Zur Zellwandstruktur von 1600 Jahre altem, wassergesättigtem Eichenholz

Abstract

Wasserges/ittigtes Eichenholz der sogenannten ,,Mainzer R6merschiffe" (4. lahrhundert n. Chr.) wurde mit einem Transmissionselektronenmikroskop auf Ver~inderungen in der Zellwandstruktur untersucht. Es zeigte sich fiir die meisten Zellen eine strukturell unbeeintr/ichtigte Mittellamelle und Sekund~irwand 3, die Sekund/irwandschichten Iund 2 ($1 und $2) liefgen hingegen einen deutlichen Strukturverlust erkennen. Hinsichtlich der wirkenden Mechanismen ergab die Untersuchung eine Beteiligung holzabbauender Bakterien. On the cell wall fine structure of 1600 year-old, water-saturated oak woodWater-saturated oak wood from the ,,Mayence Roman ships" (4 th century A.D.) was investigated by transmission electron microscopy. The studies on the cell wall fine structure revealed that in most cells the middle lamella and the innermost secondary wall layer ($3) remained structurally unaltered. On the other hand, the secondary wall layers Sl and S2 became heavily degraded. The characteristic degradation pattern indicates the involvement of bacteria.

Micromorphological Characteristics of Wood Biodegradation in Wet Environments: A Review

“…Information available on the decay micromorphology of buried archaeological woods suggests that bacteria and soft rot are their main degraders as the oxygen limiting conditions of burial exclude fast degrading basidiomycetes (Blanchette & Hoffmann 1993;Riess & Daniel 1997;Schmitt & Hoffmann 1998;Kim & Singh 1999). Bacterial erosion appears to be the main form of degradation in buried archaeological woods (Kim & Singh 1994;Blanchette et al 1991b;Donaldson & Singh 1990;, with attacks by tunnelling bacteria and soft rot fungi in some cases ) (Fig.…”

“…Under conditions that may be anoxic or where little oxygen is present, such as in deep mud, on ocean floors and in deep waters, wood is primarily degraded by bacteria (Singh et al 1990, in particular, erosion bacteria which appear to be highly tolerant of such conditions (Nagashima et al 1990a;. Similar, but less harsh, conditions with regards to the presence of oxygen can also support the activities of tunnelling bacteria and soft rot fungi (Riess & Daniel 1997;Santhakumaran & Singh 1992;Schmitt & Hoffmann 1998). These discoveries have rekindled interest among wood technologists, wood scientists and archaeologists in the process of timber decay under water-saturated conditions, so as to help develop strategies for prolonging the service life of wood in wet environments and restoring wooden artefacts of historical significance (Rowell & Barbour 1990).…”

Topochemical and transmission electron microscopic studies of bacterial decay in pine (Pinus sylvestris L.) harbour foundation piles

“…Methods such as transmission electron microscopy (TEM) and scanning electron microscopy (SEM) are well suited to reveal structural details of the degradation mechanism in bacteria infected woody tissues (Nilsson and Singh, 1984;Daniel and Nilsson, 1985;Singh and Butcher, 1986;Schmidt et al, 1987;Singh, 1989;Nilsson et al, 1992;Daniel, 1994;Schmidt and Liese, 1994;Liese et al, 1995;Schmidt, 1995;Daniel and Nilsson, 1998;Schmitt and Hoffmann, 1998;Björdal et al, 1999Björdal et al, , 2000Hoffmann et al, 2004;Schmitt and Melcher, 2004;Rehbein et al, 2008;Singh et al, 2009). To obtain topochemical information on bacterial cell wall degradation, special techniques like UV-microspectrophotometry (UMSP) must be applied.…”