Bacterial decay in waterlogged archaeological compression wood varies with severity of compression wood

Abstract

Bacterial decay in compression wood (CW) tracheids of waterlogged archaeological wood (WAW) was investigated using light microscopy, confocal laser scanning microscopy, transmission electron microscopy (TEM), and TEM immunogold labeling. Erosion bacteria were identified as the main degraders, and the extent of cell wall degradation differed depending on the severity of CW tracheids (mild vs. severe). Mild CW tracheids showed preferential decay in the inner S2 layer, with the locally degraded and/or fragmented S3 layer remaining. In contrast, severe CW tracheids revealed gradual degradation of the cell wall from the erosion progressing from exposed faces of the cell wall as decay progressed. The overall decay was more extensive in mild than in severe CW tracheids, and degradation of the highly lignified outer S2 layer (S2L) was only detected in mild CW tracheids. TEM immunogold labeling of 1,4-β-galactan, homogalacturonan (HG), heteroxylan, and heteromannan epitopes showed that there was no preferential degradation of pectins and hemicelluloses by action of diffusible enzymes and/or agents through the un-decayed cell wall during bacterial decay, in both mild and severe CW tracheids. Inter-CW tracheid bordered pit membranes showed higher decay resistance than CW tracheid walls. Degradation of HG and heteromannan epitopes was suppressed in pit membranes.

Characterization of Microbial Decay and Microbial Communities in Waterlogged Archaeological Wood Excavated from the Wetland

“…국내에서는 신안선 선체의 마 미송(Pinus massoniana)과 신안선에 실려 있던 자단목 (Dalbergia spp.) 등에서 연부후 피해가 관찰되었다 (Kim, 1989;Kim et al, 2023).…”

Mechanical properties of compression wood from two fast-growth wood species pretreated with alkaline sulfites

“…The wood modi cation process can provide more options for outdoor and indoor applications (Ding et al 2022). Wood is modi ed by heat treatment (Ali et al 2021), chemical modi cation, surface modi cation (Song et al 2023), different impregnation, and densi cation techniques (Kim et al 2022). Densi cation causes cell walls to rupture and break down, leaving microscopic inspections and macroscopically visible cracks (Liang et al 2022).…”