What have we learned from 15 years of free-air CO2 enrichment (FACE)? A meta-analytic review of the responses of photosynthesis, canopy properties and plant production to rising CO2.

Free-air CO(2) enrichment (FACE) experiments allow study of the effects of elevated [CO(2)] on plants and ecosystems grown under natural conditions without enclosure. Data from 120 primary, peer-reviewed articles describing physiology and production in the 12 large-scale FACE experiments (475-600 ppm) were collected and summarized using meta-analytic techniques. The results confirm some results from previous chamber experiments: light-saturated carbon uptake, diurnal C assimilation, growth and above-ground production increased, while specific leaf area and stomatal conductance decreased in elevated [CO(2)]. There were differences in FACE. Trees were more responsive than herbaceous species to elevated [CO(2)]. Grain crop yields increased far less than anticipated from prior enclosure studies. The broad direction of change in photosynthesis and production in elevated [CO(2)] may be similar in FACE and enclosure studies, but there are major quantitative differences: trees were more responsive than other functional types; C(4) species showed little response; and the reduction in plant nitrogen was small and largely accounted for by decreased Rubisco. The results from this review may provide the most plausible estimates of how plants in their native environments and field-grown crops will respond to rising atmospheric [CO(2)]; but even with FACE there are limitations, which are also discussed.

[1]  A. V. Laar,et al.  Growth And Yield , 2007 .

[2]  F. Dohleman,et al.  Will photosynthesis of maize (Zea mays) in the US Corn Belt increase in future [CO2] rich atmospheres? An analysis of diurnal courses of CO2 uptake under free‐air concentration enrichment (FACE) , 2004 .

[3]  D. Ellsworth,et al.  Functional responses of plants to elevated atmospheric CO2– do photosynthetic and productivity data from FACE experiments support early predictions? , 2004 .

[4]  A. Rogers,et al.  Rising atmospheric carbon dioxide: plants FACE the future. , 2004, Annual review of plant biology.

[5]  A. Rogers,et al.  Iowa State University From the SelectedWorks of Emily Heaton April , 2004 Leaf photosynthesis and carbohydrate dynamics of soybeans grown throughout their life-cycle under Free-Air Carbon dioxide Enrichment , 2018 .

[6]  A. Rogers,et al.  Testing the “source–sink” hypothesis of down-regulation of photosynthesis in elevated [CO2] in the field with single gene substitutions in Glycine max , 2004 .

[7]  S. Long,et al.  Respiratory Oxygen Uptake Is Not Decreased by an Instantaneous Elevation of [CO2], But Is Increased with Long-Term Growth in the Field at Elevated [CO2]1 , 2004, Plant Physiology.

[8]  A. Raschi,et al.  Responses of Two Olive Tree (Olea Europaea L.) Cultivars to Elevated CO2 Concentration in the Field , 2001, Photosynthetica.

[9]  Acclimation response of spring wheat in a free-air CO2 enrichment (FACE) atmosphere with variable soil nitrogen regimes. 1. Leaf position and phenology determine acclimation response , 2000, Photosynthesis Research.

[10]  P. Pinter,et al.  Acclimation response of spring wheat in a free-air CO2 enrichment (FACE) atmosphere with variable soil nitrogen regimes. 2. Net assimilation and stomatal conductance of leaves , 2000, Photosynthesis Research.

[11]  R. Suresh Babu,et al.  Plant Responses to High CO2 Concentration in the Atmosphere , 1998, Photosynthetica.

[12]  M. Bindi,et al.  The effect of free air carbon dioxide enrichment (FACE) and soil nitrogen availability on the photosynthetic capacity of wheat , 1996, Photosynthesis Research.

[13]  S. Wullschleger,et al.  Photosynthetic acclimation in trees to rising atmospheric CO2: A broader perspective , 1994, Photosynthesis Research.

[14]  P. Morgan.  Soybean's Future: Photosynthesis, Sucrose Transport, Dry Mass Accumulation and Yield in a Changing Atmosphere , 2004 .

