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941.
Eddy covariance (EC) systems are being used to assess the accuracy of remote sensing methods in mapping surface sensible and
latent heat fluxes and evapotranspiration (ET) from local to regional scales, and in crop coefficient development. Therefore,
the objective was to evaluate the accuracy of EC systems in measuring sensible heat (H) and latent heat (LE) fluxes. For this
purpose, two EC systems were installed near large monolithic weighing lysimeters, on irrigated cotton fields in the Texas
High Plains, during the months of June and July 2008. Sensible and latent heat fluxes were underestimated with an average
error of about 30%. Most of the errors were from nocturnal measurements. Energy balance (EB) closure was 73.2–78.0% for daytime
fluxes. Thus, daylight fluxes were adjusted for lack of EB closure using the Bowen ratio/preservation of energy principle,
which improved the resulting EC heat flux agreement with lysimetric values. Further adjustments to EC-based ET included nighttime
ET (composite) incorporation, and the use of ‘heat flux source area’ (footprint) functions to compensate ET when the footprint
expanded beyond the crop field boundary. As a result, ET values remarkably matched lysimetric ET values, with a ‘mean bias
error ± root mean square error’ of −0.03 ± 0.5 mm day−1 (or −0.6 ± 10.2%). 相似文献
942.
Siamak Rahmanpour David Backhouse Heather M. Nonhebel 《European journal of plant pathology / European Foundation for Plant Pathology》2010,128(4):429-433
The glucosinolate-myrosinase defence system, specific to Brassicales plants, produces toxic volatile compounds during mechanical
injury or pathogen attack. The reaction of this system to oxalic acid, known as a pathogenicity factor of Sclerotinia sclerotiorum, is not fully understood. The hydrolysis of glucosinolates was studied at varying conditions in the presence of oxalic acid
in the substrate. In a bioassay, colonies of the pathogen were exposed to volatiles from hydrated mustard powder used as a
myrosinase and glucosinolate source. The glucosinolate-myrosinase (GSL-M) system was activated in the presence of oxalic acid
at a concentration and pH similar to that expected in vivo. Volatile production was inhibited only when the pH fell to 3 or below. It is unlikely that oxalic acid plays a significant
role in disarming the GSL-M system during infection of Brassica hosts. 相似文献
943.
Quantitative trait loci for phytate in rice grain and their relationship with grain micronutrient content 总被引:6,自引:0,他引:6
James C. R. Stangoulis Bao-Lam Huynh Ross M. Welch Eun-Young Choi Robin D. Graham 《Euphytica》2007,154(3):289-294
Phytate (inositol-hexa-phosphate) has an important role in plants but it also may have anti-nutritional properties in animals
and humans. While there is debate within the plant breeding and nutrition communities regarding an optimum level in grain,
there appears to be little information at the molecular level for the genetics of this trait, and its association with important
trace elements, in particular, Fe and Zn. In this preliminary study, quantitative trait loci (QTL) for grain phytates, Zn
and Fe in glasshouse-grown rice lines from an IR64 × Azucena doubled haploid population were identified. Correlations between
phytate and essential nutrients were also studied. Transgressive segregation was found for most traits. Phytate and total
P concentrations had one QTL in common located on chromosome five with the (high concentration) allele contributed from Azucena.
There were significant positive correlations between phytate and inorganic phosphorus (P), total P, Fe, Zn, Cu and Mn concentrations
for both grain concentration and content. However, the QTLs of phytate were not located on the same chromosomal regions as
those found for Fe, Zn and Mn, suggesting that they were genetically different and thus using molecular markers in breeding
and selection would modify the phytate level without affecting grain micronutrient density. 相似文献
944.
The root parameters of forest trees can be indicators of a changing environment. We summarize the results of root studies
with regard to the effects of acidifying pollutants, especially soil acidification and aluminum toxicity, on various root
parameters of Japanese forest trees under experimentally controlled conditions. All root parameters such as biomass, morphology,
nutritional status, and physiology can be regarded as indicators, because, under laboratory conditions, root responses occur
prior to the responses in the aboveground parts. However, considering the conditions of forest sites, the nutritional status
and physiological changes are better indicators of soil acidification and Al stress than the biomass and morphological response.
