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Objective: To observe the expression of Wnt5a/c-Jun N-terminal kinase (JNK) signaling pathway in the lung of asthmatic rats., Methods: The experimental rats were randomly divided into two groups, the model group and the control group. After the rat models of asthma were established, airway pathological changes were observed by HE staining; the expression of Wnt5a mRNA in the lung tissues and peripheral blood cells was examined by real-time quantitative PCR; and the levels of phospho-c-Jun (p-c-Jun) and phospho-c-Jun N-terminal kinase (p-JNK) proteins in the lung tissues were measured by Western blotting., Results: Compared with the control group, asthmatic rats presented with thickened bronchial mucosa with more obvious chrysanthemum fold, narrower airway, and more inflammatory cells infiltrated around trachea and pulmonary vessels. The inner airway wall and smooth muscle layer were much thicker in rats of asthma group than those of control group. The levels of Wnt5a mRNA, p-c-Jun and p-JNK proteins in the lung and blood of asthmatic rats increased as compared with the control group., Conclusion: The expressions of Wnt5a mRNA, p-JNK and p-c-Jun proteins were elevated in asthmatic rats.

Objective: To investigate whether immune response could change the number of CD4(+);IL-17(+);Th17 cells and the concentrations of IL-17 and IL-23 in the serum and lymph of asthmatic rats., Methods: Both serum and lymph CD4(+);IL-17(+);Th17 cell numbers were measured by flow cytometry. The concentrations of IL-17 and IL-23 in the serum and lymph were assayed by ELISA. The expression of IL-23 p19 mRNA was examined by quantitative real-time PCR., Results: Mononuclear cells (MNC) were collected from the blood and lymph of rats 0, 24 and 48 hours after final ovalbumin stimulation and were subsequently cultured for 18 hours. The serum and lymph of the asthma group produced higher amounts of CD4(+);IL-17(+);Th17 cells, and higher levels of IL-23p19 mRNA, than those of the healthy controls (P < 0.05). In addition, compared to lymph, serum had significantly lower amounts of CD4(+);IL-17(+);Th17 cells, decreased expression of IL-23p19 mRNA, and reduced IL-23 and IL-17 concentratons (P < 0.05). Cytokines and cell numbers of Th17 cells from the asthma group significantly increased compared with that of control group., Conclusion: These data suggested that asthma-driven CD4(+);IL-17(+);Th17-cell proliferation and release of IL-17 and IL-23 may be associated with different immune activities between the serum and lymph.

In this paper, the respiration rates of soil, foliage, and stem and branch in the broadleaved Korean pine forest ecosystem of Changbai Mountains were measured by Li-6400 CO2 analysis system in 2003, with the microclimate factors determined synchronously. The correlation models of ecosystem respiration with environmental factors were established, and the respiration rate of each component of the ecosystem was estimated based on the vegetation characteristics of the broadleaved Korean pine forest. The results showed that the annual total respiration rate of the ecosystem was 1602. 8 g C x m(-2), with a mean of (4. 37+/-2. 98) micromol x m(-2) x s(-1) , and the respiration of soil, foliage, and stem and branch contributed about 63% , 21% , and 16% of the total, respectively. There was a significant correlation between system respiration and daily mean air and soil temperature, and about 87% and 95% of the ecosystem respiration could be explained by the air and soil temperature, respectively.

By the method of static opaque chamber/modified gas chromatography, a one-year field experiment was conducted to measure in situ the CH4 and N2O emission from a winter-time flooded paddy field in a hilly area of Southwest China. Gas samples were taken simultaneously from rice-involved and rice-uninvolved plots. The results showed that during rice growth period, the CH4 emission from the winter-time flooded paddy field was higher than that from other paddy fields, but largely lower than many previous reports for the similar regions in Southwest China. The average flux of CH4 emission from rice-involved plots was 22.76 +/- 2.76 mg CH4 x m(-2) x h(-1) during rice growth period, 9.64 +/- 1.17 mg CH4 x m(-2) x h(-1) per year, and 1.43 +/- 0.20 mg CH4 x m(-2) x h(-1) during non-rice growth season; while that from rice-uninvolved plots was only 2.03 +/- 0.18 mg CH4 x m(-2) x h(-1) per year, markedly lower than those from rice-involved plots. During rice growth season, the mean emission rate of CH4 and N2O was 4.53 +/- 0.38 mg CH4 x m(-2) x h(-1) and 32.01 +/- 5.02 microg N2O x m(-2) x h(-1) from rice-uninvolved plots, but reached to 22.76 +/- 2.76 mg CH4 x m(-2) x h(-1) and 73.04 +/- 5.03 microg N2O x m(-2) x h(-1) from rice-involved plots, respectively. Rice involvement resulted in 302% increment of CH4 and 128% increment of N2O emission. There was a clear trade-off between CH4 and N2O emission in paddy fields. Even with a span of 500 years, our calculation showed that in this winter-time flooded paddy field, the GWP contributed by N2O production was 7.9% of the CH4 contribution, and thus, the greenhouse effect of N2O production from this field was very small.

