Article

Grain protein accumulation in relation to grain yield of spring wheat ( Triticum aestivum L.) grown in open-top chambers with different concentrations of ozone, carbon dioxide and water availability

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Abstract

The present investigation was undertaken in order to study the influence of ozone, carbon dioxide and water availability on the relationship between grain protein and grain yield in wheat (Triticum aestivum L.). Results were combined from spring wheat, field grown in 16 different open-top chamber experiments, from four different countries. Protein concentration of the grain was negatively (linear) associated with grain yield. This relationship was symmetrical for yield reductions and yield stimulations, despite the fact that the major cause for increases in yield (elevated carbon dioxide concentrations) was different from that causing crop loss (elevated ozone concentrations). The relationship between off-take (the amount of protein taken away from the farmland per unit area) of grain protein and grain yield was clear and highly consistent, but not linear. Yield loss in relation to the reference used (open-top chamber with non-filtered air) was associated with a larger negative change in protein off-take than the positive change in protein off-take corresponding to a yield increase of the same size. The water treatments used in some of the experiments influenced yield and protein content to a very limited extent. It is concluded from the present study that the change of the grain protein from factors such as ozone and carbon dioxide can be explained largely by a simple relationship between grain protein and grain yield at a certain level of nitrogen availability to the plants.

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... Experiments conducted from the 1980s and onwards have shown that elevated CO 2 (eCO 2 ) typically increases crop production [1][2][3]. Not until the turn of the century it was generally recognized that most crops grown under eCO 2 -with the exception of legumes and C 4 crops -systematically exhibit decreased concentrations of nitrogen (N) and protein [2,[4][5][6]. Moreover, it was recently demonstrated that the concentration of other nutrients are also decreased by eCO 2 , including zinc (Zn) and iron (Fe) which are deficient in the diets of approximately one and two billion people, respectively [7]. ...
... However, the effect was present also in field-grown and freely rooted crops in both open-top chamber [10,15 ] and free-air CO 2 fertilization (FACE) experiments [3,11]. It was also suggested that the effect depended on soil N availability, such that it would be alleviated by increased applications of N fertilizers [5,16]. However, recent studies have showed that N concentrations were equally decreased by eCO 2 in crops receiving low and high inputs of N fertilization [11,17 ] (Pleijel et al., unpublished data). ...
... The commonly observed decline in plant N concentration under eCO 2 has often been interpreted as a 'growth dilution' effect, whereby N acquisition, for some reason, does not keep pace with the CO 2 -induced stimulation of carbohydrate production and growth [5,6,19,20]. However, such an effect cannot explain why crop N concentration is decreased when there is neutral or marginal CO 2 -induced shift in productivity ( Figure 1; [11,18]). ...
Article
Crops grown under elevated CO2 (eCO2) typically exhibit enhanced yields but at the same time decreased nutritional quality. The latter effect has often been explained as a growth dilution phenomenon, but this cannot be the only process involved since crop nutrient concentrations are decreased also when production is unaffected by eCO2. We review the current knowledge on eCO2 effects on crop nutritional quality with focus on the current understanding of the possible mechanisms and processes causing these effects. Emphasis is on crop nitrogen (N) and protein concentrations but effects on other nutrients and how they compare with those on N are also covered.
... and TGW (r = -0.65***). The inverse relationship between protein content and grain yield was found in numerous works in bread wheat (Campbell et al., 1981;Pleijel et al., 1999) and triticale (García del Moral et al., 1995). ...
... This relationship had been encountered in many similar works. Dilution of protein by non-nitrogen compounds in the grain seemed to be the primary cause for the negative association between grain yield and protein content (Pleijel et al., 1999). Conditions that promote leaf senescence during grain growth, such as drought or higher temperatures, favour protein deposition over starch accumulation in the grain (Campbell et al., 1981). ...
Chapter
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– A major problem for durum wheat production in the Mediterranean region is yield fluctuation, as a result of year to year variation in precipitation and heat stress during grain growth. Ten durum wheat cultivars differing in drought resistance were grown during 1998, both under rainfed and irrigated conditions in three sites of southern Spain. Vitreousness was positively correlated with TW (r = 0.48**) and semolina colour (r = 0.46**). An inverse relationship was found between grain yield and protein content. Regression of cultivar mean values of protein content and grain yield showed a negative relationship (r = -0.724***) due probably to dilution of protein by non-nitrogen compounds and reduced starch accumulation in the grain under drought conditions. RESUME – "Relation entre certains caractères de qualité et le rendement du blé dur en conditions du sud de l'Espagne". Le problème majeur qui s'oppose à la production du blé dur dans la région Méditerranéenne est la variation du rendement par suite à la variation entre années des précipitations et des hautes températures pendant la croissance du grain. Dix cultivars de blé dur, différents dans leur résistance à la sécheresse, ont été cultivés pendant l'année 1998, en sec et en irrigué dans trois sites du sud de l'Espagne. Le taux de vitrosité a été positivement corrélé avec le poids spécifique (r = 0,48**) et la couleur de la semoule (r = 0,46**). Un rapport inverse a été trouvé entre le rendement en grain et le contenu en protéine. La régression des valeurs moyennes du contenu en protéine sur celles du rendement en grain a révélé une relation négative (r = -0,724***) entre les deux caractères dû probablement à la dilution des protéines par les composés non azotés et la réduction de l'accumulation de l'amidon dans le grain sous les conditions de sécheresse. Mots-clés : Contenu en protéine, rendement du grain, qualité, blé dur.
... Plants exposed to elevated ozone have also been shown to contain a greater proportion of foliar N than control plants. For example, ozone was found to consistently increase nitrogen concentrations in wheat (Pleijel et al., 1999); increased foliar N often means that leaf litter decays more rapidly. Conversely, Weigt et al. (2012) report a significant decrease in leaf N concentrations in Photo: G Mills European beech (Fagus sylvatica) when exposed to 2 x ambient ozone regimes. ...
... These effects are much less documented (see review by Vandermeiren and Pleijel, in Mills and Harmens, 2011), but are considered to be equally as important as effects on yield quantity. In wheat (Triticum aestivum), the most important effects of ozone include increases in grain protein concentration (but decreases the protein yield per plant or ton of seeds) and results in changes in baking quality (Fuhrer et al., 1992;Pleijel et al., 1999;Piikki et al., 2008;Rudorff et al., 1996;Vandermeiren et al., 1992). The "CHIP" study, covering seven different sites across Europe, reported positive effects of ozone on potato tuber quality by decreasing the content of reducing sugars (i.e. ...
Chapter
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This report provides a synthesis of current knowledge on the effects of ground-level ozone on ecosystem services and biodiversity. Ecosystems provide an array of services upon which humans depend for food, fresh water, climate regulation, aesthetic enjoyment and spiritual fulfilment.The increased global population along with increased standards of living and other socio-political, economic, technological and societal changes, mean that our interventions can have profound negative effects on the quality of the services provided by ecosystems.As well as having a direct impact on human health, ozone pollution also affects human well-being indirectly via effects on ecosystem services and biodiversity.This report provides a review of current knowledge of the impacts of ozone on biodiversity and supporting, provisioning,regulating and cultural services. Included are effects of ozone on primary production, carbon, nutrient and water cycling, air quality, crop and timber production, flowering and pollination, and aesthetics of the natural environment, together with the interactions with climate change. Approaches for valuing the cost of ozone pollution impacts on ecosystem services are also discussed.
... In wheat (Triticum aestivum), the most important effects of ozone include increases in grain protein concentration and changes in baking quality (Fuhrer et al., 1990;Pleijel et al., 1999;Rudorff et al., 1996a;Vandermeiren et al., 1992). Piikki et al. (2008) confirmed that ozone increases grain protein concentration although protein yield per plant or ton of seeds was significantly reduced (see Box 5.1). ...
... Species-specific responses of insect pests to increasing ozone concentrations have been observed (see Fuhrer, 2003). Most studies have related changes in insect performance to changes in foliar concentrations of nitrogen, carbohydrate and phenolics (Pleijel et al., 1999;Heagle et al., 1994;Hummel et al., 1998). In general, in an ...
Chapter
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This report synthesises current knowledge on the effects of the gaseous air pollutant, ozone, on the quantity and quality of crop yield and discusses the implications for food security. Several of the world’s most important staple food crops such as rice, wheat, maize and soybean, which together account for 40% of human calorie intake globally, are sensitive to ozone pollution. For the first time, ozone effects on wheat and tomato yield in Europe have been quantified using the flux-based methodology that takes into account the modifying effect of climate, soil and plant factors on the amount of ozone taken up through leaf pores. This report also summarises current concerns on ozone pollution impacts on food crops in northern Europe, Mediterranean Europe and south Asia, and describes case studies on impacts at the national (UK) and local (Saxony, Germany) scales. Impacts of ozone on food and feed quality are also considered together with a review of ozone impacts on food security within a changing climate. Recommendations are made for future policy aiming to protect crop plants from this “hidden” threat to yield quantity and quality.
... In wheat (Triticum aestivum), the most important effects of ozone include increases in grain protein concentration and changes in baking quality (Fuhrer et al., 1990;Pleijel et al., 1999;Rudorff et al., 1996a;Vandermeiren et al., 1992). Piikki et al. (2008) confirmed that ozone increases grain protein concentration although protein yield per plant or ton of seeds was significantly reduced (see Box 5.1). ...
... Species-specific responses of insect pests to increasing ozone concentrations have been observed (see Fuhrer, 2003). Most studies have related changes in insect performance to changes in foliar concentrations of nitrogen, carbohydrate and phenolics (Pleijel et al., 1999;Heagle et al., 1994;Hummel et al., 1998). In general, in an ...
... An adequate balance between protein and starch in grain is an important quality parameter of wheat flour (Högy and Fangmeier, 2008). The carbohydrate composition in grain is often not significantly affected by e[CO 2 ] (Blumenthal et al., 1996;Pleijel et al., 1999;Rogers et al., 1998), but some studies found increased starch concentration in wheat grains under e[CO 2 ] (Fangmeier et al., 1999;Wu et al., 2004). Here, the concentrations of total starch, amylose and amylopectin was < 10 μm, the diameter of starch granules is lower than 10 μm; 10-45 μm, the diameter of starch granules is between 10 μm and 45 μm; P F , P C and P F×C refers to the Pvalue of generation effect, CO 2 effect and the interaction of CO 2 by generation, respectively. ...
