The yeasts Cryptococcus laurentii, Trichosporon pullulans, Rhodotorula glutinis andTrichosporon sp.were used to investigate their sensitivity to four fungicides anddifferent concentrations of CO2, as well as their ant...The yeasts Cryptococcus laurentii, Trichosporon pullulans, Rhodotorula glutinis andTrichosporon sp.were used to investigate their sensitivity to four fungicides anddifferent concentrations of CO2, as well as their antagonistic ability to Penicilliumexpansumand Alternariaalternata in vitro when applied with fungicide. There were significantdifferences in sensitivity to the fungicides among the different yeasts(P=0.05). R.glutinis was more sensitive to Deccocil, Iprodione and Stroby as compared to otheryeasts. Combination antagonistic yeasts with fungicide could more significantly enhancebiocontrol ability of the yeasts against the pathogenic fungi in vitro(P = 0.05). C.laurentii was the most effective antagonist among the four yeasts and could completelycontrol spore germination of P.expansum and A.alternata when combined with Stroby at theconcentration of 100 L L-1. The yeasts, except R.glutinis, could grow well on nutrientyeast dextrose agar (NYDA) after 8 d incubation even at 20% CO2 concentration at 25℃.Particularly Trichosporon sp. showeda better adaptability to low temperature as comparedto other antagonists.展开更多
The rise in atmospheric carbon dioxide(C02)concentrations caused by human activities is leading to global climate change,which poses a threat to human development and survival.This study analyzed the distribution of t...The rise in atmospheric carbon dioxide(C02)concentrations caused by human activities is leading to global climate change,which poses a threat to human development and survival.This study analyzed the distribution of the ocean carbon flux with interannual changes and compared it with the climatological ocean carbon flux to deepen our understanding of carbon sources and sinks.To simulate global CO2 concentrations for the years2008-2010,the ocean carbon flux with interannual changes and the climatological ocean carbon flux were used to drive the GEOS-Chem model,an atmospheric chemical transport model.The simulated values were compared with the CO2 concentrations at nine observation stations to explore the influence of interannual changes in the ocean carbon fluxes on the simulated CO2 concentrations.The authors found that the difference between the two simulation results was greater in the Southern Hemisphere all year,and the difference in autumn was the largest.Compared with the observations,the simulated CO2 concentration of the ocean carbon flux with interannual changes is closer to the observations,indicating that this simulation is more accurate.展开更多
The objectives of this study were to investigate the effect of higher CO2 concentrations （500 and 700 μmol mol^-1） in atmosphere on total soil respiration and the contribution of root respiration to total soil resp...The objectives of this study were to investigate the effect of higher CO2 concentrations （500 and 700 μmol mol^-1） in atmosphere on total soil respiration and the contribution of root respiration to total soil respiration during seedling growth of Pinus sylvestris vat. sylvestriformis. During the four growing seasons （May-October） from 1999 to 2003, the seedlings were exposed to elevated concentrations of CO2 in open-top chambers. The total soil respiration and contribution of root respiration were measured using an LI-6400-09 soil CO2 flux chamber on June 15 and October 8, 2003. To separate root respiration from total soil respiration, three PVC cylinders were inserted approximately 30 cm deep into the soil in each chamber. There were marked diurnal changes in air and soil temperatures on June 15. Both the total soil respiration and the soil respiration without roots showed a strong diurnal pattern, increasing from before sunrise to about 14：00 in the afternoon and then decreasing before the next sunrise. No increase in the mean total soil respiration and mean soil respiration with roots severed was observed under the elevated CO2 treatments on June 15, 2003, as compared to the open field and control chamber with ambient CO2. However, on October 8, 2003, the total soil respiration and soil respiration with roots severed in the open field were lower than those in the control and elevated CO2 chambers. The mean contribution of root respiration measured on June 15, 2003, ranged from 8.3% to 30.5% and on October 8, 2003, from 20.6% to 48.6%.展开更多
Studies on the relationship between plant nitrogen content and soil nitrogen reduction under elevated CO2 conditions and with different nitrogen additions in wetland ecosystems are lacking. This study was meant to ass...Studies on the relationship between plant nitrogen content and soil nitrogen reduction under elevated CO2 conditions and with different nitrogen additions in wetland ecosystems are lacking. This study was meant to assess the effects of elevated CO2 concentrations and inorganic nitrogen additions on soil and plant nitrogen cycling. A cultured riparian wetland, alligator weeds, and two duplicated open top chambers （OTCs） with ambient （380μmol/mol） and elevated （700 μmol/mol） CO2 concentrations at low （4 mg/L） and high （6 mg/L） nitrogen fertilization levels were used. The total plant biomass increased by 30.77% and 31.37% at low and high nitrogen fertilization levels, respectively, under elevated CO2 conditions. Plant nitrogen content decreased by 6.54% and 8.86% at low and high nitrogen fertilization levels, respectively. The coefficient of determination （R2） of soil nitrogen contents ranged from 0.81 to 0.96. Under elevated CO2 conditions, plants utilized the assimilated inorganic nitrogen （from the soil） for growth and other internal physiological transformations, which might explain the reduction in plant nitrogen content. A reduction in soil dissolved inorganic nitrogen （DIN） under elevated CO2 conditions might have also caused the reduction in plant nitrogen content. Reduced plant and soil nitrogen contents are to be expected due to the potential exhaustive use of inorganic nitrogen by soil microorganisms even before it can be made available to the soil and plants. The results from this study provide important information to help policy makers make informed decisions on sustainable management of wetlands. Larger-scale field work is recommended in future research.展开更多
High-accuracy continuous measurements of atmospheric concentrations of CO2 were made from May 2016 to December 2017 using the Picarro G2301 analyzer at Xinglong station(40°24′N,117°30′E,940 MSL),150 km nor...High-accuracy continuous measurements of atmospheric concentrations of CO2 were made from May 2016 to December 2017 using the Picarro G2301 analyzer at Xinglong station(40°24′N,117°30′E,940 MSL),150 km northeast of Beijing.The near-ground CO2 measurements were calibrated by standards based on WMO procedures.The regional background measurements were ltered by the robust extraction of baseline signal method to study the seasonal and diurnal cycles.The regional background CO2 concentrations were low in summer.The maximum diffierence between the local sources and regional background CO2 concentrations occurred in summer and autumn,indicating a strong in uence from local sources.Cluster analysis and potential source contribution function analysis showed that the long-distance transport of anthropogenic emissions in the Beijing Tianjin Hebei metropolitan area in uenced the CO2 concentrations in Xinglong,espe-cially in summer.The diurnal variation of CO2 was mainly in uenced by the various vertical transport conditions of the tropospheric atmosphere in a day.展开更多
