About Jeffrey D. Weidenhamer

Chemical Ecology is the study of the role of chemical substances in mediating relationships between organisms. My particular interest is in the phenomenon of allelopathy, or chemical interference among higher plants.
It has long been suspected that toxic chemicals released by plants into the soil may function as natural herbicides to inhibit the growth of neighboring plants. If this is the case, such chemicals could influence important ecological processes such as successional changes in plant communities over time, and nutrient cycles. Recently, it has been proposed that the success of certain invasive plants might be due to the chemical toxins they produce. One of the major barriers to evaluating these ideas has been the difficulty of analyzing the release of these chemicals in the soil. My recent work focuses on the development and application of new polymer-based materials such as polydimethylsiloxanes that can trap these chemicals as they are released in the soil, allowing these toxins to be isolated and measured. This research will provide an inexpensive tool for other scientists to use in investigating these problems. This work is funded by the National Science Foundation, Division of Ecological Biology.
The broader implications of this project are two-fold. First, understanding how chemicals released by plants do or do not function as natural herbicides may suggest new ways to manage and control certain invasive species that have caused widespread damage to natural and managed land. In agriculture, such chemicals might be used as more ecologically-sound replacements for synthetic herbicides.
In addition to my currently funded work on rhizosphere analysis, a significant portion of my previous research has been in the area of greenhouse and field methods for studies of chemical interference between plants. It has proven extraordinarily difficult to demonstrate that the inhibition of plant growth observed in the field or greenhouse are due to toxic chemicals being released by a neighbor, and not due to effects such as competition for moisture and nutrients. We have found that phytotoxic effects are density-dependent at low plant densities, there is more of the toxin available per plant and therefore a greater toxic effect than is observed at higher densities. This sort of response is inconsistent with resource competition.

Positions

Present Professor of Chemistry, Ashland University
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Curriculum Vitae


Disciplines

None


Allelopathy -- Research Methods (13)

Allelopathic Effects of Florida Scrub Perennials (3)

Lead Contamination (9)