\ T <Au G things to look atuF&G0FN ~F^&9GuF&GFݸ2WV~ub&G &WFމVFV&G &W~uKLFFΣLP # tvv^&7D.j  I ()(), "', "' ANSI StandardvVvv&|hw6Lj #^&FPj wFvvRP^STOPLISTAUTHORSJOURNALSDESCRIPT^&Gx$:Q* / :X#k]#kA Press F1 for+O O+OO / /AVpz)Fr /  Saving CO2NEW-A Pre  T%n%.) / /{Ackerly, D.D.//Coleman, J.S.//Morse, S.R.//Bazzaz, F.A.CO2 and Temperature Effects on Leaf Area Production in Two Annual Plant Species Ecology1992731260-1269-Ecology. We studied leaf area production in two annual plant species, Abutilon theophrasti and Amaranthus retroflexus, under three day/night temperature regimes (18/14C, 28/22C, and 28/31C) and two concentrations of carbon dioxide (400 and 700 uL/L). The production of whole-plant leaf area during the first 30 d of growth was analyzed in terms of the leaf initiation rate, leaf expansion, individual leaf area, and, in Amaranthus, production of branch leaves. Temperature and CO2 influenced leaf area production through stem (the plastochron index), and through shifts in the relationship between whole-plant leaf area and the number of main stem nodes. In Abutilon, leaf initiation rate was highest at 38C, but area of individual leaves was greatest at 28C. Total leaf area was greatly reduced at 18C due to slow leaf initiation rates. Elevated CO2 concentration increased leaf initiation rate at 28C, resulting in an increase in whole-plant leaf area. In Amaranthus, leaf initiation rate increased with temperature, and was increased by elevated CO2 at 28C. Individual leaf area was greatest at 28C, and was increased by elevated CO2 at 28C but decreased at 38C. Branch leaf area displayed a similar response to CO2, but was greater at 38C. Overall, whole-plant leaf area was slightly increased at 38 C relative to 28C, and elevated CO2 levels resulted in increased leaf area at 28C but decreased leaf area at 38C. The effects on leaf area closely parallel rates of biomass accumulation in the same experiment, suggesting that responses of developme ntal processes to elevated CO2 and interacting factors may play an important role in mediating effects on plant growth./Abutilon theophrasti/Amaranthus retroflexus0controlled environment chambers/old field communities/leaf area development/plastochr on index/temperature\     N X > F q { Acock, B.//Acock, M.C.//Pasternak, D.Interactions of CO2 Enrichment and Temperature on Carbohydrate Production and Accumulation in Muskmelon Leaves Journal of the American Society of Horticultural Science1990115525-529-J. Amer. So c. Hort. Sci.. We examined how temperature and stage of vegetative growth affect carbohydrate production and accumulation in Cucumis melo L. 'Haogen' grown at various CO2 concentrations ([CO2]). Carbohydrate production was measured by net assimilation rate either on a leaf-area basis (NARa) or a leaf dry-weight basis (NARw); carbohydrate accumulation was measured by leaf starch plus sugar content. Twenty-four- and 35-day-old muskmelon plants were grown for 11 days in artificially lighted cabinets at day/night temperatures of 20/20 or 40/20C and at [CO2] of 300 or 1500 uL/L. NARa and NARw both increased with increasing [CO2], but the CO2 effect was smaller at low temperature, especially for plants at the later stage of vegetative growth.  NARw was a better indicator of total dry-weight gain than was NARa. Both suboptimal temperatures and CO2 enrichment caused carbohydrates to accumulate in the leaves at both stages of vegetative growth. NARw was correlated negatively with leaf starch plus sugar content. The rate of decrease in NARw with increasing leaf starch plus sugar content was significantly greater for CO2-enriched plants. Leaf starch plus sugar content >0.03 to 0.04 kg/kg of leaf residual dry weight at the end of a dark period may indicate that temperature is suboptimal for growth. Plants grown at the same temperature had higher leaf starch plus sugar content if they were CO2-enriched than if grown in ambient [CO2], suggesting that an optimal temperature for growth in ambient [CO2] may be suboptimal in elevated [CO2]./muskmelon/Cucumis melo0SPAR units/carbohydrates/temperature/growth stages/NAR/growth analysis\*k w Acock, B.//Pasternak, D.Effects of CO2 Concentration on Composition, Anatomy, and Morphology of Plants Enoch, H.Z.//Kimball, B.A. eds. Physiology, Yield and EconomicsBoca Raton, FloridaCRC Press, Inc.1986Vol.II41-52#Carbon Dioxide Enrichment of Greenhouse Crops. In summary, we can say that species differ in their response to high CO2. Plants which are using CAM are relatively unresponsive. Other plants with the C4 pathway show modest dry weight gains but large reductions in transpiration rate. Plants which only have the C3 pathway, or well-watered CAM plants which are behaving like C3 plants, exhibit modest reductions in transpiration rate and large gains in dry weight, resulting in a variety of changes in plant composition, anatomy, and morphology. We know too little to even begin dividing C3 species into response groups. However, we can describe a typical or average response as follows. All organs on the plants become heavier with roots gaining proportionally more dry weight than stems, and stems more than leaves. The additional dry matter in the root is mainly used to increase root length with very little going to increase the density of the root tissue. Additional dry matter going to the stem causes increases in its height and diameter and little increase in the density of the tissue. Additional dry matter going to the leaves causes both a small increase in leaf area and a small increase in leaf thickness. There is an increase in structural dry matter which is probably greater than can be explained by the increase in number of mesophyll cell layers, although no one has even done a definitive experiment on this. Finally, there is an increase in starch accumulating in the leaves which, depending on the circumstances, can be very large. Branch and tiller numbers are frequently increased, as are the number of flowers. Either the weight or number of individual fruits is increased.0allocation/C3/C4/review\QBazzaz, F.A.//Garbutt, K.//Williams, W.E. In Strain, B.R.//Cure, J.D. eds. Effect of Increased Atmospheric Carbon Dioxide Concentration on Plant CommunitiesWashington, D.C.U.S. Dept. of Energy, Carbon Dioxide Research Division1985DOE/ER-0238#Direct Effects of Increasing Carbon Dioxide on Vegetation0review/community level CO2 responses/species competition/C3/C4/flowering/CO2 enrichment studies\,Arnone, J.A., IIIPhotosynthesis, Carbon Allocation, and Nitrogen Fixation in Red AlderPh.D. DissertationYale University1988(Dissertation Abstracts Vol.50:08-B, p.3244 (96 pp.). Research reported in the three sections of this dissertation addresses the problem of the effect of potentially high carbon costs of nitrogen fixation by alder-Frankia symbioses on host plant biomass productivity. Effects of root nodulation and nitrogen fixation on plant biomass productivity and al location patterns were evaluated by growing inoculated and uninoculated red alder seedlings in atmospheres containing ambient (350 uL/L) and elevated (650 uL/L) levels of CO2, with and without combined nitrogen (20 mg/L NH4NO3) supplied in modified N-!free Hoagland's nutrient solution. Effect of nodulation, CO2 enrichment, substrate nitrogen, and the feedback interaction on early seedling development and aboveground and belowground growth were also tested using the same plant material. Root:sho"ot ratios for plants in all treatments decreased over the course of the experiment. This occurred more rapidly in nodulated plants and was attributed to more rapid attainment of balanced root:shoot growth. This and evidence supporting the hypothesis# that whole plant internal carbon/nitrogen balance regulated aboveground and belowground growth is presented and discussed./Alnus rubra/red alder0nitrogen/nitrogen fixation/allocation/trees/carbon:nitrogen ratio/controlled environment chambers\Kimball, B.A.//Mauney, J.R.//Radin, J.W.//Nakayama, F.S.//Idso, S.B.//Hendrix, D.L.//Akey, D.H.//Allen, S.G.//Anderson, M.G.//Hartung, W. 039 in Green Report Series Effects of Increasing Atmospheric CO2 on the Growth, Water Relations, and% Physiology of Plants Grown under Optimal and Limiting Levels of Water and NitrogenWashington, D.C.U.S. Dept. of Energy, Carbon Dioxide Research Division, and U.S. Dept. of Agriculture, Agric. Res. Serv.1986#Response of Vegetation to Carbon Dio&xide/cotton/Gossypium hirsutum0open-top chambers/isotope discrimination/ABA/water stress/nitrogen/FIZZ irrigation/FACE/carbohydrates/leaf photosynthesis/growth/yield/water status/pink bollworm/Pectinophora gossypiella/herbivory/insects/exposure meth'ods\ Allen, L.H., Jr.Effects of Increasing Carbon Dioxide Levels and Climate Change on Plant Growth, Evapotranspiration, and Water Resources Committee on Climate Uncertainty and Water Resources Management Managing Water Resources in the West) under Conditions of Climate Uncertainty1990 Nov. 14-16Scottsdale, ArizonaWashington, D.C.National Academy Press1991101-147/soybean/Glycine max0WUE/evapotranspiration/climate change/climate model/agriculture/streamflow/GCM's/modeling/rev*iew\?Baker, J.T.//Jr., L.H. Allen,//Boote, K.J.//Jones, P.//Jones, J.W.Rice Photosynthesis and Evapotranspiration in Subambient, Ambient, and Superambient Carbon Dioxide Concentrations Agronomy Journal199082834-840-Agron. J.. The cu,rrent global rise in atmospheric carbon dioxide concentration [CO2], has stimulated interest in the response of agricultural crops to [CO2]. The objectives were to determine the effects of [CO2] on photosynthesis, evapotranspiration, and water use ef-ficiency of rice (Oryza sativa L., cv. IR-30). Rice plants were grown in naturally sunlit, plant growth chambers in subambient (160 and 250), ambient (330), or superambient (500, 660, and 900 umol CO2/mol air) [CO2] treatments. Photosynthetic light .response curves were analyzed to obtain estimates of canopy light utilization efficiency () and canopy conductance to CO2 transfer (). Estimates of increased with increasing [CO2] treatment with the greatest increase in the 160 to 500 umol/mol tr/eatments. Estimates of were more variable than those of and were not different among [CO2] treatments. Photosynthetic rates increased with increasing [CO2] treatment from 160 to 500 umol/mol followed by a leveling off of the response among the s0uperambient [CO2] treatments. Evapotranspiration decreased while water-use efficiency increased with increasing [CO2]. Short-term cross-switching of [CO2] among the chambers revealed a profound adaptive response to long-term [CO2] growth treatment. 1 The lack of further photosynthetic response above the 500 umol/mol [CO2] treatment appears to indicate a need to select or screen rice cultivars for increased response to superambient [CO2] in order to more fully take advantage of future increases in2 global atmospheric [CO2]./rice/Oryza sativa0pre-industrial CO2 concentration/canopy photosynthesis/transpiration/WUE/light/SPAR units\*  Acock, B.//Reddy, V.R.//Hodges, H.F.//Baker, D.N.//McKinion, J.M.Photosynthetic Response of Soybean Canopies to Full-Season Carbon Dioxide Enrichment Agronomy Journal198577942-947-Agron. J.. Global atmospheric CO2 concentration4 ([CO2]) is increasing as a result of the burning of fossil fuels. At present there is little information about how agronomic crops will respond to future high [CO2]. To investigate the basic process that will be most affected, soybean canopies were 5continuously exposed to various [CO2] and photosynthetic rates were measured throughout the growing season. Soybean was grown to physiological maturity in sunlit controlled-environment chambers in CO2 concentrations of 330, 450, 600 and 800 uL/L. Ca6rbon dioxide fluxes were measured on the canopies at 15-min intervals every day and used to calculate photosynthetic and respiration rates. Gross photosynthetic rate increased with each increment in [CO2] regardless of stage of development, but there7 was considerable day-to-day and seasonal variation. Seasonal changes in photosynthetic rate were associated with developmental changes in the crop. Photosynthetic rates were low during early vegetative development, even after the canopy had closed,8 but increased threefold just before flowering to reach a peak during flowering at stage R2. They then decreased by 30% or more until just before the start of pod expansion (R3) when a 45% increase occurred. Thereafter, photosynthetic rates decrease9d slowly and continuously to final harvest. The daily curves of photosynthetic rate vs. photosynthetic photon flux density were further analyzed to determine canopy light utilization efficiency () and canopy conductance to CO2 transfer (). Plants :grown in 800 uL/L [CO2] had a value of that averaged about 40% higher than that for plants grown in 330 uL/L and a value of that averaged about 24% lower for the season. Differences in between these treatments were significant throughout the se;ason, while initial differences in between treatments became less obvious after late vegetative growth stage VII./soybean/Glycine max0SPAR units/canopy photosynthesis/photosynthesis model/light utilization efficiency/conductance\*' <* Acock, B.; Jr, L.H. Allen, In Strain, B.R.//Cure, J.D. eds. Crop Responses to Elevated Carbon Dioxide ConcentrationsWashington, D.C.Dept. of Energy Carbon Dioxide Research Division1985DOE/ER-0238#Direct Effects of Increasing Ca>rbon Dioxide on Vegetation0review/photosynthesis/transpiration/WUE/environmental interactions/crop model\ Aizawa, K.//Nakamura, Y.