John Bukovac

John Bukovac

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Professor Emeritus
Department of Horticulture



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Joined the department





Dr. agr. honoris causa, University of Bonn, 1995
Postdoctoral Student, Oxford & Bristol Universities, 1965-1966
Ph.D. Michigan State University, 1957
M.S., Michigan State University, 1954
B.S. (With Honors), Michigan State University, 1951


Dr. Martin J. Bukovac served in the Department of Horticulture for forty years in research and teaching. He conducted both applied and basic research on the role of plant hormones on flower formation, fruit growth and development, and on the mechanisms of chemical penetration through plant cuticles. His work has led to several patents and practices currently in use by the horticultural industry, namely, regulation of flowering and fruit growth, promotion of fruit abscission, fruit thinning, and more efficient application and use of pesticide chemicals.

He has served as mentor to 37 graduate students and 45 postdoctoral and visiting scientists. Bukovac was a U.S. National Science Foundation Senior Postdoctoral Fellow at Oxford and Bristol Universities, was elected to the U.S. National Academy of Sciences in 1983, received an honorary doctorate degree from the University of Bonn in Germany in 1995 and was elected to the American Society for Horticultural Science Hall of Fame in 2001.

Bukovac is a member of numerous professional organizations: he served as President of the American Society for Horticultural Science and received awards from the American Horticultural Society, American Society for Horticultural Science, Michigan State Horticultural Society, American Society of Plant Physiologists, and Society for Engineering and Agriculture, Food and Biological Systems.

He frequently served as a guest speaker at symposia and congresses. He presented the keynote address in observance of the 75th Anniversary of the East Malling Research Station, England, and was selected as the USDA B. Y. Morrison Lecturer, the William Henry Hatch Memorial Lecturer, National Academy of Sciences Exchange Lecturer to Yugoslavia, Distinguished Lecturer, Department of Sciences and Technology in China and Foreign Scientific Lecturer, Nara Institute of Science and Technology, Nara, Japan. He served as a short-term visiting professor at the universities of Guelph, New Mexico State, Oregon State and Ohio State. In 1986 Bukovac presented the undergraduate commencement address at Michigan State University; the University honored him by bestowing the Distinguished Faculty Award in 1972, and designation of University Distinguished Professor in 1992. In 1995, he conducted research in Germany having won the Humboldt Prize for Senior American Scientists. More recently he was awarded the Gold Veitch Memorial Medal by the Royal Horticultural Society, London (2003), and the Spiridon Brusina Medal by the Croatian Society for Natural Sciences, Zagreb (2004).

In retirement Dr Bukovac continues to maintain a limited research program by writing and working with colleagues and visiting scientists.