... An inverse relationship between increasing grain yield and decreasing grain protein in wheat has been reported, which benefited the starch-based industries while depressed the protein-based industries in future e[CO 2 ] condition (Högy and Fangmeier, 2008;Pleijel et al., 1999;Rogers et al., 1998). In accordance with this, here negative correlations were found between grain yield and grain protein quality related parameters, such as GMP and total amino acid concentrations. ...
Article
Many studies have focused on the effect of elevated atmospheric CO2 concentration (e[CO2]) on grain yield and quality in wheat within-generation; however, the long-term effect of e[CO2] over multiple generations, which will be the case for crops grown in future climate, has received little attention. The grain yield and quality were investigated in wheat after one generation (F1 harvested in 2014) and four generations (F4 harvested in 2017) grown in ambient CO2 concentration (a[CO2], 400 μmol L-1) and e[CO2] (800 μmol L-1), respectively. It was found that the shoot biomass and grain yield were enhanced by e[CO2], whereas the increases of grain number and shoot biomass were more pronounced in F4 compared with that in F1. The exposure to e[CO2] over four generations caused larger reduction in grain N, K, Ca, protein, GMP and total amino acid concentrations in F4 wheat, though the starch yield were not significantly affected by e[CO2]. The results indicate that multigenerational exposure to e[CO2] could exacerbate grain quality reduction in wheat, and the short-term plant response to e[CO2] would not be capable of predicting long-term response of wheat crops to a future CO2-enriched environment.
... Other abiotic factors have also been shown to influence the protein content and physiology of wheat. The results of 16 open-top chamber experiments aimed at assessing the protein content of spring wheat grown under differing concentrations of CO 2 and ozone have been summarised (Pleijel et al. 1999). Findings showed that increasing ozone pollution, reduced wheat grain yield but increased protein content. ...
... Findings showed that increasing ozone pollution, reduced wheat grain yield but increased protein content. Conversely, when ozone was removed, grain yield increased but the concentration of protein decreased (Pleijel et al. 1999). Additionally, the concentration of soil nitrogen is important for determining the protein content of wheat grain, especially when the plants are grown under elevated CO 2 (Rogers et al. 1996). ...
... Plants exposed to elevated ozone have also been shown to contain a greater proportion of foliar N than control plants. For example, ozone was found to consistently increase nitrogen concentrations in wheat (Pleijel et al., 1999); increased foliar N often means that leaf litter decays more rapidly. Conversely, Weigt et al. (2012) report a significant decrease in leaf N concentrations in Photo: G Mills European beech (Fagus sylvatica) when exposed to 2 x ambient ozone regimes. ...
... These effects are much less documented (see review by Vandermeiren and Pleijel, in Mills and Harmens, 2011), but are considered to be equally as important as effects on yield quantity. In wheat (Triticum aestivum), the most important effects of ozone include increases in grain protein concentration (but decreases the protein yield per plant or ton of seeds) and results in changes in baking quality (Fuhrer et al., 1992;Pleijel et al., 1999;Piikki et al., 2008;Rudorff et al., 1996;Vandermeiren et al., 1992). The "CHIP" study, covering seven different sites across Europe, reported positive effects of ozone on potato tuber quality by decreasing the content of reducing sugars (i.e. ...
Technical Report
Full-text available
In this report we provide a review of the state of current knowledge on the effects of ozone pollution on ecosystem services including consideration of effects on biodiversity. Although considered separately, all of the ecosystem services and underlying processes are interlinked, with for example, ozone impacts on root growth contributing to supporting services (primary productivity), provisioning (crop and timber production), regulating (C sequestration and impacts on climate) and cultural services (reduced growth of sensitive species influencing aesthetic qualities of vegetation), and reducing economic value of products such as crop yield. Until recently, much of the research on ozone impacts has focussed on quantifying effects on ecological processes rather than considering the implications for ecosystem services. This report, for the first time, places current process-based knowledge within the context of ecosystem services and thus reports on the potential for impacts of ozone on ecosystem services and biodiversity. The report has been prepared by the Coordination Centre of the ICP Vegetation, an International Cooperative Programme reporting on air pollution impacts on vegetation to the Working Group on Effects of the Convention on Long-Range Transboundary Air Pollution.
... However, dry matter, ash content, crude fat and carbohydrate content were also positively correlated to yield, but the correlation was not significant (table 2). The significant and negative correlations between grain yield and protein content was reported by Pleijel et al. (1999) in bread wheat, and Garcia del Moral et al. (1995) in triticale. The present study also revealed negative and non-significant correlation between grain yield and protein content. ...
Article
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Acha (Digitaria exillis kippis. Stapf and D. iburua Stapf L) is one of the oldest West African cereal and of great value to the natives. It belongs to the Poaceae (Grass) family. Despite its potentials, Acha has remained a marginal crop. The present study focused on the evaluation of the variable genetic expressions and interrelationship between grain yield and some morphological traits of some Acha accessions. These accessions were collected from farmers in five villages of Bokkos Local Government Area of Plateau State. This work was conducted at the end of the 2019 rainy season at the Federal College of Forestry Jos. Grains were harvested from the experimental field and proximate analysis was conducted for the Ash content, crude fat, crude fibre, protein content, carbohydrate content, moisture content, dry matter content and energy values. Analysis of variance revealed variability among the different accessions and the variability spanned the nutritional composition of Acha. Grain yield was positive and significantly correlated with crude fibre content, while dry matter content, crude ash, crude fat content and carbohydrate content even though were positively correlated, the correlation was not significant. The phenotypic variance was slightly higher than the genotypic variance indicating the influence of environment on these traits. Phenotypic Coefficient of Variance (PCV) was equally higher than the corresponding Genotypic Coefficient of Variance (GCV) for all characters evaluated showing that they all interact to some extent. Broad sense heritability estimate coupled with genetic advance as percent mean was high, for most characters studied indicating that these traits are under the influence of additive gene effect and therefore, can be improved by selection except for grain yield which was low, indicating that selection will not be an appropriate method for improving this trait. Other methods of breeding such as mutagenesis can be used.
... Protein content, wet gluten, damaged starch, water absorption index, and water solubility index of wheat flour The protein and gluten contents of flour samples exposed to ozone for different amounts of time are shown in Table 2. Protein content was affected by ozone treatment as the protein content of wheat and rice increased by ozone treatments (25,26). The wet gluten content of wheat flour with 60 min of ozone treatment was the lowest among the samples. ...
Article
The objective of this study was to investigate the effects of ozone treatment on the physicochemical properties of Korean wheat flour. Wheat flour samples were treated with ozone gas at 120 ppm for 15, 30, 45, and 60 min. Color b value, pH, and mold of flour decreased as exposure time to ozone increased. The water absorption index, peak viscosity, and final viscosity of flour increased by ozone treatment. Photomicrographs of flour suspensions under polarized light showed granules tended to lose birefringence owing to ozone during swelling. The result of SDS-PAGE showed that the intensity of protein bands at low molecular weights slightly increased in ozone-treated flours compared to the intensity in the control flour. The results of this study showed ozone gas affected the starch and protein of wheat flour, suggesting a need for further investigation on structural changes in starch and protein by ozone.
... This relationship is a consequence of interactions between nitrogen and carbon metabolism, which finally affect GPC or GY respectively [77]. In wheat, a large proportion of the final grain yield is derived from post-anthesis assimilation and translocation of metabolites, particularly C and N [112]. Thirdly, GPC is largely dependent on the additional provision of nitrogen fertilizer, optimization of N management and selecting cultivars with high N uptake and utilization efficiency [79,[113][114][115]. ...
Article
Full-text available
Wheat leaf senescence is a developmental process that involves expressional changes in thousands of genes that ultimately impact grain protein content (GPC), grain yield (GY), and nitrogen use efficiency. The onset and rate of senescence are strongly influenced by plant hormones and environmental factors e.g. nitrogen availability. At maturity, decrease in nitrogen uptake could enhance N remobilization from leaves and stem to grain, eventually leading to leaf senescence. Early senescence is related to high GPC and somewhat low yield whereas late senescence is often related to high yield and somewhat low GPC. Early or late senescence is principally regulated by up and down-regulation of senescence associated genes. Integration of external and internal factors together with genotypic variation influence senescence associated genes in a developmental age dependent manner. Although regulation of genes involved in senescence has been studied in rice, Arabidopsis, maize, and currently in wheat, there are genotype-specific variations yet to explore. A major effort is needed to understand the interaction of positive and negative senescence regulators in determining the onset of senescence. In wheat, increasing attention has been paid to understand the role of positive senescence regulator, e.g. GPC-1, regulated gene network during early senescence time course. Recently, gene regulatory network involved early to late senescence time course revealed important senescence regulators. However, the known negative senescence regulator TaNAC-S gene has not been extensively studied in wheat and little is known about its value in breeding. Existing data on senescence-related transcriptome studies and gene regulatory network could effectively be used for functional study in developing nitrogen efficient wheat varieties.
... As per the studies based on agronomy, yield, and nutritional quality are of utmost importance, but less attention has been made towards nutritional quality as compared to yield (Ashmore, 2005). For example in wheat, the most important effects of ozone is increasing in grain protein concentration and changes in baking quality (Fuhrer et al., 1990;Pleijel et al., 1999;Rudorff et al., 1996a;Vandermeiren et al., 1992). Ozone increases grain protein concentration although protein yield per plant or ton of seeds was significantly reduced (Piikki et al. 2008). ...
Chapter
Full-text available
Air pollution is a widely known problem which can have significant effects on plant health. In this regard, pollutants such as air particulates, ozone, nitrogen oxides, sulphur dioxides have a negative impact on plant physiology and morphology. Recently, it has been noticed that most of the plant species are affected by tropospheric ozone and particulate matter, especially in developing countries which largely cover the tropical belt. Tropospheric ozone is a major phytotoxic agent because of its reactive nature and that it can actively participate in the mechanism of reactive oxygen species formation. There is strong evidence that indicates ozone as perhaps the biggest air pollution threat to food production. The atmospheric particulate matter is a key indicator of air pollution. It is injected into the air by a variety of natural and anthropogenic sources. Alkaline dust may cause leaf surface injuries. Deposition of such PM may affect rhizosphere which provides more probable route for metabolic uptake of nutrients and impact on vegetation and ecosystem. Since interactions of particulate matter with other pollutants and with the climate change components is an important area for research for the further understanding of ecosystem sustainability. The present chapter discusses the effects of these important pollutants on plants.
