Abstract: In order to evaluate differences in phosphorus (P) absorption capacity and acid phosphatase activity,two genotypes of wild barley (Hordeum brevisublatum) with high P efficiency (IS-22-30, IS-22-25) and one genotype with low P efficiency (IS-07-07) were grown in pots treated with four different P application rates (0, 30, 60, and 90 mg/kg soil). With increasing P concentrations, the biomass and P accumulations of all tested genotypes increased, however the root/shoot ratios decreased. For all P treatments, both the biomass and P accumulation of high efficiency genotypes were significantly higher than that of the low efficiency genotype. For all tested genotypes,the concentrations of available P and water soluble P in rhizosphere soils were significantly lower than in non-rhizosphere soils. For lower application rates (0, 30, 60 mg/kg soil) in rhizosphere soils, the concentrations of available P and water soluble P were lower in the high efficiency genotypes than in the low efficiency genotype. In rhizosphere soils with application rates of 0 and 30 mg/kg soil, the acid phosphatase activity of the high efficiency genotypes was significantly higher than that of the low efficiency genotype. These results suggest that wild barleys with high P efficiency have the activation capability to adapt to low P soils. With increased levels of P application, acid phosphatase activities in the leaves and roots of all tested genotypes significantly decreased. Furthermore, acid phosphatase activities in the more efficient genotypes were significantly higher than in the low efficiency genotype, indicating that the P recycling capacity of the more efficient plants is higher and that their increased acid phosphatase activities promote absorption in conditions of low P stress.