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Three types of alpine plant species,Carex montis-everestii,Quercus aquifolioidesandStipa capillacea, along an altitudinal gradient of 3005–5025 m on the Tibetan Plateau, were chosen to test the generality of the hypothesis that foliar carbon isotope composition (δ¹³C) of C3 plants increases significantly with altitude and to determine climate drivers shaping its altitudinal pattern. Temperature and relative humidity showed significantly negative correlations with altitude; however, precipitation and soil water potential remained unchanged with altitude. Foliar δ¹³C of C. montis-everestii,Q. aquifolioides,S. capillaceaalone or combined together did not significantly increase with altitude, which does not support the leading hypothesis of increased foliar δ¹³C with altitude. There was no difference in foliar δ¹³C among all three species. Multi-factor correlation analyses showed that temperature, precipitation and relative humidity alone did not affect foliar δ¹³C ofC. montis-everestiiandS. capillacea, but conferred significant effects on foliar δ¹³C of Q. aquifolioides.
In order to investigate the concentrations of selenium (Se) in plants of the Dashan Region, a typical Se-rich area of China, and to illuminate the daily dietary Se intake of residents in this region, 83 crop samples and 144 Chinese herb samples were collected. Total Se was analyzed in the edible portion of crops and the medical portion of Chinese herbs. The average concentrations of Se ranged from 100 to 3,100 μg kg⁻¹ (dry weight/DW) in different crops and from 20 to 1,500 μg kg⁻¹ in the Chinese herbs (DW). The crop that contained the highest concentrations of Se was radish, while maize contained the lowest levels. For the Chinese herbs, the highest concentrations of Se were found in Rumex japonicas, while Cape jasmine contained the lowest levels of Se. The average enrichment coefficients (ECs) were 6.1-300% in crops, and 1.6⁻¹17% in Chinese herbs. Among the crops, radish had the highest EC (300%), while pumpkin had the lowest (6.1%). Among the Chinese herbs, Sapium sebiferum had the highest EC (117%), while Dicranopteris dichotoma had the lowest (1.6%). Based on the composition of residents’ daily diets, the estimated daily Se intake from crops was 282±20 μg day⁻¹, and was about 5 times higher than the RDA value suggested by WHO (55 μg day⁻¹). Although no selenosis incidents have occurred in the Dashan Region to date, the potential health risk caused by chronic exposure to high levels of Se cannot be ignored.
A vailability and heterogeneity of resources have a strong influence on community biomass and diversity, which provided a valuable opportunity to evaluate the responses of vegetation on fertilization, to test whether fertilisation can accelerate vegetation restoration in infertile lands. In loess hilly region of China, most newly abandoned infertile lands often undergo heavy soil erosion. It is urgent to promote the restoration of these types of lands. As availability and heterogeneity of soil nutrients have a strong influence on plant community, we conducted a fertilisation experiment with three-factor treatments, to test whether fertilisation can promote the biomass and species richness of an Artemisia scoparia-dominated old field community. The three factors were: spatial patterns (homogeneity and heterogeneity), levels (low, medium and high), and scales (three levels with small, intermediate, and large patches) of fertiliser application. Aboveand below-ground biomass and species richness were recorded. The responses of the plant community to the three factors were evaluated and compared with those of the control (no fertilisation). The results show that: (1) The application of fertiliser in either homogeneous or heterogeneous pattern significantly increased the above-ground and below-ground biomass of the plant community as compared with the control. (2) In heterogeneous conditions, the above-ground biomass in nutrient-rich patches was significantly greater than the expected value of 50%. Under intermediate and large scales of the low level and all scales of the medium and high levels, the proportion of 0–15 cm below-ground biomass was also significantly greater than 50%. (3) Both homogeneous and heterogeneous fertilisation greatly increased community richness as compared to the control. Fertilisation, particularly heterogeneous fertilisation, can effectively increase community biomass and diversity. Under patchy habitat, it seems that the responses of vegetation to heterogeneous fertilisation are related to the patches scale and the contrast among patches, nutrient usage efficiency, edge effects on plant and soil, and plant competition are responsible for the responses. The results also suggest that heterogeneous fertilisation should be applied widely in infertile old fields to accelerate secondary succession.