[15]  S. Long,et al.  Can photosynthesis respond to short-term fluctuations in atmospheric carbon dioxide? , 2004, Photosynthesis Research.

[16]  P. Pinter,et al.  Acclimation response of spring wheat in a free-air CO2 enrichment (FACE) atmosphere with variable soil nitrogen regimes. 3. Canopy architecture and gas exchange , 2004, Photosynthesis Research.

[17]  J. Nagy,et al.  Free air carbon dioxide enrichment: development, progress, results , 2004, Vegetatio.

[18]  D. Ellsworth,et al.  Leaf and canopy responses to elevated CO2 in a pine forest under free-air CO2 enrichment , 2004, Oecologia.

[19]  A. Rogers,et al.  Variation in acclimation of photosynthesis in Trifolium repens after eight years of exposure to Free Air CO2 Enrichment (FACE). , 2003, Journal of experimental botany.

[20]  S. Long,et al.  Photosynthesis and stomatal conductance responses of poplars to free-air CO2 enrichment (PopFACE) during the first growth cycle and immediately following coppice. , 2003, The New phytologist.

[21]  J. Holtum,et al.  Photosynthetic CO2 uptake in seedlings of two tropical tree species exposed to oscillating elevated concentrations of CO2 , 2003, Planta.

[22]  S. Long,et al.  How does elevated ozone impact soybean? A meta‐analysis of photosynthesis, growth and yield , 2003 .

[23]  R. Ceulemans,et al.  Three years of free‐air CO2 enrichment (POPFACE) only slightly affect profiles of light and leaf characteristics in closed canopies of Populus , 2003 .

[24]  F. I. Woodward,et al.  The importance of low atmospheric CO2 and fire in promoting the spread of grasslands and savannas , 2003 .

[25]  R. Cesar Izaurralde,et al.  Integrated assessment of Hadley Center (HadCM2) climate-change impacts on agricultural productivity and irrigation water supply in the conterminous United States: Part II. Regional agricultural production in 2030 and 2095 , 2003 .

[26]  R. Norby,et al.  Leaf dynamics of a deciduous forest canopy: no response to elevated CO2 , 2003, Oecologia.

[27]  R. E. Dickson,et al.  Tropospheric O3 moderates responses of temperate hardwood forests to elevated CO2: a synthesis of molecular to ecosystem results from the Aspen FACE project , 2003 .

[28]  Masumi Okada,et al.  Seasonal changes in the effects of elevated CO2 on rice at three levels of nitrogen supply: a free air CO2 enrichment (FACE) experiment , 2003 .

[29]  D. Karnosky,et al.  Impacts of elevated atmospheric CO(2) on forest trees and forest ecosystems: knowledge gaps. , 2003, Environment international.

[30]  M. Hovenden.  Photosynthesis of coppicing poplar clones in a free-air CO2 enrichment (FACE) experiment in a short-rotation forest. , 2003, Functional plant biology : FPB.

[31]  A. Rogers,et al.  Is stimulation of leaf photosynthesis by elevated carbon dioxide concentration maintained in the long term? A test with Lolium perenne grown for 10 years at two nitrogen fertilization levels under Free Air CO2 Enrichment (FACE) , 2003 .

[32]  R. D. Evans,et al.  Effects of elevated carbon dioxide on green leaf tissue and leaf litter quality in an intact Mojave Desert ecosystem , 2003 .

[33]  T. Huxman,et al.  Functional ecology of shrub seedlings after a natural recruitment event at the Nevada Desert FACE Facility , 2003 .

[34]  R. Ceulemans,et al.  Stem respiration of Populus species in the third year of free-air CO2 enrichment. , 2003, Physiologia plantarum.

[35]  P. Pinter,et al.  Above‐ and below‐ground responses of C3–C4 species mixtures to elevated CO2 and soil water availability , 2003 .

[36]  M. Loik,et al.  Photosynthetic responses of Mojave Desert shrubs to free air CO2 enrichment are greatest during wet years , 2003 .

[37]  R. Thomas,et al.  Leaf senescence and late-season net photosynthesis of sun and shade leaves of overstory sweetgum (Liquidambar styraciflua) grown in elevated and ambient carbon dioxide concentrations. , 2003, Tree physiology.

