Effects Of Ginsenoside On Soil Microbial Communities And Plant Pathogens And Pests

Ginsenoside is the main secondary metabolism product of ginseng and American ginseng, and it is also an active ingredient of pharmacological. As precious medicinal herbs, it has made a great progress of study on their pharmacological effects. However, for the exploration of their biological significance is rarely reported, it must be made in order to make better adapt to the environment and to protect their own, which is the real purpose of researching ginseng and American ginseng synthetic and accumulation of ginsenosides. In order to make a further discuss of the ecological significance of ginsenosides during growth and development process of ginseng and American ginseng, the paper focuses on the relationship between the ginsenosides and some biological factors in the environment. We studied the metabolic activity of soil microbial communities in the new forest soil after added the ginsenosides by the Biolog-ECO method, and researched the biological activity of ginsenosides on four common plant pathogens (Cercosporella brassicae、Alternaria solani、Sclerotinia sclerotiorum、Fusarium moniliforme) by testing the colony growth and conidia germination rates, at last we preliminary explored the impact of feeding and growth of three Lepidoptera (Bombyx mori, Pieris rapae,Malacosoma neustria testacea) that deal with ginsenosides.1The effects of total ginsenosides on the metabolic activity of soil microbial communities in the new forest soilAfter adding total ginsenoside10days, compared with the control, the metabolic activity of soil microbial community in new forest soil which processed by different concentrations (1.0mg/mL,0.1mg/mL, O.Olmg/mL) are significant enhanced, the community diversity index changes significantly, which the middle concentration (O.lmg/mL) treatment is the most obvious; it is ginsenoside that performs a significant promoting on soil microbial communities.After adding different concentrations of total ginsenoside for20days, the role in promoting was weakened for the metabolic activity of soil microbial community which was treated by middle concentration (O.lmg/mL), while high concentration (1.0mg/mL) and low concentration (0.01mg/mL) was significantly inhibited. The changes of diversity index suggest that the composition and structure of soil microbial community were changed. Some ingredients of total ginsenoside which could inhibit the growth of soil microorganisms also play a role.30days after the treatment, the metabolic activity of soil microbial communities between the different concentrations did not differ significantly. Compared with the control, it showed neither obvious promotion nor inhibition. Changes of community diversity become consistently. The effects of total ginsenoside on soil microbial communities are not obvious. After adding total ginsenoside40days, the metabolic activity of soil microbial community was the strongest which processed by low concentration (O.Olmg/mL), the high concentration and the middle concentration as followed, the control group shows minimum activity. The diversity index of microbial community also showed a similar law. The total ginsenoside performs simulative effect on soil microbial community.We speculated it was the total ginsenoside that changed the composition and population structure of the soil microbial community in new forest soil, and sustained directional selected pressure on the microbial community, resulting in the gradual simplification of their metabolic type.2The effects of total ginsenosides, panaxadiol ginsenosides, panaxatriol ginsenosides on four plant pathogensThe effects of total ginsenosides, panaxadiol ginsenosides and panaxatriol ginsenosides on Cercosporella brassicae, Alternaria solani and Sclerotinia sclerotiorum are roughly the same. At the early stage (24h), they had the growth and promotion effects, however, as the time went by, inhibitory effects become bigger and bigger with the concentration increasing. Inhibitory effects were significant with high concentrations, while low concentrations had no obvious effects.The growth of Fusarium moniliforme was inhibited in the first stage (24h) of culture, whose reaction to concentrations of ginsenoside is slightly different from pathogenic bacteria mentioned above. As time passed, the inhibition of colony growth gradually enhanced, which behaved concentration-related. High concentration had the highest inhibition rate.The effects of total ginsenosides, panaxadiol ginsenosides and panaxatriol ginsenosides on the conidia germination of four plant pathogens are roughly the same. The low concentrations of ginsenoside are promoting while the effects of high concentrations are suppression.3The effects of total ginsenosides on feeding and growth of three LepidopteraTotal ginsenoside had obviously inhibitory effects on hatching of Bombyx mori eggs. And the higher the concentration is, the bigger the inhibition is. Antifeedant effect of total ginsenoside on the2nd-instar larvae of Bombyx mori (selective and nonselective) was significantly correlated with the concentration. The antifeedant strength are as follows:20mg/mL>10mg/mL>5mg/mL; The rates of antifeedant reduced gradually with the processing time increasing. In addition, ginsenosides could significantly delay the growth and development of Bombyx mori, extending the stage of larval about5-13days and changing their bodies’color, which result in chronic toxic effects.The results of antifeedant of total ginsenoside on the3rd-instar larvae of Pieris rapae(L.)(Selective and nonselective) are similar to the2nd-instar larvae of Bombyx mori, but the overall antifeedant rate is slightly lower than Bombyx mori. The repellent tests outdoor suggested that the total ginsenoside can significantly affect the oviposition of Pieris rapae(L.), forcing the larval of Pieris rapae(L.) to escape from cabbage leaves that had been treated by ginsenoside.The reaction for antifeedant (selective and nonselective) of total ginsenosides on3rd-instar larvae of Malacosoma neustria testacea Motschulsky are similar to Bombyx mori, Pieris rapae(L.), but the overall antifeedant rate is lower than both, which suggested the tolerance of Malacosoma neustria testacea Motschulsky was better than Bombyx mori and Pieris rapae(L).After adult eclosion which fed with total ginsenosides, their wings were so incomplete that they couldn’t fly like others.