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51.
Marion A. Sonnleitner Madeleine S. Günthardt-Goerg Inga K. Bucher-Wallin Werner Attinger Sybille Reis Rainer Schulin 《Water, air, and soil pollution》2001,126(3-4):271-290
Sixteen open-top chambers, each equipped with two non-weighablegravity-drained lysimeter compartments, were used to investigate the impacts of elevated atmospheric carbon dioxide (CO2) concentration and nitrogen (N) deposition on the water relations and growth of young model forest ecosystems on two different types of soils. The same vegetation of a mixed spruce and beech overstorey and various herbs in the understorey was planted in all treatments on both soils. The soils were repacked on top of a drainage layer. Four combinations of treatments were applied in four replicates each: ambient (370 cm3 m-3) CO2 + low (7 kg N ha-1 a-1) N deposition, ambient CO2 + high(70 kg N ha-1 a-1) N deposition, elevated (590 cm3 m-3) CO2 + low N deposition, and elevated CO2 + high N deposition. After canopy closure, treatment effects on evapotranspiration and growth during the third year of study were very different for the two soils.On the acidic sandy loam, elevated CO2 enhanced growth(leaf biomass +21%, roots +27%) at reduced evapotranspiration (–9%). High N deposition increased aboveground growth even more strongly (+50%), but also increased evapotranspiration (+16%). Together, elevated CO2 and high N had a more than additive fertilizer effect on growth, while their effects on evapotranspirationcompensated. On the calcareous loamy sand, elevated CO2not only tended to enhance growth (leaf biomass +17%, roots +20%), but also increased evapotranspiration (+5%).On this soil, aboveground growth was stimulated by N only incombination with elevated CO2, but less than on the acidic soil, while evapotranspiration (–6.5%) and root growth into the subsoil (–54%) were decreased by increased N deposition at both CO2 concentrations, in contrast to the N treatments on the acidic sandy loam. The influence of the soil on the observed ecosystem responses canbe interpreted in terms of the concept of optimal resource allocation. 相似文献
52.
Jéssica Alves dos Santos Adriel Ferreira da Fonseca Gabriel Barth Renato Zardo Filho 《Archives of Agronomy and Soil Science》2018,64(2):173-184
The effects of lime application with multiple soil management methods and uses on dry matter (DM) yield and crude protein (CP) content of Silage maize cropping in succession with Italian ryegrass (ryegrass) from 2009 to 2014 in a southern Brazilian Oxisol were studied. The experimental design was completely randomized block in split-plot with four replications. The main plot treatments were the four soil management methods: conventional tillage (CT), minimum tillage (MT), no-tillage (NT) and chiseled no-tillage (CNT). The sub-plots treatments were the three uses of Italian ryegrass (ryegrass): cover crop (CC), silage (S), and grazing dairy heifers as part of integrated crop-livestock system (ICL). In all the years, the maize was sown approximately 30 days after the ryegrass desiccation with herbicide. In the medium-term (5 yrs.) after liming, soil management methods did not change DM yield and CP content in silage maize. The use of ryegrass for S and ICL did not change DM yield, but notably maintained or increased CP content in silage maize after liming. The use of ryegrass only as CC provided less measurable benefits than the combined production system of silage maize with ryegrass. 相似文献
53.
54.
