Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Dartmouth researchers find two circadian clocks in the same plant tissue

08.05.2003


Dartmouth researchers have found evidence of two circadian clocks working within the same tissue of the plant Arabidopsis thaliana, a flowering plant often used in genetic studies. Their results suggest that plants can integrate information from at least two environmental signals, light and temperature, which is important in order to respond to seasonal changes.



The study, published this week, appears in the online edition of the Proceedings of the National Academy of Sciences.

"Having two clocks with different sensitivities to light and to temperature is a better way to ensure that both signals of environmental input are fully understood by the plant," says C. Robertson McClung, professor of biological sciences and an author on the paper. "The plant can then process the data and make decisions about flowering, which is a very critical decision. Arabidopsis flowers in response to the lengthening days of spring, but if it were to flower too soon and there is a nasty frost, the blossoms will die. Early spring is cool, so it makes sense for a plant to clue in to more than one environmental signal."


The researchers, which included McClung, Todd Michael, a former graduate student who is now a postdoctoral fellow at the Salk Institute in San Diego, and Patrice Salomé, a graduate student, followed rhythms in two kinds of genes – one kind that encodes for photosynthesis and another not involved in photosynthesis. The genes in this study are both found in the mesophyll, the spongy inner layer of tissue in leaves.

To measure gene expression, McClung and his students manipulated the clock-controlled genes they were studying and put them in control of luciferase, the enzyme that makes fireflies glow, and then introduced that new gene into Arabidopsis. Each plant in the study had only one altered, light-making gene. When that gene was stimulated, light production was captured by a very sensitive camera. McClung and his team used this method to test how Arabidopsis responded to conflicting signals, such as a cycle of cool days and warm nights.

"We found if we gave them warm nights and cool days, the photosynthetic gene ignored the temperature signal and behaved as if it was only seeing the light signal, which makes sense because photosynthesis absolutely depends on daylight," says McClung. "But the other gene ignored the light signal and responded to the temperature signal. That kind of surprised us."

McClung and his students continued the study by examining how the circadian clocks were reset by different stimuli. For example, people respond to a pulse of light prior to dawn by readjusting their internal clocks a few hours ahead. The same pulse of light administered after dusk delays the clock. The researchers found that the non-photosynthetic gene, which favored temperature signals, showed an exaggerated response to pulses of cold air relative to the photosynthetic gene that responded more to light signals.

"This could only occur if the two genes were responding to two different clocks," says McClung. "Since both the genes are expressed in the mesophyll, it’s clear that both clocks are operating in that tissue. This is exciting because this is the first good example of two clocks operating within a single tissue in any multicellular organism. We’re not quite at the point where we can find out if there are two clocks operating in a single cell, but that’s our goal."


This research is supported by the National Science Foundation.

Sue Knapp | EurekAlert!
Further information:
http://www.dartmouth.edu/

More articles from Life Sciences:

nachricht Microscope measures muscle weakness
16.11.2018 | Friedrich-Alexander-Universität Erlangen-Nürnberg

nachricht Good preparation is half the digestion
16.11.2018 | Max-Planck-Institut für Stoffwechselforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

Purdue cancer identity technology makes it easier to find a tumor's 'address'

16.11.2018 | Health and Medicine

Good preparation is half the digestion

16.11.2018 | Life Sciences

Microscope measures muscle weakness

16.11.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>