scholarly journals Effect of water addition and nitrogen fertilization on the fluxes of CH<sub>4</sub>, CO<sub>2</sub>, NO<sub>x</sub>, and N<sub>2</sub>O following five years of elevated CO<sub>2</sub> in the Colorado Shortgrass Steppe

2003 ◽  
Vol 3 (5) ◽  
pp. 1703-1708 ◽  
Author(s):  
A. R. Mosier ◽  
E. Pendall ◽  
J. A. Morgan
Keyword(s):  
Elevated Co2 ◽  
Plant Biomass ◽  
Co2 Enrichment ◽  
Surface Fluxes ◽  
Shortgrass Steppe ◽  
Water Addition ◽  
No Emission ◽  
Ch4 Uptake ◽  
N2o Fluxes ◽  
Ambient Co2

Abstract. An open-top-chamber (OTC) CO2 enrichment (~720 mmol mol-1) study was conducted in the Colorado shortgrass steppe from April 1997 through October 2001. Aboveground plant biomass increased under elevated CO2 and soil moisture content was typically higher than under ambient CO2 conditions. Fluxes of CH4, CO2, NOx and N2O, measured weekly year round were not significantly altered by CO2 enrichment over the 55 month period of observation. During early summer of 2002, following the removal of the open-top-chambers from the CO2 enrichment sites in October 2001, we conducted a short term study to determine if soil microbial processes were altered in soils that had been exposed to double ambient CO2 concentrations during the growing season for the past five years. Microplots were established within each experimental site and 10 mm of water or 10 mm of water containing the equivalent of 10 g m-2 of ammonium nitrate-N was applied to the soil surface. Fluxes of CO2, CH4, NOx and N2O fluxes within control (unchambered), ambient CO2 and elevated CO2 OTC soils were measured at one to three day intervals for the next month. With water addition alone, CO2 and NO emission did not differ between ambient and elevated CO2 soils, while CH4 uptake rates were higher and N2O fluxes lower in elevated CO2 soils. Adding water and mineral N resulted in increased CO2 emissions, increased CH4 uptake and decreased NO emissions in elevated CO2 soils. The N addition study confirmed previous observations that soil respiration is enhanced under elevated CO2 and N immobilization is increased, thereby decreasing NO emission.

scholarly journals Soil-atmosphere exchange of CH<sub>4</sub>, CO<sub>2</sub>, NO<sub>x</sub>, and N<sub>2</sub>O in the Colorado Shortgrass Steppe following five years of elevated CO<sub>2</sub> and N fertilization

2003 ◽  
Vol 3 (3) ◽  
pp. 2691-2706 ◽  
Author(s):  
A. R. Mosier ◽  
P. Pendall ◽  
J. A. Morgan
Keyword(s):  
Elevated Co2 ◽  
Co2 Enrichment ◽  
Shortgrass Steppe ◽  
Plant Production ◽  
Trace Gas ◽  
No Emission ◽  
Ch4 Uptake ◽  
N2o Fluxes ◽  
The Impact ◽  
Ambient Co2

Abstract. An open-top-chamber (OTC) CO2 enrichment study was conducted in the Colorado shortgrass steppe to determine the effect of elevated CO2 (~720 mmol mol−1) on plant production, photosynthesis, and water use of this mixed C3/C4 plant community, soil nitrogen (N) and carbon (C) cycling and the impact of changes induced by \\CO2 on trace gas exchange. Weekly measurements of CO2, CH4, NOx and N2O fluxes within control (unchambered), ambient CO2 and elevated CO2 OTCs and soil water and temperature were measured at each flux measurement time from early April 1997, year round, through October 2001. Even though both aboveground plant biomass increased under elevated CO2 and soil moisture content was typically higher than under ambient CO2 conditions, none of the trace gas fluxes were significantly altered by CO2 enrichment over the 55 month period of observation. During early summer of 2002, following the removal of the open-top-chambers from the CO2 enrichment sites in October, we conducted a short term study to determine if soil microbial processes were altered in soils that had been exposed to double ambient CO2 concentrations during the growing season for the past five years. Microplots were established within each experimental site and 10 mm of water or 10 mm of water containing the equivalent of 10 g m−2 of ammonium nitrate-N was applied to the soil surface. Fluxes of CO2, CH4, NOx and N2O fluxes within control (unchambered), ambient CO2 and elevated CO2 OTCs soils at one to three day intervals for the next month. With water addition alone, CO2 and NO emission did not differ between ambient and elevated CO2 soils, while CH4 uptake rates were higher and N2O fluxes lower in elevated CO2 soils. Adding water and mineral N resulted in increased CO2 emissions, increased CH4 uptake and decreased NO emissions in elevated CO2 soils. The N addition study confirmed previous observations that soil respiration is enhanced under elevated CO2 and N immobilization is increased, thereby decreasing NO emission.

