棉花根际亲和性高效促生细菌的分离筛选

Isolation and Screening of Effective and Affinity Strains of Growth-Promoting Bacteria from Cotton Rhizosphere

摘要:

为了从棉花根际土壤筛选能与棉花凝集素具有亲和作用的高效促生细菌, 以选择性培养基从棉花根部初步筛选具有固氮能力、解磷能力及解钾能力的促生细菌, 再以异硫氰酸磺(FITC)标记的棉花凝集素为复筛工具, 从棉花根际促生细菌中筛选能与棉花凝集素结合的亲和性菌株, 分别挑选2株固氮菌、2株解磷细菌和2株解钾细菌作为微生物肥料接种到棉花根部进行盆栽试验, 观察其在根部定殖情况。结果是在选择性平板上有20%~30%的菌株具有凝集素染色阳性。盆栽试验显示, 接种的6株亲和性菌株能在棉花根部成功定殖, 根际细菌数量约是灭活对照的10倍。通过初步鉴定, 固氮菌株N1111为固氮菌属(Azotobacter), N2121属于德克斯氏菌属(Derxia); 解磷菌株P2126属于黄单胞菌属(Xanthomonas), P1108菌株为假单胞菌属(Pseudomonas); 解钾菌株K2204和K2116属于芽孢杆菌属(Bacillus)。

Abstract:

To screen effective and affinity plant growth-promoting rhizobacteria strains (PGPR) that can react with cotton lectin from cotton rhizosphere, we isolate nitrogen-fixation bacteria, phosphate-releasing bacteria and potassium-releasing bacteria from cotton rhizosphere by Ashby medium, phosphate-releasing bacteria medium and potassium-releasing bacteria medium, respectively. The strains were re-screened by cotton lectin labeled with fluorescein isothiocyanate. According to their ability of nitrogen-fixation, p-releasing and K-releasing in pure culture condition, 2 strains of nitrogen-fixation bacteria, 2 strains of phosphate–releasing bacteria and 2 strains of potassium-releasing bacteria were inoculated as microbial fertilizers in pot experiment of cotton, respectively. About 20%~30% strains of PGPR had positive reaction with cotton lectin labeled by FITC among the PGPR. Study showed that the numbers of PGPR in cotton rhizosphere were about 10 times of those of controls sterilized. Pot test data suggested the 6 strains have certain affinity with cotton and can propagate in cotton rhizosphere. Through preliminary identification of 6 affinity strains, the strain of N1111 was identified as Azotobacter and N2121 was classified as Derxia. P2126 and P1108 were Xanthomonas and Pseudomonas, respectively. K2204 and K2116 were Bacillus.