木雕文物的褐腐菌害

Degradation of wooden-carved Buddha caused by brown rot fungi

为对一尊唐代木雕佛像严重朽蚀的原因进行调查,用扫描电镜观察,对样品的综纤维素、木质素含量等进行分析测定,并对菌进行培养。实验结果表明,木材纤维中有菌丝,真菌孢子,经一定温湿度培养后,腐朽木材上的孢子有发展,说明该真菌在原介质上存活,在合适的环境条件下,将会继续起菌害作用。分析数据说明,综纤维素含量大大降低,木质素的相对百分比含量大大升高,这是综纤维素及其相伴生的戊聚糖受真菌破坏分解的结果。此等菌害的表现应该是属褐腐菌对木材破坏的结果。由于褐腐菌对木材短时间内就能产生强大的破坏力,因此,对木质文物的保护要特别重视褐腐菌的侵害。

A wooden - carved Buddha dated from Tang Dynasty stored in museum has decayed seriously, especially, at the lower portions of the Buddha. The cracks and fissures appeared all over the wooden statue. The degraded wood was extremely fragile and lost its strength. They can be easily crushed to dust - like powder. The fragment cracked down from the wood occasionally. The causes of the decay of the statue were examined by chemical analysis, SEM, and culture of fungi. From the SEM examination, the fungal hyphae and spores were found in the wood. After the culture, the spores were still surviving and sprouting. The results of chemical analysis showed that the lignin content of the decayed wood was more than that of the undecayed wood, and the contents of cellulose, hemicellulose were less than that of the undecayed wood. These showed that the cellulose and hemicellulose must be decomposed by fungi and the lignin left. The fungi that breakdown only cellulose produce the friability, so the degradation of the wooden carved Buddha must be caused by brown - rot fungi. One of the most destructive brown - rot fungi is Serpula lacrymans, also called 'dry - rot' . Timber damaged by this fungus has a typical cubical cracking and residual wood is brown. The similar symptom can be found on the other wooden carved Buddha. Brown - rot fungi depolymerize cellulose rapidly during incipient stages of wood colonization. Considerable loss of wood strength occurs very early in the decaying process. These fungi have serious impact on wooden cultural property. It is better to control the brown - rot fungi as early as possible.