DATE: Tuesday, January 23, 2018
TIME: 02:00 PM - 03:00 PM
LOCATION:Building 2 - Level 5 - Room 5220
Abstract:Plant cell walls are complex, fiber-reinforced biocomposites that change during the growth process. One very importance aspect for growth is the time-dependent (viscoelastic) nature of the cell wall that allows the wall to relax and expand. In this presentation, the role of viscoelasticity and its impact on measurement interpretation and modeling are discussed. In particular, the computational modeling of cell wall behavior must include an appropriate time-dependent component in order for force-displacement responses to have physical relevance. In addition, model inputs are often derived from scanning probe microscope experiments (e.g., nanoindenter, atomic force microscope) that are now being applied to plants. However, data analysis is often made under the assumption of a quasi-static material response for which the loading rate is presumed unimportant. Here, the impact of such assumptions is discussed and quantified using several examples. Prospects for modeling of plant cell clusters will also be examined.Bio:Joseph A. Turner is currently the Robert W. Brightfelt Professor of Mechanical and Materials Engineering at the University of Nebraska-Lincoln (UNL). He received his B.S. (Eng. Sci.) and M.Engr. (Eng. Sci. Mech.) degrees from Iowa State University in 1988 and his Ph.D. (Theoretical and Appl. Mech.) from the University of Illinois at Urbana-Champaign (UIUC) in 1994. After a postdoctoral experience at UIUC, he served as an Alexander von Humboldt Postdoctoral Fellow at the Fraunhofer Institute for Nondestructive Testing (IZFP) in Saarbrücken, Germany before joining UNL in 1997. He is a Fellow of the Acoustical Society of America and recipient of the Wilhelm Bessel Forschungspreis from the Alexander von Humboldt Foundation (2014). His research interests are associated with characterization of a variety of materials and their microstructures using ultrasound/acoustics, nanoindentation, and atomic force microscopy with analytical, numerical and experimental components.
DATE: Wednesday, January 31, 2018
LOCATION:Building 4 - Level 5 - Room 5220
Abstract:Modern agriculture depends increasingly on large-scale, genetically uniform cropping systems requiring intensive use of chemicals to control pathogens. The wild ancestors of our domesticated crops, however, contain genetically diverse resistance (R) genes. Deploying these genes in crops represents an underexploited and environmentally benign disease control option. Cross breeding R genes from wild relatives into crops takes many years, is hampered by the co-introduction of linked and undesirable traits, and single R genes often break down when deployed over a large area. The pyramiding of multiple, cloned R genes would prevent linkage drag and provide a more durable control option by delaying the evolution of resistance-breaking strains of the pathogen. In my presentation, I will describe a series of enabling technologies and how we are using these to accelerate the discovery and cloning of disease resistance genes from laboratory-generated and natural populations of wheat and wild wheat, and our plans for deploying cloned R genes in elite wheat varieties.Bio:Brande’s research programme explores the genetics of disease resistance in wheat. This research has led to developing fast, new and efficient methods for gene discovery and cloning which use mutant and natural populations followed by sequence alignment to locate genes, a technique which could be applied to a range of crop plants. Brande has also developed a method for halving the generation time of wheat and other crops, in a controlled environment, dramatically speeding up capabilities for research and breeding purposes.