The impact of elevated atmospheric CO2 and nitrate supply on growth, biomass allocation, nitrogen partitioning and N2 fixation of Acacia melanoxylon

1999 ◽  
Vol 26 (8) ◽  
pp. 737 ◽  
Author(s):  
Marcus Schortemeyer ◽  
Owen K. Atkin ◽  
Nola McFarlane ◽  
John R. Evans
Keyword(s):  
Elevated Co2 ◽  
N2 Fixation ◽  
Dry Matter ◽  
Co2 Concentration ◽  
Dry Mass ◽  
Nitrogen Partitioning ◽  
Atmospheric Co2 ◽  
Acacia Melanoxylon ◽  
Nitrate Supply ◽  
The Impact

The interactive effects of nitrate supply and atmospheric CO2 concentration on growth, N2 fixation, dry matter and nitrogen partitioning in the leguminous tree Acacia melanoxylon R.Br. were studied. Seedlings were grown hydroponically in controlled-environment cabinets for 5 weeks at seven 15N-labelled nitrate levels, ranging from 3 to 6400 mmol m–3. Plants were exposed to ambient (~350 µmol mol–1) or elevated (~700 µmol mol–1) atmospheric CO2 for 6 weeks. Total plant dry mass increased strongly with nitrate supply. The proportion of nitrogen derived from air decreased with increasing nitrate supply. Plants grown under either ambient or elevated CO2 fixed the same amount of nitrogen per unit nodule dry mass (16.6 mmol N per g nodule dry mass) regardless of the nitrogen treatment. CO2 concentration had no effect on the relative contribution of N2 fixation to the nitrogen yield of plants. Plants grown with ≥50 mmol m–3 N and elevated CO2 had approximately twice the dry mass of those grown with ambient CO2 after 42 days. The rates of net CO2 assimilation under growth conditions were higher per unit leaf area for plants grown under elevated CO2. Elevated CO2 also decreased specific foliage area, due to an increase in foliage thickness and density. Dry matter partitioning between plant organs was affected by ontogeny and nitrogen status of the plants, but not by CO2 concentration. In contrast, plants grown under elevated CO2 partitioned more of their nitrogen to roots. This could be attributed to reduced nitrogen concentrations in foliage grown under elevated CO2.

scholarly journals Response of simulated burned area to historical changes in environmental and anthropogenic factors: a comparison of seven fire models

2019 ◽  
Vol 16 (19) ◽  
pp. 3883-3910 ◽  
Author(s):  
Lina Teckentrup ◽  
Sandy P. Harrison ◽  
Stijn Hantson ◽  
Angelika Heil ◽  
Joe R. Melton ◽  
...  
Keyword(s):  
Land Use ◽  
Co2 Concentration ◽  
Fire Regimes ◽  
Atmospheric Co2 ◽  
Anthropogenic Factors ◽  
Burned Area ◽  
Earth System ◽  
Atmospheric Co2 Concentration ◽  
Fire Models ◽  
The Impact

Abstract. Understanding how fire regimes change over time is of major importance for understanding their future impact on the Earth system, including society. Large differences in simulated burned area between fire models show that there is substantial uncertainty associated with modelling global change impacts on fire regimes. We draw here on sensitivity simulations made by seven global dynamic vegetation models participating in the Fire Model Intercomparison Project (FireMIP) to understand how differences in models translate into differences in fire regime projections. The sensitivity experiments isolate the impact of the individual drivers on simulated burned area, which are prescribed in the simulations. Specifically these drivers are atmospheric CO2 concentration, population density, land-use change, lightning and climate. The seven models capture spatial patterns in burned area. However, they show considerable differences in the burned area trends since 1921. We analyse the trajectories of differences between the sensitivity and reference simulation to improve our understanding of what drives the global trends in burned area. Where it is possible, we link the inter-model differences to model assumptions. Overall, these analyses reveal that the largest uncertainties in simulating global historical burned area are related to the representation of anthropogenic ignitions and suppression and effects of land use on vegetation and fire. In line with previous studies this highlights the need to improve our understanding and model representation of the relationship between human activities and fire to improve our abilities to model fire within Earth system model applications. Only two models show a strong response to atmospheric CO2 concentration. The effects of changes in atmospheric CO2 concentration on fire are complex and quantitative information of how fuel loads and how flammability changes due to this factor is missing. The response to lightning on global scale is low. The response of burned area to climate is spatially heterogeneous and has a strong inter-annual variation. Climate is therefore likely more important than the other factors for short-term variations and extremes in burned area. This study provides a basis to understand the uncertainties in global fire modelling. Both improvements in process understanding and observational constraints reduce uncertainties in modelling burned area trends.

