Releasing Mode And Isolated And Identified Of Main Allelochemicals From Artemisia Annua. L

The allelopathy widely existed in the nature and played a vital role in the reasonable arrangement of crop cultivation system, controlling of farmland weeds,preventing crops from disease and insect infection as well as reducing the barrier harm of the succession cultivation. Preliminary studies confirmed allelopathy and allelopathic mechianism of Artemisia annua L.. Under the nature conditions, the allelochemicals releasing mode of Artemisia annua L.. have been studied in this paper. Subsequently, main allelochemicals of volatile way and extracts were isolated and identificated. The purpose of the research was to provide a theoretical basis for developing the new biological herbicide and plant growth regulator, reasonably and effectively utilizing natural resources, as well as developing sustainable agriculture by using the allelochemicals. The main results were showed as follows:1.Regarding Artemisia annua L. as donor plant and wheat, oats, cucumber and radish as receptor plants allelochemicals releasing mode of A. annua L. were studied , by adopting indoor bioassay. The results showed that aqueous extract, volatile matter, eluviate matter, residues and root exudates five allelochemicals of A. annua L. had different degrees of allelopathy to four receptor plants. The inhibition synthesis effect(SE) for aqueous extract of A. annua L. were 56.29 and 57.17 to wheat and oats. The volatile matter of the aerial part of A. annua L. had evident inhibition effects on roots length of four receptor plants.The eluviate matter had inhibite wheat and cucumber growth, however, the eluviate matter had promote effects on oats and radish. The residues in recent 10 days had the evident inhibition effects on receptor plants. The root exudates had strongly inhibite wheat and oats, but it had promote effects on cucumber and radish. In comparison to SE of five different allelochemicals , we can see the allelochemicals of A. annua L. mainly released volatile matter and eluviate matter to the environment, secondly, the allelochemicals released root exudates to the environment.2. In this study, the allelopathy of Artemisia annua L. volatile oil was examined,and its chemical constituents were analyzed by GC/MS . The results showed that the volatiles released from leaves and stems of Artemisia annua L. significantly inhibited the seedling growth of wheat,oats and radish. Volatile oil obtained from the volatile oil extractor of fresh leaves and stems also significantly inhibited the seedling growth of wheat,oats and radish,the allelopathy effect index (RI) were below -0.50.56 volatile components in the volatile oil were identified.The main chemical components were Camphor , Eudesma-4(14),11-diene , Caryophyllene ,Cadindiene,Caryophyllene oxide,Linaloone,α-Cadinenol and Eucalptol. The relative content were23.212%,15.633%,7.054%,6.83%,6.489%,6.349%,6.097% and 3.458%, respectively. Camphor,Eudesma-4(14),11-diene,Caryophyllene,Cadindiene and Caryophyllene oxide as allelchemicals have be reported. The reports of Linaloone and Thujopsene of the allelopathic effect were seldom.3. Allelopathic effect of aqueous extract and methanol extract were bioassayed. The results showed that methanol extract allelopathic effect was stronger than aqueous extract .When the treatment concentration was 0.1g/mL, the inhibition synthesis effect(SE) for methanol extract of A. annua L. were 68.16,61.12,46.69 and 43.98 to wheat,oats,cucumber and radish. Separated methanol extract with hexane,dichloromethane and methanol, and analyzed by GC/MS, the results indicated that the hexane fraction contained twenty-nine components and the main components were N-alkane in which Neophytadiene ,Hopene and acetic acid vitamin ester have allelopathic effects.The dichloromethane fraction contained Hexadecanoic acid methyl ester,(Deoxy)arteannuin,Ergesta-4,6-dien-3-ol(3β)and Stigmastan of the allelopathic effect have been reported.β.-Amyrin , 4,4,6a,6b,8a,11,11,14b-Octamethyl-1,4,4a,5,6,6a,6…octadecahydro-2H-pic-en-3-one , 4,4,6a,6b,8a, 11,11, 14 b-Octamethyl-1,4,4a,5,6,6a,6…,Eicosanoic acid,methyl ester and Urs-12-en-24-oic acid,3-oxo-, methyl ester of allelopathic effect was firstly reported. The dichloromethane fraction had stronger allelopathic effect on germination and seedling growth of wheat. The methanol fraction contained long-chain fatty acids mainly. Phthalate , Tetradecaoic acid , Pentadecanoic acid , Hexadecanoic acid ,Heptadecanoic acid, Octadecaricnoic acid,Arachidic acid and the allelopathic effect of other long-chain fatty acids were reported. The report about the allelopathic effect of 2-Penetadecanone,6,10,14-trimethyl,Urs-12-en-3-ol,acetate,A'-Neogammacer-22(29)-en-3-ol acetate and Benzenepropanoic acid,3,5-bi(s1,1-dimethylethyl)-4-hydroxy-,octadecyl ester was the initial time.Those indicated that allelochemicals releasing mode of Artemisia annua L. mainly were eluviation of rain and mist,volatilization in the natural condition.