Faculty Profiles

Dr. Timothy Mullkey

Timothy J. Mulkey

Associate Professor

Ph.D., Ohio State University

Co-Editor, Bioscene - Journal of College Biology Teaching 1998-2005
Caleb Mills Distinguished Teaching Award, 2003
Orr E. Reynolds Distinguished Service Award, American
     Society for Gravitational and Space Biology, 2001
Educational Excellence Award, College of Arts and Sciences, 2001

Phone: 812-237-2418

E-mail: Timothy.Mulkey@indstate.edu

Office: Science Building 259

Research Interests: plant physiology; hormones and calcium in the control of plant growth, development, and tropic responses.

The interaction of five classes of hormones and of several growth regulating factors controls growth, development, and reproduction, as well as a plant's response to environmental stimuli such as light and gravity. Before significant progress can be achieved in plant molecular biology, the mechanism of plant growth regulator action must be determined. In Dr. Mulkey's laboratory, research is being conducted using the gravitational response of maize roots to study the mechanism of growth.

Presently, he is investigating the role of calcium and calcium-binding proteins in the control of growth and gravitropism. Evidence suggests that calcium plays a major role in regulating a number of interrelated processes intrinsic to cellular expansion, division, and orientation. A second area of concern in Mulkey's laboratory is the mechanism by which plant hormones elicit specific responses. High-resolution real-time measurement of growth, video-image computer digitization and analysis of the kinetics of gravicurvature, and biochemical and immunological studies of calmodulin, tubulin, stathmin, and hormone quantities and location within the tissues are being utilized to determine how the interaction of the five plant hormones coordinate the numerous physiological processes associated with growth and development.

He was co-editor of BioScene - Journal of College Biology Teaching from 1998-2005. Dr. Mulkey as a young professor working in the lab.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Selected Publications

Reprints for some publlications are available as PDF files. By accessing the PDF file, the user agrees to abide by all copyright laws and education fair-use regulations.

T.J. Mulkey. 2005. Alteration of growth and gravitropic response of maize roots by lithium. Gravitational and Space Biology 18:2 (in press; PDFDownload PDF - 2.3 meg)

W.J. Brett, R. Ghosh, and T.J. Mulkey. 2004. Exploration of Biological Phenomena. Hayden McNeil, pp.176 + vi. Fourth Edition. ISBN 0-7380-1072-3.

W.J. Brett and T.J. Mulkey. 2004. General Education Course: Is It Relevant? Bioscene 30(3):9-17. ( PDFDownload PDF - 2 meg)

W.J. Brett, R. Ghosh, T.J. Mulkey. 2000. Explorations of Biological Phenomena. McGraw-Hill, New York, NY. ISBN 0-07-244698-6 pp 160, Third Edition.

W.H. Flurkey, M. Kelley, J.P. Hughes, T.J. Mulkey, D.A. Prentice. 1998. Identification of stathmin-like proteins in plants. Plant Physiol. Biochem. 36(6):449-455. ( PDFDownload PDF - 5.8 meg)

Kim, S. Y. and T. J. Mulkey. 1997. Effect of auxin and ethylene on elongation of intact primary roots of maize (Zea mays L.). Journal of Plant Biology 40: 249-255. ( PDFDownload PDF - 562 kB)

W.J. Brett, R. Ghosh, and T.J. Mulkey. 1997. Exploration of Biological Phenomena. Wm.C. Brown Publishers, Dubuque, IA. pp.148 + iv. Second Edition.

Kim, S. Y. and T. J. Mulkey. 1997. Effect of ethylene antagonists on auxin-induced inhibition of intact primary root elongation in maize (Zea mays L.). Journal of Plant Biology 40: 256-260. ( PDFDownload PDF - 354 kB)

S.Y. Kim, T.J. Mulkey. 1995. Hormones and the motor response of root gravitropism. Bioscene 21(2):13-17. ( PDFDownload PDF - 450 kB)

S.Y. Kim, T.J. Mulkey. 1995. Auxin and protein phosphorylation in plants. Bioscene 21(1):7-12. ( PDFDownload PDF - 672 kB)

S.Y. Kim, T.J. Mulkey. 1994. Auxin movement during root gravitropism. Bioscene 20(1):7-11. ( PDFDownload PDF - 486 kB)

K.L. Rukes, T.J. Mulkey. 1994. Measurement of the effects of light quality and other factors on the rate of photosynthesis. Bioscene 20(3):7-11. ( PDFDownload PDF - 756 kB)

K.L. Rukes, T.J. Mulkey. 1993. Hormonal regulation of cotyledon senescence. Bioscene 19(3):10-15. ( PDFDownload PDF - 888 kB)

T.J. Mulkey. 1991. Modification of gravitropic sensitivity of roots: a laboratory exercise. Bioscene 17(1):3-7. ( PDFDownload PDF - 602 kB)

T.J. Mulkey. 1991. Visualizing acid efflux patterns during tropistic curvature: a laboratory exercise. Bioscene 17(1):8-12. ( PDFDownload PDF - 644 kB)

M.O. Oster, T.J. Mulkey, W.J Brett. 1991. Biological Explorations II. Wm.C. Brown Publishers, Dubuque, IA. pp.351 + iv. ISBN 0-697-14441-0.

