Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 10

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
Protein expressions of Chinese onion accessions grown under monoculture and intercropped with cucumber were evaluated in pot experiments. Chinese onion accessions used were L04 (with weak allelopathic potential) and L06 (with strong allelopathic potential). Root proteins were separated by two-dimensional electrophoresis and the variable expressed protein spots were identified with MALDI-TOFTOF mass spectrometer. Forty-seven identified proteins were classified into nine functional categories. Compared monocropping and intercropping, 31 identified variable protein spots were classified into energy metabolism (14 %), phenylpropanoid biosynthesis (28 %), organosulfur compounds biosynthesis (25 %), carbohydrate metabolism (10 %), fatty acid hydrogen peroxide metabolism (9 %), protein translation (3 %), other function (3 %), and no assigned function (9 %). Compared Chinese onion accessions of differing allelopathy potentials, 22 identified variable protein spots were classified into energy metabolism (18 %), phenylpropanoid biosynthesis (27 %), organosulfur compounds biosynthesis (23 %), carbohydrate metabolism (9 %), nucleosome component (4 %), other function (14 %), and no assigned function (5 %). The level of variable-expressed proteins involved in phenylpropanoid and organosulfur compounds biosynthesis significantly upregulated in treatments intercropped with cucumber. These results suggested that putative allelochemicals of Chinese onion were mainly produced by phenylpropanoid biosynthesis and organosulfur compounds biosynthesis pathway.
The frequently changed temperature could have great effects on soil fauna community during soil thawing period in cold areas. Therefore, soil faunas were investigated in both the soil organic layer (OL) and mineral soil layer (ML) in the primary fir (Abies faxoniana) forest (PF), fir and birch (Betula albosinensis) mixed forest (MF) and secondary fir forest (SF) in the eastern Qinghai–Tibet Plateau every ten days between March 5 and April 25, 2009. Soil macrofauna was picked up by hand in the fields. Mesofauna was collected and separated from the soil samples by Baermann and Tullgren methods, respectively. The dominated species of macrofauna belongedto Coleoptera and Diptera at the early stage of soil thawing, and to Coleoptera, Diptera, Araneae and Hymenoptera at the later stage. However, the dominated species of mesofauna belonged to Nematode, Collembola, and Acari in the whole soil thawing. The density, number of taxa, and diversity index of soil fauna showed significant change with temperature fluctuations and reached an obvious peak when soil temperatures rising above 0°C. The density and number of taxa of macrofauna in both the OL and ML were the lowest on March 5 in the three forests, but the density of mesofauna in both the OL and ML was the highest on March 25, except for the ML in the PF. These results implied that soil fauna community was sensitive to temperature fluctuations, which is important in understanding the ecological processes in the winter–spring transitional period.
Screening and breeding of pollution-safe cultivars (PSCs) has become one of the most direct and cost-effective methods for reducing the health risks of heavy metal-contaminated soil. In this paper we identified and screened out cadmium (Cd)-pollution-safe pakchoi cultivars from 30 pakchoi genetype materials through preliminary screening experiments and re-screening experiments in field conditions. We found that in preliminary screening experiments, the Cd uptake displayed significant variability among the 30 selected pakchoi cultivaters grown in soil with a Cd concentration of 0.51 mg/kg. 11 out of the 30 pakchoi cultivars belonged to the low-Cd accumulated cluster classified by cluster analysis, which had the potential to be Cd-PSCs. The re-screening experiments under different Cd levels of contaminated soils in combination with the studies of the enrichment factors (EFs) and translocation factors (TFs) further confirmed the consistency and genotypic stability of the low-Cd accumulating traits of the potential Cd-PSCs. This study proves the feasibility of applying cluster analysis in the process of identifying PSCs.
To predict the feasibility of whether China can achieve an up to 65% of carbon emissions intensity (CEI) reduction goal from 2005 levels by 2030, we performed dynamic simulations and predictions of China’s CO₂ emissions at the national scale from a system dynamics perspective. More specifically, we developed a system dynamics model based on LMDI analysis to simulate and estimate CO₂ emissions under 10 different scenarios in China during 1991-2030. The result shows that China’s CEI will decrease by 67.86-84.63% in 2030 compared to the 2005 level, which means that China will be able to meet the emission reduction goal by 2030, and China’s CO₂ emissions will peak sometime between 2020 and 2025. In addition, the quantitative evidence suggests that transforming the energy structure will make a significant contribution to CO₂ emissions reduction. As the proportion of renewables increases, CO₂ emissions decrease in terms of both scale and peak value and peaks earlier. So, the findings also indicate that the optimization for energy structure by replacing fossil fuels (especially coal) with renewables at a suitable growth rate can promote the coordination between economic growth and CO₂ emissions mitigation.
