Science.gov

Sample records for water physiological characteristics

  1. [Effects of different irrigations on the water physiological characteristics of Haloxylon ammodendron in Taklimakan Desert hinterland].

    PubMed

    Xie, Ting-ting; Zhang, Xi-ming; Liang, Shao-min; Shan, Li-shan; Yang, Xiao-lin; Hua, Yong-hui

    2008-04-01

    By using heat-balance stem flow gauge and press chamber, the water physiological characteristics of Haloxylon ammodendron under different irrigations in Taklimakan Desert hinterland were measured and analyzed. The results indicated that the diurnal variation curve of H. ammodendron stem sap flow varied with irrigations. When irrigated 35 and 24.5 kg x plant(-1) once time, the diurnal variation of stem sap flow changed in single peak curve and the variation extent was higher; while irrigated 14 kg x plant(-1) once time, the diurnal variation changed in two-peak curve and the variation extent was small. With the decrease of irrigations, the average daily sap flow rate and the daily water consumption of H. ammodendron decreased gradually, the dawn and postmeridian water potential also had a gradual decrease, and the correlations of stem sap flow with total radiation, air temperature, relative humidity, and wind speed enhanced. Under different irrigations, the correlation between stem sap flow rate and total radiation was always the best. PMID:18593026

  2. The effect of water stress on some morphological, physiological, and biochemical characteristics and bud success on apple and quince rootstocks.

    PubMed

    Bolat, Ibrahim; Dikilitas, Murat; Ercisli, Sezai; Ikinci, Ali; Tonkaz, Tahsin

    2014-01-01

    The effects of different water stress (control, medium, and severe) on some morphological, physiological, and biochemical characteristics and bud success of M9 apple and MA quince rootstocks were determined. The results showed that water stress significantly affected most morphological, physiological, and biochemical characteristics as well as budding success on the both rootstocks. The increasing water stress decreased the relative shoot length, diameter, and plant total fresh and dry weights. Leaf relative water content and chlorophyll index decreased while electrolyte leakage increased with the increase of water stress in both rootstocks. An increase in water stress also resulted in reduction in budding success in Vista Bella/M9 (79.33% and 46.67%) and Santa Maria/MA (70.33% and 15.33%) combinations. However, the water stress in Santa Maria/MA was more prominent. The increase in water stress resulted in higher peroxidase activities as well as phenol contents in both rootstocks. Although catalase activity, anthocyanin, and proline contents increased with the impact of stress, this was not statistically significant. The results suggest that the impact of stress increased with the increase of water stress; therefore, growers should be careful when using M9 and MA rootstocks in both nursery and orchards where water scarcity is present. PMID:24741357

  3. Physiological water model development

    NASA Technical Reports Server (NTRS)

    Doty, Susan

    1993-01-01

    The water of the human body can be categorized as existing in two main compartments: intracellular water and extracellular water. The intracellular water consists of all the water within the cells and constitutes over half of the total body water. Since red blood cells are surrounded by plasma, and all other cells are surrounded by interstitial fluid, the intracellular compartment has been subdivided to represent these two cell types. The extracellular water, which includes all of the fluid outside of the cells, can be further subdivided into compartments which represent the interstitial fluid, circulating blood plasma, lymph, and transcellular water. The interstitial fluid surrounds cells outside of the vascular system whereas plasma is contained within the blood vessels. Avascular tissues such as dense connective tissue and cartilage contain interstitial water which slowly equilibrates with tracers used to determine extracellular fluid volume. For this reason, additional compartments are sometimes used to represent these avascular tissues. The average size of each compartment, in terms of percent body weight, has been determined for adult males and females. These compartments and the forces which cause flow between them are presented. The kidneys, a main compartment, receive about 25 percent of the cardiac output and filters out a fluid similar to plasma. The composition of this filtered fluid changes as it flows through the kidney tubules since compounds are continually being secreted and reabsorbed. Through this mechanism, the kidneys eliminate wastes while conserving body water, electrolytes, and metabolites. Since sodium accounts for over 90 percent of the cations in the extracellular fluid, and the number of cations is balanced by the number of anions, considering the renal handling sodium and water only should sufficiently describe the relationship between the plasma compartment and kidneys. A kidney function model is presented which has been adapted from a

  4. Impact of human emotions on physiological characteristics

    NASA Astrophysics Data System (ADS)

    Partila, P.; Voznak, M.; Peterek, T.; Penhaker, M.; Novak, V.; Tovarek, J.; Mehic, Miralem; Vojtech, L.

    2014-05-01

    Emotional states of humans and their impact on physiological and neurological characteristics are discussed in this paper. This problem is the goal of many teams who have dealt with this topic. Nowadays, it is necessary to increase the accuracy of methods for obtaining information about correlations between emotional state and physiological changes. To be able to record these changes, we focused on two majority emotional states. Studied subjects were psychologically stimulated to neutral - calm and then to the stress state. Electrocardiography, Electroencephalography and blood pressure represented neurological and physiological samples that were collected during patient's stimulated conditions. Speech activity was recording during the patient was reading selected text. Feature extraction was calculated by speech processing operations. Classifier based on Gaussian Mixture Model was trained and tested using Mel-Frequency Cepstral Coefficients extracted from the patient's speech. All measurements were performed in a chamber with electromagnetic compatibility. The article discusses a method for determining the influence of stress emotional state on the human and his physiological and neurological changes.

  5. Physiologic Responses to Treadmill and Water Running.

    ERIC Educational Resources Information Center

    Bishop, Phillip A.; And Others

    1989-01-01

    Presents results of a study of the physiological responses of uninjured runners to running on a treadmill and in water. Water running may lessen an injured athlete's rate of deconditioning, but indications are that the metabolic cost of water running is not significantly greater than that of treadmill running. (SM)

  6. Physiological characteristics of international female soccer players.

    PubMed

    Manson, Sarah A; Brughelli, Matt; Harris, Nigel K

    2014-02-01

    The purpose of this study was to investigate the physiological characteristics of Fédération Internationale de Football Association (FIFA) eligible international female soccer players aged 14-36 years and to determine if measures were significantly different for players selected (i.e., starters) to the starting line up for an FIFA tournament as compared with those not selected (i.e., nonstarters). Fifty-one (N = 18 Under 17; N = 18 Under 20; N = 15 Senior) international female soccer players participated in this study. The subjects underwent measurements of anthropometry (height and body mass), lower body strength (isokinetic testing), sprint kinetics and kinematics (nonmotorized treadmill), leg power (unilateral jumping), and maximal aerobic velocity (30:15 intermittent fitness test) during the final preparatory stage for an FIFA event. Outcomes of the age group data indicate that differences in physiological capacities are evident for the Under 17 players as compared with those for the Under 20 and Senior capped international players, suggesting a plateau in the acquisition of physical qualities as players mature. Starters tended to be faster (effect size [ES] = 0.55-1.0, p < 0.05) and have a higher maximal aerobic velocity (ES = 0.78-2.45, p < 0.05), along with greater eccentric leg strength (ES = 0.33-1.67, p < 0.05). Significant differences were detected between starters and nonstarters for isokinetic leg strength (ES = 0.54-1.24, p < 0.05) and maximal aerobic velocity (ES = 0.87, p < 0.05) for Under 17 players, where maximal aerobic velocity was the primary difference between starters and nonstarters (ES = 0.83-2.45, p < 0.05) for the Under 20 and Senior players. Coaches should emphasize the development of speed, maximal aerobic velocity, and leg strength in developing female soccer players. PMID:24476742

  7. FISH PHYSIOLOGY, TOXICOLOGY, AND WATER QUALITY:

    EPA Science Inventory

    Twenty-one participants from Europe, North America and China convened in Chongqing, China, October 12-14, 2005, for the Eighth International Symposium in Fish Physiology, Toxicology and Water Quality. The subject of the meeting was "Hypoxia in vertebrates: Comparisons of terrestr...

  8. FISH PHYSIOLOGY, TOXICOLOGY, AND WATER QUALITY

    EPA Science Inventory

    Scientists from ten countries presented papers at the Fifth International Symposium on Fish Physiology, Toxicology, and Water Quality, which was held on the campus of the city University of Hong Kong on November 10-13, 1998. These Proceedings include 23 papers presented in sessi...

  9. Physiological and clinical characteristics of andropause.

    PubMed

    Delev, Delian P; Kostadinova, Ivanka I; Kostadinov, Ilia D; Ubenova, Dafinka K

    2009-01-01

    The process of aging in man involves a lot of functional and structural changes in the body organs and systems. In this review we shall characterize the physiological and clinical manifestations of andropause. We'll review the physiological basis of the ageing process, the age-related changes in the testosterone secretion regulation, and the dynamics of androgen action and active testosterone metabolism. We also investigate the multifactorial etiology of age-related physiological changes--the body undergoes changes in its structure, there is a loss of muscle strength and decline in physical functions. Sexual dysfunction, hypogonadism and psychological changes are also commonly observed symptoms in this condition. Changes of similar kind can also be seen in young males with androgen deficiency. The age-related changes in physiological functions can potentially lead to some important consequences such as reduced physical activity, higher risk of developing specific diseases (ischemic heart disease, diabetes, osteoporosis), diminished capacity to recover after acute diseases, but most often it leads to increased fracture predisposition. All these may eventually affect negatively the self-care capacity of patients making them require a long-term professional care, and lead to severe psychological and social isolation and increased mortality and change in quality of life. To limit the age-related physiological decline in serum testosterone levels, we should be able to tackle the still unresolved important clinical issue--can hormone replacement therapy administered to elderly men improve their functional status, prevent diseases from developing, improve quality of life and reduce fracture risk. The data included in the present review will contribute to determining the potential benefits and risks of testosterone replacement therapy. PMID:19437894

  10. Physiological characteristics of well-trained junior sprint kayak athletes.

    PubMed

    Borges, Thiago Oliveira; Dascombe, Ben; Bullock, Nicola; Coutts, Aaron J

    2015-07-01

    This study aimed to profile the physiological characteristics of junior sprint kayak athletes (n=21, VO2max 4.1±0.7 L/min, training experience 2.7±1.2 y) and to establish the relationship between physiological variables (VO2max, VO2 kinetics, muscle-oxygen kinetics, paddling efficiency) and sprint kayak performance. VO2max, power at VO2max, power:weight ratio, paddling efficiency, VO2 at lactate threshold, and whole-body and muscle oxygen kinetics were determined on a kayak ergometer in the laboratory. Separately, on-water time trials (TT) were completed over 200 m and 1000 m. Large to nearly perfect (-.5 to -.9) inverse relationships were found between the physiological variables and on-water TT performance across both distances. Paddling efficiency and lactate threshold shared moderate to very large correlations (-.4 to -.7) with 200- and 1000-m performance. In addition, trivial to large correlations (-.11 to -.5) were observed between muscle-oxygenation parameters, muscle and whole-body oxygen kinetics, and performance. Multiple regression showed that 88% of the unadjusted variance for the 200-m TT performance was explained by VO2max, peripheral muscle deoxygenation, and maximal aerobic power (P<.001), whereas 85% of the unadjusted variance in 1000-m TT performance was explained by VO2max and deoxyhemoglobin (P<.001). The current findings show that well-trained junior sprint kayak athletes possess a high level of relative aerobic fitness and highlight the importance of the peripheral muscle metabolism for sprint kayak performance, particularly in 200-m races, where finalists and nonfinalists are separated by very small margins. Such data highlight the relative aerobic-fitness variables that can be used as benchmarks for talent-identification programs or monitoring longitudinal athlete development. However, such approaches need further investigation. PMID:25473923

  11. The Clinical Physiology of Water Metabolism

    PubMed Central

    Weitzman, Richard E.; Kleeman, Charles R.

