8/21/14 ASHLAND, Ohio – Dr. Jeff Weidenhamer, trustees’ distinguished professor of chemistry at Ashland University, has just returned from spending five months in Australia as part of an international research partnership through the Graham Centre for Agricultural Innovation at Charles Sturt University.
Weidenhamer’s visit was funded by an Endeavour Research Fellowship through the Australian government. He was hosted by Professor Leslie Weston at Charles Sturt University.
Weidenhamer said the research partnership ties to his educational background and his deep interest in the chemical aspects of plant-plant interactions. In addition, it afforded him the opportunity to learn more about the newly developing field of metabolomics in Weston’s laboratory.
“During my master’s work I worked with Glover Triplett at Ohio State University, who had done some of the pioneering research on no-tillage agriculture,” he said. “I developed an interest in the question of whether the use of chemicals for weed control in this system could be reduced by using crops or cover crops to provide natural weed control.”
Weidenhamer’s Ph.D. and postdoctoral research focused on understanding how allelopathy works in a natural community (the Florida Scrub) to prevent invasion. “Through that work I recognized the need for new methods to study allelopathy, which has been one of my major research objectives over the past 25 years,” he said.
Weidenhamer has contributed both new bioassay methods based on density-dependent phytotoxicity effects and most recently new soil analysis methods based on silicone materials to measure the dynamics of allelochemicals in the rhizosphere. His research in chemical ecology has been funded by the U.S. National Science Foundation.
Weidenhamer previously visited Charles Sturt University for six weeks in 2011 as a Fulbright Senior Science Specialist in Agriculture.
While at the Graham Centre, Weidenhamer participated in studies to evaluate the root exudates of weed-suppressive wheat varieties, in particular, in order to determine whether these varieties suppress weeds through chemicals in their root exudates.
A long term goal of these studies, which are ongoing, is to learn how root exudation changes in response to climate change. “These studies were done in collaboration with Dr. Weston and researchers at CSIRO Plant Industries to understand the factors involved in improved wheat performance in Australia, in light of a changing climate,” he said.
Weidenhamer said that plant roots may exude up to 20 percent or more of the carbon fixed in photosynthesis into the surrounding soil. The exudation of these compounds can defend plants against pathogens, encourage the growth of beneficial microorganisms and serve a number of other purposes.
“Recent findings suggest that more carbon actually exits the roots through exudation in response to climate change, which impacts activity of soil microbes, and also impacts the rate of carbon turnover in soil,” he said. “Root exudates can be biologically active against competitors as well, so a better understanding of root exudation is crucial to understanding how crops such as wheat may respond to climate change.”
Weidenhamer also assisted Weston in studies of the invasive weed Paterson’s Curse, which has spread widely across Australia after arriving there from Europe. Techniques developed by Weidenhamer and Ashland University colleague Brian Mohney are being used to measure the release of compounds from the roots of this plant.
Weidenhamer concluded his time abroad by presenting two papers, based on his research, at the Seventh World Congress on Allelopathy in Vigo, Spain. At the Congress, he was honored by being selected as a winner of the Molisch Award, given by the International Allelopathy Society to recognize continuing contributions to research excellence in allelopathy, which is the study of the chemical inhibition of plant growth by chemicals released by other plants. This award is given to a researcher who has made major and lasting contributions to the science of allelopathy in the course of his or her career.
Ashland University, which has been ranked in the top 200 colleges and universities in U.S. News and World Report’s National Universities category, is a mid-sized, private university conveniently located a short distance from Akron, Cleveland and Columbus, Ohio. Ashland University (www.ashland.edu) values the individual student and offers a unique educational experience that combines the challenge of strong, applied academic programs with a faculty and staff who build nurturing relationships with their students. ###