The regional air quality modeling system RAMS-CMAQ(Regional Atmospheric Modeling System and Models-3 Community Multi-scale Air Quality) was developed by incorporating a vegetation photosynthesis and respiration module...The regional air quality modeling system RAMS-CMAQ(Regional Atmospheric Modeling System and Models-3 Community Multi-scale Air Quality) was developed by incorporating a vegetation photosynthesis and respiration module(VPRM) and used to simulate temporal-spatial variations in atmospheric CO2 concentrations in East Asia,with prescribed surface CO2 fluxes(i.e.,fossil fuel emission,biomass burning,sea-air CO2 exchange,and terrestrial biosphere CO2 flux).Comparison of modeled CO2 mixing ratios with eight ground-based in-situ measurements demonstrated that the model was able to capture most observed CO2 temporal-spatial features.Simulated CO2 concentrations were generally in good agreement with observed concentrations.Results indicated that the accumulated impacts of anthropogenic emissions contributed more to increased CO2 concentrations in urban regions relative to remote locations.Moreover,RAMS-CMAQ analysis demonstrates that surface CO2 concentrations in East Asia are strongly influenced by terrestrial ecosystems.展开更多
CO2 concentrations in different plant communities （larch, birch, lilac, and grassland） were measured during the growing season in the Heilongjiang Forest Botanical Garden to study diurnal variation, seasonal and ann...CO2 concentrations in different plant communities （larch, birch, lilac, and grassland） were measured during the growing season in the Heilongjiang Forest Botanical Garden to study diurnal variation, seasonal and annual dynamics and factors that impact CO2 concentration in different spaces. CO2 concentration in different communities in green lands had an obvious diurnal variation, chronically decreasing, and temperature influenced the lilac area and the grassland. Seasonally, CO2 was lowest in the larch green land （344.03 ±23.03 μmol/mol） and highest in the grassland （360.13 ± 22.43 μmol/mol）. The overall trend in CO2 concentration was autumn 〉 spring 〉 summer; temperature is the main factor controlling variation in CO2 concentrations during the growing season; the CO2 concentration at the larch, birch, lilac, and grassland types of sites was negatively correlated with land surface temperature and air temperature, and the CO2 concentration at the larch and birch sites was positively correlated with atmospheric pressure. Without any obvious annual change law, further study and observation are needed.展开更多
Influences of temperature, humidity, and CO2 concentration on the photosynthesis and respiration of three-year-oldBetula platyphylla was investigated. Light compensation point, saturation point and CO2 compensation po...Influences of temperature, humidity, and CO2 concentration on the photosynthesis and respiration of three-year-oldBetula platyphylla was investigated. Light compensation point, saturation point and CO2 compensation point were also determined. The results showed that the optimal temperature of photosynthesis and dark respiration was 24 °C and 30 °C, respectively, at ambient CO2. When relative humidity was 80%,Betula platyphylla could maintain strong photosynthesis. There was no significant correlation between respiration and relative humidity. The light compensation and saturation point was 25 μmol·m?2·s?1 and 1 375 μmol·m?2·s?1, respectively. The CO2 compensation point was 180 μL·L?1. The results showed thatBetula platyphylla still had potential to assimilate CO2 when CO2 concentration was above 2 400 μL·L?1.展开更多
Seasonal changes in the photosynthetic characteristics of Ammopiptantus mongolicus (Maxim. )Chen f. were studied. When the net photosynthetic rate decreased with the elevation of air temperature, thestomatal conductan...Seasonal changes in the photosynthetic characteristics of Ammopiptantus mongolicus (Maxim. )Chen f. were studied. When the net photosynthetic rate decreased with the elevation of air temperature, thestomatal conductance and stomatal limitation value tended to decline simultaneously, while the interoellularCO2 concentration was increased. According to the two criteria discriminating the stomatal limitation of Photosynthesis suggeSted by Fmrquhar and Sharkey, the seasonal changes in these parameters indicated that the decrease in Pn may not be due to stomatal factor. These studies proved that the relative contents of the large subunit of Rubisco and the photochemical activities correlated with the seasonal changes in the net photosyntheticrate, whieh may show that these two factors contribute primarily to the seasonal changeS in CO2 assimilation.展开更多
The increase of atmospheric CO 2 concentration is indisputable. In such condition, photosynthetic response of leaf is relatively well studied, while the comparison of that between single leaf and whole canopy is less...The increase of atmospheric CO 2 concentration is indisputable. In such condition, photosynthetic response of leaf is relatively well studied, while the comparison of that between single leaf and whole canopy is less emphasized. The stimulation of elevated CO 2 on canopy photosynthesis may be different from that on single leaf level. In this study, leaf and canopy photosynthesis of rice (Oryza sativa L.) were studied throughout the growing season. High CO 2 and temperature had a synergetic stimulation on single leaf photosynthetic rate until grain filling. Photosynthesis of leaf was stimulated by high CO 2, although the stimulation was decreased by higher temperature at grain filling stage. On the other hand, the simulation of elevated CO 2 on canopy photosynthesis leveled off with time. Stimulation at canopy level disappeared by grain filling stage in both temperature treatments. Green leaf area index was not significantly affected by CO 2 at maturity, but greater in plants grown at higher temperature. Leaf nitrogen content decreased with the increase of CO 2 concentration although it was not statistically significant at maturity. Canopy respiration rate increased at flowering stage indicating higher carbon loss. Shading effect caused by leaf development reached maximum at flowering stage. The CO 2 stimulation on photosynthesis was greater in single leaf than in canopy. Since enhanced CO 2 significantly increased biomass of rice stems and panicles, increase in canopy respiration caused diminishment of CO 2 stimulation in canopy net photosynthesis. Leaf nitrogen in the canopy level decreased with CO 2 concentration and may eventually hasten CO 2 stimulation on canopy photosynthesis. Early senescence of canopy leaves in high CO 2 is also a possible cause.展开更多
