Abstract:The plant growth,tissues biomass and biomass allocation of two dominant species (Glycyrrhiza uralensis and Cynanchum komarovii) were observed under different grazing intensities in desert steppe.The results showed that:(1)The plant height and ground diameter of G.uralensis,and plant height of C.komarovii were decreased after an initial increase with increasing of grazing intensities,with the highest values under light grazing,and there were significantly decreased under heavy grazing.(2)Stem biomass,leaf biomass and total biomass of G.uralensis and C.komarovii were significantly affected by grazing,and decreased after an initial increase with increasing of grazing intensities.The root biomass of G.uralensis and C.komarovii showed different trends under different grazing intensities.(3)The biomass allocation patterns of G.uralensis and C.komarovii were roots>leaves>stems.With increasing of grazing intensities,the root biomass ratio of G.uralensis decreased after an initial increase,but stem biomass ratio tended to decreased and leaf biomass ratio tended to increased;while the root biomass ratio of C.komarovii increased after an initial decrease,contrary to stem biomass ratio and leaf biomass ratio.It suggests that differences in morphological plasticity and biomass allocation patterns of these two species indicated that they had different ecological strategies to grazing.