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Sample records for water stress conditions

  1. 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

  2. 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.

  3. 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)

  4. 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 ...

  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. 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.

  7. 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.

  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. 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.

  10. 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

  11. 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.

  12. Effect of surface stress state on dissolution property of Alloy 690 in simulated primary water condition

    International Nuclear Information System (INIS)

    Kim, Kyung Mo; Shim, Hee-Sang; Lee, Eun Hee; Seo, Myung Ji; Han, Jung Ho; Hur, Do Haeng

    2014-01-01

    The dissolution control of nickel is important to reduce the radioactive dose rate and deterioration of fuel performance in the operation of nuclear power plants (PWR). The corrosion properties are affected by the metal surface residual stress introduced in manufacture process such as work hardening. This work studied the effect of surface modification on the release rate of Alloy 690, nickel-base alloy for a steam generator tube, in the test condition of simulated primary water chemistry in PWRs. The surface stress modification was applied by the electro-polishing and shot peening method. Shot peening process was applied using ceramic beads with different intensities through the variation of air pressure. The corrosion release tests performed at 330degC with LiOH 2 ppm and H 3 BO 4 1200 ppm, DH(dissolved hydrogen) 35 cc/kg (STP) and about 20 ppb of DO(dissolved oxygen) condition. The corrosion release rate was evaluated by a gravimetric analysis method and the surface analysed by SEM and optical microscope. The surface residual stress was measured by an X-ray diffractometer, and the distribution of stress state was evaluated by a micro-hardness tester. The metal ion release rate of alloy 690 was evaluated from the influence of the stress state on the metal surface. The oxide property and structure was affected by the residual stress in the oxide layer. (author)

  13. 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.

  14. Effect of potassium chloride supplementation in drinking water on broiler performance under heat stress conditions.

    Science.gov (United States)

    Ahmad, T; Khalid, T; Mushtaq, T; Mirza, M A; Nadeem, A; Babar, M E; Ahmad, G

    2008-07-01

    The effect of water supplementation of KCl on performance of heat-stressed Hubbard broilers was evaluated in the present experiment. The 3 experimental treatments (i.e., control, 0.3 and 0.6% KCl) were allocated to 3 replicates of 15 birds each. The control group was kept on dugout tap water, whereas the other 2 groups were supplied water supplemented with 0.3 and 0.6% KCl (wt/vol) by supplementing 3 and 6 g of KCl, respectively, per liter of drinking water. Broilers were provided ad libitum access to feed and water for the experimental period of 7 to 42 d of age and kept in open-sided house. The birds were reared under continuous thermostress (minimum 28.2 +/- 1.02 and maximum 37.5 +/- 0.78 degrees C) environment. Supplementing drinking water with 0.6% KCl reduced panting-phase blood pH to 7.31 and significantly increased live BW gain by 14.5 (P = 0.036) and 7.9% (P = 0.029) at 28 and 42 d of age, respectively, relative to control. An improved (P = 0.04) feed:gain and lowered body temperature were noted in groups supplemented with 0.6% KCl as compared with control and 0.3% KCl. Enhanced physiological adaptation with 0.6% KCl was evidenced by a more favorable pH during the panting phase in the present study. These findings demonstrated a possibility of better broiler live performance through KCl supplementation under conditions of severe heat stress (35 to 38 degrees C).

  15. The sensitivity of Sphagnum to surface layer conditions in a re-wetted bog: a simulation study of water stress

    NARCIS (Netherlands)

    Schouwenaars, J.M.; Gosen, A.M.

    2007-01-01

    The behaviour of the water table in re-wetted bogs varies widely between different locations so that recolonising Sphagnum is vulnerable to water stress, especially when the water table is drawn down in summer. It is important to understand how physical site conditions influence the occurrence of

  16. Effect of heat treatment conditions on stress corrosion cracking resistance of alloy X-750 in high temperature water

    International Nuclear Information System (INIS)

    Yonezawa, Toshio; Onimura, Kichiro; Sakamoto, Naruo; Sasaguri, Nobuya; Susukida, Hiroshi; Nakata, Hidenori.

    1984-01-01

    In order to improve the resistance of the Alloy X-750 in high temperature and high purity water, the authors investigated the influence of heat treatment condition on the stress corrosion cracking resistance of the alloy. This paper describes results of the stress corrosion cracking test and some discussion on the mechanism of the stress corrosion cracking of Alloy X-750 in deaerated high temperature water. The following results were obtained. (1) The stress corrosion cracking resistance of Alloy X-750 in deaerated high temperature water remarkably depended upon the heat treatment condition. The materials solution heat treated and aged within temperature ranges from 1065 to 1100 0 C and from 704 to 732 0 C, respectively, have a good resistance to the stress corrosion cracking in deaerated high temperature water. Especially, water cooling after the solution heat treatment gives an excellent resistance to the stress corrosion cracking in deaerated high temperature water. (2) Any correlations were not observed between the stress corrosion cracking susceptibility of Alloy X-750 in deaerated high temperature water and grain boundary chromium depleted zones, precipitate free zones and the grain boundary segregation of impurity elements and so on. It appears that there are good correlations between the stress corrosion cracking resistance of the alloy in the environment and the kinds, morphology and coherency of precipitates along the grain boundaries. (author)

  17. Cracks propagation by stress corrosion cracking in conditions of Boiling Water Reactor (BWR)

    International Nuclear Information System (INIS)

    Fuentes C, P.

    2003-01-01

    This work presents the results of the assays carried out in the Laboratory of Hot Cells of the National Institute of Nuclear Research (ININ) to a type test tube Compact Tension (CT), built in steel austenitic stainless type 304L, simulating those conditions those that it operates a Boiling Water Reactor (BWR), at temperature 288 C and pressure of 8 MPa, to determine the speed to which the cracks spread in this material that is of the one that different components of a reactor are made, among those that it highlights the reactor core vessel. The application of the Hydrogen Chemistry of the Water is presented (HWC) that is one alternative to diminish the corrosion effect low stress in the component, this is gets controlling the quantity of oxygen and of hydrogen as well as the conductivity of the water. The rehearsal is made following the principles of the Mechanics of Elastic Lineal Fracture (LEFM) that considers a crack of defined size with little plastic deformation in the tip of this; the measurement of crack advance is continued with the technique of potential drop of direct current of alternating signal, this is contained inside the standard Astm E-647 (Method of Test Standard for the Measurement of Speed of Growth of Crack by fatigue) that is the one that indicates us as carrying out this test. The specifications that should complete the test tubes that are rehearsed as for their dimensions, it forms, finish and determination of mechanical properties (tenacity to the fracture mainly) they are contained inside the norm Astm E-399, the one which it is also based on the principles of the fracture mechanics. The obtained results were part of a database to be compared with those of other rehearsals under different conditions, Normal Chemistry of the Water (NWC) and it dilutes with high content of O 2 ; to determine the conditions that slow more the phenomena of stress corrosion cracking, as well as the effectiveness of the used chemistry and of the method of

  18. Study of Sesame (Sesame indicum L. Cultivars based on Morphological Characteristics Under Water Deficit Stress Condition Using Factor Analysis

    Directory of Open Access Journals (Sweden)

    A Asghari

    2014-03-01

    Full Text Available In order to evaluation sesame cultivars based on morphological characteristics under water deficit stress condition using factor analysis, an experiment was conducted as a split plot based on randomized complete block design with three replications during 2009 in Research Center of Agriculture and Natural Resources in Parsabad. In this experiment, irrigation as the main factor at three levels (50, 75 and 100 percent of crop water requirement and ten sesame cultivars as the sub-factor were studied. The water requirement of sesame was calculated using CROPWAT software (Penman-Monteith method according to FAO-56. Results showed significant differences between the cultivars and the irrigation levels for all studied traits. Interaction between cultivars and irrigation levels was significant for some of traits. Comparisons of means showed that in water deficit condition, yield and all of traits reduced. In all traits the greatest amounts observed in complete irrigation treatment. In 50 percent of water requirement treatment, amount of leaf chlorophyll, root length, root branches and root length/plant height ratio were greater than other treatments. The Karaj1, Ultan, Naze and IS cultivars were better than other cultivars in stress and non stress condition. In factor analysis 5 and 4 first factors in non stress and stress condition explained 91.36 and 89.52 percent of trait variance, respectively. Grouping of sesame cultivars based on first and second factors in non stress conditions showed that Karaj1, Ultan and Naze cultivars were better than other cultivars. Also, in stress conditions Karaj1 and Ultan cultivars grouped as water deficit stress and better cultivars.

  19. Genotype x environment interaction for grain yield of wheat genotypes tested under water stress conditions

    International Nuclear Information System (INIS)

    Sail, M.A.; Dahot, M.U.; Mangrio, S.M.; Memon, S.

    2007-01-01

    Effect of water stress on grain yield in different wheat genotypes was studied under field conditions at various locations. Grain yield is a complex polygenic trait influenced by genotype, environment and genotype x environment (GxE) interaction. To understand the stability among genotypes for grain yield, twenty-one wheat genotypes developed Through hybridization and radiation-induced mutations at Nuclear Institute of Agriculture (NIA) TandoJam were evaluated with four local check varieties (Sarsabz, Thori, Margalla-99 and Chakwal-86) in multi-environmental trails (MET/sub s/). The experiments were conducted over 5 different water stress environments in Sindh. Data on grain yield were recorded from each site and statistically analyzed. Combined analysis of variance for all the environments indicated that the genotype, environment and genotype x environment (GxE) interaction were highly significant (P greater then 0.01) for grain yield. Genotypes differed in their response to various locations. The overall highest site mean yield (4031 kg/ha) recorded at Moro and the lowest (2326 kg/ha) at Thatta. Six genotypes produced significantly (P=0.01) the highest grain yield overall the environments. Stability analysis was applied to estimate stability parameters viz., regression coefficient (b), standard error of regression coefficient and variance due to deviation from regression (S/sub 2/d) genotypes 10/8, BWS-78 produced the highest mean yield over all the environments with low regression coefficient (b=0.68, 0.67 and 0.63 respectively and higher S/sup 2/ d value, showing specific adaptation to poor (un favorable) environments. Genotype 8/7 produced overall higher grain yield (3647 kg/ha) and ranked as third high yielding genotype had regression value close to unity (b=0.9) and low S/sup d/ value, indicating more stability and wide adaptation over the all environments. The knowledge of the presence and magnitude of genotype x environment (GE) interaction is important to

  20. AgRISTARS: Early warning and crop condition assessment. Plant cover, soil temperature, freeze, water stress, and evapotranspiration conditions

    Science.gov (United States)

    Wiegand, C. L. (Principal Investigator); Nixon, P. R.; Gausman, H. W.; Namken, L. N.; Leamer, R. W.; Richardson, A. J.

    1981-01-01

    Emissive (10.5 to 12.5 microns) and reflective (0.55 to 1.1 microns) data for ten day scenes and infrared data for six night scenes of southern Texas were analyzed for plant cover, soil temperature, freeze, water stress, and evapotranspiration. Heat capacity mapping mission radiometric temperatures were: within 2 C of dewpoint temperatures, significantly correlated with variables important in evapotranspiration, and related to freeze severity and planting depth soil temperatures.

  1. Effect of drought stress on water status, electrolyte leakage and enzymatic antioxidants of kochia (kochia scoparia) under saline condition

    International Nuclear Information System (INIS)

    Masoumi, A.; Kafi, M.; Khazaei, Z.; Davari, K.

    2010-01-01

    Drought stress is considered as the main factor of yield limitations in arid and semi-arid areas, where drought and salinity stresses are usually combined. Kochia species have recently attracted the attention of researchers as forage and fodder crop in marginal lands worldwide due to its drought and salt tolerant characters. This field experiment was performed at the Salinity Research Station (36 deg. 15'N, 59 deg. 28' E) of Ferdowsi University, ashhad, Iran in 2008, in a split plot based on randomized complete block design with three replications. Three levels of drought stress (control, no irrigation in vegetative stage (recovery treatment) and no irrigation at reproductive stage for one month (stress treatment)), and two Kochia ecotypes (Birjand and Borujerd) were allocated as main and sub-plots, respectively. Relative water content (RWC), membrane permeability and antioxidant enzymes were assayed at the beginning of anthesis. Stress treatment caused a significant decrease in the leaf RWC and increase in electrolyte leakage compared with control and recovered conditions. Furthermore, stress treatment caused a significant increase in antioxidant enzyme activities except of superoxide dismutase (SOD) and peroxidase (POX). The Birjand ecotype was significantly more tolerant to drought than Borujerd ecotype. According to the results, there were no difference between recovered plants and control treatment, therefore, Kochia can recover quickly after removing drought stress. Kochia showed high tolerance against drought and salinity stresses and different antioxidant enzymes had different behavior under stress conditions. (author)

  2. estimating water consumptive use for some crops under stress conditions using neutron scattering method

    International Nuclear Information System (INIS)

    Salama, M.A.A.A.

    2011-01-01

    Field experiment was conducted to study the influence of different levels of irrigation water salinity on actual evapotranspiration, water stress coefficient, yield and water use efficiency of both groundnut and wheat crops growing on sandy soil under trickle irrigation system located at 30 o 24 ' N latitude, 31 o 35 ' E longitude while the altitude is 20 m above the sea level.Four irrigation water salinity levels were used for both crops, they are; 2.4 (S 1 ), 2.7 (S 2 ), 3.3 (S 3 ) and 4.4 (S 4 ) dS m -1 , for groundnut and 4.9 (S 1 ), 6.3 (S 2 ), 8.7 (S 3 ) and 13 (S 4 ) dS m -1 , for wheat respectively besides a fresh water (FW) as a control treatment (0.5 dS m -1 ). Cattle manure was added as a soil amendment at a rate of 48 m 3 ha -1 . Neutron moisture meter was used to determine soil moisture content and depletion through the soil depths of 30, 45, 60, 75 and 90cm. Soil moisture content at 15 cm soil depth was determined gravimetrically. The applied irrigation water was 700 mm/season for groundnut and 550 mm/season for wheat based on 100 % of the recommended crop water requirements according to FAO No.33. (1979). The obtained results showed that the actual evapotranspiration (ET a ) and water stress coefficient (K s ) were slightly deceased by increasing the salinity of irrigation water especially under (S 4 ) irrigation salinity treatment for both crops.

  3. Growth, phenology and chlorophyll fluorescence of habanero pepper (Capsicum chinense Jacq. under water stress conditions

    Directory of Open Access Journals (Sweden)

    Alfonzo Pérez-Gutiérrez

    2017-04-01

    Full Text Available The irrigation methods offer a good alternative for increasing water use efficiency. The main purpose of this study was to identify the best irrigation level for Habanero pepper (Capsicum chinense Jacq. plants based on available water capacity (AWC of substrate. An experiment carried out with three irrigation levels (20, 40 and 60% of AWC and five genotypes (H225, H241, H244, H226 and Jaguar. The irrigation level of 20% decreased the soil water potential to cause water stress in plants. At an irrigation level of 40%, average jaguar plant height (92 cm and H241 (79 cm, genotypes were greater than under the other treatments. Average leaf area of H225, H241 and H244 plants was at least 48% greater than Jaguar plants. Average total dry matter of H241 and Jaguar plants, were 30 and 28% greater than H226 plants; and values of maximum photochemical quantum yield (Fv/Fm, relative electron transport rate and effective photochemical quantum yield of photosystem II were higher in H241, H244 and H226 plants; i.e. they are less probably due to photo inhibition damage. However, flowering time was earlier in plants with an irrigation level (IL of 20% than plants with an IL of 40%, this was a consequence of stress due to water deficit. The 60% irrigation treatment caused flooding and all genotypes died before the inflorescence stage. These results suggest the enforcement of a suitable irrigation level based in available water capacity of substrate coupled with a vigorous genotype can encourage healthy plants and high water use efficiency.

  4. Temperature and water stress during conditioning and incubation phase affecting Orobanche crenata seed germination and radicle growth

    Directory of Open Access Journals (Sweden)

    JUAN eMORAL

    2015-06-01

    Full Text Available Orobanche crenata is a holoparasitic plant that is potentially devastating to crop yield of legume species. Soil temperature and humidity are known to affect seed germination, however, the extent of their influence on germination and radicle growth of those of O. crenata is largely unknown. In this work, we studied the effects of temperature, water potential (Ψt and the type of water stress (matric or osmotic on O. crenata seeds during conditioning and incubation periods. We found that seeds germinated between 5 and 30ºC during both periods, with a maximum around 20ºC. Germination increased with increasing Ψt from -1.2 to 0 MPa during conditioning and incubation periods. Likewise, seed germination increased logarithmically with length of conditioning period until 40 days. The impact of the type of water stress on seed germination was similar, although the radicle growth of seeds under osmotic stress was lower than under matric stress, what could explain the lowest infestation of Orobanche spp. in regions characterized by saline soil. The data in this study will be useful to forecast infection of host roots by O. crenata.

  5. Temperature and water stress during conditioning and incubation phase affecting Orobanche crenata seed germination and radicle growth.

    Science.gov (United States)

    Moral, Juan; Lozano-Baena, María Dolores; Rubiales, Diego

    2015-01-01

    Orobanche crenata is a holoparasitic plant that is potentially devastating to crop yield of legume species. Soil temperature and humidity are known to affect seed germination, however, the extent of their influence on germination and radicle growth of those of O. crenata is largely unknown. In this work, we studied the effects of temperature, water potential (Ψt) and the type of water stress (matric or osmotic) on O. crenata seeds during conditioning and incubation periods. We found that seeds germinated between 5 and 30°C during both periods, with a maximum around 20°C. Germination increased with increasing Ψt from -1.2 to 0 MPa during conditioning and incubation periods. Likewise, seed germination increased logarithmically with length of conditioning period until 40 days. The impact of the type of water stress on seed germination was similar, although the radicle growth of seeds under osmotic stress was lower than under matric stress, what could explain the lowest infestation of Orobanche sp. in regions characterized by saline soil. The data in this study will be useful to forecast infection of host roots by O. crenata.

  6. Effect of Zeolite and Nitrogen Fertilizer Application under Water Deficit Stress Conditions on Agronomical and Physiological Traits of Rapeseed

    Directory of Open Access Journals (Sweden)

    A. Ghiasvand Ghiasi

    2014-08-01

    Full Text Available In order to evaluation of zeolite and nitrogen fertilizer application effect on agronomic and physilogical traits of rapeseed (cv RGS003 under water deficit stress conditions, an experiment was conducted in factorial based on randomized complete block design with three replications during 2010 in Qazvin region, Iran. In the where, the two levels of irrigation factor as the normal irrigation (irrigation after 80 mm evaporation from class A pan as control and irrigation cease from stem elongation stage till end of growth, nitrogen factor was at three levels (0, 75 and 150 kg.ha-1 and zeolite factor (0 and 10tons per hectare were studied. Results showed that drought stress decreased evaluated traits such as silique per plant (41%, grain per silique (26%, 1000 seed weight (33%, grain yield (52.5%, oil percent (14%, RWC (31.5% and chlorophyll content (35%. Non-application of nitrogen had adverse effects on total traits and reduced them. However, zeolite application at water deficit stress conditions had positive and significant effect on total traits except of oil percent and chlorophyll content, specially improved grain yield and oil yield. Based on the results of this experiment, application of zeolite (10ton/ha-1 through storage and maintenance of water and nutrients, reduced the intensity and harmful effects of stress in plants and enhances crop yield.

  7. 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)

  8. Response of Barley Double Haploid Lines to the Grain Yield and Morphological Traits under Water Deficit Stress Conditions

    Directory of Open Access Journals (Sweden)

    Maroof Khalily

    2017-04-01

    Full Text Available To study the relationships of grain yield and some of agro-morphological traits in 40 doubled haploid (DH lines along with parental and three check genotypes in a randomized complete block design with two replications under two water regimes (normal and stress were evaluated during 2011-2012 and 2012-2013 growing seasons. Combined analysis of variance showed significant difference for all the traits in terms of the year, water regimes, lines, and and line × year. Comparison of group means, between non-stress and stress conditions, showed that DH lines had the lowest reduction percentage for the number of grains per spike, thousand grain weight, grain yield and biological yield as opposed to check genotypes. The correlation between grain yield with biological yield, harvest index, thousand grain weight, and hectoliter of kernel weight in both conditions, were highly significant and positive. Based on stepwise regression the peduncle length, number of seeds per spike, thousand seed weight, and hectoliter of kernel weight had important effect on increasing seed yield. The result of path analysis showed that these traits had the highest direct effect on grain yield. Based on mean comparisons of morphological characters as well as STI and GMP indices it can be concluded that lines No.11, 13, 14, 24, 29, 30, 35 and 39 were distinguished to be desirable lines for grain yield and their related traits and also tolerant lines in terms of response to drought stress conditions.

  9. Determining the Threshold Value of Basil Yield Reduction and Evaluation of Water Uptake Models under Salinity Stress Condition

    OpenAIRE

    M. Sarai Tabrizi; H. Babazadeh; M. Homaee; F. Kaveh Kaveh; M. Parsinejad

    2016-01-01

    Introduction: Several mathematical models are being used for assessing the plant response to the salinity of the root zone. The salinity of the soil and water resources is a major challenge for agricultural sector in Iran. Several mathematical models have been developed for plant responses to the salinity stress. However, these models are often applicable in particular conditions. The objectives of this study were to evaluate the threshold value of Basil yield reduction, modeling Basil respon...

  10. Farmer Resettlements and Water Energy Stresses Arising From Aggravating Drought Conditions in Mahaweli River Watershed, Sri Lanka

    Science.gov (United States)

    Thabrew, L.

    2012-12-01

    Climate change is expected to cause significant changes in water quantity and water quality in river basins throughout the world, with particularly significant impacts in developing regions. Climate change effects are often exacerbated by other simultaneous activities in developing countries, such as population growth, reliance on subsistence agriculture, and expanding provision of electricity. Each of these activities requires access to readily-available freshwater. For example, population growth requires more water for irrigation as food production needs increase. Additionally, water is needed for generating electricity in hydropower facilities as well as other facilities, which require water to run steam turbines or to cool facilities. As such, many developing countries face the real and immediate need to anticipate and adapt to climatic stresses on water resources in both the agricultural and residential sectors. Water withdrawal in both of these sectors is largely driven by individual behaviors, such as electricity use in the home and irrigation practices on farmland, aggregated at the household, community, and regional level. Our ongoing project in Sri Lanka focuses on understanding aforementioned issues in coupled natural and human systems in the Mahaweli River Watershed (MWR) to inform decision-makers to streamline policies and strategies for effective adaptation to worsening drought conditions. MWR produces more than 60% of the rice demand and nearly 40% of the energy requirement of the country. Although irrigation is currently the sector that withdraws the most water, with government plans for resettling farmer communities and developing new urban centers in the region by 2030, electricity production is expected to compete for water against irrigation in the future. Thus, understanding the water-energy nexus is crucial to planning for conservation and efficiency. Through a pilot survey conducted by our interdisciplinary research team, in five locations in

  11. Plant osmoregulation as an emergent water-saving adaptation under salt-stress conditions

    Science.gov (United States)

    Perri, S.; Entekhabi, D.; Molini, A.

    2017-12-01

    Ecohydrological models have been widely used in studying plant-environment relations and hydraulic traits in response to water, light and nutrient limitations. In this context, models become a tool to investigate how plants exploit available resources to maximize transpiration and growth, eventually pointing out possible pathways to adaptation. In contrast, ecohydrologists have rarely focused on the effects of salinity on plant transpiration, which are commonly considered marginal in terrestrial biomes. The effect of salinity, however, cannot be neglected in the case of salt affected soils - estimated to cover over 9 billion ha worldwide - and in intertidal and coastal ecosystems. The objective of this study is to model the effects of salinity on plant-water relations in order to better understand the interplay of soil hyperosmotic conditions and osmoregulation strategies in determining different transpiration patterns. Salinity reduces the water potential, therefore is expected to affect the plant hydraulics and reduce plant conductance (eventually leading to cavitation for very high salt concentrations). Also, plant adaptation to short and long-term exposure to salinity comes into place to maintain an efficient water and nutrients uptake. We introduce a parsimonious soil-plant-atmosphere continuum (SPAC) model that incorporates parameterizations for morphological, physiological and biochemical mechanisms involving varying salt concentrations in the soil water solution. Transpiration is expressed as a function of soil water salinity and salt-mediated water flows within the SPAC (the conceptual representation of the model is shown in Figure c). The model is used to explain a paradox observed in salt-tolerant plants where maximum transpiration occurs at an intermediate value of salinity (CTr,max), and is lower in more fresh (CTr,max) and more saline (C>CTr,max) conditions (Figure a and b). In particular, we show that - in salt-tolerant species - osmoregulation

  12. Germination and vigor of linseed seeds under different conditions of light, temperature and water stress

    Directory of Open Access Journals (Sweden)

    Raquel Stefanello

    2017-06-01

    Full Text Available Linseed (Linum usitatissimum L., cultivated from seeds, is one of the oldest plants domesticated by humans and is popularly used as a medicine. It can be used as the raw material to produce oil and bran because it has high lipids content, fiber and proteins. Based on the economic potential of this species and the need for more information about its physiology, the goal of this study was to analyze the effects of light, temperature and water stress on the germination and vigor of linseed seeds. In experiment I the seeds were sown on paper at constant temperatures of 15, 20, 25 and 30 ºC in the presence and absence of light. In experiment II, the seeds were placed on paper germitest soaked in solutions of polyethylene glycol (PEG 6000 at osmotic potentials corresponding to zero, -0.10, -0.20, -0.30, -0.40, -0.50 and -0.60 MPa. To evaluate the physiological potential, the following tests were made: germination, first germination count, length and dry mass of seedlings, and water stress. It was found that the highest percentages of germination and vigor occurred at a constant temperature of 20 °C, both in the presence and absence of light. The reduction of the osmotic potential of the substrate promoted a significant decrease in the germination and vigor of the linseed seeds. Osmotic potentials equal or less than -0.30 MPa were harmful to germination and there was no normal seedling development starting at -0.50 MPa.

  13. Physiological factors affecting intrinsic water use efficiency of potato clones within a dihaploid mapping population under well-watered and drought-stressed conditions

    DEFF Research Database (Denmark)

    Topbjerg, Henrik Bak; Kaminski, Kacper Piotr; Markussen, Bo

    2014-01-01

    ) within a dihaploid potato (Solanum tuberosum L.) mapping population under well-watered (WW) and drought-stress (DS) conditions. The factorial dependency of WUEi on several plant bio-physiological traits was analyzed, and clonal difference of WUEi was compared. Significant differences in WUEi were found......Optimizing crops water use is essential for ensuring food production under future climate scenarios. Therefore, new cultivars that are capable of maintaining production under limited water resource are needed. This study screened for clonal differences in intrinsic water use efficiency (WUEi...

  14. Effect of magnetic field and silver nanoparticles on yield and water use efficiency of Carum copticum under water stress conditions

    Directory of Open Access Journals (Sweden)

    Seghatoleslami Mohammadjavad

    2015-03-01

    Full Text Available Normally the productivity of cropping systems in arid and semi- arid regions is very low. The sustainable agricultural systems try to find out environmental friendly technologies based on physical and biological treatments to increase crop production. In this study two irrigation treatments (control and water stress and six methods of fertilizer treatment (control, NPK-F, using magnetic band- M, using silver nano particles- N, M+N and M+N+50% F on performance of ajowan were compared. Results showed that treatments with magnetic field or base fertilizer had more yield compared to the control and silver nanoparticles (N treatments. Application of silver nanoparticles had no positive effect on yield. The highest seed and biomass WUE achieved in base fertilizer or magnetic field treatments. Under water stress treatment, seed WUE significantly increased. In conclusion magnetic field exposure, probably by encourage nutrient uptake efficiency could be applied to reduce fertilizer requirement. On the other hand the cultivation of plants under low MF could be an alternative way of WUE improving.

  15. Dry Matter Accumulation and Remobilization in Grain Sorghum Genotypes (Sorghum bicolor L. Moench (underNormal and Water Stress Conditions

    Directory of Open Access Journals (Sweden)

    A Beheshti

    2011-02-01

    Full Text Available Abstract Production, remobilization and accumulation of assimilates in crops especially under water stress are essential factors for determination and studying the yield differences of species and cultivars. Field experiment was conducted using a split plot design based on a randomized complete block design with 3 replication s during 2007 growing season in agricultural research station (Khorasan Agricultural and Natural Resource Research Center, Mashhad-Iran. Main plots were consisted of 2 levels of water, water deficit after anthesis and normal condition (with out water stress and factorial arrangement of photosynthesis status (non desiccation and chemical desiccation with potassium iodide and 3 grain sorghum genotypes (Sepide, M5 and M2 promising lines were assigned to sub plots. Results of variance analysis showed, that the effects of water stress on dry matter accumulation, efficiency of remobilization (REE, percent of remobilization (REP, biologic yield were significant in (p≤0.01 (and grain yield (economic yield was significant in p≤0.05, respectively. Water deficit caused an increase of 10.08%, 24.45 % and 12.43% in dry matter accumulation, percent of remobilization and efficiency of remobilization, respectively as compared to normal conditions. This in turn was led to decrease in seed yield, biological yield and harvest index by 36.38%, 5.43% and 31.60%, respectively. The effect of disturbance in current photosynthesis was significant in all of traits and caused the increase of 15.58%, 17.5% and 36.62% in dry matter accumulation, efficiency of remobilization and percent of remobilization, respectively. The role of remobilization was crucial in sorghum genotypes. Interaction between factors showed that highest dry matter accumulation, percentage of remobilization and efficiency of remobilization was in drought stress and disturbance in current photosynthesis and was 16.62%, 62.54 and 24.60%, respectively and was significantly

  16. The Effect of Water Stress and Polymer on Water Use Efficiency, Yield and several Morphological Traits of Sunflower under Greenhouse Condition

    Directory of Open Access Journals (Sweden)

    Hossein NAZARLI

    2010-12-01

    Full Text Available In many part of Iran, the reproductive growth stages of sunflower (Helianthus annuus L. are exposed to water deficit stress. Therefore, the investigation of irrigation management in the farm conditions is a necessary element for increasing irrigation efficiency and decreasing water losses. The objective of present study was to investigate the effect of different rates of super absorbent polymer and levels of water stress on water use efficiency (WUE, yield and some morphological traits of sunflower (cultivar Master. Factorial experiment was carried out in completely randomized design with 3 replications. Factors were water stress in three levels (irrigation in 0.75; 0.50 and 0.25% of field capacity and super absorbent polymer in five levels (0; 0.75; 0.150; 2.25; 3 g/kg of soil. Super absorbent polymer was added in eight leaves stage of sunflower to pots in deepness of roots development. Water stress treatment was also applied in this growth stage of sunflower. For stress application, pots were weighted every day and irrigated when soil water received to 0.75; 0.50 and 0.25 of field capacity, respectively. The results of ANOVA indicated that the effect of different rates of super absorbent polymer and different rates of consumed water in all traits were significant. ANOVA also revealed that the interactive effects of two mentioned factors were significant except for seed yield trait. Polynomial model based on the ANOVA results was fitted for each trait. The results indicated that water stress significantly convert in decreasing the number of leaves per plant, chlorophyll content, 100 weight of seeds, seed yield and WUE in sunflower, whereas the application of super absorbent polymer moderated the negative effect of deficit irrigation, especially in high rates of polymer (2.25 and 3 g/kg of soil. The above mentioned rates of polymer have the best effect to all characteristics of sunflower in all levels of water stress treatment. The findings

  17. 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...

  18. Toxicity assessment of multi-walled carbon nanotubes on Cucurbita pepo L. under well-watered and water-stressed conditions.

    Science.gov (United States)

    Hatami, Mehrnaz

    2017-08-01

    The rapid increase in the production and application of various types of nanomaterials increases the possibility of their presence in total environment, which subsequently raises concerns about their potential threats to the first trophic level of organisms, specifically under varying environmental constraints. In this work, seeds of Cucurbita pepo L. were cultured in MS basal medium exposed to multi-walled carbon nanotubes (MWCNTs) at different concentrations (0, 125, 250, 500 and 1000μgmL -1 ) under two levels of water potential, well-watered (0MPa) and water stress (-1.5MPa) induced by polyethylene glycol (PEG 6000) for 14 days. Seeds exposed to MWCNTs showed reduction in germination percentage, root and shoot length, biomass accumulation and vigor index in a dose-dependent manner. However, seedlings germinated in MWCNTs-fortified media had significantly lower germination and growth attributes than those of control under water stress conditions. This happened due to increased oxidative injury indices including hydrogen peroxide (H 2 O 2 ), and malondialdehyde (MDA) contents, as well as electrolyte leakage index (ELI) of tissues. The impaired morpho-physiological and biochemical processes of seedlings exposed to different concentrations of MWCNTs under both PEG-induced stress and non-stress growing conditions were consequence of changes in the activation of various cellular antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (POD). Taken together, our findings reveal that MWCNTs played negative role on seed germination and subsequent growth of C. pepo L. seedlings under both levels of water potential. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Evaluation of drought tolerance and yield capacity of barley (hordeum vulgare) genotypes under irrigated and water-stressed conditions

    International Nuclear Information System (INIS)

    Khokhar, M.I.; Silva, J.A.T.D

    2012-01-01

    Twelve barley genotypes developed through different selection methods were evaluated under drought and irrigated conditions. The results of a correlation matrix revealed highly significant associations between Grain Yield (Yp) and Mean Productivity (MP), Stress Tolerance Index (STI), Geometric Mean Productivity (GMP) and Yield Index (Yi) under irrigated conditions while the Mean Productivity (MP), Yield Stability Index (Yi), Stress Tolerance Index (STI), Geometric Mean Productivity (GMP) and Yield Index (Yi) had a high response under stressed condition. Based on a principal component analysis, Geometric Mean Productivity (GMP), Mean Productivity (MP) and Stress Tolerance Index (STI) were considered to be the best parameters for selection of drought-tolerant genotypes. The 2-row barley genotypes B-07023 and B-07021 performed better in yield response under drought conditions and were more stable under stress conditions. Furthermore, drought stress reduced the yield of some genotypes while others were tolerant to drought, suggesting genetic variability in this material for drought tolerance. (author)

  20. Applicability of adapted reservoir operation for water stress mitigation under dry year conditions

    NARCIS (Netherlands)

    Olsson, O.; Ikramova, M.; Bauer, M.; Froebrich, J.

    2010-01-01

    This paper introduces the conjunctive use of a deterministic water quality model and water balance criteria for supporting the assessment of simulation and to evaluate the effectiveness of proposed operation strategies. By this, the applicability of enhanced reservoir operation strategies addressing

  1. 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

  2. Verification of an optimized condition for low residual stress employed water-shower cooling during welding in austenitic stainless steel plates

    International Nuclear Information System (INIS)

    Yanagida, N.; Enomoto, K.; Anzai, H.

    2004-01-01

    To reduce tensile residual stress in a welded region, we have developed a new cooling method that uses a water-shower behind the welding torch. When this method is applied to the welding of austenitic stainless steel, the welding and cooling conditions mainly determine how much the residual stress can be reduced. To optimize these conditions, we first used a robust design method to determine the effects of the preheating temperature, the heat input quantity, and the water-shower area on the residual stress, and found that, to decrease the tensile residual stress, the preheating temperature should be high, the heat input low, and the water-shower area large. To confirm the effectiveness of these optimized conditions, the residual stresses under optimized or non-optimized conditions were measured experimentally. It was found that the residual stresses were tensile under the non-optimized conditions, but compressive under the optimized ones. These measurements agree well with the 3D-FEM analyses. It can therefore be concluded that the optimized conditions are valid and appropriate for reducing residual stress in an austenitic stainless-steel weld. (orig.)

  3. Nod factor supply under water stress conditions modulates cytokinin biosynthesis and enhances nodule formation and N nutrition in soybean.

    Science.gov (United States)

    Prudent, Marion; Salon, Christophe; Smith, Donald L; Emery, R J Neil

    2016-09-01

    Nod factors (NF) are molecules produced by rhizobia which are involved in the N 2 -fixing symbiosis with legume plants, enabling the formation of specific organs called nodules. Under drought conditions, nitrogen acquisition by N 2 -fixation is depressed, resulting in low legume productivity. In this study, we evaluated the effects of NF supply on nitrogen acquisition and on cytokinin biosynthesis of soybean plants grown under drought. NF supply to water stressed soybeans increased the CK content of all organs. The profile of CK metabolites also shifted from t-Z to cis-Z and an accumulation of nucleotide and glucoside conjugates. The changes in CK coincided with enhanced nodule formation with sustained nodule specific activity, which ultimately increased the total nitrogen fixed by the plant.

  4. Plant cover, soil temperature, freeze, water stress, and evapotranspiration conditions. [south Texas

    Science.gov (United States)

    Wiegand, C. L.; Nixon, P. R.; Gausman, H. W.; Namken, L. N.; Leamer, R. W.; Richardson, A. J. (Principal Investigator)

    1981-01-01

    Emissive and reflective data for 10 days, and IR data for 6 nights in south Texas scenes were analyzed after procedures were developed for removing cloud-affected data. HCMM radiometric temperatures were: within 2 C of dewpoint temperatures on nights when air temperature approached dewpoint temperatures; significantly correlated with variables important in evapotranspiration; and, related to freeze severity and planting depth soil temperatures. Vegetation greenness indexes calculated from visible and reflective IR bands of NOAA-6 to -9 meteorological satellites will be useful in the AgRISTARS program for seasonal crop development, crop condition, and drought applications.

  5. Strobilurin fungicides induce changes in photosynthetic gas exchange that do not improve water use efficiency of plants grown under conditions of water stress.

    Science.gov (United States)

    Nason, Mark A; Farrar, John; Bartlett, David

    2007-12-01

    The effects of five strobilurin (beta-methoxyacrylate) fungicides and one triazole fungicide on the physiological parameters of well-watered or water-stressed wheat (Triticum aestivum L.), barley (Hordeum vulgare L.) and soya (Glycine max Merr.) plants were compared. Water use efficiency (WUE) (the ratio of rate of transpiration, E, to net rate of photosynthesis, A(n)) of well-watered wheat plants was improved slightly by strobilurin fungicides, but was reduced in water-stressed plants, so there is limited scope for using strobilurins to improve the water status of crops grown under conditions of drought. The different strobilurin fungicides had similar effects on plant physiology but differed in persistence and potency. When applied to whole plants using a spray gun, they reduced the conductance of water through the epidermis (stomatal and cuticular transpiration), g(sw), of leaves. Concomitantly, leaves of treated plants had a lower rate of transpiration, E, a lower intercellular carbon dioxide concentration, c(i), and a lower net rate of photosynthesis, A(n), compared with leaves of control plants or plants treated with the triazole. The mechanism for the photosynthetic effects is not known, but it is hypothesised that they are caused either by strobilurin fungicides acting directly on ATP production in guard cell mitochondria or by stomata responding to strobilurin-induced changes in mesophyll photosynthesis. The latter may be important since, for leaves of soya plants, the chlorophyll fluorescence parameter F(v)/F(m) (an indication of the potential quantum efficiency of PSII photochemistry) was reduced by strobilurin fungicides. It is likely that the response of stomata to strobilurin fungicides is complex, and further research is required to elucidate the different biochemical pathways involved. Copyright (c) 2007 Society of Chemical Industry.

  6. Evolution of Grain Yield and its Components Relationships in Bread Wheat Genotypes under Full Irrigation and Terminal Water Stress Conditions Using Multivariate Statistical Analysis

    Directory of Open Access Journals (Sweden)

    S Mohammadi

    2014-07-01

    Full Text Available To study relationships between effective traits on wheat grain yield, the varieties Zarrin and Alvand, and some promising lines i.e. C-81-4, C-81-10, C-81-14 and C-82-12 were investigated at three sowing dates including 10 October, 1 November and 21 November. The experiment was carried out using strip plot in RCBD with three replications under two different water conditions including full-irrigation and terminal water stress at Miyandoab Agricultural Research Station in 2005-06 and 2006-07 cropping seasons. The results showed that under both full irrigation and terminal water stress conditions, grain yield had positive and significant correlation with days to heading, days to maturity, plant height, number of spikes/m2 and 1000 grain weight. Stepwise regression analysis revealed that 83 percent of yield variation under non-stressed conditions could be determined by days to maturity and number of spikes/m2 (R2 = 83% whereas these traits explained 87% of yield variation under stress conditions (R2= 87%. Path analysis indicated that number of spikes/m2 and days to maturity had the greatest positive direct and indirect effect on grain yield, under both conditions. The results of factor analysis under non-stressed condition showed that three factors explained 77% of total variation; these factors were called grain yield components, grain characteristics and plant phonology. Under non-stressed condition two factors (that were called grain yield and phenology, and plant morphology explained 88% of total variation. Cluster analysis through ward method, classified days to maturity and number of spikes/m2 in the same cluster where the grain yield was put under both conditions. It was concluded that under different sowing dates, selection based on days to maturity and number spikes/m2 could indirectly led to higher yield under both normal and water stress conditions.

  7. Remote detection of water stress conditions via a diurnal photochemical reflectance index (PRI) improves yield prediction in rainfed wheat

    Science.gov (United States)

    Magney, T. S.; Vierling, L. A.; Eitel, J.

    2014-12-01

    Employing remotely sensed techniques to quantify the existence and magnitude of midday photosynthetic downregulation using the photochemical reflectance index (PRI) may reveal new information about plant responses to abiotic stressors in space and time. However, the interpretation and application of the PRI can be confounded because of its sensitivity to several variables changing at the diurnal (e.g., irradiation, shadow fraction) and seasonal (e.g., leaf area, chlorophyll and carotene pigment concentrations, irradiation) time scales. We explored different techniques to correct the PRI for variations in canopy structure and relative chlorophyll content (ChlR) using highly temporally resolved (frequency = five minutes) in-situ radiometric measurements of PRI and the Normalized Difference Vegetation Index (NDVI) over eight soft white spring wheat (Triticum aestivum L.)field plots under varying nitrogen and soil water conditions over two seasons. Our results suggest that the influence of seasonal variation in canopy ChlR and LAI on the diurnally measured PRI (PRIdiurnal) can be minimized using simple correction techniques, therefore improving the strength of PRI as a tool to quantify abiotic stressors such as daily changes in soil volumetric water content (SVWC), and vapor pressure deficit (VPD). PRIdiurnal responded strongly to available nitrogen, and linearly tracked seasonal changes in SVWC, VPD, and stomatal conductance (gc). Utilizing the PRI as an indicator of stress, yield predictions significantly over greenness indices such as the NDVI. This study provides insight towards the future interpretation and scaling of PRI to quantify rapid changes in photosynthesis, and as an indicator of plant stress.

  8. 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

  9. Dry matter yield, carbon isotope discrimination and nitrogen uptake in silicon and/ or potassium fed chickpea and barley plants grown under water and non-water stress conditions

    International Nuclear Information System (INIS)

    Kurd Ali, F.; Al-Chammaa, M.; Mouasess, A.

