川西北高寒草甸植物根际促生菌筛选及其特性研究

Screening and Characteristics of Plant Growth-Promoting Rhizobacteria From Alpine Meadow Plants in Northwestern Sichuan

为获得多功能的高寒植物根际促生菌(Plant growth-promoting rhizobacteria,PGPR),并明确其生理生化特性,本研究采用选择性培养基法从川西北广泛分布的5种高寒草甸植物根际土壤和根系中分离了44株菌株,并对菌株的溶磷、固氮和解钾特性进行测定。结果显示:25株为溶无机磷菌株,24株为溶有机磷菌株,溶磷量分别在10.98~90.27μg·mL^(-1)和10.58~64.56μg·mL^(-1)之间;固氮菌株共20株,其固氮酶活性介于5.23~64.87 nmol(C2H4)·h^(-1)·mL^(-1)之间;解钾菌株21株,解钾量在9.23~73.21μg·mL^(-1)之间。经过形态学和生理生化特征分析,最终筛选出12株兼具溶磷、固氮和解钾的多功能菌株,分子鉴定将其归属于不动杆菌属(Acinetobacter)、沙雷氏菌属(Serratia)、假单胞菌属(Pseudomoas)、芽孢杆菌属(Bacillus)、戴尔福特菌属(Delftia)和寡养单胞菌属(Stenotrophomonas)。研究结果可为川西北高原土壤微生物菌肥的开发提供优质菌源参考。

The study aimed to obtain multi-functional plant growth promoting rhizobacteria(PGPR)and clarify theirphysiological and biochemical characteristics,including nitrogenfixation,phosphorusand potassium solubilization,rhizosphere soil and roots from five widely distributed alpine meadow plants were used to isolate the bacterial strains,and a total of 44 strains were obtained.The results showed that 25 strains were inorganic-phosphorus-dissolving ones and 24 strains were organic-phosphorus-dissolving ones,the capacities of phosphorus-dissolving for these two strain types were 10.98~90.27μg·mL^(-1) and 10.58~64.56μg·mL^(-1),respectively;Additionally,20 strains were able to fix nitrogen biologically nitrogenase activity:5.23~64.87 nmol(C2H4)·h^(-1)·mL^(-1) and 21 strains were able to release potassium(potassium releasing capacity:9.23~73.21μg·mL^(-1)).On basis of morphological,physiological and biochemical characteristics,12 strains with multiple functions(phosphorus-solubilizing,nitrogen-fixing and potassium-releasing)were finally screened out.These 12 strains were identified as Acinetobacter,Serratia,Pseudomoas,Bacillus,Delftia and Stenotrophomonas with molecular method.The study provides a good reference for developing high quality soil microbial fertilizers in the northwestern Sichuan Plateau.