Studies On Cytology And Leaf Epidermal Micro-morphology Of The Genus Ainsliaea (Asteraceae)

Ainsliaea DC.is an Asiatic genus of the tribe Mutisieae Cass in the family Asteraceae. Ranging from Afghanistan to Japan,49 species and 19 varieties are recognized,26 species are endemic to China.Ainsliaea DC.is the base group of Asteraceae,revealing the typical distribution of eastern Asia,may have played an important role in early evolvement of Asteraceae and differentiation of eastem Asia flora.The evidences based on cytology and leaf epidermal micromorphology of Ainsliaea DC. have important value in resolving its taxonomic questions(species delimination and infrageneric classification) and evolvement(if polypoidy is involvled in the speciation occurred in the Hengduan Mountains).But it is very weakness in researching these two evidences in China.For example,species of Ainsliaea DC.are the richest in Hengduan Mountains,and adaptive radiation occurred.But there is no cytological records about them,and we know nothing that if polypoidy is involvled in the speciation occurred in the Hengduan Mountains.In this present thesis,karyology of the genus and three related genera was investigated,so was leaf epidermis.In order to obtain new evidences of taxonomy and evolution.1) 74 populations,belonging to 18 species and 1 variety of Ainsliaea,were observed and analyzed in chromosome number.The chromosome number of Ainsliaea is 2n=24 or 2n=26, diploid,no polypoid.Chromosomes of 16 species and 1 varity are reported for the first time expect A.fragrans,A.latifolia were known.They are:A.bonatii,A.latifolia var.platyphylla, A.reflexa,A.hypoleuca,A.crassifolia,A.macrocephala,A.spicata,A.yunnanensis,A.fulvipes, A.macroclinidioides,A.gracilis,A.foliosa,A.pertyoides,A.smithii,A.wuana,A.elegens,A. trinervis.a.We presented a comprehensive compare of chromosomal ploidy variation between eastern China,southern China and Hengduan Mountains,and found that polyploidy is not common in the alpine flora of the Hengduan Mountains.Diploid level of the rapid species differentiation are probably attributable to the richest habitats of Hengduan Mountains.b.The basal chromosome number of Ainsliaea DC.is 12 or 13,these two number can transfer by Robertsonian translocation.No regular occurred on horizontal and vertical distribution,Robertsonian translocation may occurred one time or many times.It is difficult to analyse karyotypes of small chromosome in Ainsliaea DC.(less than 2μm).Research the transform mechanism need in site hybridization.2) Three populations,belonging to one species and two varieties of the genus Pertya,were observed and analyzed in chromosome number.The chromosome number of Perlya is 2n=26. The basal chromosome number x=13,diploid.3) One populations,belonging to one species of Myripnois,were observed and analyzed in chromosome number.The chromosome number of Myripnois is 4x=52.The basal chromosome number x=13,tetraploid.4) Leaf epidermis of 26 species and one variety belonging to the Mutisieae from China was investigated by light microscopy.It was shown that the stomatal apparatus was mainly staurocytic and anomocytic,and presented in abaxial epiderimis of all studied species and in the adaxial epiderimis of some species.There were some differences of morphology characters between abaxial epiderimis and adaxial epiderimis,there were six types according to different numbers of subsidiary cells.The stomatal apparatus was investigated in the adaxial epiderimis in A.wuana and A.spicata for the first time.The result showed that the characters of leaf epidermis were little difference among infraspecies but can serve as a criterion for distinguishing among some species.