Search results
Results from the WOW.Com Content Network
Linnaeus's flower clock was a garden plan hypothesized by Carl Linnaeus that would take advantage of several plants that open or close their flowers at particular times of the day to accurately indicate the time. [1] [2] According to Linnaeus's autobiographical notes, he discovered and developed the floral clock in 1748. [3]
In plant biology, nyctinasty is the circadian rhythm-based nastic movement of higher plants in response to the onset of darkness, or a plant "sleeping". Nyctinastic movements are associated with diurnal light and temperature changes and controlled by the circadian clock .
A better understanding of plant circadian rhythms has applications in agriculture, such as helping farmers stagger crop harvests to extend crop availability and securing against massive losses due to weather. Light is the signal by which plants synchronize their internal clocks to their environment and is sensed by a wide variety of photoreceptors.
The conception of the plant biological clock as made up of interacting negative feedback loops is unique in comparison to mammal and fungal circadian clocks which contain autoregulatory negative feedback loops with positive and negative elements [6] (see "Transcriptional and non-transcriptional control on the Circadian clock page).
Many plants exhibit certain behaviors at specific times of the day; for example, flowers that open only in the mornings. Plants keep track of the time of day with a circadian clock. [6] This internal clock is synchronized with solar time every day using sunlight, temperature, and other cues, similar to the biological clocks present in other ...
The best studied rhythm in chronobiology is the circadian rhythm, a roughly 24-hour cycle shown by physiological processes in all these organisms. The term circadian comes from the Latin circa, meaning "around" and dies, "day", meaning "approximately a day." It is regulated by circadian clocks.
The uniform alignment of the flowers does result from heliotropism in an earlier development stage, the bud stage, before the appearance of flower heads. The apical bud of the plant will track the Sun during the day from east to west, and then will quickly move west to east overnight as a result of the plant's circadian clock. [11]
In 1936, Bünning published his model for plant photoperiodism, wherein he proposed that endogenous (internal) circadian rhythms enable plants to measure day length. Bünning's model of photoperiodism would go largely unnoticed by the scientific community until 1960 when he chaired the 1960 Cold Spring Harbor Symposium on Biological Clocks.