【摘要】 【目的】本研究旨在从石板菜（Sedum emarginatum）中分离和鉴定内生固氮菌，并探究其促生特性，以期为生物肥料和绿色生态农业的开发提供新的资源。【方法】以石板菜内生细菌为材料，通过乙炔还原法测定固氮酶活性，利用IS-PCR指纹图谱聚类、16S rRNA基因系统发育分析和理化性质鉴定等方法，对内生固氮菌进行分离和鉴定。此外，通过盆栽测试，评估了分离得到的菌株对玉米幼苗生长的影响。【结果】从石板菜中成功分离出20株内生固氮菌株，这些菌株分属于5个类群，包括Klebsiella pneumoniaesubsp.ozaenae、Proteus mirabilis、Providencia rettgeri、Klebsiella quasipneumoniaesubsp.quasipneumoniae和Phytobacter diazotrophicus。其中，K.pneumoniaesubsp.ozaenae和P.diazotrophicus不仅具有固氮能力，还具备溶磷解钾、产铁载体和产生长素等多种促生特性。盆栽测试显示，JSR1、JSR21能显著促进玉米幼苗生长。JSR21处理的玉米幼苗最长根长较对照提高48.4%,JSR1对玉米幼苗地上部生长的促进作用较对照提高27.2%。【结论】石板菜内生固氮菌种类丰富，还具备多种促生特性。这些菌株在绿色生态农业和生物肥料开发方面具有潜在的应用价值。更多还原

【Abstract】 【 Objective】 This study aimed to isolate and identify endophytic nitrogen fixing bacteria fromSedum emarginatumand explore their growth promoting characteristics, providing new resources for the development of biofertilizers and green ecological agriculture．【Method】 Endophytic bacteria fromS.emarginatumwere used as materials. The nitrogenase activity was determined by acetylene reduction assay, and the endophytic nitrogen fixing bacteria were isolated and identified by IS-PCR fingerprint clustering, 16S rRNA gene phylogenetic analysis, and physicochemical property identification. Additionally,the effect of the isolated strains on the growth of maize seedlings was evaluated through pot tests．【Result】A total of 20 endophytic nitrogen fixing bacterial strains were successfully isolated fromS.emarginatum,belonging to five taxonomic groups, includingKlebsiella pneumoniaesubsp.ozaenae,Proteus mirabilis,Providencia rettgeri,Klebsiella quasipneumoniaesubsp.quasipneumoniae, andPhytobacter diazotrophicus.Among them,K.pneumoniaesubsp.ozaenaeandP.diazotrophicuspossessed not only nitrogen fixing ability but also multiple growth promoting characteristics such as phosphorus solubilization, potassium dissolution, siderophore production, and auxin production. Pot tests showed that JSR1 and JSR21 could significantly promote the growth of maize seedlings. The longest root length of maize seedlings treated with JSR21 increased by 48.4% compared with the control, while JSR1 increased the shoot growth of maize seedlings by 27.2% compared with the control．【Conclusion】The endophytic nitrogen fixing bacteria inS.emarginatumare diverse and possess multiple growth promoting characteristics, making them potentially valuable for applications in the development of green ecological agriculture and biofertilizer.更多还原