[38]  R. Lindroth,et al.  Responses of trembling aspen (Populus tremuloides) phytochemistry and aspen blotch leafminer (Phyllonorycter tremuloidiella) performance to elevated levels of atmospheric CO2 and O3 , 2003 .

[39]  Christopher B. Field,et al.  Grassland Responses to Global Environmental Changes Suppressed by Elevated CO2 , 2002, Science.

[40]  J. Porter,et al.  Effects of elevated CO2 and drought on wheat: testing crop simulation models for different experimental and climatic conditions , 2002 .

[41]  P. Pinter,et al.  Photosystem II energy use, non-photochemical quenching and the xanthophyll cycle in Sorghum bicolor grown under drought and free-air CO2 enrichment (FACE) conditions , 2002 .

[42]  M. Bindi,et al.  CO2 and ozone effects on canopy development of potato crops across Europe , 2002 .

[43]  S. Wullschleger,et al.  Leaf respiration at different canopy positions in sweetgum (Liquidambar styraciflua) grown in ambient and elevated concentrations of carbon dioxide in the field. , 2002, Tree physiology.

[44]  Peter S. Curtis,et al.  Plant reproduction under elevated CO2 conditions: a meta‐analysis of reports on 79 crop and wild species , 2002 .

[45]  M. Bindi,et al.  [Responses of agricultural crops of free-air CO2 enrichment]. , 2002, Ying yong sheng tai xue bao = The journal of applied ecology.

[46]  Stan D. Wullschleger,et al.  Net primary productivity of a CO2-enriched deciduous forest and the implications for carbon storage , 2002 .

[47]  E. DeLucia,et al.  Radiation-use efficiency of a forest exposed to elevated concentrations of atmospheric carbon dioxide. , 2002, Tree physiology.

[48]  G. Katul,et al.  Hydrologic balance in an intact temperate forest ecosystem under ambient and elevated atmospheric CO2 concentration , 2002 .

[49]  Effects of elevated CO2 (FACE) on the functional ecology of the drought-deciduous Mojave Desert shrub, Lycium andersonii , 2002 .

[50]  P. Curtis,et al.  A meta‐analysis of elevated [CO2] effects on soybean (Glycine max) physiology, growth and yield , 2002 .

[51]  M. Lieffering,et al.  Changes in sourcesink relations during development influence photosynthetic acclimation of rice to free air CO2 enrichment (FACE). , 2002, Functional plant biology : FPB.

[52]  D. Ellsworth,et al.  Photosynthetic acclimation of Pinus taeda (loblolly pine) to long‐term growth in elevated pCO2 (FACE) , 2002 .

[53]  R. Norby,et al.  Environmental and stomatal control of photosynthetic enhancement in the canopy of a sweetgum (Liquidambar styraciflua L.) plantation during 3 years of CO2 enrichment , 2002 .

[54]  K. Wilson,et al.  Sensitivity of stomatal and canopy conductance to elevated CO2 concentration - interacting variables and perspectives of scale. , 2002, The New phytologist.

[55]  P. Pinter,et al.  Changes in mass and energy transfer between the canopy and the atmosphere: model development and testing with a free-air CO2 enrichment (FACE) experiment , 2002, International journal of biometeorology.

[56]  R. Tognetti,et al.  Genotypic differences in the response to elevated CO2 concentration of one-year-old olive cuttings (Olea europaea L. cv. Frantoio and Moraiolo) , 2002 .

[57]  R. Ceulemans,et al.  Crown architecture of Populus spp. is differentially modified by free-air CO2 enrichment (POPFACE) , 2002 .

[58]  M. Salvucci,et al.  Rubisco: structure, regulatory interactions, and possibilities for a better enzyme. , 2002, Annual review of plant biology.

[59]  J. Houghton,et al.  Climate change 2001 : the scientific basis , 2001 .

[60]  R. Lindroth,et al.  Effects of elevated carbon dioxide and ozone on the phytochemistry of aspen and performance of an herbivore , 2002, Oecologia.