    1979-01-01

    Water balance is tightly regulated within a tolerance of less than 1 percent by a physiologic control system located in the hypothalamus. Body water homeostasis is achieved by balancing renal and nonrenal water losses with appropriate water intake. The major stimulus to thirst is increased osmolality of body fluids as perceived by osmoreceptors in the anteroventral hypothalamus. Hypovolemia also has an important effect on thirst which is mediated by arterial baroreceptors and by the renin-angiotensin system. Renal water loss is determined by the circulating level of the antidiuretic hormone, arginine vasopressin (AVP). AVP is synthesized in specialized neurosecretory cells located in the supraoptic and paraventricular nuclei in the hypothalamus and is transported in neurosecretory granules down elongated axons to the posterior pituitary. Depolarization of the neurosecretory neurons results in the exocytosis of the granules and the release of AVP and its carrier protein (neurophysin) into the circulation. AVP is secreted in response to a wide variety of stimuli. Change in body fluid osmolality is the most potent factor affecting AVP secretion, but hypovolemia, the renin-angiotensin system, hypoxia, hypercapnia, hyperthermia and pain also have important effects. Many drugs have been shown to stimulate the release of AVP as well. Small changes in plasma AVP concentration of from 0.5 to 4 μU per ml have major effects on urine osmolality and renal water handling. ImagesFigure 5.Figure 12.Figure 15.Figure 16. PMID:394480

  12. Citation Characteristics of Physiology Literature, 1970-72

    ERIC Educational Resources Information Center

    Hafner, A. W.

    1976-01-01

    To identify and describe selected characteristics of the research literature of the basic medical science area of physiology during the three-year period 1970-72, this literature was analyzed to determine where, when, by what subject area, and in what countries it was published. (Author/PF)

  13. Physical and chemical characteristics of pitaya fruits at physiological maturity.

    PubMed

    Ortiz, T A; Takahashi, L S A

    2015-01-01

    The aim of this study was to analyze the physical and chemical characteristics of the maturation process of pitaya fruit (Hylocereus undatus) to identify indicators that can be used to determine the point of physiological maturity and establish the optimal timing of physiological maturity for harvesting the fruit. A completely randomized experimental design was employed and four biological repeats were performed. Physiological maturity was assessed using various physical characteristics: longitudinal length (LL), equatorial diameter (ED), pericarp thickness (PeT), pulp thickness (PuT), fruit mass (FM), pulp mass (PuM), pericarp mass (PeM), pericarp percentage (%Pe), pulp percentage (%Pu), pulp/pericarp ratio (Pu/Pe), pericarp color index (CI), hue color angle (h°), lightness index (L*), chroma (C*), blue-yellow variation (b*), and green-red variation (a*). Additionally, chemical characteristics such as soluble solid content (SS), titratable acidity (TA), SS/TA ratio, and pH were screened. The data were statistically analyzed by fitting regression models and computing Pearson's correlation coefficients (P < 0.05). Physiological maturity in pitaya fruits occurred between the 30th and 32nd days after anthesis, and this proved to be the optimal period for harvest. At this time, the fruit was completely red with high SS, and had the recommended values of TA, pH, and SS/TA ratio. During this period, ED, PuT, FM, PuM, %Pu, and Pu/Pe increased while PeT, PeM, and %Pe fell; these changes are considered desirable by producers and/or consumers. PuM was the variable that displayed more strong's association with other variables in the analysis. PMID:26600501

  14. Genetics of water use physiology in locally adapted Arabidopsis thaliana.

    PubMed

    Mojica, Julius P; Mullen, Jack; Lovell, John T; Monroe, J Grey; Paul, John R; Oakley, Christopher G; McKay, John K

    2016-10-01

    Identifying the genetic basis of adaptation to climate has long been a goal in evolutionary biology and has applications in agriculture. Adaptation to drought represents one important aspect of local adaptation, and drought is the major factor limiting agricultural yield. We examined local adaptation between Sweden and Italy Arabidopsis thaliana ecotypes, which show contrasting levels of water availability in their local environments. To identify quantitative trait loci (QTL) controlling water use physiology traits and adaptive trait QTL (genomic regions where trait QTL and fitness QTL colocalize), we performed QTL mapping on 374F9 recombinant inbred lines in well-watered and terminal drought conditions. We found 72 QTL (32 in well-watered, 31 in drought, 9 for plasticity) across five water use physiology traits: δ(13)C, rosette area, dry rosette weight, leaf water content and percent leaf nitrogen. Some of these genomic regions colocalize with fitness QTL and with other physiology QTL in defined hotspots. In addition, we found evidence of both constitutive and inducible water use physiology QTL. Finally, we identified highly divergent candidate genes, in silico. Our results suggest that many genes with minor effects may influence adaptation through water use physiology and that pleiotropic water use physiology QTL have fitness consequences. PMID:27593459

  15. Effects of Deployment on Musculoskeletal and Physiological Characteristics and Balance.

    PubMed

    Nagai, Takashi; Abt, John P; Sell, Timothy C; Keenan, Karen A; McGrail, Mark A; Smalley, Brian W; Lephart, Scott M

    2016-09-01

    Despite many nonbattle injuries reported during deployment, few studies have been conducted to evaluate the effects of deployment on musculoskeletal and physiological characteristics and balance. A total of 35 active duty U.S. Army Soldiers participated in laboratory testing before and after deployment to Afghanistan. The following measures were obtained for each Soldier: shoulder, trunk, hip, knee, and ankle strength and range of motion (ROM), balance, body composition, aerobic capacity, and anaerobic power/capacity. Additionally, Soldiers were asked about their physical activity and load carriage. Paired t tests or Wilcoxon tests with an α = 0.05 set a priori were used for statistical analyses. Shoulder external rotation ROM, torso rotation ROM, ankle dorsiflexion ROM, torso rotation strength, and anaerobic power significantly increased following deployment (p < 0.05). Shoulder extension ROM, shoulder external rotation strength, and eyes-closed balance (p < 0.05) were significantly worse following deployment. The majority of Soldiers (85%) engaged in physical activity. In addition, 58% of Soldiers reported regularly carrying a load (22 kg average). The deployment-related changes in musculoskeletal and physiological characteristics and balance as well as physical activity and load carriage during deployment may assist with proper preparation with the intent to optimize tactical readiness and mitigate injury risk. PMID:27612352

  16. The Clinical Physiology of Water Metabolism

    PubMed Central

    Weitzman, Richard E.; Kleeman, Charles R.

    1979-01-01

    The renal reabsorption of water independent of solute is the result of the coordinated function of the collecting duct and the ascending limb of the loop of Henle. The unique juxtaposition of the ascending and descending portions of the loop of Henle and of the vasa recta permits the function of a counter-current multiplier system in which water is removed from the tubular lumen and reabsorbed into the circulation. The driving force for reabsorption is the osmotic gradient in the renal medulla which is dependent, in part, on chloride (followed by sodium) pumping from the thick ascending loop of Henle. Urea trapping is also thought to play an important role in the generation of a hypertonic medullary interstitium. Arginine vasopressin (AVP) acts by binding to receptors on the cell membrane and activating adenylate cyclase. This, inturn, results in the intracellular accumulation of cyclic adenosine monophosphate (AMP) which in some fashion abruptly increases the water permeability of the luminal membrane of cells in the collecting duct. As a consequence, water flows along an osmotic gradient out of the tubular lumen into the medullary interstitium. Diabetes insipidus is the clinical condition associated with either a deficiency of or a resistance to AVP. Central diabetes insipidus is due to diminished release of AVP following damage to either the neurosecretory nuclei or the pituitary stalk. Possible causes include idiopathic, familial, trauma, tumor, infection or vascular lesions. Patients present with polyuria, usually beginning over a period of a few days. The diagnosis is made by showing that urinary concentration is impaired after water restriction but that there is a good response to exogenous vasopressin therapy. Nephrogenic diabetes insipidus can be identified by a patient's lack of response to AVP. Nephrogenic diabetes insipidus is caused by a familial defect, although milder forms can be acquired as a result of various forms of renal disease. Central

  17. The Clinical Physiology of Water Metabolism

    PubMed Central

    Weitzman, Richard E.; Kleeman, Charles R.

    1980-01-01

    Hyperosmolality occurs when there are defects in the two major homeostatic mechanisms required for water balance—thirst and arginine vasopressin (AVP) release. In this situation hypotonic fluids are lost in substantial quantities causing depletion of both intracellular and extracellular fluid compartments. Patients with essential hypernatremia have defective osmotically stimulated AVP release and thirst but may have intact mechanisms for AVP release following hypovolemia. Hyperosmolality can also be seen in circumstances in which impermeable solutes are present in excessive quantities in extracellular fluid. Under these conditions there is cellular dehydration and the serum sodium may actually be reduced by water drawn out of cells along an osmotic gradient. Hyposmolality and hyponatremia may be seen in a variety of clinical conditions. Salt depletion, states in which edema occurs and the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) may all produce severe dilution of body fluids resulting in serious neurologic disturbances. The differential diagnosis of these states is greatly facilitated by careful clinical assessment of extracellular fluid volume and by determination of urine sodium concentration. Treatment of the hyposmolar syndromes is contingent on the pathophysiology of the underlying disorder; hyponatremia due to salt depletion is treated with infusions of isotonic saline whereas mild hyponatremia in cirrhosis and ascites is best treated with water restriction. Severe symptomatic hyponatremia due to SIADH is treated with hypertonic saline therapy, sometimes in association with intravenous administration of furosemide. Less severe, chronic cases may be treated with dichlormethyltetracycline which blocks the action of AVP on the collecting duct. ImagesFigure 43.Figure 44.Figure 47. PMID:6246683

  18. Body composition and physiological characteristics of law enforcement officers.

    PubMed Central

    Spitler, D L; Jones, G; Hawkins, J; Dudka, L

    1987-01-01

    The physical work capacity, body composition, and physiological characteristics of 12 law enforcement officers (9 males, 3 females) were measured. Subjects included a representative sample from the occupational categories of detective, staff, investigative and patrol officer. Mean maximal oxygen uptake of the men was 42.1 +/- 8.9 ml.kg-1min-1 with mean values of 41.5 +/- 8.7 ml.kg-1min-1 for the women. Measurement of body composition indicated an average of 24.4 +/- 7.1% body fat for the men and 30.9 +/- 1.2% for the women. Muscular power, strength, and endurance as measured by isolated limb flexion-extension movement and fitness test performance was considered average with no excessive bilateral differences. The results of this study were compared with other investigations of law enforcement officers of similar age groups. The officers displayed average or above health and physical fitness scores for their age classification and were able to complete all police task-oriented tests. PMID:3435817

  19. Physiological noise compensation in gradient-echo myelin water imaging.

    PubMed

    Nam, Yoonho; Kim, Dong-Hyun; Lee, Jongho

    2015-10-15

    In MRI, physiological noise which originates from cardiac and respiratory functions can induce substantial errors in detecting small signals in the brain. In this work, we explored the effects of the physiological noise and their compensation methods in gradient-echo myelin water imaging (GRE-MWI). To reduce the cardiac function induced inflow noise, flow saturation RF pulses were applied to the inferior portion of the head, saturating inflow blood signals. For the respiratory function induced B0 fluctuation compensation, a navigator echo was acquired, and respiration induced phase errors were corrected during reconstruction. After the compensations, the resulting myelin water images show substantially improved image quality and reproducibility. These improvements confirm the importance and usefulness of the physiological noise compensations in GRE-MWI. PMID:26172308

  20. Physiological Effects of Trace Elements and Chemicals in Water

    ERIC Educational Resources Information Center

    Varma, M. M.; And Others

    1976-01-01

    The physiological effects on humans and animals of trace amounts of organic and unorganic pollutants in natural and waste waters are examined. The sensitivity of particular organs and species is emphasized. Substances reviewed include mercury, arsenic, cadmium, lead, chromium, fluorides, nitrates and organics, including polychlounated biphenyls.…

  1. SYMPOSIUM IN ITALY: FISH PHYSIOLOGY, TOXICOLOGY, AND WATER QUALITY

    EPA Science Inventory

    Scientists from Europe, North America and South America convened in Capri, Italy, April 24-28, 2006 for the Ninth International Symposium on Fish Physiology, Toxicology, and Water Quality. The subject of the meeting was Eutrophication: The toxic effects of ammonia, nitrite and th...

