Crescimento de mudas de pupunheira (Bactris gasipaes H.B.K.) em função de relações do K com o Ca e com o Na, em solução nutritiva

Abstract

The experiment was carried out in nutrient solution, under greenhouse conditions at the Soil Science Department - Lavras Federal University, Minas Gerais state, Brazil, to evaluate the effect of different relationships of potassium with calcium and with sodium, upon growth of peach palm (Bactris gasipaes H.B.K.) seedlings. The experimental design was in randomized blocks, with nine treatments and four replications. The treatments consisted of the foolowing K/Ca relationships: 0.0/3.0; 1.0/2.5; 2.0/2.0; 3.0/1.5; 4.0/1.0; 5.0/0.5; and 6.0/0.0 mmol L-1 and two additional treatments with variation in the concentration of sodium constituting the K/Na relationships of: 2.0/0.0 and 1.0/2.0. In this last one part of the potassium was substituted by sodium. The experimental units were constituted by one vase containing one plant. Height, perimeter at the stem level, leaf area and dry matter of leaves, stipes and roots were evaluated. The K/Ca relationships of 2.0/2.0 and 3.0/1.5, were the ones that provided larger medium values for leaf area and dry matter of parts of the plant, and this last one, favored more the growth of the plants. In the treatments without sodium or with the increase concentration of sodium all variables evaluated were negatively affected. Symptoms of deficiency of potassium in the leaves, followed by drastic reduction in growth appeared in the plants submitted to relationships where it was absent or with 1 mmol L-1.