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1.
The effects of no‐till versus conventional farming practices were evaluated on soft wheat functional and nutritional characteristics, including kernel physical properties, whole wheat composition, antioxidant activity, and end‐product quality. Soft white winter wheat cultivar ORCF 102 was evaluated over a two‐year period from three long‐term replicated no‐till versus conventional tillage studies in Oregon. Wheat from the no‐till cropping systems generally had greater test weight, kernel diameter, and kernel weight and had softer kernels compared with wheat from the conventional tillage systems. Compared with the conventional systems, no‐till whole wheat flour had lower protein and SDS sedimentation volume. Ash content as well as most minerals measured (calcium, copper, iron, magnesium, and zinc), except for manganese and phosphorus, were generally slightly lower in no‐till than in conventional wheat. Whole wheat flour from the no‐till cropping systems generally had slightly lower total phenolic content and total antioxidant capacity. Milling properties, including flour yield, break flour yield, and mill score, were not affected by tillage systems. Refined flour from no‐till systems had lower protein, SDS sedimentation volume, and lactic acid and sucrose solvent retention capacities compared with flour from conventional tillage. No‐till wheat generally had greater sugar‐snap cookie diameter than conventionally tilled wheat. In conclusion, no‐till soft white winter wheat generally had slightly reduced nutritional properties (protein, ash, most minerals, and total antioxidant content) compared with wheat from conventionally tilled systems, and it had equivalent or sometimes superior functional properties for baking cookie‐type products.  相似文献   
2.
Chlorophyll fluorescence induction was used as a probe to detect herbicide detoxification in tolerant or susceptible wheat cultivars. Experimental conditions have been carefully examined for establishing detoxification kinetics of chlorotoluron and metribuzin, two photosystem-II-inhibiting herbicides. After a root treatment, leaves were cut, placed in glass tubes and maintained in the dark. The fluorescence induction rise was examined repeatedly and detoxification kinetics were established from these data for the same position on the individual leaves. The herbicide-dependent fluorescence rise decreased within hours in chlorotoluron-tolerant but not in susceptible Triticum aestivum cultivars. In contrast, no significant reversion could be detected after metribuzin application in both tolerant and susceptible cultivars of Triticum durum. Near the fluorescence-determined half-inhibition of photosystem II, linear detoxification kinetics were obtained in individual leaves, thus providing an accurate measurement of relative detoxification rates.  相似文献   
3.
Isolates of a soil Pseudoimonas, as well as other soil bacteria, showed a different sensitivity towards NO?2 when grown under aerobic or anaerobic conditions. The tolerance to NO?2 was increased in the presence of O2: for instance, a concentration of 200parts106 of NO?2-N proved to be toxic to a Pseudomonas sp. under anaerobic conditions, whereas over 400 parts106 were needed aerobically to suppress its growth completely. The addition of NO?3 as an electron acceptor for anaerobic respiration did not overcome the inhibitive effect of NO?3. The pH range, at which NO?2 was utilized anaerobically, was narrowed with increasing NO?2 concentration (pH 6.8–8.8 at 70 parts106 of NO?2-N and 7.4–8.5 and 140 parts106 of NO?2-N).Tolerance to nitrite varied considerably among the bacteria tested. Each species was able to overcome the inhibitory effect of NO?2 up to a certain concentration, while the length of the lag phase was related to NO?2 concentration.  相似文献   
4.
5.
We studied the effects of two fertilization treatments (N and NPKCa) on wood nitrogen (N) isotope composition (delta(15)N), water-use efficiency (WUE) estimated by carbon isotope composition (delta(13)C) analyses, and ring width of trees in 80-year-old beech (Fagus sylvatica L.) stands in the forest of Fougères, western France. Four replicates were fertilized in two successive years (1973 and 1974), 20 years before core sampling. Unfertilized control trees displayed a decreasing delta(15)N trend with time. The N and NPKCa treatments both increased delta(15)N compared with the control treatment. Wood extraction by organic solvents enhanced the delta(15)N signal. Thus, N addition to the beech ecosystem, even in moderate amounts, could be traced back in tree-ring delta(15)N, suggesting that wood N isotope analysis is a promising tool for studying the long-term effects of N deposition on forests. Although WUE decreased for about 6 years after N fertilization, WUE in NPKCa-treated trees did not differ significantly from that in control trees. Results were similar whether based on cellulose or total wood delta(13)C analysis, suggesting that extraction of cellulose is not necessary when studying fertilization impacts on WUE. The NPKCa treatment had a large impact on radial growth, causing a significant long-lasting increase of 29% compared with the control treatment. Nitrogen alone did not change radial growth significantly.  相似文献   
6.
