venus flytrap


Dr. Udo Blum

Professor Emeritus


Research Interests

I am presently interested in characterizing and identifying the mechanisms by which allelopathic compounds, specifically phenolic acids (e.g., ferulic acid, p-coumaric acid, vanillic acid, p-hydroxybenzoic acid), released into the soil environment may impact soil chemistry (e.g., soil nutrition, organic pools, sorption and desorption), soil microbiology (e.g., population biology, natural selection, carbon utilization), rhizosphere ecology (e.g., microbial population biology) and population biology (e.g., germination, seedling emergence) and physiology (e.g., mineral nutrition, carbon allocation, water relations, growth) of dicot weeds in no-till agroecosystems.


Publications

Blum, U., and Rice, E. L. 1969. Inhibition of symbiotic nitrogen-fixation by gallic and tannic acid, and possible roles in old-field succession. Torrey Bot. Club 96 : 531-544.

Tingey, D. T., and Blum, U. 1973. Effects of ozone on soybean nodules. J. Environ. Qual. 2:341-342.

Akers, S. W., Anderson, C. E., and Blum, U. 1977. Characterization of vacuolar bodies in Spartina alterniflora: I. Formation, development, morphology, and ultrastructure. Amer. J. Bot. 64:635-640.

Akers, S. W., Anderson, C. E., and Blum, U. 1977. Characterization of vacuolar bodies in Sparatina alterniflora: II. Some physical and chemical properties. Amer. J. Bot. 64:641-648.

Blum, U., and Tingey, D. T. 1977. A study of the potential ways in which ozone could reduce root growth and nodulation of soybean. Atmospheric Environ. 11:737-739.

Letchworth, M. B., and Blum, U. 1977. Effects of acute ozone exposure on growth, nodulation and nitrogen content of ladino clover. Environ. Pollut. 14:303-312.

Blum, U., Seneca, E. D., and Stroud, L. M. 1978. Photosynthesis and respiration of Spartina and Juncus salt marshes in North Carolina: Some models. Estuaries 1:228-238.

Blum, U., and Heck, W. W. 1980. Effects of acute ozone exposures on snap bean at various stages of its life cycle. Environ. Exp. Bot. 20:73-85.

Conn, J. S., Wentworth, T. R., and Blum, U. 1980. Pattern of dioecism in the flora of the Carolinas. Amer. Midl. Natur. 103:310-315.

Kochhar, M., Blum, U., and Reinert, R. A. 1980. Effects of O3 and (or) fescue on ladino clover: interactions. Can. J. Bot. 58:241-249.

Conn, J. S., and Blum, U. 1981. Differentiation of the sexes of Rumex hastatulus in net energy allocation, flowering and height. Torrey Bot. Club. 108:446-455.

Conn, J. S., and Blum, U. 1981. Sex ratio of Rumex hastatulus: the effects of environmental factors and certation. Evolution 35:1108-1116.

Linthurst, R. A., and Blum, U. 1981. Growth modification of Spartina alterniflora Loisel. by the interaction of pH and salinity under controlled conditions. J. Exp. Mar. Biol. Ecol. 55:207-218.

Blum, U., Smith, G. R., and Fites, R. G. 1982. Effects of multiple O3 exposures on carbohydrate and mineral contents of ladino clover. Environ. Exp. Bot. 22:143-154.

Cammen, L. M., Blum, U., Seneca, E. L., and Stroud, L. M. 1982. Energy flow in a North Carolina salt marsh: A synthesis of experimental and published data. ASB. Bulletin 29:111-134.

Hall, A. B., Blum, U., and Fites, R. C. 1982. Stress modification of allelopathy of Helianthus annuus L. debris on seed germination. Amer. J. Bot. 69:776-783.

Montes, R. A., Blum, U., and Heagle, A. S. 1982. The effects of ozone and nitrogen fertilizer on tall fescue, ladino clover, and a fescue-clover mixture. I. Growth, regrowth and forage production. Can. J. Bot. 60:2745-2752.

