Allelopathic Effect Of Ginseng Root Exudates On Ginseng

Ginseng (Panax ginseng C. A. Meyer) is a perennial herb of Araliaceae family. In ginseng cultivation, there is a agrotechnical problem world-wide that is the replant failure of ginseng. Currently ginseng is mainly cultivated in forestry lands, hence, large forestry area have been cut to grow ginseng. It is causing soil and water losses, mountain landslide and a whole series of problems. The paper reviewes the development and progress of studies on the production of ginseng and research of allelopathy of ginseng and American ginseng. Recent researches have shown that the replant failure of ginseng is linked to allelopathy. The mechanism of the replant failure of ginseng is investigated from a chemical ecology viewpoint. Ginseng root exudates were extracted and identified. We investigated the allelopathic effects of ginseng root exudates on seed germination and biomass of ginseng and american ginseng. The effects of ginseng root exudates on the activities of antioxidant enzymes in ginseng.Adopted complex sterile matrix substrate to cultivate ginseng, ginseng root exudates were collected in situ. The ginseng root exudates were extracted with water and ethanol, the composition were divided into the petroleum ether extracts and the ethyl acetate extracts two parts. Each part was identified by GC-MS analysis. Results showed that the petroleum ether extraction is consisted of 1,3-dioxolane,4-ethyl, 4-methyl-2-pentadecyl,ethyl citrate,pentacosane and some other chemicals. The ethyl acetate extracts is made up of butyl citrate,dibutyl phthalate,1,2-benzenedicarboxylic acid,mono(2-ethylhexyl)ester and ect. In the petroleum ether extraction, hydrocarbons take a proportion of 54.984%, acids 17.362%, and esters 20.708%, along with benzenes 1.554% and pyrans 5.393%. In the ethyl acetate extracts, hydrocarbons take a proportion of 14.080%, alcohols 8.687%, acids 26.582% and esters 50.649%. Trace amounts of ginsenosides were detected in ginseng root exudates.adopted complex sterile matrix substrate to cultivate ginseng, ginseng root exudates were collected in situ. The extraction of ginseng root exudates with water and MeOH, divided into the aqueous phase and the ethyl acetate phase two parts with ethyl acetate extract.The design of different concentrations, researched on the four kinds of medicinal plants on seed germination and hypocotyl, fresh weight of allelopathy indoor cultivation. Results showed that ginseng root exudates on seeds allelopathy of four kinds of medicinal plant had a difference. The Rhubarb and Silybum marianum Gaertn.seed germination had the varying degree inhibitory action, decreased seed a-amylase activity.The fresh weight and hypocotyls of Rhubarb dropped to a level lower than the control when treated by high treatement concentrations while increased at low to medium treatment concentration. The fresh weight and hypocotyls of Silybum marianum Gaertn. increased with aqueous phase while dropped to a level lower than the control with ethyl acetate phase. the Burdock seed germination and seed a-amylase activity increased at low to medium concentrations of aqueous phase phase while decreased at high concentrations of aqueous phase. The Burdock seed germination and seed a-amylase activity decreased with ethyl acetate phase.Ginseng root exudates's aqueous phase promoted hypocotyl elongation while ethyl acetate phase inhibited hypocotyl elongation, with to the Burdock fresh weight's influence is consistent. At medium to high concentrations inhibited the germination of Melilotus albus Desr. While promoted their germination at low concentrations with aqueous phase of ginseng root exudates.At medium to high concentrations promoted seed germination of Melilotus albus Desr. While inhibited the seed germination at low concentrations with aqueous phase of ginseng root exudates.This is is consistent basically with the seed's a-amylase activity. Ginseng root exudates inhibited hypocotyl elongation and fresh weight of Melilotus albus Desr. Conclusion:Ginseng root exudates on four kinds of medicinal plants had different degree allelopathy effects. the close relationship existed bewteen allelopathy and the content of allelochemicals.We investigated the allelopathic effects of ginseng root exudates on seed germination and biomass of ginseng and american ginseng. Ginseng was cultivated in a sterilized composite substrate. Root exudates were collected in-situ and then successively extracted with water and methanol. The two eluates were combined and partitioned with ethyl acetate. The water and ethyl acetate extract were recovered and assayed. Root exudates exhibited a stronger allelopathic effect on ginseng than on american ginseng. Water-extract was the most inhibitory on seed germination and a-amylase activity of both ginseng and american ginseng. Root exudates inhibited the radical elongation of ginseng and american ginseng, with ethyl acetate extract showing the strongest allelopathic effects. The inhibitory effects were concentration dependent. Ginseng root exudates exhibited varying effects on hypocotyl of ginseng and american ginseng. All extracts from root exudates of ginseng inhibited the fresh and dry weight of ginseng and american ginseng.With root exudates treatment, a large amount of superoxide anion were produced in ginseng seedlings.SOD activity was significantly inhibited. Ginseng root exudates had little effect on the activity of POD and CAT, All ginseng root exudate treatments were accompanied by an increased Malondialdehyde (MDA) content and decreased root activity.