    2012-09-01

    higher spike's N yield. Solely added Si or in combination with K significantly reduced leave's Δ 13 C reflecting their bifacial effects on water use efficiency (WUE), particularly in plants grown under well watering regime. This result indicated that Si might be involved in saving water loss through reducing transpiration rate and facilitating water uptake; consequently, increasing its use efficiency. Although the rising of soil humidity generally increased fertilizer nitrogen uptake (Ndff) and its use efficiency (%NUE) in barley plants, applications of K or Si fertilizers to water stressed plants resulted in significant increments of these parameters as compared with the control. Our results highlight that Si or K is not only involved in amelioration of growth of barley plants, but can also improve nitrogen uptake and fertilizer nitrogen use efficiency particularly under water deficit conditions. (authors)

  10. Evaluation of Biofertilizer “Myco-green” on Water Relation and Efficiency of Potato Minituber Production in Drought Stress Condition

    Directory of Open Access Journals (Sweden)

    K. Parvizi

    2016-02-01

    Full Text Available Introduction Today biological fertilizers are suitable substitutes for chemical manure. Hence they can improve soil fertility in sustainable agriculture system (Mandal et al, 2007. Moreover, in some composition they are accompanied with plant growth promoting rhizibacteria (PGPR, namely Pseudomonas and some Bacillus species. These bacteria can improve growth rate of the plants by some physiological aspects namely, cidrophore acid production, increasing endogenously phytohormone and helping more phosphor absorption and fixation of biological nitrogen (Tilack et al., 2005. The symbiosis of mycorrhiza with plants confers numerous benefits to host plants including improved plant growth and mineral nutrient absorption, tolerance to diseases and stresses such as drought, temperature fluctuation, metal toxicity, salinity and other adverse conditions (Fortin et al, 2002. Ryan et al, (2003 and Smith and Reed, (2008.Mycorrhizal plants are capable of absorbing more water in lower potential of water as compared with non-mycorrhizal plants (Sanchez and Blanco, 2001. Micro propagation of potato by micro and mini tubers have been established for improving multiplication rate and possibility of reserving some more stock plants as germplasm. Multiplication of the minitubers already have been accompanied by lower establishment that causes low vigor and performance of the plant. This experiment was performedto study the effect of biological manure accompanied with mycorrhiza and plant growth promoting rhizobacteria on water relationship and vigor of the plantlets derived from minituber in water stress condition. Material and Methods Myco-green is produced by Peat grow company in Malaysia and has been spreading in floriculture, seed beds, vegetable crops, seedling plant of oil palm and many other plants. The experiment was performedatthe University of International Technology Mara Sarawak (UITM. As first step, soil bed composition was combined with peat and perlite

  11. Modulating the phenology and yield of camelina sativa L. by varying sowing dates under water deficit stress conditions

    Directory of Open Access Journals (Sweden)

    Ejaz Ahmad Waraich

    2017-05-01

    Full Text Available Camelina (Camelina sativa L. an oilseed crop has emerged as a potential source for biofuels and bio-products. Camelina is an economic crop due to its less requirements of agronomic inputs as compared to other oilseed crops. However, it is direly required to evaluate the adaptability of camelina and characterize its production potential. Therefore, a pot experiment was carried out in rain out shelter at the Department of Agronomy, University of Agriculture, Faisalabad, Pakistan to optimize appropriate sowing date with respect to growth and yield potential of different genotypes of camelina under drought stress. Completely randomized design with factorial arrangements was adopted. Three sowing dates with the difference of 10 days (November 13 th, 23rd and December 03rd, two water regimes (100% FC and 60% FC and two camlena genotypes (611 and 618 were used in this experiment. Results indicated that camelina growth and yield related traits were significantly influenced by difference in sowing dates and water regimes. Maximum leaf area index (LAI, crop growth rate (CGR, leaf area duration (LAD, net assimilation rate (NAR and yield related traits were recorded with early sowing (13th November which was followed by sowing on 23rd November and least values of these variables were recorded in late sowing (December 03rd. Plants grown under water deficit conditions (60% FC showed the decreased values of LAI, CGR, LAD, NAR and yield related attributes as compared to normally irrigated plants (100% FC. However, the response of genotypes of camelina 611 and 618 remained statistically similar to each other.

  12. Determining the Threshold Value of Basil Yield Reduction and Evaluation of Water Uptake Models under Salinity Stress Condition

    Directory of Open Access Journals (Sweden)

    M. Sarai Tabrizi

    2016-10-01

    Full Text Available Introduction: Several mathematical models are being used for assessing the plant response to the salinity of the root zone. The salinity of the soil and water resources is a major challenge for agricultural sector in Iran. Several mathematical models have been developed for plant responses to the salinity stress. However, these models are often applicable in particular conditions. The objectives of this study were to evaluate the threshold value of Basil yield reduction, modeling Basil response to salinity and to evaluate the effectiveness of available mathematical models for the yield estimation of the Basil . Materials and Methods: The extensive experiments were conducted with 13 natural saline water treatments including 1.2, 1.8, 2, 2.2, 2.5, 2.8, 3, 3.5, 4, 5, 6, 8, and 10 dSm-1. Water salinity treatments were prepared by mixing Shoor River water with fresh water. In order to quantify the salinity effect on Basil yield, seven mathematical models including Maas and Hoffman (1977, van Genuchten and Hoffman (1984, Dirksen and Augustijn (1988, and Homaee et al., (2002 were used. One of the relatively recent methods for soil water content measurements is theta probes instrument. Theta probes instrument consists of four probes with 60 mm long and 3 mm diameter, a water proof container (probe structure, and a cable that links input and output signals to the data logger display. The advantages that have been attributed to this method are high precision and direct and rapid measurements in the field and greenhouse. The range of measurements is not limited like tensiometer and is from saturation to wilting point. In this study, Theta probes instrument was calibrated by weighing method for exact irrigation scheduling. Relative transpiration was calculated using daily soil water content changes. A coarse sand layer with 2 centimeters thick was used to decrease evaporation from the surface soil of the pots. Quantity comparison of the used models was done

  13. Pelletization of seeds of Raphanus sativus L. cv. Redondo Gigante with graphite for germination under water stress conditions

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    Nobel Penteado Freitas

    2000-01-01

    Full Text Available The effect of water stress on germination of radish seeds is dependent on the presence of light. The effect of pelletization of radish seeds with powdered graphite on the tolerance to water stress under light was analysed. White light and far-red lights were filtered by graphite increasing slightly the tolerance of pelleted seeds to water stress of -0.77MPa. Although red light also inhibited seed germination the graphite had no effect. We propose the pelletization of seeds of Raphanus sativus, at least in cv redondo gigante with graphite as a pratice before planting to increase the tolerance to water stress.O efeito do estresse hídrico é dependente da presença de luz em sementes de rabanete. O efeito da peletização com grafite em pó foi analisado. Luz branca e vermelho-extremo são filtradas pelo grafite aumentando parcialmente a tolerância ao estresse hídrico de -0,77MPa em sementes peletizadas. Embora a luz vermelha também iniba a germinação em condições de estresse a peletização não teve efeito. Nós propomos a peletização de sementes de Raphanus saivus L. cv. redondo gigante como uma prática antes do plantio para aumentar a tolerância ao estresse hídrico.

  14. Effects of leaf movement on leaf temperature, transpiration and radiation interception in soybean under water stress conditions

    International Nuclear Information System (INIS)

    Isoda, A.; Wang, P.

    2001-01-01

    Varietal differences in leaf movement were examined in terms of radiation interception, leaf temperature and transpiration under water stressed conditions. Five cultivars (Qindou 7232, Gaofei 16, Dongnong 87 - 138, 8285 - 8 and 8874) were grown in a concrete frame field in Xinjiang, China. Irrigation treatments (irrigation and no irrigation) were made from the flowering to the pod filling stage. A leaflet in the uppermost layer of the canopy was restrained horizontally. Leaf temperatures, transpiration rate (stem sap flow rate of the main stem per unit leaf area) and intercepted radiation of each leaflet were measured. There were greater varietal differences in leaf movement, leaf temperature and transpiration rate. Leaf temperature seemed to be adjusted by leaf movement and transpiration. The extent to which is adjusted by leaf movement and transpiration differed among the cultivars; leaf temperature was influenced mainly by leaf movement for Gaofei 16 and Dongnong 87 - 138, mainly by transpiration for Qindou 7232 and 8874, and by both for 8285 - 8. Intercepted radiation in the upper two layers of the canopy (20 cm from the uppermost) was greater in the irrigated plot, although the mean values of total leaflets of the irrigated plot were not different as compared to the non-irrigated plot. Although paraheliotropic leaf movement decreased radiation interception, it offers some possibilities for the improvement in radiation penetration within a dense canopy. Cumulated amount of transpiration during a day was compared between the restrained-leaf and the non-leaf-restrained plants in 8874. Paraheliotropic leaf movement reduced water loss by 23% in the irrigated and 71% in the non-irrigated plots

  15. Effects of water restriction following feeding on nutrient digestibilities, milk yield and composition and blood hormones in lactating Holstein cows under heat stress conditions

    Directory of Open Access Journals (Sweden)

    Jalil Ghassemi Nejad

    2015-08-01

    Full Text Available The effects of water restriction following feeding under heat stress conditions on nutrient digestibilities, milk yield and composition and some blood hormones in lactating Holstein cows were evaluated. The design was completely randomized with 30 high producing lactating Holstein cows (80.8±40.5 DIM which were assigned to two treatment groups (15 cows per treatment. Treatments were free access to water (FAW and 2 h water restriction (2hWR following feeding. Average temperature-humidity index (THI in the farm was over 80 throughout the experiment which defines heat stress conditions. Neutral detergent fibre, organic matter and ether extract digestibilities increased by water restriction (P0.05. Water intake was recorded daily during the digestibility period and was not different between FAW and 2hWR group (P>0.05. Fat corrected milk was higher in 2hWR group than FAW group (P0.05. Somatic cell counts were greater in 2hWR than FAW group (P0.05. Blood prolactin and growth hormone were higher in 2hWR group than the FAW group (P<0.05. It is concluded that water restriction for 2 hours following feeding improved nutrient digestibility of some dietary components and increased milk fat percentage in lactating Holstein cows under heat stress conditions.

  16. Transcriptome Profiling of the Potato (Solanum tuberosum L.) Plant under Drought Stress and Water-Stimulus Conditions.

    Science.gov (United States)

    Gong, Lei; Zhang, Hongxia; Gan, Xiaoyan; Zhang, Li; Chen, Yuchao; Nie, Fengjie; Shi, Lei; Li, Miao; Guo, Zhiqian; Zhang, Guohui; Song, Yuxia

    2015-01-01

    Drought stress can seriously affect tuberization, yield and quality of potato plant. However, the precise molecular mechanisms governing potato stolon's response to drought stress and water supply are not very well understood. In this work, a potato (Solanum tuberosum L.) variant, Ningshu 4, was subjected to severe drought stress treatment (DT) and re-watering treatment (RWT) at tuber bulking stage. Strand-specific cDNA libraries of stolon materials were constructed for paired-end transcriptome sequencing analyses and differentially expressed gene (DEG) examination. In comparison to untreated-control (CT) plants, 3189 and 1797 DEGs were identified in DT and RWT plants and 4154 solely expressed DEGs were screened out from these two comparison groups. Interestingly, 263 genes showed opposite expression patterns in DT and RWT plants. Among them, genes homologous to Protein Phosphatase 2C (PP2C), Aspartic protease in guard cell 1 (ASPG1), auxin-responsive protein, Arabidopsis pseudo response regualtor 2 (APRR2), GA stimulated transcripts in Arabidopsis 6 (GASA6), Calmodulin-like protein 19 (CML19), abscisic acid 8'-hydroxylases and calcium-transporting ATPase, et al. were related with drought-stress and water stimulus response. Sixteen DEGs involved in starch synthesis, accumulation and tuber formation exhibited significantly different expression upon re-watering. In addition, 1630, 1527 and 1596 transcription factor encoding genes were detected in CT, DT and RWT. DEGs of ERF, bHLH, MYB, NAC, WRKY, C2H2, bZIP and HD-ZIP families accounted for 50% in three comparison groups, respectively. Furthermore, characteristics of 565 gene ontology (GO) and 108 Kyoto Encyclopedia of Genes and Genomes pathways (KEGG) were analyzed with the 4154 DEGs. All these results suggest that the drought- and water-stimulus response could be implemented by the regulated expression of metabolic pathway DEGs, and these genes were involved in the endogenous hormone biosynthesis and signal

  17. Transcriptome Profiling of the Potato (Solanum tuberosum L. Plant under Drought Stress and Water-Stimulus Conditions.

    Directory of Open Access Journals (Sweden)

    Lei Gong

    Full Text Available Drought stress can seriously affect tuberization, yield and quality of potato plant. However, the precise molecular mechanisms governing potato stolon's response to drought stress and water supply are not very well understood. In this work, a potato (Solanum tuberosum L. variant, Ningshu 4, was subjected to severe drought stress treatment (DT and re-watering treatment (RWT at tuber bulking stage. Strand-specific cDNA libraries of stolon materials were constructed for paired-end transcriptome sequencing analyses and differentially expressed gene (DEG examination. In comparison to untreated-control (CT plants, 3189 and 1797 DEGs were identified in DT and RWT plants and 4154 solely expressed DEGs were screened out from these two comparison groups. Interestingly, 263 genes showed opposite expression patterns in DT and RWT plants. Among them, genes homologous to Protein Phosphatase 2C (PP2C, Aspartic protease in guard cell 1 (ASPG1, auxin-responsive protein, Arabidopsis pseudo response regualtor 2 (APRR2, GA stimulated transcripts in Arabidopsis 6 (GASA6, Calmodulin-like protein 19 (CML19, abscisic acid 8'-hydroxylases and calcium-transporting ATPase, et al. were related with drought-stress and water stimulus response. Sixteen DEGs involved in starch synthesis, accumulation and tuber formation exhibited significantly different expression upon re-watering. In addition, 1630, 1527 and 1596 transcription factor encoding genes were detected in CT, DT and RWT. DEGs of ERF, bHLH, MYB, NAC, WRKY, C2H2, bZIP and HD-ZIP families accounted for 50% in three comparison groups, respectively. Furthermore, characteristics of 565 gene ontology (GO and 108 Kyoto Encyclopedia of Genes and Genomes pathways (KEGG were analyzed with the 4154 DEGs. All these results suggest that the drought- and water-stimulus response could be implemented by the regulated expression of metabolic pathway DEGs, and these genes were involved in the endogenous hormone biosynthesis and signal

  18. 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:.

  19. 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.

  20. 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

  1. Effect of Chemical and Biological Phosphorus on Antioxidant Enzymes Activity and Some Biochemical Traits of Spring Safflower (Carthamus tinctorius L. under Water Deficit Stress Conditions

    Directory of Open Access Journals (Sweden)

    S. Heshmati

    2016-05-01

    Full Text Available To study the effects of biological and chemical phosphorus on antioxidant enzyme activity in safflower under water deficit conditions, an experiment was conducted in 2012 at the Research Field of the Faculty of Agriculture, Shahed University, Tehran, Iran. The experimental design was a split-factorial with three replicates. The main factor was the three levels of irrigation treatment: full irrigation (irrigation up to 50% soil moisture depletion relative to field capacity, water stress in the vegetative and flowering stages (irrigation up to 75% soil moisture depletion relative to field capacity. The sub-factor was the six treatments resulting from three levels of phosphate chemical fertilizer (0, 50, and 100 kg ha-1 Triple Super Phosphate, each at two levels of Barvar-2 bio-fertilizer (with and without inoculation with Barvar-2. According to the results of our experiment, antioxidant enzyme activity is affected by high levels of chemical phosphorus when there is no inoculation with biofertilizer (Barvar 2 under water stress in the vegetative and flowering stages. The results showed that inoculation with Barvar 2 in the absence of added chemical phosphorus increases the catalase activity and soluble protein concentration under drought stress in the vegetative and flowering stages. Also, using chemical phosphorus followed by Barvar 2 led to increase in the polyphenol oxidase activity and superoxide dismutase activity under these conditions. Inoculation with Barvar 2 in the absence of added chemical phosphorus significantly decreased the amount of malondialdehyde under stress condition at the flowering stage. It was demonstrated that inoculation with a biological fertilizer (Barvar 2 followed by application of a chemical phosphorus fertilizer under drought conditions could decrease the detrimental effects of drought stress on spring safflower.

  2. In-silico analysis of water and carbon relations under stress conditions. A multi-scale perspective centered on fruit

    Directory of Open Access Journals (Sweden)

    Valentina eBALDAZZI

    2013-12-01

    Full Text Available Fruit development, from its early stages, is the result of a complex network of interacting processes, at different scales. These include cell division, cell expansion but also nutrient transports from the plant and exchanges with the environment. In the presence of nutrients limitation, in particular, the plant reacts as whole, by modifying its architecture, metabolism and reproductive strategy, determining the resources available for fruits development, which in turn affects the overall source-sink balance of the system.Here we present an integrated model of tomato that explicitly accounts for early developmental changes (from cell division to harvest, and use it to investigate the impact of water deficit and carbon limitation on nutrient fluxes and fruit growth, in both dry and fresh mass. Variability in fruit response is analyzed at two different scales: among trusses, at the plant level and within the cells population, at the fruit scale. Results show that the effect of stress on individual cells strongly depends on their age, size and uptake capabilities and that the timing of stress application, together with the fruit position on the plant, is crucial to determine the final phenotypic outcome. Water deficit and carbon depletion impacted either source size, source activity or sink strength with contrasted effects on fruit growth. An important prediction of the model is the major role of symplasmic transport of carbon in early stage of fruit development, as a catalyst of cells and fruit growth.

  3. The effect of plant growth-promoting rhizobacteria on asparagus seedlings and germinating seeds subjected to water stress under greenhouse conditions.

    Science.gov (United States)

    Liddycoat, Scott M; Greenberg, Bruce M; Wolyn, David J

    2009-04-01

    Plant growth-promoting rhizobacteria (PGPR) can have positive effects on vigour and productivity, especially under stress conditions. In asparagus (Asparagus officinalis L.) field culture, seeds are planted in high-density nurseries, and 1-year-old crowns are transplanted to production fields. Performance can be negatively affected by water stress, transplant shock, and disease pressure on wounded roots. PGPR inoculation has the potential to alleviate some of the stresses incurred in the production system. In this study, the effects of PGPR (Pseudomonas spp.) treatment were determined on 3-week-old greenhouse-grown seedlings and germinating seeds of 2 asparagus cultivars. The pots were irrigated to a predetermined level that resulted in optimum growth or the plants were subjected to drought or flooding stress for 8 weeks. The cultivars responded differently to PGPR: single inoculations of seedlings enhanced growth of 'Guelph Millennium' under optimum conditions and 'Jersey Giant' seedlings under drought stress. Seed inoculations with PGPR resulted in a positive response only for 'Guelph Millennium', for which both single or multiple inoculations enhanced plant growth under drought stress.

  4. [The ultrastructure of Leydig cells under the influence of drinking mineral water and electromagnetic radiation under the stress conditions in the rats].

    Science.gov (United States)

    Geniatulina, M S; Korolev, Yu N; Nikulina, L A

    The objective of the present study was elucidate the peculiar features of low-intensity electromagnetic radiation (LI EMR) and mineral water (MW) on the ultrastructure of rat Leydig cells under conditions of immobilization stress. The experiments were carried out on outbred male rats with the use of electron microscopy. It has been demonstrated that the prophylactic consumption of drinking sulfate-containing mineral water and the application low-intensity electromagnetic radiation (with the flow power density of 1 mcW/cm2 and frequency around 1,000 Hz) or the combination of these two modalities under conditions of immobilization stress reduced the degree of ultrastructural derangement in the rat Leydig cells and stimulated the development of regenerative processes. In the cases of the single-factor impact, drinking mineral water exerted more pronounced action than low-intensity electromagnetic radiation on mitochondrial regeneration. In case of the simultaneous application of the two factors their protective action on the Leydig cells was much more conspicuous than that of either of them applied alone. It is concluded that drinking sulfate-containing mineral water in combination with the application of low-intensity electromagnetic radiation enhances resistance of the rat Leydig cells to stress.

  5. Effect of Drought Stress on Water Use Efficiency and Root Dry Weight of Wheat (Triticum aesativum L. and Rye (Secale cereale L. in Competition Conditions

    Directory of Open Access Journals (Sweden)

    F Golestani Far

    2017-10-01

    Full Text Available Introduction Deficiency of water during the plant growth is one of the main factors which reduce the crops production around the world. Drought stress is one of the most important tensions that may occur around the low rainfall, high temperature and wind blowing environments. Plant response to this stress depends on the stage of plant growth and drought intensity. Weeds are unwanted and harmful plants with disturbance in agricultural practices which make increase the cost of crop production and reduce the crop yields. Rye (Secale cereal L. is one of the most important weeds at wheat fields in Iran (Baghestani and Atri, 2003. Low expectations, allelopathic effects and similarity of life cycle and morphology, caused increasing of rye density in winter wheat fields. Water use efficiency (WUE as an important physiological characteristic indicates the ability of plants to water stress. WUE may be affected by climatic and soil or plant factors. In plant communities, competition is one of most important physiological topics (Evans et al, 2003. At Inter-specific competition, weeds interfere to absorbing of light, water and nutrients through the adjacency with crop and so affect the growth and yield of crops. Weeds often compete with crops for soil water and reduce the accessibility of water. Competition between weeds and crops decrease the soil moisture and cause water stress which might decrease the weeds and crops growth. When the supply of water is limited, water drainage overlap areas in soil profile could be occurred relatively fast at early of in the crop life cycle. Materials and Methods In order to study the effects of drought stress on water use efficiency and root dry weight of wheat (Triticum aesativum L. and rye (Secale cereale L. in competition conditions, a pot experiment was conducted in the greenhouse of Agriculture Faculty , University of Birjand in 2012. The experiment was arranged as factorial based on completely randomized design

  6. The influence of ppb levels of chloride impurities on the stress corrosion crack growth behaviour of low-alloy steels under simulated boiling water reactor conditions

    International Nuclear Information System (INIS)

    Seifert, H.P.; Ritter, S.

    2016-01-01

    Highlights: • Chloride effects on SCC crack growth in RPV steels under boiling water reactor conditions. • ppb-levels of chloride may result in fast SCC in normal water chemistry environment. • Much higher chloride tolerance for SCC in hydrogen water chemistry environment. • Potential long-term (memory) effects after severe and prolonged temporary chloride transients. - Abstract: The effect of chloride on the stress corrosion crack (SCC) growth behaviour in low-alloy reactor pressure vessel steels was evaluated under simulated boiling water reactor conditions. In normal water chemistry environment, ppb-levels of chloride may result in fast SCC after rather short incubation periods of few hours. After moderate and short-term chloride transients, the SCC crack growth rates return to the same very low high-purity water values within few 100 h. Potential long-term (memory) effects on SCC crack growth cannot be excluded after severe and prolonged chloride transients. The chloride tolerance for SCC in hydrogen water chemistry environment is much higher.

  7. The Effect of Vermicompost and Mycorrhizal Inoculation on Grain Yield and some Physiological Characteristics of Soybean (Glycine max L. under Water Stress Condition

    Directory of Open Access Journals (Sweden)

    Elham Jahangiri nia

    2017-08-01

    Full Text Available Introduction Moisture limitation is considered as one of the important limiting factors in soybean growth. Drought stress affects different aspects of soybean growth through making anatomical, physiological and biochemical changes (Tarumingkeng & Coto, 2003. Under dry tension condition, there will be a disturbance in transmitting nutrients, but some useful soil fungi such as mycorrhiza improve production of crops under stress through forming colonies in the root and boosting water and nutrient absorption (Al-Karaki et al., 2004. Using vermicompost in sustainable agriculture strengthens support and activities of beneficial soil microorganisms (such as mycorrhizal fungi and phosphate solubilizing microorganisms in order to provide nutrients required by plants like nitrogen, phosphorus and soluble potassium as well as improving the growth and performance of the crops (Arancon et al., 2004. Materials and methods In order to investigate the effects of vermicompost and mycorrhiza fertilizers on grain yield and some physiological characteristics of soybean under water stress condition an experiment was conducted at Agricultural Research Center of Khorramabad during 2013. The field experiment was carried out based on a randomized complete blocks design arranged in split-plot with four replications. The experiment treatments including irrigation in three levels (after 60, 120 and 180 mm evaporation from pan class A pan, nutrient management in six levels (non-use of vermicompost and mycorhiza fertilizer, inoculated with mycorrhiza fertilizer, consumption of 5 and 10 t.ha-1 vermicompost, consumption of 5 and 10 t.ha-1 vermicompost with mycorrhiza were respectively as the main plots and sub. In current study, RWC, LAI, SPAD were measured during 59 days after planting at the beginning of podding of the control treatment. The temperature of plant leaves were measured by the thermometer (model TM-958 LUTRON infrared Thermometers. To analyze the growth of

  8. Effect of water soluble vitamins on Zn transport of Caco-2 cells and their implications under oxidative stress conditions.

    Science.gov (United States)

    Tupe, Rashmi Santosh; Agte, Vaishali Vilas

    2010-02-01

    The role of different water soluble vitamins in Zn metabolism beyond intestinal Zn absorption is poorly explored. Using Caco-2 cells, effects of different vitamins on intestinal Zn transport and their implications under oxidative stress (OS) were investigated. Cells were apically treated with Zn (25 muM) and vitamins (Folic acid (FA), Nicotinic acid (NA), Ascorbic acid (AA), riboflavin, thiamine, pyridoxine) for 60 min. The effect of most promising vitamins on zinc transport, antioxidant enzymes (Catalase, Glutathione peroxidase, and superoxide dismutase), and intracellular OS status (ROS generation and mitochondrial transmembrane potential) were investigated. OS was generated by tert-butyl hydro peroxide and results for each vitamin were compared with respective Zn containing controls with and without OS. Without OS, Zn transport was slightly enhanced in presence of NA, while it was significantly reduced by thiamine, riboflavin, and pyridoxine. Under OS, NA significantly (P vitamins. With Zn + FA + OS, enzyme activities decreased maximally, with twofold increase in 2',7'-dichlorofluorescin diacetate (DCF-DA) (P < 0.01) and lowering of rhodamine fluorescence (P < 0.05). In Zn + AA + OS, DCF-DA fluorescence increased (P < 0.05) but with NA, cellular enzymes, and antioxidant profile were improved. Results for the first time demonstrate advantageous effects of NA and deleterious consequences of FA with no effect by AA on Zn transport, especially under OS. These observed changes in the transport of Zn seem to have an impact on OS markers.

  9. Effect of Silicon application on Morpho-physiological Characteristics, Grain Yield and Nutrient Content of Bread Wheat under Water Stress Conditions

    Directory of Open Access Journals (Sweden)

    A. Karmollachaab

    2015-03-01

    Full Text Available In order to investigate the effect of silicon application on some physiological characteristics, yield and yield components, and grain mineral contents of bread wheat (Triticum aestivum under water stress condition, an experiment was conducted in Ramin Agriculture and Natural Resources University, Khuzestan, in 2012. The experiment was arranged in split-plots design in RCBD (Completely Randomized Blocks Design with three replications. Treatments consisted of drought stress (irrigation after 25, 50 and 75% depletion of Available Water Content in main plots and silicon (0, 10, 20 and 30 Kg Si ha-1 arranged in sub-plots. Results showed that the effect of drought stress was significant on most traits and led to the increase of electrolyte leakage (EL, cuticular wax, leaf and grain silicon content and grain nitrogen content. But drought led to negative impacts on grain yield and its components, and leaf potassium content, i.e. moderate and severe stresses reduced yield by 17% and 38% compared to control, respectively. Effect of silicon application was significant on all traits except for spike per square meter. Silicon had the greatest impact on EL and led to 35% decrease in this trait. Also, silicon led to increase in leaf and grain silicon contents and grain K content and grain yield and yield components, when applied at 30 kg ha-1. Generally, application of 30 kg ha-1 of silicon led to 6 and 14% increases of grain yield at the presence of moderate and severe drought stresses, respectively. Thus, given the abundance of silicon it can be used as an ameliorating element for planting bread wheat in drought-prone conditions.

  10. Utility of remote sensing-based surface energy balance models to track water stress in rain-fed switchgrass under dry and wet conditions

    Science.gov (United States)

    Bhattarai, Nishan; Wagle, Pradeep; Gowda, Prasanna H.; Kakani, Vijaya G.

    2017-11-01

    The ability of remote sensing-based surface energy balance (SEB) models to track water stress in rain-fed switchgrass (Panicum virgatum L.) has not been explored yet. In this paper, the theoretical framework of crop water stress index (CWSI; 0 = extremely wet or no water stress condition and 1 = extremely dry or no transpiration) was utilized to estimate CWSI in rain-fed switchgrass using Landsat-derived evapotranspiration (ET) from five remote sensing based single-source SEB models, namely Surface Energy Balance Algorithm for Land (SEBAL), Mapping ET with Internalized Calibration (METRIC), Surface Energy Balance System (SEBS), Simplified Surface Energy Balance Index (S-SEBI), and Operational Simplified Surface Energy Balance (SSEBop). CWSI estimates from the five SEB models and a simple regression model that used normalized difference vegetation index (NDVI), near-surface temperature difference, and measured soil moisture (SM) as covariates were compared with those derived from eddy covariance measured ET (CWSIEC) for the 32 Landsat image acquisition dates during the 2011 (dry) and 2013 (wet) growing seasons. Results indicate that most SEB models can predict CWSI reasonably well. For example, the root mean square error (RMSE) ranged from 0.14 (SEBAL) to 0.29 (SSEBop) and the coefficient of determination (R2) ranged from 0.25 (SSEBop) to 0.72 (SEBAL), justifying the added complexity in CWSI modeling as compared to results from the simple regression model (R2 = 0.55, RMSE = 0.16). All SEB models underestimated CWSI in the dry year but the estimates from SEBAL and S-SEBI were within 7% of the mean CWSIEC and explained over 60% of variations in CWSIEC. In the wet year, S-SEBI mostly overestimated CWSI (around 28%), while estimates from METRIC, SEBAL, SEBS, and SSEBop were within 8% of the mean CWSIEC. Overall, SEBAL was the most robust model under all conditions followed by METRIC, whose performance was slightly worse and better than SEBAL in dry and wet years

  11. Effects of Satureja khuzistanica essential oils in drinking water on mortality, production performance, water intake, and organ weights in broiler chickens reared under heat stress condition.

    Science.gov (United States)

    Khosravinia, H

    2015-11-01

    An experiment was conducted to examine the effects on mortality, production performance, water intake (WI), and organ weight of Satureja khuzistanica essential oil (SkEO) using 720 1-day-old Arian broiler chicks in a 42-day trial. Experimental treatments were addition of 0 (control(-)), 200, 300, 400, and 500 mg/L SkEO or 500 mg/L polysorbate 80 (control(+)) into drinking water. The birds were kept under natural ambient temperatures 4 to 6 °C above standard recommendation from days 22 to 42 of age. Addition of SkEO into drinking water at 200 and 500 mg/L decreased weight gain (P  0.05). Supplementation of drinking water with 200, 300, 400, and 500 mg/L SkEO resulted in a 0.47, 4.40, 8.60, and 12.93% decrease in WI, respectively, from days 1 to 42 of age. The calculated European broiler index was greater for the birds received 400 mg/L of SkEO in their drinking water compared with that of the other birds (P water for heat-stressed broiler chickens improves economic efficiency possibly by promoting digestion process, creating miniscule improvement in FCR and lowered mortality rate.

  12. Thermal–mechanical stress analysis of pressurized water reactor pressure vessel with/without a preexisting crack under grid load following conditions

    Energy Technology Data Exchange (ETDEWEB)

    Mohanty, Subhasish, E-mail: smohanty@anl.gov; Soppet, William K.; Majumdar, Saurin; Natesan, Krishnamurti

    2016-12-15

    Highlights: • Use of intermittent renewable-energy source in power grid is becoming a trend. • Gird load-following can leads to variable power demand from Nuclear power plant. • Reactor components can be stressed differently under gird load-following mode. • Estimation of stress–strain state under grid load-following condition is essential. - Abstract: In this paper, we present thermal–mechanical stress analysis of a pressurized water reactor pressure vessel and its hot-leg and cold-leg nozzles. Results are presented from thermal and thermal–mechanical stress analysis under reactor heat-up, cool-down, and grid load-following conditions. Analysis results are given with and without the presence of preexisting crack in the reactor nozzle (axial crack in hot leg nozzle). From the model results it is found that the stress–strain states are significantly higher in case of presence of crack than without crack. The stress–strain state under grid load following condition are more realistic compared to the stress–strain state estimated assuming simplified transients.

  13. Thermal–mechanical stress analysis of pressurized water reactor pressure vessel with/without a preexisting crack under grid load following conditions

    International Nuclear Information System (INIS)

    Mohanty, Subhasish; Soppet, William K.; Majumdar, Saurin; Natesan, Krishnamurti

    2016-01-01

    Highlights: • Use of intermittent renewable-energy source in power grid is becoming a trend. • Gird load-following can leads to variable power demand from Nuclear power plant. • Reactor components can be stressed differently under gird load-following mode. • Estimation of stress–strain state under grid load-following condition is essential. - Abstract: In this paper, we present thermal–mechanical stress analysis of a pressurized water reactor pressure vessel and its hot-leg and cold-leg nozzles. Results are presented from thermal and thermal–mechanical stress analysis under reactor heat-up, cool-down, and grid load-following conditions. Analysis results are given with and without the presence of preexisting crack in the reactor nozzle (axial crack in hot leg nozzle). From the model results it is found that the stress–strain states are significantly higher in case of presence of crack than without crack. The stress–strain state under grid load following condition are more realistic compared to the stress–strain state estimated assuming simplified transients.

  14. 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.

  15. Genotypic Correlation and Path Analysis of Some Traits related to Oil Yield and Grain Yield in Canola (Brassica napus L. under Non-stress and Water Deficit Stress Conditions

    Directory of Open Access Journals (Sweden)

    A Ismaili

    2017-03-01

    Full Text Available Introduction Obtaining varieties with acceptable yield and tolerant to different arid and semi-arid climate condition of Iran is an important goal in canola breeding programs. Selection of genotypes base on one or more traits without regarding to correlation between them, could biases the expected results. Therefore, identifying of genetic correlation among traits especially in environmental stress condition is very important. The use of genotypic correlation helps evaluating the magnitude and direction of associations between characters facilitating the application of indirect selection, because genetic changes in a given trait may change other traits, leading to faster and larger genetic gains in plant breeding programs. Therefore, the selection for another trait may result in indirect response in the low heritable trait, provided the following conditions are satisfied: the genetic correlation between them is substantial, and the heritability of the secondary trait is greater than that of the primary trait. The purpose of this study was estimating the total genotypic variability, genotypic correlations, and path analysis among some important traits for selection criteria for improving seed and oil yield in canola under water deficit stress condition. Materials and Methods For evaluation of genetic correlation among traits and identifying important affecting traits on grain yield and oil yield in canola genotypes, an experiment was conducted based on a randomized complete blocks design with three replications in two different conditions of water deficit (stress and non-stress. Different traits were measured including seed yield, 1000-seed weight, number of seeds per pod, number of pods per plant, silique length, oil content, days to maturity, protein content, plant height and water use efficiency. Genotypic and phenotypic correlation coefficients were calculated for ten characters during growing seasons. The genotypic correlation coefficients

  16. Utility of remote sensing-based surface energy balance models to track water stress in rain-fed switchgrass under dry and wet conditions

    Science.gov (United States)

    The ability of remote sensing-based surface energy balance (SEB) models to track water stress in rain-fed switchgrass has not been explored yet. In this paper, the theoretical framework of crop water stress index (CWSI) was utilized to estimate CWSI in rain-fed switchgrass (Panicum virgatum L.) usin...

  17. Effective stress coefficient for uniaxial strain condition

    DEFF Research Database (Denmark)

    Alam, M.M.; Fabricius, I.L.

    2012-01-01

    one dimensional rock mechanical deformation. We further investigated the effect of boundary condition on the stress dependency of effective stress coefficient and discussed its application in reservoir study. As stress field in the reservoirs are most unlikely to be hydrostatic, effective stress...... determined under uniaxial strain condition will be more relevant in reservoir studies. Copyright 2012 ARMA, American Rock Mechanics Association....

  18. Cracks propagation by stress corrosion cracking in conditions of Boiling Water Reactor (BWR); Propagacion de grietas por corrosion bajo esfuerzo en condiciones de reactor de agua hirviente (BWR)

    Energy Technology Data Exchange (ETDEWEB)

    Fuentes C, P

    2003-07-01

    This work presents the results of the assays carried out in the Laboratory of Hot Cells of the National Institute of Nuclear Research (ININ) to a type test tube Compact Tension (CT), built in steel austenitic stainless type 304L, simulating those conditions those that it operates a Boiling Water Reactor (BWR), at temperature 288 C and pressure of 8 MPa, to determine the speed to which the cracks spread in this material that is of the one that different components of a reactor are made, among those that it highlights the reactor core vessel. The application of the Hydrogen Chemistry of the Water is presented (HWC) that is one alternative to diminish the corrosion effect low stress in the component, this is gets controlling the quantity of oxygen and of hydrogen as well as the conductivity of the water. The rehearsal is made following the principles of the Mechanics of Elastic Lineal Fracture (LEFM) that considers a crack of defined size with little plastic deformation in the tip of this; the measurement of crack advance is continued with the technique of potential drop of direct current of alternating signal, this is contained inside the standard Astm E-647 (Method of Test Standard for the Measurement of Speed of Growth of Crack by fatigue) that is the one that indicates us as carrying out this test. The specifications that should complete the test tubes that are rehearsed as for their dimensions, it forms, finish and determination of mechanical properties (tenacity to the fracture mainly) they are contained inside the norm Astm E-399, the one which it is also based on the principles of the fracture mechanics. The obtained results were part of a database to be compared with those of other rehearsals under different conditions, Normal Chemistry of the Water (NWC) and it dilutes with high content of O{sub 2}; to determine the conditions that slow more the phenomena of stress corrosion cracking, as well as the effectiveness of the used chemistry and of the method of

  19. Effect of dietary vitamin E on broiler meat qualities, color, water-holding capacity and shear force value, under heat stress conditions.

    Science.gov (United States)

    Hashizawa, Yoshinori; Kubota, Masatoshi; Kadowaki, Motoni; Fujimura, Shinobu

    2013-11-01

    This study was conducted to evaluate the effect of dietary vitamin E (VE) on broiler meat quality, especially focused on PSE (pale color, soft and exudative), under chronic heat stress (HS) conditions. Twenty-eight-day-old female Ross broilers were kept in independent cages with a controlled temperature of 24°C (normal temperature: NT) or 30°C (high temperature: HT). The NT chickens were fed basal feed. The HT chickens were fed basal feed (HT) or VE (200 mg/kg) added feed (HT + E). Broilers were weighed and slaughtered at 38 days old. The breast muscle was removed immediately and then the samples were used for determination of meat color, pH, water holding capacity (WHC) and shear force value (SFV). Body weight gain and feed intake were significantly decreased in the HT and HT + E groups compared to the NT group. VE supplementation did not affect the growth performance. Chronic HS at 30°C for 10 days may cause deterioration of meat quality such as PSE. The effects of chronic HS on meat quality were most significant in the toughness of broiler breast meat. Supplementation of VE in broiler feed would be effective to prevent the extent of PSE on broiler meat by chronic HS. © 2013 Japanese Society of Animal Science.

  20. Identification of new SSR markers linked to leaf chlorophyll content, flag leaf senescence and cell membrane stability traits in wheat under water stressed condition.

    Science.gov (United States)

    Barakat, Mohamed N; Saleh, Mohamed; Al-Doss, Abdullah A; Moustafa, Khaled A; Elshafei, Adel A; Al-Qurainy, Fahed H

    2015-03-01

    Segregating F4 families from the cross between drought sensitive (Yecora Rojo) and drought tolerant (Pavon 76) genotypes were made to identify SSR markers linked to leaf chlorophyll content, flag leaf senescence and cell membrane stability traits in wheat (Triticum aestivum L.) under water-stressed condition and to map quantitative trait locus (QTL) for the three physiological traits. The parents and 150 F4 families were evaluated phenotypically for drought tolerance using two irrigation treatments (2500 and 7500 m3/ha). Using 400 SSR primers tested for polymorphism in testing parental and F4 families genotypes, the results revealed that QTL for leaf chlorophyll content, flag leaf senescence and cell membrane stability traits were associated with 12, 5 and 12 SSR markers, respectively and explained phenotypic variation ranged from 6 to 42%. The SSR markers for physiological traits had genetic distances ranged from 12.5 to 25.5 cM. These SSR markers can be further used in breeding programs for drought tolerance in wheat.

  1. 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.

  2. 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

  3. 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.

  4. The grapevine root-specific aquaporin VvPIP2;4N controls root hydraulic conductance and leaf gas exchange under well-watered conditions but not under water stress.

    Science.gov (United States)

    Perrone, Irene; Gambino, Giorgio; Chitarra, Walter; Vitali, Marco; Pagliarani, Chiara; Riccomagno, Nadia; Balestrini, Raffaella; Kaldenhoff, Ralf; Uehlein, Norbert; Gribaudo, Ivana; Schubert, Andrea; Lovisolo, Claudio

    2012-10-01

    We functionally characterized the grape (Vitis vinifera) VvPIP2;4N (for Plasma membrane Intrinsic Protein) aquaporin gene. Expression of VvPIP2;4N in Xenopus laevis oocytes increased their swelling rate 54-fold. Northern blot and quantitative reverse transcription-polymerase chain reaction analyses showed that VvPIP2;4N is the most expressed PIP2 gene in root. In situ hybridization confirmed root localization in the cortical parenchyma and close to the endodermis. We then constitutively overexpressed VvPIP2;4N in grape 'Brachetto', and in the resulting transgenic plants we analyzed (1) the expression of endogenous and transgenic VvPIP2;4N and of four other aquaporins, (2) whole-plant, root, and leaf ecophysiological parameters, and (3) leaf abscisic acid content. Expression of transgenic VvPIP2;4N inhibited neither the expression of the endogenous gene nor that of other PIP aquaporins in both root and leaf. Under well-watered conditions, transgenic plants showed higher stomatal conductance, gas exchange, and shoot growth. The expression level of VvPIP2;4N (endogenous + transgene) was inversely correlated to root hydraulic resistance. The leaf component of total plant hydraulic resistance was low and unaffected by overexpression of VvPIP2;4N. Upon water stress, the overexpression of VvPIP2;4N induced a surge in leaf abscisic acid content and a decrease in stomatal conductance and leaf gas exchange. Our results show that aquaporin-mediated modifications of root hydraulics play a substantial role in the regulation of water flow in well-watered grapevine plants, while they have a minor role upon drought, probably because other signals, such as abscisic acid, take over the control of water flow.

  5. [The combined action of drinking mineral water and low-intensity electromagnetic radiation under the immobilization stress conditions (an experimental study)].

    Science.gov (United States)

    Korolev, Yu N; Bobrovnitsky, I P; Geniatulina, M S; Mikhailik, L V; Nikulina, L A; Bobkova, A S; Yakovlev, M Yu

    2015-01-01

    The present study carried out on white male rats in experiments with the use of biochemical, radioimmunological, and electron- microscopic methods. It was shown that the combined treatment with potable mineral water (MV) and low-intensity electromagnetic radiation (LIEMR) of ultrahigh frequency (power density less than 1 pW/cm2, the frequency about 1000 MHz) facilitated the activation of metabolic and intracellular regenerative processes in the liver and testes. One of the advantages of the combined application of MV and LIEMR over the single-factor treatment manifested itself as the weakening of stress reactions, the increase in the frequency of the plastic processes, and the more harmonious development of different forms of intracellular regeneration. The results of the study provide a deeper insight ino the mechanisms underlying the combined actions of drinking mineral water and low-intensity electromagnetic radiation; also, they justify the application of these factors for the protection of the reproductive system and the entire body from stress-induced disorders.

