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Sample records for selected water stress

  1. Gas exchanges and water use efficiency in the selection of tomato genotypes tolerant to water stress.

    Science.gov (United States)

    Borba, M E A; Maciel, G M; Fraga Júnior, E F; Machado Júnior, C S; Marquez, G R; Silva, I G; Almeida, R S

    2017-06-20

    Water stress can affect the yield in tomato crops and, despite this, there are few types of research aiming to select tomato genotypes resistant to the water stress using physiological parameters. This experiment aimed to study the variables that are related to the gas exchanges and the efficiency in water use, in the selection of tomato genotypes tolerant to water stress. It was done in a greenhouse, measuring 7 x 21 m, in a randomized complete block design, with four replications (blocks), being five genotypes in the F 2 BC 1 generation, which were previously obtained from an interspecific cross between Solanum pennellii versus S. lycopersicum and three check treatments, two susceptible [UFU-22 (pre-commercial line) and cultivar Santa Clara] and one resistant (S. pennellii). At the beginning of flowering, the plants were submitted to a water stress condition, through irrigation suspension. After that CO 2 assimilation, internal CO 2 , stomatal conductance, transpiration, leaf temperature, instantaneous water use efficiency, intrinsic efficiency of water use, instantaneous carboxylation efficiency, chlorophyll a and b, and the potential leaf water (Ψf) were observed. Almost all variables that were analyzed, except CO 2 assimilation and instantaneous carboxylation efficiency, demonstrated the superiority of the wild accession, S. pennellii, concerning the susceptible check treatments. The high photosynthetic rate and the low stomatal conductance and transpiration, presented by the UFU22/F 2 BC 1 #2 population, allowed a better water use efficiency. Because of that, these physiological characteristics are promising in the selection of tomato genotypes tolerant to water stress.

  2. Physiological responses of selected African sorghum landraces to progressive water stress and re-watering

    CSIR Research Space (South Africa)

    Devnarain, N

    2016-03-01

    Full Text Available stress treatments and a moderate re-watered treatment on day 7. Plant height, soil moisture, and LWC were measured during harvests. Chlorophyll, carotenoid, and proline contents were quantified. All five genotypes maintained LWC above 80% during mild...

  3. Selection of Almond Vegetative Rootstocks for Water Stress Tolerance Based on the Morphological Markers

    Directory of Open Access Journals (Sweden)

    A.A. Shokouhian

    2016-02-01

    Full Text Available Introduction: One of the microbiological preparations used for this study was Effective Microorganisms (EM, being a commercial mixture of photosynthesizing bacteria, Actinomycetes, lactic acid bacteria, yeasts and fermenting fungi. The microbiological composition of the EM concentrateincludesStreptomyces albus, Propioni bacterium freudenreichil, Streptococcus lactis, Aspergillus oryzae, Mucor hiemalis, Saccharomycescerevisiae and Candida utilis. Moreover, EM also contains an unspecified amount of Lactobacillus sp. Rhodo pseudomonas sp. and Streptomyces griseus. Effective Microorganisms have a positive effect on the decomposition of organic matter, limiting putrefaction, increasing nitrogen content in the root medium of plants, phosphorus, improving soil fertility and as a result contributing to the growth and development of the root systems of plants. Selection of almond vegetative rootstocks for water stress tolerance is important for almond crop production in arid and semi-arid regions. The study of the eco-morphological characteristics that determine the success of a rootstock in a particular environment is a powerful tool for both agricultural management and breeding purposes. The aim of this work was to select the new rootstocks for water shortage tolerance, impact of water stress as well as Effective Microorganism (EM on morphological characteristics of almond rootstocks. Materials and Methods: In order to select the new rootstocks for water shortage tolerance, impact of water stress as well as EMonmorphologicalcharacteristics of almondrootstocks were studiedin thedepartment ofHorticulture, Ferdowsi University of Mashhad, in 2011-2012. The experiment was carried out with four replications in a completely random blockdesign to study the effects of two concentrations of EM (0 and 1%, three irrigation levels (normal irrigation 100%-control-and irrigation after depletion of 33 and 66% of available water, and four almond rootstocks including GF

  4. Selection on crop-derived traits and QTL in sunflower (Helianthus annuus) crop-wild hybrids under water stress.

    Science.gov (United States)

    Owart, Birkin R; Corbi, Jonathan; Burke, John M; Dechaine, Jennifer M

    2014-01-01

    Locally relevant conditions, such as water stress in irrigated agricultural regions, should be considered when assessing the risk of crop allele introgression into wild populations following hybridization. Although research in cultivars has suggested that domestication traits may reduce fecundity under water stress as compared to wild-like phenotypes, this has not been investigated in crop-wild hybrids. In this study, we examine phenotypic selection acting on, as well as the genetic architecture of vegetative, reproductive, and physiological characteristics in an experimental population of sunflower crop-wild hybrids grown under wild-like low water conditions. Crop-derived petiole length and head diameter were favored in low and control water environments. The direction of selection differed between environments for leaf size and leaf pressure potential. Interestingly, the additive effect of the crop-derived allele was in the direction favored by selection for approximately half the QTL detected in the low water environment. Selection favoring crop-derived traits and alleles in the low water environment suggests that a subset of these alleles would be likely to spread into wild populations under water stress. Furthermore, differences in selection between environments support the view that risk assessments should be conducted under multiple locally relevant conditions.

  5. In Vitro Cytotoxicity and Adaptive Stress Responses to Selected Haloacetic Acid and Halobenzoquinone Water Disinfection Byproducts.

    Science.gov (United States)

    Procházka, Erik; Escher, Beate I; Plewa, Michael J; Leusch, Frederic D L

    2015-10-19

    The process of disinfecting drinking water inadvertently leads to the formation of numerous disinfection byproducts (DBPs). Some of these are mutagenic, genotoxic, teratogenic, and cytotoxic, as well as potentially carcinogenic both in vivo and in vitro. We investigated the in vitro biological activity of five DBPs: three monohaloacetic acids (monoHAAs) [chloroacetic acid (CAA), bromoacetic acid (BAA), and iodoacetic acid (IAA)] and two novel halobenzoquinones (HBQs) [2,6-dichloro-p-benzoquinone (DCBQ) and 2,6-dibromo-p-benzoquinone]. We focused particularly on cytotoxicity and induction of two adaptive stress response pathways: the oxidative stress responsive Nrf2/ARE and DNA-damage responsive p53 pathways. All five DBPs were cytotoxic to the Caco-2 cell line after a 4 h exposure, and all DBPs induced both of the adaptive stress response pathways, Nrf2/ARE and p53, in the micromolar range, as measured by two β-lactamase-based reporter gene assays. The decreasing order of potency for all three endpoints for the five DBPs was IAA ∼ BAA > DCBQ ∼ DBBQ > CAA. Induction of oxidative stress was previously proposed to be the molecular initiating event (MIE) for both classes of DBPs. However, comparing the levels of activation of the two pathways uncovered that the Nrf2/ARE pathway was the more sensitive endpoint for HAAs, whereas the p53 pathway was more sensitive in the case of HBQs. Therefore, the DNA damage-responsive p53 pathway may be an important piece of information to fill in a gap in the adverse outcome pathway framework for the assessment of HBQs. Finally, we cautiously compared the potential risk of the two novel HBQs using a benchmarking approach to that of the well-studied CAA, which suggested that their relative risk may be lower than that of BAA and IAA.

  6. Cell suspension culture and mutants selection for resistance to PEG induced water stress in alfalfa (Medicago sativa L.)

    International Nuclear Information System (INIS)

    Zhang Xiaodong; Lin Tingan

    1994-01-01

    Elements affecting suspension cell culture in alfalfa (Medicago sativa L.) were studied and a method of rapid establishment of embryogenic suspension cell lines was introduced. Effects of γ ray irradiation on the growth of suspension cells were studied, and the optimum dose of irradiation for inducing mutants from suspension cells was about 20 ∼ 60 Gy. Effects of PEG and NaCl induced water stress on the growth of suspension cells were also investigated, and the results showed that the congregants of preliminary suspension culture were more susceptible than the established suspension cell lines. With 20 Gy of γ ray irradiation on suspension cell line (JL416), six clones were obtained with 70 days of selection on medium of 15% PEG (about-11 bar). A number of regenerated plants were obtained from these clones. One clone was also gained from medium containing 20% PEG (about-15 bar). The selected mutant cell lines (JP15 and JP20) has strong resistances to high concentration of PEG and NaCl induced water stress

  7. Growth and Physiological Performance of Aerobic and Lowland Rice as Affected by Water Stress at Selected Growth Stages

    Directory of Open Access Journals (Sweden)

    Nadzariah Kamarul Zaman

    2018-03-01

    Full Text Available Aerobic rice technology is still new in Malaysia, and information regarding MARDI Aerob 1 (MA1, the first local aerobic rice variety, is still lacking. Therefore, comparative studies were carried out to determine the physiological performance of aerobic rice variety MA1 and lowland rice variety MR253 under water stress given at the panicle initiation, flowering and ripening stages. This experiment was arranged in a randomized complete block design. Stomatal conductance (gs, chlorophyll a fluorescence (Fv/Fm, leaf relative water content (leaf RWC, and soil moisture content (SMC as well as yield component parameters such as panicle number, grain yield and 100-grain weight were measured. Results revealed that gs and leaf RWC for both varieties decreased with depletion of SMC. The correlation study between the physiological parameters and SMC indicated that Fv/Fm was not affected by water stress, regardless of varieties. The yield components (panicle number, grain yield and 100-grain weight for both varieties greatly decreased when water stress was imposed at the panicle initiation stage. This study showed that the panicle initiation period was the most sensitive stage to water stress that contributed to a substantial reduction in yield for both varieties. Under the aerobic condition (control, MR253 produced higher panicle number, 100-grain weight and yield than MA1. Although MR253 is bred for lowland, it is well adapted to aerobic condition.

  8. mRNA-seq analysis of the Gossypium arboreum transcriptome reveals tissue selective signaling in response to water stress during seedling stage.

    Directory of Open Access Journals (Sweden)

    Xueyan Zhang

    Full Text Available The cotton diploid species, Gossypium arboreum, shows important properties of stress tolerance and good genetic stability. In this study, through mRNA-seq, we de novo assembled the unigenes of multiple samples with 3h H(2O, NaCl, or PEG treatments in leaf, stem and root tissues and successfully obtained 123,579 transcripts of G. arboreum, 89,128 of which were with hits through BLAST against known cotton ESTs and draft genome of G. raimondii. About 36,961 transcripts (including 1,958 possible transcription factor members were identified with differential expression under water stresses. Principal component analysis of differential expression levels in multiple samples suggested tissue selective signalling responding to water stresses. Venn diagram analysis showed the specificity and intersection of transcripts' response to NaCl and PEG treatments in different tissues. Self-organized mapping and hierarchical cluster analysis of the data also revealed strong tissue selectivity of transcripts under salt and osmotic stresses. In addition, the enriched gene ontology (GO terms for the selected tissue groups were differed, including some unique enriched GO terms such as photosynthesis and tetrapyrrole binding only in leaf tissues, while the stem-specific genes showed unique GO terms related to plant-type cell wall biogenesis, and root-specific genes showed unique GO terms such as monooxygenase activity. Furthermore, there were multiple hormone cross-talks in response to osmotic and salt stress. In summary, our multidimensional mRNA sequencing revealed tissue selective signalling and hormone crosstalk in response to salt and osmotic stresses in G. arboreum. To our knowledge, this is the first such report of spatial resolution of transcriptome analysis in G. arboreum. Our study will potentially advance understanding of possible transcriptional networks associated with water stress in cotton and other crop species.

  9. Grain boundary selective oxidation and intergranular stress corrosion crack growth of high-purity nickel binary alloys in high-temperature hydrogenated water

    Energy Technology Data Exchange (ETDEWEB)

    Bruemmer, S. M.; Olszta, M. J.; Toloczko, M. B.; Schreiber, D. K.

    2018-02-01

    The effects of alloying elements in Ni-5at%X binary alloys on intergranular (IG) corrosion and stress corrosion cracking (SCC) have been assessed in 300-360°C hydrogenated water at the Ni/NiO stability line. Alloys with Cr or Al additions exhibited grain boundary oxidation and IGSCC, while localized degradation was not observed for pure Ni, Ni-Cu or Ni-Fe alloys. Environment-enhanced crack growth was determined by comparing the response in water and N2 gas. Results demonstrate that selective grain boundary oxidation of Cr and Al promoted IGSCC of these Ni alloys in hydrogenated water.

  10. Water Stress Projection Modeling

    Science.gov (United States)

    2016-09-01

    water consumption stress in coming decades is electricity generation in two surrounding counties, El Paso and Doña Ana, which are expected to...better able to predict and prepare for a changing climate. Army installations will be affected by climate change. It behooves the Army to understand...stationing analysis, the resources ex- amined were: a. Training land b. Energy ( electricity and natural gas) c. Water and wastewater treatment and solid

  11. Adaptation of the chlorophycean Dictyosphaerium chlorelloides to stressful acidic, mine metal-rich waters as result of pre-selective mutations.

    Science.gov (United States)

    López-Rodas, Victoria; Marvá, Fernando; Rouco, Mónica; Costas, Eduardo; Flores-Moya, Antonio

    2008-06-01

    Several species of microalgae, closely related to mesophilic lineages, inhabit the extreme environment (pH 2.5, high levels of metals) of the Spain's Aguas Agrias Stream water (AASW). Consequently, AASW constitutes an interesting natural laboratory for analysis of adaptation by microalgae to extremely stressful conditions. To distinguish between the pre-selective or post-selective origin of adaptation processes allowing the existence of microalgae in AASW, a Luria-Delbrück fluctuation analysis was performed with the chlorophycean Dictyosphaerium chlorelloides isolated from non-acidic waters. In the analysis, AASW was used as selective factor. Preselective, resistant D. chlorelloides cells appeared with a frequency of 1.1 x 10(-6) per cell per generation. AASW-resistant mutants, with a diminished Malthusian fitness, are maintained in non-extreme waters as the result of a balance between new AASW-resistant cells arising by mutation and AASW-resistant mutants eliminated by natural selection (equilibrium at c. 12 AASW-resistants per 10(7) wild-type cells). We propose that the microalgae inhabiting this stressful environment could be the descendents of chance mutants that arrived in the past or are even arriving at the present.

  12. Underground water stress release models

    Science.gov (United States)

    Li, Yong; Dang, Shenjun; Lü, Shaochuan

    2011-08-01

    The accumulation of tectonic stress may cause earthquakes at some epochs. However, in most cases, it leads to crustal deformations. Underground water level is a sensitive indication of the crustal deformations. We incorporate the information of the underground water level into the stress release models (SRM), and obtain the underground water stress release model (USRM). We apply USRM to the earthquakes occurred at Tangshan region. The analysis shows that the underground water stress release model outperforms both Poisson model and stress release model. Monte Carlo simulation shows that the simulated seismicity by USRM is very close to the real seismicity.

  13. Physiological response of selected eragrostis species to water ...

    African Journals Online (AJOL)

    Physiological response of selected eragrostis species to water-deficit stress. ... performing crop variety of Eragrostis tef under this stress, the responses of two varieties, ... Comparative study of closely related plant species might be a better ...

  14. Selection of cDNAs differential fragments related to water stress in Ullucus tuberosus Loz. (Bassellaceae) «olluco»

    OpenAIRE

    Romero-Carpio, Mariela; Estrada-Jiménez, Rolando

    2013-01-01

    A partir de la expresión diferencial de ARNm de plántulas in vitro de dos accesiones de Ullucus tuberosus Loz. «olluco» altamente tolerantes a estrés osmótico, fueron seleccionados 31 fragmentos diferenciales de ADNc relacionados con tolerancia a sequía. Thirty-one differential fragments of cDNA related to drought tolerance have been selected from the mRNA differential expression of in vitro plantelets belonging to two accessions of Ullucus tuberosus Loz. «olluco» highly tolerant to osmoti...

  15. Use of crop water stress index for monitoring water stress in some sinanthropic plant species

    Directory of Open Access Journals (Sweden)

    Marinela Roxana ROŞESCU

    2010-11-01

    Full Text Available The water stress indicator (crop water stress index, CWSI is a measure of the transpiration rate of a plant, influenced by the leaf and air temperature difference from the plant’s vicinity and the air pressure deficit of the water vapors from the atmosphere. The experiments were realized in July-August 2008 and 2009 for six species in the cities Pitesti, Mioveni and Maracineni: Cichorium intybus L., Conyza canadensis (L. Cronq., Erigeron annuus L. (Pers., Lactuca serriola Torn., Polygonum aviculare L. and Echinochloa crus-galli (L. Beauv. For those species we calculated the CWSI to estimate the water stress on the selected plants in the urban environment conditions. The analyzed species were exposed to a less accentuated water stress while vegetating in the soil and to a more intense one they were grown in the asphalt cracks. Cichorium intybus had the smallest CWSI value (0.26 while Lactuca serriola the highest one (0.44.

  16. The selective addition of water

    NARCIS (Netherlands)

    Resch, V.; Hanefeld, U.

    2014-01-01

    Water is omnipresent and essential. Yet at the same time it is a rather unreactive molecule. The direct addition of water to C[double bond, length as m-dash]C double bonds is therefore a challenge not answered convincingly. In this perspective we critically evaluate the selectivity and the

  17. Plant responses to water stress

    Science.gov (United States)

    Kar, Rup Kumar

    2011-01-01

    Terrestrial plants most often encounter drought stress because of erratic rainfall which has become compounded due to present climatic changes.Responses of plants to water stress may be assigned as either injurious change or tolerance index. One of the primary and cardinal changes in response to drought stress is the generation of reactive oxygen species (ROS), which is being considered as the cause of cellular damage. However, recently a signaling role of such ROS in triggering the ROS scavenging system that may confer protection or tolerance against stress is emerging. Such scavenging system consists of antioxidant enzymes like SOD, catalase and peroxidases, and antioxidant compounds like ascorbate, reduced glutathione; a balance between ROS generation and scavenging ultimately determines the oxidative load. As revealed in case of defence against pathogen, signaling via ROS is initiated by NADPH oxidase-catalyzed superoxide generation in the apoplastic space (cell wall) followed by conversion to hydrogen peroxide by the activity of cell wall-localized SOD. Wall peroxidase may also play role in ROS generation for signaling. Hydrogen peroxide may use Ca2+ and MAPK pathway as downstream signaling cascade. Plant hormones associated with stress responses like ABA and ethylene play their role possibly via a cross talk with ROS towards stress tolerance, thus projecting a dual role of ROS under drought stress. PMID:22057331

  18. Selective intake of down-pit water and separating potable water from water-bearing seams at the Rydultowy mine

    Energy Technology Data Exchange (ETDEWEB)

    Musiolik, H; Sikora, A; Murek, R

    1987-06-01

    Discusses problems of pit water selection. Describes the method of water intake, down-pit transport, pumping the separated potable water and its treatment at the Rydultowy mine. Stresses the usefulness of pit water selection in view of the existing shortage of potable water. Geologic and mining conditions at the mine are described along with the amount of water influx into the mine. Advantages arising from mine water utilization are outlined.

  19. Selection of a Vegetable Water-Retaining Material and Its Effects on the Growth and Quality of Cucumber under Drought Stress Part 1 : Selection of a Vegetable Water-Retaining Material

    OpenAIRE

    Yang, Shang-Dong; Wang, Rui; Li, Gang; Egashira, Kazuhiko

    2008-01-01

    Water-retention capacities of moss, common water hyacinth and Late Juncellus were compared with that of SAP (super absorbent polymers), a presently used chemical water-retaining material. Moss was highest in the amount of water retained per unit weight among the three vegetable materials and showed a somewhat higher water-retention capacity than did SAP. However, it is difficult to collect moss enough for use as a water-retaining material, and collection of a large amount of moss easily lea...

  20. Effects of temperature and water stresses on germination of some ...

    African Journals Online (AJOL)

    Therefore, we opted for the Chetoui variety that better meets the conditions of stresses induced by low temperatures and water deficit. This best performing variety must have, throughout their development cycle, been tolerant to environmental stresses; which allows us to obtain early tools for discriminative selection between ...

  1. Grafting improves cucumber water stress tolerance in Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Abdulaziz R. Al-Harbi

    2018-02-01

    Full Text Available Water scarcity is a major limiting factor for crop productivity in arid and semi-arid areas. Grafting elite commercial cultivars onto selected vigorous rootstocks is considered as a useful strategy to alleviate the impact of environmental stresses. This study aims to investigate the feasibility of using grafting to improve fruit yield and quality of cucumber under water stress conditions. Alosama F1 cucumber cultivar (Cucumis sativus L. was grafted onto Affyne (Cucumis sativus L. and Shintoza A90 (Cucurbitamaxima × C. moschata rootstocks. Non-grafted plants were used as control. All genotypes were grown under three surface drip irrigation regimes: 50%, 75% and 100% of the crop evapotranspiration (ETc, which represent high-water stress, moderate-water stress and non-water stress conditions, respectively. Yield and fruit quality traits were analyzed and assessed. In comparison to the non-grafted plants, the best grafting treatment under water stress was Alosama F1 grafted onto Shintoza A90 rootstock. It had an overall improved yield and fruit quality under water stress owing to an increase in the total fruit yield by 27%, from 4.815 kg plant−1 in non-grafted treatment to 6.149 kg plant−1 in grafted treatment under moderate -water stress, total soluble solid contents (13%, titratable acidity (39% and vitamin C (33%. The soil water contents were low in soil surface and increase gradually with soil depth, while salt distribution showed an adverse trend. The positive effects of grafting on plant growth, productivity, and water use efficiency support this strategy as an useful tool for improving water stress tolerance in greenhouse grown cucumber in Saudi Arabia.

  2. Grafting improves cucumber water stress tolerance in Saudi Arabia.

    Science.gov (United States)

    Al-Harbi, Abdulaziz R; Al-Omran, Abdulrasoul M; Alharbi, Khadiga

    2018-02-01

    Water scarcity is a major limiting factor for crop productivity in arid and semi-arid areas. Grafting elite commercial cultivars onto selected vigorous rootstocks is considered as a useful strategy to alleviate the impact of environmental stresses. This study aims to investigate the feasibility of using grafting to improve fruit yield and quality of cucumber under water stress conditions. Alosama F 1 cucumber cultivar ( Cucumis sativus L.) was grafted onto Affyne ( Cucumis sativus L.) and Shintoza A90 ( Cucurbitamaxima × C. moschata ) rootstocks. Non-grafted plants were used as control. All genotypes were grown under three surface drip irrigation regimes: 50%, 75% and 100% of the crop evapotranspiration (ETc), which represent high-water stress, moderate-water stress and non-water stress conditions, respectively. Yield and fruit quality traits were analyzed and assessed. In comparison to the non-grafted plants, the best grafting treatment under water stress was Alosama F 1 grafted onto Shintoza A90 rootstock. It had an overall improved yield and fruit quality under water stress owing to an increase in the total fruit yield by 27%, from 4.815 kg plant -1 in non-grafted treatment to 6.149 kg plant -1 in grafted treatment under moderate -water stress, total soluble solid contents (13%), titratable acidity (39%) and vitamin C (33%). The soil water contents were low in soil surface and increase gradually with soil depth, while salt distribution showed an adverse trend. The positive effects of grafting on plant growth, productivity, and water use efficiency support this strategy as an useful tool for improving water stress tolerance in greenhouse grown cucumber in Saudi Arabia.

  3. Water stress detection using radar

    NARCIS (Netherlands)

    van Emmerik, T.H.M.

    2017-01-01

    Vegetation is a crucial part of the water and carbon cycle. Through photosynthesis carbon is assimilated for biomass production, and oxygen is released into the atmosphere. During this process, water is transpired through the stomata, and is redistributed in the plant. Transpired water is refilled

  4. Water requirements of selected industries

    Science.gov (United States)

    ,; Mussey, Orville D.; Conklin, Howard L.; Durfor, Charles N.; Otts, Louis Ethelbert; Walling, Faulkner B.

    1955-01-01

    The early industries in America generally were established when and where demands for the products of industry arose. Most of the early industries were so located that their increasing requirements for transportation, raw materials, market, labor, and water supply could be satisfied economically. Many of these original plant locations have continued as modern industrial centers and their output has increased manyfold in meeting the demands of our growing Nation. The recent and current industrial expansion and the trend toward the growth of chemical industries, many Of which are heavy users of water, has resulted in a tremendous increase in the total withdrawal of water for industrial use as well as a large increase in the per capita use of water. This increase in industrial water requirement has strained the capacity of the developed water supplies in many areas, and in some instances the adequacy of the potential water supplies is questionable. The Geological Survey is engaged in preparing and publishing a series of reports describing the developed and undeveloped water resources of many important industrial areas. This work was started initially at the request of the National Securities Resources Board as a means to insure that water supplies are adequate for our rapidly expanding industrial development. Although many factors contribute to establishing the feasibility or even the limits of future industrial development, the one relating to available water supply is extremely important. A knowledge of the water requirements of various industries is valuable therefore in planning the logical development in any area where water supply is a critical factor. Thus far very little suitable information on the water requirements of our major industries is available for general planning. An inventory of unit water-use values in industry therefore would be generally helpful and also might tend to stimulate water-conservation methods. To obtain such information

  5. Water Replacement Schedules in Heat Stress

    Science.gov (United States)

    Londeree, Ben R.; and others

    1969-01-01

    Although early ingestion of cold water appears to lead to greater relief from heat stress during physical exertion than late ingestion, this difference is reduced toward the end of an hour's work in high heat and humidity. (CK)

  6. Root water extraction under combined water and osmotic stress

    NARCIS (Netherlands)

    Jong van Lier, de Q.; Dam, van J.C.; Metselaar, K.

    2009-01-01

    Using a numerical implicit model for root water extraction by a single root in a symmetric radial flow problem, based on the Richards equation and the combined convection-dispersion equation, we investigated some aspects of the response of root water uptake to combined water and osmotic stress. The

  7. Water Stress in Global Transboundary River Basins: Significance of Upstream Water Use on Downstream Stress

    Science.gov (United States)

    Munia, H.; Guillaume, J. H. A.; Mirumachi, N.; Porkka,M.; Wada, Yoshihide; Kummu, M.

    2016-01-01

    Growing population and water demand have increased pressure on water resources in various parts of the globe, including many transboundary river basins. While the impacts of upstream water use on downstream water availability have been analyzed in many of these international river basins, this has not been systematically done at the global scale using coherent and comparable datasets. In this study, we aim to assess the change in downstream water stress due to upstream water use in the world's transboundary river basins. Water stress was first calculated considering only local water use of each sub-basin based on country-basin mesh, then compared with the situation when upstream water use was subtracted from downstream water availability. Wefound that water stress was generally already high when considering only local water use, affecting 0.95-1.44 billion people or 33%-51% of the population in transboundary river basins. After accounting for upstream water use, stress level increased by at least 1 percentage-point for 30-65 sub-basins, affecting 0.29-1.13 billion people. Altogether 288 out of 298 middle-stream and downstream sub-basin areas experienced some change in stress level. Further, we assessed whether there is a link between increased water stress due to upstream water use and the number of conflictive and cooperative events in the transboundary river basins, as captured by two prominent databases. No direct relationship was found. This supports the argument that conflicts and cooperation events originate from a combination of different drivers, among which upstream-induced water stress may play a role. Our findings contribute to better understanding of upstream-downstream dynamics in water stress to help address water allocation problems.

  8. Growth and physiological responses to water and nutrient stress in ...

    African Journals Online (AJOL)

    Growth and physiological responses to water and nutrient stress in oil palm. ... changes in growth, physiology and nutrient concentration in response to two watering regimes (well-watered and water-stress conditions) and ... from 32 Countries:.

  9. Assessing corn water stress using spectral reflectance

    Science.gov (United States)

    Mefford, Brenna S.

    Multiple remote sensing techniques have been developed to identify crop water stress, but some methods may be difficult for farmers to apply. Unlike most techniques, shortwave vegetation indices can be calculated using satellite, aerial, or ground imagery from the green (525-600 nm), red (625-700 nm), and near infrared (750-900 nm) spectral bands. If vegetation indices can be used to monitor crop water stress, growers could use this information as a quick low-cost guideline for irrigation management, thus helping save water by preventing over irrigating. This study occurred in the 2013 growing season near Greeley, CO, where pressurized drip irrigation was used to irrigate twelve corn ( Zea mays L.) treatments of varying water deficit. Multispectral data was collected and four different vegetation indices were evaluated: Normalized Difference Vegetation Index (NDVI), Optimized Soil-Adjusted Vegetation Index (OSAVI), Green Normalized Difference Vegetation Index (GNDVI), and the Wide Dynamic Range Vegetation Index (WDRVI). The four vegetation indices were compared to corn water stress as indicated by the stress coefficient (Ks) and water deficit in the root zone, calculated by using a water balance that monitors crop evapotranspiration (ET), irrigation events, precipitation events, and deep percolation. ET for the water balance was calculated using two different methods for comparison purposes: (1) calculation of the stress coefficient (Ks) using FAO-56 standard procedures; (2) use of canopy temperature ratio (Tc ratio) of a stressed crop to a non-stressed crop to calculate Ks. It was found that obtaining Ks from Tc ratio is a viable option, and requires less data to obtain than Ks from FAO-56. In order to compare the indices to Ks, vegetation ratios were developed in the process of normalization. Vegetation ratios are defined as the non-stressed vegetation index divided by the stressed vegetation index. Results showed that vegetation ratios were sensitive to water

  10. The effect of stress on men's food selection.

    Science.gov (United States)

    Zellner, Debra A; Saito, Shin; Gonzalez, Johanie

    2007-11-01

    This study investigates the effect of stress on food choice among men. Two groups of men were given either solvable (no-stress) or unsolvable (stress) anagrams to solve. Four bowls of snack foods-two healthy (peanuts and grapes) and two unhealthy (potato chips and M&M chocolate candies)-were available and subjects were invited to snack on them. Men in the no-stress group ate significantly more of the unhealthy foods than did men in the stress group. This finding is quite different from that found with women [Zellner et al. (2006). Food selection changes under stress. Physiology & Behavior, 87, 789-793]. Women tended to eat more grapes when not stressed than when stressed and more M&Ms when stressed than when not stressed. Thus, the effect of stress level on food choice is different for men and women.

  11. Strategy Guideline: Proper Water Heater Selection

    Energy Technology Data Exchange (ETDEWEB)

    Hoeschele, M. [Alliance for Residential Building Innovation, Davis, CA (United States); Springer, D. [Alliance for Residential Building Innovation, Davis, CA (United States); German, A. [Alliance for Residential Building Innovation, Davis, CA (United States); Staller, J. [Alliance for Residential Building Innovation, Davis, CA (United States); Zhang, Y. [Alliance for Residential Building Innovation, Davis, CA (United States)

    2015-04-01

    This Strategy Guideline on proper water heater selection was developed by the Building America team Alliance for Residential Building Innovation to provide step-by-step procedures for evaluating preferred cost-effective options for energy efficient water heater alternatives based on local utility rates, climate, and anticipated loads.

  12. Strategy Guideline. Proper Water Heater Selection

    Energy Technology Data Exchange (ETDEWEB)

    Hoeschele, M. [Alliance for Residential Building Innovation (ARBI), Davis, CA (United States); Springer, D. [Alliance for Residential Building Innovation (ARBI), Davis, CA (United States); German, A. [Alliance for Residential Building Innovation (ARBI), Davis, CA (United States); Staller, J. [Alliance for Residential Building Innovation (ARBI), Davis, CA (United States); Zhang, Y. [Alliance for Residential Building Innovation (ARBI), Davis, CA (United States)

    2015-04-09

    This Strategy Guideline on proper water heater selection was developed by the Building America team Alliance for Residential Building Innovation to provide step-by-step procedures for evaluating preferred cost-effective options for energy efficient water heater alternatives based on local utility rates, climate, and anticipated loads.

  13. Stress within a Restricted Time Window Selectively Affects the Persistence of Long-Term Memory

    Science.gov (United States)

    Fang, Qin; Chai, Ning; Zhao, Li-Yan; Xue, Yan-Xue; Luo, Yi-Xiao; Jian, Min; Han, Ying; Shi, Hai-Shui; Lu, Lin; Wu, Ping; Wang, Ji-Shi

    2013-01-01

    The effects of stress on emotional memory are distinct and depend on the stages of memory. Memory undergoes consolidation and reconsolidation after acquisition and retrieval, respectively. Stress facilitates the consolidation but disrupts the reconsolidation of emotional memory. Previous research on the effects of stress on memory have focused on long-term memory (LTM) formation (tested 24 h later), but the effects of stress on the persistence of LTM (tested at least 1 week later) are unclear. Recent findings indicated that the persistence of LTM requires late-phase protein synthesis in the dorsal hippocampus. The present study investigated the effect of stress (i.e., cold water stress) during the late phase after the acquisition and retrieval of contextual fear memory in rats. We found that stress and corticosterone administration during the late phase (12 h) after acquisition, referred to as late consolidation, selectively enhanced the persistence of LTM, whereas stress during the late phase (12 h) after retrieval, referred to as late reconsolidation, selectively disrupted the restabilized persistence of LTM. Moreover, the effects of stress on the persistence of LTM were blocked by the corticosterone synthesis inhibitor metyrapone, which was administered before stress, suggesting that the glucocorticoid system is involved in the effects of stress on the persistence of LTM. We conclude that stress within a restricted time window after acquisition or retrieval selectively affects the persistence of LTM and depends on the glucocorticoid system. PMID:23544051

  14. Light energy dissipation under water stress conditions

    International Nuclear Information System (INIS)

    Stuhlfauth, T.; Scheuermann, R.; Fock, H.P.

    1990-01-01

    Using 14 CO 2 gas exchange and metabolite analyses, stomatal as well as total internal CO 2 uptake and evolution were estimated. Pulse modulated fluorescence was measured during induction and steady state of photosynthesis. Leaf water potential of Digitalis lanata EHRH. plants decreased to -2.5 megapascals after withholding irrigation. By osmotic adjustment, leaves remained turgid and fully exposed to irradiance even at severe water stress. Due to the stress-induced reduction of stomatal conductance, the stomatal CO 2 exchange was drastically reduced, whereas the total CO 2 uptake and evolution were less affected. Stomatal closure induced an increase in the reassimilation of internally evolved CO 2 . This CO 2 -recycling consumes a significant amount of light energy in the form of ATP and reducing equivalents. As a consequence, the metabolic demand for light energy is only reduced by about 40%, whereas net photosynthesis is diminished by about 70% under severe stress conditions. By CO 2 recycling, carbon flux, enzymatic substrate turnover and consumption of light energy were maintained at high levels, which enabled the plant to recover rapidly after rewatering. In stressed D. lanata plants a variable fluorescence quenching mechanism, termed coefficient of actinic light quenching, was observed. Besides water conservation, light energy dissipation is essential and involves regulated metabolic variations

  15. Light energy dissipation under water stress conditions

    Energy Technology Data Exchange (ETDEWEB)

    Stuhlfauth, T.; Scheuermann, R.; Fock, H.P. (Universitaet Kaiserslautern (West Germany))

    1990-04-01

    Using {sup 14}CO{sub 2} gas exchange and metabolite analyses, stomatal as well as total internal CO{sub 2} uptake and evolution were estimated. Pulse modulated fluorescence was measured during induction and steady state of photosynthesis. Leaf water potential of Digitalis lanata EHRH. plants decreased to {minus}2.5 megapascals after withholding irrigation. By osmotic adjustment, leaves remained turgid and fully exposed to irradiance even at severe water stress. Due to the stress-induced reduction of stomatal conductance, the stomatal CO{sub 2} exchange was drastically reduced, whereas the total CO{sub 2} uptake and evolution were less affected. Stomatal closure induced an increase in the reassimilation of internally evolved CO{sub 2}. This CO{sub 2}-recycling consumes a significant amount of light energy in the form of ATP and reducing equivalents. As a consequence, the metabolic demand for light energy is only reduced by about 40%, whereas net photosynthesis is diminished by about 70% under severe stress conditions. By CO{sub 2} recycling, carbon flux, enzymatic substrate turnover and consumption of light energy were maintained at high levels, which enabled the plant to recover rapidly after rewatering. In stressed D. lanata plants a variable fluorescence quenching mechanism, termed coefficient of actinic light quenching, was observed. Besides water conservation, light energy dissipation is essential and involves regulated metabolic variations.

  16. Physiological Assessment of Water Stress in Potato Using Spectral Information.

    Science.gov (United States)

    Romero, Angela P; Alarcón, Andrés; Valbuena, Raúl I; Galeano, Carlos H

    2017-01-01

    Water stress in potato ( Solanum tuberosum L.) causes considerable losses in yield, and therefore, potato is often considered to be a drought sensitive crop. Identification of water deficit tolerant potato genotypes is an adaptation strategy to mitigate the climatic changes that are occurring in the Cundiboyacense region in Colombia. Previous studies have evaluated potato plants under water stress conditions using physiological analyses. However, these methodologies require considerable amounts of time and plant material to perform these measurements. This study evaluated and compared the physiological and spectral traits between two genotypes, Diacol Capiro and Perla Negra under two drought levels (10 and 15 days without irrigation from flowering). Reflectance information was used to calculate indexes which were associated with the physiological behavior in plants. The results showed that spectral information was correlated (ρ < 0.0001) with physiological variables such as foliar area (FA), total water content (H 2 Ot), relative growth rate of potato tubers (RGTtub), leaf area ratio (LAR), and foliar area index (AFI). In general, there was a higher concentration of chlorophyll under drought treatments. In addition, Perla Negra under water deficit treatments did not show significant differences in its physiological variables. Therefore, it could be considered a drought tolerant genotype because its physiological performance was not affected under water stress conditions. However, yield was affected in both genotypes after being subject to 15 days of drought. The results suggested that reflectance indexes are a useful and affordable approach for potato phenotyping to select parent and segregant populations in breeding programs.

  17. Global monthly water stress: II. Water demand and severity of water

    NARCIS (Netherlands)

    Wada, Y.; Beek, L.P.H. van; Viviroli, D.; Dürr, H.H.; Weingartner, R.; Bierkens, M.F.P.

    2011-01-01

    This paper assesses global water stress at a finer temporal scale compared to conventional assessments. To calculate time series of global water stress at a monthly time scale, global water availability, as obtained from simulations of monthly river discharge from the companion paper, is confronted

  18. Water stress induced changes in antioxidant enzymes, membrane ...

    African Journals Online (AJOL)

    PRECIOUS

    2009-12-01

    Dec 1, 2009 ... membrane stability index occurred under water stress. Accession 320 ... yielding wheat varieties for areas affected by water stress. (Mujtaba ...... Peroxidase activity in golden delicious apples as a ... Food Chem. 24: 200-201.

  19. Occupational Heat Stress Profiles in Selected Workplaces in India

    OpenAIRE

    Venugopal, Vidhya; Chinnadurai, Jeremiah S.; Lucas, Rebekah A. I.; Kjellstrom, Tord

    2016-01-01

    Health and productivity impacts from occupational heat stress have significant ramifications for the large workforce of India. This study profiled occupational heat stress impacts on the health and productivity of workers in select organized and unorganized Indian work sectors. During hotter and cooler seasons, Wet Bulb Globe Temperatures (WBGT) were used to quantify the risk of heat stress, according to International workplace guidelines. Questionnaires assessed workers' perceived health and...

  20. Stress Among Selected Library Practitioners in Nigerian: A ...

    African Journals Online (AJOL)

    Stress Among Selected Library Practitioners in Nigerian: A Diagnosis and ... situations and events at home and work place, in addition t, negative personal lifestyle. ... in productivity, quarrelsomeness, martial crises and in health complications.

  1. Corrosion and stress corrosion cracking in supercritical water

    Science.gov (United States)

    Was, G. S.; Ampornrat, P.; Gupta, G.; Teysseyre, S.; West, E. A.; Allen, T. R.; Sridharan, K.; Tan, L.; Chen, Y.; Ren, X.; Pister, C.

    2007-09-01

    Supercritical water (SCW) has attracted increasing attention since SCW boiler power plants were implemented to increase the efficiency of fossil-based power plants. The SCW reactor (SCWR) design has been selected as one of the Generation IV reactor concepts because of its higher thermal efficiency and plant simplification as compared to current light water reactors (LWRs). Reactor operating conditions call for a core coolant temperature between 280 °C and 620 °C at a pressure of 25 MPa and maximum expected neutron damage levels to any replaceable or permanent core component of 15 dpa (thermal reactor design) and 100 dpa (fast reactor design). Irradiation-induced changes in microstructure (swelling, radiation-induced segregation (RIS), hardening, phase stability) and mechanical properties (strength, thermal and irradiation-induced creep, fatigue) are also major concerns. Throughout the core, corrosion, stress corrosion cracking, and the effect of irradiation on these degradation modes are critical issues. This paper reviews the current understanding of the response of candidate materials for SCWR systems, focusing on the corrosion and stress corrosion cracking response, and highlights the design trade-offs associated with certain alloy systems. Ferritic-martensitic steels generally have the best resistance to stress corrosion cracking, but suffer from the worst oxidation. Austenitic stainless steels and Ni-base alloys have better oxidation resistance but are more susceptible to stress corrosion cracking. The promise of grain boundary engineering and surface modification in addressing corrosion and stress corrosion cracking performance is discussed.

  2. Welding residual stress improvement in internal components by water jet peening

    International Nuclear Information System (INIS)

    Enomoto, K.; Hirano, K.; Hayashi, M.; Hayashi, E.

    1996-01-01

    Cavitations are generated when highly pressurized water is jetted in water. Surface residual stress is improved remarkably due to the peening effect of extremely high pressure caused by the collapse of cavitation bubbles. This technique is called water jet peening (WJP). WJP is expected to be an effective maintenance technique for the prevention of stress corrosion cracking caused by residual stress in various components of power generating plants. Various kinds of specimens were water jet peened to evaluate the fundamental characteristics of WJP and to select the most appropriate conditions for the residual stress improvement. Test results showed that WJP markedly improved the tensile residual stress caused by welding and grinding to the high compressive residual stress and seems to prevent the stress corrosion cracking

  3. AFLP marker linked to water-stress-tolerant bulks in barley (Hordeum vulgare L.

    Directory of Open Access Journals (Sweden)

    A. Altinkut

    2003-01-01

    Full Text Available The amplified fragment length polymorphism (AFLP assay is an efficient method for the identification of molecular markers, useful in the improvement of numerous crop species. Bulked Segregant Analysis (BSA was used to identify AFLP markers associated with water-stress tolerance in barley, as this would permit rapid selection of water-stress tolerant genotypes in breeding programs. AFLP markers linked to water-stress tolerance was identified in two DNA pools (tolerant and sensitive, which were established using selected F2 individuals resulting from a cross between water-stress-tolerant and sensitive barley parental genotypes, based on their paraquat (PQ tolerance, leaf size, and relative water content (RWC. All these three traits were previously shown to be associated with water-stress tolerance in segregating F2 progeny of the barley cross used in a previous study. AFLP analysis was then performed on these DNA pools, using 40 primer pairs to detect AFLP fragments that are present/absent, respectively, in the two pools and their parental lines. One separate AFLP fragment, which was present in the tolerant parent and in the tolerant bulk, but absent in the sensitive parent and in the sensitive bulk, was identified. Polymorphism of the AFLP marker was tested among tolerant and sensitive F2 individuals. The presence of this marker that is associated with water-stress tolerance will greatly enhance selection for paraquat and water-stress tolerant genotypes in future breeding programs.

  4. Evaluation of Stress Loaded Steel Samples Using Selected Electromagnetic Methods

    International Nuclear Information System (INIS)

    Chady, T.

    2004-01-01

    In this paper the magnetic leakage flux and eddy current method were used to evaluate changes of materials' properties caused by stress. Seven samples made of ferromagnetic material with different level of applied stress were prepared. First, the leakage magnetic fields were measured by scanning the surface of the specimens with GMR gradiometer. Next, the same samples were evaluated using an eddy current sensor. A comparison between results obtained from both methods was carried out. Finally, selected parameters of the measured signal were calculated and utilized to evaluate level of the applied stress. A strong coincidence between amount of the applied stress and the maximum amplitude of the derivative was confirmed

  5. Plants in water-controlled ecosystems: active role in hydrologic processes and response to water stress. III. Vegetation water stress

    Science.gov (United States)

    Porporato, A.; Laio, F.; Ridolfi, L.; Rodriguez-Iturbe, I.

    The reduction of soil moisture content during droughts lowers the plant water potential and decreases transpiration; this in turn causes a reduction of cell turgor and relative water content which brings about a sequence of damages of increasing seriousness. A review of the literature on plant physiology and water stress shows that vegetation water stress can be assumed to start at the soil moisture level corresponding to incipient stomatal closure and reach a maximum intensity at the wilting point. The mean crossing properties of these soil moisture levels crucial for water stress are derived analytically for the stochastic model of soil moisture dynamics described in Part II (F. Laio, A. Porporato, L. Ridolfi, I. Rodriguez-Iturbe. Adv. Water Res. 24 (7) (2001) 707-723). These properties are then used to propose a measure of vegetation water stress which combines the mean intensity, duration, and frequency of periods of soil water deficit. The characteristics of vegetation water stress are then studied under different climatic conditions, showing how the interplay between plant, soil, and environment can lead to optimal conditions for vegetation.

  6. Survival strategies of plants during water stress

    International Nuclear Information System (INIS)

    Scheuermann, R.; Stuhlfauth, T.; Sueltemeyer, D.; Fock, H.

    1989-01-01

    Fluorescence and gas exchange of bean, maize, sunflower and wooly foxglove were simultaneously measured at 250 μmol quanta/m 2 /s. Under severe water stresses conditions about 40% of the photochemical energy was converted to heat at PS II. This is interpreted as a protective mechanism against photoinhibitory damage when net CO 2 uptake is reduced by about 70%. After 14 CO 2 gas exchange, only in bean was a homogeneous distribution of radioactivity over the leaf observed. In all other plants we found a patchy distribution of regions with either an intensive or a reduced gas exchange. We conclude that CO 2 -recycling (photorespiration and reassimilation) behind closed stomata also contributed to energy dissipation under severe stress conditions

  7. Operational decisionmaking and action selection under psychological stress in nuclear power plants

    International Nuclear Information System (INIS)

    Gertman, D.I.; Haney, L.N.; Jenkins, J.P.; Blackman, H.S.

    1985-05-01

    An extensive review of literature on individual and group performance and decisionmaking under psychological stress was conducted and summarized. Specific stress-related variables relevant to reactor operation were pinpointed and incorporated in an experiment to assess the performance of reactor operators under psychological stress. The decisionmaking performance of 24 reactor operators under differing levels of workload, conflicting information, and detail of available written procedures was assessed in terms of selecting immediate, subsequent, and nonapplicable actions in response to 12 emergency scenarios resulting from a severe seismic event at a pressurized water reactor. Specific personality characteristics of the operators suggested by the literature to be related to performance under stress were assessed and correlated to decisionmaking under stress. The experimental results were statistically analyzed, and findings indicated that operator decisionmaking under stress was more accurate under lower levels of workload, with the availability of detailed procedures, and in the presence of high conflicting information

  8. Wind Stress Variability Observed Over Coastal Waters

    Science.gov (United States)

    Ortiz-Suslow, D. G.; Haus, B. K.; Laxague, N.; Williams, N. J.; Graber, H. C.

    2016-02-01

    The wind stress on the ocean surface generates waves, drives currents, and enhances gas exchange; and a significant amount of work has been done to characterize the air-sea momentum flux in terms of bulk oceanographic and atmospheric parameters. However, the majority of this work to develop operational algorithms has been focused on the deep ocean and the suitability of these methods in the coastal regime has not been evaluated. The findings from a two-part field campaign will be presented which highlight the divergence of nearshore wind stress observations from conventional, deep water results. The first set of data comes from a coastal region near a relatively small, natural tidal inlet. A high degree of spatial variability was observed in both the wind stress magnitude and direction, suggestive of coastal processes (e.g., depth-limited wave affects and horizontal current shear) modulating the momentum flux from the atmosphere to the ocean surface. These shallow-water processes are typically not accounted for in conventional parameterizations. Across the experimental domain and for a given wind speed, the stress magnitude was found to be nearly 2.5 times that predicted by conventional methods; also, a high propensity for stress steering off the mean azimuthal wind direction (up to ±70 degrees) was observed and linked to horizontal current gradients produced by the tidal inlet. The preliminary findings from a second data set taken in the vicinity of the macrotidal Columbia River Mouth will also be presented. Compared to the first data set, a similar degree of variability is observed here, but the processes responsible for this are present at a much larger scale. Specifically, the Columbia River Mouth observations were made in the presence of significant swell wave energy and during periods of very high estuarine discharge. The relative angle between the wind and swell direction is expected to be significant with regards to the observed momentum flux. Also, these

  9. An Integrated Analysis of Changes in Water Stress in Europe

    DEFF Research Database (Denmark)

    Henrichs, T.; Lehner, B.; Alcamo, J.

    2002-01-01

    Future changes in water availability with climate change and changes in water use due to socio-economic development are to occur in parallel. In an integrated analysis we bring together these aspects of global change in a consistent manner, and analyse the water stress situation in Europe. We find...... that today high water stress exists in one-fifth of European river basin area. Under a scenario projection, increases in water use throughout Eastern Europe are accompanied by decreases in water availability in most of Southern Europe--combining these trends leads to a marked increase in water stress...

  10. Sex-specific selection under environmental stress in seed beetles.

    Science.gov (United States)

    Martinossi-Allibert, I; Arnqvist, G; Berger, D

    2017-01-01

    Sexual selection can increase rates of adaptation by imposing strong selection in males, thereby allowing efficient purging of the mutation load on population fitness at a low demographic cost. Indeed, sexual selection tends to be male-biased throughout the animal kingdom, but little empirical work has explored the ecological sensitivity of this sex difference. In this study, we generated theoretical predictions of sex-specific strengths of selection, environmental sensitivities and genotype-by-environment interactions and tested them in seed beetles by manipulating either larval host plant or rearing temperature. Using fourteen isofemale lines, we measured sex-specific reductions in fitness components, genotype-by-environment interactions and the strength of selection (variance in fitness) in the juvenile and adult stage. As predicted, variance in fitness increased with stress, was consistently greater in males than females for adult reproductive success (implying strong sexual selection), but was similar in the sexes in terms of juvenile survival across all levels of stress. Although genetic variance in fitness increased in magnitude under severe stress, heritability decreased and particularly so in males. Moreover, genotype-by-environment interactions for fitness were common but specific to the type of stress, sex and life stage, suggesting that new environments may change the relative alignment and strength of selection in males and females. Our study thus exemplifies how environmental stress can influence the relative forces of natural and sexual selection, as well as concomitant changes in genetic variance in fitness, which are predicted to have consequences for rates of adaptation in sexual populations. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

  11. Critical water stress levels in Pinus patula seedlings and their ...

    African Journals Online (AJOL)

    Critical water stress levels in Pinus patula seedlings and their relation to measures of seedling morphology. ... Southern Forests: a Journal of Forest Science ... A pot trial was implemented to determine the effect of soil water stress following transplanting on shoot water potential and stomatal conductance of Pinus patula ...

  12. Water stress, water salience, and the implications for water supply planning

    Science.gov (United States)

    Garcia, M. E.; Islam, S.

    2017-12-01

    Effectively addressing the water supply challenges posed by urbanization and climate change requires a holistic understanding of the water supply system, including the impact of human behavior on system dynamics. Decision makers have limits to available information and information processing capacity, and their attention is not equally distributed among risks. The salience of a given risk is higher when increased attention is directed to it and though perceived risk may increase, real risk does not change. Relevant to water supply planning is how and when water stress results in an increased salience of water risks. This work takes a socio-hydrological approach to develop a water supply planning model that includes water consumption as an endogenous variable, in the context of Las Vegas, NV. To understand the benefits and limitations of this approach, this model is compared to a traditional planning model that uses water consumption scenarios. Both models are applied to project system reliability and water stress under four streamflow and demographic scenarios, and to assess supply side responses to changing conditions. The endogenous demand model enables the identification of feedback between both supply and demand management decisions on future water consumption and system performance. This model, while specific to the Las Vegas case, demonstrates a prototypical modeling framework capable of examining water-supply demand interactions by incorporating water stress driven conservation.

  13. Stress improves selective attention towards emotionally neutral left ear stimuli.

    Science.gov (United States)

    Hoskin, Robert; Hunter, M D; Woodruff, P W R

    2014-09-01

    Research concerning the impact of psychological stress on visual selective attention has produced mixed results. The current paper describes two experiments which utilise a novel auditory oddball paradigm to test the impact of psychological stress on auditory selective attention. Participants had to report the location of emotionally-neutral auditory stimuli, while ignoring task-irrelevant changes in their content. The results of the first experiment, in which speech stimuli were presented, suggested that stress improves the ability to selectively attend to left, but not right ear stimuli. When this experiment was repeated using tonal stimuli the same result was evident, but only for female participants. Females were also found to experience greater levels of distraction in general across the two experiments. These findings support the goal-shielding theory which suggests that stress improves selective attention by reducing the attentional resources available to process task-irrelevant information. The study also demonstrates, for the first time, that this goal-shielding effect extends to auditory perception. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Selected techniques in water resources investigations, 1965

    Science.gov (United States)

    Mesnier, Glennon N.; Chase, Edith B.

    1966-01-01

    Increasing world activity in water-resources development has created an interest in techniques for conducting investigations in the field. In the United States, the Geological Survey has the responsibility for extensive and intensive hydrologic studies, and the Survey places considerable emphasis on discovering better ways to carry out its responsibility. For many years, the dominant interest in field techniques has been "in house," but the emerging world interest has led to a need for published accounts of this progress. In 1963 the Geological Survey published "Selected Techniques in Water Resources Investigations" (Water-Supply Paper 1669-Z) as part of the series "Contributions to the Hydrology of the United States."The report was so favorably received that successive volumes are planned, of which this is the first. The present report contains 25 papers that represent new ideas being tested or applied in the hydrologic field program of the Geological Survey. These ideas range from a proposed system for monitoring fluvial sediment to how to construct stream-gaging wells from steel oil drums. The original papers have been revised and edited by the compilers, but the ideas presented are those of the authors. The general description of the bubble gage on page 2 has been given by the compilers as supplementary information.

  15. Crop yield response to water stress imposed at different growth stages

    International Nuclear Information System (INIS)

    Iqbal, M.; Mahmood Shah, M.; Wisal, M.

    1995-01-01

    Potato requires sufficient soil moisture and fertilization to produce high yields but the present water resoures are limited compared to the cultivable land, field experiments were conduced from 1991 to 1995 to study relationship between yield and crop water use as a function of water stress imposed at different growth stages. The irrigation treatments involved application of full and stress watering s selectively at four growth stages : Establishment , Flowering Tuber formation and ripening. In full watering, full water requirements of the crop were met, i.e., ET sub a = ET sub m whereas in stress watering about half the amount of full watering was applied, i.e., ET sub a < ET sub m. Changes in moisture content of the soil pre files after irrigation were monitored with the help of neutron moisture probe in order to compute ET sub a by the water balance method. The results obtained showed that the tuber yield was produced by full watering ( T 1) and the lowest by continuous stress watering (T 2). A plot of relative yield against relative evapotranspiration deficit revealed that ripening was the lest sensitive whereas early development followed by flowering the most sensitive growth stage to water stress. The crop water use efficiencies were generally higher in the treatments where a combination of normal and stress watering was applied compared to where all - normal watering s were applied. The traditional irrigation practice resulted in wasteful water application with relatively lower yields, hence the results from this project will have high value for the farming community to get this higher yields with scarce water resources. The studies with labelled fertilizer showed that planting and earthing - up were equally important growth stages of potato for applying fertilizer for its efficient utilization. 3 figs; 25 tabs; 12 refs (Author)

  16. Space Station Freedom regenerative water recovery system configuration selection

    Science.gov (United States)

    Reysa, R.; Edwards, J.

    1991-01-01

    The Space Station Freedom (SSF) must recover water from various waste water sources to reduce 90 day water resupply demands for a four/eight person crew. The water recovery system options considered are summarized together with system configuration merits and demerits, resource advantages and disadvantages, and water quality considerations used to select the SSF water recovery system.

  17. Occupational Heat Stress Profiles in Selected Workplaces in India.

    Science.gov (United States)

    Venugopal, Vidhya; Chinnadurai, Jeremiah S; Lucas, Rebekah A I; Kjellstrom, Tord

    2015-12-29

    Health and productivity impacts from occupational heat stress have significant ramifications for the large workforce of India. This study profiled occupational heat stress impacts on the health and productivity of workers in select organized and unorganized Indian work sectors. During hotter and cooler seasons, Wet Bulb Globe Temperatures (WBGT) were used to quantify the risk of heat stress, according to International workplace guidelines. Questionnaires assessed workers' perceived health and productivity impacts from heat stress. A total of 442 workers from 18 Indian workplaces participated (22% and 78% from the organized and unorganized sector, respectively). Overall 82% and 42% of workers were exposed to higher than recommended WBGT during hotter and cooler periods, respectively. Workers with heavy workloads reported more heat-related health issues (chi square = 23.67, p ≤ 0.001) and reduced productivity (chi square = 15.82, p ≤ 0.001), especially the outdoor workers. Heat-rashes, dehydration, heat-syncope and urinogenital symptoms were self-reported health issues. Cited reasons for productivity losses were: extended-work hours due to fatigue/exhaustion, sickness/hospitalization and wages lost. Reducing workplace heat stress will benefit industries and workers via improving worker health and productivity. Adaptation and mitigation measures to tackle heat stress are imperative to protect the present and future workforce as climate change progresses.

  18. Occupational Heat Stress Profiles in Selected Workplaces in India

    Science.gov (United States)

    Venugopal, Vidhya; Chinnadurai, Jeremiah S.; Lucas, Rebekah A. I.; Kjellstrom, Tord

    2015-01-01

    Health and productivity impacts from occupational heat stress have significant ramifications for the large workforce of India. This study profiled occupational heat stress impacts on the health and productivity of workers in select organized and unorganized Indian work sectors. During hotter and cooler seasons, Wet Bulb Globe Temperatures (WBGT) were used to quantify the risk of heat stress, according to International workplace guidelines. Questionnaires assessed workers’ perceived health and productivity impacts from heat stress. A total of 442 workers from 18 Indian workplaces participated (22% and 78% from the organized and unorganized sector, respectively). Overall 82% and 42% of workers were exposed to higher than recommended WBGT during hotter and cooler periods, respectively. Workers with heavy workloads reported more heat-related health issues (chi square = 23.67, p ≤ 0.001) and reduced productivity (chi square = 15.82, p ≤ 0.001), especially the outdoor workers. Heat-rashes, dehydration, heat-syncope and urinogenital symptoms were self-reported health issues. Cited reasons for productivity losses were: extended-work hours due to fatigue/exhaustion, sickness/hospitalization and wages lost. Reducing workplace heat stress will benefit industries and workers via improving worker health and productivity. Adaptation and mitigation measures to tackle heat stress are imperative to protect the present and future workforce as climate change progresses. PMID:26729144

  19. Physical and virtual water transfers for regional water stress alleviation in China.

    Science.gov (United States)

    Zhao, Xu; Liu, Junguo; Liu, Qingying; Tillotson, Martin R; Guan, Dabo; Hubacek, Klaus

    2015-01-27

    Water can be redistributed through, in physical terms, water transfer projects and virtually, embodied water for the production of traded products. Here, we explore whether such water redistributions can help mitigate water stress in China. This study, for the first time to our knowledge, both compiles a full inventory for physical water transfers at a provincial level and maps virtual water flows between Chinese provinces in 2007 and 2030. Our results show that, at the national level, physical water flows because of the major water transfer projects amounted to 4.5% of national water supply, whereas virtual water flows accounted for 35% (varies between 11% and 65% at the provincial level) in 2007. Furthermore, our analysis shows that both physical and virtual water flows do not play a major role in mitigating water stress in the water-receiving regions but exacerbate water stress for the water-exporting regions of China. Future water stress in the main water-exporting provinces is likely to increase further based on our analysis of the historical trajectory of the major governing socioeconomic and technical factors and the full implementation of policy initiatives relating to water use and economic development. Improving water use efficiency is key to mitigating water stress, but the efficiency gains will be largely offset by the water demand increase caused by continued economic development. We conclude that much greater attention needs to be paid to water demand management rather than the current focus on supply-oriented management.

  20. Water stress induces overexpression of superoxide dismutases that ...

    African Journals Online (AJOL)

    Water stress is known to induce active oxygen species in plants. The accumulation of these harmful species must be prevented by plants as rapidly as possible to maintain growth and productivity. The aim of this study was to determine the effect of water stress on superoxide dismutase isozymes (SOD, EC 1.15.1.1.) in two ...

  1. Effect of progressive water deficit stress on proline accumulation and ...

    African Journals Online (AJOL)

    Water deficit stress is one of the important factors limiting chickpea production in arid and semi-arid regions of West Asia and North Africa. When water deficit stress is imposed, different molecular and biochemical responses take place. This study was carried out to investigate proline accumulation and protein profiles of ...

  2. MONITORING ON PLANT LEAF WATER POTENTIAL USING NIR SPECTROSCOPY FOR WATER STRESS MANAGEMENT

    Directory of Open Access Journals (Sweden)

    Diding Suhandy

    2012-12-01

    Full Text Available The performance of the calibration model with temperature compensation for on-plant leaf water potential (LWP determination in tomato plants was evaluated. During a cycle of water stress, the on-plant LWP measurement was conducted. The result showed that the LWP values under water stress and recovery from water stress could be monitored well. It showed that a real time monitoring of the LWP values using NIR spectroscopy could be possible.   Keywords: water stress, real time monitoring of leaf water potential, NIR spectroscopy, plant response-based

  3. Impact of emerging clean vehicle system on water stress

    International Nuclear Information System (INIS)

    Cai, Hua; Hu, Xiaojun; Xu, Ming

    2013-01-01

    Graphical abstract: Display Omitted - Highlights: • Clean vehicles may increase US water consumption up to 2810 billion gallons/year. • Large-scale clean vehicle adoption could lead to severe regional water stress. • Fuel choice for clean vehicle is crucial in minimizing regional water stress. • Regional optimization illustrated the importance of regional consideration. - Abstract: While clean vehicles (i.e., vehicles powered by alternative fuels other than fossil fuels) offer great potential to reduce greenhouse gas emissions from gasoline-based vehicles, the associated impact on water resources has not yet been fully assessed. This research provides a systematic evaluation of the impact of a fully implemented clean vehicle system on national and state-level water demand and water stress. On the national level, based on existing policies, transitioning the current gasoline-based transportation into one with clean vehicles will increase national annual water consumption by 1950–2810 billion gallons of water, depending on the market penetration of electric vehicles. On the state level, variances of water efficiency in producing different fuels are significant. The fuel choice for clean vehicle development is especially crucial for minimizing water stress increase in states with already high water stress, high travel demands, and significant variations in water efficiency in producing different alternative fuels. Current development of clean vehicle infrastructure, however, has not reflected these state-level variations. This study takes an optimization approach to further evaluate impacts on state-level water stress from a fully implemented clean vehicle system and identified potential roles (fuel producer or consumer) states may play in real world clean vehicle development scenario. With an objective of minimizing overall water stress impact, our optimization model aims to provide an analytical framework to better assess impacts on state-level water

  4. Stress responsiveness predicts individual variation in mate selectivity.

    Science.gov (United States)

    Vitousek, Maren N; Romero, L Michael

    2013-06-15

    Steroid hormones, including glucocorticoids, mediate a variety of behavioral and physiological processes. Circulating hormone concentrations vary substantially within populations, and although hormone titers predict reproductive success in several species, little is known about how individual variation in circulating hormone concentrations is linked with most reproductive behaviors in free-living organisms. Mate choice is an important and often costly component of reproduction that also varies substantially within populations. We examined whether energetically costly mate selection behavior in female Galápagos marine iguanas (Amblyrhynchus cristatus) was associated with individual variation in the concentrations of hormones previously shown to differ between reproductive and non-reproductive females during the breeding season (corticosterone and testosterone). Stress-induced corticosterone levels - which are suppressed in female marine iguanas during reproduction - were individually repeatable throughout the seven-week breeding period. Mate selectivity was strongly predicted by individual variation in stress-induced corticosterone: reproductive females that secreted less corticosterone in response to a standardized stressor assessed more displaying males. Neither baseline corticosterone nor testosterone predicted variation in mate selectivity. Scaled body mass was not significantly associated with mate selectivity, but females that began the breeding period in lower body condition showed a trend towards being less selective about potential mates. These results provide the first evidence that individual variation in the corticosterone stress response is associated with how selective females are in their choice of a mate, an important contributor to fitness in many species. Future research is needed to determine the functional basis of this association, and whether transient acute increases in circulating corticosterone directly mediate mate choice behaviors

  5. Systems responses to progressive water stress in durum wheat.

    Directory of Open Access Journals (Sweden)

    Dimah Z Habash

    Full Text Available Durum wheat is susceptible to terminal drought which can greatly decrease grain yield. Breeding to improve crop yield is hampered by inadequate knowledge of how the physiological and metabolic changes caused by drought are related to gene expression. To gain better insight into mechanisms defining resistance to water stress we studied the physiological and transcriptome responses of three durum breeding lines varying for yield stability under drought. Parents of a mapping population (Lahn x Cham1 and a recombinant inbred line (RIL2219 showed lowered flag leaf relative water content, water potential and photosynthesis when subjected to controlled water stress time transient experiments over a six-day period. RIL2219 lost less water and showed constitutively higher stomatal conductance, photosynthesis, transpiration, abscisic acid content and enhanced osmotic adjustment at equivalent leaf water compared to parents, thus defining a physiological strategy for high yield stability under water stress. Parallel analysis of the flag leaf transcriptome under stress uncovered global trends of early changes in regulatory pathways, reconfiguration of primary and secondary metabolism and lowered expression of transcripts in photosynthesis in all three lines. Differences in the number of genes, magnitude and profile of their expression response were also established amongst the lines with a high number belonging to regulatory pathways. In addition, we documented a large number of genes showing constitutive differences in leaf transcript expression between the genotypes at control non-stress conditions. Principal Coordinates Analysis uncovered a high level of structure in the transcriptome response to water stress in each wheat line suggesting genome-wide co-ordination of transcription. Utilising a systems-based approach of analysing the integrated wheat's response to water stress, in terms of biological robustness theory, the findings suggest that each durum

  6. Differential response to water deficit stress in alfalfa ( Medicago ...

    African Journals Online (AJOL)

    The present study was fixed as objective to compare the response to water deficit (33% of field capacity, FC) stress of eight cultivars of Medicago sativa, originating from the Mediterranean basin. Comparison was performed on some key parameters such as growth, relative water content, leaf water potential, MDA tissue ...