Kochhar, M., Reinert, R. A., and Blum, U. 1982. Effects of Festuca arundinacea and/or clover Trifolium repens debris and fescue leaf leachate on clover as modified by 0O3 and Rhizoctonia solani. Environ. Pollution 28:255-264.

Blum, U., Heagle, A. S., Burns, J. C., and Linthurst, R. L. 1983. The effects of ozone on fescue-clover forage: Regrowth, yield and quality. Environ. Exp. Bot. 23:121-132.

Blum, U., Mrozek, E., Jr., and Johnson, E. 1983. Investigation of ozone (O3) effects on 14C distribution in ladino clover. Environ. Exp. Bot. 23:369-378.

Dalton, B. R., Blum, U., and Weed, S. B. 1983. Allelopathic substances in ecosystems: Effectiveness of sterile soil components in altering recovery of ferulic acid. J. Chem. Ecol. 9:1185-1201.

Hall, A. B., Blum, U., and Fites, R. C. 1983. Stress modification of Helianthus annuus L. debris on seedling biomass production of Amaranthus retroflexus L. J. Chem. Ecol. 9:1213-1222.

Montes, R. A., Blum, U., Heagle, A. S., and Volk, R. J. 1983. The effects of ozone and nitrogen fertilizer on tall fesuce, ladino clover, and a fescue-clover mixture. II. Nitrogen content and fixation. Can. J. BOt. 61:2159-2168.

Blum, U., Dalton, B. R., and Rawlings, J. O. 1984. Effects of ferulic acid and some of its microbial metabolic products on the radicle growth of cucumber. J. Chem. Ecol. 10:1169-1191.

Seneca, E. D., and Blum, U. 1984. Response to photoperiod and temperature by Spartina alterniflora (Poaceae) from North Carolina and Spartina foliosa from California. Amer. J. Bot. 71:91-99.

Blum, U., and Dalton, B. R. 1985. Effects of ferulic acid, an allelopathic compound, on leaf expansion of cucumber seedlings grown in nutrient culture. J. Chem. Ecol. 11:279-301.

Blum, U., Dalton, B. R., and Shann, J. R. 1985. Effects of various mixtures of ferulic acid and some of its microbial metabolic products on cucumber leaf expansion and dry matter in nutrient culture. J. Chem. Ecol. 11:619-641.

Blum, U., Dalton, B. R., and Shann, J. R. 1985. Effects of ferulic and p-coumaric acids in nutrient culture on cucumber leaf expansion as influenced by pH. J. Chem. Ecol. 11:1567-1582.

Blum, U., Weed, S. B., and Dalton, B. R. 1987. Influence of various soil factors on the effects of ferulic acid on leaf expansion of cucumber seedlings. Plant and Soil 98:111-130.

Dalton, B. R., Weed, S. B., and Blum, U. 1987. Plant phenolic acids in soils: A comparison of extraction procedures. Soil Sci. Soc. Amer. J. 51:1515-1521.

Johnson, E. L., Heck, W. W., Fites, R. C., and Blum, U. 1987. Effects of irradiance on amino and organic acid levels in ladino clover. Environ. Expt. Bot. 27:441-448.

Shann, J. R., and Blum, U. 1987. The uptake of ferulic and p-hydroxybenzoic acids by Cucumis sativus. Phytochemistry 26 : 2959-2964.

Shann, J. R., and Blum, U. 1987. The utilization of exogenously supplied ferulic acid in lignin biosynthesis. Phytochemistry 26:2977-2982.

Waters, E. R., and Blum, U. 1987. The effects of single and multiple exposures of ferulic acid on the vegetative and reproductive growth of Phaseolus vulgaris BBL-290. Amer. J. Bot. 74:1635-1645.

Blum, U., and Shafer, S. R. 1988. Microbial populations and phenolic acids in soils. Soil Biol. Biochem. 20:793-800.

Rebbeck, J., Blum, U., and Heagle, A. S. 1988. Effects of ozone on the regrowth and energy reserves of a ladino clover-tall fescue pasture. J. Applied Ecol. 25:659-681.

