Physiological And Anatomical Characteristics Of Salt-Tolerant Crossostephium Chinensis And Salt Tolerance Gene Excavation

China has about 11.8 million hm2 saline soil,saline land construction is imminent.Crossostephium chinensis is an excellent salt tolerant germplasm,and studying its salt tolerance mechanism is of great significance to the improvement of salt tolerance of ground-cover chysanthemum and the enrichment of garden plants for saline land greening.However,there are few reports on the mechanism of salt tolerance in it.In this study,we used C.chinensis and four kinds of chrysanthemum,Chrysanthemum morifolium'Fanhuasijin',C.morifolium 'Hanluhong',C.indicum(Tiantangzhai)and C.indicum(Shennongjia)as experimental materials.And the changes of anatomical structure of them under salt stress were observed by paraffin section method,and the changes of physiological indexes were measured at the same time.The physiological and physiological characteristics were studied in order to explore the unique salt tolerance mechanism of C.chinensis under salt stress.In addition,the WRKY gene,which was the most significant difference under salt stress,was screened from the data of transcripts before and after the administration of Hibiscus amurensis.The expression of WRKY gene was verified by fluorescence quantitative PCR.Then,by using quantitative PCR The expression patterns of several key WRKY genes in Fructus Glomerata and two non-salt-tolerant plants were obtained by cloning Cc WRKY3,Cc WRKY70 and CcWRKYl7,which play an important role in response to salt stress of C.chinensis.The main results are as follows:1.The anatomical structure of roots,stems and leaves of C.chinensis and four species were studied under salt stress.The results showed that compared with the other four species,the fence tissue ratio,stem bark/stem radius The increase of the ratio of column to root is the response to salt stress,and the developed vascular tissue in stem and root is one of the important reasons for its salt tolerance.2.Compared with the other four species,the activities of C.chinensis were compared with those of the other four species,and the chlorophyll content was stable and higher under salt stress Horizontal net photosynthetic rate.It can regulate the cell osmotic balance,the effective removal of reactive oxygen species,the membrane system to maintain a relatively stable.And it is the reason why its salt tolerance is stronger than other chrysanthemums species.3.The WRKY gene,which was the most significant expression of 8 salt stress before and after salt stress,was screened according to the transcript data of Oh,3h and 9h under the stress of C.chinensis,and the results were compared with those of transcriptome.The expression of 6 genes was consistent with the expression of transcriptional sequencing.The expression of these six genes was further quantified by the expression of these six genes in the genus C.chinensis and the non-salt-tolerant C.indicum(Tiantangzhai)and C.indicum(Shennongjia).The results showed that the six WRKY genes The expression patterns of C.chinensis were different from those of the other two species,suggesting that it might play a role in responding to salt stress.4.The homology analysis,conserved motif analysis and phylogenetic tree analysis of the WRKY gene were carried out.The results showed that the CcWRKY70 and CcWRKY17 genes were the most homologous and closely related to chrysanthemum,Arabidopsis thaliana or other species of the WRKY genes are involved in salt stress response,play a role in regulating the salt tolerance of plants.Therefore,we speculate that CcWRKY70 and CcWRKY17 play an important role in the process of response to salt stress.In this study,the physiological anatomical characteristics of salt tolerance were studied,and the mechanism of salt tolerance was studied.A key transcription factor,WKKY gene,which responded to salt stress in C.chinensis was excavated,laying the foundation for cultivation of salt-tolerant ground-cover chrysanthemum.