Gabriela Silva Moura

Controle da antracnose em maracujá-amarelo por derivados de capim-limão (Cymbopogon citratus)

The yellow passion fruit is a major fruit crop in Brazil. The post-harvest preservation of yellow passion fruits has deserved great attention since the fruit is perishable and subject to a fast deterioration and incidence of pathogenic microorganisms. The aim of this work was to evaluate the in vitro antifungal activity of lemon grass derivatives on the mycelial growth, sporulation, spore germination and length of germ tubes of Colletotrichum gloeosporioides and the effect of essential oil, extract, hydrolate and citral lemon grass (Cymbopogon citratus) for control of anthracnose on the yellow passion fruits. The treatments for the in vitro assay were essential oil (OE) (0.5, 1, 5, 10, 15, 25, 50 and 60 µL mL-1), autoclaved crude aqueous extract (EAA), filtered crude aqueous extract (EAF), hydrolate and citral (1, 5, 10, 20 and 25%). For the in vivo assay the fruits were treated with: OE (0.025, 0.05 and 0.1%), hydrolate (5 and 10%), EAA (10%) and citral (0.1%). Distilled water was used as a control. The anthracnose incidence and severity were evaluated every three days. The in vitro test verified that the 4 evaluated derivatives of lemon grass inhibited the mycelial growth, sporulation and spore germination. The higher the concentration of the derivatives, the higher the inhibition, which for the mycelia growth reached 55.8; 54.5; 30.0 and 19.9% for OE, EAF, EAA and hydrolate, respectively. In vivo tests showed that the OE 0.1% and EAA 10% promoted a reduction in the anthracnose severity.

Atividade antimicrobiana e indutora de fitoalexinas do hidrolato de carqueja [Baccharis trimera (Less.) DC.]

Hydrolate is a product resulting from the extraction of a plant essential oil using steam distillation, which presents major metabolites of such plants in its composition. The objective of this work was to evaluate the phytoalexin induction and the antifungal and antibacterial activities of the Baccharis trimera hydrolate, in the concentrations of 1, 10, 25, 50, 75 and 100%. Phytoalexin induction was evaluated in etiolated sorghum mesocotyl and in soybean cotyledons. The antifungal activity was evaluated on the spore germination of Pseudocercospora vitis, Cercospora kaki and Hemileia vastatrix, while the antibacterial activity was evaluate on the Xanthomonas campestris pv. passiflorae, Erwinia carotovora and Bacillus subtilis multiplication. The hydrolate did not induce the phytoalexin synthesis in soybean, but it provided activity in sorghum in the concentration of 50% and above. Antibacterial activity occurred for the three isolates tested at the concentrations of 75 and 100%, with inhibition up to 87.9% for B. subtilis. The hydrolate showed no antifungal activity.

Induction of defense enzymes and control of anthracnose in cucumber by Corymbia citriodora aqueous extract

Secondary compounds of medicinal plants can activate defense mechanisms in plants against pathogens. The aqueous extract (AE) of Corymbia citriodora has shown that activity, but there is scarce information about the involved mechanisms of action. Therefore, this study aimed to evaluate the effect of AE on the induction of defense enzymes and protection of cucumber from Colletotrichum lagenarium. Thus, the AE, autoclaved or not, was evaluated for its capability of protecting and inducing peroxidases, polyphenoloxidases, chitinases and β-1.3-glucanases, and phenylalanine ammonia-lyase. Distilled water and acibenzolar-S-methyl (50 mg a.i. L) were used as controls. The effect of AE at the concentrations of 1, 5, 10, Franzener, G.; Schwan-Estrada, K.R.F.; Moura, G.S.; Kuhn, O.J.; Stangarlin, J.R. Induction of defense enzymes and control of anthracnose in cucumber by Corymbia citriodora aqueous extract. Summa Phytopathologica, v.44, n.1, p.10-16, 2018. 15 and 20% was also evaluated, as well as its local and systemic effect, and the effect of one or two applications. Pathogen inoculation or sample collection for determination of enzyme activity was performed at 72 hours after treatments. The AE reduced the severity of C. lagenarium and induced peroxidases and β-1.3-glucanases by 37.6, 67.2 and 122.7%, respectively. There was a reduction in the disease severity and an increase in peroxidases from the concentration of 5% AE. The latter showed only local effect and greater reduction in severity when two applications were performed. These results suggest the effect of AE in inducing resistance in cucumber and inducing peroxidases and β-1.3-glucanases.

