云南剑川海门口遗址饱水古木降解的微观构造分析

文中采用扫描电镜(SEM)和透射电镜(TEM)对海门口遗址饱水古木进行降解机理分析。结果表明:古木细胞次生壁收缩严重并与胞间层分离;胞间层保存较完好,呈连续网状。说明古木纤维素和半纤维素降解相对严重,木质素降解相对较轻。古木主要是受细菌降解,通过SEM和TEM均可见明显的细菌腐朽特征。细菌首先侵入细胞腔,再通过S3层侵入细胞壁内部。细胞壁内由于降解而产生的空隙在几十到几百纳米之间。饱水古木也受到了一定程度的真菌降解,但这类真菌主要降解古木内淀粉等物质,对细胞壁物质降解能力差,主要是使古木变色。

Microstructural analysis of the degradation of waterlogged archaeological wood from Haimenkou Sites in Jianchuan County, Yunnan Province

We analyzed the mechanism of degradation of waterlogged archaeological wood from Haimenkou Sites using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). These observations show that the secondary walls of wood cells shrink very seriously and are separated from the intercellular layers, but that the latter remain relatively intact, presenting a continuous network. The results indicate that the degradation of cellulose and hemicellulose is serious while that of lignin is relatively mild. The archaeological wood suffers mainly from bacterial degradation which is demonstrated by significant bacterial decay characteristics as determined by SEM and TEM observation. Bacteria first invade the cell lumen, and then invade the cell wall through the S3 layer. The cell wall lacuna due to degradation varies between tens to hundreds of nanometers. The archaeological wood is also degraded by fungi to a certain degree. With weaker ability to degrade cell wall materials, such fungi mainly degrade starch and other substances, making archaeological wood darker.