photoperiod

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photoperiod

 [fo´to-pēr″e-od]
the period of time per day that an organism is exposed to daylight (or to artificial light). adj., adj photoperiod´ic.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

photoperiod

(fō′tō-pîr′ē-əd)
n.
The daily duration of light and dark to which an organism is exposed, considered especially with regard to its effect on growth and development.

pho′to·pe′ri·od′ic (-ŏd′ĭk) adj.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

photoperiod

the length of daylight as compared with the length of darkness in each 24 hour cycle. see PHOTOPERIODISM.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005
References in periodicals archive ?
Studies examining the photoperiodic response of gene expression rhythms within the SCN have found results similar to those detailing the response of rhythms in firing rate.
Our study showed that the administration of endotoxin induced stress response in animals regardless of the photoperiodic conditions because the elevated cortisol concentration was determined in blood of all LPS-treated ewes.
Notably, six of seven actin variations, a gene traditionally used for normalization in QPCR analysis, exhibit an absolute fold change [greater than or equal to]1.3-fold over tidal conditions and four of seven display a variation [greater than or equal to]1.1-fold over photoperiodic conditions.
Social, but not photoperiodic, influences on reproductive function in male Peromyscus aztecus.
It seems clear that the historical migration of Cannabis throughout much of the world for purposes of cultivation was accompanied by strong selection for local photoperiodic regime.
Photoperiodic induction in vitro:The dynamics of GnRH release from hypothalamic explants of the Japanese quail.
Differential behavior of spinach explants and cultivars for callus induction on 2,4-D in response to photoperiodic alterations and calli characterization: Explant age showed significant difference in response for callus induction and 15 days old explants induced more calli compared with 7 days old explants (Data shown for15 days old explants only).
Photoperiodic control of the rat pineal arylalkylamine-N-acetyltransferase and hydroxyindole-O-meth-yltransferase gene expression and its effect on melatonin synthesis.
Dragon fruit is considered photoperiodic. That means its flowering is affected by the length of darkness.
Sangwan, "Effect of different photoperiodic regimes-on growth, flowering and essential oil in Mentha species," Plant Growth Regulation, vol.
In some plants, vernalization alone is sufficient for flowering evocation, but others require subsequent exposure to inductive photoperiods (usually long days), and in them the changes at the apex wrought by vernalization and the photoperiodic stimulus are presumably different, possibly complementary [33].