53 resultados para Plant Roots


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The high performance liquid chromatography (HPLC) technique was applied to measure phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) activity in soybean (Glycine max L. Merril cv. BR16) roots. t-Cinnamate, the catalytic product of the PAL reaction was quantified at 275 nm by isocratic elution with methanol:water through an ODS(M) column. Comparative experiments were carried out with 1.0 mM ferulic acid, an inducer of PAL activity. The results suggest that liquid chromatography is a rapid and sensitive method to analyze PAL activity in non-purified extract.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The genus Actinocephalus comprises 25 species and is restricted to Brazil, occurring mainly in the Espinhaco Mountains of Minas Gerais and Bahia States. Previous anatomical studies have reported the occurrence of intracellular papillae in the Actinocephalus roots, without dealing with their ultrastructure and function. The purpose of this paper is to investigate the structure, the composition and the probable function of the intracellular papillae of Actinocephalus roots, based on light microscopy, transmission electron microscopy and histochemical tests. The intracellular papillae occurred in all root tissues, from the rhizodermis to the vascular cylinder; they presented different forms and sizes and, ultrastructurally, they corresponded to material deposited between the cell wall and the plasma membrane. The histochemical tests carried out were positive for cellulose, pectin and callose. The intracellular papillae are responses of the plant cells to the interaction with fungi. They work as a physical barrier restricting fungal penetration, and they may also favor the supply of water and nutrients to the plant, since they increase root absorption surface. This might explain why the species of Actinocephalus are among the tallest Eriocaulaceae despite their reduced radicular system and the nutritional deficiency of the soil in which they grow. (C) 2006 Elsevier Ltd. All rights reserved.

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De forma geral, as características do amido variam não somente com a planta de origem, mas também com o estádio de desenvolvimento desta. Neste trabalho objetivou-se avaliar a influência da época de plantio e estádio de desenvolvimento da planta de ahipa sobre as características físico-químicas das raízes, tamanho de grânulos do amido e suas propriedades viscográficas. Constatou-se influência do estádio de desenvolvimento da planta nas características físico-químicas das raízes e do amido, independentemente da época de plantio. A melhor época para o plantio de Pachyrhizus ahipa é outubro e a colheita deve ser feita no máximo com 9 meses, adotando-se o procedimento de retirada das flores a partir dos 3 meses.

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Zinc (Zn) uptake kinetics and root and leaf anatomy were studied in coffee trees grown in nutrient solutions with or without Zn. Leaves and roots were sampled and cuts were made in the medium part of the leaves and in root tips and observed under an optical microscope. Plants grown without Zn showed an increase in root and in root stele diameter. There was also an increase in epidermis thickness and in the cross-sectional area of the cortex and stele due to Zn deficiency, but the diameter of xylem vessels was decreased. An increase in root cortex and stele diameter provided for an increased surface for nutrient uptake. Accordingly, C(min) was decreased from 13.8 to 3.4 mu mol L(-1) and V(max) increased from 0.50 to 2.1 mu mol cm(-2) h(-1) .

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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A new 2,3,4,6-tetra-O-(3-nitropropanoyl)-O-β-D-glucopyranoside anomer was isolated from the roots of Heteropteris aphrodisiaca and characterized by spectroscopic methods. Activity against Staphylococcus aureus, Bacillus subtilis, Candida albicans, C. parapsilosis, C. krusei, and C. tropicalis was demonstrated.

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The plant-parasitic nematodes are responsible for serious injuries in roots and shoots of ornamental plants, reducing its beauty and consequently its economic value. This study aimed to ascertain the occurrence and distribution of plantparasitic nematodes through the analysis of the roots of ornamental and flowering plants at UNESP FCAV's landscape. The roots were collected from fifteen different species as follows: Anthurium andreannum, Rhododendron simsii, Impatiens walleriana, Calathea stromata, Cordyline terminalis, Dieffenbachia picta, Dracaena marginata, Ficus benjamina, Spathiphyllum ortgiesii 'Sensation', Spathiphyllum wallisi 'American Beauty' and 'Mini', Odontonema strictum, Portulaca grandiflora, Strelitzia reginae, Tradescantia zebrina and Tradescantia pallida. Samples of roots were processed. The plant-parasitic nematodes identified in the samples were: Meloidogyne sp. (Anthurium andreannum, Calathea stromata, Dieffenbachia picta, Ficus benjamina, Impatiens walleriana, Odontonema strictum, Portulaca grandiflora, Spathiphyllum ortgiesii 'Sensation'), Helicotylenchus dihystera (Calathea stromata, Dracaena marginata, Portulaca grandiflora, Spathiphyllum ortgiessi 'Sensation', Tradescantia pallida, Tradescantia zebrina), Tylenchus sp. (Anthurium andreannum, Calathea stromata, Cordyline terminalis, Dieffenbachia picta, Ficus benjamina, Rhododendron simsii), Aphelenchoides sp. (Dieffenbachia picta, Spathiphyllum ortgiesii 'Sensation', S. wallisi 'American Beauty'), Rotylenchulus reniformis (Cordyline terminalis, Dracaena marginata, Odontonema strictum), Pratylenchus sp. (Spathiphyllum ortgiesii 'Sensation', Spathiphyllum wallisi 'Mini'), Ditylenchus sp. (Spathiphyllum wallisi 'Mini'), Pratylenchus brachyurus (Tradescantia zebrina). The plant-parasitic nematodes weren't found in the roots of Strelitzia reginae.

