Longitudinal mechanical properties of cell wall of Masson pine (Pinus massoniana Lamb) as related to moisture content: A nanoindentation study

Holzforschung ◽  
2011 ◽  
Vol 65 (1) ◽  
pp. 121-126 ◽  
Author(s):  
Yan Yu ◽  
Benhua Fei ◽  
Hankun Wang ◽  
Genlin Tian

Abstract The in situ imaging nanoindentation technique was used to investigate how the moisture content (MC) affects the longitudinal mechanical properties of Masson pine cell wall. Furthermore, nanoindentation tests in liquid water were performed. The results indicate that elastic modulus, hardness, and compression yield stress of wood wall are all linearly correlated to the selected MC region in the range from 4.5% to 13.1%. Remarkable differences were found between the experimental values measured in water and the extrapolated values based on regression equations below fiber saturation point.

Forests ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 646 ◽  
Author(s):  
Wang ◽  
Chen ◽  
Xie ◽  
Cai ◽  
Yuan ◽  
...  

The local chemistry and mechanics of the control and phenol formaldehyde (PF) resin modified wood cell walls were analyzed to illustrate the modification mechanism of wood. Masson pine (Pinus massoniana Lamb.) is most widely distributed in the subtropical regions of China. However, the dimensional instability and low strength of the wood limits its use. Thus, the wood was modified by PF resin at concentrations of 15%, 20%, 25%, and 30%, respectively. The density, surface morphology, chemical structure, cell wall mechanics, shrinking and swelling properties, and macro-mechanical properties of Masson pine wood were analyzed to evaluate the modification effectiveness. The morphology and Raman spectra changes indicated that PF resin not only filled in the cell lumens, but also penetrated into cell walls and interacted with cell wall polymers. The filling and diffusing of resin in wood resulted in improved dimensional stability, such as lower swelling and shrinking coefficients, an increase in the elastic modulus (Er) and hardness (H) of wood cell walls, the hardness of the transverse section and compressive strength of the wood. Both the dimensional stability and mechanical properties improved as the PF concentration increased to 20%; that is, a PF concentration of 20% may be preferred to modify Masson pine wood.


Forests ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1247
Author(s):  
Yan Wu ◽  
Xinyu Wu ◽  
Feng Yang ◽  
Haiqiao Zhang ◽  
Xinhao Feng ◽  
...  

Masson pine (Pinus massoniana Lamb.) samples were heat-treated at different treatment temperatures (150, 170, and 190 °C), and the nano-mechanical properties of the wood cell wall, which was coated with a waterborne polyacrylic (WPA) lacquer product, were compared. The elastic modulus (Er) and hardness (H) of wood cell wall and the coating were measured and characterized by nanoindentation, and the influencing factors of mechanical properties during thermal modification were investigated by chemical composition analysis, contact angle analysis, and colorimetric analysis. The results showed that with the increase in the heat treatment temperature, the contact angle of the water on the wood’s surface and the colorimetric difference increased, while the content of the cellulose and hemicelluloses decreased. After thermal modification of 190 °C, the Er and H of the wood cell wall increased by 13.9% and 17.6%, respectively, and the Er and H of the WPA coating applied to the wood decreased by 12.1% and 22.2%. The Er and H of the interface between the coating and wood were lower than those near the coating’s surface. The Er and H of the cell wall at the interface between the coating and wood were lower than those far away from the coating. This study was of great significance for understanding the binding mechanism between coating and wood cell walls and improving the finishing technology of the wood materials after thermal modification.


2020 ◽  
Vol 477 ◽  
pp. 118503
Author(s):  
Cheng Deng ◽  
Shougong Zhang ◽  
Yuanchang Lu ◽  
Robert E. Froese ◽  
Xiaojun Xu ◽  
...  

2012 ◽  
Vol 506 ◽  
pp. 607-610 ◽  
Author(s):  
N. Thongjun ◽  
Lerpong Jarupan ◽  
Chiravoot Pechyen

Oil palm frond pulp (OPF) was blended with activated carbon for the purpose of active packaging in this preliminary study. It was aimed to investigate the effect of in-situ activated carbon on physical and mechanical properties of the pulp handsheets made from OPF. Testing of property performances of the resulted handsheets included density, moisture content, thickness swelling, folding, tensile strength, %elongation, stiffness, and modulus of rupture. Ultimately, the intention is to use for prospected active packaging for fresh produce. OPF pulp was prepared by the kraft process. The pulp stock was mixed with different proportions of activated carbon (0, 10, 20, and 30% w/w). The results showed that an increased proportion of activated carbon decreased density and thickness selling, but had no effect on moisture content.


Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1618
Author(s):  
Sheng Yao ◽  
Peizhen Chen ◽  
Ye Yu ◽  
Mengyang Zhang ◽  
Dengbao Wang ◽  
...  

Wood formation originates in the biosynthesis of lignin and further leads to secondary cell wall (SCW) biosynthesis in woody plants. Masson pine (Pinus massoniana Lamb) is an economically important industrial timber tree, and its wood yield affects the stable development of the paper industry. However, the regulatory mechanisms of SCW formation in Masson pine are still unclear. In this study, we characterized PmMYB4, which is a Pinus massoniana MYB gene involved in SCW biosynthesis. The open reading frame (ORF) of PmMYB4 was 1473 bp, which encoded a 490 aa protein and contained two distinctive R2 and R3 MYB domains. It was shown to be a transcription factor, with the highest expression in semi-lignified stems. We overexpressed PmMYB4 in tobacco. The results indicated that PmMYB4 overexpression increased lignin deposition, SCW thickness, and the expression of genes involved in SCW formation. Further analysis indicated that PmMYB4 bound to AC-box motifs and might directly activate the promoters of genes (PmPAL and PmCCoAOMT) involved in SCW biosynthesis. In addition, PmMYB4-OE(over expression) transgenic lines had higher lignin and cellulose contents and gene expression than control plants, indicating that PmMYB4 regulates SCW mainly by targeting lignin biosynthetic genes. In summary, this study illustrated the MYB-induced SCW mechanism in Masson pine and will facilitate enhanced lignin and cellulose synthesis in genetically engineered trees.


2020 ◽  
Vol 21 (20) ◽  
pp. 7548
Author(s):  
Qifei Ren ◽  
Yunchao Zhou ◽  
Xinwei Zhou

Nitrogen (N) is an essential nutrient for plant growth and development. Plant species respond to N fluctuations and N sources, i.e., ammonium or nitrate, differently. Masson pine (Pinus massoniana Lamb.) is one of the pioneer plants in the southern forests of China. It shows better growth when grown in medium containing ammonium as compared to nitrate. In this study, we had grown masson pine seedlings in medium containing ammonium, nitrate, and a mixture of both, and performed comparative transcriptome and proteome analyses to observe the differential signatures. Our transcriptome and proteome resulted in the identification of 1593 and 71 differentially expressed genes and proteins, respectively. Overall, the masson pine roots had better performance when fed with a mixture of ammonium and nitrate. The transcriptomic and proteomics results combined with the root morphological responses suggest that when ammonium is supplied as a sole N-source to masson pine seedlings, the expression of ammonium transporters and other non-specific NH4+-channels increased, resulting in higher NH4+ concentrations. This stimulates lateral roots branching as evidenced from increased number of root tips. We discussed the root performance in association with ethylene responsive transcription factors, WRKYs, and MADS-box transcription factors. The differential analysis data suggest that the adaptability of roots to ammonium is possibly through the promotion of TCA cycle, owing to the higher expression of malate synthase and malate dehydrogenase. Masson pine seedlings managed the increased NH4+ influx by rerouting N resources to asparagine production. Additionally, flavonoid biosynthesis and flavone and flavonol biosynthesis pathways were differentially regulated in response to increased ammonium influx. Finally, changes in the glutathione s-transferase genes suggested the role of glutathione cycle in scavenging the possible stress induced by excess NH4+. These results demonstrate that masson pine shows increased growth when grown under ammonium by increased N assimilation. Furthermore, it can tolerate high NH4+ content by involving asparagine biosynthesis and glutathione cycle.


Holzforschung ◽  
2017 ◽  
Vol 71 (6) ◽  
pp. 491-497 ◽  
Author(s):  
Hankun Wang ◽  
Zixuan Yu ◽  
Xuexia Zhang ◽  
Dan Ren ◽  
Yan Yu

Abstract The combined effects of initial microfibril angle (MFA) and moisture content (MC) on the longitudinal tensile properties of Masson pine (Pinus massoniana Lamb.) wood foils has been investigated. Synchrotron X-ray diffraction (XRDsyn) combined with a custom-built microtensile device was applied for in situ monitoring of the MFA alterations in the foils under different initial MFAs and MCs conditions. The results demonstrate that the tensile properties are highly negatively correlated to both MFA and MC. Furthermore, the tensile modulus is more sensitive to MC change than tensile strength. At a higher MFA, the sensitivity of the two mechanical indicators to MC alteration is enhanced.


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