940 resultados para olive trees
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A simple and rapid method for the determination of 13 organophosphorus insecticides and their metabolites in olive oil by GC is described. The pesticide was extracted from oil with acetonitrile and no cleanup was needed. GC-nitrogen-phosphorus detection response factors of pesticides were affected by solvents and coextractive substances. Pesticides in hexane showed on average higher response factors. Standards were prepared in the residue-free oil extract solubilized in hexane to handle effects of matrix and solvent. The low amount of coextractive substances does not decrease the column efficiency, even after a few hundred analyses. Recovery at three fortification levels (ca. 0.1, 1.0 and 3.0 mg/kg) ranged from 74 to 118%, With coefficients of variation ranging from 1 to 16.
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In this work, a CE method for the determination of olive oil acidity was proposed. The method was based on an ethanolic extraction (at 60 degrees C) of the oil long-chain free fatty acids (LC-FFAs) components followed by CE determination in pH 6.86 phosphate buffer at 15 mmol/L concentration containing 4 mmol/L sodium dodecylbenzenesulfonate (SDBS), 10 mmol/L polyoxyethylene 23 lauryl ether (Brij 35((R))), 2% v/v 1-octanol and 45% v/v ACN under indirect UV detection at 224 nm. Although this electrolyte promoted baseline separation of myristic acid (C14:0) (internal standard (IS)) and olive oil major components (palmitic acid (C16:0), oleic acid (C18:1c) and linoleic acid (C18:2cc)) in less than 8 min, after a few injections, the electropherogram profiles were severely altered (peak broadening, migration time shifts, etc.) and the current increased substantially. An adsorption study was conducted revealing that the dissolution of the capillary external polyimide coating during the electrophoretic run caused the detrimental effect. After removal of the capillary tip coating, ten consecutive injections could be performed without any disturbances and this simple procedure was, therefore, implemented during quantitative purposes. The reliability of the proposed method was further investigated by the determination of acidity of an extra virgin olive oil sample in comparison to the established methodology (AOCS method Ca 5a40, alkaline volumetric titration (AVT)). No statistical differences were found within 95% confidence level. A % acidity of 0.39 +/- 0.02 was found for the olive oil sample under consideration.
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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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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The work described was part of the programme, Innovative biological indicators to improve the efficiency of water and nitrogen use and the fruit quality in tree crops Project, a partnership between ISA and INRA. Field studies were conducted in Portugal on different irrigated plots of nectarine trees; a fully irrigated (unstressed plot) and a plot that was not irrigated for some days (stressed plot). The aim of this work was to investigate the effects of plant water stress on canopy temperature, to determine the nonwater-stressed baseline and to observe diurnal and seasonal variations of Crop Water Stress Index (CWSI). Canopy temperature, psychrometric and wind speed data were taken each half-hour, between 9:30 and 15:30 h. Results showed that canopy temperature was higher during the daytime, for both unstressed and stressed plots. A linear regression of canopy-air temperature differential and the vapor pressure deficit (non-water-stress baseline) showed a r2= 0.65. During the stress period, the average canopy temperature of the stressed plot was up to 5.4°C higher than the unstressed plot. Diurnal and seasonal average of CWSI values showed differences between unstressed and stressed plots, during the stress period.
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This paper describes the phenology of leaf, flower, and fruit phenology in the Atlantic rain forests of southeastern Brazil. For 17 months, we observed the phenological patterns of trees from two Atlantic forest types at four sites: premontane forest (Sites I and IV; the typical Atlantic rain forest) and coastal plain forest (Sites II and III). All sites experience a nonseasonal, tropical wet climate, characterized by an annual rainfall usually > 2000 mm and lacking a dry season. We tested for the occurrence (or absence) of seasonal phenological patterns within each site and compared the patterns detected among the four different forest sites using circular statistics. The expected weakly seasonal phenological patterns were not observed for these forests. Flowering and leaf flush patterns of Atlantic rain forest trees were significantly seasonal, concentrated at the beginning of the wettest season, and were significantly correlated with day length and temperature. These results stress the influence that seasonal variation in day length has on ever-wet forest tree phenology. Fruiting phenologies were aseasonal in all four forests. Flowering patterns did not differ significantly among three of the four forest sites analyzed, suggesting the occurrence of a general flowering pattern for Atlantic rain forest trees.
