Genetic variation of Norway spruce clones regarding their natural durability, physical and chemical properties

Abstract

Genetic variation of ten Norway spruce (<i>Picea abies</i> (L.) Karst.) clones regarding their decay resistance against brown rot fungi, as well as physical and chemical properties of clones were investigated. 31- year-old spruce clones: 26, 31, A10, A15, A7, B10, B15, B6, V7, V9 were selected across Latvia. The stem diameters of spruce clones varied between 13.0 and 20.9 cm. The wood density of clones ranged from 361 to 443 kg/m<sup>3</sup>. Klason lignin content, depending on the clone, was between 27.0%-28.9%. Cellular UV microspectrophotometry of the non-infected tracheids displayed the typical lignin distribution with highest absorbance values in the cell corners (abs<sub>280 nm</sub> 0.80) and compound middle lamellae (abs<sub>280 nm</sub> 0.48), while secondary wall showed lower lignin absorbance values (abs<sub>280 nm</sub>0.29 - 0.35). The deposition of phenolic extractives in ray parenchyma and epithelial cells of resin canals were emphasized by a significantly higher UV-absorbance (abs<sub>280 nm</sub> 0.68 to 0.78) when compared to the cell wall associated lignin. The content of acetone-soluble extractives of spruce clones varied between 1.1% - 1.8%. The x-value (natural durability) for all spruce clones after exposure to C. <i>puteana</i> and <i>P. placenta</i>was >0.90 (durability class 5, not durable). Most of clones after degradation by G. <i>trabeum</i> had x-value > 0.90 with exception of clones B15 and V9 that showed x-value ≤ 0.90 (durability class 4, slightly durable). Natural durability of spruce clones did not correlate with stem diameter, density, content of lignin and extractives

Indentation of Juvenile Annual Growth Rings and their Impact on Morphology of Wood Cells

“…According to Swedish study, authors in Picea abies reported tracheid lengths to be 1.3 mm for JW, and 2.5 to 3mm in MW [17]. According to Latvian study, 31-years-old clones of Picea abies have a mean length of tracheids 2.4±0.2 mm and mean width of tracheids 31.7±1.5µm [18]. Similar results were found in 24-year-old Picea sitchensis trees come from region of British Columbia, Canada with a mean length of tracheids approx.…”

Wood anatomy of five species from Mozambique and its potential application

“…(vi) Structural use -the suitability of wood in internal or external structures is directly related to its natural durability, which depends on its anatomical structure and chemical composition (Irbe et al 2012). Wood with high percentage of parenchyma tends to have lower natural durability.…”

Variability in the Distribution of Middle Lamella Lignin in Secondary Vascular Tissues of Kenaf Stems

“…this feature is readily observable in the images obtained using transmission electron microscopy (tEM) of ultrathin sections stained with potassium permanganate (KMnO 4 ), a reagent widely used to contrast lignin in ultrastructural studies of secondary xylem, including wood. While UV microscopy may be considered the most appropriate and reliable method for detecting lignin at the microscopic level (Koch & Kleist 2001;Schmitt et al 2006;Irbe et al 2012), tEM microanalysis of wood samples after the lignin has been chemically marked with either Br or Hg is probably the most accurate high resolution and quantitative method available combining morphology at both low and high magnifications with chemical specificity (Eriksson et al 1988;Daniel & Nilsson 1987;Daniel et al 1991).…”