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 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 >>>