中文摘要：

通过对青藏高原中部兹格塘错流域12个样品的花粉资料进行分析，结果显示，花粉组合特征能够很好地反映流域植被的总体特征。研究区花粉组合主要以草本植物花粉为主，其中莎草科花粉含量占绝对优势，平均为58．1％，其次为禾本科花粉，平均为14．7％，还有少量的菊科、蒿属、蔷薇科、藜科、石竹科和毛莨科等植物花粉。同时，笔者利用禾本科＋蒿属与莎草科含量[（G＋A）／Cy]比值作为区分青藏高原中部兹格塘错流域高寒草原区与草甸区不同植被类型的依据，并认为其比值大于0．1为高寒草原区，反之为高寒草甸区。该研究为青藏高原中部及其官地区利用花粉萤建古植被提供了萤要的参考依据。

英文摘要：

A total of 12 surface soil pollen samples taken from the Zigetang Co area, central Tibetan plateau have been analyzed. The results show that the pollen assemblages of surface soil samples generally reflect the modern vegetation. The pollen flora is mainly composed of herb pollen, which dominated by Cyperaceae （58. 1%） and Gramineae （14. 7%）, with a very low content of other pollen such as Compositae, Artemisia, Rosaceae, Chenopodiaceae, Caryophyllaceae and Ranunculaceae. The ratio of （Gramineae＋ Arternisia）/Cyperaceae [（G＋A）/Cy-] proposed here by the authors is useful to sig- nificantly identify the vegetation condition between Alpine steppe and Alpine meadow. The result shows that the mod- ern vegetation has higher ratio （〉0.1） of Alpine steppe and the lower ratio （〉0.1） of Alpine meadow. This study provides theoretical bases for quantitative reconstructions of palaeoclimate and palaeovegetation conditions based on fossil pollen spectra from lake sediments in the central Tibetan plateau and the surrounding areas.