scholarly journals Development of experimental structure and influence of high CO2 concentration in maize cro

2012 ◽  
Vol 32 (2) ◽  
pp. 306-314 ◽  
Author(s):  
João B. Lopes da Silva ◽  
Paulo A. Ferreira ◽  
Eduardo G. Pereira ◽  
Luís C. Costa ◽  
Glauco V. Miranda
Keyword(s):  
Experimental Design ◽  
Dry Matter ◽  
Co2 Concentration ◽  
Dry Mass ◽  
C4 Plant ◽  
Active Radiation ◽  
High Co2 ◽  
Photosynthetic Rates ◽  
High Co2 Concentration ◽  
Experimental Structure

Maize is a C4 plant that shows few or no response to high [CO2]. Thus, this study aimed to analyze the photosynthetic rate and yield of maize under high [CO2] and develop open-top chambers (OTC) to create an atmosphere enriched with CO2. The experiment was conducted between October 2008 and March 2009. The OTCs were developed in modular scheme. Measurement of photosynthetic rates, transpiration, stomata conductance, grain yield and dry matter were performed. The experimental design was randomized blocks with four replications and three treatments: P1 - plants grown in OTC with 700 ppm [CO2], P2 - plants grown in OTC with environmental [CO2], and P3 - control, cultivated in open field. The results were analyzed by ANOVA and Tukey's test (Pr< 0.05). The chambers can reduce by 25% the photosynthetically active radiation and increase the air and leaf temperatures. Plants under high [CO2] (P1) showed the highest photosynthetic rates and the lowest stomata conductance and transpiration. The total weight of grains (g) and dry mass of shoots (g) showed no increases for P1, despite their higher photosynthetic rates.

scholarly journals Elevated CO2 Concentrations and Water Stress Affect the Ability of Italian Ryegrass to Remediate Herbicides and Enhance its Allelopathic Effect

2019 ◽  
Vol 37 ◽  
Author(s):  
L.P. SILVEIRA ◽  
A.R. FEIJÓ ◽  
C. BENETTI ◽  
J.P. REFATTI ◽  
M.V. FIPKE ◽  
...  
Keyword(s):  
Water Stress ◽  
Elevated Co2 ◽  
Co2 Concentration ◽  
Italian Ryegrass ◽  
Allelopathic Effect ◽  
Irrigated Rice ◽  
Allelopathic Potential ◽  
Co2 Concentrations ◽  
Temporal Persistence ◽  
The Impact

ABSTRACT: The long temporal persistence of select herbicides negatively impacts crops sown in succession to irrigated rice. One way to reduce these compounds in the soil over time is through phytoremediation. However, elevated CO2 concentrations may interfere with the phytoremediation process. Another consequence of climate change is the production of allelopathic compounds by forage species used as remedial agents. This study aimed to evaluate the impact of elevated CO2 concentration and drought stress on the remediation of soil samples contaminated with imazapyr + imazapic herbicides by Italian ryegrass and any subsequential affect on the allelopathic effect of this species. We report that the increasing CO2 decreased the phytoremediation potential of ryegrass. Water stress combined with a CO2 concentration of 700 µmol mol-1 caused increased allelopathy. Overall, these are the first data to indicate a significant effect of higher CO2 levels with respect to both phytoremediation efficacy and allelopathic potential of the plant species used in phytoremediation.