Blum, U., Gerig, T. M., and Weed, S. B. 1989. Effects of mixtures of phenolic acids on leaf area expansion of cucumber seedlings grown in different pH Portsmouth A1 soil materials. J. Chem. Ecol. 15:2413-2423.

Blum, U., and Rebbeck, J. 1989. The inhibition and recovery of cucumber roots given multiple treatments of ferulic acid in nutrient culture. J. Chem. Ecol. 15:917-928.

Booker, F. L., Seneca, E. D., and Blum, U. 1989. Effects of weathered fuel oil on solute leakage, respiration and plasmolysis in excised root sections of Spartina alterniflora Loisel. and Limonium carolinianum (Walt.). Britt. Environ. Expt. Bot. 29:249-259.

Dalton, B. R., Blum, U., and Weed, S. B. 1989. Differential sorption of exogenously applied ferulic, p-coumaric, p-hydroxybenzoic, and vanillic acids in soil. Soil Sci. Soc. Amer. J. 53:757-762.

Dalton, B. R., Blum, U., and Weed, S. B. 1989. Plant phenolic acids in soils: Sorption of ferulic acid by soil and soil components sterilized by different techniques. Soil Biol. Biochem. 21:1011-1018.

Gerig, T. M., Blum, U., and Meier, K. 1989. Statistical analysis of the joint inhibitory action of similar compounds. J. Chem. Ecol. 15:2403-2412.

Heagle, A. S., Rebbeck, J., Shafer, S. R., Blum, U., and Heck, W. W. 1989. Effects of long-term ozone exposure and soil moisture deficit on growth of a ladino clover-tall fescue pasture. Phytopathology 79:128-136.

White, R. H., Worsham, A. D., and Blum, U. 1989. Allelopathic potential of legume debris and aqueous extracts. Weed Science 37:674-679.

Klein, K., and Blum, U. 1990. Inhibition of cucumber leaf expansion by ferulic acid in split-root experiments. J. Chem. Ecol. 16 : 455-463.

Klein, K., and Blum, U. 1990. Effects of soil nitrogen level on ferulic acid inhibition of cucumber leaf expansion. J. Chem. Ecol. 16:1371-1383.

Lyu, S.-W., Blum, U., Gerig, T. M., and O'Brien, T. E. 1990. Effects of mixtures of phenolic acids on phosphorus uptake by cucumber seedlings. J. Chem. Ecol. 16:2559-2567.

Lyu, S.-W., and Blum, U. 1990. Effects of ferulic acid, an allelopathic compound, on net P, K, and water uptake by cucumber seedlings in a split-root system. J. Chem. Ecol. 16:2429-2439.

Blum, U., Wentworth, T. R., Klein, K., Worsham, A. D., King, L. D., Gerig, T. M., and Lyu, S.-W. 1991. Phenolic acid content of soils from wheat-no till, wheat-conventional till, and fallow-conventional till soybean cropping systems. J. Chem. Ecol. 17:1045-1068.

Gerig, T. M., and Blum, U. 1991. Effects of mixtures of four phenolic acids on leaf area expansion of cucumber seedlings grown in Portsmouth B1 soil materials. J. Chem. Ecol. 17:29-40.

Holappa, L. D., and Blum, U. 1991. Effects of exogenously applied ferulic acid, a potential allelopathic compound, on leaf growth, water utilization, and endogenous abscisic acid levels of tomato, cucumber, and bean. J. Chem. Ecol. 17:865-886.

Hollingworth, R. G., Blum, U., and Hain, F. P. 1991. The effects of adelgid-altered wood on sapwood conductance of fraser fir Christmas trees. IAWA Bull. 12:235-239.

Shafer, S. R., and Blum, U. 1991. Influence of phenolic acids on microbial populations in the rhizosphere of cucumber. J. Chem. Ecol. 17:369-389.

Bergmark, C. L., Jackson, W. A., Volk, R. J., and Blum, U. 1992. Differential inhibition by ferulic acid of nitrate and ammonium uptake in Zea mays L. Plant Physiology 98:639-645.