//Miyachi, S.Variation of Phosphoenolpyruvate Carboxylase Activity in Dunaliella Associated with Changes in Atmospheric CO2 Concentration Plant Cell Physiology1985261199-1203-Plant Cell Physiol.. In Duna@liella tertiolecta, D. bioculata and D. viridis the activities of phosphoenolpyruvate carboxylase and carbonic anhydrase were higher in the cells grown in ordinary air (low-CO2 cells) than in those grown in air enriched with 1-5% CO2 (high-CO2 cells),A whereas in Porphyridium cruentum R-1 there was no difference in phosphoenolpyruvate carboxylase activity between these two types of cells. Apparent Km (NaHCO3) values for photosynthesis in low-CO2 cells of all species tested were smaller than those iBn high-CO2 cells. Most of the 14C was incorporated into 3-phosphoglycerate, sugar mono- and di-phosphates during the initial periods of photosynthetic NaH14CO3-fixation, indicating that both types of cells in D. tertiolecta are C3 plants./DunaliellaC tertiolecta/Dunaliella bioculata/Dunaliella viridis/Porphyridium cruentum0enzymes/carbonic anhydrase/phosphoenolpyruvate carboxylase/cell culture/algae/aquatic plants\ _ i   D         Akey, D.H.//Kimball, B.AGrowth and Development of the Beet Armyworm on Cotton Grown in an Enriched Carbon Dioxide Atmosphere Southwestern Entomologist198914255-260-Southwestern Entomol.. Growth and development were studied in tFhe beet armyworm (BAW), Spodoptera exigua (Hbner), reared on cotton seedlings at high (640 uL/L) or ambient (320 uL/L) carbon dioxide (CO2) levels and at two fertilizer levels. Under high fertilization, female BAW reared on CO2 enriched seedlings weiGghed significantly less (87.3 mg) than controls (101.0 mg) and had a significantly longer developmental time (14.2 versus 12.4 days for controls). Male BAW followed the same pattern, but the differences were not statistically significant. Combined (Hmale and female) survival rates for BAW reared on CO2-enriched cotton seedlings on a high fertilizer level were 19.1 compared to 41.6% for controls; more females survived than males by a significant ratio of 2:1./cotton/Gossypium hirsutum0open-top cIhambers/Spodoptera exigua/beet armyworm/insects\*   Akey, D.H.//Kimball, B.A.//Mauney, J.R.Growth and Development of the Pink Bollworm, Pectinophora gossypiella (Lepidoptera: Gelechiidae), on Bolls of Cotton Grown in Enriched Carbon Dioxide Atmospheres Environmental Entomology198817K452-455-Environ. Entomol.. The pink bollworm, Pectinophora gossypiella (Saunders), was reared on the bolls of cotton plants grown in CO2-enriched (649 uL/L) and ambient (371 uL/L) chambers and in two open field plots, one with free-air CO2 enrichmeLnt (522 uL/L) and one without enrichment (ambient CO2, 360 uL/L). The effects of increased CO2 levels on growth and development were examined. There was no difference in pupal weights of pink bollworm raised on CO2-enriched cotton compared with thoseM raised on ambient CO2 cotton (26.80 versus 26.64 mg, respectively). Also, there was no difference in developmental time (21-27 d). Analysis of percent seed damage by larvae showed no differences between CO2-enriched and ambient CO2 cotton. These rNesults were attributed to the nutritional qualities of the seed remaining the same (specifically the carbon:nitrogen ratio) despite CO2 and photosynthetic changes in the plant./cotton/Gossypium hirsutum0Pectinophora gossypiella Saunders/pink bollworOm/insects/seeds/carbon:nitrogen ratio/seed damage/open-top chambers\RT m  4 Allen, L.H., JrPlant Responses to Rising Carbon Dioxide and Potential Interactions with Air Pollutants Journal of Environmental Quality19901915-34-J. Environ. Qual.. As global population increases and industrialization expands,Q carbon dioxide (CO2) and toxic air pollutants can be expected to be injected into the atmosphere at increasing rates. This analysis reviews a wide range of direct plant responses to rising CO2, increasing levels of gaseous pollutants, and climate chRange, and potential interactions among the factors. Although several environmental interactions on stomata and foliage temperatures are reviewed briefly, a comprehensive review of effects of potential climatic change on plants is not a major objectivSe of this analysis. Research shows that elevated CO2 increases photosynthetic rates, leaf area, biomass, and yield. Elevated CO2 also reduces transpiration rate per unit leaf area, but not in proportion to reduction of stomatal conductance, because Tfoliage temperature tends to rise. With increasing leaf area and foliage temperature, water use per unit land area is scarcely reduced by elevated CO2. Increases in photosynthetic water-use efficiency are caused primarily by increased photosynthesisU rather than reduced transpiration. Gaseous pollutants (O3, SO2, NOx, H2S) affect plants adversely primarily by entry through the stomata. An example calculation showed that reduction in stomatal conductance by doubled CO2 could potentially reduce tVhe effects of ambient O3 and SO2 by 15%. However, information on the interaction of CO2 and air pollutants is scanty. More research is needed on these interactions, because regional changes in air pollutants are occurring concurrently with global chWanges in CO2.0climate change/air pollution/conductance/transpiration/WUE/review\ (Andre, M.//Du Cloux, H.//Richaud, C.Wheat Response to CO2 Enrichment: CO2 Exchanges, Transpiration and Mineral Uptakes MacElroy, R.//Martello, N.V.//Smernoff, D. eds. Controlled Ecological Life Support System: CELLS '85 Workshop1985 YJuly 16-19AMES Research Center, Moffett FieldNASA Report TM882151986405-428/wheat/Triticum aestivum0growth analysis/canopy photosynthesis/transpiration/WUE/water stress/ nutrition/plant density/phosphorus/nitrogen/potassium/controlled enviroZnment chambers\Allen, L.H., Jr.//Bisbal, E.C.//Boote, K.J.//Jones, P.H.Soybean Dry Matter Allocation under Subambient and Superambient Levels of Carbon Dioxide Agronomy Journal199183875-883-Agron. J.. Rising atmospheric carbon dioxide concent\ration [CO2] is expected to cause increases in crop growth and yield. The objective of this study was to investigate effects of subambient, as well as superambient, [CO2] on soybean [Glycine max (L.) Merr.] dry matter production and allocation for tw]o reasons: to assess response of plants to prehistoric as well as future expected CO2 levels and to increase confidence in [CO2] response curves by imposing a wide range of [CO2] treatments. Soybean was grown in outdoor, sunlit, controlled-environmen^t chambers at CO2 levels of 160, 220, 280, 330, 660, and 990 umol (CO2)/mol (air). Total dry matter growth rates during the linear phase of vegetative growth were 5.0, 8.4, 10.9, 12.5, 18.2, and 20.7 g/m2/d for the above respective [CO2]. Samples ta_ken from 24 to 94 d after planting showed that the percentage of total plant mass in leaf trifoliates decreased with increasing [CO2] whereas the percentage in structural components (petioles and stems) increased. At final harvest the respective [CO2`] treatments resulted in 38, 53, 62, 100, 120 and 92% seed yield with respect to the 330 umol/mol treatment. Total dry weight responses were similar. Late season spider mite damage of the 990 and 280 umol/mol treatments reduced yields. These data caonfirm not only that rising CO2 should increase plant growth, but also that plant growth was probably seriously limited by atmospheric [CO2] in preindustrial revolution times back to the previous global glaciation./soybean/Glycine max0SPAR units/preb-industrial CO2 concentration/allocation/yield/growth\*  Allen, L.H., Jr.//Boote, K.J.//Jones, J.W.//Jones, P.H.//Valle, R.R.//Acock, B.//Rogers, H.H.//Dahlman, R.C.Response of Vegetation to Rising Carbon Dioxide: Photosynthesis, Biomass, and Seed Yield of Soybean Global Biogeochemical Cyclesd1987I1-14-Global Biogeochem. Cycles. Elevated carbon dioxide throughout the lifespan of soybean causes an increase in photosynthesis, biomass, and seed yield. A rectangular hyperbola model predicts a 32% increase in soybean seed yield with ae doubling of carbon dioxide from 315 to 630 ppm and shows that yields may have increased by 13% from about 1800 A.D. to the present due to global carbon dioxide increases. Several other sets of data indicate that photosynthetic and growth response tof rising carbon dioxide of many species, including woody plants, is similar to that of soybean. Calculations suggest that enough carbon could be sequestered annually from increased photosynthesis and biomass production due to the rise in atmospheric cgarbon dioxide from 315 ppm in 1958 to about 345 ppm in 1986 to reduce the impact of deforestation in the tropics on the putative current flux of carbon from the biosphere to the atmosphere./soybean/Glycine max0review/growth model/pre-industrial CO2 hconcentration/carbon cycle/carbon sequestering/deforestation\Allen, L.H., Jr.//Bisbal, E.C.//Campbell, W.J.//Boote, K.J.Carbon Dioxide Effects on Soybean Developmental Stages and Expansive Growth Soil and Crop Science Society of Florida, Proceedings199049124-131-Soil and Crop Sci. Soc. Fla.j Proc.. Crop productivity is expected to increase as atmospheric carbon dioxide (CO2) continues to rise. The purpose of this paper is to examine the response of soybean [Glycine max (L.) Merr., cv. Bragg] stages of development and plant size to COk2 concentration during four experiments (1981-1984) in outdoor controlled-environment chambers. Attached lysimeters contained Arredondo fine sand (loamy, siliceous, hyperthermic Grossarenic Paleudult). Air temperature and dewpoint temperature were clontrolled to common set-points within each year with CO2 concentration being the treatment variable among chambers. Vegetative and reproductive developmental stages were determined at frequent intervals during each experiment. Growth parameters of mmainstem height, total mainstem plus branch stem length, number of mainstem nodes with branches, mainstem diameter, and leaf areas were measured during at least one experiment. Vegetative stages progressed slightly faster and the final number of nodesn was slightly greater with increased CO2 concentration. All size parameters clearly increased with increasing CO2 concentration. Growth responses per unit CO2 concentration change were greater over the subambient range (160 to 330 umol/mol) than oveor the superambient range (330 to 990 umol/mol). For soybean, plant expansive growth will increase as atmospheric CO2 continues to rise, whereas direct effects of CO2 (without interaction of potential climatic changes) will have little effect on phenoplogy./soybean/Glycine max0SPAR units/phenology/growth/pre-industrial CO2 concentration\*  Allen, L.H., Jr.//Boote, K.J.Vegetation, Effect of Rising CO2New YorkAcademic Press, Inc.1992Vol. 4409-416#Encyclopedia of Earth System Science0review/transpiration/temperature/air pollution/nutrition/climate\Allen, L.H., Jr.//Valle, R.R.//Mishoe, J.W.//Jones, J.W.//Jones, P.H.Soybean Leaf Gas Exchange Responses to CO2 Enrichment Soil and Crop Science Society of Florida, Proceedings199049192-198-Soil and Crop Sci. Soc. Fla. Proc.. Casrbon dioxide concentration of the atmosphere is expected to double within the next century. This study was undertaken to determine the leaf gas exchange responses of soybean (Glycine Max (L.) Merr. cv. Bragg) grown continuously at 330, 450, 600, and t800 L (CO2)/million L (air), or volume parts per million volumes (vpm), in sunlit, controlled-environment chambers. The chambers were secured to soil bins filled with a reconstructed profile of Arredondo fine sand (a loamy siliceous hyperthermic Grosusarenic Paleudult). A gas exchange system was used to measure leaf and air temperatures, flow rates, cuvette input and exit CO2 concentrations and vapor pressures, and incident solar photosynthetically active radiation (PAR). These measurements werev used to calculate the carbon dioxide exchange rate (CER), transpiration rate (TRATE), stomatal resistance (rs), and leaf internal airspace (intercellular) CO2 concentration (Ci) of fully expanded, sunlit leaves held in a flat, horizontal position. Rwesults indicated that leaf CER increased linearly over the CO2 concentration range of 330 to 800 vpm. Differences in leaf transpiration rates between the 800 and 330 vpm CO2 treatment were small. Water-use efficiency, CER/TRATE, increased as CO2 levexl increased, mainly due to an increase in CER. Both leaf stomatal resistance and leaf temperature increased with increasing CO2 concentrations at fixed PAR. The ratio of Ci to external CO2 concentration (Ce) was approximately constant across the ranyge of [CO2] treatments. These findings showed no tendency for CO2-saturation of soybean leaf CER (and hence no evidence of CO2-induced feedback inhibition of photosynthetic rate) over the CO2 concentration range of 330 to 800 vpm./soybean/Glycine mazx0leaf photosynthesis/transpiration/WUE/photosynthetic feedback inhibition/Ci:Ca/SPAR units/carbon/carbon\*  Allen, L.H., Jr.//Vu, J.C.V.//Valle, R.R.//Boote, K.J.