Professor Jeff Amthor


The physical and chemical transformation of solar energy, carbon dioxide, nitrogen, and other elements into new plant matter determines both the quantity and quality of crop production and the overall functioning of earth’s biosphere. I am intrigued by how–and how efficiently–plants carry out that transformation, and I believe that an understanding of the biophysical and biochemical limits to plant productivity is an understanding of the limits of human welfare, and life itself.

Research Interests

The ways that higher plants coordinate and integrate myriad physical, chemical, and biological processes to produce new biomass, and maintain existing biomass, fascinates me. I am particularly interested in the theoretical limits to plant productivity, both within crops and unmanaged ecosystems. The role of higher-plant metabolism in regulating the global carbon cycle–on the time scale of months to decades–is also a topic of interest to me. Finally, I wish to understand how variation in temperature, moisture, and atmospheric carbon dioxide concentration constrain plant growth and maintenance metabolism, and therefore influence ecosystem structure and functioning.

To pursue these interests my research focuses on mechanistic modeling of plant physiology and environmental physics. The models are framed within the context of biological and ecological hierarchies (i.e., the relationships between and within different levels of biological organization). Process representations are based on physical and biochemical understanding, when possible, as a means to explain the linkages between environmental constraints and whole-plant/ecosystem functioning and success. A second approach I use to address my research interests involves the synthesis (and attempts to mechanistically explain) results of experimental studies of plant-environment interactions. This includes collaborating with interdisciplinary research teams addressing high-priority science questions about effects of environmental change on plant ecophysiology.

I expect to build novel bridges between experimental research, in both the field and laboratory, and process modeling to create and communicate improved understanding of environmental and genetic constraints on the health and productivity of managed and unmanaged ecosystems of special importance to New South Wales and Australia, including the potential for biofuel production. As a new member of the University of Sydney faculty I look forward to exciting interactions with undergraduate and graduate students, fruitful collaborations with postdoctoral research associates, and new and continuing efforts to advance the frontiers of plant science with colleagues throughout the world.


Jeff Amthor earned BS and MS degrees in agronomy at Texas A&M University (his advisor was J.B. Beard), and then MS and PhD (1987) degrees in forestry and environmental studies (focusing on plant ecophysiology) at Yale University under the supervision of F.H. Bormann. He was a visiting scientist at the Boyce Thompson Institute for Plant Research while conducting his dissertation research on the effects of ozone on plant physiology. While a graduate student at Yale, Jeff was employed by the Yale Computer Center as a computer programming consultant to students, faculty, and staff.

After completing his PhD, Dr. Amthor was Lecturer in Forest Ecophysiology atYale and coordinator of Yale’s research in the Hubbard Brook Ecosystem Study. He participated in the first large-scale free-air CO2 enrichment (FACE) experiments (as a process-based modeler) while employed as a plant physiologist by the U.S. Department of Agriculture (Agricultural Research Service) in Phoenix, Arizona, and later worked with R.S. Loomis at the University of California-Davis. Jeff was Environmental Scientist and Group Leader in Biogeochemical Cycles at the U.S. Department of Energy’s (DOE’s) Lawrence Livermore National Laboratory (California), where he conducted and managed research on the global carbon cycle and earth system (climate) modeling, and then senior R&D staff member at DOE’s Oak Ridge National Laboratory (Tennessee), where he studied effects of climatic change on the structure and functioning of forest ecosystems. For the 10 years before joining the University of Sydney faculty (in 2010), Prof. Amthor was a research-program manager at DOE headquarters (outside Washington, DC), designing and implementing basic-research programs aimed at understanding effects of climatic change on a wide range of terrestrial ecosystems including temperate and boreal forests, grasslands, shrublands and woodlands, crops, deserts, and tundra. He was also Affiliate Professor at Auburn University.

Professor Amthor has published widely cited journal articles, book chapters, and a book about plant respiration, plant-environment interactions, crop productivity, and the terrestrial carbon cycle. His five most popular sole-authored publications are each cited in more than 180 scientific-journal articles.

Recent publications

  • Amthor JS (2010) From sunlight to phytomass: on the potential efficiency of converting solar radiation to phyto-energy. New Phytologist 188: 939-959
  • Amthor JS, Hanson PJ, Norby RJ, Wullschleger SD (2010) A comment on "Appropriate experimental ecosystem warming methods by ecosystem, objective, and practicality" by Aronson and McNulty. Agricultural and Forest Meteorology 150: 497-498
  • Amthor JS (2007) Improving photosynthesis and yield potential. In: P. Ranall(ed) Improvements of Crop Plants for Industrial End Uses. Springer, Dordrecht, The Netherlands, 27-58
  • Tubiello FN, Amthor JS, Boote KJ, Donatelli M, Easterling W, Fischer G, Gifford RM, Howden M, Reilly J, Rosenzweig C (2007) Crop response to elevated CO2 and world food supply. A comment on "Food for Thought..." by Long et al., Science 312:1918-1921, 2006. European Journal of Agronomy 26: 215-223
  • Pritchard SG, Amthor JS (2005) Crops and Environmental Change. Haworth Press, New York, 442 p.
  • Amthor JS (2003) Efficiency of lignin biosynthesis: a quantitative analysis. Annals of Botany 91: 673-695
  • Amthor JS (2001) Effects of atmospheric CO2 concentration on wheat yield: review of results from experiments using various approaches to control CO2 concentration. Field Crops Research 73: 1-34
  • Amthor JS, Baldocchi DD (2001) Terrestrial higher plant respiration and net primary production. In: J Roy, B Saugier, HA Mooney (eds) Terrestrial Global Productivity. Academic Press, San Diego, 33-59
  • Amthor JS (2000) The McCree–de Wit–Penning de Vries–Thornley respiration paradigms: 30 years later. Annals of Botany 86: 1-20
  • Loomis RS, Amthor JS (1999) Yield potential, plant assimilatory capacity, and metabolic efficiencies. Crop Science 39: 1584-1596