992 resultados para LEAF GROWTH
Resumo:
This work aimed to evaluate the effect of different concentrations of IBA (indolbutyric acid) in the rooting and growth of Eucalyptus urophylla cuttings. The experimental design used was the randomized blocks, in factorial with an arrangement of split plots, with three concentrations of IBA (2.000; 5.000 and 8.000 mg L(-1)), two ways of the application of plant gowth regulators (paste and powder), and three period of evaluations (30, 45 and 60 days). The experiment was carried out in the Farm Buriti de Prata, an entreprise property of Souza Cruz, in the city of Prata - MG in 2003. After the preparation of the cuttings, patterned in 10 cm of length and 0.8 cm of diameter, those were immersed in mixtures of IBA for 10 seconds, in the forms of dry powder and paste and than planted in plastic tubes contening Plantmax substrate with vermiculite. The cuttings were transported to greenhouse with controled humidity, where they remained for 60 days. The variables studied were: height of plant in the 30(th), 45(th) and 60(th) days after seeding; fresh mass of the aerial part and roots. The IBA applied in powder form as well as in paste form, resulted in an greater seedling growth. To the 60 days, the seedlings presented greater growth, being significantly superior to the heights measured in other times of evaluation. The application of 2.000 mg L(-1) and 5,000 mg L(-1) resulted in significant increases on weight of fresh mass of the aerial part and root system.
LEAF AREA REDUCTION IN CORN GROWN IN A TROPICAL REGION OF BRAZIL AND ITS EFFECTS ON AGRONOMIC TRAITS
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Global climate change may reduce leaf area in crop plants due to factors such as increasing occurrence of pests and diseases. The aim of this work was to estimate the impact of leaf area reduction on agronomic traits in corn. An experiment simulating leaf area reduction was carried out in a tropical region of Brazil. The agronomic performance of corn plants was evaluated at different percentages of leaf loss. It was observed that leaf area reductions over 41.01% significantly harm yield, mass of 1000 grains, cob density, and stem and root quality Crop improvement programs should take into account the development of genotypes resistant to factors that cause leaf area reduction in tropical crops.
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To determine the effect of sensor placement on the performance of a disease-warning system for sooty blotch and flyspeck (SBFS), we measured leaf wetness duration (LWD) at 12 canopy positions in apple trees, then simulated operation of the disease-warning system using LWD measurements from different parts of the canopy. LWD sensors were placed in four trees within one Iowa orchard during two growing seasons, and in one tree in each of four orchards during a single growing season. The LWD measurements revealed substantial heterogeneity among sensor locations. In all data sets, the upper, eastern portion of the canopy had the longest mean daily LWD, and was the first site to form dew and the last to dry. The lower, western portion of the canopy averaged about 3 It less LWD per day than the top of the canopy, and was the last zone where dew formed and the first to dry off. On about 25% of nights when dew occurred in the top of the canopy, no dew formed in the lower, western canopy. Intracanopy variability of LWD was more pronounced when dew was the sole source of wetness than on days when rainfall occurred. Daily LWD in the upper, eastern portion of the canopy was slightly less than reference measurements made at a 0.7-m height over turfgrass located near the orchard. When LWD measurements from several canopy positions were input to the SBFS warning system, timing of occurrence of a fungicide-spray threshold varied by as much as 30 days among canopy positions. Under Iowa conditions, placement of an LWD sensor at an unobstructed site over turfgrass was a fairly accurate surrogate for the wettest part of the canopy. Therefore, such an extra-canopy LWD sensor might be substituted for a within-canopy sensor to enhance operational reliability of the SBFS warning system.
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Pseudocercospora griseola (Sacc.) Crous &. Braun is a widespread fungal phytopathogen that is responsible for angular leaf spot in the common bean (Phaseolus vulgaris L.). A number of fungal phytopathogens have been shown to harbour mycoviruses, and this possibility was investigated in populations of Pseudocercospora griseola. The total nucleic acid extracts of 61 fungal isolates were subjected to agarose gel electrophoresis. Small fragments (800-4800 bp) could be identified in 42 of the samples. The presence of dsRNA in isolate Ig838 was confirmed by treatment of total nucleic acid with DNase, RNase A, and nuclease S I. Transmission electron microscopy revealed the presence of viral-like particles 40 nm in diameter in the mycelia of 2 fungal isolates, namely 29-3 and Ig838. The transmission of dsRNA by means of conidia was 100% for isolate 29-3, but there was loss of 1-6 fragments of dsRNA in monosporic colonies of isolate Ig848. Cycloheximide treatment failed to inhibit the mycovirus in isolate 29-3, but proved efficient in the elimination of the 2.2, 2.0, 1.8, 1.2 and 1.0 kb fragments in 2 colonies of isolate Ig848. The occurrence of a mycovirus in Pseudocercospora griseola was demonstrated for the first time in the present study.