Blum, U., Gerig, T. M., Worsham, A. D., Holappa, L. D., and King, L. D. 1992. Allelopathic activity in wheat-conventional and wheat-no-till soils: Development of soil extract bioassays. J. Chem. Ecol. 18:2191-2221.

Booker, F. L., Blum, U., and Fiscus, E. L. 1992. Short-term effects of ferulic acid on ion uptake and water relations in cucumber seedlings. J. Expt. Bot. 43:649-655.

Blum, U., Gerig, T. M., Worsham, A. D., and King, L. D. 1993. Modification of allelopathic effects of p-coumaric acid on morning-glory seedling biomass by glucose, methionine, and nitrate. J. Chem. Ecol. 19:2791-2811.

Gerig, T. M., and Blum, U. 1993. Modification of an inhibition curve to account for effects of a second compound. J. Chem. Ecol. 19:2783-2790.

Blum, U., Worsham, A. D., King, L. D. and Gerig, T. M. 1994. Use of water and EDTA extractions to estimate available (free and reversibly bound) phenolic acids in Cecil soils. J. Chem. Ecol. 20:341-359.

Lehman, M. E., Blum, U., and Gerig, T. M. 1994. Simultaneous effects of ferulic and p-coumaric acids on cucumber leaf expansion in split-root experiments. J. Chem. Ecol. 20:1773-1782.

Pue, K. J., Blum, U., Gerig, T. M., and Shafer, S. R. 1995. Mechanism by which non inhibitory concentrations of glucose increase inhibitory activity of p-coumaric acid on morning-glory seedling biomass accumulation. J. Chem. Ecol. 21:833-847.

Blum, U. 1996. Allelopathic interactions involving phenolic acids. J. Nematology 28:259-267.

Blum, U. 1997. The benefits of citrate over EDTA for extracting phenolic acids from soils and plant debris. J. Chem. Ecol. 23:347-362.

Blum, U., King, L. D., Gerig, T. M., Lehman, M. E., and Worsham A. D. 1997. Effects of clover and small grain cover crops and tillage techniques on seedling emergence of some dicotyledonous weed species. Amer. J. Alternative Agriculture. 12:146-161.

Lehman, M. E. and Blum, U. 1997. Cover crop debris effects on weed emergence as modified by environmental factors. Allelopathy J. 4:69-88.

Blum, U. 1998. Effects of microbial utilization of phenolic acids and their phenolic acid breakdown products on allelopathic interactions. J. Chem. Ecol. 24:685-708.

Shafer, S. R., Blum, U., Horton, S. J., and Hesterberg, D. L., 1998. Biomass of tomato seedlings exposed to an allelopathic phenolic acid and enriched atmospheric carbon dioxide. Water, Air, and Soil Pollution. 106:123-136.

Blum, U., Shafer, S. R., and Lehman, M. E. 1999. Evidence for inhibitory allelopathic interactions involving phenolic acids in field soils: Concepts vs. an experimental model. Critical Reviews in Plant Sciences 18:673-693.

Lehman, M. E. and Blum, U. 1999. Influence of pretreatment stresses on inhibitory effects of ferulic acid, an allelopathic phenolic acid. J. Chem. Ecol. 25:1517-1529.

Lehman, M. E. and Blum, U. 1999. Evaluation of ferulic acid uptake as a measurement of allelochemical dose: Effective concentration. J. Chem. Ecol. 25:2585-2600.

Blum, U., Staman, K. L., Flint, L. J. and Shafer, S. R. 2000. Induction and/or selection of phenolic acid-utilizing bulk-soil and rhizosphere bacteria and their influence on phenolic acid phytotoxicity. J. Chem. Ecol. 26:2059-2078.

Staman, K., Blum, U., Louws, F., and Robertson, D. 2001. Can simultaneous inhibition of seedling growth and stimulation of rhizosphere bacterial populations provide evidence for phytotoxin transfer from plant residues in the bulk soil to the rhizosphere of sensitive species? J. Chem. Ecol. 27:807-829.

