/foh'teuh pear"ee euh diz'euhm/, n. Biol.the response, as affecting growth or reproduction, of an organism to the length of exposure to light in a 24-hour period. Also called photoperiodicity /foh'toh pear'ee euh dis"i tee/.[1915-20; PHOTOPERIOD + -ISM]
* * *Response by an animal or plant to changes in daily, seasonal, or yearly cycles of light and darkness.Among animals, sleep, migration, reproduction, and the changing of coats or plumage are regulated to some extent by day length. In the poultry industry, photoperiodism is commonly induced by artificial lighing to maximize egg laying and body weight. Plant growth, seed setting, germination, flowering, and fruiting are also affected by day length. Other environmental factors that modify an organism's responses include temperature and nutrition.
* * *▪ biologythe functional or behavioral response of an organism to changes of duration in daily, seasonal, or yearly cycles of light and darkness. Photoperiodic reactions can be reasonably predicted, but temperature, nutrition, and other environmental factors also modify an organism's response.In animals, the regular activities of migration, reproduction, and the changing of coats or plumage can be induced out of season by artificially altering daylight. Birds, for example, have migrated north in the winter after having been exposed to reversed seasonal lighting in laboratories. The manipulation of a specific stimulating period of darkness, which is required by each species for every phase of the migratory process, is an important factor in photoperiodism.When stimulated by light, an animal's pituitary gland will release hormones that affect reproduction. Thus, the mating season of a species can be made to occur at an unusual time by manipulating daylight. Long periods of light followed by short periods will induce mating behaviour in species that normally breed in autumn (e.g., goats and sheep), while spring breeders (e.g., mink) will start the reproductive process when daylight is increased. Application of photoperiodism is common in the poultry industry, as daylight affects egg-laying, mating, and body weight of the fowl.
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Photoperiodism — is the physiological reaction of organisms to the length of day or night. It occurs in plants and animals. Contents 1 In plants 1.1 Long day plants 1.2 Short day plants 1.3 … Wikipedia
photoperiodism — photoperiodism. См. фотопериодизм. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) … Молекулярная биология и генетика. Толковый словарь.
photoperiodism — 1920, from photoperiod (1920), from PHOTO (Cf. photo ) + PERIOD (Cf. period) … Etymology dictionary
photoperiodism — [fōt΄ō pir′ēə dis′ə tēfōt΄ō pir′ē əd iz΄əm] n. Biol. the behavioral or physiological reaction of an organism to variations in the duration of light, as, in plants, by flowering or ceasing to flower, or, in certain animals, by changing the daily… … English World dictionary
photoperiodism — fotoperiodizmas statusas T sritis ekologija ir aplinkotyra apibrėžtis Augalų vystymosi priklausomybė nuo dienos ir nakties ilgumo santykio. atitikmenys: angl. photoperiodism vok. Photoperiodismus, m rus. фотопериодизм, m … Ekologijos terminų aiškinamasis žodynas
photoperiodism — fotoperiodizmas statusas T sritis augalininkystė apibrėžtis Genetiškai reguliuojama organizmų reakcija į paros šviesos (dienos ir nakties ilgio santykio) kitimą. atitikmenys: angl. photoperiodism rus. фотопериодизм ryšiai: sinonimas – šviesoveika … Žemės ūkio augalų selekcijos ir sėklininkystės terminų žodynas
photoperiodism — noun Date: circa 1911 a plant or animal s response or capacity to respond to photoperiod … New Collegiate Dictionary
photoperiodism — Events triggered by duration of illumination or pattern of light/dark cycles: often the wavelength of the illuminating light is important as for example in control of circadian rhythm in plants. See phytochromes … Dictionary of molecular biology
photoperiodism — noun the growth, development and other responses of plants and animals according to the length of day and/or night See Also: photoperiodic … Wiktionary
photoperiodism — The periodic (seasonal or diurnal) activities, behavior, or changes in plants or animals brought about by the action of light. * * * pho·to·pe·ri·od·ism pir ē ə .diz əm also pho·to·pe·ri·od·ic·i·ty .pir ē ə dis ət ē n, pl isms also ties the… … Medical dictionary