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 Carefully crafted light pulses control neuron activity
20.11.2017 | University of Illinois at Urbana-Champaign

nachricht Could this protein protect people against coronary artery disease?
17.11.2017 | University of North Carolina Health Care

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Heavy nitrogen molecules reveal planetary-scale tug-of-war

20.11.2017 | Earth Sciences

Taking a spin on plasma space tornadoes with NASA observations

20.11.2017 | Physics and Astronomy

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>