[61]  J. Isebrands,et al.  Photosynthesis, light and nitrogen relationships in a young deciduous forest canopy under open‐air CO2 enrichment , 2001 .

[62]  G. Wall,et al.  Elevated atmospheric CO2 alleviates drought stress in wheat , 2001 .

[63]  Growth performance of Populus exposed to "Free Air Carbon dioxide Enrichment" during the first growing season in the POPFACE experiment. , 2001 .

[64]  R. Ceulemans,et al.  Increased leaf area expansion of hybrid poplar in elevated CO2. From controlled environments to open-top chambers and to FACE. , 2001, Environmental pollution.

[65]  R. Ceulemans,et al.  The likely impact of rising atmospheric CO2 on natural and managed Populus: a literature review. , 2001, Environmental Pollution.

[66]  J. Bockheim,et al.  Consequences of elevated carbon dioxide and ozone for foliar chemical composition and dynamics in trembling aspen (Populus tremuloides) and paper birch (Betula papyrifera). , 2001, Environmental pollution.

[67]  E. P. McDonald,et al.  Growth responses of Populus tremuloides clones to interacting elevated carbon dioxide and tropospheric ozone. , 2001, Environmental pollution.

[68]  A. Noormets,et al.  Effects of elevated CO2 and O3 on aspen clones varying in O3 sensitivity: can CO2 ameliorate the harmful effects of O3? , 2001, Environmental pollution.

[69]  S. Jahnke.  Atmospheric CO2 concentration does not directly affect leaf respiration in bean or poplar , 2001 .

[70]  P. Pinter,et al.  Elevated atmospheric CO2 improved Sorghum plant water status by ameliorating the adverse effects of drought , 2001 .

[71]  B. Gielen,et al.  Leaf area dynamics in a closed poplar plantation under free-air carbon dioxide enrichment. , 2001, Tree physiology.

[72]  S. Long,et al.  Growth in elevated CO(2) can both increase and decrease photochemistry and photoinhibition of photosynthesis in a predictable manner. Dactylis glomerata grown in two levels of nitrogen nutrition. , 2001, Plant physiology.

[73]  J. Amthor.  Effects of atmospheric CO2 concentration on wheat yield: review of results from experiments using various approaches to control CO2 concentration , 2001 .

[74]  E. DeLucia,et al.  Direct and indirect effects of elevated CO2 on leaf respiration in a forest ecosystem , 2001 .

[75]  Judea Pearl,et al.  Direct and Indirect Effects , 2001, UAI.

[76]  P. Pinter,et al.  CO2 enrichment increases water-use efficiency in sorghum , 2001 .

[77]  P. Newton,et al.  Photosynthetic responses of temperate species to free air CO2 enrichment (FACE) in a grazed New Zealand pasture , 2001 .

[78]  D. Ellsworth,et al.  Possible explanation of the disparity between the in vitro and in vivo measurements of Rubisco activity: a study in loblolly pine grown in elevated pCO2. , 2001, Journal of experimental botany.

[79]  R. E. Dickson,et al.  The effect of elevated carbon dioxide and ozone on leaf- and branch-level photosynthesis and potential plant-level carbon gain in aspen , 2001, Trees.

[80]  Kazuhiko Kobayashi,et al.  Growth and nitrogen uptake of CO2‐enriched rice under field conditions , 2001 .

[81]  P. Pinter,et al.  Reduced photorespiration and increased energy‐use efficiency in young CO2‐enriched sorghum leaves , 2001 .

[82]  P. Pinter,et al.  Elevated CO2 increases sorghum biomass under drought conditions , 2001 .

[83]  P. Newton,et al.  Seedling performance of pasture species under elevated CO2 , 2001 .

[84]  F. Miglietta,et al.  Free‐air CO2 enrichment (FACE) of a poplar plantation: the POPFACE fumigation system , 2001 .

[85]  A. Lüscher,et al.  Response of Perennial Ryegrass to Free‐Air CO2 Enrichment (FACE) Is Related to the Dynamics of Sward Structure during Regrowth , 2001 .

