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2.
An experiment was carried out to determine how the late application of nitrogen (N) fertilizer affects the use of pre‐anthesis carbon reserves during the grain‐filling period of pot‐grown wheat with no water shortage. Increasing doses (equivalent to 0, 140, and 180 kg N ha–1) of N fertilizer were applied, either in two amendments (stages GS20 and GS30) or in three amendments (stages GS20, GS30, and GS37, according to Zadoks scale). The management of fertilizer by combining an increased N rate with late N application was able to stimulate canopy development, to raise photosynthetic capacity and carbohydrate accumulation during the vegetative stages, and to increase grain yield. Based on the dynamics of carbohydrate accumulation in the ear, three phases were differentiated during the grain‐filling period, whose temporary pattern remained stable regardless of the fertilizer management. The net remobilization of carbohydrates started 12 d after anthesis from the leaves and 28 d after anthesis from roots and stems. The increase of the N dose with late N application allowed on one hand a lower use of the pre‐anthesis carbon reserves in favor of greater de novo photosynthesis during the grain‐filling period, and on the other hand greater relative contribution of the leaf and ear C reserves to remobilization towards the grain. Further splitting the dose increased only the relative contribution of ear C reserves. The stem contribution seemed to be independent of N applied whereas the root contribution tended to diminish with late N application.  相似文献   
3.
The uncalibrated predictive ability of four preferential flow models (CRACK‐NP, MACRO/MACRO_DB, PLM, SWAT) has been evaluated against point rates of drainflow and associated concentrations of isoproturon from a highly structured and heterogeneous clay soil in the south of England. Data were available for four plots for a number of storm events in each of three successive growing seasons. The mechanistic models CRACK‐NP and MACRO generally gave reasonable estimates of drainflow over the three seasons, but under‐estimated concentrations of isoproturon over a prolonged period in the first season and over‐estimated them in the two remaining seasons. CRACK‐NP simulated maximum concentrations of isoproturon over the first two events of each of the three seasons of 156, 527 and 24.4 µg litre?1, respectively, and matched the observed data (465, 65.1 and 0.65 µg litre?1) slightly better than MACRO (69.1, 566 and 58.5 µg litre?1). Automatic selection of parameters from soils information within MACRO_DB reduced the emphasis on preferential flow relative to the stand‐alone version of MACRO. This gave a poor simulation of isoproturon breakthrough and simulated maximum concentrations were 0, 50.1 and 35.1 µg litre?1, respectively. The capacity model PLM gave the best overall simulation of total drainflow for the first two events in each season, but over‐estimated concentrations of isoproturon (967, 808 and 51.3 µg litre?1). The simple model SWAT represented total drainflow reasonably well and gave the best simulation of maximum isoproturon concentrations (140, 80.2 and 8.2 µg litre?1). There was no clear advantage here in using the mechanistic models rather than the simpler models. None of the models tested was able to simulate consistently the data set, and uncalibrated modelling cannot be recommended for such artificially drained heavy clay soils. © 2001 Society of Chemical Industry  相似文献   
4.
An unusual case of multiple lymphangiomas with lymph node involvement is described. A seven-month-old, spayed female golden retriever was presented with a myriad of cystic masses in the inguinal and caudal mammary regions. She was diagnosed with congenital lymphangiomas (i.e., lymphatic hamartomas). As in human lymphangiomas, lymphatic endothelial cells expressing factor VIII-related antigen and smooth muscle were present in this case. A literature search did not identify similar characteristics in other reported canine lymphangiomas. The dog was treated surgically and had a recurrence. Following a second surgical intervention, she is now disease-free.  相似文献   
5.
