Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 22

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 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 / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
1

Effects of nutrient availability and competition between two grass species Leymus chinensis [Trin.] Tzvel. and Phragmites communis Trin. on the plant performance

100%
Ba L., Xiao N., Xu W., Wang D.
Polish Journal of Ecology
|
2008
|
tom 56
|
nr 3
453-462
Leymus chinensis (Trin.) Tzvel., a perennial grass, is a dominant species from arid to semi-arid steppes in northern China and eastern Mongolia. Phragmites communis Trin. is also a perennial grass, and is distributed widely in the world. In the natural grasslands of northeastern China, both species always co-exist as co-dominating species due to their common characteristics such as propagation both by seeds and vegetative reproduction. Replacement series experiments were used to test the effects of nutrient availability and competitive interaction on the growth performance of two clonal plant species. The experimental treatments included five nutrient levels (3.6, 7.2, 10.8, 14.4 and 18.0 kg organic matter per pot, 20 cm diameter and 15 cm deep) and five species proportions (20:0, 16:4, 10:10, 4:16 and 0:20 for L. chinensis and P. communis, respectively) with twenty tillers in total per pot. Each treatment had 10 replications. Growth characteristics including tiller height, tiller number, plant biomass, rhizome length and bud number of plants in monoculture and mixture culture were recorded and compared to examine the effects of nutrient and competitive interaction on the plant performance. The growth of L. chinensis and P. communis in mixture was influenced by the nutrient availability and competition, which depended on the combination between nutrient level and species proportion. The results implied that the intensity of competition should be lower in nutrient-poor habitats when the co-existing species demanded on the same limiting resource. P. communis benefited from coexisting with L. chinensis, especially under nutrient-rich conditions. The aboveground relative yield (RYabove) expressed in units of tiller height, dry biomass and daughter tiller number was recommended as an effective and simple index to predict the relative competitive ability for clonal plants. It was based on the regression for RY above and RYbelow (the belowground relative yield) against RY (relative yield), measured as yield in mixture divided by that in monoculture.
2

Habitat effects on leaf morphological plasticity in Quercus acutissima

100%
Xu F., Guo W., Xu W., Wang R.
Acta Biologica Cracoviensia. Series Botanica
|
2008
|
tom 50
|
nr 2
19-26
Phenotypic plasticity acts to increase the performance of plants under stress. Leaf morphological plasticity and its causes in different environments are incompletely understood. We measured the leaf morphological parameters of Quercus acutissima Carr. seedlings, including leaf size, leaf shape and venation pattern, assessing the effects of different habitat conditions on leaf morphological plasticity. A field study in forest edge and understory was combined with experiments simulating different light and water conditions. Leaf morphology variations occurred over most of the parameters, and the causes were consistent between the field study and lab experiment. Leaf size decreased with low supply of light and water. Leaf length and width were only affected by leaf area. The leaf petiole did not lengthen under shade stress, suggesting a trade-off relationship between functional tissues and support structures. Leaf shape became narrower in drought and broader in the shade, as reflected in changes in three leaf fractions. Higher vein density played a part in enhancement of mechanical support and water supply. Leaves with more teeth show more active photosynthesis, but are disadvantageous in xeric environments because of higher transpiration. Light was the main factor inducing leaf morphological plasticity. The variations caused by drought were due mainly to the allometry. Our results showed that the leaves of Q. acutissima seedlings respond to different habitats with phenotypic plasticity of morphology, suggesting that this is an important mechanism for seedlings to adapt to broader ecological amplitudes.
3

Long non-coding RNA LINC00662 promotes proliferation and migration of breast cancer cells via regulating the miR-497-5p/EglN2 axis

100%
Cheng L., Xing Z., Zhang P., Xu W.
Acta Biochimica Polonica
|
2020
|
tom 67
|
nr 2
4

Reconstruction of wetland zones: physiological and biochemical responses of Salix variegata to winter submergence — a case study from water level fluctuation zone of the Three Gorges Reservoir

