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Respuesta del arroz ecológico a diferentes productos fertilizantes en el delta del Ebro
Get PDFEn una parcela de arrozal ecológico localizada en la Finca Piloto de Riet Vell en el
Delta del Ebro, se evaluó durante la campaña de 2009 la eficacia de dos abonos
orgánicos: gallinaza compostada y un producto comercial (Labinor), elaborado a partir de
subproductos cárnicos. Los tratamientos incluidos en el experimento fueron: T1, testigo
(sin fertilización), T2, T3 y T4, gallinaza a dosis de 120, 145 y 170 kg N/ha, y T5, T6 y T7,
Labinor a 95, 115 y 135 kg N/ha, respectivamente. Los resultados obtenidos pusieron de
manifiesto una respuesta significativa del cultivo a la fertilización orgánica, tanto en
desarrollo vegetativo como en la producción. Los rendimientos obtenidos con el abono
Labinor fueron superiores a los generados con la gallinaza con todas las dosis. Y el
rendimiento más alto se logró con la dosis baja de Labinor (95 kg N/ha). Asimismo la
eficiencia del nitrógeno, evaluada como porcentaje del nitrógeno recuperado por el cultivo,
registró con el producto Labinor unos valores entre 27 y 31%, mientras que con la
gallinaza se obtuvieron unas cifras más bajas (entre 14 y 21%). Algunos parámetros
nutricionales del cultivo (contenido de nitrógeno en el grano y de nitrógeno, fósforo y
magnesio en la paja) resultaron afectados de forma significativa con la fertilización
orgánica. Las cantidades de nutrientes absorbidas por las plantas de arroz (grano+paja)
mostraron amplias diferencias en función del abono y dosis aplicada. La mayor absorción
de nutrientes correspondió al tratamiento dosis alta (134 kg N/ha) de Labinor
Acta Horticulturae
No full textThe main objective of the production and distribution chain of fruit is to ensure that the product reaches the consumer in its optimal state of maturation. Prior to commercialization, the fruit stays in cool chambers for a short time. Nowadays, used methods by packinghouses are too expensive and they only provide samples of the atmosphere in some points of the chamber. Finally, these methods are too simple and unreliable. IVIA, through the research project "Sensogest", is developing an infrastructure capable of acquiring, pre-processing and transmitting information about the atmosphere of the cool rooms in a packinghouse to a remote station. This work reviews the infrastructure that IVIA is developing in order to acquire relevant information related to maturation of fruits (carbon dioxide and ethylene production rate) and storage conditions (temperature and relative humidity) in cool rooms. The first tests to design a new ethylene sensor, the performance of the developed CO2 detector and the ability of a communication system based on the AS-Interface to monitor signals from temperature and relative humidity sensors will be shown
Exopolysaccharides favor the survival of Erwinia amylovora under copper stress through different strategies
No full textErwinia amylovora causes fire blight, a destructive disease of rosaceous plants very difficult to control. We demonstrated that copper, employed to control plant diseases, induces the "viable-but-nonculturable" (VBNC) state in E. amylovora. Moreover, it was previously reported that copper increases production of its main exopolysaccharide (EPS), amylovoran. In this work, the copper-complexing ability of amylovoran and levan, other major EPS of E. amylovora, was demonstrated. Following this, EPS-deficient mutants were used to determine the role of these EPSs in survival of this bacterium in AB mineral medium with copper, compared to their wild type strain and AB without copper. Total, viable and culturable counts of all strains were monitored for six months. With copper, a larger fraction of the viable population of EPS mutants entered into the VBNC state, and earlier than their wild type strain, showing the contribution of both EPSs to long-term survival in a culturable state. Further, we demonstrated that both EPSs can be used as carbon source by E. amylovora under deprivation conditions. Overall, these previously unreported functions of amylovoran and levan provide survival advantages for E. amylovora, which could contribute to its enhanced persistence in nature. (C) 2010 Elsevier Masson SAS. All rights reserved
HS-SPME Comparative Analysis of Genotypic Diversity in the Volatile Fraction and Aroma-Contributing Compounds of Capsicum Fruits from the annuum-chinense-frutescens Complex
No full textVolatile constituents of ripe fruits of 16 Capsicum accessions from the annuum-chinense-frutescens complex, with different aroma impressions and geographical origins, were isolated by headspace-solid phase microextraction (HS-SPME) and analyzed by gas chromatography-olfactometry-mass spectrometry (GC-sniffing port-MS). More than 300 individual compounds could be detected in the studied genotypes; most of them could be identified by comparing mass spectra and retention times with authentic reference substances or literature data. Esters and terpenoids were the main groups, although other minor compounds, such as nitrogen and sulfur compounds, phenol derivatives, norcarotenoids, lipoxygenase derivatives, carbonyls, alcohols, and other hydrocarbons, were also identified. The sniffing test revealed that the diversity of aromas found among the studied cultivars is due to qualitative and quantitative differences of, at least, 23 odor-contributing volatiles (OCVs). C. chinense, and C. frutescens accessions, with fruity/exotic aromas, were characterized by a high contribution of several esters and ionones and a low or nil contribution of green/vegetable OCVs. Different combinations of fruity/exotic and green/vegetable OCVs would explain the range of aroma impressions found among C. annuum accessions. Implications of these findings for breeding and phylogeny studies in Capsicum are also discussed
