Erik Nunes Gomes

Enraizamento de estacas apicais, medianas e basais de Piper aduncum L. em diferentes substratos

Piper aduncum L. (Piperaceae) is an aromatic species native from Tropical Americas. The elevated dillapiole content in its essential oil attributes great economic potential to the species, due to its proven insecticidal action against important agricultural pests. The domestication and cultivation of this species, seeking the standardization of the essential oil quality, goes through the stage of plant propagation, which presents scarce technical and scientific information. Thus, the objective of this study was to evaluate the rooting of stem cuttings collected from the apical, median and basal positions of P. aduncum plagiotropic branches, in sieved soil, commercial substrate (composed of pine bark, peat, expanded vermiculite and enriched with macro and micronutrients), and vermiculite of medium granulometry. The cuttings were kept under intermittent misting for 45 days until the experimental evaluation. Higher rooting percentages were observed in apical cuttings (17.4%) when compared to basal ones (6.9%). There were also higher number, length and fresh mass of roots in apical cuttings. The substrate did not influence the rooting of P. aduncum stem cuttings.

Chemical composition of Piper gaudichaudianum essential oil and its bioactivity against Lucilia cuprina (Diptera: Calliphoridae)

Abstract Piper gaudichaudianum grows abundantly throughout the Brazilian Atlantic Forest. Essential oil extracted from this species has been reported to have larvicidal properties. The aim of the study was to characterize the essential oil (EO) of P. gaudichaudianum and its insecticide activity on the third instar larvae (L3) of Lucilia cuprina under laboratory conditions. Groups of 20 L3 were placed on filter paper impregnated with increasing concentrations of 2.5–30% (v/v), equivalent to 0.39–4.77 μL/cm2, solubilized in ethanol or acetone. The toxicity was determined by L3 mortality after 6, 24 and 48 h after contact. P. gaudichaudianum EO was also characterized using CG/MS. Lethal concentrations of 50% (LC50) 24 and 48 h after EO exposure were found to be 3.69 and 2.19 when solubilized in ethanol and 9.14 and 6.05 μL/cm2 when solubilized in acetone, respectively. The major compounds were germacrene B, δ-cadinene, γ-elemene, (Z)-cariophyllene, α-copaene, (E)-cariophyllene, α-calacorene, α-humulene and (E)-nerolidol. The study demonstrated the significant biological activities of P. gaudichaudianum EO (PGEO) compounds against L. cuprina.

Enraizamento de estacas de erva-baleeira em função de diferentes concentrações de ácido indol butírico e número de folhas

Varronia curassavica Jacq., black sage, is a medicinal plant with commercial interest due its anti-inflammatory properties. This species can be propagated by seeds, via vegetative propagation enabling the achievement of more uniform crops in relation to the agronomic and phytochemicals aspects. Thus, the present study aimed to evaluate the effect of different concentrations of indole butyric acid (IBA) and different leaf numbers in softwood stem cuttings of black sage plants. The experiment was conducted in august (winter season) in a factorial arrangement 3x2, with three different concentrations of IBA (0, 1500 and 3000 mg L-1) and two numbers of leaves (two leaves or one leaf). The experiment was conducted in a greenhouse under intermittent mist conditions. At 60 days after planting, the rooting percentage, number of roots per cutting, length of the three longest roots, percentage of cuttings with callus, percentage of live cuttings without roots nor callus, percentage of dead cuttings and percentage of cuttings with shoots were evaluated. There were significant differences for number of roots per cutting, which was higher at a concentration of 3000 mg L-1 compared to treatment without application of IBA (32.5%), and for percentage of cuttings with callus (15.0%), also higher were cuttings with two leaves at a concentration of 3000 mg L-1 IBA. For other factors there were no statistical differences between treatments. We conclude that the different number of leaves and IBA concentrations had little influence on the adventitious roots, mainly due to the winter season.