The soil N2O and CH4 fluxes in the broad-leaved Korean pine forest of Changbai Mountains under two treatments were measured by static chamber-gas chromatograph. The results showed that litter significantly influenced N2O emission and CH4 uptake, and the effect efficiency was 36.9% and 23.4%, respectively. The N2O emission fluxes of the two treatments showed similar seasonal variations, with the highest in spring, higher in summer, and lower in autumn and winter. Furthermore, their diurnal variations were the same, the maxima both occurred at 18 o'clock, and the minima appeared at 12 o'clock and 14 o'clock. As for CH4 uptake fluxes, their seasonal variations were similar. The CH4 uptake fluxes were significantly higher in summer and autumn than in spring and autumn, and their diurnal variations were also the same, both went up from 14 o'clock to 18 o'clock and then started to go down until 6 o'clock. The results also indicated that soil N2O emission fluxes were negatively linear-correlated to CH4 uptake fluxes in the broad-leaved Korean pine forest.

Based on the Beijing 325 m meteorological tower, O3, NOx and CO concentrations and meteorological parameters in urban atmospheric boundary layer were measured in July 2002. The variations of O3 concentration were remarkably different among the five levels. Contrasted with the higher levels, the daily variations were clear and the difference values between day and night were large in the lower levels. It was also found that the photochemistry reaction was an important source in boundary layer in daytime and precipitation process could arouse marked change of O3 concentration.

Field experiment was conducted in 2001 rice growing season to understand the effect of organic manure application on CH4 and N2O emissions. Five treatments of fertilizer including urea and NH4HCO3 used as chemical fertilizer (CF), chemical fertilizer + pig manure (CF + PM), chemical fertilizer + cow manure (CF + CM), chemical fertilizer + rapeseed cake (CF + RC) and chemical fertilizer + wheat straw (CF + WS) were dedicated to this experiment. Results from the field observations indicated that application of the organic manure did not change the seasonal pattern of CH4 and N2O emissions but significantly affected the seasonal amounts. Seasonal amount of CH4 emission from the treatments of CF + CM, CF + RC and CF + WS was respectively 45%, 252% and 250% higher than that from the treatment of CF, but the application of pig manure (CF + PM) did not significantly influence the CH4 emission. The N2O emissions, on the other hand, were reduced by 18%, 21% and 18% for the treatments of CF + PM, CF + CM and CF + WS, respectively. Incorporation of rapeseed cake enhanced the N2O emission, yielding an increment of 22%. On a time scale of 20-year period, the integrated global warming potential (GWP) of CH4 + N2O released during the rice growing season for the treatments of CF + RC, CF + WS and CF + CM was respectively 154%, 136% and 17% higher than that for the CF treatment, while a reduction of 10% was obtained for the CF + PM treatment. The calculation of the GWP per unit rice grain yield suggested that the application of pig manure took the slight advantages not only in reducing the GWP but also in improving the grain yield.

The diurnal variation of the atmospheric CO2 at the urban area in Beijing displayed a very clear cycle, generally with the lowest value being recorded at about 15:00 local time and the highest in the nighttime. The differences between the maximums and the minimums ranged from 23.2 to 39.0 mumol.mol-1 in the four seasons and the ones of summer and fall were bigger than that of winter and spring. It showed a large seasonal cycle with a maximum in winter, from 421.5 to 441.0 mumol.mol-1, and a minimum in summer, between 367.4 and 371.6 mumol.mol-1. The peak-to-peak amplitude of atmospheric CO2 in Beijing, controlled mostly by the anthropogenic activities and seasonal variation of vegetation, was higher than that in Xinglong Station, Hebei Province and China Global Atmosphere Watch Baseline Observatory (Waliguan). The concentration of atmospheric CO2 in Beijing increased rapidly at a mean growth rate of 3.7%.a-1 from 1993 to 1995. After displaying a peak of 409.7 +/- 25.9 mumol.mol-1 in 1995, it decreased slowly.

GC-MS was used to measure the greenhouse emission of Inner Mongolia Grassland. The results showed that four kinds of typical semi-arid grasslands in Inner Mongolia had their own special seasonal patterns as the source of atmospheric N2O and CO2 emission and the sink of atmopsheric CH4, which were controlled by seasonal weather variation. Different soil and vegetation types and precipitation influenced the intensity of emission and upatake of the gases. Compared with natural grassland, free grazing decreased CH4 uptake and N2O emission, but increased CO2 emission.