  2. The Characteristic Curves of Water

    NASA Astrophysics Data System (ADS)

    Neumaier, Arnold; Deiters, Ulrich K.

    2016-09-01

    In 1960, E. H. Brown defined a set of characteristic curves (also known as ideal curves) of pure fluids, along which some thermodynamic properties match those of an ideal gas. These curves are used for testing the extrapolation behaviour of equations of state. This work is revisited, and an elegant representation of the first-order characteristic curves as level curves of a master function is proposed. It is shown that Brown's postulate—that these curves are unique and dome-shaped in a double-logarithmic p, T representation—may fail for fluids exhibiting a density anomaly. A careful study of the Amagat curve (Joule inversion curve) generated from the IAPWS-95 reference equation of state for water reveals the existence of an additional branch.

  3. [Effect of red and blue spectrum on photosynthesis physiological characteristics of two ecotypes of Leymus chinensis].

    PubMed

    Zhou, Chan; Yang, Yun-Fei; Wang, Kun

    2008-07-01

    Photosynthesis physiological characteristics of two ecotypes of Leymus chinensis were studied under different red and blue light excitation by LED red and blue lamp-house. Photosynthesis did not carry on under red and blue light of 50 micromol x m(-2) x s(-1). When red and blue light intensity was increased, photosynthesis rate, stoma limit value and transpiration rate of the two ecotypes of Leymus chinensis were all increased. But photosynthesis rate stopped increasing under red and blue light of 1 150 micromol x m(-2) x s(-1) for grey-green ecotype Leymus chinensis and of 907 micromol x m(-2) x s(-1) for yellow-green ecotype Leymus chinensis, which is known as light saturation. And the effect of blue light on photosynthesis became weaker than red light under higher light intensity. Increasing light intensity can promote plant photosynthesis rate in the range of low light intensity. But when light intensity reaches light saturation, photosynthesis rate does not increases but decreases. Because though light quantum numbers is increasing, the numbers of coloring mater does not change and is saturated. On the other hand, when the light intensity is of light saturation, the stoma limit value was increased and the transpiration rate was decreased in order to reduce water waste. When light intensity reaches the value that plant can bear, the plant will automatically close stoma in order to decrease transpiration and to save water. Plant balances every physiological index and makes sure that physiology damage is the least and production is the greatest. Although grey-green ecotype Leymus chinensis has lower stoma limit and higher water waste, it also has higher photosynthesis rate than yellow-green ecotype Leymus chinensis. And the photosynthesis capability and physiology adaptation of grey-green ecotype Leymus chinensis is greater than that of yellow-green ecotype Leymus chinensis. PMID:18844135

  4. Zinc deficiency affects physiological and anatomical characteristics in maize leaves.

    PubMed

    Mattiello, Edson M; Ruiz, Hugo A; Neves, Julio C L; Ventrella, Marília C; Araújo, Wagner L

    2015-07-01

    Zinc (Zn) is an essential microelement involved in several plant physiological processes. Therefore, it is important to identify Zn deficiencies promptly--before extensive damage occurs to the plant. The diagnostic tools that are used to identify Zn deficiencies are very important in areas where Zn deficiencies occur. Such diagnostic tools are vital for nutritional management and fertilizer recommendations. The current study investigated the effects of Zn deficiency on maize plants by recording a number of physiological and anatomical parameters. A Zn omission trial (from 0 to 22 days) was carried out to produce plants that had varying degrees of Zn deficiency. Typical symptoms of Zn deficiency (e.g. chlorotic stripes and purple shades on the edges and leaf sheath) appeared 16 days after the omission of Zn from nutrient solutions. As the time of Zn omission increased, there were significant decreases in net photosynthesis, stomatal conductance, maximal efficiency of photosystem I (evaluated by Fv/Fm), biomass (dry weight) and Zn concentrations in plants. Zinc-deficient plants also had a lower vascular bundle proportion coupled with a higher stomata density. These physiological and anatomical changes negatively impacted plant growth. Moreover, they occurred before visible symptoms of Zn deficiency were observed. Zinc concentrations were recorded for younger leaves, rather than for more mature leaves, which is usually recommended for plant analysis. The results demonstrate that the analysis of Zn in young leaves of maize is a very sensitive indicator of Zn status. PMID:26135475

  5. Differential responses of grapevine rootstocks to water stress are associated with adjustments in fine root hydraulic physiology and suberization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water deficits are known to alter fine root structure and function, but little is known about how these responses contribute to differences in drought resistance across grapevine rootstocks. We studied how water deficit affects root anatomical and physiological characteristics in two grapevine root...

  6. [Effects of flooding on the photosynthetic physiology characteristics of Pterocarya stenoptera seedlings].

    PubMed

    Wang, Chao-Ying; Li, Chang-Xiao; Zhang, Ye

    2013-03-01

    Three water treatments (control, CK; continuous flooding, CF; and periodic flooding, PF) were installed to simulate the soil moisture change of the riparian zone in the Three Gorges Reservoir (TGR) region of China to study the physiological and ecological adaptation mechanisms of the native plant species Pterocarya stenoptera seedlings to the soil moisture change. All the water treatments had significant effects on the photosynthesis, biomass accumulation, and growth of the P. stenoptera seedlings. As compared with those in CK, the seedling's net photosynthetic rate (Pn) and stomatal conductance (gs) in treatments CF and PF were significantly lower while the intercellular carbon dioxide concentration was significantly higher, and the Pn and gs in CF and PF declined initially followed by a gradual recovery or tended to be stable. With the extension of treatment time, the total biomass and root-, stem-, and leaf biomass, plant height, and basal diameter in CF and PF all presented an increasing trend. Throughout the experimental period, the total biomass, root- and leaf biomass, and plant height in CF and PF and the stem biomass in PF were significantly lower than those in CK, whereas the stem biomass in CF had no significant difference with that in CK, though the basal diameter in CF was significantly higher than that in CK. It was suggested that the P. stenoptera seedlings had the physiological and ecological characteristics of tolerating flooding rather than flooding-drought alteration. PMID:23755480

  7. Stable isotopes in leaf water and transpiration - tools to assess leaf physiology and water uptake

    NASA Astrophysics Data System (ADS)

    Gessler, Arthur; Roddy, Adam; Volkmann, Till; Haberer, Kristine

    2014-05-01

    New laser based isotope technology allows online determination of the isotopic composition of water transpired from leaves. With this tool we can get new insights into leaf water physiology during day-night-cycles but also track the dynamics of plant water uptake with high temporal resolution. This talk we will give an overview on the following emerging topics - Leaf level physiology: The isotopic non-steady state of leaf water during the diel course - Plant-soil-atmosphere coupling: Dynamics of water uptake by plants Brought together both topics allow to get deeper insights into the effects of environmental parameters on the water balance of ecosystems bridging temporal and spatial scales. The findings from this research might help integrating plant physiological information, soil hydrological processes and the interaction between plant and soil processes in hydrological models.

  8. Physiological characteristics of mercury uptake by two estuarine species

    USGS Publications Warehouse

    Luoma, S.N.

    1977-01-01

    Rapid uptake and slow loss of Hg will result from short exposures of some organisms to this metal, due to the transformation of Hg to a slowly exchanging form within the organisms. The extent of the difference between exposure time and depuration time will depend upon the rate of transformation during uptake. For the polychaete worm Neanthes succinea and the shrimp Palaemon debilis such transformations are extremely rapid. The exchange of Hg from the slowly exchanging compartment is similar among a wide variety of species. Thus, interspecies differences in susceptibility to Hg may be determined by differences in biochemical transformation rates and physiological permeability to the metal. ?? 1977 Springer-Verlag.

  9. Physiology

    ERIC Educational Resources Information Center

    Kay, Ian

    2008-01-01

    Underlying recent developments in health care and new treatments for disease are advances in basic medical sciences. This edition of "Webwatch" focuses on sites dealing with basic medical sciences, with particular attention given to physiology. There is a vast amount of information on the web related to physiology. The sites that are included here…

  10. Physiological and acoustic characteristics of the male music theatre voice.

    PubMed

    Bourne, Tracy; Garnier, Maëva; Samson, Adeline

    2016-07-01

    Six male music theatre singers were recorded in three different voice qualities: legit and two types of belt ("chesty" and "twangy"), on two vowels ([e] and [ɔ]), at four increasing pitches in the upper limit of each singer's belt range (∼250-440 Hz). The audio signal, the electroglottographic (EGG) signal, and the vocal tract impedance were all measured simultaneously. Voice samples were analyzed and then evaluated perceptually by 16 expert listeners. The three qualities were produced with significant differences at the physiological, acoustical, and perceptual levels: Singers produced belt qualities with a higher EGG contact quotient (CQEGG) and greater contacting speed quotient (Qcs), greater sound pressure level (SPL), and energy above 1 kHz (alpha ratio), and with higher frequencies of the first two vocal tract resonances (fR1, fR2), especially in the upper pitch range when compared to legit. Singers produced the chesty belt quality with higher CQEGG, Qcs, and SPL values and lower alpha ratios over the whole belt range, and with higher fR1 at the higher pitch range when compared to twangy belt. Consistent tuning of fR1 to the second voice harmonic (2f0) was observed in all three qualities and for both vowels. Expert listeners tended to identify all qualities based on the same acoustical and physiological variations as those observed in the singers' intended qualities. PMID:27475183

  11. Physiological responses of Chinese longsnout catfish to water temperature

    NASA Astrophysics Data System (ADS)

    Han, Dong; Xie, Shouqi; Zhu, Xiaoming; Yang, Yunxia

    2011-05-01

    We evaluated the effect of water temperature on the growth and physiology of the Chinese longsnout catfish ( Leiocassis longirostris Günther). The fish were reared at four temperatures (20, 25, 30, and 35°C) and sampled on days 7, 20, and 30. We measured plasma levels of insulin, free thyroxine (FT4), free 3,5,3'-triiodothyronine (FT3), lysozyme and leukocyte phagocytic activity. The optimum water temperature for growth was 27.7°C. The plasma levels of insulin and FT4 declined significantly ( P<0.05) on day 30 at temperatures above 20°C. Lysozyme activity was significantly ( P<0.05) lower at 25°C than at other temperatures. We conclude that final weight, insulin, FT4, and lysozyme were significantly affected by water temperature.