//Jones, P.H.Nonstructural Carbohydrates and Nitrogen of Soybean Grown under Carbon Dioxide Enrichment Crop Science19882884-94-Crop Sci.. Carbon dioxide (CO2) concentration |has been rising in the atmosphere for over a century. This study was conducted to determine the effects of anticipated future levels of CO2 on nonstructural carbohydrates and N of soybean [Glycine max (L.) Merr. cv. Bragg]. Plants were grown at Gain}esville, FL from seed to maturity in six sunlit, controlled-environment chambers that maintained CO2 at 330, 330, 450, 600, 800, and 800 umol (CO2)/mol (air). Attached lysimeters contained Arredondo fine sand (loamy, siliceous, hyperthermic Grossare~nic Paleudult). Leaflet blades were sampled five times per day at 48 and 69 d after planting (DAP). At 48 DAP, average daytime starch conc. of leaflets increased with increasing CO2 from 85 g/kg of dry wt at 330 umol/mol to 205 g/kg at 800 umol/mol. On each date, the daytime rate of starch accumulation combined over all CO2 treatments was 6 g/kg. Specific leaf weight increased significantly throughout the day both at 48 (0.64 g/m2/h) and 69 DAP (0.29 g/m2/h). Total Kjeldahl N (TKN) conc., expressed on a g/m2 basis, showed no change over the day. Total final dry wt increased 18, 34, and 54% at 450, 600 and 800 umol/mol, respectively. The TKN harvested per plant increased 25, 26 and 45% in the 450, 600 and 800 umol/mol CO2 treatments, respectively. Plants in the 450 umol/mol CO2 treatment partitioned more biomass to seed than the other CO2 treatments. With that exception, we saw no great differences among treatment partitioning at final harvest, and thus interpret the main effect of CO2 enrichment to be enhanced photoassimilation by soybean canopies while maintaining consistent allometric relationships of the plants./soybean/Glycine max0SPAR units/carbohydrates/nitrogen/specific leaf weight/allocation\*  Allen, S.G.//Idso, S.B.//Kimball, B.A.//Anderson, M.G.Relationship between Growth Rate and Net Photosynthesis of Azolla in Ambient and Elevated CO2 Concentrations Agriculture, Ecosystems and Environment198820137-141-Agric. Ecosystems Environ.. Azolla pinnata was grown out-of-doors at Phoenix, AZ, U.S.A. in open-topped plastic-walled chambers supplied with either 340 or 640 uL CO2/L air. Net photosynthesis and growth rate were measured weekly between September 1985 and May 1986 and a significant (P<0.01) positive correlation was established between these two parameters in both CO2 environments. Regression coefficients for the linear regression of growth rate onto net photosynthesis were not significantly different in the two CO2 environments, indicating that the rate of growth per unit of CO2 uptake is not influenced by an atmospheric CO2 concentration-environment interaction./Azolla pinnata0open-top chambers/canopy photosynthesis/growth rate/aquatic plants\Rr x    Allen, S.G.//Idso, S.B.//Kimball, B.A.Interactive Effects of CO2 and Environment on Net Photosynthesis of Water-Lily Agriculture, Ecosystems and Environment19903081-88-Agric. Ecosystems Environ.. Water-lily (Nymphaea marliac) plants were grown out of doors in 570-L stock tanks contained in plastic-walled, open-topped CO2-enrichment chambers continuously supplied with either 640 or 340 (ambient) uL CO2/L air. Net photosynthesis (Pn) of water-lily leaves in each CO2 treatment was measured hourly between 0800 and 1600 h MST on 26 October and 10 and 24 November 1987. Air temperature and net solar radiation were measured at the same time. The 3 days on which Pn was measured provided an air temperature range of 10.3-33.2C and a net solar radiation range of 30-659 W/m2. Significant linear relationships were established between Pn and air temperature and Pn and net solar radiation for both CO2 treatments. Significant interactive effects of CO2 and air temperature and CO2 and net solar radiation were also found to affect Pn. In conditions generally unfavorable for Pn (low light and low temperature), there was no difference in Pn rate between the two CO2 treatments. In conditions that were favorable for Pn (high light and high temperature), however, Pn in the 640 uL CO2/L air treatment was as much as 60% greater than in the ambient CO2 treatment./Nymphaea marliac/water lily0open-top chambers/aquatic plants/canopy photosynthesis/light/temperature\*  "Amthor, J.SRespiration in a Future, Higher-CO2 World Plant, Cell and Environment19911413-20-Plant Cell Environ.. Apart from its impact on global warming, the annually increasing atmospheric [CO2] is of interest to plant scientists primarily because of its direct influence on photosynthesis and photorespiration in C3 species. But in addition, 'dark' respiration, another major component of the carbon budget of higher plants, may be affected by a change in [CO2] independent of an increase in temperature. Literature pertaining to an impact of [CO2] on respiration rate is reviewed. With an increase in [CO2], respiration rate is increased in some cases, but decreased in others. The effects of [CO2] on respiration rate may be direct or indirect. Mechanisms responsible for various observations are proposed. These proposed mechanisms relate to changes in: (1) levels of nonstructural carbohydrates, (2) growth rate and structural phytomass accumulation, (3) composition of phytomass, (4) direct chemical interactions between CO2 and respiratory enzymes, (5) direct chemical interactions between CO2 and other cellular components, (6) dark CO2 fixation rate, and (7) ethylene biosynthesis rate. Because a range of (possibly interactive) effects exists, and present knowledge is limited, the impact of future [CO2] on respiration rate cannot be predicted. Theoretical considerations and types of experiments that can lead to an increase in the understanding of this issue are outlined.0review/carbon budget/respiration\#Amthor, J.S//Koch, G.W.//Bloom, A.J.CO2 Inhibits Respiration in Leaves of Rumex crispus L. Plant Physiology199298757-760-Plant Physiol.. Curly dock (Rumex crispus L.) was grown from seed in a glasshouse at an ambient CO2 partial pressure of about 35 pascals. Apparent respiration rate (CO2 efflux in the dark) of expanded leaves was then measured at ambient CO2 partial pressure of 5 to 95 pascals. Calculated intercellular CO2 partial pressure was proportional to ambient CO2 partial pressure in these short term experiments. The CO2 level strongly affected apparent respiration rate: a doubling of the partial pressure of CO2 typically inhibited respiration by 25 to 30%, whereas a decrease in CO2 elicited a corresponding increase in respiration. These responses were readily reversible. A flexible, sensitive regulatory interaction between CO2 (a byproduct of respiration) and some component(s) of heterotrophic metabolism is indicated./Rumex crispus/curly dock0greenhouse/respiration/Ci:Ca\RK X   $Anderson, I.H.//Dons, C.//Nilsen, S.//Haugstad, M.K.Growth, Photosynthesis and Photorespiration of Lemna gibba: Response to Variations in CO2 and O2 Concentrations and Photon Flux Density Photosynthesis Research1985687-96-Photosynth. Res.. Dry weight and Relative Growth Rate of Lemna gibba were significantly increased by CO2 enrichment up to 6000 uL CO2/L. This high CO2 optimum for growth is probably due to the presence of nonfunctional stomata. The response to high CO2 was less or absent following four days growth in 2% O2. The Leaf Area Ratio decreased in response to CO2 enrichment as a result of an increase in dry weight per frond. Photosynthetic rate was increased by CO2 enrichment up to 1500 uL CO2/L during measurement, showing only small increases with further CO2 enrichment up to 5000 uL CO2/L at a photon flux density of 210 umol/m2/s and small decreases at 2000 umol/m/s. The actual rate of photosynthesis of those plants cultivated at high CO2 levels, however, was less than the air grown plants. The response of photosynthesis to O2 indicated that the enhancement of growth and photosynthesis by CO2 enrichment was a result of decreased photorespiration. Plants cultivated in low O2 produced abnormal morphological features and after a short time showed a reduction in growth./Lemna gibba/duckweed0growth/respiration/canopy photosynthesis/oxygen/light/aquatic plants/controlled environment chambers\Rd o  * &Andre, M.//Cotte, F.//Gerbaud, A.//Massimino, D.//Massimino, J.//Richaud, C.Effect of CO2 and O2 on Development and Fructification of Wheat in Closed Systems Advances in Space Research19899(8)17-(8)28-Adv. Space Res.. The cultivation of wheat (Triticum aestivum L.) was performed in controlled environment chambers with the continuous monitoring of photosynthesis, dark respiration, transpiration and main nutrient uptakes. A protocol in twin chambers was developed to compare the specific effects of low O2 and high CO2. Each parameter is able to influence photosynthesis but different effects are obtained in the development, fructification and seed production, because of the different effects of each parameter on the ratio of reductive to oxidative cycle of carbon. The first main conclusion is that low level of O2, at the same rate of biomass production, strongly acts on the rate of ear appearance and on seed production. Ear appearance was delayed and seed production reduced with a low O2 treatment (about 4%). The O2 effect was not mainly due to the repression of the oxidative cycle. The high CO2 treatment (700 to 900 uL/L) delayed ear appearance by 4 days, but did not reduce seed production. High CO2 treatment also reduced transpiration by 20%. Two hypotheses were proposed to explain the similarities and the difference in the O2 and CO2 effects on the growth of wheat./Triticum aestivum/wheat0controlled environment chambers/oxygen/seed production/canopy photosynthesis/respiration\*   'Andre, M.//Du Cloux, H.Interaction of CO2 Enrichment and Water Limitations on Photosynthesis and Water-Use Efficiency in Wheat Plant Physiology and Biochemistry199331103-112-Plant Physiol. Biochem.. Wheat plants (Triticum aestivum L. cv. Capitole) were grown in twin closed growth chambers with continuous monitoring of CO2 and water exchanges. During the vegetative stage the effect of CO2 enrichment, from 330 to 660 uL/L, was studied under an irradiance of 660 uE/m2/s with an optimum watering. Comparisons were made with successive experiments in which daily water supply was fixed to a fraction (0.62-0.5-0.25) of the maximal transpiration of previous experiments. In a well watered canopy, the doubling of CO2 decreased transpiration by only 8%. Water use efficiency was increased (factor 1.45) mainly by the stimulation of photosynthesis. Under restricted water supply, photosynthesis of plants was more limited than transpiration. The inhibition of photosynthesis and the increase of water use efficiency can be predicted by a simple diffusion model applied to the response curve of photosynthesis to CO2, measured on canopy in standard conditions of watering. The main hypothesis is that the equivalent stomatal conductance is reduced proportionally to the water availability, without closure by patching. Under enriched CO2, the same reduction of leaf surface by water limitation was observed. Photosynthesis was less affected. Therefore, water use efficiency was again increased. Doubling CO2 concentration can compensate for water stress inhibition on CO2 assimilation. That model also predicts interactions of CO2 and water stress observed on water-use-efficiency which was increased by a factor up to 5 in comparison with well-watered plants in standard atmosphere. The implications of this study on global change models are discussed./wheat/Triticum aestivum0controlled environment chambers/grasses/conductance/water stress/canopy photosynthesis/WUE/transpiration/photosynthesis model\*  )Andre, M.//Ducloux, H.//Richaud, C.//Massimino, D.//Daguenet, A.//Massimino, J.//Gerbaud, A.Etude des Relations entre Photosynthese Respiration, Transpiration et Nutrition Minerale chez le Ble Advances in Space Research19877(4)105-(4)114-Adv. Space Res.. La croissance du Ble Triticum aestivum a ete etudiee en environnement controle et ferme pendant une periode de 70 jours. Les echanges gazeux (Photosynthese, Respiration) hydriques (Transpiration) et al consommation en elements mineraux (Azote, Phosphore, Potassium) ont ete mesures en continu. On prsentera les relations dynamiques observees entre les differentes fonctions physiologiques, d'une part sous l'influence de la croissance et d'autre part en reponse a des modifications de l'environnement. L'influence de la teneur en CO2 pendant la croissance (teneur normale ou doublee) sera mise en evidence. In French./wheat/Triticum aestivum0canopy photosynthesis/respiration/transpiration/nutrition/nitrogen/potassium/phosphorus/controlled environment chambers\* . *Andreeva, T.F.//Strogonova, L.E.//Voevudskaya, S.Yu.//Maevskaya, S.N.