A method for measuring NO and NO2 exchanges between cultivated lands and the atmosphere in a FACE (free-air CO2 enrichment) study is described. With this method, gas is sampled with a technique of static-opaque-chamber and the fluxes of NO and NO2 exchanges are determined by analyzing the NO and NO2 concentrations with a chemiluminescent NOx analyzer. Application of this method in the FACE study of a rice-wheat ecosystem has indicated that reliable data on the exchange fluxes could be obtained. Over the non-waterlogged period of a rice-wheat rotation, net emission of NO from the fields was observed, while net uptake of NO2 occurred. The daily net emission of NO did not correlated with the soil temperature, but negatively depended upon soil moisture (R2 = 0.82, P < 0.001). A significant seasonal variation in the net uptake of NO2 was observed, which was regulated by wheat growth status. The daily uptake of NO2 depended upon both soil temperature and soil moisture. The dependence for each could be described with a parabola function (for soil temperature: R2 = 0.74, P < 0.001; for soil moisture: R2 = 0.69, P < 0.001). An elevation of atmospheric CO2 by 200 +/- 40 mumol.mol-1 mitigated the net emission of NO by 19% (t-test P = 0.096) and might be possible to reduce the net uptake of NO2 by 10% (t-test P = 0.26), which was likely due to the stimulated wheat growth.

Effects of elevated atmospheric CO2 on CH4 and N2O emissions during the paddy rice-growing season were examined in a FACE (free-air carbon dioxide enrichment) study. The emission fluxes of CH4 and N2O from paddy rice fields were measured using methods based on static opaque-chamber and gas chromatography techniques. Synthetic fertilizer N was amended for the rice-growing season at two rates, 150 and 250 kgN.hm-2 and the atmospheric CO2 was enriched by 200 mumol.mol-1. At both N levels, the preliminary results indicate that no significant effect of CO2 enrichment on CH4 and N2O emissions from the rice paddy fields was detected. The result on CH4 emissions is inconsistent with the most literatures, and the result on N2O emissions is consistent with the most literatures.

The latest researches on the effects of elevated atmospheric CO2 on the exchanges of trace gases (e.g., CO2, CH4 and N2O) between the atmosphere and ecosystems were reviewed. The techniques and methods involved in the researches were introduced firstly. Then the review mainly focused upon the results from those studies using the open-top-chamber (OTC) methods and the free-air carbon dioxide enrichment (FACE) system. Generally, elevated atmospheric CO2 may stimulate biomass accumulation, and enlarge C/N ratio in plant tissue so as to reduce the decomposition of organic matter. This action could increase CO2 sequestration in terrestrial ecosystems. Elevated atmospheric CO2 could impact on methanogenic bacteria and CH4 emissions. An increase in CH4 emissions from wetland may appear. The argument among the responses of N2O emissions to elevated CO2, however, was inconsistent. So far, no study on other trace gases was reported. More efforts should be taken in the research on the effects of elevated atmospheric CO2 on the exchange of trace gases.

We firstly introduced the method for determining the net ecosystem exchange fluxes of CO2 (NEE) between croplands and atmosphere, based on field measurements using static opaquechamber/gas chromatography methods was introduced, and the application of this method in the FACE (free-air CO2 enrichment) study to examine the effects of elevated CO2 on the NEE over a typical paddy ecosystem was carried out, because of lacking in observation data for some necessary parameters, e.g., dark maintenance respiration coefficient, only the minimum value of NEE (NEEmin) was calculated based on opaque-chamber measurements. The NEEmin data indicate that CO2 elevated by 200 +/- 40 mumol.mol-1 significantly increased the ecosystem uptake of atmospheric CO2 by a factor ca. 3. To accurately determine the NEE based on opaquechamber measurements, dark maintenance respiration coefficient, above-ground biomass and root: shoot, i.e. R:S, ratio of root to shoot should be observed over the whole growing season.

A method was specially designed and applied for measuring CO2 concentration of soil air over the non-waterlogged period of a rice-wheat rotation on an available area of about 1.6 m2 in a FACE (free-air CO2 enrichment) study. Based on measuring the CO2 concentration over the soil profile of 0-30 cm in depth using this method, the CO2 profile in the soils of wheat fields under elevated and ambient CO2 and the bare land under ambient CO2 was investigated and some preliminary results were obtained. Within 0-30 cm in soil depth, CO2 in the pores of the upper soil layers vertically diffused upwards much more quickly than that in the lower soil layers. During the period with active wheat growth, elevated atmospheric CO2 by 200 +/- 40 mumol.mol-1 significantly increased the CO2 concentration in soil air within 0-30 cm in depth by 14% +/- 5% (t-test, P < 0.001).