Effects of elevated CO2 concentration and nitrogen addition on the chemical compositions, construction cost, and payback time of subtropical trees in Cd-contaminated mesocosm soil

2021 ◽  
Author(s):  
Xiaowei Zang ◽  
Xianzhen Luo ◽  
Enqing Hou ◽  
Guihua Zhang ◽  
Xiaofeng Zhang ◽  
...  
Keyword(s):  
Growth Rate ◽  
Elevated Co2 ◽  
Photosynthetic Rate ◽  
Tree Species ◽  
Co2 Concentration ◽  
Atmospheric Co2 ◽  
Physiological Characteristics ◽  
Chemical Compositions ◽  
N Addition ◽  
Payback Time

Abstract Rising atmospheric CO2 concentration ([CO2]) and nitrogen (N) deposition are changing plant growth, physiological characteristics, and chemical compositions; however, few studies have explored such impacts in a heavy-metal-contaminated environment. In this study, we conducted an open-top chamber experiment to explore the impacts of two years of elevated atmospheric [CO2] and N addition on the growth, physiological characteristics, and chemical compositions of five subtropical tree species in a cadmium (Cd)-contaminated environment. Results showed that N addition significantly increased concentration of leaf N and protein in five tree species, and also decreased payback time (PBT) and leaf C:N ratios and increased tree relative height growth rate (RGR-H) and basal diameter growth rate (RGR-B) in Liquidambar formosana and Syzygium hainanense. Elevated [CO2] increased leaf maximum photosynthetic rate (Amax) and concentration of total non-structural carbohydrates (TNC) and shortened PBT to offset the negative effect of Cd contamination on RGR-B in A. auriculiformis. The combined effects of elevated [CO2] and N addition did not exceed their separate effects on RGR-H and RGR-B in Castanopsis hystrix and Cinnamomum camphora. N addition significantly increased the concentration of leaf Cd by 162.1% and 338.0%, and plant Cd bio-concentration factor (BCF) by 464% and 861% in C. hystrix, and C. camphora, respectively, compared to Cd addition. Among the five tree species, the decreases in PBT and the increases in Amax, RGR-B, and concentrations of leaf protein in response to N and Cd addition under elevated [CO2] were average higher 86.7% in A. auriculiformis than other species, suggesting that the mitigation of the negative effects of Cd pollution by elevated [CO2] and N addition among five species was species-specific. Overall, we concluded that N addition and elevated [CO2] reduced Cd toxicity, and increased the growth rate in A. auriculiformis, S. hainanense and L. formosana, while maintained the growth rate in C. hystrix, and C. camphora by differently increasing photosynthetic rate, altering the leaf chemical compositions, and shortening PBT.

scholarly journals Climate change and agroecosystems: the effect of elevated atmospheric CO2 and temperature on crop growth, development, and yield

2005 ◽  
Vol 35 (3) ◽  
pp. 730-740 ◽  
Author(s):  
Nereu Augusto Streck
Keyword(s):  
Climate Change ◽  
Crop Yield ◽  
Co2 Concentration ◽  
Crop Growth ◽  
Atmospheric Co2 ◽  
C3 Plants ◽  
Elevated Atmospheric Co2 ◽  
Growth Development ◽  
Carbon Dioxide Co2 ◽  
The Impact

The amount of carbon dioxide (CO2) of the Earth´s atmosphere is increasing, which has the potential of increasing greenhouse effect and air temperature in the future. Plants respond to environment CO2 and temperature. Therefore, climate change may affect agriculture. The purpose of this paper was to review the literature about the impact of a possible increase in atmospheric CO2 concentration and temperature on crop growth, development, and yield. Increasing CO2 concentration increases crop yield once the substrate for photosynthesis and the gradient of CO2 concentration between atmosphere and leaf increase. C3 plants will benefit more than C4 plants at elevated CO2. However, if global warming will take place, an increase in temperature may offset the benefits of increasing CO2 on crop yield.

scholarly journals Pearl millet growth and biochemical alterations determined by mycorrhizal inoculation, water availability and atmospheric CO2 concentration

