Study On Plant Diversity In Gansu Yanchiwan National Nature Reserve

Plant diversity is an important part of biological diversity. On the basis of theinvestigation of Gansu Yanchiwan National Nature Reserves, in combination withinformation collection, and reading, identification and arrangement of specimens, the thesiselaborated on the composition of Spermatophytes flora, vegetation type, and plant diversity.The results were showed as follows:There are417species,181genera and45families in Gansu Yanchiwan National NatureReserves, which contain109endemic species of China and Pomatosace、Metaeritrichium、Przewalskia、 Xanthopappus, total of4endemic genera of China, and Gymnocarposprzewalskii is the only one into the first grade of protected of plants. There have154speciesof drug plants,139species of halophytic plants,131species of forage plant resources, and54species of C4plant in the reserve. The reserve has Compositae、Poaceae、Leguminosae、Ranunculaceae、Chenopodiaceae Brassicaceae、Cyperaceae、Rosaceae、Gentianaceae totalof9dominant families and Nitrariaceae、Ephedraceae、Tamaricaceae、Zygophyllaceae、Gentianaceae、Chenopodiaceae、Ranunculaceae、Elaeagnaceae total of8typical families.The reserve is a distribution center of Nitraria in China.23species of Angiospermae werereported as new records in geographical distribution in the territory of Gansu Province fromthe Gansu Yanchiwan National Nature Reserve. They were Allium schrenkii Regel,Callianthemum pimpinelloides (D.Don)J.D.Hooker&Thomson, Ranunculus dongrergensisHandel-Mazzetti, Ranunculus dongrergensis var. altifidus W. T. Wang, Ranunculus similisHemsle, Ranunculus involucratus Maximowicz var. minor L. Liou, Ranunculus banguoensisL. Liou, Ranunculus natans C. A. Meyer, Ranunculus pectinatilobus W. T. Wang,Ranunculus yechengensis W. T. Wang, Thlaspi cartilagineum J. Mayer, Astragalus heydeiBaker, Astragalus datunensis Y.C.Ho, Astragalus arnoldii Hemsley&H.Pearson, Astragalusmattam H.T.Tsai&T.T.Yu, Potentilla pamiroalaica Juzepczuk, Pleurospermum hookeri C. B.Clarke var. haidongense J.T.Pan, Gentiana crenulatotruncata (C.Marquand) T.N.Ho,Gentianella turkestanorum(Gand.)Holub, Gentianella pygmaea (Regel&Schmalhausen)Harry Smith, Metaeritrichium microuloides W. T. Wang, Saussurea wellbyi Hemsley,Saussurea thomsonii C.B.Clarke.The results of characteristics of flora show:1. Cosmopolitan of families, which contain 88%of total species, take up62.2%of total families.2. The statistics of flora of genera showthat the temperate, which principal part is north temperate, is the dominant areal-type. Tethysareal-type takes important position, which indicate the reserve’s climate is dry and the florais ancient. Few ones with the temperate Eastern Asian flora have been found. The affect oftropical is weak.3. The statistics of flora of no-endemic of China show that C.Asia is thedominant areal-type. The temperate is the important part of the areal-type.4. The statistics offlora of endemic of China show that Tangut&Hengduan mountain region is the origin of theflora. The increase of species richness is mainly from the arid northwest region. From theresult of statistics of flora of genera and species, The Tethys’s retreated and theQinghai-Tibet Plateau’s uplift of the formation has deep influence of the flora. Thecommunication between the flora and Sino-Japan flora was enhanced by Qilian mountain.The results of plant traits show:1.The types of life form are rich. Perennial herb, whichhas278species, take up66.9%, is the main body of the plant traits. Annual herb has47species take up11.3%. Shrub has34species, take up8.2%. Subshrub has28species, take up28%.2. Hemicryptophytes has220species, take up52.9%, is the main body of the growthform. Phanerophytes has39species take up9.4%. Chamaephytes has21species, take up5%.Cryptophytes has89species, take up21.4%. Therophytes has47species,11.3%.3. Thegeneral trait of leaves are the small leaf type, thick leaf texture, many have coat, with themore basal leaves, many have leaf sheath.4. The types of inflorescence are rich. There are89species solitary. The indeterminate inflorescence has294species, take up88.3%. Itcontains83species raceme,49species panicle,56species spike,9species corymb,17species umbel,6species ament,74species capitulum. The determinate inflorescence has39species. Flower and fruit period are focus on6-9month.5. The types of fruit are rich. Theficshy fruit contains two types, berry has8species, drupe has8species. The dry fruit marksoff dehiscent fruit and achenocarp. Dehiscent fruit contains91species capsule,9speciessilique,16species silicle,7species follicle,35species legume. Achenocarp contains122species achene,26species utricle,4species samara,29species nut,6species schizocarp,55species caryopsis.