RESUMO A determinação do acúmulo de nutrientes durante o ciclo vegetativo é essencial para estabelecer o manejo nutricional. Objetivou-se avaliar o acúmulo de matéria seca e a exigência nutricional, estabelecendo as curvas de absorção, a época ideal de manejo e a ordem de extração dos elementos. O experimento foi conduzido em casa de vegetação com delineamento experimental inteiramente casualizado com oito períodos de coleta aos 10, 20, 30, 40, 50, 60, 70 e 80 dias após a emergência (DAE), com quatro repetições. Em cada período, ocorreu uma coleta de forma destrutiva, para determinar a matéria seca e, assim, estimar o conteúdo de macro e micronutrientes. Foram ajustados, quando significativos, modelos não lineares para explicar o acúmulo de matéria seca e absorção de nutrientes. A equação sigmoidal foi o modelo que melhor representou a curva de crescimento das plantas de feijão-de-metro com acúmulo máximo de biomassa aos 80 DAE de 177,5 g planta- ¹. A fase de maior exigência nutricional da cultura é no período de 20 a 45 DAE (início das fases de florescimento e frutificação), onde deve ser realizado o manejo nutricional. A ordem decrescente da extração total de macronutrientes pela planta no final do ciclo foi de K>Ca=N>S=P>Mg com respectivos valores de 2.668,3 mg planta-¹, 2.331,1 mg planta-¹, 2.279,2 mg planta-¹, 507,5 mg planta-¹, 496,3 mg planta-¹ e 213,2 mg planta-¹, e de micronutrientes Fe>B>Mn>Zn>Cu, com 10.933,1 µg planta-¹, 6.310,8 µg planta-¹, 4.746,8 µg planta-¹, 2.854,1 µg planta-¹ e 717,1 µg planta-¹, respectivamente.

ABSTRACT Knowing about the nutrient uptake during plant cycle is essential for nutrient management decisions. We evaluated dry matter accumulation and nutrient demand, and it to determine the uptake curves, the ideal phase for management, and element extraction order for yard long beans. The experiment was carried out in a greenhouse. The experimental design was completely randomized, with eight collection periods, at 10, 20, 30, 40, 50, 60, 70 and 80 days after emergence (DAE), and four replicates. For each period, destructive sampling was performed and the sample’s dry matter content was determined, so that it could be used to estimate macro- and micronutrient contents. When significant, nonlinear models were adjusted to explain dry matter accumulation and nutrient uptake. The sigmoidal equation was the model which best depicted the growth curve for yard long bean, which reached a maximum biomass accumulation of 177.5 g plant-¹ at 80 DAE. The crop's most demanding phase in terms of nutritional requirements is from 20 to 45 DAE, which is the ideal phase for nutrient management. The element extraction order at the end of the plant's cycle was K>Ca=N>S=P>Mg (macronutrients) with values of 2,668.3 mg plant-¹, 2,331.1 mg plant-¹, 2,279.2 mg plant-¹, 507.5 mg plant-¹, 496.3 mg plant-¹ and 213.2 mg plant-¹, and Fe>B>Zn>Mn>Cu (micronutrients), with 10,933.1 µg plant-¹, 6,310.8 µg plant-¹, 4,746.8 µg plant-¹, 2,854.1 µg plant-¹ and 717.1 µg plant-¹, respectively.

In the present study, a quassinoid, neosergeolide, isolated from the roots and stems of Picrolemma sprucei (Simaroubaceae), the indole alkaloids ellipticine and aspidocarpine, isolated from the bark of Aspidosperma vargasii and A. desmanthum (Apocynaceae), respectively, and 4-nerolidylcatechol, isolated from the roots of Pothomorphe peltata (Piperaceae), all presented significant in vitro inhibition (more active than quinine and chloroquine) of the multi-drug resistant K1 strain of Plasmodium falciparum. Neosergeolide presented activity in the nanomolar range. This is the first report on the antimalarial activity of these known, natural compounds. This is also the first report on the isolation of aspidocarpine from A. desmanthum. These compounds are good candidates for pre-clinical tests as novel lead structures with the aim of finding new antimalarial prototypes and lend support to the traditional use of the plants from which these compounds are derived.