CO2 concentrations at different heights in a broadleaved/Korean forest (with a mean height of 26 m) were measured with infrared gas analyzer IRGA (model 2250D, LI-COR Inc. and LI-COR, 820) from Aug. to Oct. of 1999, A...CO2 concentrations at different heights in a broadleaved/Korean forest (with a mean height of 26 m) were measured with infrared gas analyzer IRGA (model 2250D, LI-COR Inc. and LI-COR, 820) from Aug. to Oct. of 1999, Apr. to Jul. of 2000, and from Aug. 2002 to Sept. 2003. Based on the collected dada, the diurnal and seasonal dynamics of profiles and storage of carbon dioxide in the forest were analyzed. The diurnal CO2 profiles showed that the vertical distribution of CO2 concentration were different for daytime and nighttime, and the CO2 concentration was highest close to forest floor, no matter at daytime and nighttime. The seasonal profiles of CO2 showed that stratification in the canopy was evident during growth season. CO2 concentrations at different heights (60 m to 2.5 m) had a little change in March, with a difference of 10 mmolmol-1, but had a significant change in July, with a difference of 60 mmolmol-1. In July, there also existed a greater gradient of CO2 concentrations at canopy (22, 26 and 32 m), with a difference of 8 mmolmol-1. The calculated total storage (ΔC/Δt ) of CO2 in the air column with height of 40 m beneath eddy covariance instrument was negative, and made a little contribution to NEE.展开更多
The effects of CO 2 concentration on the morphological and anatomical characters of soybean (Glycine max) leaf were investigated by means of light microscopy and SEM.It was noticed that exomorphology did not show dra...The effects of CO 2 concentration on the morphological and anatomical characters of soybean (Glycine max) leaf were investigated by means of light microscopy and SEM.It was noticed that exomorphology did not show dramatic change,while stomatal density decreased with increasing CO 2 concentration.Under SEM,no epicuticular wax was observed on both abaxial and adaxial sides of the control group as well as on adaxial side of the treatment group.However,leaf surface of abaxial side was noticed to be densely covered with microasterisk epicuticular wax when they were exposed to CO 2 enriched environment.The epicuticular wax deposition was present in equal abundance on both stomatal and nonstomatal areas.Furthermore,leaf thickness increased significantly due largely to the origin of an extra layer of palisade in the treatment group.The results confirmed that CO 2 enrichment might enhance cell division and induce greater quantity of epicuticular wax.展开更多
A study was conducted to determine the responses of soil enzymes （invertase, polyphenol oxidase, catalase, and dehydrogenase） to long-term CO2 enrichment at the Research Station of Changbai Mountain Forest Ecosystem...A study was conducted to determine the responses of soil enzymes （invertase, polyphenol oxidase, catalase, and dehydrogenase） to long-term CO2 enrichment at the Research Station of Changbai Mountain Forest Ecosystems, Chinese Academy of Sciences （42°24＇N, 128°28＇E; 738 m in elevation） in the northeast China during 1999-2006. Three treatments of the CO2 enrichment, designed as 500 μmol·mol-1 CO2 open-top chamber （OTC）, ambient control chamber and unchambered field （approx. 370 μmol·mol^-1CO2）, were conducted with Pinus koraiensis and Pinus sylvestriformis tree species. Soil sampling was made and analyzed separately in spring, summer and autumn in 2006 after the soil enzymes were exposed to elevated CO2 concentration （500 μmol·mol^-1） for eight growing seasons. Results showed that, at elevated CO2 concentration （500 μmol·mol^-1）, the activities of invertase （except for the summer samples of P. koraiensis） presented a remarkable decline in all growing seasons, while the activities of dehydrogenase had an increase but only part of the results was remarkable; the activities of polyphenol oxidase in P. sylvestriformis rhizosphere showed a remarkable decrease; the catalase activities increased in spring, while in turn were decline in other seasons. This study also revealed that the soil enzyme activities are significantly correlated with the tree species under the CO2 enhancement.展开更多
[Objective] This study was to evaluate the impact of a new controlled release anti-drip nano-PE-film （CRANPF） on greenhouse environmental factors. [Method] CRANPF and conventional anti-drip PE film （CLAPF） were co...[Objective] This study was to evaluate the impact of a new controlled release anti-drip nano-PE-film （CRANPF） on greenhouse environmental factors. [Method] CRANPF and conventional anti-drip PE film （CLAPF） were compared in terms of air temperature, light intensity and CO2 concentration by the leafy agriculture greenhouse intelligent monitoring system. [Result] Compared to CLAPF, the air temperature rose slower in CRANPF during hot weather and had better photosynthesis efficiency. [Conclusion] Compared with ODLAPF, CRANPF has better perfor- mance and more extensive application prospects.展开更多
An experiments were carried out with treatments differing in nitrogen supply （0, 5 and 15 g N/m^2） and CO2 levels （350 and 700 μmol/mol） using OTC （open top chamber） equipment to investigate the biomass of Cala...An experiments were carried out with treatments differing in nitrogen supply （0, 5 and 15 g N/m^2） and CO2 levels （350 and 700 μmol/mol） using OTC （open top chamber） equipment to investigate the biomass of Calamagrostis angustifolia and soil active carbon contents after two years. The results showed that elevated CO2 concentration increased the biomass of C. angustifolia and the magnitude of response varied with each growth period. Elevated CO2 concentration has increased aboveground biomass by 16.7% and 17.6% during the jointing and heading periods and only 3.5% and 9.4% during dough and maturity periods. The increases in belowground biomass due to CO2 elevation was 26.5%, 34.0% and 28.7% during the heading, dough and maturity periods, respectively. The responses of biomass to enhanced CO2 concentrations are differed in N levels. Both the increase of aboveground biomass and belowground biomass were greater under high level of N supply （15 g N/m^2）. Elevated CO2 concentration also increased the allocation of biomass and carbon in root. Under elevated CO2 concentration, the average values of active carbon tended to increase. The increases of soil active soil contents followed the sequence of microbial biomass carbon （10.6%） 〉 dissolved organic carbon （7.5%） 〉 labile oxidable carbon （6.6%） 〉 carbohydrate carbon （4.1%）. Stepwise regressions indicated there were significant correlations between the soil active carbon contents and plant biomass. Particularly, microbial biomass carbon, labile oxidable carbon and carbohydrate carbon were found to be correlated with belowground biomass, while dissolved organic carbon has correlation with aboveground biomass. Therefore, increased biomass was regarded as the main driving force for the increase in soil active organic carbon under elevated CO2 concentration.展开更多
The carbon dioxide （CO2） concentrations and fluxes measured at a height of 17.5 m above the ground by a sonic anemometer and an open-path gas analyzer at an urban residential site in Seoul, Korea from February 2011 ...The carbon dioxide （CO2） concentrations and fluxes measured at a height of 17.5 m above the ground by a sonic anemometer and an open-path gas analyzer at an urban residential site in Seoul, Korea from February 2011 to January 2012 were analyzed. The annual mean CO2 concentration was found to be 750 mg m-3, with a maximum monthly mean concentration of 827 mg m-3 in January and a minimum value of 679 mg m-3 in August. Meanwhile, the annual mean CO2 flux was found to be 0.45 mg m-2 s-1, with a maximum monthly mean flux of 0.91 mg m-2 s-1 in January and a minimum value of 0.19 mg m-2 s-1 in June. The hourly mean CO2 concentration was found to show a significant diurnal variation; a maximum at 0700-0900 LST and a minimum at 1400-1600 LST, with a large diurnal range in winter and a small one in summer, mainly caused by diurnal changes in mixing height, CO2 flux, and surface complexity. The hourly mean CO2 flux was also found to show a significant diurnal variation, but it showed two maxima at 0700-0900 LST and 2100-2400 LST, and two minima at 1100-1500 LST and 0300-0500 LST, mainly caused by a diurnal pattern in CO2 emissions and sinks from road traffic, domestic heating and cooking by liquefied natural gas use, and the different horizontal distribution of CO2 sources and sinks near the site. Differential advection with respect to wind direction was also found to be a cause of diurnal variations in both the CO2 concentration and flux.展开更多
