ABSTRACT
Ginsenosides are the main active ingredient and allelochemicals of Panax ginseng, and they play an important role in ginseng growth and in ecological adaptation. To study the influence of ginsenosides on soil microbial communities, the method of given exogenous total ginsenosides of different concentrations were used to study the influence of ginsenosides on new forest soil microbial community, evaluate the change of metabolic activity of microbial community and investigate the ecological effect of ginsenosides on soil microbial community. Results showed that, exogenous total ginsenosides promoted metabolic activity of microbial community in new forest soil at different concentrations compared with the control after 10 d and 40 d treatment. After 10 d,except for the Evenness index, all of the other indices indicated that the functional diversity of the soil microbial community in the new forest firstly increased then decreased with increase of the total ginsenosides concentration. The Substrate richness for 0.01 g•L⁻¹ soil treatment was significantly different from that of the control. After 20 d, 30 d and 40 d, except for the Evenness index, all of the other indices indicated that the functional diversity of the soil microbial community in the new forest increased with total ginsenosides. These results suggested that ginsenosids can change soil microbial community and microbial metabolic activity, which alter soil microbial ecology and accordingly affect the growth of ginseng with accumulation of ginsenosides in the soil.
ABSTRACT
Paeonia suffruticosa also named Moutan that cultivated in five geographic regions during different growth stages were chosen in this study. Biolog and 454 pyrosequencing technology were used to detect the whole microbial activity and fungal diversity for exploring the relationship between the geo-authentic features of the medicinal plant and the rhizosphere microorganism. The results suggest that the value of average well color development (AWCD) from the rhizosphere soil of P. suffruticosa in the five regions at the fo ur growth stage have an increasing tendency. 9 703 operational taxonomic unit (OTU) were obtained from 272 463 high quality sequences according to the similarity of 97% by the pyrosequencing. Fungi in five phyla, twenty-two classes, seventy orders, one hundred and thirty-nine families and two hundred and sixty-six genera were detected in the five regions excluding twelve percent to fifty-eight percent unidentified fungi. They were divided into four branches, i.e. Blastocladiales, Chytridiomycota, Dikarya and Glomeromycetes. Twenty-four genera such as Leptosphaeria were found in the five regions while six genera such as Curvularia were only detected in the geo-authentic regions. The dominant genera were Guehomyces, Exophiala and Fusarium in geo-authentic regions, whereas genus Leptosphaeria, Cryptococcus, Exophiala, Fusarium and Ceratobasidium in non-authentic regions. The results from principal co-ordinates analysis (PCoA) showed that the fungi formations were similar in Tongling and Nanling region at four different growth stages, and the same in Heze at the leaf bud and fruiting stage. According to heatmap analysis, Tongling and Nanling region showed a close similarity in fungal community structures on phylogenetic analysis, while Bozhou, Heze and Luoyang showed the same. In brief, the whole microbial activity was higher in geo-authentic regions than the non-authentic. Fungi in rhizosphere soil of the medicinal peony presented diversity and region specificity. We found not only the abundant new species in the five regions, but also the phylogenetic similarity in the geo-authentic regions.