Molecular Phylogeny And Morphological Evolution Of Plagiomnium In China

Bryophyte is a kind of higher plant from aquatic to terrestrial.It is one of the pioneers in the plant community.The bryophytes belonging to the genus Plagiomnium belong to the family Mniaceae and are mainly distributed in the tropical and subtropical regions of East Asia,common mosses in mountain area of china.The genus Plagiomnium is a high-class group of Acrocarpous Mosses,but some species of trophic organisms have a side-to-side pedestal type of life,which is a special group that transitions from Acrocarpous Mosses to Pleudocarpous Mosses.At present,there is still controversy over the relationship between the genus Plagiomnium and other genus and on the subgroup study under the genus Plagiomnium.Studying the molecular phylogeny and morphological evolution of this genus has important scientific significance for the exploration of the relationship of the genus Plagiomnium and other taxonomic groups under the Mniaceae,and the evolution of moss adaptation.This study,combined with morphological taxonomy and molecular methods,explored the evolution of molecular phylogeny and morphological characteristics of the Chinese genus Plagiomnium.Morphological study: The leaves of 17 species of the genus Plagiomnium were sealed in water and placed under a microscope.The morphological description and mapping of the genus were performed;the morphological coding of the 58 traits of the family Plagiomnium was performed under the principal component analysis and cluster analysis methods,numerical classification of the Chinese genus Plagiomnium is studied.Molecular studies: Select the three chloroplast DNA fragments of atp B-rbc L,matk and ycf1 and the nuclear gene fragments ITS1 and ITS2,and construct a Bayesian molecular phylogenetic tree using a single gene and multiple gene combination analysis method.Mesquite software was used in combination with morphological data to reconstruct the ancestral species of the Mniaceae species.The main findings are as follows:(1)By observing,recording and measuring the specimens of the Mniaceae bryophytes and combining literature data,58 morphological indicators with classification significance were screened out.(2)Drawing and morphological description of 17 species of Plagiomnium moss in China,and combining the morphological characteristics and molecular clustering results of the genus Plagiomnium,the species retrieval table of moss was compiled.(3)The key traits of the Mniaceae bryophytes include: vegetative shoot growth pattern,maximum leaf position in the shoot,whether the leaf base is deferred,leaf aspect ratio,leaf tip apex angle,whether the leaf ribs are close to the middle ribs,and whether they are false The color of the root,the length of the basal cells,whether the leaf cells are transparent to the middle ribs,the shape of the leaves,whether or not the middle ribs are on the top,the growth pattern of the sporophytes,and the 13 traits of the leaf length.The key traits of the genus Plagiomnium are: leaf density,length of leaf margins,leaf width,whether the leaf base is deferred,leaf cell size,maximum blade position in the stem,leaf aspect ratio,tip angle,leaf shape,leaf Whether there is luster,whether the middle ribs are topped,the growth pattern of sporophytes,the shape of leaf cells,the number of sawtooth cells,and the length of pods 15 traits.(4)In combination with the morphological clustering and molecular phylogenetic tree of the Mniaceae,the relationship between the genus Plagiomnium and the genus Mnium is clear,and it supports the independent status of the genus Plagiomnium,which supports Koponen’ point about the Plagiomnium.In addition,in the phylogenetic tree,all species of Plagiomnium come together,to further prove the monophyleticity of the genus Plagiomnium;the species of the genus Mnium are clustered together with the Rhizomnium Horikawae.The monophyleticity of the genus still requires further proof of the specimens of the Mniaceae.(5)Combining morphological data and molecular data,17 species of the genus Plagiomnium from China were grouped under the following four groups:(1)Sectio Plagiomnium: P.venustum、P.drummondii、P.cuspidatum、P.acutum.(2)Sectio Undulata: P.arbusculum、P.confertidens.(3)Sectio Rostrata: P.maximoviczii、P.japonicum、P.succulentum、P.integrum.(4)Sectio Rosulata: P.ellipticium、P.tezukae、P.medium、P.rostratum、P.rhy nchophorum、P.elimbatum.(6)The reconstruction of the ancestral state of the 5 characters of the plants of the Mniaceae(especially the genus Plagiomnium)showed that the species character evolution changed.The leaf shape evolves from the lanceolate to the oval,and the vegetative branches evolve from erect to the creeping branch;the size of the cells evolves from small to large.During the evolution of the middle ribs,it has not only the phenomenon of top but also the phenomenon of the tip of the leaf.The leaf edge saw has been changed in the process of the evolution of the sphagnfamily,and some species have a long sharp saw.Teeth,part of the species with obtuse or all margin.Under the influence of the environment,the morphological evolution of the species of Mniaceae bryophytes,and the study of its evolution process will also promote the understanding of the transformation of moss species and ecological adaptation strategies.