Responses of the apple plant to CO2 enrichment: changes in photosynthesis, sorbitol, other soluble sugars, and starch

1998 ◽  
Vol 25 (3) ◽  
pp. 293 ◽  
Author(s):  
Q. Pan ◽  
Z. Wang ◽  
B. Quebedeaux
Keyword(s):  
Elevated Co2 ◽  
Soluble Sugars ◽  
Co2 Enrichment ◽  
Carbohydrate Accumulation ◽  
Photosynthetic Rates ◽  
Mature Leaves ◽  
Whole Plant ◽  
Plant Photosynthesis ◽  
Apple Plant ◽  
Ambient Co2

There is no information on the effects of elevated [CO2] on whole-plant photosynthesis and carbohydrate metabolism in apple (Malus domestica Borkh.) and other sorbitol-translocating plants. Experiments were conducted in controlled growth chambers to evaluate how increases in [CO2] affect plant photosynthesis and carbon partitioning into soluble sugars and starch in apple leaves. Apple plants (cv. Gala), 1-year-old, were exposed to [CO2] of 200, 360, 700, 1000, and 1600 µL L-1 up to 8 d. Whole-plant net photosynthetic rates were analysed daily after [CO2] treatments. Newly expanded mature leaves were sampled at 1, 2, 4, and 8 d after [CO2] treatments for sorbitol, sucrose, glucose, fructose, and starch analysis. Midday whole-plant net photosynthetic rates increased linearly with increasing [CO2], but the differences in whole-plant photosynthesis between CO2-enrichment and ambient [CO2] treatments were less significant as apple plants acclimated to high atmospheric [CO2] for 8 d. Increases in [CO2] significantly increased sorbitol and starch, but did not affect sucrose concentrations. As a result, the ratios of starch to sorbitol and starch to sucrose at 8 d after [CO2] treatments were increased from 0.05 and 0.06 to 0.8 and 1.6 as [CO2] increased from ambient [CO2] (360 µL L-1) to 1000 µL L-1 [CO2], respectively. The sorbitol to sucrose ratio also increased from 1.3 to 2.2 as [CO2] increased from 360 to 1000 µL L-1. Elevated [CO2] enhanced the photosynthesis of apple plants and altered carbohydrate accumulation in mature leaves in favour of starch and sorbitol over sucrose.

The Influence of CO2 Enrichment on Growth, Nutrient Content and Biomass Allocation of Maranthes corymbosa

1993 ◽  
Vol 41 (2) ◽  
pp. 195 ◽  
Author(s):  
CA Berryman ◽  
D Eamus ◽  
GA Duff
Keyword(s):  
Elevated Co2 ◽  
Plant Biomass ◽  
Nutrient Use Efficiency ◽  
Co2 Enrichment ◽  
Vapour Pressure Deficit ◽  
Density Fluctuations ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Total Plant ◽  
Use Efficiency

Seedlings of Maranthes corymbosa Blume, an evergreen tree of tropical Australia and Indonesia were grown for 32 weeks under conditions of ambient and elevated (700 μmol CO2 mol-1) CO2 in tropical northern Australia. Seedlings were exposed to ambient temperature, vapour pressure deficit and photon flux density fluctuations. Rates of germination and percentage germination were not affected by elevated CO2. Total plant biomass, height growth, total plant leaf area, numbers of leaves and branches and specific leaf weight were significantly increased by elevated CO2. Root:shoot ratio and foliar P, K, Mg, Mn and Ca levels were unaffected but foliar nitrogen levels were decreased by elevated CO2, Nutrient-use-efficiency was unaffected for phosphorus, magnesium, manganese, calcium and potassium but nitrogen-use-efficiency increased in response to elevated CO2.

