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41.
Fusarium oxysporum and Fusarium proliferatum are important causal agents of crown and root rot of asparagus. In order to detect differences in pathogenicity and aggressiveness, two F. proliferatum and five F. oxysporum single spore isolates from asparagus spears from plantings in Austria and Germany, 55 pure cultures of F. oxysporum from asparagus roots from a planting in Hesse, Germany, and a single F. oxysporum isolate from an asparagus shoot collected in Austria were evaluated in a 28-day quick test on Hoagland??s agar in glass culture tubes. Plantlets were inoculated with spore suspensions from each respective isolate after 14 days of growth under sterile, controlled conditions in a growth chamber. A severity scale was used to assess symptoms on roots two weeks after inoculation. The effects of the single-spore isolates on root and shoot fresh weights of the plantlets were also determined. The pathogenicity of the majority of the F. proliferatum and F. oxysporum isolates included in this study was confirmed. Inoculation with pure and single-spore cultures resulted in elevated disease severity in comparison to non-inoculated controls. In particular, the two F. proliferatum isolates were found to be more aggressive than the F. oxysporum isolates. Moreover, all single spore isolates caused a reduction in fresh weight of roots and shoots in comparison to the controls. With respect to differences among asparagus cultivars, ??Ramos??, was found to be more susceptible than ??Ravel??. Overall, the quick test method was found to be capable of evaluating the pathogenicity and aggressiveness of the tested F. oxysporum and F. proliferatum isolates towards asparagus within 28 days.  相似文献   
42.
Berry shrivel and bunch stem necrosis are the economically most important physiological disorders of grapevine. The nutritional status of the plant is considered as one of the main elicitors for the occurrence of these disorders. For foliar fertilization trials, two vineyards that had previously been affected by both diseases were selected in Southwest Germany, one with the variety ‘Zweigelt’ and one with Pinot Blanc. By the use of potassium, magnesium, and calcium foliar fertilizers, a rapid increase of different nutrients in the plants should be caused and the effects on the diseases observed. In 2010, no significant differences in the fertilization treatments were found for both varieties. In ‘Pinot Blanc’, significantly more berries were affected by berry shrivel in 2011 in plots treated with calcium fertilizer compared to those treated with potassium and magnesium. Plots with magnesium fertilizer showed significantly less berries affected by berry shrivel than the untreated control.  相似文献   
43.
ABSTRACT

Mineralization is the main organic matter conversion process, which leads not only to preservation of organic matter in the soil but also to its sequestration. Soil organic matter has equal value as mineral part if we want to improve soil quality or increase the yield. Because of intensive farming, irresponsible use of mineral fertilizers and natural factors, soil organic matter is decreasing. To counteract this process, different soil-friendly management practices and techniques, such as shallow tillage, no-tillage or direct drilling and application of additional organic matter are used. The objective of the present study was to assess the changes in the intensity of soil organic matter mineralization as influenced by primary soil tillage of different intensity in combination with organic matter incorporation. Long-term studies showed that land management practices differentiated the soil into two layers: upper (0–10?cm) layer containing more moisture and nutrients and lower (10–20?cm) layer comprising less moisture and nutrients. The conditions of aeration in the arable soil layer did not change under the effect of ploughing. In this soil, the rate of mineralization was lower than that in the ploughless tillage treatment. The most active mineralization of soil organic matter in the ploughless tillage treatment occurred in the autumn period, when high level of rainfall promoted the loss of nutrients from the topsoil layer.  相似文献   
44.
Dissolved concentrations of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in the influents and effluents of two municipal sewage treatment plants (STPs) were monitored over 16- (Umeå, Sweden) and 22- (?iauliai, Lithuania) day sampling periods. Sampling was performed using a passive sampling technique (semipermeable membrane devices; SPMDs) for sequestration of the dissolved (readily bioavailable) fraction of persistent organic pollutants (POPs). Removal efficiencies for individual low molecular weight (LMW) PAH compounds varied from 84% to levels at which the compounds were not detected in effluents from Umeå. The corresponding efficiencies of the ?iauliai plant were 33–95%. Measurements revealed that dissolved concentrations of most of the PCBs and some of the high molecular weight (HMW) PAHs increased during the conventional wastewater treatment at both plants. The release of dissolved PAHs and PCBs in the effluents from municipal wastewater treatment plants might increase the environmental contamination by readily bioavailable pollutants in the recipient waters; the rivers Umeälven and Kulpè. SPMDs were found to be suitable sampling tools for long-term (weeks-month) integrative monitoring of trace concentrations of the dissolved fraction of hydrophobic pollutants in the wastewater process, since the sampling and clean-up steps were easy to perform.  相似文献   
45.
