Study On The Effect Of Drought Stress On Synthesis Of Pharmacodynamic Components Of Atractylodes Chinensis And Its Regulation Mechanism

Objective:In the previous study,our group found that the quality of A.chinensis from different cultivation areas in Jilin Province was very different due to the differences in ecological environment,which greatly affected the clinical efficacy and product quality of A.chinensis.Therefore,on the basis of this study,the response laws of A.chinensis to different degrees of drought stress?light drought LS,medium drought MS and severe drought SS?were systematically studied to explore the physiological and ecological response of A.chinensis to drought stress,in order to reveal the mechanism of its water physiological and ecological adaptability,provide theoretical basis for in-depth study of the ecological mechanism of the quality formation of A.chinensis,and also provide theoretical basis for the further study of the ecological mechanism of the quality formation of A.chinensis.The standardized,refined and large-scale cultivation of A.chinensis provides reference.Method:In this study,the annual seedlings of A.chinensis were used as the experimental materials,and the greenhouse potting method was used to simulate the local natural precipitation with artificial water supply to carry out the long-term drought stress study of A.chinensis.The contents of atractylodin,atractylone and?-cineole in rhizome of A.chinensis were determined by HPLC,the photosynthetic physiological characteristics of A.chinensis were determined by photosynthetic analyzer,the anti stress physiological characteristics of A.chinensis s were determined by enzyme-linked immunosorbent assay,and the response of atractylodin,atractylone and?-cineole accumulation to drought stress was explored by real-time fluorescence quantitative PCR and enzyme-linked immunosorbent assay.The purpose of this study is to provide theoretical and scientific support for the exploration of the ecological control mechanism of the quality of A.chinensis.Result:1.The results showed that the fresh and dry weight of rhizome of A.chinensis under different drought stress treatments increased gradually during the stress period,and the drought stress treatment reached maximum value,the growth and dry matter accumulation of rhizome of A.chinensis were significantly affected at 40 days,and the fresh and dry weight of rhizome of A.chinensis under SS stress decreased by 32.03%and 28.63%respectively?P<0.05?.LS and MS stress were beneficial to the synthesis of atractylodin,atractylone and?-eucalyptol in A.chinensis,while severe drought stress inhibited the accumulation of effective components in A.chinensis.There was a significant positive correlation between dry matter accumulation and atractylodin and?-eucalyptol synthesis in rhizome of A.chinensis.In addition,the effect of drought stress on the fresh weight of rhizome of A.chinensis is greater than that on the dry weight of rhizome.2.The results showed that the net photosynthetic rate of A.chinensis under mild drought stress was not significantly decreased,but after 80 days of moderate and severe drought stress,the stomata of leaves were closed,the photosynthetic rate was significantly decreased and the transpiration was seriously hindered due to the lack of CO₂ supply,CK and LS treatment showed no significant decline in the activity of stress resistant protective enzyme,MS and SS treatment showed significant decline,and the activity of protective enzyme was negatively correlated with the content of atractylodin,and the synthesis and accumulation of atractylodin and?-eucalyptol were closely correlated with the activity of stress resistant protective enzyme;the photosynthesis of A.chinensis was blocked under drought stress,which would directly affect the accumulation of atractylone and?-eucalyptol.However,there was no significant effect on the accumulation of atractylodin.3.The formation mechanism of effective components of A.chinensis under drought stress was studied,ACC and HMGR gene expression and key enzyme activity were significantly higher than CK group?P<0.05?,and long-term severe drought stress inhibited the expression and activity of key enzyme in the biosynthesis pathway of effective components of A.chinensis;ACC was the key enzyme gene in the biosynthesis pathway of atractylon,HMGR was the key enzyme gene in the biosynthesis pathway of atractylone and?-cineole,both of which were under drought stress under different stress,it may activate the same defense system or different defense system,resulting in different expression of key enzyme genes in the synthesis pathway,thus affecting the synthesis of secondary metabolites.Conclusion:One year old A.chinensis can tolerate mild drought stress for about 60 days,and its critical point of drought is moderate drought stress?60%precipitation?,and its drought resistance ability is strong.Short-term mild and moderate drought stress is beneficial to the accumulation of dry matter and effective components of A.chinensis,and it can resist drought stress by regulating photosynthesis and anti adversity enzyme activity.Severe drought stress will not only inhibit the synthesis and accumulation of dry matter and effective components of A.chinensis,but also inhibit photosynthesis and anti adversity response of plants.The synthesis and accumulation of atractylodin,atractylone and?-cineole in A.chinensis are not controlled by a single factor,but the result of multiple factors such as photosynthetic characteristics,anti stress physiological characteristics,expression of key enzyme genes and key enzyme activity in biosynthesis of effective components.