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Most researches that have been done until today about the beneficial effects of hariparoha (Pothomorphe umbellata L. Miq) have been done with root extract of this species, but the use in large scale would compromise the sustainable exploration of this natutral resource. In this sense, the utilization of pariparoha leaves, substituting the roots, in the cosmetic industry does not put in risk the existence of the species. In this work the concentration of 4-nerolidyl-cathecol (4-NC) in leaf extract was determined by the analytical methodology validated in our laboratory. The concentration of 4-NC in leaf extract was around 30% less than that of root extract, obtained in the same way. Concerning the study of the photostability of a leaves extract solution containing 4-NC did not demonstrate meaningful alterations in the spectrometry, profile after 2 hours of exposure under UVB radiation, showing its stability under this conditions. Metalloproteinases (MMPs) cure endopeptidases that are zinc-dependent, involved in remodeling extracellular matrix (ECM), that are important in the appearance of typical photoaging wrinkles. In this work the capacity of leaf extract of P. umbellata to inhibit MMP-2 and 9 activities of hairless mouse skin in vitro by zymography gel was also evalutated. The leaf extract (0,1 mg/mL) inhibit in 80% activity of this enzymes, according to the densitometric zymography evaluation.
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Background: Statins induces cell cycle arrest, apoptosis, reduction of angiogenic factors, inhibition of the endothelial growth factor, impairing tissue adhesion and attenuation of the resistance mechanisms. The aim of this study was evaluate the anti tumoral activity of simvastatin in a B16F10 melanoma-mouse model. Methods: Melanoma cells were treated with different concentrations of simvastatin and assessed by viability methods. Melanoma cells (5 x 10(4)) were implanted in two month old C57Bl6/J mice. Around 7 days after cells injection, the oral treatments were started with simvastatin (5 mg/kg/day, p.o.). Tumor size, hematological and biochemical analyses were evaluated. Results: Simvastatin at a concentration of 0.8 mu M, 1.2 mu M and 1.6 mu M had toxic effect. Concentration of 1.6 mu M induced a massive death in the first 24 h of incubation. Simvastatin at 0.8 mu M induces early cell cycle arrest in G0/G1, followed by increase of hypodiploidy. Tumor size were evaluated and the difference of treated group and control, after ten days, demonstrates that simvastatin inhibited the tumor expansion in 68%. Conclusion: Simvastatin at 1.6 mu M, presented cytototoxicity after 72 h of treatment, with an intense death. In vivo, simvastatin being potentially useful as an antiproliferative drug, with an impairment of growth after ten days.
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Background Excess of terminal hair can be defined as excessive hair that appears in male-like pattern in women. Some experts consider this condition as a result of an atypical relationship between levels of circulating androgens and sensitivity of androgen receptors in hair follicles to circulating androgens. Aims The aim of this research work was to evaluate the efficacy of a topical treatment for suppressing terminal hair growth of a cream containing 6.0% of the Stryphnodendron adstringens bark extract. Study design and subjects Study was randomized, double-blind and placebo-controlled. Subjects with excess of terminal hair were randomized to placebo and to the active treatment (cream with 6.0% of the extract). Evaluation was performed before and after 6 months, and subjects were photographed in each time. Clinical examination was carried out with the same physicians and in accordance with the Ferriman-Gallwey (FG) score. Results Benefits of the cream containing S. adstringens bark extract was observed in 60.98% (P < 0.001) of the subjects. FG score changed from 4 to 3 in the placebo group compared to 4-2 in the active. The cream suppressed the terminal hair growth and diminished the number of terminal hair. Subjects also described the reduction of skin hyperpigmentation, folliculitis and acne. Adverse events were not verified by physicians or patients. Conclusions The cream with 6.0% of the S. adstringens bark extract was effective on the reduction and on the reversion of the terminal hair excess, being considered a new promissory product for such finality.