  6. Genetic control and combining ability of flag leaf area and relative water content traits of bread wheat cultivars under drought stress condition

    Directory of Open Access Journals (Sweden)

    Golparvar Ahmad Reza

    2013-01-01

    Full Text Available In order to compare mode of inheritance, combining ability, heterosis and gene action in genetic control of traits flag leaf area, relative water content and grain filling rate of bread wheat under drought stress, a study was conducted on 8 cultivars using of Griffing’s method2 in fixed model. Mean square of general combining ability was significant also for all traits and mean square of specific combining ability was significant also for all traits except relative water content of leaf which show importance of both additive and dominant effects of genes in heredity of these traits under stress. GCA to SCA mean square ratio was significant for none of traits. Results of this study showed that non additive effects of genes were more important than additive effect for all traits. According to results we can understand that genetic improvement of mentioned traits will have low genetic efficiency by selection from the best crosses of early generations. Then it is better to delay selection until advanced generations and increase in heritability of these traits.

  7. Stable symbiotic nitrogen fixation under water-deficit field conditions by a stress-tolerant alfalfa microsymbiont and its complete genome sequence.

    Science.gov (United States)

    Jozefkowicz, Cintia; Brambilla, Silvina; Frare, Romina; Stritzler, Margarita; Piccinetti, Carlos; Puente, Mariana; Berini, Carolina Andrea; Pérez, Pedro Reyes; Soto, Gabriela; Ayub, Nicolás

    2017-12-10

    We here characterized the stress-tolerant alfalfa microsymbiont Sinorhizobium meliloti B401. B401-treated plants showed high nitrogen fixation rates under humid and semiarid environments. The production of glycine betaine in isolated bacteroids positively correlated with low precipitation levels, suggesting that this compound acts as a critical osmoprotectant under field conditions. Genome analysis revealed that strain B401 contains alternative pathways for the biosynthesis and uptake of glycine betaine and its precursors. Such genomic information will offer substantial insight into the environmental physiology of this biotechnologically valuable nitrogen-fixing bacterium. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Strain rate and temperature effects on the stress corrosion cracking of Inconel 600 steam generator tubing in the primary water conditions

    International Nuclear Information System (INIS)

    Kim, U.C.; van Rooyen, D.

    1985-01-01

    A single heat of Inconel Alloy 600 was examined in this work, using slow strain rate tests (SSRT) in simulated primary water at temperatures of 325 0 -345 0 -365 0 C. The best measure of stress corrosion cracking (SCC) was percent SCC present on the fracture surface. Strain rate did not seem to affect crack growth rate significantly, but there is some question about the accuracy of calculating these values in the absence of a direct indication of when a crack initiates. Demarcation was determined between domains of temperature/strain rate where SCC either did, or did not, occur. Slower extension rates were needed to produce SCC as the temperature was lowered. 10 figs

  9. 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

  10. Identification of Water Usage Efficiency for Corn(Zea mays L.Lines Irrigated with Drip Irrigation Under Green House Conditions asPer Plant Water Stress Index Evaluations

    Directory of Open Access Journals (Sweden)

    Ali Beyhan UÇAK

    2017-02-01

    Full Text Available The present study was conducted as a greenhouse study under Çukurova conditions during the years2011-2012. Two different dent corn lines (5A2-B and 22K were used as the plant material of the experiments. Crop water stress index (CWSI values determined through leaf canopy temperature measurements performed ahead of irrigations were used to find outwater use efficiencies. Experiments were conducted in randomized blocks-split plots experimental design with three replications. Drip irrigation was used for irrigations and two different irrigation programs were created as of I100(supplying 100% of depleted water in every seven days and I75(applying 75% of depleted water. The amount of irrigation water applied for in the interaction of I100irrigation and corn lines (5A2-B and22K in the first and second year were respectively varied between 253.0-274.0and between 238.0-261.0mm, seasonal plant water consumptions varied between 294.0-305.0and between 284.6-302.6 mm, kernel yields varied between 2950.0-2990.0 and between 3130.0-3186.0kgha-1. With regard to (in the interaction irrigation treatments xcorn lines, the lowest and the highest CWSI values were observed in the interaction full irrigation (I100 and of the line 22K as 0.22 and in deficit irrigation treatment (I75 of the line 5A2-B as 0.41in the first year; in full irrigation treatment (I100 of the line 22K as 0.20 and in deficit irrigation treatment (I75 of the line 5A2-B as 0.36. The greatest and the lowest chlorophyll contents (in the interaction irrigation treatments x corn lines were respectively observed in I100treatment of the line 22K as 58.3 spad and in I75treatment of the line 5A2-Bas 50.9 spad in the first year; in I100treatment of the line 22K as 59.1 SPAD and in I75treatment of the line 5A2-B as 55.1 spad. While the effects of irrigation treatments on average dry matter contents of the lines were not found to be significant, significant differences were observed in water use efficiency

  11. Emotional memory consolidation under lower versus higher stress conditions

    Directory of Open Access Journals (Sweden)

    Inna eKogan

    2010-12-01

    Full Text Available An exposure to stress can enhance memory for emotionally arousing experiences. The phenomenon is suggested to be amygdala-dependent and in accordance with that view the amygdala was found to modulate mnemonic processes in other brain regions. Previously, we illustrated increased amygdala activation and reduced activation of CA1 following spatial learning under high versus low emotionality conditions. When spatial learning was followed by reversal training interference, impaired retention was detected only under high emotionality conditions. Here we further evaluate the potential implications of the difference in the level of amygdala activation on the quality of the memory formed under these stress conditions. We attempted to affect spatial memory consolidation under low or high stress conditions by either introducing a foot shock interference following massed training in the water maze; by manipulating the threshold for acquisition employing either brief (3 trials or full (12 trials training sessions; or by employing a spaced training (over three days rather than massed training protocol. The current findings reveal that under heightened emotionality, the process of consolidation seems to become less effective and more vulnerable to interference; however, when memory consolidation is not interrupted, retention is improved. These differential effects might underlie the complex interactions of stress, and, particularly, of traumatic stress with memory formation processes.

  12. 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

  13. Seasonal variability of the parameters of the Ball-Berry model of stomatal conductance in maize (Zea mays L.) and sunflower (Helianthus annuus L.) under well-watered and water-stressed conditions.

    Science.gov (United States)

    Miner, Grace L; Bauerle, William L

    2017-09-01

    The Ball-Berry (BB) model of stomatal conductance (g s ) is frequently coupled with a model of assimilation to estimate water and carbon exchanges in plant canopies. The empirical slope (m) and 'residual' g s (g 0 ) parameters of the BB model influence transpiration estimates, but the time-intensive nature of measurement limits species-specific data on seasonal and stress responses. We measured m and g 0 seasonally and under different water availability for maize and sunflower. The statistical method used to estimate parameters impacted values nominally when inter-plant variability was low, but had substantial impact with larger inter-plant variability. Values for maize (m = 4.53 ± 0.65; g 0  = 0.017 ± 0.016 mol m -2 s -1 ) were 40% higher than other published values. In maize, we found no seasonal changes in m or g 0 , supporting the use of constant seasonal values, but water stress reduced both parameters. In sunflower, inter-plant variability of m and g 0 was large (m = 8.84 ± 3.77; g 0  = 0.354 ± 0.226 mol m -2 s -1 ), presenting a challenge to clear interpretation of seasonal and water stress responses - m values were stable seasonally, even as g 0 values trended downward, and m values trended downward with water stress while g 0 values declined substantially. © 2017 John Wiley & Sons Ltd.

  14. 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 ...

  15. 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.

  16. 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.

  17. 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.

  18. Bioactive compounds in potatoes: Accumulation under drought stress conditions

    Directory of Open Access Journals (Sweden)

    Christina B. Wegener

    2015-03-01

    Full Text Available Background: Potato (Solanum tuberosum is a valuable source of bioactive compounds. Besides starch, crude fibre, amino acids (AAS, vitamins and minerals, the tubers contain diverse phenolic compounds. These phenolics and AAS confer anti-oxidant protection against reactiveoxygen species, tissue damage, and diseases like atherosclerosis, renal failure, diabetes mellitus,and cancer. Climate change and drought stress may become a major risk for crop production worldwide, resulting in reduced access for those who depend on the nutritional value of this staple crop. Objective: The aim of this study is to determine the effect of drought stress on water, lipid soluble antioxidants, anthocyanins (Ac, soluble phenols, proteins, free AAS, peroxidase (POD and lipid acyl hydrolase activity (LAH in tuber tissue. Methods: The study was carried out on three potato genotypes comprising one yellow-fleshed cultivar and two purple breeding clones. The plants were grown in pots (from April to September in a glasshouse with sufficient water supply and under drought stress conditions. After harvest, the tubers of both variants were analysed for antioxidants measured as ascorbic acid (ACE and Trolox equivalent (TXE using a photo-chemiluminescent method. Amounts of anthocyanins (Ac, soluble phenols, proteins, as well as POD and LAH activities were analysed using a UV photometer. Finally, free AAS were measured by HPLC. Results: The results revealed that drought stress significantly reduces tuber yield, but has no significant effect on antioxidants, Ac, soluble phenols and POD. Drought stress significantly increased the levels of soluble protein (P < 0.0001 and LAH (P < 0.001. Also, total amounts of free AAS were higher in the drought stressed tubers (+34.2%, on average than in the tubers grown with a sufficient water supply. Above all, proline was elevated due to drought stress.

  19. System for stress corrosion conditions tests on PWR reactors

    International Nuclear Information System (INIS)

    Castro, Andre Cesar de Jesus

    2007-01-01

    The study of environmentally assisted cracking (EAC) involves the consideration and evaluation of the inherent compatibility between a material and the environment under conditions of either applied or residual stress. EAC is a critical problem because equipment, components and structure are subject to the influence of mechanical stress, water environment of different composition, temperature and different material history. Testing for resistance to EAC is one of the most effective ways to determine the interrelationships among this variables on the process of EAC. Up to now, several experimental techniques have been developed worldwide, which address different aspects of environmental caused damage. Constant loading of CT specimens test is a typical example of test, which is used for the estimation of parameters of stress corrosion cracking. To assess the initiation stages and kinetics of crack growth, the testing facility should allow active loading of specimens in the environment that is close to the actual operation conditions of assessed component. This paper presents a testing facility for stress corrosion cracking to be installed at CDTN, which was designed and developed at CDTN. The facility is used to carry out constant load tests under simulated PWR environment, where temperature, water pressure and chemistry are controlled, which are considered the most important factors in SCC. Also, the equipment operational conditions, its applications, and restrictions are presented. The system was developed to operate at temperature until 380 degree C and pressure until 180 bar. It consists in a autoclave stuck at a mechanical system, responsible of producing load , a water treatment station, and a data acquisition system. This testing facility allows the evaluation of cracking progress, especially at PWR reactor. (author) operational conditions. (author)

  20. 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

  1. Psychological stress associated with cardiogenetic conditions.

    Science.gov (United States)

    Hidayatallah, Nadia; Silverstein, Louise B; Stolerman, Marina; McDonald, Thomas; Walsh, Christine A; Paljevic, Esma; Cohen, Lilian L; Marion, Robert W; Wasserman, David; Hreyo, Sarah; Dolan, Siobhan M

    2014-09-01

    Genetic testing now makes it possible to identify specific mutations that may lead to life-threatening cardiac arrhythmias. This article presents data from a qualitative research study that explored the subjective experiences of individuals and families with cardiogenetic conditions. We focus on describing patients' experiences of psychological stresses associated with having a cardiogenetic condition, illustrating the importance of integrating psychological and medical care. This integration of care is particularly important as personalized genomic medicine continues to evolve and the implications of genetic testing have a profound effect on individuals and families. The researchers interviewed 50 participants from 32 families. The research team used a systematic, grounded theory procedure to code and analyze interview and focus group transcripts, incorporating multiple coders at several stages of the data analysis process. Three major themes emerged: a bereavement trajectory associated with sudden death in the absence of prior symptoms; high anxiety about transmitting a genetic mutation; and resilience reflected in positive lifestyle changes and participation in support groups. This article identifies patient perspectives on personalized genomic medicine in cardiogenetics that can improve clinical care, including: specialized bereavement counseling; improving education about cardiogenetic conditions for medical professionals; parent guidelines for discussing cardiogenetic conditions with their children; information about support groups; and the routine inclusion of clinical psychologists in interdisciplinary treatment teams. Given recent advances in technology and decreasing costs, whole-genome sequencing is likely to become common practice in the near future. Therefore, these recommendations are likely to be relevant for other genetic conditions, as well as the entire field of personalized genomic medicine.

  2. 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.

  3. Triaxial Wetting Test on Rockfill Materials under Stress Combination Conditions of Spherical Stress p and Deviatoric Stress q

    Directory of Open Access Journals (Sweden)

    Yan-yi Zhang

    2018-01-01

    Full Text Available A GCTS medium-sized triaxial apparatus is used to conduct a single-line method wetting test on three kinds of rockfill materials of different mother rocks such as mixture of sandstone and slate, and dolomite and granite, and the test stress conditions is the combination of spherical stress p and deviatoric stress q. The test results show that (1 for wetting shear strain, the effects of spherical stress p and deviatoric stress q are equivalent, and wetting shear strain and deviatoric stress q show the power function relationship preferably. (2 For wetting volumetric strain, the effect of deviatoric stress q can be neglected because it is extremely insignificant, and spherical stress p is the main influencing factor and shows the power function relationship preferably. (3 The wetting strains decrease significantly with the increase in initial water content and sample density generally, but the excessively high dry density will increase the wetting deformation. Also, the wetting strains will decrease with the increase in the saturated uniaxial compressive strength and average softening coefficient of the mother rock. Based on the test results, a wetting strain model is proposed for rockfill materials. The verification results indicate that the model satisfactorily reflects the development law of wetting deformation.

  4. 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

  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. 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

  9. Plant cover, soil temperature, freeze, water stress, and evapotranspiration conditions. [Lower Rio Grande Valley Test Site: Weslaco, Texas; Falco Reservoir and the Gulf of Mexico

    Science.gov (United States)

    Wiegand, C. L.; Nixon, P. R.; Gausman, H. W.; Namken, L. N.; Leamer, R. W.; Richardson, A. J. (Principal Investigator)

    1980-01-01

    The author has identified the following significant results. HCMM day/night coverage 12 hours apart cannot be obtained at 26 deg N latitude; nor have any pairs 36 hours apart been obtained. A day-IR scene and a night scene for two different dates were analyzed. A profile across the test site for the same latitude shows that the two profiles are near mirror images of each other over land surfaces and that the temperature of two large water bodies, Falcon Reservoir and the Gulf of Mexico, are nearly identical on two dates. During the time interval between overpasses, the vegetative cover remained static due to winter dormancy. The data suggest that day/night temperature differences measured weeks apart may yield meaningful information about the contrast between daytime maximum and nighttime minimum temperatures for a given site.

  10. Varietal improvement of irrigated rice under minimal water conditions

    International Nuclear Information System (INIS)

    Abdul Rahim Harun; Marziah Mahmood; Sobri Hussein

    2010-01-01

    Varietal improvement of irrigated rice under minimal water condition is a research project under Program Research of Sustainable Production of High Yielding Irrigated Rice under Minimal Water Input (IRPA- 01-01-03-0000/ PR0068/ 0504). Several agencies were involved in this project such as Malaysian Nuclear Agency (MNA), Malaysian Agricultural Research and Development Institute (MARDI), Universiti Putra Malaysia (UPM) and Ministry of Agriculture (MOA). The project started in early 2004 with approved IRPA fund of RM 275,000.00 for 3 years. The main objective of the project is to generate superior genotypes for minimal water requirement through induced mutation techniques. A cultivated rice Oryza sativa cv MR219 treated with gamma radiation at 300 and 400 Gray were used in the experiment. Two hundred gm M2 seeds from each dose were screened under minimal water stress in greenhouse at Mardi Seberang Perai. Five hundred panicles with good filled grains were selected for paddy field screening with simulate precise water stress regime. Thirty eight potential lines with required adaptive traits were selected in M3. After several series of selection, 12 promising mutant line were observed tolerance to minimal water stress where two promising mutant lines designated as MR219-4 and MR219-9 were selected for further testing under several stress environments. (author)

  11. 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 ...

  12. Physical-chemistry aspects of water in steam turbines associated with material stress and electrochemical assessment of the AISI 403 to simulate real condition

    Energy Technology Data Exchange (ETDEWEB)

    Pacheco, D S; Franco, C V; Godinho, J F; Frech, W A; Sonai, G G [Univ. Federal de Santa Catarina, Florianopolis (Brazil); Torres, L A.M.; Ellwanger, A R.F. [Tractebel Energia, Capivari de Baixo (Brazil)

    2009-07-01

    This study described a methodology developed to prevent the occurrence of corrosion failure in steam turbines. The methodology was developed after the failure of a turbine blade at a plant in Brazil. Deposits were collected from various locations along the turbine blade path and analyzed. A turbine deposit collector and simulator was installed to determine the concentrations of steam impurities. Samples were collected from the low pressure turbine at the crossover point and from the polishing station and analyzed using inductive coupled plasma-mass spectrometry (ICP-MS) in order to determine if sodium levels exceeded 3 ppb. Filters were weighed in order to determine the accumulation of impurities. A 3-electrode system was used to determine the influence of chloride ions. The design of the system's condensate polisher beds was modified in order to improve condensate effluent conductivity. The condensate treatment procedure lowered the concentrations of salt impurities and established a monitoring methodology for water and steam used at the plant. It was concluded that the methodology can be used to to reduce inspection intervals and increase system reliability. 10 refs., 1 tab., 7 figs.

  13. 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

  14. 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.

  15. Modified stress intensity factor as a crack growth parameter applicable under large scale yielding conditions

    International Nuclear Information System (INIS)

    Yasuoka, Tetsuo; Mizutani, Yoshihiro; Todoroki, Akira

    2014-01-01

    High-temperature water stress corrosion cracking has high tensile stress sensitivity, and its growth rate has been evaluated using the stress intensity factor, which is a linear fracture mechanics parameter. Stress corrosion cracking mainly occurs and propagates around welded metals or heat-affected zones. These regions have complex residual stress distributions and yield strength distributions because of input heat effects. The authors previously reported that the stress intensity factor becomes inapplicable when steep residual stress distributions or yield strength distributions occur along the crack propagation path, because small-scale yielding conditions deviate around those distributions. Here, when the stress intensity factor is modified by considering these distributions, the modified stress intensity factor may be used for crack growth evaluation for large-scale yielding. The authors previously proposed a modified stress intensity factor incorporating the stress distribution or yield strength distribution in front of the crack using the rate of change of stress intensity factor and yield strength. However, the applicable range of modified stress intensity factor for large-scale yielding was not clarified. In this study, the range was analytically investigated by comparison with the J-integral solution. A three-point bending specimen with parallel surface crack was adopted as the analytical model and the stress intensity factor, modified stress intensity factor and equivalent stress intensity factor derived from the J-integral were calculated and compared under large-scale yielding conditions. The modified stress intensity was closer to the equivalent stress intensity factor when compared with the stress intensity factor. If deviation from the J-integral solution is acceptable up to 2%, the modified stress intensity factor is applicable up to 30% of the J-integral limit, while the stress intensity factor is applicable up to 10%. These results showed that

  16. 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.

  17. 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.

  18. 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.

  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. 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.

  1. WATER CONDITIONING FOR FOOD INDUSTRY USES

    Directory of Open Access Journals (Sweden)

    RAISA NASTAS

    2011-03-01

    Full Text Available Water conditioning for food industry uses. Tap (drinkingwater from many localities of Moldova doesn’t always correspond to the “Sanitarystandards for drinking water quality” or to the requirements of the “Regulation fornon-alcoholic beverages”, requiring the need for additional purification/conditioning. This paper presents research regarding the removal/adsorption of themain pollutants in tap water (iron, manganese, aluminum, humic substances,trihalomethanes on supports of local carbon adsorbents made from vegetableproducts (stones of peach and plum, walnut shells. Experiments were performedin dynamic conditions in columns of carbon adsorbents. As work solutions wasused tap water where pollutants have been introduced in amounts equivalent to 3maximum allowable concentrations. Carbonaceous adsorbents used forremoval/adsorption of pollutants in dynamic conditions, reveal a capacity of up to1:400 volumes adsorbent: solution before breakthrough. Combined filter, utilizingactive carbons, was constructed and tested for conditioning of tap water forbeverage and food production. The results demonstrated efficient remove oforganic substances and heavy metals by filtering of about 700 volumes of waterper volume of filter.

  2. Electrochemical noise measurements under pressurized water reactor conditions

    International Nuclear Information System (INIS)

    Van Nieuwenhove, R.

    2000-01-01

    Electrochemical potential noise measurements on sensitized stainless steel pressure tubes under pressurized water reactor (PWR) conditions were performed for the first time. Very short potential spikes, believed to be associated to crack initiation events, were detected when stressing the sample above the yield strength and increased in magnitude until the sample broke. Sudden increases of plastic deformation, as induced by an increased tube pressure, resulted in slower, high-amplitude potential transients, often accompanied by a reduction in noise level

  3. 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.

  4. Characterizing drought stress and trait influence on maize yield under current and future conditions.

    Science.gov (United States)

    Harrison, Matthew T; Tardieu, François; Dong, Zhanshan; Messina, Carlos D; Hammer, Graeme L

    2014-03-01

    Global climate change is predicted to increase temperatures, alter geographical patterns of rainfall and increase the frequency of extreme climatic events. Such changes are likely to alter the timing and magnitude of drought stresses experienced by crops. This study used new developments in the classification of crop water stress to first characterize the typology and frequency of drought-stress patterns experienced by European maize crops and their associated distributions of grain yield, and second determine the influence of the breeding traits anthesis-silking synchrony, maturity and kernel number on yield in different drought-stress scenarios, under current and future climates. Under historical conditions, a low-stress scenario occurred most frequently (ca. 40%), and three other stress types exposing crops to late-season stresses each occurred in ca. 20% of cases. A key revelation shown was that the four patterns will also be the most dominant stress patterns under 2050 conditions. Future frequencies of low drought stress were reduced by ca. 15%, and those of severe water deficit during grain filling increased from 18% to 25%. Despite this, effects of elevated CO2 on crop growth moderated detrimental effects of climate change on yield. Increasing anthesis-silking synchrony had the greatest effect on yield in low drought-stress seasonal patterns, whereas earlier maturity had the greatest effect in crops exposed to severe early-terminal drought stress. Segregating drought-stress patterns into key groups allowed greater insight into the effects of trait perturbation on crop yield under different weather conditions. We demonstrate that for crops exposed to the same drought-stress pattern, trait perturbation under current climates will have a similar impact on yield as that expected in future, even though the frequencies of severe drought stress will increase in future. These results have important ramifications for breeding of maize and have implications for

  5. Transcriptome profiling of tobacco under water deficit conditions

    Directory of Open Access Journals (Sweden)

    Roel C. Rabara

    2015-09-01

    Full Text Available Drought is one of the limiting environmental factors that affect crop production. Understanding the molecular basis of how plants respond to this water deficit stress is key to developing drought tolerant crops. In this study we generated time course-based transcriptome profiles of tobacco plants under water deficit conditions using microarray technology. In this paper, we describe in detail the experimental procedures and analyses performed in our study. The data set we generated (available in the NCBI/GEO database under GSE67434 has been analysed to identify genes that are involved in the regulation of tobacco's responses to drought.

  6. 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

  7. Modeling heat stress under different environmental conditions.

    Science.gov (United States)

    Carabaño, M J; Logar, B; Bormann, J; Minet, J; Vanrobays, M-L; Díaz, C; Tychon, B; Gengler, N; Hammami, H

    2016-05-01

    Renewed interest in heat stress effects on livestock productivity derives from climate change, which is expected to increase temperatures and the frequency of extreme weather events. This study aimed at evaluating the effect of temperature and humidity on milk production in highly selected dairy cattle populations across 3 European regions differing in climate and production systems to detect differences and similarities that can be used to optimize heat stress (HS) effect modeling. Milk, fat, and protein test day data from official milk recording for 1999 to 2010 in 4 Holstein populations located in the Walloon Region of Belgium (BEL), Luxembourg (LUX), Slovenia (SLO), and southern Spain (SPA) were merged with temperature and humidity data provided by the state meteorological agencies. After merging, the number of test day records/cows per trait ranged from 686,726/49,655 in SLO to 1,982,047/136,746 in BEL. Values for the daily average and maximum temperature-humidity index (THIavg and THImax) ranges for THIavg/THImax were largest in SLO (22-74/28-84) and shortest in SPA (39-76/46-83). Change point techniques were used to determine comfort thresholds, which differed across traits and climatic regions. Milk yield showed an inverted U-shaped pattern of response across the THI scale with a HS threshold around 73 THImax units. For fat and protein, thresholds were lower than for milk yield and were shifted around 6 THI units toward larger values in SPA compared with the other countries. Fat showed lower HS thresholds than protein traits in all countries. The traditional broken line model was compared with quadratic and cubic fits of the pattern of response in production to increasing heat loads. A cubic polynomial model allowing for individual variation in patterns of response and THIavg as heat load measure showed the best statistical features. Higher/lower producing animals showed less/more persistent production (quantity and quality) across the THI scale. The

  8. Physiological basis of barley yield under near optimal and stress conditions

    Directory of Open Access Journals (Sweden)

    Pržulj Novo

    2004-01-01

    Full Text Available Average barley yield fall below its potential due to incidence of stresses. Water stress is the main environmental factor limiting yield. The component a priori more sensitive to most stresses is the amount of radiation absorbed. The effect of stresses influence on the total amount of radiation absorbed by barley crop during its vegetation and the photosynthetic efficiency of radiation conversion. Growth inhibition is accompanied by reductions in leaf and cell wall extensibility. Grain yield under drought conditions is source limited. Supply of assimilates to the developing inflorescence plays a critical role in establishing final grain number and grain size. Grain weight is negatively affected by drought, high temperature, and any other factors that may reduce grain filling duration and grain filling rate. Awns and glaucousness confer better performance of barley under drought stress conditions. Barley responds with an increased accumulation of a number of proteins when subjected to different stress inducing cell dehydration. Screening techniques that are able to identify desirable genotypes based on the evaluation of physiological traits related to stress evasion and stress resistance maybe useful in breeding barley for resistance to stress, particularly drought stress. Crop management and breeding can reduce the incidence of stress on yield. The effect of these practices is sustained by an understanding of their physiology. In this paper the physiological basis of the processes determining barley yield and the incidence of stresses on photosynthetic metabolism that determine grain yield of barley is discussed. .

  9. 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

  10. 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.

  11. Psychosocial working conditions and stress in UK social workers

    OpenAIRE

    Ravalier, J.M

    2018-01-01

    It is well documented that exposure to chronic negative working conditions leads to stress. This subsequently impacts sickness absence and attrition, making it a key consideration for policymakers and academics alike. This study therefore seeks to investigate the influence of psychosocial working conditions on stress and related outcomes: sickness presenteeism, job satisfaction, and turnover intentions in UK social workers (SWs). A cross-sectional survey was used, in addition to a single open...

  12. 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.

  13. 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.

  14. 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...

  15. Surface-Water Conditions in Georgia, Water Year 2005

    Science.gov (United States)

    Painter, Jaime A.; Landers, Mark N.

    2007-01-01

    INTRODUCTION The U.S. Geological Survey (USGS) Georgia Water Science Center-in cooperation with Federal, State, and local agencies-collected surface-water streamflow, water-quality, and ecological data during the 2005 Water Year (October 1, 2004-September 30, 2005). These data were compiled into layers of an interactive ArcReaderTM published map document (pmf). ArcReaderTM is a product of Environmental Systems Research Institute, Inc (ESRI?). Datasets represented on the interactive map are * continuous daily mean streamflow * continuous daily mean water levels * continuous daily total precipitation * continuous daily water quality (water temperature, specific conductance dissolved oxygen, pH, and turbidity) * noncontinuous peak streamflow * miscellaneous streamflow measurements * lake or reservoir elevation * periodic surface-water quality * periodic ecological data * historical continuous daily mean streamflow discontinued prior to the 2005 water year The map interface provides the ability to identify a station in spatial reference to the political boundaries of the State of Georgia and other features-such as major streams, major roads, and other collection stations. Each station is hyperlinked to a station summary showing seasonal and annual stream characteristics for the current year and for the period of record. For continuous discharge stations, the station summary includes a one page graphical summary page containing five graphs, a station map, and a photograph of the station. The graphs provide a quick overview of the current and period-of-record hydrologic conditions of the station by providing a daily mean discharge graph for the water year, monthly statistics graph for the water year and period of record, an annual mean streamflow graph for the period of record, an annual minimum 7-day average streamflow graph for the period of record, and an annual peak streamflow graph for the period of record. Additionally, data can be accessed through the layer's link

  16. Effective Stress Law in Unconventional Reservoirs under Different Boundary Conditions

    Science.gov (United States)

    Saurabh, S.; Harpalani, S.

    2017-12-01

    Unconventional reservoirs have attracted a great deal of research interest worldwide during the past two decades. Low permeability and specialized techniques required to exploit these resources present opportunities for improvement in both production rates and ultimate recovery. Understanding subsurface stress modifications and permeability evolution are valuable when evaluating the prospects of unconventional reservoirs. These reservoir properties are functions of effective stress. As a part of this study, effective stress law, specifically the variation of anisotropic Biot's coefficient under various boundary conditions believed to exist in gas reservoirs by different researchers, has been established. Pressure-dependent-permeability (PdK) experiments were carried out on San Juan coal under different boundary conditions, that is, uniaxial strain condition and constant volume condition. Stress and strain in the vertical and horizontal directions were monitored throughout the experiment. Data collected during the experiments was used to determine the Biot's coefficient in vertical and horizontal directions under these two boundary conditions, treating coal as transversely isotropic. The variation of Biot's coefficient was found to be well correlated with the variation in coal permeability. Based on the estimated values of Biot's coefficients, a theory of variation in its value is presented for other boundary conditions. The findings of the study shed light on the inherent behavior of Biot's coefficient under different reservoir boundary conditions. This knowledge can improve the modeling work requiring estimation of effective stress in reservoirs, such as, pressure-/stress- dependent permeability. At the same time, if the effective stresses are known with more certainty by other methods, it enables assessment of the unknown reservoir boundary conditions.

  17. 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.

  18. Evaluation of Grain Quality in Bread Wheat Recombinant Inbred Lines Under Drought Stress Conditions

    Directory of Open Access Journals (Sweden)

    H. Shahbazi

    2014-04-01

    Full Text Available To study drought stress effect on grain quality properties of wheat, an experiment was conductedusing 169 recombinant inbreed lines (RILS under water stress and non-stress condition and with two separated lattice designs. Grain yield, protein yield, protein content, volume of Zeleny sediment, grain hardness, water absorption, grain moisture content and grain dry matter were evaluated. Analysis of variance showed that there were significant differences among the lines for all traits. Moreover, comparison between two lines in two environmental conditions showed, the quality in bread wheat under drought stress conditions due to increment of protein yield is improved. Protein yield in both irrigation regimes has a significant and negative correlation with grain moisture and in the other hand, significant and positive correlation with the grain hardiness dry matter, Zeleny sedimentation and water intake in both conditions. The results showed that the identification of favorable quality characteristics in optimum and stressed conditions were possible and the lines with high grain quality can be used in breeding programs for improving of baking quality. Although some drought sensitive genotypes possessed a favorable baking quality but their grain yield was low.

  19. 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.

  20. EXPRESSION OF CALCIUM-DEPENDENT PROTEIN KINASE (CDPK GENES IN VITIS AMURENSIS UNDER ABIOTIC STRESS CONDITIONS

    Directory of Open Access Journals (Sweden)

    Dubrovina A.S.

    2012-08-01

    Full Text Available Abiotic stresses, such as extreme temperatures, soil salinity, or water deficit, are one of the major limiting factors of crop productivity worldwide. Examination of molecular and genetic mechanisms of abiotic stress tolerance in plants is of great interest to plant biologists. Calcium-dependent protein kinases (CDPKs, which are the most important Ca2+ sensors in plants, are known to play one of the key roles in plant adaptation to abiotic stress. CDPK is a multigene family of enzymes. Analysis of CDPK gene expression under various abiotic stress conditions would help identify those CDPKs that might play important roles in plant adaptation to abiotic stress. We focused on studying CDPK gene expression under osmotic, water deficit, and temperature stress conditions in a wild-growing grapevine Vitis amurensis Rurp., which is native to the Russian Far East and is known to possess high adaptive potential and high level of resistance against adverse environmental conditions. Healthy V. amurensis cuttings (excised young stems with one healthy leaf were used for the treatments. For the non-stress treatment, we placed the cuttings in distilled water for 12 h at room temperature. For the water-deficit stress, detached cuttings were laid on a paper towel for 12 h at room temperature. For osmotic stress treatments, the cuttings were placed in 0.4 М NaCl and 0.4 М mannitol solutions for 12 h at room temperature. To examine temperature stress tolerance, the V. amurensis cuttings were placed in a growth chamber at +10oC and +37oC for 12 h. The total expression of VaCDPK genes was examined by semiquantitative RT-PCR with degenerate primers designed to the CDPK kinase domain. The total level of CDPK gene expression increased under salt and decreased under low temperature stress conditions. We sequenced 300 clones of the amplified part of different CDPK transcripts obtained from the analyzed cDNA probes. Analysis of the cDNA sequences identified 8 different

  1. Tolerance of Mycorrhiza infected pistachio (Pistacia vera L.) seedling to drought stress under glasshouse conditions.

    Science.gov (United States)

    Abbaspour, H; Saeidi-Sar, S; Afshari, H; Abdel-Wahhab, M A

    2012-05-01

    The influence of Glomus etunicatum colonization on plant growth and drought tolerance of 3-month-old Pistacia vera seedlings in potted culture was studied in two different water treatments. The arbuscular mycorrhiza (AM) inoculation and plant growth (including plant shoot and root weight, leaf area, and total chlorophyll) were higher for well-watered than for water-stressed plants. The growth of AM-treated seedlings was higher than non-AM-treatment regardless of water status. P, K, Zn and Cu contents in AM-treated shoots were greater than those in non-AM shoots under well-watered conditions and drought stress. N and Ca content were higher under drought stress, while AM symbiosis did not affect the Mg content. The contents of soluble sugars, proteins, flavonoid and proline were higher in mycorrhizal than non-mycorrhizal-treated plants under the whole water regime. AM colonization increased the activities of peroxidase enzyme in treatments, but did not affect the catalase activity in shoots and roots under well-watered conditions and drought stress. We conclude that AM colonization improved the drought tolerance of P. vera seedlings by increasing the accumulation of osmotic adjustment compounds, nutritional and antioxidant enzyme activity. It appears that AM formation enhanced the drought tolerance of pistachio plants, which increased host biomass and plant growth. Copyright © 2012 Elsevier GmbH. All rights reserved.

  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. Emotional Memory Formation Under Lower Versus Higher Stress Conditions

    OpenAIRE

    Kogan, Inna; Richter-Levin, Gal

    2010-01-01

    An exposure to stress can enhance memory for emotionally arousing experiences. The phenomenon is suggested to be amygdala-dependent and in accordance with that view the amygdala was found to modulate mnemonic processes in other brain regions. Previously, we illustrated increased amygdala activation and reduced activation of CA1 following spatial learning under higher versus lower stress conditions. When spatial learning was followed by reversal training interference, impaired retention was de...

  4. 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.

  5. Enhancement of wind stress evaluation method under storm conditions

    Science.gov (United States)

    Chen, Yingjian; Yu, Xiping

    2016-12-01

    Wind stress is an important driving force for many meteorological and oceanographical processes. However, most of the existing methods for evaluation of the wind stress, including various bulk formulas in terms of the wind speed at a given height and formulas relating the roughness height of the sea surface with wind conditions, predict an ever-increasing tendency of the wind stress coefficient as the wind speed increases, which is inconsistent with the field observations under storm conditions. The wave boundary layer model, which is based on the momentum and energy conservation, has the advantage to take into account the physical details of the air-sea interaction process, but is still invalid under storm conditions without a modification. By including the energy dissipation due to the presence of sea spray, which is speculated to be an important aspect of the air-sea interaction under storm conditions, the wave boundary layer model is improved in this study. The improved model is employed to estimate the wind stress caused by an idealized tropical cyclone motion. The computational results show that the wind stress coefficient reaches its maximal value at a wind speed of about 40 m/s and decreases as the wind speed further increases. This is in fairly good agreement with the field data.

  6. 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

  7. WATER CONDITION IN CELLS OF CHLORELLA

    Directory of Open Access Journals (Sweden)

    I. V. Kuznetsova

    2015-01-01

    Full Text Available The water condition in cages of the paste of chlorella was investigated by the method of thermogravimetric analysis. With increasing heating rate endothermic effect corresponding to the dehydration process is shifted towards higher temperatures. Temperature intervals of chlorella dehydration are defined at rate of heating 2 К/min - 308-368 K, 5 К/min - 323-403 K, and 10 К/min - 348-403 K. Quantitative characteristics of kinetic unequal water in chlorella have been received for each step (∆, ∆Т, a mass fraction (w, energy of activation (Еа. This process is similar to the process of the dehydration in ion exchange membranes. The derived kinetic characteristics give the possibility to define an optimum temperature interval and rate of drying microalgae for the purpose of increase of periods of storage in the form of paste or a solid substance for the further use as the bioadditive. In addition the presence of three types of water chlorella in a cell set according to NMR with pulsed magnetic field gradient. Since free water is involved in biochemical, chemical and microbiological processes, it is desirable to remove during drying of the preparation. The resulting temperature range of 323-343 K (step 2 at a heating rate of 2 K / min corresponds to a temperature range of drying the chlorella in a production environment. It should be noted that the highest number of algae in a tightly-water (the last stage. Apparently, this is determined by a unique cell structure. Temperature ranges dehydration process are not clear and vary depending on the heating rate, which is fully in line with previous studies of thermal analysis for grains, vegetables and bakery products.

  8. 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...

  9. 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 ...

  10. Comment on 'Shang S. 2012. Calculating actual crop evapotranspiration under soil water stress conditions with appropriate numerical methods and time step. Hydrological Processes 26: 3338-3343. DOI: 10.1002/hyp.8405'

    Science.gov (United States)

    Yatheendradas, Soni; Narapusetty, Balachandrudu; Peters-Lidard, Christa; Funk, Christopher; Verdin, James

    2014-01-01

    A previous study analyzed errors in the numerical calculation of actual crop evapotranspiration (ET(sub a)) under soil water stress. Assuming no irrigation or precipitation, it constructed equations for ET(sub a) over limited soil-water ranges in a root zone drying out due to evapotranspiration. It then used a single crop-soil composite to provide recommendations about the appropriate usage of numerical methods under different values of the time step and the maximum crop evapotranspiration (ET(sub c)). This comment reformulates those ET(sub a) equations for applicability over the full range of soil water values, revealing a dependence of the relative error in numerical ET(sub a) on the initial soil water that was not seen in the previous study. It is shown that the recommendations based on a single crop-soil composite can be invalid for other crop-soil composites. Finally, a consideration of the numerical error in the time-cumulative value of ET(sub a) is discussed besides the existing consideration of that error over individual time steps as done in the previous study. This cumulative ET(sub a) is more relevant to the final crop yield.

  11. Physical robustness of canopy temperature models for crop heat stress simulation across environments and production conditions

    DEFF Research Database (Denmark)

    Webber, Heidi; White, Jeffrey W; Kimball, Bruce

    2018-01-01

    to simulate Tc. Model performance in predicting Tc was evaluated for two experiments in continental North America with various water, nitrogen and CO2 treatments. An empirical model fit to one dataset had the best performance, followed by the EBSC models. Stability conditions explained much of the differences...... between modeling approaches. More accurate simulation of heat stress will likely require use of energy balance approaches that consider atmospheric stability conditions....

  12. CENTRAL AMYGDALOID INVOLVEMENT IN NEUROENDOCRINE CORRELATES OF CONDITIONED STRESS RESPONSES

    NARCIS (Netherlands)

    ROOZENDAAL, B; KOOLHAAS, JM; BOHUS, B

    The purpose of this study was to examine the effects of bilateral electrolytic lesions of the central nucleus of the amygdala (CEA) in comparison with sham lesions on neuroendocrine responses during conditioned emotional stress in male Wistar rats. Lesions in the CEA, made either before or after the

  13. 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.

  14. Early growth response of six wheat varieties under artificial osmotic stress condition

    International Nuclear Information System (INIS)

    Khakwani, A.A.; Dennett, M.D.; Munir, M

    2011-01-01

    An experiment was carried out under laboratory conditions where seeds of six wheat varieties (Damani, Hashim-8, Gomal-8, DN-73, Zam-04 and Dera-98) were raised in Petri dishes and were either treated with distilled water (control) or 15% polyethylene glycol (PEG) 6000 solution. Seeds were treated with 15% PEG solution to establish an artificial osmotic stress condition (water stress) and observe its effect on germination percentage, coleoptile length, shoot and root length, fresh weight of shoot and root. A significant difference (P<0.05) was recorded between varietal and treatment means regarding all traits. Variety Hashim-8 gave maximum germination percentage (93.33%) whereas maximum coleoptile (1.78 cm) and shoot length (5.77 cm) was observed in variety DN-73 which was statistically at par with variety Hashim-8. Similarly, root length (3.63 g), fresh shoot (0.15 g) and root weight (0.12 g) was maximum in variety Dera-98 which was statistically at par with variety Hashim-8. A second experiment was carried out under glass house environment where plants were treated with non-stress (100% field capacity) and water stress (35% field capacity) treatments. Although total grain yield was significantly (P<0.05) reduced in all six wheat varieties when grown in water stress condition however Hashim-8 showed the lowest reduction (13%) while Zam-04 showed the highest (32%). The outcome of both experiments indicated that these varieties have great potential to incorporate with the existing commercial wheat varieties in order to obtain high yield in water stress regions. (author)

  15. Poor working conditions and work stress among Canadian sex workers.

    Science.gov (United States)

    Duff, P; Sou, J; Chapman, J; Dobrer, S; Braschel, M; Goldenberg, S; Shannon, K

    2017-10-01

    While sex work is often considered the world's oldest profession, there remains a dearth of research on work stress among sex workers (SWs) in occupational health epidemiological literature. A better understanding of the drivers of work stress among SWs is needed to inform sex work policy, workplace models and standards. To examine the factors that influence work stress among SWs in Metro Vancouver. Analyses drew from a longitudinal cohort of SWs, known as An Evaluation of Sex Workers' Health Access (AESHA) (2010-14). A modified standardized 'work stress' scale, multivariable linear regression with generalized estimating equations was used to longitudinally examine the factors associated with work stress. In multivariable analysis, poor working conditions were associated with increased work stress and included workplace physical/sexual violence (β = 0.18; 95% confidence interval (CI) 0.06, 0.29), displacement due to police (β = 0.26; 95% CI 0.14, 0.38), working in public spaces (β = 0.73; 95% CI 0.61, 0.84). Older (β = -0.02; 95% CI -0.03, -0.01) and Indigenous SWs experienced lower work stress (β = -0.25; 95% CI -0.43, -0.08), whereas non-injection (β = 0.32; 95% CI 0.14, 0.49) and injection drug users (β = 0.17; 95% CI 0.03, 0.31) had higher work stress. Vancouver-based SWs' work stress was largely shaped by poor work conditions, such as violence, policing, lack of safe workspaces. There is a need to move away from criminalized approaches which shape unsafe work conditions and increase work stress for SWs. Policies that promote SWs' access to the same occupational health, safety and human rights standards as workers in other labour sectors are also needed. © The Author 2017. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  16. 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.