Salinity is a major soil contamination problem in Australia. To explore salinity remediation, we evaluated the concentrations of sodium （Na）, potassium （K）, magnesium （Mg）, and calcium （Ca） in roots and shoots...Salinity is a major soil contamination problem in Australia. To explore salinity remediation, we evaluated the concentrations of sodium （Na）, potassium （K）, magnesium （Mg）, and calcium （Ca） in roots and shoots and in the supporting soil of the naturally occurring grasses, Cynodon dactylon and Thinopyrurn ponticum, at two salt-affected sites, Gumble and Cundumbul in central-western New South Wales, Australia. The physiological parameters of the two grass species, including net photosynthetic rate （Pn）, stomatal conductance （gs）, and intercellular CO2 concentration （Ci）, were investigated using one mature leaf from C. dactylon and T. ponticum populations. Increasing salinity levels in the topsoil had a significant influence on Ci and gs, whereas no significant effect occurred on Pn in C. dactylon and T. ponticum. The Pn values in C. dactylon and T. ponticum were greater at Cundumbul than at Gumble. The greater Mg concentration facilitated greater Pn in C. dactylon and T. ponticum populations at Cundumbul than Gumble. With increasing salinity levels in the soil, Na accumulation increased in C. dactylon and T. ponticum. The ratio between K and Na was ~ 1 in roots and shoots of both populations irrespective of the sites. Bioaccumulation factor （BF） and translocation factor （TF） results revealed that K and Na translocations were significantly higher in T. ponticum than in C. dactylon, whereas Ca and Mg translocations were significantly higher in C. dactylon than in T. ponticum. Accumulation of Na, K, Mg, and Ca ions was higher in T. ponticum than in C. dactylon; therefore, we suggest that T. ponticum as a greater salt accumulator than C. dactylon could be used for revegetation and phytoremediation of the salt-affected soils.展开更多
The annual series of δ13C were measured in tree rings of three Cryptomeria fortunei disks （OF-1, OF-2, and OF- 3） collected from West Tianmu Mountain, Zhejiang Province, China, according to cross-dating tree ring a...The annual series of δ13C were measured in tree rings of three Cryptomeria fortunei disks （OF-1, OF-2, and OF- 3） collected from West Tianmu Mountain, Zhejiang Province, China, according to cross-dating tree ring ages. There was no obvious decreasing trend of the δ13C annual time series of CF-2 before 1835. However, from 1835 to 1982 the three tree ring δ13C annual series exhibited similar decreasing trends that were significantly （P ≤ 0.001） correlated. The distribution characteristics of a scatter diagram between estimated δ13C series of CF-2 from modeling and the atmospheric CO2 concentration extracted from the Law Dome ice core from 1840 to 1978 were analyzed and a curvilinear regression equation for reconstructing atmospheric CO2 concentration was established with R2 = 0.98. Also, a test of independent samples indicated that between 1685 and 1839 the reconstructed atmospheric CO2 concentration .using the δ13C series of CF-2 had a close relationship with the Law Dome and Siple ice cores, with a standard deviation of 1.98. The general increasing trend of the reconstructed atmospheric CO2 concentration closely reflected the 10ng-term variation of atmospheric CO2 concentration recorded both before and after the Industrial Revolution. Between 1685 and 1840 the evaluated atmospheric CO2 concentration was stable, but after 1840 it exhibited a rapid increase. Given a longer δ13C annual time series of tree rings, it was feasible to rebuild a representative time series to describe the atmospheric CO2 concentration for an earlier period and for years that were not in the ice core record.展开更多
Mine refuge chambers are used to shield miners who fail to escape from the mine when incidents occur. Environment maintaining system plays a key role in stabilizing thermal environment of a mine refuge chamber against...Mine refuge chambers are used to shield miners who fail to escape from the mine when incidents occur. Environment maintaining system plays a key role in stabilizing thermal environment of a mine refuge chamber against heat emitted from metabolism and transferred from outside. The safety and comfort of refugees are closely related to the environment maintaining system design. In order to improve the comfort of refugees, optimization on the environment maintaining system has been done based on the previous work. To evaluate the environment of the chamber, eight volunteers were involved into the experiment. Under close observation and safety protection, they lived in a heat-isolated test chamber for 106 hours. The volunteers were asked to maintain low level of activities to simulate refugees＇ situation. It shows that the environment maintaining system worked well and the temperature, relative humidity and emitted harmful air content such as CO2 and CO were all kept in the safety level, and no discomfort was felt by volunteers at all.展开更多
Successive filtration and comparison show that the stratosphere air temperature in 10 hPa-layer of the Northern Hemisphere （NH） in July continuously increases,which is associated to the increases in greenhouse gases...Successive filtration and comparison show that the stratosphere air temperature in 10 hPa-layer of the Northern Hemisphere （NH） in July continuously increases,which is associated to the increases in greenhouse gases mostly CO2,volcanic activities,and solar activity,demonstrating the follows.（a） The increase in CO2 concentration is largely consistent with that of the stratosphere air temperature in 10 hPa-layer of the NH in July.However,the increase in the air temperature is not in a linear pattern,during which several cooling events interrupt.The cooling events between late 1960s and late 1970s are remarkable ones and so is the one before mid 1990s.Analysis shows that these events are induced by volcanic activities and solar activity.（b） The CO2-free variation in the stratosphere air temperature in 10 hPa-layer of the NH is consistent with that of the solar magnetic index.The wave crests and wave troughs of the two curves are consistent in phase,and the curve of solar magnetic index leads the other slightly.In other words,when the solar magnetic pole is southward,a warming in the NH stratosphere corresponds;and on the contrary,the northward solar magnetic pole corresponds to a cooling event.The variation in solar magnetic polarity strongly impacts the variation in the stratosphere temperature.展开更多
基金supported by the National Science Fund for Distinguished Young Scholars of China(30225030)the National Natural Science Foundation of China(30170663)the Natural Science Foundation of Beijing(6012005).
