松嫩草地盐碱化对土壤纤维素降解菌特性的影响

发布时间：2018-06-11 13:26

本文选题：松嫩盐碱地 + 纤维素降解菌　；参考：《东北师范大学》2017年硕士论文

【摘要】：本研究以松嫩草地不同盐碱化程度的土壤为研究对象,对不同盐碱化土壤中的纤维素降解菌的类群及其特性进行了系统的研究与分析。研究中,分别从羊草草地(pH 8.68)、虎尾草草地(pH 9.47)和杂草草地(pH 10.03)筛选得到了纤维素降解菌,并对其进行了形态学、生物化学特性以及16S rDNA核酸序列的分析与鉴定;确定了不同盐碱化草地中纤维素降解菌类群;并在此前提下,对上述菌株的产酶特性及植物生长特性进行了系统研究。取得的研究成果如下:1.不同盐碱化土壤中纤维素降解菌的鉴定通过对所筛选的纤维素降解菌的形态学、生物化学特性以及16S rDNA核酸序列分析,对分离菌株进行了鉴定。对菌株的生长特性分析表明,其都在0-4%NaCl及PH7-11条件下生长良好。分离筛选共获得35株菌经16SrDNA核酸序列比对,去除相同菌株,鉴定后得到27株纤维素降解菌。将所有菌株的16S rDNA核酸序列提交至GenBank共得到27株菌的登录号。同时,在核酸序列分析基础上,构建了所有菌株的系统发育树。2.不同盐碱化土壤中纤维素降解菌优势类群的分析在已分离鉴定的27株菌中,羊草草地土壤特有纤维素降解菌共10株,虎尾草草地土壤特有纤维素降解菌共9株,杂草草地土壤特有纤维素降解菌共4株。其余4株纤维素降解菌为三种不同草地土壤中交叉共有的重复菌株,其中,链霉菌KY007170.1和节杆菌KY007166.1为虎尾草草地以及羊草草地共有的菌株,链霉菌KY007169.1和节杆菌KY007185.1为三种草地中共有菌株。这说明在盐碱土壤中,链霉菌和节杆菌分布范围更广,适应性更强。采用CMC平板对三种不同草地中纤维素降解菌进行分析,结果表明:在三种不同盐碱化程度草地中,丰度最高的菌株均为链霉菌,丰度分别为羊草草地(71.4%)、虎尾草草地(71.4%)以及杂草草地(85.7%)。由此我们得出,盐碱化草地中,链霉菌显示出具有较强的盐碱适应能力,是优势的纤维素降解菌类群。3.分离菌株的纤维素降解特性(1)产纤维素酶特性采用刚果红染色法对所分离菌株的纤维素酶活性进行了初步分析,同时采用DNS法对分离菌株产生纤维素酶活性进行了分析。结果表明,大多数菌株均产生胞外纤维素酶,其酶活性范围在1.47~6.08×10~(-2)IU之间;链霉菌属DS-22的纤维素酶活性最高,活性为6.08×10~(-2)IU。(2)产木聚糖酶特性采用DNS法对分离菌株产生木聚糖酶活性进行了分析。结果表明,大多数菌都产生胞外木聚糖酶,其活性范围在2.23~18.80×10~(-2)IU之间;微杆菌属DS-28木聚糖酶活性最高,活性为18.80×10~(-2)IU。4.分离菌株的固氮特性采用无氮纤维素平板对分离菌株的固氮活性进行了分析,结果表明,这些纤维素降解菌菌株在无氮源的纤维素平板上生长良好,是可降解纤维素的固氮菌。通过乙炔还原法对分离菌株固氮酶活性进行了检测与分析,所有菌株均可产固氮酶,固氮酶活性范围在36.29~112.08 nmoL·ml·h~(-1)之间。其中,链霉菌DS-18固氮酶活性最高,活性为112.08nmoL·ml·h~(-1)。5.分离菌株的促生特性对分离菌株的促生特性(产IAA、产铁载体、溶磷以及抑菌能力)进行了分析。结果表明:所有菌株均具有产IAA能力,范围在2.4~80.69mg/L之间,其中微杆菌DS-34产IAA含量最大,为80.69mg/L;6株菌具备铁载体产生能力,均属于链霉菌属;8株菌具备溶磷能力,包括7株为链霉菌属以及1株为微杆菌属;11株菌具抑菌活性,分别为7株为链霉菌属,2株节杆菌属,1株诺卡氏菌属及1株黄杆菌属。6.不同盐碱化程度的土壤理化性质及生物数量分析对不同盐碱化程度土壤的理化特性及生物量进行了分析。结果表明,随着土壤的盐碱程度增加,土壤中总氮以及有机碳含量不断减少;三种不同盐碱化程度草地土壤中可培养微生物数量分布情况均为:细菌放线菌纤维素降解菌真菌。7.分离菌株的植物促生实验从上述菌株中,挑选三株链霉菌DS-22、DS-2以及DS-30进行盆栽实验,研究它们对羊草的促生作用。盆栽实验结果表明,所有的单一菌株处理组的效果较对照组促生作用明显,而混合菌株组的促生效果较单一菌株处理组促生作用更明显。研究结果显示了这些纤维素降解菌具有良好地促生作用。
[Abstract]:In this study, the groups and characteristics of cellulose degrading bacteria in different salinized soils were studied and analyzed in different saline alkaline soil. Cellulose degrading bacteria were screened from Leymus chinensis grassland (pH 8.68), pH 9.47 and pH 10.03. The morphology, biochemical characteristics and 16S rDNA nucleic acid sequence were analyzed and identified, and cellulose degrading bacteria groups in different saline alkali grassland were determined. Under this premise, the enzyme production and plant growth characteristics of the above strains were systematically studied. The results obtained are as follows: 1. fiber in different salinized soils The identification of the isolated strains of cellulose degrading bacteria was identified by the analysis of the morphology, biochemical characteristics and 16S rDNA nucleic acid sequence of the screened cellulose degrading bacteria. The analysis of the growth characteristics of the strain showed that all of the strains grew well under the conditions of 0-4%NaCl and PH7-11. The separation and screening of 35 strains were obtained by the 16SrDNA nucleic acid sequence ratio. After the identification of the same strain, 27 cellulose degrading bacteria were obtained. The 16S rDNA nucleic acid sequence of all the strains was submitted to GenBank to get the login number of 27 strains. On the basis of the nucleotide sequence analysis, the analysis of the dominant groups of cellulose degrading bacteria in the phylogenetic tree.2. of all strains was divided into the analysis of the dominant groups of cellulose degrading bacteria in different saline alkali soils. Among the 27 isolates, there were 10 endemic cellulose degrading bacteria in Leymus chinensis grassland, 9 strains of cellulose degrading bacteria endemic to the grassland soil, 4 strains of cellulose degrading bacteria in the weed grassland, and the remaining 4 strains of cellulose degrading bacteria in three different grassland soils, including Streptomyces KY007170.1 and ganglion The bacteria KY007166.1 is a common strain of the grass