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排序方式: 共有233条查询结果,搜索用时 15 毫秒
91.
Monika Drážovská Katarína Šiviková Ján Dianovský Miroslav Horňák 《Animal Science Journal》2017,88(1):27-32
In this study, chromosomal imbalances in tumor tissues (lymphomas) and nucleotide changes in tumor suppressor TP53 were studied in a Bernese Mountain dog bitch and a cross breed bitch. Using comparative genomic hybridization, numerous chromosomal rearrangements were detected, which indicated the heterogeneity in tumor growth: in the cross breed bitch, a deletion on the chromosome 9, and duplications on chromosomes 5, 8 and 17 have been found. In the Bernese Mountain Dog bitch, losses on chromosomes 1, 5, 8, 12, 18, 22, 27, 29 and gains on chromosomes 1, 2, 9, 11, 15, 16, 18, 20, 23, 24, 25, 28, 29, 30, 34, 36, 37 and 38 were identified. With the sequencing of the TP53 gene, one silent mutation, transition A/G at position 138 in exon 5 was detected, without changing the amino acid. 相似文献
92.
Hana Bilošová Bořivoj Šarapatka Marie Štýbnarová Pavlína Mičová Marie Svozilová 《Archives of Agronomy and Soil Science》2017,63(11):1535-1545
This study shows the effect of organic fertilizers at different stocking rates, on nitrogen (N) leaching, measured using zero-tension lysimeters under undisturbed grassland soil. The experiment included two organic fertilizer types – cow dung with dung water (D) and slurry (S), both at a range of stocking rates: 0.9 LU (livestock unit) ha?1, 1.4 LU ha?1, 2.0 LU ha?1 (corresponding to 54, 84 and 120 kg N ha?1, respectively) and a control (C) treatment. In percolated water, the contents of ammonia nitrogen (NH4+–N) and nitrate nitrogen (NO3?–N) were studied. The average concentration of NH4+–N ranged from 0.91 to 1.44 mg l?1 on fertilized plots compared to 0.55 mg l?1 on the control plot. The average concentration of NO3?–N ranged from 5.2 to 9.5 mg l?1 on fertilized plots compared to 3.2 mg l?1 on the control plot. The results of this study showed that the use of organic fertilizers at chosen stocking rates influenced N leaching, but the concentration of N did not exceed the limits for drinking water permitted by Czech legislation. Stocking rates at 2.0 LU ha?1 and below do not result in elevated N concentrations in percolated water that pose environmental threat. 相似文献
93.
Lucia Kořenková Martin Šebesta Martin Urík Marek Kolenčík Gabriela Kratošová Marek Bujdoš 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2017,67(4):285-291
Since the fate of nanoparticles after their release in the environment and their possible transfer in plants and subsequent impacts is still largely unknown, this paper evaluates the potential phytotoxic effects of up to 20% w/w TiO2 nanoparticles (nTiO2) on barley cultivated in hydroponics and agar media. The X-ray diffraction analysis confirmed that nTiO2 powder corresponds to anatase phase. On agar medium only high concentrations of nTiO2 (10% and 20% w/w) induced significant inhibition of shoot growth. However, hydroponics treatment with nTiO2 up to 1000?mg?L?1 did not show any adverse effect on the shoot growth. In both experiments, (i) root growth inhibition effects became visible with increasing concentration of nTiO2, (ii) plants treated with nTiO2 showed no change in chlorophyll a and b content, even though the plants absorbed nTiO2, (iii) weight of biomass treated with nTiO2 was not significantly different compared to control. Therefore, we assume that transport of nTiO2 into the aerial parts is limited due to the presence of effective mechanical or physiological barriers in roots. Overall, it appears that early root growth is a relevant indicator of potential effects of nTiO2 exposure. Our results also indicate that synthesized nTiO2 are not significantly toxic to the barley when applied at the concentrations used in this work, even though plants absorb titanium. 相似文献
94.
Branimir Urlić Maja Jukić Špika Christine Becker Hans-Peter Kläring Angelika Krumbein Smiljana Goreta Ban 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2017,67(8):748-757
The effect of suboptimal supply of nitrogen (N) and of replacing nitrate in the nutrient solution with ammonia on growth, yield, and nitrate concentration in green and red leaf lettuce was evaluated over two seasons (autumn and spring) using multiple regression analysis. The plants were grown in a greenhouse on a Nutrient Film Technique (NFT) system. Nitrogen concentrations in the nutrient solution were either 3?mM or 12?mM, and the form of N was varied as follows: 100% NO3, 50% NO3?+?50% NH4, and 100% NH4. In both seasons, the biomass (fresh weight) of lettuce heads increased with increasing NO3 concentrations and in autumn, NO3 even at 1.5?mM was sufficient for high yield. However, head dry weight was affected neither by the season nor by changes in the composition of the nutrient solution. The concentration of NO3 had no effect on root dry weight, but it decreased at higher concentrations of NH4. The number of leaves increased as the ratio of NO3 to NH4 in the nutrient solution increased and was higher in autumn because of the longer growth period. Increasing the concentration of NO3 in nutrient solution increased both total N and nitrate concentration in lettuce heads (dry weight) but decreased the concentration of total C. Also, leaf nitrate concentration was lower in spring than in autumn and decreased with increasing NH4 concentration. Nitrogen utilization efficiency was maximum when NH4 levels in the nutrient solution were either 0% or 50% irrespective of the season. Our results thus show that suboptimal N supply in autumn will not affect lettuce yield, and that nitrate concentration in leaves is lower when NH4 concentrations in nutrient solution are higher and also much lower in red lettuce than in green lettuce. 相似文献
95.
