Microscopy and Analytical Pyrolysis of Paleowood fromNothofagus dombeyiandAmomyrtus luma

Abstract

13,000-year-old wood pieces from Amomyrtus luma and Nothofagus dombeyi from southern Chile were investigated by light and electron-microscopy. Determination of the lignin/carbohydrate composition was performed by analytical micropyrolysis. Sl ans S2 layers of the cell walls were found to be heavily degraded, whereas compound middle lamellae and S3 layers appeared almost unchanged. Analytical micropyrolysis revealed that the degradation was mainly restricted to carbohydrates and to a very limited extent to lignin compounds. Both microscopy and micropyrolysis providcd no clear evidence, whether degradation was dominated by biotic or abiotic processes.

Radial Striation of the S2Layer in Mild Compression. Wood Tracheids ofPinus radiata

“…Despite some reservations to the specificity of KMnO 4 for lignin (Bland et al 1971;Hoffmann and Parameswaran 1976), this stain has been widely used to contrast lignin in plant and wood cell walls (Hepler et al 1970;Maurer and Fengel 1990;Diaz-Vaz et al 1991;Blanchette et al 1994;Donaldson 1995;Singh 1996). Recognising this, we assume for the P. radiata mild compression wood that lighter areas (light striations) are less lignified than darker areas (dark striations) within the mosaic pf variable densities in the S 2 wall.…”

Zur Zellwandstruktur von 1600 Jahre altem, wassergesättigtem Eichenholz

“…In dem untersuchten Probenmaterial liegt somit ein Holzabbau durch Bakterien vor, der in vergleichbarer Form bereits ftir andere arch/~ologische H61zer (u.a. Blanchette et al 1990;Diaz-Vaz et al 1991) und auch rezentes Holz (Singh und Butcher 1990) festgestellt wurde. Often bleibt hingegen, in welchem Ausmafl und zu welchem Zeitpunkt der bakterielle Abbau zurn Masseverlust beigetragen hat, zumal auch abiotische Mechanismen beispielsweise in Form einer Hydrolyse der Kohlenhydrate yon arch~iologischen Fundstiicken bekannt sind (Hoffmann und Parameswaran 1982;Blanchette und Simpson 1992).…”

Investigations on the Reaction Mechanism of Xylanases and Mannanases on Sprucewood Chemical Pulps

“…Therefore missing or minor changes in the GPC elution curves do not necessarily prove that no hydrolysis has taken place. The extracts of the enzyme treated kraft-AQ pulps were analysed for carbohydrates and lignin by pyrolysis-GC (Diaz-Vaz et al 1991), followed by partial least square regression analysis (Table 5, Bremer 1991). It becomes apparent that the extracts of enzyme-treated pulps have a higher pentose content.…”