What triggers flower?

[Green Supreme]

Just something I found on the web. Peace GS

http://www.newscientist.com/article/dn11674-botanists-discover-the-signal-that-triggers-flowering.html

[The Cannarchist]

^^^^^^^


After a quest lasting more than 70 years, botanists may finally have found what one leading textbook describes as "the Holy Grail of plant biology" – the molecular command that tells a plant it is time to flower.

The discovery may help scientists tailor crops to different latitudes – an especially valuable ability as global warming begins to shift climate zones towards the poles.

Researchers have known since the 1930s that the leaves of plants perceive the seasons by sensing the amount of daylight and, when the time is right, trigger flowering by sending some sort of signal to the shoot tip. But the identity of this so-called "florigen" has remained mysterious.

Now two research teams have independently identified it. Florigen, they say, is the protein produced by a gene called Flowering locus T, or FT. One team, led by George Coupland at the Max Planck Institute for Plant Breeding Research in Cologne, Germany, and Colin Turnbull at Imperial College London in the UK, used genetic trickery to join the FT protein to a green fluorescent protein marker in Arabidopsis, or thale cress.

Green fuse
Onto this marker-enriched plant, the team grafted a mutant stem that lacked the FT gene and so was unable to flower by itself. They observed that the fluorescent FT protein crossed into the mutant stem and triggered flowering. "It's pretty unambiguous," says Turnbull.

Another team, led by Ko Shimamoto at the Nara Institute of Science and Technology in Ikoma, Japan, used much the same technique to show the same thing in rice.

Finding the same florigen in two such distantly related species suggests the mechanism is common to all plants, says Jan Zeevaart, a plant biologist at Michigan State University in East Lansing, US.

The new results are not the FT gene's first turn in the limelight. In recent years, several studies have shown that FT is turned on in leaf tissue at particular day lengths, and that the FT protein acts in the shoot tip to trigger flowering. However, no one knew whether the FT protein or some other molecule was the flowering signal that shuttled from leaf to shoot tip.

Messenger shot
In 2005, researchers in Sweden seemed to settle the question when they announced that messenger RNA from the FT gene was the mobile signal. But this week, the Swedish team formally retracted this claim.

"A guest researcher from China who had been invited to join our team manipulated the data to get false results," says Ove Nilsson at Umeå University in Sweden. The Chinese researcher, Tao Huang, who is no longer at Umeå University, still stands by his results, says Nilsson.

With the flowering signal now firmly in hand, biotechnologists have the means to tinker with a plant's flowering time to adapt it to different conditions. For example, farmers at higher latitudes might want to force crops to flower earlier so that they can mature their fruit before the first frost, suggests Brian Ayre, a plant biologist at the University of North Texas in Denton, US.

Reference: Science, doi:10.1126/science.1141752 and doi:10.1126/science.1141753; (retraction) Science, vol 316, p 367

[Green Supreme]

You callin me lazy? Teehee. Peace GS

[Green Supreme]

Now all of you, off to manipulate to our advantage. Peace GS

[The Cannarchist]

I wonder if C-ray could make that?.......:wagass:

[Green Supreme]

C-ray is that:cool2:

[c-ray]

florigen proteodies anyone?

[Green Supreme]

Man to be able to star flower in the midst of the hottest most intense months, would improve quality exponentially. Peace GS

[nuggdigger]

Recent work has implicated two genes, FT and CO, as possible components of the florigen signal.


Biologists finally close in on 'florigen,' the signal that causes plants to flower
FOR RELEASE: Sept. 30, 2004
Contact: Roger Segelken
Office: 607-255-9736
E-Mail: hrs2@cornell.edu

ITHACA, N.Y. -- Postdoctoral researcher Brian Ayre was listening attentively to a Cornell University seminar on flower development when he asked what seemed an obvious question: "What is the signal that controls flowering?" The seminar speaker laughed. "They've been trying to figure that out for a hundred years," he said. More laughter followed, as one of Ayre's colleagues shouted from the back of the room: "Florigen!"

No one's laughing now. Ayre, currently a faculty member at the University of North Texas, went on to publish a provocative report in the August 2004 issue of Plant Physiology along with his postdoctoral adviser Robert Turgeon, a Cornell professor of plant biology. Their paper recounts the serendipitous discovery that the plant protein, CONSTANS, may be the signal -- "florigen" -- that causes plants to flower. Or at least, the researchers say, CONSTANS plays an important role in generating the signal.

Trying to understand flowering is a popular pursuit because of its importance in agriculture. Flowers are the precursor of fruit, and if flowering can be controlled, plants can be manipulated to remain in a vegetative or flowering state. Accelerated flowering could lead to a much shorter growing season -- an important advance for both growers and plant breeders. And the significance for the floriculture industry is equally huge.

Textbooks predating the 1970s dedicated entire chapters to this elusive signal. More recently, though, florigen has become an example of a dead-end pursuit in plant biology -- one more likely to prompt sarcastic grins than scientific inquiry to find this crucial puzzle piece in the understanding of plant development.

