The Study Of Fungal Diversity From Murals And Aerosol In Xu Xianxiu Tomb Of Northern Qi Dynasty

There are many heritage sites distributing widely around the world in each period of human history. These sites are common treasure of all mankind. Biodeterioration is a common problem at the historical and archaeological sites. A detailed inventory of microorganisms which is responsible for biodegradation of ancient paintings has become an integral part of restoration and prevention activities. The Xu Xianxiu Tomb (571AD) with large murals in high value at history, culture and archaeolog is the best well-preserved brick tomb of Northern Qi dynasty. However, since discovery, it has suffered biotic (micro-organisms, insects, root, mice etc.) and abiotic (temperature, humidity, etc.) damage. Scientists have done a lot careful researches about the surface of culture heritage, fungus is the main harmful micro-organism. But, the research about microorganism damaging Xu Xianxiu tomb’s murals is very little. Therefore, from the microbiological point, we had studied fungal diversity and concentration from aerosol and murals in Xu Xianxiu Tomb. This study aimed to provide a scientific support for preservation.In this study, a combination method of traditional cultured method and18S rRNA gene-based molecular techniques was used to investigate fungal diversity and concentration of aerosol samples, mural surface samples, and inner mural samples in Xu Xianxiu Tomb (Taiyuan, China). Then microflora, fungal spatial distribution, fungal composition, and their ambient determinant (eg, environmental factors) were further analyzed. The ability of these agents in degradating mural matrix (for example Calcium Carbonate) was determinated to further explore the damage mechanism of biodeterioration on murals. The main results are described as below.(1)3genera, which are Penicillium sp., Cladosporium sp. and Alternaria sp., were shared by aerosol samples, mural surface samples and inner mural samples, and totally took absolute advantage86.35%,88.67%,68.46%singly in these three samples. Meanwhile Neurospora sp., Epicoccum sp., Aspergillus sp. and other11genera were founded in the Xu Xianxiu Tomb, too.(2) It is completely that the fungal community from mural surface was included in aerosol microflora, but the fugal community from inner mural samples was different from them. And4rare species in inner mural samples took accountant of4.77%, which contains Phoma sp.(2.45±1.41%), Myrothecium sp.(0.15%±0), Exophiala sp.(0.60±0.50%), Chalastosporasp.(1.56±0.01%).(3) RDA triplots showed a strong diversity gradient on each main ordination axis. And the main environmental factors to impact airbone microflora were temperature, relative humidity and depth, but to murals was colorant only. (4) The experiment of determinating the ability of these fungi in degradating Calcium Carbonate showed that not all fungi could degrade Calcium Carbonate, the hydrolysis circle could be observed clearly only in five genera, which are Penicillium sp., Cladosporium sp., Myrothecium sp., Neurospora sp., and Aureobasidium sp. But the ability is different. Penicillium sp. and Cladosporium sp.(2dominant species) had showed a higher ability than other3genera. They could degrade CaCO3in the medium rapidly. Furthermore, with the extension of incubation time, the hydrolytic circle was increasing.The results showed that these fungi have potential ability to destroy murals, and their growth was affected by the environmental conditions. Therefore, in view of the imperative to protect Xu Xianxiu Tomb, we recommend that the environmental conditions (temperature, humidity, etc.) in tomb should be strictly controlled to reduce the bad influence from external environment (ventilation, visits, etc.). And microenvironment aerosol monitoring is so important and necessary that it should be as a strategy for the preventive conservation of monumental culture heritage. To sum up, in this paper, we mainly studied the community structure and distribution of cultural fungi from aerosol samples and mural samples in Xu Xianxiu Tomb. Meanwhile a preliminary assessment of their ability to destroy murals was made. These results are in high scientific value for protecting Xu Xianxiu Tomb, and provide the oretical guidance and scientific basis for heritage workers.