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101.
Bahiagrass (Paspalum notatum) is a warm-season grass used primarily in pastures and along highways and other low maintenance public areas in Florida.
It is also used in landscapes to some extent because of its drought tolerance. Bahiagrass can survive under a range of moisture
conditions from no irrigation to very wet conditions. Its well-watered consumptive use has not been reported previously. In
this study, bahiagrass crop coefficients (K
c) for an irrigated pasture were determined for July 2003 through December 2006 in central Florida. The eddy correlation method
was used to estimate crop evapotranspiration (ETc) rates. The standardized reference evapotranspiration (ETo) equation (ASCE-EWRI standardization of reference evapotranspiration task committee report, 2005) was applied to calculate
ETo values using on site weather data. Daily K
c values were estimated from the ratio of the measured ETc and the calculated ETo. The recommended K
c values for bahiagrass are 0.35 for January–February, 0.55 for March, 0.80 for April, 0.90 for May, 0.75 for June, 0.70 for
July–August, 0.75 for September, 0.70 for October, 0.60 for November, and 0.45 for December in central Florida. The highest
K
c value of 0.9 in May corresponded with maximum vapor pressure deficit conditions as well as cloud free conditions and the
highest incoming solar radiation as compared to the rest of the year. During the summer (June to August), frequent precipitation
events increased the cloud cover and reduced grass water use. The K
c annual trend was similar to estimated K
c values from another well-watered warm-season grass study in Florida. 相似文献
102.
Gesto M Tintos A Alvarez R Soengas JL Míguez JM 《Fish physiology and biochemistry》2009,35(3):453-465
The contents of dopamine (DA), noradrenaline (NA), serotonin (5HT), and some related metabolites were studied in different
brain regions of rainbow trout at two different stages of sexual maturation (at the beginning of vitellogenesis), after naphthalene
(NAP) administration. The effects of NAP varied according to duration of exposure, brain region and vitellogenesis stage of
the trout, and were more significant during previtellogenesis. The changes observed in DA metabolism were generally stimulatory
after exposure for 3 h, and either stimulatory or inhibitory (depending on the brain regions) after exposure for 3 days to
NAP. NA levels were altered by NAP in various brain regions, but only during previtellogenesis. With respect to 5HT, treatment
with NAP reduced levels of the amine and/or its main metabolite in most of the brain regions studied, particularly 3 h after
treatment. The results suggest that NAP might interfere with the processes regulating brain monoamine metabolism, either locally
or indirectly by altering steroid feedback to brain centres, and thus disrupt endocrine control of reproductive development
through the brain–pituitary axis. 相似文献
103.
Poly(1-oxo-2-phenyltrimethylene) was successfully synthesized in the presence of palladium acetate and rare earth acetate
RE(OAc)3 (RE=Pr, Nd, Eu, Dy, Ho) multiplex catalyst system. The final products were characterized by elemental analysis, nuclear magnetic
resonance (NMR) and Fourier transform infrared spectroscopy (FTIR). The effects of various reaction parameters including molar
ratio of rare earth/Pd2+, methanol usage, 2,2-bipyridyl,p-toluensulfonic acid, andp-benzoquinone were studied in detail, and the influence of different rare earths on the copolymerization was also discussed.
It is found that the rare earths have favorable co-catalytic properties and palladium-rare earth multiplex catalyst showed
higher catalytic activity than palladium catalyst in the copolymerization of carbon monoxide (CO) and styrene (ST). 相似文献
104.
