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| Titel: |
Phases of photosensitivity in the circadian rhythms of coturnix quail |
| Auteur: |
Cain, J. R. Wilson, W. O. |
| Verschenen in: |
Biological rhythm research |
| Paginering: | Jaargang 2 (1971) nr. 4 pagina's 427-436 |
| Jaar: |
1971-12 |
| Inhoud: |
The photoperiodic induction of gonadal growth in coturnix (Japanese quail) was studied in relation to the existence of a daily photosensitive phase. A cycle of 14 hrs of dim green light and 10 hrs of darkness was used to synchronize activity rhythms of three groups of birds. In addition to this treatment, the second group of quail received a 3-hr pulse of white light at the beginning of the green phase, and another group was given a 3-hr light pulse at the end of the green phase. A fourth group was maintained in total darkness for 16 weeks. The control group for each experiment was given 14 hrs of white light and 10 hrs of darkness daily. Control birds reached sexual maturity before 8 weeks of age. Some quail kept in total darkness were sexually mature by 10 weeks of age. Significant differences in sexual maturation were not apparent among the three groups of birds receiving 14 hrs of dim green light daily, two of which were given white light pulses either at the beginning or at the end of the green phase, although a trend favored the group with early light Even though in adolescent quail gonadal growth was not markedly stimulated by the iight pulse given at the end of the green phase, the rate of egg production was maintained at a high rate for a longer period of time in mature laying females kept under these conditions than in the other treatments. This suggests that separate mechanisms exist in the interaction of light and the hypothalamus-pituitary-gonad system in maturation and maintenance processes. Brief photostimulation at the end of the daily activity period has been demonstrated by others to be sufficient to stimulate gonadal recrudescence in house sparrows. This exemplifies another difference between the responses of wild and domesticated birds. |
| Uitgever: |
Taylor & Francis |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
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