//Cherkanova, N.N.Effect of Enhanced CO2 Concentration on Photosynthesis, Carbohydrate and Nitrogen Metabolism, and Growth Processes in Mustard Plants Fiziologiya Rastenii19893640-48-Fiziol. Rast.. We investigated prolonged (8- to 10-day) influence of enhanced carbon dioxide content (0.03-0.05%) in the air on photosynthesis of mustard plants (Brassica juncea L.), on their carbohydrate and nitrogen metabolism, and on the course of growth processes. Considerable attention is devoted to the question of the effect of leaf starch excess on the rate of photosynthesis. It is demonstrated that mustard plants in the vegetative phase of growth under conditions of enhanced CO2 concentration in the air exhibit higher pure productivity of photosynthesis and a higher rate of photosynthesis than in plants growing at normal CO2 content in the atmosphere. Increase of apparent photosynthesis is realized without supplementary synthesis of fraction I protein. Increase in the rate of photosynthesis is accompanied by intensification of nitrogen metabolism, increase of growth, and accumulation of biomass. An excess of assimilates in the form of starch accumulates in the chloroplasts (25% of leaf dry mass at 27/24). Starch content increases significantly in plants grown under conditions of reduced temperature compared with ones grown at a higher temperature (34.4% of leaf dry mass at 20/17 as compared with 20.1% at 32/27). It is concluded that high starch content in the leaves is not a cause of photosynthesis suppression. Decline of photosynthesis is observed only when the starch excess disturbs structure of the chloroplasts./mustard/Brassica juncea0photosynthesis/fraction 1 protein/carbohydrates/nitrogen/temperature/controlled environment chambers\*  +Apel, PInfluence of CO2 on Stomatal Numbers Biologia Plantarum (Praha)1989372-74-Biol. Plantarum. From nine different plant species grown at 1500 cm3/m3 CO2 five responded with a significant increase in stomatal numbers per mm2 as compared with plants grown under normal air conditions. Within a collection of twelve french bean cultivars remarkable cultivar differences with regard to the CO2 enhancement effect on stomatal numbers was found./Phaseolus vulgaris/Vicia faba/Lycopersicon esculentum/Acer pseudoplatanus/Triticum aestivum/Hordeum vulgare/Secale cereale /Avena sativa/Zea mays/bean/broad bean/tomato/sycamore maple/wheat/barley/rye/oat/corn0stomatal density/cultivar responses/controlled environment chambers\-Arnone, J.A., III//Gordon, J.C.Effect of Nodulation, Nitrogen Fixation and CO2 Enrichment on the Physiology, Growth and Dry Mass Allocation of Seedlings of Alnus rubra Bong. New Phytologist199011655-66-New Phytol.. Inoculated and uninoculated Alnus rubra Bong. seedlings were grown for 47 days in atmospheres containing ambient (350 uL CO2/L) and elevated (650 uL CO2/L) levels of CO2, with and without combined nitrogen (20 mg/L) supplied as ammonium nitrate. Five plants from each treatment were harvested 15, 30, and 47 days after exposure to CO2 treatments began. Evidence for the presence of a positive feedback loop between nitrogen fixation and photosynthesis was observed in nodulated plants growing at elevated CO2. These plants had greater whole-plant photosynthesis and nitrogenase activity, leaf area and nitrogen content, as well as nodule and plant dry mass, relative to nodulated plants grown at ambient CO2 and non-nodulated plants grown at both CO2 levels. This feedback may be an important way in which the potential carbon drain of nitrogen fixation on the host plant could be compensated; increased nitrogen availability resulting in stimulated leaf area growth and whole-plant photosynthesis. The relative amount of dry mass allocated to below ground decreased for all seedlings over time, and the amount allocated above ground increased. This shift in allocation occurred slowly and at a constant rate in non-nodulated plants and more rapidly and abruptly when plants were nodulated. The proportion of dry mass allocated below ground was consistently greater in non-nodulated plants grown at high CO2. Dry mass partitioning among other organs was not directly affected by nodulation, CO2 enrichment, or other treatment interactions./Alnus rubra0trees/nodulation/nitrogen fixation/allocation/controlled environment chambers\R    .Arp, W.JEffects of Source-Sink Relations on Photosynthetic Acclimation to Elevated CO2 Plant, Cell and Environment199114869-875-Plant Cell Environ.. While photosynthesis of C3 plants is stimulated by an increase in the atmospheric CO2 concentration, photosynthetic capacity is often reduced after long-term exposure to elevated CO2. This reduction appears to be brought about by end product inhibition, resulting from an imbalance in the supply and demand of carbohydrates. A review of the literature revealed that the reduction of photosynthetic capacity in elevated CO2 was most pronounced when the increased supply of carbohydrates was combined with small sink size. The volume of pots in which plants were grown affected the sink size by restricting root growth. While plants grown in small pots had a reduced photosynthetic capacity, plants grown in the field showed no reduction or an increase in this capacity. Pot volume also determined the effect of elevated CO2 on the root:shoot ratio--the root:shoot ratio increased when root growth was not restricted and decreased in plants grown in small pots. The data presented in this paper suggest that plants growing in the field will maintain a high photosynthetic capacity as the atmospheric CO2 level continues to rise.0review/photosynthetic acclimation/source-sink balance/root:shoot ratio/pot volume\0Arp, W.J.//Drake, B.G.Increased Photosynthetic Capacity of Scirpus olneyi after 4 Years of Exposure to Elevated CO2 Plant, Cell and Environment1991141003-1006-Plant Cell Environ.. While a short-term exposure to elevated atmospheric CO2 induces a large increase in photosynthesis in many plants, long-term growth in elevated CO2 often results in a smaller increase due to reduced photosynthetic capacity. In this study, it was shown that, for a wild C3 species growing in its natural environment and exposed to elevated CO2 for four growing seasons, the photosynthetic capacity has actually increased by 31%. An increase in photosynthetic capacity has been observed in other species growing in the field, which suggests that photosynthesis of certain field grown plants will continue to respond to elevated levels of atmospheric CO2./sedge/Scirpus olneyi0leaf photosynthesis/photosynthetic acclimation/open-top chambers\*< J 2Artus, N.N.Two Mutants of Arabidopsis thaliana That Become Chlorotic in Atmospheres Enriched with CO2 Plant, Cell and Environment199013575-580-Plant Cell Environ.. Two nonallelic, nuclear recessive mutants of Arabidopsis thaliana (L.) Heynh. which become chlorotic when grown in an atmosphere enriched to 20,000 cm3 CO2/m3 have been isolated. For one of the mutants, chlorosis begins at the veins and gradually spreads to the interveinal regions. A minimum photon flux density of ca 50 umol/m2/s is required for this response. For the other mutant, the yellowing is independent of the light intensity and begins at the basal regions of the leaves and spreads to the tips. The injurious effects of CO2 seem to be restricted to photosynthetic tissues, since root elongation and callus growth were not inhibited by a high atmospheric CO2 concentration for either mutant. Neither mutant became chlorotic in a low O2 atmosphere that suppressed photorespiration as effectively as the elevated CO2 does. Thus, the mutations do not impose a requirement for photorespiration. The possibilities that the high CO2-sensitive phenotypes are caused by an effect of CO2 in stomata, on ethylene synthesis, or on mineral uptake are discussed but are considered unlikely./Arabidopsis thaliana0mutant/controlled environment chambers\R /   4Aston, A.R.The Effect of Doubling Atmospheric CO2 on Streamflow: a Simulation Journal of Hydrology198467273-280-J. Hydrol.. There is a potential for atmospheric CO2 to rise four- or six-fold, and at some time in the foreseeable future a doubling of stomatal resistance seems, on present evidence, to be inevitable. A distributed deterministic process model was used to simulate the effects of changed stomatal resistance on stremflow of a 5-ha experimental catchment and a large (417 km2) water-supply area. The results indicated that we can expect streamflow to increase from 40 to 90% as a consequence of doubling of atmospheric CO2 concentration.0streamflow/hydrologic model\Burnett, R.B.//Chaudhuri, U.N.//Kanemasu, E.T.//Kirkham, M.B. 024 in Green Report Series Sorghum at Elevated Levels of CO2Washington, D.C.U.S. Dept. of Energy, Carbon Dioxide Research Division1985#Response of Vegetation to Carbon Dioxide/sorghum/Sorghum bicolor0rhizotron/outdoor growth chambers/growth stages/yield/evapotranspiration/C4/roots/root:shoot ratio/allocation/WUE\kBiswas, P.K.//Hileman, D.R.//Allen, J.R.//Bhattacharya, N.C.//Lu, J.Y.//Pace, R.D.//Rogers, H.H. 022 in Green Report Series Field Studies of Sweet Potatoes and Cowpeas in Response to Elevated Carbon DioxideWashington, D.C. and Tuskegee, AlabamaU.S. Dept. of Energy, Carbon Dioxide Research Division, and Tuskegee University1985#Response of Vegetation to Carbon Dioxide/sweet potato/cowpea/Ipomoea batatas/Vigna unguiculata0open-top chambers/nitrogen/conductance/growth/yield/nitrogen fixation//crops\ Acock, B.//Trent, A. 017 in Green Report Series The Soybean Crop Simulator GLYCIM: Documentation for the Modular Version 91Washington, D.CU.S. Dept. of Energy, Carbon Dioxide Research Division, and U.S. Dept. of Agriculture, Agric. Res. Serv.1991#Response of Vegetation to Carbon Dioxide/soybean/Glycine max0generic model/crop model/simulation\Acock, B.//Acock, M.C.//Reddy, V.R.//Baker, D.N. 011 in Green Report Series The Simulation, with GLYCIM, of Soybean Crops Grown in the Field and at Various CO2 Concentrations in Open-top Chambers during 1982Washington, D.C.U.S. Dept. of Energy, Carbon Dioxide Research Division, and U.S. Dept. of Agriculture, Agric. Res. Serv.1985#Response of Vegetation to Carbon Dioxide/soybean0open-top chambers/modeling/crop model/simulation\Doyle, T.W.//Taylor, F.G.//Parker, M.L.//Cooper, C.F.//West, D.C. 025 in Green Report Series Preliminary Ring-Width and Ring-Density Data for Deriving Wood Mass Chronologies of Coniferous Species from the Northwest U.S. and CanadaWashington, D.C. and Oak Ridge, TennesseeU.S. Dept. of Energy, Carbon Dioxide Research Division, and Environmental Sciences Division, Oak Ridge National Laboratory1985#Response of Vegetation to Carbon Dioxide/white spruce/red pine/Douglas-fir/Western hemlock/Western red cedar/Engelmann spruce/lodgepole pine/yellow cedar/black spruce0trees/tree-ring analysis\Graybill, D.A. 026 in Green Report Series Western U.S. Tree-Ring Index Chronology Data for Detection of Arboreal Response to Increasing Carbon DioxideWashington, D.C., and Oak Ridge, TennesseeU.S. Dept. of Energy, Carbon Dioxide Research Division, and Environmental Sciences Division, Oak Ridge National Laboratory1985#Response of Vegetation to Carbon Dioxide/Pinus longaeva/Pinus aristata/Pinus flexilis0trees/trees/tree-ring analysis/altitude\Kimball, B.A.//Mauney, J.R.//Guinn, G.//Nakayama, F.S.//Idso, S.B.//Radin, J.W.//Hendrix, D.L.//Butler, G.D.//Zarembinski, T.I.//Nixon, P.E. 027 in Green Report Series Effect of Increasing Atmospheric CO2 on the Yield and Water Use of CropsWashington, D.C.U.S. Dept. of Energy, Carbon Dioxide Research Division, and U.S. Dept. of Agriculture, Agric. Res. Serv.1985#Response of Vegetation to Carbon Dioxide/cotton/Gossypium hirsutum0open-top chambers/yield/conductance/water status/photosynthetic acclimation/leaf photosynthesis/carbohydrates/soil respiration/exposure methods\sReynolds, J.F.//Bachelet, D.//Leadley, P.//Moorhead, D. 028 in Green Report Series Assessing the Effects of Elevated Carbon Dioxide on Plants: Towards the Development of a Generic Plant Growth ModelWashington, D.C.U.S. Dept. of Energy, Carbon Dioxide Research Division1986#Response of Vegetation to Carbon Dioxide0generic model/modeling/growth model\Chaudhuri, U.N.//Burnett, R.B.//Kanemasu, E.T//Kirkham, M.B. 029 in Green Report Series Effect of Elevated Levels of CO2 on Winter Wheat under Two Moisture RegimesWashington, D.C.U.S. Dept. of Energy, Carbon Dioxide Research Division1986#Response of Vegetation to Carbon Dioxide/wheat/Triticum aestivum0rhizotron/outdoor growth chambers/water stress/WUE/yield/roots/evapotranspiration/water status/conductance\lBiswas, P.K.//Hileman, D.R.//Bhattacharya, N.C.//Ghosh, P.P.//Bhattacharya, S.//Johnson, J.H.//Mbikayi, N.T. 030 in Green Report Series Growth, Yield and Plant Water Relationships in Sweet Potatoes in Response to Carbon Dioxide EnrichmentWashington, D.C. and Tuskegee, AlabamaU.S. Dept. of Energy, Carbon Dioxide Research Division, and Tuskegee University1986#Response of Vegetation to Carbon Dioxide/sweet potato/Ipomoea batatas0open-top chambers/growth analysis/yield/water status/leaf photosynthesis/water stress\Allen, L.H., Jr.//Boote, K.J.//Jones, J.W.//Mishoe, J.W.//Jones, P.H.//Valle, R.R//Bisbal, E.C. 031 in Green Report Series Subambient and Superambient Carbon Dioxide Effects on Growth, Nonstructural Carbohydrates, Biochemistry of Photosynthesis and Transpiration of Soybeans. 1984 Progress ReportWashington, D.C.U.S. Dept. of Energy, Carbon Dioxide Research Division, and U.S. Dept. of Agriculture, Agric. Res. Serv.1985#Response of Vegetation to Carbon Dioxide/soybean/Glycine max0SPAR units/pre-industrial CO2 concentration/growth/carbohydrates/photosynthesis/transpiration/ribulose bisphosphate carboxylase\Cure, J.D.//Galloway, L.F.//Israel, D.W.//Jr., T.W. Rufty, 033 in Green Report Series Influence of Nutrition on Vegetation Response to Carbon Dioxide. I. Interactions of Nitrogen and Phosphorus Supply on Soybean Growth and Nutritional ParametersWashington, D.C.U.S. Dept. of Energy, Carbon Dioxide Research Division1986#Response of Vegetation to Carbon Dioxide/soybean/Glycine max0controlled environment chambers/nutrition/nitrogen/phosphorus/growth/yield\Drake, B.//Arp, W.//Curtis, P.S.//Leadley, P.W.//Sager, J.//Whigham, D. 034 in Green Report Series Effects of Elevated CO2 on Chesapeake Bay Wetlands. I. Description of the Study SiteWashington, D.C.U.S. Dept. of Energy, Carbon Dioxide Research Division1986#Response of Vegetation to Carbon Dioxide/Spartina patens/Distichlis spicata/Scirpus olneyi0open-top chambers/salt marsh/litter quality/water status/aquatic plants/halophytes/exposure methods\+Oechel, W.C.//Riechers, G.H.//Beyers, J.//Cowles, S.//Grulke, N.//Hastings, S.//Oberbauer, S//Prudhomme, T.//Sionit, N. 037 in Green Report Series Response of a Tundra Ecosystem to Elevated Atmospheric Carbon DioxideWashington, D.C.U.S. Dept. of Energy, Carbon Dioxide Research Division1986#Response of Vegetation to Carbon Dioxide/Vaccinium vitis-idaea/Eriophorum vaginatum/Ledum palustre/Carex bigelowii/Betula nana0tracking chambers/tundra/allocation/soil respiration/photosynthetic acclimation/leaf photosynthesis/nutrition/exposure methods\Drake, B.G.//Arp, W.//Craig, J.//Curtis, P.S.//Leadley, P.W.//Whigham, D. 038 in Green Report Series Effects of Elevated CO2 on Chesapeake Bay Wetlands. II. Gas Exchange and Microenvironment in Open Top ChambersWashington, D.C.U.S. Dept. of Energy, Carbon Dioxide Research Division1987#Response of Vegetation to Carbon Dioxide/Scirpus olneyi/Spartina patens/Distichlis spicata0open-top chambers/salt marsh/canopy photosynthesis/conductance/photosynthetic acclimation/aquatic plants/halophytes/exposure methods\Chaudhuri, U.N.