Turgeon's research focus at Cornell is on understanding how molecules move in the phloem, the "bloodstream" of plants that carries food, nutrients and signaling molecules. When Ayre joined his group, they were by no means setting out to discover the signal that induces flowering.But as sometimes happens in science, "people from outside of the field end up making significant contributions because they have different tools and different perspectives," says Turgeon, picking up the story: "We were coming at the study from a transport perspective. We got into this when we got a hold of the promoter of the galactinol synthase gene, a genetic factor that drives expression of genes specifically in the vein of the leaf so that they can enter the phloem. I saw this as a tool to study the transport of large molecules through the phloem. Once we got the tool, we began to design experiments to use it. We applied it and got a very interesting result."

The researchers took two approaches that led them to the conclusion that CONSTANS is a signal involved in flowering. First, using Arabidopsis plants in which all CONSTANS protein had been abolished, they introduced a copy of the CONSTANS gene under the control of the galactinol synthase promoter, which causes the protein to be synthesized only in the leaf. Despite this precise expression pattern, they saw that the signal had a dramatic effect on flowering. This suggests that either CONSTANS is moved throughout the plant to the site of flowering through the phloem, or it interacts with another factor inside the phloem that is transported to the site of flowering.

They provided further evidence for CONSTANS' role in floral signaling when they grafted Arabidopsis plants that contained no CONSTANS protein onto plants synthesizing CONSTANS in their leaves. This elegant experiment showed that CONSTANS, or another factor that it interacts with, was able to move through the graft junction to signal flowering in the parts of the plant that formerly were devoid of any of the protein.

Turgeon credits the late Russian plant physiologist M.H. Chailakhyan for some of the earliest work in trying to understand the nature of the flowering signal. In 1937 Chailakhyan named and defined florigen as a graft-transmissible signal that induces flowering. Ayre's and Turgeon's work appears to fit this historical definition of the flowering hormone, they say.

However, it is not clear whether CONSTANS is in fact the flowering hormone. More likely, Ayre says, "It may be interacting with another downstream factor that moves to the site of flowering action. It is clear now that CONSTANS is an important factor in generating this signal."

Comments Jan Zeevaart, an emeritus professor of plant biology at Michigan State University who has dedicated much of his research career to florigen and other plant hormones: "It is gratifying to see that there are finally molecular approaches to the problem. For quite some time, some people have ridiculed the concept of florigen, but those of us who have worked on the physiological aspects always knew that it could not be dismissed so easily."

"The exciting thing is that it appears that people are finally closing in on the identity of florigen," Turgeon responds. Ayre adds: "I suspect that CONSTANS and downstream components, such as a protein called FT, are going to be pretty hot topics in the next couple of years."The article in Plant Physiology was titled "Graft Transmission of a Floral Stimulant Derived from CONSTANS." Ayre's and Turgeon's work was supported by the U.S. Department of Agriculture and the National Science Foundation.

At Cornell, Peter Davies, a professor in the Department of Plant Biology since 1969, has spent his career working on other plant hormones. Excited by the finding, he recently recalled a quotation from a fellow plant physiologist in the 1970s: "Flowering is a religion based on the totally unfounded dogma of florigen."

As it turns out, the "religion" may be about to get some new followers.


Related World Wide Web sites: The following sites provide additional information on this news release. Some might not be part of the Cornell University community, and Cornell has no control over their content or availability.


oTurgeon laboratory:

http://www.plantbio.cornell.edu/people.php?netID=ert2#research


This article was prepared by Sarah Nell Davidson, a graduate student in plant biology and science-writing intern in the Cornell News Service.

[nuggdigger]

This is a very interesting topic, I don't know much about genetics.
What I do know I learned from my father. He said frequently.." diarrhea is hereditary....it runs in your jeans"
So from my minimal knowledge of genetics learned at home,....well...chuckle..it sort of brings a new perspcetive to the question I wonder if cray could make that....lol...
just teazin bigC:laugh2:..you rule

peace;)

[justcurios]

i had always heard that hormones make a plant flower, and once they are activated, the plant continues to flower until it has reached the end of its life span. true or false.

[nuggdigger]

A hormone is any chemical produced in one part of the body that has a target elsewhere in the body. Plants have five classes of hormones. Animals, especially chordates, have a much larger number. Hormones and enzymes serve as control chemicals in multicellular organisms. One important aspect of this is the obtaining of food and/or nutrients.

auxins: A group of hormones involved in controlling plant growth and other functions; once thought responsible for phototropism by causing the cells on the shaded side of a plant to elongate, thereby causing the plant to bend toward the light.

gibberellins: A group of hormones that stimulate cell division and elongation in plants. Gibberellic acid (GA), the first of this class to be discovered, causes bolting (extreme elongation) of stems. GA is also applied to certain plants to promote larger fruits.

cytokinins: A group of hormones that promote cell division and inhibit aging of green tissues in plants.

abscisic acid: A plant hormone that promotes dormancy in perennial plants and causes rapid closure of leaf stomata when a leaf begins to wilt.

ethylene: A gaseous plant hormone that stimulates fruit ripening and the dropping of leaves.




photoperiodism: The ability of certain plants to sense the relative amounts of light and dark in a 24-hour period; controls the onset of þowering in many plants.

