石油污染物降解菌群的根际富集及其降解特性研究

发布时间：2018-01-28 11:22

本文关键词： 石油污染根际菌群豆科植物根瘤菌盆栽试验　出处：《西北农林科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：石油污染严重地危害着土壤环境、农作物的生长和人类的健康。建立高效、环保的石油污染修复技术是目前研究的迫切需求。本论文通过盆栽实验,在农田土壤和石油污染土壤中分别种植12种豆科植物,利用植物生长自然驯化根际菌群和建立共生,测定根际菌群对菲的降解效率,获得高效降解的菲的豆科植物-根际菌群体系;然后通过16S rDNA高通量测序技术,解析根际降解菌群的结构;再通过16S rDNA序列对分离的根瘤菌进行系统发育分析,探究石油污染对豆科植物-根瘤菌共生关系的影响。结果如下:通过种植豆科植物获得24个根际菌群(包括污染土和农田土),测定和比较菌群对初始浓度为250 mg/L的菲的5天后降解效率,结果显示从石油污染土壤中驯化的小冠花、豇豆、百脉根和红三叶4个根际降解菌群对菲降解效率均在65%以上,与农田土壤获得的根际菌群相比,降解效率均提高30%以上,其中从石油污染土壤中驯化的小冠花根际菌群降解效率高达80%,与从农田土壤获得的根际菌群相比,降解效率提高了67%。通过对根际土DNA进行16S rDNA V4-V5区高通量测序分析,发现在石油污染土中富集的根际菌群与在农田土中富集的根际菌群在群落结构上具有显著差异,其中,小冠花、豇豆、百脉根和红三叶在石油污染土富集的根际菌群差异显著的物种为α-变形菌纲(Alphaproteobacteria)和γ-变形菌纲(Gammaproteobacteria),而在农田土中则为β-变形菌纲(Betaproteobacteria),可见,在石油污染土中,差异显著的物种α-变形菌(Alphaproteobacteria)和γ-变形菌纲(Gammaproteobacteria)与菲降解效率有关。通过对根瘤菌的分离纯化,发现在石油污染土壤与农田土壤中,仅从豇豆和红三叶分离到了根瘤菌,其中从豇豆中分离的根瘤菌均归属于Bradyrhizobium,从红三叶中分离的根瘤菌均归属于Rhizobium,说明石油污染对豇豆、红三叶与根瘤菌的匹配类型没有影响,只是影响了根瘤数量。在石油污染土壤中,百脉根、柠条、刺槐等植物没有结瘤,可见,石油污染抑制了百脉根、柠条、刺槐等植物与根瘤菌共生关系的建立。
[Abstract]:Oil pollution seriously endangers the soil environment, crop growth and human health. It is an urgent need to establish efficient and environmentally friendly oil pollution remediation technology. Twelve species of legumes were planted in farmland soil and petroleum contaminated soil. The natural domestication and symbiosis of rhizosphere microflora were used to determine the degradation efficiency of phenanthrene. The biodegradable phenanthrene legume rhizosphere flora system was obtained. Then the structure of the rhizosphere degrading bacteria was analyzed by 16s rDNA high-throughput sequencing technique. The phylogeny of isolated rhizobia was analyzed by 16s rDNA sequence. To explore the effect of petroleum pollution on the symbiotic relationship between legumes and rhizobia. The results are as follows: 24 rhizosphere flora (including contaminated soil and farmland soil) were obtained by planting legumes. The degradation efficiency of phenanthrene at initial concentration of 250 mg/L was determined and compared after 5 days. The results showed that cowpea was domesticated from petroleum contaminated soil. The degradation efficiency of phenanthrene was more than 65% in the four rhizosphere biodegradable colonies of Baimai root and red clover, and the degradation efficiency was 30% higher than that of the rhizosphere flora obtained from farmland soil. Among them, the degradation efficiency of rhizosphere microflora domesticated from petroleum contaminated soil was as high as 80%, which was compared with that obtained from farmland soil. The degradation efficiency was increased by 67.The high throughput sequencing analysis of 16s rDNA V4-V5 region was carried out on DNA in rhizosphere soil. It was found that there were significant differences in community structure between rhizosphere microflora enriched in petroleum contaminated soil and rhizosphere bacteria enriched in farmland soil, among which, small crown flower, cowpea. The species of Alphaproteobacteria and 纬 -Proteobacteriae that are enriched in petroleum contaminated soil are the species of Alphaproteobacteria. Gamma proteobacteria. But in the farmland soil is 尾 -Proteobacter teriae, we can see, in the oil-contaminated soil. Alphaproteobacteria) and Gamma proteobacteria (Gamma proteobacteria). Related to the degradation efficiency of phenanthrene. Through the isolation and purification of rhizobia. It was found that rhizobia were isolated only from cowpea and red clover in oil-contaminated soil and farmland soil, and rhizobia isolated from cowpea belonged to Bradyrhizobium. All rhizobia isolated from red clover belong to Rhizobium, indicating that oil pollution has no effect on matching types of cowpea, red clover and rhizobia. In the soil polluted by oil, there were no nodules in the soil, such as Caragana korshinskii, Robinia pseudoacacia and so on. It can be seen that oil pollution has inhibited the establishment of symbiotic relationship between rhizobia, Caragana, Robinia and other plants.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X17;X53

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