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Biological Clock Found in Plants
Joe the Lesser writes "This CNN article discusses how scientists have found that a chemical 'clock' that tells a plant to prepare for the sun. The clock controls an enzyme that modifies a protein called D1. This protein is critical for photosynthesis, the process whereby plants extract light and convert it to food. When D1 binds with phosphorus, it creates a modified protein found in chloroplast -- a special structure in the cell that's made of carbohydrates, fat and proteins."
Of course plants have a biological clock. That's why I switched to boxers.
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J. Green Giant
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The lady plants'll start really going on the prowl at about 33 or so...
Why is it that an article discovery about this 'clock' system in plants seems to be more a description of photosynthesis (which is fairly well understood, if I remember my highschool biology correctly) than the newly discovered clock?
Maybe they just don't know how the clock works yet, but it would be nice to have more information about the nature of the clock than a explaination of photosynthesis. I know that that photosynthesis is worked in because the clock has an effect on it, but is that really the real story? It isn't IMHO.
"Karma can only be portioned out by the cosmos." -- Homer Simpson
I wonder if this has anything to do with how old a plant will become. Maybe if they can control its biological clock, they can extend the days of that plant.
...they could find a way to get this to apply to humans. Like a nightly pill. If it's naturally made by plants, it could be cheaper than sythetic and it could make the alarm clock obsolete.
Only in slashdot are posts of solidarity modded at -1 Redundant, while posts of antagonism are modded as -1 Flamebait.
There may not be an actual use for this protein for us, but it may give us a better understanding of the mechanism by which it works. A novel mechanism may give us a better understanding of some interactions in our own body, even if the pathways may not be directly related in function.
link2paper
Phosphorylation of the D1 Photosystem II Reaction Center Protein Is Controlled by an Endogenous Circadian RhythmIsabelle S. Booij-James, W. Mark Swegle, Marvin Edelman, and Autar K. Mattoo*
Vegetable Laboratory, The Henry A. Wallace Beltsville Agricultural Research Center-West, United States Department of Agriculture-Agricultural Research Service, Beltsville, Maryland 20705-2350 (I.S.B.-J., M.S., A.K.M.); and Department of Plant Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel (M.E.)
The light dependence of D1 phosphorylation is unique to higher plants, being constitutive in cyanobacteria and algae. In a photoautotrophic higher plant, Spirodela oligorrhiza, grown in greenhouse conditions under natural diurnal cycles of solar irradiation, the ratio of phosphorylated versus total D1 protein (D1-P index: [D1-P]/[D1] + [D1-P]) of photosystem II is shown to undergo reproducible diurnal oscillation. These oscillations were clearly out of phase with the period of maximum in light intensity. The timing of the D1-P index maximum was not affected by changes in temperature, the amount of D1 kinase activity present in the thylakoid membranes, the rate of D1 protein synthesis, or photoinhibition. However, when the dark period in a normal diurnal cycle was cut short artificially by transferring plants to continuous light conditions, the D1-P index timing shifted and reached a maximum within 4 to 5 h of light illumination. The resultant diurnal oscillation persisted for at least two cycles in continuous light, suggesting that the rhythm is endogenous (circadian) and is entrained by an external signal.
...is how I read this headline.
"America, I smoke marijuana every chance I get."
a certain plant gets very nervous at 4:20
This lobster was alive when it hit the frothy, boiling water.
really
The plant ageing clock is the same as the human ageing clock; it's based on something called "the Hayflick limit", which is the limit on the number of times a cell can divide.
You can look it up on the web, but the short version is that each time a cell divides, it shortens the telomeres on the ends of its genes; when it runs out of telomeres, the cell dies (or becomes cancerous, or is subject to other age-related disease processes).
Baby humans and plants don't have this limit, since, in gametogenesis, the telomeres are lengthened by a chemical called "telomerase", effectively resetting the clock for the newly created entity.
-- Terry