Gwinner E
Naturwissenschaften. 1981 Nov;68(11):542-51. doi: 10.1007/BF00401662.
During the last years, evidence has been accumulated indicating that the annual cycles of physiological and behavioral functions in animals are often preprogrammed as endogenous circannual rhythms. Under seasonally constant environmental conditions these rhythms persist for several cycles with periods deviating from year, whereas under natural conditions they are usually synchronized by seasonal changes in the environment, particularly that of photoperiod. Hence, the annual rhythm of photoperiod constitutes a Zeitgeber for the endogenous rhythmicity rather than providing causal stimuli that release particular activities at particular times of the year. On the basis of this new concept several peculiarities of annual biological rhythms under the influence of photoperiodic cycles with different properties can be better understood, at least at a formal level.
在过去几年中，已有证据表明，动物生理和行为功能的年度周期通常作为内源性年节律预先设定。在季节性恒定的环境条件下，这些节律会持续几个周期，其周期与一年有所偏差，而在自然条件下，它们通常会通过环境的季节性变化，特别是光周期的变化来同步。因此，光周期的年度节律构成了内源性节律性的一个授时因子，而不是提供在一年中特定时间释放特定活动的因果刺激。基于这一新概念，至少在形式层面上，可以更好地理解在具有不同特性的光周期循环影响下年度生物节律的几个特点。