grassland and the Leymus chinensis grassland. The Streptomyces KY007169.1 and the Bacillus KY007185.1 are three kinds of grassland. This shows that in the saline alkali soil, the Streptomyces and Arthrobacter are more widely distributed and more adaptable. The results of the analysis of the cellulose degrading bacteria in three different grassland by using the CMC plate are analyzed. The results showed that among the three different salinity grassland, the highest abundance strains were Streptomyces, the abundance was 71.4% of Leymus chinensis grassland (71.4%), the grass grassland (71.4%) and the weedy grassland (85.7%). Thus, we concluded that the Streptomyces showed strong salt alkali adaptation ability and the dominant cellulose degrading bacteria.3. score in the saline alkali grassland. Cellulose degradation characteristics (1) produced cellulase from the strain (1), the cellulase activity of the isolated strain was preliminarily analyzed by the Congo red staining method. Meanwhile, the cellulase activity of the isolated strain was analyzed by the method of DNS. The results showed that most of the strains produced extracellular cellulase, and the activity range of the enzyme was in 1.47~6.. Between 08 * 10~ (-2) IU, the cellulase activity of Streptomyces DS-22 was the highest, the activity was 6.08 x 10~ (-2) IU. (2) xylanase, and the xylanase activity of the isolated strain was analyzed by DNS method. The results showed that most of the bacteria produced extracellular xylanase, and the activity range was between 2.23~18.80 * 10~ (-2) IU. The activity of the xylanase activity was the highest, the activity was 18.80 * 10~ (-2) IU.4. isolation strain. The nitrogen fixation activity of the isolated strain was analyzed by the nitrogen free cellulose plate. The results showed that the cellulose degrading bacteria grew well on the non nitrogen source cellulose plate and were the nitrogen fixing bacteria that degrade cellulose. The acetylene reduction method was used. The activity of nitrogen fixing enzyme of the isolated strain was detected and analyzed. All the strains could produce nitrogenase and the activity range of nitrogenase was between 36.29~112.08 nmoL ml. H~ (-1). Among them, the Streptomyces DS-18 nitrogenase activity was the highest, and the activity was the growth promoting characteristics of 112.08nmoL. Ml. H~ (-1).5. isolates. The results showed that all the strains had the ability to produce IAA, with the range of 2.4~80.69mg/L, of which the DS-34 produced the maximum IAA content, 80.69mg/L, and 6 strains possessed the ability to produce iron carriers, all of which belonged to the Streptomyces, and the 8 strains had the ability to dissolve phosphorus, including 7 strains of Streptomyces and 1 strains. Bacilli; 11 strains of bacteriostasis, 7 strains of Streptomyces, 2 strains of Arthrobacter, 1 strains of Nocardia and 1 strains of.6. in different salinization levels of soil physical and chemical properties and biomass analysis of different salinity soil physical and chemical properties and biomass were analyzed. The results showed that with the salinity of the soil, the degree of salt and alkali degree. The content of total nitrogen and organic carbon in the soil decreased continuously, and the number distribution of the cultivated microbes in the three different salinity grassland soils were all: the plant growth promoting experiment of bacterial actinomycetes cellulose degrading fungi.7. isolates from the above strains, three strains of Streptomyces, DS-2 and DS-30 were selected for pot experiments. The results of pot experiments showed that the effect of all single strain treatment group was more obvious than that of the control group, and the effect of the mixed strain group was more obvious than that of the single strain treatment group. The results showed that the cellulose degrading bacteria had a good promoting effect.
【学位授予单位】：东北师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S812.2

【参考文献】