  12. Relationship between anthropometric and physiological characteristics in youth soccer players.

    PubMed

    Wong, Pui-Lam; Chamari, Karim; Dellal, Alexandre; Wisløff, Ulrik

    2009-07-01

    This study examined the relationship between anthropometric and physiological performances among youth soccer players and the positional differences for these variables. Seventy U14 male soccer players (goalkeeper: 10, defender: 20, midfielder: 25, and forward: 15) participated in this study. Body mass was significantly (p < 0.05) correlated with ball shooting speed (r = 0.58) and 30 m sprint time (r = -0.54). Body height was significantly (p < 0.05) correlated with vertical jump height (r = 0.36), 10 m (r = -0.32) and 30 m (r = -0.64) sprint times, Yo-Yo intermittent endurance run (YYIER) distance (r = 0.26), and running time during maximal oxygen uptake (Vo2max) (r = 0.35). Body mass index (BMI) was significantly (p < 0.05) correlated with ball shooting speed (r = 0.31), 30 m sprint time (r = -0.24), Hoff test dribble distance (r = -0.29), YYIER distance (r = -0.25), submaximal running cost (r = -0.38), Vo2max (r = -0.42), and the corresponding running time (r = -0.24). Significant positional differences were observed in anthropometry (body mass [p < 0.01], height [p < 0.01], and BMI [p < 0.01]) but not in physiological performances. This study provides a scientific rationale behind the coaches' practice of selecting young soccer players according to their anthropometry for short-term benefits such as heavier players for higher ball shooting speed and 30-m sprint ability as an example. However, this does not justify such practice in the long-term process of player development. PMID:19528844

  13. Apparent water permeability as a physiological parameter in crustaceans

    PubMed

    Rasmussen; Andersen

    1996-01-01

    This article reviews the use of apparent water permeability (AWP) calculated from measurements of isotope-labelled water flux as a physiological estimate of whole-body water permeability in aquatic invertebrates. The rationale and practices of AWP calculations are described in an Appendix. AWP calculations have provided a wealth of information. However, the validity of the method and therefore also of the information obtained have been questioned. Consequently, the use of AWP data in discussions of osmotic and fluid homeostatic questions in aquatic invertebrates is limited. This article reviews three decades of published experiments in which measurements of isotope-labelled water fluxes were used to estimate water permeability in aquatic invertebrates. Data on 24 species of arthropod, most of them decapod crustaceans, are presented. The combined data indicate that the results obtained by different investigators on the same species show good agreement, even though different tracers and experimental methods have been applied. When available, results from other kinds of studies were used to evaluate the results obtained using the AWP measurements. The various results demonstrate that AWP is influenced not only by natural environmental factors, such as salinity and temperature, and by anthropogenic factors, such as potentially toxic trace metals, but that it is also regulated by intrinsic factors, such as ecdysis and life cycle stage. The results obtained can often be explained as effects of components of the habitat of the animal. Accordingly, studies on variations in AWP contribute to our understanding of the different physiological strategies used by species living in a changing environment. We conclude that calculations of AWP offer reliable, relevant physiological data in a range of crustacean species, as long as methodological limitations and uncertainties are kept in mind. In addition, we propose some possible new ways of applying AWP calculations to marine

  14. Physiological characteristics and performance of top U.S. biathletes.

    PubMed

    Rundell, K W; Bacharach, D W

    1995-09-01

    Success in biathlon involves skiing fast and shooting accurately. The purpose of this study was to determine whether physiological laboratory test results relate to success in biathlon. Tests included treadmill run and double-pole lactate profile and VO2peak tests, and a double-pole peak power test (UBP). 1993 National Points Rank (NR), racing ski time (ST), and shooting percentage (SP) from 1993 World Team Trials and laboratory test results (1993; N = 11 males, 10 females) were examined. Of athletes tested, six males and six females were top 10 U.S. ranked. Significance was identified between NR and ST (males, r = -0.88; females, r = -0.91). NR and SP were related for females (r = 0.75). Maximum run time during the VO2peak test was the only parameter related to NR (r = 0.72) or ST (r = -0.80) for males. Significance was identified for an uphill 1 km on snow double-pole time trial to NR (r = -0.84) and SP (r = -0.79) (subgroup; N = 8 males). For females, NR was related to running VO2peak (r = 0.81) and UBP (r = 0.95). Double-pole and running VO2peak were related to SP for women. This study suggests that SP is more important to NR for females than for males, and gender-specific tests might better predict success in elite biathlon skiers. PMID:8531629

  15. Physiological characteristics of elite dancers of different dance styles.

    PubMed

    Liiv, Helena; Jürimäe, Toivo; Mäestu, Jarek; Purge, Priit; Hannus, Aave; Jürimäe, Jaak

    2014-01-01

    The present investigation was aimed to study international level dancesport dancer's aerobic capacity during incremental test and competition simulation in relation to the gender, dance style and international ranking. A total of 30 couples (12 Standard, 7 Latin American and 11 Ten Dance; aged 22.8 ± 6.6 years male and 22.0 ± 6.4 years female) performed an incremental treadmill test and competition simulation. In this study for the first time we carried out longer than one round competition simulation and compared three different dancesport styles (Standard, Latin American and Ten Dance). The results showed that dancers of these three dance styles had similar aerobic capacity values. The average maximal oxygen consumption (VO2max) values were 59.6 ± 5.1 and 51.2 ± 6.2 ml · min(-1) · kg(-1) for male and female dancers, respectively. Competition simulation showed that Latin American Dance discipline is physiologically more intensive compared to Standard and Ten Dance styles especially for the female dancers. It appeared that male and female Standard dancers tended to perform at lower intensity than anaerobic threshold (AT) during competition simulation (male 97.3 ± 2.9%; female 97.9 ± 3.6%), while Latin (male 101.4 ± 2.9%; female 106.7 ± 5.9%) and Ten Dance (male 100.7 ± 6.4%; female 99.2 ± 5.6%) competition intensity was higher compared to AT level of athletes. The highest heart rate during competition simulation was always found during the last dances (Paso Double, Jive or Quickstep) and in the last round of each dance style. No significant relationship between VO2max values and international rankings was registered. PMID:24444238

  16. Morphological and physiological characteristics of dermal photoreceptors in Lymnaea stagnalis

    PubMed Central

    Takigami, Satoshi; Sunada, Hiroshi; Horikoshi, Tetsuro; Sakakibara, Manabu

    2014-01-01

    Dermal photoreceptors located in the mantle of Lymnaea stagnalis were histologically and physiologically characterized. Our previous study demonstrated that the shadow response from dermal photoreceptors induces the whole-body withdrawal response. Through the interneuron, RPeD11, we detected that the light-off response indirectly originated from a dermal photoreceptor. Previous observations, based on behavioral pharmacology, revealed that cyclic guanosine monophosphate acts as a second messenger in the dermal photoreceptor. Furthermore, gastropods possess dermal photoreceptors containing rhodopsin, as a photopigment, and another photo-sensitive protein, arrestin, responsible for terminating the light response. Thus, we chose three antibodies, anti-cGMP, anti-rhodopsin, and anti-β-arrestin, to identify the dermal photoreceptor molecules in Lymnaea mantle. Extracellular recording, using a suction electrode on the mantle, revealed a light off-response from the right parietal nerve. Overlapping structures, positive against each of the antibodies, were also observed. Numerous round, granular particles of 3–47 μm in diameter with one nucleus were distributed around pneumostome and/or inside the mantle. The cells surrounding the pneumostome area, located 10 μm beneath the surface, tended to have smaller cell soma ranging from 3 to 25 μm in diameter, while cells located in other areas were distributed uniformly inside the mantle, with a larger diameter ranging from 12 to 47 μm. The histological examination using back-filing Lucifer Yellow staining of the right parietal nerve with the three dermal photoreceptor antibodies confirmed that these overlapping-stained structures were dermal photoreceptors in Lymnaea. PMID:27493502

  17. Cyclic AMP phosphodiesterase in Salmonella typhimurium: characteristics and physiological function.

    PubMed

    Botsford, J L

    1984-11-01

    The physiological function of cyclic AMP (cAMP) phosphodiesterase in Salmonella typhimurium was investigated with strains which were isogenic except for the cpd locus. In crude broken-cell extracts the properties of the enzyme were found to be similar to those reported for Escherichia coli. The specific activity in the mutant was less than 1% that in the wild type. Rates of cAMP production in the mutant were as much as twice those observed in the wild type. The amount of cAMP accumulated when cells grew overnight with limiting glucose was 4.5-fold greater in the mutant than in the wild type. The intracellular concentration of cAMP in the two strains was measured directly, using four different techniques to wash the cells to remove extracellular cAMP. The cAMP level in the cpd strain was only 25% greater than in the wild type. The functional concentration of the cAMP receptor protein-cAMP complex was estimated indirectly from the specific activity of beta-galactosidase in the two strains after introducing F'lac. When cells were grown with carbon sources permitting synthesis of different levels of cAMP, the specific activity of the enzyme was at most 25% greater in the cpd strain. The cpd strain was more sensitive to the effects of exogenous cAMP. Exogenous cAMP relieved both permanent and transient catabolite repression of the lac operon at lower concentrations in the cpd strain than in the wild type. When cells grew with glucose, glycerol, or ribose, exogenous cAMP inhibited growth of the mutant strain more than the wild type. PMID:6094495

  18. Renal water reabsorption: a physiologic retrospective in a molecular era.

    PubMed

    Schafer, James A

    2004-10-01

    The cloning and sequencing of the aquaporin water channels has been an enormous advance in the biomedical sciences, as recognized by the award of the Nobel Prize to Peter Agre last year. Among many other examples, expression of aquaporin proteins in Xenopus oocytes and other heterologous expression systems has confirmed two important models of renal function: the increase in the water permeability of the collecting duct by antidiuretic hormone (ADH), and the mechanism of near isosmotic volume reabsorption by the proximal tubule. These mechanisms were the subjects of intensive investigation by numerous investigators, including Thomas E. Andreoli, who is being honored by this symposium, and who developed many of the key concepts in these areas. His early work with artificial lipid bilayer membranes and the pore-forming antibiotic amphotericin provided the rigorous foundation in experimental and conceptual modeling techniques that he later applied to physiologic and pathophysiologic mechanisms in the kidney, which are summarized in this retrospective. Dr. Andreoli and his colleagues proposed a water channel mechanism for the action of ADH, which has been confirmed by the cloning and heterologous expression of aquaporin-2. They also proposed that volume reabsorption by the proximal tubule depended on a very high hydraulic conductivity and the development of luminal hypotonicity produced by active solute reabsorption. This model has also been confirmed in mice in which aquaporin-1 expression is knocked out, resulting in a low proximal tubule water permeability that exaggerates the development of luminal hypotonicity. PMID:15461698

  19. Water consumption and water-saving characteristics of a ground cover rice production system

    NASA Astrophysics Data System (ADS)

    Jin, Xinxin; Zuo, Qiang; Ma, Wenwen; Li, Sen; Shi, Jianchu; Tao, Yueyue; Zhang, Yanan; Liu, Yang; Liu, Xiaofei; Lin, Shan; Ben-Gal, Alon

    2016-09-01

    The ground cover rice production system (GCRPS) offers a potentially water-saving alternative to the traditional paddy rice production system (TPRPS) by furrow irrigating mulched soil beds and maintaining soils under predominately unsaturated conditions. The guiding hypothesis of this study was that a GCRPS would decrease both physiological and non-physiological water consumption of rice compared to a TPRPS while either maintaining or enhancing production. This was tested in a two-year field experiment with three treatments (TPRPS, GCRPSsat keeping root zone average soil water content near saturated, and GCRPS80% keeping root zone average soil water content as 80-100% of field water capacity) and a greenhouse experiment with four treatments (TPRPS, GCRPSsat, GCRPSfwc keeping root zone average soil water content close to field water capacity, and GCRPS80%). The water-saving characteristics of GCRPS were analyzed as a function of the measured soil water conditions, plant parameters regarding growth and production, and water input and consumption. In the field experiment, significant reduction in both physiological and non-physiological water consumption under GCRPS lead to savings in irrigation water of ∼61-84% and reduction in total input water of ∼35-47%. Compared to TPRPS, deep drainage was reduced ∼72-88%, evaporation was lessened ∼83-89% and transpiration was limited ∼6-10% under GCRPS. In addition to saving water, plant growth and grain yield were enhanced under GCRPS due to increased soil temperature in the root zone. Therefore, water use efficiencies (WUEs), based on transpiration, irrigation and total input water, were respectively improved as much as 27%, 609% and 110% under GCRPS. Increased yield attributed to up to ∼19%, decreased deep drainage accounted for ∼75%, decreased evaporation accounted for ∼14% and reduced transpiration for ∼5% of the enhancement in WUE of input water under GCRPS, while increased runoff and water storage had

  20. Seasonal variations and aeration effects on water quality improvements and physiological responses of Nymphaea tetragona Georgi.

