UC Davis Plant SciencesProf. Don J. Durzan



B.Sc. in Biology and Chemistry (honors, 1959) was granted from McMaster University, Hamilton, Ontario, Canada.  That year Don was one of the founding members of the Canadian Society of Plant Physiologists. He also joined the Canadian Public Service as a Research Officer in the Department of Northern Affairs and National Resources to initiate studies with radioactive isotopes for studying the flowering in forest trees at Chalk River, Ontario.  In 1960 Don entered directly for PhD studies in Plant Physiology and Biochemistry at Cornell University where he served as a Research Associate in Physiology to Professor F.C. Steward, FRS. At that time, Steward’s laboratory demonstrated cellular totipotency in plants and introduced chromatographic and autoradiographic methods for the identification of new plant amino acids and their roles in plant nitrogen metabolism. After completing his Ph D in 1963, Don returned to Chalk River as Head of the Tree Physiology and Biochemistry at the Petawawa Forest Experiment Station. Don returned to Cornell as Visiting Professor in Steward’s new Laboratory for Cell Physiology Growth and Development (1967-1968). He also developed an automated analytical method for the determination of guanidino compounds in physiological fluids using an amino acid analyzer.  

In 1972 Don became Head of Biochemistry in Forest Ecology for the Canadian Forest Service in Ottawa. He trained four National Research Council Postdoctoral Fellows and presented courses in plant physiology and nitrogen metabolism at Carleton and Queen's Universities. New methods were developed for cloning conifers and for the regeneration of the American elm from cells.  (Canada enters the clonal age. Canadian Broadcasts Corporation (CBC) Radio Archives. Canadian Forestry plans to clone trees. http://www.cbc.ca/archives/Categories/Science-technology/biotechnology/Canada , date: Jan 27, 1975). In 1975, Don served as Senior Advisor in the Environmental Impact Assessment in Environment Canada, Ottawa. This position in the Policy and Program Development Directorate (PPD) supported the Assistant Deputy Minister for Environment Canada.  In 1976 Don became Acting Director of the Integration and Environmental Assessment Branch for the Canadian Forestry Service, Canadian Wildlife Service, Inland Waters and Lands Directorate. He was Secretary of the Scientific, Engineering and Technological Societies in the Service of Canada, the Biological Council of Canada (1974-1977) and for the Canadian Society of Plant Physiologists (1975-1977).

Don was invited in 1977 to join the Institute of Paper Chemistry in Appleton WI where he developed new methods for the cloning and genetic improvement of commercially important conifers. This research was highlighted in 1979 for the 50th Anniversary of the Institute of Paper Chemistry. That year he became Head of the Department of Special Studies responsible for the fast-track training of Executives in the Pulp and Paper Industry. Don served on a National Academy of Sciences and World Bank Committee on Biomass assessing biotechnologies for agricultural crops being developed in India (1980). 

Don joined the University of California at Davis in 1981 as Professor and Chairman of the Pomology Department. This Department served the California fruit and nut industry with mission-oriented research, teaching, and service through Extension and Farm Advisors. His research led to patents on somatic polyembryogenesis, diploid parthenogenesis, and the on cryopreservation of cells. By 1995, patent licensing enabled the cloning and field planting of 36,892 Douglas-fir, 1250 Norway spruce and 27,866 loblolly pine clones. Some 500 elite clonal genotypes were cryopreserved.Further refinements and innovations by industry established a prototype “industrial forest”. With other colleagues, foreign genes including those from fireflies were introduced into conifer cells.

Don completed his term as Chairman in 1986. A new laboratory was set up in Environmental Horticulture for basic research on horticultural crops. Cell suspensions were used to clone cherry rootstocks and develop parthenocarpic fruit tissues in vitro. Seasonal changes in amino acids in pistachio crops provided insights into how mineral deficiencies controlled nut development and contributed to alternate bearing. Bud failure in almond crops was characterized by state-network changes in amino acid metabolism. US AID invited Don in 1989 to train personnel in plant propagation in support of cottage industries at the Royal Chitralada Palace in Bangkok, Thailand. Don Co-Directed a NATO ASI conference in Spain on Basic and Applied Approaches to Plant Aging. From 1996 to 2003 He served as an adjunct Professor with the Biomass Resource Center, University of California, Forest Products Laboratory, Berkeley CA.

A project on tissue engineering in simulated microgravity was funded by NASA (1995-1997).  It demonstrated the production of an anti-cancer drug (taxol, paclitaxel) in suspension cultures of egg cells of female Taxus brevifolia. Cultures employed bioreactors designed for the Space Shuttle and International Space shuttle (ISS). Patents were files for the recovery of taxol from other conifers by various methods.   

