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171.
There is a need for simple, fast, efficient and sensitive methods of analysis for glyphosate and its degradate aminomethylphosphonic acid (AMPA) in diverse matrices such as water, plant materials and soil to facilitate environmental research needed to address the continuing concerns related to increasing glyphosate use. A variety of water‐based solutions have been used to extract the chemicals from different matrices. Many methods require extensive sample preparation, including derivatization and clean‐up, prior to analysis by a variety of detection techniques. This review summarizes methods used during the past 15 years for analysis of glyphosate and AMPA in water, plant materials and soil. The simplest methods use aqueous extraction of glyphosate and AMPA from plant materials and soil, no derivatization, solid‐phase extraction (SPE) columns for clean‐up, guard columns for separation and confirmation of the analytes by mass spectrometry and quantitation using isotope‐labeled internal standards. They have levels of detection (LODs) below the regulatory limits in North America. These methods are discussed in more detail in the review. © 2015 Society of Chemical Industry 相似文献
172.
Journal of Soils and Sediments - The aim of the study was to compare the activity, functional diversity, and community-level physiological profiles of soil microorganisms in light of soil physical... 相似文献
173.
Krystyna Zarzecka Marek Gugała 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2019,69(6):489-493
The objective of the study was to determine the effect of herbicides and biostimulants on the potato tuber content of nitrates. The experimental material consisted of tubers harvested in a field experiment which examined the following factors: three medium early potato cultivars (Bartek, Gawin, Honorata) and five methods of herbicide and biostimulant application (Harrier 295 ZC (linuron?+?chlomazon), Sencor 70 WG (metribuzin), growth regulator Kelpak SL (algae extract from Ecklonia maxima ? auxins and gibberellins), growth regulator Asahi SL (sodium para-nitrophenol, sodium ortho-nitrophenol, sodium 5-nitroguaiacol) and a control unit where weeds were mechanically controlled). The tuber content of nitrates was determined in fresh matter with an ion-selective nitrate electrode and silver–silver chloride reference electrode. Herbicides and biostimulants increased the potato tuber content of nitrates compared with control tubers. However, they did not pose a threat to consumer health. Tubers of plants sprayed with the herbicide Sencor 70 WG (metribuzin) and the biostimulant Asahi SL (sodium para-nitrophenol, sodium ortho-nitrophenol, sodium 5-nitroguaiacol) contained the most nitrates whose accumulation was also affected by cultivars and weather conditions in the study years. 相似文献
174.
The phytoestrogens genistein and daidzein had been found to affect the function of some tissues via oestrogen receptors (ER). In addition, genistein, but not daidzein, is considered to be a protein tyrosine kinase (PTK) inhibitor. Thus, the involvement of oestrogen receptors and PTK in phytoestrogen action on adrenocortical porcine steroidogenesis was examined in this study. The aims of the experiment were to test the effects of (i) ICI 182, 780 (ICI), an ER antagonist, on genistein- and daidzein-modulated cortisol and androstenedione (A4) secretion by adrenocortical cells isolated during the luteal and follicular phases of the porcine oestrous cycle; (ii) tyrphostin AG 957 (TAG), a nonsteroidal PTK inhibitor, on cortisol and A4 secretion by the cells and (iii) the phase of the porcine oestrous cycle on the mechanism of phytoestrogen action. Adrenals were harvested during the luteal (n = 5 animals) and follicular (n = 5 animals) phases of the oestrous cycle from locally slaughtered crossbred gilts. The isolated adrenocortical cells were incubated for 8 h (37 °C, 95% air, 5% CO2) with genistein (5 or 10 μM) or daidzein (5 or 10 μM) in the presence or absence of ICI (0.5 μM) or TAG (5 or 10 μM). Genistein and daidzein inhibited cortisol secretion and stimulated A4 secretion by porcine adrenocortical cells harvested during both the luteal and follicular phases of the oestrous cycle. The ER antagonist ICI did not eliminate phytoestrogen-induced changes in steroidogenesis. In contrast to genistein, TAG reduced the secretion of A4 and did not affect cortisol secretion. There was no observable effect due to the phase of the cycle. It is suggested that the mechanism of genistein and daidzein action in the adrenocortical cells of pigs is independent of ER and PTK. It is possible that PTK are involved in A4 secretion by porcine adrenocortical cells. 相似文献
175.