... As per the studies based on agronomy, yield, and nutritional quality are of utmost importance, but less attention has been made towards nutritional quality as compared to yield (Ashmore, 2005). For example in wheat, the most important effects of ozone is increasing in grain protein concentration and changes in baking quality ( Fuhrer et al., 1990;Pleijel et al., 1999;Rudorff et al., 1996a;Vandermeiren et al., 1992). Ozone increases grain protein concentration although protein yield per plant or ton of seeds was significantly reduced ( Piikki et al. 2008). ...
Chapter
Full-text available
Global plant productivity is struggling against multifaceted emerging environmental stressors. Future food security strongly depends on the ability to minimize and manage the stresses on crops and trees. A significant development has been made in understanding of plant’s responses under different stresses and how they can be controlled with the use of plant growth regulators, particularly thegrowth hormones. Our improving understanding of plant hormones also increase the chances that plants can be genetically modified to enhance their tolerance towards diverse environmental stresses. In this chapter, we present an overview of abscisic acid, an important plant growth regulator, and how it can provide a possible strategy to increase plant adaptability to future increases in temperatures and soil contamination.
... Excess watering reduced glutenins, high molecular weight (HMW) glutenins and the ratio of HMW to low molecular weight (LMW) glutenin subunits [40,41]. The lower protein content in wheat grains as a result of irrigation is caused by yield dilution effects on grain protein [42,43]. However, in the present study, protein content was not significantly different in wheat grains in the three irrigation treatments, although irrigation significantly improved grain yield and the ratio of EAA/TAA in 2013/2014 (Tables 2 and 3). ...
Article
Full-text available
Water management and nitrogen application are critical factors in wheat grain yield and protein quality. This study aimed to evaluate the effect of irrigation and nitrogen application on the grain yield, protein content and amino acid composition of winter wheat. Field experiments were conducted in a split-plot design with three replications in high-yielding land on the North China Plain in 2012/2013, 2013/2014 and 2014/2015. Three irrigation treatments were examined in main plots: no irrigation, irrigation at jointing, and irrigation at jointing plus anthesis, while subplots were assigned to nitrogen treatment at four different rates: 0, 180, 240, 300 kg N ha⁻¹, respectively. The results indicated that irrigation at jointing and at jointing plus anthesis improved grain yield by an average of 12.79 and 18.65% across three cropping seasons, respectively, compared with no irrigation. However, different irrigation treatments had no significant effect on grain protein content in any cropping season. Compared with no N treatment, 180, 240, and 300 kg N ha⁻¹ N application significantly increased grain yield, by 58.66, 61.26 and 63.42% respectively, averaged over three cropping seasons. Grain protein and the total, essential and non-essential amino acid content significantly increased with increasing nitrogen application. Irrigation significantly improved the essential amino acid index (EAAI) and protein-digestibility-corrected amino acid score (PDCAAS) compared with no irrigation; however, N application decreased them by an average of 7.68 and 11.18% across three cropping seasons, respectively. EAAI and PDCAAS were positively correlated, however, they were highly negatively correlated with yield and grain protein content.
... In addition to its effect on crop yield, O 3 may affect yield quality. For example, Pleijel et al. (1999) reported that grain nitrogen concentration generally increased with increasing O 3 leading to a better baking quality of the flour in spring wheat. However, increasing O 3 had a negative impact on tuber quality of potato . ...
Chapter
Physiology-based crop simulation models have become a key tool in extrapolating the impact of climate change from limited experimental evidence to broader climatic zones, soil types, crop management regimens, crops and climate change scenarios. While these models are a simplification of the reality, they allow a first assessment of the complexity of climate change impact in agriculture. They are playing an increasingly important role in assisting agriculture to adapt to climate change. This includes the use of modeling to optimize management practices, assist in breeding programs, develop new crop rotations and maximize the value of seasonal climate forecasts. In order to meet the increasing demand for assessment of climate change impact, crop models need to be further improved and tested with climate change scenarios involving various changes in ambient temperature and CO2 concentration. Current knowledge gaps include limited understanding and modeling of the interactive impact of climate factors, the impact of extreme events (e.g. heat stress, frost and excess water) occurring at different crop stages, sink-source relationships, and changes in yield quality of crops under future climates. Despite these knowledge gaps, crop models have improved our understanding of the impacts of climate change on many aspects of local and world food production. They have facilitated establishment of new hypotheses for climate change studies, stimulated investigations into climate change adaptation, and assisted in communicating to the public and policy makers that continued climate change could have devastating impacts on food supply.
... As per the studies based on agronomy, yield, and nutritional quality are of utmost importance, but less attention has been made towards nutritional quality as compared to yield (Ashmore, 2005). For example in wheat, the most important effects of ozone is increasing in grain protein concentration and changes in baking quality (Fuhrer et al., 1990; Pleijel et al., 1999; Rudorff et al., 1996a; Vandermeiren et al., 1992). Ozone increases grain protein concentration although protein yield per plant or ton of seeds was significantly reduced (Piikki et al. 2008). ...
Book
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Access to adequate food and nutrition is a fundamental human right. However, a significant population worldwide presently suffers from malnutrition and inadequate access to food. To meet the goal of zero hunger and malnutrition, agricultural production must maintain pace with increasing food demand. This goal is being challenged by rapidly changing socio-economic and environmental issues. Climate change, depleting soil and water resources, air, water and soil pollution are not only reducing productivity, but also pose a threat to food safety and nutrition. This book analyzes linkages between agriculture and environmental changes, major challenges and potential solutions to secure future food security. It covers, in detail, the impacts of major environmental changes including climate change and air pollution on crops and agricultural production. The potential solutions to address these challenges are also discussed. This book provides the reader with a broad view of interactions between agriculture and the environment, where agriculture is not only vulnerable but also acts as a contributor and offers mitigation options for some of the challenges in sustaining future food security. Agricultural sustainability in near and long-term future will depend on adapting crops and crop management practices based on emerging scientific knowledge of plant physiology and resource efficient technologies combined with focused socio-economic reforms to conserve food diversity and traditional practices. With the help of specific case studies, this book also highlights the significance of reforming small scale farming practices. Overall, this book provides the core idea of sustainable agriculture and food production in current and future scenarios, and is recommended for anyone interested in this topic. (Imprint: Nova)
... Pleijel et al. [78] reported a negative linear correlation between grain yield and grain protein concentration in wheat exposed to different concentrations of ozone and carbon dioxide across different countries. Using meta-analysis, Rotundo and Westgate [79] analyzed the environmental effects on metabolite contents and concentrations in soybean seeds. ...
Article
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Vegetable oil utilization is determined by its fatty acid composition. In soybean and other grain crops, during the seed development oil accumulation is important trait for value in food or industrial applications. Seed development is relatively short and sensitive to unfavorable abiotic conditions. These stresses can lead to a numerous undesirable qualitative as well as quantitative changes in fatty acid production. Fatty acid manipulation which targets a higher content of a specific single fatty acid for food or industrial application has gained more attention. Despite several successes in modifying the ratio of endogenous fatty acids in most domesticated oilseed crops, numerous obstacles in FA manipulation of seed maturation are yet to be overcome. Remarkably, connections with plant hormones have not been well studied despite their critical roles in the regulation and promotion of a plethora of processes in plant growth and development. While activities of phytohormones during the reproductive phase have been partially clarified in seed physiology, the biological role of plant hormones in oil accumulation during seed development has not been investigated. In this review seed development and numerous effects of abiotic stresses are discussed. After describing fatty acid and phytohormone metabolism and their interactions, we postulate that the endogenous plant hormones play important roles in fatty acid production in soybean seeds.
... Some of the quality changes found in this study were reported earlier in ozone studies on different rice genotypes and other cereal crops, such as increases in protein concentration despite decreases in protein yield, decreases in starch concentration and increases in grain chalkiness (Frei et al., 2012;Pleijel et al., 1999;Wang and Frei, 2011;Wang et al., 2012. In this study we went one step further to investigate the effects of ozone on protein fractions and amino acid composition. ...
... In addition to its effect on crop yield, O 3 affects yield quality. For example, Pleijel et al. (1999) reported that grain N concentration generally increased with increasing O 3 , leading to a better baking quality of the fl our in spring wheat. However, increasing O 3 had a negative impact on the tuber quality of potato . ...
Chapter
This chapter focuses on crop models, which consider the various aspects of climate change as drivers and capture the main crop physiological functions and other bio-physical aspects of crop–soil–atmosphere systems to address production and natural resource management issues at a paddock level. Physiology-based crop simulation models have been a key tool in extrapolating the impact of climate change from limited climate change-related field and controlled experiments to other climatic zones, soils, management regimes, crops, and climate change scenarios. The impact of the individual climate change components and the combined effect of climate change scenarios on crop production and externalities are explored in the chapter with such models. To counteract negative impacts of climate change and to capture some of the new opportunities of these changes, management options are investigated. Breeding options have received much less attention. While these models are a simplification of the reality, they allow a first assessment of the complexity of climate change impact and adaptation options in agriculture.
... As a consequence of the CO 2 -induced modifications in plant metabolism, grain protein concentration is generally decreased in FACE ex- periments TAUB et al., 2008). Overall, the grain protein concentration is negatively related to grain yield (EVANS, 1993;PLEIJEL et al., 1999), but this is not simply caused by dilution due to increased concentrations of non-protein components ( GIFFORD et al., 2000). Currently, the mechanisms by which CO 2 enrichment decreases proteins are not well understood. ...
Article
To identify future impacts on biomass production and yield quality of important C3 crops, spring wheat was grown in association with 13 weed species in a Mini-FACE (free-air carbon dioxide (CO2) enrichment) system under ambient (375 μl l-1) and elevated (526 μl l-1) CO2 concentrations. Wheat productivity was assessed at maturity and grain yield was subjected to various chemical analyses and baking quality tests. CO2 enrichment acted as carbon ‘fertiliser’ and increased the aboveground biomass production of wheat by 18.8% as there was a trend towards higher stem biomass. Although not statistically significant, wheat grain yield was increased by 13.4% due to a significant establishment of more grains per unit ground area. At the same time, thousand grain weight was non-significantly shifted towards smaller grain size classes, which may result in negative consequences for the crop market value. As a result of the CO2- induced physiological and biochemical modifications, concentration of total grain protein was significantly decreased by 3.5%, reducing the wheat grain quality with potentially far-reaching impacts on the nutritional value and use for processing industry. Although often not significant, the concentrations of amino acids per unit of flour were decreased by 0.2 to 8.3% due to elevated CO2 thereby affecting the composition of proteinogenic amino acids. Furthermore, gluten proteins tended to decline. Within the significant decreased gliadins, α- and ω5-gliadins were significantly reduced under CO2 enrichment; there was also a negative trend for ω1,2- and γ-gliadins. Changes in certain essential minerals were found as well, although not statistically significant. Concentrations of sodium, calcium, phosphorus and sulphur were slightly lowered and those of potassium and magnesium were slightly increased due to CO2 enrichment. The micro-element molybdenum was increased, while concentrations of iron, zinc, copper, manganese and aluminium were decreased. With regard to rheological and baking parameters defining the cereal quality for industrial processing, the resistance of the dough was significantly reduced by about 30%, while the extensibility was non-significantly increased by 17.1% under CO2 enrichment. Moreover, the bread volume was decreased non-significantly by about 9%. Elevated CO2 is obviously affecting grain characteristics important for consumer nutrition and health, industrial processing and marketing. Experimental evidence for these changes is still poor but deserves further attention.
