摘要土传病害指植物的根茎部受到真菌，病毒和细菌等病原体的侵染后，导致植物大批量死亡的病害，对于农作物有毁灭性作用,给我国的农业发展带来了极大的限制。索拉胶是一种新型的β-1,3-葡聚糖，它可溶于水，安全无毒，且表现出抗氧化作用等生物活性，具有应用于食品、制药等行业的潜能。本实验主要将不同浓度的索拉胶和不同的播种方式组合到一起，以此来观察索拉胶对土壤菌群生长情况的影响，与对土传真菌的生长抑制作用。本次实验，主要应用到DNA提取技术，PCR扩增以及荧光定量PCR来准确检测索拉胶对土壤中菌群生长情况的影响。从而找到可以防治土传病害的方法。结果表明，索拉胶对抑制土壤真菌和尖孢镰刀菌有明显作用。 25744      
关键词  土传病害  β-1,3-葡聚糖  PCR  实时荧光定量PCR
毕业论文设计说明书外文摘要
Title  The influence of Salecan on soil microbial communities 
Abstract:
Soil-borne diseases means the root and stem of plants are infected by fungi, viruses and bacteria and other pathogens , which cause a large quantities of death even have a devastating effects for crops. It has brought a great restrictions to agricultural development in China. Salecan is a novel exopolysaccharide, which could be solubled in water and it is also safe and nontoxic. Furthermore ,it has wide bioactivities such as antioxidation and also has greatapplication potentials in food, pharmaceutical and other industries.This experiment will combine different concentrations of Salecan with different sowing methods , in order to observe the influence of Salecan on soil microflora growth, and the inhibition of soil-borne fungi’s growth. In this experiment, mainly use the extract technology of DNA, PCR amplification and quantitative PCR inorder to detect the infulence accurately. The results showed that Salecan plays a significant role in inhibiting soil fungi and Fusarium oxysporum’s growth.
Key words  soil-borne disease  β-1, 3- glucan PCR   QRT— PCR
目   次
1.绪论    1
1.1土传病害概述    1
1.1.1土传病害    1
1.1.2土传病害的影响    1
1.2尖孢镰刀菌的致病机理    2
2．土传病害的防治    3
2.2土传病害防治机理    3
2.3土传病原真菌的防治方法    4
2.4索拉胶简介    4
3.培养与提取    5
3.1尖刀镰孢菌的培养    5
3.2土壤总DNA提取    6
3.2.1实验材料    6
3.2.2实验步骤    7
3.2.3土壤总DNA提取结果    8
3.3DNA的OD值测定    9
4.PCR扩增    10
4．1影响PCR扩增的两个因素    11
4.2扩增结果    12
5.荧光定量PCR    16
5.1实时荧光定量PCR技术的基本原理    16
5.2荧光定量PCR检测尖孢镰刀菌和真菌的数量    16
5.3实验结果如下表    18
6.结果与讨论    20
6.1索拉胶对土壤真菌相对含量变化的影响    20
6.2索拉胶对土壤尖孢镰刀相对含量变化的影响    22
结论    24
致谢    25
参考文献    26
1.绪论
1.1土传病害概述
1.1.1土传病害
土传病害指植物的根茎部受到真菌，病毒和细菌等病原体的侵染后，导致植物大批量死亡的病害，对于农作物有毁灭性作用。大部分植物被这些病害第一次侵染时主要来自于温室土壤。并且可分为非专性寄生真菌与专性寄生真菌两大类，其中大多数的土传病菌都是真菌。举例如能够引起苗腐和猝倒病的真菌属于外生的从根部侵染根侵染真菌，属于非专性寄生，专性寄生病原真菌典型的象尖孢镰(Fusarium oxysporum)、黄萎轮枝孢(Verticillium alboatum)，这种病原真菌可以引起植物的萎蔫、枯死[1]。 索拉胶对土壤微生物菌群的影响:http://www.youerw.com/shengwu/lunwen_19674.html