Panda Satchidananda, Hogenesch John B, Kay Steve A
Department of Cell Biology, The Scripps Research Foundation, 10550, North Torrey Pines Road, La Jolla, CA 92037, USA.
Novartis Found Symp. 2003;253:73-82; discussion 82-8, 102-9, 281-4.
The rotation of our planet results in daily changes in light and darkness, as well as seasons with characteristic photoperiods. Adaptation to these daily and seasonal changes in light properties (and associated changes in the environment) is important to the sustained survival of higher life forms on our planet. Many organisms use their intrinsic circadian oscillator or clock to orchestrate daily rhythms in behaviour and physiology to adapt to diurnal changes. Some higher organisms use the same oscillator to monitor day length in selecting the appropriate season for reproductive behaviour. Organisms have developed irradiance measurement mechanisms to ignore photic noise (lightning, moonlight), and use the light of dusk and dawn for circadian photoentrainment. They have also devised multiple photoreceptors and signalling cascades to buffer against changes in the spectral composition of natural light. The interaction of the clock with ambient light is, therefore, quite intricate.
我们星球的自转导致了昼夜的日常变化以及具有特定光周期的季节变化。适应这些光特性的日常和季节变化（以及相关的环境变化）对于地球上高等生命形式的持续生存至关重要。许多生物体利用其内在的昼夜节律振荡器或生物钟来协调行为和生理上的日常节律，以适应昼夜变化。一些高等生物利用同一个振荡器来监测白昼长度，从而选择合适的繁殖行为季节。生物体已经发展出辐照度测量机制，以忽略光噪声（闪电、月光），并利用黄昏和黎明的光线进行昼夜光同步化。它们还设计了多种光感受器和信号级联反应，以缓冲自然光光谱组成的变化。因此，生物钟与环境光的相互作用相当复杂。
