This study aims to acquire the peanut root-promoting rhizobacteria(PGPR)with multifunction of fixing nitrogen,dissolving phosphorus and potassium,and synthesizing the auxin,for increasing and improving the yield and quality of peanuts in Henan. Five PGPR strains of HS4,HS7,HS9,HS10,and HS11 were screened from sandy alluvial soil of peanut rhizosphere in North China. Further HS9 was chosen by comparing various functional indexes. The activity of nitrogenase,dissolving phosphorus and potassium and IAA synthesis of HS9 were 15.53 nmol C2H4/h·mL,279.23 mg/L,and 22.5 mg/L and 40.96 mg/L,respectively. HS9 was identified as Bacillus flexus based on the morphological observation,16S rDNA gene sequence analysis accompanied with physiological and biochemical test. Pot experiment was then conducted to test and verify the effects of growth promoting,and the results showed that inoculation with HS9 significantly increased the content of available phosphorus and potassium in soil,and distinctly enhanced the content of IAA in soil. This led to the root length,surface area, root volumes and root tips of peanut increased 109.60%,84.30%,76.08% and 386.24%,respectively. It indicated that the strain promoted plant nutrient uptake and utilization,and increased plant biomass and nutrient content. The average wet weight of plants was 1.7 times higher than the control treatment and the height of peanut inoculated with HS9 significantly increased by 28.35% ;the SPAD(Soil and plant analyzer Development)value significantly increased by 16.06% and the total N,P and K content of peanut significantly increased by 23.11%、83.04%and 23.95%,respectively. Conclusively,the multifunctional strain HS9 has solid growth-promoting effect on peanut and broad agricultural application prospect.%为了获得具有固氮、解磷解钾及合成生长素的多功能花生根际促生菌(PGPR),提高和改善河南花生种植区的花生产量和品质.从华北地区花生根际砂质潮土中筛选出5株多功能促生菌HS4、HS7、HS9、HS10、HS11,通过对其各功能指标的对比挑选出菌株HS9,其固氮酶活性、解磷解钾以及产IAA能力分别达到15.53 nmol C2H4/h·mL、279.23 mg/L、22.5 mg/L和40.96 mg/L.经形态观察、生理生化指标以及16S rDNA保守序列鉴定,确定该菌株为弯曲芽胞杆菌(Bacillus flexus).最后通过花生盆栽实验验证其促生能力.盆栽实验表明:接种HS9能显著提高土壤中速效磷、钾含量,极显著地提高了土壤中IAA的含量;植株的根总长、根表面积、根体积和根尖数分别增加了109.60%、84.30%、76.08%和386.24%,促进植株对养分的吸收和利用,提高植株生物量以及养分含量;植株鲜重、株高、叶绿素值(Soil and plant analyzer development,SPAD)及氮、磷、钾含量分别提高了70.05%、28.35%、16.06%、23.11%、83.04%和23.95%.该多功能菌株对花生具有良好的促生作用,具有广阔的农业应用前景.
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