Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New research suggests delay in autumn colour is caused by increased atmospheric CO2 not global warming

15.11.2007
The delay in autumnal leaf coloration and leaf fall in trees is caused by rising levels of carbon dioxide (CO2) in the atmosphere and not by increased global temperatures, suggests a new study by researchers at the University of Southampton.

In recent years, woodland autumnal colour changes have been occurring later in the season whilst re-greening in spring has been occurring earlier. During the last 30 years across Europe, autumnal senescence – the process of plant aging where leaves discolour and then fall – has been delayed by 1.3 - 1.8 days a decade. To date, this has been explained by global warming, with increasing temperatures causing longer growing seasons.

However, while a strong correlation has been observed between increased global temperatures and earlier spring re-greening and bud break, the correlation between autumn leaf colour change and fall and temperature trends in 14 European countries is weak.

Over the 30 years that progressive delays in autumnal senescence have been observed, atmospheric CO2 has risen by 13.5 per cent. Experimental studies show that increased atmospheric CO2 affects plant physiology and function, influencing a myriad of processes.

The Southampton researchers undertook two large forest ecosystem experiments in which poplar (Populus) trees in separate plots were exposed to either ambient or elevated levels of CO2 from planting to maturity. The elevated concentration was at 550 parts per million, proposed as representative of concentrations that may occur in 2050. Changes in the tree canopy were measured by remote sensing.

The trees exposed to elevated CO2 retained their leaves for longer and also experienced a smaller decline in end of season chlorophyll content, resulting in a greener autumn canopy relative to that in ambient CO2.

Professor Gail Taylor, of the University’s School of Biological Sciences, explains:

‘The research data provide compelling evidence in terms of both the leaf and canopy that autumnal senescence in such forest ecosystems will be delayed as the atmospheric concentration of CO2 continues to rise, independent of increased temperatures.

‘Photosynthesis and canopy greenness are maintained for longer in elevated CO2. This is because a CO2 rich atmosphere allows the tree to generate carbon rich compounds that are known to prolong the life of leaves. These compounds may have a positive effect for carbon balance and stress tolerance but may also have a negative effect on the control of dormancy.

‘When trees keep their leaves for longer, they continue to photosynthesise but trees also need to set bud and if they don’t do that, it makes them susceptible to frost and other weather events. A key question now is whether we should be selecting trees which are better adapted to coping with increasing levels of CO2, perhaps considering different varieties and species to plant, rather than using locally sourced seed, as is current practice,’ she continues.

The study also provides the first insight into changes in the genetic make-up of Populus that can account for this shift to delayed senescence. Using cDNA microarrays, the researchers looked at approximately 20,000 genes and have identified a suite of genes that are switched on during delayed senescence in elevated CO2.

Sarah Watts | alfa
Further information:
http://www.soton.ac.uk

More articles from Ecology, The Environment and Conservation:

nachricht Successful calculation of human and natural influence on cloud formation
04.11.2016 | Goethe-Universität Frankfurt am Main

nachricht Invasive Insects Cost the World Billions Per Year
04.10.2016 | University of Adelaide

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

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

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Simple processing technique could cut cost of organic PV and wearable electronics

06.12.2016 | Materials Sciences

3-D printed kidney phantoms aid nuclear medicine dosing calibration

06.12.2016 | Medical Engineering

Robot on demand: Mobile machining of aircraft components with high precision

06.12.2016 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>