Ravikumar G, Tewary P D
Centre of Advanced Study in Zoology, Banaras Hindu University, Varanasi, India.
Chronobiol Int. 1990;7(3):187-91. doi: 10.3109/07420529009056974.
Groups of photorefractory female subtropical house sparrows, Passer domesticus, when treated with 6 weeks of a short photocycle (8L:16D) showed significant ovarian growth on their return to a long photocycle (15L:9D). A 6-hr photophase coupled with scotophase of varying durations does not terminate the refractory period under photoperiod cycles of 12 (6L:6D), 36 (6L:30D) and 60 (6L:54D) hr but the refractory period is terminated by light-dark cycles of 24 (6L:18D), 48 (6L:42D) and 72 (6L:66D) hr. These results are consistent with the Bünning hypothesis of coincidence between endogenous photosensitive rhythmicity and environmental photoperiod timing that an endogenous circadian rhythm is involved in the maintenance and termination of photorefractoriness.
将处于光不应期的亚热带家麻雀（Passer domesticus）雌性群体，在经历6周短光照周期（8小时光照：16小时黑暗）处理后，当恢复到长光照周期（15小时光照：9小时黑暗）时，其卵巢出现显著生长。在12小时（6小时光照：6小时黑暗）、36小时（6小时光照：30小时黑暗）和60小时（6小时光照：54小时黑暗）的光周期循环下，6小时的光照期与不同时长的黑暗期相结合并不会终止光不应期，但24小时（6小时光照：18小时黑暗）、48小时（6小时光照：42小时黑暗）和72小时（6小时光照：66小时黑暗）的明暗循环会终止光不应期。这些结果与Bünning关于内源性光敏节律与环境光周期时间巧合的假说一致，即内源性昼夜节律参与了光不应期的维持和终止。