    PubMed

    Lu, Xiao-Ming; Lu, Peng-Zhen; Huang, Min-Sheng; Dai, Ling-Peng

    2013-01-01

    Seasonal variations and aeration effects on water quality improvements and the physiological responses of Nymphaea tetragona Georgi were investigated with mesocosm experiments. Plants were hydroponically cultivated in six purifying tanks (aerated, non-aerated) and the characteristics of the plants were measured. Water quality improvements in purifying tanks were evaluated by comparing to the control tanks. The results showed that continuous aeration affected the plant morphology and physiology. The lengths of the roots, petioles and leaf limbs in aeration conditions were shorter than in non-aeration conditions. Chlorophyll and soluble protein contents of the leaf limbs in aerated tanks decreased, while peroxidase and catalase activities of roots tissues increased. In spring and summer, effects of aeration on the plants were less than in autumn. Total nitrogen (TN) and ammonia nitrogen (NH4(+)-N) in aerated tanks were lower than in non-aerated tanks, while total phosphorus (TP) and dissolved phosphorus (DP) increased in spring and summer. In autumn, effects of aeration on the plants became more significant. TN, NH4(+)-N, TP and DP became higher in aerated tanks than in non-aerated tanks in autumn. This work provided evidences for regulating aeration techniques based on seasonal variations of the plant physiology in restoring polluted stagnant water. PMID:23819294

  1. Psychological and physiological responses during an exam and their relation to personality characteristics.

    PubMed

    Spangler, G

    1997-08-01

    The aim of the study was to compare emotional and physiological responses to real and control examinations and to assess their relation to personality characteristics. Emotional responses were assessed by state anxiety and perceived stress. The assessment of physiological responses included the activity of the cardiac system (heart periods, vagal tone), the adrenocortical system (cortisol) and the immune system (immune globulin A, sIgA). Emotional and physiological responses of 23 students (12 males, 11 females) were assessed during an oral exam at the end of a basic course in psychology which was a prerequisite for the students' final exams. For the control condition physiological responses were assessed one week before the examination during a memory test. The findings of the study demonstrate different emotional and physiological response patterns to examinations as compared to the control condition. Heightened anxiety was observed only before the exam. Whereas within-situation physiological responses (higher heart periods, cortisol, and sIgA; lower vagal tone) were observed both under the exam and control condition, responses to exam condition indicated pre-exam anticipatory activation and post-exam restricted recovery responses. With regard to personality characteristics subjects with high ego-resiliency showed more flexible adaptation than subjects with low ego-resiliency both on the emotional level (anxiety down-regulation after exam) and on the physiological level (situation-specific responses, quick recovery). Subjects with high ego-control exhibited a lower physiological reactivity under both conditions, i.e. they seemed to maintain longer their control also on a physiological level independent of the type of situation. PMID:9364621

  2. Physiological evidence that pyramidal neurons lack functional water channels.

    PubMed

    Andrew, R David; Labron, Mark W; Boehnke, Susan E; Carnduff, Lisa; Kirov, Sergei A

    2007-04-01

    The physiological conditions that swell mammalian neurons are clinically important but contentious. Distinguishing the neuronal component of brain swelling requires viewing intact neuronal cell bodies, dendrites, and axons and measuring their changing volume in real time. Cultured or dissociated neuronal somata swell within minutes under acutely overhydrated conditions and shrink when strongly dehydrated. But paradoxically, most central nervous system (CNS) neurons do not express aquaporins, the membrane channels that conduct osmotically driven water. Using 2-photon laser scanning microscopy (2PLSM), we monitored neuronal volume under osmotic stress in real time. Specifically, the volume of pyramidal neurons in cerebral cortex and axon terminals comprising cerebellar mossy fibers was measured deep within live brain slices. The expected swelling or shrinking of the gray matter was confirmed by recording altered light transmittance and by indirectly measuring extracellular resistance over a wide osmotic range of -80 to +80 milliOsmoles (mOsm). Neurons expressing green fluorescent protein were then imaged with 2PLSM between -40 and +80 mOsm over 20 min. Surprisingly, pyramidal somata, dendrites, and spines steadfastly maintained their volume, as did the cerebellar axon terminals. This precluded a need for the neurons to acutely regulate volume, preserved their intrinsic electrophysiological stability, and confirmed that these CNS nerve cells lack functional aquaporins. Thus, whereas water easily permeates the aquaporin-rich endothelia and glia driving osmotic brain swelling, neurons tenatiously maintain their volume. However, these same neurons then swell dramatically upon oxygen/glucose deprivation or [K+]0 elevation, so prolonged depolarization (as during stroke or seizure) apparently swells neurons by opening nonaquaporin channels to water. PMID:16723408

  3. Effects of potassium nutrition on physiological processes and derivative spectrum characteristics of corn plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A study was conducted to evaluate the effects of potassium nutrition on growth, development and various other physiological processes and the spectrum characteristics of corn. Corn seeds were shown in sand culture using 3.8L pots in SPAR chambers with day/night temperatures of 30/220C and Carbon Di...

  4. Root physiological and morphological characteristics of 24 rice varieties selected for diverse grain mineral

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To accumulate a mineral in the grain, a plant must first absorb that mineral from the soil. Root physiological characteristics, such as exudation of organic acids or oxygen, impact the availability, solubility and mobility of minerals in the soil, ultimately impacting the amount of minerals absorbe...

  5. Biological and physiological characteristics of Neotyphodium gansuense symbiotic with Achnatherum inebrians.

    PubMed

    Li, Chunjie; Nan, Zhibiao; Li, Fei

    2008-01-01

    Biological and physiological characteristics of Neotyphodium gansuense were compared with Neotyphodium coenophialum and Epichloë festucae at a range of temperatures and pH values, and on carbon and nitrogen amended media. N. gansuense was able to grow at 10-30 degrees C, but not at 5 degrees C, and slowly at 35 degrees C. The optimal temperature for both N. gansuense and N. coenophialum was 25 degrees C, but that of E. festucae was 20-25 degrees C. The optimal pH ranges for mycelial growth of N. gansuense, N. coenophialum and E. festucae were 5-9, 5-9 and 5-7, respectively. The Neotyphodium and Epichloë endophytes varied in their ability to grow on media containing different carbon and nitrogen nutrients. The preference of N. gansuense for carbon source was sucrose>glucose, lactose, sorbitol, inulin, maltose, mannitol, starch, fructose>xylose. Growth of all three endophytes tested was significantly improved by peptone, tryptone, casein, yeast extract and l-proline. Yeast extract, peptone, casein, tryptone, l-proline, potassium nitrate, ammonium oxalic acid and l-leucine significantly improved growth of N. gansuense. However, ammonium nitrite was not utilized at all by any tested endophyte. N. gansuense grew significantly better on potato dextrose agar (PDA) and oat meal agar (OMA) than on corn meal agar (CMA) and drunken-horse-grass agar (DA), and most slowly on water agar (WA) and saltwater nutrient agar (SNA). PMID:16962754

  6. [Survival in cold water. Physiological consequences of accidental immersion in cold water].

    PubMed

    Mantoni, Teit; Belhage, Bo; Pott, Frank Christian

    2006-09-18

    This survey addresses the immediate physiological reactions to immersion in cold water: cold shock response, diving reflex, cardiac arrhythmias and hypothermia. Cold shock response is the initial sympathetic reaction to immersion in cold water. The diving reflex is elicited by submersion of the face. Afferent and efferent nerves are the trigeminal and vagal nerves. Cardiac arrhythmias occur immediately after immersion. If the immersion persists, hypothermia becomes an issue. Hypothermia is delayed by habituation to immersion in cold water as well as insulating garments, subcutaneous fat and a large lean body mass. PMID:17026891

  7. Influence of Morphological Characteristics on Physical and Physiological Performances of Tunisian Elite Male Handball Players

    PubMed Central

    Moncef, Cherif; Said, Mohamed; Olfa, Najlaoui; Dagbaji, Gomri

    2012-01-01

    Purpose The purpose of this study was to describe the body structure and morphological characteristics of Tunisian elite handball players, and to determine the effect of these variables on functional and physical performance levels. Methods A sample of 42 male handball players (mean age 21.98±3.24 years; training duration 12 years) at international level was submitted to a test battery comprising morphological, physical and physiological assessments. Tests were yo-yo intermittent recovery test, squat jump test, countermovement jump test, vertical-jump test, and Repeated sprint Ability. Measures for assessment of anthropometric characteristics were age, size, weight, body mass index, body fat, fat mass and thin mass. Results Weight was negatively correlated to the squat jump and the countermovement jump performance. Age, weight, and body composition measures (fat and thin body mass) were additionally negatively related to the maximal oxygen uptake, and to the maximal velocity obtained in the Yo-Yo recovery test. No relationship was found between size, body mass index, body fat and the physical abilities considered. Concerning the effects of physical characteristics on the functional performances, we can note a positive relationship between squat jump, countermovement jump, and the yo-yo recovery test performance. No relationship was found between vertical jump, repeated sprint ability, and the physiological performances. Conclusions Study results point to the existence of strong correlation between morphological and physical characteristics with functional characteristics. In handball, it is possible to have a reliable estimate of anthropometric measurements, physical and physiological performances. PMID:22942992

  8. Meta-analysis of digital game and study characteristics eliciting physiological stress responses.

    PubMed

    van der Vijgh, Benny; Beun, Robbert-Jan; Van Rood, Maarten; Werkhoven, Peter

    2015-08-01

    Digital games have been used as stressors in a range of disciplines for decades. Nonetheless, the underlying characteristics of these stressors and the study in which the stressor was applied are generally not recognized for their moderating effect on the measured physiological stress responses. We have therefore conducted a meta-analysis that analyzes the effects of characteristics of digital game stressors and study design on heart rate, systolic and diastolic blood pressure, in studies carried out from 1976 to 2012. In order to assess the differing quality between study designs, a new scale is developed and presented, coined reliability of effect size. The results show specific and consistent moderating functions of both game and study characteristics, on average accounting for around 43%, and in certain cases up to 57% of the variance found in physiological stress responses. Possible cognitive and physiological processes underlying these moderating functions are discussed, and a new model integrating these processes with the moderating functions is presented. These findings indicate that a digital game stressor does not act as a stressor by virtue of being a game, but rather derives its stressor function from its characteristics and the methodology in which it is used. This finding, together with the size of the associated moderations, indicates the need for a standardization of digital game stressors. PMID:25950613

  9. Water stress and recovery in the performance of two Eucalyptus globulus clones: physiological and biochemical profiles.

