This Article Full Text (PDF) References Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Saved Citations Download to citation manager Request Permissions Request Reprints Add to My Marked Citations Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Citing Articles via Scopus Google Scholar Articles by Kumar Maitra, S. Articles by Dey, M. Search for Related Content PubMed PubMed Citation Articles by Kumar Maitra, S. Articles by Dey, M. Social Bookmarking                         What's this?

Importance of Photoperiods in Determining Temporal Pattern of Annual Testicular Events in Rose-Ringed Parakeet (Psittacula krameri )

Department of Zoology, University of Burdwan, Golapbag, Burdwan 713 104, India

Mamata Dey

Department of Zoology, University of Burdwan, Golapbag, Burdwan 713 104, India

Male rose-ringed parakeets (Psittacula krameri) were transferred to a long photoperiod (LP; LD 16:8) or a short photoperiod (SP; LD 8:16) for 45 or 90 days on four dates corresponding to the beginnings of different reproductive phases in an annual testicular cycle, and testicular responsiveness was evaluated by comparison with the testicular volume, weight, seminiferous tubular diameter, and germ cell profiles of birds in a natural photoperiod (NP). Exposure of birds to LP during the progressive phase (November) led to precocious maturation of testes after 45 days, but induced regression at 90 days. After showing retarded gametogenic functions at 45 days, parallel (November) SP birds exhibited an accelerated rate of germ cell formation at day 90. During the prebreeding phase (January), there were no remarkable differences in any features of testes among NP, LP, and SP birds at 45 days, but gonadal involution in LP parakeets and active spermatogenesis in SP birds occurred after 90 days. The testes did not show any response to LP or SP for 45 and 90 days when the birds were transferred to altered photoperiods during the breeding (March) and preparatory (June) phases, indicating that the parakeets were photorefractory for at least 6 months (March through September). The results also suggest that initiation and termination of seasonal gametogenic activity in parakeets are possibly functions of endogenous rhythmicity or extraphotoperiodic environmental factors. Duration of light may have certain influences on the attainment of annual peak in spermatogenesis, but in all probability the species has a low photoperiod threshold for induction of testicular growth.

Key Words: annual cycle • photoperiod • rose-ringed parakeet • testis

Journal of Biological Rhythms, Vol. 7, No. 1, 13-25 (1992)
DOI: 10.1177/074873049200700102


CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				R. Dey, S. Bhattacharya, and S. K. Maitra Importance of Photoperiods in the Regulation of Ovarian Activities in Indian Major Carp Catla catla in an Annual Cycle J Biol Rhythms, April 1, 2005; 20(2): 145 - 158. [Abstract] [PDF]