[86]  M. Lieffering,et al.  Free-air CO2 enrichment (FACE) using pure CO2 injection: system description , 2001 .

[87]  R. Norby,et al.  Sap velocity and canopy transpiration in a sweetgum stand exposed to free‐air CO2 enrichment (FACE) , 2001 .

[88]  P. Pinter,et al.  Carbon isotope discrimination by Sorghum bicolor under CO2 enrichment and drought , 2001 .

[89]  R. Norby,et al.  Allometric determination of tree growth in a CO2‐enriched sweetgum stand , 2001 .

[90]  J. Coleman,et al.  Leaf conductance decreased under free-air CO2 enrichment (FACE) for three perennials in the Nevada desert , 2001 .

[91]  P. Reich,et al.  Do species and functional groups differ in acquisition and use of C, N and water under varying atmospheric CO2 and N availability regimes? : a field test with 16 grassland species , 2001 .

[92]  P. Reich,et al.  Elevated CO2 and nitrogen supply alter leaf longevity of grassland species , 2001 .

[93]  P. Reich,et al.  Leaf gas exchange responses of 13 prairie grassland species to elevated CO2 and increased nitrogen supply , 2001 .

[94]  P. Reich,et al.  [Letters to nature] , 1975, Nature.

[95]  D. Ellsworth,et al.  Crown carbon gain and elevated [CO2] responses of understorey saplings with differing allometry and architecture , 2001 .

[96]  J. Morgan,et al.  Elevated CO2 enhances water relations and productivity and affects gas exchange in C3 and C4 grasses of the Colorado shortgrass steppe. , 2001 .

[97]  F. Miglietta,et al.  Leaf area is stimulated in Populus by free air CO2 enrichment (POPFACE), through increased cell expansion and production , 2001 .

[98]  M. Bindi,et al.  Free Air CO2 Enrichment (FACE) of grapevine (Vitis vinifera L.) : II. Growth and quality of grape and wine in response to elevated CO2 concentrations , 2001 .

[99]  R. E. Dickson,et al.  Stomatal and non - stomatal limitation to photosynthesis in two trembling aspen (Populus tremuloides , 2001 .

[100]  D. Whitehead,et al.  Plant growth in elevated CO2 alters mitochondrial number and chloroplast fine structure , 2001, Proceedings of the National Academy of Sciences of the United States of America.

[101]  R. Ceulemans,et al.  Stomatal conductance of forest species after long-term exposure to elevated CO2 concentration: a synthesis. , 2001, The New phytologist.

[102]  R. Thomas,et al.  No photosynthetic down‐regulation in sweetgum trees (Liquidambar styraciflua L.) after three years of CO2 enrichment at the Duke Forest FACE experiment , 2001 .

[103]  G. Kerstiens.  Meta-analysis of the interaction between shade-tolerance,light environment and growth response of woody species to elevated CO2 , 2001 .

[104]  Robert J. Scholes,et al.  The Carbon Cycle and Atmospheric Carbon Dioxide , 2001 .

[105]  Alistair Rogers,et al.  A mechanistic evaluation of photosynthetic acclimation at elevated CO2 , 2000 .

[106]  J. Coleman,et al.  Water use of two Mojave Desert shrubs under elevated CO2 , 2000 .

[107]  J. Coleman,et al.  Elevated CO2 increases productivity and invasive species success in an arid ecosystem , 2000, Nature.

[108]  A. Lüscher,et al.  Yield response of Lolium perenne swards to free air CO2 enrichment increased over six years in a high N input system on fertile soil , 2000 .

[109]  P. Pinter,et al.  Photosynthesis and conductance of spring wheat ears: field response to free‐air CO2 enrichment and limitations in water and nitrogen supply , 2000 .

[110]  L. Ziska,et al.  The growth response of C4 plants to rising atmospheric CO2 partial pressure: a reassessment , 2000 .

[111]  A. Lüscher,et al.  Direct evidence that symbiotic N2 fixation in fertile grassland is an important trait for a strong response of plants to elevated atmospheric CO2 , 2000 .

