Phyllostachys praecox is one of the bamboo species used for the production of fine edible bamboo shoots and is widely distributed in Southern China.
To maintain or increase the productivity of bamboo shoots, P. praecox forests are intensively managed through heavy fertilization and surface mulch of organic residues such as rice husk to increase
soil temperature in the winter. Such management techniques can markedly influence soil quality and the dynamics of soil carbon
(C). The objectives of this study were to investigate the long-term impact of intensive management practices on carbon pools
and forms in the soil of bamboo forests and explore relationships between different soil organic C fractions, as little such
information is currently available. 相似文献
The aim of this study was to investigate the combined effects of soil moisture and temperature as well as drying/re-wetting and freezing/thawing on soil-atmosphere exchange of CO2 and CH4 of the four dominant land use/cover types (typical steppe, TS; sand dune, SD; mountain meadow, MM; marshland, ML) in the Xilin River catchment, China. For this purpose, intact soil cores were incubated in the laboratory under varying soil moisture and temperature levels according to field conditions in the Xilin River catchment. CO2 and CH4 fluxes were determined approximately daily, while soil CH4 gas profile measurements at four soil depths (5 cm, 10 cm, 20 cm and 30 cm) were measured at least twice per week. Land use/cover generally had a substantial influence on CO2 and CH4 fluxes, with the order of CH4 uptake and CO2 emission rates of the different land use/cover types being TS ≥ MM ≥ SD > ML and MM > TS ≥ SD > ML, respectively. Significant negative soil moisture and positive temperature effects on CH4 uptake were found for most soils, except for ML soils. As for CO2 flux, both significant positive soil moisture and temperature effects were observed for all the soils. The combination of soil moisture and temperature could explain a large part of the variation in CO2 (up to 87%) and CH4 (up to 68%) fluxes for most soils. Drying/re-wetting showed a pronounced stimulation of CO2 emissions for all the soils —with maximum fluxes of 28.4 ± 2.6, 50.0 ± 5.7, 81.9 ± 2.7 and 10.6 ± 1.2 mg C m−2 h−1 for TS, SD, MM and ML soils, respectively—but had a negligible effect on CH4 fluxes (TS: −3.6 ± 0.2; SD: 1.0 ± 0.9; MM: −4.1 ± 1.3; ML: −5.6 ± 0.8; all fluxes in μg C m−2 h−1). Enhanced CO2 emission and CH4 oxidation were observed for all soils during thawing periods. In addition, a very distinct vertical gradient of soil air CH4 concentrations was observed for all land use/cover types, with gradually decreasing CH4 concentrations down to 30 cm soil depth. The changes in soil air CH4 concentration gradients were in accordance with the changes of CH4 fluxes during the entire incubation experiment for all soils. 相似文献
We investigated the effectiveness of different inoculation approaches in enhancing the mineralization of [U-14C] labeled 1,2,4-trichlorobenzene (1,2,4-TCB) in soil. Inoculation was conducted with a soil-borne 1,2,4-TCB mineralizing microbial community (MC) as well as the Bordetella sp. strain F2 originally isolated from this community as the key degrader organism (IS). Both were applied either via liquid medium (LM) or attached on clay particles (CP). Fluorescence in-situ hybridization in combination with 14C-1,2,4-TCB mineralization measurements as well as measurements of 14C-residues in soil were used to investigate the bioaugmentation efficiency of the different approaches. Bordetella sp. cell numbers increased about 2-5 times during the incubation process, indicating that the bacteria could survive and develop in the new soil habitat. While the native soil showed negligible 1,2,4-TCB mineralization rates, soil inoculated with the MC attached on CP showed the highest 1,2,4-TCB mineralization rate per Bordetella cell, whereas the other inoculum approaches showed an increased but lower contaminant mineralization. Additionally, the MC-CP approach showed the highest cumulative 1,2,4-TCB mineralization as well as the highest formation of bound 14C-residues which is most likely equivalent to 14C incorporated into the microbial biomass. Thus, our results allow the conclusion that the application of a specific microbe-clay-particle-complex is the most promising approach for an accelerated in-situ mineralization of chemicals in agricultural soils. 相似文献
1. The objective of this study was to examine the beneficial effects of kaempferol, a naturally occurring polyphenol, on carcase characteristics in broiler chickens and the mechanisms involved in this regulation.
2. Broiler chickens were randomly divided into 7 groups: control, carrier control, kaempferol (0·3%), kaempferol (0·6%), hypercholesterolemic (HLD), HLD and kaempferol (0·3%), HLD and kaempferol (0·6%).
3. Seven weeks after treatment, carcase characteristics, lipid levels in the blood and liver, expression of hepatic Angiopoietin-like protein 3 (ANGPTL3) mRNA, and expression of adipose lipoprotein lipase (LPL) protein were determined.
4. Treatment with kaempferol (0·3 or 0·6%) significantly increased plasma high-density lipoprotein cholesterol levels, decreased percentage of abdominal fat, thickness of subcutaneous fat, plasma and hepatic total cholesterol and triglyceride concentrations, muscle malondialdehyde level and down-regulated expression of ANGPTL3 mRNA concomitantly with up-regulated expression of LPL protein in normal and hypercholesterolemic broiler chickens.
5. Kaempferol (0·3 or 0·6%) treatment had no significant effect on the values of percentage of breast muscle, percentage of leg muscle, carcase weight and eviscerated percentage.
