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41.
Spyra Marcin Kleemann Janina Cetin Nuket Ipek Vázquez Navarrete Cesar Jesús Albert Christian Palacios-Agundez Igone Ametzaga-Arregi Ibone La Rosa Daniele Rozas-Vásquez Daniel Adem Esmail Blal Picchi Paolo Geneletti Davide König Hannes J. Koo HongMi Kopperoinen Leena Fürst Christine 《Landscape Ecology》2019,34(7):1715-1735
Landscape Ecology - Several case studies investigated the role of ecosystem services in participatory planning processes. However, no systematic study exists that cuts across a large number of... 相似文献
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Endothelin‐1 Immunoreactivity and its Association with Intramedullary Hemorrhage and Myelomalacia in Naturally Occurring Disk Extrusion in Dogs 下载免费PDF全文
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Hiroto Yoshikawa Monique N. Mayer Kathleen A. Linn Ryan M. Dickinson Anthony P. Carr 《The Canadian veterinary journal. La revue veterinaire canadienne》2008,49(9):877-879
An 8-year-old, castrated male golden retriever was referred for lethargy and inappetance. Severe pain was elicited on palpation of the left temporomandibular joint region. Computed tomography revealed aggressive bone destruction of the left bulla. Squamous cell carcinoma was diagnosed. Malignant tumor in the canine middle ear is rare. 相似文献
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Lars A. Knechtenhofer Irene O. Xifra Andreas C. Scheinost Hannes Flühler Ruben Kretzschmar 《植物养料与土壤学杂志》2003,166(1):84-92
To assess the mobility of Pb and associated metals in a highly contaminated shooting range soil (Losone, Ticino, Switzerland), we investigated the spatial distribution of the metals and their relation to preferential water flow paths. A 2.2 m2 plot located 40 m behind the stop butt was irrigated with a solution containing bromide and Brilliant Blue, a slightly sorbing dye. A soil profile 50 cm in width was sampled down to 80 cm with a spatial resolution of 2.5 cm, resulting in 626 samples. Concentrations of elements (12 ≤ Z ≤ 92) were determined by energy‐dispersive Xray fluorescence spectrometry, and Brilliant Blue concentrations were determined with a chromameter. In the acidic (pH 3), organic matter‐rich, well drained Dystric Cambisol, maximum concentrations of 80.9 g kg‐1 Pb, 4.0 g kg‐1 Sb, and 0.55 g kg‐1 Cu were measured in the topsoil. Within 40 cm soil depth, however, Pb, Sb, and Cu approached background concentrations of 23 mg kg‐1, 0.4 mg kg‐1, and 9.4 mg kg‐1, respectively. The even horizontal distribution and the steep gradient along soil depth indicate tight metal binding in the topsoil, and a fairly homogeneous transport front. In contrast, water flow through the profile was highly heterogeneous. In the uppermost 20 cm, preferential flow was initiated by heterogeneous infiltration at the soil surface, but had no influence on metal distribution. Below 20 cm, however, preferential flow originated from larger tree roots, and metal concentrations were significantly elevated along these macropores. Spatial distributions of Pb, Sb, and Cu were similar, suggesting that all three metals are strongly retained in the topsoil and transported along preferential water flow paths in the subsoil. 相似文献
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Drought stress is the main factor limiting barley yields in West Asia and North Africa. This study compares the utility of doubled haploid lines (DHLs) and conventional F2 plant-derived bulks (F2Bs) in improving barley in stress environments. Double crosses were made, DHLs were developed by anther culture from double-cross F1 plants, and F2Bs were produced by bulking the offspring of F2 plants. Field tests were conducted in three drought-stressed environments. No major differences were observed in the mean performance of DHLs and F2Bs. For most traits, both the genotypic and the genotype × location interaction variances were higher in the DHL group, whereas heritabilities were similar. Higher gains from selection were predicted for the DHL group. Regression analysis of yield stability indicated a lower predictability of the DHL performance. The haploid technique can improve breeding populations from which varieties with stable yields can be developed. The costs involved are determined by the DHL production rate, which needs to be improved in many developing countries. 相似文献
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Summary Post-anthesis chemical desiccation of wheat (Triticum aestivum L.) plants in the field eliminates transtent photosynthesis by killing all green tissues, thus revealing the plant's capacity for grain filling from stored stem reserves, as the case is for post-anthesis stress such as drought or leaf diseases. This study was conducted to investigate whether mass selection for large kernels under chemical desiccation would lead to the improve ment of grain filling in the absence of transient photosynthesis.Six crosses of common spring wheat were subjected to three cycles of mass selection from F2 through F1 when selection was performed for large kernels by sieving grains from plants that were erther chemically desiccated after anthesis, or not (controls). The resulting 36 bulks (six crosses by three selection cycles by two selection environments) were compared with their respective F2 base populations, when tested with and without chemical desiccation.Selection for large kernels under potential conditions (without chemical desiccation) did not improve kernel weight under potnetial conditions, evidently because these materials were lacking in genetic variation for kernel weight under potential conditions. In four of the crosses, 3rd cycle selection for large kernels under potential conditions decreased kernel weight under chemical desiccation. On the other hand, selection for large kernels under chemical desiccation was effective in improving kernel weight and test weight under chemical desiccation, depending on the cross and the selection cycle, with no genetic shift in mean days to heading or mean plant height. Selection for large kernels under chemical desiccation was also effective in some cases in increasing kernel weight under potential conditions. The results are interpreted to show that selection under potential conditions and under chemical desiccation operate on two different sources for grain filling, namely transient photosynthesis and stem reserve utilization, respectively. In order to expose genetic variability for stem reserve utilization to selection pressure, transient photosynthesis must be eliminated, as done by chemical desiccation in this study. 相似文献
50.
Ole Wendroth Peter Jürschik K. Christian Kersebaum Hannes Reuter Chris van Kessel Donald R. Nielsen 《Soil & Tillage Research》2001,58(3-4):113-127
To evaluate the quality of the ecosystem and for making resources and land management decisions landscapes have to be assessed quantitatively. For a better understanding of landscape processes and their characterization, the analysis of the inherent variability is a major factor. Four case studies in which problems associated with landscape analysis are discussed. Spatial processes remain a main focus, as their analysis provides information on the relation between relevant state variables in agricultural landscapes. Variogram analysis showed that mineral soil nitrogen (Nmin) sampled in a field at different scales, domains, and times is an instationary spatial process. Spatial association of grain yield, soil index and remotely sensed vegetation index may not be identifiable from kriged contour maps as local coincidence may be obscured behind classified areas. Crop yield in subsequent years and remotely sensed information are not related if a unique response is assumed. An alternative data stratification procedure is described here for the identification of different response functions in agricultural ecosystems. Processes of crop yield and underlying variables are described in autoregressive state-space models. This technique incorporates both deterministic and stochastic relations between different variables and is based on relative changes in space. 相似文献