Stored nonstructural carbohydrates(NSC)indicate a balance between photosynthetic carbon(C)assimilation and growth investment or loss through respiration and root exudation.They play an important role in plant function...Stored nonstructural carbohydrates(NSC)indicate a balance between photosynthetic carbon(C)assimilation and growth investment or loss through respiration and root exudation.They play an important role in plant function and whole-plant level C cycling.CO_(2)elevation and nitrogen(N)deposition,which are two major environmental issues worldwide,aff ect plant photosynthetic C assimilation and C release in forest ecosystems.However,information regarding the eff ect of CO_(2)elevation and N deposition on NSC storage in diff erent organs remains limited,especially regarding the trade-off between growth and NSC reserves.Therefore,here we analyzed the variations in the NSC storage in diff erent organs of Chinese fi r(Cunninghamia lanceolata)under CO_(2)elevation and N addition and found that NSC concentrations and contents in all organs of Chinese fi r saplings increased remarkably under CO_(2)elevation.However,N addition induced diff erential accumulation of NSC among various organs.Specifi cally,N addition decreased the NSC concentrations of needles,branches,stems,and fi ne roots,but increased the NSC contents of branches and coarse roots.The increase in the NSC contents of roots was more pronounced than that in the NSC content of aboveground organs under CO_(2)elevation.The role of N addition in the increase in the structural biomass of aboveground organs was greater than that in the increase in the structural biomass of roots.This result indicated that a diff erent tradeoff between growth and NSC storage occurred to alleviate resource limitations under CO_(2)elevation and N addition and highlights the importance of separating biomass into structural biomass and NSC reserves when investigating the eff ects of environmental change on biomass allocation.展开更多
One-year-old seedlings of Pinus koraiensis, Pinus sylvestriformis, Phellodendron amurense were grown in open-top chambers (OTCs) with 700 and 500 (mol/mol CO2 concentrations, control chamber and on open site (ambient ...One-year-old seedlings of Pinus koraiensis, Pinus sylvestriformis, Phellodendron amurense were grown in open-top chambers (OTCs) with 700 and 500 (mol/mol CO2 concentrations, control chamber and on open site (ambient CO2, about 350 (mol/mol CO2) respectively at the Open Research Station of Changbai Mountain Forest Ecosystems, Chinese Academy of Sciences, and the growth course responses of three species to elevated CO2 and temperature during one growing season was studied from May to Oct. 1999. The results showed that increase in CO2 concentration enhanced the growth of seedlings and the effect of 700 (mol/mol CO2 was more remarkable than 500 (mol/mol CO2 on seedling growth. Under the condition of doubly elevated CO2 concentration, the biomass increased by 38% in average for coniferous seedlings and 60% for broad-leaved seedlings. With continuous treatment of high CO2 concentration, the monthly-accumulated biomass of shade-tolerant Pinus koraiensis seedlings was bigger in July than in August and September, while those of Pinus sylvestriformis and Phellodendron amurense seedlings showed an increase in July and August, or did not decrese until September. During the hot August, high CO2 concentration enhanced the growth of Pinus koraiensis seedlings by increasing temperature, but it did not show dominance in other two species.展开更多
The purpose of the current study was to investigate the eco-physiological responses,in terms of growth and C:N:P stoichiometry of plants cultured from dimorphic seeds of a single-cell C4 annual Suaeda aralocaspica(Bun...The purpose of the current study was to investigate the eco-physiological responses,in terms of growth and C:N:P stoichiometry of plants cultured from dimorphic seeds of a single-cell C4 annual Suaeda aralocaspica(Bunge)Freitag and Schütze under elevated CO_(2).A climatic chamber experiment was conducted to examine the effects of ambient(720μg/L)and CO_(2)-enriched(1440μg/L)treatments on these responses in S.aralocaspica at vegetative and reproductive stages in 2012.Result showed that elevated CO_(2) significantly increased shoot dry weight,but decreased N:P ratio at both growth stages.Plants grown from dimorphic seeds did not exhibit significant differences in growth and C:N:P stoichiometric characteristics.The transition from vegetation to reproductive stage significantly increased shoot:root ratio,N and P contents,but decreased C:N,C:P and N:P ratios,and did not affect shoot dry weight.Moreover,our results indicate that the changes in N:P and C:N ratios between ambient and elevated CO_(2) are mainly caused by the decrease of N content under elevated CO_(2).These results provide an insight into nutritional metabolism of single-cell C4 plants under climate change.展开更多
Elevated levels of atmospheric CO_(2)(eCO_(2))promote rice growth and increase methane(CH_(4))emissions from rice paddies,because increased input of plant photosynthate to soil stimulates methanogenic archae.However,t...Elevated levels of atmospheric CO_(2)(eCO_(2))promote rice growth and increase methane(CH_(4))emissions from rice paddies,because increased input of plant photosynthate to soil stimulates methanogenic archae.However,temporal trends in the effects of eCO_(2)on rice growth and CH_(4)emissions are still unclear.To investigate changes in the effects of eCO_(2)over time,we conducted a two-season pot experiment in a walk-in growth chamber.Positive effects of eCO_(2)on rice leaf photosynthetic rate,biomass,and grain yield were similar between growing seasons.However,the effects of eCO_(2)on CH_(4) emissions decreased over time.Elevated CO_(2)increased CH_(4)emissions by 48%-101%in the first growing season,but only by 28%-30%in the second growing season.We also identified the microbial process underlying the acclimation of CH4 emissions to atmospheric CO_(2)enrichment:eCO_(2)stimulated the abundance of methanotrophs more strongly in soils that had been previously exposed to eCO_(2)than in soils that had not been.These results emphasize the need for long-term eCO_(2)experiments for accurate predictions of terrestrial feedbacks.展开更多
