秦岭豆科植物区系特征和生物多样性

AN ANALYSIS OF LEGUME FLORISTICS AND BIODIVERSITY OF QINLING MOUNTAIN

豆科是组成秦岭植物区系的四大科之一．计约５１属１７５种，不仅含有大量的草本植物，亦有发育丰富的灌木以及乔木和藤本植物．其中有中国特有种７８种，秦岭特有种２５种，这些豆科植物具备了豆科不同发育阶段、演化级别的类群，汇聚了温带热带多种地理成分。从种类组成和属的分布类型来看，秦岭豆科植物区系以温带成分占主导地位，与秦岭种子植物区系的温带性质的结论一致．山羊豆族ＴｒｉｂｅＧａｌｅｇｅａｅ及其近缘类群处于豆科系统演化中的高级阶段，在秦岭豆科植物中占相当比重，说明物种分化是十分活跃的。秦岭植物区系在中国植物区系中极显著的过渡性以豆科为典型例子集中表现在两个方面：（１）在秦岭区域内，南坡、北坡、西端、东端分别聚集了各种地理成分，（２）作为中国西南一东北植物区系中物种扩散迁移的通道．以属的相似性为基础，比较了秦岭与神农架、喜马拉雅山、贺兰山、长白山的区系，表明秦岭是我国地理分布格局中一个最重要的结点。

Qinling Mountain is the natural geographic dividing line between the south andnorth China. Leguminosae is one of four largest families in this region. The discussionsof the paper have four aspects: 1. There are 13 areal-types of genera (Wu, 1979) in theregion. The North Temperate type which including 6 genera and 37 species,has the richest species. 2. With respect to the phylogeny chart of legumes (Polhill, 1981 ), the groupslocated in the major evolutionary path not only have primitive but also advanced. 3. Themost striking floristic transition in China is presented in the region. The tropic and subtropic elements distribute to the southern slope. Many Central Asia elements distributethe northern slope. The Qinghai-Xizang Plateau elements are radiated to the westernQinling Mountain. The region is a corridor of the Northeast-Southwest China elements.4. The relationships among Qinling Mountain,Shennongjia,Himalaya, Helan Mountainand Changbai Mountain are indicated by a MST diagram based on the genera similarity.Qinling Mountain is an important node.