Effect of dips in a 1-methylcyclopropene-generating solution on 'Harrow Sun' plums stored under different temperature regimes     

Manganaris GA  Vicente AR  Crisosto CH  Labavitch JM 《Journal of agricultural and food chemistry》2007,55(17):7015-7020

The effect of postharvest dips in a 1-methylcyclopropene-generating solution of the formulation AFxRD-038 (Rohm & Haas) on plum fruit (Prunus salicina Lindell cv. 'Harrow Sun') quality and ripening during storage was determined. Fruit weight loss, tissue firmness, soluble solids content (SSC), titratable acidity (TA), ethylene production, respiration, and the activities of the cell wall modifying enzymes polygalacturonase (PG), 1,4-beta-D-glucanase/glucosidase (EGase), beta-galactosidase (beta-gal), and pectin methylesterase (PME) were measured. Fruit reddening, anthocyanin content, and phenylalanine ammonia-lyase (PAL) activity were also analyzed. The 1-MCP-treated fruit showed reduced ethylene production and respiration rate and delayed softening, which was associated with the reduction in the activity of PG, EGase, and beta-gal. The immersion in 1-MCP-generating solutions also decreased weight and acidity loss without modifying the fruit SSC. The immersion treatment was particularly effective in the fruit stored at 5 degrees C, keeping higher overall quality, maintaining lower levels of anthocyanins and PAL activity, and preventing flesh reddening. The present data show that beneficial effects in delaying plum fruit ripening and controlling chilling injury can be obtained by dipping the fruits in a solution of this novel 1-MCP-generating formulation.  相似文献   

A Modeling Study of the Impact of a Power Plant on Ground-Level Ozone in Relation to its Location: Southwestern Spain as a Case Study     

Nuria Castell  Enrique Mantilla  Ariel F. Stein  Rosa Salvador  Millán Millán 《Water, air, and soil pollution》2010,209(1-4):61-79

The impact of atmospheric industrial emissions on secondary pollutant formation depends on many factors; one of the most important being the environmental setting in which the industry is located. The environmental setting affects an industry’s impact on ozone levels through both the air mass dispersion (a function of topography and wind patterns) and the emissions of organic volatile compounds (VOC) and nitrogen oxides (NO _x ) in the area. This model-based study shows how the sensitivity of surface ozone changes with the choice of source location. For the analysis, seven points distributed along the Tinto–Guadalquivir Basin (in the Southwestern Iberian Peninsula) were selected. This area is characterized by the close proximity of natural environments and crop fields to cities, roads, and industrial areas with high NO _x emissions. Natural VOC emissions represent more than 60% of the total non-methane volatile organic compounds emitted in the study area. The results reveal that the largest increases in ozone levels are produced when the industry is located both far away from NO _x emission sources and near to biogenic VOC emissions. Furthermore, the highest increases over the hourly and 8-hourly maximums, as well as the highest accumulated daily values, are found in areas characterized by high VOC/NO _x emission ratios and NO _x sensitivity. The study of the recurrent meteorological patterns along with the distribution of chemical indicators of the O₃–NO _x –VOC sensitivity allows the determination of the industry’s geographical impact on ozone levels. This information enables air quality managers to decide the future location of an industry minimizing its impact on smog levels.  相似文献   

Geographical distribution of the DL1 and DL2 genes causing hybrid dwarfism in Phaseolus vulgaris L., their association with seed size,and their significance to breeding   总被引：1，自引：0，他引：1  

Shree P. Singh  J. Ariel Gutiérrez 《Euphytica》1984,33(2):337-345

Summary Dwarlism in F₁ hybrids has been observed in over 100 crosses of dry beans (Phaseolus vulgaris L.) at the Centro Internacional de Agricultura Tropical (CIAT), Cali, Colombia. In each cross, one parent always had small seeds and the other parent either medium or la ge ones. This apparent incompatibility between the two groups of germplasm was controlled by two complementary, dominant genes: DL₁ and DL₂. Smallseeded bean lines carried gene DL₁ and originated in Brazil, Colombia, Guatemala, and Mexico; medium for large-seeded bean lines carried gene DL₂ and were from Bolivia, Brazil, Chile, Colombia, Turkey, The United States, and West Germany. Thes two genes have probably played an important role in the evolution of dry bean forms of different seed sizes by serving as a genetic barrier or isolating mechanism, thus limiting free genetic recombination between the two germplasm groups.Apparent differences in the adaptiveness and yielding ability of the two groups of bean germplasm, smallys, medium- and large-seeded, and some breeding implications for manipulation of the genes causing F₁ hybrid dwarfism were also discovered.  相似文献   

Effect of plant density on selection for seed yield in two population types of Phaseolus vulgaris L.     

