Low-Temperature Biology/Crop Physiology
611 Bradfield Hall
(607) 255-1707
e-mail: pls4@cornell.edu
B.S. 1963 Colorado State University
M.S. 1964 University of Arizona
Ph.D. 1966 Purdue University
Peter L. Steponkus, The Liberty Hyde Bailey Professor of Crop Physiology, joined the Cornell Faculty in 1968 as an Assistant Professor in the Department of Floriculture and Ornamental Horticulture. He joined the Department of Agronomy in 1977. Prior to his Cornell appointment, he was an assistant professor in the Department of Horticulture at the University of Arizona (1966-1968). Professor Steponkus' primary research interests are in the area of low-temperature biology and currently he is the President-Elect of the Society for Cryobiology, the Editor-in-Chief of Advances in Low-Temperature Biology, Associate Editor of Cryo-Letters, and a member of the Editorial Board of Cryobiology.
Research Program
My research program is devoted to various facets of low-temperature biology. The primary area of interest is in cellular and molecular aspects of freezing injury and cold acclimation of plants. The emphasis of these studies is on freeze-induced membrane destabilization and the role of membrane lipid alterations during cold acclimation, with emphasis on the stability of the plasma membrane. Studies in this area include characterization of the stress-strain relationship and mechanical properties of the plasma membrane in relation to osmotic excursions that occur during a freeze/thaw cycle; hydration forces and lyotropic phase behavior of plasma membrane lipids in relation to extreme dehydration that occurs during freezing; and the influence of freeze-induced dehydration on membrane ultrastructure as determined by electron microscopy investigations. As part of this research, we have developed computer-enhanced cryomicroscopy facilities for studies of cells and tissues at cryogenic temperatures.
A second major research interest is to develop new techniques for cryopreservation of plant, animal and insect germplasm. This research is based on the study of liquid-to-glass transformations (vitrification) in biological systems at cryogenic temperatures and biophysical studies of ice nucleation and ice crystal growth in concentrated solutions of cryoprotectants. These studies have resulted in the development of vitrification procedures for isolated protoplasts, suspension cultures and shoot-tips of several different plant species and Drosophila melanogaster embryos.
Courses Taught
SCAS 610 Physiology of Environmental Stresses
Selected Publications
Steponkus, P.L., R. Langis and S. Fujikawa. 1992. Cryopreservation of plant tissues by vitrification. In: Advances in Low-Temperature Biology, Volume 1, edited by P.L. Steponkus. pp. 1-61. JAI Press, Ltd. London.
Steponkus, P.L., M. Uemura and M.S. Webb. 1993. Redesigning crops for increased tolerance to freezing stress. In: Interacting Stresses on Plants in a Changing Climate, edited by M.B. Jackson and C.R. Black. pp. 697-714. Springer-Verlag, Berlin.
Steponkus, P.L., M. Uemura and M.S. Webb. 1993. A contrast of the cryostability of the plasma membrane of winter rye and spring oat--two species that widely differ in their freezing tolerance and plasma membrane lipid composition. In: Advances in Low-Temperature Biology, Volume 2, edited by P.L. Steponkus. pp. 211-312. JAI Press, Ltd. London.
Steponkus, P.L. and S. Caldwell. 1993. An optimized procedure for the cryopreservation of Drosophila melanogaster embryos. Cryo-Letters 14:377-382.
Steponkus, P.L., M. Uemura and M.S. Webb. 1995. Freeze-induced destabilization of cellular membranes and lipid bilayers. In: Permeability and Stability of Lipid Bilayers, edited by E.A. Disalvo and S.A. Simon. pp. 233-260. CRC Press, Boca Raton, FL.