Effects of bio-organic fertilizer on the community structure of culturable bacteria in the rhizosphere soil of a continuous-cropping banana filed | 物有机肥对连作香蕉根际土壤可培养细菌区系的影响

Chinese. 采用可培养平板计数方法和PCR-DGGE技术,以施用生物有机肥（BIO）健康（BIOH）、发病（BIOW）和未施用BIO健康（CKH）、发病（CKW）4个处理的根际土壤为供试样品,研究可培养芽孢杆菌、假单胞菌、自生固氮菌、氨化细菌、亚硝化细菌、反硝化细菌的数量变化,以及可培养细菌的EP指数差异和细菌的群落结构变化。结果表明：施用BIO能显著增加健康植株根际土壤中芽孢杆菌、假单胞菌、自生固氮菌、氨化细菌、亚硝化细菌的数量,并减少根际土壤中的反硝化细菌数量（P〈0.05）;不同根际土壤样品的快速生长细菌和慢速生长细菌在群体中所占比例有明显差异,快速生长细菌分别占群体总数的40.9%（BIOW）、50.7%（CKW）、20.6%（BIOH）和22.1%（CKH）,其中BIOH处理不同生长速率细菌分布最均匀,EP指数值最高,为0.794;DGGE条带回收测序结果表明,BIOH处理中多样性较高,其优势菌群为厚壁菌门（Firmicutes）和变形菌门（Proteobacte-ria）,而CKW处理中的优势菌群大部分都属于拟杆菌门（Bacteroidetes）。结论：健康根际土壤的可培养细菌区系显著不同于发病根际土壤,通过外源有益生物与有机载体同时导入土壤,有可能达到调控植物根际土壤微生物区系的目的。

English. In this study,cultural dependent plate-counting and PCR-DGGE methods were used to investigate the bacterial community structure influenced by bio-organic fertilizer（BIO）.Four rhizosphere soil samples collected from healthy（BIOH）,diseased（BIOW）banana plants with BIO application and healthy（CKH）,diseased（CKW）banana plants without BIO application,respectively,were used in this study.The numbers of Bacillus,Pseudomonas,diazotroph,ammonibacteria,Nitrosomonas,and denitrifying bacteria in these samples were detected,and EP index and community structure of viable bacteria were also analyzed.The results showed that the numbers of Bacillus,Pseudomonas,diazotroph,ammonibacteria,and Nitrosomonas of BIOH treatment were significantly higher than that of other three treatment（BIOW,CKW,and CKW）,while the number of denitrifying bacteria was reduced.The rates of fast growing bacteria and slow growing bacteria were significantly different in these four samples,with the ratios of 40.9%（BIOW）,50.7%（CKW）,20.6%（BIOH）,and 22.1%（CKH）,respectively.The bacteria of different growth rates distributed most evenly in BIOH treatment,with the highest EP index of 0.794.The sequencing of the bands screwed from DGGE showed that the bacterial diversity of BIOH treatment was higher than that of the other three treatment.The dominant flora of BIOH treatment was Firmicutes and Proteobacteria,while the dominant flora of CKW treatment was Bacteroidetes.In conclusion,the community structure of culturable bacterial in healthy rhizosphere soil was significantly different from in the diseased rhizosphere soil,and the purpose of rhizosphere microflora regulation might be achieved through beneficial organisms and organic carrier simultaneously supplemented into the soil.