To assess the characteristics of tension wood (TW) in Trochodendron aralioides Sieb. et Zucc., seedling stems were artificially inclined at angles of 30° (TW- 30), 50° (TW-50), and 70° (TW-70) from the vertical. At all angles, the growth promotion was pronounced on the upper side of the inclined stems, where excessive tensile growth stress was observed. A gelatinous layer (G-layer) formed in the tracheids of TW. The cell wall structure of the tracheids in TW was S1 + G. The G-layer had a small pit aperture angle <10°. TW-50 showed larger tensile growth stress, a thicker G-layer area, and a smaller pit aperture angle of the Glayer than TW-30 and TW-70. Lower levels of Klason lignin and hemicellulose and higher levels of α-cellulose content were observed in TW-50. In addition, an increase in glucose content and a decrease in xylose content in holocellulose were observed in TW-50. Therefore, it can be concluded that the degree of TW varied with different inclination angles.
Rapeseed (Brassica napus L.) stalks are widely available. Data on their fiber morphology and chemical composition is important to establish their best performance during pulping. This study found that average fiber length, fiber width, cell wall thickness, and lumen width of rapeseed were 1.32 mm, 31 μm, 5.75 μm, and 19.5 μm, respectively. Rapeseed fibers appear almost identical to wood fibers, but the accompanying vessel elements and parenchyma cells mean that small particles (fines) will be produced during refining. The chemical analysis of depithed rapeseed stalks showed that the cellulose, lignin, holocellulose, pentosan, and ash were 48.5%, 20%, 77.5%, 17%, and 6.6%, respectively. Alcoholacetone, hot water, cold water, and 1%-NaOH solubility were 6.6%, 5%, 13.8%, and 50.3%, respectively. These results indicate rapeseed stalks are suitable for pulping and papermaking.
In this paper we investigate the influence of extractives, lignin and holocellulose contents on performance index (PI) of seven woods used or tested for violin bows. Woods with higher values of this index (PI = √MOE/ρ, where MOE is modulus of elasticity and ρ is density) have a higher bending stiffness at a given mass, which can be related to bow wood quality. Extractive content was negatively correlated with PI in Caesalpinia echinata, Handroanthus sp. and Astronium lecointei. In C. echinata holocellulose was positively correlated with PI. These results need to be further explored with more samples and by testing additional wood properties. Although the chemical constituents could provide an indication of quality, it is not possible to establish appropriate woods for bows solely by examining their chemical constituents.
Structural heartwood characteristics for Prosopis laevigata (Humb. & Bonpl. ex Willd.) M.C. Johnst., including a histometrical evaluation, were obtained by light microscopy coupled with a digitised image analysis system. The growth ring boundaries of the semi-ring-porous or diffuseporous wood are often marked by a marginal parenchyma band. Average fibre length is 975 μm, the fibres are thick-walled with a single cell wall thickness of 13 μm on average. Average diameter of the vessels which are arranged in non-specific patterns differs significantly between earlywood (116 μm) and latewood (44 μm). The topochemical distribution of lignin and phenolic deposits in the tissue was investigated by means of scanning UV microspectrophotometry (UMSP). Thereby, in heartwood tissue the deposition of extractives in vessels, pit canals, parenchyma cells, fibre lumina and partly also in the S2 layers of the fibres was detected. Monosaccharides were qualitatively and quantitatively determined by borate complex anion exchange chromatography. Holocellulose content is between 61.5 and 64.7% and Klason lignin content between 29.8 and 31.4%. Subsequent extraction of the soluble compounds was performed with petrolether, acetone/water and methanol/water by accelerated solvent extraction (ASE). Total extractives content in heartwood ranges between 14 to 16% on a dry weight basis. Major compounds in acetone/water extracts were identified as (-)-epicatechin, (+)-catechin and taxifolin, and quantitatively determined by liquid chromatography (RP-HPLC-UV).
. 2012 . Relationship among extractives, lignin and holocellulose contents with performance index of seven species used for bows of string instruments . IAWA J. 33 : 141 – 149 . DOI: 10.1163/22941932-90000085 .
Longui EL , de Lima IL , Lombardi DR , Garcia JN , Alves ES . 2014
fracture, the S1 layer often forming a zone of weakness ( Donaldson 1995 ). Figure 3 Cross section of pine holocellulose showing the cellulose microfibrils in the primary (p) and secondary (S1, S2, S3) cell wall of a tracheid. − Scale bar = 1 μm. The molecular structure of cellulose microfibrils is
. 2003 . Determination of surface area and pore volume of holocellulose and chemically modified wood flour using the nitrogen adsorption technique . Holz Roh Werkst . 61 : 453 – 456 . doi.org/ 10.1007/s00107-003-0430-5 .