Biodiversity of nematodes biological indicators of soil quality in the agroecosystems

ABSTRACT: Nematodes can be associated with the soil ecological condition, thus being associated with this sustainability condition of agricultural production. Studies of their diversity can be applied with the purpose of using them as bioindicators of environmental changes and the productive impacts. However, these organisms have been neglected in the agroecosystems, only assuming status of pathogen when their population is very high, with considerable losses in productivity. It is estimated that approximately 10% of the nematodes cause damage to plants, 25% are nematodes grouped into trophic levels of fungivores or fungal feeders, bacterivorous, and omnivores, according to the type of their food. In many cases it is not known the ratio of population level of the nematode with the level of damage in plants. For this reason, the use of pesticides and fertilizers is still part of the most common practices by farmers, causing loss of soil organic matter, soil erosion and groundwater contamination, in addition to an imbalance in the microbiote. The objective of this work was to make a brief review about the diversity of nematodes in the soil in the agroecosystems that can be used in studies of sustainability, as soil quality bioindicators. Several species of nematodes have the potential to be used as biological indicators of soil quality. In this sense, the knowledge and use of bioindicators by rural producers are important, in order to encourage practices of sustainable management systems that do not cause the soil biodiversity imbalance.

Postharvest conservation of yellow passion fruit from lemon grass (Cymbopogon citratus) derivatives

O maracuja-amarelo ( Passiflora edulis f. flavicarpa, Deg.) e uma das principais frutiferas cultivadas no Brasil. O manejo pos-colheita representa fator limitante para o maracuja-amarelo, pois ocorre aumento na suscetibilidade a doencas e a alteracoes fisico-quimicas no fruto. Objetivando aumentar a vida util de frutos do maracujazeiro, foi avaliado o efeito de produtos alternativos derivados de capim-limao ( Cymbopogon citratus ) sobre as caracteristicas fisico-quimicas de frutos do maracujazeiro em pos-colheita. Foram avaliados o oleo essencial (0,025, 0,05 e 0,1%), extrato aquoso (10%), hidrolato (5 e 10%) e citral (0,1%) em delineamento inteiramente casualizado com quatro repeticoes. Foram avaliados o indice de murchamento, rendimento de suco, reducao de massa, diâmetros longitudinal e equatorial, coloracao da casca, solidos soluveis totais, acucares redutores, acucares nao redutores, acucares totais, pH, acidez total titulavel, vitamina C e a relacao solidos soluveis totais e acidez total titulavel. Os frutos de maracuja-amarelo foram tratados apos a colheita e as avaliacoes foram realizadas durante 15 dias de armazenamento dos frutos sob condicoes de temperatura ambiente. Os derivados de C. citratus promoveram alteracoes nos atributos fisico-quimicos dos frutos de maracuja-amarelo. Melhores resultados foram obtidos com oleo essencial a 0,1% que promoveu maior rendimento de suco e menor perda de peso nos frutos tratados, representando alternativa na conservacao pos-colheita. O produto citral 0,1% mostrou efeito fitotoxico, comprometendo os atributos fisico-quimicos relacionados a maturacao e qualidade dos frutos. Abstract The yellow passion fruit ( Passiflora edulis f. flavicarpa , Deg.) is one of the major fruit crops in Brazil. The post-harvest management is a limiting factor for the culture because there is an increase in susceptibility to diseases and physicochemical changes in the fruit. With the objective of increasing the shelf life of passion fruits, it was evaluated the effect of alternative products derived from lemon grass ( Cymbopogon citratus ) on the physicochemical characteristics of passion fruit in postharvest. It was evaluated the essential oil (0.025, 0.05 and 0.1%), aqueous extract (10%), hydrolate (5 and 10%) and citral (0.1%) in a completely randomized design with four replications. It was also evaluated the rate of wilting, the juiciness, mass reduction, longitudinal and equatorial diameters, peel color, soluble solids, reducing sugars, non-reducing sugars, total sugars, pH, titratable acidity, vitamin C and the relation between total soluble solids and titratable total acidity. The fruits of passion fruit were treated after harvest and assessments were performed during 15 days of storage of the fruits under ambient temperature conditions. The lemon Grass derivatives promoted changes in physicochemical attributes of the passion fruits. Best results were obtained with 0.1% essential oil that promoted higher juice yield and less weight loss in the treated fruits, representing alternative for the postharvest conservation of the fruits. The citral product showed phytotoxic effect, affecting the physical and chemical attributes related to maturation and fruit quality.

Ocorrência de Sclerotium rolfsii em Rumex acetosa no Paraná

pertence a familiaPolygonaceae e apresenta folhas verdes arredondadas, com consistenciaque lembra agriao. Nos ultimos anos essa planta tem merecido maioratencao por suas propriedades nutricionais e medicinais. Algunstrabalhos mostraram que as folhas e, principalmente, raizes, saoimportantes fontes do anti-oxidante resveratrol. Nos meses de abril emaio de 2009, plantas de