    PubMed

    Correia, Barbara; Pintó-Marijuan, Marta; Neves, Lucinda; Brossa, Ricard; Dias, Maria Celeste; Costa, Armando; Castro, Bruno B; Araújo, Clara; Santos, Conceição; Chaves, Maria Manuela; Pinto, Glória

    2014-04-01

    Eucalyptus plantations are among the most productive forest stands in Portugal and Spain, being mostly used for pulp production and, more recently, as an energy crop. However, the region's Mediterranean climate, with characteristic severe summer drought, negatively affects eucalypt growth and increases mortality. Although the physiological response to water shortage is well characterized for this species, evidence about the plants' recovery ability remains scarce. In order to assess the physiological and biochemical response of Eucalyptus globulus during the recovery phase, two genotypes (AL-18 and AL-10) were submitted to a 3-week water stress period at two different intensities (18 and 25% of field capacity), followed by 1 week of rewatering. Recovery was assessed 1 day and 1 week after rehydration. Drought reduced height, biomass, water potential, NPQ and gas exchange in both genotypes. Contrarily, the levels of pigments, chlorophyll fluorescence parameters (F(v) /F(m) and (φPSII)), MDA and ABA increased. During recovery, the physiological and biochemical profile of stressed plants showed a similar trend: they experienced reversion of altered traits (MDA, ABA, E, g(s), pigments), while other parameters did not recover ((φPSII), NPQ). Furthermore, an overcompensation of CO(2) assimilation was achieved 1 week after rehydration, which was accompanied by greater growth and re-establishment of oxidative balance. Both genotypes were tolerant to the tested conditions, although clonal differences were found. AL-10 was more productive and showed a more rapid and dynamic response to rehydration (namely in carotenoid content, (φPSII) and NPQ) compared to clone AL-18. PMID:24117924

  10. Eco-physiological characteristics of Pistia stratiotes and its removal of pollutants from livestock wastewater.

    PubMed

    Chen, Jinfa; Nie, Qishan; Zhang, Yun; Hu, Jinzhao; Qing, Lin

    2014-01-01

    The effectiveness of water lettuce in removing pollutants including organic pollutants, nitrogen (NH3-N) and total phosphorus (TP) from livestock wastewater along with the physiological effects and their correlations, was studied for the first time. The results showed that the water lettuce had higher removal efficiency with low concentrations of livestock wastewater. The removal efficiency of water lettuce for different initial concentrations of livestock wastewater within 8 d was as follows: chemical oxygen demand (CODcr) (68-82%) > NH3-N (57-69%) >TP (27-45%). The speed of purification of water lettuce for CODcr, NH3-N and TP conformed to first order kinetics equations. The water quality indices CODcr, NH3-N and TP had a higher linear correlation with peroxidase (POD) activity (R(2) > 0.9(2)) than with superoxide dismutase (SOD) and catalase (CAT) activity, which indicates that the main reacting enzyme of water lettuce under high CODcr stress is peroxidase. PMID:24960015

  11. Linkage of within vineyard soil properties, grapevine physiology, grape composition and sensory characteristics in a premium wine grape vineyard.

    NASA Astrophysics Data System (ADS)

    Smart, David; Hess, Sallie; Ebeler, Susan; Heymann, Hildegarde; Plant, Richard

    2014-05-01

    Analysis of numerous vineyards has revealed a very high degree of variation exists at the within vineyard scale and may outweigh in some cases broader mesoclimatic and geological factors. For this reason, selective harvest of high quality wine grapes is often conducted and based on subjective field sensory analysis (taste). This is an established practice in many wine growing regions. But the relationships between these subjective judgments to principle soil and grapevine physiological characteristics are not well understood. To move toward greater understanding of the physiological factors related to field sensory evaluation, physiological data was collected over the 2007 and 2008 growing seasons in a selectively harvested premium production Napa Valley estate vineyard, with a history of selective harvesting based on field sensory evaluation. Data vines were established and remained as individual study units throughout the data gathering and analysis phase, and geographic information systems science (GIS) was used to geographically scale physiological and other data at the vineyard level. Areas yielding grapes with perceived higher quality (subjective analysis) were characterized by vines with 1) statistically significantly lower (P < 0.05) leaf water potential (LWP) both pre-dawn (PD) and midday (MD), 2) smaller berry diameter and weight, 3) lower pruning weights, and 4) higher soluble solids (Brix). Strong positive correlations emerged between June ψPD and pre-harvest grape berry diameter (R2 = 0.616 in 2007 and 0.413 in 2008) and similar strong correlations existed for berry weight (R2 = 0.626 in 2007 and 0.554 in 2008). A trained sensory panel performed a sensory analysis and characterized fruit using and a multivariate, principal components, analysis (PCA). This approach indicated that grapes from vines with lowest midday leaf water potential at veraison (< -1.5 MPa) had sweeter and softer pulp, absence of vegetal characteristics, and browner and crunchier

  12. Comparison of the physiological characteristics of transgenic insect-resistant cotton and conventional lines

    PubMed Central

    Li, Xiaogang; Ding, Changfeng; Wang, Xingxiang; Liu, Biao

    2015-01-01

    The introduction of transgenic insect-resistant cotton into agricultural ecosystems has raised concerns regarding its ecological effects. Many studies have been conducted to compare the differences in characteristics between transgenic cotton and conventional counterparts. However, few studies have focused on the different responses of transgenic cotton to stress conditions, especially to the challenges of pathogens. The aim of this work is to determine the extent of variation in physiological characteristics between transgenic insect-resistant cotton and the conventional counterpart infected by cotton soil-borne pathogens. The results showed that the difference in genetic backgrounds is the main factor responsible for the effects on biochemical characteristics of transgenic cotton when incubating with cotton Fusarium oxysporum. However, genetic modification had a significantly greater influence on the stomatal structure of transgenic cotton than the effects of cotton genotypes. Our results highlight that the differences in genetic background and/or genetic modifications may introduce variations in physiological characteristics and should be considered to explore the potential unexpected ecological effects of transgenic cotton. PMID:25737015

  13. Physiological, Behavioral, and Dietary Characteristics Associated with Hypertension among Kenyan Defence Forces.

    PubMed

    Mundan, Victor; Muiva, Margaret; Kimani, Samuel

    2013-01-01

    Background. Hypertensive disease is increasing in developing countries due to nutritional transition and westernization. Hypertensive disease among Kenya military may be lower because of health-focused recruitment, physical activities, routine checkups, and health awareness and management, but the disease has been increasing. Purpose. The purpose of this study was to determine physiological, behavioral, and dietary characteristics associated with hypertension among Kenyan military. Methods. A cross-sectional study involving 340 participants was conducted at Armed Forces Memorial Hospital. Participants' history, risk factors assessment, and dietary patterns were obtained by structured questionnaire, while physiological and anthropometric parameters were measured. Results. Hypertensive participants were likely to have higher age, physiological, and anthropometric measurements, and they participated in peace missions. Daily alcohol and smoking, frequent red meat, and inadequate fruits and vegetables were associated with hypertension. Conclusions. The findings mimic the main risk factors and characteristics for hypertensive disease in developed countries whose lifestyle adoption is happening fast in low and middle-income countries. Whether or not prediction rules and/or risk scores may identify at-risk individuals for preventive strategy for targeted behavioral interventions among this population require investigation. PMID:24977096

  14. Landscape and plant physiological controls on water dynamics within a watershed

    NASA Astrophysics Data System (ADS)

    Hu, J.; Looker, N. T.; Martin, J. T.; Hoylman, Z. H.; Jencso, K. G.

    2014-12-01

    Across the Western U.S., declining snowpacks have resulted in increased water limitation, leading to reduced productivity in high elevation forests. While our current understanding of how forests respond to climate change is typically focused on measuring/modeling the physiological responses and climate feedbacks, our study aims to combine physiology with hydrology to examine how landscape topography modulates the sensitivity of forests to climate. In a forested watershed in Western Montana, we linked climate variability to the physical watershed characteristics and the physiological response of vegetation to examine forest transpiration and productivity rates. Across the entire watershed, we found a strong relationship between productivity and the topographic wetness index, a proxy for soil moisture storage. However, this relationship was highly dependent on the intensity of solar radiation, suggesting that at high elevations productivity was limited by temperature, while at low elevations productivity was limited by moisture. In order to identify the mechanisms responsible for this relationship, we then examined how different coniferous species respond to changing environmental and hydrologic regimes. We first examined transpiration and productivity rates at the hillslope scale at four plots, ranging in elevation and aspect across the watershed. We found trees growing in the hollows had higher transpiration and productivity rates than trees growing in the side slope, but that these differences were more pronounced at lower elevations. We then used oxygen isotope to examine water source use by different species across the watershed. We found that trees growing in the hollows used snowmelt for a longer period. This was most likely due to upslope subsidies of snowmelt water to the hollow areas. However, we found that trees growing at lower elevations used proportionally more snowmelt than trees at the higher elevations. This was most likely due to the trees at lower

  15. Landscape and plant physiological controls on water dynamics and forest productivity within a watershed

    NASA Astrophysics Data System (ADS)

    Hu, Jia; Jencso, Kelsey; Looker, Nathaniel; Martin, Justin; Hoylman, Zachary

    2015-04-01

    Across the Western U.S., declining snowpacks have resulted in increased water limitation, leading to reduced productivity in high elevation forests. While our current understanding of how forests respond to climate change is typically focused on measuring/modeling the physiological responses and climate feedbacks, our study aims to combine physiology with hydrology to examine how landscape topography modulates the sensitivity of forests to climate. In a forested watershed in Western Montana, we linked climate variability to the physical watershed characteristics and the physiological response of vegetation to examine forest transpiration and productivity rates. Across the entire watershed, we found a strong relationship between productivity and the topographic wetness index, a proxy for soil moisture storage. However, this relationship was highly dependent on the intensity of solar radiation, suggesting that at high elevations productivity was limited by temperature, while at low elevations productivity was limited by moisture. In order to identify the mechanisms responsible for this relationship, we then examined how different coniferous species respond to changing environmental and hydrologic regimes. We first examined transpiration and productivity rates at the hillslope scale at four plots, ranging in elevation and aspect across the watershed. We found trees growing in the hollows had higher transpiration and productivity rates than trees growing in the side slope, but that these differences were more pronounced at lower elevations. We then used oxygen isotope to examine water source use by different species across the watershed. We found that trees growing in the hollows used snowmelt for a longer period. This was most likely due to upslope subsidies of snowmelt water to the hollow areas. However, we found that trees growing at lower elevations used proportionally more snowmelt than trees at the higher elevations. This was most likely due to the trees at lower

  16. [Physiological and biochemical characteristics of recalcitrant seed under the condition of true dormancy: a review].