Antibiotic resistance genes(ARGs)as new pollutants have become a global environmental pollution problem in recent years.Elevated atmospheric CO_(2) is one of the major factors affecting global climate change.But,the i...Antibiotic resistance genes(ARGs)as new pollutants have become a global environmental pollution problem in recent years.Elevated atmospheric CO_(2) is one of the major factors affecting global climate change.But,the impacts of elevated CO_(2) on soil ARGs in multiple antibiotics-contaminated paddy soils are largely unknown.In this study,six antibiotics including sulfadiazine(SDZ),sulfamethoxazole(SMZ),tetracycline(TC),oxytetracycline(OTC),enrofloxacin(ENR),and ciprofloxacin(CIP)were selected to investigate their combined effects on rice biomass,antibiotics accumulation,soil bacterial community and ARGs under elevated CO_(2) levels.Results showed that elevated CO_(2) significantly reduced the accumulation of SMZ,OTC,ENR,and CIP in rice grains by 18.98%,20.07%,41.73%,and 44.25%,respectively.Elevated CO_(2) could affect soil microbialβ-diversity,and tend to reduce the microbial functions of human diseases,organismal systems,and genetic information processing.In addition,elevated CO_(2) significantly decreased the abundance of sulfonamide ARGs,tetracycline ARGs,and quinolone ARGs by 19.59%,18.58%,and 28.96%,respectively,while increased that of multidrug ARGs by 11.54%.Overall,this study emphasized that elevated CO_(2) may mitigate the threat of antibiotics contamination to rice food security but aggravate the environmental risk of multidrug ARGs in soil,contributing to a better understanding of the consequences of elevated CO_(2) levels on food security and soil ecological health in multiple antibiotics-contaminated paddy fields.展开更多
Aims Leaf traits of trees exposed to elevated[CO_(2)]in association with other environmental factors are poorly understood in tropical and subtropical regions.Our goal was to investigate the impacts of elevated[CO_(2)...Aims Leaf traits of trees exposed to elevated[CO_(2)]in association with other environmental factors are poorly understood in tropical and subtropical regions.Our goal was to investigate the impacts of elevated[CO_(2)]and N fertilization on leaf traits in southern China.Methods Four tree species,Schima superba Gardn.et Champ.(S.superba),Ormosia pinnata(Lour.)Merr(O.pinnata),Castanopsis hystrix AC.DC.(C.hystrix)and Acmena acuminatissima(Blume)Merr.et Perry(A.acuminatissima)were studied in a factorial combination of atmospheric[CO_(2)](ambient at~390μmol mol^( -1)and elevated[CO_(2)]at~700μmol mol ^(-1))and N fertilization(ambient and ambient+100 kg N ha ^(-1)year^( -1))in open-top chambers in southern China for 5 years.Leaf mass per unit leaf area(LMA),leaf nutrient concentration and photosynthesis(A_(sat))were measured.Important Findings Results indicated that leaf traits and photosynthesis were affected differently by elevated[CO_(2)]and N fertilization among species.Elevated[CO_(2)]decreased LMA in all species,while N fertilization did not affect LMA.Leaf mass-based N concentration(N_(M))was significantly greater in O.pinnata and C.hystrix grown in elevated[CO_(2)]but was lower in S.superba.Leaf mass-based P concentration(P_(M))was significantly greater in C.hystrix and A.acuminatissima exposed to elevated[CO_(2)]but was lower in S.superba.N fertilization significantly increased P_(M) in O.pinnata but decreased P_(M) in S.superba.Photosynthetic stimulation in O.pinnata,C.hystrix and A.acuminatissima was sustained after 5 years of CO_(2)fumigation.N fertilization did not modify the effects of elevated[CO_(2)]on photosynthesis.Leaf traits(N_(M),N_(A),P_(M),P_(A))and light-saturated photosynthesis were decreased from the upper to lower canopy.Canopy position did not alter the responses of leaf traits and photosynthesis to elevated[CO_(2)].Results suggest that photosynthetic stimulation by elevated[CO_(2)]in native species in subtropical regions may be sustained in the long term.展开更多
Background:Elevated atmospheric CO_(2) has direct and indirect influences on ecosystem processes.The impact of elevated atmospheric CO_(2) concentration on carbon and nitrogen transformations,together with the microbi...Background:Elevated atmospheric CO_(2) has direct and indirect influences on ecosystem processes.The impact of elevated atmospheric CO_(2) concentration on carbon and nitrogen transformations,together with the microbial community,was evaluated with water hyacinth(Eichhornia crassipes)in an open-top chamber replicated wetland.The responses of nitrogen and carbon pools in water and wetland soil,and microbial community abundance were studied under ambient CO_(2) and elevated CO_(2)(ambient+200μL L^(−1)).Results:Total biomass for the whole plant under elevated CO_(2) increased by an average of 8%(p=0.022).Wetlands,with water hyacinth,showed a significant increase in total carbon and total organic carbon in water by 7%(p=0.001)and 21%(p=0.001),respectively,under elevated CO_(2) compared to that of ambient CO_(2).Increase in dissolved carbon in water correlates with the presence of wetland plants since the water hyacinth can directly exchange CO_(2) from the atmosphere to water by the upper epidermis of leaves.Also,the enrichment CO_(2) showed an increase in total carbon and total organic carbon concentration in wetland soil by 3%(p=0.344)and 6%(p=0.008),respectively.The total nitrogen content in water increased by 26%(p=0.0001),while total nitrogen in wetland soil pool under CO_(2) enrichment decreased by 9%(p=0.011)due to increased soil microbial community abundance,extracted by phospholipid fatty acids,which was 25%larger in amount than that of the ambient treatment.Conclusion:The study revealed that the elevated CO_(2) would affect the carbon and nitrogen transformations in wetland plant,water,and soil pool and increase soil microbial community abundance.展开更多
The inevitable rise of atmospheric CO_(2) concentration plays an important role in regulating the carbon(C)and nitrogen(N)cycling in the rice-cropping system.Elucidating the effects of elevated CO_(2) concentration(EC...The inevitable rise of atmospheric CO_(2) concentration plays an important role in regulating the carbon(C)and nitrogen(N)cycling in the rice-cropping system.Elucidating the effects of elevated CO_(2) concentration(ECO_(2))on CH_(4) and N_(2)O emissions from paddy fields is essential for evaluating agricultural production in response to global climate change.In this study,we conducted a global meta-analysis to assess the overall effect of ECO_(2) on CH_(4) and N_(2)O emissions from paddy fields,aiming at providing a guideline for sustainable C and N management in paddy fields under future climate conditions.The results showed that,overall,ECO_(2) significantly increased CH_(4) emissions from rice fields by 23%(P<0.05),but reduced N_(2)O emissions by 22%(P<0.05).With a long duration(>10 yr)of ECO_(2) ,ECO_(2) significantly reduced CH_(4) and N_(2)O emissions from paddy fields by 27%and 53%,respectively(P<0.05).Along with the increasing levels of ECO_(2) ,the stimulating effect of ECO_(2) on CH_(4) emissions showed a trend of"weakening firstly and then strengthening",while its effect on N_(2)O emissions changed from stimulation to inhibition.Agronomy managements(e.g.,N application rates,straw incorporations,water regimes,and rice cultivars)affected the effects of ECO_(2) on CH_(4) and N_(2)O emissions from paddy fields.With no or half amount of straw incorporation,ECO_(2) increased CH_(4) emissions by 27% or 49%(P<0.05)from paddy fields,respectively,while non-significant effects on CH_(4) emissions from paddy fields were observed under full straw incorporation.With the increasing amount of straw incorporation,the reductions in N_(2)O emissions from paddy fields were enhanced by ECO_(2).Compared with a continuous flooding regime,intermittent irrigation weakened the promoted effect on CH_(4) emissions but stimulated the inhibited effect on N_(2)O emissions from paddy fields under ECO_(2).Therefore,under the future condition of ECO_(2),it is recommended to adopt the appropriate agricultural management measures,such as combining straw incorporation and intermittent irrigation,and optimizing N application and using rice cultivars of high-yield with lower emissions.In addition,it is necessary to conduct comprehensive studies at multiscale,with multi-factor,and by multi-method to effectively reduce the uncertainty of quantifying the response of CH_(4) and N_(2)O emissions from paddy fields to future ECO_(2) .展开更多
