Biomechanics and transgenic wood

Abstract

Wood, or secondary xylem, is composed mostly of three components-cellulose, hemicelluloses, and lignin. Yet this apparent simplicity is deceiving because the sophisticated arrangement of the components on various structural levels, ranging from intricate molecular architecture to defined cellular arrangements to tissue morphology, makes wood a challenging and interesting subject of biomechanical investigation. Recent advances in genetic transformation, providing easier access to wood of specifically altered composition or structure, have opened new opportunities for research on the intricate relation between material structure and composition and mechanical properties. At the same time, investigations into the mechanical properties have provided new information regarding the structural configuration of wood. The present paper reviews the work conducted in this field and outlines future perspectives and prospects for research.

Raman Imaging of Lignocellulosic Feedstock

“…Since this time a focus on genetic engineering of lignin content and composition can be observed [37][38][39][40]. The effect of downregulation of lignin biosynthetic enzymes on wood anatomy [41] and its biomechanics [42] has been investigated [43]. In stems of transgenic alfalfa lines recalcitrance to both acid pre-treatment and enzymatic digestion was found to be directly proportional to lignin content [44].…”

Anatomy and lignification status of the Lophanthera lactescens Ducke plant grown in vitro

“…It is compatible with the molecular resistance hypothesis. Syringyl lignin in mutant plants demonstrated a more progressive increase of elastic module than guaiacyl lignin (Koehler and Telewski, 2006). The increase in cambial activity in the middle of the vascular cylinder and the occurrence of gelatinous fibers in the twisted stems of L. lactescens appeared to be a survival strategy in response to in vitro growth environment or hormone activity (Kwon, 2008).…”

Genetic Transformation of Forest Trees

“…Studies in populations of forest tree hybrids have shown a negative correlation of biomass growth and lignin content, implying that selection for improved growth rate could be accompanied by a reduction in lignin content (Novaes et al, 2010). However, it is clear from some of the above-mentioned experiences with transgenic trees, that a minimum amount of lignin is needed for anchoring the cellulose and hemicellulose components together for proper cell wall genesis and maintenance of structural integrity, and that a concentration below this tolerable limit would probably lead to cell wall disorganization and growth alterations (Koehler & Telewski, 2006).…”