Impact Of Elevated CO2 Research Articles

Impacts of Elevated CO2 on Growth, Carbohydrate Assimilation and Nutrient Uptake of Elaeis guineesis Jacq Seedlings

Impacts of Elevated CO2 on Growth, Carbohydrate Assimilation and Nutrient Uptake of Elaeis guineesis Jacq Seedlings

The impact of elevated CO2 on acid-soil tolerance of hexaploid wheat (Triticum aestivum L.) genotypes varying in organic anion efflux

It is unclear how elevated CO2 (eCO2) affects the response of crops to soil acidity. This study examined the effect of eCO2 on acid-soil tolerance of hexaploid wheat genotypes that vary in Al3+ resistance due to differences in root efflux of citrate and malate. Three pairs of near-isogenic lines were grown for 24–25 days under ambient CO2 (400 µmol mol-1) and eCO2 (800 µmol mol-1) in acid soils and hydroponics with various Al3+ concentrations. The lines consisted of pairs that differed in alleles of the TaALMT1 and TaMATE1B genes. Plant growth parameters and rhizosphere soil properties were measured. Elevated CO2 increased the slope of negative correlations between root and shoot biomass and Al3+ concentration in the rhizosphere of a line that has an Al3+-sensitive allele of the TaALMT1 gene conditioning malate efflux (ES8), but did not change that of a near-isogenic sister line with an Al3+-resistant TaALMT1 allele (ET8). Elevated CO2 decreased the relative root length and biomass (% of limed soil) of a line that lacked both malate and citrate efflux (Egret), but did not affect lines that possessed either malate or citrate efflux. Elevated CO2 had no effect on either malate or citrate efflux from root tips of Al3+-resistant lines. Elevated CO2 also increased Al3+ concentration and decreased NH4+ concentration in rhizosphere soil, but decreased concentrations of Al and Zn in shoots. Elevated CO2 decreased acid-soil tolerance of Al3+sensitive genotypes but not of Al3+ resistant genotypes. Malate efflux played a dominant role in conferring acid-soil tolerance to hexaploid wheat.

Combined effects of elevated temperature and CO2 enhance threat from low temperature hazard to winter wheat growth in North China

We examined the growth and yield of winter wheat (Triticum aestivum) in response to the predicted elevated CO2 concentration and temperature to determine the mechanism of the combined impacts in North China Plain. An elevated treatment (CO2: 600 μmol mol−1, temperature: +2.5~3.0 °C, ECTI) and a control treatment (ambient CO2 and temperature, CK) were conducted in open-top chambers from October 2013 to June 2016. Post-winter growth stages of winter wheat largely advanced and shifted to a cooler period of nature season under combined impact of elevated CO2 and temperature during the entire growing season. The mean temperature and accumulated photosynthetic active radiations (PAR) over the post-winter growing period in ECTI decreased by 0.8–1.5 °C and 10–13%, respectively compared with that in CK, negatively impacted winter wheat growth. As a result, winter wheat in ECTI suffered from low temperature hazards during critical period of floret development and anthesis and grain number per ear was reduced by 10–31% in the three years. Although 1000-kernel weight in ECTI increased by 8–9% mainly due to elevated CO2, increasing CO2 concentration from 400 to 600 μmol mol−1 throughout the growth stage was not able to offset the adverse effect of warming on winter wheat growth and yield.

Photosynthetic and morphological responses of oak species to temperature and [CO2] increased to levels predicted for 2050

