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ABSTRACT: This study o evaluated growth, leaf gas exchange and arbuscular mycorrhizal fungi root colonization in three medicinal plant species under different irradiance intensities. Fridericia chica (Bonpl.) L.G.Lohmann, Mikania laevigata Sch.Bip. ex Baker and Varronia curassavica Jacq. were propagated by cutting and cultivated for 120 days in artificially shaded environments using black shade-type screens, obtaining four irradiance levels: 100%, 70%, 50% and 30%. The experimental design was completely randomized in a 3 x 4 factorial scheme (three plant species and four irradiation levels) with seven replicates. The three medicinal species showed higher liquid assimilation, mass growth and arbuscular mycorrhizal fungi root colonization rates when exposed to environments with 70% light availability. In relation to physiological responses, V. curassavica presented higher photosynthetic rate, stomatal conductance and transpiration when submitted to 70% irradiance, being able to be cultivated in more open environments with higher irradiation levels. Conversely F. chica and M. laevigata presented shade tolerance characteristics. At the initial growth phase, the results obtained can be used as indicators to recommend the ideal cultivation environment for these species in agroforestry systems.

Fridericia chica (Bonpl.) L. G. Lohmann has medicinal properties and potential for commercial cultivation; however, the propagation characteristics of this species have been poorly evaluated. This study aimed to analyze the length of cuttings, indolebutyric acid (IBA) doses and substrates containing different proportions of cocoa shell in F. chica cuttings. Two experiments were carried out. In the first one, the treatments were basal cuttings of 10 cm and 20 cm in length and four IBA concentrations (0 mg L-1, 2,000 mg L-1, 4,000 mg L-1 and 6,000 mg L-1). In the second experiment, substrates obtained from five proportions of cocoa shell (CS) and expanded vermiculite (EV) compost were tested: 100 % CS; 100 % EV; 50 % CS + 50% EV; 30 % CS + 70 % EV; 70 % CS + 30 % EV. The rooting percentage, sprouting height and dry biomass production were evaluated. The production of F. chica seedlings can be performed by basal cuttings with 20 cm in length, which allow achieving a rooting rate of 91 %. The ideal IBA dose to obtain a maximum sprout length is 3,600 mg L-1. Mixtures composed of 50 % CS + 50 % EV and 30 % CS + 70 % EV were the best substrates for the production of F. chica seedlings.

The use of organic composts and the inoculation of arbuscular mycorrhizal fungi (AMF) are management alternatives in organic production systems. This study aimed to evaluate the effect of AMF inoculation (Acaulospora scrobiculata, Acaulospora colombiana and without inoculation) and organic compost of cacao bark (0 g dm-3, 5 g dm-3, 10 g dm-3, 20 g dm-3 and 30 g dm-3) on the mycorrhizal efficiency and nutrient uptake, in 'Morada' soursop seedlings. The experimental design was completely randomized, in a 3 x 5 factorial arrangement (AMF x organic compost), with four replicates. A higher mycorrhizal efficiency was observed for the A. colombiana isolate, with the addition of 0 g dm-3, 5 g dm-3 and 10 g dm-3 of organic compost to the soil, in relation to the A. scrobiculata isolate, which differed statistically at the doses of 20 g dm-3 and 30 g dm-3 of organic compost. The AMF inoculation promotes increases in the N, P, K, Zn, Cu, Fe and Mn contents, when compared to plants without inoculation. The organic compost exerts an effect on the inoculation, mainly on the absorption of P. The AMF inoculation, together with the organic fertilization, promotes the growth and nutrition of seedlings.

The application of growth promoting substances, such as humic acids, during the formation of fruit seedlings can benefit growth and increase the plant nutrient uptake and translocation. This study aimed to evaluate the effect of the application of humic acid doses (0 mg L-1, 2 mg L-1, 20 mg L-1, 40 mg L-1 and 200 mg L-1) extracted from vermicompost of sugarcane filter cake on the nutrient uptake of seminal mangosteen (Garcinia mangostana L.) seedlings. The experimental design was completely randomized, with 7 replicates for each treatment. The application of humic acids promoted curvilinear increments with quadratic rates for N, P, K, Ca, Mg and S contents from shoots and roots, as well as quadratic increments in the Zn and Mn uptake by shoots. The application of humic acids increased the chlorophyll a and chlorophyll b contents and reduced the carotenoid content. Overall, the regression analysis demonstrated that a dose of 150 mg L-1 is capable of providing the most adequate nutrient uptake by plants, and should be recommended for the production of mangosteen seedlings. Humic acids from vermicompost can provide a better nutrition in mangosteen seedlings at the nursery stage.

ABSTRACT: Medicinal plants are generally commercialized dried. However, temperatures used in their drying processes may interfere with the content and chemical composition of their essential oils. The Lippia origanoides possesses thymol in the essential oil that is stored in glandular trichomes. Thymol is a major component of economic importance in the chemical and pharmaceutical industry. The objective of this study was to evaluate the effect of the drying temperatures of L. origanoides leaves regarding trichome integrity, content, and chemical composition of the essential oil. The experimental design was completely randomized with four treatments defined by oven drying temperatures (40, 50, 60, and 70ºC) and four replications. Essential oil was extracted by hydro distillation and the essential oil contents were determined (%). Chemical composition of the oil was analyzed by gas chromatography coupled to mass spectrometry. Scanning electron microscopy was carried out to determine trichome integrity. Drying the L. origanoides leaves in a forced ventilation oven at 40°C minimized the loss of extracted essential oil content (17.5g kg-1) and relative thymol percentage. Leaves dried at the temperatures of 60 and 70ºC exhibited a higher percentage of ruptured trichomes and reduced essential oil content to 13.7g kg-1 and 11.8g kg-1, respectively.