  7. Selective neuronal vulnerability to oxidative stress in the brain

    Directory of Open Access Journals (Sweden)

    Xinkun Wang

    2010-03-01

    Full Text Available Oxidative stress (OS, caused by the imbalance between the generation and detoxification of reactive oxygen and nitrogen species (ROS/RNS, plays an important role in brain aging, neurodegenerative diseases, and other related adverse conditions, such as ischemia. While ROS/RNS serve as signaling molecules at physiological levels, an excessive amount of these molecules leads to oxidative modification and, therefore, dysfunction of proteins, nucleic acids, and lipids. The response of neurons to this pervasive stress, however, is not uniform in the brain. While many brain neurons can cope with a rise in OS, there are select populations of neurons in the brain that are vulnerable. Because of their selective vulnerability, these neurons are usually the first to exhibit functional decline and cell death during normal aging, or in age-associated neurodegenerative diseases, such as Alzheimer’s disease. Understanding the molecular and cellular mechanisms of selective neuronal vulnerability (SNV to OS is important in the development of future intervention approaches to protect such vulnerable neurons from the stresses of the aging process and the pathological states that lead to neurodegeneration. In this review, the currently known molecular and cellular factors that contribute to SNV to OS are summarized. Included among the major underlying factors are high intrinsic OS, high demand for ROS/RNS-based signaling, low ATP production, mitochondrial dysfunction, and high inflammatory response in vulnerable neurons. The contribution to the selective vulnerability of neurons to OS by other intrinsic or extrinsic factors, such as deficient DNA damage repair, low calcium-buffering capacity, and glutamate excitotoxicity, are also discussed.

  8. Water Quality Assessment of Selected Domestic Water Sources

    African Journals Online (AJOL)

    Nwokem et al.

    @yahoo.com ... were collected in clean sterilized plastic bottles in the rainy ... centers often depend on the water vendors for domestic water supply ... MATERIALS AND METHODS .... water balance problems for individual aquatic organisms.

  9. Mechanical stress-controlled tunable active frequency-selective surface

    Science.gov (United States)

    Huang, Bo-Cin; Hong, Jian-Wei; Lo, Cheng-Yao

    2017-01-01

    This study proposes a tunable active frequency-selective surface (AFSS) realized by mechanically expanding or contracting a split-ring resonator (SRR) array. The proposed AFSS transfers mechanical stress from its elastic substrate to the top of the SRR, thereby achieving electromagnetic (EM) modulation without the need for an additional external power supply, meeting the requirements for the target application: the invisibility cloak. The operating mechanism of the proposed AFSS differs from those of other AFSSs, supporting modulations in arbitrary frequencies in the target range. The proposed stress-controlled or strain-induced EM modulation proves the existence of an identical and linear relationship between the strain gradient and the frequency shift, implying its suitability for other EM modulation ranges and applications.

  10. Effect of water deficit stress on proline contents, soluble sugars ...

    African Journals Online (AJOL)

    Effect of water deficit stress on proline contents, soluble sugars, chlorophyll and grain yield of sunflower ... Journal Home > Vol 11, No 1 (2012) > ... The objective of the present work was to determine the mechanisms of tolerance of four ...

  11. Water quality assessment of selected domestic water sources in ...

    African Journals Online (AJOL)

    However, lead ion appears higher than the approved WHO and SON standard for water quality in all the sources except that of water vendors which is 0.04mg/l. It is therefore recommended that periodic monitoring of water quality, effective waste management system to improve the general water quality in the town, and ...

  12. Water stress induces overexpression of superoxide dismutases that ...

    African Journals Online (AJOL)

    SERVER

    2007-09-05

    Sep 5, 2007 ... Water stress is known to induce active oxygen species in plants. ... photosystem II photochemistry and whole plant growth against oxidative stress in these plants. ..... CO2. Plant Physiol. 110: 393-402. Sen Gupta A, Heinen JL, ...

  13. Water stress effects on spatially referenced cotton crop canopy properties

    Science.gov (United States)

    rop canopy temperature is known to be affected by water stress. Canopy reflectance can also be impacted as leaf orientation and color respond to the stress. As sensor systems are investigated for real-time management of irrigation and nitrogen, it is essential to understand how the data from the sen...

  14. Transient water stress in a vegetation canopy - Simulations and measurements

    Science.gov (United States)

    Carlson, Toby N.; Belles, James E.; Gillies, Robert R.

    1991-01-01

    Consideration is given to observational and modeling evidence of transient water stress, the effects of the transpiration plateau on the canopy radiometric temperature, and the factors responsible for the onset of the transpiration plateau, such as soil moisture. Attention is also given to the point at which the transient stress can be detected by remote measurement of surface temperature.

  15. Multi-modal sensor system for plant water stress assessment

    Science.gov (United States)

    Plant stress critically affects plant growth and causes significant loss of productivity and quality. When the plant is under water stress, it impedes photosynthesis and transpiration, resulting in changes in leaf color and temperature. Leaf discoloration in photosynthesis can be assessed by measu...

  16. Cytokinin Activity in Water-stressed Shoots 1

    Science.gov (United States)

    Itai, Chanan; Vaadia, Yoash

    1971-01-01

    Water stress applied to the plant shoot through enhanced evaporative demands reduced cytokinin activity in extracts of xylem exudate and leaves. This reduction resembled the changes in cytokinin activity caused by water stress applied to the root. Cytokinin activity in detached wilting leaves decreased rapidly. Recovery took place after several hours in a humid chamber. Experiments with 14C-kinetin indicated that the mechanism of the inactivation and its reversal involve a chemical transformation of the cytokinin molecule. PMID:16657585

  17. Spectral reflectance relationships to leaf water stress

    Science.gov (United States)

    Ripple, William J.

    1986-01-01

    Spectral reflectance data were collected from detached snapbean leaves in the laboratory with a multiband radiometer. Four experiments were designed to study the spectral response resulting from changes in leaf cover, relative water content of leaves, and leaf water potential. Spectral regions included in the analysis were red (630-690 nm), NIR (760-900 nm), and mid-IR (2.08-2.35 microns). The red and mid-IR bands showed sensitivity to changes in both leaf cover and relative water content of leaves. The NIR was only highly sensitive to changes in leaf cover. Results provided evidence that mid-IR reflectance was governed primarily by leaf moisture content, although soil reflectance was an important factor when leaf cover was less than 100 percent. High correlations between leaf water potentials and reflectance were attributed to covariances with relative water content of leaves and leaf cover.

  18. Adaptive value of phenological traits in stressful environments: predictions based on seed production and laboratory natural selection.

    Directory of Open Access Journals (Sweden)

    Benjamin Brachi

    Full Text Available Phenological traits often show variation within and among natural populations of annual plants. Nevertheless, the adaptive value of post-anthesis traits is seldom tested. In this study, we estimated the adaptive values of pre- and post-anthesis traits in two stressful environments (water stress and interspecific competition, using the selfing annual species Arabidopsis thaliana. By estimating seed production and by performing laboratory natural selection (LNS, we assessed the strength and nature (directional, disruptive and stabilizing of selection acting on phenological traits in A. thaliana under the two tested stress conditions, each with four intensities. Both the type of stress and its intensity affected the strength and nature of selection, as did genetic constraints among phenological traits. Under water stress, both experimental approaches demonstrated directional selection for a shorter life cycle, although bolting time imposes a genetic constraint on the length of the interval between bolting and anthesis. Under interspecific competition, results from the two experimental approaches showed discrepancies. Estimation of seed production predicted directional selection toward early pre-anthesis traits and long post-anthesis periods. In contrast, the LNS approach suggested neutrality for all phenological traits. This study opens questions on adaptation in complex natural environment where many selective pressures act simultaneously.

  19. Effectiveness of Stability Indices for Bread Wheat Genotypes Selection to Water Deficit Tolerant

    Directory of Open Access Journals (Sweden)

    A Naderi

    2013-12-01

    Full Text Available In countries such as Iran which will be faced water deficit as the main challenge in the future and the food production is going to be dependent to water recourses, wheat water-deficit tolerant and adapted genotypes release is one of the most important strategies under such a condition. In order to study the adaptation and terminal water deficit stress tolerance, fifteen bread wheat lines and Chamran cultivar as the check were evaluated. This research was carried out at Ahvaz, Dezfool, Zabol and Darab, south warm region research stations, in 2007-08 and 2008-09, in two separated experiments (1-well-watered and 2- terminal water deficit stress, using complete randomized block design with three replications. Data were analyzed and genotypes response was evaluated based on tolerance indices. Results showed that the difference among stations, years, genotypes and double and triple effects of source variations were significant at 1% probability level. Mean grain yield was 4300 Kg/ha in first year, while grain yield increased significantly in second year and reached to 5692 Kg/ha. Mean grain yield were 5840 and 4591Kg/ha under well-watered and terminal water deficit stress conditions, respectively. Correlation coefficients among STI, GMP ،MP and K1STI were significant. Correlation coefficient between slop of linear regression of grain yield in response to drought stress intensity and grain yield under terminal water deficit stress was positively and, with K2STI, TOL and SSI was negatively significant. Grain yield index, (YIR the proportion of grain yield of each genotype to grand mean of grain yield of all genotypes was the most important components to define grain yield in stepwise regression under both experiment conditions. According to the results of this research and based on tolerance indices, lines No. 2, 14 and 15 were selected as the high potential- terminal water deficit stress tolerant genotypes.

  20. Drought genetics have varying influence on corn water stress under differing water availability

    Science.gov (United States)

    Irrigated corn (Zea mays L.) in the Great Plains will be increasingly grown under limited irrigation management and greater water stress. Hybrids with drought genetics may decrease the impacts of water stress on yield. The objective of this experiment was to evaluate the effect of drought genetics o...

  1. Pure culture response of ectomycorrhizal fungi to imposed water stress

    Science.gov (United States)

    Mark D. Coleman; Caroline S. Bledsoe; William Lopushinsky

    1989-01-01

    The ability of ectomycorrhizal fungal isolates to tolerate imposed water stress in pure culture was examined in 55 isolates of 18 species. Water potential treatments, adjusted with polyethylene glycol, were applied to Petri dish units. These units allowed colony diameter measurements of fungi grown on liquid media. Delayed growth initiation and inhibition of growth...

  2. Growth and physiological responses to water and nutrient stress in ...

    African Journals Online (AJOL)

    Administrator

    2011-09-07

    Sep 7, 2011 ... water and nutrient stress made significant effects on nitrogen and phosphorus concentration, but no .... Measurements of relative water content (RWC), leaf relative ... C1 is the electrical conductivity value of samples at the first .... biomass, root, stem and leaf mass) were significant. ..... Plant, Cell and Environ.

  3. Electrodermal Activity Is Sensitive to Cognitive Stress under Water.

    Science.gov (United States)

    Posada-Quintero, Hugo F; Florian, John P; Orjuela-Cañón, Alvaro D; Chon, Ki H

    2017-01-01

    When divers are at depth in water, the high pressure and low temperature alone can cause severe stress, challenging the human physiological control systems. The addition of cognitive stress, for example during a military mission, exacerbates the challenge. In these conditions, humans are more susceptible to autonomic imbalance. Reliable tools for the assessment of the autonomic nervous system (ANS) could be used as indicators of the relative degree of stress a diver is experiencing, which could reveal heightened risk during a mission. Electrodermal activity (EDA), a measure of the changes in conductance at the skin surface due to sweat production, is considered a promising alternative for the non-invasive assessment of sympathetic control of the ANS. EDA is sensitive to stress of many kinds. Therefore, as a first step, we tested the sensitivity of EDA, in the time and frequency domains, specifically to cognitive stress during water immersion of the subject (albeit with their measurement finger dry for safety). The data from 14 volunteer subjects were used from the experiment. After a 4-min adjustment and baseline period after being immersed in water, subjects underwent the Stroop task, which is known to induce cognitive stress. The time-domain indices of EDA, skin conductance level (SCL) and non-specific skin conductance responses (NS.SCRs), did not change during cognitive stress, compared to baseline measurements. Frequency-domain indices of EDA, EDASymp (based on power spectral analysis) and TVSymp (based on time-frequency analysis), did significantly change during cognitive stress. This leads to the conclusion that EDA, assessed by spectral analysis, is sensitive to cognitive stress in water-immersed subjects, and can potentially be used to detect cognitive stress in divers.

  4. Electrodermal Activity Is Sensitive to Cognitive Stress under Water

    Directory of Open Access Journals (Sweden)

    Hugo F. Posada-Quintero

    2018-01-01

    Full Text Available When divers are at depth in water, the high pressure and low temperature alone can cause severe stress, challenging the human physiological control systems. The addition of cognitive stress, for example during a military mission, exacerbates the challenge. In these conditions, humans are more susceptible to autonomic imbalance. Reliable tools for the assessment of the autonomic nervous system (ANS could be used as indicators of the relative degree of stress a diver is experiencing, which could reveal heightened risk during a mission. Electrodermal activity (EDA, a measure of the changes in conductance at the skin surface due to sweat production, is considered a promising alternative for the non-invasive assessment of sympathetic control of the ANS. EDA is sensitive to stress of many kinds. Therefore, as a first step, we tested the sensitivity of EDA, in the time and frequency domains, specifically to cognitive stress during water immersion of the subject (albeit with their measurement finger dry for safety. The data from 14 volunteer subjects were used from the experiment. After a 4-min adjustment and baseline period after being immersed in water, subjects underwent the Stroop task, which is known to induce cognitive stress. The time-domain indices of EDA, skin conductance level (SCL and non-specific skin conductance responses (NS.SCRs, did not change during cognitive stress, compared to baseline measurements. Frequency-domain indices of EDA, EDASymp (based on power spectral analysis and TVSymp (based on time-frequency analysis, did significantly change during cognitive stress. This leads to the conclusion that EDA, assessed by spectral analysis, is sensitive to cognitive stress in water-immersed subjects, and can potentially be used to detect cognitive stress in divers.

  5. Acute stress switches spatial navigation strategy from egocentric to allocentric in a virtual Morris water maze.

    Science.gov (United States)

    van Gerven, Dustin J H; Ferguson, Thomas; Skelton, Ronald W

    2016-07-01

    Stress and stress hormones are known to influence the function of the hippocampus, a brain structure critical for cognitive-map-based, allocentric spatial navigation. The caudate nucleus, a brain structure critical for stimulus-response-based, egocentric navigation, is not as sensitive to stress. Evidence for this comes from rodent studies, which show that acute stress or stress hormones impair allocentric, but not egocentric navigation. However, there have been few studies investigating the effect of acute stress on human spatial navigation, and the results of these have been equivocal. To date, no study has investigated whether acute stress can shift human navigational strategy selection between allocentric and egocentric navigation. The present study investigated this question by exposing participants to an acute psychological stressor (the Paced Auditory Serial Addition Task, PASAT), before testing navigational strategy selection in the Dual-Strategy Maze, a modified virtual Morris water maze. In the Dual-Strategy maze, participants can chose to navigate using a constellation of extra-maze cues (allocentrically) or using a single cue proximal to the goal platform (egocentrically). Surprisingly, PASAT stress biased participants to solve the maze allocentrically significantly more, rather than less, often. These findings have implications for understanding the effects of acute stress on cognitive function in general, and the function of the hippocampus in particular. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. A Three-Dimensional Index for Characterizing Crop Water Stress

    Directory of Open Access Journals (Sweden)

    Jessica A. Torrion

    2014-05-01

    Full Text Available The application of remotely sensed estimates of canopy minus air temperature (Tc-Ta for detecting crop water stress can be limited in semi-arid regions, because of the lack of full ground cover (GC at water-critical crop stages. Thus, soil background may restrict water stress interpretation by thermal remote sensing. For partial GC, the combination of plant canopy temperature and surrounding soil temperature in an image pixel is expressed as surface temperature (Ts. Soil brightness (SB for an image scene varies with surface soil moisture. This study evaluates SB, GC and Ts-Ta and determines a fusion approach to assess crop water stress. The study was conducted (2007 and 2008 on a commercial scale, center pivot irrigated research site in the Texas High Plains. High-resolution aircraft-based imagery (red, near-infrared and thermal was acquired on clear days. The GC and SB were derived using the Perpendicular Vegetation Index approach. The Ts-Ta was derived using an array of ground Ts sensors, thermal imagery and weather station air temperature. The Ts-Ta, GC and SB were fused using the hue, saturation, intensity method, respectively. Results showed that this method can be used to assess water stress in reference to the differential irrigation plots and corresponding yield without the use of additional energy balance calculation for water stress in partial GC conditions.

  7. Co-regulation of water and K(+) transport in sunflower plants during water stress recovery.

    Science.gov (United States)

    Benlloch, Manuel; Benlloch-González, María

    2016-06-01

    16-day-old sunflower (Helianthus annuus L.) plants were subjected to deficit irrigation for 12 days. Following this period, plants were rehydrated for 2 days to study plant responses to post-stress recovery. The moderate water stress treatment applied reduced growth in all plant organs and the accumulation of K(+) in the shoot. After the rehydration period, the stem recovered its growth and reached a similar length to the control, an effect which was not observed in either root or leaves. Moreover, plant rehydration after water stress favored the accumulation of K(+) in the apical zone of the stem and expanding leaves. In the roots of plants under water stress, watering to field capacity, once the plants were de- topped, rapidly favored K(+) and water transport in the excised roots. This quick and short-lived response was not observed in roots of plants recovered from water stress for 2 days. These results suggest that the recovery of plant growth after water stress is related to coordinated water and K(+) transport from the root to the apical zone of the ​​stem and expanding leaves. This stimulation of K(+) transport in the root and its accumulation in the cells of the growing zones of the ​​stem must be one of the first responses induced in the plant during water stress recovery. Copyright © 2016 Elsevier GmbH. All rights reserved.

  8. Rootstock alleviates PEG-induced water stress in grafted pepper seedlings: physiological responses.

    Science.gov (United States)

    Penella, Consuelo; Nebauer, Sergio G; Bautista, Alberto San; López-Galarza, Salvador; Calatayud, Ángeles

    2014-06-15

    Recent studies have shown that tolerance to abiotic stress, including water stress, is improved by grafting. In a previous work, we took advantage of the natural variability of Capsicum spp. and selected accessions tolerant and sensitive to water stress as rootstocks. The behavior of commercial cultivar 'Verset' seedlings grafted onto the selected rootstocks at two levels of water stress provoked by adding 3.5 and 7% PEG (polyethylene glycol) was examined over 14 days. The objective was to identify the physiological traits responsible for the tolerance provided by the rootstock in order to determine if the tolerance is based on the maintenance of the water relations under water stress or through the activation of protective mechanisms. To achieve this goal, various physiological parameters were measured, including: water relations; proline accumulation; gas exchange; chlorophyll fluorescence; nitrate reductase activity; and antioxidant capacity. Our results indicate that the effect of water stress on the measured parameters depends on the duration and intensity of the stress level, as well as the rootstock used. Under control conditions (0% PEG) all plant combinations showed similar values for all measured parameters. In general terms, PEG provoked a strong decrease in the gas exchange parameters in the cultivar grafted onto the sensitive accessions, as also observed in the ungrafted plants. This effect was related to lower relative water content in the plants, provoked by an inefficient osmotic adjustment that was dependent on reduced proline accumulation. At the end of the experiment, chronic photoinhibition was observed in these plants. However, the plants grafted onto the tolerant rootstocks, despite the reduction in photosynthetic rate, maintained the protective capacity of the photosynthetic machinery mediated by osmotic adjustment (based on higher proline content). In addition, water stress limited uptake and further NO3(-) transfer to the leaves. Increased

  9. A water stress index based on water balance modelling for discrimination of grapevine quality and yield

    Directory of Open Access Journals (Sweden)

    Rémi Gaudin

    2014-01-01

    Significance and impact of the study: This water stress index is a valuable tool for explaining the variations in grape yield and quality among various locations and years because it reflects the vineyard water stress history in relation to rainfall regime and soil conditions. Improvement would come from the simulation of FTSW during winter, notably for soils of high Total Transpirable Soil Water. One potential application is the quantification of water stress change brought by irrigation in Mediterranean vineyards, and its relation to grapevine production.

  10. Effect of Model Selection on Computed Water Balance Components

    NARCIS (Netherlands)

    Jhorar, R.K.; Smit, A.A.M.F.R.; Roest, C.W.J.

    2009-01-01

    Soil water flow modelling approaches as used in four selected on-farm water management models, namely CROPWAT. FAIDS, CERES and SWAP, are compared through numerical experiments. The soil water simulation approaches used in the first three models are reformulated to incorporate ail evapotranspiration

  11. Photosynthetic efficiency of Pedunculate oak seedlings under simulated water stress

    Directory of Open Access Journals (Sweden)

    Popović Zorica

    2010-01-01

    Full Text Available Photosynthetic performance of seedlings of Quercus robur exposed to short-term water stress in the laboratory conditions was assessed through the method of induced fluorometry. The substrate for seedlings was clayey loam, with the dominant texture fraction made of silt, followed by clay and fine sand, with total porosity 68.2%. Seedlings were separated in two groups: control (C (soil water regime in pots was maintained at the level of field water capacity and treated (water-stressed, WS (soil water regime was maintained in the range of wilting point and lentocapillary capacity. The photosynthetic efficiency was 0.642±0.25 and 0.522±0.024 (WS and C, respectively, which was mostly due to transplantation disturbances and sporadic leaf chlorosis. During the experiment Fv/Fm decreased in both groups (0.551±0.0100 and 0.427±0.018 in C and WS, respectively. Our results showed significant differences between stressed and control group, in regard to both observed parameters (Fv/Fm and T½. Photosynthetic efficiency of pedunculate oak seedlings was significantly affected by short-term water stress, but to a lesser extent than by sufficient watering.

  12. Identification of water stress genes in Pinus pinaster Ait. by controlled progressive stress and suppression-subtractive hybridization.

    Science.gov (United States)

    Perdiguero, Pedro; Collada, Carmen; Barbero, María Del Carmen; García Casado, Gloria; Cervera, María Teresa; Soto, Alvaro

    2012-01-01

    Climate change is a major challenge particularly for forest tree species, which will have to face the severe alterations of environmental conditions with their current genetic pool. Thus, an understanding of their adaptive responses is of the utmost interest. In this work we have selected Pinus pinaster as a model species. This pine is one of the most important conifers (for which molecular tools and knowledge are far more scarce than for angiosperms) in the Mediterranean Basin, which is characterised in all foreseen scenarios as one of the regions most drastically affected by climate change, mainly because of increasing temperature and, particularly, by increasing drought. We have induced a controlled, increasing water stress by adding PEG to a hydroponic culture. We have generated a subtractive library, with the aim of identifying the genes induced by this stress and have searched for the most reliable expressional candidate genes, based on their overexpression during water stress, as revealed by microarray analysis and confirmed by RT-PCR. We have selected a set of 67 candidate genes belonging to different functional groups that will be useful molecular tools for further studies on drought stress responses, adaptation, and population genomics in conifers, as well as in breeding programs. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  13. Biologically inspired water purification through selective transport

    International Nuclear Information System (INIS)

    Freeman, E C; Soncini, R M; Weiland, L M

    2013-01-01

    Biologically inspired systems based on cellular mechanics demonstrate the ability to selectively transport ions across a bilayer membrane. These systems may be observed in nature in plant roots, which remove select nutrients from the surrounding soil against significant concentration gradients. Using biomimetic principles in the design of tailored active materials allows for the development of selective membranes for capturing and filtering targeted ions. Combining this biomimetic transport system with a method for reclaiming the captured ions will allow for increased removal potential. To illustrate this concept, a device for removing nutrients from waterways to aid in reducing eutrophication is outlined and discussed. Presented is a feasibility study of various cellular configurations designed for this purpose, focusing on maximizing nutrient uptake. The results enable a better understanding of the benefits and obstacles when developing these cellularly inspired systems. (paper)

  14. Alleviation of Water Stress Effects on MR220 Rice by Application of Periodical Water Stress and Potassium Fertilization

    Directory of Open Access Journals (Sweden)

    Nurul Amalina Mohd Zain

    2014-02-01

    Full Text Available The use of periodical water stress and potassium fertilization may enhance rice tolerance to drought stress and improve the crop’s instantaneous water use efficiency without much yield reduction. This study was conducted to assess the effects of different periodical water stress combined with potassium fertilization regimes on growth, yield, leaf gas exchanges and biochemical changes in rice grown in pots and compare them with standard local rice grower practices. Five treatments including (1 standard local grower’s practice (control, 80CF = 80 kg K2O/ha + control flooding; (2 120PW15 = 120 kg K2O/ha + periodical water stress for 15 days; (3 120DS15V = 120 kg K2O/ha + drought stress for 15 days during the vegetative stage; (4 120DS25V = 120 kg K2O/ha + drought stress for 25 days and (5 120DS15R = 120 kg K2O/ha + drought stress for 15 days during the reproductive stage, were evaluated in this experiment. Control and 120PW15 treatments were stopped at 100 DAS, and continuously saturated conditions were applied until harvest. It was found that rice under 120PW15 treatment showed tolerance to drought stress evidenced by increased water use efficiency, peroxidase (POX, catalase (CAT and proline levels, maximum efficiency of photosystem II (fv/fm and lower minimal fluorescence (fo, compared to other treatments. Path coefficient analysis revealed that most of parameters contribute directly rather than indirectly to rice yield. In this experiment, there were four factors that are directly involved with rice yield: grain soluble sugar, photosynthesis, water use efficiency and total chlorophyll content. The residual factors affecting rice yield are observed to be quite low in the experiment (0.350, confirming that rice yield was mostly influenced by the parameters measured during the study.

  15. NMR imaging of water uptake in multilayer polymeric films : stressing the role of mechanical stress

    NARCIS (Netherlands)

    Baukh, V.; Huinink, H.P.; Adan, O.C.G.; Erich, S.J.F.; Ven, van der L.G.J.

    2010-01-01

    The penetration of water into two-layer polymeric films of a hydrophilic base layer and hydrophobic top layer plays an important role in their performance. Little is known about the coupled effects of water uptake and stress in such films. To study such interactive phenomena, time-dependent

  16. Will climate change exacerbate water stress in Central Asia?

    DEFF Research Database (Denmark)

    Siegfried, Tobias; Bernauer, Thomas; Guiennet, Renaud

    2012-01-01

    the Soviet Union collapsed. Will climate change exacerbate water stress and thus conflicts? We have developed a coupled climate, land-ice and rainfall-runoff model for the Syr Darya to quantify impacts and show that climatic changes are likely to have consequences on runoff seasonality due to earlier snow......-melt. This will increase water stress in unregulated catchments because less water will be available for irrigation in the summer months. Threats from geohazards, above all glacier lake outbursts, are likely to increase as well. The area at highest risk is the densely populated, agriculturally productive, and politically......Millions of people in the geopolitically important region of Central Asia depend on water from snow- and glacier-melt driven international rivers, most of all the Syr Darya and Amu Darya. The riparian countries of these rivers have experienced recurring water allocation conflicts ever since...

  17. Identification of genes involved in a water stress response in timothy and mapping of orthologous loci in perennial ryegrass

    DEFF Research Database (Denmark)

    Jonavičienė, Kristina; Studer, Bruno; Asp, Torben

    2012-01-01

    In order to characterize the response of selected grasses to water stress, relative water content (RWC) in leaves and quantum efficiency of photosystem 2 (Fv/Fm) were measured in Phleum pratense L., P. bertolonii DC. and P. phleoides H. Karst. during 6 d of water stress. The results indicated...... differential responses to water stress among the three Phleum species with higher water deficit sensitivity of P. pratense and P. bertolonii than that of P. phleoides. The cDNA-amplified fragment length polymorphism (cDNA-AFLP) technique was applied to identify differentially expressed genes responding...... to water stress in P. pratense. Cloned and sequenced differentially expressed fragments (DEFs) were used for primer design in order to identify orthologous genes in Lolium perenne L. Twelve genes orthologous to P. pratense DEFs were mapped in the L. perenne mapping population VrnA based on a high...

  18. Chlorine stress mediates microbial surface attachment in drinking water systems.

    Science.gov (United States)

    Liu, Li; Le, Yang; Jin, Juliang; Zhou, Yuliang; Chen, Guowei

    2015-03-01

    Microbial attachment to drinking water pipe surfaces facilitates pathogen survival and deteriorates disinfection performance, directly threatening the safety of drinking water. Notwithstanding that the formation of biofilm has been studied for decades, the underlying mechanisms for the origins of microbial surface attachment in biofilm development in drinking water pipelines remain largely elusive. We combined experimental and mathematical methods to investigate the role of environmental stress-mediated cell motility on microbial surface attachment in chlorination-stressed drinking water distribution systems. Results show that at low levels of disinfectant (0.0-1.0 mg/L), the presence of chlorine promotes initiation of microbial surface attachment, while higher amounts of disinfectant (>1.0 mg/L) inhibit microbial attachment. The proposed mathematical model further demonstrates that chlorination stress (0.0-5.0 mg/L)-mediated microbial cell motility regulates the frequency of cell-wall collision and thereby controls initial microbial surface attachment. The results reveal that transport processes and decay patterns of chlorine in drinking water pipelines regulate microbial cell motility and, thus, control initial surface cell attachment. It provides a mechanistic understanding of microbial attachment shaped by environmental disinfection stress and leads to new insights into microbial safety protocols in water distribution systems.

  19. Effect of water impurities on stress corrosion cracking in a boiling water reactor

    International Nuclear Information System (INIS)

    Ljungbery, L.G.; Cubicciotti, D

    1985-01-01

    A series of stress corrosion tests, including corrosion potential and water chemistry measurements, has been performed in the Swedish Ringhals-1 boiling water reactor. Tests have been run under reactor start-up and reactor power operation with normal reactor water conditions and with alternate water chemistry in which hydrogen is added to the feedwater to suppress stress corrosion cracking. During one alternate water chemistry test, there was significant intergranular corrosion cracking of sensitized stainless specimens. It is shown that nitrate and sulfate, arising from an accidental resin intrusion, are likely causes. Nitrate increases the oxidizing power of the water, and sulfate enhances cracking under oxidizing conditions. During another test under start-up conditions, enhanced transgranular stress corrosion cracking in low alloy steels and possibly initiation of cracking in a nickel base alloy was observed as a result of resin intrusion into the reactor water. The intrusion produced acid and sulfate, which are believed to enhance hydrogen cracking conditions

  20. Airborne thermography for crop water stress assessment

    Science.gov (United States)

    Millard, J. P.; Idso, S. B.; Reginato, R. J.; Jackson, R. D.; Ehrler, W. L.; Goettelman, R. C.

    1977-01-01

    Aircraft overflights to obtain canopy temperatures of six differentially irrigated plots of durum wheat were made at Phoenix, Arizona on 1 and 29 April 1976. The data were acquired by a Texas Instruments model RS-25 infrared line scanner operating in the 8 to 14 micrometer bandpass region. Concurrently, plant water tension was measured on the ground with the Scholander pressure bomb technique. The results indicated that canopy temperatures acquired by aircraft about an hour and a half past solar noon correlated well with presunrise plant water tension - a parameter directly related to plant growth and development. The aircraft data also showed significant within-field canopy temperature variability, indicating the superiority of the synoptic view provided by aircraft over the more spotty view obtained by ground-operated infrared thermometers.

  1. Dextran's effects on stressed lenses: water, electrolyte, and radioisotope studies

    International Nuclear Information System (INIS)

    Sanders, D.R.; Bokosky, J.; Peyman, G.A.; Gray, D.

    1979-01-01

    To evaluate the beneficial effects of dextran 40 as an additive to infusion solutions, we studied an experimental model of lens stress with use of buffered, low calcium (Ca ++ )-containing solutions. Incubation in low Ca ++ solutions (pCa = 10.7) for ten hours (stress period) resulted in lens swelling and electrolyte imbalances that were irreversible even with reincubation in physiologic, normal Ca ++ -containing media (pCa = 2.7) (recovery period). The addition of 6% or more of dextran to the media inhibited lens water gain during the stress period. It also rendered the resultant electrolyte imbalances reversible during the recovery period, thus exerting a protective effect. Radioisotope-tracer studies showed that dextran improved the ability of the lens to accumulate rubidium chloride Rb 86 and reduced its efflux during both the stress and recovery periods. Dextran did not markedly decrease sodium chloride Na 22 uptake by lenses under stress

  2. Effects of selected factors on state of stress around a filtration column

    Energy Technology Data Exchange (ETDEWEB)

    Paluch, W.

    1976-01-01

    Operation of mine draining wells is discussed in brown coal surface mining. Methods for well drilling, installation of water draining pipes and design of filters are discussed. Site selection for draining wells is evaluated. Four stages of draining well operation are analyzed. During borehole drilling there is equilibrium between the water in rock strata and the drilling fluid. When a pipe system is lowered into a borehole (2nd phase) loads acting on the pipes are caused by hydrostatic water pressure and pressure of gravel layers. In the 3rd phase of well operation, water pressure causes gravel compaction around the drilling pipe. Pressure on the pipes and its filter system increases. In the 4th phase, well activation initially causes water pressure increase. After the well has reduced the level of hydrostatic pressure, water pressure on the well declines. Water pressure effects on stresses around draining wells are analyzed. Most hazards associated with draining well operation occur during the 4th phase. 4 refs.

  3. Individual treatment selection for patients with posttraumatic stress disorder.

    Science.gov (United States)

    Deisenhofer, Anne-Katharina; Delgadillo, Jaime; Rubel, Julian A; Böhnke, Jan R; Zimmermann, Dirk; Schwartz, Brian; Lutz, Wolfgang

    2018-04-16

    Trauma-focused cognitive behavioral therapy (Tf-CBT) and eye movement desensitization and reprocessing (EMDR) are two highly effective treatment options for posttraumatic stress disorder (PTSD). Yet, on an individual level, PTSD patients vary substantially in treatment response. The aim of the paper is to test the application of a treatment selection method based on a personalized advantage index (PAI). The study used clinical data for patients accessing treatment for PTSD in a primary care mental health service in the north of England. PTSD patients received either EMDR (N = 75) or Tf-CBT (N = 242). The Patient Health Questionnaire (PHQ-9) was used as an outcome measure for depressive symptoms associated with PTSD. Variables predicting differential treatment response were identified using an automated variable selection approach (genetic algorithm) and afterwards included in regression models, allowing the calculation of each patient's PAI. Age, employment status, gender, and functional impairment were identified as relevant variables for Tf-CBT. For EMDR, baseline depressive symptoms as well as prescribed antidepressant medication were selected as predictor variables. Fifty-six percent of the patients (n = 125) had a PAI equal or higher than one standard deviation. From those patients, 62 (50%) did not receive their model-predicted treatment and could have benefited from a treatment assignment based on the PAI. Using a PAI-based algorithm has the potential to improve clinical decision making and to enhance individual patient outcomes, although further replication is necessary before such an approach can be implemented in prospective studies. © 2018 Wiley Periodicals, Inc.

  4. Contrasting extremes in water-related stresses determine species survival

    Science.gov (United States)

    Bartholomeus, R. P.; Witte, J. P. M.; van Bodegom, P. M.; van Dam, J. C.; Aerts, R.

    2012-04-01

    In temperate climates, soil moisture, in concert with nutrient availability and soil acidity, is the most important environmental filter in determining local plant species composition, as it determines the availability of both oxygen and water to plant roots. These resources are indispensable for meeting the physiological demands of plants. Especially the occurrence of both excessive dry and wet moisture conditions at a particular site has strong implications for the survival of species, because plants need traits that allow them to respond to such counteracting conditions. However, adapting to one stress may go at the cost of the other, i.e. there exists a trade-off in the tolerance for wet conditions and the tolerance for dry conditions. Until now, both large-scale (global) and plot-scale effects of soil moisture conditions on plant species composition have mostly been investigated through indirect environmental measures, which do not include the key soil physical and plant physiological processes in the soil-plant-atmosphere system. Moreover, researchers only determined effects of one of the water-related stresses, i.e. either oxygen or drought stress. In order to quantify both oxygen and drought stress with causal measures, we focused on interacting meteorological, soil physical, microbial, and plant physiological processes in the soil-plant-atmosphere system. We simulated these plant stresses with a novel, process-based approach, incorporating in detail the interacting processes in the soil-plant-atmosphere interface. High variability and extremes in resource availability can be highly detrimental to plant species ('you can only die once'). We show that co-occurrence of oxygen and drought stress reduces the percentage of specialists within a vegetation plot. The percentage of non-specialists within a vegetation plot, however, decreases significantly with increasing stress as long as only one of the stresses prevails, but increases significantly with an

  5. Optimization of Water Allocation between Different Crops in Water Stress Conditions in Qazvin Irrigation Network

    Directory of Open Access Journals (Sweden)

    Mehdi Mohammad khani

    2017-06-01

    minimum productivity index. Therefore, in water deficit conditions, the priority of water distribution in all options is for tomatoes and the last priority for sugar beets. In all of the options, wheat, barley and canola ascend in productivity index and corn and sugar beets descend in productivity index. Conclusion: Studying water- production index shows that considering instructions will result in optimal productivity that in turn will increase production and network total income. Optimal model results show that drought effects can be satisfied with optimal and targeted management in allocating water, so that network total income has not reduced in stress occurrences compared to network net income. Optimization method in model development has been selected according to aim of model and it is proposed that model results to be assessed by non- linear optimization methods. It is proposed that, different scenarios of climate are studied in region according to climate changes and optimal allocation of water is prepared according to the effect of these scenarios on temperature increase, raining decrease and products water need increase in present cultivation method. For model efficiency increase, it is proposed that using neural networks capabilities, intelligent prediction of the input discharge to the network is done and the possibility of comprehensive management and timely combining of network with water allocation optimal model is provided.

  6. Optimal water meter selection system | Johnson | Water SA

    African Journals Online (AJOL)

    Economic/financial analysis based on an income statement together with capital budgeting techniques assist with the determination of the financial suitability of investing in a new replacement water meter. This financial analysis includes various potential income and expenditure components that will result from the ...

  7. Influence of water stress on Botryosphaeriaceae disease expression in grapevines

    Directory of Open Access Journals (Sweden)

    Jan VAN NIEKERK

    2011-12-01

    Full Text Available Several species in Botryosphaeriaceae have been associated with grapevine trunk diseases. To evaluate the effect of water stress on infection of grapevines by Botryosphaeriaceae spp., 1-year-old Shiraz/101-14 Mgt nursery grapevine plants were planted in plastic potting bags and placed outdoors under shade netting. Five weeks after planting, vines were pruned and the pruning wounds inoculated with spore suspensions of Neofusicoccum australe, Neofusicoccum parvum, Lasiodiplodia theobromae or Diplodia seriata. Control treatments consisted of applications of sterile water or a Trichoderma harzianum spore suspension. Stem inoculations were done by inserting a colonised or uncolonised agar plug into a wound made in each stem. Four different irrigation regimes were introduced 12 weeks after planting to simulate varying degrees of water stress. Measurements of stomatal conductance, photosynthetic rate and leaf spectrometry were made to monitor physiological stress. Eight months after inoculation, vines were uprooted and the root, shoot and plant mass of each vine determined. Lesions observed in the inoculated pruning wounds and stems were also measured. Vines subjected to the lowest irrigation regime were significantly smaller than optimally irrigated vines. Water stressed vines also had significantly lower photosynthetic rates and levels of stomatal conductance compared with vines receiving optimal irrigation, indicating that these plants experienced significantly higher levels of physiological stress. The mean lesion length was significantly longer in the pruning wounds and stems of plants subjected to the lowest irrigation regime, with lesion length declining linearly with increasing irrigation volume. These results clearly indicate that when a grapevine is exposed to water stress, colonisation and disease expression by Botryosphaeriaceae spp. are much more severe.

  8. Cryosphere, climate and capitalism: drivers of Central Asian water stress

    Science.gov (United States)

    Hill, A. F.; Minbaeva, C.; Wilson, A. M.; Satylkanov, R.; Armstrong, R. L.

    2017-12-01

    The importance of meltwater to Central Asia's trans-boundary rivers and groundwater reserves suggests future water stress for the region. Climate is likely to induce shifts in water supply volume and delivery timing, while a complex fabric of socio-political factors complicates water management and adaptation strategies. To clarify the drivers of water stress over a large scale (440km, 4,200m elevation change), we conducted a socio-hydrologic study of Krygyzstan's Naryn River in the Tien Shan mountains, headwater stem of the Syr Darya and source of the disappearing Aral Sea. Using a combination of geochemical sampling, hydro-chemical mixing models, remote sensing image processing and community surveys, we characterized both the social and hydrologic controls of water supplies from glacier snout to downstream areas where people, hydropower and agriculture utilize water. We find melt-sourced water dominates hydrologic inputs to both surface flow and groundwater from headwaters to reservoir, suggesting high sensitivity of water supply to a warming climate. On a regional scale, the importance of melt to trans-boundary river flow serving thirsty downstream countries may increase hostility between already tense neighbors. Water stress on the basin level, however, is currently less impacted by supply than by access, agricultural knowledge deficiencies and infrastructure issues that are relic from the post-Soviet transition in the 1990s. The interplay of these factors suggests the need for creative and proactive water management adaptation planning in the Naryn basin and throughout similar melt-reliant areas of arid Central Asia.

  9. Comparison of the protective effects of seven selected herbs against oxidative stress

    Directory of Open Access Journals (Sweden)

    Lee-Wen Chang

    2015-07-01

    Full Text Available Objective: To compare the protective effects of the water extracts of seven herbs, including Solanum indicum L., Mallotus repandus (Wild Muell-Arg. (MRM, Bombax malabarica DC (BMDC, Tadehagi triquetrum (L. Ohashi (TTLO, Clinacanthus nutans (Burm f. Lindau, Salvia plebeia R. Br (SPRB, Ixeris chinensis Mak (ICM, against tert-butylhydroperoxide (t-BHP-induced oxidative stress in Clone 9 cells. Methods: To evaluate the antioxidant properties of water extracts from seven herbs, reducing ability, metal-chelating activity and radical-scavenging activity such as 2,2′-azino-bis(3- ethylbenzothiazoline-6-sulphonic acid radical cation and 1,1-diphenyl-2-picrylhydrazyl (DPPH were determined. In cellular systems, t-BHP was used as a model oxidant to induce oxidative stress. 2′,7′-Dichlorofluorescin diacetate and chloromethylfluorescein-diacetate were used as fluorescence probe to determine reactive oxygen species generation and glutathione level in t-BHP-induced Clone 9 cells, respectively. In addition, total tannins, total anthocyanins, total polyphenolics and flavonoids were determined. Results: According to the data obtained from the trolox equivalent antioxidant capacity method, DPPH radical scavenging assay and reducing ability determination, MRM, SPRB, and BMDC showed relatively high antioxidant properties while TTLO and ICM were in the middle and Solanum indicum and Clinacanthus nutans had relatively low activity. In cellular model systems, SPRB, BMDC, and TTLO showed higher protective effects against t-BHP-induced oxidative stress. BMDC, ICM, and TTLO displayed higher inhibitory effects on reactive oxygen species generation in t-BHP-induced Clone 9 cells. In addition, SPRB, MRM, and BMDC showed significantly positive modulated glutathione levels. Tannins, anthocyanins, flavonoids and polyphenolics were present in the herbs, which may in part contribute to regulating the oxidative stress. Conclusions: These results indicated that the seven

  10. Economics of selected water control technologies and their ...

    African Journals Online (AJOL)

    Using a production function, marginal productivity of farm inputs and benefit-cost analysis, we explore the economics of selected water control technologies. From the production function, all farm inputs, including irrigation water is found to have a significant and positive effect on yield. Marginal value products of farm inputs ...

  11. Selective copper catalysed aromatic N-arylation in water

    DEFF Research Database (Denmark)

    Engel-Andreasen, Jens; Shimpukade, Bharat; Ulven, Trond.

    2013-01-01

    4,7-Dipyrrolidinyl-1,10-phenanthroline (DPPhen) was identified as an efficient ligand for copper catalyzed selective arom. N-arylation in water. N-Arylation of indoles, imidazoles and purines proceeds with moderate to excellent yields and complete selectivity over aliph. amines. Aq. medium...

  12. Potability Evaluation of Selected River Waters in Ebonyi State, Nigeria

    African Journals Online (AJOL)

    The study focused on the seasonal variation of physiochemical and microbial characteristics of three selected river water in Ebonyi State for human consumption. The three selected rivers studied were Iyioka, Idima and Ubei Rivers. Data were generated using Direct Reading Engineering method (DREM), Gravimetric ...

  13. The Impact of Water Shortages on Educational Delivery in Selected ...

    African Journals Online (AJOL)

    The goal of the study was to investigate the impact of water shortages on educational delivery in selected schools in Harare East District. The population included school heads, teachers and pupils all drawn from selected schools of Harare East District. The sample consisted of five school heads, fifty teachers and one ...

  14. Water and carbon dynamics in selected ecosystems in China

    Science.gov (United States)

    Ge Sun; J. Sun; G. Zhou

    2009-01-01

    Global climate change and unprecedented socioeconomic evelopment have resulted in tremendous environmental, ecological and resource stress on China’s continued growth.Among the numerous challenges, nothing is more pressing than ecosystem degradation as evidenced by the regional-scale air and water pollution, groundwater...

  15. Water stress in global transboundary river basins : Significance of upstream water use on downstream stress

    NARCIS (Netherlands)

    Munia, H.; Guillaume, J. H A; Mirumachi, N.; Porkka, M.; Wada, Y.|info:eu-repo/dai/nl/341387819; Kummu, M.

    2016-01-01

    Growing population and water demand have increased pressure on water resources in various parts of the globe, including many transboundary river basins. While the impacts of upstream water use on downstream water availability have been analysed in many of these international river basins, this has

  16. Assessing maize foliar water stress levels under field conditions ...

    African Journals Online (AJOL)

    The management of spectral reflectance data to extract information of importance for plant water status has been motivated by knowledge of the availability of specific bands in the electromagnetic spectrum responsible for water absorption. The purpose of this study was to investigate the potential of using selected spectral ...

  17. Water stress induced changes in antioxidant enzymes, membrane ...

    African Journals Online (AJOL)

    Water stress induced changes in antioxidant enzymes membrane stablity index and seed protein profiling of four different wheat (Triticum aestivum L.) accessions (011251, 011417, 011320 and 011393) were determined in a pot study under natural condition during the wheat-growing season 2005 and 2006. Sampling was ...

  18. Biomass production and potential water stress increase with ...

    African Journals Online (AJOL)

    The choice of planting density and tree genotype are basic decisions when establishing a forest stand. Understanding the interaction between planting density and genotype, and their relationship with biomass production and potential water stress, is crucial as forest managers are faced with a changing climate. However ...

  19. Water stress strengthens mutualism among ants, trees, and scale insects.

    Directory of Open Access Journals (Sweden)

    Elizabeth G Pringle

    2013-11-01

    Full Text Available Abiotic environmental variables strongly affect the outcomes of species interactions. For example, mutualistic interactions between species are often stronger when resources are limited. The effect might be indirect: water stress on plants can lead to carbon stress, which could alter carbon-mediated plant mutualisms. In mutualistic ant-plant symbioses, plants host ant colonies that defend them against herbivores. Here we show that the partners' investments in a widespread ant-plant symbiosis increase with water stress across 26 sites along a Mesoamerican precipitation gradient. At lower precipitation levels, Cordia alliodora trees invest more carbon in Azteca ants via phloem-feeding scale insects that provide the ants with sugars, and the ants provide better defense of the carbon-producing leaves. Under water stress, the trees have smaller carbon pools. A model of the carbon trade-offs for the mutualistic partners shows that the observed strategies can arise from the carbon costs of rare but extreme events of herbivory in the rainy season. Thus, water limitation, together with the risk of herbivory, increases the strength of a carbon-based mutualism.

  20. Water Stress Strengthens Mutualism Among Ants, Trees, and Scale Insects

    Science.gov (United States)

    Pringle, Elizabeth G.; Akçay, Erol; Raab, Ted K.; Dirzo, Rodolfo; Gordon, Deborah M.

    2013-01-01

    Abiotic environmental variables strongly affect the outcomes of species interactions. For example, mutualistic interactions between species are often stronger when resources are limited. The effect might be indirect: water stress on plants can lead to carbon stress, which could alter carbon-mediated plant mutualisms. In mutualistic ant–plant symbioses, plants host ant colonies that defend them against herbivores. Here we show that the partners' investments in a widespread ant–plant symbiosis increase with water stress across 26 sites along a Mesoamerican precipitation gradient. At lower precipitation levels, Cordia alliodora trees invest more carbon in Azteca ants via phloem-feeding scale insects that provide the ants with sugars, and the ants provide better defense of the carbon-producing leaves. Under water stress, the trees have smaller carbon pools. A model of the carbon trade-offs for the mutualistic partners shows that the observed strategies can arise from the carbon costs of rare but extreme events of herbivory in the rainy season. Thus, water limitation, together with the risk of herbivory, increases the strength of a carbon-based mutualism. PMID:24223521

  1. Water stress strengthens mutualism among ants, trees, and scale insects.

    Science.gov (United States)

    Pringle, Elizabeth G; Akçay, Erol; Raab, Ted K; Dirzo, Rodolfo; Gordon, Deborah M

    2013-11-01

    Abiotic environmental variables strongly affect the outcomes of species interactions. For example, mutualistic interactions between species are often stronger when resources are limited. The effect might be indirect: water stress on plants can lead to carbon stress, which could alter carbon-mediated plant mutualisms. In mutualistic ant-plant symbioses, plants host ant colonies that defend them against herbivores. Here we show that the partners' investments in a widespread ant-plant symbiosis increase with water stress across 26 sites along a Mesoamerican precipitation gradient. At lower precipitation levels, Cordia alliodora trees invest more carbon in Azteca ants via phloem-feeding scale insects that provide the ants with sugars, and the ants provide better defense of the carbon-producing leaves. Under water stress, the trees have smaller carbon pools. A model of the carbon trade-offs for the mutualistic partners shows that the observed strategies can arise from the carbon costs of rare but extreme events of herbivory in the rainy season. Thus, water limitation, together with the risk of herbivory, increases the strength of a carbon-based mutualism.

  2. Potential Study of Water Extraction from Selected Plants

    Directory of Open Access Journals (Sweden)

    Musa S.

    2017-01-01

    Full Text Available Water is absorbed by the roots of a plant and transported subsequently as a liquid to all parts of the plant before being released into the atmosphere as transpiration. In this study, seven(7selected plant species collected from urban, rural and forested areas were studied and characterized. The water was collected using transparent plastic bag that being tied to the tree branches. Then, the vapouris water trapped inside the plastic bag and through the condensation process, it become water droplets. Water quality parameters such as temperature, pH value, DO, turbidity, colour, magnesium, calcium, nitrate and chloride were analyzed. The analysis was compared to drinking water quality standard set by the Ministry of Health Malaysia. Based on the results, it shows that banana leaf has a higher rate of water extraction compared to others. Thus, the plant can be categorised as a helpful guide for emergency use of water or as an alternative source to survival.

  3. Water Stress Scatters Nitrogen Dilution Curves in Wheat

    Directory of Open Access Journals (Sweden)

    Marianne Hoogmoed

    2018-04-01

    Full Text Available Nitrogen dilution curves relate a crop’s critical nitrogen concentration (%Nc to biomass (W according to the allometric model %Nc = a W-b. This model has a strong theoretical foundation, and parameters a and b show little variation for well-watered crops. Here we explore the robustness of this model for water stressed crops. We established experiments to examine the combined effects of water stress, phenology, partitioning of biomass, and water-soluble carbohydrates (WSC, as driven by environment and variety, on the %Nc of wheat crops. We compared models where %Nc was plotted against biomass, growth stage and thermal time. The models were similarly scattered. Residuals of the %Nc - biomass model at anthesis were positively related to biomass, stem:biomass ratio, Δ13C and water supply, and negatively related to ear:biomass ratio and concentration of WSC. These are physiologically meaningful associations explaining the scatter of biomass-based dilution curves. Residuals of the thermal time model showed less consistent associations with these variables. The biomass dilution model developed for well-watered crops overestimates nitrogen deficiency of water-stressed crops, and a biomass-based model is conceptually more justified than developmental models. This has implications for diagnostic and modeling. As theory is lagging, a greater degree of empiricism might be useful to capture environmental, chiefly water, and genotype-dependent traits in the determination of critical nitrogen for diagnostic purposes. Sensitivity analysis would help to decide if scaling nitrogen dilution curves for crop water status, and genotype-dependent parameters are needed.

  4. Selective Electrochemical Generation of Hydrogen Peroxide from Water Oxidation

    DEFF Research Database (Denmark)

    Viswanathan, Venkatasubramanian; Hansen, Heine Anton; Nørskov, Jens K.

    2015-01-01

    evolution and form hydrogen peroxide. Using density functional theory calculations, we show that the free energy of adsorbed OH* can be used to determine selectivity trends between the 2e(-) water oxidation to H2O2 and the 4e(-) oxidation to O2. We show that materials which bind oxygen intermediates...... sufficiently weakly, such as SnO2, can activate hydrogen peroxide evolution. We present a rational design principle for the selectivity in electrochemical water oxidation and identify new material candidates that could perform H2O2 evolution selectively....

  5. Daytime soybean transcriptome fluctuations during water deficit stress.

    Science.gov (United States)

    Rodrigues, Fabiana Aparecida; Fuganti-Pagliarini, Renata; Marcolino-Gomes, Juliana; Nakayama, Thiago Jonas; Molinari, Hugo Bruno Correa; Lobo, Francisco Pereira; Harmon, Frank G; Nepomuceno, Alexandre Lima

    2015-07-07

    Since drought can seriously affect plant growth and development and little is known about how the oscillations of gene expression during the drought stress-acclimation response in soybean is affected, we applied Illumina technology to sequence 36 cDNA libraries synthesized from control and drought-stressed soybean plants to verify the dynamic changes in gene expression during a 24-h time course. Cycling variables were measured from the expression data to determine the putative circadian rhythm regulation of gene expression. We identified 4866 genes differentially expressed in soybean plants in response to water deficit. Of these genes, 3715 were differentially expressed during the light period, from which approximately 9.55% were observed in both light and darkness. We found 887 genes that were either up- or down-regulated in different periods of the day. Of 54,175 predicted soybean genes, 35.52% exhibited expression oscillations in a 24 h period. This number increased to 39.23% when plants were submitted to water deficit. Major differences in gene expression were observed in the control plants from late day (ZT16) until predawn (ZT20) periods, indicating that gene expression oscillates during the course of 24 h in normal development. Under water deficit, dissimilarity increased in all time-periods, indicating that the applied stress influenced gene expression. Such differences in plants under stress were primarily observed in ZT0 (early morning) to ZT8 (late day) and also from ZT4 to ZT12. Stress-related pathways were triggered in response to water deficit primarily during midday, when more genes were up-regulated compared to early morning. Additionally, genes known to be involved in secondary metabolism and hormone signaling were also expressed in the dark period. Gene expression networks can be dynamically shaped to acclimate plant metabolism under environmental stressful conditions. We have identified putative cycling genes that are expressed in soybean leaves

  6. Constant load and constant displacement stress corrosion in simulated water reactor environments

    International Nuclear Information System (INIS)

    Lloyd, G.J.

    1987-02-01

    The stress corrosion behaviour of selected water reactor constructional materials, as determined by constant load or constant displacement test techniques, is reviewed. Experimental results obtained using a very wide range of conditions have been collected in a form for easy reference. A discussion is given of some apparent trends in these data. The possible reasons for these trends are considered together with a discussion of how the observed discrepancies may be resolved. (author)

  7. Phosphatidic acid, a versatile water-stress signal in roots

    Directory of Open Access Journals (Sweden)

    Fionn eMcLoughlin

    2013-12-01

    Full Text Available Adequate water supply is of utmost importance for growth and reproduction of plants. In order to cope with water deprivation, plants have to adapt their development and metabolism to ensure survival. To maximize water use efficiency, plants use a large array of signaling mediators such as hormones, protein kinases and phosphatases, Ca2+, reactive oxygen species and low abundant phospholipids that together form complex signaling cascades. Phosphatidic acid (PA is a signaling lipid that rapidly accumulates in response to a wide array of abiotic stress stimuli. PA formation provides the cell with spatial and transient information about the external environment by acting as a protein-docking site in cellular membranes. PA reportedly binds to a number of proteins that play a role during water limiting conditions, such as drought and salinity and has been shown to play an important role in maintaining root system architecture. Members of two osmotic stress-activated protein kinase families, sucrose non-fermenting 1-related protein kinase 2 (SnRK2 and mitogen activated protein kinases (MAPKs were recently shown bind PA and are also involved in the maintenance of root system architecture and salinity stress tolerance. In addition, PA regulates several proteins involved in abscisic acid (ABA-signaling. PA-dependent recruitment of glyceraldehyde-3-phosphate dehydrogenase (GAPDH under water limiting conditions indicates a role in regulating metabolic processes. Finally, a recent study also shows the PA recruits the clathrin heavy chain and a potassium channel subunit, hinting towards additional roles in cellular trafficking and potassium homeostasis. Taken together, the rapidly increasing number of proteins reported to interact with PA implies a broad role for this versatile signaling phospholipid in mediating salt and water stress responses.

  8. Metabolomic analysis of the selection response of Drosophila melanogaster to environmental stress

    DEFF Research Database (Denmark)

    Malmendal, Anders; Sørensen, Jesper Givskov; Overgaard, Johannes

    2013-01-01

    -regulated in response to selection for some of the stresses in this study. Overall, the results illustrate that selection markedly alters the metabolite profile and that the coupling between different levels of biological organization indeed is present though not very strong for stress selection at this level......We investigated the global metabolite response to artificial selection for tolerance to stressful conditions such as cold, heat, starvation, and desiccation, and for longevity in Drosophila melanogaster. Our findings were compared to data from other levels of biological organization, including gene...... expression, physiological traits, and organismal stress tolerance phenotype. Overall, we found that selection for environmental stress tolerance changes the metabolomic (1)H NMR fingerprint largely in a similar manner independent of the trait selected for, indicating that experimental evolution led...

  9. The effect of water on thermal stresses in polymer composites

    Science.gov (United States)

    Sullivan, Roy M.

    1994-01-01

    The fundamentals of the thermodynamic theory of mixtures and continuum thermochemistry are reviewed for a mixture of condensed water and polymer. A specific mixture which is mechanically elastic with temperature and water concentration gradients present is considered. An expression for the partial pressure of water in the mixture is obtained based on certain assumptions regarding the thermodynamic state of the water in the mixture. Along with a simple diffusion equation, this partial pressure expression may be used to simulate the thermostructural behavior of polymer composite materials due to water in the free volumes of the polymer. These equations are applied to a specific polymer composite material during isothermal heating conditions. The thermal stresses obtained by the application of the theory are compared to measured results to verify the accuracy of the approach.

  10. Transcriptome Dynamics of Pseudomonas putida KT2440 under Water Stress

    DEFF Research Database (Denmark)

    Gülez, Gamze; Dechesne, Arnaud; Workman, Christopher

    2012-01-01

    Water deprivation can be a major stressor to microbial life in surface and subsurface soil. In unsaturated soils, the matric potential (Ψm) is often the main component of the water potential, which measures the thermodynamic availability of water. A low matric potential usually translates...... into water forming thin liquid films in the soil pores. Little is known of how bacteria respond to such conditions, where, in addition to facing water deprivation that might impair their metabolism, they have to adapt their dispersal strategy as swimming motility may be compromised. Using the pressurized...... porous surface model (PPSM), which allows creation of thin liquid films by controlling Ψm, we examined the transcriptome dynamics of Pseudomonas putida KT2440. We identified the differentially expressed genes in cells exposed to a mild matric stress (–0.4 MPa) for 4, 24, or 72 h. The major response...

  11. Seasonal water storage, stress modulation and California seismicity

    Science.gov (United States)

    Johnson, C. W.; Burgmann, R.; Fu, Y.

    2017-12-01

    Establishing what controls the timing of earthquakes is fundamental to understanding the nature of the earthquake cycle and critical to determining time-dependent earthquake hazard. Seasonal loading provides a natural laboratory to explore the crustal response to a quantifiable transient force. In California, the accumulation of winter snowpack in the Sierra Nevada, surface water in lakes and reservoirs, and groundwater in sedimentary basins follow the annual cycle of wet winters and dry summers. The surface loads resulting from the seasonal changes in water storage produce elastic deformation of the Earth's crust. We used 9 years of global positioning system (GPS) vertical deformation time series to constrain models of monthly hydrospheric loading and the resulting stress changes on fault planes of small earthquakes. Previous studies posit that temperature, atmospheric pressure, or hydrologic changes may strain the lithosphere and promote additional earthquakes above background levels. Depending on fault geometry, the addition or removal of water increases the Coulomb failure stress. The largest stress amplitudes are occurring on dipping reverse faults in the Coast Ranges and along the eastern Sierra Nevada range front. We analyze 9 years of M≥2.0 earthquakes with known focal mechanisms in northern and central California to resolve fault-normal and fault-shear stresses for the focal geometry. Our results reveal 10% more earthquakes occurring during slip-encouraging fault-shear stress conditions and suggest that earthquake populations are modulated at periods of natural loading cycles, which promote failure by stress changes on the order of 1-5 kPa. We infer that California seismicity rates are modestly modulated by natural hydrological loading cycles.

  12. Compounding Impacts of Human-Induced Water Stress and Climate Change on Water Availability

    Science.gov (United States)

    Mehran, Ali; AghaKouchak, Amir; Nakhjiri, Navid; Stewardson, Michael J.; Peel, Murray C.; Phillips, Thomas J.; Wada, Yoshihide; Ravalico, Jakin K.

    2017-01-01

    The terrestrial phase of the water cycle can be seriously impacted by water management and human water use behavior (e.g., reservoir operation, and irrigation withdrawals). Here we outline a method for assessing water availability in a changing climate, while explicitly considering anthropogenic water demand scenarios and water supply infrastructure designed to cope with climatic extremes. The framework brings a top-down and bottom-up approach to provide localized water assessment based on local water supply infrastructure and projected water demands. When our framework is applied to southeastern Australia we find that, for some combinations of climatic change and water demand, the region could experience water stress similar or worse than the epic Millennium Drought. We show considering only the influence of future climate on water supply, and neglecting future changes in water demand and water storage augmentation might lead to opposing perspectives on future water availability. While human water use can significantly exacerbate climate change impacts on water availability, if managed well, it allows societies to react and adapt to a changing climate. The methodology we present offers a unique avenue for linking climatic and hydrologic processes to water resource supply and demand management and other human interactions.

  13. Moderate water stress affects tomato leaf water relations in dependence on the nitrogen supply

    NARCIS (Netherlands)

    Garcia, A.L.; Marcelis, L.F.M.; Garcia-Sanchez, F.; Nicolas, N.; Martinez, V.

    2007-01-01

    The responses of water relations, stomatal conductance (g(s)) and growth parameters of tomato (Lycopersicon esculentum Mill. cv. Royesta) plants to nitrogen fertilisation and drought were studied. The plants were subjected to a long-term, moderate and progressive water stress by adding 80 % of the

  14. Water stress detection in the Amazon using radar

    Science.gov (United States)

    van Emmerik, Tim; Steele-Dunne, Susan; Paget, Aaron; Oliveira, Rafael S.; Bittencourt, Paulo R. L.; Barros, Fernanda de V.; van de Giesen, Nick

    2017-07-01

    The Amazon rainforest plays an important role in the global water and carbon cycle, and though it is predicted to continue drying in the future, the effect of drought remains uncertain. Developments in remote sensing missions now facilitate large-scale observations. The RapidScat scatterometer (Ku band) mounted on the International Space Station observes the Earth in a non-Sun-synchronous orbit, which allows for studying changes in the diurnal cycle of radar backscatter over the Amazon. Diurnal cycles in backscatter are significantly affected by the state of the canopy, especially during periods of increased water stress. We use RapidScat backscatter time series and water deficit measurements from dendrometers in 20 trees during a 9 month period to relate variations in backscatter to increased tree water deficit. Morning radar bacskcatter dropped significantly with increased tree water deficit measured with dendrometers. This provides unique observational evidence that demonstrates the sensitivity of radar backscatter to vegetation water stress, highlighting the potential of drought detection and monitoring using radar.

  15. Assessment of possibility of primary water stress corrosion cracking occurrence based on residual stress analysis in pressurizer safety nozzle of nuclear power plant

    International Nuclear Information System (INIS)

    Lee, Kyoung Soo; Kim, W.; Lee, Jeong Geun

    2012-01-01

    Primary water stress corrosion cracking (PWSCC) is a major safety concern in the nuclear power industry worldwide. PWSCC is known to initiate only in the condition in which sufficiently high tensile stress is applied to alloy 600 tube material or alloy 82/182 weld material in pressurized water reactor operating environments. However, it is still uncertain how much tensile stress is required to generate PWSCC or what causes such high tensile stress. This study was performed to predict the magnitude of weld residual stress and operating stress and compare it with previous experimental results for PWSCC initiation. For the study, a pressurizer safety nozzle was selected because it is reported to be vulnerable to PWSCC in overseas plants. The assessment was conducted by numerical analysis. Before performing stress analysis for plant conditions, a preliminary mock-up analysis was done. The result of the preliminary analysis was validated by residual stress measurement in the mockup. After verification of the analysis methodology, an analysis under plant conditions was conducted. The analysis results show that the stress level is not high enough to initiate PWSCC. If a plant is properly welded and operated, PWSCC is not likely to occur in the pressurizer safety nozzle.

  16. Selection Criteria for Water Disinfection Techniques in Agricultural Practices

    OpenAIRE

    Haute, Sam van; Sampers, Imca; Jacxsens, Liesbeth; Uyttendaele, Mieke

    2013-01-01

    This paper comprises a selection tool for water disinfection methods for fresh produce pre- and postharvest practices. A variety of water disinfection technologies is available on the market and no single technology is the best choice for all applications. It can be difficult for end users to choose the technology that is best fit for a specific application. Therefore, the different technologies were characterized in order to identify criteria that influence the suitability of a technology fo...

  17. Stress Coefficients for Soil Water Balance Combined with Water Stress Indicators for Irrigation Scheduling of Woody Crops

    Directory of Open Access Journals (Sweden)

    Maria Isabel Ferreira

    2017-06-01

    Full Text Available There are several causes for the failure of empirical models to estimate soil water depletion and to calculate irrigation depths, and the problem is particularly critical in tall, uneven, deficit irrigated (DI crops in Mediterranean climates. Locally measured indicators that quantify water status are useful for addressing those causes and providing feed-back information for improving the adequacy of simple models. Because of their high aerodynamic resistance, the canopy conductance of woody crops is an important factor in determining evapotranspiration (ET, and accurate stress coefficient (Ks values are needed to quantify the impact of stomatal closure on ET. A brief overview of basic general principles for irrigation scheduling is presented with emphasis on DI applications that require Ks modelling. The limitations of existing technology related to scheduling of woody crops are discussed, including the shortcomings of plant-based approaches. In relation to soil water deficit and/or predawn leaf water potential, several woody crop Ks functions are presented in a secondary analysis. Whenever the total and readily available water data were available, a simple Ks model was tested. The ultimate aim of this discussion is to illustrate the central concept: that a combination of simple ET models and water stress indicators is required for scheduling irrigation of deep-rooted woody crops.