6. The results suggest that kaempferol improves carcase characteristics by decreasing expression of ANGPTL3 in broiler chickens. 相似文献
The fatty liver of mule ducks (i.e., French "foie gras") is the most valuable product in duck production systems. Its quality is measured by the technological yield, which is the opposite of the fat loss during cooking. The purpose of this study was to determine whether biochemical measures of fatty liver could be used to accurately predict the technological yield (TY). Ninety-one male mule ducks were bred, overfed, and slaughtered under commercial conditions. Fatty liver weight (FLW) and biochemical variables, such as DM, lipid (LIP), and protein content (PROT), were collected. To evaluate evidence for nonlinear fat loss during cooking, we compared regression models describing linear and nonlinear relations between biochemical measures and TY. We detected significantly greater (P = 0.02) linear relation between DM and TY. Our results indicate that LIP and PROT follow a different pattern (linear) than DM and showed that LIP and PROT are nonexclusive contributing factors to TY. Other components, such as carbohydrates, other than those measured in this study, could contribute to DM. Stepwise regression for TY was performed. The traditional model with FLW was tested. The results showed that the weight of the liver is of limited value in the determination of fat loss during cooking (R(2) = 0.14). The most accurate TY prediction equation included DM (in linear and quadratic terms), FLW, and PROT (R(2) = 0.43). Biochemical measures in the fatty liver were more accurate predictors of TY than FLW. The model is useful in commercial conditions because DM, PROT, and FLW are noninvasive measures. 相似文献
Growth hormone is a major stimulator of skeletal muscle growth in animals, including cattle. In this study, we determined whether GH stimulates skeletal muscle growth in cattle by direct stimulation of proliferation or fusion of myoblasts, by direct stimulation of protein synthesis, or by direct inhibition of protein degradation in myotubes. We also determined whether these direct effects of GH are mediated by IGF-I produced by myoblasts or myotubes. Satellite cells were isolated from cattle skeletal muscle and were allowed to proliferate as myoblasts or induced to fuse into myotubes in culture. Growth hormone at 10 and 100 ng/mL increased protein synthesis in myotubes (P < 0.05), but had no effect on protein degradation in myotubes or proliferation of myoblasts (P > 0.05). Insulin-like growth factor-I at 50 and 500 ng/mL stimulated protein synthesis (P < 0.01), and this effect of IGF-I was much greater than that of GH (P < 0.05). Besides stimulating protein synthesis, IGF-I at 50 and 500 ng/mL also inhibited protein degradation in myotubes (P < 0.01), and IGF-I at 500 ng/mL stimulated proliferation of myoblasts (P < 0.05). Neither GH nor IGF-I had effects on fusion of myoblasts into myotubes (P > 0.1). These data indicate that GH and IGF-I have largely different direct effects on bovine muscle cells. Growth hormone at 10 and 100 ng/mL had no effect on IGF-I mRNA expression in either myoblasts or myotubes (P > 0.1). This lack of effect was not because the cultured myoblasts or myotubes were not responsive to GH; GH receptor mRNA was detectable in them and the expression of the cytokine-inducible SH2-containing protein (CISH) gene, a well-established GH target gene, was increased by GH in bovine myoblasts (P < 0.05). Overall, the data suggest that GH stimulates skeletal muscle growth in cattle in part through stimulation of protein synthesis in the muscle and that this stimulation is not mediated through increased IGF-I mRNA expression in the muscle. 相似文献
Two selection methods, 1-stage selection (OSS) and 2-stage selection (TSS), for improving efficiency and profitability of selective breeding of yellow perch were evaluated, through examining the genetic and phenotypic parameters for BW of F(1) fish using microsatellite parentage assignment in this study. Approximately 94% of the sampled yellow perch progeny were assigned to single parental pairs using 8 microsatellite markers, which confirmed the applicability of the communal rearing technique in yellow perch breeding. Within OSS, the genetic correlation between 1-yr-BW and 2-yr-BW was high (0.98), indicating that the growth of yellow perch recorded at yr 1 could predict their growth for yr 2. Also mean family BW and family EBV for BW between yr 1 and 2 were found to be significantly correlated, suggesting yr 1 fast-growing yellow perch families continued to be the fast growing families in yr 2. Two-year random fish undergoing TSS were significantly heavier (P < 0.01) than those undergoing OSS. In addition, top males and females with TSS were heavier (P < 0.01) than those with OSS. Based on these results we concluded that the TSS was more desirable and effective for yellow perch breeding compared with OSS in terms of improving selection efficiency and reducing costs. 相似文献
Objective: To determine the prevalence of radiographic signs of degenerative joint disease (DJD) in a randomly selected sample of domestic cats. Study Design: Prospective observational study. Animals: Client‐owned cats. Methods: Cats (n=100) from a single practice and equally distributed across 4 age groups (0–5; 5–10; 10–15, and 15–20 years old) were randomly selected (regardless of heath status) and sedated for orthogonal radiographic projections of all joints and the spine. Quasi‐Poisson regression analysis was used to investigate the relationship between patient demographics, blood biochemistry, hematologic and urine analysis variables, and DJD severity. Results: Most (92%) cats had radiographic evidence of DJD; 91% had at least 1 site of appendicular DJD and 55% had ≥1 site of axial column DJD. Affected joints in descending order of frequency were hip, stifle, tarsus, and elbow. The thoracic segment of the spine was more frequently affected than the lumbosacral segment. Although many variables were significantly associated with DJD, when variables were combined, only the association between age and DJD was significant (P<.0001). For each 1‐year increase in cat age, the expected total DJD score increases by an estimated 13.6% (95% confidence interval: 10.6%, 16.8%). Conclusion: Radiographically visible DJD is very common in domesticated cats, even in young animals and is strongly associated with age. Clinical Relevance: DJD is a common disease of domesticated cats that requires further investigation of its associated clinical signs. 相似文献