photorefractoryadj.
/ˌfəʊtə(ʊ)rᵻˈfrakt(ə)ri/, U.S. /ˌfoʊdərəˈfrækˌtɔri/, /ˌfoʊdəriˈfrækˌtɔri/ Zoology and Ecology.
Unresponsive to photoperiods, or changes in photoperiod, that normally elicit physiological or behavioural changes; characterized by such unresponsiveness.
ΚΠ
1959 W. L. Engels in R. B. Withrow Photoperiodism 763 The results of the first experiments..indicate a photorefractory phase which is maintained for at least 8½ months by 14-hr photoperiods.
1963 Ecology 44 519/2 The birds are photorefractory, as revealed both by their lack of metabolic response when subjected to prolonged artificial photoperiods..and by the state of the hypothalamic neurosecretory system.
1984 Jrnl. Endocrinol. 97 253 Previous studies have shown that an increase in prolactin secretion coincides with the beginning of the photorefractory phase in starlings.
2002 Proc. National Acad. Sci. U.S.A. 99 16291 (title) Hypothalamic gene expression in reproductively photoresponsive and photorefractory Siberian hamsters.
Derivatives
ˌphotoreˈfractoriness n. the condition of being photorefractory.
ΚΠ
1959 W. L. Engels in R. B. Withrow Photoperiodism 764 Complete release from photorefractoriness had not in fact occurred during the period of short days.
1982 Proc. Royal Soc. B. 215 96 Classically, photorefractoriness is characterized by birds passing from a state of ‘absolute’ refractoriness, when their ability to respond photoperiodically is totally lost, through a state of ‘relative’ refractoriness when they will respond to quite long daylengths.
2004 Gen. & Compar. Endocrinol. 137 99 In this study, we tested for photo-induction of reproductive development and photorefractoriness in males of three cardueline finch species.
This is a new entry (OED Third Edition, March 2006; most recently modified version published online March 2022).
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adj.1959