喀喇昆仑山-昆仑山地区植物区系组成和分布规律的研究

FLORISTIC COMPOSITION AND DISTRIBUTION IN THE KARAKORUMKUNLUN MOUNTAINS

喀喇昆仑山－昆仑山地区植物区系组成比较贫乏，在东经９０°以西仅有高等植物约８２７种，分属于６０个科２７２属。其中，蕨类植物仅３科３属５种，禾本科植物最多，有１３６种。菊科、豆科、十字花科、莎草科和藜科分别排列在第二至第六位，均含５０种以上。区系地理成分组成以中亚的为主，青藏高原成分居第二位。但是，不同的地段存在着明显的差异，在昆仑山主脊南侧高原和中昆仑库木库勒山间盆地青藏高原成分占有的比例高于中亚成分。随着海拔的升高，区系地理成分的组成也发生了有规律的变化，中亚成分占有的比例下降，适应高寒气候的青藏高原成分占有的比例急剧升高，在海拔４２５０ｍ左右两者占有的比例相等，在海拔５０００ｍ以上青藏高原成分显著超过中亚成分。对该地区８个地段的植物区系相似性分析显示，昆仑山主脊南北两翼植物区系的差异远大于东西方向的差异。植物区系地理成分的组成与海拔高度的关系以及植物区系的地理分异规律说明，昆仑山脉作为中亚植物亚区与青藏高原植物亚区之间的分界是符合客观实际的。

The area of the KarakorumKunlun Mountains is not so rich in flora.827 species,subspecies and varieties of higher plants were recorded in the area of ca.400,000km2.Those plants belong to 272 genera of 60 families.Among them there are only 5 fern species of 3 genera of 3 families and 14 gymnosperms of 3 genera of 3 families.There are 136 grass species (Gramineae).The families each of which have more than 50 species observed there were Compositae,Leguminosae,Cruciferae,Cyperaceae and Chenopodiaceae. Of the taxa in the area,44.5% belongs to the Central Asian geographic elements and 21.7% to Qingzang Plateau elements in terms of genera. But the Qingzang Plateau elements dominated in the sections of the Kumkol Basin of the Middle Kunlun(see Fig.1 Ⅰ5),the southern flank of east part of the West Kunlun(Ⅱ2) and the southern flank of the Middle Kunlun(Ⅱ3).The higher the altitude of the belts is,the greater the proportion of Qingzang Plateau geographic elements is .The proportion of Centra Asian elements decreases while the proportion of the Qingzang Plateau elements increases as the altitude raises.These two elements are similar in proportion at ca.4250 m above sea level.The floristic differentiation between the southern and the northern flanks of the Kunlun is much more apparent than that between the West and Middle Kunlun.The results of this study show that the demarcation line between the Central Asian subregion and the Qingzang Plateau subregion runs along the KarakorumKunlun Mountains.