Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Pollutant causes delayed flowering in plants

24.09.2004


Biologists have discovered that the air pollutant nitric oxide acts as a plant hormone to delay flowering in plants. The scientists discovered that while plants produce their own internal nitric oxide to regulate flowering, they are also influenced by external concentrations of the chemical.



The scientists said that although their findings are basic in nature, they suggest that the massive amounts of nitric oxide emitted as air pollutants from burning fossil fuels could affect the critical process of plant flowering. Since the decision to flower is so critical to reproduction, a delay in flowering could have important impacts on ecosystems, both plant and animal, they said.

The researchers, led by Duke University biologist Zhen-Ming Pei, published their findings in the Sept. 24, 2004, issue of the journal Science. Co-lead authors were Yikun He and Ru-Hang Tang from Duke. Other co-authors were Yi Hao, Robert Stevens, Charles Cook, Sun Ahn, Liufang Jing, Zhongguang Yang, Longen Chen, Fabio Fiorani and Robert Jackson, all of Duke; and Fangqing Guo and Nigel Crawford from the University of California at San Diego. The research was funded by the National Science Foundation and Duke University.


"The floral decision signaling pathway in plants has been studied for many, many years because the decision to flower is so critical to reproduction," Pei said. "And it was known that some of these pathways integrate external environmental signals, such as daily and seasonal changes in light, while others are autonomous pathways that act independently of external cues.

"However, nobody knew that nitric oxide was involved in these pathways. And nobody knew that plants would be affected by external concentrations of nitric oxide, as might be caused by air pollution." Such biochemical pathways are networks of protein enzymes that make up the signaling machinery that controls the flowering process.

"While our work is very much at a very detailed molecular level, I would bet that these findings have large-scale ecological implications regarding the effects of air pollution on flowering. It is entirely possible that global pollution by oxides of nitrogen could delay plant flowering worldwide," Pei said.

Pei and his colleagues began their studies by exposing the seedlings of the mustard plant, scientific name Arabidopsis, to a chemical that produced nitric oxide. The researchers found that such exposure enhanced the vegetative growth of the plants and significantly delayed flowering in a dose-dependent manner.

Arabidopsis is a widely used model plant in plant biology research, and its genetics and biology have been thoroughly studied. "This finding that externally applied nitric oxide delayed flowering was a big surprise," Pei said. "It had been known that internal nitric oxide regulated growth in plants. And, it was known that stimuli, such as drought, salt stress and pathogen infection, induced internal nitric oxide production. But it was not expected that external nitric oxide affected the flowering pathway."

To explore how the molecular machinery of the plant was affected by nitric oxide, the researchers identified mutant plants that produced high levels of nitric oxide and were hypersensitive to the chemical. They found that these plants were also late-flowering. Conversely, mutant plants that produced lower nitric oxide levels flowered early.

Genetic studies of such mutants revealed that nitric oxide appeared to affect genes that control both the environmentally sensitive pathways and the autonomous pathways that lead to flowering, Pei said. Thus, he said, nitric oxide may "integrate" both external and internal cues into the decision to flower.

Further studies, Pei said, will concentrate on understanding the nitric-oxide-controlled regulatory machinery in the flowering decision. Also, he said, the researchers will seek the receptor that nitric oxide plugs into in plant cells -- an activation process like a key fitting a lock. "This study will validate the concept that nitric oxide is an important plant hormone," Pei said. "It provides the hard evidence that is needed to demonstrate nitric oxide’s role, since flowering is such a fundamental, well-studied process."

Dennis Meredith | EurekAlert!
Further information:
http://www.duke.edu

More articles from Life Sciences:

nachricht The birth of a new protein
20.10.2017 | University of Arizona

nachricht Building New Moss Factories
20.10.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

Metallic nanoparticles will help to determine the percentage of volatile compounds

20.10.2017 | Materials Sciences

Shallow soils promote savannas in South America

20.10.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>