Relationships between xylem anatomy, root hydraulic conductivity, leaf/root ratio and transpiration in citrus trees on different rootstocks
No full textThe aim of the study was to determine the extent in which leaf and whole plant transpiration (Tp) were influenced by root hydraulic conductance (K(r)), leaf to root ratio and leaf mass. Also, the relationships between the anatomic characteristics of roots and K(r) were investigated. To this end, 9-month-old seedlings of the citrus rootstocks Cleopatra mandarin (CM), Poncirus trifoliata (PT), and their hybrids Forner-Alcaide no 5 (FA-5) and Forner-Alcaide no 13 (FA-13) and 15-month-old trees of Valencia orange budded on these four rootstocks were tested. The hybrid FA-13 and PT had higher values of K(r) and leaf transpiration rates (E) than FA-5 and CM. There was a positive curvilinear correlation between E and K(r). Furthermore, E levels in the different types of plants decreased with increased leaf/root (L/R) ratios. Pruning of the roots and defoliation confirmed that transpiration rates were strongly influenced by the L/R ratio. However, variations in E because of differences in L/R ratios were less pronounced in trees budded on FA-13 and PT than on the other two rootstocks. In addition, there was a positive correlation between Tp and leaf biomass, although differences between rootstocks may be attributed to differences in K(r). The average lumen diameter of xylem vessels was greater in rootstocks with high K(r). Size of epidermal and hypodermal cells of fibrous roots may also restrict K(r)
Development of a simplified NASBA protocol for detecting viable cells of the citrus pathogen Xanthomonas citri subsp citri under different treatments
Get PDFNucleic acid sequence based amplification (NASBA) is a method of amplifying RNA, for the detection of RNA viruses and human pathogenic bacteria. Recently, NASBA has also been employed for the detection of plant diseases caused by viruses and quarantine bacteria. A major citrus pathogen, Xanthomonas citri subsp. citri (Xcc), causal agent of citrus bacterial canker, is being studied in depth due to its economic importance, with recent focus concentrating on its viability and survival under different stress conditions and control treatments. In this work, a NASBA protocol using primers for gumD mRNA has been developed to assess the viability of this pathogen under different bacteriocidal treatments. This method is rapid, specific and sensitive, and is able to detect viable bacterial cells, using a hybridization device which allows the visualization of the results in only 30 min. The usefulness of the method has been confirmed with bacterial suspensions subjected to different heat treatments and to sodium orthophenylphenate
Effect of Antifungal Hydroxypropyl Methylcellulose-Lipid Edible Composite Coatings on Penicillium Decay Development and Postharvest Quality of Cold-Stored "Ortanique" Mandarins
No full textEdible composite coatings based on hydroxypropyl methylcellulose (HPMC), hydrophobic components (beeswax and shellac), and food preservatives with antifungal properties were evaluated on "Ortanique" mandarins during long-term cold storage. Selected food preservatives included potassium sorbate (PS), sodium benzoate (SB), sodium propionate (SP), and their mixtures. Intact mandarins or mandarins artificially inoculated with the pathogens Penicillium digitatum and Penicillium italicum, the causal agents of citrus postharvest green (GM) and blue (BM) molds, respectively, were coated and stored up to 8 wk at 5 degrees C + 1 wk of shelf-life at 20 degrees C. HPMC-lipid coatings containing food preservatives controlled better GM than BM on Ortanique mandarins. SB- and SB + SP-based coatings reduced the incidence of GM by about 35% after 4 wk at 5 degrees C. Among all coatings, only the SB-based coating reduced the incidence of GM (about 16%) after 6 wk at 5 degrees C. All coatings significantly reduced disease severity of both GM and BM after 6 wk at 5 degrees C. Analytical and sensory fruit quality was evaluated on intact mandarins. All coatings, especially the SB + SP-based coatings, were effective to control weight loss and maintain the firmness of coated mandarins. Internal gas concentration, juice ethanol and acetaldehyde content, sensory flavor, off-flavor, and fruit appearance were not adversely affected by the application of the antifungal coatings. Further studies should focus on the modification of some physical characteristics of the coatings to improve the gloss and visual aspect of treated mandarins
Abonado de los cítricos
Get PDFLas especies de los cítricos con interés comercial pertenecen a la familia de las Rutáceas, subfamilia Aurantioideas. El sistema taxonómico subdivide a los cítricos cultivados en tres géneros: Poncirus, que posee una sola especie (P. Trifoliata), Fortunella, donde se incluyen especies de pequeños árboles y arbustos, y Citrus, que posee 16 especies de hoja perenne y son las más importantes desde el punto de vista agronómico (Ortiz, 1985)
A comparison of several traps and attractants as a first approach to the use of mass trapping against the olive fruit fly (Diptera, Tephritidae) in the Valencian Community
Get PDFThe Valencian Community (on the eastern coast of Spain) is the fourth
Spanish region in olive production (for oil and olives). One of the main problems for
this crop is the olive fruit fly, Bactrocera oleae (Gmelin) and this pest has
traditionally been combated in the region by the use of chemicals. Nowadays, it is
been studied the technical and economical feasibility in using some ecological
methods against the pest. One of these methods could be the mass trapping, so
some trials have been started to know its effectiveness, its cost and its effect on
natural enemies in order to select the best one