[112]  S. Long,et al.  Sucrose‐phosphate synthase responds differently to source‐sink relations and to photosynthetic rates: Lolium perenne L. growing at elevated pCO2 in the field , 2000 .

[113]  P. Pinter,et al.  Leaf nitrogen concentration of wheat subjected to elevated [CO2] and either water or N deficits , 2000 .

[114]  J. Coleman,et al.  Photosynthetic responses of Larrea tridentata to a step-increase in atmospheric CO2at the Nevada Desert FACE Facility , 2000 .

[115]  D. Ellsworth,et al.  Photosynthetic sunfleck utilization potential of understory saplings growing under elevated CO2 in FACE , 2000, Oecologia.

[116]  E. DeLucia,et al.  Photosynthetic responses to CO2 enrichment of four hardwood species in a forest understory , 2000, Oecologia.

[117]  J. Amthor.  Direct effect of elevated CO(2) on nocturnal in situ leaf respiration in nine temperate deciduous tree species is small. , 2000, Tree physiology.

[118]  R. E. Dickson,et al.  Forest atmosphere carbon transfer and storage (FACTS-II) the aspen Free-air CO2 and O3 Enrichment (FACE) project: an overview. , 2000 .

[119]  E. Singsaas,et al.  Diurnal regulation of photosynthesis in understory saplings , 2000 .

[120]  P. De Angelis,et al.  Effects of elevated (CO2) on photosynthesis in European forest species: a meta-analysis of model parameters , 1999 .

[121]  Herrick,et al.  Effects of CO2 enrichment on the photosynthetic light response of sun and shade leaves of canopy sweetgum (Liquidambar styraciflua) in a forest ecosystem. , 1999, Tree physiology.

[122]  W. Schlesinger,et al.  Separation of root respiration from total soil respiration using carbon-13 labeling during Free-Air Carbon dioxide Enrichment (FACE) , 1999 .

[123]  S. Wand,et al.  Responses of wild C4 and C3 grass (Poaceae) species to elevated atmospheric CO2 concentration: a meta‐analytic test of current theories and perceptions , 1999 .

[124]  Baker,et al.  Does free-Air carbon dioxide enrichment affect photochemical energy use by evergreen trees in different Seasons? A chlorophyll fluorescence study of mature loblolly pine , 1999, Plant physiology.

[125]  J. Coleman,et al.  Biotic, abiotic and performance aspects of the Nevada Desert Free‐Air CO2 Enrichment (FACE) Facility , 1999 .

[126]  Mark Stitt,et al.  The interaction between elevated carbon dioxide and nitrogen nutrition: the physiological and molecular background , 1999 .

[127]  L. Firbank,et al.  Effects of Free-Air CO2 Enrichment (FACE) on experimental grassland communities , 1999 .

[128]  Jessica Gurevitch,et al.  THE META‐ANALYSIS OF RESPONSE RATIOS IN EXPERIMENTAL ECOLOGY , 1999 .

[129]  Stan D. Wullschleger,et al.  Tree responses to rising CO2 in field experiments: implications for the future forest , 1999 .

[130]  Finzi,et al.  Net primary production of a forest ecosystem with experimental CO2 enrichment , 1999, Science.

[131]  D. Ellsworth.  CO2 enrichment in a maturing pine forest: are CO2 exchange and water status in the canopy affected? , 1999 .

[132]  E. DeLucia,et al.  Photosynthetic capacity of loblolly pine (Pinus taeda L.) trees during the first year of carbon dioxide enrichment in a forest ecosystem , 1999 .

[133]  J. Ward,et al.  Elevated CO2 studies: past, present and future , 1999 .

[134]  J. Nagy,et al.  A free‐air enrichment system for exposing tall forest vegetation to elevated atmospheric CO2 , 1999 .

[135]  M. Estiarte,et al.  Free‐air CO2 enrichment of wheat: leaf flavonoid concentration throughout the growth cycle , 1999 .

[136]  S. Long,et al.  Free-air Carbon Dioxide Enrichment (FACE) in Global Change Research: A Review , 1999 .

