Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Over Time, An Invasive Plant Loses Its Toxic Edge

02.09.2009
Like most invasive plants introduced to the U.S. from Europe and other places, garlic mustard first found it easy to dominate the natives. A new study indicates that eventually, however, its primary weapon – a fungus-killing toxin injected into the soil – becomes less potent.

The study, in Proceedings of the National Academy of Sciences, is one of the first to show that evolutionary forces can alter the very attributes that give an invasive plant its advantage. In fact, the study suggests the plant’s defenses are undermined by its own success.

Garlic mustard comes from a family of smelly, sharp-tasting plants that includes cabbage, radish, horseradish and wasabi. Unlike most plants, which rely on soil fungi to supplement them with phosphorous, nitrogen and water, garlic mustard gets by without the extra help, said Richard Lankau, a postdoctoral researcher at the Illinois Natural History Survey (INHS) at the University of Illinois. Lankau led the study with INHS plant ecologist Greg Spyreas.

“For whatever reason, these plants just don’t hook up with the soil fungus,” Lankau said. Instead, garlic mustard produces glucosinolates, pungent compounds that leach into the soil and kill off many soil fungi, especially those native to North America. This weakens the native plants. As a result, garlic mustard now grows in dense patches in many North American woodlands, its preferred habitat. Those patches are often devoid of native plants.

Lankau began the new study with a seemingly obvious question: Once garlic mustard has vanquished most of its competitors, why would it invest as much in maintaining its toxic arsenal? He predicted – correctly, it turns out – that levels of glucosinolates in the plant would diminish over time.

“When you’re in a situation where the only thing you’re competing with is other garlic mustard, it may be that making lots of this chemical is not a very good idea,” he said.

Thanks to a study of historic herbarium records conducted by co-author Victoria Nuzzo, of Natural Area Consultants, N.Y., the researchers had access to a 140-year record of the age of garlic mustard populations across the eastern half of the U.S. The team collected garlic mustard seeds from 44 locations, grew them in a greenhouse and tested glucosinolate levels in each. Those tests found that older populations – those that have been present in an area for more than 30 years – produced lower levels of the fungicidal compounds than those that got their start less than two decades ago, Lankau said.

Genetic studies suggested that these patterns were the result of natural selection. That is, the plants that produced less of the toxin were more likely to survive and reproduce in older populations.

The researchers then grew the garlic mustard in soil from native woodlands. After a time, they removed these plants and potted native trees in the same soil. The trees did best in pots that had held plants from older populations of garlic mustard, indicating, again, that the plants’ toxin output had diminished over time, killing less of the fungus on which the native plants relied.

To determine if the decline in glucosinolate production was allowing native plants to return to areas previously dominated by garlic mustard in the wild, the researchers turned to a unique data set available in Illinois. The Critical Trends Assessment Program (CTAP) is a long-term initiative funded by the state Department of Natural Resources and administered by the INHS that monitors the status of plants, birds and insects across the state every five years. The CTAP began in 1997, and so data from the first two sampling periods were used (1997-2001 and 2002-2007)

Because CTAP includes data on plant abundance, including garlic mustard and native plants from across the state, the researchers were able to determine if native plants were declining or advancing in the presence of garlic mustard. Again, they found that older populations of garlic mustard – though still problematic – posed less of a threat to native plants than the newer ones did.

While this study focused on only one plant, the results indicate that some invasive plants evolve in ways that may make them more manageable over time, Spyreas said. This suggests that conservation efforts might be more effective if they focus on the most recently invaded areas, which – in the case of garlic mustard, at least – is probably where the most damage occurs.

This study was funded by the Agriculture and Food Research Initiative at the U.S. Department of Agriculture and by the Illinois Department of Natural Resources. The research team also included Adam Davis, of the Agricultural Research Service at the USDA.

Diana Yates | University of Illinois
Further information:
http://news.illinois.edu/news/09/0901garlicmustard.html
http://www.illinois.edu

More articles from Life Sciences:

nachricht A novel socio-ecological approach helps identifying suitable wolf habitats
17.02.2017 | Universität Zürich

nachricht New, ultra-flexible probes form reliable, scar-free integration with the brain
16.02.2017 | University of Texas at Austin

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Biocompatible 3-D tracking system has potential to improve robot-assisted surgery

17.02.2017 | Medical Engineering

Real-time MRI analysis powered by supercomputers

17.02.2017 | Medical Engineering

Antibiotic effective against drug-resistant bacteria in pediatric skin infections

17.02.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>