2015 ◽  
Vol 66 (8) ◽  
pp. 831 ◽  
Author(s):  
Eliseu G. Fabbrin ◽  
Yolanda Gogorcena ◽  
Átila F. Mogor ◽  
Idoia Garmendia ◽  
Nieves Goicoechea
Keyword(s):  
Water Content ◽  
Pearl Millet ◽  
Elevated Co2 ◽  
Biomass Production ◽  
Water Regime ◽  
Soluble Sugars ◽  
Co2 Concentration ◽  
Atmospheric Co2 ◽  
Mycorrhizal Inoculation

Pearl millet (Pennisetum glaucum L.) is an important fodder and is a potential feedstock for fuel ethanol production in dry areas. Our objectives were to assess the effect of elevated CO2 and/or reduced irrigation on biomass production and levels of sugars and proteins in leaves of pearl millet and to test whether mycorrhizal inoculation could modulate the effects of these abiotic factors on growth and metabolism. Results showed that mycorrhizal inoculation and water regime most influenced biomass of shoots and roots; however, their individual effects were dependent on the atmospheric CO2 concentration. At ambient CO2, mycorrhizal inoculation helped to alleviate effects of water deficit on pearl millet without significant decreases in biomass production, which contrasted with the low biomass of mycorrhizal plants under restricted irrigation and elevated CO2. Mycorrhizal inoculation enhanced water content in shoots, whereas reduced irrigation decreased water content in roots. The triple interaction between CO2, arbuscular mycorrhizal fungi (AMF) and water regime significantly affected the total amount of soluble sugars and determined the predominant soluble sugars in leaves. Under optimal irrigation, elevated CO2 increased the proportion of hexoses in pearl millet that was not inoculated with AMF, thus improving the quality of this plant material for bioethanol production. By contrast, elevated CO2 decreased the levels of proteins in leaves, thus limiting the quality of pearl millet as fodder and primary source for cattle feed.

Carbon Di Oxide Fertilization: Effects on Plant Productivity

2017 ◽  
Vol 3 (02) ◽  
pp. 73-77
Author(s):  
Supriya Tiwari ◽  
N. K. Dubey
Keyword(s):  
Climate Change ◽  
Elevated Co2 ◽  
Co2 Concentration ◽  
Plant Productivity ◽  
C4 Plants ◽  
Atmospheric Co2 ◽  
Growth And Yield ◽  
Co2 Fertilization ◽  
Co2 Concentrations ◽  
Fertilization Effect

Increasing Carbon dioxide (CO2) is an important component of global climate change that has drawn the attention of environmentalists worldwide in the last few decades. Besides acting as an important greenhouse gas, it also produces a stimulatory effect, its instantaneous impact being a significant increase in the plant productivity. Atmospheric CO2 levels have linearly increased from approximately 280 parts per million (ppm) during pre-industrial times to the current level of more than 390 ppm. In past few years, anthropogenic activities led to a rapid increase in global CO2 concentration. Current Intergovernmental Panel on Climate Change (IPCC) projection indicates that atmospheric CO2 concentration will increase over this century, reaching 730-1020 ppm by 2100. An increase in global temperature, ranging from 1.1 to 6.4oC depending on global emission scenarios, will accompany the rise in atmospheric CO2. As CO2 acts as a limiting factor in photosynthesis, the immediate effect of increasing atmospheric CO2 is improved plant productivity, a feature commonly termed as “CO2 fertilization”. Variability in crop responses to the elevated CO2 made the agricultural productivity and food security vulnerable to the climate change. Several studies have shown significant CO2 fertilization effect on crop growth and yield. An increase of 30 % in plant growth and yield has been reported when CO2 concentration has been doubled from 330 to 660 ppm. However, the fertilization effect of elevated CO2 is not very much effective in case of C4 plants which already contain a CO2 concentration mechanism, owing to their specific leaf 2 anatomy called kranz anatomy. As a result, yield increments observed in C4plants are comparatively lower than the C3 plants under similar elevated CO2 concentrations. This review discusses the trends and the causes of increasing CO2 concentration in the atmosphere, its effects on the crop productivity and the discrepancies in the response of C3 and C4 plants to increasing CO2 concentrations.

