Study On Seed Dormancy Characteristics Of Pairs Polyphylla Var.yunnanensis And The Physiological Differences Of Plants In Different Populations

Objective:Pairs polyphylla var.yunnanensis,as a valuable traditional Chinese medicine,is an important part of Yunnan Baiyao,Gongxuening and other proprietary Chinese medicines.Due to the dormancy characteristics,slow growth and increasing market demand,wild Pairs polyphylla var.yunnanensis resources have been very scarce,and artificial cultivation is the main means to solve its resource supply.In order to provide the theoretical basis for the introduction and planting of Pairs polyphylla var.yunnanensis,the photosynthetic physiology and the content of total saponins in different habitats were compared,and the micro-molecular mechanism of dormancy release during seed germination was explored.in order to provide a theoretical basis for introduction and planting and resource protection.Methods:The main results are as follows:1.The photosynthesis of Pairs polyphylla var.yunnanensis,which is in seed-setting stage in six producing areas of Lijiang City,Yunnan Province,such as Ludian Township of Lijiang City,Huaping County of Lijiang City,Yongping County of Dali Prefecture,Malong District of Qujing City,Qilin District of Qujing City and Shizong County of Qujing City,was studied by using LI-6800 optical cooperation instrument,and the photosynthetic physiological change patterns of the same varieties from different areas and different sources from different areas were detected and analyzed.2.Compared with the methods recorded in Chinese Pharmacopoeia by HPLC,the changes of saponins in the rhizomes of the same varieties from 6 different areas and different sources from the same origin were analyzed.3.Using high-throughput transcriptome sequencing technology,the transcriptome sequencing of Pairs polyphylla var.yunnanensis seeds at different germination stages was carried out by means of Illumina Hi Seq platform and RNA-seq.Results:The main results are as follows:1.The photosynthetic capacity of Pairs polyphylla var.yunnanensis in western Yunnan is higher than that in southeastern Yunnan,there is a great difference in photosynthetic capacity among different varieties in western Yunnan,and there is no significant difference in photosynthetic rate among different provenances in southeastern Yunnan.The leaf stomatal conductance（G_s）,transpiration rate（T_r）)and water use efficiency（WUE）)of Pairs polyphylla var.yunnanensis from different habitats were lower than those of local varieties,while the ratio of intercellular CO₂ concentration to environmental CO₂ concentration（C_i/C_a）was higher than that of local varieties,and the photosynthetic capacity of transplanted varieties was lower than that of local varieties.2.Among the six different producing areas,the content of saponins in the rhizome of Pairs polyphylla var.yunnanensis collected from Yongping County,Dali Prefecture is the highest,and that from Shizong County,Qujing City is the lowest.The contents of saponins in the rhizomes of Pairs polyphylla var.yunnanensis from the other four producing areas were almost the same.Among the five different varieties of Pairs polyphylla var.yunnanensis which were transplanted to Shizong County of Qujing City,the content of saponins of the local varieties not transplanted in Shizong County was the lowest.3.By means of high-throughput transcriptome sequencing,775732996 original reads numbers and 734535834 filtered high-quality reads numbers were measured.19G high quality base number.A total of 103476 genes were annotated by seven functional databases,such as NR,GO,KOG,KEGG,Swiss-Prot,Trembl,Pfam and so on.Through annotation,it was found that the similarity between Yunnan Zhonglou gene and Elaeagnus angustifolia,sea jujube and American oak was more than 10%.According to GO classification,18 cellular components,11 molecular functions and28 biological processes were obtained.According to KOG classification,it was found that there were the most genes predicting general function（2145）and the least extracellular structure genes（21）.Through software processing,a total of 35239differential genes were obtained during the four stages of seed germination.Conclusion:The results showed that the photosynthetic capacity of Pairs polyphylla var.yunnanensis in western Yunnan was stronger than that in southeastern Yunnan,especially in Yongping County,Dali Prefecture,but the photosynthetic capacity and water use efficiency of the transplanted varieties were lower than those of the local varieties.There is no significant difference in the content of saponins in the roots of Pairs polyphylla var.yunnanensis from different producing areas,and the physiological stresses caused by rainfall,temperature and light intensity have great influence on the accumulation of effective components.The varieties after transplanting will also reduce the accumulation of effective components in varying degrees because of their own adaptability.Through the high-throughput sequencing of seeds at different germination stages,several species（Elaeis guineensis,Phoenix dactylifera,Quercus suber）similar to Pairs polyphylla var.yunnanensis genes were obtained,and a variety of biological processes and their genes numbers were classified.as well as some possible key genes involved in the release of seed dormancy,which lays a foundation for the follow-up high-throughput sequencing experiment.Through high-throughput sequencing of Pairs polyphylla var.yunnanensis seeds at different germination stages,some key genes that may participate in the release of seed dormancy were discovered,such as GA₃ox,GA₂₀ox,ABI5,ABI3,etc.The content of synthetic genes that promote the germination of GA hormones is up-regulated,and the synthetic genes that inhibit the germination of ABA hormones are down-regulated.