Publications During Retirement

  • Nakayama, M., T. Yokota, R. Sohma, L.N. Mander, B. Twitchin, H. Komatsu, H. Matsui and M.J. Bukovac. 1996. Gibberellins in immature seed of Prunus cerasus: Structure, determination and synthesis of gibberellin, GA95 (1,2-didehydro-GA20). Phytochemistry 42(4):913-920.
  • Black, B. and M.J. Bukovac. 1996. Plant growth regulator application technology, uptake and action. In: Marb, K.M., D.K. Andrews, G.A. Lang and K. Mullinix (eds.), Tree Fruit Physiology: Growth and Development, pp. 41-50. Washington State Fruit Commission, Yakima, Washington.
  • Kollár, G. and M.J. Bukovac. 1996. The effect of ethrel and silaid on facilitating machine harvest of sour cherry. In: Hampson, C.R., R.L. Anderson, R.L. Perry and A.D. Webster (eds.), Proceedings of the International Cherry Symposium, Acta Horticulturae, No. 410, p. 345-350. International Society for Horticultural Science, Netherlands.
  • Bukovac, M.J. 1996. Growth regulation in cherry: the past and the opportunities for the future. Mich. State Hort. Soc.Ann. Rept. 126:212-215.
  • Stopar, M., B.L. Black, and M.J. Bukovac. 1997. The effect of NAA and BA on carbon dioxide assimilation by shoot leaves of spur-type ‘Delicious' and ‘Empire' apple trees. J. Amer. Soc. Hort Sci. 122(6):837-840.
  • Fader, R.G. and M.J. Bukovac. 1997. Triton X-45: A unique effect on growth regulator sorption by and penetration of isolated plant cuticles. In: Pesticide Formulations and Application Systems: 17th Volume, ASTM STP 1328, G. Robert Goss, Michael J. Hopkinson, and Herbert M. Collins, Eds., American Society for Testing and Materials, p. 310-326.
  • Bukovac, M.J. 1998. Chemical promotion of fruit abscission facilitates machine harvest of cherries. In: Citrus Abscission Workshop, Florida Department of Citrus, Lake Alfred, FL, p. 37-51.
  • Bukovac, M.J. 1998. The plant surface: A defining factor in performance of plant bioregulators. In: J.L. Guardiola, J.L. Garcia Martinez and J.D. Quinlan (Eds.), Proc. Eight Int. Symp. Plant Regulators. Fruit Prod. Acta. Hortic. 463:23-28.
  • Reichard, D.L., J.A. Cooper, M.J. Bukovac and R.D. Fox. 1998. Using a videographic system to assess spray droplet impaction and reflection from leaf and artificial surfaces. Pestic. Sci. 53:291-299.
  • Petracek, P.D., R.G. Fader, M. Knoche and M.J. Bukovac. 1998. Surfactant-enhanced penetration of benzyladenine through isolated tomato fruit cuticular membranes. J. Agric. Food Chem. 46(6):2346-2352.
  • Knoche, M., M.J. Bukovac, S. Nakagawa and G.D. Crabtree. 1998. Spray application factors and plant growth regulator performance: I. Bioassays and biological response. Pestic. Sci. 54:168-178.
  • Ohkouchi, T., M.J. Bukovac and G. Noga. 1998. Improving calcium penetration: Measurement and factors affecting cuticular penetration. In: M. Blanke (ed.), Second Workshop on Pome Fruit. Acta. Hortic. 466:23-28.
  • Brazee, R.D., M.J. Bukovac, J.A. Cooper and D.L. Reichard. 1999. Droplet shape oscillations: Effects on spray impaction and retention and fourier analysis of their natural frequencies. Trans. Amer. Soc. Agric. Eng. 42(2):319-325.
  • Knoche, M. and M.J. Bukovac. 1999. Spray applications factors and plant growth regulator performance: II. Foliar uptake of gibberellic acid and 2,4-D. Pestic. Sci. 55:166-174.
  • Knoche, M. and M.J. Bukovac. 2000. Spray application factors and plant growth regulator performance: V. Biological response as related to foliar uptake. Aspects Appl. Biol. 57:257-265.
  • Knoche, M., N.K. Lownds and M.J. Bukovac. 2000. Spray application factors and plant growth regulator performance: IV. Dose response relationships. J. Amer. Soc. Hort. Sci. 125(2):195-199.
  • Knoche, M., M.J. Bukovac. 2000. Spray application factors and plant growth regulator performance: III. Interaction of daminozide uptake, translocation and phytotoxicity in bean seedlings. Pest. Manag. Sci. 56:43-48.
  • Bukovac, M.J., M. Schroeder and G. Noga. 2000. Effects of fruit thinning sprays of NAA and BA on cropping of ‘Elstar' and ‘Gloster' apples. Acta. Hortic. 514(4):91-98.
  • Black, B.L., M.J. Bukovac and M. Stopar. 2000. Intraspur fruit competition and position influence fruit size at harvest and response to chemical thinning agents in spur-type ‘Delicious' apple. Acta Hortic. 527:119-125.
  • Wells, J.M. and M.J. Bukovac. 2000. Flowering and fruiting characterisitics of ‘Stanley' plum. Acta Hortic. 527:199-205.
  • Retamales, J.B., E.J. Hanson and M.J. Bukovac. 2000. GA3 as a flowering inhibitor in blue berries. Acta Hortic. 527:147-151.
  • Brazee, R.D., R.D. Fox, J.A. Cooper and M.J. Bukovac. 2000. Dynamic surface tension in relation to droplet impaction interactions with leaf surfaces. Acta Hortic. 527:65-71.
  • Knoche, M., Petracek, P.D. and M.J. Bukovac. 2000. Finite dose diffusion studies: I. Characterizing cuticular penetration in a model system using NAA and isolated tomato fruit cuticles. Pest. Manag. Sci. 56:1005-1015.
  • Knoche, M. and M.J. Bukovac. 2000. Finite dose diffusion studies: II. Characterizing cuticular penetration in a model system using NAA and isolated tomato fruit cuticles. Pest. Manag. Sci. 56:1005-1015.