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Background and aimsThe protocarnivorous plant Paepalanthus bromelioides (Eriocaulaceae) is similar to bromeliads in that this plant has a rosette-like structure that allows rainwater to accumulate in leaf axils (i.e. phytotelmata). Although the rosettes of P. bromelioides are commonly inhabited by predators (e.g. spiders), their roots are wrapped by a cylindrical termite mound that grows beneath the rosette. In this study it is predicted that these plants can derive nutrients from recycling processes carried out by termites and from predation events that take place inside the rosette. It is also predicted that bacteria living in phytotelmata can accelerate nutrient cycling derived from predators.MethodsThe predictions were tested by surveying plants and animals, and also by performing field experiments in rocky fields from Serra do Cipó, Brazil, using natural abundance and enriched isotopes of 15N. Laboratory bioassays were also conducted to test proteolytic activities of bacteria from P. bromelioides rosettes.Key ResultsAnalyses of 15N in natural nitrogen abundances showed that the isotopic signature of P. bromelioides is similar to that of carnivorous plants and higher than that of non-carnivorous plants in the study area. Linear mixing models showed that predatory activities on the rosettes (i.e. spider faeces and prey carcass) resulted in overall nitrogen contributions of 26·5 % (a top-down flux). Although nitrogen flux was not detected from termites to plants via decomposition of labelled cardboard, the data on 15N in natural nitrogen abundance indicated that 67 % of nitrogen from P. bromelioides is derived from termites (a bottom-up flux). Bacteria did not affect nutrient cycling or nitrogen uptake from prey carcasses and spider faeces.ConclusionsThe results suggest that P. bromelioides derive nitrogen from associated predators and termites, despite differences in nitrogen cycling velocities, which seem to have been higher in nitrogen derived from predators (leaves) than from termites (roots). This is the first study that demonstrates partitioning effects from multiple partners in a digestion-based mutualism. Despite most of the nitrogen being absorbed through their roots (via termites), P. bromelioides has all the attributes necessary to be considered as a carnivorous plant in the context of digestive mutualism. © 2012 The Author. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved.

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The aim of this study was to evaluate the effect of yacon (Smallanthus sonchifolius) (Poepp.& Endl.) on clinical parameters under diabetic conditions. The aqueous extract of yacon tuberous roots (YRAE; 0.76gfructankg-1 body weight) was prepared at the moment of each administration. Thirty-two male rats were divided into four groups (n=8): control group (C); group that received YRAE (Y); untreated diabetic group (DM1); and diabetic group treated with YRAE (Y-DM1). The diabetes mellitus was induced by streptozotocin (60mgkg-1 body weight). The animals from Y2 and Y-DM1 received YRAE by gavage, at 7-day intervals, for 30days. The aqueous extract of yacon roots decreased (p<0.05) the water and food intake in diabetic rats (Y-DM1). YRAE treatment reduced (p<0.05) glycaemia, total cholesterol, VLDL-c, LDL-c and triacylglycerol levels in diabetic rats (YRAE). HDL, urea and creatinine levels did not differ (p>0.05) between the Y and Y-DM1 groups. YRAE normalised alanine aminotransferase (ALT) activity, when comparing DM1 and Y-DM1 rats, but had no effect on lactate dehydrogenase activity (LDH). In conclusion, YRAE was sufficient for controlling water and food consumption, hyperglycaemia and dyslipidaemia, and promote the reduction of the ALT, suggesting a hepatoprotective effect in rats with STZ-induced DM1. © 2013 Elsevier Ltd.

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Brachiaria brizantha is considered one of the preferred fodders among farmers for having high forage yield and large production of root mass. The association of beneficial bacteria with these grasses can be very valuable in the recovery of the pasture areas with nutritional deficiency. With the aim of studying this possibility, we carried out the sampling of soil and roots of B. brizantha in three areas (Nova Odessa-SP, So Carlos-SP and Campo Verde-MT, Brazil). Seventy-two bacterial strains were isolated and used in tests to evaluate their biotechnological potential. Almost all isolates presented at least one positive feature. Sixty-eight isolates produced analogues of indole-3-acetic acid, ten showed nitrogenase activity when subjected to the method of increasing the concentration of total nitrogen (total N) in the culture medium and sixty-five isolates showed nitrogenase activity when subjected to acetylene reduction technique. The partial sequencing of 16S rRNA of these isolates allowed the identification of seven main groups, with the prevalence of those affiliated to the genus Stenotrophomonas (69 %). At the end, this work elected the strains C4 (Pseudomonadaceae) and C7 (Rhodospirillaceae) as promising organisms for the development of inoculants due to their higher nitrogenase activity.

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The invasive thistle Carduus nutans has been reported to be allelopathic, yet no allelochemicals have been identified from the species. In a search for allelochemicals from C. nutans and the closely related invasive species C. acanthoides, bioassay-guided fractionation of roots and leaves of each species were conducted. Only dichloromethane extracts of the roots of both species contained a phytotoxin (aplotaxene, (Z,Z,Z)-heptadeca-1,8,11,14-tetraene) with sufficient total activity to potentially act as an allelochemical. Aplotaxene made up 0.44 % of the weight of greenhouse-grown C. acanthoides roots (ca. 20 mM in the plant) and was not found in leaves of either species. It inhibited growth of lettuce 50%(I-50) in soil at a concentration of ca. 0.5 mg g(-1) of dry soil (ca. 6.5 mM in soil moisture). These values gave a total activity in soil value (molar concentration in the plant divided by the molarity required for 50 % growth inhibition in soil = 3.08) similar to those of some established allelochemicals. The aplotaxene I-50 for duckweed (Lemna paucicostata) in nutrient solution was less than 0.333 mM, and the compound caused cellular leakage of cucumber cotyledon discs in darkness and light at similar concentrations. Soil in which C. acanthoides had grown contained aplotaxene at a lower concentration than necessary for biological activity in our short-term soil bioassays, but these levels might have activity over longer periods of time and might be an underestimate of concentrations in undisturbed and/or rhizosphere soil.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)