Growth Responses on Young Wheat Plants to a Range of Ambient CO2 Levels

1978 ◽  
Vol 5 (1) ◽  
pp. 45 ◽  
Author(s):  
TF Neales ◽  
AO Nicholls
Keyword(s):  
Plant Biomass ◽  
Growth Parameters ◽  
Co2 Enrichment ◽  
Co2 Concentration ◽  
Plant Age ◽  
Growth Responses ◽  
Wheat Seedlings ◽  
Co2 Levels ◽  
Sequential Experiments ◽  
Ambient Co2

The growth of wheat seedlings in a closed environment was measured from day 10 to day 24 after germination, in 12 separate and sequential experiments, in which the imposed variable was the ambient CO2 concentration. CO2 levels between 200 and 800 volumes per million (vpm) and a daily irradiance of 6.5 MJ m-2 were used. The effects of CO2 concentration on various growth parameters strongly interacted with plant age. For instance, in the 10-day-old plants, relative growth rate and net assimilation rate were increased (by 35 and 55% respectively) by an increase in CO2 levels from 200 to 800 vpm, whereas these two growth parameters were reduced (by 44 and 16%) in 24-day-old plants over the same interval of CO2 concentration. Also, increasing CO2 levels reduced the leafiness (leaf area ratio) of the plant, and increased the dry matter in the leaves (specific leaf weight). It is suggested that the observed large interactions on plant growth of plant age and CO2 concentration account for the relatively small enhancement by CO2 enrichment of total plant biomass and economic yield that are reported in the literature.

Characterization of diurnal photosynthetic rhythms in the marine diatom Skeletonema costatum grown in synchronous culture under ambient and elevated CO2

2004 ◽  
Vol 31 (4) ◽  
pp. 399 ◽  
Author(s):  
Xiongwen Chen ◽  
Kunshan Gao
Keyword(s):  
Chlorophyll A ◽  
Elevated Co2 ◽  
Skeletonema Costatum ◽  
Co2 Enrichment ◽  
Light Period ◽  
Marine Diatom ◽  
Initial Slope ◽  
Co2 Uptake ◽  
Chlorophyll A Content ◽  
Ambient Co2

Photosynthetic performance was examined in Skeletonema costatum (Greville) Cleve. under 12 : 12-h light : dark (LD) cycle at ambient CO2 (350 μL L–1) and elevated CO2 (1000 μL L–1). At ambient CO2, the cellular chlorophyll a content, the light-saturated photosynthetic rate (Pm), the initial slope of the light saturation curves (α), the photochemical efficiency of PSII (Fv / Fm), the apparent carboxylating efficiency (ACE) and the photosynthetic affinity for CO2 [1 / Km(CO2)] all showed rhythmical changes with different amplitudes during the light period. The Pm had similar changing pattern in the light period with the ACE and 1 / Km(CO2) rather than with the α and Fv / Fm, indicating that rhythmical changes of photosynthetic capacity may be mainly controlled by the activity of C-reduction associated with CO2 uptake during the light period. The CO2 enrichment reduced the ACE and the affinity to CO2, and increased the α, cellular chlorophyll a content and Pm based on cell number. By contrast, the changing patterns of all photosynthetic parameters examined here during the light period had almost the same for cells grown at ambient CO2 and elevated CO2, suggesting that the photosynthetic rhythms of S. costatum are not affected by CO2 enrichment.