Blum, U. King, L. D. and Brownie, C. 2002. Effects of wheat residues on dicotyledonous weed emergence in a simulated no-till system. Allelopathy J. 9:159-176.

Wright, A. N., Warren, S. L., Blazich, F. A. and Blum U. 2004. Root and shoot growth periodicity of Kalmia latifolia 'Sarah' and Ilex crenata 'Compacta'. HortScience 39:243-247.

Blum, U. and Gerig, T. M. 2005. Relationships between phenolic acid concentrations, transpiration, water utilization, leaf area expansion, and uptake of phenolic acids: Nutrient culture studies. J. Chem. Ecol. 31:1907-1932.

Blum, U. and Gerig, T. M. 2006. Interrelationships between p-coumaric acid, evapotranspiration, soil water content, and leaf expansion. J. Chem. Ecol. 32:1817-1834.

Book Chapters
Heck, W. W., Blum, U. Reinert, R. A. and Heagle, A. S. 1982. Effects of air pollution on crop production. In: Strategies of Plant Reproduction (BARC Symposium No. 6 -Werner J. Meudt, Ed.) Allanheld, Osmun, and Co. Pub. Inc., London. Pages 333-350.

Heck, W. W., Blum, U., Boss, W. F., Heagle, A. S., Linthurst, R. A. Reinert, R. A., Reynolds J. F. and Rogers, H. 1984. Perspectives of air pollution research on plants. In: Reviews In Environmental Toxicology I. (E. Hodgson, Ed.) Elsevier Science Publishers, Amsterdam. Pages 173-249.

Blum, U. 1986. Plants defend themselves chemically. In: Research for Tomorrow - 1986 Yearbook of Agriculture. (J. J. Crowley Ed.) USDA, Beltsville. Pages 139-142.

Blum, U. 1995. The value of model plant-microbe-soil systems for understanding processes associated with allelopathic interactions. In: Allelopathy: Organisms, Processes, and Applications. (Inderjit, K.M.M. Daskshini and F. A. Einhellig Eds.) ACS Symposium Series No. 582. American Chemical Society, Washington DC. Pages 127-131.

Blum, U. 1999. Designing laboratory plant debris-soil bioassays: Some reflections. In: Principles and Practices in Plant Ecology: Allelochemical Interactions. (Inderjit, K.M.M. Daskshini and C. L. Foy Eds.) CRC Press, Boca Raton. Pages 17-23.

Blum, U., Austin, M. F. and Shafer, S. R. 1999. The fates and effects of phenolic acids in a plant-microbe-soil model system. In Recent Advances in Allelopathy I. A Science for the Future. (F. A. Macias, J. G. C. Galindo, J. M. G. Molinillo, and H. Cutler Eds.) Cadiz University Press, Puerto Real. Pages 159-166.

Blum, U. 2001. Allelopathy. In Encyclopedia of Plant Pathology. (O. C. Maloy and T. D. Murray, Eds.) John Wiley and Sons, Inc., New York. Pages 33-34.

Blum, U. 2004. Fate of phenolic allelochemicals in soils: The role of soil and rhizosphere microorganisms. In: Allelopathy: Chemistry & Modes of Action of Allelochemicals. (F. A. Macias, J. G. C. Galindo, J. M. G. Molinillo, and H. Cutler Eds). CRC Press, Boca Raton. Pages 57 -76.

Blum, U. 2006. Allelopathy: A soil system perspective. In Allelopathy. A Physiological Process with Ecological Implications. (M. J. Reigosa, N. Pedrol, and L. Gonzalez EDS). Springer, Dordrecht, The Netherlands. Pages 299-340.

Blum, U. 2007. Can data derived from field and laboratory bioassays establish the existence of allelopathic interactions in nature?  In: Allelopathy: New Concepts and Methodology. (Y. Fujii and S. Hiradate, Eds.) Science Publishers, New Hampshire. Pages 31-38.

Books
Blum, U. 2011. Plant-plant allelopathic interactions. Phenolic acids, cover crops and weed emergence. Springer Science Business Media, Dordrecht. 200 pages.