CO_(2)fumigation has been extensively used in greenhouses cultivation to enhance crop yield.The effects under the precise level of elevated CO_(2)(e[CO_(2)])on crop morphology,yield,and fruit quality remain largely el...CO_(2)fumigation has been extensively used in greenhouses cultivation to enhance crop yield.The effects under the precise level of elevated CO_(2)(e[CO_(2)])on crop morphology,yield,and fruit quality remain largely elusive yet.To explore the response of plant growth to the continuous RCPs(Representative Concentration Pathways)projected CO_(2)concentration[CO_(2)],tomato(Hezuo 908)plants were grown under ambient CO_(2)(a[CO_(2)],462μmol/mol)and e[CO_(2)](550,700,850 and 1000μmol/mol):named as EC550,EC_(700),EC_(850),and EC_(1000),respectively,under uniform environmental condition for two planting seasons.Collective growth of tomato plants(plant height,stem diameter,and leaf area index)was significantly enhanced under EC_(700)and showed a slightly negative response under EC_(850).The optimum yield was stimulated under EC_(700)by 74.05%and 55.91%,while maximum total dry weight(DW_(t))was enhanced under EC_(1000)by 58.23%and 39.78%during autumn-winter and spring-summer planting seasons,respectively,as compared to a[CO_(2)].The greatest yield and least DWt stimulated under EC_(700)for both seasons indicated that EC_(700)improved the ability of the tomato plants to translocate carbohydrates to fruits.Optimum water use efficiency related to yield(WUE_(y))was enhanced by 55.91-210.87%under EC_(700)compared to a[CO_(2)].The titratable acid(TA)was improved by 19.94%(EC_(700)),29.17%(EC_(850)),and 97.92%(EC_(1000)),and the lycopene(Lp)was increased by 2.22%(EC_(700))and reduced by 2.28%(EC_(1000)).Thus,the overall optimum impact on tomato growth was explored under EC_(700).Super e[CO_(2)]did not positively influence the tomato growth process and yield under adequate water and fertilizer conditions.The present study results are beneficial for greenhouse crop production and might be used as a reference to validate the climate change influence modeling.展开更多
Global climate change and ongoing plant invasion are the two prominent ecological issues threatening biodiversity world wide.Among invasive species,Lantana camara and Hyptis suaveolens are the two most important invad...Global climate change and ongoing plant invasion are the two prominent ecological issues threatening biodiversity world wide.Among invasive species,Lantana camara and Hyptis suaveolens are the two most important invaders in the dry deciduous forest in India.We monitored the growth of these two invasive species and seedlings of four native dry deciduous species(Acacia catechu,Bauhinia variegata,Dalbergia latifolia and Tectona grandis)under ambient(375–395μmol mol^(-1))and elevated CO_(2)(700–750μmol mol^(-1))to study the differential growth response of invasive and native seedlings.Methods Seedlings of all the species were exposed to ambient and elevated CO_(2).After 60 days of exposure,seedlings were harvested and all the growth-related parameters like plant height;biomass of root,stem and leaves;total seedling biomass;R/S ratio;allocation parameters;net assimilation rate(NAR)and relative growth rate(RGR)were determined.Important Findings Biomass,RGR and NAR of all the species increased under elevated CO_(2)but the increase was higher in invasive species and they formed larger seedlings than natives.Therefore under the CO_(2)-enriched future atmosphere,competitive hierarchies could change and may interfere with the species composition of the invaded area.展开更多
Introduction:The Aspen-FACE experiment was an 11-year study of the effect of elevated CO_(2) and ozone(alone and in combination)on the growth of model aspen communities(pure aspen,aspen-birch,and aspen-maple)in the fi...Introduction:The Aspen-FACE experiment was an 11-year study of the effect of elevated CO_(2) and ozone(alone and in combination)on the growth of model aspen communities(pure aspen,aspen-birch,and aspen-maple)in the field in northern Wisconsin,USA.Uncertainty remains about how these short-term plotlevel responses might play out over broader temporal and spatial scales where climate change,competition,succession,and disturbances interact with tree-level responses.In this study,we used a new physiologybased approach(PnET-Succession v3.1)within the forest landscape model LANDIS-II to extrapolate the FACE results to broader temporal scales(and ultimately to landscape scale)by mechanistically accounting for the globally changing drivers of temperature,precipitation,CO_(2),and ozone.We added novel algorithms to the model to mechanistically simulate the effects of ozone on photosynthesis through ozone-induced impairment of stomatal control(i.e.,stomatal sluggishness)and damage of photosynthetic capacity at the chloroplast level.Results:We calibrated the model to empirical observations of competitive interactions on the elevated CO_(2) and O_(3) plots of the Aspen-FACE experiment and successfully validated it on the combined factor plots.We used the validated model to extend the Aspen-FACE experiment for 80 years.When only aspen clones competed,we found that clone 271 always dominated,although the ozone-tolerant clone was co-dominant when ozone was present.Under all treatments,when aspen clone 216 and birch competed,birch was always dominant or co-dominant,and when clone 216 and maple competed,clone 216 was dominant,although maple was able to grow steadily because of its shade tolerance.We also predicted long-term competitive outcomes for novel assemblages of taxa under each treatment and discovered that future composition and dominant taxa depend on treatment,and that short-term trends do not always persist in the long term.Conclusions:We identified the strengths and weaknesses of PnET-Succession v3.1 and conclude that it can generate potentially robust predictions of the effects of elevated CO_(2) and ozone at landscape scales because of its mechanistically motivated algorithms.These capabilities can be used to project forest dynamics under anticipated future conditions that have no historical analog with which to parameterize less mechanistic models.展开更多
