April 9, 2008

OWU Professor Hopes Her Research Helps to ‘Cut the Mustard’

Associate Professor Laurie Anderson examines garlic mustard plants being grown in controlled conditions during her sabbatical at Duke University’s Phytotron.

The Ohio Wesleyan associate professor of botany/microbiology is spending the semester as a visiting scientist in the biology department at Duke University, where she is studying how global warming may affect the growth of one of Ohio’s most invasive plant species.

Anderson is utilizing Duke’s Phytotron to expand her research on garlic mustard (Alliaria petiolata), considered by the Ohio Department of Natural Resources to be one of the state’s top 10 most invasive plants. She also is studying how a native herb, Geum vernum, will respond to predicted future changes in temperature and atmospheric carbon dioxide.

“The context for this study is that we know warmer conditions and high CO₂ generally stimulate plant growth,” Anderson says. “Some people have used these observations to argue that global warming is a good thing that will stimulate crop growth. However, weeds and invasive species may also be stimulated by these conditions, and because these plants are already fast-growing and aggressive, their growth may be enhanced to a greater extent than crops or native plants.”

And while “garlic mustard” may sound harmless—and even tasty—there’s nothing appetizing about its continued spread through Ohio’s woodlands.

“Garlic mustard is known to reduce tree seedling growth by secreting toxins that kill beneficial fungi on the seedling roots,” Anderson says. “[It also] can suppress spring wildflowers through competition, and may reduce the diversity of native understory species. If it becomes an even more aggressive invader under future climate scenarios, it may become even more of a problem for native plants.”

Though she hasn’t collected her final data yet, Anderson already has observed that her test plants are growing faster in environments with warmer temperatures.

“These future temperatures could occur in about 60 to 90 years, if CO₂ emissions from the burning of coal, oil, and natural gas continue to increase,” Anderson says.

The Phytotron that Anderson is using for her research consists of 45 plant-growth chambers and six greenhouses that allow researchers to control light, temperature, carbon dioxide levels, and humidity.

“The benefit of the Phytotron is that scientists can examine the effects of different environmental variables in isolation,” Anderson explains. “For example, you can set up two growth chambers at high CO₂ and two at low CO₂, but keep all other variables that affect plant growth—light, temperature, humidity, and so on—the same. In this way, the effects of the increase in CO₂ can be studied while other factors are controlled.”

Following her semester at Duke, Anderson will return to Ohio Wesleyan, where she will continue to research garlic mustard.

“I have a current long-term study on the effects of garlic mustard on species diversity in the Ohio Wesleyan nature preserves,” Anderson says, “and if the results of the Phytotron study are interesting, I may continue to work with the Phytotron on garlic mustard responses to future climate.”

– Cole Hatcher