The relationship between shifts in the rhizosphere microbial community and root rot disease in a continuous cropping American ginseng system.

The root rot disease causes a great economic loss, and the disease severity usually increases as ginseng ages. However, it is still unclear whether the disease severity is related to changes in microorganisms during the entire growing stage of American ginseng. The present study examined the microbial community in the rhizosphere and the chemical properties of the soil in 1-4-year-old ginseng plants grown in different seasons at two different sites.

[Effect of light intensity on growth, accumulation of ginsenosides, and expression of related enzyme genes of Panax quinquefolius].

Appropriate light intensity is favorable for the photosynthesis, biomass accumulation, key enzyme activity, and secondary metabolite synthesis of medicinal plants. This study aims to explore the influence of light intensity on growth and quality of Panax quinquefolius. To be specific, sand culture experiment was carried out in a greenhouse under the light intensity of 40, 80, 120, and 160 μmol·m~(-2)·s~(-1), respectively.

Application of vermicompost and biochar suppresses Fusarium root rot of replanted American ginseng.

Soil sterilization integrated with agronomic measures is an effective method to reduce soilborne replant diseases. However, the effect of vermicompost or biochar application after soil sterilization on soilborne diseases is poorly understood. A pot experiment was conducted in American ginseng to investigate the effects of vermicompost (VF), biochar (BF), and a combination of vermicompost and biochar (VBF) applied after soil sterilization on the incidence of Fusarium root rot using natural recovery (F) as control.

First report of root rot caused by Fusarium armeniacum on American ginseng in China.

American ginseng (Panax quinquefolius) is an important medicinal plant cultivated in China since the 1980s. Its dried roots are used for food, health care products, and medicine in China (Yuan et al. 2010).

[Quality-based soil fertility quality assessment of American ginseng main production areas in Shandong province].

The soil fertility quality is one of the most critical indicators of soil productivity. It directly affects the yield, quality and agricultural efficiency of Chinese medicinal materials. In order to establish the American ginseng planting soil fertility quality evaluation method based on the effective components of American ginseng, Wendeng district, Weihai city, Shandong province, the main producing area of American ginseng, was cited as a case for the study.

[Effects of nutrients deficiency on growth and saponin accumulation of American ginseng].

Mineral nutrient elements are the key factors to maintain the growth and quality of American ginseng. In order to understand the comprehensive effect of different nutrient elements deficiency on American ginseng, 2-year-old American ginsengs were cultivated by Hoagland solution(CK) or 10 different nutrients deficiency solution in sand culture. During the cultivation, the deficient symptom was observed.

Effects of maize rotation on the physicochemical properties and microbial communities of American ginseng cultivated soil.

The production of American ginseng (Panax quinquefolius L.) is severely limited by the replant disorders in China. Crop rotation with maize might reduce the replant problems, but little information is available on the effect of maize rotation on soil cultivated with ginseng.

[Autotoxic effect of ginsenoside extrats on growth of American ginseng in different medium].

Ginsenosides are the abundant secondary metabolites in American ginseng (Panax quinquefolium), it could be released into soil through root exudation and decomposition during plant growth. This study determined ginsenoside contents in American ginseng cultivated soil by HPLC. Three ginsenosides, Rb1, Rb2 and Rd, were detected in the rhizosphere soil of 3-4 years old American ginseng cultivated in Huairou District, Beijing, and their contents were 0.

[Fungal composition in massa medicata fermentata based on culture dependent method and independent PCR-SSCP technique].

Objective: To analyze the fungal composition in Massa Medicata Fermentata based on culture dependent method and independent PCR-SSCP technique.

Method: Fungi were directly isolated from Massa Medicata Fermentata samples. The obtained strains were identified according to morphology and DNA sequence.

[Effect of continuous cropping and soil treatment on rhizosphere fungal community of Panax quinquefolium].

Objective: To analyze the effects of continuous cropping and soil treatment on rhizosphere fungal community of Panax quinquefolium, and the correlation between rhizosphere fungal community and growth of P. quinquefolium.

Method: Field plot trail of continuous cultivated P.

[Variation of ginsenosides in infected roots of American ginseng (Panax quinquefolium)].

Unlabelled: To study the infected root of Panax quinquefolium on the contents of ginsenosides.

Method: The contents of three major ginsenosides Rg1, Re and Rb1 were determined by HPLC compared quantitatively between the different degree infected roots and normal root in the phloem and xylem.

Result: Rg1 in phloem and xylem of varying degrees infected root showed no significant difference, but Rb1 decreased 26.