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Currently there is very little information on the response of fruiting perennial plants to applied P. This is especially true for tropical production areas where soils have a high capacity of P fixation, and are poor in native phosphorus. An alternative to soil P fertilization, which is inefficient in fixing soils, is to apply phosphorus as a foliar spray. P is quickly absorbed by leaves, and is redistributed quite well through the plants because its phloem mobility, and foliar application may be a viable practice. The purpose of this present work, is to determine the effectiveness of foliar P application on the nutritional status and yield of guava. The experiment was done in a Typic Hapludox, for three consecutive agricultural years, in an adult orchard of 'Paluma' guava. Five treatments were tested: four rates leaf applications of P (0-0.5-1.0 and 2.0% of P2O5) and a control where P was applied to soil (200 g of P2O5/plant). Through the results it was verified that the foliar application of P altered the concentration of the nutrient in the soil (13 to 48 mg dm-3 P-resin), and in the guava leaves (1.2 to 1.8 g of P kg-1), but did not affect the production of fruits. In conclusion, in field conditions, it is viable to combine the phosphorus foliar fertilization with disease control, without increasing the operations and, consequently, the production cost.
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Caloric intake is higher than recommended in many populations. Therefore, enhancing olive oil intake alone may not be the most effective way to prevent cardiovascular diseases. The purpose of the present study was to analyse the association of olive oil and dietary restriction on lipid profile and myocardial antioxidant defences. Male Wistar rats (180-200 g, n = 6) were divided into 4 groups: control ad libitum diet (C), 50% restricted diet (DR), fed ad libitum and supplemented with olive oil (3 mL/(kg-day)) (OO), and 50% restricted diet and supplemented with olive oil (DROO). After 30 days of treatments, OO, DR, and DROO groups had increased total cholesterol and high-density lipoprotein cholesterol concentrations. DR and DROO animals showed decreased low-density lipoprotein cholesterol. DROO had the lowest low-density lipoprotein cholesterol concentration. Total lipids and triacylglycerols were raised by dietary restriction and diminished by olive oil. OO rats had higher myocardial Superoxide dismutase and lower catalase and glutathione peroxidase activities than C rats. DR and DROO showed enhanced cardiac Superoxide dismutase, catalase, and glutathione peroxidase activities from the control. Olive oil supplementation alone improved the lipid profile but was more effective when coupled with dietary restriction. There was a synergistic beneficial action of dietary restriction and olive oil on serum lipids and myocardial antioxidant defences.
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Analysis of variance and covariance was preformed on growth traits (stem girth, bark thickness, total height gain and rubber yield) of 22 open-pollinated progenies of the rubber tree Hevea brasiliensis from an Asian Hevea collection introduced to Agronomic Institute (Instituto Agronômico, Campinas, São Paulo, Brazil; IAC) in 1952. This progeny trial was replicated at three sites in São Paulo state and it was found that at three years from sowing there was statistically significant variation for girth, bark thickness, height and rubber yield. An individual test sites, values of individual plant heritability for girth ranged from ĥ i 2 = 0.36 to ĥ i 2 = 0.89 whereas values for heritability for progeny means ranged from ĥ i 2 = 0.77 to ĥ i 2 = 0.87. These moderate and high heritabilities suggest that a combination of progeny and within-progeny selection would be effective at increasing girth in this population at individual sites. Across sites, values of individual-plant heritability for girth ranged from ĥ i 2 = 0.36 to ĥ i 2 = 0.47, whereas values for heritability of progeny means girth ranged from ĥ x̄ 2 = 0.77 to ĥ x̄ 2 = 0.87. There were high positive genetic correlations between increased girth and bark thickness suggesting that breeding aimed at increasing girth would also increase bark thickness and possibly height. Copyright by the Brazilian Society of Genetics.