  18. Drinking water biofilm cohesiveness changes under chlorination or hydrodynamic stress.

    Science.gov (United States)

    Mathieu, L; Bertrand, I; Abe, Y; Angel, E; Block, J C; Skali-Lami, S; Francius, G

    2014-05-15

    Attempts at removal of drinking water biofilms rely on various preventive and curative strategies such as nutrient reduction in drinking water, disinfection or water flushing, which have demonstrated limited efficiency. The main reason for these failures is the cohesiveness of the biofilm driven by the physico-chemical properties of its exopolymeric matrix (EPS). Effective cleaning procedures should break up the matrix and/or change the elastic properties of bacterial biofilms. The aim of this study was to evaluate the change in the cohesive strength of two-month-old drinking water biofilms under increasing hydrodynamic shear stress τw (from ∼0.2 to ∼10 Pa) and shock chlorination (applied concentration at T0: 10 mg Cl2/L; 60 min contact time). Biofilm erosion (cell loss per unit surface area) and cohesiveness (changes in the detachment shear stress and cluster volumes measured by atomic force microscopy (AFM)) were studied. When rapidly increasing the hydrodynamic constraint, biofilm removal was found to be dependent on a dual process of erosion and coalescence of the biofilm clusters. Indeed, 56% of the biofilm cells were removed with, concomitantly, a decrease in the number of the 50-300 μm(3) clusters and an increase in the number of the smaller (i.e., 600 μm(3)) ones. Moreover, AFM evidenced the strengthening of the biofilm structure along with the doubling of the number of contact points, NC, per cluster volume unit following the hydrodynamic disturbance. This suggests that the compactness of the biofilm exopolymers increases with hydrodynamic stress. Shock chlorination removed cells (-75%) from the biofilm while reducing the volume of biofilm clusters. Oxidation stress resulted in a decrease in the cohesive strength profile of the remaining drinking water biofilms linked to a reduction in the number of contact points within the biofilm network structure in particular for the largest biofilm cluster volumes (>200 μm(3)). Changes in the cohesive

  19. Effects of virtual water flow on regional water resources stress: A case study of grain in China.

    Science.gov (United States)

    Sun, Shikun; Wang, Yubao; Engel, Bernie A; Wu, Pute

    2016-04-15

    Scarcity of water resources is one of the major challenges in the world, particularly for the main water consumer, agriculture. Virtual water flow (VWF) promotes water redistribution geographically and provides a new solution for resolving regional water shortage and improving water use efficiency in the world. Virtual water transfer among regions will have a significant influence on the water systems in both grain export and import regions. In order to assess the impacts of VWF related grain transfer on regional water resources conditions, the study takes mainland China as study area for a comprehensive evaluation of virtual water flow on regional water resources stress. Results show that Northeast China and Huang-Huai-Hai region are the major grain production regions as well as the major virtual water export regions. National water savings related to grain VWF was about 58Gm(3), with 48Gm(3) blue water and 10Gm(3) green water. VWF changes the original water distribution and has a significant effect on water resources in both virtual water import and export regions. Grain VWF significantly increased water stress in grain export regions and alleviated water stress in grain import regions. Water stress index (WSI) of Heilongjiang and Inner Mongolia has been increased by 138% and 129% due to grain export. Stress from water shortages is generally severe in export regions, and issues with the sustainability of grain production and VWF pattern are worthy of further exploration. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Inverse estimation of soil hydraulic properties and water repellency following artificially induced drought stress

    Directory of Open Access Journals (Sweden)

    Filipović Vilim

    2018-06-01

    Full Text Available Global climate change is projected to continue and result in prolonged and more intense droughts, which can increase soil water repellency (SWR. To be able to estimate the consequences of SWR on vadose zone hydrology, it is important to determine soil hydraulic properties (SHP. Sequential modeling using HYDRUS (2D/3D was performed on an experimental field site with artificially imposed drought scenarios (moderately M and severely S stressed and a control plot. First, inverse modeling was performed for SHP estimation based on water and ethanol infiltration experimental data, followed by model validation on one selected irrigation event. Finally, hillslope modeling was performed to assess water balance for 2014. Results suggest that prolonged dry periods can increase soil water repellency. Inverse modeling was successfully performed for infiltrating liquids, water and ethanol, with R2 and model efficiency (E values both > 0.9. SHP derived from the ethanol measurements showed large differences in van Genuchten-Mualem (VGM parameters for the M and S plots compared to water infiltration experiments. SWR resulted in large saturated hydraulic conductivity (Ks decrease on the M and S scenarios. After validation of SHP on water content measurements during a selected irrigation event, one year simulations (2014 showed that water repellency increases surface runoff in non-structured soils at hillslopes.

  1. Response of CO and H2 uptake to extremes of water stress in saline and non-saline soils

    Science.gov (United States)

    King, G.

    2017-12-01

    Neither carbon monoxide (CO) nor hydrogen (H2) have direct impacts on radiative forcing, but both play important roles in tropospheric chemistry. Soils affect both the fate and significance of atmospheric CO and H2 by acting as strong global gas sinks ( 15% and >75 %, respectively), but much remains unknown about the microbiology of these gases, including responses to key environmental drivers. The role of water availability, measured as water potential, has been addressed to a limited extent by earlier studies with results suggesting that CO and H2 uptake are strongly limited by water stress. However recent results indicate a much greater tolerance of water stress than previously suspected. Ex situ assays have shown that non-saline playa soils from the Alvord Basin (Oregon, USA) consumed atmospheric and exogenous hydrogen and CO under conditions of severe water stress. CO uptake occurred at water potentials values considered optimal for terrestrial bacterial growth. Surface soils that had been exposed to water potentials as low as -300 MPa also oxidized CO and H2 after brief equilibration at higher potentials (less water stress), indicating remarkable tolerance of desiccating conditions. Tolerance to water stress for CO and H2 uptake was also observed for soils from a montane rainforest (Hawai`i, USA). However, unlike playa soils rainforest soils seldom experience extended drought that would select for desiccation tolerance. While CO uptake by forest soils was more sensitive to water stress (limits -10MPa) than in playa soils, H2 uptake was observed at -90 MPa to -100 MPa. Tolerance at these levels might be due to the formation of intracellular water that limits the local effects of stress. Comparisons of water stress responses between saline and non-saline soils further suggested that communities of CO- and H2-oxidizing were generally robust with respect to stresses resulting from solute and matric effects. Collectively the results indicate that models of global

  2. Selective control of photodissociation in deutereted water molecule HOD

    International Nuclear Information System (INIS)

    Adhikari, S.; Deshpande, Sarin; Sarma, Manabendra; Kurkal, Vandana; Mishra, M.K.

    2006-01-01

    Bond dissociation in the deutereted water molecule HOD has been investigated to explore the possibility of selective control of dissociation of O-H and O-D bonds using simple field profiles and initial states that do not require high overtone excitations. Preliminary results indicate that considerable selectivity in dissociation of O-H and O-D bonds can be achieved using fundamental and first overtone excitations only and use of field optimized initial state (FOIST) based scheme with appropriate choice of field parameters and initial states may enhance both selectivity and yield

  3. Radionuclide analysis of drinking water in selected secondary ...

    African Journals Online (AJOL)

    Radionuclide analysis of drinking water in selected secondary schools of Epe ... obtained were in the ranges of (38.3 – 292.8) Bq/L with mean value of 13.4 + 10.8 ... and within the tolerance level indicating minimal radiological health burden.

  4. Potability Evaluation of Selected River Waters in Ebonyi State, Nigeria

    Directory of Open Access Journals (Sweden)

    J. I. Awu

    2015-06-01

    Full Text Available The study focused on the seasonal variation of physiochemical and microbial characteristics of three selected river water in Ebonyi State for human consumption. The three selected rivers studied were Iyioka, Idima and Ubei Rivers. Data were generated using Direct Reading Engineering method (DREM, Gravimetric method, Titrimetric method, Spectrophotometric method, Atomic Absorption Spectrophotometric method, and Total Viable count for physiochemical and microbiological analysis. The generated data was further subjected to statistical analysis using one way analysis of variance (ANOVA on difference between means of parameters and graphical method to determine the spatial variation of the water quality characteristics. The time variations of the water quality characteristics as compared with the spatial variations showed that for some variables, there was statistical difference between the means of parameters with respect to time and space at various levels of significance. These include Phosphorus (5%, Copper (1%, Iron (5%, Nickel (5%, Cadmium (1%, Salinity (1%, Bacteria (1% for time variation; and Sulphate (1%, Chemical Oxygen (5%,Nickel (1%, Arsenic (1%, Zinc (1%, Cadmium (1%, Bacteria (1% for spatial variations during dry season and Chemical Oxygen (5%, Nickel (1%, for spatial variation during rainy season. Based on the World Health Organization and Standard Organization of Nigeria guidelines for drinking water, the results of microbial analysis also indicated that the selected river waters were polluted with disease causing microorganisms, such as E.Coliform, Salmonella, Bacillus Subtilis. Therefore, the river waters are not good for drinking. The consumers of water obtained from the three rivers are likely to suffer the following: typhoid, fever, intestinal problem, diarrhea, skin rash, cholera. Necessary recommendations such as treating the water with bio-sand filter before use, amongst others, were made.

  5. Water stress and harmful insects in agri-forest ecosystems

    Directory of Open Access Journals (Sweden)

    Mario Solinas

    2010-09-01

    Full Text Available Present knowledge on ecological services supplied by insects to natural terrestrial ecosystems, allow us to identify many homeostatic mechanisms regulating biological balance as well as life perpetuation of the said ecosystems; at the same time, that knowledge represents a sound referring point to understanding how those mechanisms do work so as to manage them in the anthropized ecosystems (i.e., agriculture and forests, and especially in order to identify in the latter the natural meaning of the so called insect outbreaks, so as to forecast and possibly prevent them; as well as, when needed, to conceive and formulate efficient control strategies having minimal environmental impact. Water factor is crucial with genesis, configuration and conservation of a terrestrial ecosystem (both natural or anthropized as a whole or in its individual components, but especially concerning plant life as well as plant interactions with phytophagous invertebrates, mainly insects. Insect-plant trophic interactions are principally influenced by the water conditions in the ecosystem, and the impact of phytophagous insects on crops is markedly affected. Extremely severe water stress, especially if prolonged, prevent insect life just like plant’s life but a moderate and not so prolonged water stress, while depressing plant vigour, paradoxically can improve development and multiplication of phytophagous arthropods, with severe consequences on woody plants especially, and forest trees markedly.

  6. Water stress and harmful insects in agri-forest ecosystems

    Directory of Open Access Journals (Sweden)

    Mario Solinas

    2011-02-01

    Full Text Available Present knowledge on ecological services supplied by insects to natural terrestrial ecosystems, allow us to identify many homeostatic mechanisms regulating biological balance as well as life perpetuation of the said ecosystems; at the same time, that knowledge represents a sound referring point to understanding how those mechanisms do work so as to manage them in the anthropized ecosystems (i.e., agriculture and forests, and especially in order to identify in the latter the natural meaning of the so called insect outbreaks, so as to forecast and possibly prevent them; as well as, when needed, to conceive and formulate efficient control strategies having minimal environmental impact. Water factor is crucial with genesis, configuration and conservation of a terrestrial ecosystem (both natural or anthropized as a whole or in its individual components, but especially concerning plant life as well as plant interactions with phytophagous invertebrates, mainly insects. Insect-plant trophic interactions are principally influenced by the water conditions in the ecosystem, and the impact of phytophagous insects on crops is markedly affected. Extremely severe water stress, especially if prolonged, prevent insect life just like plant’s life but a moderate and not so prolonged water stress, while depressing plant vigour, paradoxically can improve development and multiplication of phytophagous arthropods, with severe consequences on woody plants especially, and forest trees markedly.

  7. Water stress and harmful insects in agri-forest ecosystems

    Directory of Open Access Journals (Sweden)

    Mario Solinas

    Full Text Available Present knowledge on ecological services supplied by insects to natural terrestrial ecosystems, allow us to identify many homeostatic mechanisms regulating biological balance as well as life perpetuation of the said ecosystems; at the same time, that knowledge represents a sound referring point to understanding how those mechanisms do work so as to manage them in the anthropized ecosystems (i.e., agriculture and forests, and especially in order to identify in the latter the natural meaning of the so called insect outbreaks, so as to forecast and possibly prevent them; as well as, when needed, to conceive and formulate efficient control strategies having minimal environmental impact. Water factor is crucial with genesis, configuration and conservation of a terrestrial ecosystem (both natural or anthropized as a whole or in its individual components, but especially concerning plant life as well as plant interactions with phytophagous invertebrates, mainly insects. Insect-plant trophic interactions are principally influenced by the water conditions in the ecosystem, and the impact of phytophagous insects on crops is markedly affected. Extremely severe water stress, especially if prolonged, prevent insect life just like plant’s life but a moderate and not so prolonged water stress, while depressing plant vigour, paradoxically can improve development and multiplication of phytophagous arthropods, with severe consequences on woody plants especially, and forest trees markedly.

  8. Remote sensing of water and nitrogen stress in broccoli

    Science.gov (United States)

    Elsheikha, Diael-Deen Mohamed

    Remote sensing is being used in agriculture for crop management. Ground based remote sensing data acquisition system was used for collection of high spatial and temporal resolution data for irrigated broccoli crop. The system was composed of a small cart that ran back and forth on a rail system that was mounted on a linear move irrigation system. The cart was equipped with a sensor that had 4 discrete wavelengths; 550 nm, 660 nm, 720 nm, and 810 nm, and an infrared thermometer, all had 10 nm bandwidth. A global positioning system was used to indicate the cart position. The study consisted of two parts; the first was to evaluate remotely sensed reflectance and indices in broccoli during the growing season, and determine whether remotely sensed indices or standard deviation of indices can distinguish between nitrogen and water stress in broccoli, and the second part of the study was to evaluate remotely sensed indices and standard deviation of remotely sensed indices in broccoli during daily changes in solar zenith angle. Results indicated that nitrogen was detected using Ratio Vegetation index, RVI, Normalized Difference Vegetation Index, NDVI, Canopy Chlorophyll Concentration Index, CCCI, and also using the reflectance in the Near-Infrared, NIR, bands. The Red reflectance band capability of showing stress was not as clear as the previous indices and bands reflectance. The Canopy Chlorophyll Concentration Index, CCCI, was the most successful index. The Crop Water Stress Index was able to detect water stress but it was highly affected by the solar zenith angle change along the day.

  9. The effects of stress and sex on selection, genetic covariance, and the evolutionary response.

    Science.gov (United States)

    Holman, L; Jacomb, F

    2017-10-01

    The capacity of a population to adapt to selection (evolvability) depends on whether the structure of genetic variation permits the evolution of fitter trait combinations. Selection, genetic variance and genetic covariance can change under environmental stress, and males and females are not genetically independent, yet the combined effects of stress and dioecy on evolvability are not well understood. Here, we estimate selection, genetic (co)variance and evolvability in both sexes of Tribolium castaneum flour beetles under stressful and benign conditions, using a half-sib breeding design. Although stress uncovered substantial latent heritability, stress also affected genetic covariance, such that evolvability remained low under stress. Sexual selection on males and natural selection on females favoured a similar phenotype, and there was positive intersex genetic covariance. Consequently, sexual selection on males augmented adaptation in females, and intralocus sexual conflict was weak or absent. This study highlights that increased heritability does not necessarily increase evolvability, suggests that selection can deplete genetic variance for multivariate trait combinations with strong effects on fitness, and tests the recent hypothesis that sexual conflict is weaker in stressful or novel environments. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

  10. ADRA2B deletion variant selectively predicts stress-induced enhancement of long-term memory in females.

    Science.gov (United States)

    Zoladz, Phillip R; Kalchik, Andrea E; Hoffman, Mackenzie M; Aufdenkampe, Rachael L; Lyle, Sarah M; Peters, David M; Brown, Callie M; Cadle, Chelsea E; Scharf, Amanda R; Dailey, Alison M; Wolters, Nicholas E; Talbot, Jeffery N; Rorabaugh, Boyd R

    2014-10-01

    Clarifying the mechanisms that underlie stress-induced alterations of learning and memory may lend important insight into susceptibility factors governing the development of stress-related psychological disorders, such as post-traumatic stress disorder (PTSD). Previous work has shown that carriers of the ADRA2B Glu(301)-Glu(303) deletion variant exhibit enhanced emotional memory, greater amygdala responses to emotional stimuli and greater intrusiveness of traumatic memories. We speculated that carriers of this deletion variant might also be more vulnerable to stress-induced enhancements of long-term memory, which would implicate the variant as a possible susceptibility factor for traumatic memory formation. One hundred and twenty participants (72 males, 48 females) submerged their hand in ice cold (stress) or warm (no stress) water for 3min. Immediately afterwards, they studied a list of 42 words varying in emotional valence and arousal and then completed an immediate free recall test. Twenty-four hours later, participants' memory for the word list was examined via free recall and recognition assessments. Stressed participants exhibiting greater heart rate responses to the stressor had enhanced recall on the 24-h assessment. Importantly, this enhancement was independent of the emotional nature of the learned information. In contrast to previous work, we did not observe a general enhancement of memory for emotional information in ADRA2B deletion carriers. However, stressed female ADRA2B deletion carriers, particularly those exhibiting greater heart rate responses to the stressor, did demonstrate greater recognition memory than all other groups. Collectively, these findings implicate autonomic mechanisms in the pre-learning stress-induced enhancement of long-term memory and suggest that the ADRA2B deletion variant may selectively predict stress effects on memory in females. Such findings lend important insight into the physiological mechanisms underlying stress

  11. Selection for stress responsiveness and slaughter stress affect flesh quality in pan-size rainbow trout, Oncorhynchus mykiss

    OpenAIRE

    Lefevre, Florence; Cos, Isabelle; Pottinger, Tom G.; Bugeon, Jérôme

    2016-01-01

    The control of slaughter stress is of importance with regard to both fish welfare and flesh quality. Muscle characteristics and instrumentally measured quality parameters were determined in rainbow trout lines selected for high-responsiveness (HR) or low-responsiveness (LR) of plasma cortisol to an acute confinement stressor. Measurements were made in both unstressed and stressed fish (a 15 min period of confinement before slaughter) from both lines. Compared to LR fish, HR fish were smaller,...

  12. Unconventional oil and gas development and its stresses on water resources in the context of Water-Energy-Food Nexus: The case of Weld County, Colorado

    Science.gov (United States)

    Oikonomou, P. D.; Waskom, R.; Boone, K.; Ryan, J. N.

    2015-12-01

    The development of unconventional oil and gas resources in Colorado started to rapidly increase since the early 2000's. The recent oil price plunge resulted in a decline of well starts' rate in the US, but in Weld County, Colorado, it is currently at the 2013-levels. The additional water demand, despite its insignificant percentage in overall state's demand (0.1% in 2012), it competes with traditional ones, since Colorado's water is almost fully appropriated. Presently, the state has 53,597 active producing oil and gas wells. More than 40% of these are located in Weld County, which happens also to be one of top food production U.S. counties. The competition for land and water resources between the energy and agricultural sectors in water stressed areas, like the western U.S., is further intensified if recycle and reuse practices are not preferred to water disposal by the energy industry. Satisfying the multiple objectives of the Water-Energy-Food Nexus in order to achieve sustainable economic development requires balanced management of these resources. Identifying pressures on key areas that food and energy sectors are competing for water, is essential for prudent water management and developing appropriate policies. Weld County, as a water stressed and fossil fuel producing area, was selected for investigating current stresses on local water resources alongside with future climatic and water demand scenarios for exploring probable long-term effects.

  13. Analysis of the Citrullus colocynthis transcriptome during water deficit stress.

    Directory of Open Access Journals (Sweden)

    Zhuoyu Wang

    Full Text Available Citrullus colocynthis is a very drought tolerant species, closely related to watermelon (C. lanatus var. lanatus, an economically important cucurbit crop. Drought is a threat to plant growth and development, and the discovery of drought inducible genes with various functions is of great importance. We used high throughput mRNA Illumina sequencing technology and bioinformatic strategies to analyze the C. colocynthis leaf transcriptome under drought treatment. Leaf samples at four different time points (0, 24, 36, or 48 hours of withholding water were used for RNA extraction and Illumina sequencing. qRT-PCR of several drought responsive genes was performed to confirm the accuracy of RNA sequencing. Leaf transcriptome analysis provided the first glimpse of the drought responsive transcriptome of this unique cucurbit species. A total of 5038 full-length cDNAs were detected, with 2545 genes showing significant changes during drought stress. Principle component analysis indicated that drought was the major contributing factor regulating transcriptome changes. Up regulation of many transcription factors, stress signaling factors, detoxification genes, and genes involved in phytohormone signaling and citrulline metabolism occurred under the water deficit conditions. The C. colocynthis transcriptome data highlight the activation of a large set of drought related genes in this species, thus providing a valuable resource for future functional analysis of candidate genes in defense of drought stress.

  14. Growth and yield response of wheat varieties to water stress at booting and anthesis stages of development

    International Nuclear Information System (INIS)

    Khakwani, A.A.; Abid, M.

    2012-01-01

    Plants of 6 bread wheat varieties (Damani, Hashim-8, Gomal-8, DN-73, Zam-04 and Dera-98) were subjected to 2 treatments i.e., control treatment (100% field capacity) and stressed treatment (20 days water stress was given during booting stage and 20 days water stress after anthesis). The findings revealed highly significant differences among means of wheat varieties in all physiological and yield traits. Almost all varieties showed their best adaptation under stressed environment however Hashim-8 and Zam-04 behaved exclusively and indicated higher relative water content (RWC), mean productivity (MP), geometric mean productivity (GMP) and stress tolerance index (STI) whereas stress susceptibility index (SSI) and tolerance (TOL) was estimated at its lowest, as these traits are recognised beneficial drought tolerance indicators for selection of a stress tolerant variety. Similarly, total grain yield per plant, biological yield per plant and harvest index was also higher in the same wheat varieties that put them as good candidates for selection criteria in wheat breeding program for drought resistant. (author)

  15. thermal stress and Hsp70 as selective agents

    Indian Academy of Sciences (India)

    Madhu Sudhan

    starred in an exhaustive list of studies linking its expression to environmental ... genetic stress linked to Hsp70: polyglutamine expansion .... Twenty-five D. melanogaster genes conserved in all twelve Drosophila species (fourth column) possessing conserved ...... like growth factor-1, and vertebral bone mass in men; J. Clin.

  16. Temporal versus spatial variation in leaf reflectance under changing water stress conditions

    Science.gov (United States)

    Cohen, Warren B.

    1991-01-01

    Leaf reflectance changes associated with changes in water stress were analyzed in two separate experiments. Results indicate that the variation in reflectance among collections of leaves of a given species all at the same level of water stress is at least as great as the variation in reflectance associated with changes in water stress for a given leaf collection of that species. The implications is that results from leaf reflectance-water stress studies have only limited applicability to the remote sensing of plant canopy water stress.

  17. Abscisic acid biosynthesis in water-stressed leaves

    International Nuclear Information System (INIS)

    Li, Yi.

    1989-01-01

    Although abscisic acid (ABA) was discovered 30 years ago, very little is known about its biosynthetic pathway in higher plants. Two hypotheses have been proposed: (i) a direct pathway involving only C-15 intermediates like farnesyl pyrophosphate, (ii) an indirect pathway involving C-40 intermediates like the xanthophylls. When 14 CO 2 was fed into greened bean plants, the 14 C specific activity of ABA was always lower than those in xanthophylls, such as violaxanthin and lutein, regardless of 12 CO 2 chase periods. The ABA accumulation in green leaves was not affected by fluridone when plants were stressed once, but the 14 C incorporation into ABA was inhibited to the same extent as those of xanthophylls. The incorporation of 18 O into the ABA ring when violaxanthin was labeled by 18 O in vivo via the violaxanthin cycle indicates that at least a portion of ABA was derived from 18 O-labeled violaxanthin during water stress

  18. Selective absorption of water from different oil–water emulsions with ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 30; Issue 4. Selective absorption of water from different oil–water emulsions with Psy-cl-poly(AAm) synthesized using irradiation copolymerization method. B S Kaith Kiran Kumar. Polymers Volume 30 Issue 4 August 2007 pp 387-391 ...

  19. Influence of irrigation water types and stress levels on cotton fibre and yarn quality for different varieties

    International Nuclear Information System (INIS)

    Nazar, A.; Ishaq, W.

    2012-01-01

    Cotton fibre quality is being deteriorated day by day due to various reasons and shortage/ poor quality of irrigation water is one of the reasons for the low quality of cotton fibre. The effect of the stress of water can be seen on the fibre length, strength and elongation. All these properties of fibre have also a significant influence on yarn characteristics and thus the yarn quality is also dependent on agronomic practices including irrigation. When new varieties are evolved it becomes necessary to examine such cotton varieties keenly, so that one which reflects maximum agricultural as well as industrial benefits can be recommended. The present study was planned to explore the spinning performance of various cotton varieties under different water quality treatments and water stress levels. Cotton of four varieties (CIM-501, CIM-496, CIM-499, and NIAB-111) under different types of irrigation water (canal water and tube well water) and different water stress levels (75ET, 100ET and 125ET) were selected for this research. The effect of these treatments was investigated on cotton fibre span length, strength and fibre elongation as well as on yarn quality. The study revealed that effect of different cotton varieties, water types and water stress levels on fibre and yarn quality was highly significant. Yarn characteristics showed greater values for the canal water similarly fibre length and elongations were better for canal water. Yarn tensile properties were decreased with increase in the water stress. The overall results indicated that the cotton variety NIAB-111 performed better as compared to other varieties. It is suggested that the cotton farmers may be trained by the agri. extension staff regarding maintenance of fibre quality through cultural practices and better irrigation techniques. (author)

  20. Cowpea bean production under water stress using hydrogels

    Directory of Open Access Journals (Sweden)

    Marília Barcelos Souza Lopes

    2017-03-01

    Full Text Available The population increase and the need of intensifying food production, coupled with the scarcity of water resources, have led to the search of alternatives that reduce consumption and optimize the water use during cultivation. In this context, hydrogels become a strategy in agricultural management, due to their water retention capacity in the soil and availability to plants. This study aimed at evaluating the efficiency of hydrogels on the development and production of cowpea bean ('Sempre-verde' cultivar under water stress, in a greenhouse. The experiment was performed in a randomized block design, with five replications, in a 4 x 5 factorial scheme, consisting of four types of hydrogel (Hydroplan-EB HyA, with granulometry of 1-3 mm; Hydroplan-EB HyB, with granulometry of 0.5-1 mm; Hydroplan-EB HyC, with granulometry < 0.5 mm; Polim-Agri, with granulometry of 1-0.5 mm and five concentrations (0 g pot-1; 1.5 g pot-1; 3 g pot-1; 4.5 g pot-1; 6 g pot-1. The following traits were evaluated: number of pods per plant, number of grains per pod and grain yield. The highest concentration (6 g pot-1 resulted in a higher number of pods and yield for all the hydrogels, especially for HyC and Polim-Agro, which presented 7.4 pods plant-1 and 7.0 pods plant-1, with yield of 15.43 g plant-1 and 16.68 g plant-1, respectively. The use of hydrogel shows to be efficient for reducing yield losses under water stress.

  1. Crop coefficient, yield response to water stress and water productivity of teff (Eragrostis tef (Zucc.)

    NARCIS (Netherlands)

    Araya, A.; Stroosnijder, L.; Girmay, G.; Keesstra, S.D.

    2011-01-01

    In the semi-arid region of Tigray, Northen Ethiopia a two season experiment was conducted to measure evapotranspiration, estimate yield response to water stress and derive the crop coefficient of teff using the single crop coefficient approach with simple, locally made lysimeters and field plots.

  2. STRESS RELAXATION CHARACTERISTICS OF SELECTED COMMERCIALLY PRODUCED GLASSES

    Directory of Open Access Journals (Sweden)

    Chocholoušek J.

    2013-06-01

    Full Text Available This paper describes a quantitative method of stress relaxation measurement in prismatic glass samples during two different time-temperature regimes using the Sénarmont compensator. Four types of glass (Barium crystal glass, Eutal, Simax, and Container glass were subjected to observation in an assembled measuring device. Results will be used for parameterization of the Tool-Narayanaswamy-Mazurin model and consequently implemented in a finite element method code.

  3. A Review of Selected Literature on Stresses Affecting Soldiers in Combat

    Science.gov (United States)

    1979-05-01

    14 W. D. Chiles . Psycho logicat Stress as a Theoretical Concept, WADC Technical Report 57-457, Wright Air Development Center, Wright- Patterson AFB...placing the bulb of the thermometer in a water saturated 1M. J. Duke, N. Findikyan, J. Anderson, and S. B. Sells. Stress /N Vih ,:;. [I. ’Aheriarn7...to stress. Concern with fatigue and its effects have led to a considerable amount of work in the past two decades. Chiles , Alluisi, and Adams 30

  4. In vitro screening of durum wheat against water-stress mediated through polyethylene glycol

    Directory of Open Access Journals (Sweden)

    Nadia Sandra Kacem

    2017-06-01

    Full Text Available Three durum wheat (Triticum durum Desf. genotypes with three levels of drought tolerance were screened in order to evaluate their response to water stress at callus induction and plant regeneration levels. Significant differences were observed among the genotypes, and polyethylene glycol (PEG levels used, and their interactions were however, significant for all the studied characters. Increase in PEG concentration increased the time required for callus initiation and reduced the number of calli frequency of embryogenic structures and number of plants regenerated, showing the adverse effect of PEG on the somatic embryogenesis developmental., under in vitro conditions tested, and Djenah Khetifa was the most tolerant genotype, followed by Oued Zenati and Waha. This pattern was per their drought tolerance behavior under field conditions. Principal component analysis (PCA showed that 95.56% of the total variation was explained by the first two principal components. Biplot analysis allowed the stress-tolerant genotype to be distinguished from the two less tolerant genotypes. Time required for callus initiation was strongly negatively correlated with all other studied traits. These traits can be recommended as suitable selection criteria for screening drought-tolerant genotypes. The selected cells and plants will provide a tool for determining the mechanisms involved in tolerance to water stress.

  5. The effects of social stress and cortisol responses on the preconscious selective attention to social threat

    NARCIS (Netherlands)

    Roelofs, K.; Bakvis, P.; Hermans, E.J.; Pelt, J. van; Honk, E.J. van

    2007-01-01

    The purpose of the present study was to investigate the effects of social stress and stress-induced cortisol on the preconscious selective attention to social threat. Twenty healthy participants were administered a masked emotional Stroop task (comparing color-naming latencies for angry, neutral and

  6. The effects of social stress and cortisol responses on the preconscious selective attention to social threat.

    NARCIS (Netherlands)

    Roelofs, K.; Bakvis, P.; Hermans, E.J.; Pelt, J. van; Honk, E.J. van

    2007-01-01

    The purpose of the present study was to investigate the effects of social stress and stress-induced cortisol on the preconscious selective attention to social threat. Twenty healthy participants were administered a masked emotional Stroop task (comparing color-naming latencies for angry, neutral and

  7. THE INFLUENCE OF SELECTED ORGANIC MICROPOLLUTANTS ON WATER ECOSYSTEMS

    Directory of Open Access Journals (Sweden)

    Edyta Anna Kudlek

    2017-06-01

    Full Text Available The paper presents a literature review in terms of the impact of selected micropollutants from the group of pharmaceutical compounds, food preservatives, pesticides and organic UV filters on various plants and animals species, which inhabit the water ecosystems. During own studies the impact of concentrations of micropollutants in the water environment on selected indicator organisms was evaluated. The study was conducted using saltwater Aliivibrio fischer bacteria, freshwater Daphnia magna and saltwater Artemia fanciscana crustaceans, as well as vascular plants Lemna minor. It was shown that the test organisms are characterized by a different sensitivity for the presence of micropollutants. For all applied tests an increase in the response of indicator organisms with the increasing compound concentration was observed. It demonstrates the growing toxic impact of micropollutants. The solution of benzophenone-3 at a concentration of 5 mg/dm3 was characterized by the highest toxic effects against both bacteria, crustaceans and vascular plants.

  8. Evidence for a role of claudin 2 as a proximal tubular stress responsive paracellular water channel

    Energy Technology Data Exchange (ETDEWEB)

    Wilmes, Anja, E-mail: Anja.Wilmes@i-med.ac.at; Aschauer, Lydia; Limonciel, Alice; Pfaller, Walter; Jennings, Paul

    2014-09-01

    Claudins are the major proteins of the tight junctions and the composition of claudin subtypes is decisive for the selective permeability of the paracellular route and thus tissue specific function. Their regulation is complex and subject to interference by several factors, including oxidative stress. Here we show that exposure of cultured human proximal tubule cells (RPTEC/TERT1) to the immunosuppressive drug cyclosporine A (CsA) induces an increase in transepithelial electrical resistance (TEER), a decrease in dome formation (on solid growth supports) and a decrease in water transport (on microporous growth supports). In addition, CsA induced a dramatic decrease in the mRNA for the pore forming claudins -2 and -10, and the main subunits of the Na{sup +}/K{sup +} ATPase. Knock down of claudin 2 by shRNA had no discernable effect on TEER or dome formation but severely attenuated apical to basolateral water reabsorption when cultured on microporous filters. Generation of an osmotic gradient in the basolateral compartment rescued water transport in claudin 2 knock down cells. Inhibition of Na{sup +}/K{sup +} ATPase with ouabain prevented dome formation in both cell types. Taken together these results provide strong evidence that dome formation is primarily due to transcellular water transport following a solute osmotic gradient. However, in RPTEC/TERT1 cells cultured on filters under iso-osmotic conditions, water transport is primarily paracellular, most likely due to local increases in osmolarity in the intercellular space. In conclusion, this study provides strong evidence that claudin 2 is involved in paracellular water transport and that claudin 2 expression is sensitive to compound induced cellular stress. - Highlights: • Cyclosporine A increased TEER and decreased water transport in RPTEC/TERT1 cells. • Claudins 2 and 10 were decreased in response to cyclosporine A. • Knock down of claudin 2 inhibited water transport in proximal tubular cells. • We

  9. The role of perceived stress and gender on portion selection patterns.

    Science.gov (United States)

    Lim, E X; Sim, A Y; Forde, C G; Cheon, B K

    2018-06-01

    Stress is linked to increased preferences and consumption of palatable energy dense foods, particularly among females. Despite the role of stress on potentially obesogenic eating habits, its effect on pre-meal planning, such as the selection of portion sizes, remain unknown. Here, we investigated the relationship between perceived stress, gender, and intended portion sizes for diverse foods. Across two studies, increased perceived stress predicted larger (higher energy) intended portion sizes across a variety of food items among females, but not males. Additionally, for females, increased perceived stress was associated with lowered expectations of the satiety of foods presented, suggesting a potential mechanism by which stress may influence decisions about portion size. These findings reveal that the potentially obesogenic effects of stress on food judgments and behaviours (particularly among females) are not only expressed within meals, but also during more deliberate stages of planning that precedes meals. Copyright © 2018 Elsevier Inc. All rights reserved.

  10. Isolation and characterization of a water stress-specific genomic gene, pwsi 18, from rice.

    Science.gov (United States)

    Joshee, N; Kisaka, H; Kitagawa, Y

    1998-01-01

    One of the water stress-specific cDNA clones of rice characterised previously, wsi18, was selected for further study. The wsi18 gene can be induced by water stress conditions such as mannitol, NaCl, and dryness, but not by ABA, cold, or heat. A genomic clone for wsi18, pwsi18, contained about 1.7 kbp of the 5' upstream sequence, two introns, and the full coding sequence. The 5'-upstream sequence of pwsi18 contained putative cis-acting elements, namely an ABA-responsive element (ABRE), three G-boxes, three E-boxes, a MEF-2 sequence, four direct and two inverted repeats, and four sequences similar to DRE, which is involved in the dehydration response of Arabidopsis genes. The gusA reporter gene under the control of the pwsi18 promoter showed transient expression in response to water stress. Deletion of the downstream DRE-like sequence between the distal G-boxes-2 and -3 resulted in rather low GUS expression.

  11. Selection criteria for water disinfection techniques in agricultural practices.

    Science.gov (United States)

    Haute, Sam van; Sampers, Imca; Jacxsens, Liesbeth; Uyttendaele, Mieke

    2015-01-01

    This paper comprises a selection tool for water disinfection methods for fresh produce pre- and postharvest practices. A variety of water disinfection technologies is available on the market and no single technology is the best choice for all applications. It can be difficult for end users to choose the technology that is best fit for a specific application. Therefore, the different technologies were characterized in order to identify criteria that influence the suitability of a technology for pre- or postharvest applications. Introduced criteria were divided into three principal components: (i) criteria related to the technology and which relate to the disinfection efficiency, (ii) attention points for the management and proper operation, and (iii) necessities in order to sustain the operation with respect to the environment. The selection criteria may help the end user of the water disinfection technology to obtain a systematic insight into all relevant aspects to be considered for preliminary decision making on which technologies should be put to feasibility testing for water disinfection in pre- and postharvest practices of the fresh produce chain.

  12. Response of Thematic Mapper bands to plant water stress

    Science.gov (United States)

    Cibula, W. G.; Zetka, E. F.; Rickman, D. L.

    1992-01-01

    Changes in leaf reflectance as water content decreases have been hypothesized to occur in the 1.55-1.75 and 2.08-2.35 micron wavelength regions. To evaluate this hypothesis, studies were conducted on ryegrass (Lolium multiflorum Lam.) and oats (Avena sativa L.), which were grown in a controlled, outdoor situation. Both fully-watered control beds and water-stressed beds were periodically examined with a spectroradiometer calibrated against a reflectance reference of polytetrafluoroethylene. The observed changes correspond to those predicted by stochastic leaf models employed by other investigators (leaf reflection increases in the 1.55-1.75 micron region as leaf water content decreases). Although the percentage changes in TM bands 1-3 are nearly as great as those found in TM bands 5 and 7, the absolute values of reflectance change are much lower. It is believed that these patterns are probably characteristic of a broad range of vegetation types. In terms of phenomena detection, these patterns should be considered in any practical remote sensing sensor scenario.

  13. Comparative leaf proteomics of drought-tolerant and -susceptible peanut in response to water stress

    Science.gov (United States)

    Water stress (WS) predisposes peanut plants to fungal infection resulting in pre-harvest aflatoxin contamination. Major changes during water stress including oxidative stress, lead to destruction of photosynthetic apparatus and other macromolecules within cells. Two peanut cultivars with diverse dro...

  14. Selecting downscaled climate projections for water resource impacts and adaptation

    Science.gov (United States)

    Vidal, Jean-Philippe; Hingray, Benoît

    2015-04-01

    Increasingly large ensembles of global and regional climate projections are being produced and delivered to the climate impact community. However, such an enormous amount of information can hardly been dealt with by some impact models due to computational constraints. Strategies for transparently selecting climate projections are therefore urgently needed for informing small-scale impact and adaptation studies and preventing potential pitfalls in interpreting ensemble results from impact models. This work proposes results from a selection approach implemented for an integrated water resource impact and adaptation study in the Durance river basin (Southern French Alps). A large ensemble of 3000 daily transient gridded climate projections was made available for this study. It was built from different runs of 4 ENSEMBLES Stream2 GCMs, statistically downscaled by 3 probabilistic methods based on the K-nearest neighbours resampling approach (Lafaysse et al., 2014). The selection approach considered here exemplifies one of the multiple possible approaches described in a framework for identifying tailored subsets of climate projections for impact and adaptation studies proposed by Vidal & Hingray (2014). It was chosen based on the specificities of both the study objectives and the characteristics of the projection dataset. This selection approach aims at propagating as far as possible the relative contributions of the four different sources of uncertainties considered, namely GCM structure, large-scale natural variability, structure of the downscaling method, and catchment-scale natural variability. Moreover, it took the form of a hierarchical structure to deal with the specific constraints of several types of impact models (hydrological models, irrigation demand models and reservoir management models). The implemented 3-layer selection approach is therefore mainly based on conditioned Latin Hypercube sampling (Christierson et al., 2012). The choice of conditioning

  15. Net carbon allocation in soybean seedlings as influenced by soil water stress at two soil temperatures

    International Nuclear Information System (INIS)

    McCoy, E.L.; Boersma, L.; Ekasingh, M.

    1990-01-01

    The influence of water stress at two soil temperatures on allocation of net photoassimilated carbon in soybean (Glycine max [L.] Merr.) was investigated using compartmental analysis. The experimental phase employed classical 14 C labeling methodology with plants equilibrated at soil water potentials of -0.04, -0.25 and -0.50 MPa; and soil temperatures of 25 and 10C. Carbon immobilization in the shoot apex generally followed leaf elongation rates with decreases in both parameters at increasing water stress at both soil temperatures. However, where moderate water stress resulted in dramatic declines in leaf elongation rates, carbon immobilization rates were sharply decreased only at severe water stress levels. Carbon immobilization was decreased in the roots and nodules of the nonwater stressed treatment by the lower soil temperature. This relation was reversed with severe water stress, and carbon immobilization in the roots and nodules was increased at the lower soil temperature. Apparently, the increased demand for growth and/or carbon storage in these tissues with increased water stress overcame the low soil temperature limitations. Both carbon pool sizes and partitioning of carbon to the sink tissues increased with moderate water stress at 25C soil temperature. Increased pool sizes were consistent with whole plant osmotic adjustment at moderate water stress. Increased partitioning to the sinks was consistent with carbon translocation processes being less severely influenced by water stress than is photosynthesis

  16. Effect of soil water stress on yield and proline content of four wheat ...

    African Journals Online (AJOL)

    Effect of soil water stress on yield and proline content of four wheat lines. ... This field study was conducted to evaluate the effect of drought stress after anthesis on proline accumulation and wheat yield during 2008 at ... from 32 Countries:.

  17. The crop water stress index (CWSI) for drip irrigated cotton in a semi ...

    African Journals Online (AJOL)

    The crop water stress index (CWSI) for drip irrigated cotton in a semi-arid region of Turkey. ... Four irrigation treatments designated as full (I100) with no water stress and slight (DI70), moderate (DI50) and strong water ... from 32 Countries:.

  18. Water Stress Assessment in Jharkhand State Using Soil Data and GIS

    African Journals Online (AJOL)

    In this paper an attempt has been made to study the interrelationship of water resources available with that of soil class and its properties including soil drainage and erosional characteristics which has been used to generate drainage stress map and water stress map inferring the basic reason for water scarcity in the district ...

  19. The impacts of water stress on phloem transport in Douglas-fir trees

    Science.gov (United States)

    David Woodruff

    2014-01-01

    Despite the critical role that phloem plays in a number of plant functional processes and the potential impact of water stress on phloem structural and phloem sap compositional characteristics, little research has been done to examine how water stress influences phloem transport. The objectives of this study were to develop a more accurate understanding of how water...

  20. Governing Non-Potable Water-Reuse to Alleviate Water Stress: The Case of Sabadell, Spain

    Directory of Open Access Journals (Sweden)

    Marketa Šteflová

    2018-06-01

    Full Text Available The world will experience an estimated 40% freshwater supply shortage by 2030, converting water scarcity into one of the principal global challenges that modern society faces. Urban water reuse is recognized as a promising and necessary measure to alleviate the growing water stress in many regions. The transformation to widespread application of water-reuse systems requires major changes in the way water is governed, and countries such as Spain already find themselves involved in this process. Through the systematic assessment of the city of Sabadell (Spain, we aim to identify the main barriers, opportunities and transferable lessons that can enhance governance capacity to implement systems for non-potable reuse of treated wastewater in cities. It was found that continuous learning, the availability and quality of information, the level of knowledge, and strong agents of change are the main capacity-building priorities. On the other hand, awareness, multilevel network potential and implementing capacity are already well-established. It is concluded that in order to undertake a widespread application of water-reuse practices, criteria examining water quality according to its use need to be developed independently of the water’s origin. The development and implementation of such a legislative frame should be based on the experience of local water-reuse practices and continuous evaluation. Finally, the need for public engagement and adequate pricing mechanisms are emphasized.

  1. Sectoral contributions to surface water stress in the coterminous United States

    International Nuclear Information System (INIS)

    Averyt, K; Meldrum, J; Caldwell, P; Sun, G; McNulty, S; Huber-Lee, A; Madden, N

    2013-01-01

    Here, we assess current stress in the freshwater system based on the best available data in order to understand possible risks and vulnerabilities to regional water resources and the sectors dependent on freshwater. We present watershed-scale measures of surface water supply stress for the coterminous United States (US) using the water supply stress index (WaSSI) model which considers regional trends in both water supply and demand. A snapshot of contemporary annual water demand is compared against different water supply regimes, including current average supplies, current extreme-year supplies, and projected future average surface water flows under a changing climate. In addition, we investigate the contributions of different water demand sectors to current water stress. On average, water supplies are stressed, meaning that demands for water outstrip natural supplies in over 9% of the 2103 watersheds examined. These watersheds rely on reservoir storage, conveyance systems, and groundwater to meet current water demands. Overall, agriculture is the major demand-side driver of water stress in the US, whereas municipal stress is isolated to southern California. Water stress introduced by cooling water demands for power plants is punctuated across the US, indicating that a single power plant has the potential to stress water supplies at the watershed scale. On the supply side, watersheds in the western US are particularly sensitive to low flow events and projected long-term shifts in flow driven by climate change. The WaSSI results imply that not only are water resources in the southwest in particular at risk, but that there are also potential vulnerabilities to specific sectors, even in the ‘water-rich’ southeast. (letter)

  2. Brief, pre-learning stress reduces false memory production and enhances true memory selectively in females.

    Science.gov (United States)

    Zoladz, Phillip R; Peters, David M; Kalchik, Andrea E; Hoffman, Mackenzie M; Aufdenkampe, Rachael L; Woelke, Sarah A; Wolters, Nicholas E; Talbot, Jeffery N

    2014-04-10

    Some of the previous research on stress-memory interactions has suggested that stress increases the production of false memories. However, as accumulating work has shown that the effects of stress on learning and memory depend critically on the timing of the stressor, we hypothesized that brief stress administered immediately before learning would reduce, rather than increase, false memory production. In the present study, participants submerged their dominant hand in a bath of ice cold water (stress) or sat quietly (no stress) for 3 min. Then, participants completed a short-term memory task, the Deese-Roediger-McDermott paradigm, in which they were presented with 10 different lists of semantically related words (e.g., candy, sour, sugar) and, after each list, were tested for their memory of presented words (e.g., candy), non-presented unrelated "distractor" words (e.g., hat), and non-presented semantically related "critical lure" words (e.g., sweet). Stress, overall, significantly reduced the number of critical lures recalled (i.e., false memory) by participants. In addition, stress enhanced memory for the presented words (i.e., true memory) in female, but not male, participants. These findings reveal that stress does not unequivocally enhance false memory production and that the timing of the stressor is an important variable that could mediate such effects. Such results could have important implications for understanding the dependability of eyewitness accounts of events that are observed following stress. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Self-esteem, narcissism, and stressful life events: Testing for selection and socialization.

    Science.gov (United States)

    Orth, Ulrich; Luciano, Eva C

    2015-10-01

    We examined whether self-esteem and narcissism predict the occurrence of stressful life events (i.e., selection) and whether stressful life events predict change in self-esteem and narcissism (i.e., socialization). The analyses were based on longitudinal data from 2 studies, including samples of 328 young adults (Study 1) and 371 adults (Study 2). The effects of self-esteem and narcissism were mutually controlled for each other and, moreover, controlled for effects of depression. After conducting the study-level analyses, we meta-analytically aggregated the findings. Self-esteem had a selection effect, suggesting that low self-esteem led to the occurrence of stressful life events; however, this effect became nonsignificant when depression was controlled for. Regardless of whether depression was controlled for or not, narcissism had a selection effect, suggesting that high narcissism led to the occurrence of stressful life events. Moreover, stressful life events had a socialization effect on self-esteem, but not on narcissism, suggesting that the occurrence of stressful life events decreased self-esteem. Analyses of trait-state models indicated that narcissism consisted almost exclusively of perfectly stable trait variance, providing a possible explanation for the absence of socialization effects on narcissism. The findings have significant implications because they suggest that a person's level of narcissism influences whether stressful life events occur, and that self-esteem is shaped by the occurrence of stressful life events. Moreover, we discuss the possibility that depression mediates the selection effect of low self-esteem on stressful life events. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

  4. Selected bibliography on deuterium isotope effects and heavy water

    International Nuclear Information System (INIS)

    Dave, S.M.; Donde, M.M.

    1983-01-01

    In recent years, there has been a great deal of interest in using deuterium and heavy water not only in nuclear industry but also in various fields of basic as well as applied research in physics, chemistry and biology. As a result, the literature is being enriched with a large number of research papers and technical reports published each year. Thus, to enable the scientists to have an easy reference to these works, an endeavour has been made in this selected bibliography, to enlist the publications related to these fields. Since the interest is concerned mainly with heavy water production processes, deuterium isotope effects etc., several aspects (e.g. nuclear) of deuterium have not been covered here. The material in this bibliography which cites 2388 references has been classified under six broad headings, viz. (1) Production of heavy water, (2) Study of deuterium isotope effects, (3) Analysis and Properties of heavy water, (4) Laser Separation of deuterium, (5) Isotopic exchange reactions, and (6) Miscellaneous. The sources of information used for this compilation are chemical abstracts, nuclear science abstracts, INIS Atomindex and also some scattered search through journals and reports available in the B.A.R.C. library. However, in spite of sincere attempts for a wide coverage, no claim is being made towards the exhaustiveness of this bibliography. (author)

  5. Monitoring of water quality of selected wells in Brno district

    Directory of Open Access Journals (Sweden)

    Marková Jana

    2016-06-01

    Full Text Available The article deals with two wells in the country of Brno-district (Brčálka well and Well Olšová. The aim of work was monitoring of elementary parameters of water at regular monthly intervals to measure: water temperature, pH values, solubility oxygen and spring yield. According to the client's requirements (Lesy města Brno laboratory analyzes of selected parameters were done twice a year and their results were compared with Ministry of Health Decree no. 252/2004 Coll.. These parameters: nitrate, chemical oxygen demand (COD, calcium and magnesium and its values are presented in graphs, for ammonium ions and nitrite in the table. Graphical interpretation of spring yields dependence on the monthly total rainfall and dependence of water temperature on ambient temperature was utilized. The most important features of wells include a water source, a landmark in the landscape, aesthetic element or resting and relaxing place. Maintaining wells is important in terms of future generations.

  6. FOR SELECTED ORGANIC MICROPOLLUTANTS ELIMINATION AND CHANGE OF WATER TOXICITY

    Directory of Open Access Journals (Sweden)

    Mariusz Dudziak

    2016-12-01

    Full Text Available All of the available and applicable chemical oxidants were found to affect the quality of the treated water or wastewater. It has been commonly observed that the oxidation processes generate by-products, which often possess unknown biological activity. Accordingly, the present study assessed the degree of degradation of mixture of selected micropollutants and the change of the solution toxicity in the UV/TiO2/H2O2 hybrid process. Water containing bisphenol A and diclofenac at a concentration of 1 mg/dm3 was treated. For toxicological evaluation of solution sample were used three different tests, ie. enzymatic Microtox® using luminescent strain of marine bacteria Aliivibrio fischeri, survival of the crustaceans Daphnia magna and the growth of duckweed Lemna minor. Decomposition of tested micropollutants depend on the processing time and the type of the oxidizing compound. However, during the process we observed adverse effects of water toxicity. The toxicity was documented in both bacteria and water plant.

  7. Crop water-stress assessment using an airborne thermal scanner

    Science.gov (United States)

    Millard, J. P.; Jackson, R. D.; Reginato, R. J.; Idso, S. B.; Goettelman, R. C.

    1978-01-01

    An airborne thermal scanner was used to measure the temperature of a wheat crop canopy in Phoenix, Arizona. The results indicate that canopy temperatures acquired about an hour and a half past solar noon were well correlated with presunrise plant water tension, a parameter directly related to plant growth and development. Pseudo-colored thermal images reading directly in stress degree days, a unit indicative of crop irrigation needs and yield potential, were produced. The aircraft data showed significant within-field canopy temperature variability, indicating the superiority of the synoptic view provided by aircraft over localized ground measurements. The standard deviation between airborne and ground-acquired canopy temperatures was 2 C or less.

  8. Selection of arabica coffee progenies tolerant to heat stress

    Directory of Open Access Journals (Sweden)

    Alexsandro Lara Teixeira

    2015-07-01

    Full Text Available Due to high temperatures, practically all coffee farms in the state of Rondonia are of the C. canephora species. Thus, importing arabica coffee from other states becomes necessary for composition of blends, as well as for the specialty or gourmet coffee market. The purpose of this study was to select arabica coffee genotypes that exhibit satisfactory agronomic performance under high temperature conditions. The experiment was conducted in OuroPreto do Oeste, RO, Brazil, with mean annual temperature of 25.8°C and mean annual rainfall of 2300mm year-1. The experiment was composed of 114 arabica coffee genotypes, with 103 progenies and eleven control cultivars, provided by EPAMIG. A randomized block experimental design was used with three replications, spacing of 3.0x1.0 meters and five plants per plot. All the crop seasons showed significant difference for the green coffee yield trait. In joint analysis, significant differences were detected among progenies and control cultivars. In the average of the four harvests, green coffee yield was 32.38 bags ha-1. The cultivars 'CatuaíVermelho IAC 15', 'Obatã IAC 1669-20' and 'Catucaí Amarelo 2SLCAK' stood out, achieving yields greater than 40 bags ha-1. The gain obtained from selection was 14.33 bags ha-1, which is equivalent to an increase of 44.04% in production of green coffee. The progeny H514-7-10-6-2-3-9 stood out with an average yield of 51.20 bags ha-1. In regard to maturation cycle, 56% of the progenies were classified as early maturity and 44% as medium maturity. Late maturity genotypes were not observed

  9. Abscisic acid biosynthesis in water-stressed leaves

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yi.

    1989-01-01

    Although abscisic acid (ABA) was discovered 30 years ago, very little is known about its biosynthetic pathway in higher plants. Two hypotheses have been proposed: (i) a direct pathway involving only C-15 intermediates like farnesyl pyrophosphate, (ii) an indirect pathway involving C-40 intermediates like the xanthophylls. When {sup 14}CO{sub 2} was fed into greened bean plants, the {sup 14}C specific activity of ABA was always lower than those in xanthophylls, such as violaxanthin and lutein, regardless of {sup 12}CO{sub 2} chase periods. The ABA accumulation in green leaves was not affected by fluridone when plants were stressed once, but the {sup 14}C incorporation into ABA was inhibited to the same extent as those of xanthophylls. The incorporation of {sup 18}O into the ABA ring when violaxanthin was labeled by {sup 18}O in vivo via the violaxanthin cycle indicates that at least a portion of ABA was derived from {sup 18}O-labeled violaxanthin during water stress.

  10. Stress corrosion cracking of alloy 182 weld in a PWR water environment

    International Nuclear Information System (INIS)

    Lima, Luciana Iglesias Lourenco; Schvartzman, Monica Maria de Abreu Mendonca; Quinan, Marco Antonio Dutra; Soares, Antonio Edicleto Gomes; Piva, Stephano P.T.

    2011-01-01

    The weld used to connect two different metals is known as dissimilar metal welds (DMW). In the nuclear power plant, this weld is used to join stainless steel nipples to low alloy carbon steel components on the nuclear pressurized water reactor (PWR). In most cases, nickel alloys are used to joint these materials. These alloys are known to accommodate the differences in composition and thermal expansion of the two materials. The stress corrosion cracking (SCC) is a phenomenon that occurs in nuclear power plants metallic components where susceptibility materials are subjected to the simultaneously effect of mechanical stress and an aggressive media with different compositions. SCC is one of degradation process that gradually introduces damage of components, change their characteristics with the operation time. The nickel alloy 600, and their weld metals (nickel alloys 82 and 182), originally selected due to its high corrosion resistance, it exhibit after long operation period (20 years), susceptibility to the SCC. This study presents a comparative work between the SCC in the Alloy 182 filler metal weld in two different temperatures (303 deg C and 325 deg C) in primary water. The susceptibility to stress corrosion cracking was assessed using the slow strain rate tensile (SSRT) test. The results of the SSRT tests indicated that SCC is a thermally-activated mechanism and that brittle fracture caused by the corrosion process was observed at 325 deg C. (author)

  11. Water relations and gas exchange in poplar and willow under water stress and elevated atmospheric CO2.

    Science.gov (United States)

    Johnson, Jon D; Tognetti, Roberto; Paris, Piero

    2002-05-01

    Predictions of shifts in rainfall patterns as atmospheric [CO2] increases could impact the growth of fast growing trees such as Populus spp. and Salix spp. and the interaction between elevated CO2 and water stress in these species is unknown. The objectives of this study were to characterize the responses to elevated CO2 and water stress in these two species, and to determine if elevated CO2 mitigated drought stress effects. Gas exchange, water potential components, whole plant transpiration and growth response to soil drying and recovery were assessed in hybrid poplar (clone 53-246) and willow (Salix sagitta) rooted cuttings growing in either ambient (350 &mgr;mol mol-1) or elevated (700 &mgr;mol mol-1) atmospheric CO2 concentration ([CO2]). Predawn water potential decreased with increasing water stress while midday water potentials remained unchanged (isohydric response). Turgor potentials at both predawn and midday increased in elevated [CO2], indicative of osmotic adjustment. Gas exchange was reduced by water stress while elevated [CO2] increased photosynthetic rates, reduced leaf conductance and nearly doubled instantaneous transpiration efficiency in both species. Dark respiration decreased in elevated [CO2] and water stress reduced Rd in the trees growing in ambient [CO2]. Willow had 56% lower whole plant hydraulic conductivity than poplar, and showed a 14% increase in elevated [CO2] while poplar was unresponsive. The physiological responses exhibited by poplar and willow to elevated [CO2] and water stress, singly, suggest that these species respond like other tree species. The interaction of [CO2] and water stress suggests that elevated [CO2] did mitigate the effects of water stress in willow, but not in poplar.

  12. Morphological plasticity of root growth under mild water stress increases water use efficiency without reducing yield in maize

    Science.gov (United States)

    Cai, Qian; Zhang, Yulong; Sun, Zhanxiang; Zheng, Jiaming; Bai, Wei; Zhang, Yue; Liu, Yang; Feng, Liangshan; Feng, Chen; Zhang, Zhe; Yang, Ning; Evers, Jochem B.; Zhang, Lizhen

    2017-08-01

    A large yield gap exists in rain-fed maize (Zea mays L.) production in semi-arid regions, mainly caused by frequent droughts halfway through the crop-growing period due to uneven distribution of rainfall. It is questionable whether irrigation systems are economically required in such a region since the total amount of rainfall does generally meet crop requirements. This study aimed to quantitatively determine the effects of water stress from jointing to grain filling on root and shoot growth and the consequences for maize grain yield, above- and below-ground dry matter, water uptake (WU) and water use efficiency (WUE). Pot experiments were conducted in 2014 and 2015 with a mobile rain shelter to achieve conditions of no, mild or severe water stress. Maize yield was not affected by mild water stress over 2 years, while severe stress reduced yield by 56 %. Both water stress levels decreased root biomass slightly but shoot biomass substantially. Mild water stress decreased root length but increased root diameter, resulting in no effect on root surface area. Due to the morphological plasticity in root growth and the increase in root / shoot ratio, WU under water stress was decreased, and overall WUE for both above-ground dry matter and grain yield increased. Our results demonstrate that an irrigation system might be not economically and ecologically necessary because the frequently occurring mild water stress did not reduce crop yield much. The study helps us to understand crop responses to water stress during a critical water-sensitive period (middle of the crop-growing season) and to mitigate drought risk in dry-land agriculture.

  13. Morphological plasticity of root growth under mild water stress increases water use efficiency without reducing yield in maize

    Directory of Open Access Journals (Sweden)

    Q. Cai

    2017-08-01

    Full Text Available A large yield gap exists in rain-fed maize (Zea mays L. production in semi-arid regions, mainly caused by frequent droughts halfway through the crop-growing period due to uneven distribution of rainfall. It is questionable whether irrigation systems are economically required in such a region since the total amount of rainfall does generally meet crop requirements. This study aimed to quantitatively determine the effects of water stress from jointing to grain filling on root and shoot growth and the consequences for maize grain yield, above- and below-ground dry matter, water uptake (WU and water use efficiency (WUE. Pot experiments were conducted in 2014 and 2015 with a mobile rain shelter to achieve conditions of no, mild or severe water stress. Maize yield was not affected by mild water stress over 2 years, while severe stress reduced yield by 56 %. Both water stress levels decreased root biomass slightly but shoot biomass substantially. Mild water stress decreased root length but increased root diameter, resulting in no effect on root surface area. Due to the morphological plasticity in root growth and the increase in root ∕ shoot ratio, WU under water stress was decreased, and overall WUE for both above-ground dry matter and grain yield increased. Our results demonstrate that an irrigation system might be not economically and ecologically necessary because the frequently occurring mild water stress did not reduce crop yield much. The study helps us to understand crop responses to water stress during a critical water-sensitive period (middle of the crop-growing season and to mitigate drought risk in dry-land agriculture.

  14. Ascorbic Acid Alleviates Water Stress in Young Peach Trees and Improves Their Performance after Rewatering

    Directory of Open Access Journals (Sweden)

    Consuelo Penella

    2017-09-01

    Full Text Available Exogenous application of biochemicals has been found to improve water stress tolerance in herbaceous crops but there are limited studies on deciduous fruit trees. The goal of this research was to study if ascorbic acid applications could improve physiological mechanisms associated with water stress tolerance in young fruit trees. Ascorbic acid was foliarly applied at a concentration of 250 ppm to water-stressed and well-watered peach trees (control of two cultivars (‘Scarletprince’ and ‘CaroTiger’. Trees received either one or two applications, and 1 week after the second application all trees were rewatered to field capacity. Upon rewatering, CO2 assimilation and stomatal conductance of water-stressed ‘Scarletprince’ trees sprayed with ascorbic acid (one or two applications were similar to those of well-irrigated trees, but water-stressed trees that had not received ascorbic acid did not recover photosynthetical functions. Also, water status in sprayed water-stressed ‘Scarletprince’ trees was improved to values similar to control trees. On the other hand, water-stressed ‘CaroTiger’ trees needed two applications of ascorbic acid to reach values of CO2 assimilation similar to control trees but these applications did not improve their water status. In general terms, different response mechanisms to cope with water stress in presence of ascorbic acid were found in each cultivar, with ‘Scarletprince’ trees preferentially using proline as compatible solute and ‘CaroTiger’ trees relying on stomatal regulation. The application of ascorbic acid reduced cell membrane damage and increased catalase activity in water-stressed trees of both cultivars. These results suggest that foliar applications of ascorbic acid could be used as a management practice for improving water stress tolerance of young trees under suboptimal water regimes.

  15. Ascorbic Acid Alleviates Water Stress in Young Peach Trees and Improves Their Performance after Rewatering.

    Science.gov (United States)

    Penella, Consuelo; Calatayud, Ángeles; Melgar, Juan C

    2017-01-01

    Exogenous application of biochemicals has been found to improve water stress tolerance in herbaceous crops but there are limited studies on deciduous fruit trees. The goal of this research was to study if ascorbic acid applications could improve physiological mechanisms associated with water stress tolerance in young fruit trees. Ascorbic acid was foliarly applied at a concentration of 250 ppm to water-stressed and well-watered peach trees (control) of two cultivars ('Scarletprince' and 'CaroTiger'). Trees received either one or two applications, and 1 week after the second application all trees were rewatered to field capacity. Upon rewatering, CO 2 assimilation and stomatal conductance of water-stressed 'Scarletprince' trees sprayed with ascorbic acid (one or two applications) were similar to those of well-irrigated trees, but water-stressed trees that had not received ascorbic acid did not recover photosynthetical functions. Also, water status in sprayed water-stressed 'Scarletprince' trees was improved to values similar to control trees. On the other hand, water-stressed 'CaroTiger' trees needed two applications of ascorbic acid to reach values of CO 2 assimilation similar to control trees but these applications did not improve their water status. In general terms, different response mechanisms to cope with water stress in presence of ascorbic acid were found in each cultivar, with 'Scarletprince' trees preferentially using proline as compatible solute and 'CaroTiger' trees relying on stomatal regulation. The application of ascorbic acid reduced cell membrane damage and increased catalase activity in water-stressed trees of both cultivars. These results suggest that foliar applications of ascorbic acid could be used as a management practice for improving water stress tolerance of young trees under suboptimal water regimes.

  16. Selecting activated carbon for water and wastewater treatability studies

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, W.; Chang, Q.G.; Liu, W.D.; Li, B.J.; Jiang, W.X.; Fu, L.J.; Ying, W.C. [East China University of Chemical Technology, Shanghai (China)

    2007-10-15

    A series of follow-up investigations were performed to produce data for improving the four-indicator carbon selection method that we developed to identify high-potential activated carbons effective for removing specific organic water pollutants. The carbon's pore structure and surface chemistry are dependent on the raw material and the activation process. Coconut carbons have relatively more small pores than large pores; coal and apricot nutshell/walnut shell fruit carbons have the desirable pore structures for removing adsorbates of all sizes. Chemical activation, excessive activation, and/or thermal reactivation enlarge small pores, resulting in reduced phenol number and higher tannic acid number. Activated carbon's phenol, iodine, methylene blue, and tannic acid numbers are convenient indicators of its surface area and pore volume of pore diameters < 10, 10-15, 15-28, and > 28 angstrom, respectively. The phenol number of a carbon is also a good indicator of its surface acidity of oxygen-containing organic functional groups that affect the adsorptive capacity for aromatic and other small polar organics. The tannic acid number is an indicator of carbon's capacity for large, high-molecular-weight natural organic precursors of disinfection by-products in water treatment. The experimental results for removing nitrobenzene, methyl-tert-butyl ether, 4,4-bisphenol, humic acid, and the organic constituents of a biologically treated coking-plant effluent have demonstrated the effectiveness of this capacity-indicator-based method of carbon selection.

  17. Performance evaluation of selected crop yield-water use models for wheat crop

    Directory of Open Access Journals (Sweden)

    H. E. Igbadun

    2001-10-01

    Full Text Available Crop yield-water use models that provide useful information about the exact form of crop response to different amounts of water used by the crop throughout its growth stages and those that provide adequate information for decisions on optimal use of water in the farm were evaluated. Three crop yield models: Jensen (1968, Minhas et al., (1974 and Bras and Cordova (1981 additive type models were studied. Wheat (Triticum aestivum was planted at the Institute for Agricultural Research Farm during the 1995/96 and 1996/97 irrigation seasons of November to March. The data collected from the field experiments during the 1995/96 planting season were used to calibrate the models and their stress sensitivity factors estimated for four selected growth stages of the wheat crop. The ability of the model to predict grain yield of wheat with the estimated stress sensitivity factors was evaluated by comparing predicted grain yields by each model with those obtained in the field during the 1996/97 season. The three models performed fairly well in predicting grain yields, as the predicted results were not significantly different from the field measured grain yield at 5% level of significance.

