Corn stover is a biogas feedstock capable of enhancing agriculture bioenergy potential. Although the influence of growing conditions on biogas yield of corn stover has been reported, the joint ...effects of water and nitrogen on biogas production potential have not been addressed. A two year experiment (Exp. 1 and Exp. 2) was conducted in Balcarce, Argentina to assess nitrogen supply effects on stover composition and potential methane yield of corn crops grown under contrasting water regimes. Treatments were a combination of two nitrogen fertilization doses (0 and 120 kg ha−1) and two water regimes (irrigated and rainfed). Biomass composition (mass closure procedure) was determined, a BMP test was carried out and first-order kinetic parameters were obtained. Interactive effects of nitrogen and water on stover composition were found. BMP tests showed that the biogas production rate (k) decreased upon irrigation while its response to nitrogen depended on water availability. Nitrogen supply decreased specific biogas potential (Bmax) independently of water availability. Methane yield increased with nitrogen fertilization under irrigation, while it decreased under rainfed conditions. The observed water and nitrogen supply interactive effects on stover yield, methane yield and biomass conversion efficiency highlights the importance of considering the joint effects of multiple factors when trying to assess the effects of the environment on biomass quality for bioenergy purposes.
•Nitrogen supply did not increase corn stover yield in water limited environments.•Nitrogen supply decreased specific biogas potential disregarding water availability.•Water and nitrogen interact in their effects on final methane yield.•Irrigation increased methane yield at any nitrogen status.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Sunflower grain weight and oil content show bilinear response to mean temperature.•Oil content is more sensitive to temperature than other grain components that contribute to grain weight.•Mean ...temperature and intercepted solar radiation exert interactive effects on grain weight.•Mean temperature and intercepted solar radiation exert additive effects on oil content.•Different mechanisms underlay the responses of grain weight and oil content to temperature.
Temperature and solar radiation during grain filling are the main drivers of grain weight and composition in several crops. While significant progress has been done on the effect of solar radiation intercepted by the plants (ISR) on grain weight (GW, mg) and oil content (OC, mg grain−1) of sunflower (Helianthus Annus L.), the effects of temperature on these traits are far from clear. As temperature affects the rate of plant development, increasing temperature would shorten grain filling duration and so, the critical period for ISR effect on GW and OC (indirect effect of temperature). However, direct effects of temperature non-mediated by ISR accumulation could also affect these traits. The objectives of this work were a) to characterize the responses of grain weight and oil content to mean temperature during grain filling in two traditional sunflower hybrids and b) to determine whether these responses can be exclusively explained by changes in ISR or any direct effect of temperature should also be considered. Two experimental approaches have been used to address these objectives: i) temperature manipulation at constant incident radiation in growth chambers; ii) modification of radiation interception in the field in different locations and years (different mean temperatures). Growth chamber experiments showed that GW and OC respond to temperature in a plateau lineal shape. At low incident radiation such as that of growth chambers, temperature effects on GW can be exclusively explained by reductions in ISR, while both direct and indirect effects of MT are evident on OC. Results obtained in field experiments confirmed this behavior at low radiation. Both GW and OC exponentially increased up to a maximum with ISR disregarding MT. Mathematical models were established to describe the responses of GW and OC to MT and ISR. These models consider MT x ISR interactive effects on GW; and MT - ISR additive effects on OC. The combination of growth chamber and field experiments observations allowed to unravel different mechanisms underlying the responses of GW and OC to temperature: at low incident radiation intensity, increasing temperature decreased GW exclusively by reducing ISR accumulation (indirect effects) while at higher radiation, temperature displays both direct (non-mediated by ISR) and indirect (ISR mediated) effects on GW. OC is affected by temperature in both direct and indirect way disregarding ISR. This work constitutes an important contribution towards understanding the effect of temperature during grain filling on sunflower yield and its relationship to solar radiation effects.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
► Thirty-four native-to-Argentina microalgae strains were isolated. ► Novel RNA sequences in the ITS1-5.8S-ITS2 region were reported. ► Some strains accumulated lipids up to 43% of their dry biomass. ...► High ratios of mono-unsaturated to poly-unsaturated fatty acids are shown. ► Strains with doubling times up to 6h were identified.
As part of pioneering efforts to assess the potential of native microalgae as biofuel feedstock in South–Eastern Buenos Aires, 34 monoalgal cultures (corresponding to the Phylum Chlorophyta) were established and 21 were selected for further growth and biomass composition characterization.
