Germplasm Resource And Analysis Of Chromosomes Of Malus Sieversii

Based on the investigation of Malus sieversii(Ledeb.)Roem.germplasm resources,a wild apple species which grows in Tian mountain region in Xinj iang province,and the knowing about its growth breed characteristics,this study researches the biological characteristics of different population of Malus sieversii respectively from the perspectives of reproductive biology and cytology.The aim of this study is to provide references for scientific protection and effective utilization of this rare and endangered plant species,also provide the scientific basis on exploring the species phytogeny between M.sieversii and M.domestica.This research was carried on respectively from the following sections: 1.Investigate and record statistics about in situ protection and population regeneration.II.To explore how to promote seed germination rapidly by comparing three different methods.III.During the flowering period of M.sieversii,observe the shape and measure the length of polar and equatorial axis of the pollen;observe the germination of the pollen.IV.Collect the M.sieversii seeds of different populations including XinYuan population(XY),GongLiu population(GY),NaLa Ti population(NY)and Da XiGou population(DY);Research characteristics of chromosomes of root tip cell division and analysis karyotype;Localize rDN A by fluorescence in situ hybridization(FISH).From the research,we can conclude that: I.The germination rate was much higher with removing the seed coat,reaching to 100% after 3 days.However,the seeds treated by stratified outdoor at low temperature started to germinate after 40 days,with germination rate of 85.7%.When treated in freezer at 4?,the seeds germinated after 60 days,with germination rate of 91.3%.II.The pollen morphological shape of M.sieversii is mostly oblate or nearly circular.Germination of pollen is fairly well with the germination rate of 67% and the length of pollen tubes would reach 566.3 ?m after 4-hour incubating.III.The M.sieversii contains 34 chromosomes,indicating that this species is diploid with no polyploid produced,as well as the M.domestica;Through the karyotype analysis of the chromosomes,we can conclude that both the chromosomes of XY population and DY population has the same karyotype,with satellite,while the GY population and the King Tree with no satellite;with rDNA-FISH,it manifests that 45 S rDN A contains 3 pairs of hybridization signals with one of them is weaker than the others,and the 5S r DNA have only one pair of hybridization signals.