 degrees C) for periods of time ranging up to 2 weeks. All four frog species accumulated low molecular weight carbohydrates as cryoprotectants, glycerol being the major cryoprotectant in adult H. versicolor, while immature adults of this species as well as the other three species all produced high levels of glucose as the cryoprotectant.
在加拿大东部发现的七种陆地冬眠两栖动物中，测试了它们耐受细胞外结冰作为冬季生存适应方式的能力。所有物种的过冷却能力都只是中等程度，整个动物的过冷却点在-1.5至-3摄氏度之间。两种蝾螈物种，即灰口螈和侧纹钝口螈，以及美洲蟾蜍，不耐受结冰，当在略低于其过冷却点的温度下冷冻24小时时就会死亡。这些动物主要的冬季策略似乎是行为上避免零度以下的温度。四种蛙类，即林蛙、变色雨蛙、十字雨蛙和三齿拟蝗蛙，在中等零度以下温度（-2至-4摄氏度）下能在细胞外结冰状态下存活长达2周的时间。所有这四种蛙类都积累低分子量碳水化合物作为抗冻剂，甘油是成年变色雨蛙中的主要抗冻剂，而该物种的未成熟个体以及其他三种物种都产生高水平的葡萄糖作为抗冻剂。
