| Ginseng(Panax ginseng C.A.Mey.)is a valuable traditional Chinese medicine with high medicinal value.In recent years,the demand for ginseng in domestic and foreign markets has been high.China has always been a major supplier of ginseng in the world,accounting for twothirds of the world's ginseng production.Due to environmental requirements and the characteristics of avoiding repeated cropping of ginseng,ginseng cultivation has always been limited by land resources.The soil is the base of all terrestrial organisms,and the biological activities in the soil affect not only the soil itself but also the biological communities on the surface of the soil.Soil microorganisms are the most active ingredients in the soil ecosystem.They can improve the physical and chemical properties of the soil and regulate soil nutrition through microbial activities,directly participate in the cyclic metabolism of substances,and indirectly affect plant growth and development.The development and optimization of farmland cultivation ginseng soil improvement technology is of great significance to the development of the ginseng industry.In order to provide theoretical support for the directional improvement of soil microbial community and provide reference for guiding production,the soil characteristics,microbial diversity and community distribution were compared and analyzed,and the quality of cultivated ginseng was compared.High-throughput sequencing of rhizosphere soils of different cultivated ginsengs showed that the sequence obtained 11 215 bacterial OTUs,belonging to 48 phylums,120 classes,337 orders,605 families and 1 374 genera,7 545 fungal OTUs,belonging to 17 phyla,51 class,131 order,349 family and 861 genera.Proteobacteria and actinomycetes in the soil were dominant bacterial communities,ascomycetes and Mortierella were dominant fungal communities.The predominant flora in the ginseng rhizosphere soil was unchanged,but the relative abundance of the community would change with the growth.For example,the Fusarium and Pichia in the ginseng rhizosphere soil cultivated on the farmland during harvest were significantly higher than the flowering period.The ICP element analyzer measured the content of trace elements in the soil,the electrode method measured the soil p H,and analyzed the correlation with microbial diversity.The results showed that there were differences in the p H value and trace element content between the cultivation modes in each sample area.The difference was mainly affected by time and region.The soil treatment method had little effect on the element content,and the element content in the soil was different during harvest and flowering.The content of Ca in the rhizosphere soil of cultivated ginseng in felled area was 2 years old> 3 + 3 annual> 3 + 2 annual> CK(uncut ginseng harvested soil).And the content of Ca in CK is much lower than the area where ginseng is planted.It is known that ginseng will be sterilized with quicklime during planting,which in turn causes an increase in Ca content.The p H,Mn,Zn,and Mg element contents have a great influence on the distribution of microbial communities,and p H has a very significant correlation with various microbial communities,and is the main factor affecting the community structure and diversity.The pathogenic microorganism Fusarium had a significant negative correlation with p H,but no correlation with Ca content.The content of total polysaccharide was determined by phenol sulfuric acid method,nine kinds of saponins Rg1,Re,Rf,Ro,Rb1,Rc,Rb2,Rb3,Rd and the sum of the contents of saponins were determined by HPLC,and the volatile oil components were determined by GC-MS.The results showed that the polysaccharide content of the lower part of the ground was higher than that of the upper part.The total polysaccharide content of the lower part of 4 years ginseng in Weibaimu treated and 2 years seedlings in cottonseed treated were both higher than 19 mg/g,which was significantly more than other treatments.However,the total polysaccharide content in the two-year-old seedlings using Oka fumigation was the least,only 14.848mg/g,which was significantly lower than other treatments.There was no obvious difference in the polysaccharide content of the aboveground.Whether the total polysaccharide content of the underground part of ginseng was affected by fumigant needed further experiments to explore.The total polysaccharide content of the above-ground parts of cultivated ginseng in farmland was similar between different treatments;the Rg1,Rb1,and Re contents in different regions were significantly different.The Rb1 content in Fusong area samples was higher,and the quality of ginseng in Fusong area was better than that in Ji'an area.The components of volatile oil in cultivated farmland ginseng dry products in different regions and treatments were relatively small.Among them,ginseng alcohol was only detected in Fusong area,and the volatile oil components linoleic acid and linolenic acid in ginseng had lower content.In different treatments of ginseng dry products,a considerable amount of anti-cancer effect of erythritol was detected.Among them,2-year-old ginseng had the highest relative content of 23.16% on average.Among perennial transplanted ginseng,Fusong area averaged 16.19%,while Ji'an area averaged 15.62%,but the 5-year straight root content in Ji'an area was relatively low,only 9.55%.Different regions and treatments have no obvious effect on the composition of volatile oil.This paper compares the microbial diversity and community structure distribution of rhizosphere soil under the forest nursery ginseng,the cultivated ginseng in the harvested area and the ginseng in the farmland,and analyzed the differences in the biological level of each cultivation method,finded the respective dominant bacterial communities,provided a theoretical reference for the directed improvement of farmland ginseng,and a guidance for the reasonable cultivation of ginseng,optimized the soil improvement plan of farmland cultivated ginseng and provided a reference for determining the most suitable microbial community structure for ginseng growth. |
PDF Full Text Request