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Genome-wide gene expression profiling was conducted by Solexa sequencing in order to gain insight into the transcriptome dynamics that are associated with salt stress of cotton seedlings. A total of 145,794 and 138,518 clean tags were generated from the control and salinity libraries, respectively. Of these, 75,500 (51.8%) and 72,077 (52.0%) tags were matched to the reference genes. The most differentially regulated tags with a log2ratio >2 or >-2 (P <0.001) were analyzed further, representing 125 up- and 171 down-regulated genes except for unknown transcripts, which were classified into ten functional categories. The most enriched categories were those of metabolism, signaling pathway, environmental response and transcription. Many genes or biological pathways were found to be commonly shared between salt and other abiotic stresses in plants such as genes participating in environmental response, ABA signaling JA signaling, etc. Furthermore, the expression patterns of 12 genes were assessed by quantitative real-time PCR, and the results obtained showed general agreement with the Solexa data. Further analysis indicated the important roles of selected genes in salt tolerance by comparison with the mRNA levels in salt-tolerant cotton cultivar ZM3 with that in salt-sensitive cultivar LM6. Overall, we reveal the complex changes at the transcriptional level during salt stress of cotton seedlings and provide useful starting points for more in-depth analyses of cotton’s salt tolerance.
Biochar amendment may improve crop growth through its nutrients and indirect fertility. However, this improvement varies in a wide range of biochars, crops, and soils. Our objectives were to determine the response of crop growth to biochar amendment and to assess the N use efficiency relative to the biochar and the soil types. In this pot experiment, we investi-gated five typical agricultural soils in China amended with two biochars. Four treatments were designed: the soil itself as a control, the soil amended with 1% biochar, the soil with fertilizer NPK, and the soil with added biochar and fertilizer. Biochar amendment increased the maize biomass and the N use efficiency in the red soil (p<0.05) but not in the other four soils (p>0.05). In the red soil, the biomass under biochar+NPK was 2.67-3.49 times higher than that of only NPK, and 1.48-1.62 times higher than that of only biochar amendment, 21-36 and 35-42% of which were contributed from biochar fertility and indirect fertility, respectively. This study indicates that biochar amendment is very plausible for the red soil but has a minor or even negative effect on the other four soils in China.
Moisture content uniformity is one of critical parameters to evaluate the quality of dried products and the drying technique. The potential of the hyperspectral imaging technique for evaluating the moisture content uniformity of maize kernels during the drying process was investigated. Predicting models were established using the partial least squares regression method. Two methods, using the prediction value of moisture content to calculate the uniformity (indirect) and predicting the moisture content uniformity directly, were investigated. Better prediction results were achieved using the direct method (with correlation coefficients RP = 0.848 and root-mean-square error of prediction RMSEP = 2.73) than the indirect method (RP = 0.521 and RMSEP = 10.96). The hyperspectral imaging technique showed significant potential in evaluating moisture content uniformity of maize kernels during the drying process.
Recently, the photocatalytic degradation technique with titanium dioxide (TiO₂) has been widely applied for the degradation of humic acid (HA) from aqueous solution due to its ability to achieve complete mineralization of organic contaminants. Because TiO₂ is the most commonly used semiconductor photocatalyst, efforts on the modification of TiO₂ in order to improve catalyst efficiency were presented in this review manuscript. The key photoreactor operation parameters such as TiO₂ loading, pH, temperature, oxygen concentration, concentration and nature of HA, light wavelength, light intensity, the presence of inorganic ions and mechanistic pathway for pollutant removal, and the formation of the intermediates and their effects on the mineralization and disinfection of the photo-process were also assessed. Although we can see an increase in the number of papers that have been published in this area, further progress is needed to improve the understanding of the dynamic interactions between TiO₂ photocatalytic oxidation process and HA, as well as to suggest possible future developments in this promising field.
Shikimate kinase (SK), an indispensable enzyme in shikimate pathway, catalyzes the transfer of a phosphate from Adenosine triphosphate (ATP) to 3-hydroxyl of shikimate to form shikimate 3-phosphate. There are many active metabolites from shikimate pathway in Cassia obtusifolia. A new member of SKs from C. obtusifolia named CoSK was cloned and subjected to in silico characterization analysis. The constructed 3D structure of CoSK adopted α-β-α fold with five parallel β-sheets flanked by 12 α-helices. CoSK was shown to possess the potential ability to catalyze the phosphorylation of shikimate. Residues Lys118 and Arg223 binding with ATP and residue Asp137 binding with shikimate might be essential for phosphorylating shikimate. These results will provide useful information concerning the catalytic and physiology mechanism of SK in plants.
The regional carbon budget of the climatic transition zone may be very sensitive to climate change and increasing atmospheric CO2 concentrations. This study simulated the carbon cycles under these changes using process-based ecosystem models. The Integrated Biosphere Simulator (IBIS), a Dynamic Global Vegetation Model (DGVM), was used to evaluate the impacts of climate change and CO2 fertilization on net primary production (NPP), net ecosystem production (NEP), and the vegetation structure of terrestrial ecosystems in Zhejiang province (area 101,800 km2, mainly covered by subtropical evergreen forest and warm-temperate evergreen broadleaf forest) which is located in the subtropical climate area of China. Two general circulation models (HADCM3 and CGCM3) representing four IPCC climate change scenarios (HC3AA, HC3GG, CGCM-sresa2, and CGCM-sresb1) were used as climate inputs for IBIS. Results show that simulated historical biomass and NPP are consistent with field and other modelled data, which makes the analysis of future carbon budget reliable. The results indicate that NPP over the entire Zhejiang province was about 55 Mt C yr-1 during the last half of the 21st century. An NPP increase of about 24 Mt C by the end of the 21st century was estimated with the combined effects of increasing CO2 and climate change. A slight NPP increase of about 5 Mt C was estimated under the climate change alone scenario. Forests in Zhejiang are currently acting as a carbon sink with an average NEP of about 2.5 Mt C yr–1. NEP will increase to about 5 Mt C yr–1 by the end of the 21st century with the increasing atmospheric CO2 concentration and climate change. However, climate change alone will reduce the forest carbon sequestration of Zhejiang’s forests. Future climate warming will substantially change the vegetation cover types; warm-temperate evergreen broadleaf forest will be gradually substituted by subtropical evergreen forest. An increasing CO2 concentration will have little contribution to vegetation changes. Simulated NPP shows geographic patterns consistent with temperature to a certain extent, and precipitation is not the limiting factor for forest NPP in the subtropical climate conditions. There is no close relationship between the spatial pattern of NEP and climate condition.
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