Nutrição mineral de hortaliças. XXI. Efeito da omissão dos macronutrientes no crescimento e na composição química do pimentão (Capsicum annuum, L., var. Avelar)

Abstract

O presente trabalho teve como objetivos: 1 - Obter um quadro sintomatológico das carências dos macronutrientes; 2 - Estudar o efeito da omissão e presença dos macronutrientes sobre o crescimento e composição química das diversas partes da planta. Plantas de pimentão (Capsicum annuum L, var. Avelar) foram cultivadas em vasos contendo sílica e irrigadas duas vezes ao dia com solução nutritiva completa e deficiente nas macronutrientes. Surgidos os sintomas de deficiência, as plantas foram colhidas, para obtenção de seu peso seco e para serem analisados os elementos em estudo. Os autores descrevem os sintomas e apresentam dados analíticos referentes a plantas sadias e desnutridas.The present work was carried out in order to study: a) the effect of omission and presence of the macronutrients on the growth of the plants; b) deficiency symptons of the macronutrients; c) the effect of the deficiency of each macronutrient on the chemical composition of the plants. Young sweet pepper plants of variety Avelar, were grown in pots containing pure quartz. Twice a day, they were irrigated by percolation with nutrient solution. The treatments were: complete solution and deficient solutions, in which each one of the macronutrient was omitted (HOAGLAND & ARNON, 1950). When the malnutrition symptons appeared, the plants were harvested and divided into: roots, inferior and superior stalks, inferior and superior leaves, new and old fruits. The dry matter was analysed chemically. Conclusions: 1) symptons of malnutrition are observed for N, P, K, Ca, Mg and S; 2) the symptons of deficiencies of K and Mg appear on the new leaves; 3) this variety is resistent to blossom-androt; 4) plants grown in N and Ca deficient solutions, show the largest reduction in development, compared to growth of normal plants; 5) the height of the plants is not affected by the omission of sulphur; 6) there's no reduction of the number of leaves on plants deficient in Mg; 7) the nutrient content expressed in porcentages in the ripened leaves of plants cultivated under normal nutrition conditions and under deficient conditions, expressed in Confidence Interval at 5% level, are: