新疆十字花科区系地理成分分析

新疆地处欧亚大陆腹地，十字花科植物有76属，180余种，从垂直分布的情况来看，主要分布于阿尔泰山和天山的亚高山草甸和森林草甸带、昆仑山的高寒荒漠和荒漠草原及帕米尔高原的高山草甸带。从水平分布来看，有5个分布较集中的区域：阿尔泰山地、准噶尔西部山地、天山中西部山地、天山东部山地、昆仑山和帕米尔高原，其它地区零散分布。其区系地理组成分中76个属归入7个分布区类型和9个变型。其中以地中海区、西亚至中亚分布型、北温带和中亚分布型为主，单种属、寡种属比例偏高，其种类又以新疆北疆偏多。可认定该区是十字花科的分布中心。与邻区的比较发现，新疆与周边植物区系关系密切，物种交流的机会较多，尤其是东西方向是植物区系交流的重要通道。新疆十字花科分布规律在一定程度上反映了新疆植物区系的特点。

Analysis on Geographical Elements of Brassicaceae Area of Xinjiang

Xinjiang is situated between Europe and Asia.There are about 76 genera with 180 spcies of Brassicaceae in this area.On vertical distribution,plant of Brassicaceae mainly is distributed in subapine meadow and conislvae in Tianshan mountain and in Pamir Plateau.On level distrbution,there are five regions of more species distribution:Altay Mountain Region,West Mountain Region of Junggar,Centre West Tianshan Mountain Region,East Tianshan Mountains Regin,Kunlun Mountains Regin and Pamir plateau,and rare distribution in other regions.These elements of 76 genera were divided into 7 distribution types and 9 subtypes.The dominating distribution typies are Mediterranean,W.Asia to C.Asia,North Temperate and C.Asia;the species are mostly of North-Xinjiang;and the proportion of autogenus,widowedgenus is high,which made it clear that this region is the distribution center of Brassicaceae.Comparative research with neighborhood regions indicates that Xinjiang flora is allied with them,and the opportunity for species exchange is abundant.It showed that the east-west direction is important for flora exchange.The distributing regulation of Xinjiang Brassicaceae reflected the characteristics of Xinjiang flora to some extent.