  17. Strength conditions for the elastic structures with a stress error

    Science.gov (United States)

    Matveev, A. D.

    2017-10-01

    As is known, the constraints (strength conditions) for the safety factor of elastic structures and design details of a particular class, e.g. aviation structures are established, i.e. the safety factor values of such structures should be within the given range. It should be noted that the constraints are set for the safety factors corresponding to analytical (exact) solutions of elasticity problems represented for the structures. Developing the analytical solutions for most structures, especially irregular shape ones, is associated with great difficulties. Approximate approaches to solve the elasticity problems, e.g. the technical theories of deformation of homogeneous and composite plates, beams and shells, are widely used for a great number of structures. Technical theories based on the hypotheses give rise to approximate (technical) solutions with an irreducible error, with the exact value being difficult to be determined. In static calculations of the structural strength with a specified small range for the safety factors application of technical (by the Theory of Strength of Materials) solutions is difficult. However, there are some numerical methods for developing the approximate solutions of elasticity problems with arbitrarily small errors. In present paper, the adjusted reference (specified) strength conditions for the structural safety factor corresponding to approximate solution of the elasticity problem have been proposed. The stress error estimation is taken into account using the proposed strength conditions. It has been shown that, to fulfill the specified strength conditions for the safety factor of the given structure corresponding to an exact solution, the adjusted strength conditions for the structural safety factor corresponding to an approximate solution are required. The stress error estimation which is the basis for developing the adjusted strength conditions has been determined for the specified strength conditions. The adjusted strength

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Variations in water status, gas exchange, and growth in Rosmarinus officinalis plants infected with Glomus deserticola under drought conditions.

    Science.gov (United States)

    Sánchez-Blanco, Ma Jesús; Ferrández, Trinitario; Morales, Ma Angeles; Morte, Asunción; Alarcón, Juan José

    2004-06-01

    The influence of the arbuscular mycorrhizal fungus Glomus deserticola on the water relations, gas exchange parameters, and vegetative growth of Rosmarinus officinalis plants under water stress was studied. Plants were grown with and without the mycorrhizal fungus under glasshouse conditions and subjected to water stress by withholding irrigation water for 14 days. Along the experimental period, a significant effect of the fungus on the plant growth was observed, and under water stress, mycorrhizal plants showed an increase in aerial and root biomass compared to non-mycorrhizal plants. The decrease in the soil water potential generated a decrease in leaf water potential (psi(l)) and stem water potential (psi(x)) of mycorrhizal and non-mycorrhizal plants, with this decrease being lower in mycorrhizal water-stressed plants. Mycorrhization also had positive effects on the root hydraulic conductivity (Lp) of water stressed plants. Furthermore, mycorrhizal-stressed plants showed a more important decrease in osmotic potential at full turgor (psi(os)) than did non-mycorrhizal-stressed plants, indicating the capacity of osmotic adjustment. Mycorrhizal infection also improved photosynthetic activity (Pn) and stomatal conductance (g(s)) in plants under water stress compared to the non-mycorrhizal-stressed plants. A similar behaviour was observed in the photochemical efficiency of PSII (Fv/Fm) with this parameter being lower in non-mycorrhizal plants than in mycorrhizal plants under water stress conditions. In the same way, under water restriction, mycorrhizal plants showed higher values of chlorophyll content than did non-mycorrhizal plants. Thus, the results obtained indicated that the mycorrhizal symbiosis had a beneficial effect on the water status and growth of Rosmarinus officinalis plants under water-stress conditions.

  4. Screening for Osmotic Stress Responses in Rice Varieties under Drought Condition

    Directory of Open Access Journals (Sweden)

    Simon Swapna

    2017-09-01

    Full Text Available Drought is the major abiotic stress factor that limits rice production worldwide. To evaluate the osmotic stress responses in rice varieties under drought condition, a total of 42 high-yielding rice varieties were collected from various research stations of Kerala Agricultural University in India. The experimental setup comprises of initial hydroponic treatments at different osmotic potentials, artificially induced by desired strengths of polyethylene glycol (PEG6000, and followed by the pot planted experiments in the rain-out-zone. The activities of antioxidant enzymes, relative water content, cell membrane stability, photosynthetic pigments, proline content, along with plant growth parameters of the varieties under drought condition were evaluated. Moreover, the standard scores of these rice varieties were assessed under stress and recovery conditions based on the scoring scale of the Standard Evaluation System for rice. Among the 42 rice varieties, we identified 2 rice varieties, Swarnaprabha and Kattamodan, with less leaf rolling, better drought recovery ability as well as relative water content, increased membrane stability index, osmolyte accumulation, and antioxidant enzyme activities pointed towards their degree of tolerance to drought stress. The positive adaptive responses of these rice varieties towards drought stress can be used in the genetic improvement of rice drought resistance breeding program.

  5. 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.

  6. 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.

  7. Resistance of functional Lactobacillus plantarum strains against food stress conditions.

    Science.gov (United States)

    Ferrando, Verónica; Quiberoni, Andrea; Reinhemer, Jorge; Suárez, Viviana

    2015-06-01

    The survival of three Lactobacillus plantarum strains (Lp 790, Lp 813 and Lp 998) with functional properties was studied taking into account their resistance to thermal, osmotic and oxidative stress factors. Stress treatments applied were: 52 °C-15 min (Phosphate Buffer pH 7, thermal shock), H2O2 0.1% (p/v) - 30 min (oxidative shock) and NaCl aqueous solution at 17, 25 and 30% (p/v) (room temperature - 1 h, osmotic shock). The osmotic stress was also evaluated on cell growth in MRS broth added of 2, 4, 6, 8 and 10% (p/v) of NaCl, during 20 h at 30 °C. The cell thermal adaptation was performed in MRS broth, selecting 45 °C for 30 min as final conditions for all strains. Two strains (Lp 813 and Lp 998) showed, in general, similar behaviour against the three stress factors, being clearly more resistant than Lp 790. An evident difference in growth kinetics in presence of NaCl was observed between Lp 998 and Lp 813, Lp998 showing a higher optical density (OD570nm) than Lp 813 at the end of the assay. Selected thermal adaptation improved by 2 log orders the thermal resistance of both strains, but cell growth in presence of NaCl was enhanced only in Lp 813. Oxidative resistance was not affected with this thermal pre-treatment. These results demonstrate the relevance of cell technological resistance when selecting presumptive "probiotic" cultures, since different stress factors might considerably affect viability or/and performance of the strains. The incidence of stress conditions on functional properties of the strains used in this work are currently under research in our group. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. 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)

  9. VUV spectroscopy of water under cellular conditions

    International Nuclear Information System (INIS)

    Mota, R.; Parafita, R.; Maneira, M. J. P.; Mason, N. J.; Garcia, G.; Ribeiro, P. A.; Raposo, M.; Limao-Vieira, P.

    2006-01-01

    The understanding of radiation damage within cells, and thence mutagenesis, depends upon a detailed knowledge of the spectroscopy and dissociation dynamics of water. Results of a new study of the electronic state spectroscopy of water, using synchrotron radiation are reported. In order to gain some insight into how the spectroscopy and dissociation dynamics of water is influenced by its environment we also report photo-absorption spectra of water within thin films of poly(o-methoxyaniline) which have been suggested as a good mimic for biological membranes in the cellular environment. Comparison of these spectra with those of gaseous water and condensed amorphous water ice suggest that water in such films is similar to gaseous water and does not show the blue shift suggested in some cellular models. The lowest energy of OH production from dissociation of water in the cellular environment may therefore be around 6.7 eV (185 nm). (authors)

  10. 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.

  11. 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)

  12. Water level influences on body condition of Geophagus brasiliensis (Perciformes: Cichlidae in a Brazilian oligotrophic reservoir

    Directory of Open Access Journals (Sweden)

    Alejandra Filippo Gonzalez Neves dos Santos

    Full Text Available Effects of water level fluctuations on body condition of Geophagus brasiliensis were studied in a 30 km² Brazilian oligotrophic reservoir. Physiological condition (K and gonadosomatic index (GSI were compared according to water level (low and high. Females' best conditions were associated to higher resources availability during high water, since gonad development did not change between low and high water. Males' condition did not change between water levels, while the highest gonad development occurred in low water. Females presented higher reproductive investment than males, which allocated most of energy for somatic development. This strategy could be a mechanism to undergo the stress caused by oligotrophic characteristics of the reservoir enhanced during low water level.

  13. Factors affecting stress assisted corrosion cracking of carbon steel under industrial boiler conditions

    Science.gov (United States)

    Yang, Dong

    Failure of carbon steel boiler tubes from waterside has been reported in the utility boilers and industrial boilers for a long time. In industrial boilers, most waterside tube cracks are found near heavy attachment welds on the outer surface and are typically blunt, with multiple bulbous features indicating a discontinuous growth. These types of tube failures are typically referred to as stress assisted corrosion (SAC). For recovery boilers in the pulp and paper industry, these failures are particularly important as any water leak inside the furnace can potentially lead to smelt-water explosion. Metal properties, environmental variables, and stress conditions are the major factors influencing SAC crack initation and propagation in carbon steel boiler tubes. Slow strain rate tests (SSRT) were conducted under boiler water conditions to study the effect of temperature, oxygen level, and stress conditions on crack initation and propagation on SA-210 carbon steel samples machined out of boiler tubes. Heat treatments were also performed to develop various grain size and carbon content on carbon steel samples, and SSRTs were conducted on these samples to examine the effect of microstructure features on SAC cracking. Mechanisms of SAC crack initation and propagation were proposed and validated based on interrupted slow strain tests (ISSRT). Water chemistry guidelines are provided to prevent SAC and fracture mechanics model is developed to predict SAC failure on industrial boiler tubes.

  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. The behavior of Kevlar fibers under environmental-stress conditions

    Science.gov (United States)

    Perry, Mark Charles

    There are a myriad of mechanisms by which polymers can degrade and fail. It is therefore important to understand the physical mechanics, chemistry, their interactions, and kinetics. This pursuit becomes more than just "academic" because these mechanisms might just change with service conditions (i.e. environment and loading). If one does not understand these processes from the molecular to macroscopic scale it would be exceedingly difficult to gain information from accelerated testing because the mechanisms just might change from one condition to another. The purpose of this study was to probe these processes on scales ranging from molecular to macroscopic in environmental stress conditions. This study reports the results of environmental-stress degradation of Kevlar 49 fibers. The environmental agent of focus was the ubiquitous air pollutant complex NOsb{x}. Other materials and environments were investigated to a lesser extent for purposes of comparison. Mechanical property (i.e., short-term strength, modulus, and creep lifetime) degradation was examined using single fiber, yarn, and epoxy coated yarn (composite) specimens under environmental-stress conditions. Optical and scanning electron microscopes were employed to examine and compare the appearance of fracture features resulting from the various testing conditions. Atomic force microscopy augmented these studies with detailed topographical mappings and measures of the fracture surface frictional and modulus properties. Molecular processes (i.e., chain scission and other mechanical-chemical reactions) were probed by measures of changes in viscosity average molecular weight and the infrared spectra. It was demonstrated that environmental-stress degradation effects do occur in the Kevlar-NOsb{x} gas system. Strength decay in environmentally exposed unloaded fibers was demonstrated and a synergistic response in creep reduced fiber lifetimes by three orders of magnitude at moderate loadings. That is to say, the

  16. 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.

  17. 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 ...

  18. 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 ...

  19. 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

  20. Effect of Salicylic Acid on the Growth and Physiological Characteristics of Maize under Stress Conditions

    International Nuclear Information System (INIS)

    Manzoor, K.; Ilyas, N.; Batool, N.; Arshad, M.; Ahmad, B.

    2015-01-01

    Salicylic acid (SA) is a naturally occurring signaling molecule and growth regulator that enhances plant growth particularly in stress conditions. The present study was planned to evaluate the effects of different levels of SA on maize growth under drought and salt stress conditions. An experiment was conducted to test the morphological, physiological and biochemical changes in two cultivar of maize D-1184 and TG-8250. Varying levels of salicylic acid, i.e. 5mM, 10mM and 15mM were applied through foliar method. Exogenous applications of salicylic acid were done after 20 days of germination of the maize plants. Salicylic acid significantly affects root and shoot dry matter under drought and salt stress. Foliar application of SA significantly increased proline concentration (11 percentage and 12 percentage), amino acid accumulation (25 percentage and 18 percentage), relative water (17 percentage and 14 percentage) and Chlorophyll content. Overall, it can be concluded that SA at lower concentration is effective to minimize the effect of stress conditions. Maize cultivar TG-8250 showed better tolerance under drought and salt stress condition as compared to D-1184 cultivar. (author)

  1. 42 CFR 494.40 - Condition: Water and dialysate quality.

    Science.gov (United States)

    2010-10-01

    ... demonstrate the following: (a) Standard: Water purity. Water and equipment used for dialysis meets the water... Boulevard, Suite 400, Arlington, VA 22201-4598. (b) Standard: Chlorine/chloramines. (1) The water treatment... 42 Public Health 5 2010-10-01 2010-10-01 false Condition: Water and dialysate quality. 494.40...

  2. Amelioration of Heat-Stress Conditions of Egyptian Summer Season on Friesian Calves Using Air Condition

    International Nuclear Information System (INIS)

    Nessim, M.Z.; Kamal, T.H.; Khalil, W.K.B.

    2010-01-01

    Male Friesian calves were used to evaluate cool air condition (AC) in alleviating heat stress (HS) determined by Heat Shock Protein genes expression (HSP), hormonal, biochemical and physiological parameters. The animals were exposed to summer heat stress (HS) under shade for two weeks (control). The maximum temperature humidity index (THI) during summer HS was from 81 to 88. Afterward the animals were exposed to AC, inside a climatic chamber for 6 hours daily for two weeks, where, the THI was from 70 to 71. The results revealed that expression level of the Hsp genes (Hsp72, Hsp70.1, Hsp70 and Hsp47) was lower under air condition treatment than under summer heat stress. Rectal temperature and respiration rate were significantly lower (p< 0.01) under air condition treatment than those under heat stress. Total triiodothyronin (T3) level was significantly higher (P< 0.05) in AC cooling treatments than in HS, while cortisol level was significantly lower (P < 0.01) in AC cooling treatment than in HS calves. Creatinine and Urea -N levels were significantly lower (P < 0.01) in AC cooling treatment than in HS calves. Triglycerides, ALT and AST levels were significantly lower (p<0.01), (P< 0.01) and (p<0.05), respectively in AC cooling treatment than in HS calves. These results demonstrated that there is a relationship between the molecular weight of HSPs and the level of HSPs gene exprisson. The higher the molecular weight (HSP 72) the lower is the HSPs gene expression level (0.82 in HS and 0.39 in AC) and vise versa. This holds true in both heat stress and air condition. AC treatment is capable to ameliorate heat stress of Friesian calves under hot summer climate

  3. Characterization of sensitization and stress corrosion cracking behavior of stabilized stainless steels under BWR conditions

    International Nuclear Information System (INIS)

    Kilian, R.; Ilg, U.; Meier, V.; Teichmann, H.; Wachter, O.

    1995-01-01

    Stress corrosion cracking occurs if the three parameters -- material condition, tensile stress and water chemistry -- are in a critical range. In this study the material conditions especially of Ti- and Nb-stabilized steels are considered. The purpose of this work is to show the influence of the degree of sensitization of Ti- and Nb-stabilized stainless steels on stress corrosion cracking susceptibility in BWR water chemistry. This is an on-going research program. Preliminary results will be presented. Different types of stabilized, and for comparison unstabilized, stainless steels are examined in various heat treatment conditions with regard to their sensitization behavior by EPR tests (double loop) and TEM. The results are plotted in sensitization diagrams. The sensitization behavior depends on many parameters such as carbon content, stabilization element, stabilization ratio and materials history, e.g. solution heat treatment or cold working. The obtained EPR sensitization diagrams are compared with the well known sensitization diagrams from the literature, which were determined by standard IC test according to e.g. German standard DIN 50914 (equivalent to ASTM A 262, Pract. E). Based on the obtained EPR sensitization diagrams material conditions for SSRT tests were selected. The EPR values (Ir/Ia x 100%) of the tested Ti-stabilized stainless steel are in the range of ∼ 0.1--20%. The SSRT tests are carried out in high-temperature water with 0.4 ppm O 2 , a conductivity of 0.5 microS/cm and a strain rate of 1x10 -6-1 . The test temperature is 280 C. Ti-stabilized stainless steel with Ir/Ia x 100% > 1% suffered intergranular stress corrosion cracking under these conditions. The SCC tests for Nb-stabilized stainless steel are still in progress. The correlation between EPR value, chromium depletion and SSRT result will be shown for a selected material condition of sensitized Ti-stabilized stainless steel

  4. 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

  5. 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...

  6. 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 ...

  7. 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

  8. 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.

  9. Evaluation of some sorghum genotypes under normal and moisture-stress conditions

    International Nuclear Information System (INIS)

    Abu Assar, A. H.; Salih, M.; Wagner, C.; Friedt, W.; Abdelmula, A. A.; Ordon, F.; Steffens, D.

    2008-01-01

    This study was undertaken to identify the morphological and physiological attributes related to drought tolerance in sorghum (sorghum bicolor (L) Moench). Eight genotypes were tested in a pot experiment carried out at Giessen, Germany. Drought conditions were imposed by withholding watering of the plants when filed water-holding capacity was at 40% and 70%. The tested genotypes differed significantly in most of the measured traits. Grain yield under drought stress ranged from 28 to 61 g/ plant, and relative yield ranged 30% to 56% with an average of 47%. Based on yield/plant, the genotypes Wad Ahmed (61g). SAR 41 (55 g) and ICSR 91030 (54 g) were the best under drought stress conditions, and based on relative yield, the best genotypes were SAR 41 (56%), Wad Ahmed (55%), and Red Mugud (53%). The mean potassium content was 18 mg/g, with a range of 14 mg/g (Red Mugud) to 22 mg/g (Arfa Gadamak). Significant difference were obtained for protein percentage of the dry matter under conditions of drought stress. The values ranged form 14.1% (Red Mugud) to 16.7% (Tabat) with a mean of 15.3%. Grain yield under drought stress was positively correlated with relative yield (r= 0.89), total biomass (r= 0.56), number of seeds per panicle (r= 0.66) and harvest index (r= 0.81), but negatively correlated with 1000-grain (r= 0.37). (Author)

  10. 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)

  11. 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)

  12. Unsteady exergy destruction of the neuron under dynamic stress conditions

    International Nuclear Information System (INIS)

    Genc, S.; Sorguven, E.; Ozilgen, M.; Aksan Kurnaz, I.

    2013-01-01

    Just like all physical systems, biological systems also obey laws of thermodynamics, and as such the useful work potential of a biological system is its exergy. In some studies, exergy of living systems is considered with respect to work performance of humans in offices or buildings; however the exergy analysis of biochemical reactions in a cell as a closed system goes largely untouched. In this study, exergy analysis was applied to glucose metabolism of a model neuron, and dynamic exergy destructions were calculated for four different conditions, namely normoxia, hypoxia, glucose starvation and excess glucose. Our results showed that neuronal metabolism achieved a new steady state under each condition within 5 min. This dynamic model predicts that, both exergy destruction and work potential rates increase with increasing blood glucose concentration. The ratio of exergy destruction rate to work potential rate increases logarithmically with increasing blood glucose concentration. The neuronal metabolism is thus found to function in an efficient way and switches to lower exergy destruction under stress conditions such as glucose starvation. This behavior seen in this exergy analysis study confirms the assumption of minimum entropy production in living systems. - Highlights: • Unsteady exergy analysis of glucose metabolism of a model neuron is performed. • Dynamic exergy losses were calculated for four different conditions: normoxia, hypoxia, glucose starvation and excess glucose. • Neuronal metabolism achieved a new steady state under each condition within 5 min. • Both exergy loss and work potential rates increase with increasing blood glucose concentration. • Neuronal metabolism functions in an efficient way and switches to lower exergy loss under stress conditions

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. Aggradation, Degradation, and Water Quality Conditions

    National Research Council Canada - National Science Library

    1993-01-01

    The purpose of this study is to compile a record of pertinent data and information relative to aggradation, degradation, and water quality within the system of six Missouri River mainstem reservoirs...

  18. Cooling tower water conditioning study. [using ozone

    Science.gov (United States)

    Humphrey, M. F.; French, K. R.

    1979-01-01

    Successful elimination of cooling tower treatment chemicals was demonstrated. Three towers functioned for long periods of time with ozone as the only treatment for the water. The water in the systems was reused as much as 30 times (cycles of concentration) without deleterious effects to the heat exchangers. Actual system blow-down was eliminated and the only makeup water added was that required to replace the evaporation and mist entrainment losses. Minimum water savings alone are approximately 75.1 1/kg/year. Cost estimates indicate that a savings of 55 percent was obtained on the systems using ozone. A major problem experienced in the use of ozone for cooling tower applications was the difficulty of accurate concentration measurements. The ability to control the operational characteristics relies on easily and accurately determined concentration levels. Present methods of detection are subject to inaccuracies because of interfering materials and the rapid destruction of the ozone.

  19. 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 ...

  20. 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.

  1. Environmental effects on proline accumulation and water potential in olive leaves (Olea europaea L. (cv Chemlali)) under saline water irrigated field conditions

    Energy Technology Data Exchange (ETDEWEB)

    Ben Ahmed, C.; Ben Rouina, B.; Boukhris, M.

    2009-07-01

    In arid regions in Tunisia suffering from limited water resources, the olive extension to irrigated lands has led to the urgent use of saline water, the most readily available water in the these areas. Nevertheless, the effects of salt stress on olive tree seem to be reinforced by environmental conditions. The issue of this paper is to determine how does the olive tree respond to environmental stress in the Mediterranean climate under saline water irrigated field conditions with respect to leaf proline concentrations and water Status. (Author)

  2. Environmental effects on proline accumulation and water potential in olive leaves (Olea europaea L. CV Chemlali)) under saline water irrigated field conditions

    International Nuclear Information System (INIS)

    Ben Ahmed, C.; Ben Rouina, B.; Boukhris, M.

    2009-01-01

    In arid regions in Tunisia suffering from limited water resources, the olive extension to irrigated lands has led to the urgent use of saline water, the most readily available water in the these areas. Nevertheless, the effects of salt stress on olive tree seem to be reinforced by environmental conditions. The issue of this paper is to determine how does the olive tree respond to environmental stress in the Mediterranean climate under saline water irrigated field conditions with respect to leaf proline concentrations and water Status. (Author)

  3. Performance of diverse wheat genetic stocks under moisture stress condition

    International Nuclear Information System (INIS)

    Seher, M.; Shabbir, G.; Rasheed, A.

    2015-01-01

    This study was conducted to evaluate divergent wheat germplasm for their performance under drought and control conditions. The germplasm consists of wheat land races of Pakistan, advanced D-genome synthetic derivatives and high yielding varieties of Pakistan. This wide array of germplasm was selected to identify sources, which can be opted later by the wheat breeders while breeding for drought tolerance. The evaluation parameters involved some important physiochemical testing and morphological characteristics in the field under drought and control conditions. Based on these parameters, 13 wheat genotypes were selected on the basis of their best performance regarding morphological and physiological parameters. These genotypes exhibited higher yield under drought stress conditions and increased percentage of proline, sugar, SOD and protein content under laboratory conditions as compared to the susceptible genotypes. Correlation studies revealed that grains per spike (GPS) and thousand grain weight (TGW) had direct relationship with spike length (SL), proline and sugar content under both control and drought conditions. Thus, these parameters can be used as selection criteria for the identification of tolerant genotypes. (author)

  4. 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.

  5. 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

  6. Effect of Filter Cake on Morphophysiological and Yield of Sweet Corn Under Late Season Drought Stress Condition

    Directory of Open Access Journals (Sweden)

    S. A. Siadat

    2015-06-01

    Full Text Available In order to investigate the effect of Filter Cake application on some morpho-physiological characteristics and yield of sweet corn (Zea mays var saccharata under different irrigation regimes, an experiment was conducted in Ramin Agriculture and Natural Resources University, Khuzestan, in 2012. The experiment was arranged in split-plot design in RCBD (Completely Randomized Block Design with three replications. Treatments were drought stress (irrigation after 25, 50 and 75% depletion of available water content in main plots and Filter Cake (0, 10, 20 and 30 tonha-1 arranged in sub-plots. Results showed that drought stress increased electrolyte leakage (EL and proline content (PC while height of plant, relative water content (RWC, chlorophyll stability index and ear and grain yield were decreased. The intensive drought stress had the greatest effect on EL and PC (54% increase, and decreased ear and grain yield by21 and 37% compared to control, respectively. Application of filter cake on non-stress condition increased height of plant and economic yield. But Filter Cake in intensive stress reduced RWC and yield and increased EL compared to control. Also, the application of 30 tonha-1 of Filter Cake in intensive stress condition decreased ear and grain yield by 14.5 and 10.7% respectively. Thus, positive effect of Filter Cake application was clear on non-stress condition, but on drought stress condition it decreased the economic yield.

  7. On the influence of abiotic stress conditions on growth of barley and bean and their predisposition for pathogens

    Energy Technology Data Exchange (ETDEWEB)

    Oerke, E.C.; Schoenbeck, F.

    1986-01-01

    Shorttime changes of environmental conditions stressed barley and bean and affected plant growth and their predisposition for various pathogens. Moderate stress intensities as low or high temperatures, water or light deficits, increased the susceptibility to Erysiphe graminis var. hordei or Uromyces phaseoli and reduced disease level of spot blotch caused by Cochliobolus sativus, respectively. There was only little effect on plant growth in that case. Intensive stress as a result of combinations of unfavorable environmental conditions or longtime continuance of moderate stress reduced the plant growth and turned the predisposing effect to the opposite: after the treatment, plants were more resistent to diseases caused by biotrophic fungi, whereas there was increased susceptibility to the perthotrophic fungus. High intensities of fertilization acted as an additional stress and intensified the plant reaction to environmental alterations. The variation of the predisposition is discussed in relation to stress intensity.

  8. Understanding Vocalization Might Help to Assess Stressful Conditions in Piglets

    Directory of Open Access Journals (Sweden)

    Diego Pereira Neves

    2013-09-01

    Full Text Available Assessing pigs’ welfare is one of the most challenging subjects in intensive pig farming. Animal vocalization analysis is a noninvasive procedure and may be used as a tool for assessing animal welfare status. The objective of this research was to identify stress conditions in piglets reared in farrowing pens through their vocalization. Vocal signals were collected from 40 animals under the following situations: normal (baseline, feeling cold, in pain, and feeling hunger. A unidirectional microphone positioned about 15 cm from the animals’ mouth was used for recording the acoustic signals. The microphone was connected to a digital recorder, where the signals were digitized at the 44,100 Hz frequency. The collected sounds were edited and analyzed. The J48 decision tree algorithm available at the Weka® data mining software was used for stress classification. It was possible to categorize diverse conditions from the piglets’ vocalization during the farrowing phase (pain, cold and hunger, with an accuracy rate of 81.12%. Results indicated that vocalization might be an effective welfare indicator, and it could be applied for assessing distress from pain, cold and hunger in farrowing piglets.

  9. 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)

  10. Mechanism of laser ablation for aqueous media irradiated under confined-stress conditions

    International Nuclear Information System (INIS)

    Oraevsky, A.A.; Jacques, S.L.; Tittel, F.K.

    1995-01-01

    Pulsed laser ablation of aqueous medium irradiated under conditions of temporal confinement of thermal stress is described. Time-resolved measurements of laser-induced transient stress waves with simultaneous imaging of ablation process by laser-flash photography were performed. Stress transients induced in aqueous solution of K 2 CrO 4 by ablative nanosecond laser pulses at 355 nm were studied by a broad-band lithium niobate acoustic transducer. Recoil momentum upon material ejection was measured from the temporal profiles of the acoustic transducer signal as a function of incident laser fluence. Cavitation bubbles produced in the irradiated volume during the tensile phase of thermoelastic stress were shown to drive material ejection at temperatures substantially below 100 degree C. Experimental data are evident that nanosecond-pulse laser ablation of aqueous media (when temporal stress-confinement conditions are satisfied) include the following two main stages of material ejection: (1) ejection of water microdroplets due to expansion and rupture of subsurface cavitation bubbles; (2) ejection of liquid streams with substantial volume upon collapse of initial crater and large cavitation bubbles in the depth of irradiated volume (after coalescence of smaller bubbles). copyright 1995 American Institute of Physics

  11. 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 ...

  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. 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.

  17. TPX vacuum vessel transient thermal and stress conditions

    International Nuclear Information System (INIS)

    Feldshteyn, Y.; Dinkevich, S.; Feng, T.; Majumder, D.

    1995-01-01

    The TPX vacuum vessel provides the vacuum boundary for the plasma and the mechanical support for the internal components. Another function of the vacuum vessel is to contain neutron shielding water in the double wall space during normal operation. This double wall space serves as a heat reservoir for the entire vacuum vessel during bakeout. The vacuum vessel and the internal components are subjected to thermal stresses induced by a nonuniform temperature distribution within the structure during bakeout. A successful Conceptual Design Review in March 1993 has established superheated steam as the heating source of the vacuum vessel. A transient bakeout mode of the vacuum vessel and in-vessel components has been analyzed to evaluate transient period duration, proper temperature level, actual thermal stresses and performance of the steam equipment. Thermally, the vacuum vessel structure may be considered as an adiabatic system because it is perfectly insulated by the strong surrounding vacuum and multiple layers of superinsulation. Important aspects of the analysis are described herein

  18. 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

  19. Physiological studies on photochemical oxidant injury in rice plants. III. Relationship between abscisic acid (ABA) and water metabolism in water-stressed rice plants

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Y.H.; Ota, Y.

    1981-12-01

    Several experiments were carried out to determine the effects of exogenously applied ABA on water metabolism, and to clarify the endogenous ABA relationships in ozone-sensitivity under different soil water content in rice plants. The rice plants were cultivated in soil with 60, 80, and 100% of maximum water holding capacity and under submerged condition. The results of the experiments were as follows: ozone injury was reduced with increasing ABA content of which production was increased under water stress conditions. Under water stressed conditions, the rate of water loss was decreased with increasing concentration of ABA applied exogenously. It may be assumed that the ozone-sensitivity is closely related to the stomatal closure caused by the increased ABA content due to water stress. 5 references, 4 tables.

  20. Genome-wide transcriptome analysis of soybean primary root under varying water-deficit conditions.

    Science.gov (United States)

    Song, Li; Prince, Silvas; Valliyodan, Babu; Joshi, Trupti; Maldonado dos Santos, Joao V; Wang, Jiaojiao; Lin, Li; Wan, Jinrong; Wang, Yongqin; Xu, Dong; Nguyen, Henry T

    2016-01-15

    Soybean is a major crop that provides an important source of protein and oil to humans and animals, but its production can be dramatically decreased by the occurrence of drought stress. Soybeans can survive drought stress if there is a robust and deep root system at the early vegetative growth stage. However, little is known about the genome-wide molecular mechanisms contributing to soybean root system architecture. This study was performed to gain knowledge on transcriptome changes and related molecular mechanisms contributing to soybean root development under water limited conditions. The soybean Williams 82 genotype was subjected to very mild stress (VMS), mild stress (MS) and severe stress (SS) conditions, as well as recovery from the severe stress after re-watering (SR). In total, 6,609 genes in the roots showed differential expression patterns in response to different water-deficit stress levels. Genes involved in hormone (Auxin/Ethylene), carbohydrate, and cell wall-related metabolism (XTH/lipid/flavonoids/lignin) pathways were differentially regulated in the soybean root system. Several transcription factors (TFs) regulating root growth and responses under varying water-deficit conditions were identified and the expression patterns of six TFs were found to be common across the stress levels. Further analysis on the whole plant level led to the finding of tissue-specific or water-deficit levels specific regulation of transcription factors. Analysis of the over-represented motif of different gene groups revealed several new cis-elements associated with different levels of water deficit. The expression patterns of 18 genes were confirmed byquantitative reverse transcription polymerase chain reaction method and demonstrated the accuracy and effectiveness of RNA-Seq. The primary root specific transcriptome in soybean can enable a better understanding of the root response to water deficit conditions. The genes detected in root tissues that were associated with

  1. 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)

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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...

  8. Behavior of stressed and unstressed 304L specimens in tuff repository environmental conditions

    International Nuclear Information System (INIS)

    Juhas, M.C.; McCright, R.D.; Garrison, R.E.

    1984-11-01

    This paper presents preliminary results of an investigation of the behavior of candidate barrier material for high-level nuclear waste storage, Type 304L stainless steel, in tuff repository environmental conditions. Tuff is a densely welded, devitrified, igneous rock common to the proposed repository site at Yucca Mountain, Nevada. The results discussed include: irradiation corrosion tests, U-bend irradiation corrosion tests, slow strain rate tests, and bent beam stress corrosion tests. Results indicate that Type 304L stainless steel shows excellent resistance to general, localized, and stress corrosion under the environmental and microstructural conditions tested so far. The environmental test conditions are 50 to 100 0 C J-13 well water (non-saline, near neutral pH, and oxic in nature) and saturated steam at 100 0 C. Microstructural conditions include solution annealed and long furnace heat treatments to provoke a sensitized structure. However, this particular type of stainless steel may be susceptible to long-term, low-temperature sensitization because of the combination of expected time at elevated temperature and residual stress in the container after emplacement in the repository. Other grades of austenitic stainless steels are reported to be more resistant to low-temperature sensitization. Future work will therefore include more extensive testing of these grades. 15 references, 5 figures, 7 tables

  9. 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...

  10. 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.

  11. 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.

  12. 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.

  13. 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...

  14. Mediator phosphorylation prevents stress response transcription during non-stress conditions.

    Science.gov (United States)

    Miller, Christian; Matic, Ivan; Maier, Kerstin C; Schwalb, Björn; Roether, Susanne; Strässer, Katja; Tresch, Achim; Mann, Matthias; Cramer, Patrick

    2012-12-28

    The multiprotein complex Mediator is a coactivator of RNA polymerase (Pol) II transcription that is required for the regulated expression of protein-coding genes. Mediator serves as an end point of signaling pathways and regulates Pol II transcription, but the mechanisms it uses are not well understood. Here, we used mass spectrometry and dynamic transcriptome analysis to investigate a functional role of Mediator phosphorylation in gene expression. Affinity purification and mass spectrometry revealed that Mediator from the yeast Saccharomyces cerevisiae is phosphorylated at multiple sites of 17 of its 25 subunits. Mediator phosphorylation levels change upon an external stimulus set by exposure of cells to high salt concentrations. Phosphorylated sites in the Mediator tail subunit Med15 are required for suppression of stress-induced changes in gene expression under non-stress conditions. Thus dynamic and differential Mediator phosphorylation contributes to gene regulation in eukaryotic cells.

  15. Ground-water conditions in Utah, spring of 1994

    Science.gov (United States)

    Allen, D.V.; Garrett, R.B.; Sory, J.D.; Burden, Carole B.; Danner, M.R.; Herbert, L.R.; Steiger, J.I.; ReMillard, M.D.; Slaugh, B.A.; Swenson, R.L.; Howells, J.H.; Christiansen, H.K.; Bagley, A.D.

    1994-01-01

    This is the thirty-first in a series of annual reports that describe ground-water conditions in Utah. Reports in this series, published cooperatively by the U.S. Geological Survey and the Utah Division of Water Resources, provide data to enable interested parties to keep abreast of changing ground-water conditions.This report, like the others in the series, contains information on well construction, ground-water withdrawal from wells, water-level changes, related changes in precipitation and streamflow, and chemical quality of water. Supplementary data, such as maps showing water-level contours, are included in reports of this series only for those years or areas for which applicable data are available and are important to a discussion of changing ground-water conditions.This report includes individual discussions of selected significant areas of ground-water development in the State for calendar year 1993. Water-level fluctuations and selected related data, however, are described from the spring of 1989 to the spring of 1994. Much of the data used in this report were collected by the U.S. Geological Survey in cooperation with the Divisions of Water Rights and Water Resources, Utah Department of Natural Resources.

  16. 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)

  17. 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.

  18. 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.

  19. 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.

  20. Measuring Bus Drivers' Occupational Stress Under Changing Working Conditions

    NARCIS (Netherlands)

    Hlotova, Y.; Cats, O.; Meijer, S.A.

    2014-01-01

    Stress is an immense problem in modern society; approximately half of all occupational illnesses are directly or indirectly related to stress. The work of a bus driver is typically associated with high stress levels that negatively influence individual well-being as well as workforce management. The

  1. 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)

  2. Ground-water conditions in Utah, spring of 1995

    Science.gov (United States)

    Allen, D.V.; Steiger, J.I.; Sory, J.D.; Garrett, R.B.; Burden, Carole B.; Danner, M.R.; Herbert, L.R.; Gerner, S.J.; Slaugh, B.A.; Swenson, R.L.; Howells, J.H.; Christiansen, H.K.; Bagley, A.D.

    1995-01-01

    This is the thirty-second in a series of annual reports that describe ground-water conditions in Utah. Reports in this series, published cooperatively by the U.S. Geological Survey and the Utah Department of Natural Resources, Division of Water Resources, provide data to enable interested parties to keep abreast of changing ground-water conditions.This report, like the others in the series, contains information on well construction, ground-water withdrawal from wells, water-level changes, related changes in precipitation and streamflow, and chemical quality of water. Supplementary data, such as maps showing water-level contours, are included in reports of this series only for those years or areas for which applicable data are available and are important to a discussion of changing ground-water conditions.This report includes individual discussions of selected significant areas of ground-water development in the State for calendar year 1994. Much of the reported data were collected by the U.S. Geological Survey in cooperation with the Utah Department of Natural Resources, Divisions of Water Rights and Water Resources.

  3. Effect of abiotic stress under light and dark conditions on carotenoid ...

    African Journals Online (AJOL)

    The aim of this study was to observe the effect of abiotic stress under light and dark conditions on pumpkin calluses carotenoid. Plant elicitors used to create abiotic stress in this study were Polyethylene Glycol 4000 for drought stress, Jasmonic Acid and Salicylic Acid for hormones stress and Murashige and Skoog Salt for ...

  4. 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.

  5. Seasonal carbon storage and growth in Mediterranean tree seedlings under different water conditions.

    Science.gov (United States)

    Sanz-Pérez, Virginia; Castro-Díez, Pilar; Joffre, Richard

    2009-09-01

    In all Mediterranean-type ecosystems, evergreen and deciduous trees differing in wood anatomy, growth pattern and leaf habit coexist, suggesting distinct adaptative responses to environmental constraints. This study examined the effects of summer water stress on carbon (C) storage and growth in seedlings of three coexisting Mediterranean trees that differed in phenology and wood anatomy characteristics: Quercus ilex subsp. ballota (Desf.) Samp., Quercus faginea Lam. and Pinus halepensis L. Seedlings were subjected to two levels of watering during two consecutive summers and achieved a minimum of -0.5 and -2.5 MPa of predawn water potential in the control and water stress treatment, respectively. Both Quercus species concentrated their growth in the early growing season, demanding higher C in early spring but replenishing C-stores in autumn. These species allocated more biomass to roots, having larger belowground starch and lipid reserves. Quercus species differed in seasonal storage dynamics from P. halepensis. This species allocated most of its C to aboveground growth, which occurred gradually during the growing season, leading to fewer C-reserves. Soluble sugar and starch concentrations sharply declined in August in P. halepensis, probably because reserves support respiration demands as this species closed stomata earlier under water stress. Drought reduced growth of the three species, mainly in Q. faginea and P. halepensis, but not C-reserves, suggesting that growth under water stress conditions is not limited by C-availability.

  6. 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

  7. Anticipatory stress influences decision making under explicit risk conditions.

    Science.gov (United States)

    Starcke, Katrin; Wolf, Oliver T; Markowitsch, Hans J; Brand, Matthias

    2008-12-01

    Recent research has suggested that stress may affect memory, executive functioning, and decision making on the basis of emotional feedback processing. The current study examined whether anticipatory stress affects decision making measured with the Game of Dice Task (GDT), a decision-making task with explicit and stable rules that taps both executive functioning and feedback learning. The authors induced stress in 20 participants by having them anticipate giving a public speech and also examined 20 comparison subjects. The authors assessed the level of stress with questionnaires and endocrine markers (salivary cortisol and alpha-amylase), both revealing that speech anticipation led to increased stress. Results of the GDT showed that participants under stress scored significantly lower than the comparison group and that GDT performance was negatively correlated with the increase of cortisol. Our results indicate that stress can lead to disadvantageous decision making even when explicit and stable information about outcome contingencies is provided.

  8. The Role of Silicon under Biotic and Abiotic Stress Conditions

    Directory of Open Access Journals (Sweden)

    İlkay YAVAŞ

    2017-06-01

    Full Text Available Biotic and abiotic stress factors can adversely affect the agricultural productivity leading to physiological and biochemical damage to crops. Therefore, the most effective way is to increase the resistance to stresses. Silicon plays a ro le in reducing the effects of abiotic and biotic stresses (drought, salt stress, disease and insect stress etc. on plants. Silicon is accumulated in the cell walls and intercellular spaces and thus it has beneficial effects on disease infestations in especially small grains. The application of silicon may reduce the effects of environmental stresses on plants while making effective use of plant nutrients such as nitrogen and phosphorous. Also, silicon may reduce the toxic effects of heavy metals in soil. I t may protect the foliage and increase light uptake and reduce respiration. Therefore, in this review, we discussed the effects of silicon on abiotic and biotic stresses in especially field crops.

  9. 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...

  10. 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.

  11. 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,...

  12. Thermomechanical conditions and stresses on the friction stir welding tool

    Science.gov (United States)

    Atthipalli, Gowtam

    Friction stir welding has been commercially used as a joining process for aluminum and other soft materials. However, the use of this process in joining of hard alloys is still developing primarily because of the lack of cost effective, long lasting tools. Here I have developed numerical models to understand the thermo mechanical conditions experienced by the FSW tool and to improve its reusability. A heat transfer and visco-plastic flow model is used to calculate the torque, and traverse force on the tool during FSW. The computed values of torque and traverse force are validated using the experimental results for FSW of AA7075, AA2524, AA6061 and Ti-6Al-4V alloys. The computed torque components are used to determine the optimum tool shoulder diameter based on the maximum use of torque and maximum grip of the tool on the plasticized workpiece material. The estimation of the optimum tool shoulder diameter for FSW of AA6061 and AA7075 was verified with experimental results. The computed values of traverse force and torque are used to calculate the maximum shear stress on the tool pin to determine the load bearing ability of the tool pin. The load bearing ability calculations are used to explain the failure of H13 steel tool during welding of AA7075 and commercially pure tungsten during welding of L80 steel. Artificial neural network (ANN) models are developed to predict the important FSW output parameters as function of selected input parameters. These ANN consider tool shoulder radius, pin radius, pin length, welding velocity, tool rotational speed and axial pressure as input parameters. The total torque, sliding torque, sticking torque, peak temperature, traverse force, maximum shear stress and bending stress are considered as the output for ANN models. These output parameters are selected since they define the thermomechanical conditions around the tool during FSW. The developed ANN models are used to understand the effect of various input parameters on the total

  13. 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.

