Ansart A, Vernon P, Daguzan J
Université de Rennes 1, UMR 6553 Ecobio, Equipe Ecophysiologie, Bâtiment14, 263 Avenue du Général Leclerc, CS 74205, 35042 Rennes Cedex, France.
J Comp Physiol B. 2002 Oct;172(7):619-25. doi: 10.1007/s00360-002-0290-z. Epub 2002 Aug 21.
The land snail Helix aspersa can be considered partially tolerant to freezing, in the sense it can survive some ice formation within its body for a limited time, and possesses a limited ability to supercool. This study aimed at understanding what factors are responsible for the variation of the temperature of crystallization ( Tc) in a littoral temperate population. The ability to supercool was maximal (ca. -5 degrees C) during dormancy periods (hibernation and aestivation) and minimal (ca. -3 degrees C) during spring and autumn, in relation with the decrease of water mass and the increase of osmolality. Tc decreased in October to remain stable through late autumn and winter; it increased quickly with the awakening of animals in April. Snails with an epiphragm had a significantly higher ability to supercool (ca. -4.8 degrees C) than snails which did not form an epiphragm (ca. -4.2 degrees C). The animals' size had a weak but significant influence on the realization of the Tc. It appeared that there was not a real cold-hardiness strategy in this population; rather a sum of parameters, varying in consequences of the external conditions and of the activity cycle, which are responsible for the enhancement of the supercooling ability during winter.
陆地蜗牛玛瑙螺在一定程度上可被视为耐冻的，因为它能在体内形成一些冰的情况下存活有限的时间，并且具有有限的过冷却能力。本研究旨在了解哪些因素导致沿海温带种群中结晶温度（Tc）的变化。过冷却能力在休眠期（冬眠和夏眠）达到最大值（约-5摄氏度），而在春季和秋季达到最小值（约-3摄氏度），这与水量减少和渗透压增加有关。Tc在10月下降，在深秋和冬季保持稳定；随着4月动物苏醒，它迅速上升。有隔膜的蜗牛比没有形成隔膜的蜗牛具有显著更高的过冷却能力（约-4.8摄氏度）比没有形成隔膜的蜗牛（约-4.2摄氏度）。动物的大小对Tc的实现有微弱但显著的影响。看来这个种群中没有真正的抗寒策略；相反，是一系列参数，因外部条件和活动周期的不同而变化，这些参数导致了冬季过冷却能力的增强。