  • Knoche, M., Peschel, S., Hinz, M. and M.J. Bukovac. 2000. Studies on water transport through the sweet cherry fruit surface: characterizing conductance of the cuticular membrane using pericarp segments. Planta 212:127-135.
  • Tamura, H., Knoche, M. and M.J. Bukovac. 2001. Evidence for surfactant solubilization of plant epicuticular wax. J. Agric. Food Chem. 49:1809-1816.
  • Tamura, H., Knoche, M., Hayashi, Y. and M.J. Bukovac. 2001. Selective solubilization of tomato fruit epicuticular wax constituents by Triton X-100 surfactant. J. Pesticide Sci. 26:16-20.
  • Petracek, P.D. and M.J. Bukovac. 2001. Temperature effects on cuticular sorption and desorption of an octylphenoxy surfactant. In: 6th Int. Symp. on Adjuvants for Agrochemicals, ed. H. deRuiter, pp. 61-67, ISAA Foundation, Netherlands.
  • Knoche, M. and M. J. Bukovac. 2001. Finite dose diffusion studies: III. Effects of temperature, humidity and deposit manipulation on NAA penetration through isolated tomato fruit cuticles. Pest. Manag. Sci. 57:737-742.
  • Knoche, M., Peschel, T., Hinz, M. and M.J. Bukovac. 2001. Studies on water transport through the sweet cherry fruit surface: II. Conductance of the cuticle in relation to fruit development. Planta 213: 927-936.
  • Cooper, J., Fox, R.D., Dexter, R.D., and M.J. Bukovac. 2001. Dynamic surface tension of selected nonionic agricultural surfactants at surface ages relevant to component processes in spray application, Pesticide Formulations and Application Systems: A New Century for Agricultural Formulations, Twenty First Volume, ASTM STP 1414, J. C. Mueninghoff, A. K. Viets, and R. A. Downer, Eds., American Society for Testing and Materials, West Conshohocken, PA, 2001. pp. 50-60.
  • Bukovac, M.J., J.A. Cooper, R.E. Whitmoyer and R.D. Brazee. 2002. Spray application plays a determining role in performance of systemic compounds applied to the foliage of fruit plants. In: M. Tagliavini, M. Toselli, L. Bertschinger, P. Brown, D. Neilsen and M. Thalheimer (eds.), Proc. Int. Symp. Foliar Nutrition Perennial Fruit Plants. Acta Hort. No. 594, Int. Soc. Hort. Sci., Leuven, Belgium. pp. 65-75.
  • Bukovac, M.J., J.A. Cooper, R.E. Whitmoyer and R.D. Brazee. 2003. Pesticide Delivery: Multiple role of adjuvants in foliar application of systemic compounds. In: Pesticide Formulations and Delivery Systems: Meeting the Challenges of the Current Crop Protection Industry, ASTM STP 1430, R.A. Downer, J.C. Mueninghoff and G.C. Volgas, Eds., American Society for Testing and Materials International, West Conshohocken, PA, 2003.
  • Bukovac, M.J., Fader, R.G., and Luque, P. 2003. Effects of urea and ammonium nitrate on penetration of NAA through enzymatically isolated tomato fruit cuticular membranes. Pesticide Formulations and Application Systems: 23rd International Symposium, ASTM STP 1449, G. Volgas, R. Downer, and H. Lopez, Eds., ASTM International, West Conshohocken, PA, 2003. pp. 15-31.
  • Knoche, Moritz and Martin J. Bukovac. 2004. Effect of Triton X-100 concentration on NAA penetration through the isolated tomato fruit cuticular membrane. Crop Protection 23:141-146.
  • Harz, Martin, Moritz Knoche and Martin J. Bukovac. 2003. Epidermal segments: a useful model system for studying water transport through fruit surfaces. HortScience 38(7):1410-1413.
  • Knoche, Moritz, Marco Beyer, Stefanie Peschel, Boyko Oparlakov, and Martin J. Bukovac. 2004. Changes in strain and deposition of cuticle in developing sweet cherry fruit. Physiologia Plantarum 120:667-677.
  • Ungsa, M., K. Kato, K. Takemura, T. Hori, H. Ohara, K. Ohkawa, H. Matsui and M.J. Bukovac. 2003. Effects of the combination of gibberellic acid and ammonium nitrate on the growth and quality of seedless berries in ‘Delaware' grape. J. Jap. Soc. Hort. Sci. 72:366-371.
  • Brazee, R.D., M.J. Bukovac and H. Zhu. 2004. Diffusion model for plant cuticular penetration by spray-applied weak organic acid bioregulator in presence or absence of ammonium nitrate. American Society of Agricultural Engineers 47(3):629-635.
  • Bukovac, Martin J. 2005. Maximizing performance of plant growth regulators by improving spray application. HortTechnology 15(2):222-231.
  • Bukovac, Martin J. 2005. The cuticular membrane: a dynamic interface between plant and environment. Periodicum Biologorum, 107(1):1-9.
  • Zabadal, Thomas J. and Martin J. Bukovac. 2006. Effect of CPPU on fruit development of selected seedless and seeded grape cultivars. HortScience 41(1):154-157.
  • Bukovac, M.artin J., Paolo Sabbatini and Philip G. Schwallier. 2006. Modifying alternate bearing of spur-type ‘Delicious' apple with ethephon. HortScience 41(7): 1606-1611.
  • Sun, Lingxia, M. John Bukovac, Philip L. Forsline and Steven van Nocker. 2008. Natural variation in fruit abscission-related traits in apple (Malus). Euphytica 165(1): 55-67
  • Bukovac, Martin J. and Paolo Sabbatini, Philip G. Schwallier, and Michael Schroeder. 2008. Characterizing the interaction between NAA and BA on apple fruit abscission and development. HortScience 43(6):1794-1801