Change in global climate is primarily due to rising concentrations of greenhouse gases in the atmosphere that is mostly caused by human activities.The important factors affecting the occurrence and spread of the plant...Change in global climate is primarily due to rising concentrations of greenhouse gases in the atmosphere that is mostly caused by human activities.The important factors affecting the occurrence and spread of the plant diseases are temperature,moisture,light,and CO_(2) concentration.These factors cause physiological changes in plants that result in increase in intensity of crop diseases.Climate change causes a significant impact on germination,reproduction,sporulation and spore dispersal of pathogens.Climate change affects all life stages of the pathogen as well as its host to cause impact on host-pathogen interaction which facilitates the emergence of new races of the pathogen ultimately breakdowns the host resistance.It also affects the microbial community in the soil which is beneficial to the plants in various aspects.The minor diseases become major ones due to alteration in climatic parameters thus posing a threat to the food security.展开更多
Aims Some shade-tolerant understory tree species such as mountain maple(Acer spicatum L.)exhibit light-foraging growth habits.Changes in environmental conditions,such as the rise of carbon dioxide concentration([CO_(2...Aims Some shade-tolerant understory tree species such as mountain maple(Acer spicatum L.)exhibit light-foraging growth habits.Changes in environmental conditions,such as the rise of carbon dioxide concentration([CO_(2)])in the atmosphere and soil warming,may affect the performance of these species under different light environments.We investigated how elevated[CO_(2)]and soil warm-ing influence the growth and biomass responses of mountain maple seedlings to light availability.Methods The treatments were two levels of light(100%and 30%of the ambient light in the greenhouse),two[CO_(2)](392μmol mol^(−1)(ambient)and 784μmol mol^(−1)(elevated))and two soil tempera-tures(Tsoil)(17 and 22℃).After one growing season,we measured seedling height,root collar diameter,leaf biomass,stem biomass and root biomass.Important findings We found that under the ambient[CO_(2)],the high-light level increased seedlings height by 70%and 56%at the low Tsoil and high Tsoil,respectively.Under the elevated[CO_(2)],however,the high-light level increased seedling height by 52%and 13%at the low Tsoil and high Tsoil,respectively.The responses of biomasses to light generally followed the response patterns of height growth under both[CO_(2)]and Tsoil and the magnitude of biomass response to light was the lowest under the elevated[CO_(2)]and warmer Tsoil.The results suggest that the elevated[CO_(2)]and warmer Tsoil under the projected future climate may have negative impact on the colonization of open sites and forest canopy gaps by mountain maple.展开更多
The elevated concentration of atmospheric CO_(2)may result in a decline of leaf nutritional quality(especially N)and an increase in some kinds of defensive secondary components(such as phenolics).The changes in the ph...The elevated concentration of atmospheric CO_(2)may result in a decline of leaf nutritional quality(especially N)and an increase in some kinds of defensive secondary components(such as phenolics).The changes in the phytochemistry of trees,combined with the effect of elevated CO_(2)per se,have a potential negative influence on insect herbivores.Here,we review the effect of elevated CO_(2)on the performance of leaf-feeding forest insects at individual-level and commun-ity-level.The elevated CO_(2)per se have little influence on the metabolism of insects.Over half of the tree-insect experimental systems show that the performance of individual insect become poorer under high-CO_(2)grown trees;but the others show that the insects have just little or no response to the treatments.The direction and magnitude of the changes in the performance of insects could be mediated by various factors.The effects of treatment are strongly species-dependent.The mag-nitude of changes in the phytochemistry,the sensitivity and adaptive capacity of insects to the poorer leaf quality,the differences in plant growth conditions and experimental methods,and the mediated effects of other environmental factors(such as soil nutrient availability,light,temperature,O_(3))were all closely related to the final performance of insects.However,the larvae’s consumption usually increased under enriched CO_(2)treatment,which was widely thought to be a compens-atory response to poorer plant quality.The experiments on forest community-level found identically a reduction in herbivory,which was contrary to the results from small-scale experiments.The changes in insect popu-lation and the actual response of consumption by leaf-feeding forest insects under CO_(2)enrichment remain unclear,and more field-based experiments need to be conducted.展开更多
Terrestrial net primary production(NPP)is of fundamental importance to food security and ecosystem sustainability.However,little is known about how terrestrial NPP in African ecosystems has responded to recent changes...Terrestrial net primary production(NPP)is of fundamental importance to food security and ecosystem sustainability.However,little is known about how terrestrial NPP in African ecosystems has responded to recent changes in climate and other environmental factors.Here,we used an integrated ecosystem model(the dynamic land ecosystem model;DLEM)to simulate the dynamic variations in terrestrial NPP of African ecosystems driven by climate and other environmental factors during 1980-2009.We estimate a terrestrial NPP of 10.22(minimum-maximum range of 8.9-11.3)Pg C/yr during the study period.Our results show that precipitation variability had a significant effect on terrestrial NPP,explaining 74%of interannual variations in NPP.Over the 30-yr period,African ecosystems experienced an increase in NPP of 0.03 Pg C/yr,resulting from the combined effects of climate variability,elevated atmospheric CO_(2)concentration,and nitrogen deposition.Our further analyses show that there is a difference in NPP of 1.6 Pg C/yr between wet and dry years,indicating that interannual climatic variations play an important role in determining the magnitude of terrestrial NPP.Central Africa,dominated by tropical forests,was the most productive region and accounted for 50%of the carbon sequestered as NPP in Africa.Our results indicate that warmer and wetter climatic conditions,together with elevated atmospheric CO_(2)concentration and nitrogen deposition,have resulted in a significant increase in African terrestrial NPP during 1980-2009,with the largest contribution from tropical forests.展开更多
基金the National Natural Science Foundation of China(Grant Nos.32192434,42007102)Natural Science Foundation of Fujian Province(Grant No.2020J01376)+1 种基金the Start-up Foundation for Advanced Talents in Sanming University(Grant No.19YG13)Educational Research Project for Young and Middle-aged Teachers of Fujian Provincial Department of Education(Grant No.JAT190704).
