Marc A. Cohn
493 Life Sciences Bldg.
Baton Rouge, LA 70803
Phone: (225) 578-1322
Fax: (225) 578-1415
B.A. in Biology, Northeastern University, Boston
M.S. in Plant Physiology, Cornell University
Ph.D. in Plant Physiology, Cornell University
Areas of Specialization/Research
Seed Physiology/Weed Science
Mechanisms of seed dormancy
Physiological ecology of seed dormancy
Mechanisms of recalcitrant seed death
PLHL/BIOS 4444. Seed Physiology. An integrated molecular/genetic, biochemical and
physiological approach to germination, dormancy, vigor and viability, as well as recalcitrance
and seed development.
PLHL 7067. Professional Development for Plant Scientists. An introduction to applications of the scientific method, navigating and evaluating the scientific literature, manuscript & grant preparation, preparing for oral presentations and exams, philosophy of graduate teaching and mentoring .
PLHL/BIOS 7061. Plant Growth & Development. 2 - 3 weeks of guest lectures about seed biology.
Selected Refereed Journal Articles
Chappell, J.H., Y. Wang, M.A. Cohn. 2015. Recalcitrant and orthodox Spartina seeds or isolated embryos exhibit similar leachate patterns immediately following desiccation. Seed Science Research 25: 247-254.
Ziska, L.H., D.R. Gealy, N. Burgos, A.L. Caicedo, J. Gressel, A.L. Lawton-Rauh, L.A. Avila, G. Theisen, J. Norsworthy, A. Ferrero, F. Vidotto, D.E. Johnson, F.G. Ferreira, E. Marchesan, V. Menezes, M.A. Cohn, S. Linscombe, L. Carmona, R. Tang, and A. Merotto Jr. 2015. Weedy (red) rice: an emerging constraint to global rice production. Advances in Agronomy 129: 181-228.
Subudhi, P.K., A. Parco, P.K. Singh, T. DeLeon, R. Karan, H. Biradar, M.A. Cohn, D.S. Brar, T. Sasaki. 2012. Genetic architecture of seed dormancy in U.S. weedy rice in different genetic backgrounds. Crop Science 52:2564-2575.
Oard, S., J. Ham, M.A. Cohn. 2012. Thionins - Nature's weapons of mass protection. pp. 415-443. In R. Rajasekaran, R.W. Cary, J.M. Jaynes, E. Montesinos (Eds) Small Wonders: Peptides for Disease Control. American Chemical Society Symposium Series 1095. American Chemical Society, Washington, DC.
Chappell, J.H., M.A. Cohn. 2011. Corrections for interferences and extraction conditions make a difference: use of the TBARS assay for lipid peroxidation of orthodox Spartina pectinata and recalcitrant Spartina alterniflora seeds during desiccation. Seed Sci. Res. 21: 153-158.
Gianinetti, A., M.A. Cohn. 2008. Seed dormancy in red rice. XIII. Interaction of dry afterripening and hydration temperature. Seed Science Research 18: 151-159.
Gianinetti, A., M.A. Cohn. 2007. Seed dormancy in red rice. XII. Population based analysis of afterripening with a hydrotime model. Seed Science Research 17: 253-271.
Kucera, B., M.A. Cohn, G. Leubner Metzger. 2005. Plant hormone interactions during seed dormancy release and germination (Invited Review) Seed Science Research 15: 281-307.
Cohn, M. A. 2002. Seed dormancy in red rice. A balance of logic and luck. Weed Science 50:261 - 266.
Footitt, S. and M. A. Cohn. 2001. Developmental arrest: from sea urchins to seeds. Seed Science Research 11:3 - 16.
Doherty, L. C. and M. A. Cohn. 2000. Seed dormancy in red rice (Oryza sativa). XI. Commercial liquid smoke elicits germination. Seed Science Research 10: 415 - 421.
Oard, J.; M. A. Cohn; S. Linscombe; D. Gealy; K. Gravois. 2000. Field evaluation of seed production, shattering and dormancy in hybrid populations of transgenic rice (Oryza sativa) and the weed, red rice (Oryza sativa). Plant Science 157: 13 - 22.
Cohn, M. A. and H. W. M. Hilhorst. 2000. Alcohols that break seed dormancy: the anesthetic hypothesis, dead or alive? in J.D.Viemont and J.Crabbe (eds) Dormancy in Plants: From Whole Plant Behaviour to Cellular Control. CAB Publishing, Wallingford. pp 259 - 274.
Hilhorst, H. W. M. and M. A. Cohn. 2000. Are cellular membranes involved in the control of seed dormancy? in J.D.Viemont and J. Crabbe (eds) Dormancy in Plants: From Whole Plant Behaviour to Cellular Control. CAB Publishing, Wallingford. pp 275 - 289.