    PubMed

    Gumilevskaia, N A; Azarkovich, M I

    2007-01-01

    The review considers and sums up the results of studies of physiological and biochemical characteristics of dormant and germinating recalcitrant seed (the object of the study, the seed of common horse chestnut, Aesculus hippocastanum L., is viewed as an exemplary case). The results of analysis of the proteomes of the axis and cotyledons have been studied and the effects of the stratification, assessed. Gene expression has been studied at the level of protein synthesis; the protein-synthesizing capacity of the cells of the embryonic axis and cotyledon storage parenchyma of mature seed and seed undergoing stratification. The extent to which the functionally active translation machinery of ripe seed depends on transcription has been assessed, and the ability to synthesize protein under the conditions of stratification has been established. It is concluded that the embryonic axis of dormant seed lacks innate dormancy and that the isolated axis exhibits diverse sensitivity to exogenous abscisic acid and other physiologically active compounds. PMID:17619586

  17. Hydrophysical correlation and water mass indication of optical physiological parameters of picophytoplankton in Prydz Bay during autumn 2008.

    PubMed

    Zhang, Fang; Ma, Yuxin; Lin, Ling; He, Jianfeng

    2012-12-01

    Flow cytometry (FCM) is efficient in detecting both abundance and optical physiological parameters including cell size and cellular carbon content-side scatter (SSC), carotenoids-green and orange fluorescence (FL1 and FL2), and red fluorescence-chlorophylls (FL3) can be obtained by FCM. The utilization of these physiological parameters in indicating water masses in Prydz Bay was investigated for the first time. Picophytoplankton were very sensitive to hydrophysical changes and present distinct characteristics of water masses: Picophytoplankton in water closer to the Amery Ice Shelf were more affected by salinity than by temperature, while temperature became more important than salinity the nearer the picophytoplankton were to the deep sea. The picophytoplankton dealt with declines in light by increasing the size of cells, which increase the fixation of carbon. This can also be increased by high temperature and salinity. Pure water masses can increase the content of chlorophylls and cellular carbon. Generally, the distributions of all the five parameters at upper water depths were less affected by temperature and salinity than by water masses; and these parameters can be as indicators to Summer Surface Water (SSW), Winter Water (WW) and Continental Shelf Water (CSW). PMID:23098920

  18. FISH PHYSIOLOGY, TOXICOLOGY AND WATER QUALITY MANAGEMENT: PROCEEDINGS OF 3RD BIENNIAL INTERNATIONAL SYMPOSIUM, NANJING, PRC

    EPA Science Inventory

    Scientists from four countries presented papers at the Third Biennial International Symposium on Fish Physiology, Toxicology and Water Quality Management, which was held on the campus of Nanjing University, Nanjing, Jiangsu Province, People's Republic of China. his proceedings in...

  19. Ubiquity, diversity and physiological characteristics of Geodermatophilaceae in Shapotou National Desert Ecological Reserve

    PubMed Central

    Sun, Hong-Min; Zhang, Tao; Yu, Li-Yan; Sen, Keya; Zhang, Yu-Qin

    2015-01-01

    The goal of this study was to gain insight into the diversity of culturable actinobacteria in desert soil crusts and to determine the physiological characteristics of the predominant actinobacterial group in these crusts. Culture-dependent method was employed to obtain actinobacterial strains from desert soil samples collected from Shapotou National Desert Ecological Reserve (NDER) located in Tengger Desert, China. A total of 376 actinobacterial strains were isolated and 16S rRNA gene sequences analysis indicated that these isolates belonged to 29 genera within 18 families, among which the members of the family Geodermatophilaceae were predominant. The combination of 16S rRNA gene information and the phenotypic data allowed these newly-isolated Geodermatophilaceae members to be classified into 33 “species clusters,” 11 of which represented hitherto unrecognized species. Fermentation broths from 19.7% of the isolated strains showed activity in at least one of the six screens for antibiotic activity. These isolates exhibited bio-diversity in enzymatic characteristics and carbon utilization profiles. The physiological characteristics of the isolates from different types of crusts or bare sand samples were specific to their respective micro-ecological environments. Our study revealed that members of the family Geodermatophilaceae were ubiquitous, abundant, and diverse in Shapotou NDER, and these strains may represent a new major group of potential functional actinobacteria in desert soil. PMID:26483778

  20. Assessment of Self-Motivation and Selected Physiological Characteristics as Predictors of Adherence to Exercise in a Corporate Setting.

    ERIC Educational Resources Information Center

    Custer, Sally J.; Doty, Charles R.

    1992-01-01

    Study examined self-motivation and selected physiological characteristics as predictors of whether employees would complete a structured corporate exercise/fitness program. Researchers surveyed employees regarding physiological health, self-motivation, and adherence. They found no significant positive relationship between self-motivation scores…

  1. Transcriptome analysis reveals physiological characteristics required for magnetosome formation in Magnetospirillum gryphiswaldense MSR-1.

    PubMed

    Wang, Xu; Wang, Qing; Zhang, Yang; Wang, Yinjia; Zhou, Yuan; Zhang, Weijia; Wen, Tong; Li, Li; Zuo, Meiqing; Zhang, Ziding; Tian, Jiesheng; Jiang, Wei; Li, Ying; Wang, Lei; Li, Jilun

    2016-06-01

    Magnetosome synthesis ability of Magnetospirillum gryphiswaldense MSR-1 in an autofermentor can be precisely controlled through strict control of dissolved oxygen concentration. In this study, using transcriptome data we discovered gene transcriptional differences and compared physiological characteristics of MSR-1 cells cultured under aerobic (high-oxygen) and micro-aerobic (low-oxygen) conditions. The results showed that 77 genes were up-regulated and 95 genes were down-regulated significantly under micro-aerobic situation. These genes were involved primarily in the categories of cell metabolism, transport, regulation and unknown-function proteins. The nutrient transport and physiological metabolism were slowed down under micro-aerobic condition, whereas dissimilatory denitrification pathways were activated and it may supplemental energy was made available for magnetosome synthesis. The result suggested that the genes of magnetosome membrane proteins (Mam and Mms) are not directly regulated by oxygen level, or are constitutively expressed. A proposed regulatory network of differentially expressed genes reflects the complexity of physiological metabolism in MSR-1, and suggests that some yet-unknown functional proteins play important roles such as ferric iron uptake and transport during magnetosome synthesis. The transcriptome data provides a holistic view of the responses of MSR-1 cells to differing oxygen levels. This approach will give new insights into general principles of magnetosome formation. PMID:27043321

  2. AFM Structural Characterization of Drinking Water Biofilm under Physiological Conditions

    EPA Science Inventory

    Due to the complexity of mixed culture drinking water biofilm, direct visual observation under in situ conditions has been challenging. In this study, atomic force microscopy (AFM) revealed the three dimensional morphology and arrangement of drinking water relevant biofilm in air...

  3. Physiological responses to water stress and waterlogging in Nothofagus species.

    PubMed

    Sun, O J; Sweet, G B; Whitehead, D; Buchan, G D

    1995-10-01

    Gas exchange and water relations were investigated in Nothofagus solandri var. cliffortioides (Hook. f.) Poole (mountain beech) and Nothofagus menziesii (Hook. f.) Oerst (silver beech) seedlings in response to water stress and waterlogging. At soil matric potentials (Psi(soil)) above -0.005 MPa, N. solandri had significantly higher photosynthetic rates (A), and stomatal and residual conductances (g(sw) and g(rc)), and lower predawn xylem water potentials (Psi(predawn)) than N. menziesii. The relative tolerance of plants to water stress was defined in terms of critical soil matric potential (Psi(cri)) and lethal xylem water potential (Psi(lethal)). The estimated values of Psi(cri) and Psi(lethal) were -1.2 and -7 MPa, respectively, for N. solandri, and -0.7 and -4 MPa, respectively, for N. menziesii. Photosynthesis was sustained to a xylem water potential (Psi(xylem)) of -7 MPa in N. solandri compared with -4 MPa in N. menziesii. Following rewatering, both A and Psi(xylem) recovered quickly in N. solandri, whereas the two variables recovered more slowly in N. menziesii. During the development of water stress, nonstomatal inhibition significantly affected A in both N. solandri and N. menziesii. Nothofagus menziesii was more susceptible to inhibition of A by waterlogging than N. solandri. However, the tolerance of N. solandri to severe waterlogging was also limited as a result of a failure to form adventitious roots, suggesting a lack of adaptation to these conditions. The differences in tolerance to water stress and waterlogging between the two species are consistent with the distribution patterns of N. solandri and N. menziesii in New Zealand. PMID:14965996

  4. Water uptake in barley grain: Physiology; genetics and industrial applications.

    PubMed

    Cu, Suong; Collins, Helen M; Betts, Natalie S; March, Timothy J; Janusz, Agnieszka; Stewart, Doug C; Skadhauge, Birgitte; Eglinton, Jason; Kyriacou, Bianca; Little, Alan; Burton, Rachel A; Fincher, Geoffrey B

    2016-01-01

    Water uptake by mature barley grains initiates germination and is the first stage in the malting process. Here we have investigated the effects of starchy endosperm cell wall thickness on water uptake, together with the effects of varying amounts of the wall polysaccharide, (1,3;1,4)-β-glucan. In the latter case, we examined mutant barley lines from a mutant library and transgenic barley lines in which the (1,3;1,4)-β-glucan synthase gene, HvCslF6, was down-regulated by RNA interference. Neither cell wall thickness nor the levels of grain (1,3;1,4)-β-glucan were significantly correlated with water uptake but are likely to influence modification during malting. However, when a barley mapping population was phenotyped for rate of water uptake into grain, quantitative trait locus (QTL) analysis identified specific regions of chromosomes 4H, 5H and 7H that accounted for approximately 17%, 18% and 11%, respectively, of the phenotypic variation. These data indicate that variation in water uptake rates by elite malting cultivars of barley is genetically controlled and a number of candidate genes that might control the trait were identified under the QTL. The genomics data raise the possibility that the genetic variation in water uptake rates might be exploited by breeders for the benefit of the malting and brewing industries. PMID:26566843

  5. Water distribution characteristics of spray nozzles in a cooling tower

    NASA Astrophysics Data System (ADS)

    Vitkovic, Pavol

    2015-05-01

    Water distribution characteristics of spray nozzles with spray plates used to distribute cooling water to the cooling fills in a cooling tower is one of the important parameters for the selection of nozzles. Water distribution characteristic describes the distribution of water from the axis of the nozzle along a fill. One of the parameters affecting the water distribution characteristic of the nozzle is airflow velocity of counter flow airstream. Water distribution characteristics are commonly measured using by a set of containers. The problem with this method of the measurement of characteristics is block of the airflow with collections of containers. Therefore, this work is using the visualization method.

