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Rates of Nitrogen Mineralization of Meat and Bone Meals in Mediterranean Soils
No full textAnimal by-products such as meat and bone meals are now certified as free from bovine spongiform encephalopathy (BSE), and their use as organic fertilizers is considered safe again. Given that knowing the rates at which their nutrients are released is key to efficient use, nitrogen (N) mineralization in Mediterranean soils fertilized with meat and bone meals (MBMs) has been studied by means of 12 incubation experiments using three soils of different textures and organic-matter contents and five MBMs of varied origin and characteristics. After the application of the organic products, the amounts of mineral N released after 2, 4, 8, 12, 16, 20, and 35 weeks of aerobic incubation at 25 degrees C were measured and the data were adjusted to first-order reaction kinetics. In all cases, the results were consistent with the assumption of N mineralization being a first-order reaction with k constants ranging from 0.177 week(-1) to 1.603 week(-1). Mineralization was fast, with most of the N release taking place during the first 5-10 weeks of the incubations. Despite the different origin and characteristics of the MBMs compared in the experiment, soil type was the most influential factor in the mineralization process. The N mineralization rates were greater in the loam soil, suggesting a relevant role of enzymes immobilized in inorganic colloids such as clay
Biotecnología Agrícola
Get PDFLa domesticación de plantas, primera manipulación genética de los organismos vivos y origen de la Agricultura, representa la mayor contribución de la biotecnología al desarrollo de la humanidad. Los retos a superar en las próximas décadas para el sector agrario están determinados por el aumento demográfico y la demanda de materias primas para alimentación humana y animal, por las preferencias en el consumo, por aspectos medioambientales y legales, y por la globalización de la economía. Las aplicaciones de la biotecnología agrícola van a jugar un papel incuestionable en el logro de estos retos. Nuestro país posee unos buenos grupos en investigación básica y aplicada, con amplios conocimientos de la agrobiotecnología. El traslado de las necesidades del sector empresarial a la investigación, coordinando los departamentos de I+D+I de las empresas y los grupos de investigación de las universidades y organismos públicos de investigación es una finalidad a conseguir en el futuro
Caqui
Get PDFEl caqui pertenece a la especie Diospyros kaki Thunb. Esta especie se originó en el este de Asia. Su cultivo tiene muchas referencias en la cultura china que se remontan a varios siglos antes de Cristo. Desde allí, se introdujo en Japón en el siglo VII d. C. y desde Japón, ya en el siglo XIV, se introdujo en Corea. No existen registros de su cultivo en Europa hasta el siglo XVII. Durante este siglo y el siguiente se expandió por todo el área mediterránea, ya que las condiciones agroclimáticas de los países mediterráneos son muy propicias para esta especie. A finales del siglo XIX y durante el siglo XX se introdujo en América. Las corrientes migratorias desde los países asiáticos a Norteamérica introdujeron el cultivo del caqui en EEUU (California) y en Sudamérica (Brasil)
Effect of CO2 deastringency treatment on flesh disorders induced by mechanical damage in persimmon. Biochemical and microstructural studies
No full textManifestation of flesh browning while commercialising 'Rojo Brillante' persimmon is one of the main causes of postharvest loss. It is known that mechanical damage is a decisive factor for browning development and that astringent fruit is less sensitive to this disorder than fruit submitted to a CO2 deastringency treatment under standard conditions (24 h, 95% CO2, 20 degrees C). However, there is no information available about the mechanism behind this alteration. In the present study, we evaluated the effect of treatment with high CO2 concentrations applied for 0-40 h on the incidence of mechanical impact-induced flesh disorders using biochemical, chromatographic and microstructural techniques. Our results show that the longer the CO2 exposure, the higher the incidence and the greater the severity browning. A deastringency treatment with CO2 results in O-2(-) accumulation in fruit, which is greater the longer treatment is. However, mechanical damage triggers the browning manifestation, resulting in the accumulation of both O-2(-) and H2O2. In this oxidative stress state, which must be greater as higher the level of O-2(-) previously accumulated in the deastringency treatment, insoluble tannins initially uncolour, undergo an oxidation process and turn red-brown, observed as flesh browning. Moreover, we identified a new disorder, "pinkish-bruising", which is manifested in astringent fruit. The mechanism of this alteration, also associated with mechanical damage, seems similar to that of browning, but the oxidation process would affect soluble tannins. (C) 2013 Elsevier Ltd. All rights reserved