文摘The yeasts Cryptococcus laurentii, Trichosporon pullulans, Rhodotorula glutinis andTrichosporon sp.were used to investigate their sensitivity to four fungicides anddifferent concentrations of CO2, as well as their antagonistic ability to Penicilliumexpansumand Alternariaalternata in vitro when applied with fungicide. There were significantdifferences in sensitivity to the fungicides among the different yeasts(P=0.05). R.glutinis was more sensitive to Deccocil, Iprodione and Stroby as compared to otheryeasts. Combination antagonistic yeasts with fungicide could more significantly enhancebiocontrol ability of the yeasts against the pathogenic fungi in vitro(P = 0.05). C.laurentii was the most effective antagonist among the four yeasts and could completelycontrol spore germination of P.expansum and A.alternata when combined with Stroby at theconcentration of 100 L L-1. The yeasts, except R.glutinis, could grow well on nutrientyeast dextrose agar (NYDA) after 8 d incubation even at 20% CO2 concentration at 25℃.Particularly Trichosporon sp. showeda better adaptability to low temperature as comparedto other antagonists.
基金partially supported by the National Key Research and Development Program of China [grant number 2016YFA0600203]the National Natural Science Foundation of China [grant number 41575100]
文摘The rise in atmospheric carbon dioxide(C02)concentrations caused by human activities is leading to global climate change,which poses a threat to human development and survival.This study analyzed the distribution of the ocean carbon flux with interannual changes and compared it with the climatological ocean carbon flux to deepen our understanding of carbon sources and sinks.To simulate global CO2 concentrations for the years2008-2010,the ocean carbon flux with interannual changes and the climatological ocean carbon flux were used to drive the GEOS-Chem model,an atmospheric chemical transport model.The simulated values were compared with the CO2 concentrations at nine observation stations to explore the influence of interannual changes in the ocean carbon fluxes on the simulated CO2 concentrations.The authors found that the difference between the two simulation results was greater in the Southern Hemisphere all year,and the difference in autumn was the largest.Compared with the observations,the simulated CO2 concentration of the ocean carbon flux with interannual changes is closer to the observations,indicating that this simulation is more accurate.
基金Project supported by the Knowledge Innovation Project of the Chinese Academy of Sciences (No.KZCX2-YW-416)National NaturM Science Foundation of China (No.90411020)
文摘The objectives of this study were to investigate the effect of higher CO2 concentrations （500 and 700 μmol mol^-1） in atmosphere on total soil respiration and the contribution of root respiration to total soil respiration during seedling growth of Pinus sylvestris vat. sylvestriformis. During the four growing seasons （May-October） from 1999 to 2003, the seedlings were exposed to elevated concentrations of CO2 in open-top chambers. The total soil respiration and contribution of root respiration were measured using an LI-6400-09 soil CO2 flux chamber on June 15 and October 8, 2003. To separate root respiration from total soil respiration, three PVC cylinders were inserted approximately 30 cm deep into the soil in each chamber. There were marked diurnal changes in air and soil temperatures on June 15. Both the total soil respiration and the soil respiration without roots showed a strong diurnal pattern, increasing from before sunrise to about 14：00 in the afternoon and then decreasing before the next sunrise. No increase in the mean total soil respiration and mean soil respiration with roots severed was observed under the elevated CO2 treatments on June 15, 2003, as compared to the open field and control chamber with ambient CO2. However, on October 8, 2003, the total soil respiration and soil respiration with roots severed in the open field were lower than those in the control and elevated CO2 chambers. The mean contribution of root respiration measured on June 15, 2003, ranged from 8.3% to 30.5% and on October 8, 2003, from 20.6% to 48.6%.
基金supported by the Fundamental Research Funds for the Central Universities(Grant No.2009B17714)the National Program on Key Basic Research Projects of China(Grant No.2012CB719800)
文摘Studies on the relationship between plant nitrogen content and soil nitrogen reduction under elevated CO2 conditions and with different nitrogen additions in wetland ecosystems are lacking. This study was meant to assess the effects of elevated CO2 concentrations and inorganic nitrogen additions on soil and plant nitrogen cycling. A cultured riparian wetland, alligator weeds, and two duplicated open top chambers （OTCs） with ambient （380μmol/mol） and elevated （700 μmol/mol） CO2 concentrations at low （4 mg/L） and high （6 mg/L） nitrogen fertilization levels were used. The total plant biomass increased by 30.77% and 31.37% at low and high nitrogen fertilization levels, respectively, under elevated CO2 conditions. Plant nitrogen content decreased by 6.54% and 8.86% at low and high nitrogen fertilization levels, respectively. The coefficient of determination （R2） of soil nitrogen contents ranged from 0.81 to 0.96. Under elevated CO2 conditions, plants utilized the assimilated inorganic nitrogen （from the soil） for growth and other internal physiological transformations, which might explain the reduction in plant nitrogen content. A reduction in soil dissolved inorganic nitrogen （DIN） under elevated CO2 conditions might have also caused the reduction in plant nitrogen content. Reduced plant and soil nitrogen contents are to be expected due to the potential exhaustive use of inorganic nitrogen by soil microorganisms even before it can be made available to the soil and plants. The results from this study provide important information to help policy makers make informed decisions on sustainable management of wetlands. Larger-scale field work is recommended in future research.