  14. 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

  15. Bridge pressure flow scour for clear water conditions

    Science.gov (United States)

    2009-10-01

    The equilibrium scour at a bridge caused by pressure flow with critical approach velocity in clear-water simulation conditions was studied both analytically and experimentally. The flume experiments revealed that (1) the measured equilibrium scour pr...

  16. 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

  17. 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)

  18. Flux Balance Analysis of Escherichia coli under Temperature and pH Stress Conditions

    KAUST Repository

    Xu, Xiaopeng

    2015-01-01

    important roles in specific conditions and are essential genes under those conditions. E. coli is a model organism, which is widely used. It can adapt to many stress conditions, including temperature, pH, osmotic, antibiotic, etc. Underlying mechanisms

  19. 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

    Arid climates have unpredictable precipitation patterns, and wildlife managers often provide supplemental water to help desert ungulates endure the hottest, driest periods. When surface water is unavailable, the only source of water for ungulates comes from the forage they consume, and they must make resourceful foraging decisions to meet their requirements. We compared two desert bighorn sheep (Ovis canadensis nelsoni) populations in Arizona, USA: a treatment population with supplemental water removed during treatment, and a control population. We examined whether sheep altered their seasonal diets without supplemental water. We calculated water and nutrient intake and metabolic water production from dry matter intake and forage moisture and nitrogen content, to determine whether sheep could meet their seasonal daily water and nutrient requirements solely from forage. Diets of sheep were higher in protein (all seasons) and moisture (autumn and winter) during treatment compared to pretreatment. During treatment, sheep diet composition was similar between the treatment and control populations, which suggests, under the climatic conditions of this study, water removal did not influence sheep diets. We estimated that under drought conditions, without any surface water available (although small ephemeral potholes would contain water after rains), female and male sheep would be unable to meet their daily water requirements in all seasons, except winter, when reproductive females had a nitrogen deficit. We determined that sheep could achieve water and nutrient balances in all seasons by shifting their total diet proportions by 8-55% from lower to higher moisture and nitrogen forage species. We elucidate how seasonal forage quality and foraging decisions by desert ungulates allow them to cope with their xeric and uncertain environment, and suggest that, with the forage conditions observed in our study area during this study period, providing supplemental water during

  20. 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

    Full Text Available Arid climates have unpredictable precipitation patterns, and wildlife managers often provide supplemental water to help desert ungulates endure the hottest, driest periods. When surface water is unavailable, the only source of water for ungulates comes from the forage they consume, and they must make resourceful foraging decisions to meet their requirements. We compared two desert bighorn sheep (Ovis canadensis nelsoni populations in Arizona, USA: a treatment population with supplemental water removed during treatment, and a control population. We examined whether sheep altered their seasonal diets without supplemental water. We calculated water and nutrient intake and metabolic water production from dry matter intake and forage moisture and nitrogen content, to determine whether sheep could meet their seasonal daily water and nutrient requirements solely from forage. Diets of sheep were higher in protein (all seasons and moisture (autumn and winter during treatment compared to pretreatment. During treatment, sheep diet composition was similar between the treatment and control populations, which suggests, under the climatic conditions of this study, water removal did not influence sheep diets. We estimated that under drought conditions, without any surface water available (although small ephemeral potholes would contain water after rains, female and male sheep would be unable to meet their daily water requirements in all seasons, except winter, when reproductive females had a nitrogen deficit. We determined that sheep could achieve water and nutrient balances in all seasons by shifting their total diet proportions by 8-55% from lower to higher moisture and nitrogen forage species. We elucidate how seasonal forage quality and foraging decisions by desert ungulates allow them to cope with their xeric and uncertain environment, and suggest that, with the forage conditions observed in our study area during this study period, providing supplemental

  1. 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

    Arid climates have unpredictable precipitation patterns, and wildlife managers often provide supplemental water to help desert ungulates endure the hottest, driest periods. When surface water is unavailable, the only source of water for ungulates comes from the forage they consume, and they must make resourceful foraging decisions to meet their requirements. We compared two desert bighorn sheep (Ovis canadensis nelsoni) populations in Arizona, USA: a treatment population with supplemental water removed during treatment, and a control population. We examined whether sheep altered their seasonal diets without supplemental water. We calculated water and nutrient intake and metabolic water production from dry matter intake and forage moisture and nitrogen content, to determine whether sheep could meet their seasonal daily water and nutrient requirements solely from forage. Diets of sheep were higher in protein (all seasons) and moisture (autumn and winter) during treatment compared to pretreatment. During treatment, sheep diet composition was similar between the treatment and control populations, which suggests, under the climatic conditions of this study, water removal did not influence sheep diets. We estimated that under drought conditions, without any surface water available (although small ephemeral potholes would contain water after rains), female and male sheep would be unable to meet their daily water requirements in all seasons, except winter, when reproductive females had a nitrogen deficit. We determined that sheep could achieve water and nutrient balances in all seasons by shifting their total diet proportions by 8–55% from lower to higher moisture and nitrogen forage species. We elucidate how seasonal forage quality and foraging decisions by desert ungulates allow them to cope with their xeric and uncertain environment, and suggest that, with the forage conditions observed in our study area during this study period, providing supplemental water during

  2. Growth and carbon assimilation limitations in Ricinus communis (Euphorbiaceae under soil water stress conditions Crescimento e limitações à assimilação de carbono em Ricinus communis (Euphorbiaceae sob condições de estresse hídrico do solo

    Directory of Open Access Journals (Sweden)

    Tanise Luisa Sausen

    2010-09-01

    Full Text Available Water availability may influence plant carbon gain and growth, with large impacts on plant yield. Ricinus communis (L., a drought resistant species, is a crop with increasing economic importance in Brazil, due to its use in chemical industry and for the production of biofuels. Some of the mechanisms involved in this drought resistance were analyzed in this study by imposing progressive water stress to pot-grown plants under glasshouse conditions. Water withholding for 53 days decreased soil water gravimetric content and the leaf water potential. Plant growth was negatively and significantly reduced by increasing soil water deficits. With irrigation suspension, carbon assimilation and transpiration were reduced and remained mostly constant throughout the day. Analysis of A/Ci curves showed increased stomatal limitation, indicating that limitation imposed by stomatal closure is the main factor responsible for photosynthesis reduction. Carboxylation efficiency and electron transport rate were not affected by water stress up to 15 days after withholding water. Drought resistance of castor bean seems to be related to a pronounced, early growth response, an efficient stomatal control and the capacity to keep high net CO2 fixation rates under water stress conditions.A disponibilidade hídrica pode influenciar o ganho de carbono e o crescimento, com grande impacto na produtividade das plantas. Ricinus communis (L., uma espécie resistente à seca, é uma cultura de grande importância econômica no Brasil, devido ao seu uso na indústria química e para a produção de biocombustíveis. Alguns dos mecanismos envolvidos na resistência à seca desta espécie foram analisados através de um progressivo estresse hídrico em plantas cultivadas em vasos sob condições de casa de vegetação. A suspensão da irrigação por 53 dias decresceu o conteúdo gravimétrico de água no solo e o potencial hídrico das folhas. O crescimento das plantas foi

  3. Response of Short Duration Tropical Legumes and Maize to Water Stress: A Glasshouse Study

    Directory of Open Access Journals (Sweden)

    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.

  4. Effects of drought stress condition on the yield of spring wheat ...

    African Journals Online (AJOL)

    Effects of drought stress condition on the yield of spring wheat ( Triticum aestivum ) lines. ... Drought stress tolerance is seen in almost all plants but its extent varies from species to species and even within species. ... from 32 Countries:.

  5. The role of mesophyll conductance during water stress and recovery in tobacco (Nicotiana sylvestris): acclimation or limitation?

    Science.gov (United States)

    Galle, Alexander; Florez-Sarasa, Igor; Tomas, Magdalena; Pou, Alicia; Medrano, Hipolito; Ribas-Carbo, Miquel; Flexas, Jaume

    2009-01-01

    While the responses of photosynthesis to water stress have been widely studied, acclimation to sustained water stress and recovery after re-watering is poorly understood. In particular, the factors limiting photosynthesis under these conditions, and their possible interactions with other environmental conditions, are unknown. To assess these issues, changes of photosynthetic CO(2) assimilation (A(N)) and its underlying limitations were followed during prolonged water stress and subsequent re-watering in tobacco (Nicotiana sylvestris) plants growing under three different climatic conditions: outdoors in summer, outdoors in spring, and indoors in a growth chamber. In particular, the regulation of stomatal conductance (g(s)), mesophyll conductance to CO(2) (g(m)), leaf photochemistry (chlorophyll fluorescence), and biochemistry (V(c,max)) were assessed. Leaf gas exchange and chlorophyll fluorescence data revealed that water stress induced a similar degree of stomatal closure and decreased A(N) under all three conditions, while V(c,max) was unaffected. However, the behaviour of g(m) differed depending on the climatic conditions. In outdoor plants, g(m) strongly declined with water stress, but it recovered rapidly (1-2 d) after re-watering in spring while it remained low many days after re-watering in summer. In indoor plants, g(m) initially declined with water stress, but then recovered to control values during the acclimation period. These differences were reflected in different velocities of recovery of A(N) after re-watering, being the slowest in outdoor summer plants and the fastest in indoor plants. It is suggested that these differences among the experiments are related to the prevailing climatic conditions, i.e. to the fact that stress factors other than water stress have been superimposed (e.g. excessive light and elevated temperature). In conclusion, besides g(s), g(m) contributes greatly to the limitation of photosynthesis during water stress and during

  6. 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.

  7. Mechanical stress analysis for a fuel rod under normal operating conditions

    International Nuclear Information System (INIS)

    Pino, Eddy S.; Giovedi, Claudia; Serra, Andre da Silva; Abe, Alfredo Y.

    2013-01-01

    Nuclear reactor fuel elements consist mainly in a system of a nuclear fuel encapsulated by a cladding material subject to high fluxes of energetic neutrons, high operating temperatures, pressure systems, thermal gradients, heat fluxes and with chemical compatibility with the reactor coolant. The design of a nuclear reactor requires, among a set of activities, the evaluation of the structural integrity of the fuel rod submitted to different loads acting on the fuel rod and the specific properties (dimensions and mechanical and thermal properties) of the cladding material and coolant, including thermal and pressure gradients produced inside the rod due to the fuel burnup. In this work were evaluated the structural mechanical stresses of a fuel rod using stainless steel as cladding material and UO 2 with a low degree of enrichment as fuel pellet on a PWR (pressurized water reactor) under normal operating conditions. In this sense, tangential, radial and axial stress on internal and external cladding surfaces considering the orientations of 0 deg, 90 deg and 180 deg were considered. The obtained values were compared with the limit values for stress to the studied material. From the obtained results, it was possible to conclude that, under the expected normal reactor operation conditions, the integrity of the fuel rod can be maintained. (author)

  8. Methods for evaluation of mechanical stress condition of materials

    Directory of Open Access Journals (Sweden)

    Mirchev Yordan

    2018-01-01

    Full Text Available Primary attention is given to the following methods: method by drilling cylindrical holes (drill method and integrated ultrasonic method using volume (longitudinal and transverse, surface, and sub-surface waves. Drill method allows determination of residual mechanical stress in small depth of material surfaces, assessing type, size, and orientation of principal stresses. For the first time, parallel studies are carried out of mechanical stress in materials using the electroacoustic effect of volume, surface and sub-surface waves on the one hand, and effective mechanical stresses on the other. The experimental results present electroacoustic coefficients for different types of waves in the material of gas pipeline tube of 243 mm diameter and 14 mm thickness. These are used to evaluate mechanical stresses in pipelines, according to active GOST standards.

  9. 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.

  10. 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)

  11. 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

  12. Effects of Azospirillum lipoferum on seedling characteristics derived from sunflower (Helianthus annus L. seed water deficit conditions

    Directory of Open Access Journals (Sweden)

    H. Hadi

    2016-05-01

    Full Text Available Seedling characteristics of different sunflower (Helianthus annus L. cultivars under drought stress and inoculation with the Azospirillum lipoferum in a spilt-factorial layout based on randomized complete block design with three replications were evaluated. Treatments included dehydration stress (seed produced on maternal plants which irrigated after 60 (desirable irrigation, 120 (medium stress, 180 mm (severe stress evaporation from evaporation pan class A, different sunflower cultivars (Lakomka, Master, Favorite, Soor and Armavirosky and inoculation with bacteria (Azospirillum lipoferum and control. Bacteria allocated in the main plots and seeds which derived from dehydration stress conditions and different cultivars were allocated in sub plots as a factorial layout. Results showed that the time of seedling emergence, seedling vigor index, leaf petiole, stem and seedling dry weight were increased 14, 44, 30, 31, 22 and 27 percent by inoculating with bacteria, respectively. The percent of Seedling emergence of seeds derived from medium stress 48 percent was more than optimal irrigation conditions. Final appearance, speed of emergence, emergence index, dry weight and stamina seedling resulting from severe stress conditions were decreased compared with optimal irrigation. Seedling emergence of seeds derived from medium stress which inoculated with bacteria increased by 9 percent. Emergence speed index, appearance, stamina and seedling dry weights of seeds which inoculated with bacteria increased at medium and sever water stress. With consideration of the effect of dehydration stress on germination and seedling emergence, seed inoculation with bacteria improved seedling emergence and seedling vigor of seeds derived from dehydration stress conditions.

  13. 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.

  14. Stress corrosion cracking of age-hardenable nickel-base alloys in LWR-conditions

    International Nuclear Information System (INIS)

    Kekkonen, T.; Haenninen, H.

    1985-01-01

    At present it seems that the microstructure most resistant to stress corrosion cracking (SCC) in high temperature water is obtained by a solution annealing treatment at a relatively high temperature (appr. 1100 deg C) followed by water quenching and a single aging treatment (appr. 700 deg C/20 h). This should produce a microstructure with a high M 23 Cc 6 :MC ratio, semi-continous coherent M 23 C 6 precipitation, and an evenly distributed gamma prime in the matrix. However, since the actual mechanism of SCC in age-hardenable Ni-base alloys is unclear, the microstructural features resulting in the good resistance to SCC cannot be specified. Furthermore, the possible microstructural changes caused by prolonged use in LWR-conditions are unknown

  15. Effects of Swim Stress on Neophobia and Reconditioning Using a Conditioned Taste Aversion Procedure

    Science.gov (United States)

    Walker, Jennifer M.; Ramsey, Ashley K.; Fowler, Stephanie W.; Schachtman, Todd R.

    2012-01-01

    Previous research has found that swim stress during a classical conditioning trial attenuates conditioned taste aversion (CTA). In the current study, rats were used to examine the effects of inescapable swim stress on the habituation of neophobia to a flavored solution and reacquisition of an extinguished conditioned taste aversion. In Experiment…

  16. 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

  17. Effect of silicon application on physiological characteristics and growth of wheat (Triticum aestivum L. under drought stress condition

    Directory of Open Access Journals (Sweden)

    A. Karmollachaab

    2016-05-01

    Full Text Available In order to investigate the effect of silicon application on some physiological characteristics and growth of Wheat (Triticum aestivum L. under late drought stress condition, an experiment was conducted at the Agriculture and Natural Resources University of Ramin, Khuzestan during year 2012. The experiment was conducted in the open environment as factorial randomized complete block design with three levels of drought stress (irrigation after 25, 50 and 75% depletion of available water content as the first factor and four levels of silicon (0, 10, 20 and 30 mg Si.kg-1 soil as the second factor with three replications. The results showed that drought stress imposed a negative significant effect on all traits. The drought stress led to increased electrolyte leakage and proline content, cuticular wax, leaf silicon concentration, superoxide dismutase activity (SOD and grain potassium were decreased. The severe drought stress has most effect on electrolyte leakage (up to 53%. The application of silicon except the shoot/root parameter, on all characters have been affected so that application of 30 mg Si.kg-1 soil led to decrease electrolyte leakage up to 22.5% and increased SOD activity, proline content, cuticular wax grain K and flag leaf Si concentration, 25, 12.8, 21, 17 and 30% compared to control, respectively. In general, the results showed a positive effect of silicon on wheat plant under stress conditions that were higher than no stress condition.

  18. Maize water status and physiological traits as affected by root endophytic fungus Piriformospora indica under combined drought and mechanical stresses.

    Science.gov (United States)

    Hosseini, Fatemeh; Mosaddeghi, Mohammad Reza; Dexter, Anthony Roger; Sepehri, Mozhgan

    2018-05-01

    Under combined drought and mechanical stresses, mechanical stress primarily controlled physiological responses of maize. Piriformospora indica mitigated the adverse effects of stresses, and inoculated maize experienced less oxidative damage and had better adaptation to stressful conditions. The objective of this study was to investigate the effect of maize root colonization by an endophytic fungus P. indica on plant water status, physiological traits and root morphology under combined drought and mechanical stresses. Seedlings of inoculated and non-inoculated maize (Zea mays L., cv. single cross 704) were cultivated in growth chambers filled with moistened siliceous sand at a matric suction of 20 hPa. Drought stress was induced using PEG 6000 solution with osmotic potentials of 0, - 0.3 and - 0.5 MPa. Mechanical stress (i.e., penetration resistances of 1.05, 4.23 and 6.34 MPa) was exerted by placing weights on the surface of the sand medium. After 30 days, leaf water potential (LWP) and relative water content (RWC), root and shoot fresh weights, root volume (RV) and diameter (RD), leaf proline content, leaf area (LA) and catalase (CAT) and ascorbate peroxidase (APX) activities were measured. The results show that exposure to individual drought and mechanical stresses led to higher RD and proline content and lower plant biomass, RV and LA. Moreover, increasing drought and mechanical stress severity increased APX activity by about 1.9- and 3.1-fold compared with the control. When plants were exposed to combined stresses, mechanical stress played the dominant role in controlling plant responses. P. indica-inoculated plants are better adapted to individual and combined stresses. The inoculated plants had greater RV, LA, RWC, LWP and proline content under stressful conditions. In comparison with non-inoculated plants, inoculated plants showed lower CAT and APX activities which means that they experienced less oxidative stress induced by stressful conditions.

  19. 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 ...

  20. 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.

  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.

    2013-01-01

    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

  2. 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.

  3. 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

  4. Physiological responses of Brassica napus to fulvic acid under water stress: Chlorophyll a fluorescence and antioxidant enzyme activity

    Directory of Open Access Journals (Sweden)

    Ramin Lotfi

    2015-10-01

    Full Text Available The ameliorative effect of fulvic acid (0, 300, and 600 mg L− 1 on photosystem II and antioxidant enzyme activity of the rapeseed (Brassica napus L. plant under water stress (60, 100, and 140 mm evaporation from class A pan was studied using split plots in a randomized complete block design with three replications. Results indicated that application of fulvic acid (FA improved the maximum quantum efficiency of PSII (Fv/Fm and performance index (PI of plants under both well-watered and limited-water conditions. The time span from Fo to Fm and the energy necessary for the closure of all reaction centers was significantly increased, but the size of the plastoquinone pool was reduced with increasing water stress levels. Plants treated with FA had higher peroxidase and catalase activities under all irrigation conditions. Activities of ascorbate peroxidase and superoxide dismutase in plants increased with increasing water stress. Malondialdehyde increased under severe water stress, but application of FA significantly decreased lipid peroxidation. Production of reactive oxygen species (ROS is a common phenomenon in plants under stress. Under this condition, the balance between the production of ROS and the quenching activity of antioxidants is upset, often resulting in oxidative damage. In this study, application of FA significantly increased fluorescence of chlorophyll a, inhibiting ROS production and enhancing antioxidant enzymes activity that destroyed ROS. Thus, ROS in plant cells was reduced under water stress by application of FA and consequently lipid peroxidation was reduced.

  5. Evaluation of Drought Stress Thresholds in Ornamental Barberry (Berberis thunbergii cv. Atropurpurea Shrub in Mashhad Condition

    Directory of Open Access Journals (Sweden)

    Reyhane Setayesh

    2017-08-01

    Full Text Available Introduction: The population growth and water requirement for domestic consumption, industry, agriculture and urban development in Mashhad megacity, increase pressures on freshwater resources. Therefore, planning for water use optimization is necessary. The new allocation of water resources for landscape greenish, especially in arid and semi-arid is difficult. Therefore, water allocation to landscape is valuable and should be used efficiently. According to water resource limitation, using drought-tolerant plant species and determine threshold of drought tolerance in landscape can improve water use management. Plants that naturally survive in your area are the ones best adapted to your soil, climate and rainfall. By selecting plants that either avoid or tolerate dry conditions, a beautiful, thriving landscape can be made possible. Drought-tolerant plants survive long periods of drought by storing water internally or by developing extensive root systems that sink deep into the soil. Many drought-tolerant plants have additional protection through a waxy coating that reduces evaporation or hairs on the leaf surface that reflect some of the light, insulating the plant. Most drought-tolerant plants use several of these features to survive on low amounts of precipitation. Japanese barberry is a compact woody deciduous shrub with arching branches. Leaf colours include green, bluish-green to dark red and purple. B. thunbergii's progress in the United States has, to date, been held in check to the south by, probably, its need for cold winter temperatures for stratification of the seeds, and to the west by, probably, drought conditions. Although very drought tolerant once established, a very dry terrain would tend to discourage its incursion. Rugged, adaptable, no serious problems or pests, easy to maintain, transplants readily, shade and drought tolerant, deer resistant is typical ad copy found at any site offering this shrub of colourful fall foliage. In

  6. Assessing water stress of desert vegetation using remote sensing : the case of the Tamarugo forest in the Atacama Desert (Northern Chile)

    NARCIS (Netherlands)

    Chávez Oyanadel, R.O.

    2014-01-01

    Water stress assessment of natural vegetation plays a key role in water management of desert ecosystems. It allows scientists and managers to relate water extraction rates to changes in vegetation water condition, and consequently to define safe water extraction rates for maintaining a healthy

  7. 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.

  8. Physiological Signals and Their Fractal Response to Stress Conditions, Environmental Changes and Neurodegenerative Diseases

    National Research Council Canada - National Science Library

    Scafetta, N; Moon, R. E; West, B. J

    2006-01-01

    .... Some of these studies have been intended to develop more reliable methodologies for understanding how biological systems respond to peculiar altered conditions induced by internal stress, environment...

  9. A Study on the Residual Stress Improvement of PWSCC(Primary Water Stress Corrosion Cracking) in DMW(Dissimilar Metal Weld)

    International Nuclear Information System (INIS)

    Kang, Sung Sik; Kim, Seok Hun; Lee, Seung Gun; Park, Heung Bae

    2010-01-01

    Since 2000s, most of the cracks are found in welds, especially in (DMW) dissimilar metal welds such as pressurizer safety relief nozzle, reactor head penetration, reactor bottom mounted instrumentation (BMI), and reactor nozzles. Even the cracks are revealed as a primary water stress corrosion cracking (PWSCC), it is difficult to find the cracks by current non destructive examination. The PWSCC is occurred by three incident factors, such as susceptible material, environmental corrosive condition, and welding residual stress. If one of the three factors can be erased or decreased, the PWSCC could be prevented. In this study, we performed residual stress analysis for DMW and several residual stress improvement methods. As the preventive methods of PWSCC, we used laser peening(IP) method, inlay weld(IW) method, and induction heating stress improvement(IHSI) method. The effect of residual stress improvement for preventive methods was compared and discussed by finite element modeling and residual stress of repaired DMW

  10. Flux Balance Analysis of Escherichia coli under Temperature and pH Stress Conditions

    KAUST Repository

    Xu, Xiaopeng

    2015-05-12

    An interesting discovery in biology is that most genes in an organism are dispensable. That means these genes have minor effects on survival of the organism in standard laboratory conditions. One explanation of this discovery is that some genes play important roles in specific conditions and are essential genes under those conditions. E. coli is a model organism, which is widely used. It can adapt to many stress conditions, including temperature, pH, osmotic, antibiotic, etc. Underlying mechanisms and associated genes of each stress condition responses are usually different. In our analysis, we combined protein abundance data and mutant conditional fitness data into E. coli constraint-based metabolic models to study conditionally essential metabolic genes under temperature and pH stress conditions. Flux Balance Analysis was employed as the modeling method to analysis these data. We discovered lists of metabolic genes, which are E. coli dispensable genes, but conditionally essential under some stress conditions. Among these conditionally essential genes, atpA in low pH stress and nhaA in high pH stress found experimental evidences from previous studies. Our study provides new conditionally essential gene candidates for biologists to explore stress condition mechanisms.

  11. 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.

  12. Combined effects of water stress and pollution on macroinvertebrate and fish assemblages in a Mediterranean intermittent river.

    Science.gov (United States)

    Kalogianni, Eleni; Vourka, Aikaterini; Karaouzas, Ioannis; Vardakas, Leonidas; Laschou, Sofia; Skoulikidis, Nikolaos Th

    2017-12-15

    Water stress is a key stressor in Mediterranean intermittent rivers exacerbating the negative effects of other stressors, such as pollutants, with multiple effects on different river biota. The current study aimed to determine the response of macroinvertebrate and fish assemblages to instream habitat and water chemistry, at the microhabitat scale and at different levels of water stress and pollution, in an intermittent Mediterranean river. Sampling was conducted at high and low summer discharge, at two consecutive years, and included four reaches that were targeted for their different levels of water stress and pollution. Overall, the macroinvertebrate fauna of Evrotas River indicated high resilience to intermittency, however, variation in community structure and composition occurred under acute water stress, due to habitat alteration and change in water physico-chemistry, i.e. water temperature increase. The combined effects of pollution and high water stress had, however, pronounced effects on species richness, abundance and community structure in the pollution impacted reach, where pollution sensitive taxa were almost extirpated. Fish response to drought, in reaches free of pollution, consisted of an increase in the abundance of the two small limnophilic species, coupled with their shift to faster flowing riffle habitats, and a reduction in the abundance of the larger, rheophilic species. In the pollution impacted reach, however, the combination of pollution and high water stress led to hypoxic conditions assumed to be the leading cause of the almost complete elimination of the fish assemblage. In contrast, the perennial Evrotas reaches with relatively stable physicochemical conditions, though affected hydrologically by drought, appear to function as refugia for fish during high water stress. When comparing the response of the two biotic groups to combined acute water stress and pollution, it is evident that macroinvertebrates were negatively impacted, but fish

  13. The Existing Regulatory Conditions for 'Energy Smart Water Utilities'

    DEFF Research Database (Denmark)

    Basse, Ellen Margrethe

    2014-01-01

    This chapter is focused on the legal conditions that exist for the energy–smart water utilities in the European Union (EU). In section 2 the interdependencies of water and energy services and the growing interest in solving these problems that may arise from this interdependence by regulatory ini...... legal design and the problems that it causes for the water utilities that want to be resource–efficient and have a low–carbon footprint.......This chapter is focused on the legal conditions that exist for the energy–smart water utilities in the European Union (EU). In section 2 the interdependencies of water and energy services and the growing interest in solving these problems that may arise from this interdependence by regulatory...... initiatives are shortly described. One of the solutions needed is a reduction of energy use in the water utilities by their utilisation of renewable sources – acting as energy–smart water utilities. Such utilities are described in section 3. The policy and law regulating the water utilities are important...

  14. Analytical and experimental investigation of chlorine decay in water supply systems under unsteady hydraulic conditions

    DEFF Research Database (Denmark)

    Aisopou, Angeliki; Stoianov, Ivan; Graham, Nigel

    2013-01-01

    This paper investigates the impact of the dynamic hydraulic conditions on the kinetics of chlorine decay in water supply systems. A simulation framework has been developed for the scale-adaptive hydraulic and chlorine decay modelling under steady- and unsteady-state flows. An unsteady decay coeff...... of experimental data provides new insights for the near real-time modelling and management of water quality as well as highlighting the uncertainty and challenges of accurately modelling the loss of disinfectant in water supply networks.......This paper investigates the impact of the dynamic hydraulic conditions on the kinetics of chlorine decay in water supply systems. A simulation framework has been developed for the scale-adaptive hydraulic and chlorine decay modelling under steady- and unsteady-state flows. An unsteady decay...... coefficient is defined which depends upon the absolute value of shear stress and the rate of change of shear stress for quasi-unsteady and unsteady-state flows. By coupling novel instrumentation technologies for continuous hydraulic monitoring and water quality sensors for in-pipe water quality sensing...

  15. Residual stress improvement in multi-layer welded plates using water-shower cooling during welding process

    International Nuclear Information System (INIS)

    Yanagida, Nobuyoshi; Koide, Hiroo

    2006-01-01

    To reduce tensile residual stress in a welded region, we developed a new welding method that applies a water-shower behind the welding torch. When this method is applied to welding of austenitic stainless steel plates, cooling conditions mainly determine how much the residual stress can be reduced. To determine the conditions, we first used FEM to evaluate the effects of interpass temperature on the residual stress. And we found effective conditions for reducing tensile residual stress. To verify the validity of the conditions, specimens welded with or without water shower cooling were manufactured. Residual stresses of the specimens were experimentally measured. It was found that tensile residual stresses were generated on the surface of the welds and those were reduced in the case that the water-shower was applied. These measurement results agree well with the FEM analyses. It can therefore be concluded that the water-shower cooling during welding is appropriate for reducing tensile residual stress in austenitic stainless steel welding. (author)

  16. 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.

  17. 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.

  18. 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

  19. 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

  20. Effects of sucrose concentration and water deprivation on Pavlovian conditioning and responding for conditioned reinforcement.

    Science.gov (United States)

    Tabbara, Rayane I; Maddux, Jean-Marie N; Beharry, Priscilla F; Iannuzzi, Jessica; Chaudhri, Nadia

    2016-04-01

    An appetitive Pavlovian conditioned stimulus (CS) can predict an unconditioned stimulus (US) and acquire incentive salience. We tested the hypothesis that US intensity and motivational state of the subject would influence Pavlovian learning and impact the attribution of incentive salience to an appetitive Pavlovian CS. To this end, we examined the effects of sucrose concentration and water deprivation on the acquisition of Pavlovian conditioning and responding for a conditioned reinforcer. Male Long-Evans rats (Harlan; 220-240 g) receiving 3% (3S) or 20% (20S) sucrose were either non-water deprived or given water for 1 hr per day. During Pavlovian conditioning sessions, half the rats in each concentration and deprivation condition received a 10-s CS paired with 0.2 ml of sucrose (16 trials/session; 3.2 ml/session). The remainder received unpaired CS and US presentations. Entries into a port where sucrose was delivered were recorded. Next, responding for conditioned reinforcement was tested, wherein pressing an active lever produced the CS and pressing an inactive lever had no consequences. CS-elicited port entries increased, and latency to the first CS-elicited port entry decreased across sessions in paired groups. Water deprivation augmented these effects, whereas sucrose concentration had no significant impact on behavior. Responding for conditioned reinforcement was observed in the 20S water-deprived, paired group. Thus, water deprivation can facilitate the acquisition of Pavlovian conditioning, potentially by enhancing motivational state, and a high-intensity US and a high motivational state can interact to heighten the attribution of incentive salience to an appetitive Pavlovian CS. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  1. Effect of Filter Cake on Physiological Traits and Ear Yield of Sweet Corn under Late Drought Stress Condition

    Directory of Open Access Journals (Sweden)

    aziz karmollachaab

    2017-10-01

    Full Text Available Introduction Environmental stresses are one of the main causes of severe yield reductions. Drought is still a serious agronomic problem and also one of the most important factors contributing to crop yield loss in arid and semi-arid areas in the world. Filter Cake is a byproduct of sugarcane industry and experiments on corn showed that the use of 20 tons per hectare Filter Cake increases crop productivity, total amount of dry matter, protein and forage yield compared with the control. Materials and methods This experiment was conducted at the Research Station of the Ramin Agricultural University of Khuzestan in 2012. The experiment was done as a split plot based on randomized complete block design with three replications. Drought stress at the end of the growth period in three levels, non-stress, mild and severe drought stress, respectively irrigated after 25, 50 and 75% depletion of available water, and was considered as the main factor. Drought stress was applied in early stage of the male inflorescence of plants to maturity for 35 days, due to the critical stage of the plant in late spring. Soil moisture was determined by gravimetric method. Different doses of Filter Cake (0, 10, 20 and 30 tons per hectare were considered as subplot factor and was added to the soil two days before the seeding. The final harvest as green corn was performed in the first phase of dough by hand in three times and two midfields of each subplot was considered as the margin of half a meter for each side. Finally, the data were analyzed using SAS 9.1 and means were compared by Duncan’s multiple range test at probability level of 5%. Results and discussion In non-stress conditions, Filter Cake is significantly increased plant height, So the amounts of 20 and 30 tons per hectare increased by 11.7% and 10.1% of the plant’s height, respectively, but the use of 10 tons of Filter Cake did not have a significant effect on it. In severe stress conditions, the use of

  2. Odors, Deployment Stress, and Health: A Conditioning Analysis of Gulf War Syndrome

    National Research Council Canada - National Science Library

    Dalton, Pamela

    2004-01-01

    .... The goal of this research is to investigate the extent to which people can acquire stress reactions as conditioned responses to odors and exhibit health symptoms as a result of such conditioning episodes...

  3. Odors, Deployment Stress, and Health: A Conditioning Analysis of Gulf War Syndrome

    National Research Council Canada - National Science Library

    Dalton, Pamela

    2005-01-01

    .... The goal of this research is to investigate the extent to which people can acquire stress reactions as conditioned responses to odors and exhibit health symptoms as a result of such conditioning episodes...

  4. Odors, Deployment Stress and Health: A Conditioning Analysis of Gulf War Syndrome

    National Research Council Canada - National Science Library

    Dalton, Pamela

    2006-01-01

    .... The goal of this research is to investigate the extent to which people can acquire stress reactions as conditioned responses to odors and exhibit health symptoms as a result of such conditioning episodes...

  5. Modelling soil water content variations under drought stress on soil column cropped with winter wheat

    Directory of Open Access Journals (Sweden)

    Csorba Szilveszter

    2014-12-01

    Full Text Available Mathematical models are effective tools for evaluating the impact of predicted climate change on agricultural production, but it is difficult to test their applicability to future weather conditions. We applied the SWAP model to assess its applicability to climate conditions, differing from those, for which the model was developed. We used a database obtained from a winter wheat drought stress experiment. Winter wheat was grown in six soil columns, three having optimal water supply (NS, while three were kept under drought-stressed conditions (S. The SWAP model was successfully calibrated against measured values of potential evapotranspiration (PET, potential evaporation (PE and total amount of water (TSW in the soil columns. The Nash-Sutcliffe model efficiency coefficient (N-S for TWS for the stressed columns was 0.92. For the NS treatment, we applied temporally variable soil hydraulic properties because of soil consolidation caused by regular irrigation. This approach improved the N-S values for the wetting-drying cycle from -1.77 to 0.54. We concluded that the model could be used for assessing the effects of climate change on soil water regime. Our results indicate that soil water balance studies should put more focus on the time variability of structuredependent soil properties.

  6. Generalized Unsafety Theory of Stress: Unsafe Environments and Conditions, and the Default Stress Response

    Directory of Open Access Journals (Sweden)

    Jos F. Brosschot

    2018-03-01

    Full Text Available Prolonged physiological stress responses form an important risk factor for disease. According to neurobiological and evolution-theoretical insights the stress response is a default response that is always “on” but inhibited by the prefrontal cortex when safety is perceived. Based on these insights the Generalized Unsafety Theory of Stress (GUTS states that prolonged stress responses are due to generalized and largely unconsciously perceived unsafety rather than stressors. This novel perspective necessitates a reconstruction of current stress theory, which we address in this paper. We discuss a variety of very common situations without stressors but with prolonged stress responses, that are not, or not likely to be caused by stressors, including loneliness, low social status, adult life after prenatal or early life adversity, lack of a natural environment, and less fit bodily states such as obesity or fatigue. We argue that in these situations the default stress response may be chronically disinhibited due to unconsciously perceived generalized unsafety. Also, in chronic stress situations such as work stress, the prolonged stress response may be mainly caused by perceived unsafety in stressor-free contexts. Thus, GUTS identifies and explains far more stress-related physiological activity that is responsible for disease and mortality than current stress theories.

  7. Generalized Unsafety Theory of Stress: Unsafe Environments and Conditions, and the Default Stress Response.

    Science.gov (United States)

    Brosschot, Jos F; Verkuil, Bart; Thayer, Julian F

    2018-03-07

    Prolonged physiological stress responses form an important risk factor for disease. According to neurobiological and evolution-theoretical insights the stress response is a default response that is always "on" but inhibited by the prefrontal cortex when safety is perceived. Based on these insights the Generalized Unsafety Theory of Stress (GUTS) states that prolonged stress responses are due to generalized and largely unconsciously perceived unsafety rather than stressors. This novel perspective necessitates a reconstruction of current stress theory, which we address in this paper. We discuss a variety of very common situations without stressors but with prolonged stress responses, that are not, or not likely to be caused by stressors, including loneliness, low social status, adult life after prenatal or early life adversity, lack of a natural environment, and less fit bodily states such as obesity or fatigue. We argue that in these situations the default stress response may be chronically disinhibited due to unconsciously perceived generalized unsafety. Also, in chronic stress situations such as work stress, the prolonged stress response may be mainly caused by perceived unsafety in stressor-free contexts. Thus, GUTS identifies and explains far more stress-related physiological activity that is responsible for disease and mortality than current stress theories.

  8. 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.

  9. 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.

  10. Cooling water conditioning and quality control for tokamaks

    International Nuclear Information System (INIS)

    Gootgeld, A.M.

    1995-01-01

    Designers and operators of Tokamaks and all associated water cooled, peripheral equipment, are faced with the task of providing and maintaining closed-loop, low conductivity, low impurity, cooling water systems. The primary reason for supplying low conductivity water to the DIII-D vacuum vessel coils, power supplies and auxiliary heating components is to assure, along with the use of a non-conducting break in the supply piping, sufficient electrical resistance and thus an acceptable current-leakage path to ground at operating voltage potentials. As important, good quality cooling water significantly reduces the likelihood of scaling and fouling of flow passages and heat transfer surfaces. Dissolved oxygen gas removal is also required in one major DIII-D cooling water system to minimize corrosion in the ion sources of the neutral beam injectors. Currently, the combined pumping capacity of the high quality cooling water systems at DIII-D is ∼5,000 gpm. Another area that receives close attention at DIII-D is the chemical treatment of the water used in the cooling towers. This paper discusses the DIII-D water quality requirements, the means used to obtain the necessary quality and the instrumentation used for control and monitoring. Costs to mechanically and chemically condition and maintain water quality are discussed as well as the various aspects of complying with government standards and regulations

  11. Stability of niclosamide in water under local conditions

    International Nuclear Information System (INIS)

    El Hindi, A.M.; Sidra, M.S.

    1986-01-01

    The stability of 14 C-labelled niclosamide was studied in distilled water at two different pH values and in canal water. 2 mg/1 niclosamide solutions were exposed to direct atmospheric conditions. The activity was followed by radioassay and the concentration of niclosamide was determined by GLC. The total activity was found to decrease to 46.0% in weakly acidic solution (pH 6.5), 45% in neutral solution (pH 7.0) and 16.7% in filtered canal water after three weeks. GLC analysis showed that niclosamide concentration had dropped to 0.05, 0.06 and 0.03 mg/1 in weakly acidic, neutral medium and canal water after the same period. GLC analysis as compared to radioassay indicated the presence of increasing amounts of degradation product(s), in the chloroform extracts of water with time, which were not detected by GLC

  12. Cooling water conditioning and quality control for tokamaks

    International Nuclear Information System (INIS)

    Gootgeld, A.M.

    1995-10-01

    Designers and operators of Tokamaks and all associated water cooled, peripheral equipment, are faced with the task of providing and maintaining closed-loop, low conductivity, low impurity, cooling water systems. Most of these systems must provide large volumes of high quality cooling water at reasonable cost and comply with local and state government orders and EPA mandated national pretreatment standards and regulations. This paper discusses the DIII-D water quality requirements, the means used to obtain the necessary quality and the instrumentation used for control and monitoring. Costs to mechanically and chemically condition and maintain water quality are discussed as well as the various aspects of complying with government standards and regulations

  13. Foliar nitrogen and potassium applications improve photosynthetic activities and water relations in sunflower under moisture deficit condition

    International Nuclear Information System (INIS)

    Hussain, R.A.; Ahmad, R.

    2016-01-01

    This study investigated the influence of foliar supplementation of nitrogen (N) potassium (K) and their combination on photosynthetic activities, physiological indices and water relations of two sunflower (Helianthus annuus L.) hybrids Hysen-33 and LG-5551 under water deficit condition. Studies were conducted in a wire-house at Nuclear Institute for Agriculture and Biology, Faisalabad, Pakistan. Treatments were two water stress levels [100 (control) and 60% field capacity (water deficit)], six levels of foliar spray (no spray, water spray, 1% N, 1% K, 0.5% N + 0.5% K and 1% N + 1% K) and each treatment was replicated three times. Results showed that water stress reduced the photosynthetic activities: Pn (photosynthetic rate), E (rate of tanspiration) and gs (stomatal conductance) and water relations i.e., pie w (water potential), pie s (osmotic potential) and pie p (turgor potential) . Soil moisture deficit also significantly reduced the plant height, root length, fresh and dry matter which consequently affected the plant height stress tolerance index (PHSI), root length stress tolerance index (RLSI) and dry matter stress tolerance index (DMSI) in both sunflower hybrids. However, foliar supplementation with N and K or N+K improved the photosynthetic activities, water relations and physiological indices of both the sunflower hybrids. The findings of present study suggest that application of N+K is necessary to have high plant productivity. (author)

  14. Validation of reference genes from Eucalyptus spp. under different stress conditions

    Directory of Open Access Journals (Sweden)

    Moura Jullyana Cristina Magalhães Silva

    2012-11-01

    Full Text Available Abstract Background The genus Eucalyptus consists of approximately 600 species and subspecies and has a physiological plasticity that allows some species to propagate in different regions of the world. Eucalyptus is a major source of cellulose for paper manufacturing, and its cultivation is limited by weather conditions, particularly water stress and low temperatures. Gene expression studies using quantitative reverse transcription polymerase chain reaction (qPCR require reference genes, which must have stable expression to facilitate the comparison of the results from analyses using different species, tissues, and treatments. Such studies have been limited in eucalyptus. Results Eucalyptus globulus Labill, Eucalyptus urograndis (hybrid from Eucalyptus urophylla S.T. Blake X Eucalyptus grandis Hill ex-Maiden and E. uroglobulus (hybrid from E. urograndis X E. globulus were subjected to different treatments, including water deficiency and stress recovery, low temperatures, presence or absence of light, and their respective controls. Except for treatment with light, which examined the seedling hypocotyl or apical portion of the stem, the expression analyses were conducted in the apical and basal parts of the stem. To select the best pair of genes, the bioinformatics tools GeNorm and NormFinder were compared. Comprehensive analyses that did not differentiate between species, treatments, or tissue types, showed that IDH (isocitrate dehydrogenase, SAND (SAND protein, ACT (actin, and A-Tub (α-tubulin genes were the most stable. IDH was the most stable gene in all of the treatments. Conclusion Comparing these results with those of other studies on eucalyptus, we concluded that five genes are stable in different species and experimental conditions: IDH, SAND, ACT, A-Tub, and UBQ (ubiquitin. It is usually recommended a minimum of two reference genes is expression analysis; therefore, we propose that IDH and two others genes among the five identified

  15. Method for accelerated aging under combined environmental stress conditions

    International Nuclear Information System (INIS)

    Gillen, K.T.

