Significant influence of lignin on axial elastic modulus of poplar wood at low microfibril angles under wet conditions

Autor(es)

Ozparpucu, Merve ^{[1, 2]} ; Gierlinger, Notburga ^[3] ; Cesarino, Igor ^[4] ; Burgert, Ingo ^{[1, 5]} ; Boerjan, Wout ^{[6, 7]} ; Ruggeberg, Markus ^{[1, 5]}

Afiliação do(s) autor(es)

^[1] Swiss Fed Inst Technol, Inst Bldg Mat IfB, CH-8093 Zurich - Switzerland

^[2] TUM, Wood Res Munich, Sch Life Sci Weihenstephan, D-80797 Munich - Germany

^[3] Univ Nat Resources & Life Sci Vienna BOKU, Inst Biophys, A-1190 Vienna - Austria

^[4] Univ Sao Paulo, Inst Biosci, Dept Bot, Sao Paulo, SP - Brazil

^[5] Empa, Lab Cellulose & Wood Mat, CH-8600 Dubendorf - Switzerland

^[6] Univ Ghent, Dept Plant Biotechnol & Bioinformat, B-9052 Ghent - Belgium

^[7] VIB Ctr Plant Syst Biol, B-9052 Ghent - Belgium

• Tipo de documento: Artigo Científico
• Fonte: Journal of Experimental Botany; v. 70, n. 15, p. 4039-4047, AUG 1 2019.
• Citações Web of Science: 1

Resumo

Wood is extensively used as a construction material. Despite increasing knowledge of its mechanical properties, the contribution of the cell-wall matrix polymers to wood mechanics is still not well understood. Previous studies have shown that axial stiffness correlates with lignin content only for cellulose microfibril angles larger than around 20 degrees, while no influence is found for smaller angles. Here, by analysing the wood of poplar with reduced lignin content due to down-regulation of CAFFEOYL SHIKIMATE ESTERASE, we show that lignin content also influences axial stiffness at smaller angles. Micro-tensile tests of the xylem revealed that axial stiffness was strongly reduced in the low-lignin transgenic lines. Strikingly, microfibril angles were around 15 degrees for both wild-type and transgenic poplars, suggesting that cellulose orientation is not responsible for the observed changes in mechanical behavior. Multiple linear regression analysis showed that the decrease in stiffness was almost completely related to the variation in both density and lignin content. We suggest that the influence of lignin content on axial stiffness may gradually increase as a function of the microfibril angle. Our results may help in building up comprehensive models of the cell wall that can unravel the individual roles of the matrix polymers. (AU)

• Processo FAPESP: 15/02527-1 - Desenvolvimento de sistemas-modelo em sorgo e uso da biologia de sistemas na elucidação dos mecanismos moleculares do metabolismo fenólico e de lignina em gramíneas
• Beneficiário: Igor Cesarino
• Modalidade de apoio: Auxílio à Pesquisa - Programa BIOEN - Jovens Pesquisadores