A stable isotope dilution assay was developed for the quantitation of the potent onion odorant 3-mercapto-2-methylpentan-1-ol (1) using mass chromatography and synthesized [(2)H(2)]-3-mercapto-2-methylpentan-1-ol as the internal standard. Application of the newly developed method on onions from different origins revealed amounts between 8 and 32 microg/kg in raw onions, whereas 34-246 microg was found in sliced, stored (50 min), and then cooked onions. In extracts prepared by simultaneous steam distillation-extraction the highest concentrations of 1 were formed, amounting to >1200 microg/kg. The much higher content of 3-mercapto-2-methylpentan-1-ol in cooked onions suggested its formation from specific, yet unkown, precursors enzymatically formed during cutting of raw onions. 1 was for the first time identified and also quantified in other Allium species such as chives, scallions, and leek, whereas surprisingly garlic and bear's garlic did not contain the aroma compound.  相似文献   
46.
47.
The change of haptoglobin concentration in cattle with dystocia after torsio uteri which lead to Caesarean section is regarded in contrast to haptoglobin concentrations in cattle at parturitions with undisturbed puerperium and Caesarean section without torsio uteri intra partum. Animals with natural parturition had low haptoglobin concentrations with slight changes, for a slightly increased haptoglobin concentration was seen as physiologic. Also surgical treatment such as Caesarean section did not result in changes of haptoglobin concentration. Thus, the curve of animal patients with anomalies concerning position or with a too large fetus (relatively or absolutly) was nearly identical to the curve of animals with regular parturitions over the first four days after surgery. Not before the fifth day after surgery, a moderate increase of haptoglobin could be observed. Animals with dystocia after torsio uteri intra partum showed significantly higher haptoglobin concentrations in contrast to controls over the time of investigation. The correlation of haptoglobin concentrations in animal patients with torsio uteri bin concentration shortly after surgery an additionally significant increase of haptoglobin concentration could be observed in later fertile cattles but not in later infertile cattle with torsio uteri. In two cows with torsio uteri and ovariohysterectomy haptoglobin concentrations decreased rapidly. Haptoglobin concentration may serve as an indicator for the degree of impairment of the uterus during a parturition as well as a predictor for regenerative potential.  相似文献   
48.
The pathogenesis of equine urticaria is not well understood. In man, urticaria has been associated with immunological and nonimmunological mechanisms leading to the release of various mediators by mast cells. Skin biopsies of 32 horses with a history of urticaria were stained with toluidine blue, a double-labelling method for chymase and tryptase, and immunohistochemistry for immunoglobulin (Ig)E. These horses were compared with horses with pemphigus foliaceus, insect bite hypersensitivity and control horses with healthy skin. Neither formalin fixation time nor biopsy site influenced the staining methods. No chymase-positive cells were found. In all groups of horses, cells staining with toluidine blue and for tryptase and IgE were found in the epidermis and hair follicle papilla and significantly more positively staining cells were observed in the subepidermal dermis compared with the deep dermis. Horses with urticaria had significantly more IgE-bearing cells in the subepidermal dermis than control horses. However, horses with urticaria had significantly fewer toluidine-blue-stained mast cells in both subepidermal and deep dermis compared with the insect bite hypersensitivity and pemphigus foliaceus groups. This study suggests that IgE-mediated reactions play a role in the pathogenesis of urticaria.  相似文献   
49.
The prenatal development of the bovine ruminal epithelium was studied with light- and electronmicroscopical techniques. During the period of the nonstratified epithelium a pseudostratified epithelium is found in the dorso-cranial part, whereas the other areas possess a one-layered epithelium, which is, like the pseudostratified epithelium, transformed to a multilayered epithelium from the 7th week onwards. From the 9th week the period of the stratified epithelium starts with the formation of the stratum profundum and stratum superficiale. First signs of keratinization are seen in the superficial cells from 2.3 months onwards. With 4 months fetal cornified cells can be identified, with 5.5 months a single-layered stratum basale is seen on the differentiating papillar connective tissue, and the superficial cells are transformed to balloon-cells. In suprapapillar areas, a stratum spinosum is formed at the prenatal age of 7.5 months. During epitheliogenesis a horizontal and vertical differentiation of the cells can be observed. The first one includes the differentiation of undifferentiated, embryonal cells to the basal cells of the stratum profundum, the latter the development of the basal cells to spinous cells and then to fetal cornified and balloon-cells. The ultrastructural changes during the process of keratinization were especially considered.  相似文献   
50.
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