據(jù)英國《新科學家》周刊網(wǎng)站報道,，經(jīng)過７０多年的研究，植物學家可能已發(fā)現(xiàn)激發(fā)植物開花的分子指令,。在全球變暖導致氣候帶向兩極移動的趨勢下,，這一發(fā)現(xiàn)對科學家?guī)椭魑镞m應不同緯度具有重要意義。
由德國科隆馬克斯·普朗克研究所的喬治·庫普蘭和倫敦帝國學院的科林·特恩布爾領導的小組發(fā)現(xiàn),，一種被稱為ＦｌｏｗｅｒｉｎｇＬｏｃｕｓ（ＦＴ）的基因所產(chǎn)生的蛋白質可以激發(fā)植物開花,。
研究人員利用基因工程把ＦＴ基因的蛋白質加入到擬南芥的綠色熒光蛋白質標記中，隨后把一種缺乏ＦＴ基因從而不能開花的突變莖嫁接到這種帶有標記的作物上,。結果發(fā)現(xiàn),，發(fā)光的ＦＴ蛋白質進入突變的莖，并促使其開花,。
另一支由日本人領導的小組利用大致相同的技術,，在水稻上顯示了同樣的過程。
專家認為，在兩種遠緣植物上發(fā)現(xiàn)相同的“促花素”,，表明所有植物的機理是一樣的,。
研究人員早在上世紀３０年代就發(fā)現(xiàn)，植物的葉子通過感應日光變化判斷季節(jié),，到時機成熟時,，就向莖尖發(fā)出某種信號，激發(fā)開花,。但是科學家始終不知道這種所謂“促花素”究竟是何種物質,。
英文原文：
Botanists discover the signal that triggers flowering
12:48 20 April 2007
NewScientist.com news service
Bob Holmes
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