Para avaliar o efeito de substratos e da adubação fosfatada sobre a produção de mudas de cacaueiro, bem como definir doses recomendáveis e nível crítico foliar de P, fez-se um experimento fatorial 5 x 5 + 1: cinco substratos (misturas de fibra de coco (FC) e Plantmax florestal estaca®), cinco doses de P no plantio (de 0 a 800 mg dm-3) e um tratamento adicional (P aplicado aos 30 dias). As parcelas iniciais e úteis continham, respectivamente, 27 estacas e 12 mudas (uma estaca/muda por tubete). A partir do 62º dia, aplicaram-se adubações semanais com N e K, e aos 120 dias, com P (20 mg dm-3), em todos os tratamentos. Aos 150 dias foram avaliados: diâmetro, altura, área foliar, massa de matéria seca da parte aérea e das raízes (finas e grossas), concentração e conteúdo de nutrientes na planta. A mortalidade das mudas não foi influenciada pelos tratamentos. A adubação com P em cobertura aumentou sua disponibilidade e sua absorção, mas não o crescimento das mudas. As variáveis biométricas e nutricionais responderam aos tratamentos, sendo os melhores resultados obtidos com 30 a 55 % de FC e doses de P entre 136 e 275 mg dm-3. O nível crítico foliar de P foi de 1,75 g kg-1.

ABSTRACT: Desert rose (Adenium obesum) is a succulent plant that is native to the Arabian Peninsula. It has great commercial value with exuberant structure and flowering. It can be propagated by seeds to ensure maximum development of the caudex. Despite its high economic value, studies on its propagation are still required. The aim of this study was to evaluate seed germination performance and seedling development of desert rose seedlings in different substrates. Treatments comprised five different substrate compositions: S1 (Soil), S2 (Sand), S3 (Carolina Soil commercial substrate), S4 (Sand + Carolina Soil), and S5 (Soil+ Carolina Soil). The following were evaluated using uni- and multi-variate approaches: germination, first count, germination speed index, caudex diameter, number of leaves, seedling length, root length, shoot length, and fresh mass and dry mass. Sand is the ideal substrate for the germination of A. obesum seeds, while for forming seedlings, mixtures of the Carolina Soil commercial substrate with sand or soil should be used.

ABSTRACT Regularly spaced earth mounds called “murundus” are scattered in several landscapes in the semi-arid region of Brazil. Although recent evidence indicates that termites are involved in the building of murundus, the contribution of these insects to soil-forming processes in those structures remains poorly understood. In this study, we tested a set of hypotheses to examine whether there are consistent evidence for suggesting the participation of termites in the formation of murundus soils. Morphological and physicochemical features of murundus were compared with adjacent soil profiles in the inter-mounds surface and one epigeic nest built by one species of Syntermes Holmgren. The murundus soils had a more clayey texture, higher contents of nutrients (C, N, P, K, Ca, and Mg) and organic matter compared with adjacent soils. We identified a set of recent and ancient traces inside the murundus that reveals the intense building activity of termite colonies (e.g., galleries, tunnels, and royal chambers), confirming that these structures are not only occupied by these insects but also built-up by them. Taken together, our results provide hard evidence that the long-term activity of mound-building termites was the hierarchically dominant process in producing murundus structures in the semi-arid region of Brazil. Based on available empirical data, we propose an explanatory model on how that construction process may have taken place.

ABSTRACT: The use of management zones has ensured yield success for numerous agricultural crops. In spite of this potential, studies applying precision agricultural techniques to cacao plantations are scarce or almost nonexistent. The aim of the present study was to delineate management zones for cacao crop, create maps combining soil physical properties and cacao tree yield, and identify what combinations best fit within the soil chemical properties. The study was conducted in 2014 on a cacao plantation in a Nitossolo Háplico Eutrófico (Rhodic Paleudult) in Bahia, Brazil. Soil samples were collected in a regular sampling grid with 120 sampling points in the 0.00-0.20 m soil layer, and pH(H2O), P, K+, Ca2+, Mg2+, Na+, H+Al, Fe, Zn, Cu, Mn, SB, V, TOC, effective CEC, CEC at pH 7.0, coarse sand, fine sand, clay, and silt were determined. Yield was measured in all the 120 points every month and stratified into annual, harvest, and early-harvest cacao yields. Data were subjected to geostatistical analysis, followed by ordinary kriging interpolation. The management zones were defined through a Fuzzy K-Means algorithm for combinations between soil physical properties and cacao tree yield. Concordance analysis was carried out between the delineated zones and soil chemical properties using Kappa coefficients. The zones that best classified the soil chemical properties were defined from the early-harvest cacao yield map associated with the clay or sand fractions. Silt content proved to be an inadequate variable for defining management zones for cacao production. The delineated management zones described the spatial variability of the soil chemical properties, and are therefore important for site-specific management in the cacao crop.