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97.
Worldwide forests fragmentation has lead to a massive increase of habitat edges, creating both negative and positive impacts on birds. While busy highways dissecting forested areas create edges which are known to reduce bird densities due to the disturbing effect of noise, the impacts of logging forest roads with low traffic volumes have rarely been studied. In this study, we compared species richness and similarity of canopy, cavity and shrub guilds of birds along low-traffic forest roads, in forest interior, and at forest edges in secondary forests in central Europe, where the forests have passed through extensive changes toward uniformly compact growths dominated by production conifers. Although we found tree diversity as positively affecting bird richness across all habitats, the bird richness along forest roads was higher than in forest interior but lower than along forest edges. The shrub guild of birds along forest roads resembled this guild along forest edges while canopy and cavity guilds at the roads were more similar to these guilds in forest interior. Forest interior had the highest probability for some guild to be absent. We conclude that low-traffic roads lead to increase of habitat heterogeneity in structurally poor forests and attract birds due to additional habitat attributes—including better light conditions—that are scarce in forest interior. Therefore, broader support for higher structural diversification of uniform plantations in central European production forests would benefit bird communities inhabiting these areas. 相似文献
98.
Temporal changes of microbial respiration of leaf litter during gut passage by two species of bibionid flies (Penthetria holosericae and Bibio marci) and immediately after defecation were studied as well as the effect of B. marci feeding on microbial respiration in the remaining consumed leaf litter. Respiration in the guts of both species was lower than respiration of the original leaves. Microbial respiration increased after defecation, but respiration was higher in comparison with the original litter only for B. marci. Later, microbial respiration in both species decreased dramatically over several hours. Respiration of the remains of consumed leaves, from which the excrements were removed, was significantly higher than the respiration of non-consumed leaves. Scanning electron microscopy indicated that plant cells in the unconsumed part of the litter were massively broken-up by feeding activity and potentially exposed to microbial colonisation from the surrounding soil and microflora coming from the excrements deposited on the consumed litter. Long term (11 months) exposure of leaf litter and excrements produced from this litter showed that the decomposition of excrements was significantly slower than that of leaves. These findings indicate that bibionid feeding activity causes a short term increase in microbial mineralization of litter, but slows it down in the long term. 相似文献
99.
Comparison of numerical, analytical, and empirical models to estimate wetting patterns for surface and subsurface drip irrigation 总被引:2,自引:1,他引:1
Due to increasing competition for water resources by urban, industrial, and agricultural users, the proportion of agricultural
water use is gradually decreasing. To maintain or increase agricultural production, new irrigation systems, such as surface
or subsurface drip irrigation systems, will need to provide higher water use efficiency than those traditionally used. Several
models have been developed to predict the dimensions of wetting patterns, which are important to design optimal drip irrigation
system, using variables such as the emitter discharge, the volume of applied water, and the soil hydraulic properties. In
this work, we evaluated the accuracy of several approaches used to estimate wetting zone dimensions by comparing their predictions
with field and laboratory data, including the numerical HYDRUS-2D model, the analytical WetUp software, and selected empirical
models. The soil hydraulic parameters for the HYDRUS-2D simulations were estimated using either Rosetta for the laboratory
experiments and inverse analysis for the field experiments. The mean absolute error (MAE) was used to compare the model predictions
and observations of wetting zone dimensions. MAE for different experiments and directions varied from 0.87 to 10.43 cm for
HYDRUS-2D, from 1 to 58.1 cm for WetUp, and from 1.34 to 12.24 cm for other empirical models. 相似文献
100.
J. Plavec Ž. Budinšćak I. Križanac D. Škorić X. Foissac M. Šeruga Musić 《Plant pathology》2019,68(1):18-30
Flavescence dorée phytoplasma (FDp) is a quarantine pathogen associated with a severe and epidemic grapevine yellows disease representing a great threat for grapevine cultivation in Europe. An increase in disease spread prompted efforts to identify FDp strains in Croatia. Over 800 samples of grapevine together with presumed reservoir plants and almost 400 samples of Scaphoideus titanus and other potential vectors were collected countrywide and analysed. FDp isolates were characterized by multilocus sequence typing (MLST) of map, secY and uvrB-degV genes in order to determine genetic diversity and structure of FDp populations, and to trace transmission pathways. FD-related phytoplasmas were found in Croatia for the first time in alder, the invasive tree species Ailanthus altissima and leafhopper Phlogotettix cyclops. Phylogenetic analysis revealed the presence of three mapFD strain clusters: mapFD1, mapFD2 and mapFD3, and for the first time in Croatia a case of Palatinate grapevine yellows strain A (PGY-A). In total, 7 different map, 10 secY and 11 uvrB-degV genotypes were detected. The identification of 15 comprehensive FDp genotypes based on MLST suggests separate routes for disease introduction and propagation origins in Croatia. Moreover, high genetic variability of Croatian isolates indicates a complex ecological cycle of FDp involving various hosts. 相似文献