Study On Optimization Of Tissue Culture System And Regulation Of Essential Oil Yield Of Thymus Serpyllum L.

Thymus serpyllum L., a kind of Lamiaceae, is a perennial dwarf shrub, an important medicinal plant. It is a xerophyte, which like cool climate, the sunshine; It always grow in stony mountain, sandy slopes, sand dunes and other places. Its water requirements are not high, which are resistant to drought, cold, barren. Leaves appear green or reddish purple, flowers appear purple; Corolla have glands, leaves, sepals as same, so it has a strong aroma. Thymus serpyllum L. is used as ground cover plants in landscaping projects, and also used for ornamental and aromatic lawn.Thymus plants have intense aroma, because Thymus plants are rich in essential oil. Essential oil of Thymus contains a variety of chemical constituents, and terpenes are is the main part of essential oil, which contain such as monoterpenes, sesquiterpene and diterpene; The essential oil can resist infection and eliminate inflammation, improve the digestive system, prevent and treat of gynecological diseases, promote blood circulation, strengthen the immune system, reduce pain caused by nerve function; The essential oil is widely used in the field of chemical industry, pharmacy, food processing, and has better market prospect. The market demand of essential oil of Thymus is booming. Nevertheless, there are many problems, for example: synthetic difficulty, lower rate of plant extracts, lower content of active ingredient, longer of plant growth cycle.By adjusting conditions in the medium, the objective of the experiment is to establish optimization of regeneration culture system of Thymus serpyllum L. by using the adventitious buds of Thymus serpyllum L. as material. On the basis of the optimized system, We investigate the effect of the elicitor Cu²⁺ on the proliferation and physiological aspects of Thymus serpyllum L. by adding different concentrations of elicitors Cu²⁺; while we research the effect of the elicitor Cu²⁺ on the yield and quality of essential oil, hoping to increase the content of its essential oil. The tissue culture system and elicitor adjustment system provides theoretical basis and data references for seed breeding of Thymus serpyllum L. and industrial production of essential oil.The main research results are as follows:,1,The results showd that MS+6-BA0.1mg/L+NAA0.3mg/L was suitable for inducing adventitious buds, and MS+macroelement（1MS）+ microelement（1/2MS） for propagating adventitious buds, and MS+NAA1 mg/L for inducing roots. After transplanted 30 days, the survival rate of tissue culture seedlings was 78%.2, The adventitious buds of Thymus serpyllum L. in vitro culture were treated by difference concentration of Cu²⁺; after that, we measured proliferation index of the adventitious buds. The results showed that low concentrations of Cu²⁺ can facilitate the proliferation of adventitious buds of Thymus serpyllum L., and high concentrations of Cu²⁺ inhibited the adventitious buds proliferation. Comparison of proliferation coefficient of adventitious buds: 50 μmol/L > 10 μmol/L > 0 μmol/L > 100 μmol/L > 150 μmol/L > 200μmol/L. The best concentration on adventitious bud proliferation is 50μmol/L, the proliferation coefficient was up to 20.35.3, The elicitor Cu²⁺ have a certain role in the regulation on physiological metabolism of adventitious buds of Thymus serpyllum L. Compared with the control group, the various indicators of treatment group have different degrees of increase or decreasein the growth process of adventitious bud proliferation. The change trends of soluble sugar content was “high-low-high-low”; The content of soluble protein showed a trend of first increasing and then decreasing; In different growth periods, the SOD and POD activity show different changes, which have certain differences. In the vigorous growth period of adventitious buds（Day 7-28）, a low concentration（10、50 μmol/L） of Cu²⁺ can enhance SOD and POD activity of Thymus serpyllum L. In the whole process of culture, the PAL activity of the treatment group was higher than that of the control group.4, The suitable concentration of Cu²⁺ can promote the synthesis and accumulation of essential oil of Thymus serpyllum L., while optimizing its composition. Compared with the control group, essential oil content of adventitious buds after treatment with 50μmol/L Cu²⁺ reached 0.2725%,and it is 23.98% more than the control. The color of essential oil is deeper and the contents of most esters were decreased and the contents of phenolic compounds increased. The essential oils chemotypes of Thymus serpyllum L. change from the linalool class to the carvacrol class.