摘要土壤微生物与植物根系之间相互作用，植物根系为土壤微生物提供养料，同时，土壤微生物促进植物生长。土壤微生物在农业中的应用已日益成为热门研究课题。本文通过稀释涂布划线分离方法分离出甘薯(Dioscorea esculenta (Lour.) Burkill)根际纯种细菌，观察菌落的形态特征，用通用引物进行PCR扩增16SrDNA，产物进行胶回收后进行16SrDNA测序，在EzTaxon Server2.1数据库中进行同源性比较，筛选出同源性较高的模式菌株，用MEGA5.0软件构建系统发育树。结果表明，甘薯根际可培养菌属有嗜气芽孢杆菌(Bacillus aerophilus)、高地芽孢杆菌（Bacillus altitudinis）、芽孢杆菌（Bacillus sp.）、土壤球菌属（Agrococcus lahaulensis）、变异棒杆菌（Corynebacterium variabile）、副球菌属（paracoccus sediminis）。采用植物组织培养法扩培无菌甘薯苗，同时加入已鉴定的甘薯根际的不同纯菌，相同条件下培养，观察甘薯苗生长状况。结果表明，B菌对甘薯苗生长有一定抑制作用，F菌对甘薯苗生长影响不显著。本文通过对徐州汉王甘薯田根际土壤微生物的鉴定与其对甘薯苗生长影响的研究，希望可以从土壤微生物方面找到提高甘薯产量的方法，为提高甘薯产量提供新思路。50703

该论文有图8幅，表5个，参考文献17篇。

毕业论文关键词：土壤微生物  16SrDNA  系统发育树  甘薯苗  植物组织培养

Isolation and Identification of Bacillus sp. and Other Bacteria and the Relationship these Bacteria and Sweet Potatoes

Abstract

Soil microbes and the root system of plants react mutually, the root system of plants give nourishment to the soil microbes, meanwhile, soil microbes is good for plants’ growth, the use of soil microbes in the agriculture is becoming hot research subject.In this paper,using microbial pure culture method to isolate the rhizosphere purified bacteria of sweet potatoes(Dioscorea esculenta (Lour.) Burkill),observe the character of colony morphology,augment 16SrDNA with universal primer, PCR product purified by gel extraction,16SrDNA sequencing,do homology comparison in the EzTaxon Server2.1 database,choose higher homology type strain,build phylogenetic tree in the MEGA5.0.The results show that,the rhizosphere bacteria of sweet potatoes are Bacillus aerophilus, Bacillus sp., Bacillus altitudinis, Agrococcus lahaulensis, Corynebacterium variabile, paracoccus sediminis.Using plant tissue culture method to augment sterile sweet potatoes, and put purified bacteria respectively into the sweet potatoes, culture under the same condition, and then observe the state of the plants with different bacteria.The results show that,B bacterium has an adverse effect on the growth of the sweet potatoes and F bacterium has no significant effect on the growth of the sweet potatoes.In this paper, through identification of soil bacteria of sweet potatoes in the Xuzhou Hanwang and researching the effect of these bacteria on the growth of sweet potatoes, hoping to find some new methods about soil microbe to improve the yield of sweet potatoes, to give new thoughts to improve the sweet potatoes.

Key words:soil microbes  16SrDNA  Phylogenetic trees  sweet potatoes  plant tissue culture

目  录

摘要 Ⅲ

Abstract Ⅳ

目录 V

图清单 Ⅵ

表清单 Ⅵ

1 绪论 7

2  材料与方法 8

2.1  土壤采集区概况 8

2.2 样品采集与处理 8

2.3 实验器材