Mechanical Properties of Genetically Engineered Young Aspen with Modified Lignin Content and/or Structure
Keywords:Alpha-cellulose, aspen, compression strength, lignin, mechanical properties, modulus of elasticity, <i>Populus tremuloides</i>, transgenic tree
AbstractReducing lignin content is a target for processes such as papermaking because lignin removal requires a tremendous amount of energy and chemicals. Recent advances in tree genetics permit modification of lignin content and structure. The consequences of lignin modifications on many wood properties are not known. The purpose of this study was to establish the effect of genetic modification of lignin on selected wood mechanical properties. In this study, genetically modified young quaking aspen trees with reduced lignin content and/or increased syringyl to guaiacyl (S/G) ratio were investigated and compared with the wild type. The modulus of elasticity in three-point bending and the compression strength parallel to the grain were measured using modified micromechanical tests. The results indicate that the genetic modification used in this study had a negative effect on these mechanical properties. The transgenic trees with reduced lignin content showed a severe reduction in modulus of elasticity and compression strength parallel to the grain, whereas the transgenic trees with increased S/G ratio had only a slight decrease in these properties compared with the wild type. The simultaneous modification of lignin content and S/G ratio shows inconsistent results and needs further investigation.
Baucher M, Halpin C, Petit-Conil M, Boerjan W. (2003) Lignin: Genetic engineering and impact on pulping. Crit Rev Biochem Mol 38:305-350.nBendtsen BA, Senft J. (1986) Mechanical and anatomical properties in individual growth rings of plantation-grown eastern cottonwood and loblolly pine. Wood Fiber Sci 18(1):23-38.nBjurhager I, Berglund LA, Bardage SL. (2008) Mechanical characterization of juvenile European aspen (Populus tremula) and hybrid aspen (Populus tremula x Populus tremuloides) using full-field strain measurements. J Wood Sci 54:349-355.nChen C, Baucher M, Christensen JH, Boerjan W. (2001) Biotechnology in trees: Towards improved paper pulping by lignin engineering. Euphytica 118:185-195.nChiang VL. (2002) From rags to riches. Nat Biotechnol 20:557-558.nCoutand C, Jeronimidis G, Chanson B, Loup C. (2004) Comparison of mechanical properties of tension and opposite wood in Populus. Wood Sci Technol 38:11-24.nFladung M. (1999) Gene stability in transgenic aspen (Populus). I. Flanking DNA sequences and T-DNA structure. Mol Gen Genet 260:574-581.nFladung M, Kumar S. (2002) Gene stability in transgenic aspen (Populus). III. T-DNA repeats influence transgene expression differentially among different transgenic lines. Plant Biol 4:329-338.nFPL (1999) Wood handbook—Wood as an engineering material. General Technical Report FPL-GTR-113. USDA For Serv Forest Products Laboratory, Madison, WI. 463 pp.nGindl W. (2001) The effect of lignin on the moisture-dependent behavior of spruce wood in axial compression. J Mater Sci Lett 20:2161-2162.nGindl W, Teischinger A. (2002) Axial compression strength of Norway spruce related to structural variability and lignin content. Compos Part A-Appl S 33:1623-1628.nHernandez R, Koubaa A, Beaudoin M, Fortin Y. (1998) Selected mechanical properties of fast-growing poplar hybrid clones. Wood Fiber Sci 30(2):138-147.nHorvath B. (2009) Effect of lignin content and structure on the anatomical, physical and mechanical properties of genetically engineered aspen trees. Doctoral Dissertation, North Carolina State University, Raleigh, NC. 193 pp.nJames RR, DiFazio SP, Brunner AM, Strauss SH. (1998) Environmental effects of genetically engineered woody biomass crops. Biomass Bioenerg 14(4):403-414.nJones L, Ennos AR, Turner SR. (2001) Cloning and characterization of irregular xylem4 (irx4) a severely lignindeficient mutant of Arabidopsis. Plant J 26(2):205-216.nKasal B, Peszlen I, Peralta P, Li L. (2007) Preliminary test to evaluate the mechanical properties of young trees with small diameter. Holzforschung 61:390-393.nKoehler L, Telewski FW. (2006) Biomechanics of transgenic wood. Am J Bot 93(10):1433-1438.nKöhler L, Spatz H-C. (2002) Micromechanics of plant tissues beyond the linear-elastic range. Planta 215:33-40.nLee J. (1997) Biological conversion of lignocellulosic biomass to ethanol. J Biotechnol 56:1-24.nLi L, Zhou Y, Cheng X, Sun J, Marita JM, Ralph J, Chiang VL. (2003) Combinatorial modification of multiple lignin traits in trees through multigene cotransformation. Proc Natl Acad Sci USA 100(8):4939-4944.nMoerschbacher BM, Noll U, Gorrichon L, Reisener H-J. (1990) Specific inhibition of lignification breaks hypersensitive resistance of wheat to stem rust. Plant Physiol 93:465-470.nPeszlen I. (1998) Variation in specific gravity and mechanical properties of poplar clones. Drevársky výskum 43(2):1-17.nPilate G, Guiney E, Holt K, Petit-Conil M, Lapierre C, Laple J-C, Pollet B, Mila I, Webster EA, Marstrop HG, Hopkins DW, Jouanin L, Boerjan W, Schuch W, Cornu D, Halpin C. (2002) Field and pulping performances of transgenic tree with altered lignification. Nat Biotechnol 20:607-612.nSAS (2006) SAS Enterprise Guide 4.1. SAS Institute, Inc., Cary, NC.nSederoff RR, Chang H-M. (1991) Lignin biosynthesis. Pages 263-285 in M Lewin and ISGoldstein, eds. Wood structure and composition. International fiber science and technology series. M. Dekker, New York, NY.nTalukder K. (2006) Low-lignin wood—A case study. Nat Biotechnol 24(4):395-396.nTuskan GA, DiFazio SP, Teichmann T. (2003) Poplar genomics is getting popular: The impact of the poplar genome project on tree research. Plant Biol 5:1-3.nWardrop AB. (1971) Occurrence and formation in plants. Pages 19-41 in KV Sarkanen and CH Ludwig, eds. Lignins: Occurrence, formation, structure, and reactions. Wiley Interscience, New York, NY.nWhetten R, Sederoff R. (1991) Genetic engineering of wood. For Ecol Mgmt 43:301-316.nYeh T-F, Yamada T, Capanema E, Chang H-M, Chiang V, Kadla JF. (2005) Rapid screening of wood chemical component variations using transmittance near-infrared spectroscopy. J Agric Food Chem 53: 3328-3332.nYokoyama T, Kadla JF, Chang H-M. (2002) Microanalytical method for the characterization of fiber components and morphology of woody plants. J Agric Food Chem 50: 1040-1044.n
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