Research On Embryo Develepment And Seed Dormancy Of Heracleum Moellendorffii Hance

As an important non-wood forest product,Heracleum moellendorffii Hance is famous with special nutritional value,which acts a very vital role in the development and utilization of forest resources in northern China.In order to make the breeding of wild herbs more efficient,the research of domestication and cultivation toils a lot of efforts.At present,there are some physical and biochemical activities related to seed dormancy,embryo development of Heracleum moellendorffii Hance.The embryo development of the seed was not complete when the seed matured,and the ripening phenomenon directly restricted the large-scale cultivation.We have found that there are few studies on embryo development in living plants of the wild herbs.We think that the challenge of maximizing embryo development in living plants dealt with in a prudent way can conduce to solve the problem of seed dormancy,therefore,the artificial cultivation of the herb can provide the most convenient production guidance.The purpose of the research was to observe and analyze the stages of embryo development in the living plants of wild Heracleum moellendorffii Hance.The stage and residence time of embryo stop development were determined by microscopic observation of paraffin section,and the basic metabolism and physiological activity are analyzed in order to reach the stage of seed maturation in living plant.The embryo can reach the ideal state of maturity.It can save more time,improve germination rate and provide theoretical basis for artificial cultivation,furthermore,it will offer important scientific and technological underpinner for the breeding and popularization of wild herbs.In addition,with the development of molecular biology research,the previous research on model plants,such as Arabidopsis thaliana and other data analysis and comparison of the related issues have been further studied.As such,we make the first attempt to obtain the gene transcriptional information of the seeds of Heracleum moellendorffii Hance at different cultivation periods by high-throughout sequencing technique,and take use of a new generation of gene sequencing expression profiling analysis method.The study will screen the differentially expressed genes during the development of the embryo,and we have a good command of the changes of the gene expression in the embryo of Heracleum moellendorffii Hance,identify the key factors affecting the post-maturation of the embryo of Heracleum moellendorffii Hance,and provide the theoretical basis for its developmental mechanism from the perspective of molecular mechanism.Plant regulation and embryo development mechanism of Heracleum moellendorffii Hance were taken as the focus of the study.The embryo development of Heracleum moellendorffii Hance in stratification was studied as an auxiliary study.The whole process of embryo development was compared with the microscopic observation of paraffin section.In order to provide theoretical basis for artificial cultivation and sustainable development of wild resources,this manuscript puts forward creative research on embryo development law from a few angles,finally solves dormancy problem,and combines with suitable environmental conditions for plant growth so as to provide a theoretical basis for artificial cultivation and sustainable development and utilization of wild resources.The conclusions are as follows:(1)Under the influence of the biological characteristics of wild resources,there is still incomplete development of seed embryo in the seed maturation of Heracleum moellendorffii Hance.The embryo of natural shedding stagnates partly in the heart-shaped embryo period and partly in the torpedo embryo stage,which belongs to the phenomenon of differentiation and inconsistency.(2)The compound application of diammonium phosphate(4.07-8.14kg/667m~2)and potassium sulfate(12.00-18.00kg/667m~2)was conducive to the accumulation of saponins,coumarins and flavonoids in the leaves of Heracleum moellendorffii Hance.The plant height,stem diameter and development degree could reach the maximum under the compound application of diammonium phosphate 8.14kg/667m~2 and potassium sulfate 12kg/667m~2,and the yield of Heracleum moellendorffii Hance can be increased significantly at the same time.(3)Using RNA-Seq,we identified the DEGs in seeds between the different treatments.Using the comparison analysis between groups,we identified genes related to embryo development.In the GO terms,12 key genes were identified including CYP,MYB,APX1,GRX,HSP,LEGA,LEGB,RFC1,HOX,PAP,MPA,and FATB.(4)The GO results revealed that up-regulated proteins in H.moellendorffii were largely associated with nutrient reservoir activity,which included mainly seed-storage proteins.In addition,flower thinning also induced the changes of oxidoreductase activity.The KEGG results indicated that flower thinning can promote the degradation of fatty acids,according to the up-regulated DEGs that were significantly associated with fatty acids and the fatty acid degradation pathway,of which ACSL,ACOX1,ECHS1,and HADH were all up-regulated after flower thinning.(5)The change of temperature stratification can effectively promote the after-ripening of embryo,shorten the time of seed dormancy,and is beneficial to release the dormancy.The incidence of cotyledon embryos under the treatment of changing temperature stratification was up to 87.25%,and the embryo rate was also the maximum among the groups,and the germination rate of Heracleum moellendorffii Hance seeds was increased effectively by changing the temperature stratification,which was significantly higher than that of low temperature stratification during stratification period,meaning that the highest germination rate registered 43%.