Physiological And Biochemical Changes And Transcriptome Analysis During The Development Of Regenerated Buds Of Artemisia Frigida

Artemisia frigida is a perennial plant of Artemisia in Asteraceae.As a sign of grassland degradation,Artemisia frigida has the advantage of early regreening and can tolerate harsh climatic conditions and mechanical interference.The growth and development characteristics of Artemisia frigida buds enable it to return to green earlier than other plants,and more branches can be sprouted during the returning period.In this thesis,Artemisia frigida plants after simulated mild grazing(mowing)were used as materials to measure the number of buds,physiological indicators and endogenous hormone content at the critical stage of bud development,analyze the effects of simulated grazing(mowing)on carbohydrate accumulation,related enzyme activities and changes in endogenous hormone content,and at the same time,use molecular biological techniques to systematically reveal the molecular mechanism of Artemisia frigida bud development from the transcriptome level,and further explain the complex regulatory network of bud development process.The main results are as follows :1.After simulated grazing(cutting)treatment,the number of buds increased the fastest at 10 d,the number of buds increased to the maximum at 20 d,and the number of buds began to decrease at 40 d.Therefore,10 d,20d and 40 d were taken as the key period to study the development of Artemisia frigida buds.2.The carbohydrates that mainly provide energy for the development of Artemisia frigida buds are soluble sugar and starch,followed by protein.During bud development,the contents of soluble sugar,starch and protein increased first and then decreased.Soluble sugar reached the maximum at 10 d,and starch reached the maximum at 20 d.The two complement each other to provide energy for bud development.3.The overall activity of antioxidant enzymes was enhanced.The change trend of SOD and POD was consistent,both of which increased first and then decreased,and the ROS during the development of Artemisia frigida buds was removed together.CAT showed an upward trend but not significant,indicating that CAT response was not as significant as SOD and POD.4.During the bud development of Artemisia frigida,the GA content increased first and then decreased,which was consistent with the increase of bud number,and promoted the bud development.IAA content increased rapidly to the peak and then fluctuated slightly,which promoted bud development.ABA content decreased first and then increased,which was negatively correlated with the number of buds and inhibited the development of buds.5.Screening differentially expressed genes during the development of Artemisia frigida buds and performing functional enrichment analysis,a total of 29 differentially expressed genes related to carbohydrates were identified,and genes regulating key enzymes such as glucose-1-phosphate adenyltransferase,β-amylase,β-glucosidase were significantly differentially expressed.There were 23 differentially expressed genes related to antioxidant system,and the key genes regulating SOD,POD and CAT were significantly differentially expressed.Among the 16 differential genes related to plant hormones,the genes regulating auxin response factors,SAUR family proteins,gibberellin receptor GID1,DELLA protein,and protein phosphatase were significantly differentially expressed.