Photoperiodism is the plant response to the relative amounts of light and dark in a 24 hour period, and controls the flowering of many plants. Short-day plants flower during early spring or fall, when the nights are relatively longer and the days are relatively shorter. Long-day plants flower mostly in summer, when the nights are relatively shorter and the days are relatively longer. Day-neutral plants flower without respect for the day length. Phytochrome is a plant pigment in the leaves of plants that detects the day length and generates a response.

In a nut shell Dominance of auxins, gibberellins, and cytokins in a plant keeps the plant growing ina vegetative and youthful state. Ethylene and Abscisic adic in a plant lead to ageing and seed preparation.
Justcurious, your nutshell is to big for sumarization. I Could say both true and false and be correct. What's the false referto anyways?..lol

peace

[nuggdigger]

I suspect what were really talking about here is "SIGNAL" and how to manipulate it.

The leaves are the only part of the plant that carries the flowering signal, which triggers the hormones in the plant to alter their functions. The message is so subtle that if only a small piece of one single leaf is left on the plant, it will still sense the signal. Plants that have had all the leaves stripped will never receive the flowering message.
The mechanism that causes this flowering signal is a most astounding process. Plants contain very specific pigments, two of which that are responsible for the message called:
Phytochrome Red(PR): absorbs red light at 660-760 nm, and
Phytochrome Far Red(PFR): absorbs far red light at 760-800 nm.
These two photochemically reactive pigments act as "on-off" switches to the plant

How to Induce Flowering
The (PFR) is the active form of phytochrome that controls the flowering in plants.
Plants are continuously making PR, which degrades to PFR whenever it gets exposed to red light at 660-760nm. The PFR is the active ingredient in the plant. If a plant receives no light or is exposed to far red light at 760-800nm, PFR flips back to PR. The PR is a "nothing" condition. Here is an easy way to remember the process: PRF is rapidly produced in light, PR is slowly produced in dark.
During the daytime, the balance between PR and PFR is constant. When night comes, the darkness or far red light steadily decreases the PFR over a period of hours, causing the PR to rise. IF a flash light (with red in it) occurs in the middle of the night period or if the plant is exposed to daylight, the PR immediately changes to PFR, which is the active ingredient that switches OFF the flowering signal.The flowering signal can be turned ON again by pulsing the plant with a far red frequency, which again changes PFR to PR.

How a plant actually starts to flower outdoors is not understood yet, but gibberrellins are involved. It is probable that as the day periods shorten and the night periods lengthen and the PFR stays below a certain level for about 2 weeks, the gibberrellins and the other hormones subtly change in relation to one another. This changes the growing shoot to form flowers.
In short, the PFR is the biologically active pigment that turns on the flowering in long day flowering plants and turns off the flowering in short day plants. In the winter(short days), the PFR level gets low enough to trigger flowering in short day flowering plants. During the summer PFR is not low enough to signal flowering.

for above posts,NOTE: this particular post I was unable to obtain off the Internet. I did however pay for the book and am sharing the info purely for educational purposes. I hope that the Graham Reinders considers this a form of free advertising and promo, as How to Supercharge your Garden is after all a fantastical informative readable book that I would recommend to anyone.

Man to be able to star flower in the midst of the hottest most intense months, would improve quality exponentially. Peace GS

until now..In the winter(short days), the PFR level gets low enough to trigger flowering in short day flowering plants. During the summer PFR is not low enough to signal flowering.


Call it what you want...to me this is incredibly exciting news if we can crack this egg. :thumbsup:
But unfortunately, seems to lie in the realms of Genetic Modification:cry:
they introduced a copy of the CONSTANS gene under the control of the galactinol synthase promoter, which causes the protein to be synthesized only in the leaf. Despite this precise expression pattern, they saw that the signal had a dramatic effect on flowering. This suggests that either CONSTANS is moved throughout the plant to the site of flowering through the phloem, or it interacts with another factor inside the phloem that is transported to the site of flowering.

They provided further evidence for CONSTANS' role in floral signaling when they grafted Arabidopsis plants that contained no CONSTANS protein onto plants synthesizing CONSTANS in their leaves. This elegant experiment showed that CONSTANS, or another factor that it interacts with, was able to move through the graft junction to signal flowering in the parts of the plant that formerly were devoid of any of the protein.

Is grafting the poormans Genetic Modification kit?;)

peace:peace:

[justcurios]

good research nugg! i have also heard of triggering plants by inducing 12/12 lighting indoors for a couple weeks, and then setting them outdoors say in the begining of summer. this should make them flower all season, in theory , correct ?

[The Cannarchist]

Theory maybe....Practice No.The plants will start to re-veg in high summer.