【作者】 姜海燕；

【导师】 闫伟；

【作者基本信息】 内蒙古农业大学 ， 森林培育， 2010， 博士

【摘要】 土壤微生物是生态系统的重要组成部分,在能量流动、物质循环以及土壤的形成与熟化过程中均起重要作用,也是反应环境变化的敏感指示生物,其数量组成和种群结构是评价森林土壤质量的重要参数。因此研究内蒙古大兴安岭森林生态系统定位站地区兴安落叶松林土壤微生物的生态分布及土壤酶活性,对退化生态系统的恢复和治理及提高不同植被的生产力均有着重要的理论和实践意义。本文对内蒙古大兴安岭兴安落叶松林土壤微生物数量及种群结构进行研究,探讨了土壤微生物数量、土壤肥力、土壤酶间的相互关系;采用形态学与rDNA-ITS分子生物学技术相结合的方法对土壤优势真菌进行分类鉴定。主要研究结果如下:1、在兴安落叶松原始林与被干扰林中,土壤pH值在4.59-5.94间,属酸性土壤。土壤有机质含量比较高,且主要积聚在地表,除全钾外,土壤其它营养元素均是随着土层深度的增加,各营养元素含量呈下降的趋势,而全钾在各样地是随着垂直深度的增加,其含量逐渐增加。2、土壤微生物数量随季节呈现显著的变化。不同样地各类微生物的变化有所差异,表现为:①微生物总数与细菌:原始林各样地与被干扰林FLB样地微生物总数与细菌数量变化是7月>5月、9月,被干扰林的CL与SL样地微生物总数与细菌数量变化是5月>7月、9月;②真菌:除原始林的LLV样地,其它样地土壤真菌的变化是7月>5月>9月,原始林LLV样地真菌的变化是9月>5月>7月;③放线菌:原始林的LLV、BLV样地与被干扰林的CL样地放线菌数量变化是5月>7月、9月,原始林HLV样地与被干扰林LFB样地放线菌数量变化是7月>5月、9月,被干扰林SL样地放线菌数量变化是9月>5月、7月。土壤微生物数量的垂直分布规律是:随着土层深度的增加,各微生物数量呈递减的趋势,表现为0-10cm层>10-20cm层>20-30cm层。3、从兴安落叶松林中分离鉴定到细菌21属,以分枝小杆菌属(Ramibacterium)、芽孢杆菌属(Bacillus)、棒状杆菌属(Corynebacterium)、短杆菌属(Brevibacterium)为优势菌属;真菌21属,以青霉属(Penicillium)、曲霉属(Aspergillus)、毛霉属(Mucor)、木霉属(Trichoderma)为优势菌属;放线菌9属,以链霉菌属(Streptomyces)、诺卡氏菌属(Nocardia)为优势菌属。4、土壤微生物与理化性质的相关分析表明,土壤微生物总数、细菌与碱解氮呈极显著正相关(P<0.01),与全氮呈显著正相关(P<0.05)。土壤微生物间,细菌与微生物总数、真菌间呈极显著正相关关系(P<0.01),真菌与微生物总数间呈极显著正相关(P<0.01)。5、通过分子鉴定,青霉属(Penicillium)的14个不同菌株属于10个不同的种,其中有1个未确定到具体的种名;曲霉属(Aspergillus)的5个菌株属于5个不同的种;木霉属(Trichoderma)的4个菌株属于4个不同种,其中有2个为它的有性型,有1个未确定到具体的种名;毛霉属(Mucor)的3个菌株属于2个不同的种。6、土壤酶活性季节变化规律是:7月酶活性>5月、9月酶活性。在土壤剖面上,土壤酶活性均具有垂直变化规律,其变化是随着土层垂直深度的增加,酶活性逐渐降低,表现为0-10cm层>10-20cm层>20-30cm层。7、土壤酶活性与理化性质的相关分析表明,蔗糖酶与pH值呈显著负相关(P<0.05);蛋白酶与全磷、碱解氮呈显著正相关(P<0.05),与速效钾呈显著负相关(P<0.05);酸性磷酸酶与速效钾呈极显著负相关(P<0.01)。土壤酶活性间,多酚氧化酶与酸性磷酸酶呈显著正相关关系(P<0.05);蛋白酶与酸性磷酸酶呈显著正相关(P<0.05)。8、土壤酶活性与微生物的相关分析表明,蛋白酶与微生物总数、细菌数量间呈极显著正相关(P<0.01),酸性磷酸酶与微生物总数、细菌、真菌数量间呈显著正相关(P<0.05);蛋白酶与真菌数量间呈显著正相关(P<0.05)。更多还原

