Diversity Of Blueberry Mycorrhizal Fungi In Guizhou And Their Effects On The Growth Of Blueberry Seedling

The blueberry(Vaccinium)root system does not have root hairs,and forms mycorrhiza in the natural habitat to help it absorb water and nutrients.It is of great significance to conduct in-depth research on blueberry mycorrhizal fungi and promote the application and development of mycorrhiza on blueberries.In this paper,the isolation,identification and diversity of endophytic fungi in the roots of artificially cultivated blueberries in Guizhou and parts of Sichuan were studied.Several suitable blueberry mycorrhizal fungi were screened out through back-joining verification,and the effects of these mycorrhizal fungi on the growth of blueberries were preliminarily analyzed.Through the above research,we hope to provide a basis for the development and utilization of blueberry mycorrhizal fungi to promote the growth and development of blueberries.The main results are as follows:Healthy blueberry root tissues of Majiang,Huaxi,Fenggang,Huangping,Tianzhu counties(districts)in Guizhou and Pengzhou,Ya’an and Meishan in Sichuan were Collected for the isolation and identification of endophytic fungi.From 135 blueberry root samples,a total of 1766 endophytic fungi were isolated and identified,belonging to 4 phyla and 45 genera.It Included Ascomycota,Zygomycetes,Basidiomycota,Oomycota,of which Ascomycota was the dominant phylum,including 1602 strains(IR=89%;IF=90.71%);Chaetomium spp.was the dominant genus,with 273 strains isolated(IR=15.17%;IF=15.46%),followed by Fusarium spp.,267 strains were isolated(IR=14.83%;IF=15.12%).(2)By comparing the reported mycorrhizal species of rhododendrons from1766 endophytic fungi,a total of 26 endophytic fungi that can be easily cultured and have a high isolation frequency were selected for re-inoculation test.Mycorrhizal infestation was observed after 15 d for further identification of mycorrhizal fungi in blueberries.At last,9 treatments numbered Y-037,Y-005,X-065,Y-007,Y-078,Y-017,Y-026,Y-079,and Y-012 were confirmed to have infestations with roots.The fungi at the treatments were tentatively identified as mycorrhizal fungi.Specifically,the 9 mycorrhizal fungi include Cladosporium sp.,Whalleya microplaca,Phialocephala fortinii,Acephala sp.,Rhizopycnis vagum,Helotiales sp.,Phialocephala bamuru,Cladosporium cladosporioides and Oidiodendron citrinum.(3)The biological characteristics of the 9 identified mycorrhizal fungi showed that different strains have great differences in adaptability to temperature.Among them,strain Y-005 grows fastest in the temperature range of 20-25°C,while other strains have The test strain grows fastest at 25-30℃.The tested strains have a wide range of p H adaptation.Under different p H treatments,most strains have little difference in growth,but when p H=4,the tested strains have a significantly lower diameter than other p H treatments.In addition,except for strains Y-037,Y-012 and Y-026 that grow faster when glucose was the carbon source,the other tested strains grow fastest and grow better in an environment with maltose and galactose as carbon sources,but each The tested strains showed slow growth with mannitol and fructose as carbon sources.The tested strains grow faster when yeast powder and peptone were used as organic nitrogen sources;while different mycorrhizal strains grow slowly when using ammonium sulfate,ammonium nitrate,and potassium nitrate as inorganic nitrogen sources,especially some strains Growth was inhibited under ammonium nitrate conditions.(4)Nine mycorrhizal strains were tied back to the roots of blueberry seedlings to verify their effects on the growth of blueberry seedlings.The results showed that mycorrhizal bacteria can significantly promote the growth of seedlings compared with the control treatment,especially under the treatment of strains Y-079,Y-037,Y-005,Y-026,Y-017 and Y-012.Compared with the control,the height of blueberry seedlings increased by 85.93%,77.25%,76.31%,75.37%,68.62%,and 45.69%,and the ground diameter increased by 78.57%,69.29%,67.14%,50.71%,41.42%,51.42%,respectively.Compared to control,root length and surface area werw more than 200%.The average diameter increased by 25.40%,41.27%,15.90%,26.98%,25.40% and 33.33%respectively.The number of root tips was 1.80 times,2.38 times,2.39 times,1.93 times and 1.53 times of the control,except that the Y-026 treatment was less than the control.To sum up,Guizhou blueberry root system mycorrhizal fungi resources are rich,the diversity is high,the species composition is obviously different,and most of the tested strains can effectively promote the growth of blueberries.This thesis lays a foundation for studying the diversity and biological characteristics of Guizhou blueberry mycorrhizal fungi and the application and further research of mycorrhizal fungi on blueberries.