Shree P. Singh  J. Ariel Gutiérrez 《Euphytica》1990,51(2):173-178

Summary Pedigree selection for seed yield, using early generation yield tests, was practiced from the F₂ to F₇ in two populations of common bean (Phaseolus vulgaris L.) in three plant densities: 66, 133, and 266 thousand plants ha^-1 at CIAT-Palmira, Colombia. The six highest yielding lines selected from each plant-density, along with 13 parents, were evaluated in a 7×7 lattice design with three replications at the three densities utilized for selection, and at 399,000 plants ha^-1 in 1988 and 1989.Based on the mean performance of selected lines and the mean of the parents, selection for seed yield was effective in all densities in both populations. However, none of the lines selected from the population within the race Mesoamerica (TC 4673) significantly outyielded their best parent under any plant density. The highest yielding lines selected from the interracial population (TR 4635) outyielded their best parent irrespective of the plant-density used for selection. The highest yielding line originated from the highest density used for selection. Low density was neither good for selection nor for evaluation and identification of high-yielding cultivars of common bean. There was no significant difference between the mean yield of lines selected at the intermediate and high population densities. The effects of plant density, year, and their interactions were significant for seed yield.  相似文献   

The search for carbon sinks in the tropics     

Ariel E. Lugo 《Water, air, and soil pollution》1992,64(1-2):3-9

The study and modeling of the global C cycle have been dominated by the assumption that the atmosphere and the biota were in C steady state prior to the industrial revolution. This view led to the perception that most of the terrestrial biota was neutral with regards to the C concentration of the atmosphere. Recent evidence suggests that neither the atmosphere nor the biota were in C steady state prior to, or since, the industrial revolution. Therefore, it is now necessary to re-visit the role of natural processes in the global C cycle, study the C cycle in its totality, and focus attention on the magnitude of potential C sinks in ecosystems previously thought to be neutral with respect to atmospheric C. “An improved understanding of the CO₂ cycle is essential to predict the future rate of any atmospheric CO₂ increase and to plan eventually for an international CO₂ management strategy” Tans et al. (1990).  相似文献   

Acknowledgments     

Dr. Joe Wisniewski  Dr. Ariel E. Lugo 《Water, air, and soil pollution》1992,64(1-2):xi-xi

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Generation of spatially coherent light at extreme ultraviolet wavelengths     

Bartels RA  Paul A  Green H  Kapteyn HC  Murnane MM  Backus S  Christov IP  Liu Y  Attwood D  Jacobsen C 《Science (New York, N.Y.)》2002,297(5580):376-378

We present spatial coherence measurements of extreme ultraviolet (EUV) light generated through the process of high-harmonic up-conversion of a femtosecond laser. With a phase-matched hollow-fiber geometry, the generated beam was found to exhibit essentially full spatial coherence. The coherence of this laser-like EUV source was shown by recording Gabor holograms of small objects. This work demonstrates the capability to perform EUV holography with a tabletop experimental setup. Such an EUV source, with low divergence and high spatial coherence, can be used for experiments involving high-precision metrology, inspection of optical components for EUV lithography, and microscopy and holography with nanometer resolution. Furthermore, the short time duration of the EUV radiation (a few femtoseconds) will enable EUV microscopy and holography to be performed with ultrahigh time resolution.  相似文献   

A selective activity-dependent requirement for dynamin 1 in synaptic vesicle endocytosis     

Ferguson SM  Brasnjo G  Hayashi M  Wölfel M  Collesi C  Giovedi S  Raimondi A  Gong LW  Ariel P  Paradise S  O'toole E  Flavell R  Cremona O  Miesenböck G  Ryan TA  De Camilli P 《Science (New York, N.Y.)》2007,316(5824):570-574