文摘Stored nonstructural carbohydrates(NSC)indicate a balance between photosynthetic carbon(C)assimilation and growth investment or loss through respiration and root exudation.They play an important role in plant function and whole-plant level C cycling.CO_(2)elevation and nitrogen(N)deposition,which are two major environmental issues worldwide,aff ect plant photosynthetic C assimilation and C release in forest ecosystems.However,information regarding the eff ect of CO_(2)elevation and N deposition on NSC storage in diff erent organs remains limited,especially regarding the trade-off between growth and NSC reserves.Therefore,here we analyzed the variations in the NSC storage in diff erent organs of Chinese fi r(Cunninghamia lanceolata)under CO_(2)elevation and N addition and found that NSC concentrations and contents in all organs of Chinese fi r saplings increased remarkably under CO_(2)elevation.However,N addition induced diff erential accumulation of NSC among various organs.Specifi cally,N addition decreased the NSC concentrations of needles,branches,stems,and fi ne roots,but increased the NSC contents of branches and coarse roots.The increase in the NSC contents of roots was more pronounced than that in the NSC content of aboveground organs under CO_(2)elevation.The role of N addition in the increase in the structural biomass of aboveground organs was greater than that in the increase in the structural biomass of roots.This result indicated that a diff erent tradeoff between growth and NSC storage occurred to alleviate resource limitations under CO_(2)elevation and N addition and highlights the importance of separating biomass into structural biomass and NSC reserves when investigating the eff ects of environmental change on biomass allocation.
基金Chinese Academy of Sciences and the Open Research Station of Changbai Mountain Forest Ecosystem.
文摘One-year-old seedlings of Pinus koraiensis, Pinus sylvestriformis, Phellodendron amurense were grown in open-top chambers (OTCs) with 700 and 500 (mol/mol CO2 concentrations, control chamber and on open site (ambient CO2, about 350 (mol/mol CO2) respectively at the Open Research Station of Changbai Mountain Forest Ecosystems, Chinese Academy of Sciences, and the growth course responses of three species to elevated CO2 and temperature during one growing season was studied from May to Oct. 1999. The results showed that increase in CO2 concentration enhanced the growth of seedlings and the effect of 700 (mol/mol CO2 was more remarkable than 500 (mol/mol CO2 on seedling growth. Under the condition of doubly elevated CO2 concentration, the biomass increased by 38% in average for coniferous seedlings and 60% for broad-leaved seedlings. With continuous treatment of high CO2 concentration, the monthly-accumulated biomass of shade-tolerant Pinus koraiensis seedlings was bigger in July than in August and September, while those of Pinus sylvestriformis and Phellodendron amurense seedlings showed an increase in July and August, or did not decrese until September. During the hot August, high CO2 concentration enhanced the growth of Pinus koraiensis seedlings by increasing temperature, but it did not show dominance in other two species.
基金This research was supported by the Strategic Priority Research Program of Chinese Academy of Sciences(XDA2003010302)the National Natural Science Foundation of China(32171514)the State Key Laboratory of Desert and Oasis Ecology,Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences(E1510107).
文摘The purpose of the current study was to investigate the eco-physiological responses,in terms of growth and C:N:P stoichiometry of plants cultured from dimorphic seeds of a single-cell C4 annual Suaeda aralocaspica(Bunge)Freitag and Schütze under elevated CO_(2).A climatic chamber experiment was conducted to examine the effects of ambient(720μg/L)and CO_(2)-enriched(1440μg/L)treatments on these responses in S.aralocaspica at vegetative and reproductive stages in 2012.Result showed that elevated CO_(2) significantly increased shoot dry weight,but decreased N:P ratio at both growth stages.Plants grown from dimorphic seeds did not exhibit significant differences in growth and C:N:P stoichiometric characteristics.The transition from vegetation to reproductive stage significantly increased shoot:root ratio,N and P contents,but decreased C:N,C:P and N:P ratios,and did not affect shoot dry weight.Moreover,our results indicate that the changes in N:P and C:N ratios between ambient and elevated CO_(2) are mainly caused by the decrease of N content under elevated CO_(2).These results provide an insight into nutritional metabolism of single-cell C4 plants under climate change.
基金supported by the National Key Research and Development Program of China(2017YFD0300104,2016YFD0300903,2015BAC02B02)the National Natural Science Foundation of China(32022061)+3 种基金the Special Fund for Agroscientific Research in the Public Interest(201503118,201503122)the Agricultural Science and Technology Innovation Program of CAAS(Y2016PT12,Y2016XT01)the Modern Agricultural Development of Jiangsu Province(2019-SJ-039-07)the GEF Project of Climate Smart Staple Crop Production in China(P144531)。
文摘Elevated levels of atmospheric CO_(2)(eCO_(2))promote rice growth and increase methane(CH_(4))emissions from rice paddies,because increased input of plant photosynthate to soil stimulates methanogenic archae.However,temporal trends in the effects of eCO_(2)on rice growth and CH_(4)emissions are still unclear.To investigate changes in the effects of eCO_(2)over time,we conducted a two-season pot experiment in a walk-in growth chamber.Positive effects of eCO_(2)on rice leaf photosynthetic rate,biomass,and grain yield were similar between growing seasons.However,the effects of eCO_(2)on CH_(4) emissions decreased over time.Elevated CO_(2)increased CH_(4)emissions by 48%-101%in the first growing season,but only by 28%-30%in the second growing season.We also identified the microbial process underlying the acclimation of CH4 emissions to atmospheric CO_(2)enrichment:eCO_(2)stimulated the abundance of methanotrophs more strongly in soils that had been previously exposed to eCO_(2)than in soils that had not been.These results emphasize the need for long-term eCO_(2)experiments for accurate predictions of terrestrial feedbacks.
基金supported by the National Natural Science Foundation of China(Nos.21876083,42177003,42107004)the Science and Technology Innovation Program of Jiangsu Province,China(No.BK20220036).