176.
Marek A Nolte V Schachner A Berger E Schlötterer C Hess M 《Veterinary microbiology》2012,156(3-4):411-417
The complete genome or the genome region containing the two fiber genes of two reference strains and one field isolate representing both serotypes of Fowl adenovirus C were sequenced. Two fiber genes were revealed in the genomes of all three isolates. Fiber-1 and fiber-2 genes of several Fowl adenovirus C isolates were sequenced as well. Both serotypes 4 and 10 have two fiber genes. The genome region containing the fiber gene was also sequenced for the reference strain of Fowl adenovirus B. Just one fiber gene was revealed in this strain. Predicted amino acid sequences were compared to already published fiber sequences of different adenovirus isolates and one amino acid substitution within fiber-2 was detected in all of the Fowl adenovirus C isolates that were isolated from chickens with hepatitis-hydropericardium syndrome in comparison to apathogenic isolates. Phylogenetic analyses provided insights about the evolution of fiber genes in avian adenoviruses and their genetic relationships. 相似文献
177.
Nitrous oxide and methane emissions from long-term tillage under a continuous corn cropping system in Ohio 总被引:1,自引:0,他引:1
Nitrous oxide (N2O) and methane (CH4) emitted by anthropogenic activities have been linked to the observed and predicted climate change. Conservation tillage practices such as no-tillage (NT) have potential to increase C sequestration in agricultural soils but patterns of N2O and CH4 emissions associated with NT practices are variable. Thus, the objective of this study was to evaluate the effects of tillage practices on N2O and CH4 emissions in long-term continuous corn (Zea mays) plots. The study was conducted on continuous corn experimental plots established in 1962 on a Crosby silt loam (fine, mixed, mesic Aeric Ochraqualf) in Ohio. The experimental design consisted of NT, chisel till (CT) and moldboard plow till (MT) treatments arranged in a randomized block design with four replications. The N2O and CH4 fluxes were measured for 1-year at 2-week intervals during growing season and at 4-week intervals during the off season. Long-term NT practice significantly decreased soil bulk density (ρb) and increased total N concentration of the 0–15 cm layer compared to MT and CT. Generally, NT treatment contained higher soil moisture contents and lower soil temperatures in the surface soil than CT and MT during summer, spring and autumn. Average daily fluxes and annual N2O emissions were more in MT (0.67 mg m−2 d−1 and 1.82 kg N ha−1 year−1) and CT (0.74 mg m−2 d−1 and 1.96 kg N ha−1 year−1) than NT (0.29 mg m−2 d−1 and 0.94 kg N ha−1 year−1). On average, NT was a sink for CH4, oxidizing 0.32 kg CH4-C ha−1 year−1, while MT and CT were sources of CH4 emitting 2.76 and 2.27 kg CH4-C ha−1 year−1, respectively. Lower N2O emission and increased CH4 oxidation in the NT practice are attributed to decrease in surface ρb, suggesting increased gaseous exchange. The N2O flux was strongly correlated with precipitation, air and soil temperatures, but not with gravimetric moisture content. Data from this study suggested that adoption of long-term NT under continuous corn cropping system in the U.S. Corn Belt region may reduce GWP associated with N2O and CH4 emissions by approximately 50% compared to MT and CT management. 相似文献
178.