Voronoi area of coexisting species in a community has an important role in determining their performances as it is related with the available resources around individuals. Biomass formed within certain Voronoi area probably can be a mark of species that characterised resource competition ability of coexisting species in natural community. In this article, we tried to probe the subject in the following three aspects: 1) what is the apparent relationship between individuals’ aboveground biomass and their available Voronoi area for species in natural community? 2)what is the possible theoretic relationship between them? 3) additionally, whether there are any possible indices that can be elicited from species’ occupied Voronoi area to reflect species’ competitive ability. Using individual-based investigation of aboveground biomass and their corresponding positions, Voronoi area of all individuals of coexisting species in an old field community were computed. The growth of an individual could be regard as a process to compete for resources that is limited by the available area or volume encompassed by the neighborhood individuals. We extended logistic growth model to describe the relationship between Voronoi area and aboveground biomass of coexisting species by relating limiting rhizospheral resource with the Voronoi area around an individual. Theoretically, the individual’s aboveground biomass is also controlled by factor-ceiling effects of Voronoi area. So the extended model was fitted with boundary analysis method. And also, their linear relationship was fitted. Under the prediction that competive ability is one of the main driving factors of community succession, two parameters as the Voronoi area of coexisting species and the Voronoi area per unit of aboveground biomass were used to check whether they can designate species’ competitive abilities and competitive hierarchies. This was presented by fitting the two parameters with the successional niche positions that was represented by the ordination values along abandonment ages of old field communities in the local area. The results showed that: 1) For most species, the linear regression demonstrated that Voronoi area of an individual that occupied larger Voronoi area tended to have greater aboveground biomass. The nonlinear regression of showed that the relationship might depend upon species’ growth characteristics, like shade tolerance and root proliferation. Generally, the relationship could be better fitted by the extended logistic growth model using boundary analysis method than by the linear regression, except for some shade-preferring or clone species. If factor-ceiling effects were considered, at the highest, about 48% of the variation of aboveground biomass could be interpreted by Voronoi area. For some other species with light preference or clone proliferation, the determination coefficient was around zero. 2) Species’ averaged Voronoi area had significant and positive Kendall’s tau-b and Spearman correlations with successional niches, and species’ per-unit aboveground biomass positions of Voronoi area has significantly negative rank correlation with successional niche positions. These indicate that both of them can reflect species’ competitive ability and hierarchy to some extent.
The environmental challenge of crude oil-contaminated soil is difficult to address due to its complicated components and the mechanism of material transformation. In order to study the bioremediation of soil contaminated by crude oil, we designed five simulation test systems: a sterilization system, an oxygenated and water-controlled system, a nitrogen (N)/phosphorus (P) adjusted system, a broth-added system, and a double-broth-added system. The results show that the highest removal of crude oil from soil was increased to 34.23% by regulating the micro-ecological environment after 91 days in a simulation system. Regulating N and P can effectively strengthen the mineralization action of microorganisms on crude oil. Biodegradation had the most effect on the removal of oil, accounting for more than 58% of the total removal. Moreover, mineralization was dominant in biodegradation. Degradation of crude oil components was alkanes-based, accounting for 50 to 80% of total oil removal. By regulating moisture, temperature, oxygen content, N/P levels, and enrichment broth, the half-life of crude oil in a simulation system can be shortened to 182 days.
