The replacement of potassium (K) for sodium (Na) is recognized in the literature to increase some plants productivity, but little is known about the behavior in forest tree species. Therefore, the objective of this study was to evaluate the initial growth of Enterolobium contortisiliquum and Sesbania virgata in replacement of K by Na in Hoagland and Arnon nutrient solution. The factorial design was 2x5, consisting of two species and five substitution levels of K for Na (0; 33.3; 50, 66.6 and 100%), with four replications. The experiment was conducted in Leonard pots with 1L capacity, with periodic exchange of nutrient solution. The plants were harvested 50 days after the start of the study, when we evaluated the morphometric characteristics. The material was washed, dried and determined dry matter of roots, leaves and stem. Root and shoot materials were ground and analyzed for K and Na content. The shoot dry matter (stem + leaves), the ratio of root / shoot and build up of K and Na in roots and shoot were obtained by calculating. The replacement of K by Na promoted significant differences in plant development, content and build up of K and Na. The species Sesbania virgata showed the best initial growth and accumulated higher amount of K and Na in the shoots.
Initial growth; Legumes forest tree species; Salt stress