文摘Antibiotic resistance genes(ARGs)as new pollutants have become a global environmental pollution problem in recent years.Elevated atmospheric CO_(2) is one of the major factors affecting global climate change.But,the impacts of elevated CO_(2) on soil ARGs in multiple antibiotics-contaminated paddy soils are largely unknown.In this study,six antibiotics including sulfadiazine(SDZ),sulfamethoxazole(SMZ),tetracycline(TC),oxytetracycline(OTC),enrofloxacin(ENR),and ciprofloxacin(CIP)were selected to investigate their combined effects on rice biomass,antibiotics accumulation,soil bacterial community and ARGs under elevated CO_(2) levels.Results showed that elevated CO_(2) significantly reduced the accumulation of SMZ,OTC,ENR,and CIP in rice grains by 18.98%,20.07%,41.73%,and 44.25%,respectively.Elevated CO_(2) could affect soil microbialβ-diversity,and tend to reduce the microbial functions of human diseases,organismal systems,and genetic information processing.In addition,elevated CO_(2) significantly decreased the abundance of sulfonamide ARGs,tetracycline ARGs,and quinolone ARGs by 19.59%,18.58%,and 28.96%,respectively,while increased that of multidrug ARGs by 11.54%.Overall,this study emphasized that elevated CO_(2) may mitigate the threat of antibiotics contamination to rice food security but aggravate the environmental risk of multidrug ARGs in soil,contributing to a better understanding of the consequences of elevated CO_(2) levels on food security and soil ecological health in multiple antibiotics-contaminated paddy fields.
基金National Natural Science Foundation of China(31070439)the Knowledge Innovation Program of the Chinese Academy of Sciences(KSCX2-EW-Q-8)+1 种基金the National Key Technology R&D Program(2009BADC6B02)the Natural Science Foundation of Guangdong Province,China(8351065005000001).
文摘Aims Leaf traits of trees exposed to elevated[CO_(2)]in association with other environmental factors are poorly understood in tropical and subtropical regions.Our goal was to investigate the impacts of elevated[CO_(2)]and N fertilization on leaf traits in southern China.Methods Four tree species,Schima superba Gardn.et Champ.(S.superba),Ormosia pinnata(Lour.)Merr(O.pinnata),Castanopsis hystrix AC.DC.(C.hystrix)and Acmena acuminatissima(Blume)Merr.et Perry(A.acuminatissima)were studied in a factorial combination of atmospheric[CO_(2)](ambient at~390μmol mol^( -1)and elevated[CO_(2)]at~700μmol mol ^(-1))and N fertilization(ambient and ambient+100 kg N ha ^(-1)year^( -1))in open-top chambers in southern China for 5 years.Leaf mass per unit leaf area(LMA),leaf nutrient concentration and photosynthesis(A_(sat))were measured.Important Findings Results indicated that leaf traits and photosynthesis were affected differently by elevated[CO_(2)]and N fertilization among species.Elevated[CO_(2)]decreased LMA in all species,while N fertilization did not affect LMA.Leaf mass-based N concentration(N_(M))was significantly greater in O.pinnata and C.hystrix grown in elevated[CO_(2)]but was lower in S.superba.Leaf mass-based P concentration(P_(M))was significantly greater in C.hystrix and A.acuminatissima exposed to elevated[CO_(2)]but was lower in S.superba.N fertilization significantly increased P_(M) in O.pinnata but decreased P_(M) in S.superba.Photosynthetic stimulation in O.pinnata,C.hystrix and A.acuminatissima was sustained after 5 years of CO_(2)fumigation.N fertilization did not modify the effects of elevated[CO_(2)]on photosynthesis.Leaf traits(N_(M),N_(A),P_(M),P_(A))and light-saturated photosynthesis were decreased from the upper to lower canopy.Canopy position did not alter the responses of leaf traits and photosynthesis to elevated[CO_(2)].Results suggest that photosynthetic stimulation by elevated[CO_(2)]in native species in subtropical regions may be sustained in the long term.
基金The research was supported by the Natural Science Fund Project of Jilin Provincial Department of Science and Technology in 2020the Jilin Agricultural University National Undergraduate Entrepreneurship Program in 2018the Jilin Agricultural University National Undergraduate Innovation Program in 2019.
文摘Background:Elevated atmospheric CO_(2) has direct and indirect influences on ecosystem processes.The impact of elevated atmospheric CO_(2) concentration on carbon and nitrogen transformations,together with the microbial community,was evaluated with water hyacinth(Eichhornia crassipes)in an open-top chamber replicated wetland.The responses of nitrogen and carbon pools in water and wetland soil,and microbial community abundance were studied under ambient CO_(2) and elevated CO_(2)(ambient+200μL L^(−1)).Results:Total biomass for the whole plant under elevated CO_(2) increased by an average of 8%(p=0.022).Wetlands,with water hyacinth,showed a significant increase in total carbon and total organic carbon in water by 7%(p=0.001)and 21%(p=0.001),respectively,under elevated CO_(2) compared to that of ambient CO_(2).Increase in dissolved carbon in water correlates with the presence of wetland plants since the water hyacinth can directly exchange CO_(2) from the atmosphere to water by the upper epidermis of leaves.Also,the enrichment CO_(2) showed an increase in total carbon and total organic carbon concentration in wetland soil by 3%(p=0.344)and 6%(p=0.008),respectively.The total nitrogen content in water increased by 26%(p=0.0001),while total nitrogen in wetland soil pool under CO_(2) enrichment decreased by 9%(p=0.011)due to increased soil microbial community abundance,extracted by phospholipid fatty acids,which was 25%larger in amount than that of the ambient treatment.Conclusion:The study revealed that the elevated CO_(2) would affect the carbon and nitrogen transformations in wetland plant,water,and soil pool and increase soil microbial community abundance.