    1979-01-01

    An accelerated aging method which can be used to simulate aging in combined stress environment situations is described. It is shown how the assumptions of the method can be tested experimentally. Aging data for a chloroprene cable jacketing material in single and combined radiation and temperature environments are analyzed and it is shown that these data offer evidence for the validity of the method

  16. Association between neuroticism and amygdala responsivity emerges under stressful conditions

    NARCIS (Netherlands)

    Everaerd, Daphne; Klumpers, Floris; van Wingen, Guido; Tendolkar, Indira; Fernández, Guillén

    2015-01-01

    Increased amygdala reactivity in response to salient stimuli is seen in patients with affective disorders, in healthy subjects at risk for these disorders, and in stressed individuals, making it a prime target for mechanistic studies into the pathophysiology of affective disorders. However, whereas

  17. Conditions for low stress-risk jobs: Europe's case

    NARCIS (Netherlands)

    Oeij, P.R.A.; Dhondt, S.; Wiezer, N.

    2006-01-01

    The European situation of new forms of work organisation and stress risks in jobs are described against the ‘decentralisationhuman factor orientation model’, which discerns types of work organisation. ‘Flexible firms’ based on lean production have the highest probability of high strain jobs,

  18. Enhancing water stress tolerance improves fitness in biological control strains of Lactobacillus plantarum in plant environments.

    Science.gov (United States)

    Daranas, Núria; Badosa, Esther; Francés, Jesús; Montesinos, Emilio; Bonaterra, Anna

    2018-01-01

    Lactobacillus plantarum strains PM411 and TC92 can efficiently control bacterial plant diseases, but their fitness on the plant surface is limited under unfavourable low relative humidity (RH) conditions. To increase tolerance of these strains to water stress, an adaptive strategy was used consisting of hyperosmotic and acidic conditions during growth. Adapted cells had higher survival rates under desiccation than non-adapted cells. Transcript levels and patterns of general stress-related genes increased immediately after the combined-stress adaptation treatment, and remained unaltered or repressed during the desiccation challenge. However, there were differences between strains in the transcription patterns that were in agreement with a better performance of adapted cells of PM411 than TC92 in plant surfaces under low RH environmental conditions. The combined-stress adaptation treatment increased the survival of PM411 cells consistently in different plant hosts in the greenhouse and under field conditions. Stress-adapted cells of PM411 had similar biocontrol potential against bacterial plant pathogens than non-adapted cells, but with less variability within experiments.

  19. Enhancing water stress tolerance improves fitness in biological control strains of Lactobacillus plantarum in plant environments.

    Directory of Open Access Journals (Sweden)

    Núria Daranas

    Full Text Available Lactobacillus plantarum strains PM411 and TC92 can efficiently control bacterial plant diseases, but their fitness on the plant surface is limited under unfavourable low relative humidity (RH conditions. To increase tolerance of these strains to water stress, an adaptive strategy was used consisting of hyperosmotic and acidic conditions during growth. Adapted cells had higher survival rates under desiccation than non-adapted cells. Transcript levels and patterns of general stress-related genes increased immediately after the combined-stress adaptation treatment, and remained unaltered or repressed during the desiccation challenge. However, there were differences between strains in the transcription patterns that were in agreement with a better performance of adapted cells of PM411 than TC92 in plant surfaces under low RH environmental conditions. The combined-stress adaptation treatment increased the survival of PM411 cells consistently in different plant hosts in the greenhouse and under field conditions. Stress-adapted cells of PM411 had similar biocontrol potential against bacterial plant pathogens than non-adapted cells, but with less variability within experiments.

  20. Compositions and methods for providing plants with tolerance to abiotic stress conditions

    KAUST Repository

    Hirt, Heribert

    2017-07-27

    It has been discovered that the desert endophytic bacterium SA187 SA187 can provide resistance or tolerance to abiotic stress conditions to seeds or plants. Compositions containing SA187 can be used to enhance plant development and yield under environmental stress conditions.

  1. Influence of arbuscular mycorrhizae on biomass production and nitrogen fixation of berseem clover plants subjected to water stress.

    Directory of Open Access Journals (Sweden)

    Sergio Saia

    Full Text Available Several studies, performed mainly in pots, have shown that arbuscular mycorrhizal symbiosis can mitigate the negative effects of water stress on plant growth. No information is available about the effects of arbuscular mycorrhizal symbiosis on berseem clover growth and nitrogen (N fixation under conditions of water shortage. A field experiment was conducted in a hilly area of inner Sicily, Italy, to determine whether symbiosis with AM fungi can mitigate the detrimental effects of drought stress (which in the Mediterranean often occurs during the late period of the growing season on forage yield and symbiotic N2 fixation of berseem clover. Soil was either left under water stress (i.e., rain-fed conditions or the crop was well-watered. Mycorrhization treatments consisted of inoculation of berseem clover seeds with arbuscular mycorrhizal spores or suppression of arbuscular mycorrhizal symbiosis by means of fungicide treatments. Nitrogen biological fixation was assessed using the 15N-isotope dilution technique. Arbuscular mycorrhizal symbiosis was able to mitigate the negative effect of water stress on berseem clover grown in a typical semiarid Mediterranean environment. In fact, under water stress conditions, arbuscular mycorrhizal symbiosis resulted in increases in total biomass, N content, and N fixation, whereas no effect of crop mycorrhization was observed in the well-watered treatment.

  2. Influence of arbuscular mycorrhizae on biomass production and nitrogen fixation of berseem clover plants subjected to water stress.

    Science.gov (United States)

    Saia, Sergio; Amato, Gaetano; Frenda, Alfonso Salvatore; Giambalvo, Dario; Ruisi, Paolo

    2014-01-01

    Several studies, performed mainly in pots, have shown that arbuscular mycorrhizal symbiosis can mitigate the negative effects of water stress on plant growth. No information is available about the effects of arbuscular mycorrhizal symbiosis on berseem clover growth and nitrogen (N) fixation under conditions of water shortage. A field experiment was conducted in a hilly area of inner Sicily, Italy, to determine whether symbiosis with AM fungi can mitigate the detrimental effects of drought stress (which in the Mediterranean often occurs during the late period of the growing season) on forage yield and symbiotic N2 fixation of berseem clover. Soil was either left under water stress (i.e., rain-fed conditions) or the crop was well-watered. Mycorrhization treatments consisted of inoculation of berseem clover seeds with arbuscular mycorrhizal spores or suppression of arbuscular mycorrhizal symbiosis by means of fungicide treatments. Nitrogen biological fixation was assessed using the 15N-isotope dilution technique. Arbuscular mycorrhizal symbiosis was able to mitigate the negative effect of water stress on berseem clover grown in a typical semiarid Mediterranean environment. In fact, under water stress conditions, arbuscular mycorrhizal symbiosis resulted in increases in total biomass, N content, and N fixation, whereas no effect of crop mycorrhization was observed in the well-watered treatment.

  3. A Root water uptake model to compensate disease stress in citrus trees

    Science.gov (United States)

    Peddinti, S. R.; Kambhammettu, B. P.; Lad, R. S.; Suradhaniwar, S.

    2017-12-01

    Plant root water uptake (RWU) controls a number of hydrologic fluxes in simulating unsaturated flow and transport processes. Variable saturated models that simulate soil-water-plant interactions within the rizhosphere do not account for the health of the tree. This makes them difficult to analyse RWU patterns for diseased trees. Improper irrigation management activities on diseased (Phytopthora spp. affected) citrus trees of central India has resulted in a significant reduction in crop yield accompanied by disease escalation. This research aims at developing a quantitative RWU model that accounts for the reduction in water stress as a function of plant disease level (hereafter called as disease stress). A total of four research plots with varying disease severity were considered for our field experimentation. A three-dimensional electrical resistivity tomography (ERT) was performed to understand spatio-temporal distribution in soil moisture following irrigation. Evaporation and transpiration were monitored daily using micro lysimeter and sap flow meters respectively. Disease intensity was quantified (on 0 to 9 scale) using pathological analysis on soil samples. Pedo-physocal and pedo-electric relations were established under controlled laboratory conditions. A non-linear disease stress response function for citrus trees was derived considering phonological, hydrological, and pathological parameters. Results of numerical simulations conclude that the propagation of error in RWU estimates by ignoring the health condition of the tree is significant. The developed disease stress function was then validated in the presence of deficit water and nutrient stress conditions. Results of numerical analysis showed a good agreement with experimental data, corroborating the need for alternate management practices for disease citrus trees.

  4. 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

  5. Stress corrosion of low alloy steels used in external bolting on pressurised water reactors

    International Nuclear Information System (INIS)

    Skeldon, P.; Hurst, P.; Smart, N.R.

    1992-01-01

    The stress corrosion cracking (SCC) susceptibility of AISI 4140 and AISI 4340 steels has been evaluated in five environments, three simulating a leaking aqueous boric acid environment and two simulating ambient external conditions ie moist air and salt spray. Both steels were found to be highly susceptible to SCC in all environments at hardnesses of 400 VPN and above. The susceptibility was greatly reduced at hardnesses below 330 VPN but in one environment, viz refluxing PWR primary water, SCC was observed at hardnesses as low as 260VPN. Threshold stress intensities for SCC were frequently lower than those in the literature

  6. Assessing the effects of adaptation measures on optimal water resources allocation under varied water availability conditions

    Science.gov (United States)

    Liu, Dedi; Guo, Shenglian; Shao, Quanxi; Liu, Pan; Xiong, Lihua; Wang, Le; Hong, Xingjun; Xu, Yao; Wang, Zhaoli

    2018-01-01

    Human activities and climate change have altered the spatial and temporal distribution of water availability which is a principal prerequisite for allocation of different water resources. In order to quantify the impacts of climate change and human activities on water availability and optimal allocation of water resources, hydrological models and optimal water resource allocation models should be integrated. Given that increasing human water demand and varying water availability conditions necessitate adaptation measures, we propose a framework to assess the effects of these measures on optimal allocation of water resources. The proposed model and framework were applied to a case study of the middle and lower reaches of the Hanjiang River Basin in China. Two representative concentration pathway (RCP) scenarios (RCP2.6 and RCP4.5) were employed to project future climate, and the Variable Infiltration Capacity (VIC) hydrological model was used to simulate the variability of flows under historical (1956-2011) and future (2012-2099) conditions. The water availability determined by simulating flow with the VIC hydrological model was used to establish the optimal water resources allocation model. The allocation results were derived under an extremely dry year (with an annual average water flow frequency of 95%), a very dry year (with an annual average water flow frequency of 90%), a dry year (with an annual average water flow frequency of 75%), and a normal year (with an annual average water flow frequency of 50%) during historical and future periods. The results show that the total available water resources in the study area and the inflow of the Danjiangkou Reservoir will increase in the future. However, the uneven distribution of water availability will cause water shortage problems, especially in the boundary areas. The effects of adaptation measures, including water saving, and dynamic control of flood limiting water levels (FLWLs) for reservoir operation, were

  7. Water Stress Affects Development Time but Not Takeoff Performance in the Butterfly Pararge aegeria.

    Science.gov (United States)

    Lailvaux, Simon P; Breuker, Casper J; Van Damme, Raoul

    Most organisms are limited in the amount and type of resources they are able to extract from the environment. The juvenile environment is particularly important in this regard, as conditions over ontogeny can influence the adult phenotype. Whole-organism performance traits, such as locomotion, are susceptible to such environmental effects, yet the specific biotic and abiotic factors driving performance plasticity have received little attention. We tested whether speckled wood Pararge aegeria L. butterflies reared under conditions of water stress exhibited poorer flight morphology and performance than control individuals. Despite large differences in mortality between treatments, we found no effects of water stress treatment on takeoff performance and only minor treatment effects on flight morphology. However, butterflies reared on water-stressed diets exhibited both significantly greater mortality and longer development times than did control individuals. Pararge aegeria larvae may compensate for this stress by prolonging development, resulting in similar realized performance capacities at least in takeoff performance in surviving adult butterflies; other measures of flight performance remain to be considered. Alternatively, the adult phenotype may be insulated from environmental effects at the larval stage in these insects.

  8. 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.

  9. Carbon-13 discrimination as a criterion for identifying high water use efficiency wheat cultivars under water deficit conditions

    International Nuclear Information System (INIS)

    Bazza, M.

    1996-01-01

    During four consecutive years, 20 durum wheat (Triticum durum Desf) and bread wheat (Triticum aestrivum L.) cultivars were grown under rain-fed conditions and supplementary irrigation with the objective of assessing the possibility of using 13 C discrimination Δ as a criterion to screen for wheat cultivars that produce high yields and have a better water use efficiency under water deficit conditions. In all four growing season, both treatments were subjected to some water stress which was higher under rain-fed conditions and varied according to the intensity and time of rainfall. During the first growing season, and despite small differences between the two treatments in terms of the amounts of water used, the grain and straw yields as well as Δ were significantly higher in the treatment which received an irrigation at installation than in the one without irrigation. There was substantial genotypic variation in Δ. When both treatments were considered, the total above ground dry matter yield and grain yield were positively correlated with Δ although the correlation coefficient of grain yield versus Δ was not high ( ** ). The data suggest that while a high Δ value may be used as a criterion for selection of cultivars of wheat with potential for high yield and high water use efficiency in wheat under field conditions, caution must be exercised in the selection process as the size of the canopy and the changes in environmental factors mainly soil water content, can result in changes in Δ and the yield of a cultivar. However, Δ of a genotype can also provide valuable information with respect to plant parameters responsible for the control of Δ and this information can be usefully employed in breeding programmes aimed at developing wheat cultivars high in yield and high in water use efficiency, and suitable for cultivation in arid and semi-arid regions of the tropics and sub-tropics. 11 refs, 2 figs, 2 tabs

  10. Carbon-13 discrimination as a criterion for identifying high water use efficiency wheat cultivars under water deficit conditions

    Energy Technology Data Exchange (ETDEWEB)

    Bazza, M [Rabat-Institus, Rabat (Morocco). Inst. Agronomique et Veterinaire Hassan II

    1996-07-01

    During four consecutive years, 20 durum wheat (Triticum durum Desf) and bread wheat (Triticum aestrivum L.) cultivars were grown under rain-fed conditions and supplementary irrigation with the objective of assessing the possibility of using {sup 13}C discrimination {Delta} as a criterion to screen for wheat cultivars that produce high yields and have a better water use efficiency under water deficit conditions. In all four growing season, both treatments were subjected to some water stress which was higher under rain-fed conditions and varied according to the intensity and time of rainfall. During the first growing season, and despite small differences between the two treatments in terms of the amounts of water used, the grain and straw yields as well as {Delta} were significantly higher in the treatment which received an irrigation at installation than in the one without irrigation. There was substantial genotypic variation in {Delta}. When both treatments were considered, the total above ground dry matter yield and grain yield were positively correlated with {Delta} although the correlation coefficient of grain yield versus {Delta} was not high (< 0.45{sup **}). The data suggest that while a high {Delta} value may be used as a criterion for selection of cultivars of wheat with potential for high yield and high water use efficiency in wheat under field conditions, caution must be exercised in the selection process as the size of the canopy and the changes in environmental factors mainly soil water content, can result in changes in {Delta} and the yield of a cultivar. But, {Delta} of a genotype can also provide valuable information with respect to plant parameters responsible for the control of {Delta} and this information can be usefully employed in breeding programmes aimed at developing wheat cultivars high in yield and high in water use efficiency, and suitable for cultivation in arid and semi-arid regions of the tropics and sub-tropics. 11 refs,2figs,2tabs.

  11. 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

  12. 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

  13. 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)

  14. Increased cesium uptake by water tupelo under inundated conditions

    International Nuclear Information System (INIS)

    McLeod, K.W.

    1980-01-01

    Low level releases of 137 Cs to streams has resulted in concentrations greater than background levels in soils, sediments and plants of the Savannah River swamp. The object of this study was to determine the effect of inundation on the absorption of 137 Cs by water tupelo (Nyssa aquatica) which is dominant in the swamp and is able to survive and grow well under flooded conditions. Results show that actively growing young water tupelo absorb about twice as much 137 Cs when grown in the laboratory under inundated conditions suggesting that in the spring, when inundated conditions usually exist and rapid growth occurs, uptake of 137 Cs is high. Some Cs is transported from soil depths and returned to soil surface via incorporation into leaves and subsequent leaf fall, thus continually mixing Cs which was buried below the soil surface. (U.K.)

  15. Evaluation of sorghum genotypes under drought stress conditions ...

    African Journals Online (AJOL)

    Seven genotypes of sorghum (Sorghum bicolour (L.) Moench) were studied in both drought and normal conditions. In each condition, the genotypes were evaluated using a split plot based randomized complete block design with three replications. Drought tolerance indices including stability tolerance index (STI), mean ...

  16. Effectiveness of the application of arbuscular mycorrhiza fungi and organic amendments to improve soil quality and plant performance under stress conditions

    NARCIS (Netherlands)

    Azcón, R.; Medina, A.

    2010-01-01

    Plant growth is limited in arid and/or contaminated sites due to the adverse conditions coming from heavy metal (HM) contamination and/or water stress. Moreover, soils from these areas are generally characterised by poor soil structure, low water-holding capacity, lack of organic matter and nutrient

  17. Survival and weight change among adult individuals of Periplaneta americana (Linnaeus, 1758 (Blattaria, Blattidae subject to various stress conditions

    Directory of Open Access Journals (Sweden)

    Jucelio Peter Duarte

    2015-05-01

    Full Text Available Periplaneta americana is a species of great importance to public health, since it can act as a vector of many pathogens and it reaches large populations in urban environments. This is probably due to its ability to resist starvation and desiccation. This study aimed to evaluate the effects of absence of water and food on survival and weight change among adult P. americana individuals and check whether the initial weight of individuals influences on their survival. Four groups having twenty P. americana couples were formed and subject to: I no water or food; II no food; III no water; and IV control group. Insects were isolated according to the groups, which were weighed at the beginning and end of the stress conditions. They remained under these conditions until all individuals in each test group were dead. Stress conditions caused reduction in survival time when compared to the control group. Adults with higher body mass survived longer when deprived only of food, while among those lacking water, weight had no influence on survival. Total weight loss was greater among individuals deprived of water than those deprived only of food.

  18. Survival and weight change among adult individuals of Periplaneta americana (Linnaeus, 1758 (Blattaria, Blattidae subject to various stress conditions

    Directory of Open Access Journals (Sweden)

    Jucelio Peter Duarte

    2015-03-01

    Full Text Available http://dx.doi.org/10.5007/2175-7925.2015v28n2p103 Periplaneta americana is a species of great importance to public health, since it can act as a vector of many pathogens and it reaches large populations in urban environments. This is probably due to its ability to resist starvation and desiccation. This study aimed to evaluate the effects of absence of water and food on survival and weight change among adult P. americana individuals and check whether the initial weight of individuals influences on their survival. Four groups having twenty P. americana couples were formed and subject to: I no water or food; II no food; III no water; and IV control group. Insects were isolated according to the groups, which were weighed at the beginning and end of the stress conditions. They remained under these conditions until all individuals in each test group were dead. Stress conditions caused reduction in survival time when compared to the control group. Adults with higher body mass survived longer when deprived only of food, while among those lacking water, weight had no influence on survival. Total weight loss was greater among individuals deprived of water than those deprived only of food.

  19. Early fasting is long lasting: differences in early nutritional conditions reappear under stressful conditions in adult female zebra finches.

    Directory of Open Access Journals (Sweden)

    E Tobias Krause

    Full Text Available Conditions experienced during early life can have profound effects on individual development and condition in adulthood. Differences in nutritional provisioning in birds during the first month of life can lead to differences in growth, reproductive success and survival. Yet, under natural conditions shorter periods of nutritional stress will be more prevalent. Individuals may respond differently, depending on the period of development during which nutritional stress was experienced. Such differences may surface specifically when poor environmental conditions challenge individuals again as adults. Here, we investigated long term consequences of differences in nutritional conditions experienced during different periods of early development by female zebra finches (Taeniopygia guttata on measures of management and acquisition of body reserves. As nestlings or fledglings, subjects were raised under different nutritional conditions, a low or high quality diet. After subjects reached sexual maturity, we measured their sensitivity to periods of food restriction, their exploration and foraging behaviour as well as adult resting metabolic rate (RMR. During a short period of food restriction, subjects from the poor nutritional conditions had a higher body mass loss than those raised under qualitatively superior nutritional conditions. Moreover, subjects that were raised under poor nutritional conditions were faster to engage in exploratory and foraging behaviour. But RMR did not differ among treatments. These results reveal that early nutritional conditions affect adult exploratory behaviour, a representative personality trait, foraging and adult's physiological condition. As early nutritional conditions are reflected in adult phenotypic plasticity specifically when stressful situations reappear, the results suggest that costs for poor developmental conditions are paid when environmental conditions deteriorate.

  20. Wine grape cultivar influence on the performance of models that predict the lower threshold canopy temperature of a water stress index

    Science.gov (United States)

    The calculation of a thermal based Crop Water Stress Index (CWSI) requires an estimate of canopy temperature under non-water stressed conditions. The objective of this study was to assess the influence of different wine grape cultivars on the performance of models that predict canopy temperature non...

  1. Genome-wide identification of differentially expressed genes under water deficit stress in upland cotton (Gossypium hirsutum L.).

    Science.gov (United States)

    Park, Wonkeun; Scheffler, Brian E; Bauer, Philip J; Campbell, B Todd

    2012-06-15

    Cotton is the world's primary fiber crop and is a major agricultural commodity in over 30 countries. Like many other global commodities, sustainable cotton production is challenged by restricted natural resources. In response to the anticipated increase of agricultural water demand, a major research direction involves developing crops that use less water or that use water more efficiently. In this study, our objective was to identify differentially expressed genes in response to water deficit stress in cotton. A global expression analysis using cDNA-Amplified Fragment Length Polymorphism was conducted to compare root and leaf gene expression profiles from a putative drought resistant cotton cultivar grown under water deficit stressed and well watered field conditions. We identified a total of 519 differentially expressed transcript derived fragments. Of these, 147 transcript derived fragment sequences were functionally annotated according to their gene ontology. Nearly 70 percent of transcript derived fragments belonged to four major categories: 1) unclassified, 2) stress/defense, 3) metabolism, and 4) gene regulation. We found heat shock protein-related and reactive oxygen species-related transcript derived fragments to be among the major parts of functional pathways induced by water deficit stress. Also, twelve novel transcripts were identified as both water deficit responsive and cotton specific. A subset of differentially expressed transcript derived fragments was verified using reverse transcription-polymerase chain reaction. Differential expression analysis also identified five pairs of duplicated transcript derived fragments in which four pairs responded differentially between each of their two homologues under water deficit stress. In this study, we detected differentially expressed transcript derived fragments from water deficit stressed root and leaf tissues in tetraploid cotton and provided their gene ontology, functional/biological distribution, and

  2. Fault condition stress analysis of NET 16 TF coil model

    International Nuclear Information System (INIS)

    Jong, C.T.J.

    1992-04-01

    As part of the design process of the NET/ITER toroidal field coils (TFCs), the mechanical behaviour of the magnetic system under fault conditions has to be analysed in some detail. Under fault conditions, either electrical or mechanical, the magnetic loading of the coils becomes extreme and further mechanical failure of parts of the overall structure might occur (e.g. failure of the coil, gravitational support, intercoil structure). The mechanical behaviour of the magnetic system under fault conditions has been analysed with a finite element model of the complete TFC system. The analysed fault conditions consist of: a thermal fault, electrical faults and mechanical faults. The mechanical faults have been applied simultaneously with an electrical fault. This report described the work carried out to create the finite element model of 16 TFCs and contains an extensive presentation of the results, obtained with this model, of a normal operating condition analysis and 9 fault condition analyses. Chapter 2-5 contains a detailed description of the finite element model, boundary conditions and loading conditions of the analyses made. Chapters 2-4 can be skipped if the reader is only interested in results. To understand the results presented chapter 6 is recommended, which contains a detailed description of all analysed fault conditions. The dimensions and geometry of the model correspond to the status of the NET/ITER TFC design of May 1990. Compared with previous models of the complete magnetic system, the finite element model of 16 TFCs is 'detailed', and can be used for linear elastic analysis with faulted loads. (author). 8 refs.; 204 figs.; 134 tabs

  3. Assessing Maize Foliar Water Stress Levels Under Field Conditions ...

    African Journals Online (AJOL)

    spectroscopy with its numerous fine wavelengths and is non-destructive to .... outcomes (Zhang et al., 2012) whereas others previously realized only the .... in the leaf structure also accounts for the visualised difference around the NIR region.

  4. Characterization of the Symbiotic Nitrogen-Fixing Common Bean Low Phytic Acid (lpa1) Mutant Response to Water Stress.

    Science.gov (United States)

    Chiozzotto, Remo; Ramírez, Mario; Talbi, Chouhra; Cominelli, Eleonora; Girard, Lourdes; Sparvoli, Francesca; Hernández, Georgina

    2018-02-15

    The common bean ( Phaseolus vulgaris L.) low phytic acid ( lpa1 ) biofortified genotype produces seeds with improved nutritional characteristics and does not display negative pleiotropic effects. Here we demonstrated that lpa1 plants establish an efficient nitrogen-fixing symbiosis with Rhizobium etli CE3. The lpa1 nodules showed a higher expression of nodule-function related genes than the nodules of the parental wild type genotype (BAT 93). We analyzed the response to water stress of lpa1 vs. BAT 93 plants grown under fertilized or under symbiotic N₂-fixation conditions. Water stress was induced by water withholding (up to 14% soil moisture) to fertilized or R. etli nodulated plants previously grown with normal irrigation. The fertilized lpa1 plants showed milder water stress symptoms during the water deployment period and after the rehydration recovery period when lpa1 plants showed less biomass reduction. The symbiotic water-stressed lpa1 plants showed decreased nitrogenase activity that coincides with decreased sucrose synthase gene expression in nodules; lower turgor weight to dry weight (DW) ratio, which has been associated with higher drought resistance index; downregulation of carbon/nitrogen (C/N)-related and upregulation of stress-related genes. Higher expression of stress-related genes was also observed in bacteroids of stressed lpa1 plants that also displayed very high expression of the symbiotic cbb ₃ oxidase ( fixN d).

  5. CO2 enrichment affects eco-physiological growth of maize and alfalfa under different water stress regimes in the UAE.

    Science.gov (United States)

    Ksiksi, Taoufik Saleh; Ppoyil, Shaijal Babu Thru; Palakkott, Abdul Rasheed

    2018-03-01

    Water stress has been reported to alter morphology and physiology of plants affecting chlorophyll content, stomatal size and density. In this study, drought stress mitigating effects of CO 2 enrichment was assessed in greenhouse conditions in the hot climate of UAE. Commercially purchased maize ( Zea mays L.) and alfalfa ( Medicago sativa L.) were seeded in three different custom-built cage structures, inside a greenhouse. One cage was kept at 1000 ppm CO 2 , the second at 700 ppm CO 2 , and the third at ambient greenhouse CO 2 environment (i.e. 435 ppm). Three water stress treatments HWS (200 ml per week), MWS (400 ml per week), and CWS (600 ml per week) were given to each cage so that five maize pots and five alfalfa pots in each cage received same water stress treatments. In maize, total chlorophyll content was similar or higher in water stress treatments compared to control for all CO 2 concentrations. Stomatal lengths were higher in enriched CO 2 environments under water stress. At 700 ppm CO 2 , stomatal widths decreased as water stress increased from MWS to HWS. At both enriched CO 2 environments, stomatal densities decreased compared to ambient CO 2 environment. In alfalfa, there was no significant increase in total chlorophyll content under enriched CO 2 environments, even though a slight increase was noticed.

  6. Development of lucerne (Medicago sativa L.) treated with mineral fertilizer and manure at optimal and water deficit conditions.

    Science.gov (United States)

    Vasileva, V; Kostov, O; Vasilev, E

    2006-01-01

    A study on the effect of different rates of mineral fertilizer and manure on yield parameters of lucerne under optimal and water deficit conditions was carried out. Leached chernozem soil and lucerne cultivar Victoria were used. The soil was treated with ammonium nitrate and fully matured cattle manure. The plants were grown under optimum moisture content of 80% and 40% of field capacity. The water deficit stress decreased top and root biomass by 11-75% and 3-29% at mineral and organic fertilization, respectively. The applied mineral and organic N strongly depressed nodules development. Both mineral fertilizer and organic manure at dose of 210 mg N kg(-1) soil completely inhibited the appearance of nodules. Next to nitrogen, water deficit stress further inhibited the development of nodules. Nitrogen fertilization increased seed productivity in the two experimental moisture conditions. The water deficit stress decreased seed productivity by 18 to 33% as compared to optimum conditions. The plant treatments with manure were much more resistant to water deficit and recovering ability of plants was faster as compared to treatments with mineral fertilizer. The application of manure stimulates development of drought-stress tolerance in lucerne. However, the results obtained can be considered for the soil type and experimental conditions used.

  7. 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.

  8. 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

  9. Plants in water-controlled ecosystems: active role in hydrologic processes and response to water stress. IV. Discussion of real cases

    Science.gov (United States)

    Laio, F.; Porporato, A.; Fernandez-Illescas, C. P.; Rodriguez-Iturbe, I.

    Three water-controlled ecosystems are studied here using the stochastic description of soil moisture dynamics and vegetation water stress proposed in Part II (F. Laio, A. Porporato, L. Ridolfi, I. Rodriguez-Iturbe, Adv. Water Res. 24 (7) (2001) 707-723) and Part III (A. Porporato, F. Laio, L. Ridolfi, I. Rodriguez-Iturbe, Adv. Water Res. 24 (7) (2001) 725-744) of this series of papers. In the savanna of Nylsvley (South Africa) the very diverse physiological characteristics of the existing plants give rise to different strategies of soil moisture exploitation. Notwithstanding these differences, the vegetation water stress for all the species turns out to be very similar, suggesting that coexistence might be attained also through differentiation of water use. The case of the savanna of Southern Texas points out how rooting depth and interannual rainfall variability can impact soil moisture dynamics and vegetation water stress. Because of the different responses to water stress of trees and grasses, external climatic forcing could be at the origin of the dynamic equilibrium allowing coexistence in this ecosystem. Finally, the analysis of a short grass steppe in Colorado provides an interesting example of the so-called inverse texture effect, whereby preferential conditions for vegetation are dependent on soil texture and rainfall. Sites which are more favorable during wet conditions may become less suitable to the same vegetation type during drier years. Such an effect is important to explain the predominance of existing species, as well as to investigate their reproductive strategies.

  10. 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.

  11. Impacts of water stress, environment and rootstock on the diurnal behaviour of stem water potential and leaf conductance in pistachio (Pistacia vera L.)

    International Nuclear Information System (INIS)

    Memmi, H.; Couceiro, J.F.; Gijón, C.; Pérez-López, D.

    2016-01-01

    Little information is available on the diurnal behaviour of water potential and leaf conductance on pistachio trees despite their relevance to fine tune irrigation strategies. Mature pistachio trees were subject to simultaneous measurements of stem water potential (Ψx) and leaf conductance (gl) during the day, at three important periods of the irrigation season. Trees were grown on three different rootstocks and water regimes. An initial baseline relating Ψx to air vapor pressure deficit (VPD) is presented for irrigation scheduling in pistachio. Ψx was closely correlated with VPD but with a different fit according to the degree of water stress. No evidence of the variation of Ψx in relation to the phenology of the tree was observed. Furthermore, midday Ψx showed more accuracy to indicate a situation of water stress than predawn water potential. Under well irrigated conditions, gl was positively correlated with VPD during stage II of growth reaching its peak when VPD reached its maximum value (around 4 kPa). This behaviour changed during stage III of fruit growth suggesting a reliance of stomatal behaviour to the phenological stage independently to the tree water status. The levels of water stress reached were translated in a slow recovery of tree water status and leaf conductance (more than 40 days). Regarding rootstocks, P. integerrima showed little adaptation to water shortage compared to the two other rootstocks under the studied conditions. (Author)

  12. Impacts of water stress, environment and rootstock on the diurnal behaviour of stem water potential and leaf conductance in pistachio (Pistacia vera L.

    Directory of Open Access Journals (Sweden)

    Houssem Memmi

    2016-06-01

    Full Text Available Little information is available on the diurnal behaviour of water potential and leaf conductance on pistachio trees despite their relevance to fine tune irrigation strategies. Mature pistachio trees were subject to simultaneous measurements of stem water potential (Ψx and leaf conductance (gl during the day, at three important periods of the irrigation season. Trees were grown on three different rootstocks and water regimes. An initial baseline relating Ψx to air vapor pressure deficit (VPD is presented for irrigation scheduling in pistachio. Ψx was closely correlated with VPD but with a different fit according to the degree of water stress. No evidence of the variation of Ψx in relation to the phenology of the tree was observed. Furthermore, midday Ψx showed more accuracy to indicate a situation of water stress than predawn water potential. Under well irrigated conditions, gl was positively correlated with VPD during stage II of growth reaching its peak when VPD reached its maximum value (around 4 kPa. This behaviour changed during stage III of fruit growth suggesting a reliance of stomatal behaviour to the phenological stage independently to the tree water status. The levels of water stress reached were translated in a slow recovery of tree water status and leaf conductance (more than 40 days. Regarding rootstocks, P. integerrima showed little adaptation to water shortage compared to the two other rootstocks under the studied conditions.

  13. Impacts of water stress, environment and rootstock on the diurnal behaviour of stem water potential and leaf conductance in pistachio (Pistacia vera L.)

    Energy Technology Data Exchange (ETDEWEB)

    Memmi, H.; Couceiro, J.F.; Gijón, C.; Pérez-López, D.

    2016-11-01

    Little information is available on the diurnal behaviour of water potential and leaf conductance on pistachio trees despite their relevance to fine tune irrigation strategies. Mature pistachio trees were subject to simultaneous measurements of stem water potential (Ψx) and leaf conductance (gl) during the day, at three important periods of the irrigation season. Trees were grown on three different rootstocks and water regimes. An initial baseline relating Ψx to air vapor pressure deficit (VPD) is presented for irrigation scheduling in pistachio. Ψx was closely correlated with VPD but with a different fit according to the degree of water stress. No evidence of the variation of Ψx in relation to the phenology of the tree was observed. Furthermore, midday Ψx showed more accuracy to indicate a situation of water stress than predawn water potential. Under well irrigated conditions, gl was positively correlated with VPD during stage II of growth reaching its peak when VPD reached its maximum value (around 4 kPa). This behaviour changed during stage III of fruit growth suggesting a reliance of stomatal behaviour to the phenological stage independently to the tree water status. The levels of water stress reached were translated in a slow recovery of tree water status and leaf conductance (more than 40 days). Regarding rootstocks, P. integerrima showed little adaptation to water shortage compared to the two other rootstocks under the studied conditions. (Author)

  14. Improving Estimation of Evapotranspiration under Water-Limited Conditions Based on SEBS and MODIS Data in Arid Regions

    Directory of Open Access Journals (Sweden)

    Chunlin Huang

    2015-12-01

    Full Text Available This study proposes a method for improving the estimation of surface turbulent fluxes in surface energy balance system (SEBS model under water stress conditions using MODIS data. The normalized difference water index (NDWI as an indicator of water stress is integrated into SEBS. To investigate the feasibility of the new approach, the desert-oasis region in the middle reaches of the Heihe River Basin (HRB is selected as the study area. The proposed model is calibrated with meteorological and flux data over 2008–2011 at the Yingke station and is verified with data from 16 stations of the Heihe Watershed Allied Telemetry Experimental Research (HiWATER project in 2012. The results show that soil moisture significantly affects evapotranspiration (ET under water stress conditions in the study area. Adding the NDWI in SEBS can significantly improve the estimations of surface turbulent fluxes in water-limited regions, especially for spare vegetation cover area. The daily ET maps generated by the new model also show improvements in drylands with low ET values. This study demonstrates that integrating the NDWI into SEBS as an indicator of water stress is an effective way to improve the assessment of the regional ET in semi-arid and arid regions.

  15. Cytokinins induce transcriptional reprograming and improve Arabidopsis plant performance under drought and salt stress conditions.

    Directory of Open Access Journals (Sweden)

    Natali Shirron

    2016-10-01

    Full Text Available In nature, annual plants respond to abiotic stresses by activating a specific genetic program leading to early flowering and accelerated senescence. Although, in nature, this phenomenon supports survival under unfavorable environmental conditions, it may have negative agro-economic impacts on crop productivity. Overcoming this genetic programing by cytokinins (CK has recently been shown in transgenic plants that overproduce CK. These transgenic plants displayed a significant increase in plant productivity under drought stress conditions. We investigated the role of CK in reverting the transcriptional program that is activated under abiotic stress conditions and allowing sustainable plant growth. We employed 2 complementary approaches: Ectopic overexpression of CK, and applying exogenous CK to detached Arabidopsis leaves. Transgenic Arabidopsis plants transformed with the isopentyltransferase (IPT gene under the regulation of the senescence associated receptor kinase (SARK promoter displayed a significant drought resistance. A transcriptomic analysis using RNA sequencing was performed to explore the response mechanisms under elevated CK levels during salinity stress. This analysis showed that under such stress, CK triggered transcriptional reprograming that resulted in attenuated stress-dependent inhibition of vegetative growth and delayed premature plant senescence. Our data suggest that elevated CK levels led to stress tolerance by retaining the expression of genes associated with plant growth and metabolism whose expression typically decreases under stress conditions. In conclusion, we hypothesize that CK allows sustainable plant growth under unfavorable environmental conditions by activating gene expression related to growth processes and by preventing the expression of genes related to the activation of premature senescence.

  16. Effect of water deprivation on baseline and stress-induced corticosterone levels in the Children's python (Antaresia childreni).

    Science.gov (United States)

    Dupoué, Andréaz; Angelier, Frédéric; Lourdais, Olivier; Bonnet, Xavier; Brischoux, François

    2014-02-01

    Corticosterone (CORT) secretion is influenced by endogenous factors (e.g., physiological status) and environmental stressors (e.g., ambient temperature). Heretofore, the impact of water deprivation on CORT plasma levels has not been thoroughly investigated. However, both baseline CORT and stress-induced CORT are expected to respond to water deprivation not only because of hydric stress per se, but also because CORT is an important mineralocorticoid in vertebrates. We assessed the effects of water deprivation on baseline CORT and stress-induced CORT, in Children's pythons (Antaresia childreni), a species that experiences seasonal droughts in natural conditions. We imposed a 52-day water deprivation on a group of unfed Children's pythons (i.e., water-deprived treatment) and provided water ad libitum to another group (i.e., control treatment). We examined body mass variations throughout the experiment, and baseline CORT and stress-induced CORT at the end of the treatments. Relative body mass loss averaged ~10% in pythons without water, a value 2 to 4 times higher compared to control snakes. Following re-exposition to water, pythons from the water-deprived treatment drank readily and abundantly and attained a body mass similar to pythons from the control treatment. Together, these results suggest a substantial dehydration as a consequence of water deprivation. Interestingly, stress-induced but not baseline CORT level was significantly higher in water-deprived snakes, suggesting that baseline CORT might not respond to this degree of dehydration. Therefore, possible mineralocorticoid role of CORT needs to be clarified in snakes. Because dehydration usually induces adjustments (reduced movements, lowered body temperature) to limit water loss, and decreases locomotor performances, elevated stress-induced CORT in water-deprived snakes might therefore compensate for altered locomotor performances. Future studies should test this hypothesis. Copyright © 2013 Elsevier Inc

  17. Studies on Screening of Maize (Zea mays L.) Hybrids under Drought Stress Conditions

    OpenAIRE

    Zahoor Ahmad

    2015-01-01

    Drought is one of the most serious problems posing a grave threat to cereals production including maize. Two experiments (lab and wire house) were conducted to screen out the most tolerant and most sensitive maize hybrids (7386, 6525, Hycorn, 9696, 32B33, 3672, MMRI and 31P41) under artificial imposing drought stress by PEG-6000 and under water stress applied after seedling emergence. In first experiment five water stress levels such as zero (control), -0.2 MPa, -0.4 MPa, -0.6 MPa, and -0.8 M...

  18. 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.

  19. Evaluating stress analysis and failure criteria for offshore structures for Pechora Sea conditions

    Science.gov (United States)

    Nesic, S.; Donskoy, Y.; Zolotukhin, A.

    2017-12-01

    Development of Arctic hydrocarbon resources has faced many challenges due to sensitive environmental conditions including low temperatures, ice cover and terrestrial permafrost and extreme seasonal variation in sunlight. Russian offshore field development in Arctic region is usually associated with annual ice cover, which can cause serious damage on the offshore platforms. The Pechora Sea has claimed as one of the most perspective oil and gas region of the Russian Arctic with seven discovered oil and gas fields and several dozens of structures. Our rough assessment, based on in-place hydrocarbon volumes and recovery factor evaluation concept, indicates that Pechora Sea alone has in-place volumes amounting to ca. 20 billion barrel oil equivalent (BOE). This quantity is enough to secure produced volumes by 2040 exceeding 3 billion BOE [1] that indicates huge resource potential of the region. The environmental conditions are primarily function of water dynamics and ice cover. The sea is covered by the ice for greatest part of the year. In this article, the ice load simulations were performed using explicit dynamic analysis system in ANSYS software to determine best shape and size of an offshore platform for the Pechora Sea ice conditions. Different gravity based structures (GBS) were analyzed: artificial island, hollow cylindrical and conical concrete structures and four-leg GBS. Relationships between the stress, deformations and time were analyzed and important observations from the simulation results were a basis for selecting the most preferable structures.

  20. From microgravity to osmotic conditions: mechanical integration of plant cells in response to stress

    Science.gov (United States)

    Wojtaszek, Przemyslaw; Kasprowicz, Anna; Michalak, Michal; Janczara, Renata; Volkmann, Dieter; Baluska, Frantisek

    Chemical reactions and interactions between molecules are commonly thought of as being at the basis of Life. Research of recent years, however, is more and more evidently indicating that physical forces are profoundly affecting the functioning of life at all levels of its organiza-tion. To detect and to respond to such forces, plant cells need to be integrated mechanically. Cell walls are the outermost functional zone of plant cells. They surround the individual cells, and also form a part of the apoplast. In cell suspensions, cell walls are embedded in the cul-ture medium which can be considered as a superapoplast. Through physical and chemical interactions they provide a basis for the structural and functional cell wall-plasma membrane-cytoskeleton (WMC) continuum spanning the whole cell. Here, the working of WMC contin-uum, and the participation of signalling molecules, like NO, would be presented in the context of plant responses to stress. In addition, the effects of the changing composition of WMC continuum will be considered, with particular attention paid to the modifications of the WMC components. Plant cells are normally adapted to changing osmotic conditions, resulting from variable wa-ter availability. The appearance of the osmotic stress activates adaptory mechanisms. If the strength of osmotic stress grows relatively slowly over longer period of time, the cells are able to adapt to conditions that are lethal to non-adapted cells. During stepwise adaptation of tobacco BY-2 suspension cells to the presence of various osmotically active agents, cells diverged into independent, osmoticum type-specific lines. In response to ionic agents (NaCl, KCl), the adhe-sive properties were increased and randomly dividing cells formed clumps, while cells adapted to nonionic osmotica (mannitol, sorbitol, PEG) revealed ordered pattern of precisely positioned cell divisions, resulting in the formation of long cell files. Changes in the growth patterns were accompanied by

  1. Global Transcriptional Responses to Osmotic, Oxidative, and Imipenem Stress Conditions in Pseudomonas putida

    DEFF Research Database (Denmark)

    Bojanovic, Klara; D'Arrigo, Isotta; Long, Katherine

    2017-01-01

    functional roles in the cellular response to stress conditions. The data show a larger fraction of differentially expressed sRNAs than of mRNAs with >5-fold expression changes. The work provides detailed insights into the mechanisms through which P. putida responds to different stress conditions...... intergenic and antisense transcripts, were detected, increasing the number of identified sRNA transcripts in the strain by a factor of 10. Unique responses to each type of stress are documented, including both the extent and dynamics of the gene expression changes. The work adds rich detail to previous......Bacteria cope with and adapt to stress by modulating gene expression in response to specific environmental cues. In this study, the transcriptional response of Pseudomonas putida KT2440 to osmotic, oxidative, and imipenem stress conditions at two time points was investigated via identification...