scholarly journals The Effect of Different Nitrogen Levels and Enrichment CO2 on the Nutrient Contents of Rice Cultivars

1970 ◽  
Vol 44 (2) ◽  
pp. 241-246 ◽  
Author(s):  
MA Razzaque ◽  
MM Haque ◽  
QA Khaliq ◽  
ARM Solaiman
Keyword(s):  
Elevated Co2 ◽  
Nitrogen Concentration ◽  
Co2 Enrichment ◽  
Rice Cultivars ◽  
Nutrient Contents ◽  
Plant Parts ◽  
Nitrogen Levels ◽  
Open Field Condition ◽  
Ambient Co2 ◽  
Key Words Rice

An experiment was conducted during the July -December of 2003 to determine the nutrient compositions of rice under CO2 enrichment of different levels of nitrogen supply. Rice plants were grown from seedlings to maturity inside open top chamber under elevated CO2 (570 ±50) ppm, ambient CO2 (~360ppm) and open field condition. Leaves and root were analyzed for C, N, Zn and Mg. C content was higher in the all plant parts of rice grown at elevated CO2 compare than ambient CO2 and field grown rice. Increased N supplies also increase C content of the plants. Nitrogen concentration was reduced in elevated CO2 compare than other grown condition. Modern variety (BRRIdhan 39) contained higher C than local cultivars (Khaskani and Shakkorkhora). Nitrogen concentration was decreased under elevated CO2 compare to other treatments. Key words : Rice cultivars, Enrichment CO2, C, N, Zn, Mg DOI: 10.3329/bjsir.v44i2.3680 Bangladesh J. Sci. Ind. Res. 44(2), 241-246, 2009   

scholarly journals Effects Of CO2 And Nitrogen Levels On Yield And Yield Attributes Of Rice Cultivars

1970 ◽  
Vol 36 (2) ◽  
pp. 213-221 ◽  
Author(s):  
MA Razzaque ◽  
MM Haque ◽  
QA Khaliq ◽  
ARM Soliman ◽  
A Hamid
Keyword(s):  
Elevated Co2 ◽  
Co2 Enrichment ◽  
Rice Cultivars ◽  
Rice Varieties ◽  
Local Varieties ◽  
Yield Attributes ◽  
Nitrogen Levels ◽  
N Level ◽  
Open Field Condition ◽  
Ambient Co2

A pot experiment was conducted at Bangbandhu Sheikh Mujibur Rahman Agricultural University during July–December of 2003 to determine the effect of rice varieties under CO2 enrichment and different levels of nitrogen supply. Plants were grown from seedling to maturity inside open top chamber under elevated CO2 (570 ±50) ppm, ambient CO2 (~360ppm) and open field condition. Cultivars responded considerably under different nitrogen levels. Increasing atmospheric CO2 directly stimulated photoynthesis and plant growth resulting in increased grain yield. Among the cultivars, BRRIdhan 39 gave the highest yield (50.82 g/plant1) at supra optimum N level and elevated CO2. Local varieties gave similar results under elevated CO2 in optimum and supra optimum N level. The lowest yield was produced by the local variety Shakkorkhora (15.09 g) under ambient CO2 with no nitrogen application. Keywords: CO2 enrichment; nitrogen level; rice cultivars DOI: http://dx.doi.org/10.3329/bjar.v36i2.9247 BJAR 2011; 36(2): 213-221

Research note: Can decreased transpiration limit plant nitrogen acquisition in elevated CO2?

