摘要
【目的】筛选高效固氮芽孢杆菌,研究固氮微生物固氮酶活性、竞争适应能力与接种固氮效能的关系,探讨接种固氮芽孢杆菌对根际细菌多样性的影响。【方法】采用无氮培养基富集、加热筛选固氮芽孢杆菌。乙炔还原法测定固氮酶活性,采用盆栽小白菜选育高效固氮芽孢杆菌、研究菌种竞争适应能力与接种固氮效能。通过形态、生理生化特征和16S rDNA序列分析鉴定菌种。【结果】筛选到了3株固氮酶活性相对较高、固氮能力较强的菌株GD062、GD082和GD282,初步鉴定为芽孢杆菌Bacillus spp.和类芽孢杆菌Paenibacillus sp.。进一步的研究结果表明菌株GD082竞争适应能力较强,在盆栽试验自然土壤条件下接种固氮效能与施用化肥试验处理效果相当,可望进一步研发用于生产固氮微生物肥料。试验结果同时显示,供试菌株的固氮酶活性与其接种固氮效能并不直接相关,菌株的竞争适应能力对接种固氮效能影响很大,接种固氮芽孢杆菌使小白菜根际土壤细菌多样性显著增加。【结论】接种固氮微生物为农作物提供氮素养分具有生产实践意义。高效固氮菌种的筛选是一个复杂的过程,菌株的固氮酶活性与其接种固氮效能并不直接相关,竞争适应能力对接种固氮效能影响很大。筛选到的芽孢杆菌GD082固氮酶活性较高、固氮能力较强、竞争适应能力很强,可望进一步研发成为优良的固氮微生物肥料生产用菌种。
[Objective] Efficient nitrogen-fixing bacilli were isolated, and the relationships between microbial nitrogenase activity, competition ability and inoculation effect were investigated. The influence of inoculating nitrogen-fixing bacillus on the bacterial community in crop rhizosphere was explored. [Method] Nitrogen-free medium was used to isolate nitrogen-fixers and heat treatment was used for the nitrogen-fixing bacilli. Nitrogenase activity was determined with acetylene reduction assay. Microbial competition ability and inoculation effect were tested with pot culture in greenhouse. Strain identification was carded out based on the morphology, physiology, biochemical test and 16S rDNA sequences analysis. [ Result] Three strains termed as GD062, GD082 and GD282 with relative high nitrogenase activity and strong nitrogen-fixing ability were isolated, which were identified as Bacillus spp. and Paenibacillus sp. respectively. Further result showed that strain GD082 have strong competition ability, produced an inoculation effect as well as the chemical fertilizer treatment did in the natural soil. Result also indicated that no correspondence between nitrogenase activity and inoculation effect was found. Strain competition ability influences the inoculation effect. Rhizosphere bacterial community increased significantly with the inoculation of nitrogen-fixing bacilli. [Conclusion] It is meaningful in agricultural practice to offer crop nitrogen nutrient through inoculation of nitrogen-fixers. Selection of efficient nitrogen fixer is a complexed process. There is no correspondence between nitrogenase activity and inoculation effect. Strain competition ability influences the inoculation effect even stronger. A nitrogen-fixing bacillus GD082 with high nitrogenase activity,strong nitrogen-fixing ability and competition ability was obtained, which is possible to be further developed as an excellent strain used in the microbial fertilizer production.
出处
《中国农业科学》
CAS
CSCD
北大核心
2009年第6期2043-2051,共9页
Scientia Agricultura Sinica
基金
农业部"948"项目(2007-Z1)
国家"863"项目(2006AA10Z417)
国家自然科技资源平台项目(2005DKA21201-14-1)
关键词
生物固氮
芽孢杆菌
菌种筛选
微生物肥料
biological nitrogen fixation
bacillus
strain selection
microbial fertilizer
作者简介
孙建光（1963-），男，河北邯郸人，副研究员，博士，研究方向为作物根际微生物、固氮微生物资源与微生物肥料。Tel：010-82108701；E-mail：jgsun@caas．ac．cn