Blum, U. 2014. Plant-plant allelopathic interactions II. Laboratory bioassays for water-soluble compounds with an emphasis on phenolic acids. Springer Science Business Media, Cham. 322 pages.


Teaching Publications
Blum, U. (with contributions by N. Allen and D. Robertson) 1998. Laboratory Manual. Plant Biology BO 295. Plant Biology, NCSU. 58 pages

Blum, U. (with contributions by N. Allen, D. Robertson, K. Shank, K. Staman, and S. Wyatt) 1999. Laboratory Manual. Plant Biology BO 250 L. Ed. 2. Plant Biology, NCSU. 52 pages

Blum, U. (with contribution by N. Allen) 2000. Laboratory Manual. Plant Biology BO 250 L. Ed. 3. Plant Biology, NCSU. 57 pages.

Blum, U. 2000. Lecture Course Pack. Plant Biology BO 250. Plant Biology, NCSU. 92 pages.

Blum, U. (with contributions by N. Allen and D. Robertson) 2001. Laboratory Manual. Plant Biology BO 250 L. Ed. 4. Plant Biology, NCSU. 60 pages.

Blum, U. 2001. Lecture Course Pack. Plant Biology BO 250. Ed. 2. 100 pages.

Other Publications and Reports
Seneca, E. D., L. M. Stroud, U. Blum and G. R. Noggle. 1974. An analysis of the effects of the Brunswick Nuclear Power Plant on the productivity of Spartina alterniflora (smooth cordgrass) in Oak Island, Dutchman Creek and Walden Creek, Snow's Marshes, Brunswick County, NC. 1973-1974. First Annual Report, April, 1974. pp. 1 to 68.

Seneca, E. D., L. M. Stroud, U. Blum and G. R. Noggle. 1975. An analysis of the effects of the Brunswick Nuclear Power Plant on the productivity of Spartina alterniflora (smooth cordgrass) in the Dutchman Creek, Oak Island, Snow's Marsh, and Walden Creek Marshes, Brunswick County, NC. 1974-1975. Second Annual Report, April, 1975. pp. 1-137.

Seneca, E. D., L. M. Stroud, U. Blum and G. R. Noggle. 1976. An analysis of the effects of the Brunswick Nuclear Power Plant on the productivity of Spartina alterniflora (smooth cordgrass) in the Dutchman Creek, Oak Island, Snow's Marsh, and Walden Creek Marshes, Brunswick County, NC. 1975-1976. Third Annual Report, September, 1976. pp. 1-335.

Seneca, E. D., L. M. Stroud and U. Blum. 1977. An analysis of the effects of the Brunswick Nuclear Power Plant on the productivity of Spartina alterniflora (smooth cordgrass) in the Dutchman Creek, Oak Island, Snow's Marsh, and Walden Creek Marshes, Brunswick County, NC. 1976-1977. Fourth Annual Report, December, 1977. pp. 1-80.

Seneca, E. D., L. M. Stroud and U. Blum. 1979. An analysis of the effects of the Brunswick Nuclear Power Plant on the productivity of Spartina alterniflora (smooth cordgrass) in the Dutchman Creek, Oak Island, Snow's Marsh, and Walden Creek Marshes, Brunswick County, NC. 1977-1978. Fifth Annual Report, January 1979. pp. 1-223.


Cammen, L. M., U. Blum, E. D. Seneca and L. M. Stroud. 1980. Preliminary energy budget for a salt marsh. In the Cape Fear Rivery Estuary, NC UNC Sea Grant College Publication UNC-SG-WP-80-3. pp. 1-35.

Seneca, E. D., R. A. Linthurst, L. M. Stroud and U. Blum. 1980. An analysis of the effects of the Brunswick Nuclear Power Plant on the productivity of Spartina alterniflora (smooth cordgrass) in the Dutchman Creek, Oak Island, Snow's Marsh, and Walden Creek Marshes. Sixth and Final Report, February 1980. pp. 1-354.