基金supported by the National Key Research and Development Program of China(Grant No.2017YFD0300105)the National Natural Science Foundation of China(Grant No.41877325)the project of Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2018349)。
文摘The inevitable rise of atmospheric CO_(2) concentration plays an important role in regulating the carbon(C)and nitrogen(N)cycling in the rice-cropping system.Elucidating the effects of elevated CO_(2) concentration(ECO_(2))on CH_(4) and N_(2)O emissions from paddy fields is essential for evaluating agricultural production in response to global climate change.In this study,we conducted a global meta-analysis to assess the overall effect of ECO_(2) on CH_(4) and N_(2)O emissions from paddy fields,aiming at providing a guideline for sustainable C and N management in paddy fields under future climate conditions.The results showed that,overall,ECO_(2) significantly increased CH_(4) emissions from rice fields by 23%(P<0.05),but reduced N_(2)O emissions by 22%(P<0.05).With a long duration(>10 yr)of ECO_(2) ,ECO_(2) significantly reduced CH_(4) and N_(2)O emissions from paddy fields by 27%and 53%,respectively(P<0.05).Along with the increasing levels of ECO_(2) ,the stimulating effect of ECO_(2) on CH_(4) emissions showed a trend of"weakening firstly and then strengthening",while its effect on N_(2)O emissions changed from stimulation to inhibition.Agronomy managements(e.g.,N application rates,straw incorporations,water regimes,and rice cultivars)affected the effects of ECO_(2) on CH_(4) and N_(2)O emissions from paddy fields.With no or half amount of straw incorporation,ECO_(2) increased CH_(4) emissions by 27% or 49%(P<0.05)from paddy fields,respectively,while non-significant effects on CH_(4) emissions from paddy fields were observed under full straw incorporation.With the increasing amount of straw incorporation,the reductions in N_(2)O emissions from paddy fields were enhanced by ECO_(2).Compared with a continuous flooding regime,intermittent irrigation weakened the promoted effect on CH_(4) emissions but stimulated the inhibited effect on N_(2)O emissions from paddy fields under ECO_(2).Therefore,under the future condition of ECO_(2),it is recommended to adopt the appropriate agricultural management measures,such as combining straw incorporation and intermittent irrigation,and optimizing N application and using rice cultivars of high-yield with lower emissions.In addition,it is necessary to conduct comprehensive studies at multiscale,with multi-factor,and by multi-method to effectively reduce the uncertainty of quantifying the response of CH_(4) and N_(2)O emissions from paddy fields to future ECO_(2) .
基金supported by the Natural Science Foundation of China(Grant No.51509107,51609103,41860863)Belt and Road Special Foundation of the State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering(Grant No.2020nkzd01)Postdoctoral Research of Jiangsu Province(Grant No.Bs510001),Open Fund of High-tech Key Laboratory of Agricultural Equipment and Intelligentization of Jiangsu Province and Faculty of Agricultural Equipment of Jiangsu University for financial support(Grant No.JNZ201917).
文摘CO_(2)fumigation has been extensively used in greenhouses cultivation to enhance crop yield.The effects under the precise level of elevated CO_(2)(e[CO_(2)])on crop morphology,yield,and fruit quality remain largely elusive yet.To explore the response of plant growth to the continuous RCPs(Representative Concentration Pathways)projected CO_(2)concentration[CO_(2)],tomato(Hezuo 908)plants were grown under ambient CO_(2)(a[CO_(2)],462μmol/mol)and e[CO_(2)](550,700,850 and 1000μmol/mol):named as EC550,EC_(700),EC_(850),and EC_(1000),respectively,under uniform environmental condition for two planting seasons.Collective growth of tomato plants(plant height,stem diameter,and leaf area index)was significantly enhanced under EC_(700)and showed a slightly negative response under EC_(850).The optimum yield was stimulated under EC_(700)by 74.05%and 55.91%,while maximum total dry weight(DW_(t))was enhanced under EC_(1000)by 58.23%and 39.78%during autumn-winter and spring-summer planting seasons,respectively,as compared to a[CO_(2)].The greatest yield and least DWt stimulated under EC_(700)for both seasons indicated that EC_(700)improved the ability of the tomato plants to translocate carbohydrates to fruits.Optimum water use efficiency related to yield(WUE_(y))was enhanced by 55.91-210.87%under EC_(700)compared to a[CO_(2)].The titratable acid(TA)was improved by 19.94%(EC_(700)),29.17%(EC_(850)),and 97.92%(EC_(1000)),and the lycopene(Lp)was increased by 2.22%(EC_(700))and reduced by 2.28%(EC_(1000)).Thus,the overall optimum impact on tomato growth was explored under EC_(700).Super e[CO_(2)]did not positively influence the tomato growth process and yield under adequate water and fertilizer conditions.The present study results are beneficial for greenhouse crop production and might be used as a reference to validate the climate change influence modeling.
文摘Global climate change and ongoing plant invasion are the two prominent ecological issues threatening biodiversity world wide.Among invasive species,Lantana camara and Hyptis suaveolens are the two most important invaders in the dry deciduous forest in India.We monitored the growth of these two invasive species and seedlings of four native dry deciduous species(Acacia catechu,Bauhinia variegata,Dalbergia latifolia and Tectona grandis)under ambient(375–395μmol mol^(-1))and elevated CO_(2)(700–750μmol mol^(-1))to study the differential growth response of invasive and native seedlings.Methods Seedlings of all the species were exposed to ambient and elevated CO_(2).After 60 days of exposure,seedlings were harvested and all the growth-related parameters like plant height;biomass of root,stem and leaves;total seedling biomass;R/S ratio;allocation parameters;net assimilation rate(NAR)and relative growth rate(RGR)were determined.Important Findings Biomass,RGR and NAR of all the species increased under elevated CO_(2)but the increase was higher in invasive species and they formed larger seedlings than natives.Therefore under the CO_(2)-enriched future atmosphere,competitive hierarchies could change and may interfere with the species composition of the invaded area.
基金Funding was provided by the Northern Research Station of the USDA Forest ServiceThe Aspen-FACE experiment was principally supported by the Office of Science(BER),US Department of Energy Grant No.DE-FG02-95ER62125 to Michigan Technological University+3 种基金Contract No.DE-AC02-98CH10886 to Brookhaven National LaboratoryOffice of Science(BER),US Department of Energy Interagency Agreement No.DE-AI02-09ER64717 to the US Forest Service,Northern Research Stationthe US Forest Service Northern Global Change Programthe Canadian Forest Service.
文摘Introduction:The Aspen-FACE experiment was an 11-year study of the effect of elevated CO_(2) and ozone(alone and in combination)on the growth of model aspen communities(pure aspen,aspen-birch,and aspen-maple)in the field in northern Wisconsin,USA.Uncertainty remains about how these short-term plotlevel responses might play out over broader temporal and spatial scales where climate change,competition,succession,and disturbances interact with tree-level responses.In this study,we used a new physiologybased approach(PnET-Succession v3.1)within the forest landscape model LANDIS-II to extrapolate the FACE results to broader temporal scales(and ultimately to landscape scale)by mechanistically accounting for the globally changing drivers of temperature,precipitation,CO_(2),and ozone.We added novel algorithms to the model to mechanistically simulate the effects of ozone on photosynthesis through ozone-induced impairment of stomatal control(i.e.,stomatal sluggishness)and damage of photosynthetic capacity at the chloroplast level.Results:We calibrated the model to empirical observations of competitive interactions on the elevated CO_(2) and O_(3) plots of the Aspen-FACE experiment and successfully validated it on the combined factor plots.We used the validated model to extend the Aspen-FACE experiment for 80 years.When only aspen clones competed,we found that clone 271 always dominated,although the ozone-tolerant clone was co-dominant when ozone was present.Under all treatments,when aspen clone 216 and birch competed,birch was always dominant or co-dominant,and when clone 216 and maple competed,clone 216 was dominant,although maple was able to grow steadily because of its shade tolerance.We also predicted long-term competitive outcomes for novel assemblages of taxa under each treatment and discovered that future composition and dominant taxa depend on treatment,and that short-term trends do not always persist in the long term.Conclusions:We identified the strengths and weaknesses of PnET-Succession v3.1 and conclude that it can generate potentially robust predictions of the effects of elevated CO_(2) and ozone at landscape scales because of its mechanistically motivated algorithms.These capabilities can be used to project forest dynamics under anticipated future conditions that have no historical analog with which to parameterize less mechanistic models.