  18. Effects of complete water fasting and regeneration diet on kidney function, oxidative stress and antioxidants.

    Science.gov (United States)

    Mojto, V; Gvozdjakova, A; Kucharska, J; Rausova, Z; Vancova, O; Valuch, J

    2018-01-01

    The aim of the study was to observe the influence of 11-days complete water fasting (WF) and regeneration diet (RD) on renal function, body weight, blood pressure and oxidative stress. Therapeutic WF is considered a healing method. Ten volunteers drank only water for 11 days, followed by RD for the next 11 days. Data on body weight, blood pressure, kidney functions, antioxidants, lipid peroxidation, cholesterols, triacylglycerols and selected biochemical parameters were obtained. WF increased uric acid and creatinine and decreased glomerular filtration rate. After RD, the parameters were comparable to baseline values. Urea was not affected. Lipid peroxidation (TBARS) decreased and maintained stable after RD. Fasting decreased α-tocopherol and increased γ-tocopherol, no significant changes were found after RD. Coenzyme Q10 decreased after RD. HDL-cholesterol decreased in WF. Total- and LDL-cholesterol decreased after RD. Other biochemical parameters were within the range of reference values. The effect of the complete fasting on kidney function was manifested by hyperuricemia. Renal function was slightly decreased, however maintained within the reference values. After RD, it returned to baseline values. The positive effect of the complete water fasting was in the reduction of oxidative stress, body weight and blood pressure (Tab. 3, Ref. 25).

  19. Life-history responses of insects to water-deficit stress: a case study with the aphid Sitobion avenae.

    Science.gov (United States)

    Liu, Deguang; Dai, Peng; Li, Shirong; Ahmed, Syed Suhail; Shang, Zheming; Shi, Xiaoqin

    2018-05-29

    Drought may become one of the greatest challenges for cereal production under future warming scenarios, and its impact on insect pest outbreaks is still controversial. To address this issue, life-history responses of the English grain aphid, Sitobion avenae (Fabricius), from three areas of different drought levels were compared under three water treatments. Significant differences were identified in developmental time, fecundity and adult weight among S. avenae clones from moist, semiarid and arid areas under all the three water treatments. Semiarid and arid area clones tended to have higher heritability for test life-history traits than moist area clones. We identified significant selection of water-deficit on the developmental time of 1st instar nymphs and adult weight for both semiarid and arid area clones. The impact of intermediate and severe water-stress on S. avenae's fitness was neutral and negative (e.g., decreased fecundity and weight), respectively. Compared with arid-area clones, moist- and semiarid-area clones showed higher extents of adaptation to the water-deficit level of their respective source environment. Adult weight was identified as a good indicator for S. avenae's adaptation potential under different water-stress conditions. After their exposure to intermediate water-deficit stress for only five generations, adult weight and fecundity tended to decrease for moist- and semiarid-area clones, but increase for arid-area clones. It is evident from our study that S. avenae clones from moist, semiarid and arid areas have diverged under different water-deficit stress, and such divergence could have a genetic basis. The impact of drought on S. avenae's fitness showed a water-level dependent pattern. Clones of S. avenae were more likely to become adapted to intermediate water-deficit stress than severe water-deficit stress. After continuous water-deficit stress of only five generations, the adaptation potential of S. avenae tended to decrease for moist

  20. Catch the Best: Novel Screening Strategy to Select Stress Protecting Agents for Crop Plants

    Directory of Open Access Journals (Sweden)

    Christin Zachow

    2013-11-01

    Full Text Available Climate change increases stress levels for crops and affects the economic and environmental aspects of agricultural management systems. The application of stress tolerance-mediating microorganisms is an auspicious strategy for improving crop protection, and as such, we developed a direct selection strategy to obtain cultivable microorganisms from promising bioresources using the bait plants, maize, oilseed rape, sorghum and sugar beet. Alpine mosses, lichens and primrose were selected as bioresources, as each is adapted to adverse environmental conditions. A 10% crop-specific selection was found for bait plant rhizosphere communities using cultivation-independent fingerprints, and their potential role as stress protecting agents (SPA was evaluated following the cultivation of captured bacteria. In addition to assays identifying phytopathogen antagonism and plant growth promotion capacities, our evaluation included those that test the ability to allocate nutrients. Moreover, we developed new assays to measure tolerance in diverse stress conditions. A score scheme was applied to select SPAs with desired properties, and three Pseudomonas species with pronounced antagonistic activity that showed elevated tolerance to desiccation and an improved seed germination rate were subsequently chosen. Screening for environmentally-conditioned and host-adapted microorganisms provides a novel tool for target-oriented exploitation of microbial bioresources for the management of ecofriendly crops facing biotic and abiotic stresses.

  1. Selection of mutants tolerant of oxidative stress from respiratory cultures of Lactobacillus plantarum C17.

    Science.gov (United States)

    Zotta, T; Ianniello, R G; Guidone, A; Parente, E; Ricciardi, A

    2014-03-01

    Lactobacillus plantarum is a lactic acid bacterium involved in the production of many fermented foods. Recently, several studies have demonstrated that aerobic or respiratory metabolism in this species leads to improved technological and stress response properties. We investigated respiratory growth, metabolite production and stress resistance of Lact. plantarum C17 during batch, fed-batch and chemostat cultivations under respiratory conditions. Sixty mutants were selected for their ability to tolerate oxidative stress using H2 O2 and menadione as selective agents and further screened for their capability to growth under anaerobic, respiratory and oxidative stress conditions. Dilution rate clearly affected the physiological state of cells and, generally, slow-growing cultures had improved survival to stresses, catalase production and oxygen uptake. Most mutants were more competitive in terms of biomass production and ROS degradation compared with wild-type strain (wt) C17 and two of these (C17-m19 and C17-m58) were selected for further experiments. This work confirms that, in Lact. plantarum, respiration and low growth rates confer physiological and metabolic advantages compared with anaerobic cultivation. Our strategy of natural selection successfully provides a rapid and inexpensive screening for a large number of strains and represents a food-grade approach of practical relevance in the production of starter and probiotic cultures. © 2013 The Society for Applied Microbiology.

  2. SUNLIT AND SHADED MAIZE CANOPY WATER LOSS UNDER VARIED WATER STRESS

    Directory of Open Access Journals (Sweden)

    Antonio Odair Santos

    1999-12-01

    Full Text Available ABSTRACT The precise estimation of transpiration from plant canopies is important for the monitoring of crop water use and management of many agricultural operations related to water use planning. The aim of this study was to estimate transpiration from sunlit and shaded fractions of a maize ( Zea mays L. canopy, using the Penman-Monteith energy balance equation with modifications introduced by Fuchs et al. (1987 and Fuchs & Cohen (1989. Estimated values were validated by a heat pulse system, which was used to measure stem sap flow and by a weighing lysimeter. A relationship between incident radiation and leaf stomatal conductance for critical levels of leaf water potential was used to estimate transpiration. Results showed that computed transpiration of the shaded canopy ranged from 27 to 45% of the total transpiration when fluctuations in atmospheric demand and the level of water stress were taken in account. Hourly and daily estimates of transpiration showed agreement with lysimeter and heat pulse measurements on the well-watered plots. For the water-limited plots the precision of the estimate decreased due to difficulties in simulating the canopy stomatal conductance.

  3. Infrared thermometry and the crop water stress index. I. History, theory, and baselines

    International Nuclear Information System (INIS)

    Gardner, B.R.; Nielsen, D.C.; Shock, C.C.

    1992-01-01

    Development of portable infrared thermometers and the definition of the Crop Water Stress Index (CWSI) have led to widespread interest in infrared thermometry to monitor water stress and schedule irrigations. But the CWSI concept is still new and poorly understood by many. The purpose of this paper is to review the definition of CWSI, and the determination and interpretation of the non-water-stressed baselines used to compute CWSI. The non-water-stressed baseline equation normalizes the canopy minus air temperature differential for variations in vapor pressure deficit. Non-water-stressed baselines can be determined empirically from measurements of canopy and air temperatures and vapor pressure deficit, made diurnally on a single day, or at a single time of day over many days, on well-watered plants. The value of the maximum canopy minus air temperature differential under maximum water stress should also be determined empirically. Causes for CWSI values falling outside of the defined 0 to 10 unit range are reviewed. Non-water-stressed baselines may shift with plant growth stage. Effective use of CWSI is dependent on understanding the definition of CWSI, and the proper determination and use of non-water-stressed baselines. (author)

  4. Breeding approaches in simultaneous selection for multiple stress tolerance of maize in tropical environments

    Directory of Open Access Journals (Sweden)

    Denić M.

    2007-01-01

    Full Text Available Maize is the principal crop and major staple food in the most countries of Sub-Saharan Africa. However, due to the influence of abiotic and biotic stress factors, maize production faces serious constraints. Among the agro-ecological conditions, the main constraints are: lack and poor distribution of rainfall; low soil fertility; diseases (maize streak virus, downy mildew, leaf blights, rusts, gray leaf spot, stem/cob rots and pests (borers and storage pests. Among the socio-economic production constraints are: poor economy, serious shortage of trained manpower; insufficient management expertise, lack of use of improved varieties and poor cultivation practices. To develop desirable varieties, and thus consequently alleviate some of these constraints, appropriate breeding approaches and field-based methodologies in selection for multiple stress tolerance, were implemented. These approaches are mainly based on: a Crossing selected genotypes with more desirable stress tolerant and other agronomic traits; b Using the disease/pest spreader row method, combined with testing and selection of created progenies under strong to intermediate pressure of drought and low soil fertility in nurseries; and c Evaluation of the varieties developed in multi-location trials under low and "normal" inputs. These approaches provide testing and selection of large number of progenies, which is required for simultaneous selection for multiple stress tolerance. Data obtained revealed that remarkable improvement of the traits under selection was achieved. Biggest progress was obtained in selection for maize streak virus and downy mildew resistance, flintiness and earliness. In the case of drought stress, statistical analyses revealed significant negative correlation between yield and anthesis-silking interval, and between yield and days to silk, but positive correlation between yield and grain weight per ear.

  5. Maintenance of water uptake and reduced water loss contribute to water stress tolerance of Spiraea alba Du Roi and Spiraea tomentosa L.

    Science.gov (United States)

    Stanton, Kelly M; Mickelbart, Michael V

    2014-01-01

    Two primarily eastern US native shrubs, Spiraea alba Du Roi and Spiraea tomentosa L., are typically found growing in wet areas, often with standing water. Both species have potential for use in the landscape, but little is known of their environmental requirements, including their adaptation to water stress. Two geographic accessions of each species were evaluated for their response to water stress under greenhouse conditions. Above-ground biomass, water relations and gas exchange were measured in well-watered and water stress treatments. In both species, water stress resulted in reduced growth, transpiration and pre-dawn water potential. However, both species also exhibited the ability to osmotically adjust to lower soil water content, resulting in maintained midday leaf turgor potential in all accessions. Net CO2 assimilation was reduced only in one accession of S. alba, primarily due to large reductions in stomatal conductance. S. tomentosa lost a larger proportion of leaves than S. alba in response to water stress. The primary water stress tolerance strategies of S. alba and S. tomentosa appear to be the maintenance of water uptake and reduced water loss.

  6. Supercritical fluid extraction of selected pharmaceuticals from water and serum.

    Science.gov (United States)

    Simmons, B R; Stewart, J T

    1997-01-24

    Selected drugs from benzodiazepine, anabolic agent and non-steroidal anti-inflammatory drug (NSAID) therapeutic classes were extracted from water and serum using a supercritical CO2 mobile phase. The samples were extracted at a pump pressure of 329 MPa, an extraction chamber temperature of 45 degrees C, and a restrictor temperature of 60 degrees C. The static extraction time for all samples was 2.5 min and the dynamic extraction time ranged from 5 to 20 min. The analytes were collected in appropriate solvent traps and assayed by modified literature HPLC procedures. Analyte recoveries were calculated based on peak height measurements of extracted vs. unextracted analyte. The recovery of the benzodiazepines ranged from 80 to 98% in water and from 75 to 94% in serum. Anabolic drug recoveries from water and serum ranged from 67 to 100% and 70 to 100%, respectively. The NSAIDs were recovered from water in the 76 to 97% range and in the 76 to 100% range from serum. Accuracy, precision and endogenous peak interference, if any, were determined for blank and spiked serum extractions and compared with classical sample preparation techniques of liquid-liquid and solid-phase extraction reported in the literature. For the benzodiazepines, accuracy and precision for supercritical fluid extraction (SFE) ranged from 1.95 to 3.31 and 0.57 to 1.25%, respectively (n = 3). The SFE accuracy and precision data for the anabolic agents ranged from 4.03 to 7.84 and 0.66 to 2.78%, respectively (n = 3). The accuracy and precision data reported for the SFE of the NSAIDs ranged from 2.79 to 3.79 and 0.33 to 1.27%, respectively (n = 3). The precision of the SFE method from serum was shown to be comparable to the precision obtained with other classical preparation techniques.

  7. Modelling global water stress of the recent past: on the relative importance of trends in water demand and climate variability

    NARCIS (Netherlands)

    Wada, Y.; Beek, L.P.H. van; Bierkens, M.F.P.

    2011-01-01

    During the past decades, human water use has more than doubled, yet available freshwater resources are finite. As a result, water scarcity has been prevalent in various regions of the world. Here, we present the first global assessment of past development of water stress considering not only climate

  8. Ultraviolet-B and water stress effects on growth, gas exchange and oxidative stress in sunflower plants.

    Science.gov (United States)

    Cechin, Inês; Corniani, Natália; de Fátima Fumis, Terezinha; Cataneo, Ana Catarina

    2008-07-01

    The effects and interaction of drought and UV-B radiation were studied in sunflower plants (Helianthus annuus L. var. Catissol-01), growing in a greenhouse under natural photoperiod conditions. The plants received approximately 1.7 W m(-2) (controls) or 8.6 W m(-2) (+UV-B) of UV-B radiation for 7 h per day. The UV-B and water stress treatments started 18 days after sowing. After a period of 12 days of stress, half of the water-stressed plants (including both UV-B irradiated or non-irradiated) were rehydrated. Both drought and UV-B radiation treatments resulted in lower shoot dry matter per plant, but there was no significant interaction between the two treatments. Water stress and UV-B radiation reduced photosynthesis, stomatal conductance and transpiration. However, the amplitude of the effects of both stressors was dependent on the interactions. This resulted in alleviation of the negative effect of drought on photosynthesis and transpiration by UV-B radiation as the water stress intensified. Intercelluar CO(2) concentration was initially reduced in all treatments compared to control plants but it increased with time. Photosynthetic pigments were not affected by UV-B radiation. Water stress reduced photosynthetic pigments only under high UV-B radiation. The decrease was more accentuated for chlorophyll a than for chlorophyll b. As a measure for the maximum efficiency of photosystem II in darkness F (v)/F (m) was used, which was not affected by drought stress but initially reduced by UV-B radiation. Independent of water supply, UV-B radiation increased the activity of pirogalol peroxidase and did not increase the level of malondialdehyde. On the other hand, water stress did not alter the activity of pirogalol peroxidase and caused membrane damage as assessed by lipid peroxidation. The application of UV-B radiation together with drought seemed to have a protective effect by lowering the intensity of lipid peroxidation caused by water stress. The content of proline

  9. Bread wheat selection against abiotic and biotic stresses in highland Balochistan, Pakistan

    International Nuclear Information System (INIS)

    Begum, I.; Afzal, J.; Afzal, J.

    2008-01-01

    Bread wheat (Triticum aestivum L. ssp. aestivum) lines were screened in multi-location trials in highland Balochistan, Pakistan from 1982 (F2) to 1990 (fixed lines). Objective of the study was to select and evaluate desirable genotypes for winter planting, Of 816 entries, only four successfully passed through the observation nurseries and yield trials. After nine years of testing only genotype ICW81.1471 was selected for wide-scale agronomic testing. Although the yield potential of this genotype was not significantly higher than that of the local check, it had the important advantage of possessing good resistance to yellow rust (Puccinia striiformis West) The results showed that exposure of segregating population to the prevailing environmental stresses of cold and drought was an effective selection procedure for identifying genotypes which are resistant to such stresses. Effective selection can be made for other desirable attributes such as disease and pest resistance, plant height and time to maturity. (author)

  10. Short-term spatial memory responses in aged Japanese quail selected for divergent adrenocortical stress responsiveness.

    Science.gov (United States)

    Suhr, C L; Schmidt, J B; Treese, S T; Satterlee, D G

    2010-04-01

    Stress-induced glucocorticoids can dampen learning and spatial memory via neuronal damage to the hippocampus. Cognition losses can be transient (associated with acute stress episodes) or permanent as in aged individuals who show chronic glucocorticoid-induced accelerated brain aging and neurodegeneration (dementia). Thus, chronic versus acute stress effects on spatial memory responses of quail selected for reduced (low stress, LS) or exaggerated (high stress, HS) plasma corticosterone (B) response to brief restraint were assessed. Aged food-motivated male LS and HS quail were tested for 10 min in a feed-baited 8-arm radial arm maze (RAM) 1) at 255 d of age (quail who had experienced lifelong management stressors but who were otherwise never intentionally stressed; that is, chronically stressed birds), 2) on the next day post-acute stressor treatment (5 min of restraint), and 3) on the next day without treatment (acute stress recovery). The RAM tests used the win-shift procedure in which visited arms were not rebaited. Radial arm maze performance was measured by determination of the total number of arm choices made, the number of correct entries made into baited arms out of the first 8 choices, the time required to make a choice, and the number of pellets eaten. Line effects (P LS), and number of pellets eaten (HS RAM testing nor its interaction with line further influenced these variables. Thus, although selection for divergent plasma B responsiveness to an acute stressor was found to be associated with severe impairment of spatial memory in aged male HS compared with LS quail, the observed spatial memory impairments (HS > LS) could not be further altered by acute stressor treatment. Line differences in cognition may reflect lifelong management-induced stress episodes that periodically produce higher plasma B responses in HS than LS quail, which underlie HS quail memory deficits, or other etiologies, or both.

  11. Estimating anthropogenic ecological water stress in the US great lakes region

    Science.gov (United States)

    Anthropocentric water resources management that prioritizes socio-economic growth can cause harmful ecological water stress by depriving aquatic ecosystems of the water needed to sustain habitats. It is important to better understand the impacts of water withdrawal by different economic sectors (e.g...

  12. Spinach biomass yield and physiological response to interactive salinity and water stress

    Science.gov (United States)

    Critical shortages of fresh water throughout arid regions means that growers must face the choice of applying insufficient fresh water, applying saline water, or consider the option of combined water and salt stress. The best approach to manage drought and salinity is evaluation of the impact of wat...

  13. Selected bibliography on heavy water, tritiated water and hydrogen isotopes (1981-1992)

    International Nuclear Information System (INIS)

    Gopalakrishnan, V.T.; Sutawane, U.B.; Rathi, B.N.

    1994-01-01

    A selected bibliography on heavy water, tritiated water and hydrogen isotopes is presented. This bibliography covers the period 1981-1992 and is in continuation to Division's earlier report BARC-1192 (1983). The sources of information for this compilation are Chemical Abstracts, INIS Atom Index and also some scattered search through journals and reports available in our library. No claim is made towards exhaustiveness of this bibliography even though sincere attempts have been made for a wide coverage. The bibliography is arranged under the headings: (1) production, purification, recovery, reprocessing and storage, (2) isotope exchange, 3) isotope analysis, (4) properties and (5) miscellaneous. Total number of references in the bibliography are 1762. (author)

  14. Modelling global water stress of the recent past: on the relative importance of trends in water demand and climate variability

    Science.gov (United States)

    Wada, Y.; van Beek, L. P. H.; Bierkens, M. F. P.

    2011-12-01

    During the past decades, human water use has more than doubled, yet available freshwater resources are finite. As a result, water scarcity has been prevalent in various regions of the world. Here, we present the first global assessment of past development of water stress considering not only climate variability but also growing water demand, desalinated water use and non-renewable groundwater abstraction over the period 1960-2001 at a spatial resolution of 0.5°. Agricultural water demand is estimated based on past extents of irrigated areas and livestock densities. We approximate past economic development based on GDP, energy and household consumption and electricity production, which are subsequently used together with population numbers to estimate industrial and domestic water demand. Climate variability is expressed by simulated blue water availability defined by freshwater in rivers, lakes, wetlands and reservoirs by means of the global hydrological model PCR-GLOBWB. We thus define blue water stress by comparing blue water availability with corresponding net total blue water demand by means of the commonly used, Water Scarcity Index. The results show a drastic increase in the global population living under water-stressed conditions (i.e. moderate to high water stress) due to growing water demand, primarily for irrigation, which has more than doubled from 1708/818 to 3708/1832 km3 yr-1 (gross/net) over the period 1960-2000. We estimate that 800 million people or 27% of the global population were living under water-stressed conditions for 1960. This number is eventually increased to 2.6 billion or 43% for 2000. Our results indicate that increased water demand is a decisive factor for heightened water stress in various regions such as India and North China, enhancing the intensity of water stress up to 200%, while climate variability is often a main determinant of extreme events. However, our results also suggest that in several emerging and developing economies

  15. Chlorine dioxide reaction with selected amino acids in water

    International Nuclear Information System (INIS)

    Navalon, Sergio; Alvaro, Mercedes; Garcia, Hermenegildo

    2009-01-01

    Chlorine dioxide is a hypochlorite alternative disinfectant agent. In this context, we have determined the products formed in the reaction of ClO 2 with selected amino acids as model compounds that can be present in natural waters. The reaction of tryptophane, histidine and tyrosine (10 ppm each) with ClO 2 were studied at molar ratios ranging from 0.25 to 4 in the presence or absence of oxygen. It was found that in the absence of oxygen adding substoichiometric amounts of ClO 2 creates products that are structurally similar to the starting amino acids. Through a series of cascade reactions the initial product distribution gradually evolves toward simple, small carbon chain products that are far from the starting amino acid. The reaction product distribution revealed that chlorine dioxide can attack the electron-rich aromatic moieties as well as the nitrogen atom lone electron pair. Our study is relevant to gain knowledge on the reaction mechanism of ClO 2 with ubiquitous amino acids present in natural waters.

  16. Selection criteria for wastewater treatment technologies to protect drinking water.

    Science.gov (United States)

    von Sperling, M

    2000-01-01

    The protection of water bodies used as sources for drinking water is intimately linked to the adoption of adequate technologies for the treatment of the wastewater generated in the catchment area. The paper presents a general overview of the main technologies used for the treatment of domestic sewage, with a special emphasis on developing countries, and focussing on the main parameters of interest, such as BOD, coliforms and nutrients. A series of tables, figures and charts that can be used for the preliminary selection of treatment technologies is presented. The systems analysed are: stabilisation ponds, activated sludge, trickling filters, anaerobic systems and land disposal. Within each system, the main process variants are covered. Two summary tables are presented, one for quantitative analysis, including easily usable information based on per capita values (US$/cap, Watts/cap, m2 area/cap, m3 sludge/cap), and another for a qualitative comparison among the technologies, based on a one-to-five-star scoring system. The recent trend in tropical countries in the use of UASB (Upflow Anaerobic Sludge Blanket) reactors is also discussed.

  17. Nitrogen accumulation in lucerne (Medicago sativa L. under water deficit stress

    Directory of Open Access Journals (Sweden)

    Vasileva Viliana

    2013-01-01

    Full Text Available In order to study nitrogen accumulation in aboveground and root dry mass in lucerne (Medicago sativa L. under water deficit stress, a pot experiment was carried out at the Institute of Forage Crops, Pleven, Bulgaria. The plants were grown under optimum water supply (75-80% FC and 10-days water deficit stress was simulated at the stage of budding by interrupting the irrigation until soil moisture was reduced to 37-40% FC. Mineral nitrogen fertilization (ammonium nitrate at the doses of 40, 80, 120 and 160 mg N kg-1 soil was applied. It was found that nitrogen accumulation in dry aboveground mass was reduced to 18.0%, and in dry root mass to 26.5% under water deficit stress. Mineral nitrogen fertilization contributed to easily overcome the stress conditions of water deficit stress in lucerne.

  18. Germination sensitivity to water stress in four shrubby species across the Mediterranean Basin.

    Science.gov (United States)

    Chamorro, D; Luna, B; Ourcival, J-M; Kavgacı, A; Sirca, C; Mouillot, F; Arianoutsou, M; Moreno, J M

    2017-01-01

    Mediterranean shrublands are generally water-limited and fire-driven ecosystems. Seed-based post-fire regeneration may be affected by varying rainfall patterns, depending on species sensitivity to germinate under water stress. In our study, we considered the germination response to water stress in four species from several sites across the Mediterranean Basin. Seeds of species with a hard coat (Cistus monspeliensis, C. salviifolius, Cistaceae, Calicotome villosa, Fabaceae) or soft coat (Erica arborea, Ericaceae), which were exposed or not to a heat shock and smoke (fire cues), were made to germinate under water stress. Final germination percentage, germination speed and viability of seeds were recorded. Germination was modelled using hydrotime analysis and correlated to the water balance characteristics of seed provenance. Water stress was found to decrease final germination in the three hard-seeded species, as well as reduce germination speed. Moreover, an interaction between fire cues and water stress was found, whereby fire cues increased sensitivity to water stress. Seed viability after germination under water stress also declined in two hard-seeded species. Conversely, E. arborea showed little sensitivity to water stress, independent of fire cues. Germination responses varied among populations of all species, and hydrotime parameters were not correlated to site water balance, except in E. arborea when not exposed to fire cues. In conclusion, the species studied differed in germination sensitivity to water stress; furthermore, fire cues increased this sensitivity in the three hard-seeded species, but not in E. arborea. Moreover, populations within species consistently differed among themselves, but these differences could only be related to the provenance locality in E. arborea in seeds not exposed to fire cues. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

  19. Paraheliotropism can protect water-stressed bean (Phaseolus vulgaris L.) plants against photoinhibition.

    Science.gov (United States)

    Pastenes, Claudio; Porter, Victor; Baginsky, Cecilia; Horton, Peter; González, Javiera

    2004-12-01

    In order to estimate the importance of leaf movements on photosynthesis in well-watered and water-stressed field grown bean cultivars (Arroz Tuscola (AT), Orfeo INIA (OI), Bayos Titan (BT), and Hallados Dorado (HD)), CO2 assimilation, leaf temperature, and capacity for the maximum quantum yield recovery, measured as Fv/Fm, were assessed. Leaf water potential was lower in water-stressed compared to control plants throughout the day. Water status determined a decrease in the CO2 assimilation and stomatal conductance as light intensity and temperature increased up to maximal intensities at midday. Both parameters were lower in stressed compared to control plants. Even though high light intensity and water-stress induced stomatal closure is regarded as a photoinhibitory condition, the recovery of variable to maximal fluorescence (Fv/Fm) after 30min of darkness was nearly constant in both water regimes. In fact, higher values were observed in OI and AT when under stress. Photochemical and non-photochemical fluorescence quenching resulted in minor changes during the day and were similar between watered and stressed plants. It is concluded that paraheliotropism, present in the four bean cultivars, efficiently protects stressed plants from photoinhibition in the field and helps maintain leaf temperatures far below the ambient temperatures, however, it may also be responsible for low CO2 assimilation rates in watered plants.

  20. Temp-to-permanent employees: a longitudinal study of stress and selection success.

    Science.gov (United States)

    Bauer, T N; Truxillo, D M

    2000-07-01

    Temp-to-permanent employees are temporary workers who have the opportunity to become permanent employees after a specific amount of time (e.g., generally after a 3- to 12-month period of trial work). The authors predicted that temporary worker individual differences, self-monitoring, tolerance for ambiguity, and role adjustment are related to temporary worker physiological stress and to whether temporary employees are offered permanent employment. Longitudinal data collection (pre- and postentry) resulted in data from 136 temp-to-permanent employees. Tolerance for ambiguity and role adjustment were found to be related to temporary worker stress and selection success. Self-monitoring was related to selection success for workers in an extended probationary period. These results suggest the need for further exploration and application of models of stress in understanding factors related to temporary worker success.

  1. Interaction of callus selection media and stress duration for in vitro ...

    African Journals Online (AJOL)

    Callus culture is a novel approach addressing cultured cells as selection units independent of whole plant. Natural variations for drought tolerance existing among cell lines can be exploited in vitro in the presence of suitable concentration of osmoticum and stress duration. The study was aimed to standardized callus ...

  2. Selection for resistance to white pine blister rust affects the abiotic stress tolerances of limber pine

    Science.gov (United States)

    Patrick J. Vogan; Anna W. Schoettle

    2015-01-01

    Limber pine (Pinus flexilis) mortality is increasing across the West as a result of the combined stresses of white pine blister rust (Cronartium ribicola; WPBR), mountain pine beetle (Dendroctonus ponderosae), and dwarf mistletoe (Arceuthobium cyanocarpum) in a changing climate. With the continued spread of WPBR, extensive mortality will continue with strong selection...

  3. Electrochemical potential measurements in boiling water reactors; relation to water chemistry and stress corrosion

    International Nuclear Information System (INIS)

    Indig, M.E.; Cowan, R.L.

    1981-01-01

    Electrochemical potential measurements were performed in operating boiling water reactors to determine the range of corrosion potentials that exist from cold standby to full power operation and the relationship of these measurements to reactor water chemistry. Once the corrosion potentials were known, experiments were performed in the laboratory under electrochemical control to determine potentials and equivalent dissolved oxygen concentrations where intergranular stress corrosion cracking (IGSCC) would and would not occur on welded Type-304 stainless steel. At 274 0 C, cracking occurred at potentials that were equivalent to dissolved oxygen concentration > 40 to 50 ppb. With decreasing temperature, IGSCC became more difficult and only severely sensitized stainless steel would crack. Recent in-reactor experiments combined with the previous laboratory data, have shown that injection of small concentrations of hydrogen during reactor operation can cause a significant decrease in corrosion potential which should cause immunity to IGSCC. (author)

  4. Modified Feddes type stress reduction function for modeling root water uptake: Accounting for limited aeration and low water potential

    Science.gov (United States)

    Peters, Andre; Durner, Wolfgang; Iden, Sascha C.

    2017-04-01

    Modeling water flow in the soil-plant-atmosphere continuum with the Richards equation requires a model for the sink term describing water uptake by plant roots. Despite recent progress in developing process-based models of water uptake by plant roots and water flow in aboveground parts of vegetation, effective models of root water uptake are widely applied and necessary for large-scale applications. Modeling root water uptake consists of three steps, (i) specification of the spatial distribution of potential uptake, (ii) reduction of uptake due to various stress sources, and (iii) enhancement of uptake in part of the simulation domain to describe compensation. We discuss the conceptual shortcomings of the frequently used root water uptake model of Feddes and suggest a simple but effective improvement of the model. The improved model parametrizes water stress in wet soil by a reduction scheme which is formulated as function of air content where water stress due to low soil water potential is described by the original approach of Feddes. The improved model is physically more consistent than Feddes' model because water uptake in wet soil is limited by aeration which is a function of water content. The suggested modification is particularly relevant for simulations in heterogeneous soils, because stress parameters are uniquely defined for the entire simulation domain, irrespective of soil texture. Numerical simulations of water flow and root water uptake in homogeneous and stochastic heterogeneous soils illustrate the effect of the new model on root water uptake and actual transpiration. For homogeneous fine-textured soils, root water uptake never achieves its potential rate. In stochastic heterogeneous soil, water uptake is more pronounced at the interfaces between fine and coarse regions which has potential implications for plant growth, nutrient uptake and depletion.

  5. Physiological behaviors and recovery responses of four Galician grapevine (Vitis vinifera L. ) cultivars under water stress

    OpenAIRE

    Islam, M.; Berrios, J.

    2012-01-01

    Gas exchange parameters and chlorophyll fluorescence of four pot grown Galician grapevines (Vitis vinifera L. cv. Albariño, Brancellao, Godello and Treixadura) were examined under different levels of water stress in greenhouse. After extreme stress, gas exchange recovery responses were evaluated. Average ΨPD for control and stressed plants were -0.4MPa and -1.45MPa respectively. All varieties showed gradual declining of all gas exchange parameters (gs, E and A) with increasing of stress perio...

  6. RESIDUAL STRESS MEASUREMENTS AND STRUCTURAL INTEGRITY IMPLICATIONS FOR SELECTIVE LASER MELTED TI-6AL-4V

    Directory of Open Access Journals (Sweden)

    Knowles, C. R.

    2012-11-01

    Full Text Available Selective laser melting (SLM of Ti-6Al-4V has significant potential in the aerospace and biotechnology industries. SLM employs a focused laser beam to melt successive layers of metallic powder into complex components. This process can result in the generation of high thermally-induced residual stresses. These residual stresses, together with micro-flaws/ pores from the inherent fabrication process, may lead to premature fatigue crack initiation and propagation at relatively low cyclic stresses. The hole-drilling strain gauge method was used to evaluate residual stresses within SLM Ti-6Al-4V specimens, with the intention of understanding the associated mechanisms for the successful application of SLM Ti-6Al-4V in industry.

  7. Stochastic weather inputs for improved urban water demand forecasting: application of nonlinear input variable selection and machine learning methods

    Science.gov (United States)

    Quilty, J.; Adamowski, J. F.

    2015-12-01

    Urban water supply systems are often stressed during seasonal outdoor water use as water demands related to the climate are variable in nature making it difficult to optimize the operation of the water supply system. Urban water demand forecasts (UWD) failing to include meteorological conditions as inputs to the forecast model may produce poor forecasts as they cannot account for the increase/decrease in demand related to meteorological conditions. Meteorological records stochastically simulated into the future can be used as inputs to data-driven UWD forecasts generally resulting in improved forecast accuracy. This study aims to produce data-driven UWD forecasts for two different Canadian water utilities (Montreal and Victoria) using machine learning methods by first selecting historical UWD and meteorological records derived from a stochastic weather generator using nonlinear input variable selection. The nonlinear input variable selection methods considered in this work are derived from the concept of conditional mutual information, a nonlinear dependency measure based on (multivariate) probability density functions and accounts for relevancy, conditional relevancy, and redundancy from a potential set of input variables. The results of our study indicate that stochastic weather inputs can improve UWD forecast accuracy for the two sites considered in this work. Nonlinear input variable selection is suggested as a means to identify which meteorological conditions should be utilized in the forecast.

  8. Water avoidance stress induces frequency through cyclooxygenase-2 expression: a bladder rat model.

    Science.gov (United States)

    Yamamoto, Keisuke; Takao, Tetsuya; Nakayama, Jiro; Kiuchi, Hiroshi; Okuda, Hidenobu; Fukuhara, Shinichiro; Yoshioka, Iwao; Matsuoka, Yasuhiro; Miyagawa, Yasushi; Tsujimura, Akira; Nonomura, Norio

    2012-02-01

    Water avoidance stress is a potent psychological stressor and it is associated with visceral hyperalgesia, which shows degeneration of the urothelial layer mimicking interstitial cystitis. Cyclooxygenase-2 inhibitors have been recognized to ameliorate frequency both in clinical and experimental settings. We investigated the voiding pattern and cyclooxygenase-2 expression in a rat bladder model of water avoidance stress. After being subjected to water avoidance stress or a sham procedure, rats underwent metabolic cage analysis and cystometrography. Real time reverse transcription polymerase chain reaction was carried out to examine cyclooxygenase-2 messenger ribonucleic acid in bladders of rats. Protein expression of cyclooxygenase-2 was analyzed with immunohistochemistry and western blotting. Furthermore, the effects of the cyclooxygenase-2 inhibitor, etodolac, were investigated by carrying out cystometrography, immunohistochemistry and western blotting. Metabolic cage analysis and cystometrography showed significantly shorter intervals and less volume of voiding in water avoidance stress rats. Significantly higher expression of cyclooxygenase-2 messenger ribonucleic acid was verified by reverse transcription polymerase chain reaction. Immunohistochemistry and western blotting showed significantly higher cyclooxygenase-2 protein levels in water avoidance stress bladders. Furthermore, immunohistochemistry showed high cyclooxygenase-2 expression exclusively in smooth muscle cells. All water avoidance stress-induced changes were reduced by cyclooxygenase-2 inhibitor pretreatment. Chronic stress might cause frequency through cyclooxygenase-2 gene upregulation in bladder smooth muscle cells. Further study of cyclooxygenase-2 in the water avoidance stress bladder might provide novel therapeutic modalities for interstitial cystitis. © 2011 The Japanese Urological Association.

  9. Stress corrosion cracking susceptibility of austenitic stainless steels in supercritical water conditions

    International Nuclear Information System (INIS)

    Novotny, R.; Haehner, P.; Ripplinger, S.; Siegl, J.; Penttilae, Sami; Toivonen, Aki

    2009-01-01

    Within the 6th Framework Program HPLWR-2 project (High Performance Light Water Reactor - Phase 2), stress corrosion cracking (SCC) susceptibilities of selected austenitic stainless steels, 316L and 316NG, were studied in supercritical water (SCW) with the aim to identify and describe the specific failure mechanisms prevailing during slow strain-rate tensile (SSRT) tests in ultra-pure demineralised SCW water solution. The SSRT tests were performed using a step-motor controlled loading device in an autoclave at 350 deg. C, 500 deg. C and 550 deg. C. Besides water temperature, the pressure, the oxygen content and the strain rate (resp. crosshead speed) were varied in the series of tests. The specimens SSRT tested to failure were subjected to fractographic analysis, in order to characterise the failure mechanisms. The fractography confirmed that failure was due to a combination of transgranular SCC and transgranular ductile fracture. The share of SCC and ductile fracture in the failure process of individual specimens was affected by the parameters of the SSRT tests, so that the environmental influence on SCC susceptibility could be assessed, in particular, the SCC sensitising effects of increasing oxygen content, decreasing strain rate and increasing test temperature. (author)

  10. Stress, Time Pressure, Strategy Selection and Math Anxiety in Mathematics: A Review of the Literature.

    Science.gov (United States)

    Caviola, Sara; Carey, Emma; Mammarella, Irene C; Szucs, Denes

    2017-01-01

    We review how stress induction, time pressure manipulations and math anxiety can interfere with or modulate selection of problem-solving strategies (henceforth "strategy selection") in arithmetical tasks. Nineteen relevant articles were identified, which contain references to strategy selection and time limit (or time manipulations), with some also discussing emotional aspects in mathematical outcomes. Few of these take cognitive processes such as working memory or executive functions into consideration. We conclude that due to the sparsity of available literature our questions can only be partially answered and currently there is not much evidence of clear associations. We identify major gaps in knowledge and raise a series of open questions to guide further research.

  11. Stress-physiological reactions of the green alga Scenedesmus opoliensis to water pollution with herbicides

    Directory of Open Access Journals (Sweden)

    Zsolt Gyula KERESZTES

    2009-05-01

    Full Text Available The freshwater green alga Scenedesmus opoliensis proves to be a suitable bioindicator of water pollution with different herbicides. One of the best molecular markers of stress condition imposed by herbicides is overproduction of malondialdehyde resulting from lipid peroxidation in the damaged membranes. Methylviologen, a largely used pre-emergence herbicide which generates reactive oxygen species in the illuminated chloroplasts, triggers the accumulation of ascorbic acid and enhances the enzymatic activity of catalase, both of these substances being involved in the antioxidative protection of algal cells. Diuron, a herbicide that inhibits photosynthetic electron transport on the acceptor side of photosystem II, causes a decline in oxygen production and in biomass accumulation of algae. Glufosinate induces accumulation of toxic ammonia and leads to enhanced net oxygen production, associated with a low rate of carbon assimilation. Long-term exposure to micromolar concentrations of herbicides results in significant changes in the rate of cell division, in hotosynthetic parameters and in the intensity of antioxidative defense. A proper bioindication of toxic effects of herbicides on algae requires a selected combination of different physiological and biochemical parameters which reflect the degree of stress exerted on living organisms by water pollution with xenobiotic organic compounds.

  12. Silicon improves seed germination and alleviates oxidative stress of bud seedlings in tomato under water deficit stress.

    Science.gov (United States)

    Shi, Yu; Zhang, Yi; Yao, Hejin; Wu, Jiawen; Sun, Hao; Gong, Haijun

    2014-05-01

    The beneficial effects of silicon on plant growth and development under drought have been widely reported. However, little information is available on the effects of silicon on seed germination under drought. In this work, the effects of exogenous silicon (0.5 mM) on the seed germination and tolerance performance of tomato (Solanum lycopersicum L.) bud seedlings under water deficit stress simulated by 10% (w/v) polyethylene glycol (PEG-6000) were investigated in four cultivars ('Jinpengchaoguan', 'Zhongza No.9', 'Houpi L402' and 'Oubao318'). The results showed that the seed germination percentage was notably decreased in the four cultivars under water stress, and it was significantly improved by added silicon. Compared with the non-silicon treatment, silicon addition increased the activities of superoxide dismutase (SOD) and catalase (CAT), and decreased the production of superoxide anion (O2·) and hydrogen peroxide (H2O2) in the radicles of bud seedlings under water stress. Addition of silicon decreased the total phenol concentrations in radicles under water stress, which might contribute to the decrease of peroxidase (POD) activity, as observed in the in vivo and in vitro experiments. The decrease of POD activity might contribute to a less accumulation of hydroxyl radical (·OH) under water stress. Silicon addition also decreased the concentrations of malondialdehyde (MDA) in the radicles under stress, indicating decreased lipid peroxidation. These results suggest that exogenous silicon could improve seed germination and alleviate oxidative stress to bud seedling of tomato by enhancing antioxidant defense. The positive effects of silicon observed in a silicon-excluder also suggest the active involvement of silicon in biochemical processes in plants. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  13. Residual stress improved by water jet peening using cavitation for small-diameter pipe inner surfaces

    International Nuclear Information System (INIS)

    Yasuo, Nakamura; Toshizo, Ohya; Koji, Okimura

    2001-01-01

    As one of degradation conditions on components used in water, the overlapping effect of environment, material and stress might cause stress corrosion cracking (SCC). Especially, for the tensile residual stress produced by welding, it is particularly effective to reduce the tensile residual stress on the material surface to prevent SCC. In this paper, the residual stress improvement method using cavitation impact generated by a water jet, called Water Jet Peening (WJP), has been developed as the maintenance technology for the inner surfaces of small-diameter Ni-Cr-Fe alloy (Alloy 600) pipes. As the results, by WJP for the inner surface of Alloy 600 pipe (inner diameter; approximately 10-15 mm), we confirmed that the compressive stress generated within the range from the surface to the inner part about 0.5 mm deep and took a maximum value about 350 MPa on the surface. (author)

  14. Acute stress induces selective alterations in cost/benefit decision-making.

    Science.gov (United States)

    Shafiei, Naghmeh; Gray, Megan; Viau, Victor; Floresco, Stan B

    2012-09-01

    Acute stress can exert beneficial or detrimental effects on different forms of cognition. In the present study, we assessed the effects of acute restraint stress on different forms of cost/benefit decision-making, and some of the hormonal and neurochemical mechanisms that may underlie these effects. Effort-based decision-making was assessed where rats chose between a low effort/reward (1 press=2 pellets) or high effort/reward option (4 pellets), with the effort requirement increasing over 4 blocks of trials (2, 5, 10, and 20 lever presses). Restraint stress for 1 h decreased preference for the more costly reward and induced longer choice latencies. Control experiments revealed that the effects on decision-making were not mediated by general reductions in motivation or preference for larger rewards. In contrast, acute stress did not affect delay-discounting, when rats chose between a small/immediate vs larger/delayed reward. The effects of stress on decision-making were not mimicked by treatment with physiological doses of corticosterone (1-3 mg/kg). Blockade of dopamine receptors with flupenthixol (0.25 mg/kg) before restraint did not attenuate stress-induced effects on effort-related choice, but abolished effects on choice latencies. These data suggest that acute stress interferes somewhat selectively with cost/benefit evaluations concerning effort costs. These effects do not appear to be mediated solely by enhanced glucocorticoid activity, whereas dopaminergic activation may contribute to increased deliberation times induced by stress. These findings may provide insight into impairments in decision-making and anergia associated with stress-related disorders, such as depression.

  15. Cereal Crop Proteomics: Systemic Analysis of Crop Drought Stress Responses Towards Marker-Assisted Selection Breeding

    Directory of Open Access Journals (Sweden)

    Arindam Ghatak

    2017-06-01

    Full Text Available Sustainable crop production is the major challenge in the current global climate change scenario. Drought stress is one of the most critical abiotic factors which negatively impact crop productivity. In recent years, knowledge about molecular regulation has been generated to understand drought stress responses. For example, information obtained by transcriptome analysis has enhanced our knowledge and facilitated the identification of candidate genes which can be utilized for plant breeding. On the other hand, it becomes more and more evident that the translational and post-translational machinery plays a major role in stress adaptation, especially for immediate molecular processes during stress adaptation. Therefore, it is essential to measure protein levels and post-translational protein modifications to reveal information about stress inducible signal perception and transduction, translational activity and induced protein levels. This information cannot be revealed by genomic or transcriptomic analysis. Eventually, these processes will provide more direct insight into stress perception then genetic markers and might build a complementary basis for future marker-assisted selection of drought resistance. In this review, we survey the role of proteomic studies to illustrate their applications in crop stress adaptation analysis with respect to productivity. Cereal crops such as wheat, rice, maize, barley, sorghum and pearl millet are discussed in detail. We provide a comprehensive and comparative overview of all detected protein changes involved in drought stress in these crops and have summarized existing knowledge into a proposed scheme of drought response. Based on a recent proteome study of pearl millet under drought stress we compare our findings with wheat proteomes and another recent study which defined genetic marker in pearl millet.

  16. Acute Stress Induces Selective Alterations in Cost/Benefit Decision-Making

    Science.gov (United States)

    Shafiei, Naghmeh; Gray, Megan; Viau, Victor; Floresco, Stan B

    2012-01-01

    Acute stress can exert beneficial or detrimental effects on different forms of cognition. In the present study, we assessed the effects of acute restraint stress on different forms of cost/benefit decision-making, and some of the hormonal and neurochemical mechanisms that may underlie these effects. Effort-based decision-making was assessed where rats chose between a low effort/reward (1 press=2 pellets) or high effort/reward option (4 pellets), with the effort requirement increasing over 4 blocks of trials (2, 5, 10, and 20 lever presses). Restraint stress for 1 h decreased preference for the more costly reward and induced longer choice latencies. Control experiments revealed that the effects on decision-making were not mediated by general reductions in motivation or preference for larger rewards. In contrast, acute stress did not affect delay-discounting, when rats chose between a small/immediate vs larger/delayed reward. The effects of stress on decision-making were not mimicked by treatment with physiological doses of corticosterone (1–3 mg/kg). Blockade of dopamine receptors with flupenthixol (0.25 mg/kg) before restraint did not attenuate stress-induced effects on effort-related choice, but abolished effects on choice latencies. These data suggest that acute stress interferes somewhat selectively with cost/benefit evaluations concerning effort costs. These effects do not appear to be mediated solely by enhanced glucocorticoid activity, whereas dopaminergic activation may contribute to increased deliberation times induced by stress. These findings may provide insight into impairments in decision-making and anergia associated with stress-related disorders, such as depression. PMID:22569506

  17. Selection of an evaluation index for water ecological civilizations of water-shortage cities based on the grey rough set

    Science.gov (United States)

    Zhang, X. Y.; Zhu, J. W.; Xie, J. C.; Liu, J. L.; Jiang, R. G.

    2017-08-01

    According to the characteristics and existing problems of water ecological civilization of water-shortage cities, the evaluation index system of water ecological civilization was established using a grey rough set. From six aspects of water resources, water security, water environment, water ecology, water culture and water management, this study established the prime frame of the evaluation system, including 28 items, and used rough set theory to undertake optimal selection of the index system. Grey correlation theory then was used for weightings in order that the integrated evaluation index system for water ecology civilization of water-shortage cities could be constituted. Xi’an City was taken as an example, for which the results showed that 20 evaluation indexes could be obtained after optimal selection of the preliminary framework of evaluation index. The most influential indices were the water-resource category index and water environment category index. The leakage rate of the public water supply pipe network, as well as the disposal, treatment and usage rate of polluted water, urban water surface area ratio, the water quality of the main rivers, and so on also are important. It was demonstrated that the evaluation index could provide an objectively reflection of regional features and key points for the development of water ecology civilization for cities with scarce water resources. It is considered that the application example has universal applicability.

  18. Hyperspectral detection of a subsurface CO2 leak in the presence of water stressed vegetation.

    Directory of Open Access Journals (Sweden)

    Gabriel J Bellante

    Full Text Available Remote sensing of vegetation stress has been posed as a possible large area monitoring tool for surface CO2 leakage from geologic carbon sequestration (GCS sites since vegetation is adversely affected by elevated CO2 levels in soil. However, the extent to which remote sensing could be used for CO2 leak detection depends on the spectral separability of the plant stress signal caused by various factors, including elevated soil CO2 and water stress. This distinction is crucial to determining the seasonality and appropriateness of remote GCS site monitoring. A greenhouse experiment tested the degree to which plants stressed by elevated soil CO2 could be distinguished from plants that were water stressed. A randomized block design assigned Alfalfa plants (Medicago sativa to one of four possible treatment groups: 1 a CO2 injection group; 2 a water stress group; 3 an interaction group that was subjected to both water stress and CO2 injection; or 4 a group that received adequate water and no CO2 injection. Single date classification trees were developed to identify individual spectral bands that were significant in distinguishing between CO2 and water stress agents, in addition to a random forest classifier that was used to further understand and validate predictive accuracies. Overall peak classification accuracy was 90% (Kappa of 0.87 for the classification tree analysis and 83% (Kappa of 0.77 for the random forest classifier, demonstrating that vegetation stressed from an underground CO2 leak could be accurately discerned from healthy vegetation and areas of co-occurring water stressed vegetation at certain times. Plants appear to hit a stress threshold, however, that would render detection of a CO2 leak unlikely during severe drought conditions. Our findings suggest that early detection of a CO2 leak with an aerial or ground-based hyperspectral imaging system is possible and could be an important GCS monitoring tool.

  19. Hyperspectral detection of a subsurface CO2 leak in the presence of water stressed vegetation.

    Science.gov (United States)

    Bellante, Gabriel J; Powell, Scott L; Lawrence, Rick L; Repasky, Kevin S; Dougher, Tracy

    2014-01-01

    Remote sensing of vegetation stress has been posed as a possible large area monitoring tool for surface CO2 leakage from geologic carbon sequestration (GCS) sites since vegetation is adversely affected by elevated CO2 levels in soil. However, the extent to which remote sensing could be used for CO2 leak detection depends on the spectral separability of the plant stress signal caused by various factors, including elevated soil CO2 and water stress. This distinction is crucial to determining the seasonality and appropriateness of remote GCS site monitoring. A greenhouse experiment tested the degree to which plants stressed by elevated soil CO2 could be distinguished from plants that were water stressed. A randomized block design assigned Alfalfa plants (Medicago sativa) to one of four possible treatment groups: 1) a CO2 injection group; 2) a water stress group; 3) an interaction group that was subjected to both water stress and CO2 injection; or 4) a group that received adequate water and no CO2 injection. Single date classification trees were developed to identify individual spectral bands that were significant in distinguishing between CO2 and water stress agents, in addition to a random forest classifier that was used to further understand and validate predictive accuracies. Overall peak classification accuracy was 90% (Kappa of 0.87) for the classification tree analysis and 83% (Kappa of 0.77) for the random forest classifier, demonstrating that vegetation stressed from an underground CO2 leak could be accurately discerned from healthy vegetation and areas of co-occurring water stressed vegetation at certain times. Plants appear to hit a stress threshold, however, that would render detection of a CO2 leak unlikely during severe drought conditions. Our findings suggest that early detection of a CO2 leak with an aerial or ground-based hyperspectral imaging system is possible and could be an important GCS monitoring tool.

  20. Transpiration efficiency and its relationship with carbon isotope discrimination under well-watered and water-stressed conditions in Stylosanthes scabra

    International Nuclear Information System (INIS)

    Thumma, B.R.; Naidu, B.P.; Cameron, D. F.; Bahnisch, L. M.

    1998-01-01

    Stylosanthes scabra cv. Seca is a widely sown tropical pasture legume in northern Australia and has a high degree of drought resistance. Identification of traits contributing to the drought resistance of Seca may be valuable for use in breeding programs. Transpiration efficiency (TE) has been suggested as one such trait contributing to drought resistance. Carbon isotope discrimination (Δ) has been proposed for estimating TE indirectly in C 3 plants. A glasshouse experiment was conducted using 8 accessions of S. scabra to identify whether Seca differs in TE from other accessions of S. scabra and to determine the relationship between TE and Δ) under both well-watered and water-stressed treatments. Seca maintained the highest TE (lowest Δ) under both control and stress treatments, and leaf Δ was significantly and negatively correlated with TE under both control and stress conditions. A significant and negative relationship was found between Δ and dry matter production under stress treatment. The interaction between accession and watering treatment was not significant for either TE or Δ. We also found a significant agreement between the performance in the field and in the laboratory for these 8 accessions. These results indicate that TE could be one of the significant factors contributing to drought resistance of Seca. Furthermore, Δ and/or specific leaf area may be useful as selection criteria in breeding programs to identify the lines with high TE. Copyright (1998) CSIRO Australia

  1. Infrared thermometry and the crop water stress index. II. Sampling procedures and interpretation

    Energy Technology Data Exchange (ETDEWEB)

    Gardner, B. R. [BP Research, Cleveland, OH (United States); Nielsen, D. C.; Shock, C. C.

    1992-10-15

    Infrared thermometry can be a valuable research and production tool for detecting and quantifying water stress in plants, as shown by a large volume of published research. Users of infrared thermometers (IRT) should be aware of the many equipment, environmental, and plant factors influencing canopy temperature measured by an IRT. The purpose of this paper is to describe factors influencing measured plant temperature, outline sampling procedures that will produce reliable Crop Water Stress Index (CWSI) values, and offer interpretations of CWSI and plant temperatures relative to crop production and other water stress parameters by reviewing previously conducted research. Factors that are considered are IRT condition, configuration, and position; psychrometer location; wind speed; solar radiation; time of day; leaf area and orientation; and appropriate non-water-stressed baseline equation. Standard sampling and CWSI calculation procedures are proposed. Use of CWSI with crops varying in type of response to water stress is described. Previously conducted research on plant temperatures or CWSI is tabulated by crop and water stress parameters measured. The paper provides valuable information to assist interested users of IRTs in making reliable water stress measurements. (author)

  2. Infrared thermometry and the crop water stress index. II. Sampling procedures and interpretation

    International Nuclear Information System (INIS)

    Gardner, B.R.; Nielsen, D.C.; Shock, C.C.

    1992-01-01

    Infrared thermometry can be a valuable research and production tool for detecting and quantifying water stress in plants, as shown by a large volume of published research. Users of infrared thermometers (IRT) should be aware of the many equipment, environmental, and plant factors influencing canopy temperature measured by an IRT. The purpose of this paper is to describe factors influencing measured plant temperature, outline sampling procedures that will produce reliable Crop Water Stress Index (CWSI) values, and offer interpretations of CWSI and plant temperatures relative to crop production and other water stress parameters by reviewing previously conducted research. Factors that are considered are IRT condition, configuration, and position; psychrometer location; wind speed; solar radiation; time of day; leaf area and orientation; and appropriate non-water-stressed baseline equation. Standard sampling and CWSI calculation procedures are proposed. Use of CWSI with crops varying in type of response to water stress is described. Previously conducted research on plant temperatures or CWSI is tabulated by crop and water stress parameters measured. The paper provides valuable information to assist interested users of IRTs in making reliable water stress measurements. (author)

  3. Partition distribution of selected organochlorine pesticides in water ...

    African Journals Online (AJOL)

    Organochlorine pesticides (OCPs) were analysed in surface water, pore water and surface sediment samples collected from the uMngeni River, which is one of the largest rivers in the province of KwaZulu-Natal, South Africa. Liquid-liquid extraction was used to extract the analytes from water and pore water samples and ...

  4. Selecting rice mutants with good agronomic performance under conditions of low water supplies

    International Nuclear Information System (INIS)

    González Cepero, María C.; Martínez Romero, Anirebis

    2016-01-01

    The present work is part of the researches that are carried out in the Regional Project of the International Organization of Atomic Energy (IAEA) Mutation Breeding of Alimentary Cultivations in Latin America where Cuba participates. The aim of this project is to obtain new rice varieties tolerant to drought using nuclear techniques, for that which is necessary to determine indicators for early selection of tolerant genotypes and to identify somaclones and/or mutants of good behavior under low water supply. For this study were used, 13 mutants obtained in the National Institute of Agricultural Sciences (INCA) as well as the rice varieties Amistad-82 and J-104. The response to the hydric stress under field conditions was determined, using irrigation during the first 45 days, interrupting later for the plant cycle, were determined: I) the height of the plant, II) weigh of 1000 grains, III) length of panicle, IV) number of full grains, V) vain grains, VI) number of panicle for lineal meter and VII) yield for square meter. Likewise in vitro the answers to the drought with a concentration of 5 g L-1 of PEG-6000 to simulate the hydric stress and the Relative Tolerance Index of root and of height were evaluated. Some indicators for early selection of tolerant genotypes starting from the existent correlation among the characters evaluated in the field in vivo and in vitro were also determined. The INCA genotypes LP-10 and 8552 showed a better behavior under conditions of low supplies of water and INCA LP 16 genotypes and mutant 8553 were the most susceptible because they could not panicular under the same conditions. (author)

  5. Factors affecting the selection of a soil water sensing technology

    International Nuclear Information System (INIS)

    Hignett, C.T.

    2000-01-01

    Reviews of soil moisture measurement technologies are counterproductive in attempting to identify the single approach that has the best overall performance for a range of soil, crop and landscape conditions. Not only does such an approach preclude the addition of new technologies, but it also obscures the fact that we have available today sensors and technologies that cover most field conditions, are well understood in terms of technical capability and are mechanically and electronically reliable. This review defines decision-making processes for assessing the characteristics, good and bad, of technology in relation to project objectives. Two processes are needed. The first links soil texture and scale of variability with the nature of the project, single-plant to catchment scale, to the needs for soil water measurement. The second lists the capabilities of some devices and shows how they can be selected to accommodate necessary criteria. It is concluded that the 'best technology' is a function of the project and soil conditions. (author)

  6. Assessment of Salicylic Acid Impacts on Seedling Characteristic of Cucumber (Cucumis sativus L. under Water Stress

    Directory of Open Access Journals (Sweden)

    Hossein MARDANI

    2012-02-01

    Full Text Available Impacts of various concentrations of salicylic acid (SA on cucumber (Cucumis sativus L. seedling characteristic were evaluated under different water stress levels by using a factorial arrangement based on completely randomized design with three replications at experimental greenhouse of Ferdowsi University of Mashhad, Iran. The studied factors included three water deficit levels (100% FC, 80% FC, and 60% FC considered as first factor and five levels of SA concentrations (0, 0.25, 0.5, 0.75, and 1 mM as second factor. Results showed that foliar application of SA at the highest concentration enhanced leaf area, leaf and dry weight while decreased stomatal conductance under high level of water deficit stress. Though, severe water deficit stress sharply raised the SPAD reading values. In general, exogenous SA application could develop cucumber seedling characteristic and improve water stress tolerance.

  7. Rehydration After Water Stress in Forager Workers of Coptotermes gestroi (Wasmann) (Blattaria: Rhinotermitidae).

    Science.gov (United States)

    Janei, V; Lima, J T; Costa-Leonardo, A M

    2015-06-01

    Water maintenance is vital for termite survival under dry conditions, hence environment humidity is one of the most important factors that controls the distribution of Isoptera. To understand the dynamics of termite rehydration after water loss, two bioassays were performed with forager workers of Coptotermes gestroi (Wasmann) submitted to water stress. Insects were weighed and placed into Petri dishes without water and food for periods of 3, 15, and 30 h. For each period of water stress, 10 replicates were performed in the treatment and control groups, totalling 120 experimental units. Forager workers lost body mass across all periods of water stress and tested with the highest reduction for the 30 h exposure period. Subsequent access to water resulted in termite rehydration, and final weight values were near to initial body mass values. These results demonstrate that workers of C. gestroi experienced large reductions of body mass under water stress, but these reductions were not severe enough to cause mortality. Additionally, termites were able to rehydrate after water stress conditions. This is a potential risk factor to be considered in cases of new infestations because C. gestroi workers will be able to cause economic damage in their new locations even when deprived of water during their transportation by humans.

  8. Food Selectivity, Mealtime Behavior Problems, Spousal Stress, and Family Food Choices in Children with and without Autism Spectrum Disorder

    Science.gov (United States)

    Curtin, C.; Hubbard, K.; Anderson, S. E.; Mick, E.; Must, A.; Bandini, L. G.

    2015-01-01

    Mealtime behavior problems and family stress occur frequently among families of children with autism spectrum disorder (ASD). However, it is unknown whether food selectivity is an associated factor. The associations of high food selectivity with mealtime behavior problems, spousal stress, and influence on family members were assessed among 53…

  9. Water stress projections for the northeastern and Midwestern United States in 2060: anthropogenic and ecological consequences

    Science.gov (United States)

    Brian G. Tavernia; Mark D. Nelson; Peter Caldwell; Ge Sun

    2013-01-01

    Future climate and land-use changes and growing human populations may reduce the abundance of water resources relative to anthropogenic and ecological needs in the Northeast and Midwest (U.S.). We used output from WaSSI, a water accounting model, to assess potential changes between 2010 and 2060 in (1) anthropogenic water stress for watersheds throughout the Northeast...

  10. Effects of water stress on photosynthetic electron transport, photophosphorylation, and metabolite levels of Xanthium strumarium mesophyll cells.

    Science.gov (United States)

    Sharkey, T D; Badger, M R

    1982-12-01

    Several component processes of photosynthesis were measured in osmotically stressed mesophyll cells of Xanthium strumarium L. The ribulose-1,5-bisphosphate regeneration capacity was reduced by water stress. Photophoshorylation was sensitive to water stress but photosynthetic electron transport was unaffected by water potentials down to-40 bar (-4 MPa). The concentrations of several intermediates of the photosynthetic carbon-reduction cycle remained relatively constant and did not indicate that ATP supply was limiting photosynthesis in the water-stressed cells.

  11. Additional Stress And Fracture Mechanics Analyses Of Pressurized Water Reactor Pressure Vessel Nozzles

    International Nuclear Information System (INIS)

    Walter, Matthew; Yin, Shengjun; Stevens, Gary; Sommerville, Daniel; Palm, Nathan; Heinecke, Carol

    2012-01-01

    In past years, the authors have undertaken various studies of nozzles in both boiling water reactors (BWRs) and pressurized water reactors (PWRs) located in the reactor pressure vessel (RPV) adjacent to the core beltline region. Those studies described stress and fracture mechanics analyses performed to assess various RPV nozzle geometries, which were selected based on their proximity to the core beltline region, i.e., those nozzle configurations that are located close enough to the core region such that they may receive sufficient fluence prior to end-of-life (EOL) to require evaluation of embrittlement as part of the RPV analyses associated with pressure-temperature (P-T) limits. In this paper, additional stress and fracture analyses are summarized that were performed for additional PWR nozzles with the following objectives: To expand the population of PWR nozzle configurations evaluated, which was limited in the previous work to just two nozzles (one inlet and one outlet nozzle). To model and understand differences in stress results obtained for an internal pressure load case using a two-dimensional (2-D) axi-symmetric finite element model (FEM) vs. a three-dimensional (3-D) FEM for these PWR nozzles. In particular, the ovalization (stress concentration) effect of two intersecting cylinders, which is typical of RPV nozzle configurations, was investigated. To investigate the applicability of previously recommended linear elastic fracture mechanics (LEFM) hand solutions for calculating the Mode I stress intensity factor for a postulated nozzle corner crack for pressure loading for these PWR nozzles. These analyses were performed to further expand earlier work completed to support potential revision and refinement of Title 10 to the U.S. Code of Federal Regulations (CFR), Part 50, Appendix G, Fracture Toughness Requirements, and are intended to supplement similar evaluation of nozzles presented at the 2008, 2009, and 2011 Pressure Vessels and Piping (PVP

  12. Water insecurity in a syndemic context: Understanding the psycho-emotional stress of water insecurity in Lesotho, Africa.

    Science.gov (United States)

    Workman, Cassandra L; Ureksoy, Heather

    2017-04-01

    Syndemics occur when populations experience synergistic and multiplicative effects of co-occurring epidemics. Proponents of syndemic theory highlight the importance of understanding the social context in which diseases spread and cogently argue that there are biocultural effects of external stresses such as food insecurity and water insecurity. Thus, a holistic understanding of disease or social vulnerability must incorporate an examination of the emotional and social effects of these phenomena. This paper is a response to the call for a renewed focus on measuring the psycho-emotional and psychosocial effects of food insecurity and water insecurity. Using a mixed-method approach of qualitative interviews and quantitative assessment, including a household demographic, illness, and water insecurity scale, the Household Food Insecurity Access Scale, and the Hopkins Symptoms Checklist-25, this research explored the psycho-emotional effects of water insecurity, food insecurity, and household illness on women and men residing in three low-land districts in Lesotho (n = 75). Conducted between February and November of 2011, this exploratory study first examined the complicated interaction of water insecurity, food insecurity and illness to understand and quantify the relationship between these co-occurring stresses in the context of HIV/AIDS. Second, it sought to separate the role of water insecurity in predicting psycho-emotional stress from other factors, such as food insecurity and household illness. When asked directly about water, qualitative research revealed water availability, access, usage amount, and perceived water cleanliness as important dimensions of water insecurity, creating stress in respondents' daily lives. Qualitative and quantitative data show that water insecurity, food insecurity and changing household demographics, likely resulting from the HIV/AIDS epidemic, are all associated with increased anxiety and depression, and support the conclusion that

  13. Electrostatic tuning of permeation and selectivity in aquaporin water channels

    DEFF Research Database (Denmark)

    Jensen, Mogens O Stibius; Tajkhorshid, E.; Schulten, K.

    2003-01-01

    Water permeation and electrostatic interactions between water and channel are investigated in the Escherichia coli glycerol uptake facilitator GlpF, a member of the aquaporin water channel family, by molecular dynamics simulations. A tetrameric model of the channel embedded in a 16:0/ 18:1c9...... with the protein electrostatic fields enforce a bipolar water configuration inside the channel with dipole inversion at the NPA motifs. At the NPA motifs water-protein electrostatic interactions facilitate this inversion. Furthermore, water-water electrostatic interactions are in all regions inside the channel...... stronger than water-protein interactions, except near a conserved, positively charged Arg residue. We find that variations of the protein electrostatic field through the channel, owing to preserved structural features, completely explain the bipolar orientation of water. This orientation persists despite...

  14. Metallurgical and mechanical parameters controlling alloy 718 stress corrosion cracking resistance in PWR primary water

    International Nuclear Information System (INIS)

    Deleume, J.

    2007-11-01

    Improving the performance and reliability of the fuel assemblies of the pressurized water reactors requires having a perfect knowledge of the operating margins of both the components and the materials. The choice of alloy 718 as reference material for this study is justified by the industrial will to identify the first order parameters controlling the excellent resistance of this alloy to Stress Corrosion Cracking (SCC). For this purpose, a specific slow strain rate (SSR) crack initiation test using tensile specimen with a V-shaped hump in the middle of the gauge length was developed and modeled. The selectivity of such SSR tests in simulated PWR primary water at 350 C was clearly established by characterizing the SCC resistance of nine alloy 718 thin strip heats. Regardless of their origin and in spite of a similar thermo-mechanical history, they did not exhibit the same susceptibility to SCC crack initiation. All the characterized alloy 718 heats develop oxide scale of similar nature for various exposure times to PWR primary medium in the temperature range [320 C - 360 C]. δ phase precipitation has no impact on alloy 718 SCC initiation behavior when exposed to PWR primary water, contrary to interstitial contents and the triggering of plastic instabilities (PLC phenomenon). (author)

  15. The influence of stress conditions on the growth of selected lactic acid bacteria

    International Nuclear Information System (INIS)

    Bok, H.E.