... Ainsi, les facteurs ayant potentiellement un impact positif sur l'assimilation du carbone (augmentation de la concentration en CO 2 , rayonnement incident) entraînent une baisse de la concentration en azote du grain telle que prédite par la relation négative teneur en protéines -rendement en grains(Pleijel et al., 1999). A l'inverse, ceux favorisant une diminution de la durée du remplissage (déficit hydrique et température élevée après floraison) diminuent le rendement à l'échelle du mètre carré, du fait d'une diminution de la matière sèche des grains, et augmentent la concentration en azote. ...
Article
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Grain yield (GY) and grain protein concentration (GPC) are two major targets in wheat breeding programs as these traits contribute to the economic value of the wheat crop. Unfortunately, their simultaneous improvement is hampered by the genetic negative GPC-GY relationship. It has been shown that the deviation to this relationship ("Grain Protein Deviation", GPD) has a genetic basis and might be useful to shift this negative relationship but its biological bases remain unclear. GPD was shown to be mainly related to the genetic variability for post-anthesis nitrogen (N) uptake (PANU) in the North-West European agro-climatic conditions. We proposed that the genetic variability for the access to N in the soil (root architecture and functioning) or for the regulation of PANU by the plant N status (N transport and assimilation) could explain GPD. As delaying leaf senescence during the post-anthesis period might result in increasing PANU, we analysed the genetic determinants of the phenotypic relationships between leaf senescence duration after anthesis and GPC or GY using data obtained on a wheat mapping population grown in a large mutli-environment trial network. A positive association was found between leaf senescence duration and GPC or GY depending onthe environment. We suggested that the impact of delaying leaf senescence after anthesis on GY or GPC might be modulated by the N availability during the post-anthesis period and would lead to modify the GPC-GY relationship depending on the considered environments. Finally, data obtained on three connected mapping populations grown in a large mutli-environment trial network were used to suggest by meta-QTL analysis potential genomic regions possibly useful in wheat breeding to improve GPC without reducing GY. This put forward genomic regions located on the 2A and 3B chromosomes as potentially interesting targets to improve GPC. In particular, the region on the 2A might be related to a chloroplastic glutamine synthetase gene previously shown to be associated with genetic variability for GPC in bread wheat.
... In this study we preferred to summarize this effect in a thermal shock indicator (VART). From grain-filling until maturity a thermal regime above the average can foster an increase of total grain protein and reduce the specific weight of grains, especially when heat stress occurs in conjunction with drought stress (Blumenthal et al., 1995; Gibson and Paulsen 1999; Pleijel et al., 1999; Jamieson et al., 2001; Daniel and Triboï 2002; Flagella et al., 2010 ). Based on these results, the TP 1 model succeeded adequately in reconstructing the GPC temporal variability for the study period and areas (Fig. 2a andFig. ...
... As such, protein deposition may be favoured over starch accumulation in the grain. This is because the production and translocation of carbohydrates to the grain is more sensitive to ozone than protein accumulation (Pleijel et al., 1999) and results in seeds grown under ozone stress tending to have a protein content that is less diluted by carbohydrate accumulation, resulting in the often observed increase of grain protein concentration (Pleijel and Uddling, 2012). However, the absolute amount of protein produced (also known as the "protein yield") is reduced by ozone, but to a lesser extent than biomass. ...
Article
We review current knowledge of the processes by which ozone will cause injury and damage in crop plants. We do this both through an understanding of the limitations to ozone uptake (i.e. ozone being transferred from some height in the atmosphere to the leaf boundary layer and subsequent uptake via the stomata) as well as through the internal plant processes that will result in damage and /or injury. We consider these processes across the range of scales that are impacted in the plant, from cellular injury and damage (that can result in visible injury and alterations to photosynthesis and stomatal conductance) through to leaf level impacts on physiology and leaf senescence and ultimately to alterations in whole plant canopy and root systems that will affect biogeochemical cycling within the plant. We consider these processes from the viewpoint of developing crop growth models that are capable of incorporating key ozone impact processes within modelling structures that asses crop growth under a variety of different stresses. This would provide a dynamic assessment of the impact of ozone on crop growth within the context of other key variables considered important in determining crop growth and yield. We consider the ability to achieve this through an assessment of the different types of crop model (e.g. empirical, radiation use efficiency, and photosynthesis based crop growth models. Finally, we show how international activities such as the AgMIP (Agricultural Modelling and Improvement Intercomparison Project) could provide a network of crop growth modellers to assess the capabilities of different crop models to simulate the effects of ozone and other stresses to improve future regional and global risk assessments.
... The negative coefficients for grain yield components suggested that the dilution of Zn and Fe in grain was due to combined effect of grain size and the number of grains pot −1 (sink size) as indicated by Sperotto et al. (2013) in rice plant, pointing involvement of factors other than grain (sink strength) only. Other factors could be the availability of metals (Marschner, 1995), for instance, Zn and Fe during grain filling (Cakmak et al., 2004Kutman et al., 2011) or factors contributing dry weight (starch) in grain, which increases the size, and weight of grain (Marschner, 1995;Pleijel et al., 1999). ...
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Nearly half of the world cereal production comes from soils low or marginal in plant available zinc, leading to unsustainable and poor quality grain production. Therefore, the effects of nitrogen (N) rate and application time on zinc (Zn) and iron (Fe) concentration in wheat grain were investigated. Wheat (Triticum aestivum var. Krabat) was grown in a growth chamber with 8 and 16 hours of day and night periods, respectively. The N rates were 29, 43 and 57 mg N kg-1 soil, equivalent to 80, 120 and 160 kg N ha- 1. Zinc and Fe were applied at 10 mg kg-1 soil. In one of the N treatments, additional Zn and Fe through foliar spray was applied. Micro-analytical localization of Zn and Fe within grain was performed using scanning macro-X-ray fluorescence (MA-XRF) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). The following data were obtained: grain and straw yield pot-1, 1000 grains weight, number of grains pot-1, whole grain protein content,concentration of Zn and Fe in the grains. Grain yield increased from 80 to 120 kg N ha-1 rates only and decreased at 160 kg N ha- 1 g. Relatively higher protein content and Zn and Fe concentration in the grain were recorded with the split N application of 160 kg N ha-1. Soil and foliar supply of Zn and Fe (Zn+Fes+f), with a single application of 120 kg N ha-1 N at sowing, increased the concentration of Zn by 46% and of Fe by 35%, as compared to their soil application only. Line scans of freshly cut areas of sliced grains showed co-localization of Zn and Fe within germ, crease and aleurone. We thus conclude that split application of N at 160 kg ha-1 at sowing and stem elongation, in combination with soil and foliar application of Zn and Fe, can be a good agricultural practice to enhance protein content and the Zn and Fe concentration in grain.
... Moisture content had negative correlation with chlorophyll a, chlorophyll b and carotenoid content in all the cuttings, except in II nd cutting suggesting that increase in moisture leads to decrease in these quality traits. There are reports of the existence of a negative genetic correlation between yield and quality components in forage grasses (Wilkins and Humphreys, 2003;Annicchiarico and Romani, 2005) as well as in cereals (Jenner et al., 1991;Pleijel et al., 1999). It was interesting to note that carotenoid, protein and ascorbic acid had significant positive association with foliage yield only in the I st cutting when yield was minimum. ...
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A two-year study was conducted to evaluate the foliage yield potential in 13 germplasm lines of Chenopodium album for 3 successive cuttings. Correlations among foliage yield and its contributing traits, along with path analysis was also worked out. Foliage yield was maximum for C. album IC 107297, followed by C. album H.P. and C. album amaranticolor. The genotype × year interaction was non-significant for all the traits except stem diameter and moisture content. Leaf size, plant height and stem diameter showed significant positive correlation with foliage yield both at phenotypic and genotypic levels in all the cuttings. Chlorophyll a and chlorophyll b showed positive association with carotenoid content and negative association with ascorbic acid in all the cuttings as well as on pooled basis. Significant negative association was observed between leaves/plant and foliage yield at genotypic level in all the cuttings (I st cutting:-0.472*; II nd cutting:-0.414*; III rd cutting:-0.480*) as well as on pooled basis (-0.591**). Protein content negatively affected foliage yield in all the cuttings. Fibre content had high negative value of direct path for pooled data but positively influenced foliage yield indirectly via leaves/plant, stem diameter, chlorophyll a, chlorophyll b and protein content. Ascorbic acid positively affected yield in I st cutting as well as on pooled basis. Leaf size had high positive direct effect and significant positive association with foliage yield that indicates a true relationship between these traits. Leaf size also indirectly affected foliage yield in a positive direction through majority of other traits. Thus, direct selection for leaf size should be exercised to bring about improvement in foliage yield in C. album.
... Similarly, [45] reported increased protein content of wheat with high moisture stress and nitrogen fertilization. Reference [46] also noticed in their work that soil moisture more strongly influenced the nitrogen content of wheat grain than available nitrogen in the soil. The low protein content in wheat grains as a result of high moisture content (T6) was caused by yield dilution effects on grain protein [47]. ...
Article
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Global wheat demand is expected to continue to increase due to the projected increase in the World’s population but regrettably, wheat yield is expected to decrease due to the progressively changing climate. Although the effects of temperature, soil moisture and nutrient absorption on the yield of wheat have been studied extensively to address the threats posed by climate change on food security, the combined effects of these factors have been studied to a lesser extent. This study thus aims to investigate the interactive effects of different regimes of fertilizer and soil moisture on the yield and amino acid composition of wheat. Twelve treatments under different regimens of soil moisture and fertilizer, replicated ten times in a randomized block design were considered in the greenhouse and in the field. The study reveals that variation in each factor had a significant effect on wheat but soil moisture was the principal factor controlling yield and protein accumulation. Application of organic fertilizer to wheat increased amino acid accumulation when the average temperature was at 18oC, with minimum temperature (Tmin) and maximum temperature (Tmax) of -6oC and 42oC respectively. However, application of inorganic fertilizer to wheat enhanced amino acid accumulation when the average daily temperature was at 8oC, with Tmin and Tmax of -10oC and 26oC respectively. Our results also show that a decrease in soil moisture from 100% to 30% in the greenhouse improved the quantity of amino acid in the grain by 26.4% and 56.8% for organic and inorganic treatments respectively. Also, grain amino acid concentration increased by 16.6% and 4.76% when soil moisture dropped from 100% to 30% for the organic and inorganic treatments in the field respectively.