Program Milestones (Reprints avaliable upon request)
By using ‘sister species’ comparative physiology in Spartina, showed that oxidative stress symptoms are a common response to seed maturation drying and not a cause/effect of recalcitrant seed death (e.g. Chappell, J.H., Y. Wang, M.A. Cohn. 2015. Recalcitrant and orthodox Spartina seeds or isolated embryos exhibit similar leachate patterns immediately following desiccation. Seed Science Research 25: 247-254.)
Identified a suite of three dozen heat stable proteins putatively required for seed desiccation tolerance using the Spartina comparative proteomics system. (Wang, Chen and Cohn. 2016. In preparation)
Proteomic bioinformatics revealed that proteins usually associated with breaking of seed dormancy by moist chilling are actually generic responses of plant tissue to cold stress (Wang, Chen and Cohn. 2016. In preparation)
First report of rapid seed acidification after contact with dormancy-breaking chemicals (Footitt, S.; M. A. Cohn. 1992. Seed dormancy in red rice. VIII. Embryo acidification during dormancy- breaking and subsequent germination. Plant Physiol 100:1196 - 1202).
First report of rapid glycolytic activation after contact with dormancy-breaking chemicals. This is still the most rapid biochemical/molecular response to a dormancy-breaking chemical in the published literature (Footitt, S.; M. A. Cohn. 1995. Seed dormancy in red rice. IX. Levels of fructose 2,6-bisphosphate in red rice embryos during dormancy-breaking and germination. Plant Physiol 107:1365 - 1370).
First to report that applied chemicals must be metabolized before they break dormancy. Kinetics of metabolites, inhibitor studies, enzymology (Footitt, S.; D. Vargas; M. A. Cohn. 1995. Seed dormancy in red rice. X. A 13-C NMR study of metabolism of dormancy-breaking chemicals. Physiol Plant 94:667 - 671).
First use of computational chemistry to the model and design of dormancy-breaking chemicals (Cohn, M. A. 1997. QSAR modeling of dormancy-breaking chemicals. Pp. 289 - 295 in RH Ellis et al. (ed). Basic and Applied Aspects of Seeds. Proc 5th International Workshop on Seeds. Kluewer; Cohn, M. A.; K. L. Jones; L. A. Chiles; D. F. Church. 1989. Seed dormancy in red rice. Vll. Structure-activity studies of germination stimulants. Plant Physiol 89:879 - 882).
First report of highly specific chemical structure requirements for dormancy-breaking chemicals (Cohn, M. A.; D. F. Church; J. Ranken; V. Sanchez. 1991. Hydroxyl group position governs activity of dormancy-breaking chemicals. Plant Physiol S-96:63;
Cohn, M. A. 1993. Chemical structure versus physiological activity: studies of dormancy-breaking chemicals for seeds. SEARCH 28:1 - 6).
First report of low-moisture content inhibition of dry-afterripening (Leopold, A. C.; R. Glenister; M. A. Cohn. 1988. Relationship between water content and afterripening in red rice. Physiol Plant 74:659 - 662).
First successful demonstration of application of a dormancy-breaking chemical (nitrogen oxides) to unimbibed seeds (Cohn, M. A.; L. Castle. 1984. Dormancy in red rice. IV. Response of unimbibed and imbibing seeds to nitrogen dioxide. Physiol Plant 60:552 - 556).
Discovered a new class of dormancy-breaking chemicals: monocarboxylic acids (Cohn, M. A.; L. A. Chiles; J. A. Hughes; K. J. Boullion. 1987. Seed dormancy in red rice. Vl. Monocarboxylic acids: a new class of pH-dependent germination stimulants. Plant Physiol 84:716 - 719).
First report of chemical lipophilicity, nature of functional groups, or molecular size controlling the efficacy of dormancy-breaking chemicals (Cohn, M. A.; K. L. Jones; L. A. Chiles; D. F. Church. 1989. Seed dormancy in red rice. Vll. Structure-activity studies of germination stimulants. Plant Physiol 89:879 - 882).
First reports of general principal of pH dependence for dormancy-breaking chemicals which are weak acids or bases (Cohn, M. A.; D. L. Butera; J. A. Hughes. 1983. Seed dormancy in red rice. III. Response to nitrite, nitrate, and ammonium ions. Plant Physiol 73:381 - 384; Cohn, M. A.; J. A. Hughes. 1986. Seed dormancy in red rice. V. Response to azide, cyanide, and hydroxylamine. Plant Physiol 80:531 - 533; Cohn, M. A.; L. A. Chiles; J. A. Hughes; K. J. Boullion. 1987. Seed dormancy in red rice. Vl. Monocarboxylic acids: a new class of pH-dependent germination stimulants. Plant Physiol 84:716 - 719).
First report of long-term red rice seed survival under flooded conditions in the absence of soil under laboratory conditions (Cohn, M. A.; J. Hughes; D. Butera.1984. Dormancy and viability of red rice during maturation and storage. Plant Physiol S-75:68