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

通过结合哥斯达黎加热带雨林的野外工作、温室实验和实验室分析，研究人员将研究土壤肥力与植物抵御以其叶片为食的各种食草昆虫的能力之间的关系。 植物在叶子中产生大量有毒化学物质，这些化学物质与植物的生长或维持没有直接关系。 这些毒素可以作为防御食草动物或其他生物攻击植物。 植物中有毒化学物质的含量可能会因环境因素如土壤养分或光照的可用性而变化，或者对草食动物的攻击作出反应，尽管对防御性化学物质含量变化时植物内部发生的变化知之甚少。 研究人员将通过改变土壤养分的可利用性来操纵植物中防御性化学物质的数量，然后测量植物中化学物质浓度的总体变化。更广泛的影响：拟议的研究将解决长期存在的关于资源在植物防御食草动物中的重要性的争论。了解环境变量，植物防御和食草动物之间的关系可能有助于保护，农业研究和害虫控制。 我们的研究将有助于培养高中生、本科生和研究生的生态和化学研究技术。 更广泛的社区将通过志愿者参与研究而受到影响。 这项工作将有助于新奥尔良当地公立学校的推广计划和哥斯达黎加的研讨会，成果将通过大众和科学出版物传播。

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 whendefensive 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 pestcontrol. Our research will contribute to the training of high school, undergraduate and graduate students in ecological and chemical researchtechniques. The broader community will be affected through involvement ofvolunteers in research. This work will contribute to outreach programs inlocal public schools in New Orleans and seminars in Costa Rica, and resultswill be distributed through popular and scientific publications.