The Study Of Oxytropis Plant In Xinjiang, China

Xinjiang is the largest province in China, which locates eurasian continent hinterland in northwest of China, surrounding the high mountains in all directions. The latitude is 34°15′～49°10′N and longitude is 73°20′～96°25′E. The total area is about 1 657 549 km2 . The climate is extreme drought, belonging to temperate continental climate. Meanwhile photothermal resources are very rich and the vertical zone of vegetations are distributed significantly. Oxytropis plant in Xinjiang is studied on taxonomy, and on its basis species diversity, which including the characteristics of partition, vertical distribution, life-forms and the trait of species and so on is analyzed. At the end the resource is appraised and classified. The research indicates that:There are 4 subgenus and 16 sections with 97 species, 3 varieties and 6 formas in the genus of Oxytropis in Xinjiang, which account for 25% at leguminous plants of Xinjiang and 67.1% at genus of Oxytropis in China. Among them, 7 species and 1 variety are endemic in Xinjiang and 58 species only distributed in Xinjiang in China, and about 66% species belongs to the two of them. Also 1 new variety, 6 new forms and 6 new records in Xinjiang are newly added, including 5 species and 1 variety.The composition of flora was the north-temperate area, and the center of origion is central asia. So Oxytropis is the important part of plant flora at temperate alpine-cold and drought area in north hemisphere. Species are all distributed in the 11 floristic regions in Xinjiang. Junggar and Tianshan Mountains are regarded as the most abundant areas of Oxytropis in Xinjiang, especially Tianshan Mountains, the species are the richest. So we conclud that Junggar and Tianshan may be the center of modern distribution and origion differentiation areas about Oxytropis. Most species (99%) distribut in mountain areas with the altitude ranged from 1000m to 5000m , especially that in scope ranged from 1000m to 4000m, altitude ranged from 2000m to 3000m have the richest species. There are two kinds of life-forms of them, hemicryptophyto and subshurb. The former is the main kind, which account for 96% compaired with the latter(4%). But there are no annual plant and phanerophytes plant. The flora of Xinjiang are related more closer with adjacent provinces Qinghai and Tibet (the coefficient of similarity is 28.8% and 28.6%) than that of Inner Mongolica and Gansu. Compaired with Kazakhstan, they are more closer, the similarity coefficient are as high as 65.2%, while west Siberia and Kyrgzstan are less related (the similarity coefficient are 41.8% and 41.0%), the lest related places abroad are Mongolica, Tedzhikistan and Pakistan, with the similarity coefficient 29.2%, 22.8% and 11.6%.In Xinjiang many kinds of genus of Oxytropis plant have important value in grass, medical purposes and ornamental and so on, while most of them qualify the character such as enduring drought and bearing cold and resisting radiation.