Soil salinity is one of the major abiotic stresses affecting crop growth and yield worldwide. Barley is a species with higher salt tolerance among cereal plants and rich in genetic variation. It is quite important to understand the physiological mechanisms of genotypic difference in salt tolerance. In this study, physiological and biochemical responses of a Tibetan wild barley genotype XZ16 (salt tolerant) and a cultivated cultivar Yerong (salt sensitive) to salt stress were investigated. The results showed that the two genotypes differed dramatically in their responses to salt stress (150 and 300 mM NaCl) in terms of plant biomass, Na+ accumulation and Na+/K+ ratio in roots and shoots, chlorophyll content, xylem sap osmolarity and electrolyte leakage. XZ16 showed less biomass reduction, lower Na+/K+ ratio and electrolyte leakage, higher xylem sap osmolarity, and vacuolar H+-ATPase and H+-PPase activities than Yerong under 300 mM NaCl. The higher salt tolerance of XZ16 may be attributed to its lower concentration of Na+ influx or more sequestration into the vacuoles. The results indicate that the Tibetan wild barley is useful for improvement of cultivated barley in salt stress tolerance.
Background: The transcription factor Oct4 plays a pivotal role in the preimplantation development of the mouse embryo. DNA methyltransferase 1 (Dnmt1) maintains the changes in DNA methylation during mammalian early embryonic development. Little is known of the role of Oct4 in DNA methylation in mice. In this study, Kunming white mice were used as an animal model to reveal any correlation between DNA methylation and Oct4 during mammalian embryonic development. Results: The expressions of Dnmt1 and Oct4 were initially studied using real-time PCR. They exhibited different patterns during the pre-implantation stage. Moreover, by using a promoter assay and ChIP analysis, we found that the transcriptional activities of Dnmt1 in mouse NIH/3 T3 cells and CCE cells were regulated by Oct4 through direct binding to the − 554 to − 294 fragment of the upstream regulation element of Dnmt1. The downregulation of Dnmt1 expression and enzyme activity by mouse Oct4 were further confirmed by transfecting Oct4 siRNA into mouse CCE cells. Conclusion: Our results indicate that Oct4 is involved in DNA methylation through the regulation of Dnmt1 transcription, especially during the early stages of mouse pre-implantation embryo development.
Decomposition of litter is a crucial process in terrestrial ecosystems, determining global carbon budget and nutrient turnover. Soil faunas have been shown to accelerate the rates of litter decomposition and nutrient cycling in terrestrial ecosystems. Litter decomposition has recently been observed in winter in alpine/subalpine ecosystems, but the contribution of soil fauna to the decomposition process is not clear. Field experiment using litterbags was conducted in order to quantify the contributions of soil fauna to mass losses of fir (Abies faxoniana) and birch (Betula albosinensis) litters during a freeze-thaw season in three representative alpine/subalpine forests. The litterbags of mesh sizes 0.02 mm, 0.125 mm, 1.0 mm and 3.0 mm were placed on the forest floor in October 2010, and collected after each of the three stages of the freeze-thaw season: OF, the onset of freezing stage (26 October to December 31); DF, the deeply frozen stage (1 January to 4 March 2011); and TS, the thawing stage (5 March to 30 April 2011) over the entire 2010/2011 winter. Over the whole freeze-thaw period, the mass losses of fir litter were 11–12% (0.02 mm), 12–13% (0.125 mm), 14–15% (1.0 mm) and 17–19% (3.0 mm), and that of birch litter were 10–13% (0.02 mm), 12–15% (0.125 mm), 13–18% (1.0 mm) and 17–22% (3.0 mm), respectively, depending on the altitude. The mass losses caused by microfauna, mesofauna and macrofauna for the fir litter accounted for 6–9, 12–13 and 22–25%, respectively and that for the birch litter accounted for 8–11, 13–15 and 25–27%, respectively. Furthermore, the contributions of soil fauna to mass loss showed an increasing trend with increasing body size regardless of species at three stages of the freeze-thaw period. These results suggest that soil fauna contributes strongly to litter decomposition during the freeze-thaw period in alpine/subalpine regions.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.