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Inulin was used as a prebiotic to improve quality of skim milk fermented by pure cultures of Lactobacillus acidophilus Lactobacillus rhamnosus Lactobacillus bulgaricus and Bifidobacterium lactis binary co-cultures with Streptococcus thermophilus or a cocktail containing all them Inulin supplementation to pure cultures lowered the generation time with particular concern to S thermophilus and L acidophilus The generation time of all micro-organisms decreased in the following order mono-cultures co-cultures cocktail It was demonstrated a synergism between S thermophilus and the other strains and a bifidogenic effect of inulin Enumerations of L rhamnosus in cocktail markedly decreased compared to co-cultures likely because of greater competition for the same substrates The results of this work highlight the industrial potential of the cocktail mainly in terms of fermentation acceleration (C) 2010 Elsevier Ltd All rights reserved
Resumo:
Lactulose can be considered as a prebiotic, which is able to stimulate healthy intestinal microflora. In the present work, the use of this ingredient in fermented milk improved quality of skim milk fermented by Lactobacillus acidophilus, Lactobacillus rhamnosus, Lactobacillus bulgaricus and Bifidobacterium lactis in co-culture with Streptococcus thermophilus. Compared to control fermentations without lactulose, the addition of such a prebiotic in skim milk increased the counts of all probiotics, with particular concern to B. lactis (bifidogenic effect), the acidification rate and the lactic acid acidity, and concurrently reduced the time to complete fermentation (t(pH4.5)) and the pH at the end of cold storage for 1 to 35 days. (c) 2010 Elsevier B.V. All rights reserved.
Resumo:
Inulin was used as a prebiotic to improve the quality and consistency of skim milk fermented by co-cultures and pure Cultures of Lactobacillus acidophilus, Lactobacillus rhamnosus, Lactobacillus bulgaricus and Bifidobacterium lactis with Streptococcus thermophilus. We compared, either in the presence or absence of 4 g inulin/100 g, the results of the main kinetic parameters, specifically the generation time (t(g)), the maximum acidification rate (V(max)). and the times to reach V(max) (t(max)), to attain pH 5.0 (t(pH5.0)) and to complete the fermentation (t(pH4.5)). Post-acidification, lactic acid formation and cell counts were also determined and compared, either 1 day after the fermentation was complete or after 7 day storage at 4 degrees C. In general, inulin addition to the milk increased in co-cultures V(max), decreased t(max), t(g) and t(pH4.5), favored post-acidification, exerted a bifidogenic effect, and preserved almost intact cell viability during storage. In addition, S. thermophilus was shown to stimulate the metabolism of the other lactic bacteria. Contrary to co-cultures, most of the effects in pure Cultures were not statistically significant. The most important aspect of this paper is the use of the generation time as a toot to investigate the microbial response to inulin addition. (c) 2009 Elsevier Ltd. All rights reserved.
Resumo:
Inulin was used as a prebiotic to improve the quality and consistency of skim milk fermented by Lactobacillus acidophilus (La), Lactobacillus rhamnosus (Lr), Lactobacillus bulgaricus (Lb) and Bifidobacterium lactis (BI) with Streptococcus thermophilus (St), either in binary co-cultures or in cocktail containing all microorganisms. We compared, either in the presence of 40 mg inulin g(-1) or not, the results of the maximum acidification rate (V(max)) and the times to reach it (t(max)), to reach pH 5.0 (t(PH5.0)) and to complete the fermentation (t(f)). Post-acidification, lactic acid formation and cell counts were also compared after either 1 day (D1) or 7 days of storage at 4 degrees C (N). In co-culture, inulin addition to the milk increased V(max), decreased t(max) and t(f), favored post-acidification and exerted a bifidogenic effect. S. thermophilus proved to stimulate the metabolism of the other lactic bacteria and enhanced the product features. After D7, a significant prebiotic effect of inulin was observed in all co-cultures. Either after D1 or D7, the enumerations of Lr and BI in mixed culture markedly decreased compared to their respective co-cultures because of greater competition for the same substrates. (C) 2008 Elsevier Ltd. All rights reserved.
Resumo:
The postharvest development of crown rot of bananas depends notably on the fruit susceptibility to this disease at harvest. It has been shown that fruit susceptibility to crown rot is variable and it was suggested that this depends on environmental preharvest factors. However, little is known about the preharvest factors influencing this susceptibility. The aim of this work was to evaluate the extent to which fruit filling characteristics during growth and the fruit development stage influence the banana susceptibility to crown rot. This involved evaluating the influence of (a) the fruit position at different levels of the banana bunch (hands) and (b) changing the source-sink ratio (So-Si ratio), on the fruit susceptibility to crown rot. The fruit susceptibility was determined by measuring the internal necrotic surface (INS) after artificial inoculation of Colletotrichum musae. A linear correlation (r = -0.95) was found between the hand position on the bunch and the INS. The So-Si ratio was found to influence the pomological characteristics of the fruits and their susceptibility to crown rot. Fruits of bunches from which six hands were removed (two hands remaining on the bunch) proved to be significantly less susceptible to crown rot (INS = 138.3 mm 2) than those from bunches with eight hands (INS = 237.9 mm 2). The banana susceptibility to crown rot is thus likely to be influenced by the fruit development stage and filling characteristics. The present results highlight the importance of standardising hand sampling on a bunch when testing fruit susceptibility to crown rot. They also show that hand removal in the field has advantages in the context of integrated pest management, making it possible to reduce fruit susceptibility to crown rot while increasing fruit size.
