Morphological characteristics, biomass accumulation and gas exchange of an important species native for restoration in Semi-arid Brazilian areas affected by salt and water stress

Abstract

The Aspidosperma pyrifolium Mart. & Zucc. is one of the main species of Caatinga biome, a seasonally dry tropical forest in Brazilian Semi-arid, very prominsing for the restoration of degraded or desertified areas. The combined effects of salt and water stress on morphological dynamics, biomass accumulation and gas exchange in A. pyrifolium were investigated. The experiment was conducted in state of Pernambuco, Brazil. A completely randomised design was adopted, where the plants were submitted to four water regimes based on a percentage of the reference evapotranspiration (ET0): 25%, 50%, 75% and 100%.ET0, and four salinity levels, using NaCl: 0.2 (control), 1.8, 2.82 and 3.93 dS m−1. Biometric, biomass and gas exchange data were obtained, and water use efficiency, momentary and intrinsic water use efficiency were calculated. The water deficit affected stem diameter, and stem and root biomass. Gas exchange showed a reduction for an increase in salt and water stress. Momentary and intrinsic efficiency were maximized under a water regime of 65%.ET0 and an electrical conductivity of 1.51 dS m−1, and 67%.ET0 and 1.75 dS m−1, respectively. It is concluded that the species A. pyrifolium changes the biomass partitioning between the plant structures to compensate the salt and water stress.