Novel RNA sequences in the ITS1-5.8S-ITS2 region were identified. Some strains showed desirable traits as biodiesel feedstock such as (i) apparent maximal doubling times of 6h, (ii) lipids accumulation of up to 43% of their dry biomass, (iii) high ration of mono-unsaturated to poly-unsaturated fatty acids, (iv) high response to CO2 supplementation, and (v) complete sedimentation in 4h. Data of the outdoors performance of some strains suggested they might represent valuable resources for future research towards the regional development of the technology for microalgae-based biofuels.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•Variability of oleic acid percentage was quantified in high oleic sunflower hybrids.•Mean oleic acid percentage and its stability across environments differed among hybrids.•Oleic acid percentage ...was simulated for current and global warming conditions.•Phenology showed low effect on oleic acid percentage.•Stability of oleic acid percentage could still be a concern in a global warming scenario.
High oleic hybrids of sunflower are widely cultivated around the world. The effect of temperature on oleic acid percentage of these hybrids is a concern, since oils with oleic acid percentage above a threshold receive a prime over the regular price. The objective of this work was to identify the main avenues for the genetic improvement of oleic acid percentage of high oleic hybrids of sunflower, both in current and future global warming scenarios. A data set obtained in a trial network allowed to explore the oleic acid percentage response to temperature of high oleic hybrids in the argentine sunflower growing region (between 29 and 38° LS, 46 trials in 15 locations during the period 2005/06–2012/2013). A similar data set was used to evaluate the variability in phenology. Mean values and stability across environments of oleic acid percentage differed among the studied high oleic hybrids. Differences in the parameter values of a sigmoid equation evidenced the variability in the response of oleic acid to temperature. Oleic acid percentage was simulated with a model that included this equation coupled to a phenology module, for different sowing dates and locations with contrasting temperature, under current conditions and a global warming scenario. It was possible to identify a low number of temperatures and field environments useful to reproduce the rankings of hybrids obtained with a wide range of temperatures. This information could be used to phenotype for high oleic percentage with a low number of experiments and reduce the efforts to identify better high oleic genotypes. Simulations show that the maximum oleic acid percentage is currently not attained in 50% of the studied hybrids in some sowing dates, even at the warmest locations, while in a future global warming scenario it would not be attained in 30% of the studied hybrids in the colder locations. Sensitivity analysis was performed for parameters of the sigmoid equation and the phenology module determining when the critical period for fatty acid composition occurs. In both in current and future scenarios, phenology parameters showed a null or low effect on oleic acid percentage. Two parameters of the sigmoid equation showed a significant impact, which differed between current and future scenarios. Simulations suggest that the stability of oleic acid percentage could still be a concern in the future. However, selecting for key parameter values for a given scenario could help to obtain better high oleic hybrids of sunflower.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•There is a critical period for radiation effect on sunflower oil fatty acid composition.•This critical period is between 350 and 450°Cdaf.•Grain filling dynamics empirically support this critical ...period.•Critical periods for radiation and temperature effects on oil quality are different.
The fatty acid composition of sunflower (Helianthus annuus L.) oil closely depends on the environmental conditions during grain filling. Temperature and solar radiation are the main environmental factors driving oil fatty acid composition. Minimum night temperature and intercepted solar radiation per plant (ISR) during grain filling independently affect oleic acid percentage of traditional sunflower oil. Critical period for temperature effect on this trait has been shown to be placed between 100 and 300°C day after flowering (°Cdaf). The period of maximal sensitivity of fatty acid composition to ISR remains unknown. The aim of the present work was to identify the time window of high sensitivity (critical period) of fatty acid composition to ISR of sunflower oil. For this, ISR was modified by shading (50% or 80%) or thinning (50%) field grown sunflower hybrid DK3820 during different periods of grain filling. The timing of maximal sensitivity of fatty acid composition to source variations during post flowering periods was explored and analyzed by two widely used approaches: (i) evaluation of the relative oleic acid percentage under short shading treatments in relation to the control and (ii) window-pane analysis of the response of oleic acid percentage to ISR. The first approach generated differing estimates of the critical period depending on the level of radiation reduction. Using the second approach, a developmental interval during which oleic acid was most sensitive to ISR regardless of the radiation level was determined. The critical period began at 350°Cdaf and ended at 450°Cdaf. The critical period for radiation effect on oleic acid concentration differed from that of the radiation effect on grain weight and oil concentration and from the critical period for temperature effect on oil fatty acid composition. Different critical periods for different traits and specific environmental factors are indicative of the complexity of the interaction between environmental conditions and grain growth and oil synthesis dynamics.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
La aplicación de fitosanitarios debe garantizar un eficiente control de plagas tratando de evitar pérdidas que afecten la salud humana y el ambiente. El objetivo del trabajo fue evaluar el efecto de ...boquillas hidráulicas tipo cono hueco convencional y aire inducido, y el agregado de un adyuvante (aceite vegetal metilado siliconado AMS), sobre la calidad de aplicación de un fungicida (penetración, distribución y homogeneidad) y las pérdidas por endoderivas en canopeos de trigo y soja. En cada cultivo, el diseño experimental fue completamente aleatorizado, con cuatro repeticiones y arreglo factorial boquillas x adyuvante. El espectro de gotas se evaluó con tarjetas sensibles al agua y con azul brillante como trazador dentro del caldo de aplicación. En trigo, el AMS no uniformizó la distribución de las gotas generadas por las boquillas de aire inducido, dado que dependió del estrato considerado dentro del cultivo. Asimismo, si bien el AMS redujo la endoderiva, esta fue independiente del tipo de boquilla. La distribución de las gotas en soja dependió del estrato en el cultivo y no del tipo de boquilla ni del agregado de AMS. Además, el AMS y su combinación con el tipo de boquilla no redujeron la endoderiva en este cultivo.