基金funded by the National Key Research and Development Program of China [grant numbers2017YFB0504000 and 2017YFC1501701]the National Natural Science Foundation of China [grant number 41575034]
文摘High-accuracy continuous measurements of atmospheric concentrations of CO2 were made from May 2016 to December 2017 using the Picarro G2301 analyzer at Xinglong station(40°24′N,117°30′E,940 MSL),150 km northeast of Beijing.The near-ground CO2 measurements were calibrated by standards based on WMO procedures.The regional background measurements were ltered by the robust extraction of baseline signal method to study the seasonal and diurnal cycles.The regional background CO2 concentrations were low in summer.The maximum diffierence between the local sources and regional background CO2 concentrations occurred in summer and autumn,indicating a strong in uence from local sources.Cluster analysis and potential source contribution function analysis showed that the long-distance transport of anthropogenic emissions in the Beijing Tianjin Hebei metropolitan area in uenced the CO2 concentrations in Xinglong,espe-cially in summer.The diurnal variation of CO2 was mainly in uenced by the various vertical transport conditions of the tropospheric atmosphere in a day.
基金supported by the Strategic Priority Research Program-Climate Change:Carbon Budget and Relevant Issues (Grant No.XDA05040404)the National Natural Science Foundation of China (Grant No.41130528)
文摘The regional air quality modeling system RAMS-CMAQ(Regional Atmospheric Modeling System and Models-3 Community Multi-scale Air Quality) was developed by incorporating a vegetation photosynthesis and respiration module(VPRM) and used to simulate temporal-spatial variations in atmospheric CO2 concentrations in East Asia,with prescribed surface CO2 fluxes(i.e.,fossil fuel emission,biomass burning,sea-air CO2 exchange,and terrestrial biosphere CO2 flux).Comparison of modeled CO2 mixing ratios with eight ground-based in-situ measurements demonstrated that the model was able to capture most observed CO2 temporal-spatial features.Simulated CO2 concentrations were generally in good agreement with observed concentrations.Results indicated that the accumulated impacts of anthropogenic emissions contributed more to increased CO2 concentrations in urban regions relative to remote locations.Moreover,RAMS-CMAQ analysis demonstrates that surface CO2 concentrations in East Asia are strongly influenced by terrestrial ecosystems.
文摘CO2 concentrations in different plant communities （larch, birch, lilac, and grassland） were measured during the growing season in the Heilongjiang Forest Botanical Garden to study diurnal variation, seasonal and annual dynamics and factors that impact CO2 concentration in different spaces. CO2 concentration in different communities in green lands had an obvious diurnal variation, chronically decreasing, and temperature influenced the lilac area and the grassland. Seasonally, CO2 was lowest in the larch green land （344.03 ±23.03 μmol/mol） and highest in the grassland （360.13 ± 22.43 μmol/mol）. The overall trend in CO2 concentration was autumn 〉 spring 〉 summer; temperature is the main factor controlling variation in CO2 concentrations during the growing season; the CO2 concentration at the larch, birch, lilac, and grassland types of sites was negatively correlated with land surface temperature and air temperature, and the CO2 concentration at the larch and birch sites was positively correlated with atmospheric pressure. Without any obvious annual change law, further study and observation are needed.
基金This paper was supported by the National Natural Science Foundation of China (No. 39970627) and the Key Project of State Department of Science Technology (2002BA515B05).
文摘Influences of temperature, humidity, and CO2 concentration on the photosynthesis and respiration of three-year-oldBetula platyphylla was investigated. Light compensation point, saturation point and CO2 compensation point were also determined. The results showed that the optimal temperature of photosynthesis and dark respiration was 24 °C and 30 °C, respectively, at ambient CO2. When relative humidity was 80%,Betula platyphylla could maintain strong photosynthesis. There was no significant correlation between respiration and relative humidity. The light compensation and saturation point was 25 μmol·m?2·s?1 and 1 375 μmol·m?2·s?1, respectively. The CO2 compensation point was 180 μL·L?1. The results showed thatBetula platyphylla still had potential to assimilate CO2 when CO2 concentration was above 2 400 μL·L?1.
文摘Seasonal changes in the photosynthetic characteristics of Ammopiptantus mongolicus (Maxim. )Chen f. were studied. When the net photosynthetic rate decreased with the elevation of air temperature, thestomatal conductance and stomatal limitation value tended to decline simultaneously, while the interoellularCO2 concentration was increased. According to the two criteria discriminating the stomatal limitation of Photosynthesis suggeSted by Fmrquhar and Sharkey, the seasonal changes in these parameters indicated that the decrease in Pn may not be due to stomatal factor. These studies proved that the relative contents of the large subunit of Rubisco and the photochemical activities correlated with the seasonal changes in the net photosyntheticrate, whieh may show that these two factors contribute primarily to the seasonal changeS in CO2 assimilation.
文摘The increase of atmospheric CO 2 concentration is indisputable. In such condition, photosynthetic response of leaf is relatively well studied, while the comparison of that between single leaf and whole canopy is less emphasized. The stimulation of elevated CO 2 on canopy photosynthesis may be different from that on single leaf level. In this study, leaf and canopy photosynthesis of rice (Oryza sativa L.) were studied throughout the growing season. High CO 2 and temperature had a synergetic stimulation on single leaf photosynthetic rate until grain filling. Photosynthesis of leaf was stimulated by high CO 2, although the stimulation was decreased by higher temperature at grain filling stage. On the other hand, the simulation of elevated CO 2 on canopy photosynthesis leveled off with time. Stimulation at canopy level disappeared by grain filling stage in both temperature treatments. Green leaf area index was not significantly affected by CO 2 at maturity, but greater in plants grown at higher temperature. Leaf nitrogen content decreased with the increase of CO 2 concentration although it was not statistically significant at maturity. Canopy respiration rate increased at flowering stage indicating higher carbon loss. Shading effect caused by leaf development reached maximum at flowering stage. The CO 2 stimulation on photosynthesis was greater in single leaf than in canopy. Since enhanced CO 2 significantly increased biomass of rice stems and panicles, increase in canopy respiration caused diminishment of CO 2 stimulation in canopy net photosynthesis. Leaf nitrogen in the canopy level decreased with CO 2 concentration and may eventually hasten CO 2 stimulation on canopy photosynthesis. Early senescence of canopy leaves in high CO 2 is also a possible cause.
