湘西植烟土壤真菌多样性研究

发布时间：2018-06-06 16:23

本文选题：烟草 + 连作障碍　；参考：《湖南农业大学》2015年硕士论文

【摘要】：连作障碍在烟草上称之为烟草连作障碍,烟草重茬种植后会出现生长迟缓、植株矮小、产量品质降低、土传病虫害加重的现象。目前我国的烟草栽培也存在大面积连作的情况,连作障碍危机每年对行业带来的直接和间接的经济损失高达40亿元。加强对烟草连作机理的研究,以减轻和避免连作造成的损失,对当前我国乃至全球烟草业发展都有着重要的经济和社会意义。本研究以湖南省湘西自治州三个烟区的烟田土壤为研究对象,采用高通量测序方法分析不同连作年限、不同轮作方式和不同种类绿肥还田等三种耕作制度下烟田土壤中烟草根际真菌的多样性和群落结构；并利用选择性培养基对土壤样品中的可培养根际细菌和真菌进行分离筛选和计数,研究不同地区、不同发病程度的地块烟草根际微生物群落的变化。结果表明：(1)不同的耕作制度下,四个组中根茎类病害发病盛期微生物的多样性和均一度都明显降低,其中烟草连作组和烟草-玉米轮作的多样性和均一度都高于烟草-百合轮作和烟草-萝卜轮作组。(2)不同连作年限下,连作7年的处理中发病盛期的物种数高于冬闲期；连作4年和12年都是冬闲期高于发病盛期；从均一度看,所有处理中发病盛期的多样性和均一度都低于冬闲期,且随连作年限的增加而升高。(3)不同种类绿肥还田的处理中,发病盛期的物种数都低于冬闲期,箭舌箭舌豌豆还田的根际真菌群落在发病盛期的多样性和均一度高于冬闲期,其他三组都是冬闲期的多样性和均一度较高。对照组中微生物的多样性和均一度最高,箭舌豌豆绿肥组的多样性和均一度最低。各处理根际可培养真菌和细菌的离体培养结果表明：(1)轮作可显著影响土壤中可培养细菌和真菌的数量。烟草-玉米轮作土壤中的可培养细菌数量最多,达到9.38×10~7CFU/g干土,其次是连作与烟草-玉米轮作,最少的是烟草-萝卜轮作,数量为1.15×10~7CFU/g干土。土壤中可培养真菌数量的排列顺序为：烟草-玉米轮作烟草-百合轮作烟草连作烟草-萝卜轮作。(2)连作年限对土壤中可培养细菌和真菌数量也有显著影响。可培养细菌的数量随着连作年限的增加而减少,土壤中可培养真菌的数量与可培养细菌数的变化趋势正好相反,即随着连作年限的增加,可培养真菌数量相应增加。(3)绿肥还田对土壤可培养细菌和真菌数量也有明显影响,烟-稻-黑麦草、烟-稻-豌豆、烟-稻-满园花的可培养细菌数量均高于连作烟田的可培养细菌数量。可培养真菌数量的变化趋势(由高至低)与可培养细菌数量的变化趋势相反。
[Abstract]:Continuous cropping obstacle is called tobacco continuous cropping obstacle in tobacco. After tobacco cropping, it will appear the phenomenon of slow growth, short plant, low yield and low quality, and serious soil-borne diseases and insect pests. At present, tobacco cultivation in China also has a large area of continuous cropping. The direct and indirect economic losses caused by the continuous cropping obstacle crisis are as high as 4 billion yuan per year. It is of great economic and social significance for the development of tobacco industry in China and the whole world to strengthen the research on the mechanism of tobacco continuous cropping in order to reduce and avoid the losses caused by continuous cropping. In this study, the tobacco soil of three tobacco regions in Xiangxi Autonomous Prefecture of Hunan Province was used as the research object, and high throughput sequencing method was used to analyze different successive cropping years. Diversity and community structure of rhizosphere fungi in tobacco field soil under three tillage systems of different rotation and different kinds of green manure; The culturable rhizosphere bacteria and fungi in soil samples were isolated and counted by selective culture medium to study the changes of rhizosphere microbial communities in different regions and different incidence degree of tobacco. The results showed that under different tillage systems, the microbial diversity and homogeneity of rhizome diseases in the four groups were significantly decreased at one time. The diversity and average of tobacco continuous cropping and tobacco maize rotation were higher than that of tobacco lily rotation and tobacco radish rotation at one time. For 4 and 12 years of continuous cropping, the winter free period was higher than the onset peak period, and the diversity and average of the onset peak period in all treatments were lower than that of the winter idle period at one time, and increased with the increase of the continuous cropping years. 3) different kinds of green manure were returned to the field. The species number in the peak period was lower than that in the winter idle period. The diversity and the average value of rhizosphere fungi community in the pea field were higher than that in the winter idle period, and the diversity and the average value of the other three groups were higher than those in the winter idle period. The diversity and homogeneity of microorganism was the highest in the control group, and the lowest in the green manure group. The results of in vitro culture of culturable fungi and bacteria in the rhizosphere of different treatments showed that rotation could significantly affect the number of culturable bacteria and fungi in soil. The number of culturable bacteria in tobacco-maize rotation soil was the highest, reaching 9.38 脳 10~7CFU/g dry soil, followed by continuous cropping and tobacco-maize rotation, and tobacco radish rotation with a minimum amount of 1.15 脳 10~7CFU/g dry soil. The order of the number of culturable fungi in soil was as follows: tobacco-maize rotation tobacco-radish rotation. 2) the number of culturable bacteria and fungi in soil was also significantly affected by the continuous cropping years. The number of culturable bacteria decreased with the increase of continuous cropping years, and the number of culturable fungi in soil was opposite to that of culturable bacteria, that is, with the increase of continuous cropping years, The number of culturable fungi increased correspondingly. (3) Green manure returning to the field also had a significant effect on the number of culturable bacteria and fungi in soil, tobacco rice ryegrass, tobacco rice pea, The number of culturable bacteria in the flower of tobacco-rice-Manchurian garden was higher than that in the field of continuous cropping. The change trend of the number of culturable fungi (from high to low) was opposite to that of culturable bacteria.
【学位授予单位】：湖南农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S572;S154.3

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