Dynamin 1 is a neuron-specific guanosine triphosphatase thought to be critically required for the fission reaction of synaptic vesicle endocytosis. Unexpectedly, mice lacking dynamin 1 were able to form functional synapses, even though their postnatal viability was limited. However, during spontaneous network activity, branched, tubular plasma membrane invaginations accumulated, capped by clathrin-coated pits, in synapses of dynamin 1-knockout mice. Synaptic vesicle endocytosis was severely impaired during strong exogenous stimulation but resumed efficiently when the stimulus was terminated. Thus, dynamin 1-independent mechanisms can support limited synaptic vesicle endocytosis, but dynamin 1 is needed during high levels of neuronal activity.  相似文献   

Susceptibility of the Mexican bean beetle <Emphasis Type="Italic">Epilachna varivestis</Emphasis> Mulsant (Coleoptera: Coccinellidae) to endemic isolates of <Emphasis Type="Italic">Beauveria bassiana</Emphasis> (Balsamo) Vuillemin (Hypocreales: Clavicipitaceae)     

Jaime A. Ocampo-Hernández  Patricia Tamez-Guerra  Samuel Pineda  Fernando Tamayo-Mejía  Ariel Guzmán-Franco  José I. Figueroa de la Rosa  Ana Mabel Martínez 《Journal of pest science》2011,84(4):471-477

Entomopathogenic fungi represent excellent candidates for biological insecticides. Among the many entomopathogenic fungi, Beauveria bassiana (Balsamo) Vuillemin (Hypocreales: Clavicipitaceae) is one of the most promising species. Here, we report the results of infection studies performed using four B. bassiana native isolates (Bb37, Bb38, Bb40, and Bb45) compared with the commercial product Mycotrol^® (strain GHA) on adult Mexican bean beetle Epilachna varivestis Mulsant (Coleoptera: Coccinellidae), one of the most important pests of bean production in Mexico. First, single concentration (1 × 10⁸ conidia mL^?1) assays were carried out using all isolates applied using an immersion method. Examinations at 10 days after inoculation indicated that isolates Bb37, Bb38, and Bb40 significantly reduced adult survival, causing 60–75% mortality compared to the commercial strain GHA (33%) and control (29%). Second, using two selected isolates (Bb37 and Bb40), the mean lethal concentration values (LC₅₀) were estimated for third instar larvae and adult E. varivestis. The LC₅₀ values for Bb37 and Bb40 isolates decreased 5.26-fold and 3.19-fold, respectively, in third instars compared with adults. However, such difference for Bb40 isolate was not significant. Finally, an experiment, to compare the median survival time (MST) values between third instar and adult E. varivestis, was conducted using Bb37 and Bb40 at 1 × 10⁹ conidia mL^?1. MST values were significantly reduced against larvae (87 and 100 h) compared with adults (130 and 134 h) by Bb37 and Bb40, respectively. We conclude that native isolates of B. bassiana represent an important alternative for the control of E. varivestis. However, to demonstrate its effectiveness under field conditions, detailed studies are needed.  相似文献   

Molecular characterization and phylogenetic analysis of Newcastle disease virus isolates from healthy wild birds     

Zanetti F  Berinstein A  Pereda A  Taboga O  Carrillo E 《Avian diseases》2005,49(4):546-550

Wild waterfowl is considered a natural reservoir of potentially infectious agents and a source of pathogenic viruses like avian paramyxoviruses type 1 (APMV 1). In 1997, commercial poultry in Argentina had reached the status of being free from virulent Newcastle disease virus (NDV) infections. Vaccination and biosecurity measures are actively performed to maintain this preferential sanitary condition. However, the risk of reintroduction of pathogenic viruses is always present. In this context, we conducted a study to describe the status of wild healthy birds in a geographic region relevant for the poultry industry. The presence of anti-NDV antibodies was determined in different species in all areas sampled suggesting previous contact with NDV. Seven ND viruses were isolated and characterized as apathogenic strains by biological and molecular methods. The phylogenetic analysis revealed that the majority of the Argentinian isolates form a subgroup related to viruses of genotype II. The results presented here highlight the importance of maintaining strict biosecurity measures and vaccination programs in poultry industries in order to preserve the virulent NDV-free status for commercial flocks in the country.  相似文献