烤烟不同套作模式对土壤理化性质和真菌群落结构的影响

本文以烤烟套种结球甘蓝(LF)、白菜(BF)和豌豆(WF)作物之间的物质交互区域土壤(烤烟与套作作物主根间的物理对称中点0~20 cm土层土壤)为研究对象,应用ITS测序、主座标分析(PCo A)、Alpha多样性分析等方法分析土壤真菌群落结构变化及其与土壤理化特征变化之间的关系,同时结合烤烟经济性状和烟叶光合特性、SPAD值来综合分析三种套作处理的优劣。结果表明,该地区土壤中真菌的主要类群为Ascomycota(子囊菌门)、Basidiomycota(担子菌门)、Zygomycota(接合菌门)、Chytridiomycota(壶菌门)、Glomeromycota(球囊菌门)五大门类,套作甘蓝和豌豆的土壤真菌优势菌门均为Ascomycota(子囊菌门),而烤烟套种白菜的优势菌门为Basidiomycota(担子菌门),套作甘蓝的优势菌属为Coprinellus(鬼伞属)、Mortierella(被孢霉属),套作白菜的优势属为Mortierella(被孢霉属)、Lecanicillium(蜡蚧菌属),套作豌豆的优势属为Mortierella(被孢霉属)、Rhizophlyctis(囊根壶菌属);套种甘蓝和豌豆的土壤真菌群落结构较相似,两个处理土壤真菌菌属存在偏向性富集趋势,套种白菜的土壤真菌群落结构与另外两组差异较大,其土壤真菌的丰富度和多样性指数最高,且真菌菌属没有明显的偏向性富集趋势;烤烟套种白菜的土壤更适合多种真菌共同存在,互相制约,与该处理对应的烟叶产值量和光合指标也最高,烤烟套种白菜有利于改善土壤微生态环境,提高烤烟产量。相关性分析发现chao1(丰富度指数)和速效氮含量呈显著负相关关系,而与土壤p H值呈极显著正相关关系,Simpson(多样性指数)全氮含量呈显著负相关关系,土壤中氮含量过高,会显著降低真菌琢多样性指数,真菌Mortierella、Chlorophyllum是引起土壤氮含量变化的关键菌属。

Influence of Different Intercropping Patterns of Flue-cured Tobacco on Soil Properties and Fungal Community Structure

Soil samples were collected from 0 ～ 20 cm soil layers of interaction area which interplanted flue-cured tobacco with rassica oleracea L.(LF),Brassica campestris L.(BF) and Pisum sativum L.(WF).And we used TS sequencing,PCoA analysis and alpha diversity methods to analyze the change of soil fungi community construction and its relationship with soil physicochemical characteristic,and to discuss the advantage and disadvantage of 3 interplanting treatments according to economic trait,photosynthetic characters and SPAD value.The main results showed that the main soil fungi groups had 5 phyla including Ascomycota,Basidiomycota,Zygomycota,Chytridiomycota and Glomeromycota.Dominate fungi at phylum level was Ascomycota in relay intercropping of LF and WF,Basidiomycota in that of flue-cured tobacco and BF.Dominate fungi at genus level was Coprinellus and Mortierella in relay intercropping of flue-cured tobacco and LF,Mortierella and Lecanicillium in that and BF,and Mortierella and Rhizophlyctis in that and WF.The similar fungi community structure was found in relay intercropping of LF and WF,which showed directional enrichment.However,the interplant of flue-cured tobacco and BF had different fungi community structure with that and LF and WF,was with the highest relative abundance and diversity index,and showed no enrichment trend of fungi genus.The interplant of flue-cured tobacco and BF was beneficial to the coexistence and interaction of most soil fungi,got the highest yield and quality of tobacco leaves and photosynthetic indexes,improved soil micro-ecological environment and increased flue-cured tobacco yield.Chaol index had negative correlation with available nitrogen and high significant positive correlation with soil pH,and simpson index and total nitrogen showed significant negative correlation.Too high soil nitrogen content resulted in the decrease in diversity index.Mortierella and Chlorophyllum was the key genus which lead to the change in soil nitrogen content.