Dissertation Research: Maintenance of a Leaf Shape Polymorphism in Ipomoea Hederacea

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9624051 Rausher Natural populations of the ivyleaf morning glory (Ipomoea hederacea) contain two distinct leaf shapes: some plants possess leaves with three lobes, while others possess unlobed leaves. Leaf shape differences of this magnitude have been shown to affect leaf temperature regulation (lobed leaves dissipate heat more effectively), and herbivore preference (some insects use leaf shape to recognize edible plants). However, an affect of leaf shape variation on plant performance in the field has never been demonstrated. Preliminary results from field observations of this plant species suggest that lobed and unlobed plants are specialized for different environmental conditions. The study will use large scale field experiments to quantify plant performance as a function of leaf shape in a natural setting. The study will also use greenhouse experiments to precisely control relevant environmental factors. This approach allows the determination of the effect of leaf shape on plant performance; may lead to an explanation of how this peculiar polymorphism is maintained; and may provide some insights into the importance of leaf shape for survival of plants in different environments.