RESUMO
In semi-arid regions, is necessary to explore strategies to mitigate abiotic stresses such as water deficit and salinity. This study aimed to evaluate the stress tolerance capacity of three species subjected to different water regimes and salinity levels, based on dry matter production and water use efficiency (WUE). The species Handroanthus impetiginosus, Vachellia farnesiana, and Amburana cearensis were evaluated in combination with different water regimes (50%, 75%, and 100% of reference evapotranspiration - ET0) and salinity levels (0.18, 1.50, and 1.90 dS m-1). The results show that biomass accumulation increased at 50% and 75% ET0, while the WUE decreased at 100% ET0. The salinity level (1.90 dS m-1) caused reductions in leaf dry biomass (LDB), total dry biomass (TDB), LDB/TDB ratio, and WUE. The negative effects of high salinity on plant height were greater with the application of 75% ET0. The highest WUE was obtained at 50% ET0 for A. cearensis and H. impetiginosus, while V. farnesiana obtained the highest WUE at 75% ET0. A. cearensis exhibited the highest biomass accumulation (2.58 g) and WUE (0.21 g L-1). Overall, the species can tolerate drought and salinity conditions, being sensitive to high salinity concentrations during their initial growth.
The Caatinga is characterized by low water availability and soil salinization. Therefore, assessing the ability of native species to cope with these conditions allows for their utilization in reforestation programs in drought and salinity-exposed environments. Studies on the combined effects of these factors are scarce. The results indicated that native species show tolerance to drought and salinity conditions, albeit with some reductions in biomass production and water use efficiency at high NaCl concentrations. Among the species, A. cearensis performed the best under water and salinity stress conditions.