//Burnett, R.B.//Kanemasu, E.T//Kirkham, M.B. 040 in Green Report Series Effect of Elevated Levels of CO2 on Winter Wheat under Two Moisture RegimesWashington, D.C.U.S. Dept. of Energy, Carbon Dioxide Research Division1987#Response of Vegetation to Carbon Dioxide/wheat/Triticum aestivum0rhizotron/water stress/roots/outdoor growth chambers/transpiration/conductance/fluorescence/allocation/carbohydrates/yield\vReynolds, J.F.//Skiles, J.W.//Moorhead, D.L. 041 in Green Report Series SERECO: A Model for the Simulation of Ecosystem Response to Elevated CO2Washington, D. C.U.S. Dept. of Energy, Carbon Dioxide Research Division1987#Response of Vegetation to Carbon Dioxide0modeling/ecosystem model/ecosystem level CO2 responses/generic model/scaling\<Baker, J.T.//Jr., L.H. Allen,//Boote, K.J.//Rowland-Bamford, A.J.//Jones, J.W.//Jones, P.H.//Bowes, G.//Albrecht, S.L. 043 in Green Report Series Response of Rice to Subambient and Superambient Carbon Dioxide Concentrations. 1986-1987 Progress ReportWashington, D.C.U.S. Dept. of Energy, Carbon Dioxide Research Division, and U.S. Dept. of Agriculture, Agric. Res. Serv.1988#Response of Vegetation to Carbon Dioxide/rice/Oryza sativa0SPAR units/pre-industrial CO2 concentration/gr owth stages/yield/allocation/canopy photosynthesis/transpiration/carbohydrates/stomatal density/ribulose bisphosphate carboxylase/Cyanobacteria/Anabaena variabilis\uReynolds, J.F.;Dougherty, R.L.;Tenhunen, J.D.;Harley, P.C. 042 in Green Report Series A Model for the Simulation of Plant Response to Elevated CO2Washington, D.C.U.S. Dept. of Energy, Carbon Dioxide Research Division1988#Response o f Vegetation to Carbon Dioxide0modeling/photosynthesis model/generic model\/Hendrey, G.R.//Lewin, K.F.//Lipfert, F.//Kolber, Z.//Daum, M. 045 in Green Report Series Free-Air Carbon Dioxide Enrichment (FACE) Facility Development: I. Concept, Prototype Design and PerformanceWashington, D.C.U.S. Dept. of Energy,  Carbon Dioxide Research Division1988#Response of Vegetation to Carbon Dioxide0FACE/exposure methods\0Hendrey, G.R.//Lipfert, F.W.//Kimball, B.A.//Hileman, D.R.//Bhattacharya, N.C. 046 in Green Report Series Free Air Carbon Dioxide Enrichment (FACE) Facility Development: II. Field Tests at Yazoo City, MS, 1987Washington, D.C.U.S. Dept. of Energy, Carbon Dioxide Research Division1988#Response of Vegetation to Carbon Dioxide/cotton/Gossypium hirsutum0FACE/leaf photosynthesis/conductance/open-top chambers/modeling/growth model/exposure methods\Cure, J.D.//Galloway, L.F.//El Dodo, M.//Israel, D.W.//Jr., T.W. Rufty, 048 in Green Report Series Growth and Carbon Budgets of Soybean Leaves Exposed to Elevated Carbon DioxideWashington, D.C.U.S. Dept. of Energy, Carbon Dioxide Research Division1989#Response of Vegetation to Carbon Dioxide/soybean/Glycine max0controlled environment chambers/growth/carbon budget/source-sink balance/leaf area development/leaf photosynthesis/remobilization/assimilate partitioning\Kimball, B.A.//Mauney, J.R.//Akey, D.H.//Hendrix, D.L.//Allen, S.G.//Idso, S.B.//Radin, J.W.//Lakatos, E.A. 049 in Green Report Series Effects of Increasing Atmospheric CO2 on the Growth, Water Relations, and Physiology of Plants Grown under Optimal and Limiting Levels of Water and NitrogenWashington, D.C.U.S. Dept. of Energy, Carbon Dioxide Research Division and U.S. Dept. of Agriculture, Agric. Res. Serv.1987#Response of Vegetation to Carbon Dioxide/cotton/Gossypium hirsutum0open-top chambers/water stress/nitrogen/beet armyworm/FACE/FIZZ irrigation/growth model/leaf photosynthesis/stomata/exposure methods\Chaudhuri, U.N.//Kanemasu, E.T.//Kirkham, M.B. 050 in Green Report Series Effect of Elevated Levels of CO2 on Winter Wheat under Two Moisture RegimesWashington, D.C.U.S. Dept. of Energy, Carbon Dioxide Research Division1989#Response of Vegetation to Carbon Dioxide/wheat/Triticum aestivum0rhizotron/outdoor growth chambers/water stress/growth stages/transpiration/yield/WUE\Drake, B.G.//Arp, W.J.//Balduman, L.//Curtis, P.S.//Johnson, J.//Kabara, D.//Leadley, P.W.//Pockman, W.T.//Seliskar, D.//Sutton, M.L.//Whigham, D.//Ziska, L. 051 in Green Report Series Effects of Elevated CO2 on Chesapeake Bay Wetlands. IV. Ecosystem and Whole Plant Responses. April-November 1988.Washington, D.C.U.S. Dept. of Energy, Carbon Dioxide Research Division1989#Response of Vegetation to Carbon Dioxide/Scirpus olneyi/Spartina patens/Distichlis spicata/Glycine max/soybean/Lycopersicon esculentum/tomato/Manihot esculentum/Amaranthus hypochondriacus/amaranth/Acacia mangium/Ficus obtusifolia/Paspallum conjugatum/Pharus latifolia/Psychotria limonensis/Tabebuia rosea0open-top chambers/salt marsh/aquatic plants/roots/nitrogen/growth/leaf photosynthesis/canopy photosynthesis/photosynthetic acclimation/respiration/carbon budget/evapotranspiration/C3/C4/species competition/community level CO2 responses/litter quality//litter decomposition/halophytes\~Kimball, B.A.//Akey, D.H.//Mauney, J.R.//Idso, S.B.//Allen, S.G.//Hendrix, D.L.//Radin, J.W 052 in Green Report Series Elevated CO2: Modeling Crop Response, Interaction with Temperature, Effects on Trees and InsectsWashington, D.C.U.S. Dept. of Energy, Carbon Dioxide Research Division, and U.S. Dept. of Agriculture, Agric. Res. Serv.1988#Response of Vegetation to Carbon Dioxide/cotton/Gossypium hirsutum/Agave vilmoriniana/Citrus aurantium/orange trees/sorghum/Sorghum bicolor0open-top chambers/trees/modeling/crop model/temperature/insects/herbivory/FACE/Spodoptera exigua/beet armyworm/CAM/FIZZ irrigation\@Baker, J.T.//Jr., L.H. Allen,//Boote, K.J.//Rowland-Bamford, A.J.//Jones, J.W.//Jones, P.H.//Bowes, G.//Laugel, F. 053 in Green Report Series Temperature and CO2 Effects on Rice. 1988 Progress ReportWashington, D.C.U.S. Dept. of Energy, Carbon Dioxide Research Division, and U.S. Dept. of Agriculture, Agric. Res. Serv.1989#Response of Vegetation to Carbon Dioxide/Oryza sativa/rice0SPAR units/temperature/growth stages/yield/canopy photosynthesis/evapotranspiration/respiration/c arbohydrates/ribulose bisphosphate carboxylase/sucrosephosphate synthase\Drake, B.G.//Arp, W.J.//Balduman, L.//Cousimano, R.//Dacey, J.//D'Abundo, D.//Hogan, K.//Long, S.//Pockman, W.T.//Utley, P.//Villegas, A.C.//Whigham, D. 055 in Green Report Series Effects of Elevated CO2 on Chesapeake Bay Wetlands. V. Eco"system and Whole Plant Responses. April-November 1989Washington, D.C.U.S. Dept. of Energy, Carbon Dioxide Research Division1990#Response of Vegetation to Carbon Dioxide/Scirpus olneyi/Spartina patens0open-top chambers/salt marsh/water status/#WUE/canopy photosynthesis/methane/evapotranspiration/nitrogen/ecosystem level CO2 responses/leaf photosynthesis/roots/quantum requirement/respiration/halophytes\Kirkham, M.B.//Kanemasu, E.T.//Harbers, G.W.//Reed, D.W.//He, H.//Theisen, R.D.//Bolger, T.P.//Goodrum, D.E.//Ballou, L.K.//Lawlor, D.J.//Nie, D.//Lu, W.P. 056 in Green Report Series Rangeland-Plant Response to Elevated CO2Washington, D%.C.U.S. Dept. of Energy, Carbon Dioxide Research Division1990#Response of Vegetation to Carbon Dioxide/Andropogon gerardii/big bluestem0outdoor growth chambers/tallgrass prairie/grasses/sedges/Forbs/leaf photosynthesis/transpiration/conductance&/growth/rangeland\Allen, L.H., Jr.//Beladi, S.E. 057 in Green Report Series Free-Air CO2 Enrichment (FACE): Analysis of Gaseous Dispersion Arrays for the Study of Rising Atmospheric CO2 Effects on Vegetation. 1983-1989 Progress ReportWashington, D.C.U.(S. Dept. of Energy, Carbon Dioxide Research Division, and U.S. Dept. of Agriculture, Agric. Res. Serv.1990#Response of Vegetation to Carbon Dioxide0FACE/exposure methods\8Bailly, J.//Coleman, J.R.Effect of CO2 Concentration on Protein Biosynthesis and Carbonic Anhydrase Expression in Chlamydomonas reinhardtii Plant Physiology198887833-840-Plant Physiol.. The effect of external inorganic carbon (*Ci) concentrations on protein biosynthesis and carbonic anhydrase (CA) mRNA abundance were examined in the eukaryotic alga Chlamydomonas reinhardtii. Transfer of high CO2 (5%) grown algae to air levels of CO2 resulted in the transitory synthesis of t+wo polypeptides of approximately 49,000 and 52,000 daltons as well as prolonged synthesis and accumulation of the 37,000 dalton CA monomer and an unidentified 20,000 dalton polypeptide. The gene coding for carbonic anhydrase was isolated from a genom,ic expression library and subjected to restriction endonuclease analysis. Southern blot analysis of chromosomal DNA indicates that only a single copy of the gene is present. The 2.5 kilobase DNA fragment hybridizes specifically to a 1.4 kilobase tra-nscript in RNA isolated from air-grown cells and from cells grown on 5% CO2 that have been exposed to air levels of CO2. Maximum mRNA abundance was observed after 1 to 3 hours of exposure to air. Transfer of air-grown cells to a high CO2 environment. resulted in the elimination of the CA transcript after 60 minutes of exposure. Changes in CA transcript abundance in response to external Ci concentrations occurred in the presence or absence of light./Chlamydomonas reinhardtii0algae/enzymes/carbo/nic anhydrase/gene expression/aquatic plants/cell culture\Rs  f  ;Baker, J.T.//Jr., L.H. Allen,//Boote, K.J.Growth and Yield Responses of Rice to Carbon Dioxide Concentration Journal of Agricultural Science, Cambridge1990115313-320-J. Agric. Sci., Camb.. Rice plants (Oryza sativa L., cv. IR301) were grown in paddy culture in outdoor, naturally sunlit, controlled-environment, plant growth chambers at Gainesville, Florida, USA, in 1987. The rice plants were exposed throughout the season to subambient (160 and 250), ambient (330) or superamb2ient (500, 660, 900 umol CO2/mol air) CO2 concentrations. Total shoot biomass, root biomass, tillering, and final grain yield increased with increasing CO2 concentration, the greatest increase occurring between the 160 and 500 umol CO2/mol air treatm3ents. Early in the growing season, root:shoot biomass ratio increased with increasing CO2 concentration; although the ratio decreased during the growing season, net assimilation rate increased with increasing CO2 concentration and decreased during th4e growing season. Differences in biomass and lamina area among CO2 treatments were largely due to corresponding differences in tillering response. The number of panicles/plant was almost entirely responsible for differences in final grain yield amon5g CO2 treatments. Doubling the CO2 concentration from 330 to 660 umol CO2/mol air resulted in a 32% increase in grain yield. These results suggest that important changes in the growth and yield of rice may be expected in the future as the CO2 concen6tration of the earth's atmosphere continues to rise./rice/Oryza sativa0growth analysis/pre-industrial CO2 concentration/allocation/SPAR units\*  >Baker, J.T.//Jr., L.H. Allen,//Boote, K.J.Response of Rice to Carbon Dioxide and Temperature Agricultural and Forest Meteorology199260153-166-Agric. For. Meteorol.. The current increase in atmospheric carbon dioxide concentrati8on ([CO2]) along with predictions of possible future increases in global air temperatures have stimulated interest in the effects of [CO2] and temperature on the growth and yield of food crops. This study was conducted to determine the effects and po9ssible interactions of [CO2] and temperature on the growth and yield of rice (Oryza sativa L., cultivar IR-30). Rice plants were grown for a season in outdoor, naturally sunlit, controlled-environment, and plant growth chambers. Temperature treatmen:ts of 28/21/25, 34/27/31, and 40/33/37C (daytime dry bulb air temperature/night-time dry bulb air temperature/paddy water temperature) were maintained in [CO2] treatments of 330 and 660 umol CO2/mol air. In the 40/33/37C temperature treatment, plan;ts in the 330 umol/mol [CO2] treatment died during stem extension while the [CO2] enriched plants survived but produced sterile panicles. Plants in the 34/27/31C temperature treatments accumulated biomass and leaf area at a faster rate early in the <growing season than plants in the 28/21/25C temperature treatments. Tillering increased with increasing temperature treatment. Grain yield increases owing to [CO2] enrichment were small and non-significant. This lack of [CO2] response on grain yie=ld was attributed to the generally lower levels of solar irradiance encountered during the late fall and winter when this experiment was conducted. Grain yields were affected much more strongly by temperature than [CO2] treatment. Grain yields decli>ned by an average of approximately 7-8% per 1C rise in temperature from the 28/21/25 to 34/27/31C temperature treatment. The reduced grain yields with increasing temperature treatment suggests potential detrimental effects on rice production in som?e areas if air temperatures increase, especially under conditions of low solar irradiance./rice/Oryza sativa0temperature/growth/yield/SPAR units\*4 @ ABaker, J.T.