Assessing the risks of steering system faults in underwater vehicles is a human-machine-environment (HME) systematic safety field that studies faults in the steering system itself, the driver’s human reliability (HR) and various environmental conditions. This paper proposed a fault risk assessment method for an underwater vehicle steering system based on virtual prototyping and Monte Carlo simulation. A virtual steering system prototype was established and validated to rectify a lack of historic fault data. Fault injection and simulation were conducted to acquire fault simulation data. A Monte Carlo simulation was adopted that integrated randomness due to the human operator and environment. Randomness and uncertainty of the human, machine and environment were integrated in the method to obtain a probabilistic risk indicator. To verify the proposed method, a case of stuck rudder fault (SRF) risk assessment was studied. This method may provide a novel solution for fault risk assessment of a vehicle or other general HME system
In this assay, we developed and evaluated a multiplex PCR (mPCR) for its ability in detecting multiple infections of swine simultaneously. Four pairs of primers were used to detect five viruses. Specific primers were designed for classical swine fever virus (CSFV), African swine fever virus (ASFV) and pseudorabies (PRV). A pair of primers was designed prudently for two different types of porcine reproductive and respiratory syndrome virus that respectively were porcine reproductive and respiratory syndrome virus (PRRSV), highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV). The detection limits of the mPCR were 1.09×10⁴, 1.50×10³, 2.10×10³, 1.30×10³ and 8.97×10² copies/reaction for CSFV, ASFV, HP-PRRSV, PRRSV and PRV, respectively. A total of 49 clinical specimens were tested by the mPCR, and the result showed that co-infection by two or three viruses was 51%. In conclusion, the PCR is a useful tool for clinical diagnosis of not only single infections but also mixed infections in swines.
Low light is one of the most important factors affecting cucumber growth in winter solar greenhouses in northern China. Whether induction light intensity has an effect on expressions of rbcL, rbcS and rca genes in cucumber leaves grown under low light for long periods of time remains unclear. Here, two genotypes of cucumber were used to determine the effects of growth and induction light levels on photosynthetic induction. It was found that regardless of growth and induction light intensity, the transcript levels of rbcL, rbcS and rca increased quickly once the plant was exposed to light. The variations of the photosynthesis (PN), stomatal conductance (gₛ), actual photosystem II efficiency (ΦPS II) and Rubisco activity were similar to transcript levels. Plants grown at a photon flux density (PFD) of 100 µmol m⁻² s⁻¹ had lower PN, and initial and total Rubisco activity than those grown at 600 µmol m⁻² s⁻¹ , regardless of induction PFD; for plants grown at the same PFD, PN, gₛ and Rubisco activation rate induced under PFD of 100 µmol m⁻² s⁻¹ were lower than those under 600 µmol m⁻² s⁻¹ . Rubisco, especially RCA, played a great role on photosynthesis during photosynthetic induction. Compared with Jinyan No. 2, Deltastar may possess potential low-light tolerance with a lower decrease of PN, and initial and total Rubisco activities when grown and induced at 100 µmol m⁻² s⁻¹ than 600 µmol m⁻² s⁻¹ . Moreover, the mechanism of Rubisco activase in regulating Rubisco during photosynthetic induction is also discussed.
Investigations were carried out to study the responses of canola (Brassica napus) under contrasting temperature regimes (day/night C): 35/30 (high temperature) and 15/10 (low temperature) in comparison with optimal temperature (25/20) at early seedling stage. The results indicated that high temperature inhibited seedling establishment, while low temperature restrained seed germination. Both high and low temperatures showed detrimental effects on seedling growth as revealed by reduced establishment percentage, seedling vigor index, and fresh weight due to accumulated reactive oxygens. The antioxidant enzymes responded to high and low temperature differently. Under high temperature, superoxide dismutase (SOD) and peroxidase (POD) activities reduced, while catalase (CAT) activities increased. Under low temperature, however, SOD activities increased, while POD activities reduced, with CAT activities unchanged. Proline played an important role in temperature stress tolerance and can be used as an indicator for tolerance to unfavorable temperature conditions in canola seedlings. Huayouza 9 showed much stronger tolerance to both high and low temperature compared with other cultivars tested in this study. The full extent of tolerance mechanisms need to be further studied.
