Organisms are the objects of natural selection. Organismal function determines the success or failure of an individual: survival, growth, and reproductive output. My research examines how plant physiological function influences plant survival and performance. I am particularly interested in the diversity of form apparent throughout the plant bauplan and I try to understand the relationship between form and function in this broadest of senses.
I like to cross the boundaries of academic subfields to better understand the relationships between plants and their environment. I employ a variety of methods, including field studies, traditional ecophysiological measurements, stable isotopes, high resolution anatomical imaging, and, because most of my work is framed in an evolutionary context, phylogenetic comparative methods. I often modify existing equipment and design and develop new equipment to address my questions. Working across disciplines also means that I actively collaborate with people in other fields, including biogeochemistry, genomics, physics, conservation biology, and anthropology. I place organisms at the center of my focus and employ this diversity of fields to understand their structure, function, and evolution.
First, one main focus of my research has been the physiology and evolution of flowers–the most beautiful of plant structures. Nowadays there is no question that flowers play a critical role in reproduction, but this idea was heretical when it was proposed by Köhlreuter and Sprengel in the mid- to late 1700s. Since then, our understanding of the diversity and complexity of flowers has been based primarily on the role of pollinators in shaping floral form. Yet, floral structures experience the same physiological constraints as other plant structures, though we know little about the physiological processes involved in producing and maintaining them. The incredible (and, often, bizarre) morphologies of many flowers may be enabled by novel physiological strategies and constrained by the fundamental necessity of resource supply. Physiological traits may both promote and inhibit selection by pollinators. My research elucidates the mechanisms of water transport to flowers and examines the macroevolutionary patterns of floral physiological variation.
Second, variation in genome size has long been considered an enigma, not only in plants but across all domains of life. While genome size is thought to scale with organismal complexity, this relationship is not always obvious or easy to quantify. Furthermore, the size of the genome limits variation in cell size, which determines rates of metabolism. With collaborators in evolutionary genomics and ecophysiology, I am determining (1) the extent to which genome size variation influences organismal structure and function, (2) how shifts in metabolism influence selection on genome size, and (3) how variation in genome size is linked to genome structure. Working at the interface of subfields of biology, this work promises to develop a more unified framework for how we understand the informational, structural, and functional dimensions of life.