//Jr., L.H.Allen,//Boote, K.J.Temperature Effects on Rice at Elevated CO2 Concentration Journal of Experimental Botany199243959-964-J. Exp. Bot.. The continuing increase in atmospheric carbon dioxide concentration ([ACO2]) and projections of possible future increases in global air temperatures have stimulated interest in the effects of these climate variables on agriculturally important food crops. This study was conducted to determine the effects of [CO2] and teBmperature on rice (Oryza sativa L., cv. IR-30). Rice plants were grown season-long in outdoor, naturally sunlit, controlled-environment, plant growth chambers in temperature regimes ranging from 25/18/21C to 37/30/34C (daytime dry bulb air temperatCure/night-time dry bulb air temperature/paddy water temperature) and [CO2] of 660 umol CO2/mol air. An ambient chamber was maintained at a [CO2] of 330 umol/mol and temperature regime of 28/21/25C. Carbon dioxide enrichment at 28/21/25C increased Dboth biomass accumulation and tillering and increased grain yield by 60%. In the 660 umol/mol [CO2] treatment, grain yield decreased from 10.4 to 1.0 Mg/ha with increasing temperature from 28/21/25C to the 37/30/34C temperature treatment. Across tEhis temperature range, the number of panicles/plant nearly doubled while the number of seeds/panicle declined sharply. These results indicate that while future increase in atmospheric [CO2] are likely to be beneficial to rice growth and yield, potentFially large negative effects on rice yield are possible if air temperatures also rise./rice/Oryza sativa0temperature/growth/yield/seed production/SPAR units\*  =Baker, J.T.//Jr., L.H. Allen,//Boote, K.J.//Jones, P.//Jones, J.W.Response of Soybean to Air Temperature and Carbon Dioxide Concentration Crop Science19892998-105-Crop Sci.. Documented increases in global atmospheric CO2 concenHtration have stimulated interest in the direct effects of CO2 on plant growth and yield as well as the interactive effects of CO2 with other major climatic variables. This study was conducted to determine the effects and interactions of CO2 concentraItion and air temperature on the development, growth, total nonstructural carbohydrate (TNC), and final seed yield of soybean [Glycine max (L.) Merr., cv. Bragg] grown season-long in naturally lit, controlled-environment chambers. Day/night air temperJatures of 26/19, 31/24 and 36/29C were maintained in CO2 treatments of 330 and 660 umol CO2/mol air. Both CO2 enrichment and increasing air temperature decreased main stem plastochron interval, while increasing air temperature increased final mainstKem node number. Leaf area and above-ground biomass increased with CO2 enrichment and with temperature from 26/19C to 31/24C. The nonlinear increase with temperature in leaf area, aboveground biomass, and plastochron interval was attributed to the Lhighest temperature treatment being near or above the optimum for soybean growth and development. Seed yield increased with CO2 enrichment due mainly to an increase in seed number rather than weight per seed. Individual seed weight decreased, while Mseed number increased with increasing temperature. Leaflet TNC was relatively stable throughout the day. Stem TNC was less affected by CO2 than by temperature treatment and decreased with increasing temperature. These results indicate that the respoNnse of soybean to elevated CO2 concentration is highly temperature dependent./soybean/Glycine max0seeds/reproduction/temperature/yield/carbohydrates/SPAR units\*d o :Baker, J.T.; Jr., L.H. Allen,;Boote, K.J.; Jones, P.; Jones, J.W.Developmental Responses of Rice to Photoperiod and Carbon Dioxide Concentration Agricultural and Forest Meteorology199050201-210-Agric. For. Meteorol.. The documePnted increase in the carbon dioxide concentration of the Earth's atmosphere has stimulated interest in the effects of CO2 on plants and in particular the future prospects for the world's food supplies. While rice is a major food crop, relatively littQle is known about the effects of CO2 concentration on the timing of physiological growth stages and total growth duration, which are important aspects of a rice cultivar's adaptability to the environment of a particular geographic region. The objectiRve of this study was to determine the developmental responses of a modern, improved rice cultivar (Oryza sativa, cultivar 'IR-30') to a range of CO2 concentrations under two contrasting photoperiods. Rice plants were grown season-long in an outdoor, Snaturally lit, computer-controlled environment, plant growth chambers in CO2 concentrations of 160, 250 (subambient), 330 (ambient), 500, 660 and 900 (superambient) umol CO2/mol air. The entire experiment was conducted twice during 1987. The first oTr early planted rice (EPR) experiment was conducted with photoperiod extension lights during the vegetative phase of development, while the second or late-planted rice (LPR) experiment was conducted using only naturally occurring photoperiod. In bothU experiments, mainstem leaf developmental rates were greater during vegetative rather than reproductive growth stages and leaf appearance rates increased with CO2 treatment during vegetative development. In the LPR experiment, panicle initiation and Vboot stage occurred earlier and total growth duration was shortened for rice plants in the superambient compared with ambient and subambient CO2 treatments. This acceleration of plant development with increasing CO2 treatment was associated with a COW2-induced decrease in the number of mainstem leaves formed during the vegetative phase of growth. The reduced developmental response of rice plants to CO2 in the EPR compared with the LPR experiment was attributed to the artificially extended photopeXriod during the EPR experiment forcing a delay in the onset of reproductive development particularly in the superambient treatments. The CO2-induced acceleration of development and shortening of total growth duration should become a topic of interestY for rice agronomists and breeders involved with selecting rice cultivars and agronomic practices for a particular geographic region in view of the continued increases in global atmospheric CO2 concentration./rice/Oryza sativa0growth stages/photoperZiod/pre-industrial CO2 concentration/SPAR units\*D P CBaker, R.G.E.;Boatman, D.J.Some Effects of Nitrogen, Phosphorus, Potassium and Carbon Dioxide Concentration on the Morphology and Vegetative Reproduction of Sphagnum cuspidatum Ehrh. New Phytologist1990116604-611-New Phytol.. F\ive experiments are described which were designed to investigate the effects of varying the concentrations of nitrate, phosphate, potassium and carbon dioxide in the culture solution on the morphology and vegetative reproduction of Sphagnum cuspidatum] Ehrh. The plants were grown axenically from spores sown on agar containing inorganic salts and then transferred to aqueous culture solutions through which air containing enhanced concentrations of carbon dioxide was passed. In three of the experi^ments the plants were grown in a balanced inorganic salt solution at various dilutions and in two of these the concentration of carbon dioxide in the gas bubbled through the solution was varied. The concentrations of nitrogen, phosphorus and potassiu_m were varied independently and in combination in the remaining experiments while the concentration of carbon dioxide was kept constant. In some of the experiments the minimum concentrations of nitrogen and potassium supplied were considerably belo`w the minimum average concentrations recorded in rain but the minimum concentration of phosphorus supplied was within the upper part of the range recorded in rain. Within the ranges supplied the concentrations of all three elements and of carbon dioxaide affected interfascicle length and vegetative reproduction (innovation formation) but it was concluded that the element limiting innovation formation in natural conditions is phosphorus./Sphagnum cuspidatum0nutrition/nitrogen/phosphorus/potassiumb/vegetative reproduction/controlled environment chambers\R    BBaker, J.T.// Laugel, F.// Boote, K.J.// Jr., L.H. Allen,Effects of Daytime Carbon Dioxide Concentration on Dark Respiration in Rice Plant, Cell and Environment199215231-239-Plant Cell Environ.. Rising atmospheric carbon dioxidde concentration ([CO2]) has generated considerable interest in the response of agricultural crops to [CO2]. The objectives of this study were to determine the effects of a wide range of daytime [CO2] on dark respiration of rice (Oryza sativa L. cv. IeR-30). Rice plants were grown season-long in naturally sunlit plant growth chambers in subambient (160 and 250), ambient (330), or superambient (500, 660 and 900 umol CO2/mol air) [CO2] treatments. Canopy dark respiration, expressed on a ground areaf basis (Rd) increased with increasing [CO2] treatments and was very similar among the superambient treatments. The trends in Rd over time and in response to increasing daytime [CO2] treatment were associated with and similar to trends previously descgribed for photosynthesis. Specific respiration rate (Rdw) decreased with time during the growing season and was higher in the subambient than the ambient and superambient [CO2] treatments. This greater Rdw in the subambient [CO2] treatments was attrhibuted to a higher specific maintenance respiration rate and was associated with higher plant tissue nitrogen concentration./rice/Oryza sativa0SPAR units/pre-industrial CO2 concentration/nitrogen/respiration\*  iDBaldocchi, D.D.//White, R.//Johnston, J.W.A Wind Tunnel Study to Design Large, Open-top Chambers for Whole-tree Pollutant Exposure Experiments Journal of the Air Pollution Control Association198939549-1556-JAPCA. A wind tunnel kstudy was conducted to determine the optimal design features of a large, open-top chamber, as needed for pollution exposure studies on mature trees. An optimally-designed, open-top chamber must minimize the incursion of ambient air through its openinlg and maintain a uniform treatment concentration throughout the chamber. The design features of interest are the diameter and height of the chamber and the deflection angle and opening size of any frustum that may be mounted on top of a model chamberm. Design specifications depend on the turbulence regime about the chamber, which is influenced by the nature of the surrounding vegetation. Consequently, our investigation was performed on scale-model, open-top chambers in a wind tunnel populated wnith a model coniferous forest. Turbulence measurements demonstrated the similarity between the turbulence regime of the model and a natural forest. A hydrocarbon tracer was injected into the wind tunnel flow to characterize chamber performance. Tohe main design features of open-top chambers are the velocity of air exiting through the top and the relationship between the length scale of the turbulence and the diameter of the chamber opening. As exit velocities increase, the proportion of eddieps with sufficient force to penetrate into the chamber decrease. Therefore, for equal volumetric air flows, smaller opening sizes increase the exit velocities and reduce the number and extent of ambient air incursions. Almost total exclusion of ambieqnt air is achieved as the exit velocity of the air exceeds the magnitude of one standard deviation of the vertical wind velocity measured at the chamber top. The incursion of ambient air is also reduced when the diameter of the chamber opening is smarller than the characteristic length scale of the turbulence, a measure of mean eddy size. Frusta deflect air flow over the chamber. Three prototypes, with 30-, 45- and 60-degree angles were tested. A 30-degree frustum slightly improves the perforsmance of the chamber and is more effective in preventing ambient air from entraining into the chamber opening than frusta with either a 45- or 60-degree angle. A flatter frustum allows for a smoother transition in the wind velocity streamline and is tless apt to cause wake turbulence, as is the case with steeper frusta. Knowledge of the turbulence characteristics of plant canopies are readily available in the literature and can aid scientists and engineers in designing the optimal chamber and furusta dimensions for their particular application. Therefore, the empirical approach to chamber design can be avoided, and substantial savings can be realized.0open-top chambers/air pollution/exposure methods\FBarlow, E.W.R//Conroy, J.Influence of Elevated Atmospheric Carbon Dioxide on the Productivity of Australian Forestry Plantations Pearman, G.I. ed. Greenhouse: Planning for Climate ChangeNew YorkE.J. Brill1988520-533. Australwia produced $2.7 billion worth of forest products in 1983-84 but a further $1.3 billion worth, principally softwood, were imported. Because of this ever increasing demand for softwood, there is a move away from utilization of native hardwoods and by x2020 AD, when the atmospheric CO2 concentration is likely to be greater than 450 ppmv, 75% of forest products are projected to come from coniferous plantations. This move towards Pinus radiata is a result of both demand for softwood and lack of indepyth investigations of the potential of Australian native species, particularly eucalypts, for plantation forestry. Pinus radiata is the major plantation softwood in southern Australia and is presently grown at sites where phosphorus deficiency and rzepeated episodes of drought are common. Consequently, we are investigating the growth response of pines to elevated CO2 at a range of phosphorus and water levels. When phosphorus was adequate, doubling CO2 concentration more than doubled the rate of{ photosynthesis and increased the total plant dry weight by about 40%. However, there was no response when phosphorus was deficient. In contrast, there was a slightly higher response under simulated drought conditions. A further possible effect o|f rising CO2 levels is that the climatic range of P. radiata may be altered due to a reduction in water use or an increase in the drought tolerance of the trees. We found that CO2 enrichment did not affect either of these factors but the water-use ef}ficiency was increased when phosphorus was adequate. All families of P. radiata do not respond to CO2 enrichment in the same manner. In a study investigating the response of four families to elevated CO2 at two phosphorus levels, we have identifie~d a considerable variation between the families in their response to CO2 and phosphorus. To date our studies have indicated that the projected increase in atmospheric CO2 levels is likely to have a significant influence on the productivity of Australia's P. radiata plantations. But this will only occur if phosphorus fertilization is adequate. If the rise in CO2 results in climatic change the range of P. radiata may be even further restricted because there will be no concomitant decrease in water use or increase in drought tolerance. There is an urgent need for complementary studies of the response of Australian native species to elevated CO2 at realistic levels of phosphorus and water to enable more accurate prediction of the productivity and water use of Australian native forests and eucalyptus plantations./Pinus radiata0review/allocation/conductance/family responses/growth/nutrition/phosphorus/pot volume/trees/WUE/water stress/leaf photosynthesis/forest\   c p   " ,    n  x HBarr, A.G.