Responses of woody Cerrado species to rising atmospheric CO2 concentration and water stress: gains and losses

2016 ◽  
Vol 43 (12) ◽  
pp. 1183 ◽  
Author(s):  
João Paulo Souza ◽  
Nayara M. J. Melo ◽  
Eduardo G. Pereira ◽  
Alessandro D. Halfeld ◽  
Ingrid N. Gomes ◽  
...  
Keyword(s):  
Water Stress ◽  
Elevated Co2 ◽  
Global Climate ◽  
Net Photosynthesis ◽  
Co2 Concentration ◽  
Atmospheric Co2 ◽  
Ecosystem Functions ◽  
Total Biomass ◽  
High Co2 ◽  
Atmospheric Co2 Concentration

The rise in atmospheric CO2 concentration ([CO2]) has been accompanied by changes in other environmental factors of global climate change, such as drought. Tracking the early growth of plants under changing conditions can determine their ecophysiological adjustments and the consequences for ecosystem functions. This study investigated long-term ecophysiological responses in three woody Cerrado species: Hymenaea stigonocarpa Mart. ex Hayne, Solanum lycocarpum A. St.-Hil. and Tabebuia aurea (Silva Manso) Benth. and Hook. f. ex S. Moore, grown under ambient and elevated [CO2]. Plants were grown for 515 days at ambient (430 mg dm–3) or elevated [CO2] (700 mg dm–3). Some plants were also subjected to water stress to investigate the synergy between atmospheric [CO2] and soil water availability, and its effect on plant growth. All three species showed an increase in maximum net photosynthesis (PN) and chlorophyll index under high [CO2]. Transpiration decreased in some species under high [CO2] despite daily watering and a corresponding increase in water use efficiency was observed. Plants grown under elevated [CO2] and watered daily had greater leaf area and total biomass production than plants under water stress and ambient [CO2]. The high chlorophyll and PN in cerrado plants grown under elevated [CO2] are an investment in light use and capture and higher Rubisco carboxylation rate, respectively. The elevated [CO2] had a positive influence on biomass accumulation in the cerrado species we studied, as predicted for plants under high [CO2]. So, even with water stress, Cerrado species under elevated [CO2] had better growth.

Does atmospheric CO2 concentration influence soil nitrifying bacteria and their activity?

Soil Research ◽  
2008 ◽  
Vol 46 (7) ◽  
pp. 617 ◽  
Author(s):  
Saman Bowatte ◽  
R. Andrew Carran ◽  
Paul C. D. Newton ◽  
Phil Theobald
Keyword(s):  
Principal Component Analysis ◽  
Community Composition ◽  
Elevated Co2 ◽  
Principal Component ◽  
Co2 Concentration ◽  
Component Analysis ◽  
Atmospheric Co2 ◽  
Soil Nitrification ◽  
Nitrification Activity ◽  
Atmospheric Co2 Concentration

Ammonia oxidising bacteria (AOB) are important soil microorganisms that carry out the first step in nitrification, the oxidation of ammonia to nitrite. In this paper we investigated the impact of long-term elevated CO2 on soil nitrification and soil AOB community composition. Soil samples were taken from Hakanoa natural CO2 springs, Kamo, Northland, New Zealand. This site has been exposed to elevated CO2 for several decades. Soils were collected from different points near to CO2-emitting vents where the CO2 concentration at canopy height had been characterised. Nitrification activity was measured using a short-term nitrification assay, and AOB community composition was characterised using polymerase chain reaction and denaturing gradient gel electrophoresis (DGGE). A principal component analysis of the DGGE banding pattern was carried out to identify the effect of CO2 on AOB community composition. Soil nitrification activity was markedly decreased with increasing CO2. The variation in DGGE banding patterns revealed differences in the composition of the soil AOB community that were related to CO2 concentration. Principal component analysis showed that the changes in community composition and nitrifying activity were linked and that these changes were related to atmospheric CO2 concentration.

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