  2. Influence of stress on fear memory processes in an aversive differential conditioning paradigm in humans.

    Science.gov (United States)

    Bentz, Dorothée; Michael, Tanja; Wilhelm, Frank H; Hartmann, Francina R; Kunz, Sabrina; von Rohr, Isabelle R Rudolf; de Quervain, Dominique J-F

    2013-07-01

    It is widely assumed that learning and memory processes play an important role in the pathogenesis, expression, maintenance and therapy of anxiety disorders, such as phobias or post-traumatic stress disorder (PTSD). Memory retrieval is involved in symptom expression and maintenance of these disorders, while memory extinction is believed to be the underlying mechanism of behavioral exposure therapy of anxiety disorders. There is abundant evidence that stress and stress hormones can reduce memory retrieval of emotional information, whereas they enhance memory consolidation of extinction training. In this study we aimed at investigating if stress affects these memory processes in a fear conditioning paradigm in healthy human subjects. On day 1, fear memory was acquired through a standard differential fear conditioning procedure. On day 2 (24h after fear acquisition), participants either underwent a stressful cold pressor test (CPT) or a control condition, 20 min before memory retrieval testing and extinction training. Possible prolonged effects of the stress manipulation were investigated on day 3 (48 h after fear acquisition), when memory retrieval and extinction were tested again. On day 2, men in the stress group showed a robust cortisol response to stress and showed lower unconditioned stimulus (US) expectancy ratings than men in the control group. This reduction in fear memory retrieval was maintained on day 3. In women, who showed a significantly smaller cortisol response to stress than men, no stress effects on fear memory retrieval were observed. No group differences were observed with respect to extinction. In conclusion, the present study provides evidence that stress can reduce memory retrieval of conditioned fear in men. Our findings may contribute to the understanding of the effects of stress and glucocorticoids on fear symptoms in anxiety disorders and suggest that such effects may be sex-specific. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Combined effect of water loss and wounding stress on gene activation of metabolic pathways associated with phenolic biosynthesis in carrot

    Directory of Open Access Journals (Sweden)

    Alejandro eBecerra-Moreno

    2015-10-01

    Full Text Available Abstract: The application of postharvest abiotic stresses is an effective strategy to activate the primary and secondary metabolism of plants inducing the accumulation of antioxidant phenolic compounds. In the present study, the effect of water stress applied alone and in combination with wounding stress on the activation of primary (shikimic acid and secondary (phenylpropanoid metabolic pathways related with the accumulation of phenolic compound in plants was evaluated. Carrot (Daucus carota was used as model system for this study, and the effect of abiotic stresses was evaluated at the gene expression level and on the accumulation of metabolites. As control of the study, whole carrots were stored under the same conditions. Results demonstrated that water stress activated the primary and secondary metabolism of carrots, favoring the lignification process. Likewise, wounding stress induced higher activation of the primary and secondary metabolism of carrots as compared to water stress alone, leading to higher accumulation of shikimic acid, phenolic compounds and lignin. Additional water stress applied on wounded carrots exerted a synergistic effect on the wound-response at the gene expression level. For instance, when wounded carrots were treated with water stress, the tissue showed 20- and 14-fold increases in the relative expression of 3-deoxy-D-arabino-heptulosanate synthase and phenylalanine ammonia-lyase genes, respectively. However, since lignification was increased, lower accumulation of phenolic compounds was detected. Indicatively, at 48 h of storage, wounded carrots treated with water stress showed ~31% lower levels of phenolic compounds and ~23% higher lignin content as compared with wounded controls. In the present study, it was demonstrated that water stress is one of the pivotal mechanism of the wound-response in carrot. Results allowed the elucidation of strategies to induce the accumulation of specific primary or secondary

  4. Measurement of heat stress conditions at cow level and comparison to climate conditions at stationary locations inside a dairy barn.

    Science.gov (United States)

    Schüller, Laura K; Heuwieser, Wolfgang

    2016-08-01

    The objectives of this study were to examine heat stress conditions at cow level and to investigate the relationship to the climate conditions at 5 different stationary locations inside a dairy barn. In addition, we compared the climate conditions at cow level between primiparous and multiparous cows for a period of 1 week after regrouping. The temperature-humidity index (THI) differed significantly between all stationary loggers. The lowest THI was measured at the window logger in the experimental stall and the highest THI was measured at the central logger in the experimental stall. The THI at the mobile cow loggers was 2·33 THI points higher than at the stationary loggers. Furthermore, the mean daily THI was higher at the mobile cow loggers than at the stationary loggers on all experimental days. The THI in the experimental pen was 0·44 THI points lower when the experimental cow group was located inside the milking parlour. The THI measured at the mobile cow loggers was 1·63 THI points higher when the experimental cow group was located inside the milking parlour. However, there was no significant difference for all climate variables between primiparous and multiparous cows. These results indicate, there is a wide range of climate conditions inside a dairy barn and especially areas with a great distance to a fresh air supply have an increased risk for the occurrence of heat stress conditions. Furthermore, the heat stress conditions are even higher at cow level and cows not only influence their climatic environment, but also generate microclimates within different locations inside the barn. Therefore climate conditions should be obtained at cow level to evaluate the heat stress conditions that dairy cows are actually exposed to.

  5. 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

  6. Effect of experimental stress in 2 different pain conditions affecting the facial muscles.

    Science.gov (United States)

    Woda, Alain; L'heveder, Gildas; Ouchchane, Lemlih; Bodéré, Céline

    2013-05-01

    Chronic facial muscle pain is a common feature in both fibromyalgia (FM) and myofascial (MF) pain conditions. In this controlled study, a possible difference in the mode of deregulation of the physiological response to a stressing stimulus was explored by applying an acute mental stress to FM and MF patients and to controls. The effects of the stress test were observed on pain, sympathetic variables, and both tonic and reflex electromyographic activities of masseteric and temporal muscles. The statistical analyses were performed through a generalized linear model including mixed effects. Painful reaction to the stressor was stronger (P < .001) and longer (P = .011) in FM than in MF independently of a higher pain level at baseline. The stress-induced autonomic changes only seen in FM patients did not reach significance. The electromyographic responses to the stress test were strongest for controls and weakest for FM. The stress test had no effect on reflex activity (area under the curve [AUC]) or latency, although AUC was high in FM and latencies were low in both pain groups. It is suggested that FM is characterized by a lower ability to adapt to acute stress than MF. This study showed that an acute psychosocial stress triggered several changes in 2 pain conditions including an increase in pain of larger amplitude in FM than in MF pain. Similar stress-induced changes should be explored as possible mechanisms for differentiation between dysfunctional pain conditions. Copyright © 2013 American Pain Society. Published by Elsevier Inc. All rights reserved.

  7. Gas exchange and antioxidant activity in seedlings of C opaifera langsdorffii Desf. under different water conditions.

    Science.gov (United States)

    Rosa, Derek B C J; Scalon, Silvana P Q; Cremon, Thais; Ceccon, Felipe; Dresch, Daiane M

    2017-01-01

    The aim of this study was to evaluate gas exchange, efficiency of the photosynthetic apparatus, and antioxidant activity in Copaifera langsdorffii Desf. The seedlings were cultivated under different conditions of water availability, in order to improve the utilization efficiency of available water resources. The seedlings were cultivated in four different water retention capacities (WRC- 25%, 50%, 75%, and 100%), and evaluated at four different time (T- 30, 60, 90, and 120 days). During the experimental period, seedlings presented the highest values for carboxylation efficiency of Rubisco (A/Ci), intrinsic water use efficiency (IWUE = A/gs), chlorophyll index, and stomatal opening, when grown in the substrate with 75% WRC, but the stomatal index (SI) was less the 25% WRC. The efficiency of photosystem II was not significantly altered by the treatments. Comparison between the extreme treatments in terms of water availability, represented by 25% and 100% WRC, represent stress conditions for the species. Water availability causes a high activity of antioxidant enzymes (superoxide dismutase, peroxidase, and catalase) in the plant.

  8. Gas exchange and antioxidant activity in seedlings of C opaifera langsdorffii Desf. under different water conditions

    Directory of Open Access Journals (Sweden)

    DEREK B.C.J. ROSA

    Full Text Available ABSTRACT The aim of this study was to evaluate gas exchange, efficiency of the photosynthetic apparatus, and antioxidant activity in Copaifera langsdorffii Desf. The seedlings were cultivated under different conditions of water availability, in order to improve the utilization efficiency of available water resources. The seedlings were cultivated in four different water retention capacities (WRC- 25%, 50%, 75%, and 100%, and evaluated at four different time (T- 30, 60, 90, and 120 days. During the experimental period, seedlings presented the highest values for carboxylation efficiency of Rubisco (A/Ci, intrinsic water use efficiency (IWUE = A/gs, chlorophyll index, and stomatal opening, when grown in the substrate with 75% WRC, but the stomatal index (SI was less the 25% WRC. The efficiency of photosystem II was not significantly altered by the treatments. Comparison between the extreme treatments in terms of water availability, represented by 25% and 100% WRC, represent stress conditions for the species. Water availability causes a high activity of antioxidant enzymes (superoxide dismutase, peroxidase, and catalase in the plant.

  9. 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.

  10. Abiotic stress growth conditions induce different responses in kernel iron concentration across genotypically distinct maize inbred varieties

    Science.gov (United States)

    Kandianis, Catherine B.; Michenfelder, Abigail S.; Simmons, Susan J.; Grusak, Michael A.; Stapleton, Ann E.

    2013-01-01

    The improvement of grain nutrient profiles for essential minerals and vitamins through breeding strategies is a target important for agricultural regions where nutrient poor crops like maize contribute a large proportion of the daily caloric intake. Kernel iron concentration in maize exhibits a broad range. However, the magnitude of genotype by environment (GxE) effects on this trait reduces the efficacy and predictability of selection programs, particularly when challenged with abiotic stress such as water and nitrogen limitations. Selection has also been limited by an inverse correlation between kernel iron concentration and the yield component of kernel size in target environments. Using 25 maize inbred lines for which extensive genome sequence data is publicly available, we evaluated the response of kernel iron density and kernel mass to water and nitrogen limitation in a managed field stress experiment using a factorial design. To further understand GxE interactions we used partition analysis to characterize response of kernel iron and weight to abiotic stressors among all genotypes, and observed two patterns: one characterized by higher kernel iron concentrations in control over stress conditions, and another with higher kernel iron concentration under drought and combined stress conditions. Breeding efforts for this nutritional trait could exploit these complementary responses through combinations of favorable allelic variation from these already well-characterized genetic stocks. PMID:24363659

  11. 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.

  12. 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...

  13. Effects of environmental stress on forest crown condition in Europe. Part IV statistical analysis of relationships

    NARCIS (Netherlands)

    Klap, J.M.; Oude Voshaar, J.H.; Vries, de W.; Erisman, J.W.

    2000-01-01

    Site-specific estimates for various environmental stress factors were related with measured crown condition data at a systematic 16 x: 16 km(2) grid over Europe, according to previously stated hypotheses, using a multiple regression approach, including interactions, and lagged effects of stress

  14. Infrared thermometry: a remote sensing technique for predicting yield in water-stressed cotton

    International Nuclear Information System (INIS)

    Pinter, P.J.; Fry, K.E.; Guinn, G.; Mauney, J.R.

    1983-01-01

    A crop water stress index (CWSI) was derived from air temperatures, air vapor pressure deficits and the midday radiant leaf temperatures of cotton plants that were exposed to different early-season irrigation treatments at Phoenix, AZ, U.S.A. To calculate the CWSI, an infrared thermometer was used to measure leaf temperatures which were then scaled relative to minimum and maximum temperatures expected for no-stress (CWSI=0) and extreme drought-stress conditions (CWSI=1). Results showed the CWSI behaved as expected, dropping to low levels following an irrigation and increasing gradually as the cotton plants depleted soil moisture reserves. The final yield of seed cotton was significantly inversely correlated with the average CWSI observed over the interval from the appearance of the first square until two weeks following the final irrigation

  15. Assessment of (Fouquieria splendens ssp. breviflora Cell Cultures Response Under to Water Stress

    Directory of Open Access Journals (Sweden)

    Leonor Angélica Guerrero Zúñiga

    2017-05-01

    Full Text Available Plant cell cultures are homogenous experimental systems, highly controllable that allow the study of short and large water stress adaptations without the interference of the different tissues and development of plants. An approach to understand these adaptations is through the presence of induced proteins; as a result of changes in genetic expression. This work analyze the response of Fouquieria splendens ssp. breviflora cell cultures exposed to abscisic acid (ABA, through the electrophoretic characterization of quantity and quality of stress induced proteins. There were recorded low molecular weight polypeptides (< 35kDa, common in experiments under ABA 10mM, followed by the association with 20 and 30mM ABA conditions, with a particularly response of cell cultures without the stress agent.

  16. Microbial Condition of Water Samples from Foreign Fuel Storage Facilities

    International Nuclear Information System (INIS)

    Berry, C.J.

    1998-01-01

    In order to assess the microbial condition of foreign spent nuclear fuel storage facilities and their possible impact on SRS storage basins, twenty-three water samples were analyzed from 12 different countries. Fifteen of the water samples were analyzed and described in an earlier report (WSRC-TR-97-00365 [1]). This report describes nine additional samples received from October 1997 through March 1998. The samples include three from Australia, two from Denmark and Germany and one sample from Italy and Greece. Each water sample was analyzed for microbial content and activity as determined by total bacteria, viable aerobic bacteria, viable anaerobic bacteria, viable sulfate-reducing bacteria, viable acid-producing bacteria and enzyme diversity. The results for each water sample were then compared to all other foreign samples analyzed to date and monthly samples pulled from the receiving basin for off-site fuel (RBOF), at SRS. Of the nine samples analyzed, four samples from Italy, Germany and Greece had considerably higher microbiological activity than that historically found in the RBOF. This microbial activity included high levels of enzyme diversity and the presence of viable organisms that have been associated with microbial influenced corrosion in other environments. The three samples from Australia had microbial activities similar to that in the RBOF while the two samples from Denmark had lower levels of microbial activity. These results suggest that a significant number of the foreign storage facilities have water quality standards that allow microbial proliferation and survival

  17. Hydrologic conditions in New Hampshire and Vermont, water year 2011

    Science.gov (United States)

    Kiah, Richard G.; Jarvis, Jason D.; Hegemann, Robert F.; Hilgendorf, Gregory S.; Ward, Sanborn L.

    2013-01-01

    Record-high hydrologic conditions in New Hampshire and Vermont occurred during water year 2011, according to data from 125 streamgages and lake gaging stations, 27 creststage gages, and 41 groundwater wells. Annual runoff for the 2011 water year was the sixth highest on record for New Hampshire and the highest on record for Vermont on the basis of a 111-year reference period (water years 1901–2011). Groundwater levels for the 2011 water year were generally normal in New Hampshire and normal to above normal in Vermont. Record flooding occurred in April, May, and August of water year 2011. Peak-of-record streamflows were recorded at 38 streamgages, 25 of which had more than 10 years of record. Flooding in April 2011 was widespread in parts of northern New Hampshire and Vermont; peak-of-record streamflows were recorded at nine streamgages. Flash flooding in May 2011 was isolated to central and northeastern Vermont; peakof- record streamflows were recorded at five streamgages. Devastating flooding in August 2011 occurred throughout most of Vermont and in parts of New Hampshire as a result of the heavy rains associated with Tropical Storm Irene. Peak-ofrecord streamflows were recorded at 24 streamgages.

  18. Tremor frequency characteristics in Parkinson's disease under resting-state and stress-state conditions.

    Science.gov (United States)

    Lee, Hong Ji; Lee, Woong Woo; Kim, Sang Kyong; Park, Hyeyoung; Jeon, Hyo Seon; Kim, Han Byul; Jeon, Beom S; Park, Kwang Suk

    2016-03-15

    Tremor characteristics-amplitude and frequency components-are primary quantitative clinical factors for diagnosis and monitoring of tremors. Few studies have investigated how different patient's conditions affect tremor frequency characteristics in Parkinson's disease (PD). Here, we analyzed tremor characteristics under resting-state and stress-state conditions. Tremor was recorded using an accelerometer on the finger, under resting-state and stress-state (calculation task) conditions, during rest tremor and postural tremor. The changes of peak power, peak frequency, mean frequency, and distribution of power spectral density (PSD) of tremor were evaluated across conditions. Patients whose tremors were considered more than "mild" were selected, for both rest (n=67) and postural (n=25) tremor. Stress resulted in both greater peak powers and higher peak frequencies for rest tremor (pstate condition. The distributions of PSD of tremor were symmetrical, regardless of conditions. Tremor is more evident and typical tremor characteristics, namely a lower frequency as amplitude increases, are different in stressful condition. Patient's conditions directly affect neural oscillations related to tremor frequencies. Therefore, tremor characteristics in PD should be systematically standardized across patient's conditions such as attention and stress levels. Copyright © 2016. Published by Elsevier B.V.

  19. Possibilities of crack mouth opening displacement (CMOD) measurement under boiling and pressurized water reactor conditions

    International Nuclear Information System (INIS)

    Ehling, W.

    1984-01-01

    Fracture mechanics investigations carried out so far in laboratory conditions cover only part of the material stresses, as effects which occur in nuclear powerstations, in particular, such as corrosion and radioactive radiation are largely left out of account. Therefore experiments including these effects were recently carried out in autoclaves, test rigs simulating reactors (HRD experimental plant) and in experimental reactors. An important parameter of experimental fracture mechanics is the measurement of crack opening displacement (COD). The crack opening is measured with socalled clip gauges (transmitters based on strain gauges, which convert mechanical deformation of springs into electrical signals) on standard samples in the laboratory. It was therefore sensible to use these high temperature strain gauges (HTD) for the development of a measuring system for travel for pressurized water and boiling water reactor conditions. (orig.) [de

  20. Structural Modifications of Fructans in Aloe barbadensis Miller (Aloe Vera) Grown under Water Stress.

    Science.gov (United States)

    Salinas, Carlos; Handford, Michael; Pauly, Markus; Dupree, Paul; Cardemil, Liliana

    2016-01-01

    Aloe barbadensis Miller (Aloe vera) has a Crassulaceae acid metabolism which grants the plant great tolerance to water restrictions. Carbohydrates such as acemannans and fructans are among the molecules responsible for tolerating water deficit in other plant species. Nevertheless, fructans, which are prebiotic compounds, have not been described nor studied in Aloe vera, whose leaf gel is known to possess beneficial pharmaceutical, nutritional and cosmetic properties. As Aloe vera is frequently cultivated in semi-arid conditions, like those found in northern Chile, we investigated the effect of water deficit on fructan composition and structure. For this, plants were subjected to different irrigation regimes of 100%, 75%, 50% and 25% field capacity (FC). There was a significant increase in the total sugars, soluble sugars and oligo and polyfructans in plants subjected to water deficit, compared to the control condition (100% FC) in both leaf tips and bases. The amounts of fructans were also greater in the bases compared to the leaf tips in all water treatments. Fructans also increase in degree of polymerization with increasing water deficit. Glycosidic linkage analyses by GC-MS, led to the conclusion that there are structural differences between the fructans present in the leaves of control plants with respect to plants irrigated with 50% and 25% FC. Therefore, in non-stressed plants, the inulin, neo-inulin and neo-levan type of fructans predominate, while in the most stressful conditions for the plant, Aloe vera also synthesizes fructans with a more branched structure, the neofructans. To our knowledge, the synthesis and the protective role of neo-fructans under extreme water deficit has not been previously reported.

  1. Compositions and methods for providing plants with tolerance to abiotic stress conditions

    KAUST Repository

    Hirt, Heribert; De Zelicourt, Axel; Saad, Maged

    2017-01-01

    It has been discovered that the desert endophytic bacterium SA187 SA187 can provide resistance or tolerance to abiotic stress conditions to seeds or plants. Compositions containing SA187 can be used to enhance plant development and yield under

  2. Poly(3-hydroxybutyrate) production in an integrated electromicrobial setup: Investigation under stress-inducing conditions

    KAUST Repository

    Al Rowaihi, Israa Salem; Paillier, Alexis; Rasul, Shahid; Karan, Ram; Grö tzinger, Stefan Wolfgang; Takanabe, Kazuhiro; Eppinger, Jö rg

    2018-01-01

    extorquens AM1 and Cupriavidus necator H16. This setup allows to investigate the influence of different stress conditions, such as coexisting electrolysis, relatively high salinity, nutrient limitation, and starvation, on the production of PHB. The overall

  3. Gas Exchanges and Stem Water Potential Define Stress Thresholds for Efficient Irrigation Management in Olive (Olea europea L.

    Directory of Open Access Journals (Sweden)

    Giulia Marino

    2018-03-01

    Full Text Available With climate change and decreased water supplies, interest in irrigation scheduling based on plant water status is increasing. Stem water potential (ΨSWP thresholds for irrigation scheduling in olive have been proposed, however, a physiologically-based evaluation of their reliability is needed. A large dataset collected at variable environmental conditions, growing systems, and genotypes was used to characterize the relation between ΨSWP and gas exchanges for olive. Based on the effect of drought stress on the ecophysiological parameters monitored, we described three levels of stress: no stress (ΨSWP above about −2 MPa, where the high variability of stomatal conductance (gs suggests a tight stomatal control of water loss that limit ΨSWP drop, irrigation volumes applied to overcome this threshold had no effect on assimilation but reduced intrinsic water use efficiency (iWUE; moderate-stress (ΨSWP between about −2.0 and −3.5 MPa, where iWUE can be increased without damage to the photosynthetic apparatus of leaves; and high-stress (ΨSWP below about −3.5 MPa, where gs dropped below 150 mmol m−2 s−1 and the intercellular CO2 concentration increased proportionally, suggesting non-stomatal limitation to photosynthesis was operative. This study confirmed that olive ΨSWP should be maintained between −2 and −3.5 MPa for optimal irrigation efficiency and to avoid harmful water stress levels.

  4. Hand immersion in cold water alleviating physiological strain and increasing tolerance to uncompensable heat stress.

    Science.gov (United States)

    Khomenok, Gennadi A; Hadid, Amir; Preiss-Bloom, Orahn; Yanovich, Ran; Erlich, Tomer; Ron-Tal, Osnat; Peled, Amir; Epstein, Yoram; Moran, Daniel S

    2008-09-01

    The current study examines the use of hand immersion in cold water to alleviate physiological strain caused by exercising in a hot climate while wearing NBC protective garments. Seventeen heat acclimated subjects wearing a semi-permeable NBC protective garment and a light bulletproof vest were exposed to a 125 min exercise-heat stress (35 degrees C, 50% RH; 5 km/h, 5% incline). The heat stress exposure routine included 5 min rest in the chamber followed by two 50:10 min work-rest cycles. During the control trial (CO), there was no intervention, whilst in the intervention condition the subjects immersed their hands and forearms in a 10 degrees C water bath (HI). The results demonstrated that hand immersion in cold water significantly reduced physiological strain. In the CO exposure during the first and second resting periods, the average rectal temperature (T (re)) practically did not decrease. With hand immersion, the mean (SD) T (re) decreased by 0.45 (0.05 degrees C) and 0.48 degrees C (0.06 degrees C) during the first and second rest periods respectively (P immersion in cold water for 10 min is an effective method for decreasing the physiological strain caused by exercising under heat stress while wearing NBC protective garments. The method is convenient, simple, and allows longer working periods in hot or contaminated areas with shorter resting periods.

  5. Growth, photosynthesis and antioxidant responses of endophyte infected and non-infected rice under lead stress conditions.

    Science.gov (United States)

    Li, Xuemei; Bu, Ning; Li, Yueying; Ma, Lianju; Xin, Shigang; Zhang, Lihong

    2012-04-30

    An endophytic fungus was tested in rice (Oryza sativa L.) exposed to four levels of lead (Pb) stress (0, 50, 100 and 200 μM) to assess effects on plant growth, photosynthesis and antioxidant enzyme activity. Under Pb stress conditions, endophyte-infected seedlings had greater shoot length but lower root length compared to non-infected controls, and endophyte-infected seedlings had greater dry weight in the 50 and 100 μM Pb treatments. Under Pb stress conditions, chlorophyll and carotenoid levels were significantly higher in the endophyte-infected seedlings. Net photosynthetic rate, transpiration rate and water use efficiency were significantly higher in endophyte-infected seedlings in the 50 and 100 μM Pb treatments. In addition, chlorophyll fluorescence parameters Fv/Fm and Fv/Fo were higher in the infected seedlings compared to the non-infected seedlings under Pb stress. Malondialdehyde accumulation was induced by Pb stress, and it was present in higher concentration in non-infected seedlings under higher concentrations of Pb (100 and 200 μM). Antioxidant activity was either higher or unchanged in the infected seedlings due to responses to the different Pb concentrations. These results suggest that the endophytic fungus improved rice growth under moderate Pb levels by enhancing photosynthesis and antioxidant activity relative to non-infected rice. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. The influence of acute stress on the regulation of conditioned fear

    Directory of Open Access Journals (Sweden)

    Candace M. Raio

    2015-01-01

    Full Text Available Fear learning and regulation is a prominent model for describing the pathogenesis of anxiety disorders and stress-related psychopathology. Fear expression can be modulated using a number of regulatory strategies, including extinction, cognitive emotion regulation, avoidance strategies and reconsolidation. In this review, we examine research investigating the effects of acute stress and stress hormones on these regulatory techniques. We focus on what is known about the impact of stress on the ability to flexibly regulate fear responses that are acquired through Pavlovian fear conditioning. Our primary aim is to explore the impact of stress on fear regulation in humans. Given this, we focus on techniques where stress has been linked to alterations of fear regulation in humans (extinction and emotion regulation, and briefly discuss other techniques (avoidance and reconsolidation where the impact of stress or stress hormones have been mainly explored in animal models. These investigations reveal that acute stress may impair the persistent inhibition of fear, presumably by altering prefrontal cortex function. Characterizing the effects of stress on fear regulation is critical for understanding the boundaries within which existing regulation strategies are viable in everyday life and can better inform treatment options for those who suffer from anxiety and stress-related psychopathology.

  7. Stress analyses of ITER toroidal field coils under fault conditions

    International Nuclear Information System (INIS)

    Jong, C.T.J.

    1990-02-01

    The International Thermonuclear Experimental Reactor (ITER) is intended as an experimental thermonuclear tokamak reactor for testing the basic physics, performance and technologies essential to future fusion reactors. The ITER design will be based on extensive new design work, supported by new physical and technological results, and on the great body of experience built up over several years from previous national and international reactor studies. Conversely, the ITER design process should provide the fusion community with valuable insights into what key areas need further development or clarification as we move forward towards practical fusion power. As part of the design process of the ITER toroidal field coils the mechanical behaviour of the magnetic system under fault conditions has to be analysed in more detail. This paper describes the work carried out to create a detailed finite element model of two toroidal field coils as well as some results of linear elastic analyses with fault conditions. The analyses have been performed with the finite element code ANSYS. (author). 5 refs.; 8 figs.; 2 tabs

  8. Can the responses of photosynthesis and stomatal conductance to water and nitrogen stress combinations be modeled using a single set of parameters?

    NARCIS (Netherlands)

    Zhang, Ningyi; Li, Gang; Yu, Shanxiang; An, Dongsheng; Sun, Qian; Luo, Weihong; Yin, Xinyou

    2017-01-01

    Accurately predicting photosynthesis in response to water and nitrogen stress is the first step toward predicting crop growth, yield and many quality traits under fluctuating environmental conditions. While mechanistic models are capable of predicting photosynthesis under fluctuating environmental

  9. Evaluation of some advanced wheat lines (F7 in normal and drought stress conditions

    Directory of Open Access Journals (Sweden)

    R. Nikseresht

    2016-05-01

    Full Text Available For assessment of drought stress effects on agro characteristics of 30 lines and 6 wheat cultivars and for introducing of drought tolerant and susceptible ones one trial were established using split plot base of randomized complete block design with two replications, main plots were stress and non-stress condition and sub plots contain 30 lines and six wheat cultivars in the check trial, irrigation the farm was done with the normal regime, but in stress trial for germination of seeds and one irrigation in Isfand to the end of rooting the farm was irrigated. Within and end of growth season we measured some agronomic and morphological characters such as yield and its component, height, peduncle length, and etc. Responses of cultivars under stress and non-stress conditions were' different, for example drought stress reduced yield. In spite of this general yield reducing, we found some line, such as 2, 29, 23 had relatively high yield (in tree levels. In order to final evaluate using Factor Analysis, Principal Component, Cluster Analysis .Factor Analysis indicated that four important factors accounted for about 80.245 and 79.624 percent of the total variation among traits in normal and drought stress conditions. With cluster analysis of 36 lines and cultivar using Ward procedure based on Euclidean distance were grouped in 4 distance cluster.

  10. Environmental Growing Conditions in Five Production Systems Induce Stress Response and Affect Chemical Composition of Cocoa (Theobroma cacao L.) Beans.

    Science.gov (United States)

    Niether, Wiebke; Smit, Inga; Armengot, Laura; Schneider, Monika; Gerold, Gerhard; Pawelzik, Elke

    2017-11-29

    Cocoa beans are produced all across the humid tropics under different environmental conditions provided by the region but also by the season and the type of production system. Agroforestry systems compared to monocultures buffer climate extremes and therefore provide a less stressful environment for the understory cocoa, especially under seasonally varying conditions. We measured the element concentration as well as abiotic stress indicators (polyamines and total phenolic content) in beans derived from five different production systems comparing monocultures and agroforestry systems and from two harvesting seasons. Concentrations of N, Mg, S, Fe, Mn, Na, and Zn were higher in beans produced in agroforestry systems with high stem density and leaf area index. In the dry season, the N, Fe, and Cu concentration of the beans increased. The total phenolic content increased with proceeding of the dry season while other abiotic stress indicators like spermine decreased, implying an effect of the water availability on the chemical composition of the beans. Agroforestry systems did not buffer the variability of stress indicators over the seasons compared to monocultures. The effect of environmental growing conditions on bean chemical composition was not strong but can contribute to variations in cocoa bean quality.

  11. Influence of stress conditions on irradiated wheat cultivar (triticum aestivum L.). Vol. 4

    International Nuclear Information System (INIS)

    Salam, T.Z.

    1996-01-01

    This study was carried out from 1992-1994. It aimed to study genetic improvement in yield components namely: shoot length, shoot dry weight, and leaf area at 4, 8, and 12 weeks age under salt stress condition; plant, dry weight/plant earliness, grain yield/plant, and 100 - grain weight at harvest time under drought stress in three mutagenic generations. Results of the two experiments showed that the most suitable mutagenic dose was 75 Gy gamma ray, which caused improvement in stress tolerance for SK 6 9 wheat cultivar by increased growth behaviour, and/or maintaining an active metabolism in plants under salinity and drought conditions. 3 tabs

  12. The influence of water stress on plant hydraulics, gas exchange, berry composition and quality of Pinot Noir wines in Switzerland

    Directory of Open Access Journals (Sweden)

    Vivian Zufferey

    2017-04-01

    Full Text Available Aims : The aims of this study were to investigate the physiological behavior (plant hydraulics, gas exchange of the cultivar Pinot Noir in the field under progressively increasing conditions of water stress and analyze the effects of drought on grape and wine quality. Methods and results : Grapevines of the variety Vitis vinifera L. cv. Pinot Noir (clone 9-18, grafted onto 5BB were subjected to different water regimes (irrigation treatments over the growing season. Physiological indicators were used to monitor plant water status (leaf and stem water potentials and relative carbon isotope composition (d13C in must sugars. Leaf gas exchange (net photosynthesis A and transpiration E, leaf stomatal conductance (gs, specific hydraulic conductivity in petioles (Kpetiole, yield components, berry composition at harvest, and organoleptic quality of wines were analyzed over a 7-year period, between 2009 and 2015, under relatively dry conditions in the canton of Wallis, Switzerland. A progressively increasing water deficit, observed throughout the season, reduced the leaf gas exchange (A and E and gs in non-irrigated vines. The intrinsic water use efficiency (WUEi, A/gs increased during the growing season and was greater in water-stressed vines than in well-watered vines (irrigated vines. This rise in WUEi was correlated with an increase in d13C in must sugars at harvest. Drought led to decreases in Kpetiole, E and sap flow in stems. A decrease in vine plant vigor was observed in vines that had been subjected to water deficits year after year. Moderate water stress during ripening favored sugar accumulation in berries and caused a reduction in total acidic and malic contents in must and available nitrogen content (YAN. Wines produced from water-stressed vines had a deeper color and were richer in anthocyanins and phenol compounds compared with wines from well-watered vines with no water stress. The vine water status greatly influenced the organoleptic

  13. Hippocampal structural plasticity accompanies the resulting contextual fear memory following stress and fear conditioning.

    Science.gov (United States)

    Giachero, Marcelo; Calfa, Gaston D; Molina, Victor A

    2013-10-15

    The present research investigated the resulting contextual fear memory and structural plasticity changes in the dorsal hippocampus (DH) following stress and fear conditioning. This combination enhanced fear retention and increased the number of total and mature dendritic spines in DH. Intra-basolateral amygdala (BLA) infusion of midazolam prior to stress prevented both the enhancement of fear retention and an increase in the density of total and mature dendritic spines in DH. These findings emphasize the role of the stress-induced attenuation of GABAergic neurotransmission in BLA in the promoting influence of stress on fear memory and on synaptic remodeling in DH. In conclusion, the structural remodeling in DH accompanied the facilitated fear memory following a combination of fear conditioning and stressful stimulation.

  14. A study on residual stress mitigation of the HDPE pipe for various annealing conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Sung [Sunchon National University, Sunchon (Korea, Republic of); Yoo, Jeong Ho [Korea Laboratory Engineering System, Daejeon (Korea, Republic of); Oh, Young Jin [KEPCO E and C, Sungnam (Korea, Republic of)

    2015-03-15

    This paper presents effects of the annealing condition variables such as temperature and time on the residual stress mitigation. The effects were investigated by using the various measurement methods such as hole-drilling method and slitting method. As a result of the investigation, the residual stress mitigation magnitude increases with increasing the annealing time and temperature. Based on the investigation results, the quantitative correlations between the annealing variables and the residual stress mitigation were derived. Finally, the effect of long-term operation under the normal operating temperature conditions on the residual stress mitigation was investigated by referring to the derived equations and performing some additional tests, and it is identified that the residual stresses are not significantly relaxed over the design lifetime of the safety class III buried HDPE pipes.

  15. A Non-parametric Method for Calculating Conditional Stressed Value at Risk

    Directory of Open Access Journals (Sweden)

    Kohei Marumo

    2017-01-01

    Full Text Available We consider the Value at Risk (VaR of a portfolio under stressed conditions. In practice, the stressed VaR (sVaR is commonly calculated using the data set that includes the stressed period. It tells us how much the risk amount increases if we use the stressed data set. In this paper, we consider the VaR under stress scenarios. Technically, this can be done by deriving the distribution of profit or loss conditioned on the value of risk factors. We use two methods; the one that uses the linear model and the one that uses the Hermite expansion discussed by Marumo and Wolff (2013, 2016. Numerical examples shows that the method using the Hermite expansion is capable of capturing the non-linear effects such as correlation collapse and volatility clustering, which are often observed in the markets.

  16. Microbiological composition of untreated water during different weather conditions

    Directory of Open Access Journals (Sweden)

    Adna Bešić

    2011-09-01

    Full Text Available Introduction: Water can support the growth of different microorganisms which may result in contamination. Therefore, the microbiological examination is required for testing the hygienic probity of water. In the study of microbial composition of untreated, natural spring and mineral water differences in the presence and number of bacteria during the two periods, winter and summer, are detectable.Methods: In our study, we analyzed and compared the following parameters, specified in the Rulebook: total bacteria and total aerobic bacteria (ml/22 and 37°C, total Coliform bacteria and Coliforms of fecalorigin (MPN/100ml, fecal streptococci as Streptococcus faecalis  (MPN/100ml, Proteus spp (MPN/100ml, and Pseudomonas aeruginosa (MPN/100 ml Sulphoreducing Clostridia (cfu / ml. The paper is a retrospective study in which we processed data related to the period of 2005-2009 year. While working, we used the descriptive-analytical comparative statistical treatment.Results: The obtained results show statistically significant differences in the microbial composition of untreated water in the two observed periods,Conclusions: Findings were consequence of different weather conditions in these periods, which imply a number of other variable factors.

  17. Ecophysiological modeling of grapevine water stress in Burgundy terroirs by a machine-learning approach

    Directory of Open Access Journals (Sweden)

    Luca eBrillante

    2016-06-01

    Full Text Available In a climate change scenario, successful modeling of the relationships between plant-soil-meteorology is crucial for a sustainable agricultural production, especially for perennial crops. Grapevines (Vitis vinifera L. cv Chardonnay located in eight experimental plots (Burgundy, France along a hillslope were monitored weekly for three years for leaf water potentials, both at predawn (Ψpd and at midday (Ψstem. The water stress experienced by grapevine was modeled as a function of meteorological data (minimum and maximum temperature, rainfall and soil characteristics (soil texture, gravel content, slope by a gradient boosting machine. Model performance was assessed by comparison with carbon isotope discrimination (δ13C of grape sugars at harvest and by the use of a test-set. The developed models reached outstanding prediction performance (RMSE < 0.08 MPa for Ψstem and < 0.06 MPa for Ψpd, comparable to measurement accuracy. Model predictions at a daily time step improved correlation with δ13C data, respect to the observed trend at a weekly time scale. The role of each predictor in these models was described in order to understand how temperature, rainfall, soil texture, gravel content and slope affect the grapevine water status in the studied context. This work proposes a straight-forward strategy to simulate plant water stress in field condition, at a local scale; to investigate ecological relationships in the vineyard and adapt cultural practices to future conditions.

  18. Ecophysiological Modeling of Grapevine Water Stress in Burgundy Terroirs by a Machine-Learning Approach.

    Science.gov (United States)

    Brillante, Luca; Mathieu, Olivier; Lévêque, Jean; Bois, Benjamin

    2016-01-01

    In a climate change scenario, successful modeling of the relationships between plant-soil-meteorology is crucial for a sustainable agricultural production, especially for perennial crops. Grapevines (Vitis vinifera L. cv Chardonnay) located in eight experimental plots (Burgundy, France) along a hillslope were monitored weekly for 3 years for leaf water potentials, both at predawn (Ψpd) and at midday (Ψstem). The water stress experienced by grapevine was modeled as a function of meteorological data (minimum and maximum temperature, rainfall) and soil characteristics (soil texture, gravel content, slope) by a gradient boosting machine. Model performance was assessed by comparison with carbon isotope discrimination (δ(13)C) of grape sugars at harvest and by the use of a test-set. The developed models reached outstanding prediction performance (RMSE < 0.08 MPa for Ψstem and < 0.06 MPa for Ψpd), comparable to measurement accuracy. Model predictions at a daily time step improved correlation with δ(13)C data, respect to the observed trend at a weekly time scale. The role of each predictor in these models was described in order to understand how temperature, rainfall, soil texture, gravel content and slope affect the grapevine water status in the studied context. This work proposes a straight-forward strategy to simulate plant water stress in field condition, at a local scale; to investigate ecological relationships in the vineyard and adapt cultural practices to future conditions.

  19. Condition, use, and management of water resources among ...

    African Journals Online (AJOL)

    The study found that water supply in Harshin district is 100% surface water ... Besides, 76% of the respondents were not satisfied with the quality of drinking water. ... Key words: Water resources, pastoralists, rainwater, water-harvesting, gender ...

  20. 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.

  1. 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...

  2. [Corrective effect of aromatherapy on indices of heart rate variability in students under exam stress conditions].

    Science.gov (United States)

    Abrahamyan, H T; Minasyan, S M

    2016-01-01

    There were investigated changes in indices of the activity of regulatory mechanisms of heart rhythm in student under exam stress conditions and the possibility of their correction with aid of aromatherapy. The examination stress was established to be accompanied by pronounced shifts of integral and spectral indices of heart rhythm in students, indicating to the activation of the sympathetic circuit of Autonomic Nervous System in conditions of examination stress. A positive, relaxation impact of the essential oil of orange on the investigated indices was also recorded. The latter is expressed by weakly pronounced changes or lack of them in data of integral and spectral heart rate indices in students from the experimental group, that indicates to the stabilizing effect of used ethereal oil on the psycho-physiological state of students in conditions of exam stress

  3. Effect of infiltrated water on rheology of plagioclase feldspar under lower crustal condition

    Science.gov (United States)

    Kido, M.; Muto, J.; Koizumi, S.; Nagahama, H.

    2016-12-01

    Fluids in the deep crust have an important role in deformation of lithosphere and seismicity. In this study, we performed deformation experiments to reveal rheological properties of plagioclase feldspars as a main constituent of crustal materials with infilitrated water. Axial compression tests on synthetic polycrystalline anorthite (An) were performed in a Griggs-type deformation apparatus at temparature of 900 °C, strain rates of roughly about 10-5 s-1 and various confining pressures of 0.8-1.4 GPa. Distilled water was added on samples before tests. Times for infiltration of water into samples were changed to investigate the variation of strength associated with diffusion of water. Strengths of wet An tended to decrease with infiltration time or strain magnitude. If other conditions such as temperature, time and strain being the same, strengths increase with confining pressures. Recovered samples show that deformation was concentrated in the lower part of samples. Differential stresses were significantly lower than predicted values by a previous flow law for wet An obtained by low pressure gas apparatus ( 0.4 GPa, Rybacki et al., 2006). This implies that the effect of water on mechanical behavior in higher pressure might be larger than those predicted by lower pressure experiments. Ideal water concentration and strength profile of internal of samples were estimated by one-dimensional model of grain boundary diffusion. Estimated strength of internal part of samples was significant higher than measured stresses. There is possibility that cataclastic flow partially occurred in samples. In addition, deformation-enhanced fluid flow probably occurred. In conclusion, strength of wet An depends on water infiltration time, strain magnitude and confining pressure. The results suggest that the strength of fluid-rich regions in the lower crust becomes lower than that predicted by previous studies.

