摘要：Prosopis alpataco Burk. and P. argentina Phil. occupy areas with different soil characteristics within the arid zone of Argentina. Prosopis alpataco occurs in periodically flooded, clayish and saline soils, whereas P. argentina occurs in non-saline sand dunes. The capability to occupy these different habitats might be related to the presence of different adaptive features in these two species. We analyzed seedling growth of both species on clayish and sandy soils. Their emergence percentages, seedling height, biomass, and leaf area were measured in a factorial experiment (species x soils) carried out in a greenhouse. Both species showed a higher growth rate (height, biomass, leaf area and number of leaves and shoot-root ratios) in clayish soils. In sandy soils, the growth rate of P. alpataco was lower than that of P. argentina, indicating that the detrimental effects of sandy soils were greater for P. alpataco. We suggest that soil effects on growth could be due to the differences in nutrient (especially nitrogen) availability, and that P. argentina shows adaptations to sandy soils which are absent in P. alpataco. These results could explain the exclusion of P. alpataco from sandy soils but not that of P. argentina from clayish soils. Exclusion of this last species should be associated with other environmental factors like flooding or salinity, or with biological factors such as competition