100%
Miao L., Xiao F., Xu W., Yang F.
Polish Journal of Ecology
|
2016
|
tom 64
|
nr 1
The Salix variegata Franch. seedlings planted in the Three Gorges Reservoir (TGR) water level fluctuation zone (WLFZ) could survive after experiencing several seasons of winter submergence. We investigated the recovery mechanisms of S. variegata seedlings planted at the elevation of 168 m and 172 m in the TGR WLFZ after winter submergence. The results indicated that winter submergence caused some impacts on S. variegata seedlings with increases of hydrogen peroxide (H₂O₂), superoxide anions radical (O₂⁻˙), and malondialdehyde (MDA) levels, and decreases of antioxidant enzymatic systems during recovery stage after winter submergence. However, further analyses of relative water content (RWC), pigment content, proline content, carbohydrate content and several other antioxidant enzymatic activities (catalase (CAT), guaiacol peroxidase (G-POD), and glutathione peroxidase (GSH-POD)) showed that S. variegata seedlings were well recovered after winter submergence. These results indicate that S. variegata possesses strong winter submergence tolerance and adaptation to the specific hydrological environment in the TGR WLFZ. Therefore, S. variegata should be popularized as native tree species during the revegetation in the TGR WLFZ.
5

Plant regeneration of the arsenic hyperaccumulator Pteris vittata L. from spores and identification of its tolerance and accumulation of arsenic and copper

100%
Zheng Y., Xu W., He Z., Ma M.
Acta Physiologiae Plantarum
|
2008
|
tom 30
|
nr 2
An in vitro plant regeneration system was established from the spores of Pteris vittata and identification of its tolerance, and accumulation of gametophytes and callous, to arsenic (As) and copper (Cu) was investigated. The highest frequency (100%) of callus formation was achieved from gametophyte explants treated with 0.5 mg l⁻¹ 6-benzylaminopurine (6-BA) + 0.5 mg l⁻¹ gibberellin acid (GA). Furthermore, sporophytes were differentiated from the callus tissue derived from gametophyte explants on MS medium supplemented with 0.5 mg l⁻¹ 6-BA, 0.5–1.0 mg l⁻¹ GA and additional 300 mg l⁻¹ lactalbumin hydrolysate (LH) for 4 weeks. The optimum combination of ½ MS + 1.0 mg l⁻¹ GA + 0.5 mg l⁻¹ 6-BA + 300 mg l⁻¹ LH promoted sporophyte formation on 75 ± 10% of the callus. Every callus derived from gametophyte explants could achieve 3–4 sporophytes. The in vitro growth of gametophyte and callus was accelerated in the medium containing Na3AsO4 lower than 0.5 mM, but this growth was inhibited with 2 mM Na3AsO4. And with the increase of Na3AsO4 in the culture medium from 0 to 2 mM, the As accumulation in gametophytes and callus increased and achieved a level of 763.3 and 315.4 mg kg⁻¹, respectively. Gametophytes and calluses transplanted to culture medium, supplemented with different concentrations of CuSO4, are similar to those in Na3AsO4, and the Cu accumulation in gametophytes could achieve 7,940 mg kg–1 when gametophytes were subcultured in medium containing 3 mM CuSO4. These results suggested that the high efficiency propagation system could be a useful and rapid means to identify other heavy metal tolerance and accumulation. Further, the regeneration ability of callus made it possible for genetic transformation of this fern.
6

Drought tolerance of nitric oxide associated 1 mutant of Arabidopsis is mostly due to its reduced transpiration as a result of smaller stature

100%
Xu W., Zhang S., Wang D.-L., Liu J.-Z.
Acta Physiologiae Plantarum
|
2015
|
tom 37
|
nr 07
Arabidopsis noa1 mutant has a small stature and is more resistant to water deficit than wild-type Col-0. To investigate whether the size of noa1 plays a role in drought tolerance, Col-0, noa1 as well as gsnor1-3 and a transgenic line over-expressing a DnaJ domain Hsp40 from soybean (GmHSP40ox), all of which have smaller statures than Col-0, were subjected to drought treatment. Our results showed that the genotypes with smaller statures survived longer than Col-0 under drought conditions when grown in separate containers, which is correlated with the reduced net water losses of plants and the higher water content in the soil during the drought stress treatment. However, when randomly grown in the same containers, the plants of the four genotypes dried out almost at the same time, indicating that the reduced transpirations due to the smaller sizes of the mutant plants might account for the prolonged surviving under drought in separate containers. In the same-container experiment, the accelerated water loss caused by the transpiration of Col-0 plants most likely contributed to the earlier dry-out of the three genotypes with smaller statures because a certain amount of the transpired water through Col-0 could have been used by noa1 gsnor1-3 or GmHSP40ox if grown in separate pots. Interestingly, noa1 had less stomata densities and the stomatal closures of both noa1 and gsnor1-3 were more sensitive to ABA. In addition, noa1 was more resistant to osmotic stress than both Col-0 and gsnor1-3. To our surprise, the water loss rates of detached leaves of both noa1 and gsnor1-3 were greater than that of Col-0, suggesting that the water loss rates of detached leaves may not represent that of in planta leaves. Together, our results suggest that (1) plant sizes of different genotypes must be taken into consideration in evaluating drought trait, and multiple approaches and criteria are needed to ensure the accurate evaluation of drought tolerance; (2) when investigated genotypes have big differences in statures, both the samecontainer and the separate-container experiments are necessary for screening the resistant or tolerant genotypes; when the investigated genotypes have comparable statures, the separate-container experiment is more relevant; (3) the increased drought tolerance of noa1 is resulted from combined effects of the smaller stature, the increased sensitivity of stomata closure to ABA and the enhanced resistance to osmotic stress; and (4) water loss rate of detached leaves is not a good indicator in evaluating drought tolerance.
7