Acta Horticulturae
No full textNew hydroxypropyl methylcellulose (HPMC)-lipid edible composite coatings containing food additives or GRAS (‘generally regarded as safe’) compounds with antifungal properties were developed for postharvest preservation of fresh citrus fruit. Stable emulsions were selected among a large number of formulations prepared with different solid concentrations (6-12% wet basis, wb), total lipid (beeswax and shellac) contents (up to 60% dry basis), and concentrations of the antifungal ingredients (0.05-4.5% wb). Disk diameter tests were used for in vitro selection of the most effective stand-alone films against the pathogens, Penicillium digitatum and Penicillium italicum. Selected coatings were tested in vivo against green and blue molds on ‘Valencia’ oranges and ‘Ortanique’ and ‘Clemenules’ mandarins, incubated at 20°C for 7 days or stored at 5°C for up to 60 days. Coatings containing sodium benzoate or potassium sorbate, alone or mixed with sodium propionate, were the most effective in reducing the incidence and severity of both molds on fruit coated 24 h after fungal inoculation (curative activity). The antifungal activity of the coatings was fungistatic rather than fungicidal and was dependent on varietal susceptibility to Penicillium decay (higher activity on oranges than on mandarins, and on ‘Ortanique’ than on ‘Clemenules’). In general, green mold was more effectively controlled than blue mold on cold-stored fruit. Selected coatings significantly reduced fruit weight loss and maintained firmness during cold storage. Although the coatings modified the internal gas composition, they did not affect the overall sensory quality of oranges and mandarins
Desarrollo de un protocolo de embriogénesis somática para el saneamiento de las variedades de vid infectadas con GLRaV-3 y GFkV
Get PDFLa embriogénesis somática es una técnica de cultivo in vitro que permite el saneamiento de cultivares de vid (Vitis vinifera L.). Se ha analizado la presencia de los virus ArMvV, GELY, GFkV, GLRaV-1 y GLRaV-3 mediante real-time multiplex RT-PCR en hojas de plantas adultas de los cultivares “Valencí Blanc” y “Botó de Gall”. Además, se ha establecido un protocolo de embriogénesis somática para ambas variedades. La adición de 2 mgL-1 de 2,4D en el medio de cultivo incrementa el porcentaje de embriones cultivados así como el número de embriones por callos
Combined use of fluorescence and phase contrast microscopy for the determination of sperm viability
No full textThe aim of this study was to evaluate the combined use of fluorescenceand phase contrast microscopy as a new technique for the assessmentof sperm viability. For this, five pools of semen from three fertile boarswere frozen and thawed according to a standard protocol. Afterthawing, sperm samples were stained with 5 ll of propidium iodide(PI, 0.5 mg/ml) and incubated at 37°C in darkness 10 min. Subse-quently, samples were analyzed using a phase contrast microscopy(Nikon Eclipse E400, Tokyo, Japan) coupled with fluorescenceequipment (Nikon C-SHG1) with a mercury lamp (100 W) and aNikon G-2A filter with excitation/barrier filter of 510/590 which allowsa simultaneous excitation of blue and green. After displaying thesample under phase contrast microscopy the fluorescence wasconnected, non-viable sperm showed red color, and viable sperm werenot stained and visible. To determine the validity of this technique thesamples were also analyzed with a dual fluorescent staining (SYBR-14/PI) under fluorescence microscopy (Garner and Johnson, 1995; BiolReprod. 53, 276–284). The results did not show (57.6 vs. 57.2 1.5%live sperm; Garner and Johnson’s and described technique respec-tively) difference between techniques (p > 0.05). In conclusion, thecombined use of fluorescence and phase contrast microcopy using a PIstaining may be used for the determination of sperm viability, saving inthe use of fluorochromes and viable sperm are visible which wouldsimultaneously allow the acrosome state assessment
Validation of a methodology for rearing Spalangia cameroni (Hymenoptera: Pteromalidae) on Ceratitis capitata (Diptera: Tephritidae)