W.J. Brett, M.O. Oster, T.J. Mulkey. 1990. Biological Explorations I. Wm.C. Brown Publishers, Dubuque, IA. pp.308 + v. ISBN 0-697-13475-X.

Lee, J. S., K. H. Hasenstein, T. J. Mulkey, R. L. Yang, and M. L. Evans. 1990. Effects of abscisic acid and xanthoxin on elongation and gravitropism in primary roots of Zea mays. Plant Science 68: 17-26. ( PDFDownload PDF - 7.8 meg)

Kim, S. Y. and T. J. Mulkey. 1988. Effects of ethylene antagonists o recovery from auxin-induced inhibition of root elongation. Current Topics in Plant Biochemistry and Physiology 7: 228. ( PDFDownload PDF - 110 kB)

Mulkey, T. J., D. R. Poling, S. Y. Kim, and M. L. Evans. 1988. Effects inoethoxyvinylglycine on root gravitropism in maize. Current Topics in Plant Biochemistry and Physiology 7: 226. ( PDFDownload PDF - 98 kB)

Vaughn, M. A., T. J. Mulkey, and C. W. Goff. 1987. Localization of calcium in roots and microsomal membranes of maize by direct pyroantimonate precipitation. Journal of Histochemistry and Cytochemistry 35: 781-788. ( PDFDownload PDF - 18.8 meg)

T.J. Mulkey, M.A. Vaughan. 1986. Auxin and root gravitropism: the state of our knowledge. In Plant Growth Substances 1985, ed. M. Bopp, Springer-Verlag, New York, Berlin, Heidelburg, pp. 241-246. ( PDFDownload PDF - 248 kb)

J.S. Lee, T.J. Mulkey, M.L. Evans. 1984. Inhibition of polar calcium movement and gravitropism in maize roots treated with auxin transport inhibitors. Planta 160:536-543. ( PDFDownload PDF - 605 kb)

J.S. Lee, T.J. Mulkey, M.L. Evans. 1983. Gravity-induced polar transport of calcium across root tips of maize. Plant Physiol. 73: 874-876. ( PDFDownload PDF - 320 kb)

J.S. Lee, T.J. Mulkey, M.L. Evans. 1983. Reversible loss of gravitropic sensitivity in roots following tip application of calcium chelators. Science 220: 1375-1376. ( PDFDownload PDF - 176 kB)

R.A. Andersen, T.J. Mulkey. 1983. The occurrence of chlorophyll C1and C2in the Chrysophyceae. J. Phycol. 19: 289-294. ( PDFDownload PDF - 421 kB)

T.J. Mulkey, M.L. Evans, K.M. Kuzmanoff. 1983. The kinetics of abscisic acid action on root growth and gravitropism. Planta 157: 150-157. ( PDFDownload PDF - 674 kb)

T.J. Mulkey, M.L. Evans. 1982. Suppression of asymmetric acid efflux and gravitropism in maize roots treated with auxin transport inhibitors or sodium orthovanadate. Journal of Plant Growth Regulation 1: 259-265. ( PDFDownload PDF - 10.4 meg)

M.L. Evans, T.J. Mulkey. 1982. Comparative effects of auxin and abscisic acid on growth, hydrogen ion efflux and gravitropism in primary roots of maize, In Plant Growth Substances 1982, ed. P.F. Waring, Academic Press, New York, pp. 33-42. ( PDFDownload PDF - 464 kB)

T.J. Mulkey, K.M. Kuzmanoff, M.L. Evans. 1982. Promotion of growth and hydrogen ion efflux by auxin in roots of maize pretreated with ethylene biosynthesis inhibitors. Plant Physiol. 70: 186-188. ( PDFDownload PDF - 323 kb)

T.J. Mulkey, K.M. Kuzmanoff, M.L. Evans. 1982. Promotion of growth and shift in the auxin dose/response relationship in corn roots treated with aminoethoxyvinylglycine. Plant Science Letters 25: 43-48. ( PDFDownload PDF - 242 kb)

T.J. Mulkey, K.M. Kuzmanoff, M.L. Evans. 1981. The agar-dye method for visualizing acid efflux patterns during tropistic curvatures. What's New in Plant Physiology 12(3): 9-12. ( PDFDownload PDF - 339 kb)

T.J. Mulkey, K.M. Kuzmanoff, M.L. Evans. 1981. Correlations between proton efflux patterns and growth during geotropism and phototropism in maize and sunflower. Planta 152: 239-241. ( PDFDownload PDF - 262 kb)

T.J. Mulkey, M.L. Evans. 1981. Geotropism in corn roots: evidence for its mediation by differential acid efflux. Science 212 (4490): 70-71. ( PDFDownload PDF - 192 kB)

M.L. Evans, T.J. Mulkey, M.J. Vesper. 1980. Auxin action on proton influx in corn roots and its correlation with growth. Planta 148: 510-512 ( PDFDownload PDF - 230 kb)