Crescimento e nutrição mineral de mudas de umbuzeiro (Spondias tuberosa Arr. Cam.) submetidas a níveis de salinidade em solução nutritiva

Abstract

To evaluate the growth and the mineral nutrition of umbuzeiro seedlings, under salt stress, an experiment in nutrient solution was conducted, under greenhouse conditions in the Soil Science Department of the Federal University of Lavras, Brazil. The experimental design was randomized blocs, with four replications and six doses of NaCl (0, 20, 40, 60, 80, and 100 mmol L-1). The seedlings were adapted in the Hoagland solution to 25, 33 and 50% of ionic forces, staying for fifteen days in each concentration. After this period the seedlings were conduced for 60 days in nutrient solution with 100% of the ionic force and the treatments with NaCl. The change of the solutions was made biweekly. The NaCl in the nutrient solution affected negatively the growth of the umbuzeiro seedlings. The umbuzeiro was classified as moderately tolerant to salinity when cultivated below 31 mmol L-1 of NaCl. The roots compartmentalization is the possible mechanism of tolerance to salt in umbuzeiro seedlings. The order of macronutrient accumulation was: N > K > Ca > P > S > Mg and N > Ca > K > P > S > Mg, in the absence and with 100 mmol L-1, respectively and the micronutrient accumulation, except Cl, was: Fe > B > Mn > Zn > Cu, independent of the concentration of NaCl in the solution.