Abstract: The seed bank of Kobresia humilis meadow in Qing_Zang Plateau was preliminaryly studied and the relationships among seed bank, seed rain and above_ground vegetation were compared and analysed.The results showed that there were 23 species in the seed bank in both of green up and withering stage.In species composition of the seed bank,Ranunculaceae and Leguminosae were dominant,while the percentage of Cyperaceae and Gramineae were lower. The percentage of K.humilis seeds was relatively lower with 0.97% in green up stage and 1.97% in withering stage.The species composition of the seed bank correlated with that of the seed rain(r=0.7505,P <0.01),and there were 18 common species which was 78.3% of species of the seed bank. Only 41.81% of above_ground vegetation species presented in the seed bank. The seed numbers of the dominant plant species in vegetation were smaller, with lower percentage in the seed bank. Therefore, the dominant vegetation of K. humilis et al.mainly depended on vegetative reproduction to maintain and strengthen.From vegetation to the seed bank in green up stage,the species diversity decreased by 9.94%. It implied that the seed bank was the source of vegetation regeneration,but also a mechanism of preserving species diversity of the plants.

Key words: CO₂ storage flux, effective storage flux, molar mixing ratio, air temperature, water vapor, atmospheric pressure.