    1985-01-01

    A study was undertaken to determine the effects of certain stress conditions on selected lactic acid bacteria. Where recontamination occurred, lactic acid bacteria was already the dominant bacterial group, with counts of higher than 10 6 /g in vacuum-packaged 'shelf stable' meat products after 1 week storage at 25 and 37 degrees Celsius respectively. Some of the isolates were capable of growing at a pH of 3,9. The minimum pH for growth of a specific culture was dependant on the type of acid that was used to lower the pH. Lactic and acetic acid had the highest inhibitory action. Hydrochloric and citric acid showed similar inhibitory effects, while the effects when using ascorbic acid or gluconic acid for lowering the pH were also fairly similar. Increase in the activity of certain lactic acid bacteria was noticed where the ratio of undissociated to dissociated citric acid in the medium was increased. After exceeding a concentration of 0,048 moles/l undissosiated citric acid in the medium, the activity of the majority of cultures was progressively inhibited. This phenomenon was also found with acetic acid for certain cultures. Selected lactic acid bacteria were resistant to an water activity (a (sub w)) of 0,94 in MRS broth, where NaCl or glycerol was used as a humectant. The minimum a (sub w) for growth was dependent on the type of humectant used. Concentrations of sodium benzoate and potassium sorbate were necessary to inhibit the majority of strains. The % inhibition by sodium benzoate and methyl paraben did not significantly change with a lowering in the pH of the growth medium. Except in the case of lactic acid, the different acids used to lower the pH of the medium did not have a significant effect on the % inhibition by the chemical preservatives. For the cocci, gamma D 10 values of between 0,82 and 1,29 kGy were recorded, whereas the lactobacilli were less resistant to gamma rays, with D 10 values of between 0,21 and 0,54 kGy

  16. High carotenoids content can enhance resistance of selected Pinctada fucata families to high temperature stress.

    Science.gov (United States)

    Meng, Zihao; Zhang, Bo; Liu, Baosuo; Li, Haimei; Fan, Sigang; Yu, Dahui

    2017-02-01

    Carotenoids are a class of natural antioxidants widely found in aquatic, and they have significant effects on the growth, survival, and immunity of these organisms. To investigate the mechanisms of carotenoids in high temperature resistance, we observed the immune response of selected pearl oyster Pinctada fucata (Akoya pearl oyster) families with different carotenoids contents to high temperature stress. The results indicated that the survival rate (SR) of P. fucata decreased significantly with increase in temperature from 26 °C to 34 °C and with the decrease of total carotenoids content (TCC); when the TCC was higher, the SR tended to be higher. TCC and total antioxidant capacity (TAC) decreased significantly at 30 °C with increasing stress time. Correlation analysis indicated that TAC was positively and linearly correlated with TCC, and SR was S-type correlated with TCC and TAC. Immune analysis indicated that levels of superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA) in selected families (with higher TCC) under temperature stress (at 30 °C) were generally significantly lower than in the control group (with lowest TCC) and from 0 to 96 h, the levels of each of these substances varied significantly. Levels of SOD, CAT, and MDA within each family first rose from 0 to 3 h, then decreased to their lowest point after 24 h, and then rose again to their highest levels at 96 h. When TCC was higher, the levels of SOD, CAT, and MDA tended to be lower. These findings indicated that carotenoids play an important role in improving survival rates of P. fucata under high temperature stress by enhancing animals' antioxidant system, and could serve as an index for breeding stress-resistant lines in selective breeding practices. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Gas exchange and hydraulics in seedlings of Hevea brasiliensis during water stress and recovery.

    Science.gov (United States)

    Chen, Jun-Wen; Zhang, Qiang; Li, Xiao-Shuang; Cao, Kun-Fang

    2010-07-01

    The response of plants to drought has received significant attention, but far less attention has been given to the dynamic response of plants during recovery from drought. Photosynthetic performance and hydraulic capacity were monitored in seedlings of Hevea brasiliensis under water stress and during recovery following rewatering. Leaf water relation, gas exchange rate and hydraulic conductivity decreased gradually after water stress fell below a threshold, whereas instantaneous water use efficiency and osmolytes increased significantly. After 5 days of rewatering, leaf water relation, maximum stomatal conductance (g(s-max)) and plant hydraulic conductivity had recovered to the control levels except for sapwood area-specific hydraulic conductivity, photosynthetic assimilation rate and osmolytes. During the phase of water stress, stomata were almost completely closed before water transport efficiency decreased substantially, and moreover, the leaf hydraulic pathway was more vulnerable to water stress-induced embolism than the stem hydraulic pathway. Meanwhile, g(s-max) was linearly correlated with hydraulic capacity when water stress exceeded a threshold. In addition, a positive relationship was shown to occur between the recovery of g(s-max) and of hydraulic capacity during the phase of rewatering. Our results suggest (i) that stomatal closure effectively reduces the risk of xylem dysfunction in water-stressed plants at the cost of gas exchange, (ii) that the leaf functions as a safety valve to protect the hydraulic pathway from water stress-induced dysfunction to a larger extent than does the stem and (iii) that the full drought recovery of gas exchange is restricted by not only hydraulic factors but also non-hydraulic factors.

  18. Chronic water stress reduces tree growth and the carbon sink of deciduous hardwood forests.

    Science.gov (United States)

    Brzostek, Edward R; Dragoni, Danilo; Schmid, Hans Peter; Rahman, Abdullah F; Sims, Daniel; Wayson, Craig A; Johnson, Daniel J; Phillips, Richard P

    2014-08-01

    Predicted decreases in water availability across the temperate forest biome have the potential to offset gains in carbon (C) uptake from phenology trends, rising atmospheric CO2 , and nitrogen deposition. While it is well established that severe droughts reduce the C sink of forests by inducing tree mortality, the impacts of mild but chronic water stress on forest phenology and physiology are largely unknown. We quantified the C consequences of chronic water stress using a 13-year record of tree growth (n = 200 trees), soil moisture, and ecosystem C balance at the Morgan-Monroe State Forest (MMSF) in Indiana, and a regional 11-year record of tree growth (n > 300 000 trees) and water availability for the 20 most dominant deciduous broadleaf tree species across the eastern and midwestern USA. We show that despite ~26 more days of C assimilation by trees at the MMSF, increasing water stress decreased the number of days of wood production by ~42 days over the same period, reducing the annual accrual of C in woody biomass by 41%. Across the deciduous forest region, water stress induced similar declines in tree growth, particularly for water-demanding 'mesophytic' tree species. Given the current replacement of water-stress adapted 'xerophytic' tree species by mesophytic tree species, we estimate that chronic water stress has the potential to decrease the C sink of deciduous forests by up to 17% (0.04 Pg C yr(-1) ) in the coming decades. This reduction in the C sink due to mesophication and chronic water stress is equivalent to an additional 1-3 days of global C emissions from fossil fuel burning each year. Collectively, our results indicate that regional declines in water availability may offset the growth-enhancing effects of other global changes and reduce the extent to which forests ameliorate climate warming. © 2014 John Wiley & Sons Ltd.

  19. Effects of Nutrients Foliar Application on Agrophysiological Characteristics of Maize under Water Deficit Stress

    Directory of Open Access Journals (Sweden)

    Nour Ali SAJEDI

    2010-09-01

    Full Text Available To investigate effects of nutrients foliar application on agrophysiological characteristics of maize hybrid �KSC 704� water deficit stress conditions, an experiment was arranged in a split plot factorial based on a randomized complete block design with four replications to the Research Station of Islamic Azad University-Arak Branch, Iran in 2007-2008. Main factors studied were four irrigation levels including irrigation equal to crop water requirement, water deficit stress at eight-leaf stage (V8, blister stage (R2 and filling grain stage (R4 in the main plot. Combined levels of selenium treatment (without and with application 20 gha-1 and micronutrients (without and with application 2 lha-1 were situated in sub plots. Results showed that water deficit stress decreased grain yield 19.7% in blister stage as compared with control. Using selenium increased relative content water at R2 and R4 stages significantly. Using selenium in water deficit stress condition increased measured traits except plant height as compared with treatment without selenium. A negative antagonistic interaction was found between selenium and micronutrients on some measured traits. Between treatments of water deficit stress, highest grain yield equal 6799.52 and 6736.97 kgha-1 was obtained from combined treatments of water deficit stress at eight-leaf stage+without selenium+without micronutrients and water deficit stress at eight-leaf stage+selenium+without micronutrients respectively which compared with treatment of irrigation equal to crop water requirement+selenium+microelements did not differ significant. According to the results of experiment, it is concluded that with micronutrients fertilizer spray under optimum irrigation and selenium spray under water deficit obtain optimum yield.

  20. Acute stress alters auditory selective attention in humans independent of HPA: a study of evoked potentials.

    Directory of Open Access Journals (Sweden)

    Ludger Elling

    Full Text Available BACKGROUND: Acute stress is a stereotypical, but multimodal response to a present or imminent challenge overcharging an organism. Among the different branches of this multimodal response, the consequences of glucocorticoid secretion have been extensively investigated, mostly in connection with long-term memory (LTM. However, stress responses comprise other endocrine signaling and altered neuronal activity wholly independent of pituitary regulation. To date, knowledge of the impact of such "paracorticoidal" stress responses on higher cognitive functions is scarce. We investigated the impact of an ecological stressor on the ability to direct selective attention using event-related potentials in humans. Based on research in rodents, we assumed that a stress-induced imbalance of catecholaminergic transmission would impair this ability. METHODOLOGY/PRINCIPAL FINDINGS: The stressor consisted of a single cold pressor test. Auditory negative difference (Nd and mismatch negativity (MMN were recorded in a tonal dichotic listening task. A time series of such tasks confirmed an increased distractibility occurring 4-7 minutes after onset of the stressor as reflected by an attenuated Nd. Salivary cortisol began to rise 8-11 minutes after onset when no further modulations in the event-related potentials (ERP occurred, thus precluding a causal relationship. This effect may be attributed to a stress-induced activation of mesofrontal dopaminergic projections. It may also be attributed to an activation of noradrenergic projections. Known characteristics of the modulation of ERP by different stress-related ligands were used for further disambiguation of causality. The conjuncture of an attenuated Nd and an increased MMN might be interpreted as indicating a dopaminergic influence. The selective effect on the late portion of the Nd provides another tentative clue for this. CONCLUSIONS/SIGNIFICANCE: Prior studies have deliberately tracked the adrenocortical influence

  1. Fundamental approaches to predicting stress corrosion: 'Quantitative micro-nano' (QMN) approach to predicting stress corrosion cracking in water cooled nuclear plants

    International Nuclear Information System (INIS)

    Staehle, R.W.

    2010-01-01

    This paper describes the modeling and experimental studies of stress corrosion cracking with full disciplinary set at the atomic level. Its objective is to develop an intellectual structure for quantitative prediction of stress corrosion cracking in water cooled reactors.

  2. Economics of Selected Water Control Technologies and their ...

    African Journals Online (AJOL)

    management, water for multiple use systems and all relevant aspects of ... would add to our understanding of adoption decisions (Doss, 2006). ... Methodology .... International Water Management Institute (IWMI) with support from United States.

  3. Determination of selected heavy metals in inland fresh water of ...

    African Journals Online (AJOL)

    Agadaga

    Key words: Heavy metals, freshwater, concentrations, quality, variation, distribution. ... prevalence of heavy metals in inland water of lower River. Niger drain are scarce ..... Niger waters at Ajaokuta were found to be low and within guideline.

  4. Hydraulic failure defines the recovery and point of death in water-stressed conifers.

    Science.gov (United States)

    Brodribb, Tim J; Cochard, Hervé

    2009-01-01

    This study combines existing hydraulic principles with recently developed methods for probing leaf hydraulic function to determine whether xylem physiology can explain the dynamic response of gas exchange both during drought and in the recovery phase after rewatering. Four conifer species from wet and dry forests were exposed to a range of water stresses by withholding water and then rewatering to observe the recovery process. During both phases midday transpiration and leaf water potential (Psileaf) were monitored. Stomatal responses to Psileaf were established for each species and these relationships used to evaluate whether the recovery of gas exchange after drought was limited by postembolism hydraulic repair in leaves. Furthermore, the timing of gas-exchange recovery was used to determine the maximum survivable water stress for each species and this index compared with data for both leaf and stem vulnerability to water-stress-induced dysfunction measured for each species. Recovery of gas exchange after water stress took between 1 and >100 d and during this period all species showed strong 1:1 conformity to a combined hydraulic-stomatal limitation model (r2 = 0.70 across all plants). Gas-exchange recovery time showed two distinct phases, a rapid overnight recovery in plants stressed to 50% loss of Kleaf. Maximum recoverable water stress (Psimin) corresponded to a 95% loss of Kleaf. Thus, we conclude that xylem hydraulics represents a direct limit to the drought tolerance of these conifer species.

  5. Nondestructive detection of water stress in tomato [Lycopersicon esculentum] plants using microwave sensing, 2

    International Nuclear Information System (INIS)

    Shimomachi, T.; Takemasa, T.; Kurata, K.; Takakura, T.

    2004-01-01

    The physiological accommodation response to environmental stress of a plant can induce changes in physiological and physical conditions of the plant. These changes influence the dielectric properties of the plant, which can be detected by measuring microwave complex dielectric properties of plant materials such as leaves and stems. The objective of this research was to detect these responses of plants to water deficiency stress nondestructively. The complex dielectric properties of tomato leaves during water stress were measured with an Open-ended Coaxial Probe from 0.3 to 3 GHz, as well as changes in gravimetric moisture, photosynthetic rate, stomatal conductance and water potential which reflect the physiological condition of the plants. Experimental results showed that the complex permittivity (both permittivity and loss factor) of tomato leaves increased during water stress. Of the parameters measured the highest correlation was observed between complex permittivity and water potential. In order to confirm these results, control and water deficient tomato leaves were crushed, and the complex permittivity was measured and compared. The results showed quite similar tendencies compared with the results from the nondestructive microwave measurements. A physiochemical model to describe the complex permittivity of crushed non-stressed and stressed tomato leaves was constructed with pure water, pulp, glycine, and KN03, and the complex dielectric measurements of crushed tomato leaves were reproduced quite accurately from 0.3 to 3 GHz

  6. Modelling global water stress of the recent past: on the relative importance of trends in water demand and climate variability

    Science.gov (United States)

    Wada, Y.; van Beek, L. P. H.; Bierkens, M. F. P.

    2011-08-01

    During the past decades, human water use more than doubled, yet available freshwater resources are finite. As a result, water scarcity has been prevalent in various regions of the world. Here, we present the first global assessment of past development of water scarcity considering not only climate variability but also growing water demand, desalinated water use and non-renewable groundwater abstraction over the period 1960-2001 at a spatial resolution of 0.5°. Agricultural water demand is estimated based on past extents of irrigated areas and livestock densities. We approximate past economic development based on GDP, energy and household consumption and electricity production, which is subsequently used together with population numbers to estimate industrial and domestic water demand. Climate variability is expressed by simulated blue water availability defined by freshwater in rivers, lakes and reservoirs by means of the global hydrological model PCR-GLOBWB. The results show a drastic increase in the global population living under water-stressed conditions (i.e., moderate to high water stress) due to the growing water demand, primarily for irrigation, which more than doubled from 1708/818 to 3708/1832 km3 yr-1 (gross/net) over the period 1960-2000. We estimate that 800 million people or 27 % of the global population were under water-stressed conditions for 1960. This number increased to 2.6 billion or 43 % for 2000. Our results indicate that increased water demand is the decisive factor for the heightened water stress, enhancing the intensity of water stress up to 200 %, while climate variability is often the main determinant of onsets for extreme events, i.e. major droughts. However, our results also suggest that in several emerging and developing economies (e.g., India, Turkey, Romania and Cuba) some of the past observed droughts were anthropogenically driven due to increased water demand rather than being climate-induced. In those countries, it can be seen

  7. Adapting to Water Stress in the Comahue Region of Argentina ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    , quality, and distribution -generate local and regional climate and hydrological models and scenarios for mid- and long-term water availability -assess current water availability, use, and distribution in sub-regions of the Comahue and provide ...

  8. Water footprint of growing vegetables in selected smallholder ...

    African Journals Online (AJOL)

    Crop water footprint (WF) is the volume of fresh water used to produce a certain crop in all the steps in the production line. The CROPWAT model was used to calculate crop evapotranspiration, differentiating green and blue water in Zanyokwe (ZIS), Thabina (TIS) and Tugela Ferry (TFIS) Irrigation Schemes. Green beans ...

  9. Food selectivity and processing by the cold-water coral

    NARCIS (Netherlands)

    Van Oevelen, D.; Mueller, C.E.; Lundälv, T.; Middelburg, J.J.

    2016-01-01

    Cold-water corals form prominent reef ecosystemsalong ocean margins that depend on suspended resourcesproduced in surface waters. In this study, we investigatedfood processing of 13C and 15N labelled bacteria and algaeby the cold-water coral Lophelia pertusa. Coral respiration,tissue incorporation

  10. Effects of water stress and seed mass on germination and ...

    African Journals Online (AJOL)

    enoh

    2012-03-01

    Mar 1, 2012 ... polyvinylpyrrolidone; TCA, trichloroacetic acid; NBT, nitroblue tetrazolium; TBA ..... seeds had weaker resistances to moderate stress (-0.6. MPa) compared with .... Chen YN,Chen YP,Li WH,Zhang HF (2003). Response of ...

  11. Effects of salinity stress on water uptake, germination and early ...

    African Journals Online (AJOL)

    Administrator

    2011-09-07

    Sep 7, 2011 ... Department of Field Crops, Faculty of Agriculture, Namik Kemal University, 59100 Tekirdag, ..... stresses on germination in durum wheat (Triticum durum Desf.) .... transgenic perennial ryegrass (Lolium perenne L.) obtained by.

  12. Comparative evaluation of human heat stress indices on selected hospital admissions in Sydney, Australia.

    Science.gov (United States)

    Goldie, James; Alexander, Lisa; Lewis, Sophie C; Sherwood, Steven

    2017-08-01

    To find appropriate regression model specifications for counts of the daily hospital admissions of a Sydney cohort and determine which human heat stress indices best improve the models' fit. We built parent models of eight daily counts of admission records using weather station observations, census population estimates and public holiday data. We added heat stress indices; models with lower Akaike Information Criterion scores were judged a better fit. Five of the eight parent models demonstrated adequate fit. Daily maximum Simplified Wet Bulb Globe Temperature (sWBGT) consistently improved fit more than most other indices; temperature and heatwave indices also modelled some health outcomes well. Humidity and heat-humidity indices better fit counts of patients who died following admission. Maximum sWBGT is an ideal measure of heat stress for these types of Sydney hospital admissions. Simple temperature indices are a good fallback where a narrower range of conditions is investigated. Implications for public health: This study confirms the importance of selecting appropriate heat stress indices for modelling. Epidemiologists projecting Sydney hospital admissions should use maximum sWBGT as a common measure of heat stress. Health organisations interested in short-range forecasting may prefer simple temperature indices. © 2017 The Authors.

  13. Effect of water stress on in vitro mycelium cultures of two mycorrhizal desert truffles.

    Science.gov (United States)

    Navarro-Ródenas, Alfonso; Lozano-Carrillo, M Cecilia; Pérez-Gilabert, Manuela; Morte, Asunción

    2011-05-01

    The ability of two species of desert truffle, Terfezia claveryi strain TcS2 and Picoa lefebvrei strain OL2, to tolerate water stress in pure culture has been investigated. Both T. claveryi and P. lefebvrei strains exhibited a mycelium growth pattern characteristic of drought tolerant species. However, they were only tolerant to moderate water stress, below -1.07 MPa, with the P. lefebvrei isolate being slightly more drought tolerant than the T. claveryi isolate. The increased alkaline phosphatase (ALP) activity observed in both fungi at moderate water stress with respect to the control indicated the functional adaptation of these mycelia to these drought conditions. ALP activity can be used as an indicator of the metabolic activity of these fungi. Slight water stress (-0.45 MPa) could improve mycelial inoculum production of these desert truffles. Moreover, P. lefebvrei could be a good candidate for further desert truffle mycorrhizal plant cultivation programmes in semiarid Mediterranean areas.

  14. Effects of water stress on germination of Pinus nigra Arnold. seeds

    International Nuclear Information System (INIS)

    Topacoglu, O.; Sevik, H.; Akkuzu, E.

    2016-01-01

    Climate change, global warming and the deterioration of related environmental conditions cause an important problem for forest tree species. For this reason, it is necessary to determine the response of trees to these conditions. The Objective of this study was to investigate the effects of water stress on seed germination of fifteen Pinus nigra Arnold. provenances in Turkey. For this purpose, the water stresses between 0 and -8.0 bars were obtained using polyethylene glycol-6000 (PEG) solutions. Seeds were kept for 35 days at 20 ± 0.5 degree C. In this study, significant variations between the provenances were found. Ankara Uluhan ( percent 95, 08) and Isparta Tota ( percent 85, 41) provenances at -8.0 bars having the highest cumulative germination percentages were the most resistant provenances against the water stress. This study has shown that the water stress reduced the germination speed, germination percentage and germination value. (author)

  15. Stress corrosion cracking of equipment materials in domestic pressurized water reactors and the relevant safety management

    International Nuclear Information System (INIS)

    Sun Haitao

    2015-01-01

    International and domestic research and project state about stress corrosion cracking of nuclear equipments and materials (including austenitic stainless steel and nickel based alloys) in pressurized water reactor are discussed, and suggestions on how to prevent, mitigate ana deal with the stress corrosion cracking issues in domestic reactors are given in this paper based on real case analysis and study ondomestic nuclear equipment and material stress corrosion cracking failure. (author)

  16. Effect of Water Deficit Stress on Peach Growth under Commercial Orchard Management Conditions

    Directory of Open Access Journals (Sweden)

    M. Rahmati

    2015-06-01

    Full Text Available In order to study the sensitivity of vegetative growth to water deficit stress of a late-maturing peach (Prunus persica L. cv. Elberta under orchard conditions, an experiment was conducted as randomized complete-block design with three treatments and four repetitions in Shahdiran commercial orchard in Mashhad during 2011. Three irrigation treatments including 360 (low stress, 180 (moderate stress and 90 (severe stress m3ha-1week-1 using a drip irrigation system (minimum stem water potential near harvest: -1.2, -1.5 and -1.7 MPa, respectively from the mid-pit hardening stage (12th of June until harvest (23rd of Sep. applied. Predawn, stem and leaf water potentials, leaf photosynthesis, transpiration, stomatal conductance and leaf temperature, the number of new shoots on fruit bearing shoots and vegetative shoots lengths during growing season as well as leaf area at harvest were measured. The results showed that water deficit stress had negative effects on peach tree water status, thereby resulting in decreased leaf gas exchange and tree vegetative growth. As significant decreased assimilate production of tree was resulted from both decreased leaf assimilation rate (until about 23 % and 50 %, respectively under moderate and severe stress conditions compared to low stress conditions and decreased leaf area of tree (until about 57% and 79%, respectively under moderate and severe stress conditions compared to low stress conditions at harvest. The significant positive correlation between leaf water potential and vegetative growth of peach revealed that shoot growth would decrease by 30% and 50% of maximum at leaf water potential of –1.56 and –2.30 MPa, respectively.

  17. Physiological changes of pepper accessions in response to salinity and water stress

    Energy Technology Data Exchange (ETDEWEB)

    López-Serrano, L.; Penella, C.; San Bautista, A.; López-Galarza, S.; Calatayud, A.

    2017-07-01

    New sources of water stress and salinity tolerances are needed for crops grown in marginal lands. Pepper is considered one of the most important crops in the world. Many varieties belong to the genus Capsicum spp., and display wide variability in tolerance/sensitivity terms in response to drought and salinity stress. The objective was to screen seven salt/drought-tolerant pepper accessions to breed new cultivars that could overcome abiotic stresses, or be used as new crops in land with water and salinity stress. Fast and effective physiological traits were measured to achieve the objective. The present study showed wide variability of the seven pepper accessions in response to both stresses. Photosynthesis, stomatal conductance and transpiration reduced mainly under salinity due to stomatal and non-stomatal (Na+ accumulation) constraints and, to a lesser extent, in the accessions grown under water stress. A positive relationship between CO2 fixation and fresh weight generation was observed for both stresses. Decreases in Ys and YW and increased proline were observed only when accessions were grown under salinity. However, these factors were not enough to alleviate salt effects and an inverse relation was noted between plant salt tolerance and proline accumulation. Under water stress, A31 was the least affected and A34 showed the best tolerance to salinity in terms of photosynthesis and biomass.

  18. Metal balance shift induced in small fresh water fish by several environmental stresses

    International Nuclear Information System (INIS)

    Yukawa, Masae; Iso, Hiroyuki; Kodama, Kumiko; Imaseki, Hitoshi; Aoki, Kazuko; Ishikawa, Yuji

    2005-01-01

    Balance of essential elements in organisms might be changed by environmental stresses. Small fresh water fish, Medaka, was burdened with X-ray irradiation (total dose: 17 Gy), keeping in salty water (70% NaCl of sea water) and keeping in metal containing water (10 ppm of Cr and Co). These stresses are not lethal doses. Essential elements in liver, gall bladder, kidney, spleen, heart and brain in the stress-loaded fish were measured by PIXE method and compared with a control fish to determine the effect of the stresses. Various changes of the elemental contents were observed. Effect of X-ray irradiation was the smallest among the stresses. Relatively high content elements such as P, S, Cl and K were hardly affected with the stresses examined in this work. The effect of Cr on the metal balance seems to be larger than the other stresses. As PIXE method can analyze many elements in a small sample simultaneously, change of elemental distribution in small organisms induced by environmental stresses can be determined readily. (author)

  19. Physiological changes of pepper accessions in response to salinity and water stress

    International Nuclear Information System (INIS)

    López-Serrano, L.; Penella, C.; San Bautista, A.; López-Galarza, S.; Calatayud, A.

    2017-01-01

    New sources of water stress and salinity tolerances are needed for crops grown in marginal lands. Pepper is considered one of the most important crops in the world. Many varieties belong to the genus Capsicum spp., and display wide variability in tolerance/sensitivity terms in response to drought and salinity stress. The objective was to screen seven salt/drought-tolerant pepper accessions to breed new cultivars that could overcome abiotic stresses, or be used as new crops in land with water and salinity stress. Fast and effective physiological traits were measured to achieve the objective. The present study showed wide variability of the seven pepper accessions in response to both stresses. Photosynthesis, stomatal conductance and transpiration reduced mainly under salinity due to stomatal and non-stomatal (Na+ accumulation) constraints and, to a lesser extent, in the accessions grown under water stress. A positive relationship between CO2 fixation and fresh weight generation was observed for both stresses. Decreases in Ys and YW and increased proline were observed only when accessions were grown under salinity. However, these factors were not enough to alleviate salt effects and an inverse relation was noted between plant salt tolerance and proline accumulation. Under water stress, A31 was the least affected and A34 showed the best tolerance to salinity in terms of photosynthesis and biomass.

  20. Impacts of Climate Variability on the Spatio-temporal Characteristics of Water Stress in Korea

    Science.gov (United States)

    Kim, Soojun; Devineni, Naresh; Lall, Upmanu; Kim, Hung Soo

    2017-04-01

    This study intended to evaluate water stress quantitatively targeted at the Korean Peninsula and to analyze the spatial and temporal characteristics of its occurrence. First, the severity and multiyear influence of water stress were analyzed by realizing water balance based on water supply and demand and by calculating the normalized deficit index (NDI) and the normalized deficit cumulated (NDC) for 113 small basins in the Korean Peninsula. Next, a change in the periodic characteristics of water stress was analyzed using wavelet transform of the NDI by small basins and 3 bands of periods of 1 year, 2-4 years, and 4-8 years were separated. Through an analysis of the empirical orthogonal function (EOF) on each band, it was found that water stress occurring in the Korean Peninsula has the characteristics of spatial distribution that it is extended from the south coast to the northern area and inland as its period gets longer. An analysis of the band with a period of 2-8 years for water stress showed that it has a relationship with El Niño-Southern Oscillation (ENSO). Acknowledgment This research was supported by a grant (14AWMP-B082564-01) from Advanced Water Management Research Program funded by Ministry of Land, Infrastructure and Transport of Korean government.

  1. Water deficit stress-induced changes in carbon and nitrogen partitioning in Chenopodium quinoa Willd.

    Science.gov (United States)

    Bascuñán-Godoy, Luisa; Reguera, Maria; Abdel-Tawab, Yasser M; Blumwald, Eduardo

    2016-03-01

    Water deficit stress followed by re-watering during grain filling resulted in the induction of the ornithine pathway and in changes in Quinoa grain quality. The genetic diversity of Chenopodium quinoa Willd. (Quinoa) is accompanied by an outstanding environmental adaptability and high nutritional properties of the grains. However, little is known about the biochemical and physiological mechanisms associated with the abiotic stress tolerance of Quinoa. Here, we characterized carbon and nitrogen metabolic changes in Quinoa leaves and grains in response to water deficit stress analyzing their impact on the grain quality of two lowland ecotypes (Faro and BO78). Differences in the stress recovery response were found between genotypes including changes in the activity of nitrogen assimilation-associated enzymes that resulted in differences in grain quality. Both genotypes showed a common strategy to overcome water stress including the stress-induced synthesis of reactive oxygen species scavengers and osmolytes. Particularly, water deficit stress induced the stimulation of the ornithine and raffinose pathways. Our results would suggest that the regulation of C- and N partitioning in Quinoa during grain filling could be used for the improvement of the grain quality without altering grain yields.

  2. Water and temperature stress define the optimal flowering period for wheat in south-eastern Australia

    OpenAIRE

    Evans, John; Kirkegaard, John; Hunt, James; Flohr, Bonnie

    2017-01-01

    Across the Australian wheat belt, the time at which wheat flowers is a critical determinant of yield. In all environments an optimal flowering period (OFP) exists which is defined by decreasing frost risk, and increasing water and heat stress. Despite their critical importance, OFPs have not been comprehensively defined across south eastern Australia′s (SEA) cropping zone using yield estimates incorporating temperature, radiation and water-stress. In this study, the widely validated cropping ...

  3. Nitrogen Metabolism in Adaptation of Photosynthesis to Water Stress in Rice Grown under Different Nitrogen Levels

    Directory of Open Access Journals (Sweden)

    Chu Zhong

    2017-06-01

    Full Text Available To investigate the role of nitrogen (N metabolism in the adaptation of photosynthesis to water stress in rice, a hydroponic experiment supplying with low N (0.72 mM, moderate N (2.86 mM, and high N (7.15 mM followed by 150 g⋅L-1 PEG-6000 induced water stress was conducted in a rainout shelter. Water stress induced stomatal limitation to photosynthesis at low N, but no significant effect was observed at moderate and high N. Non-photochemical quenching was higher at moderate and high N. In contrast, relative excessive energy at PSII level (EXC was declined with increasing N level. Malondialdehyde and hydrogen peroxide (H2O2 contents were in parallel with EXC. Water stress decreased catalase and ascorbate peroxidase activities at low N, resulting in increased H2O2 content and severer membrane lipid peroxidation; whereas the activities of antioxidative enzymes were increased at high N. In accordance with photosynthetic rate and antioxidative enzymes, water stress decreased the activities of key enzymes involving in N metabolism such as glutamate synthase and glutamate dehydrogenase, and photorespiratory key enzyme glycolate oxidase at low N. Concurrently, water stress increased nitrate content significantly at low N, but decreased nitrate content at moderate and high N. Contrary to nitrate, water stress increased proline content at moderate and high N. Our results suggest that N metabolism appears to be associated with the tolerance of photosynthesis to water stress in rice via affecting CO2 diffusion, antioxidant capacity, and osmotic adjustment.

  4. Proline accumulation in water-stressed barley leaves in relation to translocation and the nitrogen budget

    International Nuclear Information System (INIS)

    Tully, R.E.; Hanson, A.D.; Nelsen, C.E.

    1979-01-01

    Mobilization of N from leaves of barley (Hordeum vulgare L.) during water stress, and the role of proline as a mobilized species, were examined in plants at the three-leaf stage. The plants responded to water stress by withdrawing about 25% of the total reduced N from the leaf blades via phloem translocation. Most of this N loss was during the first 2 days while translocation of 14 C-photosynthate out of the stressed blade still remained active. Free proline accumulation in the blade was initially slow, and became more rapid during the 2nd day of stress. Although a major free amino acid, proline accounted for only about 5% of the total N(soluble + insoluble) retained in severely stressed blades. When the translocation pathway in water-stressed leaves was interrupted just below the blade by a heat girdle, a cold jacket, or by blade excision, N loss from the blade was prevented and proline began to accumulate rapidly on 1st day of stress. Little free proline accumulated in the blades until after the ability to translocate was lost. Proline was, however, probably not a major species of N translocated during stress, because proline N accumulation in heat-girdled stressed leaves was five times slower than the rate of total N export from intact blades

  5. Accounting for genotype–by-environment interactions and non-additive genetic variation in genomic selection for water-soluble carbohydrate concentration in wheat

    Science.gov (United States)

    Abiotic stress tolerance traits are often complex and recalcitrant targets for conventional breeding improvement in many crop species. This study evaluated the potential of genomic selection to predict water-soluble carbohydrate concentration (WSCC), an important drought tolerance trait, in wheat un...

  6. A multimodal image sensor system for identifying water stress in grapevines

    Science.gov (United States)

    Zhao, Yong; Zhang, Qin; Li, Minzan; Shao, Yongni; Zhou, Jianfeng; Sun, Hong

    2012-11-01

    Water stress is one of the most common limitations of fruit growth. Water is the most limiting resource for crop growth. In grapevines, as well as in other fruit crops, fruit quality benefits from a certain level of water deficit which facilitates to balance vegetative and reproductive growth and the flow of carbohydrates to reproductive structures. A multi-modal sensor system was designed to measure the reflectance signature of grape plant surfaces and identify different water stress levels in this paper. The multi-modal sensor system was equipped with one 3CCD camera (three channels in R, G, and IR). The multi-modal sensor can capture and analyze grape canopy from its reflectance features, and identify the different water stress levels. This research aims at solving the aforementioned problems. The core technology of this multi-modal sensor system could further be used as a decision support system that combines multi-modal sensory data to improve plant stress detection and identify the causes of stress. The images were taken by multi-modal sensor which could output images in spectral bands of near-infrared, green and red channel. Based on the analysis of the acquired images, color features based on color space and reflectance features based on image process method were calculated. The results showed that these parameters had the potential as water stress indicators. More experiments and analysis are needed to validate the conclusion.

  7. Concentration data for anthropogenic organic compounds in ground water, surface water, and finished water of selected community water systems in the United States, 2002-05

    Science.gov (United States)

    Carter, Janet M.; Delzer, Gregory C.; Kingsbury, James A.; Hopple, Jessica A.

    2007-01-01

    combustion-derived compounds; (10) personal care and domestic use products; (11) plant- or animal-derived biochemicals; (12) refrigerants and propellants; and (13) solvents. Source and finished water samples were collected during phase 2 and analyzed for constituents that were detected frequently during phase 1. This report presents concentration data for AOCs in ground water, surface water, and finished water of CWSs sampled for SWQA studies during 2002-05. Specifically, this report presents the analytical results of samples collected during phase 1 including (1) samples from 221 wells that were analyzed for 258 AOCs; (2) monthly samples from 9 surface-water sites that were analyzed for 258 AOCs during phase 1; and (3) samples from a subset of the wells and surface-water sites located in areas with substantial agricultural production that were analyzed for 3 additional pesticides and 16 pesticide degradates. Samples collected during phase 2 were analyzed for selected AOCs that were detected most frequently in source water during phase 1 sampling; analytical results for phase 2 are presented for (1) samples of source water and finished water from 94 wells; and (2) samples of source water and finished water samples that were collected monthly and during selected flow conditions at 8 surface-water sites. Results of quality-assurance/quality-control samples collected for SWQA studies during 2002-05 also are presented.

  8. Selected Factors Determining a Way of Coping with Stress in Type 2 Diabetic Patients

    Directory of Open Access Journals (Sweden)

    Anna Beata Sobol-Pacyniak

    2014-01-01

    Full Text Available Objectives. The aim of the study was to examine factors which determine stress coping styles in type 2 diabetic (T2D patients, with regard to selected demographic variables, clinical diabetes-related variables and selected psychical variables (anxiety level and assessment of depressive disorders. Methods. 50 T2D patients, aged 59.9 ± 10.2 years were assessed by Coping Inventory for Stressful Situations (CISS, Spielberger State-Trait Anxiety Inventory (STAI, and Beck Depression Inventory (BDI. In the statistical analysis simple and multivariable logistic regression models were used. Results. Variables significantly increasing the selection risk of stress coping style different from preferred task-oriented strategy in a simple logistic regression model are: hypoglycemia within three months prior to the research: odds ratio (OR = 6.86 (95% confidence interval (CI 1.25–37.61, taking antidepressants or neuroleptics: OR =15.42 (95% CI 2.42–98.33, severe depression in Beck’s scale: OR = 84.00 (95% CI 6.51–1083.65, high state-anxiety level: OR = 9.60 (95% CI 1.08–85.16, and high trait-anxiety level: OR = 18.40 (95%CI 2.96–114.31, but in a multivariable model, diagnosed depression is the strongest factor: OR = 32.38 (95% CI 4.94–212.13. Conclusions. In T2D patients, the strategy to cope with stress appears to be mostly influenced by psychical predisposition.

  9. Favorable Alleles for Stem Water-Soluble Carbohydrates Identified by Association Analysis Contribute to Grain Weight under Drought Stress Conditions in Wheat

    Science.gov (United States)

    Li, Runzhi; Chang, Xiaoping; Jing, Ruilian

    2015-01-01

    Drought is a major environmental constraint to crop distribution and productivity. Stem water-soluble carbohydrates (WSC) buffer wheat grain yield against conditions unfavorable for photosynthesis during the grain filling stage. In this study, 262 winter wheat accessions and 209 genome-wide SSR markers were collected and used to undertake association analysis based on a mixed linear model (MLM). The WSC in different internodes at three growth stages and 1000-grain weight (TGW) were investigated under four environmental regimes (well-watered, drought stress during the whole growth period, and two levels of terminal drought stress imposed by chemical desiccation under the well-watered and drought stress during the whole growth period conditions). Under diverse drought stress conditions, WSC in lower internodes showed significant positive correlations with TGW, especially at the flowering stage under well-watered conditions and at grain filling under drought stress. Sixteen novel WSC-favorable alleles were identified, and five of them contributed to significantly higher TGW. In addition, pyramiding WSC favorable alleles was not only effective for obtaining accessions with higher WSC, but also for enhancing TGW under different water regimes. During the past fifty years of wheat breeding, WSC was selected incidentally. The average number of favorable WSC alleles increased from 1.13 in the pre-1960 period to 4.41 in the post-2000 period. The results indicate a high potential for using marker-assisted selection to pyramid WSC favorable alleles in improving WSC and TGW in wheat. PMID:25768726

  10. Effects of boron nutrition and water stress on nitrogen fixation, seed δ15N and δ13C dynamics, and seed composition in soybean cultivars differing in maturities.

    Science.gov (United States)

    Bellaloui, Nacer; Mengistu, Alemu

    2015-01-01

    Therefore, the objective of the current research was to investigate the effects of foliar B nutrition on seed protein, oil, fatty acids, and sugars under water stress conditions. A repeated greenhouse experiment was conducted using different maturity group (MG) cultivars. Plants were well-watered with no foliar B (W - B), well-watered with foliar B (W + B), water-stressed with no foliar B (WS - B), and water-stressed with foliar B (WS + B). Foliar B was applied at rate of 0.45 kg · ha(-1) and was applied twice at flowering and at seed-fill stages. The results showed that seed protein, sucrose, fructose, and glucose were higher in W + B treatment than in W - B, WS + B, and WS - B. The increase in protein in W + B resulted in lower seed oil, and the increase of oleic in WS - B or WS + B resulted in lower linolenic acid. Foliar B resulted in higher nitrogen fixation and water stress resulted in seed δ (15)N and δ (13)C alteration. Increased stachyose indicated possible physiological and metabolic changes in carbon and nitrogen pathways and their sources under water stress. This research is beneficial to growers for fertilizer management and seed quality and to breeders to use (15)N/(14)N and (13)C/(12)C ratios and stachyose to select for drought tolerance soybean.

  11. Effects of Boron Nutrition and Water Stress on Nitrogen Fixation, Seed δ15N and δ13C Dynamics, and Seed Composition in Soybean Cultivars Differing in Maturities

    Directory of Open Access Journals (Sweden)

    Nacer Bellaloui

    2015-01-01

    Full Text Available Therefore, the objective of the current research was to investigate the effects of foliar B nutrition on seed protein, oil, fatty acids, and sugars under water stress conditions. A repeated greenhouse experiment was conducted using different maturity group (MG cultivars. Plants were well-watered with no foliar B (W − B, well-watered with foliar B (W + B, water-stressed with no foliar B (WS − B, and water-stressed with foliar B (WS + B. Foliar B was applied at rate of 0.45 kg·ha−1 and was applied twice at flowering and at seed-fill stages. The results showed that seed protein, sucrose, fructose, and glucose were higher in W + B treatment than in W − B, WS + B, and WS − B. The increase in protein in W + B resulted in lower seed oil, and the increase of oleic in WS − B or WS + B resulted in lower linolenic acid. Foliar B resulted in higher nitrogen fixation and water stress resulted in seed δ15N and δ13C alteration. Increased stachyose indicated possible physiological and metabolic changes in carbon and nitrogen pathways and their sources under water stress. This research is beneficial to growers for fertilizer management and seed quality and to breeders to use 15N/14N and 13C/12C ratios and stachyose to select for drought tolerance soybean.

  12. Crop water stress maps for an entire growing season from visible and thermal UAV imagery

    DEFF Research Database (Denmark)

    Hoffmann, Helene; Jensen, Rasmus; Thomsen, Anton

    2016-01-01

    This study investigates whether a water deficit index (WDI) based on imagery from unmanned aerial vehicles (UAVs) can provide accurate crop water stress maps at different growth stages of barley and in differing weather situations. Data from both the early and late growing season are included...... to investigate whether the WDI has the unique potential to be applicable both when the land surface is partly composed of bare soil and when crops on the land surface are senescing. The WDI differs from the more commonly applied crop water stress index (CWSI) in that it uses both a spectral vegetation index (VI...... season because at this stage the remote sensing data represent crop water availability to a greater extent than they do in the early growing season, and because the WDI accounts for areas of ripe crops that no longer have the same need for irrigation. WDI maps can potentially serve as water stress maps...

  13. The Response of Rice Root to Time Course Water Deficit Stress-Two Dimensional Electrophoresis Approach

    Directory of Open Access Journals (Sweden)

    Mahmood Toorchi

    2015-11-01

    Full Text Available Rice (Oryza sativa L. is the staple food of more than half of the population worldwide. Water deficit stress is one of the harsh limiting factors for successful production of crops. Rice during its growing period comes a cross different environmental hazards like drought stress. Recent advance in molecular physiology are promising for more progress in increasing rice yield by identification of novel candidate proteins for drought tolerance. To investigate the effect of water deficit on rice root protein expression pattern, an experiment was conducted in completely randomize design with four replications. With holding water for 24, 36 and 48 hours along with control constituted the experimental treatments. The experiment was conducted in growth chamber under controlled condition and root samples, after stress imposition, were harvested for two-dimensional electrophorese (2-DE. Proteome analysis of root tissue by 2-DE indicated that out of 135 protein spots diagnosed by Coomassie blue staining, 14 spots showed significant expression change under water deficit condition, seven of them at 1% and the other seven at 5% probability levels. Differentially changed proteins were taken into account for search in data bank using isoelectric point and molecular weight to identify the most probable responsive proteins. Up- regulation of ferredoxin oxidoreductase at first 24 hour after applying stress indicates the main role of this protein in reducing water deficit stress effects. On the other hand ribosomal proteins, GAP-3 and ATP synthase were down regulated under water deficit stress. Fructose 1,6-bisphosphate aldolase, glucose- 6-phosphate dehydrogenase and chitinase down regulated up to 36 h of stress imposition but, were later up- regulated by prolonging stress up to 48 h. It could be inferred the plant tries to decrease the effect of oxidative stress.

  14. Does morphological and anatomical plasticity during the vegetative stage make wheat more tolerant of water deficit stress than rice?

    NARCIS (Netherlands)

    Kadam, N.N.; Yin, X.; Bindraban, P.S.; Struik, P.C.; Jagadish, K.S.V.

    2015-01-01

    Water scarcity and the increasing severity of water deficit stress are major challenges to sustaining irrigated rice (Oryza sativa) production. Despite the technologies developed to reduce the water requirement, rice growth is seriously constrained under water deficit stress compared with other

  15. Effect of Mulch and Water Stress on Some Physiological Traits, Yield Components and Grain Yield of Red Kidney bean (Phaseolus vulgaris L.

    Directory of Open Access Journals (Sweden)

    R Amini

    2016-02-01

    that of cv. Akhtar. This result could be related to the longer growth period of cv. Naz than cv. Akhtar. The effects of water stress, mulch, cultivar and the all interaction effects were significant on red kidney bean grain yield. The mulch application increased the grain yield by 18%. The effect of water stress  mulch cultivar indicated that the cv. Akhatr in full irrigation treatment and application of straw mulch had the highest grain yield (3135 kg ha-1. Also the cv. Naz in water stress treatment and application of without mulch application had the lowest grain yield (1340 kg ha-1. The cv. Akhtar had a bush type growth pattern and a lower green cover than cv. Naz, therefore mulch application on the soil surface could increase the available water for red kidney bean. Conclusions At water limitation conditions by mulch application, the available water, yield components and grain yield of red kidney bean could be increased. Under drought and aridity conditions, field management practices such as selecting high-yielding cultivars and reducing soil evaporation by using of mulch increased the grain yield especially in water limitation condition. Investigating the response of other common bean cultivars to water stress and mulch could be effective for identifying the common bean cultivars with high grain yield at water stress condition with mulch application that is consistent with sustainable agriculture.

  16. Effect of Phosphorus Fertilizer and Water Stress on Protein and Phenolic Contents in Cotton (Gossypium Hirsutum L.)

    International Nuclear Information System (INIS)

    Abbas, Z.; Muhammad, S.; Murtaza, G.; Ahmad, I.; Shakeel, A.; Islam, M.; Ahmad, M.; Abdullah, M.

    2015-01-01

    Crop quality and production are affected by various fertilizers and water stress. In present research, the response of cotton variety CIM-496 to water stress and phosphorus fertilizer was investigated. Samples were collected after 90 days of planting. Kjeldahl method and thin layer chromatography (TLC) were used for the quantitative and qualitative analysis of total protein and phenolic compounds, respectively. Proteins were greatly affected by fertilizer treatment and water stress, but phenolic compounds remained unchanged upon fertilizer treatment. However, they were greatly affected by irrigation and water stress. Crop treated with 100 kg ha/sup -1/ P/sub 2/O/sub 5/ under water stress maintained high protein content as compared to unfertilized and no water stress treatments. However, phenolic compounds were found higher in fully irrigated plants as compared to water stress ones. Fertilizer treatments had no considerable effect on phenolic compounds. (author)

  17. Water stress indices for the sugarcane crop on different irrigated surfaces

    Directory of Open Access Journals (Sweden)

    Rodrigo G. Brunini

    Full Text Available ABSTRACT Sugarcane (Saccharum officinarum L. is a crop of vital importance to Brazil, in the production of sugar and ethanol, power generation and raw materials for various purposes. Strategic information such as topography and canopy temperature can provide management technologies accessible to farmers. The objective of this study was to determine water stress indices for sugarcane in irrigated areas, with different exposures and slopes. The daily water stress index of the plants and the water potential in the soil were evaluated and the production system was analyzed. The experiment was carried out in an “Experimental Watershed”, using six surfaces, two horizontal and the other ones with 20 and 40% North and South exposure slopes. Water stress level was determined by measuring the temperatures of the vegetation cover and the ambient air. Watering was carried out using a drip irrigation system. The results showed that water stress index of sugarcane varies according to exposure and slope of the terrain, while areas whose water stress index was above 5.0 oC had lower yield values.

  18. Impact of water-deficit stress on tritrophic interactions in a wheat-aphid-parasitoid system.

    Directory of Open Access Journals (Sweden)

    Syed Suhail Ahmed

    Full Text Available Increasing temperature and CO2 concentrations can alter tritrophic interactions in ecosystems, but the impact of increasingly severe drought on such interactions is not well understood. We examined the response of a wheat-aphid-parasitoid system to variation in water-deficit stress levels. Our results showed that arid area clones of the aphid, Sitobion avenae (Fabricius, tended to have longer developmental times compared to semiarid and moist area clones, and the development of S. avenae clones tended to be slower with increasing levels of water-deficit. Body sizes of S. avenae clones from all areas decreased with increasing water-deficit levels, indicating their declining adaptation potential under drought. Compared to arid area clones, moist area clones of S. avenae had a higher frequency of backing under severe water stress only, but a higher frequency of kicking under well-watered conditions only, suggesting a water-deficit level dependent pattern of resistance against the parasitoid, Aphidius gifuensis (Ashmead. The number of S. avenae individuals attacked by the parasitoid in 10 min showed a tendency to decrease with increasing water-deficit levels. Clones of S. avenae tended to have lower parasitism rates under treatments with higher water-deficit levels. The development of the parasitoid tended to be slower under higher levels of water-deficit stress. Thus, the bottom-up effects of water-deficit stressed plants were negative on S. avenae. However, the top-down effects via parasitoids were compromised by water-deficit, which could favor the growth of aphid populations. Overall, the first trophic level under water-deficit stress was shown to have an indirect and negative impact on the third trophic level parasitoid, suggesting that parasitoids could be increasingly vulnerable in future warming scenarios.

  19. Spatial and temporal variations of selected heavy metals in water ...

    African Journals Online (AJOL)

    Mr HMM Mzimela

    2014-08-01

    Aug 1, 2014 ... Health Organization (WHO) recommended limit for drinking water (1.5 mg/L). This suggests ... Water sampling. Eleven thermal springs were purposively sampled in order to study their chemistry. Sampling was done in December, 2007. Grab ..... precipitates out and settles on the pipelines (Purschel,. 2006).

  20. Bromine and water quality – Selected aspects and future perspectives

    International Nuclear Information System (INIS)

    Winid, Bogumiła

    2015-01-01

    Bromine is a microelement present in waters, both in inorganic and in a wide range of organic compounds, though at lower concentrations. Typically, concentrations of organobromine compounds in waters are several orders of magnitude lower than of bromides. Two issues are addressed in the paper: the influence of bromides on the quality of treated waters and organobromines as contaminants of natural waters. Bromide presence in treated water gives rise to formation of potentially mutagenic disinfection by-products (DBPs). Registered amounts of DBPs in potable waters, exceeding the admissible levels, and the published data on DBPs in waters used for leisure and recreation activities, clearly indicate the health risk. Major sources are identified and registered concentrations of EDB, DBCB, methyl bromide, bromacil and PBDEs in the aquatic environment are summarized. The effects of bromide on DBPs formation and numerous examples of organobromine contamination of the aquatic environment indicate that the presence of bromides and organobromine compounds in the aquatic environment will have to be given more consideration, for several reasons. Firstly, larger amounts of bromide are present in saline and contaminated waters and the proportion of such waters being handled is increasing. Similarly, the processes of water purification, treatment and disinfection are now playing a major role. Secondly, emissions from manufacturing of bromine-containing materials growing, due to, inter alia, intensive development of the electronic industry and the plastic manufacturing sector. Thirdly, bromine compounds are also used as medicine ingredients. There is now a growing awareness of the presence of pharmaceuticals in the aquatic environment. Fourth, low bromide concentrations in hypergene zones may be modified in the future, partly because of the climate changes, which may give rise to difficulties with water treatment systems. Water quality standards having relevance to water used for

  1. Limited irrigation research and infrared thermometry for detecting water stress

    Science.gov (United States)

    The USDA-ARS Limited Irrigation Research Farm, located outside of Greeley Colorado, is an experiment evaluating management perspectives of limited irrigation water. An overview of the farm systems is shown, including drip irrigation systems, water budgeting, and experimental design, as well as preli...

  2. Hydrology and water quality characteristics of a stressed lotic ...

    African Journals Online (AJOL)

    The hydrology and water quality of Aiba stream were investigated from November 2012 to April 2013 on monthly basis. This was with a view to assessing the status of the stream sequel to its last study which indicated a poor physico-chemical water quality. Four sampling stations were established for the study along the ...

  3. Speech perception in older listeners with normal hearing:conditions of time alteration, selective word stress, and length of sentences.

    Science.gov (United States)

    Cho, Soojin; Yu, Jyaehyoung; Chun, Hyungi; Seo, Hyekyung; Han, Woojae

    2014-04-01

    Deficits of the aging auditory system negatively affect older listeners in terms of speech communication, resulting in limitations to their social lives. To improve their perceptual skills, the goal of this study was to investigate the effects of time alteration, selective word stress, and varying sentence lengths on the speech perception of older listeners. Seventeen older people with normal hearing were tested for seven conditions of different time-altered sentences (i.e., ±60%, ±40%, ±20%, 0%), two conditions of selective word stress (i.e., no-stress and stress), and three different lengths of sentences (i.e., short, medium, and long) at the most comfortable level for individuals in quiet circumstances. As time compression increased, sentence perception scores decreased statistically. Compared to a natural (or no stress) condition, the selectively stressed words significantly improved the perceptual scores of these older listeners. Long sentences yielded the worst scores under all time-altered conditions. Interestingly, there was a noticeable positive effect for the selective word stress at the 20% time compression. This pattern of results suggests that a combination of time compression and selective word stress is more effective for understanding speech in older listeners than using the time-expanded condition only.

  4. water stress mediated changes in growth, physiology and secondary metabolites of desi ajwain (trachyspermum ammi l.)

    International Nuclear Information System (INIS)

    Azhar, N.; Hussain, B.; Abbasi, K.Y.

    2011-01-01

    Biotic and abiotic stresses exert a considerable influence on the production of several secondary metabolites in plants; water stress is one of the most important abiotic stress factors. This study was carried out to elucidate the effect of drought stress on growth, physiology and secondary metabolite production in desi ajwain (Trachyspermum ammi L.). Plants were grown in pots and three drought levels (100%, 80% and 60%) of field capacity were created. The experiment was laid out in complete randomized design (CRD) with three replicates. Data on growth, physiological and biochemical parameters were recorded and analyzed statistically. Physiological parameters like transpiration rate and stomatal conductance decreased concentration increased. The photosynthetic rate showed significantly with increasing water stress levels, but internal CO/sub 2/ non-significant reduction from 100% field capacity to 80% field capacity but increased at 60% field capacity. Growth parameters including plant height, herb fresh and dry weights were reduced significantly with increasing stress levels, while total phenolic contents and chlorophyll contents increased under water stress conditions. These results suggest that cultivation of medicinal plants like desi ajwain under drought stress could enhance the production of secondary metabolites. (author)

  5. Movement of Abscisic Acid into the Apoplast in Response to Water Stress in Xanthium strumarium L.

    Science.gov (United States)

    Cornish, K; Zeevaart, J A

    1985-07-01

    The effect of water stress on the redistribution of abcisic acid (ABA) in mature leaves of Xanthium strumarium L. was investigated using a pressure dehydration technique. In both turgid and stressed leaves, the ABA in the xylem exudate, the ;apoplastic' ABA, increased before ;bulk leaf' stress-induced ABA accumulation began. In the initially turgid leaves, the ABA level remained constant in both the apoplast and the leaf as a whole until wilting symptoms appeared. Following turgor loss, sufficient quantities of ABA moved into the apoplast to stimulate stomatal closure. Thus, the initial increase of apoplastic ABA may be relevant to the rapid stomatal closure seen in stressed leaves before their bulk leaf ABA levels rise.Following recovery from water stress, elevated levels of ABA remained in the apoplast after the bulk leaf contents had returned to their prestress values. This apoplastic ABA may retard stomatal reopening during the initial recovery period.

  6. Responses to water stress of gas exchange and metabolites in Eucalyptus and Acacia spp.

    Science.gov (United States)

    Warren, Charles R; Aranda, Ismael; Cano, F Javier

    2011-10-01

    Studies of water stress commonly examine either gas exchange or leaf metabolites, and many fail to quantify the concentration of CO₂ in the chloroplasts (C(c)). We redress these limitations by quantifying C(c) from discrimination against ¹³CO₂ and using gas chromatography-mass spectrometry (GC-MS) for leaf metabolite profiling. Five Eucalyptus and two Acacia species from semi-arid to mesic habitats were subjected to a 2 month water stress treatment (Ψ(pre-dawn) = -1.7 to -2.3 MPa). Carbohydrates dominated the leaf metabolite profiles of species from dry areas, whereas organic acids dominated the metabolite profiles of species from wet areas. Water stress caused large decreases in photosynthesis and C(c), increases in 17-33 metabolites and decreases in 0-9 metabolites. In most species, fructose, glucose and sucrose made major contributions to osmotic adjustment. In Acacia, significant osmotic adjustment was also caused by increases in pinitol, pipecolic acid and trans-4-hydroxypipecolic acid. There were also increases in low-abundance metabolites (e.g. proline and erythritol), and metabolites that are indicative of stress-induced changes in metabolism [e.g. γ-aminobutyric acid (GABA) shunt, photorespiration, phenylpropanoid pathway]. The response of gas exchange to water stress and rewatering is rather consistent among species originating from mesic to semi-arid habitats, and the general response of metabolites to water stress is rather similar, although the specific metabolites involved may vary. © 2011 Blackwell Publishing Ltd.

  7. The Influence of Water Sorption of Dental Light-Cured Composites on Shrinkage Stress

    Directory of Open Access Journals (Sweden)

    Kinga Bociong

    2017-09-01

    Full Text Available The contraction stress generated during the photopolymerization of resin dental composites is the major disadvantage. The water sorption in the oral environment should counteract the contraction stress. The purpose was to evaluate the influence of the water sorption of composite materials on polymerization shrinkage stress generated at the restoration-tooth interface. The following materials were tested: Filtek Ultimate, Gradia Direct LoFlo, Heliomolar Flow, Tetric EvoCeram, Tetric EvoCeram Bulk Fill, Tetric EvoFlow, Tetric EvoFlow Bulk Fill, X-tra Base, Venus BulkFil, and Ceram.X One. The shrinkage stress was measured immediately after curing and after: 0.5 h, 24 h, 72 h, 96 h, 168 h, 240 h, 336 h, 504 h, 672 h, and 1344 h by means of photoelastic study. Moreover, water sorption and solubility were evaluated. Material samples were weighted on scale in time intervals to measure the water absorbency and the dynamic of this process. The tested materials during polymerization generated shrinkage stresses ranging from 6.3 MPa to 12.5 MPa. Upon water conditioning (56 days, the decrease in shrinkage strain (not less than 48% was observed. The decrease in value stress in time is material-dependent.

  8. Liquid organomineral fertilizer containing humic substances on soybean grown under water stress

    Directory of Open Access Journals (Sweden)

    Marcelo R. V. Prado

    2016-05-01

    Full Text Available ABSTRACT This study evaluated the effect of an organomineral fertilizer enriched with humic substances on soybean grown under water stress. The experiment was performed in a greenhouse using a Red Latosol (Oxisol with adequate fertility as substrate, in which soybean plants were cultivated with and without water stress. The experimental design was randomized blocks, in a 2 x 5 factorial scheme (two moisture levels and five fertilizer doses: 0, 1, 2, 4 and 8 mL dm-3, totaling 10 treatments, with four replicates. The organomineral fertilizer was applied in the soil 21 days after plant emergence and the water regimes were established one week thereafter. The fertilizer was not able to attenuate the effects of water stress, reducing soybean grain yield by more than 50% compared with plants cultivated under no stress. Fertilizer doses caused positive response on soybean nutrition and grain yield and, under water stress condition, the most efficient dose was 5.4 mL dm-3. There were lower leaf concentrations of nitrogen, phosphorus and potassium and higher concentrations of sulfur in plants under stress. Humic substances favor the absorption of micronutrients.

  9. Investigation of selected water quality parameters in the Amargosa Drainage Basin

    International Nuclear Information System (INIS)

    Elliott, B.

    1982-08-01

    The purpose of this investigation was to determine whether Amargoso Desert water quality meets established federal drinking water standards. Samples were collected at selected drinking water supply sites and were analyzed for inorganic chemical constituents and radioactivity. The findings indicate that no concentrations of radioactivity in the drinking water exceeded the standards; however, some naturally occurring chemical constituent analysis indicate concentrations above federal drinking water standards. 18 references, 3 figures, 4 tables. (MF)

  10. Oroxin B selectively induces tumor-suppressive ER stress and concurrently inhibits tumor-adaptive ER stress in B-lymphoma cells for effective anti-lymphoma therapy

    International Nuclear Information System (INIS)

    Yang, Ping; Fu, Shilong; Cao, Zhifei; Liao, Huaidong; Huo, Zihe; Pan, Yanyan; Zhang, Gaochuan; Gao, Aidi; Zhou, Quansheng

    2015-01-01

    Cancer cells have both tumor-adaptive and -suppressive endoplasmic reticulum (ER) stress machineries that determine cell fate. In malignant tumors including lymphoma, constant activation of tumor-adaptive ER stress and concurrent reduction of tumor-suppressive ER stress favors cancer cell proliferation and tumor growth. Current ER stress-based anti-tumor drugs typically activate both tumor-adaptive and -suppressive ER stresses, resulting in low anti-cancer efficacy; hence, selective induction of tumor-suppressive ER stress and inhibition of tumor-adaptive ER stress are new strategies for novel anti-cancer drug discovery. Thus far, specific tumor-suppressive ER stress therapeutics have remained absent in clinical settings. In this study, we explored unique tumor-suppressive ER stress agents from the traditional Chinese medicinal herb Oroxylum indicum, and found that a small molecule oroxin B selectively induced tumor-suppressive ER stress in malignant lymphoma cells, but not in normal cells, effectively inhibited lymphoma growth in vivo, and significantly prolonged overall survival of lymphoma-xenografted mice without obvious toxicity. Mechanistic studies have revealed that the expression of key tumor-adaptive ER-stress gene GRP78 was notably suppressed by oroxin B via down-regulation of up-stream key signaling protein ATF6, while tumor-suppressive ER stress master gene DDIT3 was strikingly activated through activating the MKK3-p38 signaling pathway, correcting the imbalance between tumor-suppressive DDIT3 and tumor-adaptive GRP78 in lymphoma. Together, selective induction of unique tumor-suppressive ER stress and concurrent inhibition of tumor-adaptive ER stress in malignant lymphoma are new and feasible approaches for novel anti-lymphoma drug discovery and anti-lymphoma therapy. - Highlights: • Oroxin B selectively induces tumor-suppressive ER stress in B-lymphoma cells. • Oroxin B significantly prolonged overall survival of lymphoma-xenografted mice.

  11. Oroxin B selectively induces tumor-suppressive ER stress and concurrently inhibits tumor-adaptive ER stress in B-lymphoma cells for effective anti-lymphoma therapy

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ping; Fu, Shilong; Cao, Zhifei; Liao, Huaidong; Huo, Zihe; Pan, Yanyan; Zhang, Gaochuan; Gao, Aidi; Zhou, Quansheng, E-mail: zhouqs@suda.edu.cn

    2015-10-15

    Cancer cells have both tumor-adaptive and -suppressive endoplasmic reticulum (ER) stress machineries that determine cell fate. In malignant tumors including lymphoma, constant activation of tumor-adaptive ER stress and concurrent reduction of tumor-suppressive ER stress favors cancer cell proliferation and tumor growth. Current ER stress-based anti-tumor drugs typically activate both tumor-adaptive and -suppressive ER stresses, resulting in low anti-cancer efficacy; hence, selective induction of tumor-suppressive ER stress and inhibition of tumor-adaptive ER stress are new strategies for novel anti-cancer drug discovery. Thus far, specific tumor-suppressive ER stress therapeutics have remained absent in clinical settings. In this study, we explored unique tumor-suppressive ER stress agents from the traditional Chinese medicinal herb Oroxylum indicum, and found that a small molecule oroxin B selectively induced tumor-suppressive ER stress in malignant lymphoma cells, but not in normal cells, effectively inhibited lymphoma growth in vivo, and significantly prolonged overall survival of lymphoma-xenografted mice without obvious toxicity. Mechanistic studies have revealed that the expression of key tumor-adaptive ER-stress gene GRP78 was notably suppressed by oroxin B via down-regulation of up-stream key signaling protein ATF6, while tumor-suppressive ER stress master gene DDIT3 was strikingly activated through activating the MKK3-p38 signaling pathway, correcting the imbalance between tumor-suppressive DDIT3 and tumor-adaptive GRP78 in lymphoma. Together, selective induction of unique tumor-suppressive ER stress and concurrent inhibition of tumor-adaptive ER stress in malignant lymphoma are new and feasible approaches for novel anti-lymphoma drug discovery and anti-lymphoma therapy. - Highlights: • Oroxin B selectively induces tumor-suppressive ER stress in B-lymphoma cells. • Oroxin B significantly prolonged overall survival of lymphoma-xenografted mice.

  12. Water stress mitigates the negative effects of ozone on photosynthesis and biomass in poplar plants.

    Science.gov (United States)

    Gao, Feng; Catalayud, Vicent; Paoletti, Elena; Hoshika, Yasutomo; Feng, Zhaozhong

    2017-11-01

    Tropospheric ozone (O 3 ) pollution frequently overlaps with drought episodes but the combined effects are not yet understood. We investigated the physiological and biomass responses of an O 3 sensitive hybrid poplar clone ('546') under three O 3 levels (charcoal-filtered ambient air, non-filtered ambient air (NF), and NF plus 40 ppb) and two watering regimes (well-watered (WW) and reduced watering (RW), i.e. 40% irrigation) for one growing season. Water stress increased chlorophyll and carotenoid contents, protecting leaves from pigment degradation by O 3 . Impairment of photosynthesis by O 3 was also reduced by stomatal closure due to water stress, which preserved light-saturated CO 2 assimilation rate, and the maximum carboxylation efficiency. Water stress increased water use efficiency of the leaves while O 3 decreased it, showing significant interactions. Effects were more evident in older leaves than in younger leaves. Water stress reduced biomass production, but the negative effects of O 3 were less in RW than in WW for total biomass per plant. A stomatal O 3 flux-based dose-response relationship was parameterized considering water stress effects, which explained biomass losses much better than a concentration-based approach. The O 3 critical level of Phytotoxic Ozone Dose over a threshold of 7 nmol O 3 .m -2 .s -1 (POD 7 ) for a 4% biomass loss in this poplar clone under different water regimes was 4.1 mmol m -2 . Our results suggest that current O 3 levels in most parts of China threaten poplar growth and that interaction with water availability is a key factor for O 3 risk assessment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Spectral entropy as a mean to quantify water stress history for natural vegetation and irrigated agriculture in a water-stressed tropical environment

    Science.gov (United States)

    Kim, Y.; Johnson, M. S.