... The high average performance shown by accessions Q12, Q18, Q26 and Regalona-Baer might be explained by the relatively high harvest index (Figs 3, 4) and high 1000-seed 30 weight, seed perimeter and seed area (Supplementary Materials table S1, available at the journal's website). These four highyielding accessions had low average protein, although this relationship is not surprising; it is known that yield is inversely proportional to quality, and that an increase in 35 protein content is made at the expense of yield (Pleijel et al. 1999). ...
Article
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Agronomic and seed quality traits in quinoa accessions grouped according to seed colour (i.e., ochre and yellow) were investigated and compared with the white commercial cultivar ‘Regalona-Baer’. These accessions were previously selected from a range of accessions of diverse origin and seed colour, for their potential value in a breeding programme for cultivars adapted to the southern Italian environment. Field trials were conducted in Foggia, southern Italy, in 2009 and 2010. The aim was to further identify elite genotypes that are suited to the Mediterranean basin in terms of high yields of quality seed, using principal component analysis and hierarchical cluster analysis. The Genotype and Year effects were statistically significant for most of the parameters investigated, while the Genotype × Year interaction was only significant for seed quality. There were significant differences between the two seed colour groups for most of the investigated traits, but not for total dry weight, days to flowering, and soluble and insoluble fibre. The major difference between the accessions and ‘Regalona-Baer’ was lower seed yield for the ochre seed group (30% lower, on average); this was associated with increased plant height (13% higher, on average), more days to maturity (6 days more, on average) and shorter panicle length (21% shorter, on average). These results were observed for both growing seasons. The seed yield of the yellow seed group was similar to ‘Regalona-Baer’. Focusing on individual accessions, principal component analysis indicated that accessions Q12, Q18 and Q26 performed like ‘Regalona-Baer’ for seed yield, 1000-seed weight, seed area, and seed perimeter, while accession Q4 had the highest protein and kaempferol contents for both years. Seed area and perimeter, harvest index, and 1000-seed weight showed positive associations with seed yield, while days to flowering, days to maturity, and quality traits were negatively correlated with seed yield for both years. Cluster analysis carried out on all of the agronomic and seed quality traits did not show clear clustering of the accessions based only on seed colour. The results of this study confirm that both the ochre and yellow quinoa seed groups included elite accessions that can be used directly in future selection programmes for the development of high-yielding varieties that are well adapted to the Mediterranean environment.
... Rice grain is a major plant source of energy and protein for humans and animals worldwide (Zhao et al. 2014). However, grain quality (e.g. grain protein) may be negatively associated with grain yield in crops (Pleijel et al. 1999;Rharrabti et al. 2001;Triboi et al. 2006). To further explore the possible roles of OsDCL3b in grain quality and reveal the relationship between grain quality and grain yield, nutrient components of head rice including protein, amino acids and fat contents were analyzed. ...
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Key message We reported that knockdown of OsDCL3b decreased grain yield but increased grain quality in rice, which is helpful for molecular breeding in crops. Abstract Multiple DICER-LIKE (DCL) genes usually exist and show diverse biochemical and phenotypic functions in land plants. In rice, the biochemical function of OsDCL3b is known to process 24-nucleotide panicle phased small RNAs, however, its phenotypic functions are unclear. Here we reported that knockdown of OsDCL3b led to reduced pollen fertility, seed setting rate, and decreased grain yield but increased grain quality in rice. To reveal the molecular mechanism of the above phenomena, extracted RNAs from rice panicles of the wild type (WT) and OsDCL3b-RNAi line S6-1 were analyzed by deep sequencing. It showed that knockdown of OsDCL3b affected the biogenesis of both 21- and 24-nucleotide small RNAs including miRNAs and phased small RNAs. Using RNA-seq, 644 up- and 530 down-regulated mRNA genes were identified in panicles of line S6-1, and 550 and 273 differentially spliced genes with various alternative splicing (AS) events were observed in panicles of line S6-1 and WT, respectively, suggesting that OsDCL3b involved in influencing the transcript levels of mRNA genes and the AS events in rice panicles. Thus, our results show that knockdown of OsDCL3b will affect the biogenesis of small RNAs, which is involved in regulating the transcription of mRNA genes, and consequently influence the grain yield and quality in rice.
... The studies on a limited number of crops have been accomplished to investigate any changes in crop quality under ozone exposure. For example, the productivity of wheat was declined under ozone exposure, but the concentration of grain protein was raised (Pleijel et al., 1999). In addition, ozone had also a positive impact on the quality of potato tubers by decreasing sugars and enhancing the vitamin C concentration (Piikki et al., 2003). ...
... -0.193 and -0.183). The negative association of grain yield with grain protein content which presents a major obstacle in their simultaneous improvement had also been earlier reported by different workers (Austin et al. 1980, Pleijel et al. 1999, Groos et al. 2003, Barneix 2007, Blanco et al. 2012, Wurschum et al. 2016, Rapp et al. 2018. In this study, most of the high protein lines were low yielding, however, some of the lines with high protein content (progeny no. 12, 17, 84 and 85) were at par to the check variety for grain yield. ...
Article
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Genetic biofortification is a strategy that uses plant breeding techniques to produce staple food crops with higher micronutrient levels and can be a feasible and costeffective means of delivering micronutrients to population that may have limited access to diverse diets. The present study reports the development of wheat with high grain protein, yellow pigment and high zinc content in addition to introgression of rust resistance genes to ensure biofortification as well as yield sustainability. A convergent cross for combining gene(s) for high protein, high yellow pigment, high zinc and rust resistance was performed. This included crossing BC1F2 introgression lines of cross PBW698/BF22//PBW698 carrying grain zinc QTL introgressed from Triticum monococcum with high protein line BWL3560 having Gpc-B1. A set of 192 F3 lines were evaluated for agronomic and quality traits. Molecular marker analysis of F3 progenies for Gpc-B1 gene (Xucw108) revealed 129 F3 lines to be homozygous positive. The progenies showed the range of 8.96-13.92% for grain protein content, 25.1-36.3mg/Kg for grain iron concentration, 34.0-54.0 mg/Kg for grain zinc concentration and 2.01-4.57ppm for grain yellow pigment content compared to 9.65%, 26.7 mg/Kg, 42.9 mg/Kg and 3.74ppm respectively in recipient line PBW698. Therefore, this population constituted a useful material for identifying the nutritionally enhanced lines.
... Proteins account for 10-30 % of the wheat grains dry weight but further increased under water deficit stress (Triboi and Triboi-Blondel, 2002), but grain yield is reduced if water deficiency persists throughout the growing season (Ozturk and Aydin, 2004). Exposure of stress at the grain filling stage favors the deposition of proteins in the grains over carbohydrates translocation (Fernandez-Figares et al., 2000;Pleijel et al., 1999). Water deficit stress affects the amylose and amylopectin ratio and reduces the amount of amylose in the seeds (Singh et al., 2008). ...
Article
In many regions of the world, the incidence and extent of drought spells are predicted to increase which will create considerable pressure on global agricultural yields. Most likely among all the abiotic stresses, drought has the strongest effect on soil biota and plants along with complex environmental effects on other ecological systems. Plants being sessile appears the least resilient where drought creates osmotic stress, limits nutrient mobility due to soil heterogeneity, and reduces nutrient access to plant roots. Drought tolerance is a complex quantitative trait controlled by many genes and is one of the difficult traits to study and characterize. Nevertheless, existing studies on drought have indicated the mechanisms of drought resistance in plants on the morphological, physiological, and molecular basis and strategies have been devised to cope with the drought stress such as mass screening, breeding, marker-assisted selection, exogenous application of hormones or osmoprotectants and or engineering for drought resistance. These strategies have largely ignored the role of the rhizosphere in the plant's drought response. Studies have shown that soil microbes have a substantial role in modulation of plant response towards biotic and abiotic stress including drought. This response is complex and involves alteration in host root system architecture through hormones, osmoregulation, signaling through reactive oxygen species (ROS), induction of systemic tolerance (IST), production of large chain extracellular polysaccharides (EPS), and transcriptional regulation of host stress response genes. This review focuses on the integrated rhizosphere management strategy for drought stress mitigation in plants with a special focus on rhizosphere management. This combinatorial approach may include rhizosphere engineering by addition of drought-tolerant bacteria, nanoparticles, liquid nano clay (LNC), nutrients, organic matter, along with plant-modification with next-generation genome editing tool (e.g., CRISPR/Cas9) for quickly addressing emerging challenges in agriculture. Furthermore, large volumes of rainwater and wastewater generated daily can be smartly recycled and reused for agriculture. Farmers and other stakeholders will get a proper knowledge-exchange and an ideal road map to utilize available technologies effectively and to translate the measures into successful plant-water stress management. The proposed approach is cost-effective, eco-friendly, user-friendly, and will impart long-lasting benefits on agriculture and ecosystem and reduce vulnerability to climate change.
... Although a favorable impact of CO 2 enrichment on the growth and yield of C 3 cereal crops is observed, reductions in flour quality due to declined N content are likely in a CO 2 -enriched environment (Fangmeier et al., 1999), thereby counteracting the effect of O 3 on flour quality (Vandermeiren et al., 1992;Pleijel et al., 1999). Rudorff et al. (1996) indicated that the maximum benefits for wheat production in response to elevated CO 2 will not be accomplished under a simultaneous increase in O 3 concentration. ...
Chapter
The industrial revolution, population explosion, urbanization, and the use of advanced technological instruments have accelerated the consumption of fossil fuels leading to changes in the gaseous composition of the Earth’s atmosphere. The combustion of fossil fuel acts as a principal source of carbon dioxide (CO2) and is still contributing to its continuous rise in the atmosphere. The levels of CO2 in the atmosphere have significantly increased since the preindustrial era and future projections predict that its concentration will be doubled in the next 50 years, which will cause a significant impact on global weather patterns, including temperature increases by an average of 0.5°C per decade. As per future projections regarding greenhouse gases made by the Intergovernmental Panel on Climate Change, the projected levels of CO2 will range from 500 to 1000 ppm by the end of the 21st century. Currently, crop plants are exposed to CO2 levels that have not been experienced from the time of the preindustrial era, and agriculture is facing a future of uncertain consequences of global climate change. An understanding of the influence of climate change on future crop production requires an appreciation of the general responses of a range of crop types to elevated CO2 contents and the ways in which those affects interact with other factors. Rising CO2 is considered an important aspect of global climate change as it has the potential to enhance crop productivity, which will be required to feed the increasing population across the globe. The objective of this chapter is to present an overview of the responses of plants to high CO2 and the fundamental mechanisms behind those responses.