Urban forests are environmentally, climatically, socially and economically important. An understanding of the response of urban trees to future climate change is crucial to the maintenance of urban forests and the ecosystem services they support. We conducted a controlled environment pot-experiment on four-year-old Mediterranean oak species: the evergreen Quercus ilex and the deciduous Quercus cerris, to investigate the combined impact of elevated CO2 and temperature on growth and leaf physiology to levels predicted for 2050 in urban areas of central Italy. Quercus cerris initially increased net-photosynthesis (PN) under elevated 2050 conditions (EC) compared to present ambient conditions (AC), before PN declined, possibly indicative of down-regulation of photosynthetic physiology. Quercus ilex PN was not influenced by EC throughout the 70 days duration of the study. Levels of PN and stomatal conductance (Gs) were generally lower in Q. ilex than Q. cerris. Quercus ilex also reduced Gs during growth at EC. This reduced transpirative water-loss caused a significant increase in the water use efficiency (WUE) of Q. ilex. This reduction in Gs may have been associated with the observed reduction in stomatal density in Q. ilex grown under EC, while the number of stomata on leaves developed under the experimental conditions were unaffected by the EC treatment in Q. cerris. Over the course of the experiment, above (stem dry weight: SDW) and below-ground biomass (root dry weight: RDW) and foliar starch increased in Q. cerris (in both EC and AC equally) but not Q. ilex. Chlorophyll a fluorescence (ChlF); Prompt Fluorescence (PF), Delayed Fluorescence (DF) and Modulated Reflectance (MR) also indicated that a greater resilience of photochemistry to growth under EC was more apparent in Q. ilex than Q. cerris. In particular, the reduction of the quantum yield efficiency (FV/FM) in Q. ilex may also be considered functional to maintain constant PN levels in elevated temperature and [CO2]. The results of this study suggest that Q. ilex exhibits greater plasticity and adaptation to EC, and may therefore perform more favourably under future 2050 climatic conditions.

Impact of elevated CO2 on Nilaparvata lugens (Stal), rice crop and feeding of Pardosa pseudoannulata

Impact of elevated CO₂ on <i>Nilaparvata lugens</i> (Stal), rice crop and feeding of <i>Pardosa pseudoannulata</i>

Elevated CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; Levels Affect Phytochemicals and Nutritional Quality of Food Crops

Rising atmospheric CO2 levels pose many challenges to global climate, thus to all forms of life including plants. The impact of elevated CO2 on plant growth and development and the nutritional quality in relation to major nutrients in many crops has been explored extensively. However, information on the elevated CO2 effects on the health-promoting phytochemicals in food crops is rather limited. Major nutrients in food crops including protein, phosphorus, potassium, calcium, iron, zinc and other micronutrients in many food crops are known to be suppressed at elevated CO2 levels. Elevated CO2 increases carbohydrate accumulation but decreases nitrogen accumulation in plants thus affecting their C-N ratio. A number of studies show that high C-N ratio and nitrogen limiting conditions in plants can result in the accumulation of carbon-based secondary metabolites, many of which are health-promoting phytochemicals and allelochemicals involved in plants’ defense against pathogens and herbivory. Although the results from these studies are variable, it can be concluded that while elevated CO2 is known to suppress the content of major nutrients, it may actually have a favorable impact on the accumulation of carbon-based phytochemicals in food crops.

Interactive effects of CO2 concentrations and Alternaria brassicae (Berk.) Sacc. infection on defense signalling in Brassica juncea (L.) Czern. &amp; Coss.

Elevated CO2 is known to affect plant’s constitutive defense by bringing about changes in its structure and biochemistry. Recently, it has been seen that not only constitutive defense but also induced defense is altered by elevated concentrations of CO2. Phytohormones such as salicylic acid and jasmonic acid play an important role in modulating induced defense of plants. Concentrations of these hormones vary due to elevated CO2 that alter plant-pathogen interactions. While, most of these studies report higher levels of SA, very few have reported increase in JA. These observations have mainly been employed to explain increased susceptibility to herbivory. There are very few reports with reference to fungal pathogens and plant defense signalling under elevated CO2. Keeping this in mind, an experiment was conducted in open top chambers (OTCs) in Department of Botany, University of Delhi to assess the impact of elevated CO2 and pathogen Alternaria brassicae on the levels of JA and SA, their respective signalling pathway and subsequently defense of Brassica juncea plants. Under elevated CO2, the activity of phenylalanine ammonia lyase increased, leading to a concomitant rise in the concentration of total phenols. The constitutive levels of salicylic acid (SA) and jasmonic acid (JA) enhanced. When inoculated with Alternaria brassicae, the CO2 concentrations interacted significantly to influence the concentrations of SA and JA; and transcript levels of downstream genes of defense signalling pathways. Under elevated CO2, on pathogen infection the concentration of SA decreased while that of JA increased. Correspondingly the transcript levels of NPR-1, PR1, PR-2, PR-12 and PR-13 were affected.

