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!
Raiding the rape field
23.05.2018 | Julius-Maximilians-Universität Würzburg
New technique reveals details of forest fire recovery
17.05.2018 | DOE/Brookhaven National Laboratory
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.
The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
23.05.2018 | Life Sciences
23.05.2018 | Life Sciences
23.05.2018 | Physics and Astronomy