Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Genetic snooze button governs timing of spring flowers

11.08.2006
In the long, dark days of winter, gardeners are known to count the days until spring. Now, scientists have learned, some plants do exactly the same thing.

Addressing scientists here today (Aug. 9) at a meeting of the American Society of Plant Biologists, University of Wisconsin-Madison researcher Richard Amasino described studies that have begun to peel back some of the mystery of how plants pace the seasons to bloom at the optimal time of year.

"Flowering at the right time is all about competition," says Amasino, Howard Hughes Medical Institute Professor and UW-Madison professor of biochemistry.

Amasino and his colleagues have studied, in particular, the behaviors of biennial plants, which require long periods of exposure to the cold to initiate flowering in the spring. What they have found reveals some of the complex interplay of genes and environment and provides hints that, one day, it may be possible to exert precise control over flowering, a process essential for plant reproduction and fruiting and that has enormous implications for agriculture.

Flowers are the reproductive organs of plants and are responsible for forming seeds and fruit. As their name implies, biennials complete their life cycles in two years, germinating, growing and overwintering the first year. The second year, the plants flower in the spring and die back in the fall.

That biennial strategy, Amasino explains, arose as flowering plants, which first evolved some 100 million years ago during the age of the dinosaurs, spread to fill the niches of nature. Spring blooming confers numerous advantages, not the least of which is leafing out and flowering before the competition.

But how do the plants know when to flower?

"If you carve out that niche, you need to get established in the fall, but you need to make darn sure you don't flower in the fall," Amasino says. In the case of biennials, "the plants can somehow measure how much cold they've been exposed to, and then they can flower rapidly in the spring niche."

Exposure to the cold triggers a process in plants known as vernalization, where the meristem - a region on the growing point of a plant where rapidly dividing cells differentiate into shoots, roots and flowers - is rendered competent to flower.

In a series of studies of Arabidopsis, a small mustard plant commonly used to study plant genetics, Amasino and his colleagues have found there are certain critical genes that repress flowering.

"The plants we've studied, primarily Arabidopsis, don't flower in the fall season because they possess a gene that blocks flowering," Amasino explains. "The meristem is where the repressor (gene) is expressed and is where it is shut off."

The key to initiating flowering, according to the Wisconsin group's studies, is the ability of plants to switch those flower-blocking genes off, so that they can bloom and complete their pre-ordained life cycles.

But how that gene was turned off was a mystery until Amasino and his group found that exposure to prolonged cold triggered a molecular process that effectively silenced the genes that repress flowering.

Another processes known as bud dormancy, which is similar to vernalization, occurs in many plants that grow in temperate climates. "Bud dormancy is not broken until the plant has 'counted' a sufficient number of days of cold to ensure that any subsequent warm weather actually indicates that spring has arrived," Amasino says.

The Wisconsin team led by Amasino has worked out much of the process of vernalization, and their hope is to add to knowledge of other cold-regulated processes such as the regulation of bud dormancy in trees. Bud dormancy may be similar to vernalization or, the Wisconsin scientists adds, it may be controlled by a completely different mechanism.

"But our study of vernalization may help us get our foot in the door," Amasino says. "It gives us a basis to test whether there are similarities."

Knowing the genes that control flowering and how they work provides a much more detailed working knowledge of plants, many that are useful to humans and some of great economic importance, Amasino explains.

"This is important agriculturally," he notes. "There are many crops - cabbage, beets - that we don't want to flower. Many of the cultivated varieties we use are never exposed to cold in a typical farmer's field growing season."

When that is the case, a cold snap can fool sugar beets, for example, into flowering, a process that can ruin the crop by redirecting nutrients from the valuable root to the production of seeds and flowers.

And although Amasino and his group have demystified some of the molecular underpinning of the familiar process of flowering, the biochemist emphasizes that much of the fine biochemical detail remains to be worked out.

Richard Amasino | EurekAlert!
Further information:
http://www.wisc.edu

More articles from Life Sciences:

nachricht Zap! Graphene is bad news for bacteria
23.05.2017 | Rice University

nachricht Discovery of an alga's 'dictionary of genes' could lead to advances in biofuels, medicine
23.05.2017 | University of California - Los Angeles

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

Im Focus: Bacteria harness the lotus effect to protect themselves

Biofilms: Researchers find the causes of water-repelling properties

Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

Innovation 4.0: Shaping a humane fourth industrial revolution

17.05.2017 | Event News

 
Latest News

Scientists propose synestia, a new type of planetary object

23.05.2017 | Physics and Astronomy

Zap! Graphene is bad news for bacteria

23.05.2017 | Life Sciences

Medical gamma-ray camera is now palm-sized

23.05.2017 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>