Régimen hídrico e intercambio de gases de Prosopis laevigata (Humb. &Bonpl. ex Willd.) M. C. Johnst. en dos ecosistemas semiáridos del sur de Sonora

Abstract

Introduction: Among the adverse conditions of forest ecosystems, salinity anddrought are the abiotic factors that largely modify the genetic and productiveexpression of species. Objective: To evaluate the effect of salinity and drought on the water regime and gasexchange of mesquite (Prosopis laevigata [Humb. & Bonpl. ex Willd.] M. C. Johnst.)in two semi-arid sites, Eco Camping and Bahia de Lobos, in southern Sonora,Mexico. Materials and methods: The water and osmotic potentials were determined in theroot, stem and leaves of plants taken at random with similar morphological traits(height of 1.5 m and stem diameter of 0.15 m measured at 1.3 m). In addition,photosynthesis, transpiration and water-use efficiency were evaluated. Results and discussion: Water and osmotic potentials decreased significantly (P =0.0043); the osmotic potential was the lowest in the three organs measured, forminga potential gradient, an aspect that explains the maintenance of transpiration in bothconditions (salinity and drought). Photosynthesis did not vary significantly, buttranspiration did. In both sites, water-use efficiency exceeded 6 μmol CO2/H2O;however, there was greater efficiency in the saline ecosystem due to the transpirationdecrease. Conclusion: Mesquite has the ability to tolerate the stressful conditions of salinityand drought in southern Sonora, showing less impact in water relations and gasexchange in the salinity condition.