Cytological And Molecular Systematic Studies On The Genus Plagiogyria(Plagiogyriaceae)

Plagiogyriaceae is a natural monotypic fern family,containing only one genus Plagiogyria,which distributed in tropical and subtropical Asia and America disconnectedly,and the mountainous area of Southwest China is the distribution center of this genus.The up-to-date revision includes 11 species,8 from China.Although there are a few studies in palynology and chemical composition,the researches about cell taxonomy and molecular phylogeny are still limited.The number of chromosomes is still uncounted.In the aspect of molecular systematics,many studies on this genus at the level of family,so it is necessary to further clarify the relationships among species and trace the evolution of important key morphological characters.In this research,we sample 115 individuals of 9 species at the level of populations,and report the chromosome number,meiosis process and reproductive mode of Plagiogyria in the aspect of cell taxonomy.Meanwhile,We combin the three chloroplast DNA fragments(rps4-trnS,trnL-F,rbcL-atpB)and a nuclear gene(gapCp)fragment to reconstruct the phylogenetic relationships among the species,it is discussed that the ancestral state and evolution of key morphological traits.The main results shows:1.studies on cell taxonomyPlagiogyria adnata(Blume)Beddome n=66,Plagiogyria stenoptera(Hance)Diels n=66,Plagiogyria falcata Copeland n=62(3111+31 1),Plagiogyria assurgens Christ n=66,Plagiogyria pycnophylla(Kunze)Mettenius n=66,Plagiogyria glauca(Blu Me)Mettenius n=66,Plagiogyria japonica n=66 and Plagiogyria euphlebia Mettenius n=66.The P.falcata,P.pycnophylla and P.assurgens chromosome number were reported as the first time,and the number of chromosomes of the other 5 species is a new cell type.Although the spores number of P.falcata is 64,during meiosis of I,the chromosome pairing behavior of the microspore mother cells display hybrid triploid.Other spore mother cells paire normally during meiosis,it is identified as sexual diploid.Genus Plagiogyria has three kinds of chromosome number x=66,62,65,according to quantity and distribution of the different chromosome number,confirm that its the original base is x=66,and x=62,65 is the secondary base.Chromosome occur Ploidy and aneuploid variation,the trend of chromosome number evolution is decreased variability.2.Molecular Systematics research1)The interspecific relationship of genus Plagiogyria can be summarized as P.pycnophylla,P.glauca and P.assurgens cluster into one branch,while P.adnata,P.japonica and P.euphlebia cluster into one branch,all the P.falcata cluster together,all the P.stenoptera cluster together.2)The sample 03-006 of Guangxi Daming mountain is considered to be P.falcata,but the molecular evidence indicates that it is associated with P.adnata,so it may be P.adnata;The samples of 09-015 and 09-021 in Japan may be hybrids,and their male parent is P.adnata,at the same time the morphological evidence suggests that P.japonica and P.euphlebia are female parent;P.adnata of Guangxi Lianhua mountain may be the intermediate type of P.euphlebia and P.adnata;P.japonica of Sichuan Jinfo mountain and P.adnata cluster together,it is Middle type of P.adnata and P.japonica in pinna split,for the top and the lateral pinnae 1-2 pairs of P.japonica of Sichuan Jinfo mountain connect;molecular evidence support highly the sample P.sp(10-001)of Vietnam and P.japonica in guangdong shaoguan are sister,we speculate that P.sp is P.japonica.3)The sample of 05-007 in Yunnan Cangshan is considered to be P.pycnophylla,but molecular evidence suggests that it might be P.glauca,However,the leaf color of the 05-007 sample,which tends to gray and white,is similar to P.glauca in the external morphology.The samples P.sp(10-016)and P.sp(10-019)of Philippines in molecular evidence shows that it is a member of P.glauca,suggesting that these species may be P.glauca.4)There is a close relationship between P.matsumureana and P.adnata.3.morphological evolutionIn order to study the ancestral state and evolutionary history of the key morphological characters of each species in the genus Plagiogyria.By using the method of maximum parsimony,we reconstruct the ancestral state of 6 species of the genus Plagiogyria,The result show:The "plumose fracture" is the original state in the leaves of the sterile leaf type,After the"pinnation" evolve independently twice,crossing evolution;the "keratin" is the original state of the leaf type,and the"herbaceous" evolve independently at least three times;the "triangle and circle triangle" are the original state in cross section of the petiole,the "ellipse","triangle" and"triangle" cross evolution,"trapezoid" evolve independently once,"square" independent evolve three times;the "V shape" of the vascular bundle is a primitive state,and the "U" and "three"shapes evolve independently 3 times and once;the ancestral state whose growing way of the pinna base is uncertainty,while these two characters of the "with rachis adhesion" and "base cuneate,rounded orflat" are evolving at least 3 and 4 times independent evolution,with crossing evolution;the "green" is the original state in the color of leaf back,and the "gray" character evolve at least three times,and it also shows that may be the phenomenon of crossing evolution,related to its growth environment and elevation.