Bruno I Cappellozza David W Bohnert Maria M Reis Kendall C Swanson Stephanie J Falck Reinaldo F Cooke 《Journal of animal science》2021,99(6)
This experiment evaluated the influence of protein supplementation frequency (SF) and amount offered on intake, nutrient digestibility, and ruminal fermentation by rumen-fistulated beef steers consuming low-quality [2.9% crude protein (CP); dry matter (DM) basis], cool-season forage. Seven Angus × Hereford steers (300 ± 27 kg) fitted with ruminal cannulas were randomly assigned to 1 of 7 treatments in an incomplete 7 × 4 Latin square. Treatments, in a 2 × 3 factorial design plus a non-supplemented control (CON), consisted of 2 levels of supplemental soybean meal, 100% (F) or 50% (H) of the estimated rumen-degradable protein requirement, provided daily (D), once every 5 d (5D), or once every 10 d (10D). Experimental periods were 30 d and dry matter intake (DMI) was measured from days 19 to 28. On days 21 (all supplements provided) and 30 (only daily supplements provided; day immediately prior to supplementation for 5D and 10D treatments) ruminal fluid was collected for ruminal pH, ammonia-N (NH3), volatile fatty acids (VFA), and determination of ruminal fermentation variables. Forage and total DM, organic matter (OM), and nitrogen (N) intake increased with supplementation (P ≤ 0.04). However, a linear effect of SF × amount of supplement interaction was observed for forage and total DM, OM, and N intake (P ≤ 0.04), with each variable decreasing as SF decreased, but the decrease being greater with F vs. H. Apparent total tract DM, OM, and neutral detergent fiber digestibility was not affected by supplementation or amount of supplement provided (P ≥ 0.10). In contrast, N digestibility increased with supplementation and for F vs. H (P < 0.01). Digestibility of DM, OM, and N increased linearly as SF decreased (P ≤ 0.03). When all supplements were provided, ruminal NH3, total VFA, and molar proportions of all individual VFA increased with supplementation (P ≤ 0.04), whereas acetate:propionate ratio decreased (P < 0.01). When only daily supplements were provided, none of the aforementioned fermentation parameters were affected (P ≥ 0.09). In summary, reducing the amount of supplemental CP provided to ruminants consuming low-quality forages, when supplementation intervals are >5 d, can be a management tool to maintain acceptable levels of DMI, nutrient digestibility, and ruminal fermentation while reducing supplementation cost. 相似文献
55.
Luis Alvarez-Lajonchegre Vinicius R. Cerqueira Israel D. Silva Jaqueline Araujo Marcosdos Reis 《Journal of the World Aquaculture Society》2002,33(4):506-516
A pilot‐scale trial to rear fat snook Centropomus parallelus through larval, weaning and nursery phases was conducted in Florianópolis, Brazil. Eggs (96% fertilization) from captive broodstock, induced to spawn using 50 μg/kg LHRHa were stocked in two 4,000‐L cylindrical fiberglass tanks at a mean density of 19.2 eggs/L. Nannochloropsis oculata was stocked with the eggs and maintained at a mean density of 0.5–1.0 ± 106 cells/mL up to 31 dph (31 dph). Hatching averaged 90%. Larvae were fed rotifers Brachionus rotundiformis enriched with an oil emulsion from 3 dph to 36 dph (30–40 rotifers/mL) and Artermia meta‐nauplii enriched with Selco from 22 dph to 60 dph (mean 2.9 meta‐nauplii/mL). Weaning began at 45 dph with an artificial dry diet NRG (50% protein), supplied together with concentrated and enriched Artemia meta‐nauplii. No critical period of mortality was observed during larval rearing. During the 43 days of weaning and nursery, less than 1% mortality was recorded. Food conversion rate during nursery was 1.17, with a change in the coefficient of variation of mean total length of 1.3%. Specific total growth rate in weight was 13.0 %/d and mean growth in total length and total weight were 0.65 mm/d and 24.0 mg/d over the whole rearing trial respectively. Mean total length and total weight of juveniles were 57.6 ± 0.1 mm and 2.11 ± 0.12 g, respectively, and the length‐weight relationship was W = 8.29931 ± 10–5 TL3.049607 (r= 0.9986). on 88 dph when the trial was terminated. The condition factor on 88 dph was 1.104. On 88 dph a total of 35,000 juveniles were harvested, overall survival was 25.5% with mean final density of 4.4 fishn and biomass of 6.9 kg/m3. The present trial demonstrated the feasibility of mass production of fat snook. Possible improvements necessary for commercial cultivation of fat snook C. parallelus are discussed. 相似文献
56.
The finer innervation of the tissues of the lung was studied with several methods of silver impregnation, focussing especially on the fibers and endings of the nerves. The richest terminal innervation could be found in the epithelial and subepithelial tissue, and was sometimes similar to the situation in the smooth muscles which might indicate that, somehow, secretory and motor innervation are alike morphologically. On the other hand, there were many nerve fibers in the perichondrium of the small nodules and plaques of cartilage too, although they did not enter the cartilaginous tissue. The final nerves ended in different forms, from round or ovoid masses to free "ultraterminal" filaments. 相似文献
57.
