Even For Thirty-seven Soil From Toxic Substances

Notoginseng is the root of Panax notoginseng(Burk.) F.H.Chen which belongs to the family Araliaceae.It's Chinese herbal name is Sanqi which has effects of hemostasis and promoting blood flow,such as shortenning coagulation time, invigorating blood circulation,antithrombus,detumescence and analgesis.In recent years,social demand in Notoginseng is steadily rising while new applications are developed.However,there was some abstacle in continuous cropping,which had an adverse effect on utilization of local land in Yunnan had seriously hampered local economic development.Autotoxicity is deemed to be one of main factors for abstacles,but autotoxicity and self-allelochemicals of Notoginseng has not been reported.Therefore,the purpose of this study is to validate the autotoxicity potential in continuous cropping soil of Notoginseng.Notoginseng seedlings and continuous cropping soil were conducted as the subjects and materials respectively.The allelochemicals could be analysisd on the basis of confirmation about autotoxicity. Autotoxicity of the chemicals could be identified in further.The dose-effect relationship woule be verificated.This study may provide a way to reduce abstacle in continuous cropping and provide a theoretical basis for decrement.The major findings are as follows:(1) According to the survey we found that continuous cropping have an adverse effect on the normal growth of Notoginseng.The incidence of root rot had been decreased along with the increasing of rotation years.The incidence of ten years' rotation soil closed to the normal level basicly.The seedling height and carex height of Notoginseng which was cultivated in three years' continuous cropping and one year's unused soil was significantly lower than the normal cultivated soil. Mortality rates of Notoginseng Seedling which was cultivated in one year's and two years' continuous cropping soil with the pot was higher than the normal level, 75%and 100%respectively. (2) Toxicity evaluation system of notoginseng was set up.Autotoxicity of continuous cropping soil with notoginseng was confirmed by the germination experiment and seedling growth experiment.The germination rate,germination index,root length, seedling height,fresh weight and NR activity of Notoginseng seedling was inhibited by aquatic extract from Notoginseng continuous cropping soil at 1.0g/ml. Furthermore,seedling height and germination rate was lower than aquatic extract from uncultivated soil 28%and 4.44%respectively.Germination rate and root length of Radish was lower than aquatic extract from uncultivated soil 14%and 23%respectively.(3) The toxicity of different polar extract of root-zone soil was estimated by measuring the effects on growth of Notoginseng.Results indicated that ethyl acetate extraction produce a strong inhibitory effect.Ethyl acetate extracts at 0.01mg/ml from root-zone:soil is more toxic to seedling growth than other concentration.Seedling height was lower than the control at 46%.(4) HPLC fingerprint of ethyl acetate layer of extract from root-zone soil was set up. Notoginsenoside-G which was included in ethyl acetate layer was speculated by HPLC-MS analysis.(5) A triterpenoid saponin(Ginsenoside-Rh₁) subsequently identified from the toxic ethyl acetate extracts.The constituent and structure was identified by means of TLC,NMR and HPLC-MS analyses,respectively.This compound had a high inhibitory activity on Notoginseng growth.Its inhibition thresholds were 1.57×10^-7～1.57×10^-6mol/L.It had a strongest inhibition at 1.57×10^-7mol/L while seedling height was decresed at 59%.Furthermore,this compound was detected both from root of Notoginseng and root-zone soil.(6) Dynamic changes of chemical constituent in continuous cropping soil are analysesed.HPLC fingerprint of extract from diffreent year cropping soil has a same chromatogram peak.In this paper,the characteristics and innovation in the following aspects:(1) The results suggest that abstacle in continuous cropping of Notoginseng should be related to autotoxicity. (2) Autotoxicity of continuous cropping soil with Notoginseng was confirmed. Also,the mode and the role of the extent of autotoxicity were inspected. Moreover,the dose-effect relationship of Autotoxicity was finded.(3) Research method of Self-allelochemicals which was identified partly in Notoginseng was set up.Furthermore,the toxicity of Self-allelochemicals was verificated by bioassay.