    2017-12-01

    Spectral entropy (Hs) is an index which can be used to measure the structural complexity of time series data. When a time series is made up of one periodic function, the Hs value becomes smaller, while Hs becomes larger when a time series is composed of several periodic functions. We hypothesized that this characteristic of the Hs could be used to quantify the water stress history of vegetation. For the ideal condition for which sufficient water is supplied to an agricultural crop or natural vegetation, there should be a single distinct phenological cycle represented in a vegetation index time series (e.g., NDVI and EVI). However, time series data for a vegetation area that repeatedly experiences water stress may include several fluctuations that can be observed in addition to the predominant phenological cycle. This is because the process of experiencing water stress and recovering from it generates small fluctuations in phenological characteristics. Consequently, the value of Hs increases when vegetation experiences several water shortages. Therefore, the Hs could be used as an indicator for water stress history. To test this hypothesis, we analyzed Moderate Resolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index (NDVI) data for a natural area in comparison to a nearby sugarcane area in seasonally-dry western Costa Rica. In this presentation we will illustrate the use of spectral entropy to evaluate the vegetative responses of natural vegetation (dry tropical forest) and sugarcane under three different irrigation techniques (center pivot irrigation, drip irrigation and flood irrigation). Through this comparative analysis, the utility of Hs as an indicator will be tested. Furthermore, crop response to the different irrigation methods will be discussed in terms of Hs, NDVI and yield.

  14. Evaluation of 10 wheat cultivars under water stress at Moghan (Iran ...

    African Journals Online (AJOL)

    Hami

    2011-09-14

    Sep 14, 2011 ... Accepted 20 May, 2011. Water deficit is one of the main abiotic factors that affect yield and yield component of wheat planted in ... evaluate the effects of water stress on seed yield and yield components of ten wheat cultivars and lines that differ in .... Analysis of variance is presented in Table 2. According to.

  15. Physiological and biochemical changes in Matricaria chamomilla induced by Pseudomonas fluorescens and water deficit stress

    Directory of Open Access Journals (Sweden)

    Hamid MOHAMMADI

    2018-04-01

    Full Text Available Environmental stresses and rhizosphere microorganisms affect growth parameters and accumulation of active ingredients especially in plants with medicinal properties. The present study examined the effects of chamomile (Matricaria chamomilla L. seedling inoculation with Pseudomonas fluorescens PF-135 strain on its growth parameters, photosynthetic pigments, proline, malondialdehyde (MDA, and hydrogen peroxide (H2O2 content, and essential oil concentration at both regular watering and water deficit experiments. Based on the obtained results, water deficit stress reduced root dry mass, and flower fresh and dry mass as well. However, amount of H2O2 and MDA in root and shoot tissues were considerably lower in inoculated plants compared to non-inoculated ones under both normal watering and water deficit regimes. It indicates that lipid peroxidation and production of reactive oxygen species has been diminished in inoculated plants. Also, essential oil content in inoculated plants significantly increased compared with that of non-inoculated ones under water deficit stress condition. It can be concluded that P. fluorescens PF-135 strain has an outstanding potential to alleviate adverse effects of water deficit on plant growth, and hence can be used as an excellent PGPR in order to boost chamomile productivity especially under water deficit stress condition.

  16. Water deficit stress effects on corn (Zea mays, L.) root: shoot ratio

    Science.gov (United States)

    A study was conducted at Akron, CO, USA, on a Weld silt loam in 2004 to quantify the effects of water deficit stress on corn (Zea mays, L.) root and shoot biomass. Corn plants were grown under a range of soil bulk density and water conditions caused by previous tillage, crop rotation, and irrigation...

  17. Estimating maize water stress by standard deviation of canopy temperature in thermal imagery

    Science.gov (United States)

    A new crop water stress index using standard deviation of canopy temperature as an input was developed to monitor crop water status. In this study, thermal imagery was taken from maize under various levels of deficit irrigation treatments in different crop growing stages. The Expectation-Maximizatio...

  18. Leaf temperature of maize and crop water stress index with variable irrigation and nitrogen supply

    Science.gov (United States)

    Water scarcity due to changing climate, population growth, and economic development is a major threat to the sustainability of irrigated agriculture in the Western United States and other regions around the world. Water stress indices based on crop canopy temperature can be useful for assessing plan...

  19. Responses of growth and primary metabolism of water-stressed barley roots to rehydration

    Science.gov (United States)

    Barley seedlings [Hordeum vulgare L. Brant] were grown in pots in controlled environment chambers and drought treatments were imposed 11 days after sowing. Soil water content decreased from 92% to 10% after an additional 14 days of water stress. Shoot and root growth ceased after 4 and 9 days of wat...

  20. Effects of Water Stress on Photosynthesis and Chlorophyll Fluorescence of the Sugar Beet

    Directory of Open Access Journals (Sweden)

    HAN Kai-hong

    2015-10-01

    Full Text Available To investigate the effect of water stress and rewatering on sugar beet yield and its corresponding photosynthetic parameters, and to provide the basis of water management for the sugar beet fields, pool experiments in an artificial proof canopy were set up to observe changes of beet net photosynthetic rate(Pn, transpiration rate(Tr, water use efficiency(WUE and stomatal limitation (Ls, intercellular CO2 oncentration(Ci, and PSⅡ maximum quantum yield(Fv/Fm. The results indicated that the diurnal variation of Tr and Pn in CK treatment (whole growth period replenishment at different times near "unimodal" type; and water shortage treatments presented "twin peaks" change. Diurnal transpiration capacity(DTC under water stress at sugar accumulation stage reduced by 70.16%~74.81% and diurnal photosynthetic capacity(DPC was 63.48%~69.96% lower than that of CK, while diurnal water use efficiency(WUEd increased by 19.28%~22.39%. Rehydration helped Tr and Pn recovery, but did not reach unstressed levels. Ls changes under extremely dry environment had a midday trough "twin peaks" feature, and Ci was at "double-dip" in consistent with the timing of Ls; Water stress inhibited and inactivated photochemical reaction center of midday PSⅡ. Water stress led to irreversible decrease in the Pn and Tr, and prolonged the Pn inefficient period, which become the important factor of influencing the sugar beet yield.

  1. Evaluation of 10 wheat cultivars under water stress at Moghan (Iran ...

    African Journals Online (AJOL)

    Water deficit is one of the main abiotic factors that affect yield and yield component of wheat planted in arid and semi-arid regions. This study was conducted to evaluate the effect of water stress on wheat yield and yield component during 2008 at Moghan conditions. The objective of this study was to evaluate the effects of ...

  2. Physiological behaviors and recovery responses of four galician grapevine (Vitis vinifera L. cultivars under water stress

    Directory of Open Access Journals (Sweden)

    Islam M. T.

    2012-11-01

    Full Text Available Gas exchange parameters and chlorophyll fluorescence of four pot grown Galician grapevines (Vitis vinifera L. cv. Albariño, Brancellao, Godello and Treixadura were examined under different levels of water stress in greenhouse. After extreme stress, gas exchange recovery responses were evaluated. Average ΨPD for control and stressed plants were -0.4MPa and -1.45MPa respectively. All varieties showed gradual declining of all gas exchange parameters (gs, E and A with increasing of stress periods. Under stressed conditions, Albariño and Godello showed higher CO2 assimilation rate. At the end of stress period leaf defoliation was found in Albariño and Brancellao. Gas exchange recovery was higher for both Godello and Treixadura. A better response of auxiliary bud recovery was present in Albariño than in Brancellao. Close correlations between water stress and gas exchange parameters were found and it varies on genotype. Albariño, Godello and Treixadura followed same diurnal patterns of gas exchange rate for control and stressed plant respectively. Diurnal pattern of CO2 assimilation rate of all tested varieties followed gs and E. Only Brancellao showed treatment effect on mid-day Fv/Fm. Among four varieties photoinhibition was only found in Brancellao. At stressed condition physiological responses of grapevines were genotype depended.

  3. Climatic and anthropogenic changes in Western Switzerland: Impacts on water stress.

    Science.gov (United States)

    Milano, Marianne; Reynard, Emmanuel; Köplin, Nina; Weingartner, Rolf

    2015-12-01

    Recent observed hydro-climatic changes in mountainous areas are of concern as they may directly affect capacity to fulfill water needs. The canton of Vaud in Western Switzerland is an example of such a region as it has experienced water shortage episodes during the past decade. Based on an integrated modeling framework, this study explores how hydro-climatic conditions and water needs could evolve in mountain environments and assesses their potential impacts on water stress by the 2060 horizon. Flows were simulated based on a daily semi-distributed hydrological model. Future changes were derived from Swiss climate scenarios based on two regional climate models. Regarding water needs, the authorities of the canton of Vaud provided a population growth scenario while irrigation and livestock trends followed a business-as-usual scenario. Currently, the canton of Vaud experiences moderate water stress from June to August, except in its Alpine area where no stress is noted. In the 2060 horizon, water needs could exceed 80% of the rivers' available resources in low- to mid-altitude environments in mid-summer. This arises from the combination of drier and warmer climate that leads to longer and more severe low flows, and increasing urban (+40%) and irrigation (+25%) water needs. Highlighting regional differences supports the development of sustainable development pathways to reduce water tensions. Based on a quantitative assessment, this study also calls for broader impact studies including water quality issues. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. The response of winter wheat to water stress and nitrogen fertilizer use efficiency

    International Nuclear Information System (INIS)

    Wang, F.; Qi, M.; Wang, H.; Changjiu, Z.

    1995-01-01

    The response of winter wheat to water stress imposed at different crop growth stages by deficit irrigation and fertilizer use under several schemes of irrigation were evaluated on fine sandy soil and sand loam soil. The results showed that according to grain yield response factor K, the order of sensitive growth stages of winter wheat to water stress in decreasing sequence were booting to flowering ( K= 0.90), winter afterward to booting ( K= 0.69), flowering to milking ( K= 0.44) and milking to ripening ( K= 0.25). Field water efficiency would get 16.7 kg/mm.ha when no water stress in growth period, and when water stress has occurred in some growth stages, the value of it decreased by 5 - 20 percent. It was also found that high fertilizer application rate without split application would not significantly influence the yield on fine sandy soil. But schedule of irrigation affected the translocation of nitrogen in the plant. When water stress occurred in later growth stage, the ratio of NUE in gain to straw decreased, and fertilizer was available for crop only about one month after fertilizer application, excessive fertilizer rate would result in decrease of NUE by leaching of nitrogen in sandy soil. Total recovery of fertilizer at harvest was half amount of application. 6 refs; 10 tabs; ( author)

  5. [Effects of water stress and temperature on gas exchange and chlorophyll fluorescence of Sinocalycanthus chinensis leaves].

    Science.gov (United States)

    Ke, Shi-sheng; Jin, Ze-xin

    2008-01-01

    Sinocalycanthus chinensis is an endangered species in Sinocalycanthus, and only distributed in Zhejiang Province of China. This paper studied the photosynthetic responses of 2-year-old pot-cultured S. chinensis to different levels of water stress and temperature. The results indicated that under mild and moderate water stress, the net photosynthetic rate (Pn) of S. chinensis leaves was decreased to 92.3% and 74.3% of the control, respectively, which was mainly attributed to stomatal limitation; and under severe water stress, the Pn was decreased to 44.4% of the control, which might be mainly linked to non-stomatal limitation. The appropriate temperature for S. chinensis photosynthesis was from 20 degrees C to 28 degrees C. At 39 degrees C, the Pn, water use efficiency (WUE), and maximal photochemistry efficiency (Fv/Fm) were decreased significantly, while the dark respiration rate (Rd) and transpiration rate (Tr) were enhanced significantly. With increasing water stress and temperature, some photosynthetic parameters including light saturation point (LSP), apparent quantum yield (AQY) and maximal CO2 assimilation rate (Pmax) decreased to certain extents, while light compensation point (LCP) increased, suggesting that both severe water stress and higher temperature were the important environmental factors affecting the survival of S. chinensis.

  6. Interactions between biochar and mycorrhizal fungi in a water-stressed agricultural soil.

    Science.gov (United States)

    Mickan, Bede S; Abbott, Lynette K; Stefanova, Katia; Solaiman, Zakaria M

    2016-08-01

    Biochar may alleviate plant water stress in association with arbuscular mycorrhizal (AM) fungi but research has not been conclusive. Therefore, a glasshouse experiment was conducted to understand how interactions between AM fungi and plants respond to biochar application under water-stressed conditions. A twin chamber pot system was used to determine whether a woody biochar increased root colonisation by a natural AM fungal population in a pasture soil ('field' chamber) and whether this was associated with increased growth of extraradical AM fungal hyphae detected by plants growing in an adjacent ('bait') chamber containing irradiated soil. The two chambers were separated by a mesh that excluded roots. Subterranean clover was grown with and without water stress and harvested after 35, 49 and 63 days from each chamber. When biochar was applied to the field chamber under water-stressed conditions, shoot mass increased in parallel with mycorrhizal colonisation, extraradical hyphal length and shoot phosphorus concentration. AM fungal colonisation of roots in the bait chamber indicated an increase in extraradical mycorrhizal hyphae in the field chamber. Biochar had little effect on AM fungi or plant growth under well-watered conditions. The biochar-induced increase in mycorrhizal colonisation was associated with increased growth of extraradical AM fungal hyphae in the pasture soil under water-stressed conditions.

  7. The Influential Role of Sociocultural Feedbacks on Community-Managed Irrigation System Behaviors During Times of Water Stress

    Science.gov (United States)

    Gunda, T.; Turner, B. L.; Tidwell, V. C.

    2018-04-01

    Sociohydrological studies use interdisciplinary approaches to explore the complex interactions between physical and social water systems and increase our understanding of emergent and paradoxical system behaviors. The dynamics of community values and social cohesion, however, have received little attention in modeling studies due to quantification challenges. Social structures associated with community-managed irrigation systems around the world, in particular, reflect these communities' experiences with a multitude of natural and social shocks. Using the Valdez acequia (a communally-managed irrigation community in northern New Mexico) as a simulation case study, we evaluate the impact of that community's social structure in governing its responses to water availability stresses posed by climate change. Specifically, a system dynamics model (developed using insights from community stakeholders and multiple disciplines that captures biophysical, socioeconomic, and sociocultural dynamics of acequia systems) was used to generate counterfactual trajectories to explore how the community would behave with streamflow conditions expected under climate change. We found that earlier peak flows, combined with adaptive measures of shifting crop selection, allowed for greater production of higher value crops and fewer people leaving the acequia. The economic benefits were lost, however, if downstream water pressures increased. Even with significant reductions in agricultural profitability, feedbacks associated with community cohesion buffered the community's population and land parcel sizes from more detrimental impacts, indicating the community's resilience under natural and social stresses. Continued exploration of social structures is warranted to better understand these systems' responses to stress and identify possible leverage points for strengthening community resilience.

  8. On the water quality of selected environments along Bombay coast

    Digital Repository Service at National Institute of Oceanography (India)

    Krishnakumari, L.; Nair, V.R.

    Water quality of three stations representing polluted (Sts. B & S) and relatively unpolluted (St. M) areas along the coast of Bombay was studied during March 1981 to May 1982. Stations B & S were characterised by relatively wider fluctuations...

  9. Bacteriological investigation of ground water sources in selected ...

    African Journals Online (AJOL)

    cml

    2012-06-16

    Jun 16, 2012 ... Microbial contamination of ground water sources is a common problem in all the big cities, which endangers ... include leakage of pipes, pollution from sewerage pipes ..... and Quality Control Authority, Karachi, Pakistan.

  10. performance of water filters towards the removal of selected

    African Journals Online (AJOL)

    Morohani Merinyo

    sand, ceramic and membrane purifier respectively, while, fluoride removal was found to be 95.5% ... associated diseases in developing countries ... The main drinking water risks in developing ... Tanzania Demographic and Health Survey.

  11. Physiological response of selected eragrostis species to water ...

    African Journals Online (AJOL)

    Administrator

    2011-09-07

    Sep 7, 2011 ... Department of Molecular and Cell Biology, University of Cape Town, Private Bag, .... respiration measurements were taken at night (20:00 h). .... Cellular ultrastructure .... these in place, to be held at intermediate water contents.

  12. Potability Assessment of Selected Brands of Bottled Water in ...

    African Journals Online (AJOL)

    Michael Horsfall

    Department of Water Resources Management and Agrometeorology,. University of ... of high quality that could be consumed without risk of .... samples D, E & F values fall below the standard and .... Bertram and Balance (1996), when sulphate.

  13. Physical and chemical characteristics of water in selected locations

    African Journals Online (AJOL)

    need for comprehensive data and information on water quality. ... Dunn's Multiple Comparison Tests (Zar. 1984). RESULTS ..... Furthermore, lower secchi depth observed at ... Rainfall during this period .... main lake and satellite lakes of Lake.

  14. Potability Evaluation of Selected River Waters in Ebonyi State, Nigeria

    African Journals Online (AJOL)

    Akorede

    Water contains physiochemical materials and microbial organisms which are ... wide variety of organic and inorganic solid wastes and salts. A river is a ... in the determination of all the metallic elements such as Lead .... Architects Building.

  15. Nitrogen accumulation in lucerne (Medicago sativa L.) under water deficit stress

    OpenAIRE

    Vasileva Viliana; Vasilev Emil

    2013-01-01

    In order to study nitrogen accumulation in aboveground and root dry mass in lucerne (Medicago sativa L.) under water deficit stress, a pot experiment was carried out at the Institute of Forage Crops, Pleven, Bulgaria. The plants were grown under optimum water supply (75-80% FC) and 10-days water deficit stress was simulated at the stage of budding by interrupting the irrigation until soil moisture was reduced to 37-40% FC. Mineral nitrogen fertilization (ammonium nitrate) at the doses of 40, ...

  16. Selection of black poplars for water use efficiency

    OpenAIRE

    Orlović Saša S.; Pajević Slobodanka P.; Krstić Borivoj Đ.

    2002-01-01

    Photosynthesis, transpiration, water use efficiency (WUE) and biomass production have been investigated in nine black poplar clones (section Aigeiros) in three field experiments. Eastern cottonwood clones (Populus deltoides) had the highest net photosynthesis and water use efficiency. European black poplar clones had the highest transpiration intensity. Correlation analysis showed that net photosynthesis was in a high positive correlation with biomass. Medium negative correlations existed bet...

  17. Including Effects of Water Stress on Dead Organic Matter Decay to a Forest Carbon Model

    Science.gov (United States)

    Kim, H.; Lee, J.; Han, S. H.; Kim, S.; Son, Y.

    2017-12-01

    Decay of dead organic matter is a key process of carbon (C) cycling in forest ecosystems. The change in decay rate depends on temperature sensitivity and moisture conditions. The Forest Biomass and Dead organic matter Carbon (FBDC) model includes a decay sub-model considering temperature sensitivity, yet does not consider moisture conditions as drivers of the decay rate change. This study aimed to improve the FBDC model by including a water stress function to the decay sub-model. Also, soil C sequestration under climate change with the FBDC model including the water stress function was simulated. The water stress functions were determined with data from decomposition study on Quercus variabilis forests and Pinus densiflora forests of Korea, and adjustment parameters of the functions were determined for both species. The water stress functions were based on the ratio of precipitation to potential evapotranspiration. Including the water stress function increased the explained variances of the decay rate by 19% for the Q. variabilis forests and 7% for the P. densiflora forests, respectively. The increase of the explained variances resulted from large difference in temperature range and precipitation range across the decomposition study plots. During the period of experiment, the mean annual temperature range was less than 3°C, while the annual precipitation ranged from 720mm to 1466mm. Application of the water stress functions to the FBDC model constrained increasing trend of temperature sensitivity under climate change, and thus increased the model-estimated soil C sequestration (Mg C ha-1) by 6.6 for the Q. variabilis forests and by 3.1 for the P. densiflora forests, respectively. The addition of water stress functions increased reliability of the decay rate estimation and could contribute to reducing the bias in estimating soil C sequestration under varying moisture condition. Acknowledgement: This study was supported by Korea Forest Service (2017044B10-1719-BB01)

  18. Seed size effects on the response of seedlings of Acacia asak (Forssk.) Willd to water stress

    International Nuclear Information System (INIS)

    El Atta, H.A.; Areef, I.M.; Ahmed, A.I.

    2016-01-01

    Dry tropical forests are characterized by unpredictable spells of drought and climate change. Saudi Arabia mostly falls within the arid zone and some few scattered areas fall in the semiarid zone mainly in the South Western region. Rainfall is sparse and with sporadic distribution. Drought is the most critical factor for restoration of the tree cover. Within a tree, seeds vary in size from large to small seeds. Although several researchers have studied the effect of within species variation in seed size on seedlings growth parameters, however there is a lack of knowledge regarding the effect of seed size on stress tolerance (Khurana and Singh 2000). We assumed that seedlings grown from different seed sizes from the same tree species may influence their response to water stress. Seeds of Acacia asak (Forssk.) Willd. were categorized into large, medium and small seeds on the basis of the seed weight. Seedlings from the three seed sizes were grown in potted soil and subjected to 5 levels of field water capacity (FC) (100, 75, 50, 25 and 15 percent) in the greenhouse. The Objective was to evaluate the response of seedling grown (from different seed sizes) to water stress and to understand the acclimation of seedlings to water stress. Water stress significantly reduced RWC, leaf area, and shoot length, fresh and dry weight. Significant correlations between growth parameters and water stress level were recorded. Seedlings from large seeds were heavier and comparatively less affected by drought compared to seedlings from smaller seeds. In all seedlings root length increased significantly and more biomass was allocated to roots than to shoots. However, at severe water stress (15 percent FC) no significant differences were reported between the three seedling categories. Therefore, raising of seedlings from large seeds is more appropriate for tree restoration programs under drought conditions. (author)

  19. Plant Water Stress Affects Interactions Between an Invasive and a Naturalized Aphid Species on Cereal Crops.

    Science.gov (United States)

    Foote, N E; Davis, T S; Crowder, D W; Bosque-Pérez, N A; Eigenbrode, S D

    2017-06-01

    In cereal cropping systems of the Pacific Northwestern United States (PNW), climate change is projected to increase the frequency of drought during summer months, which could increase water stress for crop plants. Yet, it remains uncertain how interactions between herbivore species are affected by drought stress. Here, interactions between two cereal aphids present in PNW cereal systems, Metopolophium festucae (Theobald) subsp. cerealium (a newly invasive species) and Rhopalosiphum padi L. (a naturalized species), were tested relative to wheat water stress. When aphids were confined in leaf cages on wheat, asymmetrical facilitation occurred; per capita fecundity of R. padi was increased by 46% when M. festucae cerealium was also present, compared to when only R. padi was present. Imposed water stress did not influence this interaction. When aphids were confined on whole wheat plants, asymmetrical competition occurred; cocolonization inhibited M. festucae cerealium population growth but did not affect R. padi population growth. Under conditions of plant water stress, however, the inhibitory effect of R. padi on M. festucae cerealium was not observed. We conclude that beneficial effects of cocolonization on R. padi are due to a localized plant response to M. festucae cerealium feeding, and that cocolonization of plants is likely to suppress M. festucae cerealium populations under ample water conditions, but not when plants are water stressed. This suggests that plant responses to water stress alter the outcome of competition between herbivore species, with implications for the structure of pest communities on wheat during periods of drought. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America.

  20. Combining ability studies on yield related traits in wheat under normal and water stress conditions

    International Nuclear Information System (INIS)

    Saeed, A.; Khan, A.S.; Khaliq, I.

    2010-01-01

    Six diverse wheat cultivars/lines viz; Baviacore, Nesser, 9247, 9252, 9258 and 9267 were crossed in a complete diallel fashion to develop 30 F1 crosses, which were tested along with their parents under normal and water stress conditions. Numerical analysis was made for spike density, number of grains per spike, 100-grain weight, biological yield, grain yield and harvest index. Significant differences among genotypic mean were observed in all of the traits under both conditions. GCA and SCA differences were significant for all the traits under study except spike density and 100-grain weight in both conditions. Wheat variety Nesser showed maximum general combining ability value for spike density under water stress conditions and maximum GCA value for biological yield and grain yield under irrigated condition. The variety Baviacore proved best general combiner for number of grains per spike and harvest index under both conditions while biological yield and grain yield under water stress condition. Variety 9252 found best general combiner for 100-grain weight under both condition. The cross 9252 x Nesser showed maximum specific combining ability value for spike density and biological yield under irrigated while for 100-grain weight under water stress condition. 9258 x 9252 exhibited maximum SCA for number of grains per spike under irrigated while 9258 x Nesser under water stress condition. 9267 x Nesser showed maximum SCA for 100-grain weight under irrigated condition while spike density under water stress condition. 9258 x 9247 was proved best combiner for grain yield and harvest index irrigated while 9267 x 9258 for biological yield, grain yield and harvest index under water stress condition. (author)

  1. Detecting long-term low-irradiance stress and water stress of trees with laser-induced fluorescence measurements

    International Nuclear Information System (INIS)

    Sagawa, M.; Kurata, K.; Takahashi, K.; Mineuchi, K.

    2001-01-01

    The objective of this study was to find simple and objective methods of diagnosing the ailments of trees in indoor spaces, such as atriums. In this study, two simple diagnostics were compared. One was the analysis of the laser-induced fluorescence spectra of leaves and the other was the analysis of the laser-induced chlorophyll-fluorescence induction kinetics (Kautsky effect). In the latter analysis, second time derivatives of the induction-kinetics curves were used. Cinnamomum camphora and Quercus myrsinifolia grown under different light conditions and Cinnamomum camphora under water stress were used in the experiments. The effects of low irradiance were detected in both the induction kinetics and the spectra; however, the effects of water stress were detected in the induction kinetics only. These results indicate the possibility of utilizing laser-induced-fluorescence induction-kinetics for diagnosing the ailments of trees. (author)

  2. Effects of water stress and light intensity on chlorophyll fluorescence parameters and pigments of Aloe vera L.

    Science.gov (United States)

    Hazrati, Saeid; Tahmasebi-Sarvestani, Zeinolabedin; Modarres-Sanavy, Seyed Ali Mohammad; Mokhtassi-Bidgoli, Ali; Nicola, Silvana

    2016-09-01

    Aloe vera L. is one of the most important medicinal plants in the world. In order to determine the effects of light intensity and water deficit stress on chlorophyll (Chl) fluorescence and pigments of A. vera, a split-plot in time experiment was laid out in a randomized complete block design with four replications in a research greenhouse. The factorial combination of three light intensities (50, 75 and 100% of sunlight) and four irrigation regimes (irrigation after depleting 20, 40, 60 and 80% of soil water content) were considered as main factors. Sampling time was considered as sub factor. The first, second and third samplings were performed 90, 180 and 270 days after imposing the treatments, respectively. The results demonstrated that the highest light intensity and the severe water stress decreased maximum fluorescence (Fm), variable fluorescence (Fv)/Fm, quantum yield of PSII photochemistry (ФPSII), Chl and photochemical quenching (qP) but increased non-photochemical quenching (NPQ), minimum fluorescence (F0) and Anthocyanin (Anth). Additionally, the highest Fm, Fv/Fm, ФPSII and qP and the lowest NPQ and F0 were observed when 50% of sunlight was blocked and irrigation was done after 40% soil water depletion. Irradiance of full sunlight and water deficit stress let to the photoinhibition of photosynthesis, as indicated by a reduced quantum yield of PSII, ФPSII, and qP, as well as higher NPQ. Thus, chlorophyll florescence measurements provide valuable physiological data. Close to half of total solar radiation and irrigation after depleting 40% of soil water content were selected as the most efficient treatments. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  3. Eucalypt plantation management in regions with water stress ...

    African Journals Online (AJOL)

    Southern Forests: a Journal of Forest Science ... using appropriate site management practices is a key challenge to sustain or increase productivity. ... of the current issues facing natural resources, and is likely to intensify the water constraint.

  4. Water Stress Assessment in Jharkhand State Using Soil Data and ...

    African Journals Online (AJOL)

    Michael Horsfall

    2 Department of Remote Sensing, Birla Institute of Technology, Mesra, Ranchi. .... technology. Remote sensing and GIS have proved to be an effective tool in soil and water resource assessment (Rinos et.al.; .... ral_hazard/landslides/nhls0007.

  5. Climate change and the vulnerability of electricity generation to water stress in the European Union

    Science.gov (United States)

    Behrens, Paul; van Vliet, Michelle T. H.; Nanninga, Tijmen; Walsh, Brid; Rodrigues, João F. D.

    2017-08-01

    Thermoelectric generation requires large amounts of water for cooling. Recent warm periods have led to curtailments in generation, highlighting concerns about security of supply. Here we assess EU-wide climate impacts for 1,326 individual thermoelectric plants and 818 water basins in 2020 and 2030. We show that, despite policy goals and a decrease in electricity-related water withdrawal, the number of regions experiencing some reduction in power availability due to water stress rises from 47 basins to 54 basins between 2014 and 2030, with further plants planned for construction in stressed basins. We examine the reasons for these pressures by including water demand for other uses. The majority of vulnerable basins lie in the Mediterranean region, with further basins in France, Germany and Poland. We investigate four adaptations, finding that increased future seawater cooling eases some pressures. This highlights the need for an integrated, basin-level approach in energy and water policy.

  6. Synthetic sea water - An improved stress corrosion test medium for aluminum alloys

    Science.gov (United States)

    Humphries, T. S.; Nelson, E. E.

    1973-01-01

    A major problem in evaluating the stress corrosion cracking resistance of aluminum alloys by alternate immersion in 3.5 percent salt (NaCl) water is excessive pitting corrosion. Several methods were examined to eliminate this problem and to find an improved accelerated test medium. These included the addition of chromate inhibitors, surface treatment of specimens, and immersion in synthetic sea water. The results indicate that alternate immersion in synthetic sea water is a very promising stress corrosion test medium. Neither chromate inhibitors nor surface treatment (anodize and alodine) of the aluminum specimens improved the performance of alternate immersion in 3.5 percent salt water sufficiently to be classified as an effective stress corrosion test method.

  7. Biomass production and water use efficiency in perennial grasses during and after drought stress

    DEFF Research Database (Denmark)

    Sørensen, Kirsten Kørup; Lærke, Poul Erik; Sørensen, Helle Baadsgaard

    2018-01-01

    be suitable for assessment of drought stress. There were indications of positive associations between plants carbon isotope composition and water use efficiency (WUE) as well as DM under well-watered conditions. Compared to control, drought-treated plots showed increased growth in the period after drought...... stress. Thus, the drought events did not affect total biomass production (DMtotal) of the whole growing season. During drought stress and the whole growing season, WUE was higher in drought-treated compared to control plots, so it seems possible to save water without loss of biomass. Across soil types, M......Drought is a great challenge to agricultural production, and cultivation of drought-tolerant or water use-efficient cultivars is important to ensure high biomass yields for bio-refining and bioenergy. Here, we evaluated drought tolerance of four C3 species, Dactylis glomerata cvs. Sevenop and Amba...

  8. Natural selection underlies apparent stress-induced mutagenesis in a bacteriophage infection model.

    Science.gov (United States)

    Yosef, Ido; Edgar, Rotem; Levy, Asaf; Amitai, Gil; Sorek, Rotem; Munitz, Ariel; Qimron, Udi

    2016-04-18

    The emergence of mutations following growth-limiting conditions underlies bacterial drug resistance, viral escape from the immune system and fundamental evolution-driven events. Intriguingly, whether mutations are induced by growth limitation conditions or are randomly generated during growth and then selected by growth limitation conditions remains an open question(1). Here, we show that bacteriophage T7 undergoes apparent stress-induced mutagenesis when selected for improved recognition of its host's receptor. In our unique experimental set-up, the growth limitation condition is physically and temporally separated from mutagenesis: growth limitation occurs while phage DNA is outside the host, and spontaneous mutations occur during phage DNA replication inside the host. We show that the selected beneficial mutations are not pre-existing and that the initial slow phage growth is enabled by the phage particle's low-efficiency DNA injection into the host. Thus, the phage particle allows phage populations to initially extend their host range without mutagenesis by virtue of residual recognition of the host receptor. Mutations appear during non-selective intracellular replication, and the frequency of mutant phages increases by natural selection acting on free phages, which are not capable of mutagenesis.

  9. Responses of KT2440 Pseudomonas putida to mild water stress

    DEFF Research Database (Denmark)

    Gülez, Gamze

    betydningen af flagellær motilitet og produktion af EPS under matric stess undersøgt ved brug af den såkaldte Porous Surface Model (PSM), som genererer væske-filmens effekter ved kontrol af !m. Det blev vist, at flagellær motilitet var begrænset under matric stress; Pseudomonas putida KT2440 kolonier udviste...... væsentlig højere vækstrater tæt ved mætningsbetingelser (-0.5 kPa !m) end kolonier dyrket under matric stress (ved -3.6 kPa !m). Desuden viste 1:1 kompettitive eksperimenter med begge phenotyper ved mættede betingelser, at den naturligt forekomne KT2440 udkonkurrerer dens ikke-flagellare mutant med hensyn...... til overflade-kolonivækst, hvorimod begge phenotyper sameksisterer under matric stress (-3.6 kPa). Denne afhandling har endvidere vist at bakterierne kunne drage fordel af pludseligt forekomne mættede betingelser (5 minutter, to gange dagligt) idet flagellær motilitet blev observeret. Dette resultat...

  10. Marinesco-Sjögren syndrome protein SIL1 regulates motor neuron subtype-selective ER stress in ALS

    NARCIS (Netherlands)

    Filézac de L'Etang, Audrey; Maharjan, Niran; Cordeiro Braña, Marisa; Ruegsegger, Céline; Rehmann, Ruth; Goswami, Anand; Roos, Andreas; Troost, Dirk; Schneider, Bernard L.; Weis, Joachim; Saxena, Smita

    2015-01-01

    Mechanisms underlying motor neuron subtype-selective endoplasmic reticulum (ER) stress and associated axonal pathology in amyotrophic lateral sclerosis (ALS) remain unclear. Here we show that the molecular environment of the ER between motor neuron subtypes is distinct, with characteristic

  11. Water and Salt Stresses, Kinetin and Protein Synthesis in Tobacco Leaves 1

    Science.gov (United States)

    Ben-Zioni, Aliza; Itai, C.; Vaadia, Y.

    1967-01-01

    The capacity of tobacco (Nicotiana rustica) leaf discs to incorporate l-leucine 14C into proteins was measured. Leaf discs were obtained from plants which experienced soil water depletion, or which were exposed to a saline or osmotic stress in the root medium. The stresses were brief of relatively short duration and water potential did not decrease below 4 bars in the root media. Leaf discs were sampled 2 hours after stress removal, achieved by reirrigation, or replacement of saline and osmotic solutions with normal nutrient solution. Plants were always turgid when leaves were sampled. All stressed tissues showed reduced capacity to incorporate l-leucine 14C into protein. The reduction was about 50% and could not be attributed either to reduced uptake into the discs, or to possible isotopic dilution. Incorporation decreased progressively with leaf age in control discs as well as in stressed leaf discs. At all ages tested, incorporation in stressed discs was lower than that of the control. Full recovery of incorporation capacity in stressed discs was obtained when discs were sampled 72 hours after stress removal but not earlier. Kinetin pretreatment prior to incubation with labelled leucine partially restored incorporation in stressed discs. The differences in response to kinetin of stressed and control discs suggest a lower endogenous level of cytokinins in the stressed discs. The results were qualitatively similar regardless of the kind of stress given to the plants during pretreatment. This supports the hypothesis that the normal supply of root cytokinins is important in shoot metabolism. PMID:16656515

  12. Dual-Level Material and Psychological Assessment of Urban Water Security in a Water-Stressed Coastal City

    Directory of Open Access Journals (Sweden)

    Yajing Huang

    2015-04-01

    Full Text Available The acceleration of urbanization and industrialization has been gradually aggravating water security issues, such as water shortages, water pollution, and flooding or drought disasters and so on. Water security issues have become a great challenge to urban sustainable development. In this context, we proposed a dual-level material and psychological assessment method to assess urban water security. Psychological security coefficients were introduced in this method to combine material security and residents’ security feelings. A typical water-stressed coastal city in China (Dalian was chosen as a case study. The water security status of Dalian from 2010 to 2012 was analysed dynamically. The results indicated that the Dalian water security statuses from 2010 to 2012 were basically secure, but solutions to improve water security status and solve water resource problems are still required. This dual-level material and psychological assessment for urban water security has improved conventional material assessment through the introduction of psychological security coefficients, which can benefit decision-making for urban water planning, management and protection.

  13. Response of nutrients, minerals, antioxidant leaf pigments, vitamins, polyphenol, flavonoid and antioxidant activity in selected vegetable amaranth under four soil water content.

    Science.gov (United States)

    Sarker, Umakanta; Oba, Shinya

    2018-06-30

    Four selected vegetable amaranths were grown under four soil water content to evaluate their response in nutrients, minerals, antioxidant leaf pigments, vitamins, polyphenol, flavonoid and total antioxidant activity (TAC). Vegetable amaranth was significantly affected by variety, soil water content and variety × soil water content interactions for all the traits studied. Increase in water stress, resulted in significant changes in proximate compositions, minerals (macro and micro), leaf pigments, vitamin, total polyphenol content (TPC), and total flavonoid content (TFC) of vegetable amaranth. Accessions VA14 and VA16 performed better for all the traits studied. Correlation study revealed a strong antioxidant scavenging activity of leaf pigments, ascorbic acid, TPC and TFC. Vegetable amaranth can tolerate soil water stress without compromising the high quality of the final product in terms of nutrients and antioxidant profiles. Therefore, it could be a promising alternative crop in semi-arid and dry areas and also during dry seasons. Copyright © 2018. Published by Elsevier Ltd.

  14. Impact of water stress on growth reserves and re-growth of Themeda ...

    African Journals Online (AJOL)

    Four water stress treatments (T1 = 0–25%, T2 = 25–50%, T3 = 50–75% and T4 = 75–100% depletion of plant available water) were applied to the plants in pots in a glasshouse. The TNCC declined drastically after severe defoliation over all the water treatments (P < 0.05), in all the plant parts (P < 0.05) and for all the growth ...

  15. Response of antioxidant system to drought stress and re-watering in Alfalfa during branching

    Science.gov (United States)

    Tina, R. R.; Shan, X. R.; Wang, Y.; Guo, S. Y.; Mao, B.; Wang, W.; Wu, H. Y.; Zhao, T. H.

    2017-11-01

    This paper aimed to reveal the response mechanism of active oxygen metabolism and antioxidant enzyme activities in Alfalfa under drought stress and re-watering, and the pot experiment was used, to explore the changes of H2O2, O2·-, electrolyte leakage conductivity and MDA, SOD, POD, CAT activity in Golden Empress (tolerant cultivar) and Sanditi (non-tolerant cultivar) under drought stress and re-watering during branching stage. Three water gradients were set up: CK (Maximum field capacity of 75%±5%), T1 (Maximum field capacity of 45%±5%), T2 (Maximum field capacity of 35%±5%) to compare, and the drought rehydration was also studied. Results: the results indicated that H2O2 content, O2·-production rate, relative conductivity and MDA content were higher than the control, and the increase extent of Golden Empress was higher than the Sanditi under drought stress and after re-watering the recovery capability of Golden Empress was also higher than the Sanditi. After 7 days of re-watering, all indexes were restored to the control level, indicating that the re-watering have compensation effect after drought. After drought stress, to weaken the damage of active oxygen Golden Empress was mainly by increasing the activity of POD and SOD, but Sanditi was mainly through the POD and CAT activity increased to effectively remove ROS. Under drought stress, active oxygen in leaves of Alfalfa increased, and thus the membrane system was damaged which lead to the increase of MDA content and relative electric conductivity. Plants play a defensive role by increasing the activity of antioxidant enzymes and scavenging reactive oxygen species. After re-watering, the stress effect was reduced, and the physiological indexes of plants were restored to the control level. In general, tolerant cultivar has stronger antioxidant properties under drought and re-watering.

  16. Effects of water stress on the root and shoot behaviour of rain-fed rice

    International Nuclear Information System (INIS)

    Bois, J.F.; Couchat, P.

    1983-01-01

    Application of the neutron technique to the roots of rain-fed rice seedlings during water stress has shown that there is a noticeable decrease in root diameter because of water loss and a slowing down of growth. At the leaf level the water deficiency results in modified gas exchanges due to closure of the stomata. Transpiration and photosynthesis appear to be independent of the soil-water potential above a threshold value in the neighbourhood of -600 mbar. Below this critical potential the closure of the stomata is progressive and proportional to the drop in water potential. (author)

  17. Sources of trends in water-quality data for selected streams in Texas, 1975-89 water years

    Science.gov (United States)

    Schertz, T.L.; Wells, F.C.; Ohe, D.J.

    1994-01-01

    Sources of trends in water-quality data for selected streams in Texas for the 1975-89 water years were investigated in this study. The investigation of sources was confined to distinct geographic patterns in the trend indicators for one constituent or for a group of related constituents.

  18. Interactive effects of rice residue and water stress on growth and metabolism of wheat seedlings

    Directory of Open Access Journals (Sweden)

    Nimisha Amist

    2014-08-01

    Full Text Available In the present study effects of rice residue with and without water stress were studied on Triticum aestivum L. cv. Shatabadi. The mixture of residue and garden soil in 1:1 ratio was considered as 50% (R1 and only decomposed residue as 100% (R2. Garden soil was taken as control. Twenty five seeds were sown in each experimental trays filled with soil mixture according to the treatments. Trays were arranged in two groups. After 15 days one set was subjected to water stress (WS by withholding water supply for 3 days. Morphological and biochemical parameters of 18 days old seedlings were recorded. Seedling height decreased in all treatments. A gradual decrease in relative water content, pigment and protein contents of wheat seedlings were observed. Sugar and proline contents increased in treatments. An increase in malondialdehyde (MDA content and antioxidative enzyme activities was recorded. Elevation in catalase activity was observed in all treatments except in plants with water deficit. Ascorbate peroxidase (APX and guaiacol peroxidase (GPX activities increased when residue mixed with soil but decreased in seedlings under the combined influence of the residue and water stress. Higher amount of MDA and lower activities of APX and GPX reflected the oxidative damage in seedlings under combined treatments. Rice residue inhibited growth of wheat seedlings. Water stress intensified the effects of residue.

  19. Polybenzimidazole-based mixed membranes with exceptional high water vapor permeability and selectivity

    KAUST Repository

    Akhtar, Faheem Hassan

    2017-09-13

    Polybenzimidazole (PBI), a thermal and chemically stable polymer, is commonly used to fabricate membranes for applications like hydrogen recovery at temperatures of more than 300 °C, fuel cells working in a highly acidic environment, and nanofiltration in aggressive solvents. This report shows for the first time use of PBI dense membranes for water vapor/gas separation applications. They showed an excellent selectivity and high water vapor permeability. Incorporation of inorganic hydrophilic titanium-based nano-fillers into the PBI matrix further increased the water vapor permeability and water vapor/N2 selectivity. The most selective mixed matrix membrane with 0.5 wt% loading of TiO2 nanotubes yielded a water vapor permeability of 6.8×104 Barrer and a H2O/N2 selectivity of 3.9×106. The most permeable membrane with 1 wt% loading of carboxylated TiO2 nanoparticles had a 7.1×104 Barrer water vapor permeability and a H2O/N2 selectivity of 3.1×106. The performance of these membranes in terms of water vapor transport and selectivity is among the highest reported ones. The remarkable ability of PBI to efficiently permeate water versus other gases opens the possibility to fabricate membranes for dehumidification of streams in harsh environments. This includes the removal of water from high temperature reaction mixtures to shift the equilibrium towards products.

  20. Polybenzimidazole-based mixed membranes with exceptional high water vapor permeability and selectivity

    KAUST Repository

    Akhtar, Faheem Hassan; Kumar, Mahendra; Villalobos, Luis Francisco; Shevate, Rahul; Vovusha, Hakkim; Schwingenschlö gl, Udo; Peinemann, Klaus-Viktor

    2017-01-01

    Polybenzimidazole (PBI), a thermal and chemically stable polymer, is commonly used to fabricate membranes for applications like hydrogen recovery at temperatures of more than 300 °C, fuel cells working in a highly acidic environment, and nanofiltration in aggressive solvents. This report shows for the first time use of PBI dense membranes for water vapor/gas separation applications. They showed an excellent selectivity and high water vapor permeability. Incorporation of inorganic hydrophilic titanium-based nano-fillers into the PBI matrix further increased the water vapor permeability and water vapor/N2 selectivity. The most selective mixed matrix membrane with 0.5 wt% loading of TiO2 nanotubes yielded a water vapor permeability of 6.8×104 Barrer and a H2O/N2 selectivity of 3.9×106. The most permeable membrane with 1 wt% loading of carboxylated TiO2 nanoparticles had a 7.1×104 Barrer water vapor permeability and a H2O/N2 selectivity of 3.1×106. The performance of these membranes in terms of water vapor transport and selectivity is among the highest reported ones. The remarkable ability of PBI to efficiently permeate water versus other gases opens the possibility to fabricate membranes for dehumidification of streams in harsh environments. This includes the removal of water from high temperature reaction mixtures to shift the equilibrium towards products.

  1. The effect of water stress on some morphological, physiological, and biochemical characteristics and bud success on apple and quince rootstocks.

    Science.gov (United States)

    Bolat, Ibrahim; Dikilitas, Murat; Ercisli, Sezai; Ikinci, Ali; Tonkaz, Tahsin

    2014-01-01

    The effects of different water stress (control, medium, and severe) on some morphological, physiological, and biochemical characteristics and bud success of M9 apple and MA quince rootstocks were determined. The results showed that water stress significantly affected most morphological, physiological, and biochemical characteristics as well as budding success on the both rootstocks. The increasing water stress decreased the relative shoot length, diameter, and plant total fresh and dry weights. Leaf relative water content and chlorophyll index decreased while electrolyte leakage increased with the increase of water stress in both rootstocks. An increase in water stress also resulted in reduction in budding success in Vista Bella/M9 (79.33% and 46.67%) and Santa Maria/MA (70.33% and 15.33%) combinations. However, the water stress in Santa Maria/MA was more prominent. The increase in water stress resulted in higher peroxidase activities as well as phenol contents in both rootstocks. Although catalase activity, anthocyanin, and proline contents increased with the impact of stress, this was not statistically significant. The results suggest that the impact of stress increased with the increase of water stress; therefore, growers should be careful when using M9 and MA rootstocks in both nursery and orchards where water scarcity is present.

  2. The Effect of Water Stress on Some Morphological, Physiological, and Biochemical Characteristics and Bud Success on Apple and Quince Rootstocks

    Directory of Open Access Journals (Sweden)

    Ibrahim Bolat

    2014-01-01

    Full Text Available The effects of different water stress (control, medium, and severe on some morphological, physiological, and biochemical characteristics and bud success of M9 apple and MA quince rootstocks were determined. The results showed that water stress significantly affected most morphological, physiological, and biochemical characteristics as well as budding success on the both rootstocks. The increasing water stress decreased the relative shoot length, diameter, and plant total fresh and dry weights. Leaf relative water content and chlorophyll index decreased while electrolyte leakage increased with the increase of water stress in both rootstocks. An increase in water stress also resulted in reduction in budding success in Vista Bella/M9 (79.33% and 46.67% and Santa Maria/MA (70.33% and 15.33% combinations. However, the water stress in Santa Maria/MA was more prominent. The increase in water stress resulted in higher peroxidase activities as well as phenol contents in both rootstocks. Although catalase activity, anthocyanin, and proline contents increased with the impact of stress, this was not statistically significant. The results suggest that the impact of stress increased with the increase of water stress; therefore, growers should be careful when using M9 and MA rootstocks in both nursery and orchards where water scarcity is present.

  3. Selected trace elements in Stockton, New Zealand, waters

    International Nuclear Information System (INIS)

    Alarcon Leon, E.; Anstiss, R.G.

    2002-01-01

    Ni, Mn, As, Pb, Cd, Cr, Cu, Hg, Se, Al, Zn, Fe, SO 4 2- , hardness (calc.) in addition to pH, total dissolved solids (TDS), and total suspended solids (TSS) were measured at 18 (11 surface and 7 subsurface) sampling sites (which were each assigned a semi-quantitative Mudstone Index (MI)) from 20 days over 9 months in the waters which drain the Stockton coal mine area on the Stockton Plateau, New Zealand. Trace element, TDS and TSS concentrations were found to be elevated and pH depressed consistent with acid mine drainage (AMD) and were characterised by significant variability due to environmental processes. Frequent concentration spikes in surface and subsurface waters occurred which sometimes exceeded maximum acceptable values (MAV) and/or aesthetic guideline values (GV) including a number of toxic trace elements. Mean concentrations of Ni and Mn in both surface and subsurface waters and As and Cd in subsurface waters exceeded MAVs. Mean concentrations of Mn, Al, Fe, SO 4 2- , and pH in both surface and subsurface waters exceeded GVs. There tends to be higher trace element and TDS concentrations where there are more mudstones (higher MI) with lower pHs. It is recommended that any further studies focus on geographic distribution, concentration fluctuation factors, movement, and possible exposure issues. (author). 7 refs., 1 fig., 3 tabs

  4. Water and salinity stress in grapevines: early and late changes in transcript and metabolite profiles.

    Science.gov (United States)

    Cramer, Grant R; Ergül, Ali; Grimplet, Jerome; Tillett, Richard L; Tattersall, Elizabeth A R; Bohlman, Marlene C; Vincent, Delphine; Sonderegger, Justin; Evans, Jason; Osborne, Craig; Quilici, David; Schlauch, Karen A; Schooley, David A; Cushman, John C

    2007-04-01

    Grapes are grown in semiarid environments, where drought and salinity are common problems. Microarray transcript profiling, quantitative reverse transcription-PCR, and metabolite profiling were used to define genes and metabolic pathways in Vitis vinifera cv. Cabernet Sauvignon with shared and divergent responses to a gradually applied and long-term (16 days) water-deficit stress and equivalent salinity stress. In this first-of-a-kind study, distinct differences between water deficit and salinity were revealed. Water deficit caused more rapid and greater inhibition of shoot growth than did salinity at equivalent stem water potentials. One of the earliest responses to water deficit was an increase in the transcript abundance of RuBisCo activase (day 4), but this increase occurred much later in salt-stressed plants (day 12). As water deficit progressed, a greater number of affected transcripts were involved in metabolism, transport, and the biogenesis of cellular components than did salinity. Salinity affected a higher percentage of transcripts involved in transcription, protein synthesis, and protein fate than did water deficit. Metabolite profiling revealed that there were higher concentrations of glucose, malate, and proline in water-deficit-treated plants as compared to salinized plants. The metabolite differences were linked to differences in transcript abundance of many genes involved in energy metabolism and nitrogen assimilation, particularly photosynthesis, gluconeogenesis, and photorespiration. Water-deficit-treated plants appear to have a higher demand than salinized plants to adjust osmotically, detoxify free radicals (reactive oxygen species), and cope with photoinhibition.

  5. Stress assisted selective ablation of ITO thin film by picosecond laser

    Science.gov (United States)

    Farid, Nazar; Chan, Helios; Milne, David; Brunton, Adam; M. O'Connor, Gerard

    2018-01-01

    Fast selective pattering with high precession on 175 nm ITO thin film with IR ps lasers is investigated. Ablation parameters are optimized with detailed studies on the scribed depth, topography, and particle generation using AFM and SEM. A comparison of 10 and 150 ps laser revealed that the shorter pulse (10 ps) laser is more appropriate in selective and partial ablation; up to 20 nm resolution for controlled depth with multipulses having energy below the damage threshold is demonstrated. The experimental results are interpreted to involve stress assisted ablation mechanism for the 10 ps laser while thermal ablation along with intense melting occurs for 150 ps laser. The transition between these regimes is estimated to occur at approximately 30 ps.

  6. Stress, Time Pressure, Strategy Selection and Math Anxiety in Mathematics: A Review of the Literature

    Directory of Open Access Journals (Sweden)

    Sara Caviola

    2017-09-01

    Full Text Available We review how stress induction, time pressure manipulations and math anxiety can interfere with or modulate selection of problem-solving strategies (henceforth “strategy selection” in arithmetical tasks. Nineteen relevant articles were identified, which contain references to strategy selection and time limit (or time manipulations, with some also discussing emotional aspects in mathematical outcomes. Few of these take cognitive processes such as working memory or executive functions into consideration. We conclude that due to the sparsity of available literature our questions can only be partially answered and currently there is not much evidence of clear associations. We identify major gaps in knowledge and raise a series of open questions to guide further research.

  7. Stress

    Science.gov (United States)

    ... can be life-saving. But chronic stress can cause both physical and mental harm. There are at least three different types of stress: Routine stress related to the pressures of work, family, and other daily responsibilities Stress brought about ...

  8. Expression of NCED gene in colored cotton genotypes subjected to water stress

    Directory of Open Access Journals (Sweden)

    Alexandre M. S. de Souza

    Full Text Available ABSTRACT Considering that the NCED gene acts on the biosynthetic cascade of ABA, a hormone involved in the functioning of stomata and consequently in the regulation of transpiration, the aim of this research was to analyze the expression of this gene in colored cotton genotypes subjected to water stress at the beginning of plant growth. Four colored cotton genotypes were used, subjected to two managements, with and without water stress, beginning the treatments when the blade of the first true leaves reached an area that allowed the evaluation of gas exchange. For the studies of the expression of the NCED gene, via RT-qPCR, leaves were collected on three distinct dates: at 4 and 6 days of water stress, and after the plants regained their turgor. The differential expression of NCED was found in all genotypes, with higher levels of expression related to six days of water stress. When the stomatal conductance was around 25%, there was overexpression in the genotype CNPA 2009.13, followed by CNPA 2009.6, BRS SAFIRA and CNPA 2009.11, confirming the data obtained in the semi-quantitative RT-PCR. The NCED gene is involved in the response to water stress in the vegetative phase of colored cotton.

  9. Mitigation of stress corrosion cracking in boiling water reactors

    International Nuclear Information System (INIS)

    Hanneman, R.E.; Cowan, R.L. II

    1980-01-01

    Intergranular stress corrosion cracking (IGSCC) has occurred in a statistically small number of weld heat affected zones (HAZ) of 304 SS piping in BWR's. A range of mitigating actions have been developed and qualified that provide viable engineering solutions to the unique aspects of (1) operating plants, (2) plants under various stages of construction, and (3) future plants. This paper describes the technical development of each mitigating concept, relates it to the fundamental causal factors for IGSCC, and discusses its applicability to operating, in-construction and new BWR's. 31 refs

  10. Effect of different periods of chronic heat stress with or without vitamin C supplementation on bone and selected serum parameters of broiler chickens.

    Science.gov (United States)

    Mosleh, Najmeh; Shomali, Tahoora; Nematollahi, Fahimeh; Ghahramani, Zahra; Ahrari Khafi, Mohammad Saeid; Namazi, Fatemeh

    2018-04-01

    This study evaluates the effect of different periods of chronic heat stress (CHS) on selected bone and serum parameters of broiler chickens with or without vitamin C administration. Ninety 23-day-old chickens were randomly allocated into seven groups: (1) control, (2) short-term CHS (5 days), (3) short-term CHS + vitamin C (12 g/100 l drinking water of a 50% product), (4) medium-term CHS (10 days), (5) medium-term CHS + vitamin C, (6) long-term CHS (20 days) and (7) long-term CHS + vitamin C. In heat-stressed groups the temperature was increased to 39 ± 1°C for 8 h/day. At the end of the experiment, blood samples were collected and shank, keel and tibia bones were removed. CHS was not associated with a drastic change in serum Ca and corticosterone, or bone characteristics (both cortical and trabecular bones in radiographical and histological evaluation), or birds' performance. Oxidative stress was present especially with short-term CHS. CHS, especially for short or medium periods, showed a tendency to increase serum vitamin C and administration of this vitamin did not make a significant change in its serum levels although it ameliorated oxidative stress. In conclusion, it seems that CHS is not associated with an appreciable change in broiler performance, bone characteristics, or selected serum parameters; and simultaneous vitamin C administration at the dosage of 12 g/100 l in drinking water has no beneficial effect apart from reducing oxidative stress especially in short-term chronically heat-stressed birds.

  11. Selected spices and their combination modulate hypercholesterolemia-induced oxidative stress in experimental rats

    Directory of Open Access Journals (Sweden)

    Gloria A Otunola

    2014-01-01

    Full Text Available BACKGROUND: Effect of aqueous extracts of Allium sativum (garlic, Zingiber officinale (ginger, Capsicum fructensces (cayenne pepper and their mixture on oxidative stress in rats fed high Cholesterol/high fat diet was investigated. Rats were randomly distributed into six groups (n = 6 and given different dietary/spice treatments. Group 1 standard rat chow (control, group 2, hypercholesterolemic diet plus water, and groups 3, 4, 5, 6, hypercholesterolemic diet with 0.5 ml 200 mg · kg-1 aqueous extracts of garlic, ginger, cayenne pepper or their mixture respectively daily for 4 weeks. RESULTS: Pronounced oxidative stress in the hypercholesterolemic rats evidenced by significant (p < 0.05 increase in MDA levels, and suppression of the antioxidant enzymes system in rat's liver, kidney, heart and brain tissues was observed. Extracts of spices singly or combined administered at 200 mg.kg-1 body weight significantly (p < 0.05 reduced MDA levels and restored activities of antioxidant enzymes. CONCLUSIONS: It is concluded that consumption of garlic, ginger, pepper, or their mixture may help to modulate oxidative stress caused by hypercholesterolemia in rats.

  12. A water soluble heteropolyoxotungstate as a selective, efficient and ...

    Indian Academy of Sciences (India)

    Administrator

    In the catalytic system described here product isolation is easy, and the aqueous catalyst solution can be re-used several times with little loss in ... tle loss in the total amount of the heavy metal, which makes the overall process green ..... Chem. Res. 27 387. 12. Waters T, O'Hair R A J and Wedd A G 2003 J. Am. Chem. Soc.

  13. Effects of soil and water conservation practices on selected soil ...

    African Journals Online (AJOL)

    Although different types of soil and water conservation practices (SWCPs) were introduced, the sustainable use of these practices is far below expectations, and soil erosion continues to be a severe problem in Ethiopia. Therefore, this study was conducted at Debre Yakobe Micro-Watershed (DYMW), Northwest Ethiopia ...

  14. Temperature-Induced, Selective Assembly of Supramolecular Colloids in Water

    NARCIS (Netherlands)

    Van Ravensteijn, Bas G.P.; Vilanova, Neus; De Feijter, Isja; Kegel, Willem K.; Voets, Ilja K.

    2017-01-01

    In this article, we report the synthesis and physical characterization of colloidal polystyrene particles that carry water-soluble supramolecular N,N′,N″,-trialkyl-benzene-1,3,5-tricarboxamides (BTAs) on their surface. These molecules are known to assemble into one-dimensional supramolecular

  15. Selective Photooxidation Reactions using Water-Soluble Anthraquinone Photocatalysts

    NARCIS (Netherlands)

    Zhang, W.; Gacs, Jenő; Arends, I.W.C.E.; Hollmann, F.

    2017-01-01

    The aerobic organocatalytic oxidation of alcohols was achieved by using water-soluble sodium anthraquinone sulfonate. Under visible-light activation, this catalyst mediated the aerobic oxidation of alcohols to aldehydes and ketones. The photo-oxyfunctionalization of alkanes was also possible

  16. Ozone and Water Stress: Effects on the Behaviour of Two White Clover Biotypes

    Directory of Open Access Journals (Sweden)

    Massimo Fagnano

    Full Text Available ozone pollution, water stress, stomata conductance, ozone uptake, clover, OTC.Ozone is a strong oxidizing pollutant which derives by alteration of the photolytic NOx cycle and it accumulates in the troposphere spreading in rural areas and therefore determining injuries on natural vegetation and crops. Since its penetration occurs mainly through stomata, all factors which alter plant-atmosphere relations could be able to modify plant response to ozone. Interaction between ozone and water stress in Mediterranean environment was studied on ozone resistant and sensitive biotypes of white clover, which were grown in charcoal filtered and notfiltered Open Top Chambers in factorial combination with different levels of water supply. Measurements of biomass, leaf area and stomatal conductance were made during the growth period. Ozone injuries were estimated as not-filtered/filtered OTC yield ratio; the stomatal flux of ozone was estimated multiplying stomata conductance x diffusivity ratio between ozone and water vapour (0.613 x ozone hourly concentrations. The hourly values of ozone uptake were cumulated throughout the cropping periods of the two years. In the sensitive biotype, water stress reduced yield losses due to ozone from 38% to 22%, as well as yield losses due to water stress were reduced by the presence of ozone from 43% to 29%, while no interaction between ozone and water stress was observed in the resistant biotype. Biomass yield losses of the sensitive biotype were strictly correlated to cumulated ozone uptake (R2 = 0.99, while biomass yield losses of the resistant biotype were not affected by the ozone fluxes variations created by the treatments. Flux based models could better estimate yield losses due to ozone in Mediterranean environments in which other stresses could be contemporary present; therefore, the new European directives might replace the actual thresholds based

  17. Stress selection indices an acceptable tool to screen superior wheat genotypes under irrigated and rain-fed conditions

    International Nuclear Information System (INIS)

    Ullah, H.; Alam, M.

    2014-01-01

    The climate is changing day by day and water scarcity has developed a milieu for the breeder to think accordingly. Twenty-four advanced wheat lines along with four prominent check cultivars were evaluated independently in irrigated (IRE) and rain-fed environments (RFE) for yield related traits at Khyber Pakhtunkhwa, Pakistan during 2010-11, using randomized complete block design with three replications under each test environment. Analysis of variance across the two environments exhibited highly significant variation (p=0.01) among the genotypes for yield and associated traits. Differences among the two test environments (E) were significant for tillers m/sup -2/, 1000-grain weight and harvest index. Genotype * environment interaction (G*E) effects were significant only for 1000-grain weight and grain yield. There was general reduction in 1000-grain weight, biological yield and grain yield of all genotypes under RFE as compared to IRE. Magnitude of heritabilities estimates were greater for tillers m/sup -2/, spikelets spike-1 and grains spike-1 under IRE than RFE. Heritabilities were greater in RFE than IRE for spike length (0.31 vs 0.26), biological yield (0.80 vs 0.22), grain yield (0.94 vs 0.20) and harvest index (0.41 and 0.39). Relative high expected selection response was recorded for all characters under IRE except spike length, grains spike-1 and grain yield. In IRE, highest grain yield was produced by genotypes BRF-7 (5123 kg ha/sup -1/), B-VI(N)16 (5111 kg ha/sup -1/), B-IV(N)1 (5086 kg ha/sup -1/) and B-VI(N)5 (5049 kg ha/sup -1/), while genotypes B-VI(N)5 (4649 kg ha/sup -1/), B-IV(N)1 (4595 kg ha/sup -1/), BRF-7 (4486 kg ha/sup -1/) and B-IV(N)16 (4462 kg ha/sup -1/) were high yielding under RFE. Prominent stress selection indices used in the experiments were mean productivity (MP), tolerance (TOL), stress tolerance index (STI), trait index (TI) and trait stability index (TSI). MP and STI were the efficient and reliable selection indices in both

  18. Fluxes of 13 selected pharmaceuticals in the water cycle of Stockholm, Sweden.

    Science.gov (United States)

    Wahlberg, C; Björlenius, B; Paxéus, N

    2011-01-01

    Mass flows of 13 pharmaceutical active ingredients (APIS) found in drinking water were studied in the water cycle of Stockholm. Data were collected by analyzing samples of surface water, raw water and drinking water as well as influents, effluents and sludges from waste water treatment plants (WWTPs) in Stockholm area. A mass balance was performed, based on sold amounts of pharmaceuticals and the measured concentrations in water and sludge. The selected APls were all present in WWTP effluents and the removal rates for many of them were poor. Mass balance calculations showed that the three studied WWTPs in Stockholm release considerable amounts of the selected APIs into the Baltic Sea while the portions ending up in WWTP sludge were significantly lower. The levels of APIs found in drinking water are low at present, but may increase in the future unless the releases from WWTPs in the catchment of Lake Mälären are mitigated.

  19. Comparisons of Photosynthetic Responses of Xanthium strumarium and Helianthus annuus to Chronic and Acute Water Stress in Sun and Shade.

    Science.gov (United States)

    Ben, G Y; Osmond, C B; Sharkey, T D

    1987-06-01

    We have examined the effects of mild, chronic water stress and acute water stress on two water stress sensitive plants, Xanthium strumarium and Helianthus annuus. Using a combination of the leaf disc O(2) electrode to measure the light responses of photosynthesis and 77 K fluorescence to monitor damage to the primary photochemistry, we have found the following: (a) The CO(2) saturated rate of photosynthesis at high light is the most water stress sensitive parameter measured. (b) The apparent quantum yield (moles O(2) per mole photons) was slightly, if at all, affected by mild water stress (>-1.5 megapascals). (c) Severe water stress (<-1.5 megapascals) reduced the quantum yield of photosynthesis regardless of whether the stress was applied in sun or shade. The light independent reduction of quantum yield was not associated with a reduction in 77 K fluorescence (F(v)/F(m)) indicating that the quantum yield reduction was not the result of damage to primary photochemistry. (d) The diel fluctuation in 77 K fluorescence seen in sun-exposed control leaves was greatly exaggerated in water stressed leaves because of enhanced decline in 77 K fluorescence in the morning. The rate of recovery was similar in both control and water stressed leaves. Shaded leaves showed no change in 77 K fluorescence regardless of whether water stress was imposed or not. (e) The water stress sensitive plants used in these experiments did not recover from acute water stress severe enough to reduce the quantum yield or chronic water stress which lasted long enough that light dependent damage to primary photochemistry occurred.

  20. Water stress from high-volume hydraulic fracturing potentially threatens aquatic biodiversity and ecosystem services in Arkansas, United States

    Science.gov (United States)

    Entrekin, Sally; Trainor, Anne; Saiers, James; Patterson, Lauren; Maloney, Kelly O.; Fargione, Joseph; Kiesecker, Joseph M.; Baruch-Mordo, Sharon; Konschnik, Katherine E.; Wiseman, Hannah; Nicot, Jean-Philippe; Ryan, Joseph N.

    2018-01-01

    Demand for high-volume, short duration water withdrawals could create water stress to aquatic organisms in Fayetteville Shale streams sourced for hydraulic fracturing fluids. We estimated potential water stress using permitted water withdrawal volumes and actual water withdrawals compared to monthly median, low, and high streamflows. Risk for biological stress was considered at 20% of long-term median and 10% of high- and low-flow thresholds. Future well build-out projections estimated potential for continued stress. Most water was permitted from small, free-flowing streams and “frack” ponds (dammed streams). Permitted 12-h pumping volumes exceeded median streamflow at 50% of withdrawal sites in June, when flows were low. Daily water usage, from operator disclosures, compared to median streamflow showed possible water stress in 7–51% of catchments from June–November, respectively. If 100% of produced water was recycled, per-well water use declined by 25%, reducing threshold exceedance by 10%. Future water stress was predicted to occur in fewer catchments important for drinking water and species of conservation concern due to the decline in new well installations and increased use of recycled water. Accessible and precise withdrawal and streamflow data are critical moving forward to assess and mitigate water stress in streams that experience high-volume withdrawals.