[137]  R. C. Muchow,et al.  Radiation Use Efficiency , 1999 .

[138]  A. Raschi,et al.  Responses of two Populus clones to elevated atmospheric CO2 concentration in the field. , 1999 .

[139]  J. Coleman,et al.  Photosynthetic down-regulation in Larrea tridentata exposed to elevated atmospheric CO2: Interaction with drought under glasshouse and field (FACE) exposure , 1998 .

[140]  Bryant,et al.  Acclimation of photosynthesis to elevated CO2 under low-nitrogen nutrition is affected by the capacity for assimilate utilization. Perennial ryegrass under free-Air CO2 enrichment , 1998, Plant physiology.

[141]  S. W. Roberts,et al.  A field fumigation system for elevated carbon dioxide exposure in chaparral shrubs , 1998 .

[142]  P. Pinter,et al.  Photosynthesis and conductance of spring-wheat leaves: field response to continuous free-air atmospheric CO2 enrichment , 1998 .

[143]  D. Ellsworth,et al.  Tree and forest functioning in an enriched CO2 atmosphere , 1998 .

[144]  Osborne,et al.  Does leaf position within a canopy affect acclimation of photosynthesis to elevated CO2?. Analysis Of a wheat crop under free-air co2 enrichment , 1998, Plant physiology.

[145]  G. Taylor,et al.  Biomass and compositional changes occur in chalk grassland turves exposed to elevated CO2 for two seasons in FACE , 1998 .

[146]  M. Saurer,et al.  Growth of a deciduous tree seedling community in response to elevated CO2 and nutrient supply , 1998 .

[147]  G. Taylor,et al.  Photosynthetic acclimation to elevated CO2 is modified by source:sink balance in three component species of chalk grassland swards grown in a free air carbon dioxide enrichment (FACE) experiment , 1998 .

[148]  M. Bindi,et al.  Free Air CO2 Enrichment of potato (Solanum tuberosum L.): development, growth and yield , 1998 .

[149]  Peter S. Curtis,et al.  A meta-analysis of elevated CO2 effects on woody plant mass, form, and physiology , 1998, Oecologia.

[150]  A. Lüscher,et al.  Long-term responsiveness to free air CO2 enrichment of functional types, species and genotypes of plants from fertile permanent grassland , 1997, Oecologia.

[151]  Marco Bindi,et al.  Free Air CO2 Enrichment of potato (Solanum tuberosum, L.): design and performance of the CO2‐fumigation system , 1997 .

[152]  A. Lüscher,et al.  Does nitrogen nutrition restrict the CO2 response of fertile grassland lacking legumes? , 1997, Oecologia.

[153]  I. Impens,et al.  Stomatal regulation in a changing climate: a field study using Free Air Temperature Increase (FATI) and Free Air CO2 Enrichment (FACE) , 1997 .

[154]  A. Lüscher,et al.  Source-sink relations in Lolium perenne L. as reflected by carbohydrate concentrations in leaves and pseudo-stems during regrowth in a free air carbon dioxide enrichment (FACE) experiment* , 1997 .

[155]  B. Drake,et al.  MORE EFFICIENT PLANTS: A Consequence of Rising Atmospheric CO2? , 1997, Annual review of plant physiology and plant molecular biology.

[156]  A. Lüscher,et al.  Growth response of Trifolium repens L. and Lolium perenne L. as monocultures and bi‐species mixture to free air CO2 enrichment and management , 1997 .

[157]  A. Lúscher,et al.  Stimulation of Symbiotic N2 Fixation in Trifolium repens L. under Elevated Atmospheric pCO2 in a Grassland Ecosystem , 1996, Plant physiology.

[158]  Peter S. Curtis,et al.  A meta‐analysis of leaf gas exchange and nitrogen in trees grown under elevated carbon dioxide , 1996 .

[159]  Douglas J. Hunsaker,et al.  Carbon dioxide enrichment and irrigation effects on wheat evapotranspiration and water use efficiency , 1996 .

[160]  A. Fangmeier,et al.  Effects of elevated CO2 nitrogen supply and tropospheric ozone on spring wheat. I. Growth and yield. , 1996, Environmental pollution.

