The Embryology Of Stixis

In recent years,the study of plant molecular systematics has made rapid progress,and the life tree of the order of the angiosperm and the hierarchy has been established.However,in the phylogenetic analyses of a wide range of taxa,sampling is often relatively sparse,molecular systematics of sampling to some relatively narrow distribution area is,in some eyes,a category of unresolved substantive.In the GRFT branch,spot fruit cane(Stixis)as the core of cruciferous members,in the traditional sense is placed in the Capparidaceae(Capparaceae),its systematic position and its taxonomic position has been controversial.In recent years,through the analysis of the molecular sequence data of the fruit of the vine and the morphological analysis,it is suggested that a new branch of the family should be established.The classification characteristics of embryology are relatively stable,which can be used to supplement the molecular phylogeny and the special characteristics at the genus level.However,the embryological characteristics of the genus.So,here,we mainly use the method of paraffin section and semi thin sections,at the micro level,the system of Yunnan province is located in the China spot fruit cane embryonic development process and describes the spot fruit of cane Microsporogenesis and Megasporogenesis,the spot fruit cane of female and male gametophyte,provide the characteristics of embryology for its.The results show that:1.The embryological features of Stixis.The Stixis of anther four chamber,the anther has 4 layers,including epidermis,fiber layer,middle layer and tapetum.In microspore mother cells during meiosis,cytokinesis type at the same time,the tetrad stage of microspore is the tetrahedron.Ovule thick nucellus,is double bead,bead hole for linear.Spore original cell is divided into some produce wall cells and a cells grew into megaspore mother cell,megaspore tetrad is T.With seven cells mature embryo sac is smartweed model,eight nuclear: have a eggs and two nuclear central cells,help cells have two,three antipodal cells.Stixis mature pollen grains of two cell type,three hole groove.2.Stixis should be removed from Capparaceae.Our results also show that Stixis is a member of Capparaceae.The genera,together with Forchhammeria,Gyrostemonaceae,Resedaceae,and Tirania,form a clade with strong support.Stixis is closely related to Tirania,a relationship that is also supported by morphological characters,such as six sepals and three-or four-locular ovaries.3.The Stixis belong to should be embedded in the core Brassicales GRFT branch.Through the spot fruit cane and Brassicales embryological features of the other members of the comparison,found many similar characteristics,glandular tapetum,mature pollen is 2-cell type,female gametophyte development type is smartweed model,pollen three hole groove.So,our findings support spot fruit cane as a member of the GRFT branch.4.The current study provides new evidence,the Stixis should be as an independent family.Section compared to the wood belongs to and mignonette of embryology characteristics show that the spot fruit cane of anther wall belongs to basic development type,ovule raw,nucellus is always a single spore cells,inner integument is two layers,there are many thick bead be.Features different from mignonette and ring core sister groups.In the APG,IV stixis is placed in the ring core,the results do not agree with this opinion,but support Stixis as an independent family.To sum up,the present study do not only investigated the first comprehensive embryological features of Stixis,but also provide new evidence for Stixis should be treated as a separate family.