It has been accepted for 80 years that American elms (Ulmus americana) are tetraploids, trees with four copies of each chromosome. But there have also been persistent but dismissed rumors of trees that had fewer copies—triploids, which have three copies of chromosomes, or diploids, which have two copies.
Now botanist Alan T. Whittemore and geneticist Richard T. Olsen with USDA's Agricultural Research Service (ARS) have proven beyond question that diploid American elms exist as a subset of elms in the wild. Their findings will be published in the April edition of the American Journal of Botany. Whittemore and Olsen work at the U.S. National Arboretum operated by ARS in Washington, D.C.
American elms once lined the country's streets and dominated eastern forests until they succumbed by the millions after Dutch elm disease arrived in the United States in 1931. Yet elms are still one of the most important tree crops for the $4.7 billion-a-year nursery industry, especially since the introduction of a very few new trees with some tolerance to the disease. American elms remain popular because of their stately beauty, their rapid leaf litter decay and their ability to stand up to city air pollution.
It was one of the disease-tolerant elm trees—Jefferson, released jointly by ARS and the National Park Service in 2005—that put Whittemore and Olsen on the trail of the diploid.
"Jefferson is a triploid. To get a triploid elm, we thought there had to be a diploid parent out there somewhere in the wild that had crossed with a tetraploid," said Whittemore.
To settle the question, the two scientists tested elm trees from across the species' eastern and central U.S. range. About 21 percent of the wild elms sampled were diploid; some grew in stands with tetraploids, while others were larger groupings of diploids.
The small amount of genetic data now available suggests that at least some tetraploid and diploid elm populations have diverged significantly from one another, which strengthens the possibility of the diploid trees having genes for disease resistance that the tetraploids don't have, Whittemore said.
"We can't say yet whether this is a distinct race of U. americana or if we are really talking about a separate species," he said. "That's a job we will tackle this summer."
Kim Kaplan | EurekAlert!
Forest Management Yields Higher Productivity through Biodiversity
14.10.2016 | Technische Universität München
Farming with forests
23.09.2016 | University of Illinois College of Agricultural, Consumer and Environmental Sciences (ACES)
Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.
This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
27.10.2016 | Materials Sciences
27.10.2016 | Physics and Astronomy
27.10.2016 | Life Sciences