Group Differentiation Studies Of Opisthopappus Shih

Opisthopappus Shih,belonging to the family Asteraceae,includes two species,Opisthopappus longilobus Shih and Opisthopappus taihangensis?Ling?C.Shih.The micro-morphological characteristics of Opisthopappus Shih leaves were observed using scanning electron microscopy in this study.In addition,the reasons for the morphological differences were explored among the two species?O.taihangensis and O.longilobus?of Opisthopappus.The results showed that there were differences in glandular hair morphology and density,stoma size and density,anticlinal wall pattern,wax morphology,and salt vesicle size and density between O.taihangensis and O.longilobus,which resulted from the micro-environment heterogeneity of different species or different populations.The stomas and salt vesicle could be considered as important parameters for the classification of Opisthopappus.The correlation analysis indicated that there was a significant relationship between the morphological characteristics and longitude and latitude.The principal component analysisrevealed that the highest contribution rate originated from the density of glandular hairs.All 13 populations of Opisthopappus were grouped into two clusters based on the micro-structural characteristics of leaves.Three populations of O.longilobus were not grouped into a single cluster,whereas they were grouped with different populations of O.taihangensis.Historical events such as the uplift of mountains and climatic oscillations in the quaternary periods greatly affected the evolution and modern distribution of the flora.Molecular techniques using cpDNA sequenced the pet L-psbE,rp S12-rp L20,rpL32-F-trnL,rp S16×trn K,trn Q-rp S16×1 and the single copy of nuclear gene of AdF F1-R1 for the differentiation of Opisthopappus.A high genetic diversity was observed in O.taihangensis and O.longilobus(h_cpDNA=0.967,?_cpDNA= 0.30107;h^<sub>nDNA= 0.942,?^<sub>nDNA= 0.01389),especially in the GS?h = 0.63564,? = 0.04656?,WML?h = 0.94521,? = 0.04925?and BXT(h_cpDNA= 0.66667,?_cpDNA= 0.04990;h^<sub>nDNA= 0.31158,?^<sub>nDNA=0.02251)populations.AMOVA analysis revealed that 64.52% of genetic diversity was based on cpDNA,and most of the inheritable variation existed among the populations(?_{STO.taihangensis}= 65.58%,O.longilobus is 63.21%);based on nDNA,the total variation was 69.89%,whereas most of the inheritable variation existed among the populations(?_{STO.taihangensis}= 68.24%,O.longilobus 63.23%).NSTcpDNA?0.87941?> GSTcpDNA?0.64741?and N_STnDNA?0.89741?> GSTnDNA?0.64874?,suggesting a significant phylogeographic structure.The neutrality tests revealed that Opisthopappus has certainly undergone expansion events in the historical evolutionary process.According to the characteristics of the sequence,we detectedthe kind of haplotypes as 42?cpDNA?and 12?n DNA?.Most of the ancestral haplotypes?H2,Hn3?in O.taihangensis were WML,XYG,BJY,FXF,WWS,WML,XYG,GS,BJY,YTS and WWS,and the number of haplotypes was also more.In O.longilobus,the ancestral haplotypes existed only in BXT and SHS.The result showed that O.taihangensis and O.longilobus differentiation occurred at approximately 1.26 Ma,approximately at the early Pleistocene.O.taihangensis underwent an evolutionarily historical process of long-distance dispersal and colonisation,whereas O.longilobus underwent a population expansion before the primary uplift of Taihang Mountains.During the quaternary glacial periods,Opisthopappus existed in multiple shelters in the area?GS,WML,BXT?.The physiographic complexity and paleovegetation transition of Taihang Mountains primarily shaped the specific formation and affected the present distribution of these two species.