| The ancient camphor forest in Niutian Town,Le ’an County,Jiangxi Province is a famous scenic spot for the protection of ancient camphor trees in China.There are more than10,000 camphor trees in the area,including 4127 ancient trees aged 100-1200 years.The growth of these ancient camphor trees is closely related to their root soil health and tree resistance.In order to reveal the secret of the healthy growth of ancient camphor forest in Le’an,this thesis systematically studied the diversity of rhizosphere soil fungi and the diversity of endophytic fungi in the roots of ancient camphor forest.1.Endophytic fungi were isolated from the fibrous roots of C.camphora by tissue isolation method and dilution plate method,respectively.Soil fungi were isolated from rhizosphere soil and non-rhizosphere soil of C.camphora.A total of 452 root endophytic fungi and 408 soil fungi were obtained.By morphological observation and r DNA sequence analysis,a total of 9 classes,22 orders,30 families and 33 genera of fungi were identified.Among the 860 isolates,Fusarium(12.44%),Trichoderma(10.58%),Penicillium(8.83%)and Aspergillus(8.13%)were the dominant genera.The number of fungal species isolated from camphor roots,rhizosphere soil and non-rhizosphere soil in 2021 was higher than that in2022,which may be related to the less rainfall and hot climate in 2022.Through the statistical analysis of fungi in roots,rhizosphere soil and non-rhizosphere soil of C.camphora at different ages,it was found that the fungal diversity index of roots,rhizosphere soil and non-rhizosphere soil of C.camphora at 200 a was the highest,which was 3.21,2.68 and 2.62,respectively.It was found that the fungal structure and composition of root,rhizosphere and non-rhizosphere soil of ancient camphor were similar among different tree ages.The similarity index of 800 a and 1000 a was the highest,which was 86.5%,87.7% and 89.1%,respectively.2.The diversity of fungi in rhizosphere soil and non-rhizosphere soil of C.camphora was analyzed by high-throughput sequencing technology.It was found that the main fungal groups were Ascomycota and Basidiomycota,and the dominant fungal genera were Fusarium and Mortierella.Through high-throughput sequencing analysis of endophytic fungi in the roots of 800-year-old ancient camphor trees,it was found that the endophytic fungi in the roots of camphor were mainly unidentified＿chaetosphariales＿sp.,Ilyonectria,Penicillium and Gliocladiopsis.Compared with non-rhizosphere soil fungi,the abundance of Ascomycota and Mortierella in ancient camphor root soil fungi was higher.Through the comparative analysis of the composition of fungal communities in the rhizosphere soil of ancient camphor trees of different ages,it was found that the diversity and richness of fungal communities in the rhizosphere soil of ancient camphor trees were relatively stable,indicating that ancient camphor trees formed relatively stable and specific dominant fungal groups in the rhizosphere soil during long-term growth and development.3.The mineralization characteristics of 101 strains of fungi isolated from the roots and rhizosphere soil of ancient C.camphora were analyzed by transparent circle method and colorimetric quantitative method.It was found that the strains with potassium-solubilizing,phosphorus-solubilizing,siderophore-producing and IAA-producing accounted for 40.74%,51.85%,29.63% and 81.48% of the total number of tests,respectively.It shows that the fungi of C.camphora and rhizosphere soil contain very rich beneficial fungal resources,which provide continuous mineral nutrition for the growth and development of C.camphora,so that the ancient C.camphora forest in Jiangxi Province has maintained healthy growth and development for more than one thousand years.In particular,Talaromyces haitouensis A1、A3 and Xylaria sp.B3 were found to have four growth-promoting characteristics,including potassium solubilization,phosphorus solubilization,siderophore production and IAA production,showing good growth-promoting ability.4.The antagonistic effects of 101 strains of fungi isolated from the root and rhizosphere soil of Cinnamomum camphora on plant pathogenic fungi such as Alternaria tenuissmia and Fusarium oxysporum were determined by dual culture method.Fusarium equiseti E1,Trichoderma harzianum E2,T.viride F1 and Pencillium glaucoroseum F2 were found to have good antibacterial effects.Through the determination of the bacteriostatic effect of the fermentation filtrate of the above four fungi,it was found that T.harzianum E2 had the most significant inhibitory effect on the three tested plant pathogens,among which the inhibition rate against Alternaria tenuissmia was as high as 74.75%,while the inhibition rate against the other two pathogens was about 65%.Based on the study of the diversity of fungi in the root and rhizosphere soil of ancient camphor forest in Niutian Town,Le ’an County,Jiangxi Province,the species and distribution of fungi in the soil ecological environment of ancient camphor forest were clarified,and the important role of fungal biodiversity in the healthy growth and development of ancient camphor forest for thousands of years was revealed.In addition,the fungi with inhibitory activity against plant pathogens were preliminarily screened from these living strains,which provided living strain resources for the development and utilization of fungi in the root and rhizosphere soil of ancient camphor forest. |
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