Natural decomposition of hornbeam wood decayed by the white rot fungus Trametes versicolor

ABSTRACT The impacts of white-rot fungi on altering wood chemistry have been studied mostly in vitro. However, in vivo approaches may enable better assessment of the nature of interactions between saprotrophic fungi and host tree in nature. Hence, decayed and sound wood samples were collected from a naturally infected tree (Carpinus betulus L.). Fruiting bodies of the white rot fungus Trametes versicolor grown on the same tree were identified using rDNA ITS sequencing. Chemical compositions (cellulose and lignin) of both sound and infected wood were studied. FT-IR spectroscopy was used to collect spectra of decayed and un-decayed wood samples. The results of chemical compositions indicated that T. versicolor reduced cellulose and lignin in similar quantities. Fungal activities in decayed wood causes serious decline in pH content. The amount of alcohol-benzene soluble extractives was severely decreased, while a remarkable increase was found in 1% sodium hydroxide soluble and hot water extractive contents in the decayed wood samples, respectively. FT-IR analyses demonstrated that T. versicolor causes simultaneous white rot in the hornbeam tree in vivo which is in line with in vitro experiments.

摘要 白腐真菌对木材化学性质的影响大多已通过体外实验开展研究。然而，体内实验方法或可更精准地评估自然界中腐生真菌与寄主树木间相互作用的本质。为此，研究人员从一株自然感染的鹅耳枥（Carpinus betulus L.）上采集了腐朽木与健康木样本。借助核糖体DNA内部转录间隔区（rDNA ITS）测序技术，鉴定出生长于该植株上的白腐真菌云芝（Trametes versicolor）的子实体。随后对健康木与感染木的化学成分（纤维素与木质素）展开分析测定。采用傅里叶变换红外光谱（FT-IR spectroscopy）采集腐朽与未腐朽木材样本的光谱数据。化学成分分析结果显示，云芝对纤维素与木质素的降解量基本相当。腐朽木材中的真菌活动会导致其pH值显著下降。腐朽木材样本中，醇苯可溶性浸提物含量大幅降低，而1%氢氧化钠可溶性浸提物与热水可溶性浸提物的含量则分别出现明显提升。傅里叶变换红外光谱分析表明，云芝可在鹅耳枥体内引发同步型白腐，该结果与体外实验结论相符。