[Effects of growth years of Paeonia lactiflora on bacterial community in rhizosphere soil and paeoniflorin content].

ABSTRACT

To explore the relationship between microecological environment and Paeonia lactiflora the effects of growth years of P. lactillora on rhizosphere bacterial communities were studied by PCR-DGGE and the paeoniflorin content determined by HPLC. Results showed that the soil pH increased with growing years of P. lactillora. In the fourth year, soil pH and enzyme activity reached the highest level, while organic matter content was the lowest. The bacterial diversity had a positive correlation with growing years varied from 3.38 to 3.61. Sequencing results demonstrated that Gammaproteobacteria, llphaproteobacteria, Actinobacteria, Acidobacte- ria and Firmicutes were predominant bacteria kinds in the soil of P. lactillora. Gammaproteobacteria was only detected in the bulk soil, while llphaproteobacteria, Acidobacteria G1l, Actinobacteria were only in the rhizosphere soil and the bacterial community among different growing years were similar except few species. HLPC results showed that paeoniflorin content was 3.26%, 3.30%, 3.36%, 3.41% separately from one to four-year-old P. lactiflora with an upward trend. The correlation analysis indicated that the paeoniflorin content had a positive correlation with soil pH and bacterial diversity, conversely, had a negative correlation with organic matter con- tent. During the growth years the rhizosphere bacterial diversity increased without changes of predominant bacteria and the paeoniflorin content increased without significant differences while its production increased significantly, which was different from the plants showing replanting diseases. This is in line with the farming practice choosing 4-year-old P. lactllora, but not the 1-3 year old one. In addition, the accumulation of paeoniflorin is closely related to soil pH, organic matter content and bacteria diversity, confirming that the geoherblism of P. lactiflora is closely related with microbial environment in the soil.