Don served on the Scientific Working Group for the Biotechnology Facility for the International Space Station (ISS) (1999-2000). A candidate free-flying satellite project (EUREKA) was approved for flight in an orbit between Earth and the ISS. (Eureka Poster). This project was supported by Daimler Benz Aerospace and Boeing and represented one of several exploratory springboards for commercial investment in space. Delays in the completion of the ISS in 2001 cancelled the manifest.  In 2003, NASA’s Inventions and Contributions Board granted Don a ‘Space Act Award’ in recognition for inventions and other scientific and technical contributions that helped NASA achieve its aeronautical and space goals. It included patents related to the ‘Recovery of taxanes and drugs by biosynthetic surface enrichment with anti-drug magnetic antibodies’.

Don was invited as a US Project Coordinator for the Department, Office of Proliferation and Threat Reduction (2000-2006).  This required working with scientists in the Ukraine previously involved with weapons of mass destruction and now “Working out of the technology and equipment for the control of environmental factors, influence on the population health, ecological safety, and biological productivity of the Ukraine”. All activities were coordinated through STCU (Science and Technology Center Ukraine in Kiev). Two workshops were held at Yalta, Ukraine. One was a NATO Advanced Research Workshop Cell Biology and Instrumentation: UV Radiation, Nitric Oxide and Cell Death in Plants”. The other was an International Strategic Scientific Workshop on ‘Cell Biology of nitric oxide and cell death in plants’ supported by the International association for cooperation with scientists from the newly independent states of the former Soviet Union (INTAS) and by the Federation of European Societies of Plant Biology (FESPB).

Don collaborated on an ISTC project in Tajikistan. ISTC contributes to Fundamental Research, International Programs and Innovation and Commercialization, by linking the demands of international markets with the exceptional pool of scientific talent available in Russia and in the Commonwealth of Independent States. Don serves as a peer reviewer of research proposal in agriculture for the Georgian National Science foundation (Tiblisi).

At Davis, Don’s laboratory demonstrated that the fate of arginine N contributed to the formation of nitric oxide in stressed plant cells and how saplings under shaded forest conditions prepared for winter dormancy. In angiosperms and gymnosperms, nitric oxide bursts preceded ethylene release and initiated programmed cell death (apoptosis). In 2009, a new hypothesis was proposed to show how arginine, nitric oxide, and the indispensible amino acids may have contributed to the cure of critically ill sailors in Jacques Cartier’s crew suffering from scurvy in the severe winter of 1536.

Don returned to studies on the intermediary N metabolism of conifers. Shaded spruce saplings entering winter dormancy were shown to divert arginine N to guanidino compounds. In buds of terminal shoots, guandinoacetic acid labeled in the carbon-1 position underwent transamidinations leading to the formation of radioactive glycine and carbon dioxide. Transamidination reactions are not currently reported in textbooks in plant physiology and biochemistry. Feedback loops recycled the products of [1-14C]-guanidinoacetic acid when arginine-rich proteins in buds were being turned over. Transamidination reactions amplified core physiological functions of the C2 cycle. Results ruled out other fates of guanidinoacetic acid and provided new insights into roles of guanidino compounds as respiratory inhibitors.

By 2010, Don’s research demonstrated that embryonic conifer cell cycles could bypass embryonic development and precociously express female parthenogenetic apomixis and male androsporogenesis in culture flasks as prototype artificial sporangia (AS). Under field conditions these expressions of asexual and sexual reproduction occur in trees only after decades of maturity under field conditions. Bringing forward female and male sporogenesis to embryonic cells demonstrated “progenesis” coupled with the seasonal separation of gender expression in two monoecious genotypes. The seasonal gender separation represents a case of “dichogamy”.

An AS offers new opportunities to impose temperature-controlled feedforward and feedback bioprocess controls. It serves a teaching and research laboratory for exploring factors responsible for different cell cycles, asexual and sexual reproduction and for controlling the alternation of generations. New algorithms initiating cell and life cycles may be obtained by simulating ancient environments or by imposing scenarios of future climate change. Bioprocess controls should make it possible to learn more about the timing and expressions of large numbers of genes and to develop ontogenetic compression algorithms having footprints that recall past or initiate new life cycles over a wide range of environment conditions.

Don trained and worked with 24 Post-doctoral Fellows and Visiting Scientists who contributed to research and publications. They are recognized by their contributions as co-authors in publications and patents. Research continues on parthenogenetic apomixis and spore development in embryonal cells continues for Picea, Araucaria, Taxus, and Ephedra species.

© UC Davis | Prof. Don Durzan, Department of Plant Sciences | One Shields Ave | Davis, CA 95616 | Last update: August 28, 2015