The currently available data suggest that the most important indicator is the Ca/Al molar ratio in roots of Japanese tree
species. In order to predict and detect the initial effects of soil acidification, we postulate that the specific root response
to the Ca/Al molar ratio of tree roots should be considered as a parameter for use in long-term forest monitoring sites. 相似文献
945.
Jennifer A. Kimball Tan D. Tuong Consuelo Arellano David P. Livingston III Susana R. Milla-Lewis 《Euphytica》2017,213(5):110
Winter hardiness is a major-limiting factor for St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] grown in the transitional climatic region of the United States. Lab-based freeze tests that mimic the range of field winter survivability in St. Augustinegrass can contribute to the selection of cold hardy genotypes. This study used a whole container method, four freezing temperatures, and two data collection systems to evaluate the freezing response of nine St. Augustinegrass genotypes ranging in their winter hardiness. Results indicated ?3 and ?4 °C with average regrowth ratings of 33.6 and 17.8% respectively, were more suitable temperatures for evaluating freeze survival in St. Augustinegrass than ?5 and ?6 °C with average regrowth ratings of 0.4 and 0%, respectively. Visual ratings of surviving green tissue and regrowth were generally well correlated when evaluated over a six week period post-freeze with Pearson correlation coefficients ranging of 0.17–0.62 for ?3 °C freeze tests and 0.79–0.93 for ?4 °C freeze tests. Additionally, measurement of percent green cover using digital imaging techniques commonly utilized in turfgrass field studies were significantly correlated (0.66) with visual ratings averaged across weekly post-freeze evaluation measurements for both ?3 and ?4 °C freezing temperatures. These results provide evidence that digital imaging analyses are useful in estimating surviving green tissue and regrowth in lab-based freeze tests. This study provides additional information regarding freezing temperatures, genotype responses, and data collection methods in St. Augustinegrass, which should aid breeders in the improvement of freeze tolerance in the species. 相似文献
946.
The ability to discriminate local stocks of Japanese anchovy Engraulis japonicus was assessed based on data from four elements (K, Na, P, and Sr) using an electron probe micro analyzer (EPMA) and data from
three elements (Ba, Mn, and Sr) using inductively coupled plasma mass spectrometry (ICP-MS) from the otoliths of 40 anchovy
(23.6–47.0 mm body length). Anchovy were caught at three sites (Aki-nada, Hiuchi-nada, and Osaka Bay) in the Seto Inland Sea,
and one site (Kuroshio extension) in the Pacific Ocean in 2002. In order to discriminate different spawning grounds, EPMA
data from the core portion (from core to 30 μm in the core-posterior axis) were used. Results showed that it was difficult
to discriminate between the Seto Inland Sea and the Pacific anchovy by EPMA data. Conversely, it was possible to discriminate
between the Seto Inland Sea and the Pacific anchovy by ICP-MS data from bulk otoliths. Our results showed that Mn contents
of otoliths using ICP-MS discriminate between spawning grounds most, and Ba and Sr discriminate less. The difference in elemental
compositions in anchovy otoliths between the Seto Inland Sea and the Pacific Ocean might be reflected by cumulative experienced
elemental composition of ambient sea water during life history between the Seto Inland Sea and the Pacific anchovy. 相似文献
947.