No full textSpalangia cameroni Perkins (Hymenoptera: Pteromalidae) is a pupal parasitoid of the Medfly, Ceratitis capitata (Wiedmann) (Diptera: Tephritidae), one of the principal pests of Spanish agriculture. Spalangia cameroni is a potential biocontrol agent for this pest if methods can be developed to mass-rear it effectively on C. capitata. Here, we report on the use of freeze-killed pupae of C. capitata to maintain a laboratory colony of S. cameroni, with a view to setting up a mass-rearing protocol. Realised fecundity, adult progeny, sex ratio, and superparasitism level were the principal parameters analysed. No significant differences were found in respect of these parameters between living or freeze-killedMedfly pupae used as hosts, although sex ratios showed a bias towards females in the case of freeze-killed pupae. Freeze-killed pupae were concluded to present the best option for the laboratory-rearing of S. cameroni, on account of ease of rearing, and avoidance of the emergence of Medfly adults
Long-term response of 'Clementina de Nules' citrus trees to summer regulated deficit irrigation
No full textRegulated deficit irrigation (RDI) has been assessed in a wide number of fruit crops. However, few are the studies dealing with long-term RDI strategies. In this work, we assessed the response of ‘Clementina de Nules’ citrus trees to summer RDI treatments [RDI-1, irrigated at 50% of crop evapotranspiration (ETc) and RDI-2, irrigated at 35% ETc] during six consecutive seasons (2007–2012). Although water restrictions were applied according to reductions over ETc, threshold values of stem water potential (−1.3 to −1.5 MPa in the RDI-1 treatment and −1.5 to −1.7 MPa in the RDI-2) were also considered for scheduling deficit irrigation. Results showed that the water stress imposed in the RDI-2 treatment had a noticeable impact on fresh fruit weight, reducing yield and economic return over the six years and more so during the first two years in comparison to a control treatment irrigated at 100% ETc during the whole season. The RDI-1 strategy had a lower impact than the RDI-2 treatment on the fresh fruit weight and did not significantly reduce yield or the economic return over the six seasons. RDI improved fruit quality particularly in the most stressed treatment by increasing the total soluble solids and titratable acidity. RDI also reduced vegetative growth although the reduction was not proportional to the level of stress reached by trees. On average for the six years, the relative trunk growth and pruning weight in both RDI treatments were reduced around 20% in comparison with the control trees. Long-term deficit irrigation did not lead to a noticeable accumulation of salts in the root zone. Overall, these results show that the RDI-1 strategy here studied can be successfully applied during six consecutive seasons in commercial ‘Clementina de Nules’ orchards allowing water savings of 15% without any detrimental effect on tree performance
Laboratory and field assessment of the capacitance sensors Decagon 10HS and 5TE for estimating the water content of irrigated soils
No full textCapacitance sensors such as Decagon 10HS and 5TE are increasingly used for soil water content (theta) estimation. However, their reliability and limitations in clayey soils irrigated with saline waters have not been completely characterized under field conditions. Four levels of soil water content were combined with six levels of soil salinity in twenty-four pots to assess the performance of both sensors in a wide range of soil salinities. A simplified power-law dielectric mixing model was calibrated in the laboratory to estimate the theta of a clay loam soil from the measurements of apparent dielectric permittivity (epsilon(b)) performed with both sensors. The calibrated equation was subsequently validated for the estimation of theta at two depths in six irrigated salt-threatened soils with clayey textures in SE Spain. The 10HS sensor provides higher estimations of epsilon(b) than the 5TE. Besides, the 5TE sensor was more sensitive to soil salinity. Consequently, a different calibration was carried out for each sensor. When all the soil salinity treatments were included in the calibrations, the results were poor. However, for soil apparent electrical conductivities below 1.7 dS m(-1) the 5TE sensor could be calibrated with low prediction errors, and with the calibration parameters b(0) and b(1) very close to their characteristic values in clayey and mineral soils. In field testing, the 5TE sensors calibrated with the obtained equation provided average correct estimations with an error of +/- 0.05 m(3) m(-3). On the contrary, the 10HS sensor overestimated the soil water content by 0.07 m(3) m(-3) on average. The proposed simple calibration equation for the 5TE sensor can be reliably used under field conditions to estimate theta of irrigated clayey soils up to an apparent electrical conductivity of 1.7 dS m(-1). (C) 2013 Elsevier B.V. All rights reserved