Grain growth and oil biosynthesis are complex processes that involve various enzymes placed in different sub-cellular compartments of the grain. In order to understand the mechanisms controlling ...grain weight and composition, we need mathematical models capable of simulating the dynamic behavior of the main components of the grain during the grain filling stage. In this paper, we present a non-structured mechanistic kinetic model developed for sunflower grains. The model was first calibrated for sunflower hybrid ACA855. The calibrated model was able to predict the theoretical amount of carbohydrate equivalents allocated to the grain, grain growth and the dynamics of the oil and non-oil fraction, while considering maintenance requirements and leaf senescence. Incorporating into the model the serial-parallel nature of fatty acid biosynthesis permitted a good representation of the kinetics of palmitic, stearic, oleic, and linoleic acids production. A sensitivity analysis showed that the relative influence of input parameters changed along grain development. Grain growth was mostly affected by the specific growth parameter (μ') while fatty acid composition strongly depended on their own maximum specific rate parameters. The model was successfully applied to two additional hybrids (MG2 and DK3820). The proposed model can be the first building block toward the development of a more sophisticated model, capable of predicting the effects of environmental conditions on grain weight and composition, in a comprehensive and quantitative way.
Wheat straw, one of the most abundant agricultural residues worldwide, can be used to produce biogas, which is considered one of the most efficiently produced renewable energies. Wheat grown with the ...dual-purpose of producing food and biogas should display simultaneously high grain and straw yields, low lodging susceptibility and high conversion efficiency of straw into biogas. The aims of this study were to determine the best food-fuel dual-purpose wheat candidates among 36 wheat genotypes-including French, CIMMYT and local (Criollo) germplasm-used in breeding programs in Argentina and to gain some insights into the relationships between key traits relevant for dual-purpose wheat genotypes.
High variability in individual key traits for dual-purpose wheat ideotype has been found. Genotypes of French origin displayed the highest grain yield, and those of CIMMYT origin, the lowest straw yield. Genotypes of Criollo origin showed the highest lodging susceptibility, and French ones, the lowest. Straw yield was positively correlated with grain yield in all genotypes, and negatively correlated with plant height in genotypes of Criollo origin. Straw conversion into biogas was measured in terms of the biogas potential production and kinetic parameters B
(maximum specific biogas production) and k (first-order kinetic constant) were analyzed. All key traits were analyzed together by a principal component analysis. Baguette 31 and SNR Nogal, two genotypes of French origin, showed high grain yield, high-to-very high straw yield, low lodging susceptibility, and moderate-to-high B
and k. Buck Guapo and Buck Baqueano, two genotypes of Criollo origin, displayed good values for grain yield, straw yield and B
and k. However, their high lodging susceptibility precludes their production in shallow soils or high-input systems. Lastly, some old genotypes (e.g. Klein Atlas) harbored a good combination of all key traits and could prove valuable to be included in future breeding programs for dual-purpose wheat.
While none of the genotypes excelled in every key trait, a few candidates showed potential for dual-purpose ideotype, particularly Baguette 31 and SNR Nogal. The challenge lays in gathering all attributes for food and 2G fuel in the same genotype.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
P-ATPases are characterized by the formation of acid-stable phosphorylated intermediates (
EP) during their reaction cycle. We have developed a microscale method to determine
EP that involves the ...phosphorylation of the enzyme using γ-
32PATP and precipitation with TCA; separation of the sample by SDS-PAGE, and measurement of the enzyme protein and
32P-labeled
EP by digital analysis of both the stained gel and its autoradiogram, respectively. The principal advantages of this method over typical procedures (filtration and centrifugation) are the low amount of enzyme required and the substantial decrease in the blank values and data scattering produced by unspecific phosphorylation and nonquantitative recovering of the enzyme. Application of this new method to a purified preparation of the plasma membrane calcium ATPase (PMCA) results in overcoming the difficulties of measuring
EP at high ATP concentrations. A biphasic behavior of the substrate curve for
EP was observed when the study was extended to ATP levels within the physiological range. Since, in principle, the method does not require the use of highly purified preparations, it could be helpful for the study of phosphorylated intermediates especially under conditions in which small amounts of protein are available, e.g., mutated variants of P-ATPases.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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