Interdisciplinary PhD in Molecular Biosciences

Dr. Jeffrey L. Walck - Research Interests

The Walck laboratory focuses primarily on the ecology, evolution, and biogeography of seed dormancy and germination and on conservation seed science.

Dormancy is a form of developmental arrest promoting survival of many organisms. It is controlled by several genes and is strongly influenced by genetic and environmental factors. Germination of seeds is a fundamental stage in a plant's life cycle, and mechanisms that regulate germination through dormancy are an important aspect of a species' life history and ecology. Environmental conditions have selected for germination to occur when plant growth, development, and reproduction are optimal. Thus, the timing of dormancy release and of germination is an important factor influencing the ecological and geographical distributions of plants.

Utilizing a multidisciplinary approach, I tackle aspects of plant regeneration over broad spatial and temporal scales. I try to understand the ecological, evolutionary, and biogeographical processes that shape the functional diversity of plants, with particular emphasis on seed ecophysiology. To this end, the roles that abiotic factors play in the ecology of physiological traits in relation to climate and life history are studied. Coupling with molecular phylogenetic studies, evolutionary and biogeographic patterns of traits are examined particularly for Asian-American plant disjunctions. These Tertiary relicts also are the focus of understanding the relationships among physiological, genetic, and morphological traits and in particular ecophysiological stasis/divergence.

Early developmental stages of plants are expected to be more sensitive to environmental constraints than adult stages, and as such, represent a major bottleneck to recruitment in a climate-changed world. I try to discover how plant traits at the population level impact larger-scale processes at the community/ecosystem level. Since temperature and precipitation are critical drivers of seed dormancy and germination, changes in environmental cues related to climate change will undoubtedly affect plant regeneration. Thus, population and community level impacts of climate change acting through the seed germination stage are studied.