DISSERTATION RESEARCH: Test of Competing Plant Defense Hypotheses in a New Model System

Tulane University, New Orleans LA

Investigators

Abstract

Using a combination of field work in the rain forest of Costa Rica, greenhouse experiments, and laboratory analysis, the investigators will examine the relationships between soil fertility and the ability of plants to defend themselves against the wide variety of insect herbivores that feed on their leaves. Plants produce a broad array of toxic chemicals in their leaves that are not directly related to plant growth or maintenance. These toxins may function as defenses against herbivores or other organisms that attack plants. The amounts of toxic chemicals in plants may vary in response to environmental factors such as soil nutrients or light availability, or in reponse to herbivore attack, although the internal changes in plants that occur when defensive chemical amounts change are poorly understood. The investigators will manipulate the amounts of defensive chemicals in plants by varying the availability of soil nutrients and then measure overall changes in chemical concentration within the plant. Broader Impacts: The proposed research will address a long-standing debate about the importance of resources in plant defense against herbivores. Understanding the relationship between environmental variables, plant defense, and herbivores may contribute to conservation, agricultural research, and pest control. Our research will contribute to the training of high school, undergraduate and graduate students in ecological and chemical research techniques. The broader community will be affected through involvement of volunteers in research. This work will contribute to outreach programs in local public schools in New Orleans and seminars in Costa Rica, and results will be distributed through popular and scientific publications.