【Abstract】 Soil microorganisms are main parts of the forestry ecosystem, and play vital roles in energy conversion, material cycling, development and maturation of soil. They are sensitive indicatives of any variation in environmental conditions. Both species constitution and quantity of soil microorganisms come to be the key parameters for evaluating the soil quality. So investigating ecological distribution of soil microorganisms and activities of enzyme about Larix gmelinii forest in the national forestry ecosystem station of Inner Mongolia Great Xingan Mountains, they are important theoretical and practical significance in resuming and controlling degraded ecosystem and improving the productivity of different vegetation.In this study, we use traditional isolation methods of microorganisms to research the species constitution and quantity of soil microorganisms in Larix gmelinii forest of the Great Xingan Mountains, and to examine their relationships with soil microbial quantity, soil properties and soil enzymes. Morphology and rDNA-ITS are used to identify soil dominant fungi. The key results from these studies are summarized as follows:1. Soil pH value are 4.59-5.94 and acid in the Larix gmelinii virgin and disturbed forest. Soil organic matter is relatively high in the surface of soil. In addition to total K, other nutrients of soil are gradual lower with the increasing in vertical depth, but total K is contrary.2. The quantity of soil microorganisms show significant changes in different seasons. They are different in different plots, as follows:①The quantity of total microorganisms and bacteria: in all plots of virgin forest and LFB plot of distributed forest, they are July>May and September, but in CL and SL plots of disturbed forest, they are May>July and September.②The quantity of fungi: they are September>May>July in the LLV plots of virgin forest, and are July >May> September in the other plots.③The quantity of actinomycetes: they are May > September and July in LLV and BLV plots of virgin forest and CL plot of disturbed forest, and they are July>May and September in HLV plot of virgin forest and LFB plot of disturbed forest, but they are September>May and July in SL plot of disturbed forest. The quantity of soil microorganisms are gradual lower with the increasing in vertical depth, follow orders: 0-10cm layer>10-20cm layer>20-30cm layer.3. By using of traditional culture methods, bacteria isolated from Larix gmelinii forest belong to 21 genera, Ramibacterium, Bacillus, Corynebacterium and Brevibacterium are dominant genera; fungi are composed of 21 genera, Penicillium, Aspergillus,Mucor and Trichoderma are dominant genera; actinomycetes are classified into 9 genera,Streptomyces and Nocardia are main genera.4. Correlation analysis of soil properties and microbial quantity show that soil total microorganisms and bacteria have very significant positive correlation with available N (P<0.01), and have significant positive correlation with total N (P<0.05). Among soil microorganisms, bacteria have very significant positive correlation with total microorganisms and fungi (P<0.01), fungi have very significant positive correlation with total microorganisms (P<0.01).5. By using of molecular identification, 14 different strains of Penicillium belong to 10 different species; five different strains of Aspergillum belong to five different species; four strains of Trichoderma belong to four different species, and two species are its sexual stages; three different strains of Mucor belong to two different species.6. Seasonal variation of soil enzymes are July>May and September. The activities of soil enzymes are gradual lower with the increasing in vertical depth, follow orders: 0-10cm layer>10-20cm layer>20-30cm layer.7. Correlation analysis of soil enzymes and soil properties show that invertase has significant negative correlation with pH values (P<0.05), protease has significant positive correlation with total P and available N (P<0.05), and then has significant negative correlation with available K (P<0.05), acid phosphatase has very significant negative correlation with available K (P<0.01). Among the activities of soil enzymes, polyphenol oxidase has significant positive correlation with acid phosphatase (P<0.05), protease has significant positive correlation with acid phosphatase (P<0.05).8. Correlation analysis of soil enzymes and soil microorganisms show that the protease has very significant positive correlation with total microorganism and bacteria (P<0.01), acid phosphatase has significant positive correlation with total microorganism, bacteria and fungi (P<0.05), protease has significant positive correlation with fungi (P<0.05).更多还原