文摘Change in global climate is primarily due to rising concentrations of greenhouse gases in the atmosphere that is mostly caused by human activities.The important factors affecting the occurrence and spread of the plant diseases are temperature,moisture,light,and CO_(2) concentration.These factors cause physiological changes in plants that result in increase in intensity of crop diseases.Climate change causes a significant impact on germination,reproduction,sporulation and spore dispersal of pathogens.Climate change affects all life stages of the pathogen as well as its host to cause impact on host-pathogen interaction which facilitates the emergence of new races of the pathogen ultimately breakdowns the host resistance.It also affects the microbial community in the soil which is beneficial to the plants in various aspects.The minor diseases become major ones due to alteration in climatic parameters thus posing a threat to the food security.
基金Natural Sciences and Engineering Research Council of Canada Discovery(Project#203198-2008)grant to Q.-L.D.
文摘Aims Some shade-tolerant understory tree species such as mountain maple(Acer spicatum L.)exhibit light-foraging growth habits.Changes in environmental conditions,such as the rise of carbon dioxide concentration([CO_(2)])in the atmosphere and soil warming,may affect the performance of these species under different light environments.We investigated how elevated[CO_(2)]and soil warm-ing influence the growth and biomass responses of mountain maple seedlings to light availability.Methods The treatments were two levels of light(100%and 30%of the ambient light in the greenhouse),two[CO_(2)](392μmol mol^(−1)(ambient)and 784μmol mol^(−1)(elevated))and two soil tempera-tures(Tsoil)(17 and 22℃).After one growing season,we measured seedling height,root collar diameter,leaf biomass,stem biomass and root biomass.Important findings We found that under the ambient[CO_(2)],the high-light level increased seedlings height by 70%and 56%at the low Tsoil and high Tsoil,respectively.Under the elevated[CO_(2)],however,the high-light level increased seedling height by 52%and 13%at the low Tsoil and high Tsoil,respectively.The responses of biomasses to light generally followed the response patterns of height growth under both[CO_(2)]and Tsoil and the magnitude of biomass response to light was the lowest under the elevated[CO_(2)]and warmer Tsoil.The results suggest that the elevated[CO_(2)]and warmer Tsoil under the projected future climate may have negative impact on the colonization of open sites and forest canopy gaps by mountain maple.
基金The research was supported by the National Natural Science Foundation of China(Grant No.30670306)the Knowledge Innovation Program of Chinese Academy of Sciences(No.KZCX1-SW-19)Open Foundation of Changbai Mountain Forest Ecosystem Research Station of Chinese Academy of Sciences.
文摘The elevated concentration of atmospheric CO_(2)may result in a decline of leaf nutritional quality(especially N)and an increase in some kinds of defensive secondary components(such as phenolics).The changes in the phytochemistry of trees,combined with the effect of elevated CO_(2)per se,have a potential negative influence on insect herbivores.Here,we review the effect of elevated CO_(2)on the performance of leaf-feeding forest insects at individual-level and commun-ity-level.The elevated CO_(2)per se have little influence on the metabolism of insects.Over half of the tree-insect experimental systems show that the performance of individual insect become poorer under high-CO_(2)grown trees;but the others show that the insects have just little or no response to the treatments.The direction and magnitude of the changes in the performance of insects could be mediated by various factors.The effects of treatment are strongly species-dependent.The mag-nitude of changes in the phytochemistry,the sensitivity and adaptive capacity of insects to the poorer leaf quality,the differences in plant growth conditions and experimental methods,and the mediated effects of other environmental factors(such as soil nutrient availability,light,temperature,O_(3))were all closely related to the final performance of insects.However,the larvae’s consumption usually increased under enriched CO_(2)treatment,which was widely thought to be a compens-atory response to poorer plant quality.The experiments on forest community-level found identically a reduction in herbivory,which was contrary to the results from small-scale experiments.The changes in insect popu-lation and the actual response of consumption by leaf-feeding forest insects under CO_(2)enrichment remain unclear,and more field-based experiments need to be conducted.
基金This study was partially supported by NSF Decadal and Regional Climate Prediction using Earth System Models(AGS-1243220).
文摘Terrestrial net primary production(NPP)is of fundamental importance to food security and ecosystem sustainability.However,little is known about how terrestrial NPP in African ecosystems has responded to recent changes in climate and other environmental factors.Here,we used an integrated ecosystem model(the dynamic land ecosystem model;DLEM)to simulate the dynamic variations in terrestrial NPP of African ecosystems driven by climate and other environmental factors during 1980-2009.We estimate a terrestrial NPP of 10.22(minimum-maximum range of 8.9-11.3)Pg C/yr during the study period.Our results show that precipitation variability had a significant effect on terrestrial NPP,explaining 74%of interannual variations in NPP.Over the 30-yr period,African ecosystems experienced an increase in NPP of 0.03 Pg C/yr,resulting from the combined effects of climate variability,elevated atmospheric CO_(2)concentration,and nitrogen deposition.Our further analyses show that there is a difference in NPP of 1.6 Pg C/yr between wet and dry years,indicating that interannual climatic variations play an important role in determining the magnitude of terrestrial NPP.Central Africa,dominated by tropical forests,was the most productive region and accounted for 50%of the carbon sequestered as NPP in Africa.Our results indicate that warmer and wetter climatic conditions,together with elevated atmospheric CO_(2)concentration and nitrogen deposition,have resulted in a significant increase in African terrestrial NPP during 1980-2009,with the largest contribution from tropical forests.