... This finding indicated that higher nitrogen concentration in grain is attributable to lower nitrogen use efficiency of faba bean. Pleijel et al. [46] explained that the primary cause for inverse relation between grain yield and grain nitrogen content is the dilution of protein by non-nitrogen compounds. In support of this conclusion, Cox et al. [47] earlier stated that increase in grain yield due to increased carbohydrate deposition through photosynthesis has a dilution effect on grain nitrogen concentration. ...
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This study reports the effectiveness of some selected rhizobium strains in enhancing nitrogen fixation and nutrient uptake in Vicia faba L. Multi-location field experiments were conducted for two years (2016 and 2017) using a split-plot in randomized complete block design. Treatments comprised six rhizobium strains as the main plot factor and three varieties of Vicia faba as the sub-plot factor. Non-inoculated plants with or without N fertilizer served as +N and −N controls, respectively. Peat carrier-based inoculant of each strain was applied at the rate of 10 g kg-1 seed. Data on nodulation were taken at the late-flowering stage, whereas nitrogen and phosphorus concentrations in plant parts were analyzed at physiological maturity. The total nitrogen difference method was employed to quantify nitrogen fixation. Location x rhizobium strain x variety interaction had a significant effect on nodule dry weight plant-1. Rhizobium strains significantly enhanced nodulation, nitrogen fixation, nutrient uptake and soil nitrogen balance. Inoculation with NSFBR-12 and NSFBR-15 resulted in the highest nitrogen fixed, nutrient uptake and soil nitrogen balance. Vicia faba inoculated with the two top performing strains, NSFBR-12 and NSFBR-15 fixed respectively 87.7% and 85.5% of the total nitrogen uptake. Non-inoculated plants fulfilled proportionately more of the total nitrogen uptake through nitrogen derived from the soil rather than fixed nitrogen. Soil available phosphorus and pH had appreciable influences on nitrogen and phosphorus uptake of inoculated Vicia faba. Inoculation with competitive and effective rhizobium strains can improve soil nitrogen balance, nitrogen fixation and nutrient uptake of Vicia faba.
... In addition, elevated O 3 was reported as a factor leading to rice (Oryza sativa) yield loss of approximately 15-20% (Shi et al. 2009). Pleijel et al. (1999) reported that excess H 2 O 2 levels after O 3 exposure caused visible foliar symptoms and yield loss in crop plants. Total global rice consumption increased continuously at an annual rate of + 1.4% from 2008 to 2018 (FAOSTAT 2019;Grain Central 2018). ...
Article
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Increasing ozone concentration is one of the oxidative stresses that affects rice yield loss in many countries. Catechin and salicylic acid were proposed as tools for alleviating oxidative stress in plants, but their roles in protecting rice productivity under ozone stress still remained unknown. We investigated the mechanism of catechin and salicylic acid on rice under ozone stress at the vegetative stage and at the reproductive stage. Rice was sprayed with catechin and salicylic acid before exposure to ozone in the range of 100–150 ppb (8 h day−1). Ozone and salicylic acid led to a decrease in chlorophyll contents, magnesium contents, and stomatal conductance. This evidence led to a decrease in rice productivity and quality. In contrast, under rice + catechin, both ambient air and elevated ozone conditions had to higher rice productivity and quality than under rice alone and rice + salicylic acid conditions. Catechin could mitigate ozone stress in rice plants through maintaining chlorophyll contents, magnesium contents, and stomatal conductance. Moreover, catechin could induce an unregulation of ascorbate peroxidase, and catalase genes led to increasing their antioxidant enzyme activity. Increasing of antioxidant enzyme activity under rice + ozone + catechin conditions attributed to lower lipid peroxidation than under rice + ozone especially at vegetative stage. This study confirmed that catechin, which is naturally found in tea leaves, could be used as an ozone protectant. The protective role of catechin on chlorophyll contents and antioxidant systems at the vegetative stage attributed to maintaining rice yield under ozone stress. Graphical abstract
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Air pollutant concentrations such as ozone (O3) and peroxides have been increasing in the world, and may cause many negative impacts on crop production. The objectives of the present study are to investigate the effects of peroxides and O3 on visible foliar injury and physiological responses, and to compare the sensitivities among two Thai rice cultivars, RD 31 and Chainat 1, and two Japanese rice cultivars, Nipponbare and Nourin 52, under exposure to single O3 and combined O3 and peroxides. Four treatment plots were prepared, namely control plot (O3 2-3 ppbv and free peroxides), O3 50 ppbv plot and free peroxides, O3 50 ppbv and peroxides 3 ppbv plot and O3 50 ppbv and peroxides 5 ppbv plot. The results showed that combined O3 and several ppbv peroxides plots caused severe damage on visible leaf injury, increase in Malondialdehyde (MDA) concentration, and decrease in total chlorophyll content and a net photosynthetic rate much higher than single O3 plot. According to the O3 dose response analysis, we found that, in combined O3 (50 ppbv) and peroxides (3 ppbv and 5 ppbv) exposure, in case of visible foliar injury, Chainat 1 was seriously damaged rice cultivar while Nipponbare was a less damaged rice cultivar.
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A study was conducted during April 2007 to May 2009 to examine the ozone status, its effects on crops and to mitigate ozone losses in Bangladesh Agricultural University Campus, Mymensingh. Ozone concentrations were measured at 4 weeks interval using passive samplers.
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In order to Evaluation of different fertility systems and cultivars on wheat In Khuzestan conditions, a filed experiment was conducted Experimental field of Ramin Agriculture and Natural Resources University in Ahwaz, south-western of Iran, during 2008- 2009 growing season. Treatments were arranged as a split-plot experiment in a randomized complete block design with three replications. Fertilizer treatments at four system (inorganic1, inorganic2, chicken manure and chicken manure + biofetilizers) and six cultivars (Veenak, Chamran, Star, D-79-15, Karkheh and SP-50) were main plots and sub plot respectively. The result indicated that application organic manure and biofertilizer the grain yield, biological yield, harvest index, 1000-grain weight and chlorophyll content was increased, but at control, kernels per spike and grain protein content had the highest amount. The superiority of organic manure may be attributed to balanced and gradual release of plant nutrients and increased water holding capacity to support growth. The highest grain yield were in all fertility systems, in late maturing bread (star) and durum (SP50) wheat cultivars were long growth season and extensive root system. Generally, wheat yield and its component were increased, by application of animal manure and biofertilizer, as well as from application of inorganic nutrients.
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Wild barley (Hordeum spontaneum), the progenitor of cultivated barley, is an important genetic resource for cereal improvement. Iron (Fe) and zinc (Zn) are essential minerals for human good health. In the current study, the grain Fe and Zn concentrations (GFeC and GZnC) of 92 H. spontaneum genotypes collected from nine populations in Israel, and ten barley cultivars (Hordeum vulgare) from five provinces in China were investigated. Remarkable variations in GFeC and GZnC were found between and within wild barley populations, ranging from 10.8 to 329.1 and 66.3 to 493.9 mg kg−1 among the 92 wild genotypes with an average of 74.3 and 173.9 mg kg−1, respectively. The mean value of GFeC and GZnC in each population varied from 48 to 146 and 96 to 291 mg kg−1, respectively. Significant correlations were found among four ecogeographical factors out of the 14 studied, including both GFeC and GZnC. Wild barley exhibited higher values and greater diversity of GFeC and GZnC than its cultivated counterparts. The higher Fe and Zn grain concentrations found in H. spontaneum suggest that wild barley germplasm confers higher abilities for mineral uptake and accumulation, which can be used for genetic studies of barley nutritional value and for further improvement of domesticated cereals.
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Northern, Southern and Equatorial Africa have been identified as among the regions most at risk from very high ozone concentrations. Whereas we know that many crop cultivars from Europe, north America and Asia are sensitive to ozone, almost nothing is known about the sensitivity of staple food crops in Africa to the pollutant. In this study cultivars of the African staple food crops, Triticum aestivum (wheat), Eleusine coracana (finger millet), Pennisetum glaucum (pearl millet) and Phaseolus vulgaris (bean) were exposed to an episodic ozone regime in solardomes in order to assess whether African crops are sensitive to ozone pollution. Extensive visible leaf injury due to ozone was shown for many cultivars, indicating high sensitivity to ozone. Reductions in total yield and 1,000‐grain weight were found for T. aestivum and P. vulgaris, whereas there was no effect on yield for E. coracana and P. glaucum. There were differences in sensitivity to ozone for different cultivars of an individual crop, indicating that there could be possibilities for either cultivar selection or selective crop breeding to reduce sensitivity of these crops to ozone.
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The area of wheat cropping in La Pampa province is included in the Region V South of Argentina for production of that cereal, where water and nitrogen low availabilities are the main limiting factors for wheat grain yield. The present work was aimed at analyzing grain yield and changes in grain protein composition of four genotypes of Triticum aestivum L. subjected to different availability levels of water and nitrogen. The assay was performed in pots under greenhouse condition and utilizing wheat cultivars ACA 315, Baguette Premium 11, Klein Proteo and DM Cronox. At the start of flowering half of the pots were fertilized with 100 kg N ha-1 and, until grain harvest, half of the pots were kept at 50 and the other half at 100% field capacity. Grain yield components, greenness index, grain protein concentration, grain nitrogen content and gliadins and glutenins concentration in flour were the variables determined in the assay. DM Cronox was the cultivar that expressed the highest grain yield. Under conditions of limiting water availability, the gluteninrich fraction increased and that of gliadins decreased in two of the genotypes, whereas addition of nitrogen led to an increase only in the glutenin content. Concentrations of protein fractions are associated to grain nitrogen content, mainly for gliadins. The change in wheat grain protein fractions upon variation of water and nitrogen availabilities depends on the genotype environment relationship. DOI: http://dx.doi.org/10.19137/semiarida.2017(02).3750
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Tropospheric O3 is considered as the most widespread secondary pollutant and one of the components of global climate change. Agriculture plays a very important role in human welfare. O3 has been recognized as a prime threat to agricultural production. The projected levels to which O3 will increase are critically alarming and have become a major cause of concern for global food production. Impact of tropospheric O3 on wheat production has been widely studied. Wheat is identified as sensitive to O3. It enters into the plant through the stomata, affecting directly cell membranes, generating O3-induced ROS, and up- or downregulating ROS signaling molecule-associated genes, genes, proteins, and metabolites which ultimately affects growth and yield of wheat. The objectives of the chapter are to present an overview picture on the effect of O3 on wheat productivity and to summarize the vast number of available reports on the impact of O3 on wheat physiology and morphology, its defense and variation in allocation pattern of photosynthates, and its yield and quality.
