绿肥—烟草轮作对土壤细菌多样性和烟草青枯病发生的影响研究

发布时间：2018-07-05 01:21

本文选题：绿肥 + 土壤细菌　；参考：《湖南农业大学》2016年硕士论文

【摘要】：烟草是我国重要的经济作物之一,湘西是湖南省主要烟草产区,目前湘西自治州烟田连作障碍日益凸显,土传性病害普遍发生。绿肥能够提高土壤肥力和作物产量,在农业生产中具有重要地位,但其对湘西烟田土壤微生物以及烟草健康的影响尚不明确。本研究从湖南省湘西州烟草产区的烟田采集土壤样品(单种烤烟,黑麦草-烟草轮作,豌豆-烟草轮作和油菜-烟草轮作),对土壤性质进行测定并利用16S rRNA高通量测序研究土壤细菌的多样性,结合生物信息学分析得出了一系列研究结果。结果表明,绿肥-烟草轮作对于土壤性质、细菌群落和烟草青枯病发病率有显著影响：1.测定采集的土壤样品的pH值、含水量、总C和总N以及元素的含量,方差分析表明施用绿肥-烟草轮作能够明显提高土壤中碳和氮的含量。其中,以黑麦草对土壤总氮含量的提升最为明显,豌豆对土壤总碳含量的提升最为明显。施用绿肥后对于土壤中Fe、Zn和Co等元素含量并无明显影响,但Ca的含量则明显增加,以黑麦草组的提升最大。对照组中的含水量最高,达17%。油菜组和豌豆组的pH值高于对照组,并具有显著性差异。黑麦草组的pH平均值虽然高于对照组平均pH值但与对照组并无显著差异。2.通过去趋势对应分析(DCA)和不相似性分析发现各组烟田土壤间的细菌群落结构存在显著差异。统计分析表明各组的主要优势细菌组成也存在显著差异,例如,在门水平上,对照组中变形菌和放线菌的相对丰度更高,而泉古菌的丰度在油菜组中更高；酸杆菌的丰度在豌豆组中最高,在对照组中最低。而测序结果也表明,绿肥-烟草轮作能显著提高烟田土壤细菌多样性。3.采用绿肥品种尤其是黑麦草绿肥与烟草轮作的烟田中,土壤细菌群落间接的影响使烟草青枯病的发病率有所下降。一方面,研究发现一些微生物种群对于烟草疾病具有潜在的诱导或抑制效果,例如变形菌门下的两个分属Dokdonella和Rhodanobacter的丰度和烟草发病率呈正相关,而酸杆菌门下的两个分属Acidobacteira_Gp4和Gp6的生物丰度和烟草发病率呈负相关。另一方面,土壤细菌又明显受到包括pH、土壤中C和N等的土壤性质的影响。
[Abstract]:Tobacco is one of the important cash crops in our country. Xiangxi is the main tobacco producing area in Hunan Province. At present, the continuous cropping obstacle of tobacco field in Xiangxi Autonomous Prefecture is increasingly prominent, and soil-borne diseases are common. Green manure, which can improve soil fertility and crop yield, plays an important role in agricultural production, but its effect on soil microorganism and tobacco health in tobacco field in western Hunan is not clear. In this study, soil samples (single flue-cured tobacco, ryegrass and tobacco rotation) were collected from tobacco fields in Xiangxi Prefecture, Hunan Province. Pea-tobacco rotation and rapese-tobacco rotation), soil properties were determined and 16s rRNA high-throughput sequencing was used to study the diversity of soil bacteria. A series of results were obtained by bioinformatics analysis. The results showed that green manure and tobacco rotation had significant effects on soil properties, bacterial community and tobacco bacterial wilt incidence. The pH value, water content, total C, total N and element contents of the collected soil samples were determined. The variance analysis showed that the application of green manure and tobacco rotation could significantly increase the carbon and nitrogen content in the soil. Among them, ryegrass had the most obvious increase in soil total nitrogen content and pea had the most obvious increase on soil total carbon content. Application of green manure had no significant effect on the contents of Fe, Zn and Co in soil, but the content of Ca increased significantly, especially in ryegrass group. The water content in the control group was the highest (17%). The pH value of rape group and pea group was higher than that of control group, and the difference was significant. Although the average pH of ryegrass group was higher than that of control group, there was no significant difference between ryegrass group and control group. By means of DCA and dissimilarity analysis, it was found that there were significant differences in bacterial community structure among tobacco soil in each group. Statistical analysis showed that there were significant differences in the composition of dominant bacteria among the three groups. For example, the relative abundance of Proteus and actinomycetes in the control group was higher than that in the rapeseed group at the gate level, but the abundance of Quangu was higher in the rapeseed group. The abundance of acidobacterium was the highest in pea group and the lowest in control group. The results of sequencing also showed that green manure and tobacco rotation could significantly improve the bacterial diversity of tobacco soil. The indirect effect of soil bacterial community on tobacco field with green manure especially ryegrass green manure and tobacco rotation decreased the incidence of tobacco bacterial wilt. On the one hand, the study found that some microbial populations had potential induction or inhibition effects on tobacco disease, such as the abundance of two subspecies of Proteus, Dokdonella and Rhodanobacter, positively correlated with tobacco morbidity. The bioabundance of Acidobacter iraa and Gp6 were negatively correlated with the incidence of tobacco. On the other hand, soil bacteria were significantly affected by soil properties, including pH, C and N in soil.
【学位授予单位】：湖南农业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：S154.3;S435.72;S55

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