关键词: 黄土高原, 草原植被, 植物区系, 地理成分, 植物地理学

Abstract:

Grassland is one of the most important vegetation types on the Loess Plateau.Howeever the relationship between the Loess Platean and the Eurasion steppe has not yet been elucidted. In this study, the seed plant flora of the Loess Plateau was used as a single research object for the first time. On the basis of the field vegetation survey and a large number of references, a seed plant flora list of grassland plants in the Loess Plateau was established. Based on the theories and methods of geobotany, study of plant flora composition, life type, water ecotype, floristic character, endemic phenomenon, geographical composition and geographical relations are carried out. The seed plant flora of grassland in the Loess Plateau and Inner Mongolia plateau is compared and analyzed. The main results are as follows:The basic characteristics of the grassland flora in the Loess Plateau are clarified; the species similarity of the seed plant flora on the Loess Plateau and the Inner Mongolia plateau grassland is relatively high on family and genus level, not on species level. There are significantly differences in the geographical compositions between Loess Plateau steppe and Inner Mongolia plateau steppe; the most important difference is that the seed plant flora of the Loess Plateau steppe is closely related with that of the Northeast China. East Asian components occupy a more important position in the seed plant flora of the Loess Plateau steppe; the vertical zonal geography play an important role in the formation of the loess plateau steppe.

Key words: Loess Plateau, Grassland vegetation, Seed plant flora, Geographical elements, Geobotany