  4. Evaluation Physiological Characteristics and Grain Yield Canola Cultivars under end Seasonal Drought Stress in Weather Condition of Ahvaz

    Directory of Open Access Journals (Sweden)

    A Seyed Ahmadi

    2015-07-01

    Full Text Available To evaluate canola cultivars response to physiological characteristics and grain yield end seasonal drought stress in weather condition of Ahvaz, farm experiments were done at research farm of Khuzestan agriculture and natural resources center. During 2007-2008 and 2008-2009 crop years. Farm test comprised drought stress was done as split plot form with randomize complete block design with four replication, treatments consist of drought stress (main factor including 50, 60 and 70 percent of water use content, which was applied from early heading stage until physiological maturity, and three spring canola cultivar including Shirali, Hayola 401 and R.G.S. were considered as sub plots. Measurements include biological yield, grain yield, harvesting index, number of pod per plant 1000 grain weight, number of grain in pod, plant height, and stem diameter, oil and protein percentage. Results showed that drought stress reduced significantly grain yield, biological yield, harvest index and the average of reduction of them during 2 years for per unit reduce moisture from 50% to 70% were 2, 1.35, and 0.81 percent, respectively. During two years, 1000 grain weight, number of pods per plant and number of grain per pod reduced 27, 36 and 20 percent, respectively. Terminal Drought stress reduced significantly plant height, stem diameter, stem number per plant and pod length, this reduced were 12, 46, 36 and 14 percent, respectively. Stem diameter, and stem number per plant reduced more than other characteristics. In this study oil grain decreased 12 % and protein grain increased 18.5% but oil and protein yield decreased 44.9% and 27.1% respectively..Finally, in weather condition of Khuzestan, terminal drought stress on February and March in which has simultaneous with early flowering stage and filling seed, significantly, reduced yield and compounded yield and affects on stem growth and qualities oil and protein negatively. Therefore, with irrigation

  5. 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

  6. 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

  7. Kunitz Proteinase Inhibitors Limit Water Stress Responses in White Clover (Trifolium repens L.) Plants.

    Science.gov (United States)

    Islam, Afsana; Leung, Susanna; Nikmatullah, Aluh; Dijkwel, Paul P; McManus, Michael T

    2017-01-01

    The response of plants to water deficiency or drought is a complex process, the perception of which is triggered at the molecular level before any visible morphological responses are detected. It was found that different groups of plant proteinase inhibitors (PIs) are induced and play an active role during abiotic stress conditions such as drought. Our previous work with the white clover ( Trifolium repens L.) Kunitz Proteinase Inhibitor ( Tr-KPI ) gene family showed that Tr-KPIs are differentially regulated to ontogenetic and biotic stress associated cues and that, at least some members of this gene family may be required to maintain cellular homeostasis. Altered cellular homeostasis may also affect abiotic stress responses and therefore, we aimed to understand if distinct Tr-PKI members function during drought stress. First, the expression level of three Tr-KPI genes, Tr-KPI1 , Tr-KPI2 , and Tr-KPI5 , was measured in two cultivars and one white clover ecotype with differing capacity to tolerate drought. The expression of Tr-KPI1 and Tr-KPI5 increased in response to water deficiency and this was exaggerated when the plants were treated with a previous period of water deficiency. In contrast, proline accumulation and increased expression of Tr-NCED1 , a gene encoding a protein involved in ABA biosynthesis, was delayed in plants that experienced a previous drought period. RNAi knock-down of Tr-KPI1 and Tr-KPI5 resulted in increased proline accumulation in leaf tissue of plants grown under both well-watered and water-deficit conditions. In addition, increased expression of genes involved in ethylene biosynthesis was found. The data suggests that Tr-KPIs , particularly Tr-KPI5 , have an explicit function during water limitation. The results also imply that the Tr-KPI family has different in planta proteinase targets and that the functions of this protein family are not solely restricted to one of storage proteins or in response to biotic stress.

  8. Kunitz Proteinase Inhibitors Limit Water Stress Responses in White Clover (Trifolium repens L. Plants

    Directory of Open Access Journals (Sweden)

    Afsana Islam

    2017-10-01

    Full Text Available The response of plants to water deficiency or drought is a complex process, the perception of which is triggered at the molecular level before any visible morphological responses are detected. It was found that different groups of plant proteinase inhibitors (PIs are induced and play an active role during abiotic stress conditions such as drought. Our previous work with the white clover (Trifolium repens L. Kunitz Proteinase Inhibitor (Tr-KPI gene family showed that Tr-KPIs are differentially regulated to ontogenetic and biotic stress associated cues and that, at least some members of this gene family may be required to maintain cellular homeostasis. Altered cellular homeostasis may also affect abiotic stress responses and therefore, we aimed to understand if distinct Tr-PKI members function during drought stress. First, the expression level of three Tr-KPI genes, Tr-KPI1, Tr-KPI2, and Tr-KPI5, was measured in two cultivars and one white clover ecotype with differing capacity to tolerate drought. The expression of Tr-KPI1 and Tr-KPI5 increased in response to water deficiency and this was exaggerated when the plants were treated with a previous period of water deficiency. In contrast, proline accumulation and increased expression of Tr-NCED1, a gene encoding a protein involved in ABA biosynthesis, was delayed in plants that experienced a previous drought period. RNAi knock-down of Tr-KPI1 and Tr-KPI5 resulted in increased proline accumulation in leaf tissue of plants grown under both well-watered and water-deficit conditions. In addition, increased expression of genes involved in ethylene biosynthesis was found. The data suggests that Tr-KPIs, particularly Tr-KPI5, have an explicit function during water limitation. The results also imply that the Tr-KPI family has different in planta proteinase targets and that the functions of this protein family are not solely restricted to one of storage proteins or in response to biotic stress.

  9. 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.

  10. Effect of phosphate solubilizing microorganisms on quantitative and qualitative characteristics of maize (Zea mays L.) under water deficit stress.

    Science.gov (United States)

    Ehteshami, S M R; Aghaalikhani, M; Khavazi, K; Chaichi, M R

    2007-10-15

    The effect of seed inoculation by phosphate solubilizing microorganisms on growth, yield and nutrient uptake of maize (Zea mays L. SC. 704) was studied in a field experiment. Positive effect on plant growth, nutrient uptake, grain yield and yield components in maize plants was recorded in the treatment receiving mixed inoculum of Glomus intraradices (AM) and Pseudomonas fluorescens (Pf). Co-inoculation treatment significantly increased grain yield, yield components, harvest index, grain N and P, soil available P, root colonization percentage and crop WUE under water deficit stress. In some of investigated characteristics under well-watered conditions, chemical fertilizer treatment was higher than double inoculated treatments, but this difference was not significant. Seed inoculation only with AM positively affected the measured parameters as amount as co-inoculated treatments. According to the results showed in contrast to the inoculated treatments with AM+Pf and AM, the application of alone Pf caused a comparatively poor response. Therefore, this microorganism needs to a complement for its activity in soil. All of measured parameters in inoculated treatments were higher than uninoculated treatments under water deficit stress conditions. Furthermore, the investigated characteristics of co-inoculated plants under severe water deficit stress conditions were significantly lower than co-inoculated plants under well-watered and moderate-stressed conditions. Therefore it could be stated, these microorganisms need more time to fix and establishing themselves in soil. The present finding showed that phosphate-solubilizing microorganisms can interact positively in promoting plant growth as well as P uptake of maize plants, leading to plant tolerance improving under water deficit stress conditions.

  11. Stress reaction in crayfish: chlorides help to withstand stress in high nitrite concentration conditions – preliminary study

    Directory of Open Access Journals (Sweden)

    Kozák P.

    2011-06-01

    Full Text Available A non-invasive method of recording cardiac activity (heart rate – HR and stress reaction (stress index – SI was used to understand the immediate and ongoing stress reaction of crayfish to the chemical stimuli. This method detects changes in the shape and amplitude parameters of the response to the stress factors, which characterized the crayfish functional state. Experimental animals (Astacus leptodactylus were divided to the two groups with (400 mg·L-1 Cl− and without added chlorides and then exposed to a stepwise increased level of nitrite to the final (sublethal-lethal concentration of 60 mg·L-1 N-NO\\hbox{$_{2}^{-}$}−2 within 24 hours. The course of crayfish reaction was evident and provided information about their reaction to the sublethal-lethal concentration over time. As expected, a less prominent stress reaction was detected in the group with chlorides. The non-invasive method successfully evaluated the sensing of chemical stimuli in water through HR and SI changes.

  12. Translocation of 14C-photosynthates under normal and moisture stress conditions in finger millet (Eleusine coracana) gaertin

    International Nuclear Information System (INIS)

    Udayakumar, M.; Rama Rao, S.; Krishna Sastry, K.S.

    1981-01-01

    Translocation of photosynthates into different sinks was studied following feeding a single leaf with 14 CO 2 in 40 day old stressed and non-stressed plants of Eleusine coracana. The rate of efflux of 14 C-photosynthates was twice as much in non-stressed plants compared to stressed plants. Young developing leaves, stem apex and stem which are the potential sinks under non-stressed conditions received very little activity under stress conditions. Percent activity in the roots was enhanced under stress suggesting the pattern of translocation was altered under stress conditions. In the plants subjected to moisture stress, after feeding with 14 CO 2 the rate of efflux of 14 C-photosynthates from the fed leaf decreased and the pattern of translocation was altered. Though the effect of stress seems to be directly on the translocation system, the photosynthetic rate appears to be more sensitive to stress than translocation. (author)

  13. Occupational stress, working condition and nutritional status of military police officers.

    Science.gov (United States)

    Santana, Angela Maria C; Gomes, Josiane Keila V; De Marchi, Dione; Girondoli, Yassana M; Rosado, Lina E F P de Lima; Rosado, Gilberto Paixão; de Andrade, Isabel Maria

    2012-01-01

    This study aimed to investigate the relationship between stress, working conditions and the nutritional status of 53 military police officers in a Southeast city of Brazil. In order to evaluate the symptomatology and the stress phase, the Inventory of Stress Symptoms Lipp for Adults - ISSL was utilized. The assessment of the working conditions was performed by means of socio-demographic questionnaire, direct observation and interviews. The nutritional and health conditions were assessed through anthropometric measures, biochemical tests, blood pressure measurements and cardiovascular disease risk calculator. The sample is of the male gender (92.5%) and aging below 40 years old (73.6%). From these, 35.8% showed stress and 68.4% were in the resistance phase, with 31.6% almost burned out. Through the calculation of Chi-square we could find positive association between the BMI and tiredness (P = 0.0188), between the BMI and irritation (P = 0.0005) and the BMI and the appearance of nervous system problems or emotional problems (P = 0.0304), indicating that these statuses or problems could be related to work. We can conclude then, the stress is present among military police officers. No case of critical stress was found, and the stress phases identified are still susceptible to intervention.

  14. Effects of strain rate, stress condition and environment on iodine embrittlement of Ziracloy-2

    International Nuclear Information System (INIS)

    Une, K.

    1979-01-01

    Iodine stress corrosion cracking (SCC) susceptibility of Zircaloy became higher with decreasing strain rate. Critical strain rate, below which high SCC severity was observed, substantially depended on Zircaloy stress condition. This strain rate (7 x 10 -3 min -1 ) under plane strain condition was about 3.5 times as fast as that (2 x 10 -3 min -1 ) under uniaxial condition. The maximum iodine embrittlement in Zircaloy was found in stress ratio α (axial/tangential stress) range of 0.5 to 0.7. No embrittlement occurred at α = infinity because of its texture effect. The SCC fracture stresses were about 39 kg/mm 2 for unirradiated and stress-relieved material, and about 34 kg/mm 2 for recrystallized material, whose ratios to yield strength of each material were 0.8 and 1.2. Impurity gases of oxygen and moisture in the iodine had the effects of reducing Zircaloy SCC susceptibility. Stress-relieved material was more sensitive to environmental impurities than recrystallized material

  15. 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.

  16. Acute immobilization stress following contextual fear conditioning reduces fear memory: timing is essential.

    Science.gov (United States)

    Uwaya, Akemi; Lee, Hyunjin; Park, Jonghyuk; Lee, Hosung; Muto, Junko; Nakajima, Sanae; Ohta, Shigeo; Mikami, Toshio

    2016-02-24

    Histone acetylation is regulated in response to stress and plays an important role in learning and memory. Chronic stress is known to deteriorate cognition, whereas acute stress facilitates memory formation. However, whether acute stress facilitates memory formation when it is applied after fear stimulation is not yet known. Therefore, this study aimed to investigate the effect of acute stress applied after fear training on memory formation, mRNA expression of brain-derived neurotrophic factor (BDNF), epigenetic regulation of BDNF expression, and corticosterone level in mice in vivo. Mice were subjected to acute immobilization stress for 30 min at 60 or 90 min after contextual fear conditioning training, and acetylation of histone 3 at lysine 14 (H3K14) and level of corticosterone were measured using western blot analysis and enzyme-linked immunosorbent assay (ELISA), respectively. A freezing behavior test was performed 24 h after training, and mRNA expression of BDNF was measured using real-time polymerase chain reactions. Different groups of mice were used for each test. Freezing behavior significantly decreased with the down-regulation of BDNF mRNA expression caused by acute immobilization stress at 60 min after fear conditioning training owing to the reduction of H3K14 acetylation. However, BDNF mRNA expression and H3K14 acetylation were not reduced in animals subjected to immobilization stress at 90 min after the training. Further, the corticosterone level was significantly high in mice subjected to immobilization stress at 60 min after the training. Acute immobilization stress for 30 min at 60 min after fear conditioning training impaired memory formation and reduced BDNF mRNA expression and H3K14 acetylation in the hippocampus of mice owing to the high level of corticosterone.

  17. Effects of Stress and Sex on Acquisition and Consolidation of Human Fear Conditioning

    Science.gov (United States)

    Kuhn, Cynthia M.; LaBar, Kevin S.; Zorawski, Michael; Blanding, Nineequa Q.

    2006-01-01

    We examined the relationship between stress hormone (cortisol) release and acquisition and consolidation of conditioned fear learning in healthy adults. Participants underwent acquisition of differential fear conditioning, and consolidation was assessed in a 24-h delayed extinction test. The acquisition phase was immediately followed by an 11-min…

  18. Global Transcriptional Responses to Osmotic, Oxidative, and Imipenem Stress Conditions in Pseudomonas putida.

    Science.gov (United States)

    Bojanovič, Klara; D'Arrigo, Isotta; Long, Katherine S

    2017-04-01

    Bacteria cope with and adapt to stress by modulating gene expression in response to specific environmental cues. In this study, the transcriptional response of Pseudomonas putida KT2440 to osmotic, oxidative, and imipenem stress conditions at two time points was investigated via identification of differentially expressed mRNAs and small RNAs (sRNAs). A total of 440 sRNA transcripts were detected, of which 10% correspond to previously annotated sRNAs, 40% to novel intergenic transcripts, and 50% to novel transcripts antisense to annotated genes. Each stress elicits a unique response as far as the extent and dynamics of the transcriptional changes. Nearly 200 protein-encoding genes exhibited significant changes in all stress types, implicating their participation in a general stress response. Almost half of the sRNA transcripts were differentially expressed under at least one condition, suggesting possible functional roles in the cellular response to stress conditions. The data show a larger fraction of differentially expressed sRNAs than of mRNAs with >5-fold expression changes. The work provides detailed insights into the mechanisms through which P. putida responds to different stress conditions and increases understanding of bacterial adaptation in natural and industrial settings. IMPORTANCE This study maps the complete transcriptional response of P. putida KT2440 to osmotic, oxidative, and imipenem stress conditions at short and long exposure times. Over 400 sRNA transcripts, consisting of both intergenic and antisense transcripts, were detected, increasing the number of identified sRNA transcripts in the strain by a factor of 10. Unique responses to each type of stress are documented, including both the extent and dynamics of the gene expression changes. The work adds rich detail to previous knowledge of stress response mechanisms due to the depth of the RNA sequencing data. Almost half of the sRNAs exhibit significant expression changes under at least one

  19. 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.

  20. The effect of heat stress and other factors on total body water and some blood constituents in lactating goats

    International Nuclear Information System (INIS)

    Haggag, A.M.A.

    1988-01-01

    Goats mostly live in the desert or semidesert areas in egypt. Such areas are under adverse environmental conditions. They represent indispensable source of meat and milk for the natives of these areas . Few studies are carried out on goats in connection with their biochemical and physiological response to the high environmental temperature. The present investigation carried out was constructed to study the state of heat stress(35 C and 25% ) in nine Baladi lactating goats as compared with the reactions under mild conditions (15 C and 50% RH). Animals were Kept under each of these controlled conditions for 7 days - eight hours / day. The study included blood haemoglobin level, erythrocyte count, haematocrit value, serum activity of alkaline and acid phosphatases, creatinine, urea and prolactin. The effect of heat stress on body water content and water turnover rate using tritiated water diulation technique was studied

  1. 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:.

  2. Melatonin Modulates Neuronal Cell Death Induced by Endoplasmic Reticulum Stress under Insulin Resistance Condition.

    Science.gov (United States)

    Song, Juhyun; Kim, Oh Yoen

    2017-06-10

    Insulin resistance (IR) is an important stress factor in the central nervous system, thereby aggravating neuropathogenesis and triggering cognitive decline. Melatonin, which is an antioxidant phytochemical and synthesized by the pineal gland, has multiple functions in cellular responses such as apoptosis and survival against stress. This study investigated whether melatonin modulates the signaling of neuronal cell death induced by endoplasmic reticulum (ER) stress under IR condition using SH-SY5Y neuroblastoma cells. Apoptosis cell death signaling markers (cleaved Poly [ADP-ribose] polymerase 1 (PARP), p53, and Bax) and ER stress markers (phosphorylated eIF2α (p-eIF2α), ATF4, CHOP, p-IRE1 , and spliced XBP1 (sXBP1)) were measured using reverse transcription-PCR, quantitative PCR, and western blottings. Immunofluorescence staining was also performed for p-ASK1 and p-IRE1 . The mRNA or protein expressions of cell death signaling markers and ER stress markers were increased under IR condition, but significantly attenuated by melatonin treatment. Insulin-induced activation of ASK1 ( p-ASK1 ) was also dose dependently attenuated by melatonin treatment. The regulatory effect of melatonin on neuronal cells under IR condition was associated with ASK1 signaling. In conclusion, the result suggested that melatonin may alleviate ER stress under IR condition, thereby regulating neuronal cell death signaling.

  3. 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:.

  4. 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 ...

  5. 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...

  6. Literature Survey on the Stress Corrosion Cracking of Low-Alloy Steels in High Temperature Water

    Energy Technology Data Exchange (ETDEWEB)

    Seifert, H.P

    2002-02-01

    The present report is a summary of a literature survey on the stress corrosion cracking (SCC) behaviour/ mechanisms in low-alloy steels (LAS) in high-temperature water with special emphasis to primary-pressure-boundary components of boiling water reactors (BWR). A brief overview on the current state of knowledge concerning SCC of low-alloy reactor pressure vessel and piping steels under BWR conditions is given. After a short introduction on general aspects of SCC, the main influence parameter and available quantitative literature data concerning SCC of LAS in high-temperature water are discussed on a phenomenological basis followed by a summary of the most popular SCC models for this corrosion system. The BWR operating experience and service cracking incidents are discussed with respect to the existing laboratory data and background knowledge. Finally, the most important open questions and topics for further experimental investigations are outlined. (author)

  7. 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.

  8. Hydrologic conditions, recharge, and baseline water quality of the surficial aquifer system at Jekyll Island, Georgia, 2012-13

    Science.gov (United States)

    Gordon, Debbie W.; Torak, Lynn J.

    2016-03-08

    An increase of groundwater withdrawals from the surficial aquifer system on Jekyll Island, Georgia, prompted an investigation of hydrologic conditions and water quality by the U.S. Geological Survey during October 2012 through December 2013. The study demonstrated the importance of rainfall as the island’s main source of recharge to maintain freshwater resources by replenishing the water table from the effects of hydrologic stresses, primarily evapotranspiration and pumping. Groundwater-flow directions, recharge, and water quality of the water-table zone on the island were investigated by installing 26 shallow wells and three pond staff gages to monitor groundwater levels and water quality in the water-table zone. Climatic data from Brunswick, Georgia, were used to calculate potential maximum recharge to the water-table zone on Jekyll Island. A weather station located on the island provided only precipitation data. Additional meteorological data from the island would enhance potential evapotranspiration estimates for recharge calculations.

  9. 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)

  10. Stress corrosion cracking behavior of annealed and cold worked 316L stainless steel in supercritical water

    Energy Technology Data Exchange (ETDEWEB)

    Sáez-Maderuelo, A., E-mail: alberto.saez@ciemat.es; Gómez-Briceño, D.

    2016-10-15

    Highlights: • The alloy 316L is susceptible to stress corrosion cracking in supercritical water. • The susceptibility of alloy 316L increases with temperature and plastic deformation. • Dynamic strain ageing processes may be active in the material. - Abstract: The supercritical water reactor (SCWR) is one of the more promising designs considered by the Generation IV International Forum due to its high thermal efficiency and improving security. To build this reactor, standardized structural materials used in light water reactors (LWR), like austenitic stainless steels, have been proposed. These kind of materials have shown an optimum behavior to stress corrosion cracking (SCC) under LWR conditions except when they are cold worked. It is known that physicochemical properties of water change sharply with pressure and temperature inside of the supercritical region. Owing to this situation, there are several doubts about the behavior of candidate materials like austenitic stainless steel 316L to SCC in the SCWR conditions. In this work, alloy 316L was studied in deaerated SCW at two different temperatures (400 °C and 500 °C) and at 25 MPa in order to determine how changes in this variable influence the resistance of this material to SCC. The influence of plastic deformation in the behavior of alloy 316L to SCC in SCW was also studied at both temperatures. Results obtained from these tests have shown that alloy 316L is susceptible to SCC in supercritical water reactor conditions where the susceptibility of this alloy increases with temperature. Moreover, prior plastic deformation of 316L SS increased its susceptibility to environmental cracking in SCW.

  11. Research on mutant barley population under biotic and abiotic stress condition

    International Nuclear Information System (INIS)

    Peskircioglu, H.; Tuyluer, I.; Sagel, Z.; Kunter, B.; Kantoglu, Y.

    2009-01-01

    Barley is one of the most important cereal with 8,5 million tons production, 3,5 million hectares of sowing area in Turkey which is also one of the gene centres of barley. Barley is grown in every regions of Turkey where climatic conditions are available for the crop. But barley is the predominant crop in the driest land areas throughout the Anatolian plateau. Winters on that plateau are especially severe. Summers are hot and dry with temperatures above 30 degree C. Annual precipitation averages about 300 to 400 millimeters and rains mainly in winter. Because of all of these prerequisite conditions, winter barley dominates in Turkey, which indirectly refers to water economy. According to the above mentioned reasons the objectives of this investigation were: 1) Improvement of drought resistance, loading resistance and high yielding barley varieties by mutation breeding in Central Anatolian Region. 2) Determination and selection of abiotic stress such as salt resistance In our barley mutation breeding programme under Central Anatolian conditions well adapted Tokak 157/37 variety has been used. We applied 250 Gy-300 Gy gamma ray doses . Selection began at M 2 generation. Agronomical characters including earliness, straw length, lodging resistance and disease resistance are monitored in the field and greenhouse. Mutant lines have been tested for salt resistance in the hydrophonic culture which contains 180 mMol and 220 mMol NaCl concentrations. Preliminary yield trial and advanced yield trial are started after M 4 generations. In M 6 generation, we had some desirable lines those are 25-30 days earlier than its parents, so these lines escape from drought period. Some lines that have grown in the hydrophonic cultures, contains 180mMol NaCl still surviving.

  12. Leaf water relations and net gas exchange responses of salinized Carrizo citrange seedlings during drought stress and recovery.

    Science.gov (United States)

    Pérez-Pérez, J G; Syvertsen, J P; Botía, P; García-Sánchez, F

    2007-08-01

    Since salinity and drought stress can occur together, an assessment was made of their interacting effects on leaf water relations, osmotic adjustment and net gas exchange in seedlings of the relatively chloride-sensitive Carrizo citrange, Citrus sinensis x Poncirus trifoliata. Plants were fertilized with nutrient solution with or without additional 100 mm NaCl (salt and no-salt treatments). After 7 d, half of the plants were drought stressed by withholding irrigation water for 10 d. Thus, there were four treatments: salinized and non-salinized plants under drought-stress or well-watered conditions. After the drought period, plants from all stressed treatments were re-watered with nutrient solution without salt for 8 d to study recovery. Leaf water relations, gas exchange parameters, chlorophyll fluorescence, proline, quaternary ammonium compounds and leaf and root concentrations of Cl(-) and Na(+) were measured. Salinity increased leaf Cl(-) and Na(+) concentrations and decreased osmotic potential (Psi(pi)) such that leaf relative water content (RWC) was maintained during drought stress. However, in non-salinized drought-stressed plants, osmotic adjustment did not occur and RWC decreased. The salinity-induced osmotic adjustment was not related to any accumulation of proline, quaternary ammonium compounds or soluble sugars. Net CO(2) assimilation rate (A(CO2)) was reduced in leaves from all stressed treatments but the mechanisms were different. In non-salinized drought-stressed plants, lower A(CO2) was related to low RWC, whereas in salinized plants decreased A(CO2) was related to high levels of leaf Cl(-) and Na(+). A(CO2) recovered after irrigation in all the treatments except in previously salinized drought-stressed leaves which had lower RWC and less chlorophyll but maintained high levels of Cl(-), Na(+) and quaternary ammonium compounds after recovery. High leaf levels of Cl(-) and Na(+) after recovery apparently came from the roots. Plants preconditioned by

  13. Improving Wheat Growth and Yield Using Chlormequat Chloride, Salicylic Acid and Jasmonic Acid under Water Stress

    Directory of Open Access Journals (Sweden)

    N Vahabi

    2017-06-01

    Full Text Available Introduction Drought stress is most important abiotic stress reducing growth and production of wheat worldwide. Protective role of plant growth regulators (PGRs against drought stress has been accepted in general, however, comparison of PGRs types to determine the optimum one is crucial. Many PGRs are known to alleviate the negative effects of drought stress in plants. However, limited research has been conducted to investigate the potential benefits of exogenous application of different PGRs in wheat plants grown under drought stress. Chlormequat chloride (CCC, salicylic acid (SA and jasmonic acid (JA could consider as three major PGRs using in cereals. Materials and Methods To examine the effect of three PGRs consisted of CCC, SA and JA on yield components and grain yield of wheat cv. Roshan under different water stress conditions (a range of light to severe drought levels two separated experiments were conducted at controlled and field conditions at College of Agriculture, Shiraz University during 2012-2013 growing seasons. Concentration of CCC, SA and JA were 19.0, 1.0 and 0.1 mM, respectively. Drought stress levels were 100%, 80%, 60% and 40% of field capacity in greenhouse and were 100%, 2/3 and 1/5 of field capacity in the field experiment. Field capacity was determined as 25% (g g-1 for the experimental field. Greenhouse and field researches were carried out in factorial experiment based on completely randomized design and in split plot experiment based on randomized complete block design, respectively. Four and three replications were used greenhouse and field experiments, respectively. Roshan as a bread wheat cultivar with standard height was used. Foliar application of 3 PGRs was done at double ridges stage in both experiments; however, irrigation treatments were applied at double ridges stage and early anthesis at greenhouse and field experiment, respectively. For plot irrigation a tape system was used and amount of irrigation was

  14. Effect of constraint condition and internal medium on residual stress under overlay welding for dissimilar metal welding

    International Nuclear Information System (INIS)

    Song, Tae Kwang; Kim, Yun Jae; Lee, Kyoung Soo; Park, Chi Yong; Kim, Jong Sung; Kim, Jin Weon

    2007-01-01

    In nuclear power plants, residual stress of dissimilar metal weld propagates cracks in the weld metal which is susceptible to stress corrosion cracking. Overlay welding is a process widely used to mitigate residual stress replacing inside tensile stress by compression stress. However, according to the result of this study the effect of overlay welding on residual stress depends on both internal medium and constraint condition. The purpose of this study is to maximize the positive effect of overlay welding by finite element analyses

  15. Abscisic Acid Accumulation by Roots of Xanthium strumarium L. and Lycopersicon esculentum Mill. in Relation to Water Stress 1

    Science.gov (United States)

    Cornish, Katrina; Zeevaart, Jan A. D.

    1985-01-01

    Plants of Xanthium strumarium L. and Lycopersicon esculentum Mill. cv `Rheinlands Ruhm' were grown in solution culture, and control and steam-girdled intact plants were stressed. Detached roots of both species were stressed to different extents in two ways: (a) either in warm air or, (b) in the osmoticum Aquacide III. The roots of both species produced and accumulated progressively more abscisic acid (ABA), the greater the stress inflicted by either method. ABA-glucose ester levels in Xanthium roots were not affected by water stress and were too low to be the source of the stress-induced ABA. The fact that ABA accumulated in detached roots and in roots of girdled plants proves that ABA was synthesized in the roots and not merely transported from the shoots. Maximum ABA accumulation in detached roots occurred after 60 to 70% loss of fresh weight. In Xanthium roots, ABA levels continued to increase for at least 11 hours, and no catabolism was apparent when stressed roots were immersed in water, although the roots did stop accumulating ABA. When osmotically stressed, Xanthium roots reached a maximum ABA level after 2 hours, but ABA continued to rise in the medium. Under optimal stress conditions, endogenous ABA levels increased 100 times over their prestress values in detached roots of Xanthium, and 15 times in Lycopersicon under nonoptimal stress, when endogenous ABA was expressed as concentrations based on tissue water content. These are much greater relative increases than observed in the leaves (15 times in Xanthium, 3 times in Lycopersicon), although the roots contain substantially less ABA than the leaves in all circumstances. The results suggest that the endogenous level of ABA in roots could rise appreciably prior to leaf wilt, and could modify the plant's water economy before the leaves become stressed. PMID:16664467

  16. Abscisic Acid Accumulation by Roots of Xanthium strumarium L. and Lycopersicon esculentum Mill. in Relation to Water Stress.

    Science.gov (United States)

    Cornish, K; Zeevaart, J A

    1985-11-01

    Plants of Xanthium strumarium L. and Lycopersicon esculentum Mill. cv ;Rheinlands Ruhm' were grown in solution culture, and control and steam-girdled intact plants were stressed. Detached roots of both species were stressed to different extents in two ways: (a) either in warm air or, (b) in the osmoticum Aquacide III. The roots of both species produced and accumulated progressively more abscisic acid (ABA), the greater the stress inflicted by either method. ABA-glucose ester levels in Xanthium roots were not affected by water stress and were too low to be the source of the stress-induced ABA. The fact that ABA accumulated in detached roots and in roots of girdled plants proves that ABA was synthesized in the roots and not merely transported from the shoots.Maximum ABA accumulation in detached roots occurred after 60 to 70% loss of fresh weight. In Xanthium roots, ABA levels continued to increase for at least 11 hours, and no catabolism was apparent when stressed roots were immersed in water, although the roots did stop accumulating ABA. When osmotically stressed, Xanthium roots reached a maximum ABA level after 2 hours, but ABA continued to rise in the medium.Under optimal stress conditions, endogenous ABA levels increased 100 times over their prestress values in detached roots of Xanthium, and 15 times in Lycopersicon under nonoptimal stress, when endogenous ABA was expressed as concentrations based on tissue water content. These are much greater relative increases than observed in the leaves (15 times in Xanthium, 3 times in Lycopersicon), although the roots contain substantially less ABA than the leaves in all circumstances. The results suggest that the endogenous level of ABA in roots could rise appreciably prior to leaf wilt, and could modify the plant's water economy before the leaves become stressed.

  17. Variation in relative water content, proline accumulation and stress gene expression in two cowpea landraces under drought.

    Science.gov (United States)

    Zegaoui, Zahia; Planchais, Séverine; Cabassa, Cécile; Djebbar, Reda; Abrous Belbachir, Ouzna; Carol, Pierre

    2017-11-01

    Many landraces of cowpea [Vigna unguiculata (L.) Walp.] are adapted to particular geographical and climatic conditions. Here we describe two landraces grown respectively in arid and temperate areas of Algeria and assess their physiological and molecular responses to drought stress. As expected, when deprived of water cowpea plants lose water over time with a gradual reduction in transpiration rate. The landraces differed in their relative water content (RWC) and whole plant transpiration rate. The landrace from Menia, an arid area, retained more water in adult leaves. Both landraces responded to drought stress at the molecular level by increasing expression of stress-related genes in aerial parts, including proline metabolism genes. Expression of gene(s) encoding proline synthesis enzyme P5CS was up regulated and gene expression of ProDH, a proline catabolism enzyme, was down regulated. Relatively low amounts of proline accumulated in adult leaves with slight differences between the two landraces. During drought stress the most apical part of plants stayed relatively turgid with a high RWC compared to distal parts that wilted. Expression of key stress genes was higher and more proline accumulated at the apex than in distal leaves indicating that cowpea has a non-uniform stress response at the whole plant level. Our study reveals a developmental control of water stress through preferential proline accumulation in the upper tier of the cowpea plant. We also conclude that cowpea landraces display physiological adaptations to water stress suited to the arid and temperate climates in which they are cultivated. Copyright © 2017 Elsevier GmbH. All rights reserved.

  18. A Transdiagnostic Minority Stress Treatment Approach for Gay and Bisexual Men’s Syndemic Health Conditions

    Science.gov (United States)

    Pachankis, John E.

    2015-01-01

    Developing and deploying separate treatments for separate conditions seems ill-suited to intervening upon the co-occurring, and possibly functionally similar, psychosocial conditions facing gay and bisexual men. This article argues for the need to create transdiagnostic interventions that reduce multiple syndemic conditions facing gay and bisexual men at the level of their shared source in minority stress pathways. This article first reviews psychosocial syndemic conditions affecting gay and bisexual men, then suggests pathways that might link minority stress to psychosocial syndemics based on recent advancements in emotion science, psychiatric nosology, and cognitive-affective neuroscience, and finally suggests cross-cutting psychosocial treatment principles to reduce minority stress–syndemic pathways among gay and bisexual men. Because minority stress serves as a common basis of all psychosocial syndemic conditions reviewed here, locating the pathways through which minority stress generates psychosocial syndemics and employing overarching treatment principles capable of simultaneously alleviating these pathways will ultimately create a transdiagnostic approach to improving gay and bisexual men’s health. Clinical research and training approaches are suggested to further validate the pathways suggested here, establish the efficacy of treatment approaches tied to those pathways, and generate effective methods for disseminating a transdiagnostic minority stress treatment approach for gay and bisexual men’s psychosocial syndemic health. PMID:26123065

  19. Difference in canopy and air temperature as an indicator of grassland water stress

    International Nuclear Information System (INIS)

    Duffková, R.

    2006-01-01

    In 2003–2005 in conditions of the moderately warm region of the Třeboň Basin (Czech Republic) the difference between canopy temperature (T c ) and air temperature at 2 m (T a ) was tested as an indicator of grassland water stress. To evaluate water stress ten-minute averages of temperature difference T c –T a were chosen recorded on days without rainfall with intensive solar radiation from 11.00 to 14.00 CET. Water stress in the zone of the major portion of root biomass (0–0.2 m) in the peak growing season (minimum presence of dead plant residues) documented by a sudden increase in temperature difference, its value 5–12°C and unfavourable canopy temperatures due to overheating (> 30°C) was indicated after high values of suction pressure approaching the wilting point (1300 kPa) were reached. High variability of temperature difference in the conditions of sufficient supply of water to plants was explained by the amount of dead plant residues in canopy, value of vapour pressure deficit (VPD), actual evapotranspiration rate (ETA) and soil moisture content. At the beginning of the growing season (presence of dead plant residues and voids) we proved moderately strong negative linear correlations of T c –T a with VPD and T c –T a with ETA rate and moderately strong positive linear correlations of ETA rate with VPD. In the period of intensive growth (the coverage of dead plant residues and voids lower than 10%) moderately strong linear correlations of T c –T a with VPD and multiple linear correlations of T c –T a with VPD and soil moisture content at a depth of 0.10–0.40 m were demonstrated. (author)

  20. Monitoring psychosocial stress at work: development of the Psychosocial Working Conditions Questionnaire.

    Science.gov (United States)

    Widerszal-Bazyl, M; Cieślak, R

    2000-01-01

    Many studies on the impact of psychosocial working conditions on health prove that psychosocial stress at work is an important risk factor endangering workers' health. Thus it should be constantly monitored like other work hazards. The paper presents a newly developed instrument for stress monitoring called the Psychosocial Working Conditions Questionnaire (PWC). Its structure is based on Robert Karasek's model of job stress (Karasek, 1979; Karasek & Theorell, 1990). It consists of 3 main scales Job Demands, Job Control, Social Support and 2 additional scales adapted from the Occupational Stress Questionnaire (Elo, Leppanen, Lindstrom, & Ropponen, 1992), Well-Being and Desired Changes. The study of 8 occupational groups (bank and insurance specialists, middle medical personnel, construction workers, shop assistants, government and self-government administration officers, computer scientists, public transport drivers, teachers, N = 3,669) indicates that PWC has satisfactory psychometrics parameters. Norms for the 8 groups were developed.

  1. Effect of the combined stress on the life of components under thermal cycling conditions

    International Nuclear Information System (INIS)

    Zuchowski, R.; Zietkowski, L.

    1987-01-01

    The life of structural components subjected to temperature changes is affected, among other factors, by the nature of the stress field. If life prediction for axially stressed components can be accomplished with a number of well established techniques, the behaviour under a complex state of stress and varying temperature conditions still is the object of intensive research. The present study was aimed at assessing the influence of the stress field upon the life of specimens made of chromium-nickel H23N18 steel under thermal cycling conditions. The designation of steel is in accordance with Polish Standards. The experiments were made on thin-walled tubular specimens loaded with various combinations of a static axial force and a static torque. (orig./GL)

  2. Life Balance and Stress in Adults With Medical Conditions or Obesity.

    Science.gov (United States)

    Matuska, Kathleen; Bass, Julie

    2016-04-01

    This cross-sectional research examined differences in life balance and perceived stress by body mass index (BMI) levels and self-reported medical conditions that limited physical activity. The sample consisted of 2,338 participants between the ages of 18 and 49 years who took the Life Balance Inventory, the Perceived Stress Scale, and provided demographic information including height and weight. Findings showed that individuals who were obese (BMI > 30.0) reported significantly lower life balance scores and higher stress scores than participants without obesity (p life balance and more stress than individuals without medical conditions (p < .001). These findings highlight the importance of addressing activity participation as a means to promote health and wellness. © The Author(s) 2016.

  3. Measurement of stress distributions in truck tyre contact patch in real rolling conditions

    Science.gov (United States)

    Anghelache, Gabriel; Moisescu, Raluca

    2012-12-01

    Stress distributions on three orthogonal directions have been measured across the contact patch of truck tyres using the complex measuring system that contains a transducer assembly with 30 sensing elements placed in the road surface. The measurements have been performed in straight line, in real rolling conditions. Software applications for calibration, data acquisition, and data processing were developed. The influence of changes in inflation pressure and rolling speed on the shapes and sizes of truck tyre contact patch has been shown. The shapes and magnitudes of normal, longitudinal, and lateral stress distributions, measured at low speed, have been presented and commented. The effect of wheel toe-in and camber on the stress distribution results was observed. The paper highlights the impact of the longitudinal tread ribs on the shear stress distributions. The ratios of stress distributions in the truck tyre contact patch have been computed and discussed.

  4. 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.

  5. A survey of preharvest conditions affecting the regulation of water loss during vase life

    NARCIS (Netherlands)

    Fanourakis, D.; Velez-Ramirez, A.I.; In, B.C.; Barendse, H.; Meeteren, van U.; Woltering, E.J.

    2015-01-01

    Vase life (VL) tests on cut roses obtained from commercial sources were conducted at FloraHolland. Water stress symptoms were the most important criterion terminating VL in 46 out of 50 assessed cultivars. These symptoms appear when water loss exceeds water uptake. Inadequate control of water

  6. The Effect of Water Stress on the Gas Exchange Parameters, Productivity and Seed Health of Buckwheat (Fagopyrum esculentum Moench

    Directory of Open Access Journals (Sweden)

    Agnieszka Pszczółkowska

    2012-12-01

    Full Text Available The present pot experiment studied the effect of different soil moisture contents (60 - 70% CWC (capillary water capacity - control; 30 - 35% CWC - water stress on buckwheat productivity, the gas exchange parameters and health of buckwheat nuts. It was found that water deficit affected adversely certain biometric features investigated (plant height, number of nuts per cluster and caused a decrease in seed weight per plant. It was also shown that water stress reduced the values of the investigated gas exchange parameters (photosynthesis rate, transpiration rate, intercellular-space CO2 concentration, and stomatal conductance relative to the control treatment. Different soil moisture contents did not have a clear effect on fungal colonization of seeds. The multiplex PCR assays did not enable the detection of the genes responsible for mycotoxin synthesis. Under water deficit conditions, an increase was found in the content of albumin and globulin fractions as well as of glutelin fractions.

  7. Impact of controlled release urea on maize yield and nitrogen use efficiency under different water conditions.

    Directory of Open Access Journals (Sweden)

    Guanghao Li

    Full Text Available Controlled release urea (CRU has been widely adopted to increase nitrogen (N use efficiency and maize production, but the impacts can range widely depending on water availability in the soil. In an experiment using Zhengdan 958 (a popular summer maize hybrid, three levels of water treatments (adequate water condition [W3], which maintained soil moisture at about 75% ± 5% of the soil's field capacity; mild water stress [W2], which maintained moisture content at 55% ± 5% of field capacity; and severe water stress [W1], which had a moisture content of 35% ± 5% of field capacity and four levels of controlled release urea fertilizer (N0, N1, N2 and N3 were 0, 105, 210 and 315 kg N ha-1, respectively were compared in a rainout shelter system with soil. The results revealed that CRU had significant effects on maize yields and N use efficiencies under different water conditions. The mean yields increased with increasing water levels and showed significant differences. Under W1, the accumulation of dry matter and N were limited, and N internal efficiency (NIE and the apparent recovery efficiency of applied N (REN decreased with N increases; yields of N1, N2, and N3 were similar. Under W2, the dry matter and N accumulation, as well as the yield, showed an increasing trend with an increase in N application, and the NIE and REN of N3 showed no difference from N2. Under W3, yields of N2 and N3 were similar and they were significantly higher than that of N1, but the agronomic N use efficiency (ANUE, REN, and the physiological NUE (PNUE of N2 were 54.2, 34.9, and 14.4% higher, respectively, than those of N3. N application beyond the optimal N rate did not consistently increase maize yield, and caused a decrease in N use efficiencies. Highest overall dry matter, N accumulation, and yields were observed with N3 under W2, and those showed no differences with N2 and N3 under W3. Under this experimental condition, the CRU of 210 kg ha-1 was optimized when soil

  8. 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.

  9. Root growth, water uptake, and sap flow of winter wheat in response to different soil water conditions

    Science.gov (United States)

    Cai, Gaochao; Vanderborght, Jan; Langensiepen, Matthias; Schnepf, Andrea; Hüging, Hubert; Vereecken, Harry

    2018-04-01

    How much water can be taken up by roots and how this depends on the root and water distributions in the root zone are important questions that need to be answered to describe water fluxes in the soil-plant-atmosphere system. Physically based root water uptake (RWU) models that relate RWU to transpiration, root density, and water potential distributions have been developed but used or tested far less. This study aims at evaluating the simulated RWU of winter wheat using the empirical Feddes-Jarvis (FJ) model and the physically based Couvreur (C) model for different soil water conditions and soil textures compared to sap flow measurements. Soil water content (SWC), water potential, and root development were monitored noninvasively at six soil depths in two rhizotron facilities that were constructed in two soil textures: stony vs. silty, with each of three water treatments: sheltered, rainfed, and irrigated. Soil and root parameters of the two models were derived from inverse modeling and simulated RWU was compared with sap flow measurements for validation. The different soil types and water treatments resulted in different crop biomass, root densities, and root distributions with depth. The two models simulated t