Study On Allelochemicals And Allelopathic Mechanism Of Artemisia Annua.L.

Allelopathy,Allelochemicals and Allelopathic Mechanism of Artemisia annua.L. were studied in this paper.In order to use the Allelopathy of plant to control the weeds in agriculture, exploit the new natural herbicide, utilize natural resources more effectively and sensibly, and to develop sustained agriculture theory. The results as follows:1. The allelopathic effect of 18 kinds of plants in the Gansu province were researched on wheat,cucumber and radish.The results showed that agueous extract of the aerial part of Artemisia annua L had the highest allelopathy on three receptor plants.The inhibition Synthesis effect of cucumber, wheat and radish were 33.09%,57.5% and 81.6% respectively. The lower inhibition effect showed on Xanthium sibiricum Patrin.,Portulaca oleraca L.,Cephalanoplos segetum Kitam,Chenopodium album L.,Tribulus terrestris L.,Amaranthus retroflexus L. Agueous extract of the aerial part of Artemisia annua L also had high allelopathy on receptor seed of Taraxacum officnala, Artemisia annua L., Avena fata.,radish,cucumber, and wheat. The inhibition Synthesis effect of cucumber, wheat and radish were higher. The inhibition Synthesis effect of wheat , Avena fata.and radish were 66.29%,67.17% and 62.55% respectively;The study on inhibition effect of aqueous extract of different part of Artemisia annua L.showed that the most allelopathic effect came from the stem and leaf of Artemisia annua L.2.Using silica gel column chromatography Isolated and purified the extract of Artemisia annua L . The solvent methanol showed higher inhibition activity and ratio of extract. Assemble normal hexane:aether had the better ability of eluting. The first separation got 32 fractions, the secondary separation got 51 fractions.The Allelochemical were sieved and traced by bioactivity on receptor wheat.After isolating and purifing , two substances with different polarity were identified by GC-MS.One substance was 3-desoxy-Deoxydihydro qinghaosu,the molecular formula was C15H22O4.The other substance was (3,8,8-Trimethy-1,2,3,4,5,6,7,8-octahydro-2-naphthalenyl) methyl acetate,the molecular formula was C16H26O2.3. Agueous extract of the aerial part of Artemisia annua L. had obvious effect on cell membrane permeability of receptor.Agueous extract led to the extracellular osmose fluided and enhanced the conduction value .The root morphology deformed, the growth of root was inhibited and the number of root hair was declined.The cell in growing point of root tip deformed, growth rate of root tip was slow down. Atypic nucleolus , indistinct cytoderm profile, fewer plasmodesmus , endoplasmic reticulumand amyloid were observed under the electron microscope. Then influenced the growth, development and split apart of the cell of root.4. Studied on the effect of extract of Artemisia annua L. on the enzymes in the receptor Arena fata with different concentration between 12h and 60h. The results indicated that the activity of polyphenoloxidase (PPOD), the hyperoxide mutase (SOD), the peroxide enzyme (POD) and the catalase (CAT) were inhabited by allelochemicals of Artemisia annua L .The activity of PAL was increased. The variation of enzymes cut down the resistance and inhabite the growth of receptor plant.The allelopathic effect was observed.