The feasibility of AOPs and an SBR for treating wastewater from polyurethane manufacturing

88%
Li A., He M., Dong N., Xu W., Pan T.
Polish Journal of Environmental Studies
|
2014
|
tom 23
|
nr 4
We studied the feasibility of two advanced oxidation processes (AOPs), including the Fenton and ozonation processes, and a conventional sequence batch reactor (SBR) for treating wastewater from polyurethane manufacturing. The results showed that the SBR achieved a COD removal rate of 93.3% when the influent COD concentration was 1,600 mg·L-1, which was 22.1 and 522.1% higher than the best results by the Fenton (H2O2/COD = 0.0623 mM·g-1 and Fe2+/COD = 0.0102 mM·g-1) and ozonation (1 g·L-1, 45 min) processes. A COD removal rate of 90.6% for SBR was achieved after an aeration time of 12 h, and the COD degradation rate was similar to that of a zero-order reaction. A study of the SBR drivers suggested that air stripping and self-volatilization contributed to the higher COD removal rates obtained in this process. This study shows that a single SBR is practical for treating small amounts of polyurethane manufacturing wastewater, and that it had a higher ability to remove COD and resist feeding load shock than the other methods tested. But the potential risks of volatile organic compounds (VOCs) stripping out during the aeration process should be of concern.
8

Effects of forest on mean annual runoff in north china

88%
Wang H., Xu W., Zhang M., Cui L., Yu X.
Polish Journal of Environmental Studies
|
2018
|
tom 27
|
nr 2
The forest-water relationship is a hot and important issue in ecohydrology studies. China has implemented many large-scale reforestation programs in the past decades to address growing soil erosion and desertification, but that also caused serious water yield reductions. In this study, based on the simple water balance equation, we made statistical and graphic analyses on the long-term hydrological data of the 42 watersheds in the rocky mountain area of northern China, and then we were able to analyze the impact trend of forest on water yield. Our results show that the impact of forest on runoff is very weak in the lower-precipitation regions (in this study <500 mm). In the higher-precipitation regions (>500 mm) the impact of forest on reducing water yield is different with the increasing forest coverage (f), and runoff shows an impact trend of “weak-big-severe”; the largest absolute MAR is about 225 mm, and the largest MAR ratio is about 35%. We highlight the importance of dividing different forest-coverage phases in analyzing the effect of a forest on water yield.
9

Analysis of the start-up of natural bio-film colonization of constructed rapid infiltration system

88%
Xu W., Yang J., Wang J., Jian Y., Tang M.
Polish Maritime Research
|
2016
|
tom 23
|
nr Special Issue S1
Abstract: this paper studied the start-up of natural bio-film colonization under the conditions where wet-to-dry ratio was 1:6, hydraulic load was 0.8m3/m2·d, and water temperature was 100C-150C, it took 25d in total to become mature, after the success of bio-film colonization, the removal rate of COD and NH4+-N can be stabilized at 80%, and the removal rate of NH4+-N can reach 90% above. The microorganism was divided into the following stages during bio-film colonization:1. Reversible adhesion of cell on the surface of the carrier, 2.Irreversible adhesion of cell on the surface of the carrier, 3.Division of cell adhering to the surface of the carrier and formation of microcolony adhering to the surface of the carrier, 4.Growth of microcolony adhering to the surface of the carrier to be mature bio-film with three-dimensional structure. The process of natural bio-film colonization can be judged comprehensively according to removal rate of NH4+-N and COD, effluent pH as well as color of microbial film
10

River health evaluation based on the fuzzy matter-element extension assessment model