Nicolas Caille Marek Rodina Martin Kocour David Gela Martin Flajšhans Otomar Linhart 《Aquaculture International》2006,14(1-2):75-87
The spermiation of tench males was stimulated with Supergestran containing mammalian LHRHa lecireline at the following doses:
5, 10, 20 and 40 g kg−1 b.w.; then with carp pituitary suspension (CPS) at a dose of 2 mg kg−1 b.w. and with a control of saline physiological solution. The following days, meaning 24, 48 and 72 h after injection, sperm
was collected to evaluate volume and the number of sperm per male per kg body weight (B.W.) The percentage of motile sperm
and velocity of spermatozoa were measured 48 h after hormonal injection, and 72 h after hormonal injection the sperm was evaluated
for fertilization and hatching ability. All 42 males in experimental groups were diploid. Live weight did not differ significantly
among experimental groups. The strongest stimulation of spermiation was achieved with LHRHa in dosage of 20 and 40 g kg−1 b.w. and CPS compared to males of the control group and lower dosage of LHRHa. Analysis of variance showed no significant
influence of the treatment on the velocity and percentage of motile spermatozoa. The effect of different treatment on the
fertilization capacity (the number of spermatozoa per egg was equilibrated) was significant. Significantly the highest quality
of sperm collected 72 h after injection expressed by percentage of fertilization and hatching (62–65% fertilization and 61–64%
hatching rates, respectively) was found for LHRHa in dosage of 20 and 40 g kg−1 b.w. Significantly the lowest parameters of fertilization and hatching were found for the control group, on the 12% level. 相似文献
179.
Radiation‐Use Efficiency,Biomass Production,and Grain Yield in Two Maize Hybrids Differing in Drought Tolerance
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B. Hao Q. Xue T. H. Marek K. E. Jessup X. Hou W. Xu E. D. Bynum B. W. Bean 《Journal of Agronomy and Crop Science》2016,202(4):269-280
Drought‐tolerant (DT) maize (Zea mays L.) hybrids have potential to increase yield under drought conditions. However, little information is known about the physiological determinations of yield in DT hybrids. Our objective was to assess radiation‐use efficiency (RUE), biomass production, and yield in two hybrids differing in drought tolerance. Field experiments were conducted in 2013 and 2014 with two hybrids, P1151HR (DT hybrid) and 33D49 (conventional hybrid) under well‐watered (I100) and drought (I50) conditions. I100 and I50 refer to 100 % and 50 % evapotranspiration requirement, respectively. On average, P1151HR yielded 11–27 % greater than 33D49 at I100 and about 40 % greater at I50, At I100, greater yield in P1151HR was due to greater biomass at physiological maturity (BMpm) resulting from greater post‐silking biomass accumulation (BMpost). At I50, both hybrids had similar BMpm but P1151HR showed a higher harvest index and greater BMpost. RUE differed significantly (P < 0.05) between the hybrids at I100, but not at I50. At I100, the RUE values for P1151HR and 33D49 were 4.87 and 4.28 g MJ?1 in 2013, and 3.71 and 3.48 g MJ?1 in 2014. At I50, the mean RUE was 3.89 g MJ?1 in 2013 and 3.16 g MJ?1 in 2014. Results indicate that BMpost is important for maintaining high yield in DT maize. 相似文献
180.
Distribution of lithogeneous, pedogeneous and anthropogeneous heavy metals in soils The study in hand shows relations between lithogeneously, pedogeneously and anthropogeneously enriched heavy metals and their concentration grades. Conclusions can be drawn from the vertical and horizontal distribution pattern of heavy metals on the nature and origin of their enrichment which is determined decisively by their mobility. Heavy metals enriched lithogeneously show relatively uniform as well as stratified concentration grades in the profile. A diminution of the heavy metal contents in all surface directions takes place starting from the centre of the lithogeneous enrichment. Pedogenetic processes lead to an increase of all element concentrations in certain soil horizons. Lateral transport causes an increase of heavy metal contents in the soils of low grounds compared with summits. Heavy metals enriched anthropogeneously are mostly accumulated in topsoils. Heavy metals concentrations due to dust immissions are characterized by a remarkable diminution of the concentration within the main wind direction. Heavy metal enrichments due to direct anthropogeneous charges are following the ground borders. 相似文献