【作者】 杨丹玲；

【导师】 龚国淑；

【作者基本信息】 四川农业大学 ， 植物病理学， 2007， 硕士

【摘要】 本试验选取了采集自横断山北部高山区35个土样，用稀释平板法分离土样中的放线菌。研究了该区域土壤放线菌数量、类群及其物种多样性及其数量类群与土壤生态环境因子之间的关系；测试了土壤放线菌在拮抗病原菌方面的潜在能力及其发酵液在不同因素的影响下的抑菌效果差异。对该区域0～20cm土层放线菌数量的研究结果表明，横断山北部高山区，0～20cm土层样品中，分离到的放线菌数量为2.46×10⁵±2.86×10⁵，变化范围较大。不同土壤深度的土样中，土壤放线菌数量随深度的加深而减小。0～20cm土样中放线菌数量表现为林地(3.25×10⁵ cfu·g^-1干土)＞草地(2.27×10⁵cfu·g^-1干土)＞灌丛林地(1.28×10⁵ cfu·g^-1干土)；粘壤土(2.91×10⁵ cfu·g^-1干土)＞壤土(2.87×10⁵ cfu·g^-1干土)＞砂质壤土(2.15×10⁵ cfu·g^-1干土)＞粉砂质壤土(1.98×10⁵cfu·g^-1干土)＞粉砂质粘壤土(1.71×10⁵ cfu㈨·g^-1干土)。放线菌的数量虽然受海拔的影响，但是影响的程度却不大。35个土样中共分离到5个属，即链霉菌属、孢囊链霉菌属、诺卡氏菌属、小瓶菌属和小多孢菌属。其中，以链霉菌属为主，孢囊链霉菌属和诺卡氏菌属次之，还有少量的小瓶菌属和小多孢菌属。表层土中链霉菌的数量平均为1.27×10⁵ cfu·g^-1干土，分离频率达到100％。分离到的链霉菌被划分为8个类群，优势类群为灰褐类群，分离频率达到92.59％；其次是白孢类群，分离频率为85.19％。壤土和砂质壤土中的土壤放线菌都各有4个属，粘壤土和粉砂质壤土各有3个属，而粉砂质粘壤土最少，只有2个属。林地和草地各有4个属，灌丛林地却只有2个属。0～20cm的土层中链霉菌的类群比20～40cm土层中的链霉菌类群多。横断山北部高山区不同样点中土壤放线菌的物种丰富度、物种多样性指数、均匀度指数、优势度指数的值分别是2.0000±0.7845、0.1124±0.0359、0.0698±0.0223、0.0006±0.0004。而链霉菌属的物种丰富度、物种多样性指数、均匀度指数、优势度指数的值分别是4.3333±1.0742、0.1313±0.0427、0.0631±0.0206、0.0003±0.0002。来源于该区域的258株放线菌中，对立枯丝核菌有拮抗作用的菌株97株和齐整小核菌有拮抗作用的菌株11株。其中，链霉菌属是在拮抗放线菌中占有数量最多的，共有81株菌株对立枯丝核菌有拮抗作用和9株菌株对齐整小核菌有拮抗作用，分别占相应病原菌拮抗菌株总数的83.51％和81.82％pH7～8、28℃～32℃下振荡培养8d有利于菌株14-17产生抗生素；pH7、28℃下振荡培养8d有利于菌株8-16产生抗生素；pH7～8、28℃下振荡培养8d或4d有利于菌株16-15产生抗生素。更多还原

【Abstract】 35 soil samples were collected from the region of northern alp of Hengduan Mountains of Qinghai-Xizang Plateau. The soil actinomycetes were separated and identified. According to the quantities and the communities, the relationships between them and some environment factors were analyzed, respectively. The actinomycetes diversity was also studied. Potential which could antagonize to pathogen and the differences in different fermentation condition were also analyzed.The results showed that the quantity of actinomycetes was about 2.46×10⁵±2.86×10⁵ in upper （0～20cm）. At the same plot, there were more actinomycetes in upper than in deeper soil layers.Quantities of actinomycetes from high to low were as follows: in different regions, Zheduo Mountain(5.05×10⁴ cfu·g^-1dry soil)＞Songlinkou(2.34×10⁴ cfu·g^-1dry soil)＞Que’er Mountain(1.17×10⁴ cfu·g^-1dry soil). In different soil textures, clay loam(2.91×10⁵cfu·g^-1dry soil)＞loam soil(2.87×10⁵ cfu·g^-1dry soil)＞sand loam(2.15×10⁵ cfu·g^-1dry soil)＞powder sandy loam (1.98×10⁵ cfu·g^-1dry soil)＞heavy clayey soil (1.71×10⁵ cfu·g^-1dry soil); In different land utilization way, forest land(3.25×10⁵ cfu·g^-1dry soil)＞grass land(2.27×10⁵ cfu·g^-1dry soil)＞brush forest land（1.28×10⁵ cfu·g^-1）dry soil). Quantities of actinomycetes were changed with altitude, but the degree of the impact is not great. At the same plot, there were more actinomycetes in upper （0～20cm） than in deepersoil layers （20～40cm）.Based on characteristics of morphology, physiology-biochemistry and 16S rDNA sequence, 5 genera were identified among these isolates. These genera included Streptomyces, Streptosporangium, Nocardia, Ampulariella and Micropolyspora. Among these genera, Streptomyces was the first, Streptosporangium and Nocardia were next, and Ampulariella and Micropolyspora were the least. As far as quantity was concerned, Streptomyces was also the most, its value was 1.27×10⁵ cfu·g^-1dry soil and its separation frequency was 100%. Moreover, the Streptomyces included Griseofuscus, Albosporus, Aureus, Globisporus, Roseosporus, Verticillatus, Griseorubroviolaceus and Lavendulae. Among these, Griseofuscus and Albosporus were domination, and their separation frequencies were 92.59% and 85.19%, respectively. There were 4 genera in loam soil and sand loam, 3 genera in clay loam and powder sandy loam, 4 genera in forest land and grass land, and 2 genera in Brush forest land, respectively. At the same plot, Quantity of actinomycetes genera in upper （0～20cm） was more than these in deepersoil layers （20～40cm）.The abundance（S）, Shannon-wiener’s diversity （H’）, Pielou’s evenness （E） and dominance index （D） of the quantity of actinomycetes were different. Their values were 2.0000±0.7845, 0.1124±0.0359, 0.0698±0.0223, 0.0006±0.0004, respectively. And the abundance （S）, Shannon-wiener’s diversity （H’）, Pielou’s evenness （E） and dominance index（D） of Streptomyces were 4.3333±1.0742, 0.1313±0.0427, 0.0631±0.0206, 0.0003±0.0002, respectively.Among 258 isolates, there were 97 isolates had obvious antagonistic effects against Rhizoctonia solani and 11 isolates had obvious antagonistic effects against Sclerotium rolfsii. 83.51% and 81.82% of antimicrobial actinomycetes which had antimicrobial activity against the two plant pathogens were Streptornyces, respectively. And there were 81 isolates against Rhizoctonia solani, 9 isolates against Sclerotium rolfsii. Strain 14-17 had their strong inhibition activity with fermentation 6 days, the initative pH of 7～8, 28℃～32℃tempereature and the vibration raises. Whereas 8-16 with fermentation 8d, pH of 7, 28℃tempereature and the vibration raises. Wherase 16-15 with fermentation 8d or 4d, pH of 7～8, 28℃tempereature and the vibration raises.更多还原