Fujiwara RT Bueno LL Vale AM Franca-Silva JC da Costa RT Quetz Jda S Machado-Coelho GL Reis AB Martins Filho OA Genaro O Nascimento E Mayrink W 《Polish journal of veterinary sciences》2005,8(1):17-22
Use of domestic reference values in the flow cytometry analysis is known to improve its accuracy by integrating local variations as gender, race and age. Up to date application of flow cytometry in veterinary medicine has been limited to describe the percentual values just for peripheral lymphocytes subsets of blood. We now report establishment of reference values for a wide range of proportional and absolute numbers of peripheral blood leukocytes, including T cells subsets, B cells, monocytes and eosinophils, applicable to the healthy population of Beagles in Brazil and other regions with similar demographic characteristics. Normal reference values were also established to estimate the gender-related differences. This information will provide clinical aid in the evaluation of immunologic status as well as standard values for experimental animals of dogs from Brazil and other similar regions. 相似文献
58.
N.?VovlasEmail author N.?J.?O.?Sim?es N.?Sasanelli M.?C.?V.?dos?Santos I.?M.?de?O.?Abrantes 《Phytoparasitica》2004,32(2):167-173
During a nematode survey, severe infections of tobacco feeder roots and heavy soil infestations byMeloidogyne incognita race 1 were found in S. Miguel (Azores islands, Portugal). This is the first record ofM. incognita infection of tobacco in Azores. Morphology of various life stages, analysis of the esterase electrophoretic pattern and differential
host tests were used for nematode characterization and identification. Nematode-induced mature galls were spherical and/or
ellipsoidal and usually contained more than one female, males and egg masses with eggs. Feeding sites were characterized by
the development of giant cells that contained granular cytoplasm and many hypertrophied nuclei. Giant cell cytoplasm was aggregated
along a thickened cell wall. Vascular tissues within galls appeared disorganized. The relationship between the initial nematode
population density and growth of tobacco plants was tested in a glasshouse experiment in which inoculum levels varied from
0 to 512 eggs and juveniles (J2) cm−3 of soil. Seinhorst’s model was fitted to height and top fresh weight data of the inoculated and control plants. Tolerance
limits with respect to plant height and fresh top weight of tobacco cv. ‘Erzegovina’ plants toM. incognita race 1 were estimated as 1.25 eggs and J2 cm−3 of soil. The maximum nematode reproduction rate was 404.7 at an initial population density of 4 eggs and J2 cm−3 of soil.
http://www.phytoparasitica.org posting March 2, 2004. 相似文献
59.
Roberto dos Santos Trindade Rosana Rodrigues Ant?nio Teixeira do Amaral Júnior Leandro Sim?es Azeredo Gon?alves Rogério Figueiredo Daher Cláudia Pombo Sudré 《Journal of General Plant Pathology》2012,78(3):201-206
Common bacterial blight (CBB) caused by Xanthomonas axonopodis pv. phaseoli (Xap) is the main bacterial disease of snap bean. The present work aimed to select snap bean genotypes that are resistant to CBB based on three components of resistance: area under the disease progress curve, latent period, and lesion diameter on pods (DL). A completely randomized two-factor factorial design with six replications was used to evaluate leaves and pods of 14 snap bean and three common bean genotypes (PI 207262, BAC-6 and A-794) with high resistance to CBB. Two Xap isolates, 1394-98 and 775-90, were used to inoculate leaves and pods. Data were analyzed using nonparametric statistics. Significant differences were observed among the evaluated genotypes for all of the components of resistance, except for DL. The snap bean UENF 1482 demonstrated good performance in two disease resistance components. For this reason, this genotype can be recommended for use in breeding programs that aim to generate snap bean genotypes resistant to Xanthomonas axonopodis pv. phaseoli. 相似文献
60.
RC Reis JM Miller MT Reynolds K Gültekin D Maitra AL King TE Strohmayer 《Science (New York, N.Y.)》2012,337(6097):949-951
Supermassive black holes (SMBHs; mass is greater than or approximately 10(5) times that of the Sun) are known to exist at the center of most galaxies with sufficient stellar mass. In the local universe, it is possible to infer their properties from the surrounding stars or gas. However, at high redshifts we require active, continuous accretion to infer the presence of the SMBHs, which often comes in the form of long-term accretion in active galactic nuclei. SMBHs can also capture and tidally disrupt stars orbiting nearby, resulting in bright flares from otherwise quiescent black holes. Here, we report on a ~200-second x-ray quasi-periodicity around a previously dormant SMBH located in the center of a galaxy at redshift z = 0.3534. This result may open the possibility of probing general relativity beyond our local universe. 相似文献