photoperiodism

[ foh-tuh-peer-ee-uh-diz-uhm ]

noun

, Biology.

1. the response, as affecting growth or reproduction, of an organism to the length of exposure to light in a 24-hour period.

photoperiodism

/ ˌfəʊtəʊˈpɪərɪəˌdɪzəm /

noun

1. the response of plants and animals by behaviour, growth, etc, to photoperiods

photoperiodism

/ fō′tō-pîr′ē-ə-dĭz′əm /

1. The response of an organism to changes in its photoperiod, especially as indicated by vital processes. For example, many plants exhibit photoperiodism by flowering only after being exposed to a set amount of daylight, as by requiring either a long or short day to flower. Plant growth, seed germination, and fruiting are also affected by day length. Photoperiodic responses in plants are regulated by special pigments known as phytochromes . In animals, migration, mating, amount of sleep, and other behaviors are also photoperiodic. In many animals, photoperiodism is regulated by the hormone melatonin .

Word History and Origins

Origin of photoperiodism¹

First recorded in 1915–20; photoperiod + -ism

Example Sentences

He was the co-discoverer of photoperiodism, the mechanism that dictates how sunlight triggers the blossoming of plants.

From Washington Post

We are wandering here from the Nordic wildflower meadow to the university laboratory and the study of photoperiodism.

From New York Times

But if one wanted to explain these data by building a formal/conceptual or mathematical model this could easily get mind-bogglingly complicated: one would have to take into account multiple feedback loops between repeatedly desynchronized oscillators, plus potential effects of photoperiodism.

From Scientific American

Most organisms use their circadian clocks to measure the changes in daylength through a mechanism called photoperiodism.

From Scientific American

Importantly, some of the genes involved in photoperiodism and flowering are intricately connected to the clock and may be a part of some of the clock feedback loops.

From Scientific American