Chapter
The concentrations of atmospheric compounds such as greenhouse gases, heavy metals and trace gas air pollutants have rapidly changed. Many of these compounds interact with agricultural systems and influence crop performance, both directly by affecting growth and quality or indirectly by altering the plant’s ability to cope with other abiotic and biotic stresses. Some atmospheric compounds have little or no discernible impact on the environment; others reach levels that exceed thresholds for damage to crops. In this review, we analyse the literature on airborne species that directly impact crop growth and health. In Europe and North America emissions of SO2, NOx and heavy metals have declined during the past decades and are currently not considered as a major threat to crops. By contrast, air pollutant emissions have been increasing in rapidly growing regions of Asia, Africa and Latin America. Ozone is the most phytotoxic of the common air pollutants. The widespread distribution of O3 already presents a risk to crop growth and health in many regions of the world. It is concluded that the continuous increase in background O3 concentrations will pose a critical threat to future world food security. Interactions with both biotic and abiotic factors must be taken into account in assessing risks of air pollutants in the field. There is evidence that these indirect effects could be more important under certain circumstances than the direct effects of air pollutants on plants. The parallel rapid increase in atmospheric CO2 concentrations accompanied by climate change has two major implications: (1) a possible benefit to crop growth by direct stimulation of photosynthesis and by mitigation of gaseous air pollutants and water stress; and (2) a threat to crop production due to an enhancement of crop quality losses.
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Humans have been exploiting the natural resources from the dawn of civilization, but the exploitation has accelerated at a very high rate since the Industrial Revolution. Atmosphere, hydrosphere, and lithosphere are utilized as resource as well as medium for discharge of waste products, which results in physicochemical changes in the quality of air, water, and soil that have harmful biological consequences. The chemical composition of the atmosphere is being modified by the injection of gases, particulates, and volatile substances that may upset the normal functioning of environment at varying degrees and run the risk of inducing irreversible ecological changes.
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BACKGROUND Tropospheric ozone (O3) being phytotoxic impacts global food security. Present study investigated yield responses and kernel quality traits of two maize cultivars [DHM117: normal maize (NM)] and [HQPM1: quality protein maize (QPM)]. Cultivars were exposed to two doses of elevated O3 viz. NFC+15 and NFC+30 ppb O3 above ambient level (NFC, non‐filtered chambers) while filtered chambers served as control. RESULTS Test weight (thousand kernel weight), weight of kernels m‐2 and kernel starch content reduced more in NM than QPM due to elevated O3 exposure. Total soluble and reducing sugars increased in both the cultivars being more in NM. Though, endosperm protein showed comparatively more increase in QPM than NM, decline in essential amino acids tryptophan and lysine was higher in QPM. Majority of nutrient elements increased after O3 treatment, while reductions in oil content as well as saturated fatty acids were observed in both test cultivars. Of the two essential fatty acids, omega 3 fatty acid reduced while omega 6 fatty acid contents increased in QPM. Oil became more unsaturated (increase in polyunsaturated fatty acids) upon O3 exposure, thus increasing its reactivity and hence became more prone to auto‐oxidation. CONCLUSION Elevated O3 caused losses in yield of maize cultivars and NM showed higher sensitivity than QPM. Kernel quality analysis revealed significant changes in nutritional parameters. Carbohydrate content reduced more in NM, while essential amino acids and saturated fatty acids showed more decline in QPM. This article is protected by copyright. All rights reserved.
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Climate holds a key position in driving the agriculture of an area. The changing climatic conditions are becoming a big threat for safety of agricultural system and food security across the globe. In developing countries of Asia and Africa, declining soil fertility and drought are the major constraints in harvesting the potential yields. The average temperature around the globe is also expected to rise globally by 6°C in the coming century which is mainly due to uncontrolled emission of greenhouse gases. A prominent elevation in CO 2 and CH 4 concentration has been observed in the past centuries largely due to fossil burning and urbanization. Further upto 35 percent increase in the concentration of nitrous oxide is also expected due to injudicious use of nitrogenous fertilizers. According to the prediction of climate models the rise in temperature and frequent happening of severe drought are going to affect the agricultural productivity in 21 st century. In order to sustain the agricultural productivity it is need of the hour to properly understand the impact of these changes on soil fertility and crop productivity. This review is aimed to highlight the potential impacts of rising temperature, shifting precipitation patterns and rising CO 2 concentrations on soil health and agricultural productivity. Soil organic carbon pool is also going to get negatively affected by these changing climatic conditions. It has also been tried to shed some light on the potential of various carbon sequestration strategies conservation tillage, cover crops, Proper nutrient management, proper irrigation management and restoration of degraded soils, in combating the devastating impacts of changing climate. In addition the nitrogen management strategies are also elaborated alongwith manure management to minimize the emission of greenhouse gases.
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This review presents tropospheric ozone (O 3), an air pollutant affecting agriculture by reducing crop yield and deteriorating quality of produce. O 3 enters leaves through stomata and diffuses within the apoplast, producing many oxidizing compounds and affecting various physiological and biochemical processes, crop growth and yield. O 3 affects above and below ground carbon allocation and its dynamics, N cycling, microbial content and emission of greenhouse gases (GHG) from soil. This review focuses on the impact of O 3 on crop growth with special emphasis on productivity in Asian region, methods for evaluating O 3 responses in field, amelioration of O 3 induced injury and providing dose-response functions for economic assessments.
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Artificial manipulation of sink and source was carried out in several bread wheat varieties in order to study the variations in the pattern of storage products accumulation in the grain. In a first experiment, partial ablation of the laminae did not cause any significant variation in the yield components, while total elimination of the laminae resulted in a decreased fertility of the spikelets and in a lower kernel weight. The protein content of grain turned out to be a function of the amount of vegetative organs left in the different treatments, and ranged from 11.1 % in leafless plants to 16.5% in the control. The halving of the spikes led to a 14% increase in the size of the kernels, while the protein content per spike showed a 20 % drop in comparison to the control. Reduction of sink affected nitrogen accumulation to a lesser extent than carbohydrates storage in the grain. Reduction of sink induced remarkable increases in the protein fractions: gliadins +59%, glutelins +44%, insoluble residue +30%, non-proteic nitrogen +28%, albumins and globulins + 16%. The increase of GPC or of specific solubility classes did not influence significantly the quality of the flour evaluated by the Zeleny and Pelshenke indices. The presented data suggest some caution in adopting kernel size and GPC as main selection criteria in early generations. It seems more convenient to select for a prolonged grain filling period and for a higher biomass without increasing plant height.
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The flux of O3 was determined in open-top chambers (OTC) used to investigate its effect on spring wheat (Triticum aestivum L., cv. Albis) in 1989 and 1990. The experimental site was located at 900 m above sea level at Zimmerwald, near Bern (Switzerland). The aims were to evaluate the use of OTCs for O3 flux measurements under field conditions, to assess the role of stomata in controlling the O3 fluxes, and to establish a quantitative relationship between radiation-weighted O3 concentrations and O3 flux. Measurements were carried out from full expansion of flag leaves until the onset of senescence. Ozone flux was determined by mass balance using the concentrations of O3 measured at the inlet and outlet of the OTC. The CO2 exchange rate was corrected for soil-borne COO and used as a reference. Measurements of temperature, photosynthetically active radiation (PAR), saturated water vapour pressure deficit (SVPD), and boundary layer conductance were used to describe the microclimate inside OTCs.
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summarySpring wheat, Triticum aestivum L., cv. Drabant, was exposed to different concentrations of ozone in open-top chambers for one growing season, at a site located in south-west Sweden. The chambers were placed in a field of commercially grown spring wheat. The treatments were charcoal-filtered air (CF), non-filtered air (NF), non-filtered air + 25 nl 1−1ozone (NF +) and non-filtered air + 35 nl 1−1ozone (NF++). Ozone was added daily between 11.00 and 18.00 h, starting at anthesis. Fumigation with elevated concentrations of ozone caused chlorosis of the flag leaves. In the NF++ and NF+ treatments chlorosis appeared after 7 and 20 days of fumigation, respectively, and in the CF treatment after about 34 days, A progressive series of changes occurred in the mesophyll cells of the flag leaves after ozone fumigation. Starting at anthesis, the first changes occurred in the cytoplasm and involved a decrease in the amount of cytoplasm and an increase in the vacuolization of the cells. Subsequently the chloroplasts became affected decreasing in area and containing more plasto-globuli. Finally vesicles were formed between the grana thylakoids and at the same time the plasma membrane came loose from the cell wall and convoluted. The mitochondria remained unaffected until only lipid droplets, oleosomes, were left in the cells. These changes were not specific for ozone as they occurred also in the CF treatment, although later in time. This indicates that ozone causes premature senescence in wheat flag leaves.
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Eight Nordic open‐top chamber experiments with field‐grown spring wheat were combined to obtain relationships between ozone exposure and yield loss. Two exposure indices, AOT30 and AOT40 (AOT = accumulated exposure over threshold), were tested. Strongly significant linear regressions between relative yield and exposure were obtained with both indices. The coefficient of determination (r) was higher and the model assumptions of linear regression were satisfied to a larger extent with AOT30 than with AOT40. The exclusion of charcoal‐filtered treatments from the analysis made little difference to the regressions. The AOT30 regression model predicted larger yield loss than the AOT40 regression model, especially for the range of exposures, which is likely to occur in the Nordic countries. The protein content of the grain increased with increasing ozone exposure in all eight experiments, but to a varying degree.
