Identification of the cell wall synthesis genes in Betula Pendula

This study aims to provide information on Betula pendula cell wall synthesis genes regarding their potential physiological roles and the molecular mechanism associated. Here we identified 46 gene models in 7 gene families that encode cellulose synthase and related enzymes of B. pendula, and the transcript abundance of these genes in xylem, root, leaf, and flower tissues also be determined. Based on these RNA-seq data, we have identified 8 genes that most likely participate in cell wall synthesis, which include 3 cellulose synthase genes and 5 cellulose synthase-like genes. In parallel, a gene co-expression network was also constructed based on transcriptome sequencing. These analyses will help decipher the genetic information of B. pendula cell wall synthesis genes and alter its wood structure on the cellular level.

Structural and mechanical properties of cork cell walls from quercus variabilis blume (Fagaceae)

The properties of cork are strongly dependent on its cell wall properties. Thus, it is very important to characterize the cork cell walls in order to understand structure-property relationships. The reproduction cork tissue from Quercus variabilis Blume was examined with field-emission scanning electron microscopy to detect the structural characteristics of the cell walls. Several noteworthy anatomical features were present in the cells of Quercus variabilis cork. In most instances, the inner wall of cork cells was not smooth and showed an irregular surface. Solid deposits of various shapes were observed in the inner surfaces of the cell walls. Cell walls of cork tissue had severe corrugations in transverse and radial sections. Trabeculae were found for the first time in the cork tissue of Quercus variabilis Blume. They extended across a few cells, with a rod-like form. Nanoindentation techniques provide a new view of the mechanical properties of the cork cell walls. The hardness of cell walls of untreated and boiled reproduction cork from Quercus variabilis was 0.54 GPa and 0.51 GPa. The elastic modulus was 11.47 GPa and 11.81 GPa, respectively. Boiling treatment of cork could improve mechanical properties of cell walls.

Correlation between the stem hydraulic conductivity rates in scots pine (Pinus sylvestris L.) and the lignin content in tracheid walls

This paper is an attempt to evaluate the lignin formation in tracheid walls within the stem circumferential area in mature Scots pine (Pinus sylvestris L.), and establish the correlation between lignin content, and diameter at breast height and hydraulic conductivity in mature pine. The independent variables included lignin content (Lc) in tracheid walls within the stem circumferential area, and pine diameter at breast height (DBH), and the dependent variable was the relative conducting surface of stems (Sa/Nmass, Eas/Nmass). Research material came from the 89-91 year old pine stand in the north of Poland. Chemical analysis included mature wood area, i.e. last ten annual rings at 1.30 m (DBH). The results show clear interdependence between the relative conductive surface (stem hydraulic conductivity), and tree diameter at breast height and lignin content in tracheid walls within the stem circumferential area. Biometric features of pines grown in fresh coniferous forest (FC) and in fresh mixed coniferous forest (FMC) conditions were functionally linked. The link between these values was clear, although it varied, and could be approximated using the linear function.

Chemical characteristics of Eucalyptus pellita with heart rot

Eucalyptus pellita has been posited as a primary raw material in Indonesia due to its fast growth. In some areas, however, trees with heart rot were found. Thus, the wood with heart rot was analysed chemically both in sound (sapwood, outer heartwood, inner heartwood) and degraded parts (heart rot-affected wood/HRAW). The results revealed that there was a different trend in the wood chemical composition between bottom and centre parts. In bottom parts, wood with bigger diameter of heart rot, the slight changes in polysaccharides and lignin amounts was observed in HRAW compared to sound wood parts. On the contrary, comparatively high lignin and low polysaccharide levels in HRAW were measured in centre parts. HRAW was also characterized with high content of inorganic materials and high pH values but low in extractive content, mostly ethanol soluble extractives or its polar fraction. Increasing of phenolic contents was more pronounced in HRAW of lower part than that of upper of the stem. The difference trend of chemical composition between bottom and centre parts suggesting the cause of heart rot could be several wood degraders.

Nanomechanical behavior of wood cell walls observed by different indentation loading prerequisites

The variations of nanomechanical behavior of wood cell walls under different peak loads, loading times, and holding times were studied. Samples were separately loaded to preset peak loads of 100, 150, 200, 250 and 300 μN. Changes in the micromechanical properties were tracked in the longitudinal direction to determine change values of the elastic modulus and hardness. Moreover, the creep behavior was also analyzed under different holding times. It was found that the longer the holding time, the larger the creep ratio of all of the samples, and the creep rate decreased slowly with longer loading times. Finally, when the peak load was larger, the displacement rate and strain rate increased, but the strain rate in each test exhibited a tendency to become constant after 10 s.