Impacts of elevated CO2 on exogenous Bacillus thuringiensis toxins and transgene expression in transgenic rice under different levels of nitrogen

Recent studies have highlighted great challenges of transgene silencing for transgenic plants facing climate change. In order to understand the impacts of elevated CO2 on exogenous Bacillus thuringiensis (Bt) toxins and transgene expression in transgenic rice under different levels of N-fertilizer supply, we investigated the biomass, exogenous Bt toxins, Bt-transgene expression and methylation status in Bt rice exposed to two levels of CO2 concentrations and nitrogen (N) supply (1/8, 1/4, 1/2, 1 and 2 N). It is elucidated that the increased levels of global atmospheric CO2 concentration will trigger up-regulation of Bt toxin expression in transgenic rice, especially with appropriate increase of N fertilizer supply, while, to some extent, the exogenous Bt-transgene expression is reduced at sub-N levels (1/4 and 1/2N), even though the total protein of plant tissues is reduced and the plant growth is restricted. The unpredictable and stochastic occurrence of transgene silencing and epigenetic alternations remains unresolved for most transgenic plants. It is expected that N fertilization supply may promote the expression of transgenic Bt toxin in transgenic Bt rice, particularly under elevated CO2.

The impact of elevated CO2 on Prochlorococcus and microbial interactions with 'helper' bacterium Alteromonas.

Prochlorococcus is a globally important marine cyanobacterium that lacks the gene catalase and relies on 'helper' bacteria such as Alteromonas to remove reactive oxygen species. Increasing atmospheric CO2 decreases the need for carbon concentrating mechanisms and photorespiration in phytoplankton, potentially altering their metabolism and microbial interactions even when carbon is not limiting growth. Here, Prochlorococcus (VOL4, MIT9312) was co-cultured with Alteromonas (strain EZ55) under ambient (400 p.p.m.) and elevated CO2 (800 p.p.m.). Under elevated CO2, Prochlorococcus had a significantly longer lag phase and greater apparent die-offs after transfers suggesting an increase in oxidative stress. Whole-transcriptome analysis of Prochlorococcus revealed decreased expression of the carbon fixation operon, including carboxysome subunits, corresponding with significantly fewer carboxysome structures observed by electron microscopy. Prochlorococcus co-culture responsive gene 1 had significantly increased expression in elevated CO2, potentially indicating a shift in the microbial interaction. Transcriptome analysis of Alteromonas in co-culture with Prochlorococcus revealed decreased expression of the catalase gene, known to be critical in relieving oxidative stress in Prochlorococcus by removing hydrogen peroxide. The decrease in catalase gene expression was corroborated by a significant ~6-fold decrease in removal rates of hydrogen peroxide from co-cultures. These data suggest Prochlorococcus may be more vulnerable to oxidative stress under elevated CO2 in part from a decrease in ecosystem services provided by heterotrophs like Alteromonas. This work highlights the importance of considering microbial interactions in the context of a changing ocean.

Warming has a larger and more persistent effect than elevated CO2 on growing season soil nitrogen availability in a species-rich grassland

The terrestrial biosphere’s ability to capture carbon is dependent upon soil nitrogen (N) availability, which might reduce as CO2 increases, but global warming has the potential to offset CO2 effects. Here we examine the interactive impact of elevated CO2 (eCO2) and warming on soil N availability and transformations in a low-fertility native grassland in Tasmania, Australia. Using ion exchange membranes, we examined soil nitrogen availability during the growing season from 2004 to 2010 in the TasFACE experiment. We also estimated soil N transformation rates using laboratory incubations. Soil N availability varied strongly over time but was more than doubled by experimental warming of 2°C, an impact that was consistent from the fifth year of the experiment to its conclusion. Elevated CO2 reduced soil N availability by ~28%, although this varied strongly over time. Treatment effects on potential N mineralisation also varied strongly from year to year but tended to be reduced by eCO2 and increased by warming. These results suggest that warming should increase soil N availability more strongly than it is suppressed by eCO2 in low fertility grasslands such as this, stimulating terrestrial carbon sinks by preventing eCO2-induced nitrogen limitation of primary productivity.