  1. Water Stress from High-Volume Hydraulic Fracturing Potentially Threatens Aquatic Biodiversity and Ecosystem Services in Arkansas, United States.

    Science.gov (United States)

    Entrekin, Sally; Trainor, Anne; Saiers, James; Patterson, Lauren; Maloney, Kelly; Fargione, Joseph; Kiesecker, Joseph; Baruch-Mordo, Sharon; Konschnik, Katherine; Wiseman, Hannah; Nicot, Jean-Philippe; Ryan, Joseph N

    2018-02-20

    Demand for high-volume, short duration water withdrawals could create water stress to aquatic organisms in Fayetteville Shale streams sourced for hydraulic fracturing fluids. We estimated potential water stress using permitted water withdrawal volumes and actual water withdrawals compared to monthly median, low, and high streamflows. Risk for biological stress was considered at 20% of long-term median and 10% of high- and low-flow thresholds. Future well build-out projections estimated potential for continued stress. Most water was permitted from small, free-flowing streams and "frack" ponds (dammed streams). Permitted 12-h pumping volumes exceeded median streamflow at 50% of withdrawal sites in June, when flows were low. Daily water usage, from operator disclosures, compared to median streamflow showed possible water stress in 7-51% of catchments from June-November, respectively. If 100% of produced water was recycled, per-well water use declined by 25%, reducing threshold exceedance by 10%. Future water stress was predicted to occur in fewer catchments important for drinking water and species of conservation concern due to the decline in new well installations and increased use of recycled water. Accessible and precise withdrawal and streamflow data are critical moving forward to assess and mitigate water stress in streams that experience high-volume withdrawals.

  2. Morphological characteristics of BRS 501 sweet sorghum under water stress

    Directory of Open Access Journals (Sweden)

    Luciano Rezende Moreira

    2016-12-01

    Full Text Available Sorghum [Sorghum bicolor (L. Moench] crop is distinguished from other crops for its tolerance to both water deficit and excess soil moisture, under very dry and/or very hot environmental situations in which the productivity of other cereals becomes uneconomical. This work was conducted to evaluate the effects of irrigation on root conformation at the initial development phase of sweet sorghum. So, BRS 501 cv. was subjected to four irrigation levels based on 80%, 60%, 40% and 20% of the field capacity (CC. The decreased availability of water in the soil negatively affected the majority of the characteristics under evaluation except for the relationship between the root system and the aerial part (SR/PA, average root diameter (DMR and specific root area (ARE. We concluded that the growth of sweet sorghum plants under evaluation is sensible to the decrease of water in the soil, as it is affected by low water availability. This methodology, common to other crops, can be used for saccharine sorghum in order to establish hydric availabilities in new experiments to discriminate the drought-tolerant cultivars.

  3. Participation in a US community-based cardiovascular health study: investigating nonrandom selection effects related to employment, perceived stress, work-related stress, and family caregiving.

    Science.gov (United States)

    MacDonald, Leslie A; Fujishiro, Kaori; Howard, Virginia J; Landsbergis, Paul; Hein, Misty J

    2017-09-01

    Participation in health studies may be inversely associated with employment and stress. We investigated whether employment, perceived stress, work-related stress, and family caregiving were related to participation in a longitudinal US community-based health study of black and white men and women aged ≥45 years. Prevalence ratios and confidence intervals were estimated for completion of the second stage (S2) of a two-stage enrollment process by employment (status, type), and stress (perceived stress, work-related stress, caregiving), adjusting for age, sex, race, region, income, and education. Eligibility and consent for a follow-up occupational survey were similarly evaluated. Wage- but not self-employed participants were less likely than the unemployed to complete S2. Among the employed, S2 completion did not vary by stress; however, family caregivers with a short time burden of care (stress levels. Limited evidence of selection bias was seen by employment and stress within a large US community-based cohort, but findings suggest the need for enrollment procedures to consider possible barriers to participation among wage-employed individuals. Published by Elsevier Inc.

  4. Recent evolution of China's virtual water trade: analysis of selected crops and considerations for policy

    Science.gov (United States)

    Shi, J.; Liu, J.; Pinter, L.

    2014-04-01

    China has dramatically increased its virtual water import over recent years. Many studies have focused on the quantity of traded virtual water, but very few go into analysing geographic distribution and the properties of China's virtual water trade network. This paper provides a calculation and analysis of the crop-related virtual water trade network of China based on 27 major primary crops between 1986 and 2009. The results show that China is a net importer of virtual water from water-abundant areas of North America and South America, and a net virtual water exporter to water-stressed areas of Asia, Africa, and Europe. Virtual water import is far larger than virtual water export, and in both import and export a small number of trade partners control the supply chain. Grain crops are the major contributors to virtual water trade, and among grain crops, soybeans, mostly imported from the US, Brazil and Argentina, are the most significant. In order to mitigate water scarcity and secure the food supply, virtual water should actively be incorporated into national water management strategies. And the sources of virtual water import need to be further diversified to reduce supply chain risks and increase resilience.

  5. Breeding potential of the basmati rice germplasm under water stress ...

    African Journals Online (AJOL)

    Eight parents were selected on the basis of phenotypic and genotypic screening for the development of F1. All the possible combinations were made between the parents excluding reciprocals in diallel mating design. Data were analyzed by using Hayman graphical approach and Griffing's approach to study the genetics of ...

  6. The Stimulation Effects of N+ Ion Beam on Liquorice and Its Influence on Water Stress

    International Nuclear Information System (INIS)

    Wei Shenglin; Liu Jingnan; Wu Lijun; Wang Jiabao; Yu Zengliang

    2006-01-01

    We have developed a large number of exocrine glands on liquorice leaves and facilitated polysaccharide secretion. Liquorice polysaccharide possesses stronger bound water affinity to gaseous water compared with sucrose and glucose. Our results show that the bound water affinity of liquorice polysaccharide to gaseous water is 49.75% higher than glucose (p + implantation (total dosage of 4.68x10 16 ions/cm 2 and energy of 20 keV) into dry liquorice seeds, both the bound water affinity to gaseous water and the bound water content of dry liquorice leaf can be significantly increased 30.24% ( p + implantation into dry liquorice seeds, the leaf polysaccharide content under water stress (ψ w = -1.5 MPa) can increase significantly (p<0.05) and the plant growth can also improve significantly (p<0.05)

  7. Changes in seed water status as characterized by NMR in developing soybean seed grown under moisture stress conditions

    International Nuclear Information System (INIS)

    Krishnan, P.; Singh, Ravender; Verma, A.P.S.; Joshi, D.K.; Singh, Sheoraj

    2014-01-01

    Highlights: • In developing soybean seeds, moisture stress resulted in more proportion of water to bound state. • These changes are further corroborated by concomitant changes in seed metabolites. • Thus there exists a moisture stress and development stage dependence of seed tissue water status. - Abstract: Changes in water status of developing seeds of Soybean (Glycine max L. Merrill.) grown under different moisture stress conditions were characterized by proton nuclear magnetic resonance (NMR)- spin–spin relaxation time (T 2 ). A comparison of the seed development characteristics, composition and physical properties indicated that, characteristics like seed weight, seed number/ear, rate of seed filling increased with development stages but decreased with moisture stress conditions. The NMR- spin–spin relaxation (T 2 ) component like bound water increased with seed maturation (40–50%) but decreased with moisture stress conditions (30–40%). The changes in seed water status to increasing levels of moisture stress and seed maturity indicates that moisture stress resulted in more proportion of water to bound state and intermediate state and less proportion of water in free-state. These changes are further corroborated by significant changes in protein and starch contents in seeds under high moisture stress treatments. Thus seed water status during its development is not only affected by development processes but also by moisture stress conditions. This study strongly indicated a clear moisture stress and development stage dependence of seed tissue water status in developing soybean seeds

  8. Changes in seed water status as characterized by NMR in developing soybean seed grown under moisture stress conditions

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan, P., E-mail: pkrishnan@iari.res.in; Singh, Ravender; Verma, A.P.S.; Joshi, D.K.; Singh, Sheoraj

    2014-02-21

    Highlights: • In developing soybean seeds, moisture stress resulted in more proportion of water to bound state. • These changes are further corroborated by concomitant changes in seed metabolites. • Thus there exists a moisture stress and development stage dependence of seed tissue water status. - Abstract: Changes in water status of developing seeds of Soybean (Glycine max L. Merrill.) grown under different moisture stress conditions were characterized by proton nuclear magnetic resonance (NMR)- spin–spin relaxation time (T{sub 2}). A comparison of the seed development characteristics, composition and physical properties indicated that, characteristics like seed weight, seed number/ear, rate of seed filling increased with development stages but decreased with moisture stress conditions. The NMR- spin–spin relaxation (T{sub 2}) component like bound water increased with seed maturation (40–50%) but decreased with moisture stress conditions (30–40%). The changes in seed water status to increasing levels of moisture stress and seed maturity indicates that moisture stress resulted in more proportion of water to bound state and intermediate state and less proportion of water in free-state. These changes are further corroborated by significant changes in protein and starch contents in seeds under high moisture stress treatments. Thus seed water status during its development is not only affected by development processes but also by moisture stress conditions. This study strongly indicated a clear moisture stress and development stage dependence of seed tissue water status in developing soybean seeds.

  9. The transgenerational effects of heat stress in the nematode Caenorhabditis remanei are negative and rapidly eliminated under direct selection for increased stress resistance in larvae.

    Science.gov (United States)

    Sikkink, Kristin L; Ituarte, Catherine M; Reynolds, Rose M; Cresko, William A; Phillips, Patrick C

    2014-12-01

    Parents encountering stress environments can influence the phenotype of their offspring in a form of transgenerational phenotypic plasticity that has the potential to be adaptive if offspring are thereby better able to deal with future stressors. Here, we test for the existence of anticipatory parental effects in the heat stress response in the highly polymorphic nematode Caenorhabditis remanei. Rather providing an anticipatory response, parents subject to a prior heat stress actually produce offspring that are less able to survive a severe heat shock. Selection on heat shock resistance within the larvae via experimental evolution leads to a loss of sensitivity (robustness) to environmental variation during both the parental and larval periods. Whole genome transcriptional analysis of both ancestor and selected lines shows that there is weak correspondence between genetic pathways induced via temperature shifts during parental and larval periods. Parental effects can evolve very rapidly via selection acting directly on offspring. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Selection of inorganic-based fertilizers in forward osmosis for water desalination

    Directory of Open Access Journals (Sweden)

    Tripti Mishra

    2015-06-01

    Full Text Available The current study aims at the selection of an appropriate draw solute for forward osmosis process. Separation and recovery of the draw solute are the major criteria for the selection of draw solute for forward osmosis process. Therefore in this investigation six inorganic fertilizers draws solute were selected. The selections of inorganic fertilizers as draw solute eliminate the need of removal and recovery of draw solute from the final product. The final product water of forward osmosis process has direct application in agricultural as nutrient rich water for irrigation. These inorganic fertilizers were tested based on their water extraction (water flux capacity. This experimental water flux was compared with the observed water flux. It was noted that the observed water flux is much higher than the attained experimental water flux. The difference of these two fluxes was used to calculate the performance ratio of each selected fertilizer. Highest performance ratio was shown by low molecular weight compound ammonium nitrate (22.73 and potassium chloride (21.03 at 1 M concentration, whereas diammonium phosphate (DAP which has highest molecular weight among all the selected fertilizer show the lowest performance ratio (10.02 at 2 M concentration. DOI: http://dx.doi.org/10.3126/ije.v4i2.12660 International Journal of Environment Vol.4(2 2015: 319-329

  11. Response of antioxidant system of tomato to water deficit stress and its interaction with ascorbic acid

    Directory of Open Access Journals (Sweden)

    Fatemeh Daneshmand

    2014-03-01

    Full Text Available Environmental stresses including water deficit stress may produce oxidants such as reactive oxygen species that damage the membrane structure in plants. Among the antioxidants, ascorbic acid has a critical role in the cell and scavenges reactive oxygen species. In this research, effects of ascorbic acid at two levels (0 and 10 mM and water deficit stress based on 3 levels of field capacity (100, 60 and 30% were studied in tomato plants. Both levels of stress increased lipid peroxidation, reduced the amount of ascorbic acid and glutathione and increased the activity of enzymes superoxide dismutase, catalase, ascorbate peroxidase, glutathione reductase, guaiacol peroxidase and reduced the growth parameters. Ascorbic acid treatment, reduced lipid peroxidation, increased ascorbic acid and glutathione levels and decreased the activity of superoxide dismutase, catalase, ascorbate peroxidase, glutathione peroxidase and guaiacol peroxidase and positive effects of ascorbic acid treatment appeared to improve the plant growth parameters.

  12. Evaluation of stress-corrosion cracking of sensitized 304SS in low-temperature borated water

    International Nuclear Information System (INIS)

    Jones, R.H.; Johnson, A.B. Jr.; Bruemmer, S.M.

    1981-05-01

    Intergranular stress corrosion cracking has been observed in constant extension rate tests, CERT and constant load tests of 304SS tested at 32 0 C in borated water plus 15 ppM C1 - . Evidence of IGSCC was obtained in CERT tests of welded pipe samples only when the original inner diameter surface was intact and with 15 ppM C1 - added to the borated water while IGSCC occurred in a furnace sensitized pipe sample after 500 h at a constant stress of 340 MPa in borated water containing 15 ppM C1 - . These results indicate that surface features associated with weld preparation grinding contributed to the susceptibility of sensitized 304SS to IGSCC in low temperature borated water; however, the constant load test indicates that such surface defects are not necessary for IGSCC in low temperature borated water

  13. Seasonal water stress and the resistance of Pinus yunnanensis to a bark-beetle-associated fungus.

    Science.gov (United States)

    Salle, Aurelien; Ye, Hui; Yart, Annie; Lieutier, François

    2008-05-01

    We examined the influence of seasonal water stress on the resistance of Pinus yunnanensis (Franch.) to inoculation with Leptographium yunnanense, a pathogenic fungus associated with the aggressive bark beetle, Tomicus n. sp. Experiments took place between October 1997 and November 1999 in two plots located at the top and at the foot of a hill in Shaogiu, China, a region characterized by dry winters and wet summers. Following isolated and mass fungal inoculations, we observed the reaction zone length, fungal growth in the phloem, and the occlusion, blue-staining and specific hydraulic conductivity of the sapwood. Measurements of soil and needle water contents and predawn needle water potentials confirmed that trees were subject to mild water stress during winter, especially at the drier hilltop site. Measures of tree resistance to fungal infection of phloem and sapwood were congruent and indicated that trees were most susceptible to inoculation during the wet summer, especially at the lower-elevation plot. Specific hydraulic conductivity decreased after inoculation in summer. The results indicate that mild seasonal water stress is not likely responsible for the recent extensive damage to young P. yunnanensis stands by Tomicus n. sp. in the vicinity of our study plots. Rather, the results suggest that mild water stress enhances tree resistance to fungal pathogens associated with Tomicus n. sp.

  14. Effect of heat stress and genotype on water turnover in pregnant and lactating sheep

    International Nuclear Information System (INIS)

    Benlamlih, S.

    1988-01-01

    Studies on the effect of acute heat stress and on the influence of genotype on water turnover of pregnant and lactating ewes are described. Ewes exposed to acute heat stress during pregnancy and lactation maintained their body temperature within the same range as during the subsequent post-lactation period, but paradoxically the polypneic response was reduced during pregnancy. The drinking response to acute heat stress was markedly increased during pregnancy with a corresponding water diuresis. Thus, during acute heat stress, body temperature is maintained during pregnancy by the loss of heat to ingested water and probably also via increased sweating. Under natural environmental conditions, water turnover was higher in the sheep genotypes from the mountains (Timahdit) and the desert oases (Dman) than in the breeds from the Moroccan arid lands (Sardi and Beniguil). In all these genotypes, water turnover was lower during pregnancy than during lactation and the post-lactation period which occurred respectively in winter, spring and summer. Thus, the water demands during the summer are much higher than those for pregnancy during the winter months. (author). 7 refs, 3 figs, 1 tab

  15. Potential Foraging Decisions by a Desert Ungulate to Balance Water and Nutrient Intake in a Water-Stressed Environment.

    Science.gov (United States)

    Gedir, Jay V; Cain, James W; Krausman, Paul R; Allen, Jamison D; Duff, Glenn C; Morgart, John R

    2016-01-01

    water-stressed periods may not be necessary for desert bighorn sheep.

  16. Potential Foraging Decisions by a Desert Ungulate to Balance Water and Nutrient Intake in a Water-Stressed Environment.

    Directory of Open Access Journals (Sweden)

    Jay V Gedir

    water during water-stressed periods may not be necessary for desert bighorn sheep.

  17. Potential foraging decisions by a desert ungulate to balance water and nutrient intake in a water-stressed environment

    Science.gov (United States)

    Gedir, Jay V.; Cain, James W.; Krausman, Paul R.; Allen, Jamison D.; Duff, Glenn C.; Morgart, John R.

    2016-01-01

    water-stressed periods may not be necessary for desert bighorn sheep.

  18. Time Course Changes in Selected Biochemical Stress Indices in Broilers Exposed to Short-term Noise

    Directory of Open Access Journals (Sweden)

    Iveta Bedáňová

    2010-01-01

    Full Text Available Time course changes in selected biochemical stress indices (corticosterone, triglycerides, glucose, cholesterol following short-term noise exposure at 100 dB for 28 min were studied in broilers aged 42 days. Corticosterone concentrations were found to increase during the first 10 min of noise exposure and to differ significantly from the control (background sound – 50 dB at Time 10 min and 14 min, then decreased continually and at 28 min returned to the initial prestress value. Triglyceride concentrations increased in broilers exposed to 100 dB noise during the first 12 min with a significant difference from the control at 12 min and 14 min. Glucose concentrations were higher due to 100 dB noise exposure for almost the entire period monitored, with significant differences between 100 dB and control broilers at 6 min and from 10 min to 14 min. Similarly as for the corticosterone concentration, a drop in triglycerides and glucose concentrations was seen approximately from Time 14 min and a return to the pre-stress value at 28 min. The cholesterol concentrations showed various temporal patterns with no significant difference between 100 dB and control broilers in this experiment. The pattern of response found in the study indicates that 100 dB noise represents a stress factor in broilers, however, there is the ability of broilers to adapt to an increased level of noise at this intensity after the first 14 min of exposure. The findings obtained in the study may contribute to expanding detailed knowledge of physiological stress responses to this specific noise stimulus in poultry, and could thereby be used to improve the welfare of broilers in intensive housing systems.

  19. Speed of human tooth movement in growers and non-growers: Selection of applied stress matters.

    Science.gov (United States)

    Iwasaki, L R; Liu, Y; Liu, H; Nickel, J C

    2017-06-01

    To test that the speed of tooth translation is not affected by stress magnitude and growth status. Advanced Education Orthodontic clinics at the Universities of Nebraska Medical Center and Missouri-Kansas City. Forty-six consenting subjects with orthodontic treatment plans involving maxillary first premolar extractions. This randomized split-mouth study used segmental mechanics with definitive posterior anchorage and individual vertical-loop maxillary canine retraction appliances and measured three-dimensional tooth movements. Height and cephalometric superimposition changes determined growing (G) and non-growing (NG) subjects. Subjects were appointed for 9-11 visits over 84 days for maxillary dental impressions to measure three-dimensional tooth movement and to ensure retraction forces were continuously applied via calibrated nitinol coil springs. Springs were custom selected to apply two different stresses of 4, 13, 26, 52 or 78 kPa to maxillary canines in each subject. Statistical analyses (α=0.050) included ANOVA, effect size (partial η 2 ) and Tukey's Honest Significant Difference (HSD) and two-group t tests. Distolateral translation speeds were 0.034±0.015, 0.047±0.019, 0.066±0.025, 0.068±0.016 and 0.079±0.030 mm/d for 4, 13, 26, 52 and 78 kPa, respectively. Stress significantly affected speed and partial η 2 =0.376. Overall, more distopalatal rotation was shown by teeth moved by 78 kPa (18.03±9.50º) compared to other stresses (3.86±6.83º), and speeds were significantly higher (P=.001) in G (0.062±0.026 mm/d) than NG subjects (0.041±0.019 mm/d). Stress magnitude and growth status significantly affected the speed of tooth translation. Optimal applied stresses were 26-52 kPa, and overall speeds were 1.5-fold faster in G compared to NG subjects. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  20. Oxidization and stress corrosion cracking initiation of austenitic alloys in supercritical water

    International Nuclear Information System (INIS)

    Behnamian, Y.; Li, M.; Luo, J.L.; Chen, W.X.; Zheng, W.; Guzonas, D.A.

    2012-01-01

    This study determined the stress corrosion cracking behaviour of austenitic alloys in pure supercritical water. Austenitic stainless steels 310S, 316L, and Inconel 625 were tested as static capsule samples at 500 o C for up to 5000 h. After that period, crack initiations were readily observed in all samples, signifying susceptibility to stress corrosion cracking. The microcracks in 316L stainless steel and Inconel 625 were almost intergranular, whereas transgranular microcrack initiation was observed in 310S stainless steel. (author)

  1. Detoxication and recycling of radioactive waters using selective mineral sorbents

    International Nuclear Information System (INIS)

    Berak, L.

    1980-01-01

    Activated BaSO 4 (designated AB 70) was proposed for use in decontaminating concentrated calcium salt solutions containing a small amount of 226 Ra. The AB 70 concentration factor amounts to 2x1a 3 . A sorption contactor for applying the powder sorbent was proposed and will be tested. The AB 70 sorbent liberates small amounts of sulphates into the decontaminated solution, and thus another suitable mineral sorbent was sought. A new sorbent could be synthetized and tested, called RAS-1 whose Ra/Ca selectivity is comparable to that of AB 70 while its Ra/Ba selectivity is considerably higher. The RAS-1 sorbent is also suitable for radiochemical separation in the analysis and concentration of Ra. (Ha)

  2. Understanding Water-Stress Responses in Soybean Using Hydroponics System-A Systems Biology Perspective.

    Science.gov (United States)

    Tripathi, Prateek; Rabara, Roel C; Shulaev, Vladimir; Shen, Qingxi J; Rushton, Paul J

    2015-01-01

    The deleterious changes in environmental conditions such as water stress bring physiological and biochemical changes in plants, which results in crop loss. Thus, combating water stress is important for crop improvement to manage the needs of growing population. Utilization of hydroponics system in growing plants is questionable to some researchers, as it does not represent an actual field condition. However, trying to address a complex problem like water stress we have to utilize a simpler growing condition like the hydroponics system wherein every input given to the plants can be controlled. With the advent of high-throughput technologies, it is still challenging to address all levels of the genetic machinery whether a gene, protein, metabolite, and promoter. Thus, using a system of reduced complexity like hydroponics can certainly direct us toward the right candidates, if not completely help us to resolve the issue.

  3. Understanding Water-Stress Responses in Soybean Using Hydroponics System—A Systems Biology Perspective

    Science.gov (United States)

    Tripathi, Prateek; Rabara, Roel C.; Shulaev, Vladimir; Shen, Qingxi J.; Rushton, Paul J.

    2015-01-01

    The deleterious changes in environmental conditions such as water stress bring physiological and biochemical changes in plants, which results in crop loss. Thus, combating water stress is important for crop improvement to manage the needs of growing population. Utilization of hydroponics system in growing plants is questionable to some researchers, as it does not represent an actual field condition. However, trying to address a complex problem like water stress we have to utilize a simpler growing condition like the hydroponics system wherein every input given to the plants can be controlled. With the advent of high-throughput technologies, it is still challenging to address all levels of the genetic machinery whether a gene, protein, metabolite, and promoter. Thus, using a system of reduced complexity like hydroponics can certainly direct us toward the right candidates, if not completely help us to resolve the issue. PMID:26734044

  4. Survival, physical and physiological changes of Taenia hydatigena eggs under different conditions of water stress.

    Science.gov (United States)

    Sánchez Thevenet, Paula; Alvarez, Hector Manuel; Basualdo, Juan Angel

    2017-06-01

    Taenia hydatigena eggs were investigated for morphological and physiological changes under water stress conditions. Fresh eggs were exposed at 31%, 47% and 89% of relative humidity (RH), and survival, size and ultrastructural changes were accounted up to 365 days of exposition. The article shows how each RH environment affects the vitality of the eggs. Results of this study suggest that T. hydatigena eggs have mechanisms to withstand water stress, indicating that the eggs clustering improves protection against desiccation, and that endogenous metabolism using triacylglycerols play an important role in the maintenance of embryo vitality under low, medium and high relative humidity conditions. This contributes to understanding the water stress resistance mechanism in eggs belonging to Taeniidae family. The findings shown herein have provided a basis to better comprehend basic biology and epidemiology of the cysticercosis caused by T. hydatigena. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Assessment of water quality at selected Nigerian mining site ...

    African Journals Online (AJOL)

    From the results, Water bodies coded as WS had the highest pH, while NS had the least. Bicarbonate concentrations in mgL-1CaCO3 were found to be 2.50 for NS which are the highest, 1.94 for WS and 1.08 for as the least. Bicarbonate is the major contributor to alkalinity. The low level of hardness is evident of the fact that ...

  6. Selection criteria for the best secondary water chemistry

    International Nuclear Information System (INIS)

    Nordmann, F.; Fiquet, J.M.

    1996-01-01

    This paper describes, for PWR plants, the approach for selecting the best chemistry-pH, amine, corrosion inhibitors-according to the secondary system characteristics, such as presence or not of copper alloys, steam generator tubing alloy, tube support plate design, sludge pile importance. The impact of condensate polisher, sludge lancing, chemical cleaning, as well as other ways of eliminating undesirable compounds or mitigating them are also discussed. For plants with simultaneous presence of carbon steel and copper alloys, alternate amines like morpholine, or new reagents such as ethanolamine (ETA), can be selected to manage erosion-corrosion of carbon steel and decrease corrosion transport, at a pH acceptable for copper alloys (9.2 at 25 C). In more recent units, with an all ferrous system, a high pH operation, with only hydrazine addition, the easiest way, or with combined hydrazine and morpholine or ETA will be of some benefit against steam generator corrosion. When Alloy 600 has been selected, inhibitors such as boric acid, or maybe titanium oxide or cerium in the future, needs to be added in steam generators in order to decrease intergranular corrosion progression. In addition, caustic and lead contaminations must be strictly avoided, while sludge and deposits will be eliminated by lancing and chemical cleaning, if necessary. (orig.)

  7. Nitric oxide reduces oxidative damage induced by water stress in sunflower plants

    Directory of Open Access Journals (Sweden)

    Inês Cechin

    2015-06-01

    Full Text Available Drought is one of the main environmental constraints that can reduce plant yield. Nitric oxide (NO is a signal molecule involved in plant responses to several environmental stresses. The objective of this study was to investigate the cytoprotective effect of a single foliar application of 0, 1, 10 or 100 µM of the NO donor sodium nitroprusside (SNP in sunflower plants under water stress. Water stressed plants treated with 1μM SNP showed an increase in the relative water content compared with 0 μM SNP. Drought reduced the shoot dry weight but SNP applications did not result in alleviation of drought effects. Neither drought nor water stress plus SNP applications altered the content of photosynthetic pigments. Stomatal conductance was reduced by drought and this reduction was accompanied by a significant reduction in intercellular CO2 concentration and photosynthesis. Treatment with SNP did not reverse the effect of drought on the gas exchange characteristics. Drought increased the level of malondialdehyde (MDA and proline and reduced pirogalol peroxidase (PG-POD activity, but did not affect the activity of superoxide dismutase (SOD. When the water stressed plants were treated with 10 μM SNP, the activity of PG-POD and the content of proline were increased and the level of MDA was decreased. The results show that the adverse effects of water stress on sunflower plants are dependent on the external NO concentration. The action of NO may be explained by its ability to increase the levels of antioxidant compounds and the activity of ROS-scavenging enzymes.

  8. Study of sugar phloem unloading in ripening grape berries under water stress conditions

    Directory of Open Access Journals (Sweden)

    Zenphing Wang

    2003-12-01

    Full Text Available Sugar phloem unloading in ripening grape berries (Vitis vinifera L. cv. Syrah was studied under water stress conditions using the «beny-cup» technique. After veraison, berry growth, the potential Exposed Leaf Area (pELA and photosynthetic activity are clearly reduced in water-stressed vines (- 0.5 > Ψb > - 0.6 MPa as compared to normal 1 Ψ-watcred vines (Mb = - 0.2 MPa. The ratio pELA/yield is also reduced, which is particular to this experiment. The beiries' ripening period (between veraison and maturity can be divided into three growth phases, Illa, Illb and IIlc. During phase Ma, the berries grow rapidly; at this point, water stress severely inhibits cell expan¬ sion of the berries but does not impact on daily sugar accumulation. During phase Mb, the berries grow slowly in both water-stressed and control vines. Water stress can shorten this phase and reduce sugar accumulation in the berries by decreasing daily sugar unloading. During phase II le, the Iresh weight and volume of the berries decreases as does the daily sugar unloading. During the day, sugar unloading in ripening berries occurs mainly in the morning (7 am to 10.30 am and at noon (1 to 1.30 pm; little sugar is unloaded in the afternoon (4 pm to 4.30 pin. Moderate water stress from veraison to maturity affects végétative growth (i.e. the growth of primary and secoridary shoots, and reduces the exposed leaf area, photosynthetic activity, berry growth, and the accumulation of sugar at the end of ripening (phases Mb and IIlc.

  9. Variable Levels of Tolerance to Water Stress (Drought and Associated Biochemical Markers in Tunisian Barley Landraces

    Directory of Open Access Journals (Sweden)

    Sameh Dbira

    2018-03-01

    Full Text Available Due to its high tolerance to abiotic stress, barley (Hordeum vulgare is cultivated in many arid areas of the world. In the present study, we evaluate the tolerance to water stress (drought in nine accessions of “Ardhaoui” barley landraces from different regions of Tunisia. The genetic diversity of the accessions is evaluated with six SSR markers. Seedlings from the nine accessions are subjected to water stress by completely stopping irrigation for three weeks. A high genetic diversity is detected among the nine accessions, with no relationships between genetic distance and geographical or ecogeographical zone. The analysis of growth parameters and biochemical markers in the water stress-treated plants in comparison to their respective controls indicated great variability among the studied accessions. Accession 2, from El May Island, displayed high tolerance to drought. Increased amounts of proline in water-stressed plants could not be correlated with a better response to drought, as the most tolerant accessions contained lower levels of this osmolyte. A good correlation was established between the reduction of growth and degradation of chlorophylls and increased levels of malondialdehyde and total phenolics. These biochemical markers may be useful for identifying drought tolerant materials in barley.

  10. Selection of drought tolerant and high water use efficient rice cultivars through /sup 13/C isotope discrimination technique

    International Nuclear Information System (INIS)

    Akhtar, J.; Sabir, S.A.; Ashraf, M.Y.; Monneveux, P.; Serraj, R.

    2010-01-01

    Carbon isotope discrimination ('A') has been suggested as an indirect tool for selecting plants having higher water use efficiency (WUE) and yield potential. Enhancing WUE is an important breeding objective as water scarcity is increasing with every passing day. This study was undertaken to assess the genotypic variation and relationship between leaf, straw, grain 'A', grain yield and WUE in eight aromatic rice cultivars grown in lysimeters under three water regimes, in absence of drainage and runoff. Highly significant positive correlations were found between aboveground biomass and WUEB, and grain yield and WUEG, due to the low variation in water consumed by different cultivars. Leaf, straw and grain A showed a consistent variation across treatments and cultivars. Under water stress conditions, both leaf and straw 'A' were positively correlated to grain yield and WUEG. In all the water treatments, WUEG was positively correlated to harvest index and negatively to plant height. All the mutants from Basmati 385 had significantly higher 'A' values as compared to the mutants from Basmati 370. It was concluded that the new cultivar, Basmati 385, represents a better genetic source for 'A' improvement than the old cultivar, Basmati 370. (author)

  11. Effects of water turbidity and different temperatures on oxidative stress in caddisfly (Stenopsyche marmorata) larvae.

    Science.gov (United States)

    Suzuki, Jumpei; Imamura, Masahiro; Nakano, Daisuke; Yamamoto, Ryosuke; Fujita, Masafumi

    2018-07-15

    Anthropogenic water turbidity derived from suspended solids (SS) is caused by reservoir sediment management practices such as drawdown flushing. Turbid water induces stress in many aquatic organisms, but the effects of turbidity on oxidative stress responses in aquatic insects have not yet been demonstrated. Here, we examined antioxidant responses, oxidative damage, and energy reserves in caddisfly (Stenopsyche marmorata) larvae exposed to turbid water (0 mg SS L -1 , 500 mg SS L -1 , and 2000 mg SS L -1 ) at different temperatures. We evaluated the combined effects of turbid water and temperature by measuring oxidative stress and using metabolic biomarkers. No turbidity level was significantly lethal to S. marmorata larvae. Moreover, there were no significant differences in antioxidant response or oxidative damage between the control and turbid water treatments at a low temperature (10 °C). However, at a high temperature (25 °C), turbid water modulated the activity of the antioxidant enzymes superoxide dismutase and catalase and the oxygen radical absorbance capacity as an indicator of the redox state of the insect larvae. Antioxidant defenses require energy, and high temperature was associated with low energy reserves, which might limit the capability of organisms to counteract reactive oxygen species. Moreover, co-exposure to turbid water and high temperature caused fluctuation of antioxidant defenses and increased the oxidative damage caused by the production of reactive oxygen species. Furthermore, the combined effect of high temperature and turbid water on antioxidant defenses and oxidative damage was larger than the individual effects. Therefore, our results demonstrate that exposure to both turbid water and high temperature generates additive and synergistic interactions causing oxidative stress in this aquatic insect species. Copyright © 2018. Published by Elsevier B.V.

  12. Bayesian inference for the genetic control of water deficit tolerance in spring wheat by stochastic search variable selection.

    Science.gov (United States)

    Safari, Parviz; Danyali, Syyedeh Fatemeh; Rahimi, Mehdi

    2018-06-02

    Drought is the main abiotic stress seriously influencing wheat production. Information about the inheritance of drought tolerance is necessary to determine the most appropriate strategy to develop tolerant cultivars and populations. In this study, generation means analysis to identify the genetic effects controlling grain yield inheritance in water deficit and normal conditions was considered as a model selection problem in a Bayesian framework. Stochastic search variable selection (SSVS) was applied to identify the most important genetic effects and the best fitted models using different generations obtained from two crosses applying two water regimes in two growing seasons. The SSVS is used to evaluate the effect of each variable on the dependent variable via posterior variable inclusion probabilities. The model with the highest posterior probability is selected as the best model. In this study, the grain yield was controlled by the main effects (additive and non-additive effects) and epistatic. The results demonstrate that breeding methods such as recurrent selection and subsequent pedigree method and hybrid production can be useful to improve grain yield.

  13. Recent evolution of China's virtual water trade: analysis of selected crops and considerations for policy

    Science.gov (United States)

    Shi, J.; Liu, J.; Pinter, L.

    2013-09-01

    China has dramatically increased its virtual water import unconsciously for recent years. Many studies have focused on the quantity of traded virtual water but very few go into analysing geographic distribution and the properties of China's virtual water trade network. This paper provides a calculation and analysis of the crop-related virtual water trade network of China based on 27 major primary crops between 1986 and 2009. The results show that China is a net importer of virtual water from water-abundant areas of North and South America, and a net virtual water exporter to water-stressed areas of Asia, Africa, and Europe. Virtual water import is far larger than virtual water export and in both import and export a small number of trade partners control the supply chain. Grain crops are the major contributors to virtual water trade, and among grain crops soybeans, mostly imported from the US, Brazil and Argentina are the most significant. As crop yield and crop water productivity in North and South America are generally higher than those in Asia and Africa, the effect of China's crop-related virtual water trade positively contributes to optimizing crop water use efficiency at the global scale. In order to mitigate water scarcity and secure the food supply, virtual water should be actively incorporated into national water management strategies. From the national perspective, China should reduce the export and increase the import of water-intensive crops. But the sources of virtual water import need to be further diversified to reduce supply chain risks and increase resilience.

  14. Electrophysiological assessment of water stress in fruit-bearing woody plants.

    Science.gov (United States)

    Ríos-Rojas, Liliana; Tapia, Franco; Gurovich, Luis A

    2014-06-15

    Development and evaluation of a real-time plant water stress sensor, based on the electrophysiological behavior of fruit-bearing woody plants is presented. Continuous electric potentials are measured in tree trunks for different irrigation schedules, inducing variable water stress conditions; results are discussed in relation to soil water content and micro-atmospheric evaporative demand, determined continuously by conventional sensors, correlating this information with tree electric potential measurements. Systematic and differentiable patterns of electric potentials for water-stressed and no-stressed trees in 2 fruit species are presented. Early detection and recovery dynamics of water stress conditions can also be monitored with these electrophysiology sensors, which enable continuous and non-destructive measurements for efficient irrigation scheduling throughout the year. The experiment is developed under controlled conditions, in Faraday cages located at a greenhouse area, both in Persea americana and Prunus domestica plants. Soil moisture evolution is controlled using capacitance sensors and solar radiation, temperature, relative humidity, wind intensity and direction are continuously registered with accurate weather sensors, in a micro-agrometeorological automatic station located at the experimental site. The electrophysiological sensor has two stainless steel electrodes (measuring/reference), inserted on the stem; a high precision Keithley 2701 digital multimeter is used to measure plant electrical signals; an algorithm written in MatLab(®), allows correlating the signal to environmental variables. An electric cyclic behavior is observed (circadian cycle) in the experimental plants. For non-irrigated plants, the electrical signal shows a time positive slope and then, a negative slope after restarting irrigation throughout a rather extended recovery process, before reaching a stable electrical signal with zero slope. Well-watered plants presented a

  15. Field development. Concept selection in deep water environment offshore Angola

    Energy Technology Data Exchange (ETDEWEB)

    Guenot, A.; Berger, J.C.; Limet, N. [TotalFinaElf, la Defense 6, Rosa-Lirio Project Group, 92 - Courbevoie (France)

    2002-10-01

    The significant oil discoveries made at the end of the 90's in the deep water environment offshore the coast of Angola, has led to a considerable amount of development activities. The first field in production was the turnkey development of the Kuito field on the Block 14 operated by Chevron. More recently the Girassol field has been put successfully in production on the Block 17, operated by TotalFinaElf. Both developments are making use of sub-sea wells connected to a moored dedicated FPSO. On the western side of the Girassol field, several discoveries have been made. They are known as the Rosa Lirio pole, from the names of two of the main channels. Values for water depth are in the same range than on Girassol (1300- 1400 m). A project group has been established in 1999 to evaluate the development of these discoveries. The purpose of this paper is to present the conceptual work which as been carried out, and in particular to show that even if many different concepts have been evaluated, the final choice has been also to make use of sub-sea trees. (authors)

  16. Ground water in selected areas in the Klamath Basin, Oregon

    Science.gov (United States)

    Leonard, A.R.; Harris, A.B.

    1973-01-01

    GROUNDWATER FEATURES OF SIX LOWLAND AREAS IN THE KLAMATH BASIN OF OREGON--KLAMATH MARSH AREA, AND SPRAGUE RIVER, SWAN LAKE, YONNA, POE, AND LANGELL VALLEYS--ARE DESCRIBED. RUGGED MOUNTAINS AND RIDGES SURROUND AND SEPARATE THESE LOWLANDS WHERE FLOORS RANGE IN ALTITUDE FROM 4,100 FEET IN POE VALLEY TO 4,600 FEET NORTH OF KLAMATH MARSH. THE SIX AREAS EXTEND OVER A NORTH-SOUTH DISTANCE OF 70 MILES, AN EAST-WEST DISTANCE OF 40 MILES, AND INCLUDE AN AREA OF APPROXIMATELY 600 SQUARE MILES. THE AREA IS SEMIARID AND RECEIVED ABOUT 14 TO 18 INCHES OF PRECIPITATION A YEAR. EXTINCT VOLCANOES AND THEIR EXTRUSIONS CHARACTERIZE THE AREA. MOST WELLS TAP PERMEABLE BASALT OR CINDERY RUBBLE BENEATH THE LACUSTRINE BEDS. THE DEPTHS OF WELLS RANGE FROM LESS THAN 50 TO NEARLY 2,000 FEET--MOST ARE BETWEEN 100 AND 1,000 FEET DEEP. FLOWING WELLS OCCUR IN ALL AREAS EXCEPT SWAN LAKE VALLEY. THE MOST EXTENSIVE AREA OF FLOWING WELLS IS IN THE SPRAGUE RIVER VALLEY, WHERE ABOUT 25 WELLS, SOME FLOWING MORE THAN 2,000 GPM, SUPPLY WATER FOR IRRIGATION. WATER LEVELS IN WELLS FLUCTUATE SEASONALLY FROM 1 TO 4 FEET. GROUNDWATER IN THE BASIN IS OF EXCELLENT QUALITY FOR DRINKING, IRRIGATION, AND MOST INDUSTRIAL USES.

  17. Selective Synthesis of Manganese/Silicon Complexes in Supercritical Water

    Directory of Open Access Journals (Sweden)

    Jiancheng Wang

    2014-01-01

    Full Text Available A series of manganese salts (Mn(NO32, MnCl2, MnSO4, and Mn(Ac2 and silicon materials (silica sand, silica sol, and tetraethyl orthosilicate were used to synthesize Mn/Si complexes in supercritical water using a tube reactor. X-ray diffraction (XRD, X-ray photoelectron spectrometer (XPS, transmission electron microscopy (TEM, and scanning electron microscopy (SEM were employed to characterize the structure and morphology of the solid products. It was found that MnO2, Mn2O3, and Mn2SiO4 could be obtained in supercritical water at 673 K in 5 minutes. The roles of both anions of manganese salts and silicon species in the formation of manganese silicon complexes were discussed. The inorganic manganese salt with the oxyacid radical could be easily decomposed to produce MnO2/SiO2 and Mn2O3/SiO2. It is interesting to found that Mn(Ac2 can react with various types of silicon to produce Mn2SiO4. The hydroxyl groups of the SiO2 surface from different silicon sources enhance the reactivity of SiO2.

  18. Genetic Gains in Grain Yield of a Maize Population Improved through Marker Assisted Recurrent Selection under Stress and Non-stress Conditions in West Africa

    Directory of Open Access Journals (Sweden)

    Rekiya O. Abdulmalik

    2017-05-01

    Full Text Available Marker-assisted recurrent selection (MARS is a breeding method used to accumulate favorable alleles that for example confer tolerance to drought in inbred lines from several genomic regions within a single population. A bi-parental cross formed from two parents that combine resistance to Striga hermonthica with drought tolerance, which was improved through MARS, was used to assess changes in the frequency of favorable alleles and its impact on inbred line improvement. A total of 200 testcrosses of randomly selected S1 lines derived from the original (C0 and advanced selection cycles of this bi-parental population, were evaluated under drought stress (DS and well-watered (WW conditions at Ikenne and under artificial Striga infestation at Abuja and Mokwa in Nigeria in 2014 and 2015. Also, 60 randomly selected S1 lines each derived from the four cycles (C0, C1, C2, C3 were genotyped with 233 SNP markers using KASP assay. The results showed that the frequency of favorable alleles increased with MARS in the bi-parental population with none of the markers showing fixation. The gain in grain yield was not significant under DS condition due to the combined effect of DS and armyworm infestation in 2015. Because the parents used for developing the bi-parental cross combined tolerance to drought with resistance to Striga, improvement in grain yield under DS did not result in undesirable changes in resistance to the parasite in the bi-parental maize population improved through MARS. MARS increased the mean number of combinations of favorable alleles in S1 lines from 114 in C0 to 124 in C3. The level of heterozygosity decreased by 15%, while homozygosity increased by 13% due to the loss of some genotypes in the population. This study demonstrated the effectiveness of MARS in increasing the frequency of favorable alleles for tolerance to drought without disrupting the level of resistance to Striga in a bi-parental population targeted as a source of improved

  19. Genetic Gains in Grain Yield of a Maize Population Improved through Marker Assisted Recurrent Selection under Stress and Non-stress Conditions in West Africa.

    Science.gov (United States)

    Abdulmalik, Rekiya O; Menkir, Abebe; Meseka, Silvestro K; Unachukwu, Nnanna; Ado, Shehu G; Olarewaju, Joseph D; Aba, Daniel A; Hearne, Sarah; Crossa, Jose; Gedil, Melaku

    2017-01-01

    Marker-assisted recurrent selection (MARS) is a breeding method used to accumulate favorable alleles that for example confer tolerance to drought in inbred lines from several genomic regions within a single population. A bi-parental cross formed from two parents that combine resistance to Striga hermonthica with drought tolerance, which was improved through MARS, was used to assess changes in the frequency of favorable alleles and its impact on inbred line improvement. A total of 200 testcrosses of randomly selected S 1 lines derived from the original (C 0 ) and advanced selection cycles of this bi-parental population, were evaluated under drought stress (DS) and well-watered (WW) conditions at Ikenne and under artificial Striga infestation at Abuja and Mokwa in Nigeria in 2014 and 2015. Also, 60 randomly selected S 1 lines each derived from the four cycles (C 0 , C 1 , C 2 , C 3 ) were genotyped with 233 SNP markers using KASP assay. The results showed that the frequency of favorable alleles increased with MARS in the bi-parental population with none of the markers showing fixation. The gain in grain yield was not significant under DS condition due to the combined effect of DS and armyworm infestation in 2015. Because the parents used for developing the bi-parental cross combined tolerance to drought with resistance to Striga , improvement in grain yield under DS did not result in undesirable changes in resistance to the parasite in the bi-parental maize population improved through MARS. MARS increased the mean number of combinations of favorable alleles in S 1 lines from 114 in C 0 to 124 in C 3 . The level of heterozygosity decreased by 15%, while homozygosity increased by 13% due to the loss of some genotypes in the population. This study demonstrated the effectiveness of MARS in increasing the frequency of favorable alleles for tolerance to drought without disrupting the level of resistance to Striga in a bi-parental population targeted as a source of improved

  20. Rearing Water Treatment Induces Microbial Selection Influencing the Microbiota and Pathogen Associated Transcripts of Cod (Gadus morhua Larvae

    Directory of Open Access Journals (Sweden)

    Ragnhild I. Vestrum

    2018-05-01

    Full Text Available We have previously shown that K-selection and microbial stability in the rearing water increases survival and growth of Atlantic cod (Gadus morhua larvae, and that recirculating aquaculture systems (RAS are compatible with this. Here, we have assessed how water treatment influenced the larval microbiota and host responses at the gene expression level. Cod larvae were reared with two different rearing water systems: a RAS and a flow-through system (FTS. The water microbiota was examined using a 16S rDNA PCR/DGGE strategy. RNA extracted from larvae at 8, 13, and 17 days post hatching was used for microbiota and microarray gene expression analysis. Bacterial cDNA was synthesized and used for 16S rRNA amplicon 454 pyrosequencing of larval microbiota. Both water and larval microbiota differed significantly between the systems, and the larval microbiota appeared to become more dissimilar between systems with time. In total 4 phyla were identified for all larvae: Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria. The most profound difference in larval microbiota was a high abundance of Arcobacter (Epsilonproteobacteria in FTS larvae (34 ± 9% of total reads. Arcobacter includes several species that are known pathogens for humans and animals. Cod larval transcriptome responses were investigated using an oligonucleotide gene expression microarray covering approximately 24,000 genes. Interestingly, FTS larvae transcriptional profiles revealed an overrepresentation of upregulated transcripts associated with responses to pathogens and infections, such as c1ql3-like, pglyrp-2-like and zg16, compared to RAS larvae. In conclusion, distinct water treatment systems induced differences in the larval microbiota. FTS larvae showed up-regulation of transcripts associated with responses to microbial stress. These results are consistent with the hypothesis that RAS promotes K-selection and microbial stability by maintaining a microbial load close to the

  1. On the interaction of UV-B radiation (280-315 mm) with water stress in crop plants

    International Nuclear Information System (INIS)

    Balakumar, T.; Vincent, V.H.B.; Paliwal, K.

    1993-01-01

    Cowpea (Vigna unguiculata L. Walp.) seedlings (3-day-old) were subjected to 4 kinds of experimental treatments: (1) control without exposure to any stress (-D-UV), (2) moderate water stress with no UV-B irradiation (+D-UV), (3) no water stress but exposure to UV-B radiation (-D+UV), and (4) moderate water stress and exposure to UV-B (+D+UV). UV-B and drought stress in the combined form elicited beneficial effects on the morphological and growth characteristics, and a few additive inhibitory effects in some functional processes. An increase in the specific leaf weight (SLW) was observed in the combination of stresses, which could be a defence mechanism against UV-B. The combination of stresses promoted the synthesis of anthocyanins and phenolic compounds. The responses of plants to the combination of stresses indicate that during simultaneous exposure of plants to multiple stresses, one form of stress could minimize the damage by the other. The enhancement of superoxide dismutase (SOD) and catalase activities appear to serve as acclimation mechanisms to scavenge the toxic, free radicals of oxygen produced under stress conditions. However, the inhibition in nitrate metabolism was greater in the combined stresses than in either of the stresses imposed separately. The results of this study illustrate that the interaction of stresses during simultaneous multiple stress conditions brings out certain beneficial effects. (author)

  2. Effect of seasonal and long-term changes in stress on sources of water to wells

    Science.gov (United States)

    Reilly, Thomas E.; Pollock, David W.

    1995-01-01

    The source of water to wells is ultimately the location where the water flowing to a well enters the boundary surface of the ground-water system . In ground-water systems that receive most of their water from areal recharge, the location of the water entering the system is at the water table . The area contributing recharge to a discharging well is the surface area that defines the location of the water entering the groundwater system. Water entering the system at the water table flows to the well and is eventually discharged from the well. Many State agencies are currently (1994) developing wellhead-protection programs. The thrust of some of these programs is to protect water supplies by determining the areas contributing recharge to water-supply wells and by specifying regulations to minimize the opportunity for contamination of the recharge water by activities at the land surface. In the analyses of ground-water flow systems, steady-state average conditions are frequently used to simplify the problem and make a solution tractable. Recharge is usually cyclic in nature, however, having seasonal cycles and longer term climatic cycles. A hypothetical system is quantitatively analyzed to show that, in many cases, these cyclic changes in the recharge rates apparently do not significantly affect the location and size of the areas contributing recharge to wells. The ratio of the mean travel time to the length of the cyclic stress period appears to indicate whether the transient effects of the cyclic stress must be explicitly represented in the analysis of contributing areas to wells. For the cases examined, if the ratio of the mean travel time to the period of the cyclic stress was much greater than one, then the transient area contributing recharge to wells was similar to the area calculated using an average steady-state condition. Noncyclic long-term transient changes in water use, however, and cyclic stresses on systems with ratios less than 1 can and do affect the

  3. Accuracy and simultaneous selection gains for N-stress tolerance and N-use efficiency in maize tropical lines

    Directory of Open Access Journals (Sweden)

    Leandro de Freitas Mendonça

    Full Text Available ABSTRACT Maize plants can be N-use efficient or N-stress tolerant. The first have high yields in favorable environments but is drastically affected under stress conditions; whereas the second show satisfactory yields in stressful environments but only moderate ones under optimal conditions. In this context, our aim was to assess the possibility of selecting tropical maize lines that are simultaneously N-stress tolerant and N-use efficient and check for differences between simultaneous selection statistical methods. Sixty-four tropical maize lines were evaluated for Nitrogen Agronomic Efficiency (NAE and Low Nitrogen Tolerance (LNTI response indices and two per se selection indices, Low Nitrogen Agronomic Efficiency (LNAE and Harmonic Mean of Relative Performance (HMRP. We performed eight selection scenarios: LNAE; HMRP; Additive index; Mulamba-Mock index; and Independent culling levels. The last three was predicted by REML/BLUP single-trait and multi-trait using genotypic values of NAE and LNTI. The REML/BLUP multi-trait analysis was superior to the single-trait analysis due to high unfavorable correlation between NAE and LNTI. However, the accuracy and genotypic determination coefficient of NAE and LNTI were too low. Thus, neither single- nor multi-trait analysis achieved a good result for simultaneous selection nor N-use efficiency nor N-stress tolerance. LNAE obtained satisfactorily accurate values and genotypic determination coefficient, but its performance in selection gain was worse than HMRP, particularly in terms of N-use efficiency. Therefore, because of the superior performance in accuracy, genotypic determination coefficient and selection, HMRP was considered the best simultaneous selection methodology of the scenarios tested for N-use efficiency and N-stress tolerance.

  4. Mice selected for high versus low stress reactivity: a new animal model for affective disorders.

    Science.gov (United States)

    Touma, Chadi; Bunck, Mirjam; Glasl, Lisa; Nussbaumer, Markus; Palme, Rupert; Stein, Hendrik; Wolferstätter, Michael; Zeh, Ramona; Zimbelmann, Marina; Holsboer, Florian; Landgraf, Rainer

    2008-07-01

    Affective disorders such as major depression are among the most prevalent and costly diseases of the central nervous system, but the underlying mechanisms are still poorly understood. In recent years, it has become evident that alterations of the stress hormone system, in particular dysfunctions (hyper- or hypo-activity) of the hypothalamic-pituitary-adrenal (HPA) axis, play a prominent role in the development of major depressive disorders. Therefore, we aimed to generate a new animal model comprising these neuroendocrine core symptoms in order to unravel parameters underlying increased or decreased stress reactivity. Starting from a population of outbred mice (parental generation: 100 males and 100 females of the CD-1 strain), two breeding lines were established according to the outcome of a 'stress reactivity test' (SRT), consisting of a 15-min restraint period and tail blood samplings immediately before and after exposure to the stressor. Mice showing a very high or a very low secretion of corticosterone in the SRT, i.e. animals expressing a hyper- or a hypo-reactivity of the HPA axis, were selected for the 'high reactivity' (HR) and the 'low reactivity' (LR) breeding line, respectively. Additionally, a third breeding line was established consisting of animals with an 'intermediate reactivity' (IR) in the SRT. Already in the first generation, i.e. animals derived from breeding pairs selected from the parental generation, significant differences in the reactivity of the HPA axis between HR, IR, and LR mice were observed. Moreover, these differences were found across all subsequent generations and could be increased by selective breeding, which indicates a genetic basis of the respective phenotype. Repeated testing of individuals in the SRT furthermore proved that the observed differences in stress responsiveness are present already early in life and can be regarded as a robust genetic predisposition. Tests investigating the animal's emotionality including anxiety

  5. Selective and context-dependent effects of chemical stress across trophic levels at the basis of marine food webs.

    Science.gov (United States)

    Mensens, Christoph; De Laender, Frederik; Janssen, Colin R; Rivera, Frances Camille; Sabbe, Koen; De Troch, Marleen

    2018-04-26

    Human activities increasingly impact the functioning of marine food webs, but anthropogenic stressors are seldom included in ecological study designs. Diet quality, as distinct from just diet quantity, has moreover rarely been highlighted in food web studies in a stress context. We measured the effects of metal and pesticide stress (copper and atrazine) on the contribution of a benthic intertidal diatom community to two processes that are key to the functioning of intertidal systems: biomass (diet quantity) and lipid (diet quality) production. We then examined if stressors affected diatom functioning by selectively targeting the species contributing most to functioning (selective stress effects) or by changing the species' functional contribution (context-dependent effects). Finally, we tested if stress-induced changes in diet quality altered the energy flow to the diatoms' main grazers (harpacticoid copepods). Diatom diet quantity was reduced by metal stress but not by low pesticide levels due to the presence of an atrazine-tolerant, mixotrophic species. Selective effects of the pesticide reduced diatom diet quality by 60% and 75% at low and high pesticide levels respectively, by shifting diatom community structure from dominance by lipid-rich species toward dominance by an atrazine-tolerant, but lipid-poor, species. Context-dependent effects did not affect individual diatom lipid content at low levels of both stressors, but caused diatoms to lose 40% of their lipids at high copper stress. Stress-induced changes in diet quality predicted the energy flow from the diatoms to their copepod consumers, which lost half of their lipids when feeding on diatoms grown under low and high pesticide and high metal stress. Selective pesticide effects were a more important threat for trophic energy transfer than context-dependent effects of both stressors, with shifts in diatom community structure affecting the energy flow to their copepod grazers at stress levels where no

  6. Water stress and social vulnerability in the southern United States, 2010-2040

    Science.gov (United States)

    cassandra Johnson-Gaither; John Schelhas; Wayne Zipperer; Ge Sun; Peter V. Caldwell; Neelam Poudyal

    2014-01-01

    Water scarcities are striking in semiarid, subregions of the Southern United States such as Oklahoma and western Texas (Glennon 2009, Sabo et al. 2010). In Texas, water stress has been a constant concern since the 1950s when the state experienced severe drought conditions (Moore 2005). The nearly 2000-mile Rio Grande River, which forms part of the Texas–Mexico border,...

  7. Stress-inducible expression of At DREB1A in transgenic peanut (Arachis hypogaea L.) increases transpiration efficiency under water-limiting conditions.

    Science.gov (United States)

    Bhatnagar-Mathur, Pooja; Devi, M Jyostna; Reddy, D Srinivas; Lavanya, M; Vadez, Vincent; Serraj, R; Yamaguchi-Shinozaki, K; Sharma, Kiran K

    2007-12-01

    Water deficit is the major abiotic constraint affecting crop productivity in peanut (Arachis hypogaea L.). Water use efficiency under drought conditions is thought to be one of the most promising traits to improve and stabilize crop yields under intermittent water deficit. A transcription factor DREB1A from Arabidopsis thaliana, driven by the stress inducible promoter from the rd29A gene, was introduced in a drought-sensitive peanut cultivar JL 24 through Agrobacterium tumefaciens-mediated gene transfer. The stress inducible expression of DREB1A in these transgenic plants did not result in growth retardation or visible phenotypic alterations. T3 progeny of fourteen transgenic events were exposed to progressive soil drying in pot culture. The soil moisture threshold where their transpiration rate begins to decline relative to control well-watered (WW) plants and the number of days needed to deplete the soil water was used to rank the genotypes using the average linkage cluster analysis. Five diverse events were selected from the different clusters and further tested. All the selected transgenic events were able to maintain a transpiration rate equivalent to the WW control in soils dry enough to reduce transpiration rate in wild type JL 24. All transgenic events except one achieved higher transpiration efficiency (TE) under WW conditions and this appeared to be explained by a lower stomatal conductance. Under water limiting conditions, one of the selected transgenic events showed 40% higher TE than the untransformed control.

  8. Evaluation of water stress and groundwater storage using a global hydrological model

    Science.gov (United States)

    Shiojiri, D.; Tanaka, K.; Tanaka, S.

    2017-12-01

    United Nations reported the number of people will reach 9.7 billion in 2050, and this rapid growth of population will increase water use. To prevent global water shortage, it is important to identify the problematic areas in order to maintain water resources sustainability. Moreover, groundwater availability is decreasing in some areas due to excessive groundwater extraction compared to the groundwater recharge capacity. The development of a hydrological model that can simulate the current status of the world's water resources represents an important tool to achieve sustainable water resources management. In this study, a global hydrological simulation is conducted at a 20km spatial resolution using the land surface model SiBUC, which is coupled to the river routing model HydroBEAM. In the river routing model, we evaluate water stress by comparing the excess of water demand with the river water demand. Areas with high water stress are seen in United States, India, and east part of China; however, for the case of Africa the overall water stress is zero. This could be because rain-fed agriculture is the norm in Africa and thus irrigation water demand is low, which affects water stress index. Sustainability of groundwater resources is also evaluated in the river routing model by setting a virtual groundwater tank. When the amount of groundwater withdrawal constantly exceeds groundwater recharge, the volume in the tank falls below zero and the area is regarded as unsustainable in terms of groundwater usage. Such areas are mostly seen in central United States, northeast China, the region between northwest India and Pakistan. In the simulation with SiBUC, the amount of groundwater recharge is assumed as the proportion of water that flows from the second to the third soil layer. This proportion will be estimated by comparing monthly variations of terrestrial water storage (TWS) derived from the observations of the GRACE satellite with the simulated TWS variations. From

  9. A randomized trial on mineralocorticoid receptor blockade in men: effects on stress responses, selective attention, and memory.

    Science.gov (United States)

    Cornelisse, Sandra; Joëls, Marian; Smeets, Tom

    2011-12-01

    Corticosteroids, released in high amounts after stress, exert their effects via two different receptors in the brain: glucocorticoid receptors (GRs) and mineralocorticoid receptors (MRs). GRs have a role in normalizing stress-induced effects and promoting consolidation, while MRs are thought to be important in determining the threshold for activation of the hypothalamic-pituitary-adrenal (HPA) axis. We investigated the effects of MR blockade on HPA axis responses to stress and stress-induced changes in cognitive function. In a double-blind, placebo-controlled study, 64 healthy young men received 400 mg of the MR antagonist spironolactone or placebo. After 1.5 h, they were exposed to either a Trier Social Stress Test or a non-stressful control task. Responses to stress were evaluated by hormonal, subjective, and physiological measurements. Afterwards, selective attention, working memory, and long-term memory performance were assessed. Spironolactone increased basal salivary cortisol levels as well as cortisol levels in response to stress. Furthermore, spironolactone significantly impaired selective attention, but only in the control group. The stress group receiving spironolactone showed impaired working memory performance. By contrast, long-term memory was enhanced in this group. These data support a role of MRs in the regulation of the HPA axis under basal conditions as well as in response to stress. The increased availability of cortisol after spironolactone treatment implies enhanced GR activation, which, in combination with MR blockade, presumably resulted in a decreased MR/GR activation ratio. This condition influences both selective attention and performance in various memory tasks.

  10. Possible role of selective serotonin reuptake inhibitor sertraline on oxidative stress responses.

    Science.gov (United States)

    Battal, D; Yalin, S; Eker, E D; Aktas, A; Sahin, N O; Cebo, M; Berköz, M

    2014-01-01

    The naphthylamine derivative sertraline is a potent and selective inhibitor of serotonin reuptake into presynaptic terminals and the most widely used that has been shown to have both antidepressant and antianxiety effects. In the present study the possible role of sertraline (acute and chronically doses) was evaluated on lipid peroxidation levels and antioxidant enzyme activities in plasma and brain tissues of (10, 40, 80 mg/kg) sertraline treated Wistar albino rats (n=48). Lipid peroxidation levels (MDA) of plasma and brain tissue increased in all acute and chronic sertraline treated rats (p Catalase (CAT) levels of plasma and brain tissue and paraoxonase (PON) levels of plasma decreased (p < 0.05) as compared with vehicle group. Based on the data, it can be concluded that high dose sertraline administration enhances oxidative stress. Therefore, dose adjustment in depression patients seems significant as it may help prevention of further prognosis of the diseases.

  11. An improved water budget for the El Yunque National Forest, Puerto Rico, as determined by the Water Supply Stress Index Model

    Science.gov (United States)

    Liangxia Zhang; Ge Sun; Erika Cohen; Steven McNulty; Peter Caldwell; Suzanne Krieger; Jason Christian; Decheng Zhou; Kai Duan; Keren J. Cepero-Pérez

    2018-01-01

    Quantifying the forest water budget is fundamental to making science-based forest management decisions. This study aimed at developing an improved water budget for the El Yunque National Forest (ENF) in Puerto Rico, one of the wettest forests in the United States. We modified an existing monthly scale water balance model, Water Supply Stress Index (WaSSI), to reflect...

  12. Repeated Thermal Stress, Shading, and Directional Selection in the Florida Reef Tract

    Directory of Open Access Journals (Sweden)

    Robert van Woesik

    2017-06-01

    Full Text Available Over the last three decades reef corals have been subjected to an unprecedented frequency and intensity of thermal-stress events, which have led to extensive coral bleaching, disease, and mortality. Over the next century, the climate is predicted to drive sea-surface temperatures to even higher levels, consequently increasing the risk of mass bleaching and disease outbreaks. Yet, there is considerable temporal and spatial variation in coral bleaching and in disease prevalence. Using data collected from 2,398 sites along the Florida reef tract from 2005 to 2015, this study examined the temporal and spatial patterns of coral bleaching and disease in relation to coral-colony size, depth, temperature, and chlorophyll-a concentrations. The results show that coral bleaching was most prevalent during the warmest years in 2014 and 2015, and disease was also most prevalent in 2010, 2014, and 2015. Although the majority of the corals surveyed were found in habitats with low chlorophyll-a concentrations, and high irradiance, these same habitats showed the highest prevalence of coral bleaching and disease outbreaks during thermal-stress events. These results suggest that directional selection in a warming ocean may favor corals able to tolerate inshore, shaded environments with high turbidity and productivity.

  13. [The evaluation of selected oxidative stress parameters in patients with hyperthyroidism].

    Science.gov (United States)

    Andryskowski, Grzegorz; Owczarek, Tomasz

    2007-07-01

    Hyperthyroidism induces the acceleration of the basic metabolism and increases cellular oxygen utilization, consequently intensifies reactive oxygen species production and disturbs the oxidant-antioxidant balance. The objective of this study was to evaluate the selected oxidative stress parameters in patients with hyperthyroidism by analysis of the reactive oxygen species neutralizing enzymes activity--superoxide dismutase (SOD), glutathione peroxidase (GSHPx) and catalase (CAT), the estimation of free radical processes intensity--concentration of malondialdehyde (MDA), sulfhydryl groups (SH) in proteins and by quantification of the serum total antioxidant status (TAS). . Twenty-seven patients treated for hyperthyroidism and 12 healthy individuals were enrolled in the study. Enzyme activity (SOD, GSHPx, CAT), MDA and concentration of SH groups were analysed in erythrocytes, while TAS was measured in serum. Patients with hyperthyroidism compared with healthy subjects were characterized by a higher GSHPx activity in erythrocytes, lower serum TAS, the lower content of SH groups in proteins and the lower MDA concentration in erythrocytes. Our results suggest that hyperthyroidism increases oxidative stress and disturbs oxidant-antioxidant balance in the body. Thyreostatic treatment, if not leads to whole metabolic compensation, may only reduce oxidant-antioxidant disorders, however is not able to eliminate them entirely.

  14. Selective Breeding under Saline Stressed Conditions of Canola Mutations Induced by Gamma Rays

    International Nuclear Information System (INIS)

    Amer, I.M.; Moustafa, H.A.M.; Mansour, M.F.