88%
Xu W., Dong Z., Hao Z., Li D., Ren L.
Polish Journal of Environmental Studies
|
2017
|
tom 26
|
nr 3
The measured values of river health indexes that are not necessarily in the same range of a certain health grade level cause the problem of how to classify the actual status of river health. To solve such incompatibility and evaluate the health condition of a river ecosystem objectively we can use the river health integrated index (RHI), which was determined by the fuzzy matter-element extension assessment model (FMEAM). FMEAM was established by combining the fuzzy matter-element extension assessment method with the proposed aggregative index system. By employing the model above, as well as data from the 1980s, 1990s, and 2000s, we evaluated the health state of the Luanhe River. The results showed that the Luanhe River was in a sub-healthy state in the 1980s and in an unhealthy state in the 1990s and 2000s. The reasons leading to the Luanhe River’s health degradation have been analyzed. Among them, water conservation projects’ building and operations are the major influence factors. Waste water emissions, the expansion of urban built-up areas, over exploitation of groundwater, and other unreasonable human activities also intensified the river ecosystem degradation. Finally, countermeasures for the ecological restoration and protection of the river were put forward.
11

Optimizing the DRASTIC Method for nitrate pollution in groundwater vulnerability assessments: a case study in China

88%
He H., Li X., Cui J., Zhang W., Xu W.
Polish Journal of Environmental Studies
|
2018
|
tom 27
|
nr 1
Groundwater vulnerability assessments, using DRASTIC, are important and useful tools for groundwater pollution prevention and control. The DRASTIC method, however, is not appropriate for accurate specific vulnerability assessments where nitrate concentrations are high. A new method has been developed that retains the basic structure of DRASTIC while adding or subtracting parameters, and modifying the parameter ratings and weightings. The resulting DRACILM model was used to assess vulnerability to nitrate pollution in the West Liaohe Plain and as a basis for vulnerability mapping. The accuracy, appropriateness, and reliability of the vulnerability mapping were analyzed using a group of integrated indicators, such as correlation, ANOVA F-statistics, and single-parameter sensitivity analysis. The correlation between vulnerability class and the concentration of NO₃-N in the DRACILM model improved to 0.649, which was 40.6% higher than that obtained by DRASTIC. The ANOVA F-statistic was 27.71, which indicated a lower overlap between the mean values of nitrates in the different vulnerability classes. The single-parameter sensitivity analysis revealed that land use type exhibited the highest and hydraulic conductivity the lowest effective weighting values. The vulnerability maps by DRACILM model could assist planners and government decision-makers with preliminary investigations into planning water protection projects or establishing management scenarios for water resource quality.
12

The future prospects of arbuscular mycorrhizal fungi in slope ecological restoration

76%
Yan Y., Zhao B., Xu W., Yu F., Liu W., Xia D.
Polish Journal of Environmental Studies
|
2020
|
tom 29
|
nr 3
13

Initial start-up characteristics of anaerobic ammonium oxidation in a UASB reactor

76%
Cheng H., Yan Y., Yi X., Wang J., Xu W., Nie H.
Polish Journal of Environmental Studies
|
2020
|
tom 29
|
nr 3
14

Drought stress condition increases root to shoot ratio via alteration of carbohydrate partitioning and enzymatic activity in rice seedlings

76%
Xu W., Cui K., Xu A., Nie L., Huang J., Peng S.
Acta Physiologiae Plantarum
|
2015
|
tom 37
|
nr 02
To understand the underlying mechanism for plasticity in root to shoot ratio (R/S) in response to drought stress, two rice cultivars, Zhenshan97 (drought susceptible) and IRAT109 (drought resistant), were grown hydroponically, and R/S, carbohydrate concentration and partitioning, and activities of enzymes for sucrose conversion in seedlings exposed to drought stress condition (DS) imposed by polyethylene glycol 6000 were investigated. The R/S significantly increased under DS in comparison with that under well-watered condition. The proportion of dry matter and soluble sugar of roots markedly increased under DS. The R/S was negatively correlated with proportion of soluble sugar in stems, and positively with the proportions of soluble sugar and starch in roots. Drought stress condition significantly increased leaf sucrose-phosphate synthase (EC 2.4.1.14) activity and root acid and neutral/ alkaline invertase (EC 3.2.1.26) activity. The R/S was positively correlated with leaf sucrose-phosphate synthase and root acid invertase activity, and negatively with leaf sucrose synthase activity in the cleavage direction. Our results indicate that the increase in R/S in response to DS is closely associated with the higher proportion of dry matter and soluble sugar in roots, and this occurs via an increase in leaf sucrose-phosphate synthase and root invertase activity, and thus more sucrose is available for transport from leaves to roots.
15

Study on runoff evaluation law in the Luanhe River Basin, China

76%
Shan C., Dong Z., Huang D., Lu Y., Xu W., Zhang Y.
Polish Journal of Environmental Studies
|
2021
|
tom 30
|
nr 1
16

