| 木质素降解真菌的筛选及其对森林地表可燃物的降解效果 |
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| 引用本文： | 孙思琦,瓮岳太,邸雪颖,刘雪峰,杨光.木质素降解真菌的筛选及其对森林地表可燃物的降解效果[J].中南林业科技大学学报,2021(1). |
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| 作者姓名： | 孙思琦 瓮岳太 邸雪颖 刘雪峰 杨光 |
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| 作者单位： | 东北林业大学林学院;东北林业大学森林生态系统可持续经营教育部重点实验室 |
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| 基金项目： | “十三五”国家重点研发计划项目子课题(2017YFD0600106-2);国家自然科学基金项目(31870644)。 |
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| 摘 要： | 【目的】筛选帽儿山人工林地表可燃物中的木质素降解真菌,探究木质素降解菌对不同森林地表可燃物的分解效果,以期找到能够有效降解森林可燃物的真菌菌种,为应用生物降解方法降低森林地表可燃物载量从而降低森林火灾发生概率与森林火险指数提供理论依据和基础数据。【方法】采集东北林业大学帽儿山实验林场尖砬沟森林培育实验站的落叶松、胡桃楸、水曲柳纯林与胡桃楸-落叶松、水曲柳-落叶松混交林内的凋落叶,采用添加抗生素的麦芽浸粉(MEA)培养基进行真菌的分离培养,之后采用愈创木酚平板显色法进行初筛,根据测定菌株的显色情况及菌落圈与显色圈比值筛选高活性木质素降解酶菌株,复筛利用苯胺蓝平板脱色法对菌株木质素氧化酶系进行定性测定,对2次筛选获得的菌株进行形态学及分子鉴定,然后以胡桃楸、水曲柳、落叶松3种可燃物样品作为分解基质,接入木质素降解菌单一及混合菌液,于28℃恒温培养7 d,分别测定经培养后基质中的木质素含量,分析木质素分解规律。【结果】由MEA培养基筛选出的9株真菌有5株在PDA-愈创木酚培养基上发生了显色反应,且菌株B6和Y3的R/r <1,即该2株菌能优先降解木质素;苯胺蓝平板脱色试验结果显示菌株B6和Y3均可使培养基蓝色褪去,即均具有LiP与MnP酶活性;经形态学及分子鉴定,菌株B6为白囊耙齿菌Irpex lacteus,菌株Y3为桦褶孔菌Lenzites betulinus;地表可燃物样品降解试验结果显示,经单一菌液与两者混合菌液培养后,样品中木质素含量均有下降,且经混合菌液处理后的3种可燃物基质表现出相对较好的降解效果;3种基质降解率从高到低依次为水曲柳>胡桃楸>落叶松;菌种Y3对木质素的降解效果较菌种B6好。【结论】混合菌液对可燃物中木质素的分解能力较单一菌液强;菌株B6和Y3之间无拮抗作用,混合后产生协同效应,使木质素降解酶系活力提高,从而可提高木质素降解率;菌种Y3降解能力强于B6;可燃物样品中木质素降解效果因基质不同而存在差异,阔叶可燃物比针叶可燃物易分解。经筛选出的木质素降解菌能有效降解可燃物中的木质素,可在一定程度上减少森林地表可燃物载量,从而降低森林火灾风险。
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| 关 键 词： | 木质素 降解 真菌 森林地表可燃物 人工林 |
Screening of lignin-degrading fungi and their degradation effect of forest surface fuel |
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| SUN Siqi,WENG Yuetai,DI Xueying,LIU Xuefeng,YANG Guang.Screening of lignin-degrading fungi and their degradation effect of forest surface fuel[J].Journal of Central South Forestry University,2021(1). |
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| Authors: | SUN Siqi WENG Yuetai DI Xueying LIU Xuefeng YANG Guang |
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| Institution: | (College of Forestry,Ministry of Education,Northeast Forestry University,Harbin 150040,Heilongjiang,China;Key Laboratory of Sustainable Forest Ecosystem Management,Ministry of Education,Northeast Forestry University,Harbin 150040,Heilongjiang,China) |
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| Abstract: | 【Objective】In order to find efficient lignin-degrading fungi to degrade forest fuel and provide theoretical basis and basic data for the application of biodegradation method to reduce forest surface fuel load and thus reduce the probability of forest fire and forest fire risk index, this paper screened lignin-degrading fungi in the surface fuel of Maoershan artificial forest and explored the decomposition effect of lignin-degradation fungi on different forest surface fuel.【Method】The litter leaves of pure Larix olgensis, Juglans mandshurica, Fraxinus mandshurica plantations, Juglans mandshurica-Larix olgensis forest and Fraxinus mandshurica-Larix olgensis forest were collected from Jianlagou forest cultivation experimental station in Maoershan experimental forest farm of Northeast Forestry University. The fungi were isolated and cultured on the medium of malt extract powder(MEA) added with antibiotics.After that, guaiacol coloration method was used to primarily screen the strains with high lignin-degrading enzyme activity according to the coloring reaction results and the ratio of colony diameter to colored ring diameter.Then, the aniline blue decolorization method was used to determine the lignin oxidase system of the strains.Morphological and molecular identification were carried out on the strains screened twice.Then, three kinds of fuel samples of Juglans mandshurica, Fraxinus mandshurica and Larix olgensis were used as decomposition substrates, and the single and mixed fungal suspensions of lignin-degrading fungi were added.The content of lignin was determined and the lignin decomposition rule was analyzed after incubation at 28℃ for 7 days.【Result】Five of the nine fungi screened from MEA medium show color reaction on PDA-GU medium, and the R/r of strains B6 and Y3 are less than 1, that is to say, the two strains can preferentially degrade lignin.The results of aniline blue decolorization test show that strain B6 and Y3 can make the blue of the medium fade, which means both strains have enzyme activity of LiP and MnP. Strain B6 was Irpex lacteus and strain Y3 was Lenzites betulinus by morphological and molecular identification.The degradation test results of surface fuel samples show that the lignin content of the samples all decreased after culturing by single and mixed fungal suspensions, and three fuel substrates treated by the mixed fungal suspension show relatively better degradation effect. The degradation rate of the three substrates from high to low is Fraxinus mandshurica > Juglans mandshurica > Larix olgensis.The degradation effect of strain Y3 on lignin is better than that of strain B6.【Conclusion】The mixed fungal suspension has a stronger ability to decompose lignin in forest fuels than the single fungal suspensions. There is no antagonistic effect between strains B6 and Y3, and synergistic effect is produced after mixing, so that the activity of lignin-degrading enzyme system is improved, thereby improving the degradation rate of lignin. Strain Y3 has stronger degradation ability than B6. The degradation effect of lignin in forest fuel samples varies from substrates, and broad-leaf fuels are more susceptible to decomposition than coniferous fuels. The screened lignin-degrading fungi can effectively degrade the lignin in forest fuels and reduce the forest fuel load to a certain extent, thus reducing the risk of forest fire. |
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| Keywords: | lignin degradation fungi forest surface fuel plantations |
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