Zusammenfassung Die Angaben eines 4jährigen Anbaus von zwei ingezüchteten Elternstämmen (buschförmigerCucurbita pepo L.) mit ihren F1- und F2-Generationen wurden für eine Analyse der Ertragskomponenten (reife Früchte) ausgewertet. Es wurde eingehend die Variabilität zwischen den Pflanzen, zwischen den Jahren und zwischen den Generationen verglichen und diskutiert. Folgende genetische Konsequenzen der Untersuchung sind wahrscheinlich:1. Die Anzahl der reifen Früchte je Pflanze ist stark umweltabhängig und zeigt eine Tendenz zu Heterosis.2. Das durchschnittliche Gewicht einer Frucht läßt sich am wenigsten von den Jahresbedingungen beeinflussen (hohe Heritabilität) und vererbt sich intermediär.3. Das daraus resultierende Gewicht der Früchte je Pflanze ist (wie die Fruchtanzahl) stark umweltabhängig; das hohe Fruchtgewicht vererbt sich aber dominant, wahrscheinlich deswegen, weil die Heterosistendenz der Anzahl der Früchte nicht genügend stark ist, um die konservative Heritabilität des Einzelfruchtgewichtes zu durchbrechen.4. Die Variabilität der F2-Generation war für alle Merkmale stärker als die der F1, die Mittelwerte der Merkmale aber waren für F1 und F2 nicht signifikant verschieden.
Summary Data of a four years growing of two inbred parent lines (Zucchini, bush,Cucurbita pepo L.) and their F1- and F2-generations have been used for an analysis of yield components (ripe fruits). Variability between plants, between years and between generations was thoroughly compared and discussed. The following genetic consequences of the investigation are probable:1. The number of ripe fruits per plant is highly dependent on the environment and shows a tendency towards heterosis.2. The mean weight of one fruit is least influenced by the conditions during the year (high heritability) and shows intermediary inheritance.3. The weight of the fruits per plant resulting from the above (as well as the number of fruits) is highly influenced by the environment; the high weight of fruits is dominant. The reason for this may be, that the tendency for heterosis concerning the number of fruits is not potent enough to break the conservative heritability of single fruit weight.4. The variability in F2 was found to be larger for all characters than in F1 but both generations showed no significant differences in the mean values of the characters tested.

F1, F2, (Cucurbita pepo L., ) 4 ; . , . , :1. ; .2. ( ); .3. , , ( ), , , , , , .4. F2 , F1, F1 F2 - .
  相似文献   
6.
Sensitivity analyses using a one-at-a-time approach were carried out for leaching models which have been widely used for pesticide registration in Europe (PELMO, PRZM, PESTLA and MACRO). Four scenarios were considered for simulation of the leaching of two theoretical pesticides in a sandy loam and a clay loam soil, each with a broad distribution across Europe. Input parameters were varied within bounds reflecting their uncertainty and the influence of these variations on model predictions was investigated for accumulated percolation at 1-m depth and pesticide loading in leachate. Predictions for the base-case scenarios differed between chromatographic models and the preferential flow model MACRO for which large but transient pesticide losses were predicted in the clay loam. Volumes of percolated water predicted by the four models were affected by a small number of input parameters and to a small extent only, suggesting that meteorological variables will be the main drivers of water balance predictions. In contrast to percolation, predictions for pesticide loss were found to be sensitive to a large number of input parameters and to a much greater extent. Parameters which had the largest influence on the prediction of pesticide loss were generally those related to chemical sorption (Freundlich exponent nf and distribution coefficient Kf) and degradation (either degradation rates or DT50, QTEN value). Nevertheless, a significant influence of soil properties (field capacity, bulk density or parameters defining the boundary between flow domains in MACRO) was also noted in at least one scenario for all models. Large sensitivities were reported for all models, especially PELMO and PRZM, and sensitivity was greater where only limited leaching was simulated. Uncertainty should be addressed in risk assessment procedures for crop-protection products.  相似文献   
7.
