Characterization of the effects of macronutrient deficiencies in mangabeira seedlings/Caracterizacao dos efeitos de deficiencias de macronutrientes em mudas de mangabeira

Knowledge of the mineral nutrition requirements of mangabeira (Hancornia speciosa Gomes) is relatively scarce and rudimentary because there is a lack of consistent data concerning its nutritional demands at different developmental stages. The aim of this research was to characterize the visual symptoms of macronutrient deficiencies and to evaluate the effects of these deficiencies on the growth, the production of dry matter, and the leaf content of mangabeira. To achieve this goal, a greenhouse experiment was conducted at the Goiano Federal Institute (Instituto Federal Goiano) in Rio Verde--GO, from January to June 2011 in which mangabeira plants were arranged in a random block design and grown in nutrient solutions. This experiment was replicated four times. The plants were treated with either a complete nutrient solution or a nutrient solution from which the individual macronutrient of interest (nitrogen (N), phosphorous (P), potassium (K), magnesium (Mg), calcium (Ca), or sulfur (S) had been omitted. The omission of a macronutrient from the nutrient solution resulted in morphological alterations that were characteristic symptoms of the particular nutritional deficiency and caused decreases in growth and dry matter mass production. The accumulation of macronutrients displayed the following order in mangabeira leaves: N>K>Ca>P>S>Mg. Index terms: Hancornia speciosa Gomes, mineral nutrition, hydroponics. Os conhecimentos de nutricao mineral da mangabeira (Hancornia speciosa Gomes) sao relativamente escassos e incipientes, faltando dados consistentes sobre sua demanda nutricional desde a fase de viveiro ate a fase de producao. Com o objetivo de caracterizar os sintomas visuais de carencias de macronutrientes, avaliar os efeitos da deficiencia no crescimento, producao de massa da materia seca e conteudo foliar de mangabeira, foi conduzido um experimento em casa de vegetacao no IF Goiano em Rio Verde--GO, nos periodos de janeiro a junho de 2011, onde plantas de mangaba foram cultivadas em solucao nutritiva, no delineamento de blocos casualizados, com quatro repeticoes. Os tratamentos foram constituidos de solucao nutritiva completa e omissao individual de nitrogenio (N), fosforo (P), potassio (K), magnesio (Mg), calcio (Ca) e enxofre (S). A omissao dos nutrientes na solucao nutritiva resultou em alteracoes morfologicas, traduzidas como sintomas caracteristicos de deficiencia nutricional, diminuicao no crescimento e producao de massa da materia seca, e o acumul