Kang-Le Lu Li-Na Wang Ding-Dong Zhang Wen-Bin Liu Wei-Na Xu 《Fish physiology and biochemistry》2017,43(1):65-76
High-fat diets may have favorable effects on growth and cost, but high-fat diets often induce excessive fat deposition, resulting in liver damage. This study aimed to identify the hepatoprotective of a Chinese herb (berberine) for blunt snout bream (Megalobrama amblycephala). Fish were fed with a normal diet (LFD, 5 % fat), high-fat diet (HFD, 15 % fat) or berberine-supplemented diets (BSD, 15 % fat with berberine 50 or 100 mg/kg level) for 8 weeks. After the feeding, histology, oxidative status and mitochondrial function of liver were assessed. The results showed that HFD caused fat accumulation, oxidative stress and apoptosis in hepatocytes of fish. Hepatocytes in HFD group appeared to be hypertrophied, with larger liver cells diameter than these of LFD group. Berberine-supplemented diets could attenuate oxidative stress and hepatocytes apoptosis. HFD induced the decreasing mitochondrial complexes activities and bulk density and surface area density. Berberine improved function of mitochondrial respiratory chain via increasing the complex activities. Moreover, the histological results showed that berberine has the potential to repair mitochondrial ultrastructural damage and elevate the density in cells. In conclusion, our study demonstrated that berberine has attenuated liver damage induced by the high fat mainly via the protection for mitochondria. 相似文献
105.
Carbon inventory methods and carbon mitigation potentials of forests in Europe: a short review of recent progress 总被引:1,自引:0,他引:1
The role of European forests and forest management in the carbon balance has received much attention in research recently.
This was particularly motivated by the recognition of forest management as one possible measure countries may adopt in the
framework of the Kyoto Protocol to reduce the concentration of greenhouse gases in the earth’s atmosphere. The main method
to assess carbon budget in forests is based on traditional forest inventories. This method requires the conversion of measured
stem volume to carbon pools. This conversion has been identified as a large source of uncertainty in past assessments. Over
the last 5 years, intensive research efforts have resulted in significant advances in the reliability of forest inventory
based carbon budgets. In parallel, the impact of forest management on the carbon balance of forest ecosystems has been investigated
and the carbon mitigation potential of these activities has been analysed. This paper reviews the progress that was made in
these two fields of research with a particular focus on European forests.
相似文献
Marcus LindnerEmail: |
106.
Frost tolerance is a main component of winter-hardiness and improving it would promote faba bean (Vicia faba L.) cropping in cool-temperate regions. In many species, leaf fatty acid composition was found to be related to frost tolerance.
The objective of this study was to determine, in a representative sample of genotypes, the effect of hardening on leaf and
stem (1) frost tolerance and (2) fatty acid composition, and to seek correlations between them. First leaf, second leaf and
stem of 31 faba bean genotypes were analyzed after hardening and without hardening. High frost tolerance of known winter genotypes
and several experimental lines was shown. Hardening had a significant, positive effect on frost tolerance of all three organs.
Stems were on average more frost tolerant than leaves. Hardening induced significant changes in the fatty acid composition:
oleic acid decreased significantly in leaves by 3.24% and in stems by 1.77%, whereas linolenic acid increased in leaves by
6.28% and in stems by 9.06%. In stems, correlations between frost tolerance and fatty acid composition were not significant.
Correlation coefficients strongly indicated that non-hardened oleic acid content, changes in oleic acid and in linoleic plus
linolenic acid content in leaves partly explained their frost tolerance; 0.347 (P < 0.1) < |r| < 0.543 (P < 0.01). The results corroborate the importance of using genetic differences in the fatty acid metabolism in breeding grain
legumes for frost tolerance. 相似文献
107.
We determined a suitable amount of fertilizer for konara oak(Quercus serrata) and Japanese zelkova(Zelkova serrata) planted in a harvested pitch pine(Pinus rigida) plantation. Two-year-old bare-root seedlings of konara oak and one-year-old containerized seedlings of Japanese zelkova were planted in April 2011. Three plots were established for each tree species to evaluate each of three fertilization applications. Solid compound fertilizer(N:P:K = 3:4:1) was applied yearly in three amounts(control: no fertilization, F1: 180 kg ha-1, and F2:360 kg ha-1), every May from 2011 to 2013. We measured the root collar diameter and height, and analyzed the compartmental N and P concentrations. Compartmental N concentrations of konara oak and Japanese zelkova were not consistent based on amount of fertilization. However,the compartmental P concentrations of konara oak and Japanese zelkova were significantly different in the order of F2, F1, and control. Although the differences in growth of konara oak appeared after 3 years of fertilization,Japanese zelkova showed differences after only 2 years of fertilization owing to differences in seedling type. Growth of konara oak was affected by fertilization at F1 and F2 in2013. However, growth of Japanese zelkova was affected only at F2. Nutrient demand of Japanese zelkova appeard to be higher than that of konara oak, at least during the early growing period. Results from this study could be practically used in harvested pitch pine plantations to determine appropriate fertilization regimes. 相似文献
108.