High temperature stress during flowering and grain filling offsets beneficial impact of elevated CO2 on assimilate partitioning and sink-strength in rice

Elevated [CO2] (e[CO2]) environments have been predicted to improve rice yields under future climate. However, a concomitant rise in temperature could negate e[CO2] impact on plants, presenting a serious challenge for crop improvement. High temperature (HT) stress tolerant NL-44 and high yielding basmati Pusa 1121 rice cultivars, were exposed to e[CO2] (from panicle initiation to maturity) and a combination of e[CO2] + HT (from heading to maturity) using field based open top chambers. Elevated [CO2] significantly increased photosynthesis, seed-set, panicle weight and grain weight across both cultivars, more prominently with Pusa 1121. Conversely, e[CO2] + HT during flowering and early grain filling significantly reduced seed-set and 1000 grain weight, respectively. Averaged across both the cultivars, grain yield was reduced by 18 to 29%. Despite highly positive response with e[CO2], Pusa 1121 exposure to e[CO2] + HT led to significant reduction in seed-set and sink starch metabolism enzymatic activity. Interestingly, NL-44 maintained higher seed-set and resilience with starch metabolism enzymes under e[CO2] + HT exposure. Developing rice cultivars with higher [CO2] responsiveness incorporated with increased tolerance to high temperatures during flowering and grain filling using donors such as NL-44, will minimize the negative impact of heat stress and increase global food productivity, benefiting from [CO2] rich environments.

Decadal analysis of impact of future climate on wheat production in dry Mediterranean environment: A case of Jordan

Different aspects of climate change, such as increased temperature, changed rainfall and higher atmospheric CO2 concentration, all have different effects on crop yields. Process-based crop models are the most widely used tools for estimating future crop yield responses to climate change. We applied APSIM crop simulation model in a dry Mediterranean climate with Jordan as sentinel site to assess impact of climate change on wheat production at decadal level considering two climate change scenarios of representative concentration pathways (RCP) viz., RCP4.5 and RCP8.5. Impact of climatic variables alone was negative on grain yield but this adverse effect was negated when elevated atmospheric CO2 concentrations were also considered in the simulations. Crop cycle of wheat was reduced by a fortnight for RCP4.5 scenario and by a month for RCP8.5 scenario at the approach of end of the century. On an average, a grain yield increase of 5 to 11% in near future i.e., 2010s–2030s decades, 12 to 16% in mid future i.e., 2040s–2060s decades and 9 to 16% in end of century period can be expected for moderate climate change scenario (RCP4.5) and 6 to 15% in near future, 13 to 19% in mid future and 7 to 20% increase in end of century period for a drastic climate change scenario (RCP8.5) based on different soils. Positive impact of elevated CO2 is more pronounced in soils with lower water holding capacity with moderate increase in temperatures. Elevated CO2 had greater positive effect on transpiration use efficiency (TUE) than negative effect of elevated mean temperatures. The change in TUE was in near perfect direct relationship with elevated CO2 levels (R2>0.99) and every 100-ppm atmospheric CO2 increase resulted in TUE increase by 2kgha−1mm−1. Thereby, in this environment yield gains are expected in future and farmers can benefit from growing wheat.