Sixteen dogs (2-12 years of age) presented with one (n = 15) or two (n = 1) cutaneous nodules (n = 16) or a dermal plaque (n = 1). Intact males (n = 9) and neutered males (n = 4) were more affected than were females (n = 3). Histologically, these lesions were characterized by focal dermal and subcutaneous deposition of thick hyalinized collagen fibers intermingled with fibroblasts, and in 13 of 17 lesions, a variable number of CD18-positive cells were interpreted as reactive macrophages. Fibroblasts in three dogs formed intersecting fascicles, interpreted as evidence of malignant transformation. The terms keloidal fibroma and keloidal fibrosarcoma can be applied to these lesions. Excision was curative in five dogs with keloidal fibroma for which follow-up was available. However, because malignant transformation may occur, wide excision of canine keloidal lesions is warranted.  相似文献   
8.
9.
Papillomaviruses (PVs) are highly species- and site-specific pathogens of stratified squamous epithelium. Although PV infections in the various Felidae are rarely reported, we identified productive infections in six cat species. PV-induced proliferative skin or mucous membrane lesions were confirmed by immunohistochemical screening for papillomavirus-specific capsid antigens. Seven monoclonal antibodies, each of which reacts with an immunodominant antigenic determinant of the bovine papillomavirus L1 gene product, revealed that feline PV capsid epitopes were conserved to various degrees. This battery of monoclonal antibodies established differential expression patterns among cutaneous and oral PVs of snow leopards and domestic cats, suggesting that they represent distinct viruses. Clinically, the lesions in all species and anatomic sites were locally extensive and frequently multiple. Histologically, the areas of epidermal hyperplasia were flat with a similarity to benign tumors induced by cutaneotropic, carcinogenic PVs in immunosuppressed human patients. Limited restriction endonuclease analyses of viral genomic DNA confirmed the variability among three viral genomes recovered from available frozen tissue. Because most previous PV isolates have been species specific, these studies suggest that at least eight different cat papillomaviruses infect the oral cavity (tentative designations: Asian lion, Panthera leo, P1PV; snow leopard, Panthera uncia, PuPV-1; bobcat, Felis rufus, FrPV; Florida panther, Felis concolor, FcPV; clouded leopard, Neofelis nebulosa, NnPV; and domestic cat, Felis domesticus, FdPV-2) or skin (domestic cat, F. domesticus, FdPV-1; and snow leopard, P. uncia, PuPV-2).  相似文献   
10.
The objective of this study was to determine the effect of an energy additive on the metabolism of cattle. This article provides information on the analysis of the diet of young cattle calculated for when the animals were both indoors and outdoors. The ration was prepared for 40 heifers, divided into 4 groups consisting of 10 animals in each group. Three of these groups were fed different amounts of a high-energy additive, which was not fed to the control group. The effectiveness of the additive was analyzed according to the balance experiment and by calculating digestibility coefficients. It was determined that the percentage of nitrogen use in young animals was higher in the groups that were fed the additive than in the control group. Increasing the dose of the additive increased the level of nitrogen use. Comparative analysis of live weight indicated intergroup differences in favor of heifers in the groups that were fed the additive of 1.34% to 2.41% at the age of 9 mo; 2.51% to 4.16% at 12 mo; 3.14% to 5.46% at 15 mo; and 3.57% to 6.30% at 18 mo. The average daily growth dynamics indicated a gradual increase in all animals up to 15 mo, with a slight decrease by 18 mo of age. The difference among the groups ranged from 5.08% to 8.85% at 6 to 9 mo of age; 7.08% to 10.79% at 9 to 12 mo; 5.64% to 10.97% at 12 to 15 mo; and 6.05% to 11.11% at 18 mo. It was concluded that feeding the energy additive Tanrem to heifers increased their metabolism so that nitrogen use was improved, and feed was digested more efficiently, which in turn improved the growth of animals. Using an energy additive at the mid-range dose of 500 g a day per animal is recommended, since the effect was similar at the mid-range and maximum dosages.  相似文献   
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