Davies recent research has been on the role of plant hormones in stem growth, whole-plant senescence, tomato ripening and potato tuberization. More recently he has been undertaking metabolomic analyses of grapes and apples in relation to disease resistance and metabolic disorders. However he is now in retirement and no longer accepting research students.
Outreach and Extension Focus
Davies spent one year (2011-2012) as a Jefferson Fellow in residence at the Department of State in Washington DC, serving as a senior science adviser to the office of Agriculture, Biotechnology and Textile Trade Affairs in the Bureau of Economics and Business. He was particularly involved as an adviser on biotech (GMO) crops within the office, including involvement in a Foreign Service Institute course on biotech crops for foreign service personnel. In addition he visited nine countries and delivered 26 lectures or presentations on biotech crops at universities, institutes, academies, farmers groups and schools, as well as to government officials in these countries. During his overseas trips he conducted several interviews with journalists and on TV resulting in extensive reports on biotech crops on local newspapers. In November he was recalled to the Philippines as an expert witness in a court hearing on Bt eggplant trials. On returning to Cornell Davies has become involved in International Agriculture in International Programs. The Fellow position continues with Davies in the role of consultant, most recently in biotech crop outreach in Southern Africa in 2014. In 2014 he spent 3 months on biotech crop outreach in Hawaii, and continues lecturing on biotech crop education whenever possible.
Teaching Focus
Professor Davies was appointed at Cornell with the expressed purpose of teaching Plant Physiology to students in agriculture and horticulture because of his agronomy background and research experience in basic plant physiology. He taught Plant Function and Growth from 1970 until 2015, keeping it up to date but at an appropriate level for undergraduate students. After three years teaching introductory biology to non majors his emphasis (2009-2015) moved to encouraging students to learn how advances in biology affect their lives with a course Issues in Social Biology, Diet to Disease, DNA to Deforestation, subtitled Biology in the News, where the emphasis is self-discovery via articles in the media rather than rote learning of biological facts. He was also involved in teaching in International Agriculture including Agriculture in Developing Nations and The GMO Debate. Now emeritus he continues involvement in The GMO Debate.
Selected Publications
- Davies, P. J. and Muehlbauer F. 2020. Peas. In Vegetable Crop Physiology, 2nd edition, Wien, H. C. and Stützel, H. eds. CABI, Wallingford UK. pp. 287-316. ISBN-13: 978-1786393777
- Tassoni, A., Zappi, A., Melucci D., M. Bruce I. Reisch, B. I. and Davies, P. J. 2019. Seasonal changes in amino acids and phenolic compounds in fruits from hybrid cross populations of American grapes differing in disease resistance. Plant Physiology and Biochemistry, 135, 182-193.
- Tamas, I. A. & Davies, P. J. 2016. Dynamics and control of phloem loading of indole-3-aceticacid in seedling cotyledons of Ricinus communis. Journal of Experimental Botany, 67, 4755-4765.
- Yang, X., Brown, S. K., & Davies, P. J. (2013). The content and in vivo metabolism of gibberellin in apple vegetative tissues. Journal of the American Society for Horticultural Science. 138:17278-17283.
- Davies, P. J., & Gan, S. (2012). Towards an integrated view of monocarpic plant senescence. Russian Journal of Plant Physiology. 59:476-478.
- Sklensky, D. E., & Davies, P. J. (2011). Resource partitioning to male and female flowers of Spinacia oleracea L. in relation to whole-plant monocarpic senescence. JXB: Journal of Experimental Botany. 62:4323Ð4336.
- Davies, P. J. (ed.) 2010. Plant Hormones: Biosynthesis, Signal Transduction, Action! Revised 3rd ed. Springer: Dordrecht, The Netherlands. 801 pp. ISBN 978-1-4020-2684-3 (This is the authoritative text in the field, assembled and produced by PJD. Three previous editions: 2004, 1995 & 1987. Also translated into Chinese 2008)
- Silva, T. M., & Davies, P. J. (2007). Hormone growth responses of roots of shoot height mutants of pea. Physiologia Plantarum. 129:813-821.
- Silva, T. M., & Davies, P. J. (2007). Elongation rates and endogenous indoleacetic acid levels in roots of pea mutants differing in internode length. Physiologia Plantarum. 129:804-812.
- Tassoni, A., Watkins, C. B., & Davies, P. J. (2006). Inhibition of the ethylene response by 1-MCP in tomato suggests that polyamines are not involved in delaying ripening, but may moderate the rate of ripening or over-ripening. JXB: Journal of Experimental Botany. 57:3313–3325.
- Hannapel, D. J., Chen, H., Rosin, F. M., Banerjee, A. K., & Davies, P. J. (2004). Molecular controls of tuberization. American Journal of Potato Research. 81:5-16.
- Ewing, E. E., Simko, I., Omer, E. A., & Davies, P. J. (2004). Polygene mapping as a tool to study the physiology of potato tuberization and dormancy. American Journal of Potato Research. 81:33-41.
- Rosin, F. M., Hart, J. K., Horner, H. T., Davies, P. J., & Hannapel, D. J. (2003). Overexpression of a knotted like homeobox gene of potato alters vegetative development by decreasing gibberellin accumulation. Plant Physiology. 132:106-117.
- Mapes, C. C., & Davies, P. J. (2001). Cytokinins in the ball gall of Solidago altissima and in the gall forming larvae of Eurosta. New Phytologist. 151:203-212.
- Lester D. R., J. J. Ross, P. J. Davies, and J. B. Reid. 1997. Mendel's stem length gene (Le) encodes a gibberellin 3β-hydroxylase. Plant Cell 9: 1435-1443.
