Polycyclic Aromatic Hydrocarbons in Soils from European High Mountain Areas   总被引：1，自引：0，他引：1  

Roberto Quiroz  Joan O. Grimalt  Pilar Fernandez  Lluis Camarero  Jordi Catalan  Evzen Stuchlik  Hansjoerg Thies  Ulrike Nickus 《Water, air, and soil pollution》2011,215(1-4):655-666

Polycyclic aromatic hydrocarbons (PAHs) were analyzed in 70 soils distributed in mountain areas such as Montseny (300?C1,700 m), Pyrenees (1,500?C2,900 m), Alps (1,100?C2,500 m), and Tatras (1,400?C1,960 m). Average total PAH concentrations, excluding retene and perylene, were about 400 ng/g in the Pyrenees and 1,300?C1,600 ng/g in the other mountain ranges. No correlations between PAH concentrations and total organic carbon were observed. Retene was the major PAH in the Pyrenean soils of lower altitude. No altitudinal dependence was found between soil PAH concentrations and elevation for the whole dataset. However, in the Tatra soils a statistically significant correlation with altitude was observed involving higher concentrations at higher altitude. This correlation was due to the statistically significant altitudinal dependence of the more volatile PAHs. Another observed altitudinal trend concerned the benz[a]anthracene/(benz[a]anthracene + chrysene + triphenylene) and the benzo[a]pyrene/(benzo[a]pyrene + benzo[e]pyrene) ratios that exhibited a decrease in the more chemically labile compounds, benz[a]anthracene and benzo[a]pyrene, respectively, in the soils located at higher altitude. This observation is consistent with the expected higher photooxidation at higher mountain altitude.  相似文献   

Effects of Vegetation Removal and Urea Application on Iron and Nitrogen Redox Chemistry in Riparian Forested Soils     

Junu Shrestha  Jean Christophe Clément  Joan G. Ehrenfeld  Peter R. Jaffe 《Water, air, and soil pollution》2011,220(1-4):213-223

Riparian wetlands are subject to nitrogen enrichment from upgradient agricultural and urban land uses and also from flooding by nitrogen-enriched surface waters. The effects of this N enrichment on wetland soil biogeochemistry may be mediated by both the presence of plants and the presence of redox-active compounds, specifically iron oxides in the soil. Despite the extensive research on wetland N cycling, the relative importance of these two factors on nitrogen is poorly known, especially for forested wetlands. This study evaluates the responses of the N and the Fe cycles to N enrichment in a riparian forested wetland, contrasting vegetated field plots with plots where the vegetation was removed to test the role of plants. Furthermore, in vitro anaerobic incubations of the experimental soils were performed to track Fe chemical changes over time under anoxic or flooded conditions. Wetland soils treated with N in form of urea, as expected, had significantly higher amounts inorganic nitrogen. In the soils where vegetation was also removed, in addition to inorganic nitrogen pool, increase in organic nitrogen pool was also observed. The results demonstrate the role of vegetation in limiting the effects excess urea has on different soil nitrogen pools. Results from anaerobic incubation of the experimental soils demonstrated the effects of N enrichment on the wetland Fe cycle. The effects of excess nitrogen and the role of vegetation on the Fe cycle in riparian wetland soil became more evident during anaerobic incubation experiments. At the end of the field experiment, Fe concentrations in the soils under the treatments were not significantly different from the control soils at the 5% confidence level. However, during the anaerobic incubation experiment of soils collected at the end of the experiment from these plots, the N-enriched soils and the unvegetated soils maintained significantly elevated concentrations of reducible Fe(III) for the initial 2-week period of incubation, and the soils collected from the plots with both the treatments had the highest Fe(III) concentrations. After 20 days of incubation, however, the Fe(III) concentrations decreased to the similar concentrations in all the incubated soils. The study clarifies the roles vegetation play in mediating the effects of N enrichment and also demonstrates that N enrichment does affect wetland redox cycle, which has strong implications on ecosystem services such as water quality improvement.  相似文献   

Variability in sensory attributes in common bean (Phaseolus vulgaris L.): a first survey in the Iberian secondary diversity center     

Ana Rivera  Daniel Fenero  Antoni Almirall  Juan José Ferreira  Joan Simó  Marçal Plans  Roser Romero del Castillo  Francesc Casañas 《Genetic Resources and Crop Evolution》2013,60(6):1885-1898

