ABSTRACT
The objective of this study was to evaluate the relative competitive ability of soybean with different development stages of hairy fleabane. Two experiments were conducted in greenhouse, in a completely randomized design. In the experiment it was tested soybean and hairy fleabane competition at different stage of development (rosette and 15 cm height) at the proportions 100:0, 75:25, 50:50, 25:75 and 0:100, and total plant population was 315 plant m-2. The variables evaluated were plant height, leaf area, and shoot dry matter (leaves and stems). Competitive analysis was performed by diagrams and interpreting the competitiveness index. The soybean has greater competitive ability that horseweed for both development stages. The intraspecific competition is more intense for soybean when in hairy fleabane rosette stage, and the competitive relations are equivalent between soybean and hairy fleabane of 15 cm tall. The both hairy fleabane stages were injured in the soybeans competition.(AU)
O objetivo deste trabalho foi avaliar a habilidade competitiva relativa da cultura da soja com buva de diferentes estádios de desenvolvimento. Foram realizados dois experimentos em casa de vegetação, em delineamento inteiramente casualizado. Os experimentos testaram a competição de soja e buva (estádio roseta e plantas com 15 cm de estatura) nas proporções de 100:0, 75:25, 50:50, 25:75 e 0:100, com população equivalente a 315 plantas m-2. As variáveis avaliadas foram estatura, área foliar e matéria seca da parte aérea (folhas e caule). A análise da competitividade foi realizada por aplicação de diagramas e interpretações dos índices de competitividade. Os resultados da competição da soja com buva de diferentes estádios de desenvolvimento evidenciam que o cultivar de soja BRS Estância RR, em geral, possui mais habilidade competitiva que a buva, independentemente do estádio de desenvolvimento. A competição intraespecífica é mais intensa para a cultura quando em competição com buva em estádio de roseta, enquanto para a soja com buva de 15 cm as relações de competição se equivalem. O desenvolvimento da buva é prejudicado na competição com a soja.(AU)
Subject(s)
Glycine max , Conyza , Growth and DevelopmentABSTRACT
The interference of glyphosate resistant hairy fleabane (Conyza bonariensis) has caused yield losses in soybean crop. Knowledge of the economic threshold is an important aspect for the economic management of resistant weeds. Because of it, the interference of the glyphosate resistant hairy fleabane density on the soybean yield loss was evaluated, as well as to estimate the economic threshold. Two experiments were conducted to verify the effect of different weed densities on the yield of two soybean cultivars (BRS Estância and BMX Turbo). Weed density ranged from 0 to 124 plants m-2. The yield of the BRS Estância decreased by 1.4% to the increase of one single plant, while for the BMX Turbo the loss was 25.9%. Soybean yield and economic threshold were lower for the BMX Turbo cultivar compared to the cultivar BRS Estância, which can be attributed to the genotype, competitive ability, weed development stage and/or environment. Increases in crop yield expectation, soybean price and herbicide efficiency reduce the economic threshold, indicating that the adoption of control measures should be taken when the weed density is low. Due to the high cost of hairy fleabane control, it is only feasible at high densities.(AU)
A interferência de plantas de buva (Conyza bonariensis) resistente ao herbicida glyphosate tem causado perdas de produtividade na cultura da soja. O conhecimento do nível de dano econômico é um importante fator para o manejo econômico de plantas daninhas resistentes na cultura da soja. Para isso, foi avaliada a interferência da densidade de buva resistente ao glyphosate sobre a perda de rendimento da soja, bem como estimado o nível de dano econômico. Dois experimentos foram conduzidos para verificar o efeito de diferentes densidades da planta daninha sobre a produtividade de dois cultivares de soja (BRS Estância e BMX Turbo). As densidades de buva variaram de 0 a 124 plantas m-2. A produtividade do cultivar BRS Estância reduziu 1,4% ao aumento de uma planta, enquanto para o cultivar BMX Turbo a perda foi de 25,9%. A produtividade da soja e o nível de dano econômico foram menores para o cultivar BMX Turbo, em comparação com o cultivar BRS Estância, o que pode ser atribuído ao genótipo, à habilidade competitiva, ao estádio de desenvolvimento da buva e/ou a ambiente. Aumentos na expectativa de produtividade da cultura, no preço da soja e na eficiência dos herbicidas reduzem o nível de dano econômico, indicando que a adoção de medidas de controle deve ser tomada quando a população de buva é baixa. Em função do elevado custo de controle da buva, este somente é viável em altas densidades.(AU)
Subject(s)
Glycine max , Conyza , Herbicide Resistance , Plant Weeds , EfficiencyABSTRACT
ABSTRACT Essential oils are pharmacologically active and unexplored compounds. The inhibitory properties of essential oils from Baccharis dracunculifolia, Conyza bonariensis, Tithonia diversifolia and Ambrosia polystachya were evaluated in the coagulation and fibrinogenolysis induced by snake venoms. The essential oil from Conyza bonariensis extended the clotting time of Lachesis muta from 52.2 to 115.2 seconds and that of Bothrops moojeni from 108.3 to 2340.0 seconds, when pre-incubated with the venoms. The longest clotting times for Bothrops atrox venom were observed after incubation with the essential oils from Conyza bonariensis and Tithonia diversifolia: the times increased from 100.8 to 264.0 and 227.7 seconds, respectively. The prior incubation of the essential oils with plasma and subsequent addition of Lachesis muta venom resulted in a pro-clotting effect. The oils from Ambrosia polystachya and Baccharis dracunculifolia caused 100% of inhibition on the fibrinogenolysis induced by Bothrops moojeni and Lachesis muta venoms (the oils were previously incubated with the venom). The results indicate that the essential oils show promise as adjuvants for the treatment of snakebites.