Resumo:
Feijo, T.S., Cardozo, SX, Daleprane, J.B., Sabaa Srur, A.U.O. & Boaventura, G.T. [Evaluation of the influence of the proteinic quality of the genetically modified and organic soy beans in the growth of two generations of rats Wistar.] Avaliacao da influencia da qualidade proteica da soja geneticamente modificada e organica no crescimento de duas geracoes de ratos Wistar. Revista Brasileira de Medicina Veterinaria, 31(3):139-144, 2009. Programa de Pos-Graduacao em Patologia, Hospital Universitario Antonio Pedro. Centro de Ciencias Medicas, Universidade Federal Fluminense. Rua Marques do Parana, 303, Niteroi, RJ 24030-210, Brasil. E-mail: sergian@ufnj.br Sixty four Wistar rats, male of two consecutive generations determined as F(0) and F(1) were used to study the cumulative effect of two variety soy beans, cultivated with organic seasoning and genetically modified, The animals of each generation were divided into three groups of eight rats each fed on diets consisted of organic soy, soy genetically modified and casein respectively. All the animals received water and the diet ad libitum for period of 28 days. Where the diet consumption and the animals weight were evaluated. After statistic analysis of the results no expressive differences were observed on diet consumption, weight variation, protein efficient ratio and food efficiency ratio on same group of animals in the different generations. On the other hand, significant difference was found on final proteinic retention on animal descendants of the same groups; however of different generations. With this, the supplementation of organic soy with L-cistin provided better avail of this protein in relation to the protein of the soy genetically modified. However, this supplementation did not reveal efficiency in keeping the proteinic employment from one generation to another one, since soy varieties presented better performance on F(0) generation when compared with F(1).
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Sigatoka disease (SD) of bananas is caused by the pathogenic fungus Mycosphaerella musicola Leach. This disease provokes necrotic lesions on leaves and serious infestations can lead to a substantial reduction in the leaf area of infected plants and thus to yield losses. In addition to these effects on yield, SO was found to have an impact on fruit quality, especially because exported bananas ripen prematurely. In the present work, a plantation survey and experiments have been conducted in Guadeloupe (FWI) to assess the effect of this disease on the greenlife of bananas harvested at a constant physiological age, as measured in degree-days (dd). Our results revealed that bananas harvested at 900 dd from plants with high Sigatoka disease severity had normal diameter growth, but a shorter greenlife (GL) than bananas harvested from uninfected plants. These results indicate that SD is directly responsible for the reduction of banana greenlife since the reduction of GL could not be attributed to the harvest of fruits at a more advanced physiological age (dd). Furthermore, a correlation was noted between SO severity and GL The potential physiological mechanisms involved are also discussed. (C) 2008 Elsevier Ltd. All rights reserved.
Resumo:
Leaf fractions of Wilbrandia ebracteata were investigated for anti-ulcerogenic effects in ethanol and indomethacin-induced gastric ulcer assays in mice. Protective anti-ulcer effects were detected only in the ethanol-induced ulcer assay effects after pre-treatment with MeOH extract, MeOH chlorophyll-free, chlorophyll residue, HEX, DCM, aqueous MeOH fraction, ethyl acetate (EtOAc) and aqueous fractions. A potent anti-ulcerogenic effect was determined after pre-treatment of animals with EtOAc fraction, which was fractionated for isolation of active constituents. Seven flavonoids, 3`,4`,5,6,7,8-hexahydroxyflavonol, orientin, isoorientin, vitexin, isovitexin, luteolin, 6-methoxi-luteolin were isolated from the leaves of W. ebracteata (Cucurbitaceae) by chromatographic methods and identified by their spectral data. The data suggest that flavonoids are active anti-ulcerogenic compounds from leaves of W. ebracteata. The ability of scavenging free radicals was evaluated by DPPH reduction assay by TLC of flavonoids isolated.