Gemmell R T, Sernia C
Department of Anatomy, University of Queensland, Brisbane, Australia.
J Reprod Fertil. 1992 Aug;95(3):701-8. doi: 10.1530/jrf.0.0950701.
The role of photoperiod on the initiation of the breeding season of brushtail possums was investigated in possums housed in three light regimens: a short-day, a natural and a long-day photoperiod. Seven possums were housed in a natural photoperiod. Four possums were transferred to a short-day photoperiod (10 h light, 14 h dark) and eight possums to a long-day photoperiod (14 h light, 10 h dark) on 22 November, when the daylength was 13.34 h. The first rises in plasma progesterone concentrations were observed on 9 January +/- 9 days (n = 4), 11 March +/- 6 days (n = 7) and 6 May +/- 6 days (n = 8), for possums held in short-day, natural or long-day photoperiods respectively. Similarly, births were observed on 12 January and 14 February in the short-day group, from 3 March to 8 May for the natural photoperiod group, and from 5 May to 8 August for the long-day group. These results suggest that photoperiod is important in the timing of the breeding season. However, annual breeding will commence in a nonstimulatory long-day photoperiod. Thus a long-day photoperiod does not prevent breeding activity.
在三种光照方案下饲养的帚尾袋貂中，研究了光周期对其繁殖季节开始的作用：短日照、自然日照和长日照光周期。七只袋貂饲养在自然光照周期下。11月22日，当日长为13.34小时时，四只袋貂被转移到短日照光周期（10小时光照，14小时黑暗），八只袋貂被转移到长日照光周期（14小时光照，10小时黑暗）。分别在短日照、自然日照或长日照光周期下饲养的袋貂中，首次观察到血浆孕酮浓度升高的时间为1月9日±9天（n = 4）、3月11日±6天（n = 7）和5月6日±6天（n = 8）。同样，短日照组在1月12日和2月14日观察到分娩，自然光照周期组在3月3日至5月8日观察到分娩，长日照组在5月5日至8月8日观察到分娩。这些结果表明，光周期对繁殖季节的时间安排很重要。然而，在非刺激性的长日照光周期下，年度繁殖仍会开始。因此，长日照光周期并不会阻止繁殖活动。