ABSTRACT
The present report is a comparative investigation of two Conyza species growing wild in Egypt namely, Conyza dioscoridis (L.) Desf. and Conyza bonariensis (L.) Cronquist. It comprises a genetic and chemical characterization of the plants, as well as an evaluation of their biological activities. The DNA fingerprints of the two species were established based on a polymerase chain reaction (PCR) procedure using ten decamer primers. Further characterization of the plants was performed via determination of pharmacopoeial constants, phytochemical screening and estimation of phenolic content (total phenolics, tannins and flavonoids). The ethanol (70%) extracts of C. dioscoridis (EECD) and C. bonariensis (EECB) were subjected to acute toxicity study to determine their LD50; the anti-inflammatory, antimicrobial and cytotoxic activities were then evaluated. Screening for potential cytotoxicity was carried out both by Brine Shrimp Lethality Test and Sulphorodamine-B assay on three human cell lines viz., breast carcinoma (MCF7), colorectal carcinoma (HCT116) and cervical carcinoma (HELA) cell lines. The DNA profiling revealed a similarity index of 88.89% between the investigated species. The variability observed among the pharmacopoeial constants constitute a valuable differential criterion; the total ash, acid insoluble ash, water soluble ash and crude fiber values obtained for C. bonariensis exceeded (17, 5, 10 and 3.5%, respectively) those for C. dioscoridis; meanwhile, the moisture content was higher (10%) in the latter. The phytochemical screening of EECD and EECB revealed the presence of flavonoids, steroids, terpenoids and tannins in both species. Estimation of phenolic contents (total phenolics, tannins and flavonoids expressed as gallic acid, tannic acid and rutin equivalents, respectively) showed that EECD contains higher amounts of all these constituents when compared to EECB (1.17 vs. 0.96 mg/g, total phenolics; 2.43 vs. 1.83 mg/g, tannins and 0.62 vs. 0.29 mg/g, flavonoids). EECD and EECB were found to be safe (LD50 upto 0.5g/kg). Throughout evaluation of the antimicrobial activity against a set of microbial strains and potential cytotoxicity against MCF7, EECD appeared more efficient (MIC: 200-400 μg/ml and IC50: 2.97 μg/ml, respectively); meanwhile, the effect of EECB was more significant on HCT116 and HELA (IC50: 21 and 5.4 μg/ml, respectively). Results of in-vivo assessment of the anti-inflammatory activity showed that the inhibitory effect of EECD was more prominent than that of EECB (74.20% vs. 59.0%). However, the effect of the extracts was inversed in the Brine Shrimp Lethality test (30% vs. 40% lethality, respectively).
ABSTRACT
Introducción: la especie Conyza bonariensis (L.) Cronquist, comúnmente llamada canilla de venado, es de origen americano. Objetivos: contribuir al estudio farmacológico y toxicológico de los extractos alcohólicos y a la evaluación química del aceite de hojas de C bonariensis de Ecuador. Métodos: se emplearon 2 tinturas a 50 por ciento con etanol a 70 y 90 por ciento de hojas secas. Se realizó un estudio fitoquímico a través del sistema acoplado de cromatografía gaseosa-espectrometría de masas, se determinó el efecto antimicótico mediante inhibición de dilución en placa con siembra en superficie por diseminación, y antiinflamatorio en el modelo de edema de la oreja inducido por aceite de Croton en ratones albinos de la línea OF1. Resultados: el tamizaje fitoquímico mostró presencia de aceites esenciales, triterpenos-esteroides, compuestos fenólicos, flavonoides, quinonas, antocianidinas, saponinas y compuestos reductores. Se determinó estructuras a 32 componentes del aceite esencial extraído de las hojas y el sesquiterpeno: trans-b-farneseno resultó el componente mayoritario con 70,82 por ciento, este compuesto se informa por primera vez en esta especie. El extracto hidroalcohólico (25 µL a cada lado de las orejas tratadas) inhibió significativamente la inflamación comparado con bencidamina. Conclusiones: los extractos hidroalcohólicos mostraron efecto antiinflamatorio en las condiciones experimentales del estudio y se determinó la composición química del aceite de hojas de C. bonariensis
Introduction: the Conyza bonariensis (L) Cronquist species, usually called deer shinbone is of American origin. Objectives: to contribute to the pharmacological and toxicological study of alcoholic extracts and to the chemical assessment of C. bonariensis leaf oil from Ecuador. Methods: two 50 percent tinctures of 70 percent and 90 percent ethanol content in dry leaves were used. A phytochemical study was conducted by an combined system of mass spectrometry and gas chromatography; the amniotic effect was determined using plate dilution inhibition with surface culturing by dissemination, and the anti-inflammatory effect in the Croton oil induced ear edema model in OF1 line albino mice. Results: the phytochemical screening showed the presence of essential oils, triterpene-steroids, phenolic compounds, flavonoids, quinones, anthocyanidines, saponins and reducing compounds. The structures of 32 essential oil components extracted from the leaves were identified along with and the sesquiterpene trans-b-farnesene that was the major component (70.82 percent), this compound is reported for the first time in this species. The hydroalcoholic extract (25 µL on each side of the treated ears) significantly inhibited inflammation compared to benzidamine. Conclusions: hydroalcoholic extracts showed anti-inflammatory effect in the experimental conditions of the study and the chemical composition of C. bonariensis leaf oil was identified