Few studies have explored sensory variability in beans. We used geographic, agronomic, morphological, and genetic criteria to select numerous groups of landraces from among the many collected in Catalonia (northeast Spain). Beans cultivated in a single location to avoid environmental effects were submitted to a trained panel for sensory analysis. We used multiple linear regression to explore whether the flavor and texture of the seed (evaluable only by tasting after cooking) can be estimated from easily measurable traits like the appearance of the beans. The degree of variability found for all sensory traits (coefficients of variation: 20–70 %) was similar to that of agronomic traits; however, entries were grouped differently for sensory and agronomic traits, suggesting independent evolution. Negative genotypic correlations between some sensory traits will probably hinder attempts to achieve ideotypes combining low seed-coat perceptibility, low mealiness, and high flavor. Regressions between easily measurable traits (agronomic and culinary traits and appearance of the seeds) and flavor and texture yielded R² values ranging from 0.47 to 0.64. We consider these values good enough for rough screening of sensory attributes in genetic resources studies or breeding.  相似文献   

Factors involved in alleviating water stress by partial crop removal in pear trees     

Marsal J  Mata M  Arbones A  Del Campo J  Girona J  Lopez G 《Tree physiology》2008,28(9):1375-1382

We studied the relief of water stress associated with fruit thinning in pear (Pyrus communis L.) trees during drought to determine what mechanisms, other than stomatal adjustment, were involved. Combinations of control irrigation (equal to crop water use less effective rainfall) and deficit irrigation (equal to 20% of control irrigation), fruit load (unthinned and thinned to 40 fruits per tree) and root pruning (pruned and unpruned) treatments were applied to pear (cv. 'Conference') trees during Stage II of fruit development. Daily patterns of midday stem water potential (Psi(stem)) and leaf conductance to water vapor (g(l)) of deficit-irrigated trees differed after fruit thinning. In response to fruit thinning, gl progressively declined with water stress until 30 days after fruit thinning and then leveled off, whereas the effects of decreased fruit load on Psi(stem) peaked 30-40 days after fruit thinning and then tended to decline. Soil water depletion was significantly correlated with fruit load during drought. Our results indicate that stomatal adjustment and the resulting soil water conservation were the factors determining the Psi(stem) response to fruit thinning. However, these factors could not explain differences in daily patterns between g(l) and Psi(stem) after fruit thinning. In all cases, effects of root pruning treatments on Psi(stem) in deficit-irrigated trees were transitory (Psi(stem) recovered from root pruning in less than 30 days), but the recovery of Psi(stem) after root pruning was faster in trees with low fruit loads. This behavior is compatible with the concept that the water balance (reflected by Psi(stem) values) was better in trees with low fruit loads compared with unthinned trees, perhaps because more carbon was available for root growth. Thus, a root growth component is hypothesized as a mechanism to explain the bimodal Psi(stem) response to fruit thinning during drought.  相似文献   

Intra-plant variation in cyanogenesis and the continuum of foliar plant defense traits in the rainforest tree Ryparosa kurrangii (Achariaceae)     

Webber BL  Woodrow IE 《Tree physiology》2008,28(6):977-984

At the intra-plant level, temporal and spatial variations in plant defense traits can be influenced by resource requirements, defensive priorities and storage opportunities. Across a leaf age gradient, cyanogenic glycoside concentrations in the rainforest understory tree Ryparosa kurrangii B.L. Webber were higher in young expanding leaves than in mature leaves (2.58 and 1.38 mg g(-1), respectively). Moreover, cyanogens, as an effective chemical defense against generalist herbivores, contributed to a defense continuum protecting foliar tissue during leaf development. Chemical (cyanogens and phenolic compounds) and phenological (delayed greening) defense traits protected young leaves, whereas mature leaves were largely protected by physical defense mechanisms (lamina toughness; explained primarily by leaf mass per area). Cyanogen concentration was considerably higher in floral tissue than in foliar tissue and decreased in floral tissue during development. Across contrasting tropical seasons, foliar cyanogenic concentration varied significantly, being highest in the late wet season and lowest during the pre-wet season, the latter coinciding with fruiting and leaf flushing. Cyanogens in R. kurrangii appear to be differentially allocated in a way that maximizes plant fitness but may also act as a store of reduced nitrogen that is remobilized during flowering and leaf flushing.  相似文献   