Leaf movement and photosynthetic plasticity of black lokust (Robinia pseudoacacia) alleviate stress under different light and water conditions

76%
Xu F., Guo W., Wang R., Xu W., Du N., Wang Y.
Acta Physiologiae Plantarum
|
2009
|
tom 31
|
nr 3
Leaf morphological, physiological and biochemical characteristics of Robinia pseudoacacia L. seedlings were studied under different stress conditions. The plants were subjected to drought and shade stress for one month. Leaf inclination, chlorophyll fluorescence and chlorophyll content were measured at the first day (shortterm stress) and at the end of the stress period (long-term stress) and in the recovery period. Leaf inclination was affected mainly by light; a low level of irradiance caused leaves to be arranged horizontally. Diurnal rhythmicity was lost after the long-term stress, but resumed, in part, in the recovery period. Drought stress caused leaves to tilt more obviously and decreased damage to the photosystem. Sun avoiding movement in a single leaf and sun tracking movement in the whole plant coexisted. Significant physiological changes occurred under different conditions of light. Increased energy dissipation and light capture were the main responses to high and low level of irradiance, respectively, and these were reflected by changes of chlorophyll fluorescence and chlorophyll content. Phenotypic plasticity in the leaflet enhanced the protective response to stress. These adaptive mechanisms may explain better survival of R. pseudoacacia seedlings in the understory, especially during the drought periods, and made it to be the preponderant reforestation species in Shandong Province of China.
17

Performance and microbial community analysis of a constructed rapid infiltration system at different depths

76%
Cheng H., Xia G., Li M., Qian L., Xu W., Liu Y.
Polish Journal of Environmental Studies
|
2020
|
tom 29
|
nr 5
18

Highly selective copper and nickel separation and recovery from electroplating sludge in light industry

76%
Xu W., Liu W., Zhu H., Xu J., Li G., Fu D., Luo L.
Polish Journal of Environmental Studies
|
2015
|
tom 24
|
nr 1
Electroplating sludge and associated waste products comprise complex mixtures of metallic elements and may cause serious environmental pollution if discharged without treatment. An effective light industrial process is modified to selectively extract and recover copper and nickel from electroplating sludge. The procedure was developed on a laboratory scale and validated in a small pilot plant. Extraction yields of greater than 95% for Cu and Ni are achieved under optimum leaching conditions. To selectively recover copper and nickel from the leaching solution, they were extracted by N902 in kerosene, followed by selective stripping using sulfuric acid. The overall recoveries of copper and nickel were 93.6% and 88.9%, respectively, via a fast, simple, and inexpensive process. Partial recovery of ammonia in the process enables some cost savings. The technology can be used for metal resource recovery from solid wastes containing copper and nickel.
19

Sirtuin inhibition increases the rate of non-homologous end-joining of DNA double strands breaks

76%
Wojewodzka M., Kruszewski M., Buraczewska I., Xu W., Massuda E., Zhang J., Szumiel I.
Acta Biochimica Polonica
|
2007
|
tom 54
|
nr 1
Sirtuins (type III histone deacetylases) are an important member of a group of enzymes that modify chromatin conformation. We investigated the role of sirtuin inhibitor, GPI 19015, in double strand break (DSB) repair in CHO-K1 wt and xrs-6 mutant cells. The latter is defective in DNA-dependent protein kinase (DNA-PK)-mediated non-homologous end-joining (D-NHEJ). DSB were estimated by the neutral comet assay and histone γH2AX foci formation. We observed a weaker effect of GPI 19015 treatment on the repair kinetics in CHO wt cells than in xrs6. In the latter cells the increase in DNA repair rate was most pronounced in G1 phase and practically absent in S and G2 cell cycle phases. The decrease in the number of histone γH2AX foci was faster in xrs6 than in CHO-K1 cells. The altered repair rate did not affect survival of X-irradiated cells. Since in G1 xrs6 cells DNA-PK-dependent non-homologous end-joining, D-NHEJ, does not operate, these results indicate that inhibition of sirtuins modulates DNA-PK-independent (backup) non-homologous end-joining, B-NHEJ, to a greater extent than the other DSB repair system, D-NHEJ.
20
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

Magnolol inhibits Streptococcus suis-induced inflammation and ROS formation via TLR2/MAPK/NF-κB signaling in RAW264.7 cells

64%
Zhang L., Wang J., Xu W., Sun Y., You J., Lu H., Song Y., Wei J., Li L.
Polish Journal of Veterinary Sciences
|
2018
|
tom 21
|
nr 1
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 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.