基金This study is supported by The Development Plan of State Key Fundamental Research of China (973) (contract No. 2002CB412502),by Knowledge Innovation Project of CAS (KZCX1-SW-01-03) and by Natural Science Foundation of China (30170167).
文摘CO2 concentrations at different heights in a broadleaved/Korean forest (with a mean height of 26 m) were measured with infrared gas analyzer IRGA (model 2250D, LI-COR Inc. and LI-COR, 820) from Aug. to Oct. of 1999, Apr. to Jul. of 2000, and from Aug. 2002 to Sept. 2003. Based on the collected dada, the diurnal and seasonal dynamics of profiles and storage of carbon dioxide in the forest were analyzed. The diurnal CO2 profiles showed that the vertical distribution of CO2 concentration were different for daytime and nighttime, and the CO2 concentration was highest close to forest floor, no matter at daytime and nighttime. The seasonal profiles of CO2 showed that stratification in the canopy was evident during growth season. CO2 concentrations at different heights (60 m to 2.5 m) had a little change in March, with a difference of 10 mmolmol-1, but had a significant change in July, with a difference of 60 mmolmol-1. In July, there also existed a greater gradient of CO2 concentrations at canopy (22, 26 and 32 m), with a difference of 8 mmolmol-1. The calculated total storage (ΔC/Δt ) of CO2 in the air column with height of 40 m beneath eddy covariance instrument was negative, and made a little contribution to NEE.
文摘The effects of CO 2 concentration on the morphological and anatomical characters of soybean (Glycine max) leaf were investigated by means of light microscopy and SEM.It was noticed that exomorphology did not show dramatic change,while stomatal density decreased with increasing CO 2 concentration.Under SEM,no epicuticular wax was observed on both abaxial and adaxial sides of the control group as well as on adaxial side of the treatment group.However,leaf surface of abaxial side was noticed to be densely covered with microasterisk epicuticular wax when they were exposed to CO 2 enriched environment.The epicuticular wax deposition was present in equal abundance on both stomatal and nonstomatal areas.Furthermore,leaf thickness increased significantly due largely to the origin of an extra layer of palisade in the treatment group.The results confirmed that CO 2 enrichment might enhance cell division and induce greater quantity of epicuticular wax.
基金This research was supported by National Basic Research Program of China (No.2002CB412502)Project of Key Pro-gram of the National Science Foundation of China (No.90411020)Natural Science Foundation of China (No.30400051)
文摘A study was conducted to determine the responses of soil enzymes （invertase, polyphenol oxidase, catalase, and dehydrogenase） to long-term CO2 enrichment at the Research Station of Changbai Mountain Forest Ecosystems, Chinese Academy of Sciences （42°24＇N, 128°28＇E; 738 m in elevation） in the northeast China during 1999-2006. Three treatments of the CO2 enrichment, designed as 500 μmol·mol-1 CO2 open-top chamber （OTC）, ambient control chamber and unchambered field （approx. 370 μmol·mol^-1CO2）, were conducted with Pinus koraiensis and Pinus sylvestriformis tree species. Soil sampling was made and analyzed separately in spring, summer and autumn in 2006 after the soil enzymes were exposed to elevated CO2 concentration （500 μmol·mol^-1） for eight growing seasons. Results showed that, at elevated CO2 concentration （500 μmol·mol^-1）, the activities of invertase （except for the summer samples of P. koraiensis） presented a remarkable decline in all growing seasons, while the activities of dehydrogenase had an increase but only part of the results was remarkable; the activities of polyphenol oxidase in P. sylvestriformis rhizosphere showed a remarkable decrease; the catalase activities increased in spring, while in turn were decline in other seasons. This study also revealed that the soil enzyme activities are significantly correlated with the tree species under the CO2 enhancement.
文摘[Objective] This study was to evaluate the impact of a new controlled release anti-drip nano-PE-film （CRANPF） on greenhouse environmental factors. [Method] CRANPF and conventional anti-drip PE film （CLAPF） were compared in terms of air temperature, light intensity and CO2 concentration by the leafy agriculture greenhouse intelligent monitoring system. [Result] Compared to CLAPF, the air temperature rose slower in CRANPF during hot weather and had better photosynthesis efficiency. [Conclusion] Compared with ODLAPF, CRANPF has better perfor- mance and more extensive application prospects.
基金supported by the Chinese Academy of Sciences (No KZCX2-YW-309)the National Basic Research Program (973) of China (No 2004CB418507)
文摘An experiments were carried out with treatments differing in nitrogen supply （0, 5 and 15 g N/m^2） and CO2 levels （350 and 700 μmol/mol） using OTC （open top chamber） equipment to investigate the biomass of Calamagrostis angustifolia and soil active carbon contents after two years. The results showed that elevated CO2 concentration increased the biomass of C. angustifolia and the magnitude of response varied with each growth period. Elevated CO2 concentration has increased aboveground biomass by 16.7% and 17.6% during the jointing and heading periods and only 3.5% and 9.4% during dough and maturity periods. The increases in belowground biomass due to CO2 elevation was 26.5%, 34.0% and 28.7% during the heading, dough and maturity periods, respectively. The responses of biomass to enhanced CO2 concentrations are differed in N levels. Both the increase of aboveground biomass and belowground biomass were greater under high level of N supply （15 g N/m^2）. Elevated CO2 concentration also increased the allocation of biomass and carbon in root. Under elevated CO2 concentration, the average values of active carbon tended to increase. The increases of soil active soil contents followed the sequence of microbial biomass carbon （10.6%） 〉 dissolved organic carbon （7.5%） 〉 labile oxidable carbon （6.6%） 〉 carbohydrate carbon （4.1%）. Stepwise regressions indicated there were significant correlations between the soil active carbon contents and plant biomass. Particularly, microbial biomass carbon, labile oxidable carbon and carbohydrate carbon were found to be correlated with belowground biomass, while dissolved organic carbon has correlation with aboveground biomass. Therefore, increased biomass was regarded as the main driving force for the increase in soil active organic carbon under elevated CO2 concentration.