We tested whether synchronous, long‐term fluctuations in Atlantic bluefin tuna (Thunnus thynnus) trap catches, collected from the ancestral Mediterranean and Atlantic trap fishery, might be related to large‐scale environmental change. Nine time series of trap catches of more than 80 yr long were compared with long time series of three preselected environmental variables, i.e. the North Atlantic Oscillation (NAO), the Length of the Day Index (LOD, a proxy of the atmospheric circulation index) and the temperature. Spectral analyses of trap catches, LOD and temperature displayed similar spectra with peaks at low frequencies, whereas those of the NAO exhibited a broad band spectrum. Regression analyses and tests of correlation did not reveal any clear relationship between trap catches on the one hand and NAO and LOD on the other hand. In contrast, long‐term fluctuations in trap catches appear to be closely and negatively related to long‐term trends in temperature. Underlying processes that could explain such a relationship are discussed, with special focus on changes in migration patterns of the Atlantic bluefin tuna.  相似文献   
7.
Major sugar and carboxylic acid components in apricot flesh fruits were detected and quantified. Fifty-one genotypes including clones growing in France, Spain, Italy, Greece and USA, belonging to the INRA germ plasm collection has been evaluated. Principal component analysis (PCA) has been performed to study correlation among fruit quality measurements and to interpret relationships between genotypes as a tool for germ plasm characterization. A marked variation in malic and citric acid content has been observed and PCA revealed clusters of apricot genotypes for the malic/citric ratio content. A good correlation between sugar component and refractometer index (r = 0.83) has been detected. The wide range of diversity in malic and citric acid content in apricot germ plasm makes it possible to breed and select genotypes with improved flavour on the basis of superior phenotypes. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
8.
Constructed ponds are an important consideration in the conservation of wetland biota in agricultural landscapes. Twenty-two natural ponds and 22 adjacent constructed ponds (farm dams) were surveyed on the Southern Tablelands of New South Wales to compare patterns of use by frogs and develop frog conservation recommendations. Farm dams supported similar numbers of frog species to natural ponds, although differences in frog assemblage were observed between the pond types. Limnodynastes tasmaniensis and Uperolia laevigata were significantly more likely to occur at farm dams while L. peronii was more likely to occur at natural ponds. Results suggest waterbodies with high levels of emergent vegetation cover that lack fish are likely to support a high number of frog species, regardless of origin (i.e. natural or constructed). However, it is important for landholders to conserve natural waterbodies as these environments appear likely to support frog species that do not use farm dams.  相似文献   
9.
Diurnal raptors were surveyed in Central Sulawesi on foot in 16 sample areas, and by car along 2700 km road transects in August-September 2000. All 23 resident species were recorded and their frequency of occurrence assessed in broad habitat categories. Farmlands were unusually poor in raptors. Of their six associated species, the formerly common black kite (Milvus migrans) may be almost extirpated. Indiscriminate pesticide use is suspected to be a major factor. Wetlands and sea-coasts are limited in area and are also the most heavily disturbed natural habitats. All four piscivorous eagles were found to be rare or very local. Among them, only the grey-headed fishing-eagle (Ichthyophaga ichthyaetus) was found to be more frequent than was previously known. Excessive human fishing pressure may be the main threat, together with extensive wetland conversion into ricefields or fishponds. Forest raptors (13 species), including all Sulawesi endemic Falconiformes, were the most numerous and widespread birds of prey. Although they exhibited a fairly high tolerance to forest degradation and fragmentation (insular syndrome), their main threat is the high deforestation rate, especially the loss of the presumably more productive lowland forests.  相似文献   
10.
Dimeric and polymeric hybrid oliogmers were obtained by the reaction of 2,6-xylenol and syringic acid in the presence of an enzyme from the fungus Trametes versicolor. Three hybrid dimers were formed in an assay at pH 4.5, while at pH 6.5, the formation of additional higher polymers with a phenyl-ether bond (tail to head linkage) was detected. The major product was identified as 3,5-dimethyl-3′,5′-dimethoxydiphenoquinone (4,4′), and it amounted to approximately 45% of the applied 2,6-xylenol after 3.5 hr incubation at pH 4.5. About 8% of the 2,6-xylenol was transformed to 4,4′-dihydroxy-3,5-dimethyl-3′,5′-dimethoxydiphenol and 22% to 3-methoxy-5-(2′,6′-dimethylphenoxy)-benzoquinone (1,2).  相似文献   
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