The Study On Geographical Variation And Genetic Diversity Of Magnolia Sprengeri. Pamp.

Magnolia sprengeri Pamp., deciduous, belongs to Magnoliaceae Jussieu, was distributedin temperate and north mid-subtropics mountain area about800-1200m altitude in China. Onthe one hand, because of the beautiful flower and abundant morphologic variation, M.sprengeri Pamp. has great gardening potential value. On the other hand, M. sprengeri hasbeen severely affected by the rapid population increasing, environmental degradation andoverexploitation. Because of the severely habitat destruction, M. sprengeri has been listed as‘‘Vulnerable’’(VU) in the Red List of Environmental Agency.In this thesis, geographical distribution and genetic diversity of M. sprengeri werestudied for better protection and utilization.The main conclusions were drawn as following:M. sprengeri was mainly distributed in mountain at altitude of800m-2100mmiddle-lower Yangtze area, acrossing the north subtropical humid region, humid subtropicalzone, most parts of the south temperate zone, eastern area of central subtropical andsubtropical humid region. Due to the influence of the qinling and bashan lateral mountains,wushan, xuefeng and taihang vertical mountains and the Yangtze river——the China’s largestrivers, flowering phenology of M. sprengeri showed the tendency of moving forward fromsouth to north, and the flowering time of M. sprengeri in Hunan, Hubei and Henan wereearlier than vicinity on the same latitude.Different degree of variation was observed on morphological characters. Generallyspeaking, the morphological characters variation of M. sprengeri in south of Yangtze Riverwere more abundant than M. sprengeri in north of Yangtze River. It could be divided into twogroups by the Yangtze River as a natural reproductive isolation boundary, namely the Redgroup in south of Yangtze River and White group in north of Yangtze River. Themorphological variation of M. sprengeri showed like this:Tepal numbers: M. sprengeri distributed in north of the Yangtze River region was more stable than south of the Yangtze River region as12(11-13), except Pop6(8-13). Thesignificant variation were observed between individual plants in south Yangtze River region,All tepal variation types was observed in Pop9, the main variety was showed as12-15;Pop7was observed as11-16, but Pop8was only observed as11-12. Tepal arranged oncolumnpillar normally in whorls: when tepal under12, tepal arranged as4per whorl, notmatter8tepals or12tepals; when tepal greater than12, tepals arranged as3whorls,increasing tepals added to each whorl from adaxial side to abaxial side. Until cannot be placed,the tepal arrangement showed as spiraling alignment.The tepal color of M. sprengeri in investigation area performed more and more pinkfrom north to south, i.e., the type4(abaxial colour and adaxial colour are presented in pink)all distributed in south of Yangtze River region; Type3(abaxial colour is presented in paleand adaxial colour is presented in pink) mostly distributed in south of Yangtze River regionand scattered in north of Yangtze River region; All white type1(abaxial colour and adaxialcolour are presented in pale) mostly distributed in north of Yangtze River region and a fewindividuals scattered near the Yangtze river in south of Yangtze River region; Type2(abaxialcolour is presented in pale and adaxial colour is presented in half pink) only have scattered innorth slope of Qinling mountains in north of Yangtze River region.The tepal texture of M. sprengeri in south of Yangtze River region performed more thinand more wrinkles, the tepal texture of M. sprengeri in north of Yangtze River regionperformed more thick texture and less wrinkles. The flower shape of M. sprengeri in north ofYangtze River region was major with cup shape and bowl shape, in south of the Yangtze Riverregion was peony shape, chrysanthemum, etc.The mostly CV value and R value of M. sprengeri in south of the Yangtze River regionwere greater than the M. sprengeri in north of Yangtze River region, the genetic variation ofreproductive organ (flower organ) was greater than vegetative organ (leave organ). It wasobserved by morphology and molecular method that the genetic diversity of M. sprengeri insouth region was more abundant than M. sprengeri in north region, and the individual geneticvariation contribution of M. sprengeri was greater than the contribution among population oramong investigation regions.M. sprengeri showed abundant morphological variation. For example, the variation range of tepal color and tepal number was relatively wider than many other characteristics, thissituation was also observed in other species of Magnolia normally. Hence, it was questionableto division specieses or varieties using one or two characteristics like tepal color or tepalnumber this kind of characteristics as important standard. Multi-morphological characters orcomprehensive characters should be used for building a new species or variety asociation withpalynological and molecular biological methodology.Intraspecific variation of M. sprengeri was richness; the variation in most characters wasmuch wider than heretofore recognized. For example, the variation of tepal color and tepalnumber showed almost continuous changing. Therefore, M. sprengeri should be treated as acomplex species, the “white type” M. sprengeri (M. sprengeri var. elongata) was replaced byM. sprengeri var. sprengeri. M. multiflora, which was divided from M. sprengeri as themultiple flower buds placed on the branch tip, M. wufengensis and M. wufengensis var.multitepala which were divided from M. sprengeri as the tepal color and tepal number, shouldbe treated as the morphological variation type of M. sprengeri.