2002 ◽  
Vol 29 (9) ◽  
pp. 1115 ◽  
Author(s):  
Evan P. McDonald ◽  
John E. Erickson ◽  
Eric L. Kruger
Keyword(s):  
Stomatal Conductance ◽  
Elevated Co2 ◽  
Plant Biomass ◽  
Stomatal Closure ◽  
Co2 Enrichment ◽  
Root Mass ◽  
N Accumulation ◽  
Plant Nitrogen ◽  
N Concentration ◽  
N Acquisition

N acquisition often lags behind accelerated C gain in plants exposed to CO2-enriched atmospheres. To help resolve the causes of this lag, we considered its possible link with stomatal closure, a common first-order response to elevated CO2 that can decrease transpiration. Specifically, we tested the hypothesis that declines in transpiration, and hence mass flow of soil solution, can decrease delivery of mobile N to the root and thereby limit plant N acquisition. We altered transpiration by manipulating relative humidity (RH) and atmospheric [CO2]. During a 7-d period, we grew potted cottonwood (Populus deltoides Bartr.) trees in humidified (76% RH) and non-humidified (43% RH) glasshouses ventilated with either CO2-enriched or non-enriched air (~1000 vs ~380�μmol mol–1). We monitored effects of elevated humidity and/or CO2 on stomatal conductance, whole-plant transpiration, plant biomass gain, and N accumulation. To facilitate the latter, NO3– enriched in 15N (5 atom%) was added to all pots at the outset of the experiment. Transpiration and 15N accumulation decreased when either CO2 or humidity were elevated. The disparity between N accumulation and accelerated C gain in elevated CO2 led to a 19% decrease in shoot N concentration relative to ambient CO2. Across all treatments, 15N gain was positively correlated with root mass (P&lt;0.0001), and a significant portion of the remaining variation (44%) was positively related to transpiration per unit root mass. At a given humidity, transpiration per unit leaf area was positively related to stomatal conductance. Thus, declines in plant N concentration and/or content under CO2 enrichment may be attributable in part to associated decreases in stomatal conductance and transpiration.

Sink Strength May Be the Key to Growth and Nitrogen Responses in N-Deficient Wheat at Elevated CO2

1996 ◽  
Vol 23 (3) ◽  
pp. 253 ◽  
Author(s):  
GS Rogers ◽  
PJ Milham ◽  
M Gillings ◽  
JP Conroy
Keyword(s):  
Elevated Co2 ◽  
Protein Concentration ◽  
Shoot Growth ◽  
Co2 Enrichment ◽  
Sink Strength ◽  
High Co2 ◽  
N Supply ◽  
N Concentration ◽  
Ambient Co2 ◽  
Leaf N

The influence of elevated CO2 (350, 550 and 900 μL L-1) and N supplies ranging from deficient to excess (0-133 mg N kg-1 soil week-1) on the leaf N concentration and shoot growth of wheat (Triticum aestivum L.), cultivar Hartog, was investigated. Shoot growth was 30 % greater at 550 μL L-1 compared to ambient CO2 at all levels of N supply. When the CO2 concentration was increased to 900 μL L-1, there was no increase in shoot growth at low N supply but it more than doubled at high N supply (67 mg N kg-1 soil week-1). Growth effects were closely matched by changes in sink development, suggesting that sink strength, mediated through N supply controlled the shoot growth response to elevated CO2. The shoot N concentration was lower at each level of CO2 enrichment and the greatest effect (30% reduction) occurred at 900 μL CO2 L-1, 33 mg N kg-1 soil week-1. The effect of high CO2 on shoot N concentration diminished as N supply increased and, at the highest N addition rate, there was only a 7% reduction. Changes in foliar N concentration due to CO2 enrichment were closely correlated with lower soluble protein concentration, accounting for 58 % of the total leaf N reduction. Ribulose- IS-bisphosphate carboxylase/oxygenase (Rubisco) levels were also reduced at high CO2 and N was allocated away from Rubisco and into other soluble proteins at high CO2 when N supply was low. Non- structural carbohydrate concentration (dry weight basis) was greatest at 900 μL CO2 L-1 and low N supply and may have reduced Rubisco concentration via a feed-back response. Critical foliar N concentrations (N concentration at 90 % of maximum shoot growth) were reduced from 43 mg g-1 at ambient CO2 to 39 and 38 mg g-1 at 550 and 900 μL CO2 L-1, respectively. Elevated CO2, at N supplies of 0-17 mg N kg-1 soil week-1, reduced flour protein concentration by 9-13 %.

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