Mariëlle L. van Toor Bart Kranstauber Scott H. Newman Diann J. Prosser John Y. Takekawa Georgios Technitis Robert Weibel Martin Wikelski Kamran Safi 《Landscape Ecology》2018,33(6):879-893
Context
High-resolution animal movement data are becoming increasingly available, yet having a multitude of empirical trajectories alone does not allow us to easily predict animal movement. To answer ecological and evolutionary questions at a population level, quantitative estimates of a species’ potential to link patches or populations are of importance.Objectives
We introduce an approach that combines movement-informed simulated trajectories with an environment-informed estimate of the trajectories’ plausibility to derive connectivity. Using the example of bar-headed geese we estimated migratory connectivity at a landscape level throughout the annual cycle in their native range.Methods
We used tracking data of bar-headed geese to develop a multi-state movement model and to estimate temporally explicit habitat suitability within the species’ range. We simulated migratory movements between range fragments, and calculated a measure we called route viability. The results are compared to expectations derived from published literature.Results
Simulated migrations matched empirical trajectories in key characteristics such as stopover duration. The viability of the simulated trajectories was similar to that of the empirical trajectories. We found that, overall, the migratory connectivity was higher within the breeding than in wintering areas, corroborating previous findings for this species.Conclusions
We show how empirical tracking data and environmental information can be fused for meaningful predictions of animal movements throughout the year and even outside the spatial range of the available data. Beyond predicting migratory connectivity, our framework will prove useful for modelling ecological processes facilitated by animal movement, such as seed dispersal or disease ecology.948.
Responses of species to landscape modifications are generally documented through their distribution at a given time along
an intensity gradient of land transformation. By focusing on patterns, we are limited to infer ecological processes occurring
within a system and its response to environmental disturbances which can further change over time. Using diachronic datasets
at the scale of France, we analyzed the spatial responses of the black-billed magpie, which has recently colonized cities,
to landscape urbanization. This study applied recently developed statistical approaches incorporating detection uncertainty
of the magpie, based on the capture-recapture statistical framework. We tested whether, and how, extinction and colonization
mechanisms influenced variations of magpie occupancy from 2001 to 2005. In addition, we assessed the importance of the recent
urbanization of the French countryside in determining population dynamics. Overall, our analysis proved that the proportion
of urban areas and recent urbanization in France led to an increase in the probability of magpie occupancy. Unexpectedly,
the species is concomitantly disappearing from the countryside, leading to a rapid change in the distribution of the species.
This study stressed the importance of incorporating detection uncertainty in inference process about spatial dynamics. Overall,
we show how useful it is to account for the dynamic evolution of the landscape in ecological studies. 相似文献
949.
Tássia Rhuna Tonial dos Santos Gustavo Affonso Pisano Mateus Marcela Fernandes Silva Carolina Sayury Miyashiro Leticia Nishi Murilo Barbosa de Andrade Márcia Regina Fagundes-Klen Raquel Guttieres Gomes Rosângela Bergamasco 《Water, air, and soil pollution》2018,229(3):92
The textile industries are characterized as one of the biggest consumers of potable water and chemical products throughout its process, being responsible for the elevated wastewater generation with intense coloration and wide polluting potential. In this context, the present study proposes the development and application of a new coagulant material for textile wastewater treatment. The proposed coagulant (α-Fe2O3-MO) was composed by hematite nanoparticles (α-Fe2O3) obtained by a simple non-pollutant methodology, associated with Moringa oleifera (MO) seeds saline extract compounds. Coagulation/flocculation (CF) efficiency was evaluated by removal of physicochemical parameters such as apparent color, turbidity, and compounds with absorption at UV254nm (UV254nm) through CF tests carried out on Jar test equipment and sedimentation carried out in the presence and absence of external magnetic field (600 k Am?1). Kinetics sedimentation was from 0 to 90 min. The use of this new coagulant allowed the removal of 92.37% for apparent color, 91.43% for turbidity, and 46.09% for UV254nm, indicating that the proposed coagulant association was efficient in the treatment of this type of wastewater under external magnetic field with only 10 min of sedimentation. In addition, the resulting sludge from CF process was tested as base material for a new coagulant synthesis, demonstrating great reuse potential. Therefore, the new proposed coagulant, composed of α-Fe2O3 and the compounds present in the seed extract of MO, has applicability for textile wastewater treatment demonstrating high removal rate for all evaluated parameters with cost reduction in the proposed treatment for this wastewater. 相似文献
950.
Anna Karczewska Karolina Lewińska Marcin Siepak Bernard Gałka Agnieszka Dradrach Katarzyna Szopka 《Journal of Soils and Sediments》2018,18(8):2749-2758