基金funded by the Korea Meteorological Administration Research and Development Program under the Weather Information Service Engine (WISE) project (Grant No.153-3100-3133-302-350)
文摘The carbon dioxide （CO2） concentrations and fluxes measured at a height of 17.5 m above the ground by a sonic anemometer and an open-path gas analyzer at an urban residential site in Seoul, Korea from February 2011 to January 2012 were analyzed. The annual mean CO2 concentration was found to be 750 mg m-3, with a maximum monthly mean concentration of 827 mg m-3 in January and a minimum value of 679 mg m-3 in August. Meanwhile, the annual mean CO2 flux was found to be 0.45 mg m-2 s-1, with a maximum monthly mean flux of 0.91 mg m-2 s-1 in January and a minimum value of 0.19 mg m-2 s-1 in June. The hourly mean CO2 concentration was found to show a significant diurnal variation; a maximum at 0700-0900 LST and a minimum at 1400-1600 LST, with a large diurnal range in winter and a small one in summer, mainly caused by diurnal changes in mixing height, CO2 flux, and surface complexity. The hourly mean CO2 flux was also found to show a significant diurnal variation, but it showed two maxima at 0700-0900 LST and 2100-2400 LST, and two minima at 1100-1500 LST and 0300-0500 LST, mainly caused by a diurnal pattern in CO2 emissions and sinks from road traffic, domestic heating and cooking by liquefied natural gas use, and the different horizontal distribution of CO2 sources and sinks near the site. Differential advection with respect to wind direction was also found to be a cause of diurnal variations in both the CO2 concentration and flux.
文摘Salinity is a major soil contamination problem in Australia. To explore salinity remediation, we evaluated the concentrations of sodium （Na）, potassium （K）, magnesium （Mg）, and calcium （Ca） in roots and shoots and in the supporting soil of the naturally occurring grasses, Cynodon dactylon and Thinopyrurn ponticum, at two salt-affected sites, Gumble and Cundumbul in central-western New South Wales, Australia. The physiological parameters of the two grass species, including net photosynthetic rate （Pn）, stomatal conductance （gs）, and intercellular CO2 concentration （Ci）, were investigated using one mature leaf from C. dactylon and T. ponticum populations. Increasing salinity levels in the topsoil had a significant influence on Ci and gs, whereas no significant effect occurred on Pn in C. dactylon and T. ponticum. The Pn values in C. dactylon and T. ponticum were greater at Cundumbul than at Gumble. The greater Mg concentration facilitated greater Pn in C. dactylon and T. ponticum populations at Cundumbul than Gumble. With increasing salinity levels in the soil, Na accumulation increased in C. dactylon and T. ponticum. The ratio between K and Na was ~ 1 in roots and shoots of both populations irrespective of the sites. Bioaccumulation factor （BF） and translocation factor （TF） results revealed that K and Na translocations were significantly higher in T. ponticum than in C. dactylon, whereas Ca and Mg translocations were significantly higher in C. dactylon than in T. ponticum. Accumulation of Na, K, Mg, and Ca ions was higher in T. ponticum than in C. dactylon; therefore, we suggest that T. ponticum as a greater salt accumulator than C. dactylon could be used for revegetation and phytoremediation of the salt-affected soils.
基金Project supported by the National Natural Science Foundation of China (No. 49771001).
文摘The annual series of δ13C were measured in tree rings of three Cryptomeria fortunei disks （OF-1, OF-2, and OF- 3） collected from West Tianmu Mountain, Zhejiang Province, China, according to cross-dating tree ring ages. There was no obvious decreasing trend of the δ13C annual time series of CF-2 before 1835. However, from 1835 to 1982 the three tree ring δ13C annual series exhibited similar decreasing trends that were significantly （P ≤ 0.001） correlated. The distribution characteristics of a scatter diagram between estimated δ13C series of CF-2 from modeling and the atmospheric CO2 concentration extracted from the Law Dome ice core from 1840 to 1978 were analyzed and a curvilinear regression equation for reconstructing atmospheric CO2 concentration was established with R2 = 0.98. Also, a test of independent samples indicated that between 1685 and 1839 the reconstructed atmospheric CO2 concentration .using the δ13C series of CF-2 had a close relationship with the Law Dome and Siple ice cores, with a standard deviation of 1.98. The general increasing trend of the reconstructed atmospheric CO2 concentration closely reflected the 10ng-term variation of atmospheric CO2 concentration recorded both before and after the Industrial Revolution. Between 1685 and 1840 the evaluated atmospheric CO2 concentration was stable, but after 1840 it exhibited a rapid increase. Given a longer δ13C annual time series of tree rings, it was feasible to rebuild a representative time series to describe the atmospheric CO2 concentration for an earlier period and for years that were not in the ice core record.
文摘Mine refuge chambers are used to shield miners who fail to escape from the mine when incidents occur. Environment maintaining system plays a key role in stabilizing thermal environment of a mine refuge chamber against heat emitted from metabolism and transferred from outside. The safety and comfort of refugees are closely related to the environment maintaining system design. In order to improve the comfort of refugees, optimization on the environment maintaining system has been done based on the previous work. To evaluate the environment of the chamber, eight volunteers were involved into the experiment. Under close observation and safety protection, they lived in a heat-isolated test chamber for 106 hours. The volunteers were asked to maintain low level of activities to simulate refugees＇ situation. It shows that the environment maintaining system worked well and the temperature, relative humidity and emitted harmful air content such as CO2 and CO were all kept in the safety level, and no discomfort was felt by volunteers at all.
基金supported by the National Natural Science Foundation of China (Nos. 40875041,40631006,40975038)
文摘Successive filtration and comparison show that the stratosphere air temperature in 10 hPa-layer of the Northern Hemisphere （NH） in July continuously increases,which is associated to the increases in greenhouse gases mostly CO2,volcanic activities,and solar activity,demonstrating the follows.（a） The increase in CO2 concentration is largely consistent with that of the stratosphere air temperature in 10 hPa-layer of the NH in July.However,the increase in the air temperature is not in a linear pattern,during which several cooling events interrupt.The cooling events between late 1960s and late 1970s are remarkable ones and so is the one before mid 1990s.Analysis shows that these events are induced by volcanic activities and solar activity.（b） The CO2-free variation in the stratosphere air temperature in 10 hPa-layer of the NH is consistent with that of the solar magnetic index.The wave crests and wave troughs of the two curves are consistent in phase,and the curve of solar magnetic index leads the other slightly.In other words,when the solar magnetic pole is southward,a warming in the NH stratosphere corresponds;and on the contrary,the northward solar magnetic pole corresponds to a cooling event.The variation in solar magnetic polarity strongly impacts the variation in the stratosphere temperature.