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Cereal Chem. 73(6):762-766 Elevated levels of atmospheric CO2 have been shown to increase grain produced poorer dough and decreased loaf volume, farinograph devel- yield and reduce grain nitrogen concentration. The object of this study opment time, and dough extensibility. These changes were largely attrib- was to determine whether elevated CO2 levels would modify other utable to the lower protein content of the grain grown at elevated CO2. aspects of grain quality relevant to processing, particularly protein and There did not appear to be major changes in protein composition or in the starch quality. Wheat of two genotypes (Hartog and Late Hartog) was functional properties of the protein. Grain produced at elevated CO2 grown in the field in controlled-atmosphere tunnels at either the ambient yielded starch with a significantly higher proportion of large (A-type) level of CO2 (350 pl/L) or an elevated level (700 jud/L). This elevated starch granules but no overall change in amylose-to-amylopectin ratio. level of CO2 produced significant increases in grain yield, but decreases These studies indicate that elevated levels of CO2 may result in decreased in 1,000-kernel weight. Grain grown in the elevated CO2 atmosphere quality of bread wheats largely due to lowered protein content.
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The probable effect of the increasing global atmospheric CO/sub 2/ concentration on agricultural yields was evaluated. More than 430 observations of the yields of 37 species grown with CO/sub 2/ enrichment were extracted from more than 70 reports published during the past 64 years. These observations are tabulated in the Appendices. The ratios of the yield of CO/sub 2/-enriched plants to their respective controls were computed and statistically analyzed. CO/sub 2/ enrichment increased the economic yield of all mature agricultural crops by 28% with a 99.9% confidence interval from 22 to 35%. Excluding flower crops whose yield was measured by number of blooms, the mean yield increase with CO/sub 2/ enrichment was 36%. An additional 79 observations were also analyzed from experiments that were terminated before the plants matured and whose yield was indicated by total plant weight or height. Pooling these immature plant data with the mature plant results gave a mean yield increase of 33%. Further analysis of 81 experiments which had controlled CO/sub 2/ concentrations for their duration showed that yields probably will increase by 33% (with a 99.9% confidence interval from 24 to 43%) with a doubling of atmospheric CO/sub 2/ concentration.
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In a study designed to investigate the nature and basis of the relationships between grain yield (GY) and grain protein concentration (GBC) in common wheat, 11 populations, including 4 homozygous-homogeneous and 7 heterozygous-heterogeneous populations, were evaluated in a space planted and a solid seeded trial. Analysis of yield and protein data from each population revealed that phenotypic and environmental correlations between GY and GPC were negative and highly significant, whereas genetic correlation was significant in only one of 7 segregating populations studied. These results suggested that the inverse relationships between GY and GPC, although phenotypically real, were not caused by genetic factors. It would appear that environmental factors, source-sink interactions, and dilution of protein by non-protein compounds were the major agents that caused undesirable associations between the two traits.
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Two cultivars each of spring wheat (Triticum aestivum L., cv. Star and cv. Turbo) and spring barley (Hordeum vulgare L., cv. Alexis and cv. Arena) were exposed season-long to ambient (384 p.p.m.) and above ambient CO2 concentrations (551, 718 p.p.m.) in open-top chambers. Plant samples were taken at the booting stage and at maturity. Concentrations (grams per gram dry weight) of macro (Ca, K, Mg, N, P, S) and micronutrients (Fe, Mn, Zn) were measured in stems, leaves, ears and grains, and the amino acid composition of the grain protein was determined.For most nutrients studied the sequence and size of the response of the four cereal plants to the CO2 enrichment was cv. Arena < cv. Alexis < cv. Turbo < cv. Star. The CO2 enrichment usually produced a decrease in nutrient concentrations, which was already detectable at the booting stage and was further enhanced until plant maturity. Nutrient concentrations of straw were more affected than those of grains. The decrease in concentration was greatest for N followed by Mg, Ca and K, and the maximum decrease as compared with ambient CO2 amounted to 43%, 35%, 33% and 21% for straw, and 30%, 13%, 28% and −6% for grains. Concentrations of micronutrients were also found to be partially decreased by about 10–30%. At 718 p.p.m. CO2 grain protein concentrations were 96% (cv. Arena), 85% (cv. Alexis), 72% (cv. Turbo) and 70% (cv. Star) of the ambient CO2 value, however, the index of essential amino acids was increased. Overall, the CO2 enrichment did not decrease the nutrient harvest index of all nutrients except of sulphur. Nutrient use efficiency increased by high CO2 levels for cv. Star and cv. Turbo and decreased for cv. Arena.
Article
Spring wheat (Triticum aestivum L., cv. Albis) was grown in the field at a site located in central Switzerland, and exposed to chronic doses of ozone (O(3)) in open-top chambers to study impacts on yield. The experiment was carried out in 1986, 1987 and 1988. The treatments used included charcoal-filtered air (CF), non-filtered air (NF) and non-filtered air to which constant amounts of O(3) (two levels, O(3)-1 and O(3)-2) were added daily from 09.00 until 17.00 local time. Mean solar radiation-weighted O(3) concentrations during the fumigation period were in the range 0.016-0.022 microl litre(-1) (CF), 0.036-0.039 microl litre(-1) (NF), 0.057-0.058 microl litre(-1) (O(3)-1, used in 1987 and 1988 only) and 0.078-0.090 microl litre(-1) (O(3)-2). Fumigation was maintained from the three-leaf stage until harvest. Ambient plots were used as a reference. Plant characteristics examined included straw yield, grain yield, number of grains per head, number of heads per surface area, weight of individual grains and harvest index (ratio of grain weight to total dry weight). Pollutant concentrations and other environmental parameters were monitored continuously inside and outside the chambers. In 1986 and 1987, enclosure mostly increased the values of different parameters, while in 1988, they were decreased. The negative enclosure effect was due to extremely turbulent winds, which caused lodging inside the chambers. In all 3 years, increasing O(3) concentrations negatively affected the parameters studied, except for the number of heads per surface area, which showed no treatment response. Grain yield showed a very sensitive response to O(3). The effect of O(3) on grain yield was due to an effect primarily on grain size and secondarily on grain number. The relative response of grain yield to O(3) was similar in all 3 years, despite year-to-year differences in climatic conditions and enclosure effects. The analysis of the data for combined years revealed an increase of about 10% in grain yield due to air filtration. The corresponding increase in straw yield was only about 3.5%. Exposure-response models were developed for individual years and combined years. It is concluded that, in the study area, ambient O(3) may affect grain yield in spring wheat.
Article
In a three-year study carried out at a rural site in Switzerland, spring wheat (Triticum aestivum L. cv. Albis) was exposed to different levels of ozone (O(3)) in open-top-field chambers from the two-leaf stage until harvest. Field plots in ambient air (AA) were used for comparison. Grain recovered from the different treatments was analyzed for minerals (Ca, Mg, K, P), starch, protein, amino acids and alpha-tocopherol, in order to investigate the effect of O(3) on grain composition. Chamber-enclosure had small effects on some parameters (K, protein), but not on others (starch), as shown by the comparison of data from the AA and non-filtered-air treatment (NF). Differences between NF and charcoal-filtered air (CF) were very small. At O(3) concentrations higher than in the NF treatment (O(3)-1 = 1.5xNF and O(3)-2 = 2.5xNF), mineral contents were higher than in the NF and CF treatments. Protein content was increased only in the O(3)-2 treatment. Starch contents decreased from about 63% in the CF treatment to 54% in the O(3)-2 tratment. No effect of O(3) on the content of alpha-tocopherol and on the essential amino acid index of the protein was observed. It is concluded that compositional changes in wheat grain in response to O(3) are minor, and that ambient O(3) is not likely to cause important changes.
Article
Spring wheat (Triticum aestivum L., cv. Drabant) was exposed to different concentrations of ozone in open-top chambers for two growing seasons, 1987 and 1988, at a site located in south-west Sweden. The chambers were placed in a field of commercially grown spring wheat. The treatments were charcoal-filtered air (CF), non-filtered air (NF) and non-filtered air plus extra ozone (NF(+)). In 1988, one additional ozone concentration (NF(++)) was used. Grain yield was affected by the ozone concentration of the air. Air filtration resulted in an increase in grain yield of about 7% in both years, compared to NF. The addition of ozone (NF(+), NF(++)) reduced grain yield and increased the content of crude protein of the grain in both years. Filtration of the air had no significant effect on the content of crude protein, compared to NF. The results showed a strong positive chamber effect on grain yield in the cold and wet summer of 1987. In 1988, there was no net chamber effect on grain yield. The relative differences between the CF, NF and NF(+) treatments with respect to grain yield were of the same magnitude in the two years, despite the very different weather conditions.
Article
Growth and yield were reduced but (14)C translocation velocity was not affected by increasing levels of ozone in spring wheat exposed in open top chambers to the following treatments: charcoal filtered air (CF), non-filtered ambient air (NF), or NF with addition of 30 microl litre(-1) ozone, 8 h daily (NFO). Destructive harvests were performed at anthesis and at maturity. Parts of the flag leaf or the second leaf were exposed to (14)CO(2) in small cuvettes for 5 min before, during and after anthesis. The translocation velocity was followed by autoradiography and scintillation counting of the plants frozen and lyophilized at different times after labelling. The label was transported at the same velocity in all the treatments. Ozone induced changes in carbon allocation or partitioning should probably be explained as amounts of carbon transported (mg s(-1)), rather than as transportation velocity (mm s(-1)). The amount translocated may be governed by source conditions under O(3) stress: reduced healthy green biomass and photosynthesis, but perhaps also by impairment of phloem loading because of membrane damage.
Growth stage dependence of the grain yield response to ozone in spring wheat Responses of cereals exposed to air pollutants in open-top chambers
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Pleijel, H., Danielsson, H., Gelang, J, Sild, E., Sellde Ân, G., 1998. Growth stage dependence of the grain yield response to ozone in spring wheat (Triticum aestivum L.). Agric. Ecosys. and Environ. 70, 61±68. Ska Èrby, L., Sellde Ân, G., Mortensen, L., Bender, J., Jones, M., De Temmerman, L Wenzel, A., Fuhrer, J., 1993. Responses of cereals exposed to air pollutants in open-top chambers, In: Ja Èger, H.J., Unsworth, M.H., De Temmermann, L., Mathy, P. (Eds.), Effects of Air Pollution on Agricultural Crops in Europe. Results of the European Open-top Chambers Project, Air Pollution Research Report Series of the Environmental Research Programme of the Commission of the European Communities vol. 46, pp. 241±259.
The critical level for ozone to protect agricultural crops ± An assessment of data from European open-top chamber experiments
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Fuhrer, J., 1994. The critical level for ozone to protect agricultural crops ± An assessment of data from European open-top chamber experiments, In: Fuhrer, J., Achermann, B. (Eds.), Critical Levels for Ozone, vol. 16, A UN-ECE Workshop Report, Schriftenreihe der FAC Liebefeld, pp. 42±57.