Ezenduka EV Oboegbulem SI Nwanta JA Onunkwo JI 《Tropical animal health and production》2011,43(3):557-559
The use of antimicrobial agents in poultry production results in their accumulation in the body tissues and products such
as milk and egg. The subsequent accumulation of these drugs and their metabolites in body cells is known as drug residue.
This study was designed to determine the prevalence of antimicrobial residues in eggs from poultry farms and retail outlets
in Enugu State, Nigeria. Eggs from 25 selected commercial farms and ten retail outlets were screened for the prevalence of
antimicrobial residue. Also, structured questionnaires were administered to 25 commercial farms in the state to determine
the management practices and the most widely used antimicrobial drugs in farms and possible association between the management
practices and the occurrence of antimicrobial residues in eggs from these farms. All the 25 farms surveyed use oxytetracycline.
Eggs from nine of the surveyed farms tested positive for antimicrobial residue and three of the ten surveyed farms also tested
positive for antimicrobial residue. No association was observed (p 0.05; Fisher’s exact test) between the occurrence of antibiotic residues in eggs and farm size, feed source and housing systems.
This study was able to demonstrate the presence of antimicrobial residues in eggs destined for human consumption. Drugs like
nitrofurans which has been banned for use in food animals are still very much in use in Enugu State, Nigeria. Antibiotics
given as feed additives may give rise to drug residues in food animals. 相似文献
109.
Shima Bagherabadi Doustmorad Zafari Yousef Moradi Amirabad Joyce H. C. Woudenberg 《Journal of General Plant Pathology》2017,83(6):398-401
Drimia maritima (squill) is a historically important medicinal plant. During the spring of 2016, small, yellow leaf spots, which became brown and finally necrotic, were observed on squill plants in Kohgiluyeh and Boyer-Ahmad Provinces in Iran. A fungus was consistently isolated from infected leaves and identified as Alternaria alternata based on morphological and phylogenetic analyses. Pathogenicity tests confirmed A. alternata to be the causal agent of the newly observed leaf spot disease. This is the first report of leaf spot on D. maritima caused by A. alternata in the world. 相似文献
110.
Hideaki Endo Tadayoshi Muramatsu Goro Yoshizaki Huifeng Ren Hitoshi Ohnuki 《Fisheries Science》2012,78(2):391-398
A label-free immunosensor for detecting the oocyte maturation-inducing hormone 17, 20β-dihydroxy-4-pregnen-3-one (DHP), was
developed. A principle of the sensor system was based on differences in electrochemical activity changed by an immunoreaction
in the absence and presence of DHP. For preparation of the immunosensor, anti-DHP IgG was immobilized on an Au working electrode
modified with a self-assembled monolayer of 3-mercaptopropionic acid. The sensor was immersed into a sample solution containing
DHP. DHP was determined by cyclic voltammetry. The immunosensor showed a specific response to DHP, and the oxidation peak
current linearly decreased in the range of 7.8–500 pg ml−1 with a correlation coefficient of 0.996. The sensor system was applied to determine the DHP levels in plasma of goldfish
and was compared with the DHP levels of the same samples determined using an ELISA as the conventional method. Good correlation
was obtained between values determined using both methods in the range of 0.1–7.7 ng ml−1 (correlation coefficient 0.876). These findings suggest that the proposed label-free immunosensor can be used to analyze
DHP levels in fish plasma samples. 相似文献