Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Tropical forest seed banks: a blast from the past

03.04.2009
Seeds of some tree species in the Panamanian tropical forest can survive for more than 30 years before germinating.

That is 10 times longer than most field botanists had believed.

Using the Lab's Center for Accelerator Mass Spectrometry to measure the amount of carbon 14 in seeds of the trees Croton billbergianus (Euphorbiaceae), Trema micrantha (Celtidaceae) and Zanthoxylum ekmannii ( Rutaceae), Lawrence Livermore National Laboratory scientist Tom Brown and University of Illinois at Urbana-Champaign colleague James Dalling found that seeds survived in the soil for 38, 31 and 18 years, respectively.

Previous demographic studies of pioneer tree species showed that seed persistence (the ability to survive in soil, awaiting favorable conditions for germination) is short, lasting only for a few years at most.

But in the tropical forests of Barro Colorado Island (BCI), Panama, Brown and Dalling found the seeds of some pioneer trees remain viable for many years.

“This is part of nature that wasn't really what people in the field thought was going on,” Brown said. “It turns out these seeds in soil just a few centimeters below the surface can survive a lot longer than anyone ever thought was possible.”

To increase the probability of encountering “old” seeds, Brown and Dalling used data from a forest plot to target sites in the forest occupied 20 years previously by species they suspected were capable of long-term persistence.

After Dalling germinated seeds extracting from surface soil layers at these sites, Brown carbon dated samples taken from the seed coat. However, unlike carbon dating techniques used by archeologists to estimate the age of objects from antiquity, he used a modern radiocarbon signal that is a consequence of atmospheric nuclear testing in the 1950s and early 1960s. The decline in radiocarbon concentration that has occurred since the test-ban treaty went into effect can be used as a signal to determine precisely when carbon became incorporated into plant tissue.

When disturbance kills canopy trees in tropical forest, light reaches the forest floor triggering the germination of seeds of pioneer tree species buried in the soil.

The age of these seeds, and thus the time that populations of pioneer species are able to survive between disturbance events, has long been open to question.

“This is a surprising result,” Dalling said. “Demographic models suggest that these species would not benefit from long persistence, and we doubted they would be able to survive anyway. Seeds dispersed onto the soil surface are prey to insect seed predators, and are exposed to an array of pathogens and decay organisms that proliferate in moist tropical soils.”

The results imply that buried seeds may be an important reservoir for genetic diversity in pioneer populations and may be as important as long distance dispersal in maintaining populations in fragmented habitats.

The research appears in the April edition of the journal, The American Naturalist.

Founded in 1952, Lawrence Livermore National Laboratory is a national security laboratory, with a mission to ensure national security and apply science and technology to the important issues of our time. Lawrence Livermore National Laboratory is managed by Lawrence Livermore National Security, LLC for the U.S. Department of Energy's National Nuclear Security Administration.

Anne Stark | EurekAlert!
Further information:
http://www.llnl.gov

More articles from Agricultural and Forestry Science:

nachricht Light green plants save nitrogen without sacrificing photosynthetic efficiency
21.11.2017 | Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign

nachricht Filling intercropping info gap
16.11.2017 | American Society of Agronomy

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

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

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

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,...

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

Previous evidence of water on mars now identified as grainflows

21.11.2017 | Physics and Astronomy

NASA's James Webb Space Telescope completes final cryogenic testing

21.11.2017 | Physics and Astronomy

New catalyst controls activation of a carbon-hydrogen bond

21.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>