//King, K.M.//Thurtell, G.W//Graham, M.E.DHumidity and Soil Water Influence the Transpiration Response of Maize to CO2 Enrichment Canadian Journal of Plant Science199070941-948-Can. J. Plant Sci.. The impact of increasing atmospheric CO2 on the productivity of C4 crops may vary with soil water availability. This study investigates the hypothesis that elevating CO2 in Zea mays L. reduces the degree to which transpiration is limited by soil water at high vapor pressure deficits or low soil water contents. Plants growing in controlled environments at 300 and 600 umol/mol CO2 were exposed daily to five levels of vapor pressure deficit as water was withheld and the soil dried over an 8-d period. Doubling CO2 caused an overall reduction of 23% in the transpiration rate and 34% in the leaf conductance, but the effect of CO2 on transpiration and leaf conductance was greatest at high soil water content and low vapor pressure deficit, when soil water least limited transpiration. Implications for the productivity of C4 crops in the field are discussed./corn/Zea mays0C4/VPD/water stress/conductance/transpiration/controlled environment chambers/humidity\*  IBarson, M.M.//Gifford, R.M.Carbon Dioxide Sinks: The Potential Role of Tree Planting in Australia Swain, D.J. ed. Greenhouse and EnergyAustraliaCSIRO1990433-443. Reforestation has been suggested as a possible policy option at several recent international "greenhouse effect" forums. The issue of deforestation/reforestation may be the subject of a protocol for which detailed arrangements will be developed following the establishment of a non-obligatory Framework Convention on Climate Change in the early 1990's. Although forestry cannot in principle offer a permanent solution to continuous emission of CO2 from fossil fuel burning, its expansion could assist in slowing down net emissions. This would "buy time" to reduce rates of CO2 emission and to develop strategies to adapt to global atmospheric and climate change. A simple model is developed to explore the dynamics of carbon sequestration by new forest plantations. The areal extent of land suitable for reforestation is also examined. It is concluded from one optimistic scenario that a program of planting 40,000 ha/y of new forest onto non-forested land could, after 20 y absorb about 5-12 Mt (C) p.a. (7-17 per cent 1987-88 total Australian emissions) as long as planting at that rate continued.0trees/modeling/reforestation\JBauerle, W.L.//Kretchman, D.//Tucker-Kelly, L.CO2 Enrichment in the U.S. Enoch, H.Z.//Kimball, B.A. eds. Status and CO2 SourcesBoca Raton, FloridaCRC Press, Inc.1986Vol.I49-57#Carbon Dioxide Enrichment of Greenhouse Crops0commercial use of CO2/greenhouse\MBazzaz, F.A.The Response of Natural Ecosystems to the Rising Global CO2 Levels Annual Review of Ecology and Systematics199021167-196-Ann. Rev. Ecol. Syst.0review/physiological CO2 responses/environmental interactions/species competition/family responses/population level CO2 responses/community level CO2 responses/ecosystem level CO2 responses/soil microorganisms/herbivory/species range/CO2 enrichment studies\NBazzaz, F.A.//Ackerly, D.D.//Woodward, F.I.//Rochefort, L.CO2 Enrichment and Dependence of Reproduction on Density in an Annual Plant and a Simulation of Its Population Dynamics Journal of Ecology199280643-651-J. Ecol.. 1. Populations of an annual plant, Abutilon theophrasti, were grown at four densities (100, 500, 1500 and 4000/m2) and two CO2 concentrations (350 and 700 uL/L) to examine the influence of CO2 environment on density-dependent patterns of demography and reproduction. Variables measured included survivorship, proportion of plants flowering and fruiting, number of fruiting individuals, number of seeds per individual, total seed production per population, mean seed mass, and germination of seeds produced in each environment. 2. All variables, except the number of fruiting individuals, declined with increasing density, and at the highest density no individuals set seed. The number of fruiting individuals was highest at a density of 500/m2. In the elevated CO2 environment, survivorship was significantly reduced but the proportion of plants flowering and fruiting and the number of fruiting individuals in each population all increased. Total population seed production was higher in the elevated CO2 environment at all densities, although the differences were not significant. Significant effects of CO2 concentration were observed only for population-level variables, but not for mean individual fecundity or seed size. Seed germination declined with increasing maternal density, and no germination was recorded for seeds produced at 1500 /m2. 3. Simple models of population dynamics, utilizing difference equations, were constructed to examine potential population-level consequences of these density and CO2 effects. In the absence of a persistent seed pool, the simulated populations exhibited damped or stable oscillations under low germination values, but displayed non-cyclic ('chaotic') oscillations or went extinct for higher germination due to the complete failure of seed-set at high density. Because of its higher fecundity, the elevated-CO2 population generally exhibited greater oscillations, and the critical germination value at which the simulated populations went extinct was much lower for the elevated-CO2 than for the ambient-CO2 population./Abutilon theophrasti0controlled environment chambers/old field communities/population model/plant density/reproduction/simulation/survivorship/modeling\*  OBazzaz, F.A.//Coleman, J.S.//Morse, S.R.Growth Responses of Seven Major Co-occurring Tree Species of the Northeastern United States to Elevated CO2 Canadian Journal of Forest Research1990201479-1484-Can. J. For. Res.. We examined how elevated CO2 affected the growth of seven co-occurring tree species: American beech (Fagus grandifolia Ehrh.), paper birch (Betula papyrifera Marsh.), black cherry (Prunus serotina Ehrh.), white pine (Pinus strobus L.), red maple (Acer rubrum L.), sugar maple (Acer saccharum Marsh.), and eastern hemlock (Tsuga canadensis (L.) Carr.). We also tested whether the degree of shade tolerance of species and the age of seedlings affected plant responses to enhanced CO2 levels. Seedlings that were at least 1 year old, for all species except beech, were removed while dormant from Harvard Forest, Petersham, Massachusetts. Seeds of red maple and paper birch were obtained from parent trees at Harvard Forest, and seeds of American beech were obtained from a population of beeches in Nova Scotia. Seedlings and transplants were grown in one of four plant growth chambers for 60 d (beech, paper birch, red maple, black cherry) or 100 d (white pine, hemlock, sugar maple) under CO2 levels of 400 or 700 uL/L. Plants were then harvested for biomass and growth determinations. The results showed that the biomass of beech, paper birch, black cherry, sugar maple, and hemlock significantly increased in elevated CO2, but the biomass of red maple and white pine only marginally increased in these conditions. Furthermore, there were large differences in the magnitude of growth enhancement by increased levels of CO2 between species, so it seems reasonable to predict that one consequence of rising levels of CO2 may be to increase the competitive ability of some species relative to others. Additionally, the three species exhibiting the largest increase in growth with increased CO2 concentrations were the shade-tolerant species (i.e., beech, sugar maple, and hemlock). Thus, elevated CO2 levels may enhance the growth of relatively shade-tolerant forest trees to a greater extent than growth of shade-intolerant trees, at least under the light and nutrient conditions of this experiment. We found no evidence to suggest that the age of tree seedlings greatly affected their response to elevated CO2 concentration./American beech/Fagus grandifolia/paper birch/Betula papyrifera/black cherry/Prunus serotina/white pine/Pinus strobus/red maple/Acer rubrum/sugar maple/Acer saccharum/eastern hemlock/Tsuga canadensis0trees/growth/shade tolerance/species competition/controlled environment chambers\G X n          $ 4 PBazzaz, F.A.//Fajer, E.D.Plant Life in CO2-Rich World Scientific American199226668-74-Sci. Amer.0review/photosynthesis/insects/C3/C4/ecosystem level CO2 responses/CO2 enrichment studies\LBazzaz, F.A./Garbutt, K.The Response of Annuals in Competitive Neighborhoods: Effects of Elevated CO2 Ecology198869937-946-Ecology. Four members of an annual community were used to investigate the effects of changing neighborhood complexity and increased CO2 concentration on competitive outcome. Plants were grown in monoculture and in all possible combinations of two, three, and four species in CO2-controlled growth chambers at CO2 concentrations of 350, 500, and 700 uL/L with ample moisture and high light. Species responded differently to enhanced CO2 level. Some species (e.g., Abutilon theophrasti) had increased biomass with increasing CO2, while others (e.g., Amaranthus retroflexus) had decreased biomass with increasing CO2 concentration. In mixtures, species tended to interact strongly, and, in some cases, the interaction canceled out the effects of CO2. Furthermore, there were clear differences in species behavior in different competitive neighbors. In general, competitive arrays that had C3 species depressed the response of C4 species, especially Amaranthus. Ambrosia artemisiifolia was the strongest competitor in the assemblage. Strong statistical interactions between CO2 and the identity of the competing species in mixtures were found to be primarily due to the as yet unexplained response of plants with CO2 at 500 uL/L. The potential effects of CO2 on community structure could be profound, particularly at the intermediate levels of CO2 that are predicted to be reached during the first half of the next century./Ambrosia artemisiifolia/Abutilon theophrasti/Amaranthus retroflexus/Setaria faberii0sunlit controlled environment chambers/old field communities/C3/C4/species competition\W k   = G I ` SBazzaz, F.A.//Garbutt, K.//Reekie, E.G.//Williams, W.E.Using Growth Analysis to Interpret Competition between a C3 and a C4 Annual under Ambient and Elevated CO2 Oecologia198979223-235-Oecologia. Detailed growth analysis in conjunction with information on leaf display and nitrogen uptake was used to interpret competition between Abutilon theophrasti, a C3 annual, and Amaranthus retroflexus, a C4 annual, under ambient (350 uL/L) and two levels of elevated (500 and 700 uL/L) CO2. Plants were grown both individually and in competition with each other. Competition caused a reduction in growth in both species, but for different reasons. In Abutilon, decreases in leaf area ratio (LAR) were responsible, whereas decreased unit leaf rate (ULR) was involved in the case of Amaranthus. Mean canopy height was lower in Amaranthus than Abutilon which may explain the low ULR of Amaranthus in competition. The decrease in LAR of Abutilon was associated with an increase in root:shoot ratio implying that Abutilon was limited by competition for below ground resources. The root:shoot ratio of Amaranthus actually decreased with competition, and Amaranthus had a much higher rate of nitrogen uptake per unit of root than did Abutilon. These latter results suggest that Amaranthus was better able to compete for below ground resources than Abutilon. Although the growth of both species was reduced by competition, generally speaking, the growth of Amaranthus was reduced to a greater extent than that of Abutilon. Regression analysis suggests that the success of Abutilon in competition was due to its larger starting capital (seed size) which gave it an early advantage over Amaranthus. Elevated CO2 had a positive effect upon biomass in Amaranthus, and to a lesser extent, Abutilon. These effects were limited to the early part of the experiment in the case of the individually grown plants, however. Only Amaranthus exhibited a significant increase in relative growth rate (RGR). In spite of the transitory effect of CO2 upon size in individually grown plants, level of CO2 did effect final biomass of competitively grown plants. Abutilon grown in competition with Amaranthus had a greater final biomass than Amaranthus at ambient CO2 levels, but this difference disappeared to a large extent at elevated CO2. The high RGR of Amaranthus at elevated CO2 levels allowed it to overcome the difference in initial size between the two species./Abutilon theophrasti/Amaranthus retroflexus0sunlit controlled environment chambers/species competition/growth