African swine fever is an acute, febrile and highly virulent porcine disease causing serious economic losses worldwide. The pK205R protein of the African swine fever virus (ASFV) is largely expressed in the early stages of infection, which has given the K205R gene extensive attention. In this study, the ASFV K205R was cloned and expressed in Escherichia coli BL21 (DE3). Expression of histidine-tagged pK205R with a molecular mass of 44 kDa was determined by 12% sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot analysis. Optimisation of culture conditions allowed induction of the recombinant protein with 0.4 mM Isopropyl β-D-thiogalactoside (IPTG) at 37oC for 2 h. The protein existed in cellular supernatant and was purified using a Ni-NTA resin column. The purified protein was used to immunize rabbits four times to enable the production of polyclonal antibodies, and the antiserum titre was detected by ELISA. The results showed that the purified pK205R can react with ASFV positive serum specifically by Western blotting. The pK205R had high antigenicity, which indicated that pK205R could be used as an antigen for detection of ASFV-specific antibodies in ELISA testing, and the recombinant protein could contribute to further research of the action and structure of pK205R.
Coal gasification coarse cinder (CGCC) is the main waste in the coal gasification industry, containing low calorific value but high heavy metal residuals. To achieve environmental toxicity stabilization and waste recycling, we developed a manufacturing method of multiple-functional ceramsite from CGCC by pelletizing and sintering. By altering key parameters during the manufacturing process (including CGCC content, sintering temperature, and time), the physical properties and leaching toxicity of ceramsite were evaluated. Sintering temperature was identified with a significantly positive relationship with ceramsite’s compressive strength, whereas CGCC content was negatively correlated with water adsorption. The highest compressive strength (24.00 MPa) and relatively lower water absorption (21.36%) was achieved at 50% CGCC content and 1,150ºC sintering for 30 min. The toxicity tests showed acceptable leaching heavy metals with minimal environmental impact. Considering the energy conservation and the maximal recycling of CGCC, optimal ceramsite manufacturing is suggested as 50% CGCC content and 1,150ºC/10 min sintering temperature/time. Our results indicated that multiple-functional ceramsite manufacturing is a low-cost and environmentally friendly approach for CGCC recycling.
Soil nutrient pattern can be a functional tool for grassland restoration. In order to promote the growth of a specific or group of expected plant species, it is necessary to measure the responses of different species to nutrient – rich patches and detect the differences among them. In this article, we measured aboveground biomass and morphological traits of six species as dry weight, length, surface area, specific root length and diameter of fine roots in response to nitrogen addition patches using ingrowth core method. The six species are Artemisia scoparia, Stipa bungeana, Artemisia sacrorum, Artemisia giraldii, Lespedeza dahurica and Astragalus melilotoides. All are the dominant species in different stages of secondary succession of loess hilly region, China. Twelve individuals of each species were selected to install ingrowth cores. Six of the individuals were used as treatment group, they were treated to install with four cores of no (addition’s control), low, medium and high levels of nitrogen additions. Another six of them were used as species’ control group, the four installed cores around them had no nitrogen addition. The results showed that: 1) After 105 days in situ, for all the six species, summed dry weight, length and surface area measured in the four cores of the treatment group were significantly greater than the corresponding values in species’ control group. In aboveground biomass, however, only A. scoparia in the treatment group had significantly outweighed that in the species’ control group. 2) Irrespective of nitrogen additions levels, significant differences of length, diameter and surface area existed among the six species, which implied that species had their intrinsic species specific morphological traits. 3) In dry weight, length and surface area, the responses of all the six species to nitrogen addition levels were positive, significantly more roots were grew into the cores with higher nitrogen additions; while in specific root length, the responses were negative. 4) Perhaps the six species had a special nitrogen requirement, as interaction effects of species and addition levels in surface area were found significant. 5) The foraging precision of the six species to nutrient-rich patches had positive but insignificant correlation with root system size; there existed a significant positive correlation between the precision and the sensitivity to the designed patchy habiats. 6) Among the six species, A. scoparia, A. sacrorum and S. bungeana have higher sensitivity and precision than L. dahurica and A. melilotoides in terms of foraging the nitrogen addition cores or patches. It seems that fast growing species that dominate in early successional stage, like A. scoparia and S. bungeana in our case, obtained more benefits from nutrient patchy habitat. We advised that, in infertile lands, fertiliser be applied in a patchy way to accelerate the restoration of old fields as early as possible once they were abandoned.
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