The science of spring: Plants rely on internal alarm clocks to tell them when to wake up from winter

Mar 21, 2011 By Katharine Gammon
In many regions, the blooming of daffodils marks the unofficial start of the spring season. Credit: ISNS

Just in time for the birds and the bees to start buzzing, the flowers and the trees somehow know when to open their buds or start flowering. But the exact way that plants get their wake-up call has been something of a mystery.

"Why should plants care?" The general answer to that is that there are a lot of situations where it’s important not to do something developmentally until spring has arrived," said Richard Amasino, a professor of biochemistry at the University of Wisconsin Madison. " want to make sure that their buds are protected until spring."

Sibum Sung, a molecular biologist at the University of Texas Austin has an idea of how this protective action works on a cellular level. He discovered a special molecule in plants that gives them the remarkable ability to recall winter and to bloom on schedule in the spring. Sung published his results last December in the journal Science Express.

While digging through the DNA of a small cabbage-like plant called Arabidopsis, Sung and a colleague discovered that the production of a special molecule could be turned on or off by a string of genetic material. When the plant gets cozy for the winter, this molecule is not produced, repressing a plant’s ability to create . But after 20 days of consistently frigid weather, production of the molecule gets turned back on, signaling another gene to stop repressing flower production and start preparing for spring. The plant takes another 10-20 days to prime itself for warmer temperatures. Without the 20 days of freezing temperatures, the molecule wouldn't be produced -- even if there is a brief spike in the thermometer reading.

Sung hypothesized that over millions of evolutionary years, this molecule -- called COLDAIR -- has created a sort of cellular memory in generations of plants, letting them know that a month of winter has come and gone, and now they can start preparing for the spring.

Of course, mysteries remain. Sung admits that his team is still working on questions like how the plant knows that temperatures have been low for at least 20 days.

"Well, we know that there are several things done by cold -- but how? That we don't really know yet," Sung said.

The genetic pathways involved are different for each type of plant, said Amasino, but the kind of alarm clock memory is similar. The reason may have to do with the early evolution of plants.

"Flowering plants had already evolved and changed 150 million years ago, when the Earth was a pretty different place," Amasino said. At that time, the Earth was much warmer, and the Atlantic Ocean didn't even exist yet. "So it's relatively recently that plants had to contend with winter," he said.

The kind of responses that plants developed to cold over the past hundred million years happened independently, said Amasino -- and that is one reason that different plants have unique systems to deal with wintertime. "One aim of plant research for the future is to explore how these systems evolved in different plant species," Amasino said.

When the planet’s climate changes more rapidly, it can sometimes be difficult for plants to keep up. Researchers have been studying plants that are opening earlier in the season, according to Ove Nilsson, a professor at the Umea Plant Science Centre in Umea, Sweden. He said that another problem with early spring is that plants get out of sync with their insect pollinators.

"This could potentially be catastrophic for the plants since these flowers can freeze to death," said Nilsson.

But as long as there is winter, nature will keep the pressure on to set an alarm clock for springtime, and the will once more open up.

Explore further: The anti-inflammatory factory

More information: Vernalization-Mediated Epigenetic Silencing by a Long Intronic Noncoding RNA, Science 7 January 2011: Vol. 331 no. 6013 pp. 76-79. DOI: 10.1126/science.1197349

Provided by Inside Science News Service

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kevinrtrs
1 / 5 (3) Mar 22, 2011
Sung hypothesized that over millions of evolutionary years, this molecule -- called COLDAIR --


So how did the plants survive or function whilst they were busy developing this ability to wake up and go to sleep at pre-determined times?

What will happen to a plant today if this clock mechanism is removed or switched off permanently?

Also, how did the plants survive without any pollinators whilst they were developing their clock work mechanism? Just when exactly in those billions of years did the plants suddenly become dependent on those pesky pollinators for their survival? How did those pollinators survive if they didn't have any food from the plants?
Ethelred
not rated yet Mar 24, 2011
So how did the plants survive or function whilst they were busy developing this ability to wake up and go to sleep at pre-determined times?
Why do you ask questions that you don't want the answer to? Unfortunately you will get one.

They were evolving in places that had less extreme weather. The insects evolved along with them.

What will happen to a plant today if this clock mechanism is removed or switched off permanently?
Depends on where the plant is and the species of plant as well.

Also, how did the plants survive without any pollinators
They had them. Insects have been around longer than flowering plants. There just weren't as many species.

Just when exactly in those billions of years
Millions Kevin. Get a clue.

did the plants suddenly become dependent on those pesky pollinators for their survival?
Never. It happened gradually not suddenly. Both you and Dr. Behe are completely and aggressively ignorant on that matter.

More
Ethelred
not rated yet Mar 24, 2011
How did those pollinators survive if they didn't have any food from the plants?
Its called co-evolution. Their ancestors made a less specialized living.

Now I must perform the Kevin banishing incantation.

When was the Flood Kevin? How come the Egyptians didn't notice drowning since the standard dates for the Flood have it occurring during at the time the Egyptians were building the pyramids?

Goodbye Kevin.

See he is really a Demon and not a human at all. He can be banished. And I don't even have to herd 2000 pigs over a cliff to do it.

Ethelred

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