Year: 2022

SEASONAL CUE. "Photoperiod alone is not an unambiguous signal as any particular daylength occurs twice in an annual cycle. Progressive changes in daylength, which are at their greatest around the equinoxes in spring and autumn, do, however, provide a certain environmental signal for the passage of the seasons." https://lnkd.in/d_f7kfY View in LinkedIn

RANGE. "The seasonal range and rate of change of daylength is lower in the tropics than at higher latitudes and photoperiodic mechanisms need to be sufficiently precise and flexible to operate across the entire range of daylengths." https://lnkd.in/d_f7kfY View in LinkedIn

DAYLENGTH SYNCHRONICITY. "Photoperiodic plants are common, even in tropical latitudes where the seasonal daylength changes are small, and daylength is used to synchronize reproductive or other activities with seasonal events such as dry or rainy periods. Coincident flowering in members of a population increases the chances of outbreeding and hence genetic recombination." https://lnkd.in/d_f7kfY View in LinkedIn

IN SPACE AND TIME. "Synchronization of floral initiation through photoperiodic sensitivity can confer advantages independently of whether reproduction is matched with a particular favourable environment. A further potential benefit of photoperiodic responses is that they can enable organisms to occupy an ecological niche in space and time." https://lnkd.in/d_f7kfY View in LinkedIn

PHOTOPERIODS TYPE PLANTS. "Short-day plants (SDPs) are those that flower or in which flowering is accelerated by days which are shorter than a critical daylength. Long-day plants (LDPs) are plants that flower or in which flowering is accelerated when the daylight period exceeds a critical daylength. Plants that flower at the same time irrespective of the photoperiodic conditions are called day-neutral plants (DNPs)." https://lnkd.in/d_f7kfY View in LinkedIn

OBLIGATE AND FACULTATIVE. "Plants that respond to daylength can be further subdivided into obligate (or qualitative) types, where a particular daylength is essential for flowering, or facultative (or quantitative) types, where a particular daylength accelerates but is not essential for flowering." https://lnkd.in/d_f7kfY View in LinkedIn

TENEBROPERIOD VS PHOTOPERIOD. "The length of the day and night are mutually linked within the 24-h daily cycle. Photoperiodic responses could therefore be theoretically determined by either the length of the day or the length of the night. Classic experiments with short day plant Xanthium revealed that flowering only occurred if the night length was greater than 8.5 h, irrespective of the relative durations of light and darkness in the experimental cycle." (Tenebris, latin for darkness). https://lnkd.in/d_f7kfY View in LinkedIn

SHORT DAYS "did not cause flowering if they were coupled with short nights but when the night was sufficiently long, flowering occurred even when the accompanying light periods were long. However, although a sufficiently long dark period appeared to be the decisive factor for flowering to occur, the level of flowering was also affected by the length of the light period." https://lnkd.in/d_f7kfY View in LinkedIn

NIGHT BREAKS. "If a long night is interrupted by a short (e.g. 30 min) period of light (or night break) near the middle, short day plants respond as if they have been exposed to an long day. For long day plants, such night breaks are only effective if given in combination with daylengths that are just longer than those needed to permit flowering or if they are of several hours duration." https://lnkd.in/d_f7kfY View in LinkedIn

DARK- AND LIGHT-DOMINANT. "Also, in long day plants, unlike in short day plants, the amount and spectral composition of the light given during the day period, especially in the latter part, has a large effect on flowering. If the response to daylength depends primarily on the length of the dark period, the plants are called dark-dominant and conversely, if the light period is the main influence, they are called light-dominant. In general, most short day plants are dark-dominant and most long day plants are light-dominant." https://lnkd.in/d_f7kfY View in LinkedIn