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 Waste in the water – New purification techniques for healthier aquatic ecosystems
24.07.2018 | Eberhard Karls Universität Tübingen

nachricht Plenty of habitat for bears in Europe
24.07.2018 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig

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: It’s All in the Mix: Jülich Researchers are Developing Fast-Charging Solid-State Batteries

There are currently great hopes for solid-state batteries. They contain no liquid parts that could leak or catch fire. For this reason, they do not require cooling and are considered to be much safer, more reliable, and longer lasting than traditional lithium-ion batteries. Jülich scientists have now introduced a new concept that allows currents up to ten times greater during charging and discharging than previously described in the literature. The improvement was achieved by a “clever” choice of materials with a focus on consistently good compatibility. All components were made from phosphate compounds, which are well matched both chemically and mechanically.

The low current is considered one of the biggest hurdles in the development of solid-state batteries. It is the reason why the batteries take a relatively long...

Im Focus: Color effects from transparent 3D-printed nanostructures

New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference

Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

 
Latest News

Quantum bugs, meet your new swatter

20.08.2018 | Information Technology

A novel synthetic antibody enables conditional “protein knockdown” in vertebrates

20.08.2018 | Life Sciences

Metamolds: Molding a mold

20.08.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>