    2009-01-01

    Mutation breeding program has been initiated for inducing canola mutations tolerance to saline stressed conditions for growing at harsh land in Egypt. Therefore, seed lots of three cultivars and exotic variety (Bactol, Serow 4, Serow 6 and Evita) were subjected to 100,400 and 600 Gy of gamma rays. Mass selection with 20 % intensity for high number of pods per plant has been done in each treatment in M2 generation. However, individually plants with high number of pods / plant were selected from each variety in M3 generation for test under saline stressed conditions at Ras Sudr region in M4 (8600 and 8300 ppm salinity for soil and irrigation, respectively). The obtained results revealed that eight mutated families from 12- test families in M4 generation surpassed their parents in seed yield / plant and related characters ( plant height ,fruiting zone length , No. of branches , No. of pods / plant ). In addition, the mutant F93 characterized by fast growing and non shuttering pods reflecting 50.4% over Evita control in seed yield/ plant. Twelve mutant lines in M5 represented the mutant families were grown in sandy-loam soil at Inshas region. The three mutant lines (L 22, L 38 and L 45) continuously surpassed their parents in seed yield and related characters, but the increases were less than the previous generation. The increase was 22.3 %, 38.7 % and 36.7 % over seed yield of respective parents. Moreover, mutant L66 exhibited an increase in its yield components in M5 at Inshas only, suggesting that gene expression and genomic structure extremely influenced by environmental factors. Genetic stability for the obtained mutations could be done at different environmental conditions in further studies

  15. Potential of duckweed (Lemna minor) for removal of nitrogen and phosphorus from water under salt stress.

    Science.gov (United States)

    Liu, Chunguang; Dai, Zheng; Sun, Hongwen

    2017-02-01

    Duckweed plays a major role in the removal of nitrogen (N) and phosphorus (P) from water. To determine the effect of salt stress on the removal of N and P by duckweed, we cultured Lemna minor, a common species of duckweed, in N and P-rich water with NaCl concentrations ranging from 0 to 100 mM for 24 h and 72 h, respectively. The results show that the removal capacity of duckweed for N and P was reduced by salt stress. Higher salt stress with longer cultivation period exerts more injury to duckweed and greater inhibition of N and P removal. Severe salt stress (100 mM NaCl) induced duckweed to release N and P and even resulted in negative removal efficiencies. The results indicate that L. minor should be used to remove N and P from water with salinities below 75 mM NaCl, or equivalent salt stress. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Modelling Water Stress in a Shiraz Vineyard Using Hyperspectral Imaging and Machine Learning

    Directory of Open Access Journals (Sweden)

    Kyle Loggenberg

    2018-01-01

    Full Text Available The detection of water stress in vineyards plays an integral role in the sustainability of high-quality grapes and prevention of devastating crop loses. Hyperspectral remote sensing technologies combined with machine learning provides a practical means for modelling vineyard water stress. In this study, we applied two ensemble learners, i.e., random forest (RF and extreme gradient boosting (XGBoost, for discriminating stressed and non-stressed Shiraz vines using terrestrial hyperspectral imaging. Additionally, we evaluated the utility of a spectral subset of wavebands, derived using RF mean decrease accuracy (MDA and XGBoost gain. Our results show that both ensemble learners can effectively analyse the hyperspectral data. When using all wavebands (p = 176, RF produced a test accuracy of 83.3% (KHAT (kappa analysis = 0.67, and XGBoost a test accuracy of 80.0% (KHAT = 0.6. Using the subset of wavebands (p = 18 produced slight increases in accuracy ranging from 1.7% to 5.5% for both RF and XGBoost. We further investigated the effect of smoothing the spectral data using the Savitzky-Golay filter. The results indicated that the Savitzky-Golay filter reduced model accuracies (ranging from 0.7% to 3.3%. The results demonstrate the feasibility of terrestrial hyperspectral imagery and machine learning to create a semi-automated framework for vineyard water stress modelling.

  17. Abscisic Acid Metabolism in Relation to Water Stress and Leaf Age in Xanthium strumarium1

    Science.gov (United States)

    Cornish, Katrina; Zeevaart, Jan A.D.

    1984-01-01

    Intact plants of Xanthium strumarium L. were subjected to a water stress-recovery cycle. As the stress took effect, leaf growth ceased and stomatal resistance increased. The mature leaves then wilted, followed by the half expanded ones. Water, solute, and pressure potentials fell steadily in all leaves during the rest of the stress period. After 3 days, the young leaves lost turgor and the plants were rewatered. All the leaves rapidly regained turgor and the younger ones recommenced elongation. Stomatal resistance declined, but several days elapsed before pre-stress values were attained. Abscisic acid (ABA) and phaseic acid (PA) levels rose in all the leaves after the mature ones wilted. ABA-glucose ester (ABA-GE) levels increased to a lesser extent, and the young leaves contained little of this conjugate. PA leveled off in the older leaves during the last 24 hours of stress, and ABA levels declined slightly. The young leaves accumulated ABA and PA throughout the stress period and during the 14-hour period immediately following rewatering. The ABA and PA contents, expressed per unit dry weight, were highest in the young leaves. Upon rewatering, large quantities of PA appeared in the mature leaves as ABA levels fell to the pre-stress level within 14 hours. In the half expanded and young leaves, it took several days to reach pre-stress ABA values. ABA-GE synthesis ceased in the mature leaves, once the stress was relieved, but continued in the half expanded and young leaves for 2 days. Mature leaves, when detached and stressed, accumulated an amount of ABA similar to that in leaves on the intact plant. In contrast, detached and stressed young leaves produced little ABA. Detached mature leaves, and to a lesser extent the half expanded ones, rapidly catabolized ABA to PA and ABA-GE, but the young leaves did not. Studies with radioactive (±)-ABA indicated that in young leaves the conversion of ABA to PA took place at a much lower rate than in mature ones. Leaves of all

  18. Abscisic Acid Metabolism in Relation to Water Stress and Leaf Age in Xanthium strumarium.

    Science.gov (United States)

    Cornish, K; Zeevaart, J A

    1984-12-01

    Intact plants of Xanthium strumarium L. were subjected to a water stress-recovery cycle. As the stress took effect, leaf growth ceased and stomatal resistance increased. The mature leaves then wilted, followed by the half expanded ones. Water, solute, and pressure potentials fell steadily in all leaves during the rest of the stress period. After 3 days, the young leaves lost turgor and the plants were rewatered. All the leaves rapidly regained turgor and the younger ones recommenced elongation. Stomatal resistance declined, but several days elapsed before pre-stress values were attained.Abscisic acid (ABA) and phaseic acid (PA) levels rose in all the leaves after the mature ones wilted. ABA-glucose ester (ABA-GE) levels increased to a lesser extent, and the young leaves contained little of this conjugate. PA leveled off in the older leaves during the last 24 hours of stress, and ABA levels declined slightly. The young leaves accumulated ABA and PA throughout the stress period and during the 14-hour period immediately following rewatering. The ABA and PA contents, expressed per unit dry weight, were highest in the young leaves. Upon rewatering, large quantities of PA appeared in the mature leaves as ABA levels fell to the pre-stress level within 14 hours. In the half expanded and young leaves, it took several days to reach pre-stress ABA values. ABA-GE synthesis ceased in the mature leaves, once the stress was relieved, but continued in the half expanded and young leaves for 2 days.Mature leaves, when detached and stressed, accumulated an amount of ABA similar to that in leaves on the intact plant. In contrast, detached and stressed young leaves produced little ABA. Detached mature leaves, and to a lesser extent the half expanded ones, rapidly catabolized ABA to PA and ABA-GE, but the young leaves did not. Studies with radioactive (+/-)-ABA indicated that in young leaves the conversion of ABA to PA took place at a much lower rate than in mature ones. Leaves of all

  19. Xanthophylls and abscisic acid biosynthesis in water-stressed bean leaves

    International Nuclear Information System (INIS)

    Li, Y.; Walton, D.C.

    1987-01-01

    Experiments were designed to obtain evidence about the possible role of xanthophylls as abscisic acid (ABA) precursors in water-stressed leaves of Phaseolus vularis L. Leaves were exposed to 14 CO 2 and the specific activities of several major leaf xanthophylls and stress-induced ABA were determined after a chase in 12 CO 2 for varying periods of time. The ABA specific radioactivities were about 30 to 70% of that of lutein and violaxanthin regardless of the chase period. The specific activity of neoxanthin, however, was only about 15% of that of ABA. The effects of fluridone on xanthophyll and ABA levels and the extent of labeling of both from 14 CO 2 were determined. Fluridone did not inhibit the accumulation of ABA when leaves were stressed once, although subsequent stresses in the presence of fluridone did lead to a reduced ABA accumulation. The incorporation of 14 C from 14 CO 2 into ABA and the xanthophylls was inhibited by fluridone and to about the same extent. The incorporation of 18 O into ABA from violaxanthin which had been labeled in situ by means of the violaxanthin cycle was measured. The results indicated that a portion of the ABA accumulated during stress was formed from violaxanthin which had been labeled with 18 O. The results of these experiments are consistent with a preformed xanthophyll(s) as the major ABA precursor in water-stressed bean leaves

  20. In silico analysis of ESTs from roots of Rangpur lime (Citrus limonia Osbeck under water stress

    Directory of Open Access Journals (Sweden)

    Raquel L. Boscariol-Camargo

    2007-01-01

    Full Text Available CitEST project resulted in the construction of cDNA libraries from different Citrus sp. tissues under various physiological conditions. Among them, plantlets of Rangpur lime were exposed to hydroponic conditions with and without water stress using PEG6000. RNA from roots was obtained and generated a total of 4,130 valid cDNA reads, with 2,020 from the non-stressed condition and 2,110 from the stressed set. Bioinformatic analyses measured the frequency of each read in the libraries and yielded an in silico transcriptional profile for each condition. A total of 40 contigs were differentially expressed and allowed to detect up-regulated homologue sequences to well known genes involved in stress response, such as aquaporins, dehydrin, sucrose synthase, and proline-related synthase. Some sequences could not be classified by using FunCat and remained with an unknown function. A large number of sequences presented high similarities to annotated genes involved with cell energy, protein synthesis and cellular transport, suggesting that Rangpur lime may sustain active cell growth under stressed condition. The presence of membrane transporters and cell signaling components could be an indication of a coordinated morphological adaptation and biochemical response during drought, helping to explain the higher tolerance of this rootstock to water stress.

  1. Xanthophylls and abscisic acid biosynthesis in water-stressed bean leaves

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y.; Walton, D.C.

    1987-12-01

    Experiments were designed to obtain evidence about the possible role of xanthophylls as abscisic acid (ABA) precursors in water-stressed leaves of Phaseolus vularis L. Leaves were exposed to /sup 14/CO/sub 2/ and the specific activities of several major leaf xanthophylls and stress-induced ABA were determined after a chase in /sup 12/CO/sub 2/ for varying periods of time. The ABA specific radioactivities were about 30 to 70% of that of lutein and violaxanthin regardless of the chase period. The specific activity of neoxanthin, however, was only about 15% of that of ABA. The effects of fluridone on xanthophyll and ABA levels and the extent of labeling of both from /sup 14/CO/sub 2/ were determined. Fluridone did not inhibit the accumulation of ABA when leaves were stressed once, although subsequent stresses in the presence of fluridone did lead to a reduced ABA accumulation. The incorporation of /sup 14/C from /sup 14/CO/sub 2/ into ABA and the xanthophylls was inhibited by fluridone and to about the same extent. The incorporation of /sup 18/O into ABA from violaxanthin which had been labeled in situ by means of the violaxanthin cycle was measured. The results indicated that a portion of the ABA accumulated during stress was formed from violaxanthin which had been labeled with /sup 18/O. The results of these experiments are consistent with a preformed xanthophyll(s) as the major ABA precursor in water-stressed bean leaves.

  2. Towards Estimating Water Stress through Leaf and Canopy Water Content Derived from Optical and Thermal Hyperspectral Data

    Science.gov (United States)

    Corbin, Amie; Timmermans, Joris; van der Tol, Christiaan; Verhoef, Wout

    2015-04-01

    A competition for available (drinkable) water has arisen. This competition originated due to increasing global population and the respective needs of this population. The water demand for human consumption and irrigation of food producing crops and biofuel related vegetation, has led to early indication of drought as a key issue in many studies. However, while drought monitoring systems might provide some reasonable predictions, at the time of visible symptoms of plant stress, a plant may already be critically affected. Consequently, pre-symptomatic non-destructive monitoring of plants is needed. In many studies of plant stress, this is performed by examining internal plant physiology through existing remote sensing techniques, with varying applications. However, a uniform remote sensing method for identifying early plant stress under drought conditions is still developing. In some instances, observations of vegetation water content are used to assess the impact of soil water deficit on the health of a plant or canopy. When considering water content as an indicator of water stress in a plant, this comments not only on the condition of the plant itself, but also provides indicators of photosynthetic activity and the susceptibility to drought. Several indices of canopy health currently exists (NDVI, DVI, SAVI, etc.) using optical and near infrared reflectance bands. However, these are considered inadequate for vegetation health investigations because such semi-empirical models result in less accuracy for canopy measurements. In response, a large amount of research has been conducted to estimate canopy health directly from considering the full spectral behaviour. In these studies , the canopy reflectance has been coupled to leaf parameters, by using coupling leaf radiative transfer models (RTM), such as PROSPECT, to a canopy RTM such as SAIL. The major shortcomings of these researches is that they have been conducted primarily for optical remote sensing. Recently

  3. Selection of spatial scale for assessing impacts of groundwater-based water supply on freshwater resources

    DEFF Research Database (Denmark)

    Hybel, Anne-Marie; Godskesen, Berit; Rygaard, Martin

    2015-01-01

    used in this study: the Withdrawal-To-Availability ratio (WTA) and the Water Stress Index (WSI). Results were calculated for three groundwater based Danish urban water supplies (Esbjerg, Aarhus, and Copenhagen). The assessment was carried out at three spatial levels: (1) the groundwater body level, (2......) the river basin level, and (3) the regional level. The assessments showed that Copenhagen's water supply had the highest impact on the freshwater resource per cubic meter of water abstracted, with a WSI of 1.75 at Level 1. The WSI values were 1.64 for Aarhus's and 0.81 for Esbjerg's water supply. Spatial......Indicators of the impact on freshwater resources are becoming increasingly important in the evaluation of urban water systems. To reveal the importance of spatial resolution, we investigated how the choice of catchment scale influenced the freshwater impact assessment. Two different indicators were...

  4. A Potential Approach for Low Flow Selection in Water Resource Supply and Management

    Science.gov (United States)

    Ying Ouyang

    2012-01-01

    Low flow selections are essential to water resource management, water supply planning, and watershed ecosystem restoration. In this study, a new approach, namely the frequent-low (FL) approach (or frequent-low index), was developed based on the minimum frequent-low flow or level used in minimum flows and/or levels program in northeast Florida, USA. This FL approach was...

  5. Analysis of selected elements in water in the drinking water preparation plants in Belgrade, Serbia

    Directory of Open Access Journals (Sweden)

    Antanasijević Davor Z.

    2011-01-01

    Full Text Available Belgrade's water supply relies mainly on the River Sava and groundwater supply wells, which are located in the vicinity of the river and Ada Ciganlija. In this paper, the content of aluminum, boron, chromium, manganese, cobalt, nickel, copper, zinc, arsenic, cadmium, barium and lead was analyzed in raw water as well as drinking water distributed by the Water Supply and Sewage of Belgrade. A total of 14 samples were examined from all water treatment plants that are part of the distribution system. The measurements were conducted using the inductively coupled plasma-mass spectrometry (ICP-MS technique. The aim of this research was to examine the effectiveness of drinking water preparation process in the plants belonging to the Water Supply and Sewage of Belgrade. The content of certain elements varies considerably in raw water (river and groundwater: the concentration of boron in river water is two to three times lower than the concentration in groundwater; the concentration of arsenic in river water is ten to twenty five times lower than the concentration in groundwater; the concentration of aluminum in all groundwater samples was below the detection limit of the instrument (0.50 μg/dm3, whilst in the river water the content of aluminum was about 50 μg/dm3 and the concentration of manganese in the river water was up to 10 times lower than the concentrations in groundwater. In all drinking water samples the concentration of the elements were bellow the maximum allowed levels according to the Serbian regulations. Correlation coefficients determined for boron, manganese, cobalt, nickel, copper, zinc, arsenic, barium and lead, which were analyzed in raw waters, show that four groups of elements can be distinguished. Boron, manganese, arsenic and barium are related to each other and probably have a common natural origin; copper and lead probably have a common anthropogenic origin; correlation of nickel and cobalt was observed, while zinc was not in

  6. Water stress drastically reduces root growth and inulin yield in Cichorium intybus (var. sativum) independently of photosynthesis

    Science.gov (United States)

    Vandoorne, B.; Mathieu, A.-S.; Van den Ende, W.; Vergauwen, R.; Périlleux, C.; Javaux, M.; Lutts, S.

    2012-01-01

    Root chicory (Cichorium intybus var. sativum) is a cash crop cultivated for inulin production in Western Europe. This plant can be exposed to severe water stress during the last 3 months of its 6-month growing period. The aim of this study was to quantify the effect of a progressive decline in water availability on plant growth, photosynthesis, and sugar metabolism and to determine its impact on inulin production. Water stress drastically decreased fresh and dry root weight, leaf number, total leaf area, and stomatal conductance. Stressed plants, however, increased their water-use efficiency and leaf soluble sugar concentration, decreased the shoot-to-root ratio and lowered their osmotic potential. Despite a decrease in photosynthetic pigments, the photosynthesis light phase remained unaffected under water stress. Water stress increased sucrose phosphate synthase activity in the leaves but not in the roots. Water stress inhibited sucrose:sucrose 1-fructosyltransferase and fructan:fructan 1 fructosyltransferase after 19 weeks of culture and slightly increased fructan 1-exohydrolase activity. The root inulin concentration, expressed on a dry-weight basis, and the mean degree of polymerization of the inulin chain remained unaffected by water stress. Root chicory displayed resistance to water stress, but that resistance was obtained at the expense of growth, which in turn led to a significant decrease in inulin production. PMID:22577185

  7. Modeling of primary water stress corrosion cracking at control rod drive mechanism nozzles of pressurized water reactors

    International Nuclear Information System (INIS)

    Aly, Omar Fernandes

    2006-01-01

    One of the main failure mechanisms that cause risks to pressurized water reactors is the primary water stress corrosion cracking (PWSCC) occurring in alloys. It can occurs, besides another places, at the control reactor displacement mechanism nozzles. It is caused by the joint effect of tensile stress, temperature, susceptible metallurgical microstructure and environmental conditions of the primary water. These cracks can cause accidents that reduce nuclear safety by blocking the rod's displacement and may cause leakage of primary water, reducing the reactor's life. In this work it is proposed a study of the existing models and a modeling proposal to primary water stress corrosion cracking in these nozzles in a nickel based Alloy 600. It is been superposed electrochemical and fracture mechanics models, and validated using experimental and literature data. The experimental data were obtained at CDTN-Brazilian Nuclear Technology Development Center, in a recent installed slow strain rate testing equipment. In the literature it is found a diagram that indicates a thermodynamic condition for the occurrence of some PWSCC sub modes in Alloy 600: it was used potential x pH diagrams (Pourbaix diagrams), for Alloy 600 in high temperature primary water (300 deg C till 350 deg C). Over it, were located the PWSCC sub modes, using experimental data. It was added a third parameter called 'stress corrosion strength fraction'. However, it is possible to superpose to this diagram, other parameters expressing PWSCC initiation or growth kinetics from other models. Here is the proposition of the original contribution of this work: from an original experimental condition of potential versus pH, it was superposed, an empiric-comparative, a semi-empiric-probabilistic, an initiation time, and a strain rate damage models, to quantify respectively the PWSCC susceptibility, the failure time, and in the two lasts, the initiation time of stress corrosion cracking. It was modeling from our

  8. Effect on Quality Characteristics of Tomatoes Grown Under Well-Watered and Drought Stress Conditions.

    Science.gov (United States)

    Klunklin, Warinporn; Savage, Geoffrey

    2017-07-25

    Tomatoes are one of the most nutritionally and economically important crops in New Zealand and around the world. Tomatoes require large amounts of water to grow well and are adversely affected by drought stress. However, few studies have evaluated the physicochemical characteristics of commercial tomatoes grown under water stress conditions. Four tomato cultivars (Incas, Marmande, Scoresby Dwarf, and Window Box Red) were grown in a greenhouse under well-watered and drought stress conditions and the tomatoes were harvested when ripe. The physicochemical properties and antioxidant contents of the fruits were compared. There were significant differences between cultivars in quality characteristics-such as dry matter, total soluble solids, and pH parameters-but there were no differences in the quality characteristics between the two treatments of the fruits ( p > 0.05); however, there were significant differences ( p < 0.05) in the antioxidant compositions (lycopene, total phenolics, and flavonoids) and antioxidant activities (DPPH and ABTS) of the fruits of both cultivars and treatments. Overall, these results indicated that tomatoes increased their bioactive compounds without changing any quality characteristics when exposed to water stress conditions.

  9. Combined effects of water, nutrient, and UV-B stress on female fitness in Brassica (Brassicaceae)

    International Nuclear Information System (INIS)

    Conner, J.K.; Zangori, L.A.

    1998-01-01

    Our knowledge of the effects of increased levels of ultraviolet-B radiation (UV-B) on plant fitness is limited mainly to yield studies in a few crop species. Previous greenhouse and garden studies of Brassica have found greater detrimental effects of UV-B on fitness in gardens than in the greenhouse, suggesting the possibility that additional stresses in the field decrease the ability of Brassica to cope with UV-B. Possible interactions between UV-B and water/nutrient stress in determining plant fitness have rarely, if ever, been studied experimentally. Here we report measurements of female fitness in two species of Brassica in an experiment in which both UV-B and levels of water and nutrients were varied in a 2 X 2 factorial design. Water and nutrient stress reduced female fitness in both species, while UV-B caused fitness reductions in only one of the species. There was evidence for interactions between UV-B and water/nutrient stress for only a few of the traits measured; most traits, including those closely related to fitness, showed no evidence of an interaction

  10. Magnetic resonance imaging of plants: plant water status and drought stress response

    NARCIS (Netherlands)

    Weerd-Meulenkamp, van der L.

    2002-01-01

    This Thesis presents an approach for the study of plant water balance during drought stress, using a combination of in vivo NMR experiments and computer simulations. The ultimate aim is the interpretation of the NMR parameters in terms of physiologically relevant characteristics, such as

  11. Leaf water stress detection utilizing thematic mapper bands 3, 4 and 5 in soybean plants

    Science.gov (United States)

    Holben, B. N.; Schutt, J. B.; Mcmurtrey, J., III

    1983-01-01

    The total and diffuse radiance responses of Thematic Mapper bands 3 (0.63-0.69 microns), 4 (0.76-0.90 microns), and 5 (1.55-1.75 microns) to water stress in a soybean canopy are compared. Polarization measurements were used to separate the total from the diffuse reflectance; the reflectances were compared statistically at a variety of look angles at 15 min intervals from about 09.00 until 14.00 hrs EST. The results suggest that remotely sensed data collected in the photographic infrared region (TM4) are sensitive to leaf water stress in a 100 percent canopy cover of soybeans, and that TM3 is less sensitive than TM4 for detection of reversible foliar water stress. The mean values of TM5 reflectance data show similar trends to TM4. The primary implication of this study is that remote sensing of water stress in green plant canopies is possible in TM4 from ground-based observations primarily through the indirect link of leaf geometry.

  12. Infrared thermometry of water-stressed crops - emerging methods and technologies

    Science.gov (United States)

    Infrared thermometry has shown potential to quantify water stress in crop canopy. This presentation will outline the limited irrigation experiments by the USDA-ARS in northern Colorado, which is used for a framework to evaluate canopy temperature. Recent methods have been introduced that may be accu...

  13. Long-term application of the Crop Water Stress Index in Midwest agro-ecosystems

    Science.gov (United States)

    Agricultural land in the Midwestern US is largely used for rainfed corn (Zea mays L.) and soybean (Glycine max (L.) Merr.) production. The native ecosystems in this region predominantly consist of tallgrass prairie. Water stress can occur in summer which can affect carbon assimilation of those agro-...

  14. Development of an irrigation scheduling software based on model predicted crop water stress

    Science.gov (United States)

    Modern irrigation scheduling methods are generally based on sensor-monitored soil moisture regimes rather than crop water stress which is difficult to measure in real-time, but can be computed using agricultural system models. In this study, an irrigation scheduling software based on RZWQM2 model pr...

  15. Water-Stressed Loquat Trees Need More Time and Heat to Ripen Their Fruits

    Directory of Open Access Journals (Sweden)

    Julián Cuevas

    2018-06-01

    Full Text Available To determine if water-stressed trees need more time and heat to mature their fruits, we compared chronological and thermal time from bloom to harvest among control fully-irrigated ‘Algerie’ loquat trees and trees suffering prior-to-bloom deficit irrigation (DI. Heat requirement calculation was performed using the double sine method with a lower threshold temperature of 3 °C. The results show that the greater the blooming advancement achieved by DI, the longer the period to mature the fruits. Such a pattern indicates that the longer duration for bloom-harvest period under DI is due to a displacement of the reproductive phenology to cooler dates. However, some effects of DI on heat requirements for ripening persist, indicating a slower fruit development in some, but not all, DI treatments. The differences in fruit development rate between fully-irrigated and water-stressed trees were established during the phase of rapid fruit growth. The comparison of water stress effects on sink (flower size and seed number and source (leaf number and size, gas exchange and mineral and carbohydrate nutrition of DI treatments seems to indicate that the amount of stored reserves in the leaves to sustain early fruit development is the most plausible reason behind the increase in thermal time between bloom and harvest in water-stressed loquats.

  16. Bridging effective stress and soil water retention equations in deforming unsaturated porous media : A Thermodynamic Approach

    NARCIS (Netherlands)

    Huyghe, J. M.; Nikooee, E.; Hassanizadeh, S. M.

    The finite deformation of an unsaturated porous medium is analysed from first principles of mixture theory. An expression for Bishop’s effective stress is derived from (1) the deformation-dependent Brooks and Corey’s water retention curve and (2) the restrictions on the constitutive relationships of

  17. 14C-incorporation into sugars and organic acids of water-stressed maize leaves

    International Nuclear Information System (INIS)

    Becker, T.; Fock, H.

    1986-01-01

    The incorporation of 14 C into sugars and some organic acids of maize leaves has been studied in relation to the leaf water potential by feeding 14 CO 2 (370 ppm) for 1,2 and 4 min during steady state photosynthesis at 25 0 C (PAR = 800 μmol m -2 s -1 ). The relative specific radioactivity (RSA) of the sugars was low (0.2% after 4 min) at -0.62 MPa (control) and decreased by about 50% when psi dropped to -0.95 MPa. The authors conclude that the low rate of photosynthetic sugar synthesis in maize leaves decreased during water stress. The RSA of malate was extremely low at -0.62 MPa (0.02%). This result may be the consequence of the large pool size of malate in maize leaves. The authors presume that there are two malate pools present in maize leaves, a small metabolic pool and a larger storage pool. The RSA of malate decreased during the stress period. This is consistent with the decline in net CO 2 uptake during water stress. The pool sizes of citrate and isocitrate increased when psi dropped to -0.95 MPa. As practically no radioactivity was detected in these organic acids, they conclude that these compounds are synthesized from unlabelled precursors during water stress

  18. Effect of mineral nitrogen fertilization on growth characteristics of lucerne under induced water deficiency stress

    International Nuclear Information System (INIS)

    Vasileva, V.; Vasilev, E.; Athar, M.

    2011-01-01

    Utility of lucerne crop fertilization with nitrogen fertilizer has been discussed in literature with controversy. In this study experiment was conducted to determine the effect of mineral nitrogen at the doses of 40, 80, 120 and 160 mg N/kg on some characteristics of lucerne under induced water deficiency stress at the stage of budding in a pot trial. It was found that mineral nitrogen at the doses of 120 and 160 mg N/kg soil increased the productivity of dry top mass by 17 and 23% in conditions of optimum moisture, and by 9% in conditions of water deficiency stress at the dose of 80 mg N/kg soil. Application of mineral nitrogen at the dose of 120 and 160 mg N/kg soil increased the quantity of dry root mass by 43 and 38% for the conditions of optimum moisture, and by 54-56% for conditions of water deficiency stress. Mineral nitrogen fertilizing at the dose of 40 mg N/kg soil had the lowest suppressive effect on the nodulation (11%). The dose of 160 mg N/kg soil was found to be toxic to nodulation. The dose of 80 mg N/kg soil, at which the crop had the lowest sensitivity to water deficiency stress, was optimal for lucerne development. (author)

  19. Effect of water stress on yield and yield components of sunflower ...

    African Journals Online (AJOL)

    A field experiment during year 2009 was conducted in the research station of the University of Tehran, College of Abouraihan in Pakdasht region, Iran. The study was aimed to investigate the effect of water stress on seed yield, yield component and some quantitative traits of four sunflower hybrids namely Azargol, Alstar, ...

  20. Interactions between abscisic acid and cytokinins during water stress and subsequent rehydration

    Czech Academy of Sciences Publication Activity Database

    Pospíšilová, Jana; Vágner, Martin; Malbeck, Jiří; Trávníčková, Alena; Baťková, Petra

    2005-01-01

    Roč. 49, - (2005), s. 533-540 ISSN 0006-3134 R&D Projects: GA ČR GA522/02/1099; GA AV ČR(CZ) IAA638105 Institutional research plan: CEZ:AV0Z50380511 Keywords : abscisic acid * cytokinins * water stress Subject RIV: EF - Botanics Impact factor: 0.792, year: 2005

  1. Effect of soil water stress on yield and proline content of four wheat ...

    African Journals Online (AJOL)

    STORAGESEVER

    2010-01-04

    Jan 4, 2010 ... Four lines of bread wheat (N-82-9, N-83-5, ... Key words: Water stress, Triticum aestivum, yield, proline, TSS. .... Numbers in the columns followed by the same letters are not significantly different at P .... constituents, Acta Bot.

  2. Oxidative stress induced on Cyprinus carpio by contaminants present in the water and sediment of Madin Reservoir.

    Science.gov (United States)

    Galar-Martinez, Marcela; Gomez-Olivan, Leobardo Manuel; Amaya-Chavez, Araceli; Razo-Estrada, Celene; Garcia-Medina, Sandra

    2010-01-01

    Madin Reservoir (MR), located in the State of Mexico, is fed mainly by the Rio Tlalnepantla. MR supplies potable water to the municipalities of Naucalpan and Atizapan, and various recreational activities take place in its vicinity, such as sailing and the fishing of diverse species including the common carp Cyprinus carpio. The purpose of this study was to determine the toxic effects of contaminants present in MR water and sediment on C. carpio. Five sampling stations were selected (those considered to have the most problems due to discharges). Water and sediment samples were taken and toxicity studies were performed, including acute toxicity (lethality) and subacute toxicity assays. The biomarkers used in the subacute assays were lipid peroxidation (LPX) and activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) in the liver and brain of test organisms. These biomarkers were also evaluated in local carp, i.e. carp with chronic exposure in situ to reservoir contaminants. Results show that contaminants in the water and sediment of the different sampling stations induce oxidative stress, this toxicity being more evident in samples from stations near the entry point of the Rio Tlalnepantla tributary and in local carp. This may be due to high contaminant levels as well as the fact that the physicochemical characteristics of the matrices might favor their bioavailability. Thus, both the water and sediment of this reservoir are contaminated with xenobiotics hazardous to C. carpio, a species consumed by the local human population.

  3. Selective downregulation of mitochondrial electron transport chain activity and increased oxidative stress in human atrial fibrillation.

    Science.gov (United States)

    Emelyanova, Larisa; Ashary, Zain; Cosic, Milanka; Negmadjanov, Ulugbek; Ross, Gracious; Rizvi, Farhan; Olet, Susan; Kress, David; Sra, Jasbir; Tajik, A Jamil; Holmuhamedov, Ekhson L; Shi, Yang; Jahangir, Arshad

    2016-07-01

    Mitochondria are critical for maintaining normal cardiac function, and a deficit in mitochondrial energetics can lead to the development of the substrate that promotes atrial fibrillation (AF) and its progression. However, the link between mitochondrial dysfunction and AF in humans is still not fully defined. The aim of this study was to elucidate differences in the functional activity of mitochondrial oxidative phosphorylation (OXPHOS) complexes and oxidative stress in right atrial tissue from patients without (non-AF) and with AF (AF) who were undergoing open-heart surgery and were not significantly different for age, sex, major comorbidities, and medications. The overall functional activity of the electron transport chain (ETC), NADH:O2 oxidoreductase activity, was reduced by 30% in atrial tissue from AF compared with non-AF patients. This was predominantly due to a selective reduction in complex I (0.06 ± 0.007 vs. 0.09 ± 0.006 nmol·min(-1)·citrate synthase activity(-1), P = 0.02) and II (0.11 ± 0.012 vs. 0.16 ± 0.012 nmol·min(-1)·citrate synthase activity(-1), P = 0.003) functional activity in AF patients. Conversely, complex V activity was significantly increased in AF patients (0.21 ± 0.027 vs. 0.12 ± 0.01 nmol·min(-1)·citrate synthase activity(-1), P = 0.005). In addition, AF patients exhibited a higher oxidative stress with increased production of mitochondrial superoxide (73 ± 17 vs. 11 ± 2 arbitrary units, P = 0.03) and 4-hydroxynonenal level (77.64 ± 30.2 vs. 9.83 ± 2.83 ng·mg(-1) protein, P = 0.048). Our findings suggest that AF is associated with selective downregulation of ETC activity and increased oxidative stress that can contribute to the progression of the substrate for AF. Copyright © 2016 the American Physiological Society.

  4. Genomic selection for tolerance to heat stress in Australian dairy cattle.

    Science.gov (United States)

    Nguyen, Thuy T T; Bowman, Phil J; Haile-Mariam, Mekonnen; Pryce, Jennie E; Hayes, Benjamin J

    2016-04-01

    Temperature and humidity levels above a certain threshold decrease milk production in dairy cattle, and genetic variation is associated with the amount of lost production. To enable selection for improved heat tolerance, the aim of this study was to develop genomic estimated breeding values (GEBV) for heat tolerance in dairy cattle. Heat tolerance was defined as the rate of decline in production under heat stress. We combined herd test-day recording data from 366,835 Holstein and 76,852 Jersey cows with daily temperature and humidity measurements from weather stations closest to the tested herds for test days between 2003 and 2013. We used daily mean values of temperature-humidity index averaged for the day of test and the 4 previous days as the measure of heat stress. Tolerance to heat stress was estimated for each cow using a random regression model with a common threshold of temperature-humidity index=60 for all cows. The slope solutions for cows from this model were used to define the daughter trait deviations of their sires. Genomic best linear unbiased prediction was used to calculate GEBV for heat tolerance for milk, fat, and protein yield. Two reference populations were used, the first consisted of genotyped sires only (2,300 Holstein and 575 Jersey sires), and the other included genotyped sires and cows (2,189 Holstein and 1,188 Jersey cows). The remainder of the genotyped sires were used as a validation set. All animals had genotypes for 632,003 single nucleotide polymorphisms. When using only genotyped sires in the reference set and only the first parity data, the accuracy of GEBV for heat tolerance in relation to changes in milk, fat, and protein yield were 0.48, 0.50, and 0.49 in the Holstein validation sires and 0.44, 0.61, and 0.53 in the Jersey validation sires, respectively. Some slight improvement in the accuracy of prediction was achieved when cows were included in the reference population for Holsteins. No clear improvements in the accuracy of

  5. Water stress as a trigger of demand change: exploring the implications for drought planning

    Science.gov (United States)

    Garcia, M. E.; Islam, S.; Portney, K. E.

    2015-12-01

    Drought in the Anthropocene is a function of both supply and demand. Despite its importance, demand is typically incorporated into planning models exogenously using a single scenario of demand change over time. Alternatively, demand is incorporated endogenously in hydro-economic models based on the assumption of rationality. However, actors are constrained by limited information and information processing capabilities, casting doubt on the rationality assumption. Though the risk of water shortage changes incrementally with demand growth and hydrologic change, significant shifts in management are punctuated and often linked to periods of stress. The observation of lasting decreases in per capita demands in a number of cities during periods of water stress prompts an alternate hypothesis: the occurrence of water stress increases the tendency of cities to promote and enforce efficient technologies and behaviors and the tendency of users to adopt them. We show the relevance of this hypothesis by building a model of a hypothetical surface water system to answer the following question: what is the impact of reservoir operation policy on the reliability of water supply for a growing city? The model links the rate of demand decreases to the past reliability to compare standard operating policy (SOP) with hedging policy (HP). Under SOP, demand is fulfilled unless available supply drops below demand; under HP, water releases are reduced in anticipation of a deficit to decrease the risk of a large shortfall. The model shows that reservoir storage acts both as a buffer for variability and as a delay triggering oscillations around a sustainable level of demand. HP reduces the threshold for action thereby decreasing the delay and the oscillation effect. As a result per capita demand decrease during periods of water stress are more frequent but less drastic and the additive effect of small adjustments decreases the tendency of the system to overshoot available supplies.

  6. Rainfall and crop modeling-based water stress assessment for rainfed maize cultivation in peninsular India

    Science.gov (United States)

    Manivasagam, V. S.; Nagarajan, R.

    2018-04-01

    Water stress due to uneven rainfall distribution causes a significant impact on the agricultural production of monsoon-dependent peninsular India. In the present study, water stress assessment for rainfed maize crop is carried out for kharif (June-October) and rabi (October-February) cropping seasons which coincide with two major Indian monsoons. Rainfall analysis (1976-2010) shows that the kharif season receives sufficient weekly rainfall (28 ± 32 mm) during 26th-39th standard meteorological weeks (SMWs) from southwest monsoon, whereas the rabi season experiences a major portion of its weekly rainfall due to northeast monsoon between the 42nd and 51st SMW (31 ± 42 mm). The later weeks experience minimal rainfall (5.5 ± 15 mm) and thus expose the late sown maize crops to a severe water stress during its maturity stage. Wet and dry spell analyses reveal a substantial increase in the rainfall intensity over the last few decades. However, the distribution of rainfall shows a striking decrease in the number of wet spells, with prolonged dry spells in both seasons. Weekly rainfall classification shows that the flowering and maturity stages of kharif maize (33rd-39th SMWs) can suffer around 30-40% of the total water stress. In the case of rabi maize, the analysis reveals that a shift in the sowing time from the existing 42nd SMW (16-22 October) to the 40th SMW (1-7 October) can avoid terminal water stress. Further, AquaCrop modeling results show that one or two minimal irrigations during the flowering and maturity stages (33rd-39th SMWs) of kharif maize positively avoid the mild water stress exposure. Similarly, rabi maize requires an additional two or three lifesaving irrigations during its flowering and maturity stages (48th-53rd SMWs) to improve productivity. Effective crop planning with appropriate sowing time, short duration crop, and high yielding drought-resistant varieties will allow for better utilization of the monsoon rain, thus reducing water stress with

  7. Experimental determination of residual stress by neutron diffraction in a boiling water reactor core shroud

    International Nuclear Information System (INIS)

    Payzant, A.; Spooner, S.; Zhu, Xiaojing; Hubbard, C.R.

    1996-01-01

    Residual strains in a 51 mm (2-inch) thick 304L stainless steel plate have been measured by neutron diffraction and interpreted in terms of residual stress. The plate, measuring (300 mm) in area, was removed from a 6m (20-ft.) diameter unirradiated boiling water reactor core shroud, and included a multiple-pass horizontal weld which joined two of the cylindrical shells which comprise the core shroud. Residual stress mapping was undertaken in the heat affected zone, concentrating on the outside half of the plate thickness. Variations in residual stresses with location appeared consistent with trends expected from finite element calculations, considering that a large fraction of the residual hoop stress was released upon removal of the plate from the core shroud cylinder

  8. Selection for increased desiccation resistance in Drosophila melanogaster: Additive genetic control and correlated responses for other stresses

    International Nuclear Information System (INIS)

    Hoffmann, A.A.; Parsons, P.A.

    1989-01-01

    Previously we found that Drosophila melanogaster lines selected for increased desiccation resistance have lowered metabolic rate and behavioral activity levels, and show correlated responses for resistance to starvation and a toxic ethanol level. These results were consistent with a prediction that increased resistance to many environmental stresses may be genetically correlated because of a reduction in metabolic energy expenditure. Here we present experiments on the genetic basis of the selection response and extend the study of correlated responses to other stresses. The response to selection was not sex-specific and involved X-linked and autosomal genes acting additively. Activity differences contributed little to differences in desiccation resistance between selected and control lines. Selected lines had lower metabolic rates than controls in darkness when activity was inhibited. Adults from selected lines showed increased resistance to a heat shock, 60 Co-gamma-radiation, and acute ethanol and acetic acid stress. The desiccation, ethanol and starvation resistance of isofemale lines set up from the F2s of a cross between one of the selected and one of the control lines were correlated. Selected and control lines did not differ in ether-extractable lipid content or in resistance to acetone, ether or a cold shock

  9. Establishing and testing a catchment water footprint framework to inform sustainable irrigation water use for an aquifer under stress.

    Science.gov (United States)

    le Roux, Betsie; van der Laan, Michael; Vahrmeijer, Teunis; Bristow, Keith L; Annandale, John G

    2017-12-01

    Future water scarcities in the face of an increasing population, climate change and the unsustainable use of aquifers will present major challenges to global food production. The ability of water footprints (WFs) to inform water resource management at catchment-scale was investigated on the Steenkoppies Aquifer, South Africa. Yields based on cropping areas were multiplied with season-specific WFs for each crop to determine blue and green water consumption by agriculture. Precipitation and evapotranspiration of natural vegetation and other uses of blue water were included with the agricultural WFs to compare water availability and consumption in a catchment sustainability assessment. This information was used to derive a water balance and develop a catchment WF framework that gave important insights into the hydrology of the aquifer through a simplified method. This method, which requires the monitoring of only a few key variables, including rainfall, agricultural production, WFs of natural vegetation and other blue water flows, can be applied to inform the sustainability of catchment scale water use (as opposed to more complex hydrological studies). Results indicate that current irrigation on the Steenkoppies Aquifer is unsustainable. This is confirmed by declining groundwater levels, and suggests that there should be no further expansion of irrigated agriculture on the Steenkoppies Aquifer. Discrepancies between in- and outflows of water in the catchment indicated that further development of the WF approach is required to improve understanding of the geohydrology of the aquifer and to set and meet sustainability targets for the aquifer. It is envisaged that this 'working' framework can be applied to other water-stressed aquifers around the world. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  10. Effects of ultraviolet-B radiation on plants during mild water stress, 4: The insensitivity of soybean internal water relations to ultraviolet-B radiation

    International Nuclear Information System (INIS)

    Teramura, A.H.; Forseth, I.N.; Lydon, J.

    1984-01-01

    The combined effects of ultraviolet-B (UV-B, 280–320 nm) radiation and water stress were investigated on the water relations of greenhouse grown soybean [Glycine max (L.) Merr. cv. Essex]. On a weighted (Caldwell 1971), total daily dose basis, plants received either 0 or 3 000 effective J m 2 UV-B BE supplied by filtered FS-40 sunlamps. The latter dose simulated the solar UV-B radiation anticipated at College Park, Maryland, U.S.A. (39°N latitude) in the event that the global stratospheric ozone column is reduced by 25%. Plants were either well-watered or preconditioned by drought stress cycles. Diurnal measurements of water potential and stomatal conductance were made on the youngest fully expanded leaf. Various internal water relations parameters were determined for detached leaves. Plants were monitored before, during and after water stress. There were no significant differences in leaf water potential or stomatal conductance between treatments before plants were preconditioned to water stress. However, drought stress resulted in significantly lower midday and afternoon leaf water potentials and lower leaf conductances as compared to well-watered plants. UV-B radiation had no additional effect on leaf water potential; however, UV did result in lower leaf conductances in plants preconditioned to water stress. Turgid weight:dry weight ratio, elastic modulus, bound water and relative water content were unaffected by UV-B radiation. Osmotic potentials at full and zero turgor were significantly lower in the drought stressed treatments as compared to well-watered plants. (author)

  11. Violaxanthin is an abscisic acid precursor in water-stressed dark-grown bean leaves

    International Nuclear Information System (INIS)

    Li, Yi; Walton, D.C.

    1990-01-01

    The leaves a dark-grown bean (Phaseolus vulgaris L.) seedlings accumulate considerably lower quantities of xanthophylls and carotenes than do leaves of light-grown seedlings, but they synthesize at least comparable amounts of abscisic acid (ABA) and its metabolites when water stressed. We observed a 1:1 relationship on a molar basis between the reduction in levels of ciolaxanthin, 9'-cis-neoxanthin, and 9-cis-violaxanthin and the accumulation of ABA, phaseic acid, and dihydrophaseic acid, when leaves from dark-grown plants were stressed for 7 hours. Early in the stress period, reductions in xanthophylls were greater than the accumulation of ABA and its metabolites, suggesting the accumulation of an intermediate which was subsequently converted to ABA. Leaves which were detached, but no stressed, did not accumulate ABA nor were their xanthophyll levels reduced. Leaves from plants that had been sprayed with cycloheximido did not accumulate ABA when stressed, nor were their xanthophyll levels reduced significantly. Incubation of dark-grown stressed leaves in an 18 O 2 -containing atmosphere resulted in the synthesis of ABA with levels of 18 O in the carboxyl group that were virtually identical to those observed in light-grown leaves. The results of these experiments indicate that violaxanthin is an ABA precursor in stressed dark-grown leaves, and they are used to suggest several possible pathways from violaxanthin to ABA

  12. Regulation of water, salinity, and cold stress responses by salicylic acid

    Directory of Open Access Journals (Sweden)

    Kenji eMiura

    2014-01-01

    Full Text Available Salicylic acid (SA is a naturally occurring phenolic compound. SA plays an important role in the regulation of plant growth, development, ripening, and defense responses. The role of SA in the plant-pathogen relationship has been extensively investigated. In addition to defense responses, SA plays an important role in the response to abiotic stresses, including drought, low temperature, and salinity stresses. It has been suggested that SA has great agronomic potential to improve the stress tolerance of agriculturally important crops. However, the utility of SA is dependent on the concentration of the applied SA, the mode of application, and the state of the plants (e.g., developmental stage and acclimation. Generally, low concentrations of applied SA alleviate the sensitivity to abiotic stresses, and high concentrations of applied induce high levels of oxidative stress, leading to a decreased tolerance to abiotic stresses. In this chapter, the effects of SA on the water stress responses and regulation of stomatal closure are reviewed.

  13. Violaxanthin is an abscisic acid precursor in water-stressed dark-grown bean leaves

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yi; Walton, D.C. (State Univ. of New York, Syracuse (USA))

    1990-03-01

    The leaves a dark-grown bean (Phaseolus vulgaris L.) seedlings accumulate considerably lower quantities of xanthophylls and carotenes than do leaves of light-grown seedlings, but they synthesize at least comparable amounts of abscisic acid (ABA) and its metabolites when water stressed. We observed a 1:1 relationship on a molar basis between the reduction in levels of ciolaxanthin, 9{prime}-cis-neoxanthin, and 9-cis-violaxanthin and the accumulation of ABA, phaseic acid, and dihydrophaseic acid, when leaves from dark-grown plants were stressed for 7 hours. Early in the stress period, reductions in xanthophylls were greater than the accumulation of ABA and its metabolites, suggesting the accumulation of an intermediate which was subsequently converted to ABA. Leaves which were detached, but no stressed, did not accumulate ABA nor were their xanthophyll levels reduced. Leaves from plants that had been sprayed with cycloheximido did not accumulate ABA when stressed, nor were their xanthophyll levels reduced significantly. Incubation of dark-grown stressed leaves in an {sup 18}O{sub 2}-containing atmosphere resulted in the synthesis of ABA with levels of {sup 18}O in the carboxyl group that were virtually identical to those observed in light-grown leaves. The results of these experiments indicate that violaxanthin is an ABA precursor in stressed dark-grown leaves, and they are used to suggest several possible pathways from violaxanthin to ABA.

  14. Influence of Transformation Plasticity on the Distribution of Internal Stress in Three Water-Quenched Cylinders

    Science.gov (United States)

    Liu, Yu; Qin, Shengwei; Zhang, Jiazhi; Wang, Ying; Rong, Yonghua; Zuo, Xunwei; Chen, Nailu

    2017-10-01

    Based on the hardenability of three medium carbon steels, cylinders with the same 60-mm diameter and 240-mm length were designed for quenching in water to obtain microstructures, including a pearlite matrix (Chinese steel mark: 45), a bainite matrix (42CrMo), and a martensite matrix (40CrNiMo). Through the combination of normalized functions describing transformation plasticity (TP), the thermo-elasto-plastic constitutive equation was deduced. The results indicate that the finite element simulation (FES) of the internal stress distribution in the three kinds of hardenable steel cylinders based on the proposed exponent-modified (Ex-Modified) normalized function is more consistent with the X-ray diffraction (XRD) measurements than those based on the normalized functions proposed by Abrassart, Desalos, and Leblond, which is attributed to the fact that the Ex-Modified normalized function better describes the TP kinetics. In addition, there was no significant difference between the calculated and measured stress distributions, even though TP was taken into account for the 45 carbon steel; that is, TP can be ignored in FES. In contrast, in the 42CrMo and 40CrNiMo alloyed steels, the significant effect of TP on the residual stress distributions was demonstrated, meaning that TP must be included in the FES. The rationality of the preceding conclusions was analyzed. The complex quenching stress is a consequence of interactions between the thermal and phase transformation stresses. The separated calculations indicate that the three steels exhibit similar thermal stress distributions for the same water-quenching condition, but different phase transformation stresses between 45 carbon steel and alloyed steels, leading to different distributions of their axial and tangential stresses.

  15. Nodule activity and allocation of photosynthate of soybean during recovery from water stress

    Science.gov (United States)

    Fellows, R. J.; Patterson, R. P.; Raper, C. D. Jr; Harris, D.; Raper CD, J. r. (Principal Investigator)

    1987-01-01

    Nodulated soybean plants (Glycine max [L.] Merr. cv Ransom) in a growth-chamber study were subjected to a leaf water potential (psi w) of -2.0 megapascal during vegetative growth. Changes in nonstructural carbohydrate contents of leaves, stems, roots, and nodules, allocation of dry matter among plant parts, in situ specific nodule activity, and in situ canopy apparent photosynthetic rate were measured in stressed and nonstressed plants during a 7-day period following rewatering. Leaf and nodule psi w also were determined. At the time of maximum stress, concentration of nonstructural carbohydrates had declined in leaves of stressed, relative to nonstressed, plants, and the concentration of nonstructural carbohydrates had increased in stems, roots, and nodules. Sucrose concentrations in roots and nodules of stressed plants were 1.5 and 3 times greater, respectively, than those of nonstressed plants. Within 12 hours after rewatering, leaf and nodule psi w of stressed plants had returned to values of nonstressed plants. Canopy apparent photosynthesis and specific nodule activity of stressed plants recovered to levels for nonstressed plants within 2 days after rewatering. The elevated sucrose concentrations in roots and nodules of stressed plants also declined rapidly upon rehydration. The increase in sucrose concentration in nodules, as well as the increase of carbohydrates in roots and stems, during water stress and the rapid disappearance upon rewatering indicates that inhibition of carbohydrate utilization within the nodule may be associated with loss of nodule activity. Availability of carbohydrates within the nodules and from photosynthetic activity following rehydration of nodules may mediate the rate of recovery of N2-fixation activity.

  16. Selection of Reference Genes for qRT-PCR Analysis of Gene Expression in Stipa grandis during Environmental Stresses.

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    Dongli Wan

    Full Text Available Stipa grandis P. Smirn. is a dominant plant species in the typical steppe of the Xilingole Plateau of Inner Mongolia. Selection of suitable reference genes for the quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR is important for gene expression analysis and research into the molecular mechanisms underlying the stress responses of S. grandis. In the present study, 15 candidate reference genes (EF1 beta, ACT, GAPDH, SamDC, CUL4, CAP, SNF2, SKIP1, SKIP5, SKIP11, UBC2, UBC15, UBC17, UCH, and HERC2 were evaluated for their stability as potential reference genes for qRT-PCR under different stresses. Four algorithms were used: GeNorm, NormFinder, BestKeeper, and RefFinder. The results showed that the most stable reference genes were different under different stress conditions: EF1beta and UBC15 during drought and salt stresses; ACT and GAPDH under heat stress; SKIP5 and UBC17 under cold stress; UBC15 and HERC2 under high pH stress; UBC2 and UBC15 under wounding stress; EF1beta and UBC17 under jasmonic acid treatment; UBC15 and CUL4 under abscisic acid treatment; and HERC2 and UBC17 under salicylic acid treatment. EF1beta and HERC2 were the most suitable genes for the global analysis of all samples. Furthermore, six target genes, SgPOD, SgPAL, SgLEA, SgLOX, SgHSP90 and SgPR1, were selected to validate the most and least stable reference genes under different treatments. Our results provide guidelines for reference gene selection for more accurate qRT-PCR quantification and will promote studies of gene expression in S. grandis subjected to environmental stress.

  17. Screening of Bread Wheat Genotypes for Stem Reserves Remobilization, Relative Water Content and Osmotic Adjustment under Drought Stress

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    Z Soleimani

    2015-05-01

    Full Text Available Drought one of the most important global threats against bread wheat production. In order to identify physiological traits associated with drought tolerance, 52 bread wheat varieties were cultured under two normal and drought stress condition in a randomized complete block desigen with three replications. RWC (in three independent times, leaf rolling, leaf silvering, days to flowering, days to maturity and stem reserve remobilization were investigeted. Also in a pot experiment osmotic adjustment of the varieties were measured at seedling stage. varieties Star and Bezostaya had the highest RWC (0.79 and 0.78, respectively. Osmotic adjustment in Rasol and Unknown11 were highest (0.58 and 0.56, respectively. Varieties Tipik, Unknown11 and Azar2 showed the least decrease in thousand grain weight after spraying with KI (4.8, 5.5 and 5.5, respectively. Also varieties Dez, Gaspard and MV-17 have the highest degree of leaf silvering and varieties Niknejad, Star and Kohdasht under drought stress were able than the other varieties bring their leaves to form a rolling and cope with water deficit. Under drought stress, Varieties Alborz, Zagros and Inia were observed premature than the other varieties and Gaspard and Kaslojen varieties were observed late mature than the other varieties. Altogetehr varieties Kohdasht, Star and Bezostaya can be used as genetic resources for leaf water retention under drought stress condition for imjproving other varieties. Also as Azar2 and Unknown11 had highest amount of thousand grain weight under normal condition and simoultanously showed high ability in stem reserves remobilization they can be selected as parents in crosses for improving these traits.

  18. Water-avoidance stress enhances gastric contractions in freely moving conscious rats: role of peripheral CRF receptors.

    Science.gov (United States)

    Nozu, Tsukasa; Kumei, Shima; Takakusaki, Kaoru; Okumura, Toshikatsu

    2014-05-01

    Stress alters gastrointestinal motility through central and peripheral corticotropin-releasing factor (CRF) pathways. Accumulating evidence has demonstrated that peripheral CRF is deeply involved in the regulation of gastric motility, and enhances gastric contractions through CRF receptor type 1 (CRF1) and delays gastric emptying (GE) through CRF receptor type 2 (CRF2). Since little is known whether water-avoidance stress (WAS) alters gastric motility, the present study tried to clarify this question and the involvement of peripheral CRF receptor subtypes in the mechanisms. We recorded intraluminal gastric pressure waves using a perfused manometric method. The rats were anesthetized and the manometric catheter was inserted into the stomach 4-6 days before the experiments. We assessed the area under the manometric trace as the motor index (MI), and compared this result with those obtained 1 h before and after initiation of WAS in nonfasted conscious rats. Solid GE for 1 h was also measured. WAS significantly increased gastric contractions. Intraperitoneal (ip) administration of astressin (100 μg/kg, 5 min prior to stress), a nonselective CRF antagonist, blocked the response to WAS. On the other hand, pretreatment (5 min prior to stress) with neither astressin2-B (200 μg/kg, ip), a selective CRF2 antagonist, nor urocortin 2 (30 μg/kg, ip), a selective CRF2 agonist, modified the response to WAS. These drugs did not alter the basal MI. WAS did not change GE. WAS may activate peripheral CRF1 but not CRF2 signaling and stimulates gastric contractions without altering GE.

  19. How plants cope with water stress in the field. Photosynthesis and growth.

    Science.gov (United States)

    Chaves, M M; Pereira, J S; Maroco, J; Rodrigues, M L; Ricardo, C P P; Osório, M L; Carvalho, I; Faria, T; Pinheiro, C

    2002-06-01

    Plants are often subjected to periods of soil and atmospheric water deficit during their life cycle. The frequency of such phenomena is likely to increase in the future even outside today's arid/semi-arid regions. Plant responses to water scarcity are complex, involving deleterious and/or adaptive changes, and under field conditions these responses can be synergistically or antagonistically modified by the superimposition of other stresses. This complexity is illustrated using examples of woody and herbaceous species mostly from Mediterranean-type ecosystems, with strategies ranging from drought-avoidance, as in winter/spring annuals or in deep-rooted perennials, to the stress resistance of sclerophylls. Differences among species that can be traced to different capacities for water acquisition, rather than to differences in metabolism at a given water status, are described. Changes in the root : shoot ratio or the temporary accumulation of reserves in the stem are accompanied by alterations in nitrogen and carbon metabolism, the fine regulation of which is still largely unknown. At the leaf level, the dissipation of excitation energy through processes other than photosynthetic C-metabolism is an important defence mechanism under conditions of water stress and is accompanied by down-regulation of photochemistry and, in the longer term, of carbon metabolism.

  20. Spectral changes in conifers subjected to air pollution and water stress: Experimental studies

    Science.gov (United States)

    Westman, Walter E.; Price, Curtis V.

    1988-01-01

    The roles of leaf anatomy, moisture and pigment content, and number of leaf layers on spectral reflectance in healthy, pollution-stressed, and water-stressed conifer needles were examined experimentally. Jeffrey pine (Pinus jeffreyi) and giant sequoia (Sequoiadendron gigantea) were exposed to ozone and acid mist treatments in fumigation chambers; red pine (Pinus resinosa) needles were artificially dried. Infrared reflectance from stacked needles rose with free water loss. In an air-drying experiment, cell volume reductions induced by loss of turgor caused near-infrared reflectance (TM band 4) to drop after most free water was lost. Under acid mist fumigation, stunting of tissue development similarly reduced band 4 reflectance. Both artificial drying and pollutant fumigation caused a blue shift of the red edge of spectral reflectance curves in conifers, attributable to chlorophyll denaturation. Thematic mapper band ratio 4/3 fell and 5/4 rose with increasing pollution stress on artificial drying. Loss of water by air-drying, freeze-drying, or oven-drying enhanced spectral features, due in part to greater scattering and reduced water absorption. Grinding of the leaf tissue further enhanced the spectral features by increasing reflecting surfaces and path length. In a leaf-stacking experiment, an asymptote in visible and infrared reflectance was reached at 7-8 needle layers of red pine.

  1. Forest productivity and water stress in Amazonia: observations from GOSAT chlorophyll fluorescence.

    Science.gov (United States)

    Lee, Jung-Eun; Frankenberg, Christian; van der Tol, Christiaan; Berry, Joseph A; Guanter, Luis; Boyce, C Kevin; Fisher, Joshua B; Morrow, Eric; Worden, John R; Asefi, Salvi; Badgley, Grayson; Saatchi, Sassan

    2013-06-22

    It is unclear to what extent seasonal water stress impacts on plant productivity over Amazonia. Using new Greenhouse gases Observing SATellite (GOSAT) satellite measurements of sun-induced chlorophyll fluorescence, we show that midday fluorescence varies with water availability, both of which decrease in the dry season over Amazonian regions with substantial dry season length, suggesting a parallel decrease in gross primary production (GPP). Using additional SeaWinds Scatterometer onboard QuikSCAT satellite measurements of canopy water content, we found a concomitant decrease in daily storage of canopy water content within branches and leaves during the dry season, supporting our conclusion. A large part (r(2) = 0.75) of the variance in observed monthly midday fluorescence from GOSAT is explained by water stress over moderately stressed evergreen forests over Amazonia, which is reproduced by model simulations that include a full physiological representation of photosynthesis and fluorescence. The strong relationship between GOSAT and model fluorescence (r(2) = 0.79) was obtained using a fixed leaf area index, indicating that GPP changes are more related to environmental conditions than chlorophyll contents. When the dry season extended to drought in 2010 over Amazonia, midday basin-wide GPP was reduced by 15 per cent compared with 2009.

  2. Can a canopy temperature-based stress index enhance water use efficiency in irrigated wine grape under arid conditions?

    Science.gov (United States)

    Enhancement of irrigation water use efficiency and water productivity in arid wine grape production regions is hindered by a lack of automated, real-time methods for monitoring and interpreting vine water status. A normalized, water stress index calculated from real-time vine canopy temperature meas...

  3. REDUCTION OF HERBICIDE AND WATER STRESS IN SPRING BARLEY BY REGULATORS OF POLYAMINE BIOSYNTHESIS

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    Pavol Trebichalský

    2014-02-01

    Full Text Available The experiment was carried out under artificial light of fluorescent lamps starting with 60 % full water capacity which was afterwards decreased on 40 % and finally the plants of barley were not watered. 30 plants of this cereal after plant emergence were thinned on 22 pieces. Experiment was treated by triazine herbicide, as well as its mixtures of regulators of polyamine synthesis: γ-aminobutyric acid, 1.3-propylenediamine dihydrochloride and salicyl acid. Solo application of triazine herbicide during water stress had negative balance on formation of root and above ground biomass. Addition of regulators of polyamine synthesis had positive effects on mentioned parameters, but not in comparison to control variant. These stress factors were eliminated most significantly only the application of GABA (100 g.ha-1 in mixture with herbicide.

  4. Effect of supplementation of water-soluble vitamins on oxidative stress and blood pressure in prehypertensives.

    Science.gov (United States)

    Talikoti, Prashanth; Bobby, Zachariah; Hamide, Abdoul

    2015-01-01

    The objective of the study was to evaluate the effect of water-soluble vitamins on oxidative stress and blood pressure in prehypertensives. Sixty prehypertensives were recruited and randomized into 2 groups of 30 each. One group received water-soluble vitamins and the other placebo for 4 months. Further increase in blood pressure was not observed in the vitamin group which increased significantly in the placebo group at the end of 4 months. Malonedialdehyde and protein carbonylation were reduced during the course of treatment with vitamins whereas in the placebo group there was an increase in the level of malondialdehyde. In conclusion, supplementation of water-soluble vitamins in prehypertension reduces oxidative stress and its progression to hypertension.

  5. Response of Short Duration Tropical Legumes and Maize to Water Stress: A Glasshouse Study

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    Hossain Sohrawardy

    2014-01-01

    Full Text Available The study was conducted as a pot experiment in the tropical glasshouse to evaluate the response of grain legumes (Phaseolus vulgaris, Vigna unguiculata, and Lablab purpureus in comparison to maize (Zea mays and estimate their potential and performance. Two experiments were established using completely randomized design. Physiological measurements (stomatal conductance, photosynthetic activities, and transpiration rates were measured using LCpro instrument. Scholander bomb was used for the measurement of plant cell water potential. Significant difference was observed in different plant species with increase of different water regimes. Among the legumes, L. purpureus showed better response in water stressed conditions. At the beginning, in dry watered treatment the photosynthetic rate was below 0 µmol m−2 s−1 and in fully watered condition it was 48 µmol m−2 s−1. In dry treatment, total dry weight was 10 g/pot and in fully watered condition it was near to 20 g/pot in P. vulgaris. The study concludes that water stress condition should be taken into consideration for such type of crop cultivation in arid and semiarid regions.

  6. Seed quality and water use characteristics of maize landraces compared with selected commercial hybrids

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    Farai Mazvimbakupa

    2015-03-01

    Full Text Available Understanding seed quality and water use characteristics of maize (Zea mays L. landraces will improve food security among subsistence farmers who still cultivate them. The objective of this study was to evaluate seed quality and water use characteristics of two maize landraces (GQ1 and GQ2 compared with two commercial hybrids (SC701 and PAN53. Seed quality was determined by the standard germination, electrical conductivity, and tetrazolium tests. A controlled environment study was conducted in which the landraces were compared with hybrids across three water treatments (30% ETc; 50% ETc, and 80% ETc. Although landrace GQ2 performed at par with the hybrids, overall, seed quality tests showed that hybrids had superior seed quality than landraces. This was also confirmed by highly significant emergence results (P < 0.001 from pot trials where SC701 and PAN53 had higher emergence (100% and 94.44%, respectively compared with GQ2 (86.11% and GQ1 (61.11%. Subjecting landraces and hybrids to water stress (50% and 30% ETc resulted in shorter plants with fewer leaves and earlier tasselling compared with non-stressed plants (80% ETc. Plant height for the 30% ETc water treatment was 156.1 cm compared with 175.8 cm for the 80% ETc water treatment, while plants under the 30% ETc water treatment tasseled at 105.4 d compared with 129.5 d for the 80% ETc water treatment. The GQ2 landrace continued to perform similar to, and often better, than the hybrid varieties, especially under stress conditions. Yield was poor under controlled conditions. Performance of the GQ2 landrace for both seed quality tests and under controlled conditions shows that landraces remain an important germplasm resource.

  7. Canopy Vegetation Indices from In situ Hyperspectral Data to Assess Plant Water Status of Winter Wheat under Powdery Mildew Stress.

    Science.gov (United States)

    Feng, Wei; Qi, Shuangli; Heng, Yarong; Zhou, Yi; Wu, Yapeng; Liu, Wandai; He, Li; Li, Xiao

    2017-01-01

    Plant disease and pests influence the physiological state and restricts the healthy growth of crops. Physiological measurements are considered the most accurate way of assessing plant health status. In this paper, we researched the use of an in situ hyperspectral remote sensor to detect plant water status in winter wheat infected with powdery mildew. Using a diseased nursery field and artificially inoculated open field experiments, we detected the canopy spectra of wheat at different developmental stages and under different degrees of disease severity. At the same time, destructive sampling was carried out for physical tests to investigate the change of physiological parameters under the condition of disease. Selected vegetation indices (VIs) were mostly comprised of green bands, and correlation coefficients between these common VIs and plant water content (PWC) were generally 0.784-0.902 ( p powdery mildew stress. The Photochemical Reflectance Index (PRI) was sensitive to physiological response influenced by powdery mildew, and the relationships of PRI with chlorophyll content, the maximum quantum efficiency of PSII photochemistry (Fv/Fm), and the potential activity of PSII photochemistry (Fv/Fo) were good with R 2 = 0.639, 0.833, 0.808, respectively. Linear regressions showed PRI demonstrated a steady relationship with PWC across different growth conditions, with R 2 = 0.817 and RMSE = 2.17. The acquired PRI model of wheat under the powdery mildew stress has a good compatibility to different experimental fields from booting stage to filling stage compared with the traditional water signal vegetation indices, WBI, FWBI 1 , and FWBI 2 . The verification results with independent data showed that PRI still performed better with R 2 = 0.819 between measured and predicted, and corresponding RE = 8.26%. Thus, PRI is recommended as a potentially reliable indicator of PWC in winter wheat with powdery mildew stress. The results will help to understand the physical state of

  8. Optimal crop selection and water allocation under limited water supply in irrigation

    Science.gov (United States)

    Stange, Peter; Grießbach, Ulrike; Schütze, Niels

    2015-04-01

    Due to climate change, extreme weather conditions such as droughts may have an increasing impact on irrigated agriculture. To cope with limited water resources in irrigation systems, a new decision support framework is developed which focuses on an integrated management of both irrigation water supply and demand at the same time. For modeling the regional water demand, local (and site-specific) water demand functions are used which are derived from optimized agronomic response on farms scale. To account for climate variability the agronomic response is represented by stochastic crop water production functions (SCWPF). These functions take into account different soil types, crops and stochastically generated climate scenarios. The SCWPF's are used to compute the wate