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MIND GAMES. "When Arabidopsis plants were exposed to a range of these atypical light–dark cycles, floral responses were not determined by the number of light or dark hours within a cycle but reflected how much transcription of the clock-controlled gene CO coincided with light." https://lnkd.in/d_f7kfY View in LinkedIn

ENTRAINMENT. "One of the fundamental properties of the circadian clock is that it will advance or delay its phase (that is, shift its rhythm forward or back relative to dawn and dusk) when entrained to light–dark cycles that are either longer or shorter than 24 h, respectively." https://lnkd.in/d_f7kfY View in LinkedIn

MUTANTS. "Abnormal function of the circadian clock in Arabidopsis mutants was correlated with defective floral responses to photoperiod. For example, the short-period mutant timing of cab 1-1 (toc1-1) flowered earlier than wild-type under short day conditions, whereas the long-period mutant zeitlupe (ztl) exhibited delayed flowering under long day conditions." https://lnkd.in/d_f7kfY View in LinkedIn

FAR-RED LIGHT. "A circadian rhythm in light sensitivity in constant light can be seen when far-red light is added to a background of white fluorescent or red light indicating that the rhythm in light sensitivity continues to run in constant light." https://lnkd.in/d_f7kfY View in LinkedIn

REDUCED SENSITIVITY. "For long day plants or light-dominant plants the situation is not quite as straightforward. Because sensitivity to night breaks is much reduced, it is very difficult to do night break experiments. Rhythms in response to an night break have been described in the long day plants but the pattern of response varies with the duration of the experimental dark period suggesting an interaction with the subsequent light period." https://lnkd.in/d_f7kfY View in LinkedIn

SENSITIVE WINDOW. "Light received during the photoinducible phase (dawn or an night break) prevents the short day response. Thus it is easy to think that the circadian rhythm in light sensitivity provides the timing base that allows the length of the dark period to be distinguished by the plant." https://lnkd.in/d_f7kfY View in LinkedIn

DUSK SIGNAL. "Short day plants often exhibit a qualitative requirement for inductive photoperiods and can frequently be induced to flower in response to a single inductive light–dark cycle. In such plants the circadian rhythm of responsiveness to night breaks is entrained by the dusk signal, so that the photoinducible phase always occurs at about the same time in darkness." https://lnkd.in/d_f7kfY View in LinkedIn

NIGHT BREAKS. "Responsiveness to night breaks was rhythmic in short day species and oscillated with a period of approximately 24 h. Results obtained with long day plants also supported this model, but suggested that the characteristics of the interaction of light and circadian rhythms were not the same in short day plants and long day plants." https://lnkd.in/d_f7kfY View in LinkedIn

"THE TIMING MECHANISM used in photoperiodism seems in most cases to be based on endogenous circadian rhythms in light sensitivity, as first postulated by Bunning (1936). He suggested that the circadian clock consisted of two half cycles, photophil and scotophil. When light was received in the scotophilic phase, the daily cycle was perceived as an long day, but the absence of light during the scotophilic phase produced an short day response. Support for these circadian clock-based models was initially provided by physiological studies." https://lnkd.in/d_f7kfY View in LinkedIn

ENTRAINMENT BY PHOTORECEPTORS. "Synchronization of circadian clocks to light–dark cycles (often described as entrainment) is mediated by the action of multiple photoreceptors. In Arabidopsis, this includes at least four of the five phytochromes." https://lnkd.in/d_f7kfY View in LinkedIn