Long-term impact of elevated CO2 on phosphorus fractions varies in three contrasting cropping soils

The long-term effect of elevated CO2 (eCO2) on P biogeochemistry in farming systems is largely unknown. This study compared the effects of eCO2 on P fractions in three contrasting soils after growing crops for seven years. An experiment of free-air-CO2-enrichment (FACE) was conducted with a rotation of wheat, field pea and canola grown in intact cores of Chromosol, Vertosol and Calcarosol under ambient CO2 (aCO2) (390 ± 10 ppm) or eCO2 (550 ± 30 ppm). Crop P removal, soil P fractions and biochemical properties were determined. Elevated CO2 resulted in extra 134, 91 and 93 mg P core−1 removed as grains, compared to aCO2, for Chromosol, Vertosol and Calcarosol, respectively. It decreased the concentration of NaHCO3-extractable inorganic P (by 17–36%), and decreased NaOH-extractable inorganic P by 24% in Chromosol, and 77% in Vertosol but did not affect it in Calcarosol. Elevated CO2 also decreased NaOH-extractable organic P by 20, 12 and 7 mg kg−1 in the three soils, respectively. Furthermore, eCO2 decreased soil organic carbon (by 8.2%) and increased microbial biomass carbon and respiration in Chromosol but not in other two soils. Long-term eCO2 favoured microbial mineralization of organic P in Chromosol and chemical mobilization of non-labile inorganic P in all three soils.

Potassium deficiency impedes elevated carbon dioxide‐induced biomass enhancement in well watered or drought‐stressed bread wheat

AbstractPotassium (K) deficiency reduces photosynthesis and biomass production of crop plants and also renders them vulnerable to drought stress, whereas elevated carbon dioxide (CO2) has a positive effect on photosynthesis and yield and ameliorates the adverse effects of drought stress. This study aimed to characterize the physiological responses of wheat (Triticum aestivum L.) stressed with K deficiency under elevated CO2 and drought conditions. Increased biomass production caused by elevated CO2 as a consequence of increased photosynthesis and water use efficiency was absent in young K‐deficient wheat plants. Shoot K concentration was negatively affected by elevated CO2 particularly under K‐deficient conditions, whereas K content per plant was greatest in plants supplied with adequate K and adequate water. Specific leaf weight was increased as a consequence of carbohydrate accumulation in the source leaves of K‐deficient plants particularly under elevated CO2 and drought stress. Potassium deficiency clearly impeded the impact of elevated CO2 in both well watered as well as drought‐stressed plants. Adequate K fertilization is a prerequisite for efficient harvesting of atmospheric CO2 through increased photosynthesis, decreased transpiration, and increased biomass production under changing atmospheric CO2 and soil moisture conditions.

Research of the Impact of Elevated CO2 on Soil Microbial Diversity

As the most sensitive and active factor, the quantity, type and diversity of soil microbe in high concentration CO2 are very important problem for ecological impact of leakage risk in CCS projects. The pot experiment in carbon dioxide artificial climate chamber was used to simulate different CO2 concentration (from concentration in normal atmosphere to 80000μmol/mol) of CCS leakage and study the effects of microbial diversity in sorghum rhizosphere soil on elevated CO2. According to comparing the DGGE electrophoresis of bacteria in sorghum rhizosphere soil under different CO2 concentration, five kinds of indicator bacteria were selected when the CO2 concentration was at 10000μmol/mol, and the soil bacteria of sorghum planting can be used as evaluation index of CO2 leakage included Brucella suis, Thiohalocapsahalophil, Burkholderia cepacia, Porphyromonas gingivicanis, and Bacteroides intestinalis. The leakage of the CCS project can be evaluated by the identification of soil bacteria of sorghum planting in the future.

The impact of elevated CO2 and water deficit stress on growth and photosynthesis of juvenile cacao (Theobroma cacao L.).

Atmospheric CO2 concentration continues to rise and is predicted to reach approximately 700 ppm by 2100. Some predictions suggest that the dry season in West Africa could be extended with climate change. This study examined the effects of elevated CO2 concentration and water deficit on growth and photosynthesis of juvenile cacao. Light-saturated photosynthesis (Pmax), quantum efficiency, and intrinsic water-use efficiency increased significantly in response to elevated CO2, as did a range of growth and development responses (e.g. leaf area and leaf number), but the magnitude of the increase was dependent on the water treatment. Stomatal index was significantly greater in the elevated CO2 treatment; an atypical response which may be a reflection of the environment in which cacao evolved. This study shows a positive effect of elevated CO2 on juvenile cacao which may help to alleviate some of the negative impacts of water deficit stress.