analysis/root:shoot ratio/nitrogen/old field communities/C3/C4\2R f y      < F L T v      M W       C K     $ ,         c k      (  2 KBazzaz, F.A./McConnaughay, K.D.M.Plant-plant Interactions in Elevated CO2 Environments Australian Journal of Botany199240547-563-Austr. J. Bot.. Increasing atmospheric carbon dioxide concentrations present a novel resource condition for plant communities. In order to understand and predict how plant community structure and function may be altered in a high CO2 world, we need to understand how interactions among neighboring plants within a community will alter the growth and reproduction of component species. Because CO2 is readily diffusible, plants have little influence on the CO2 acquisition of their neighbors, except within particularly dense canopies. Thus, plants seldom compete directly for CO2. Rather, CO2 availability is likely to alter plant-plant interactions indirectly through its effects on plant growth and competition for other resources. As a consequence, competitive outcome under elevated CO2 atmospheres within even simple systems is not easy to predict. For example, under some conditions, C4 species in competitive assemblages have improved competitive ability relative to C3 competitors as a result of CO2 enrichment, contrary to expectations based on their photosynthetic pathways. It is now clear that individually grown plants can differ substantially from those within mono- or multispecific stands in response to CO2 enrichment. At present, our understanding of how stands of interacting plants modify the availability of CO2 and other resources is incomplete. We urgently need information about how elevated CO2 atmospheres influence stand formation and population dynamics, specifically with regard to the identities, numbers, sizes and reproductive fitnesses of individuals within single and multiple species stands, if we are to make multi-generational predictions concerning the fate of populations and communities in an elevated CO2 world.0review/community level CO2 responses/plant-plant interactions/temperature/environmental interactions\QPolley, H.W.//Johnson, H.B.//Mayeux, H.S.Carbon Dioxide and Water Fluxes of C3 Annuals and C3 and C4 Perennials at Subambient CO2 Concentration Functional Ecology19926693-703-Funct. Ecol.. 1. The C3 annuals, Avena sativa and Brassica kaber, and C3 and C4 perennials, Prosopis glandulosa and Schizachyrium scoparium, respectively, were grown in a 38-m long chamber along a continuous gradient of daytime CO2 concentrations ([CO2]) from near the current 350 umol/mol to 150 (annuals) or 200 umol/mol (perennials). Diurnal CO2 and water fluxes were calculated for plant stands in five consecutive, 7.6-m lengths of the chamber arranged linearly along the [CO2] gradient. 2. The ratio of night respiration (Rn) to daytime net assimilation (Pd) was greatest in A. sativa/B. kaber exposed to mean [CO2] below 200 umol/mol, while Rn/Pd differed little among five stands of P. glandulosa/S. scoparium that were grown at mean [CO2] from 219 to 331 umol/mol. 3. Evapotranspiration was reduced and water-use efficiency (WUE) was increased in A. sativa/B. kaber stands by higher [CO2]. 4. Pd and WUE of P. glandulosa/S. scoparium were not related to [CO2] across either of two growing seasons. Both Pd and WUE, however, were greater at higher [CO2] in three of four stands when [CO2] was varied in consecutive days. 5. We conclude that past increases in atmospheric [CO2] have promoted higher WUE and increased carbon uptake in C3-dominated ecosystems./Avena sativa/oat/Brassica kaber/field mustard/Prosopis glandulosa/mesquite/Schizachyrium scoparium/little bluestem0gradient exposure tunnel/C3/C4/pre-industrial CO2 concentration/WUE/evapotranspiration/respiration\2     ( - D       F G I J q   , L M Z t   TBeer, S.The Fixation of Inorganic Carbon in Plant Cells Enoch, H.//Kimball, B.A. eds. Physiology, Yield, and EconomicsBoca Raton, FloridaCRC Press, Inc.1986Vol.II3-11#Carbon Dioxide Enrichment of Greenhouse Crops. The initial fixation of atmospheric inorganic carbon (CO2) in plant cells is carried out via either the C3 or C4 pathway. The first step of the C3 pathway is the fixation of CO2 by a five-carbon compound to yield two molecules of PGA (a three-carbon compound). PGA is subsequently reduced to form sugars. In the so-called C3 plants, this is the only pathway for incorporation of CO2. The enzyme (RuBPcase) catalyzing CO2 fixation in the C3 pathway may also act as an oxygenase. When doing so, glycolate (a two-carbon compound) is formed together with PGA, and there is no net carbon gain of the process. In the further metabolism of glycolate, CO2 is released. This is called photorespiration and its rate is, in contrast to mitochondrial or dark respiration, strongly enhanced by O2 and light. In the C4 pathway, atmospheric CO2 is fixed, via the enzyme PEPcase, by a three-carbon compound to yield one molecule of malate or aspartate (four-carbon compounds). In C4 plants, this occurs in mesophyll cells. Malate or aspartate is then transported to bundle sheath cells where it is decarboxylated, and the released CO2 is refixed via the C3 pathway. There is no apparent photorespiration in C4 plants, because CO2 levels in the vicinity of RuBPcase are probably elevated and any CO2 released from the bundle sheath cells is efficiently refixed via PEPcase in the mesophyll cells. In CAM plants, atmospheric CO2 is fixed into malate during the night while the decarboxylation and refixation of CO2 occurs in the daytime. The C4 pathway provides C4 and CAM plants with an efficient carbon-capturing system complementing the basic C3 pathway. In C4 plants this leads to a higher net CO2 incorporation rate than in C3 plants under high light and temperature regimes such as are found in the tropics. In CAM plants it allows for nightly CO2 fixation in arid climates where opening of stomates during the day would cause excessive water loss.0review/photosynthesis/C3/C4/CAM/enzymes/metabolites\YBellamy, L.A.//Kimball, B.A.CO2 Enrichment Duration and Heating Credit as Determined by Climate Enoch, H.Z.//Kimball, B.A. eds. Physiology, Yield, and EconomicsBoca Raton, FloridaCRC Press, Inc.1986Vol.II168-197#Carbon Dioxide Enrichment of Greenhouse Crops. To determine if it is economical to invest in CO2 enrichment equipment, a detailed economic analysis considering the increases in income and operating expenses should be performed. The procedure for such an analysis is straightforward (e.g., Chapter 13) but it is necessary to make estimates of the percent increase in yield, the amount of CO2 used, and of any reduction in heating energy requirements resulting from a combustion-type CO2 generator. For any given greenhouse and crop, these three factors will vary with the local climate and in particular, with the outside air temperature, and global solar radiation. It is practical to enrich with CO2 only while a greenhouse is closed and not ventilated. Therefore, CO2 enrichment duration equals day length minus ventilation time. Using Kimball's MEB program curves were generated which show the ventilation time fraction a 0.05 m3/m2/s capacity (47 greenhouse volume changes per hour) fan would need to operate to maintain a given set point temperature as a function of transmitted solar radiation for various ambient air temperatures. Similar curves were generated showing the heating credit from a CO2 generator rated at 42.5 W/m2 (CO2 output 9.5 g/m2/h). Hourly solar radiation and temperature data for days typical of each month of the year for six climate regions were generated using simple models from values of monthly mean minimum and maximum temperatures and mean total daily global radiation. Such data should be available nearby to most greenhouse locations. The hourly climate data for each of the typical monthly days were used in conjunction with the ventilation time fraction curves to compute the ventilation requirement throughout the year for six locations--Oslo, Norway; De Bilt, Netherlands; Milan, Italy; Columbus, Ohio, U.S.; Tokyo, Japan; Tel Aviv, Israel. The number of hours at which the greenhouse operated in five ventilation classes (0%, 0 to 20%, 20 to 50%, 50 to 100%, 100%) for a 30C ventilation temperature setpoint were plotted. For all sites except Tel Aviv, enrichment is possible throughout the whole day during winter. At Oslo, a greenhouse can remain unventilated and enriched for up to 7 months of the year. The areas in each ventilation class were measured to estimate the corresponding annual number of hours of possible CO2 enrichment. From these CO2 enrichment duration values, the required amounts of CO2 can be estimated. The amount of solar radiation received by the crop during each of the ventilation classes was also determined, so that the percent increase in yield due to CO2 enrichment could be calculated. A greenhouse in Oslo can remain closed and CO2 enriched for 79% of the total annual daylight hours, yet only 51% of the total radiation is received by the crop during this time. Using the assumption that yield is directly proportional to transmitted solar radiation, yields with and without CO2 enrichment were compared for the six locations to assess the effect of climate on percent yield increase. Annual yields could be increased 2% at Tel Aviv and 26% at Oslo if enrichment is limited to when the greenhouse remains completely closed. If CO2 is pulsed into the greenhouse between intervals of fan operation, these CO2 response values can increase to 22 and 48%, respectively. The effects on CO2 enrichment duration of using "hot" CO2 from a combustion-type generator rather than "cold" CO2 from other sources were computed for the Tel Aviv location. Using a 27C greenhouse air temperature for the ventilation setpoint, average daily CO2 enrichment duration (0% ventilation) was 4.0 hr during the winter using cold CO2, but decreased to 2.6 hr with hot CO2. Finally, the annual heating credit was determined for each of the six locations for 15C day heating setpoint, and the annual and winter savings in heating energy requirements were tabulated. The proportion of annual CO2 enrichment duration (0% ventilation) that was heating credit time ranged from 49% for Oslo to 8% for Tel Aviv.0commercial use of CO2/greenhouse\ZBentley, B. L.//Johnson, N.D.Plants as Food for Herbivores: The Roles of Nitrogen Fixateion and Carbon Dioxide Enrichment Price, P.W.//Lewinsotin, T.M.//Fernandes, G.W.//Benson, W.W. eds. Plant-Animal Interactions: Evolutionary Ecology in Tropical and Temperate RegionsJohn Wiley & Sons, Inc.1990257-2720review/herbivory/insects/nitrogen fixation/carbon:nitrogen ratio\[Berntson, G.M.//Woodward, F.I.The Root System Architecture and Development of Senecio vulgaris in Elevated CO2 and Drought Functional Ecology19926324-333-Funct. Ecol.. 1. The impact of elevated CO2 and drought on the architecture and development of root systems of Senecio vulgaris was examined and implications for water and nutrient uptake discussed. Plants were grown in miniature rhizotrons to non-destructively monitor the development of roots in situ at both an elevated (700 umol/mol) and ambient (350 umol/mol) atmospheric CO2 concentration and high or low supply of water. 2. CO2 and water had a significant impact on the way that S. vulgaris root systems filled the soil matrix. Elevated CO2 resulted in more branched, longer root systems that foraged through larger volumes of soil. Under elevated CO2 and a low water supply, root systems had branching and foraging patterns and root length similar to those grown under ambient CO2 with a high water supply. 3. Overall, water had a more pronounced impact on the growth rate of S. vulgaris roots than did CO2. The density of rooting remained unchanged across all treatments. Thus, under elevated CO2 the intensity of foraging S. vulgaris root systems might be unchanged while the extent of foraging by these root systems, as indicted by the horizontal spread of roots, may be increased./Senecio vulgaris0water stress/roots/growth analysis/root:shoot ratio/rhizotron/greenhous\ O _  !       +   \Besford, R.T.The Greenhouse Effect: Acclimation of Tomato Plants Growing in High CO2, Relative Changes in Calvin Cycle Enzymes Journal of Plant Physiology1990136458-463. Tomato plants (cv. Findon Cross) were grown in a normal concentration of CO2 (approximately 340 vpm) or in elevated CO2 (1000 vpm) with a 12 h photoperiod of 400 umol quanta/m2/s, PAR. The activities of three Calvin cycle enzymes, RuBPco (E.C. 4.1.1.39), 3 phosphoglyceric acid phosphokinase (E.C. 2.7.2.3) and NADP-dependent glyceraldehyde 3-phosphate dehydrogenase (E.C. 1.2.1.13) were determined in extracts from the unshaded 5th leaf during leaf development. RuBPco activity was reduced in the high-CO2 grown leaves at 60% expansion compared with leaves grown in 340 vpm CO2, but there were no apparent differences in the other two Calvin cycle enzymes at this stage of expansion. With subsequent leaf development in high CO2 there was an accelerated decline in all three enzyme activities. The loss of RuBPco activity was studied further by raising antibodies to RuBPco and the large subunit of RuBPco (LSU) was detected in electroblotted crude extracts from normal and high-CO2 grown plants. This specific immunoassay estimated a 75% reduction of LSU in the high-CO2 grown leaf at full expansion./Lycopersicon esculentum0enzymes/photosynthetic acclimation/Calvin cycle enzymes/controlled environment chambers\^Besford, R.T.//Hand, D.W.The Effects of CO2 Enrichment and Nitrogen Oxides on some Calvin Cycle Enzymes and Nitrite Reductase in Glasshouse Lettuce Journal of Experimental Botany198940329-336-J. Exp. Bot.. Glasshouse lettuce (c