Isolation And Screening Of Proteobacteria Growth-promoting Bacteria From Rhizosp-here Of Angelica Sinensis And Effects Of Growth-promoting And Stress-resistant

Angelica sinensis is the dried root of Angelica sinensis（Oliv.）Diels of the Umbelliferae plant.It is a traditional Chinese medicine and has been included in the catalogue of medicinal and food homology.Gansu is an Angelica sinensis production area,and its output accounts for more than 80%of the country’s total,which plays a decisive role in the national Angelica sinensis market price.Due to the limitation of the ecological adaptation area of Angelica sinensis and the increase of planting years,the production problem of Angelica sinensis is prominent.In particular,the long-term large-scale application of chemical fertilizers has resulted in the reduction of soil microbial diversity,nutrient imbalance,poor ecosystem stability,stunted growth and development,and reduced disease resistance and stress resistance,which not only directly affects the ecological safety of authentic medicinal materials,but also affects the quality of medicinal materials.Medication safety.Plant rhizosphere growth-promoting bacteria are a class of bacteria that live in the soil or colonize the rhizosphere,root surface,root or plant stems and leaves of plants and can promote plant growth,increase crop yield,or antagonize plant pathogenic microorganisms and prevent crop diseases.microorganism.In this study,the growth-promoting bacteria were isolated from the rhizosphere soil of Angelica sinensis,the strains were identified,and the Proteobacteria strains were screened for functional characteristics detection.Under field conditions,the effects of compound inoculants on soil available nutrients,enzyme activity,plant growth,physiological characteristics,yield and efficacy of Angelica sinensis were studied.The main research results are as follows:1 20 strains were isolated from the rhizosphere growth-promoting bacteria of Angelica sinensis,7 strains were Proteobacteria strains,and 3 strains were identified as Pseudomonas,Shenella,Stenotrophomonas,Rhizobium,Sphingomonas each 1 strain.It was determined that6 strains had the ability to fix nitrogen,4 strains had the ability to dissolve phosphorus,7strains had the ability to produce ACC deaminase,and 7 strains had the ability to nitrify and produce salicylic acid,indole acetic acid,ligninase,and cellulase,laccase,chitinase,xylanase,1 strain was better at antagonizing Fusarium solani,and 2 strains were better at promoting the growth of maize seeds.2 Compared with the non-inoculated control,by Proteobacteria Pseudomonas（Pseudomonas fluorescens CBS5+Pseudomonas alcaligenes CBS7+Pseudomonas extremaustralis CBSB）and Firmicutes Bacillus（Bacillus subtilis 5C1+Bacillus amyloliquefaciens 5C5+Bacillus velezensis 5C7）two kinds of compound inoculants can promote the growth of Angelica sinensis plants,increase the biomass;increase the net photosynthetic rate,stomatal conductance,intercellular CO₂concentration,transpiration rate,and increase the peroxidation rate.Catalase,peroxidase,superoxide dismutase,polyamine oxidase,diamine oxidase and polyphenol oxidase activities,increase the levels of endogenous jasmonic acid,cytokinin and gibberellin in plants,and improve Angelica sinensis medicinal materials The content of ferulic acid,Ligustolide A,Z-ligustilide;reduce the content of malondialdehyde（membrane lipid peroxidation product）and abscisic acid（aging factor）and reduce the incidence of root rot.3 Compared with the non-inoculated control,Proteobacteria T1（Zoogloea ramigera CBS4+Pseudomonas fluorescens CBS5+Pseudomonas alcaligenes CBS7+Pseudomonas extremaustralis CBSB）and T2（Pseudomonas fluorescens CBS5+Pseudomonas alcaligenes CBS7+Pseudomonas extremaustralis CBSB）treatment significantly increased the activities of soil carbon and nitrogen catabolism-related enzymes in rhizosphere during the vigorous and late growth stages of Angelica sinensis root,and decreased the activity of alkaline phosphatase;increased soil available potassium and nitrate Nitrogen,ammonium nitrogen,available nitrogen,ammonium nitrogen,nitrate nitrogen content in roots and nitrate reductase activity;promote root growth and increase yield.Compared with T2,T1 significantly increased the activities of soil invertase and urease at the vigorous root growth stage（P<0.05）;soil ammonium nitrogen,available nitrogen and ammonium nitrogen content in roots;soil nitrate nitrogen,available nitrogen,root content at the end of growth stage Ammonium nitrogen,nitrate nitrogen content and nitrate reductase activity in roots.4 The selected Proteobacteria compound bacteria can promote the growth,photosynthesis and stress resistance of Angelica sinensis,and improve the quality of Angelica sinensis medicinal materials to different degrees.It can activate potassium in the rhizosphere soil;increase the ratio of nitrate nitrogen in the rhizosphere soil through nitrification,and alleviate the toxic effect of high concentrations of ammonium salt on root growth.Angelica sinensis can increase the ratio of nitrate nitrogen to ammonium nitrogen in roots by actively transporting nitrate nitrogen;increase the activity of nitrate reductase in roots,promote the conversion of nitrate nitrogen to ammonium nitrogen,and improve the efficiency of nitrogen absorption and utilization.Conclusion:The practicability of compound inoculants for increasing yield and quality of Angelica sinensis,and the potency of promoting growth and stress resistance were reasonably verified through field experiments;the changing laws of inoculants on soil nutrients and enzyme activities in the rhizosphere of Angelica sinensis were dynamically analyzed;From hormones,enzyme activities and nitrogen,the mechanism of bacterial agents on the growth-promoting and anti-stress effects of Angelica sinensis was preliminarily elucidated;it lays a theoretical basis and experimental basis for the application of Angelica sinensis and other root Chinese medicines to increase production and quality,promote growth and resist stress,and can also be used for the screening and excavation of excellent growth-promoting strains,compound bacterial agents development provides important reference.