Impact of elevated CO2 and temperature on quality and biochemical parameters of bell pepper (Capsicum annuum) crop

Experiment was conducted during 2014 and 2015 to study effect of elevated CO2 and temperature on quality and biochemical parameters of bell pepper (Capsicum annuum L.) crop. To carry out experiment there were four conditions, i.e. in three Open Top Chambers, (T1: OTC with elevated CO2550±10 ppm; T2: OTC with elevated temperature 1◦C and elevated CO2550±10 ppm; T3: OTC with ambient temperature and CO2(reference) and T4: natural air and temperature). Pooled data for two years indicated that higher fruit size (40.19 cm2) and average fruit weight (63.06 g/ fruit) was obtained in plants grown under elevated CO2. Elevated CO2 and temperature treatment resulted lower leaf chlorophyll (1 708.71 mg/kg). Higher ascorbic acid content in fruits (159.12 mg/100g) was recorded under elevated CO2 and temperature. Lower total soluble solids were observed under elevated CO2 (4.02°B) while higher under elevated CO2 and temperature (5.39°B). Higher N content (5.73%) was recorded under natural condition and lower under elevated CO2 (4.08%). Higher P (0.39%), K (5.21%) and Mg (0.49%) content was recorded under natural condition and lower values were recorded under elevated CO2 and temperature. Significantly higher Ca content (0.46%) was recorded in elevated CO2 and lowest in natural condition (0.35%). Both elevated temperature and CO2 had significant effects on quality and biochemical parameters in vegetables. These parameters of bell pepper crop were affected negatively by changing climatic conditions, i.e. elevated CO2 and temperature where positive effect of CO2 offset by elevated temperature effect.

Impact of Elevated CO2 on Leaf Gas Exchange, Carbohydrates and Secondary Metabolites Accumulation in Labisia pumila Benth

Aims: The aim of this study was to investigate different levels of CO 2 availability alters total phenolic and flavonoid, total available carbohydrate (TAC) and to determine how elevated CO 2 influences gas exchange of Labisia pumila seedlings. Study Design: The 3-months Labisia pumila seedlings of var Alata, var Pumila and var Lanceolata were put under 1 month to acclimatize in a nursery until ready for the treatment. Carbon dioxide enrichment treatments started when seedlings reached 4 months old by exposing them to three levels of CO 2 , viz., ambient CO 2 (400 µmol/mol), twice ambient (800 µmol/mol) and thrice ambient CO 2 (1200 µmol/mol). The split plot 3 x 3 factorial experiment was designed using randomized complete block design with CO 2 levels being the main plot and varieties as the sub-plot replicated Original Research Article Ibrahim et al.; ARRB, 19(6): 1-16, 2017; Article no.ARRB.36673 2 three times. Place and Duration of Study: Ladang 2, Universiti Putra Malaysia Glasshouse complex between July to November 2011. Methodology: The experiment was conducted for 15 weeks. The measurement of photosynthesis was obtained from a closed infra-red gas analyzer LICOR 6400XT Portable Photosynthesis System (IRGA, Licor Inc., USA). Total phenolics and flavonoid were determined using Follin-Ciocalteau reagent and total available carbohydrate using anthrone reagent. Results: It was found that the treatment effects were contributed by CO 2 levels in all weeks measured in leaf gas exchange properties (Net photosynthesis (A), stomatal conductance (g s), transpiration rate (E), intercellular CO 2 (C i) and Instantaneous water use efficiency, WUE). A combination of increases rates of A and E was responsible for enhancement of WUE by 50% in elevated treatment (800 and 1200 µmol/mol). Total available carbohydrate, total phenolics and flavonoid were also influenced by elevated CO 2 in all weeks of measurement. At end of 15 weeks after treatment (WAT), 44% increase in total available carbohydrate had increased total phenolic and flavonoid by 56% and 149% respectively than ambient treatment. At end of 15 WAT It was found, that the photosynthetic capacity of Labisia pumila was enhanced under elevated CO 2 by significantly have higher maximum electron transfer rate, J max and Rubisco CO 2 fixation capacity V cmax than ambient seedlings. Conclusion: In this work, it was observed that the increase in production of total phenolics and flavonoid in L. pumila might be due to increase in production of total available carbohydrate in the present study. The upregulation of photosynthesis in the present study was supported by enhancement of Maximum electron transfer rate, J max and Rubisco CO 2 fixation capacity V cmax than ambient seedlings that showed this plant has high sink strength to cope with high level of CO 2.

