- the interval in a 24-hour period during which a plant or animal is exposed to light.
Origin of photoperiod
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Examples from the Web for photoperiod
In general, Tb's showed a marked circadian cycle in phase with photoperiod.
Broad limits to functional reproductive activity seem to be set by the photoperiod—neuroendocrine system.The Breeding Birds of Kansas
Richard F. Johnston
These captives had been kept for several months at a temperature of 21 degrees Centigrade, and on a daily photoperiod of 15 hours.
The mice were kept in a room in which temperature and photoperiod were controlled.
- the period of daylight in every 24 hours, esp in relation to its effects on plants and animalsSee also photoperiodism
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
- The duration of an organism's daily exposure to light, considered especially with regard to the effect of such exposure on growth and development.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
- The duration of an organism's daily exposure to light, considered especially with regard to the phenomena of photoperiodism.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.