Response of winter root starch concentration to severe water stress and fruit load and its subsequent effects on early peach fruit development   总被引：1，自引：0，他引：1  

Lopez G  Girona J  Marsal J 《Tree physiology》2007,27(11):1619-1626

Effect of water stress during stage III of peach fruit development on winter root starch concentration (RSC) and subsequent reproductive development was studied. Two irrigation treatments were applied in two consecutive seasons (2003-2004): full irrigation (FI) and no irrigation during stage III of fruit development until visible leaf wilting (LWI), which occurred when midday stem water potential reached -1.80 MPa. Three fruit thinning intensities were applied within each irrigation treatment. The year 2005 was a recovery year in which all trees received full irrigation and commercial fruit thinning. Water deficit and high fruit loads in the previous season significantly reduced the concentration of winter RSC. Fruit set and fruit growth from full bloom to 30 days after full bloom (30 DAFB) increased with increasing winter RSC before other factors, such as inter-fruit competition and availability of carbon from current photosynthesis, came into play. Consequently, severe water stress reduced the total number of fruits and fruit dry mass growth 30 DAFB. However, during the recovery year and after fruit thinning, fruit loads were similar between irrigation treatments and yield capacity remained unaffected. Peach fruit production recovered quickly from the deleterious effects of two consecutive years of water stress because of a combination of two factors: (1) reduced initial fruit set that was still adequate to achieve a commercial crop; and (2) the low sensitivity of fruit growth 30 DAFB to winter RSC.  相似文献   

Experimental Studies of Feeding in Larval Red Drum     

G. Joan  Holt 《Journal of the World Aquaculture Society》1992,23(4):265-270

The red drum ( Sciaenops ocellatus ) is the only marine fish species in commercial culture in the US. Red drum can be induced to spawn on demand at any time of the year and the young grown to marketable size in indoor raceways or in ponds. Although many eggs are produced (up to 1 million per spawning pair), grow-out through the larval stage remains a bottleneck in commercial production. Most larvae for commercial use are grown in outdoor ponds where natural blooms of phytoplankton and zooplankton are induced, but pond production is limited seasonally and geographically since red drum larvae require sea water and are intolerant of temperatures below 20 C.
It is possible to raise larvae indoors in tanks year-round by controlling temperature and salinity and by culturing live food, but not in sufficient number to supply commercial fish growers. Experimental studies are being carried out to modify the feeding and rearing systems to improve production of post-larvae. Of utmost importance is the development of a complete diet independent of live foods. Results of studies of highly unsaturated fatty acid requirements, digestive system development and activity levels of digestive enzymes are being incorporated into the development of an improved diet for red drum larvae.  相似文献   

Analysis of serum protein concentrations after severe thermal injury in a dog     

Kern MR  Stockham SL  Coates JR 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》1992,21(1):19-22

Serial serum electrophoreses and routine serum protein assays were used to assess changes in serum protein concentrations after severe thermal injury in a dog. Electrophoretic patterns during the month of evaluation were consistent with protein-losing dermatopathy (thermal burn) and inflammatory dysproteinemias.  相似文献   

Red‐light stimulation of boar semen prior to artificial insemination improves field fertility in farms: A worldwide survey     

Olga Blanco Prieto  Jaime Cataln  Marcel Lleonart  Sergi Bonet  Marc Yeste  Joan E. Rodríguez‐Gil 《Reproduction in domestic animals》2019,54(8):1145-1148

A survey of in vivo fertility data from 31 pig farms distributed worldwide was conducted to determine whether stimulating boar semen with LED‐based red light increases its reproductive performance following artificial insemination (AI). Red‐light stimulation with MaXipig^® was found to increase farrowing rates (mean ± SEM, control: 87.2% ± 0.4% vs. light stimulation 90.3% ± 0.5%) and the number of both total and live newborn piglets. Red‐light stimulation increased farrowing rates in 27 farms, with an increase ranging from 0.2% to 9.1%. Similar results were observed in litter sizes. Suboptimal management after AI was suggested in those farms with no response to red‐light stimulation. Our results indicate that a routine use of red‐light stimulation of boar semen can have a positive effect on the reproductive performance. However, the effectiveness of this system appears to highly rely upon proper management of pig farms.  相似文献   

Smithsonian Institution Center for Short-Lived Phenomena     

John Whitman  Joan Fenno 《Biological conservation》1974,6(4):308-311

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