Impact of Elevated CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; on Wheat Growth and Yield under Free Air CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; Enrichment

Impact of elevated CO2 (free air CO2 enrichment) was studied on wheat (Triticum aestivum L. var Kundan) growth, yield and proteome. Elevated CO2 significantly impacted both underground (+24%) and aboveground (+15%) biomass. Grain weight/plant and harvest index were increased by 35% and 11.4%, respectively under high CO2. On the other hand, seed protein content was decreased by 19% under CO2 enrichment while seed starch and soluble sugar contents were increased by 8% and 23%, respectively. Wheat leaf proteomics revealed that 50 proteins were showing differential expression. Twenty proteins were more abundant while 30 were less abundant. Thirty two proteins were identified by MALDI TOF TOF. More abundant proteins were related to defense, photosynthesis, energy metabolism etc. While less abundant proteins were related to glycolysis and gluconeogenesis. Wheat grain proteomics revealed that out of 49 differentially abundant proteins, 24 were more in abundance and 25 were less in abundance in wheat grains under eCO2 condition. Thirty three proteins were identified and functionally characterized. They were found to be involved mainly in carbon metabolism, storage, defence and proteolysis. Gluten proteins are the major component of wheat storage proteins. Our results showed that both high and low molecular weight glutenins were more in eCO2 wheat seeds while there was no change in gliadin evels. This might alter wheat dough strength. Concentration of grain Cr and As was increased at eCO2 while that of Fe, Cu, Zn and Se were found to be decreased. Dynamics of carbon utilization and metabolic abilities of soil microbes under eCO2 were significantly altered. Our study showed that altered wheat seed composition is cause for concern vis-a-vis nutrition and health and for industries which may have implications for agriculturally dominated country like India.

Impact of elevated CO2 in Casuarina equisetifolia rooted stem cuttings inoculated with Frankia

Impact of different levels of elevated CO 2 on the activity of Frankia (Nitrogen-fixing actinomycete) in Casuarina equisetifolia rooted stem cuttings has been studied to understand the relationship between C. equisetifolia, Frankia and CO2. The stem cuttings of C. equietifolia were collected and treated with 2000 ppm of Indole Butyric Acid (IBA) for rooting. Thus vegetative propagated rooted stem cuttings of C. equisetifolia were inoculated with Frankia and placed in the Open top chambers (OTC) with elevated CO2 facilities. These planting stocks were maintained in the OTC for 12 months under different levels of elevated CO2 (ambient control, 600 ppm, 900 ppm). After 12 months, the nodule numbers, bio mass, growth, and photosynthesis of C. equisetifolia rooted stem cuttings inoculated with Frankia were improved under 600 ppm of CO2. The rooted stem cuttings of C. equisetifolia inoculated with Frankia showed a higher number of nodules under 900 ppm of CO2 and cuttings without Frankia inoculation exhibited poor growth. Tissue Nitrogen (N) content was also higher under 900 ppm of CO2 than ambient control and 600 ppm levels. The photosynthetic rate was higher (17.8 μ mol CO2 m−2 s−1) in 900 ppm of CO2 than in 600 ppm (13.2 μ mol CO2 m−2 s−1) and ambient control (8.3 μ mol CO2 m−2 s−1). This study showed that Frankia can improve growth, N fixation and photosynthesis of C. equietifolia rooted stem cuttings under extreme elevated CO2 level conditions (900 ppm).