[161]  P. Pinter,et al.  Productivity and water use of wheat under free‐air CO2 enrichment , 1995 .

[162]  W. Davies,et al.  Asymmetric responses of adaxial and abaxial stomata to elevated CO2: impacts on the control of gas exchange by leaves. , 1995 .

[163]  P. Pinter,et al.  Effects of free‐air CO2 enrichment on the development of the photosynthetic apparatus in wheat, as indicated by changes in leaf proteins , 1995 .

[164]  J. Amthor.  Terrestrial higher‐plant response to increasing atmospheric [CO2] in relation to the global carbon cycle , 1995 .

[165]  B. Kimball,et al.  Increased Accumulation of Carbohydrates and Decreased Photosynthetic Gene Transcript Levels in Wheat Grown at an Elevated CO2 Concentration in the Field , 1995, Plant physiology.

[166]  J. Nagy,et al.  Design and application of a free-air carbon dioxide enrichment facility , 1994 .

[167]  J. Nagy,et al.  Canopy photosynthesis and transpiration of field-grown cotton exposed to free-air CO2 enrichment (FACE) and differential irrigation , 1994 .

[168]  J. Nagy,et al.  Influence of elevated CO2 and mild water stress on nonstructural carbohydrates in field-grown cotton tissues , 1994 .

[169]  J. Nagy,et al.  Growth and yield of cotton in response to a free-air carbon dioxide enrichment (FACE) environment , 1994 .

[170]  J. Nagy,et al.  Effects of elevated CO2 and water stress on mineral concentration of cotton , 1994 .

[171]  S. Idso,et al.  Effect of free-air CO2 enrichment on the chlorophyll content of cotton leaves , 1994 .

[172]  S. Idso,et al.  Effects of free-air CO2 enrichment on the light response curve of net photosynthesis in cotton leaves , 1994 .

[173]  J. Nagy,et al.  Leaf water relations of cotton in a free-air CO2-enriched environment , 1994 .

[174]  Reinhart Ceulemans,et al.  Tansley Review No. 71 Effects of elevated atmospheric CO2on woody plants , 1994 .

[175]  G. Bowes.  Facing the Inevitable: Plants and Increasing Atmospheric CO2 , 1993 .

[176]  D. Hileman,et al.  Responses of photosynthesis and stomatal conductance to elevated carbon dioxide in field-grown cotton , 1992 .

[177]  Keith F. Lewin,et al.  Growth and yield of cotton exposed to free‐air CO2 enrichment (Face) , 1992 .

[178]  Robert J. Anderson,et al.  Evaluating cotton response to free-air carbon dioxide enrichment with canopy reflectance observations , 1992 .

[179]  D. Hendrix.  Influence of elevated CO2 on leaf starch of field‐grown cotton , 1992 .

[180]  S. Long,et al.  Photosynthetic CO2 assimilation and rising atmospheric CO2 concentrations , 1992 .

[181]  N. Baker,et al.  Crop photosynthesis : spatial and temporal determinants , 1992 .

[182]  W. Arp.  Effects of source‐sink relations on photosynthetic acclimation to elevated CO2 , 1991 .

[183]  R. Sage,et al.  A Model Describing the Regulation of Ribulose-1,5-Bisphosphate Carboxylase, Electron Transport, and Triose Phosphate Use in Response to Light Intensity and CO(2) in C(3) Plants. , 1990, Plant physiology.

[184]  F. A. Bazzaz,et al.  The Response of Natural Ecosystems to the Rising Global CO2 Levels , 1990 .

[185]  B. Acock,et al.  Crop responses to carbon dioxide doubling: a literature survey , 1986 .

[186]  S. Long.  Leaf gas exchange , 1985 .

[187]  B. Kimball.  Carbon Dioxide and Agricultural Yield: An Assemblage and Analysis of 430 Prior Observations1 , 1983 .

[188]  N. Clark,et al.  Direct Evidence , 1934 .

[189]  BOTANiCAL Gazette.  Stomatal Regulation , 1917, Botanical Gazette.