Growth and total-N content of Prosopis juliflora (SW) D. C. are stimulated by low NaCl levels

Abstract

In this study the early effects of salinity on growth, total N and ion accumulation and partitioning in Prosopis juliflora (common name algaroba) were studied with 30-day-old plants grown for 8 days in aerated nutrient solution (NS) free of (control) or supplied with 25, 50, 75 and 100 mmol.L-1 NaCl. Plants grown in 25 and 50 mmol.L-1 NaCl accumulated a total dry mass (DM) and shoot N content greater than the control. However, at 75 and 100 mmol.L-1 NaCl such parameters were diminished. Whole plant transpiration rates were higher with 25 and 50 mmol.L-1 NaCl and lower with 75 and 100 mmol.L-1 NaCl. Salinity did not influence shoot (80%) and root (70%) water content (WC) but reduced the K+ content of shoot while that of root was not affected. Increasing external NaCl concentrations increased K+/Na+ ratios of both plant parts. The data support the hypothesis that increase in transpiration rates and in shoot total N may account for growth stimulation of algaroba under mild salinity.