Inhibitory Effects Of Heartwood Extracts From Strong Decay-resistant Tree Species On Wood Preservation

The aim of this study was to evaluate the antifungal activities of heartwood extracts from the strong decay-resistant tree species,and empolder new wood preservative. The antifungal activities against the fungi of white rot,brown rot,soft rot and stain of total 16 extracts by extracting with four impregnants from the heartwood of Morus alba, Fraxinus mandshurica,Sabina chinensis and Larix prince rupprechtii were determined. The expectation of the study was to provide the basis for the application of the four tree species and the exploitation of wood preservation of high efficiency,low poison and green environmental protection.The results as following:(1) The antifungal activities of the extracts against Coriolus versicolor , Gloeophyllum trabeum,Chaetomium globosum and Botryodiplodia theobromae were mensurated by the growth rate method. The results showed that the extracts of Morus alba had the best inhibitive effect,which extracted by methanol, acetone and ethyl acetate had better effect on Coriolus versicolor , Gloeophyllum trabeum and Botryodiplodia theobromae than the others. At the concentration of 1g/L the inhibition rate of the ethyl acetate extract of Morus alba against the three fungal species causing white rot,brownand rot stain was over 85%,and at the concentration of 3g/L was 100%,with corresponding EC50 value at 0.173g/L,0.324g/L and 0.057g/L,respectively. Secondly,the ethyl acetate extract of Sabina chinensis had visible effect.(2) The preservation activity of the extracts was carried on by using extracts with better inhibition effect in lab,compared with the water soluble preservative,ACQ–D. Meanwhile,the antisepsis situation was observed by SEM. The result showed that the grade of the ethyl acetate extract of Morus alba against Coriolus versicolor reached gradeⅠat concentration of 8g/L,and the anti-blue stain efficiency on Botryodiplodia theobromae was 100% at concentration of 16g/L. When the grade reachedⅠ,the methanol,ethyl acetate extract of Morus alba and the ethyl acetate extract of Sabina chinensis against Gloeophyllum trabeum was at concentration of 16g/L.(3)△L of wood treated by different concentrations of extracts and ACQ-D after decay by Coriolus versicolor was decreasing with concentration increasing,but decay by Gloeophyllum trabeum had ruleless fluctuate,and△E had little change. The positive value of△a and△b showed the colour of the chips tend to red and yellow.(4) GC-MS analysis result showed that there were 45 kinds of substances in the methanol,acetone and ethyl acetate extract of Morus alba and the match degree of 16 kinds of substances preponderate over 90%. And the more kind of the components of the three extracts were ketones,aromatic compoumd and phenolic compounds,respectively. At the same time,it had 25 kinds of substances in the ethyl acetate extract of Sabina chinensis. Terpenoid,ketones and aromatic compoumd had more kinds than the others,and there were 9 kinds of substances which match degree exceeded 90%.