An overview of microfibril angle in fiber of tension wood
نویسندگان
چکیده
The angle between helical windings of microfibrils in the secondary cell wall of fibers and the long axis is called microfibril angle (MFA). Stiffness of wood depends on variations in the MFA. The large MFA shows low stiffness, which is found in juvenile wood and this character make threes vulnerable to high winds breaking. Timber containing a high proportion of juvenile wood is unsuitable for use as high-grade structural timber. On the other hand, the small MFA in wood shows high stiffness, which has importance in a good view of the trend in forestry. The timber with high stiffness is commonly high economic value. They are grown mainly for construction, timber and furniture. Until date, it is under pressure for increased timber production means that ways will be sought to improve the quality of timber by reducing MFA. Commonly, MFA decrease during the formation of tension wood therefore study on tension wood related to MFA formation is important for MFA reduction in normal wood. The study on tension wood formation could predict expression patterns of genes/proteins for reduction of MFA. Herein, the orientation of microfibril and MFA in cell wall layers of normal and tension wood fiber are discussed.
منابع مشابه
Chemical responses to modified lignin composition in tension wood of hybrid poplar (Populus tremula x Populus alba).
The effect of altering the expression level of the F5H gene was investigated in three wood tissues (normal, opposite and tension wood) in 1-year-old hybrid poplar clone 717 (Populus tremula × Populus alba L.), containing the F5H gene under the control of the C4H promoter. Elevated expression of the F5H gene in poplar has been previously reported to increase the percent syringyl content of ligni...
متن کاملThe origin of maturation stress in tension wood: using a micro- mechanical model to discriminate between hypothetic mechanism
Tension wood generates axial tensile stress and tangential compressive stress during its formation, but the mechanism causing this stress is not yet fully understood. A micro-mechanical model is used to test different hypothetic mechanism, based on the assumption that one of the constituents of tension wood undergoes a dimensional change during the formation of the wall. The consistency between...
متن کاملVariation of microfibril angle of Pinus... VARIATION OF MICROFIBRIL ANGLE OF Pinus radiata D. Don IN RELATION TO TREE SPACING IN CHILEAN PLANTATIONS1
Four stands of 28-year-old radiata pine (Pinus radiata D. Don) grown in the eighth region (Biobio) of Chile were sampled to determine the effect of tree spacing on the microfibril angle. The samples were taken at two different stem levels of the tree, 2.5 m and 7.5 m, with increment strip taken in the Nothern direction. The four experimental stands were characterized by the following spacing 2x...
متن کاملTension wood structure and morphology conducive for better enzymatic digestion
Background Tension wood is a type of reaction wood in response to bending or leaning stem as a corrective growth process. Tension wood is formed by both natural and man-made processes. Most attractively, tension wood contains higher glucan content and undergoes higher enzymatic conversion to fermentable sugars. Here, we have employed structural techniques, small-angle neutron scattering (SANS) ...
متن کاملMaturation stress generation in poplar tension wood studied by synchrotron radiation microdiffraction.
Tension wood is widespread in the organs of woody plants. During its formation, it generates a large tensile mechanical stress, called maturation stress. Maturation stress performs essential biomechanical functions such as optimizing the mechanical resistance of the stem, performing adaptive movements, and ensuring long-term stability of growing plants. Although various hypotheses have recently...
متن کامل