摘要
宁南干热河谷内共有种子植物８１科２７６属１１５种。当地拥有全部１５类种子植物区系地理成分，其中以热带性质的属占优势，全热带分布的类型就有８１属，比值３２．０％，当地植物区系起源古老，与外地植物区系联系广泛。宁南（金沙江）干热河谷植物区系是热带植物界在当地的残存，并逐步演化而成。
Ningnan County in sichuan Province,located at 26°50′-27°19′N,102°28′ 102°55′E,is a multinational agricultural county in the mountainous region, The dry-hot valley in Ningnanincluded that of the Heishui River which passes through the county flowing from northwest tosouthcast,and that of the Jinshajiang River which flows by way of the eastern Ningnan,withheight difference of 2 000 3000m between the ridges and valleys.The climate in the valley isappearant in the alternatioh of dry and wet seasons.The annual precipitation in 97 0mm and 91%concentrates in May and October.The mean annual temperature is 19.3.C,≥10℃ accumulatedtemperature is 6483℃ ,and the annual relative humidity is 64%.In the dry-hot valley,sepermatopytes are found about 415 species in 276 8enera and 81families. According to 8eographic distribution,the tropical and subtropical elements occupy adominant position apprently and they may be divided into 15 types. They and be integrated intothe following categories :Distribution Type Number of Genera Ratio(%)Cosmopolitan 23 Tropieal 171 67.6 Temperate76 30.0 Tethysian3 1.2Endemic 3 1.2 Total276 100.0 The origin of the flora and the vegetation of dry-hot valley in Ningnan is ancicnt. It is theareal of the tropical flora that developed in to the present state step by step.In comparison of thevalley flora in northern Yunnan and northwestern Sichuan, it can be found that they are differentin origin and succession. The vegetation found in dry-hot valley now include the primitive partand the secondary part resuted form peopole' s exploitation.
出处
《山地研究》
CSCD
1994年第1期21-26,共6页
基金
国家"七五"重大科技攻关项目
关键词
干热河谷
植物区系
分布
种子植物
Sichuan Province,Ningnan County,dry-hot valley,flora, floristic component,distribution type
