Plant Biological Clocks–Help Them Prepare for the Day
When the alarm goes off, many people hit the snooze button. But eventually they get up and go to work or school.
Most plants, too, have an alarm clock. In fact, one of several such clocks goes off every morning. Circadian–or biological–clocks have a 24–hour cycle and "wake up" the processes that make plants operate properly. Circadian rhythms are common to all eukaryotic life. Your pulse, blood pressure, temperature, rate of cell division, blood cell count, alertness, urine composition, metabolic rate, and response to medications all fluctuate in a circadian manner.
Plants contain photoreceptors which are able to detect and gauge how much light is present. It tells the plant the time of the day, records the passage of time and report the seasons. Cellular responses are hence regulated with respect to the time of the day, depending on whether the photoreceptors are switched on or off . Here we shall look at a type of photoreceptor that regulates most of the plants’ cellular processes, the phytochrome.