  6. Bioenergetics and thermal physiology of American water shrews (Sorex palustris).

    PubMed

    Gusztak, R W; Macarthur, R A; Campbell, K L

    2005-02-01

    Rates of O(2) consumption and CO(2) production, telemetered body temperature (T(b)) and activity level were recorded from adult and subadult water shrews (Sorex palustris) over an air temperature (T(a)) range of 3-32 degrees C. Digesta passage rate trials were conducted before metabolic testing to estimate the minimum fasting time required for water shrews to achieve a postabsorptive state. Of the 228 metabolic trials conducted on 15 water shrews, 146 (64%) were discarded because the criteria for inactivity were not met. Abdominal T(b) of S. palustris was independent of T(a) and averaged 38.64 +/- 0.07 degrees C. The thermoneutral zone extended from 21.2 degrees C to at least 32 degrees C. Our estimate of the basal metabolic rate for resting, postabsorptive water shrews (96.88 +/- 2.93 J g(-1) h(-1) or 4.84 +/- 0.14 ml O(2) g(-1) h(-1)) was three times the mass-predicted value, while their minimum thermal conductance in air (0.282 +/- 0.013 ml O(2) g(-1) h(-1)) concurred with allometric predictions. The mean digesta throughput time of water shrews fed mealworms (Tenebrio molitor) or ground meat was 50-55 min. The digestibility coefficients for metabolizable energy (ME) of water shrews fed stickleback minnows (Culaea inconstans) and dragonfly nymphs (Anax spp. and Libellula spp.) were 85.4 +/- 1.3% and 82.8 +/- 1.1%, respectively. The average metabolic rate (AMR) calculated from the gas exchange of six water shrews at 19-22 degrees C (208.0 +/- 17.0 J g(-1) h(-1)) was nearly identical to the estimate of energy intake (202.9 +/- 12.9 J g(-1) h(-1)) measured for these same animals during digestibility trials (20 degrees C). Based on 24-h activity trials and our derived ME coefficients, the minimum daily energy requirement of an adult (14.4 g) water shrew at T(a) = 20 degrees C is 54.0 kJ, or the energetic equivalent of 14.7 stickleback minnows. PMID:15592850

  7. Sugarcane growth and physiological responses to water deficit stress on organic and sand soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sugarcane (Saccharum spp.) genotype selection has been more successful for organic (muck) than sand soils in Florida, perhaps due to differences in water availability. A greenhouse study was conducted at Canal Point, Florida to compare sugarcane physiological responses to water deficit stress during...

  8. Physiological failures in Zea mays during water-stress: opportunities for improvement

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maintaining high photosynthetic yield in water-stressed maize plants is a present priority for agriculture, and will likely increase in importance as key food producing regions become drier in the future. Although several physiological responses to water stress in maize have been studied in isolatio...

  9. Anatomic and physiological characteristics of the ferret lateral rectus muscle and abducens nucleus.

    PubMed

    Bishop, Keith N; McClung, J Ross; Goldberg, Stephen J; Shall, Mary S

    2007-11-01

    The ferret has become a popular model for physiological and neurodevelopmental research in the visual system. We believed it important, therefore, to study extraocular whole muscle as well as single motor unit physiology in the ferret. Using extracellular stimulation, 62 individual motor units in the ferret abducens nucleus were evaluated for their contractile characteristics. Of these motor units, 56 innervated the lateral rectus (LR) muscle alone, while 6 were split between the LR and retractor bulbi (RB) muscle slips. In addition to individual motor units, the whole LR muscle was evaluated for twitch, tetanic peak force, and fatigue. The abducens nucleus motor units showed a twitch contraction time of 15.4 ms, a mean twitch tension of 30.2 mg, and an average fusion frequency of 154 Hz. Single-unit fatigue index averaged 0.634. Whole muscle twitch contraction time was 16.7 ms with a mean twitch tension of 3.32 g. The average fatigue index of whole muscle was 0.408. The abducens nucleus was examined with horseradish peroxidase conjugated with the subunit B of cholera toxin histochemistry and found to contain an average of 183 motoneurons. Samples of LR were found to contain an average of 4,687 fibers, indicating an LR innervation ratio of 25.6:1. Compared with cat and squirrel monkeys, the ferret LR motor units contract more slowly yet more powerfully. The functional visual requirements of the ferret may explain these fundamental differences. PMID:17717110

  10. Microbiological Characteristics and Physiological Functionality of New Records of Yeasts from Wild Flowers in Yokjido, Korea

    PubMed Central

    Hyun, Se-Hee

    2014-01-01

    Two new yeast records, Cryptococcus adeliensis YJ19-2 and Cryptococcus uzbekistanensis YJ10-4 were screened from 60 yeasts strains that were isolated and identified from wild flowers in Yokjido, Gyeongsangnam-do, Korea. The morphological and cultural characteristics of the newly recorded yeasts and the physiological functionalities of the supernatants and cell-free extracts obtained from their cultures were investigated. The two newly recorded yeasts did not form ascospores and pseudomycelia. They also grew well in yeast extract-peptone-dextrose broth. C. uzbekistanensis YJ10-4 grew in a vitamin-free medium and was also tolerant to sugar and salt. Antihypertensive angiotensin I-converting enzyme inhibitory activity of the supernatant from C. adeliensis YJ19-2 was high (71.8%) and its cell-free extract also showed very high (81.2%) antidiabetic á-glucosidase inhibitory activity. PMID:25071392

  11. Physiological Characteristics and Anti-obesity Effect of Lactobacillus plantarum Q180 Isolated from Feces

    PubMed Central

    Park, Sun-Young; Cho, Seong-A; Kim, Sae-Hun; Lim, Sang-Dong

    2014-01-01

    Obesity is strongly associated with several metabolic and chronic diseases and has become a major public health problem of worldwide concern. This study aimed to investigate the physiological characteristics and anti-obesity effects of Lactobacillus plantarum Q180. Lactobacillus plantarum Q180 was isolated from the faces of healthy adults and found to have a lipase inhibitory activity of 83.61±2.32% and inhibited adipocyte differentiation of 3T3-L1 cells (14.63±1.37%) at a concentration of 100 μg/mL. The strain was investigated for its physiological characteristics. The optimum growth temperature of L. plantarum Q180 was 37℃. Lactobacillus plantarum Q180 showed higher sensitivity to novobiocin in a comparison of fifteen different antibiotics and showed the highest resistance to rifampicin, polymyxin B and vancomycin. The strain showed higher β-galactosidase and N-acetyl-β-glucosaminidase activities. It also did not produce carcinogenic enzymes such as β-glucuronidase. The survival rate of L. plantarum Q180 in MRS broth containing 0.3% bile was 97.8%. Moreover, the strain showed a 97.2% survival rate after incubation for 3 h in pH 2.0. Lactobacillus plantarum Q180 was displayed resistance to Escherichia coli, Salmonella Typhimurium and Staphylococcus aureus with rates of 55.6%, 38.0% and 47.6%, respectively. These results demonstrate that L. plantarum Q180 has potential as a probiotic with anti-obesity effects. PMID:26761499

  12. The science of badminton: game characteristics, anthropometry, physiology, visual fitness and biomechanics.

    PubMed

    Phomsoupha, Michael; Laffaye, Guillaume

    2015-04-01

    Badminton is a racket sport for two or four people, with a temporal structure characterized by actions of short duration and high intensity. This sport has five events: men's and women's singles, men's and women's doubles, and mixed doubles, each requiring specific preparation in terms of technique, control and physical fitness. Badminton is one of the most popular sports in the world, with 200 million adherents. The decision to include badminton in the 1992 Olympics Game increased participation in the game. This review focuses on the game characteristics, anthropometry, physiology, visual attributes and biomechanics of badminton. Players are generally tall and lean, with an ectomesomorphic body type suited to the high physiological demands of a match. Indeed, a typical match characteristic is a rally time of 7 s and a resting time of 15 s, with an effective playing time of 31%. This sport is highly demanding, with an average heart rate (HR) of over 90% of the player's maximal HR. The intermittent actions during a game are demanding on both the aerobic and anaerobic systems: 60-70% on the aerobic system and approximately 30% on the anaerobic system, with greater demand on the alactic metabolism with respect to the lactic anaerobic metabolism. The shuttlecock has an atypical trajectory, and the players perform specific movements such as lunging and jumping, and powerful strokes using a specific pattern of movement. Lastly, badminton players are visually fit, picking up accurate visual information in a short time. Knowledge of badminton can help to improve coaching and badminton skills. PMID:25549780

  13. Physiological and anthropometric characteristics of Australian junior national, state, and novice volleyball players.

    PubMed

    Gabbett, Tim; Georgieff, Boris

    2007-08-01

    The purpose of this study was to investigate the physiological and anthropometric characteristics of junior volleyball players competing at the elite, semi-elite, and novice levels and to establish performance standards for these athletes. One hundred and fifty-three junior national (N = 14 males; N = 20 females), state (N = 16 males; N = 42 females), and novice (N = 27 males; N = 34 females) volleyball players participated in this study. Subjects underwent measurements of standard anthropometry (body mass, height, standing reach height, and sum of 7 skinfolds), lower-body muscular power (vertical jump and spike jump), upper-body muscular power (overhead medicine ball throw), speed (5-m and 10-m sprint), agility (T-test), and estimated maximal aerobic power (multistage fitness test) during the competitive phase of the season, after obtaining a degree of match fitness. Significant differences (p < 0.05) were detected among junior national, state, and novice volleyball players for height, standing reach height, skinfold thickness, lower-body muscular power, agility, and estimated maximal aerobic power, with the physiological and anthropometric characteristics of players typically improving with increases in playing level. Male players were taller, heavier, leaner, and had greater standing reach height, speed, agility, muscular power, and estimated maximal aerobic power than female players. These findings provide normative data and performance standards for junior volleyball players competing at the elite, semi-elite, and novice levels. Given the improvements in lower-body muscular power, agility, and estimated maximal aerobic power with increased playing level, and given the importance of these qualities to competitive performances, conditioning coaches should train these qualities to improve the playing performances of junior volleyball players. PMID:17685708

  14. Physiological characteristics of tropical rain forest tree species: A basis for the development of silvicultural technology

    PubMed Central

    SASAKI, Satohiko

    2008-01-01

    The physiological characteristics of the dominant tree species in the tropical rain forest mainly belonging to dipterocarps as well as the environmental conditions especially for the light in the forest were studied to establish the silvicultural system for the forest regeneration in the tropical South Asia. The flowering patterns of the dipterocarp trees are usually irregular and unpredictable, which make difficult to collect sufficient seeds for raising the seedlings. The field survey revealed the diverged features of the so-called gregarious or simultaneous flowering of various species of this group. Appropriate conditions and methods for the storage of the seeds were established according to the detailed analyses of the morphological and physiological characteristics of the seeds such as the low temperature tolerance and the moisture contents. The intensity and spectra of the light in the forest primarily determine the growth and the morphological development of the seedlings under the canopy. Based on the measurements of the diffused light at the sites in the tropical forest in the varying sunlight, the parameters such as “the steady state of the diffuse light” and “the turning point” were defined, which were useful to evaluate the light conditions in the forest. To improve the survival of the transplanted seedlings, a planting method of “the bare-root seedlings”, the seedlings easy to be handled by removal of all leaves, soil and pots, was developed. Its marked efficiency was proved with various dipterocarps and other tropical trees by the field trial in the practical scale. Tolerance of the various species to the extreme environmental conditions such as fires, acid soils and drought were examined by the experiments and the field survey, which revealed marked adaptability of Shorea roxburghii as a potential species for regeneration of the tropical forests. PMID:18941286

  15. [Effects of selenite addition on selenium absorption, root morphology and physiological characteristics of rape seedlings].

    PubMed

    Liu, Xin-wei; Wang, Qiao-lan; Duan, Bi-hui; Lin, Ya-meng; Zhao, Xiao-hu; Hu, Cheng-xiao; Zhao, Zhu-qing

    2015-07-01

    Abstract: The rape (Brassica napus L. cv. Xiangnongyou 571) was chosen as the experimental material to undergo solution cultivation at seedling stage to investigate the effects of selenite addition on the selenium (Se) absorption and distribution, root morphology and physiological characteristics of rape seedlings. The results showed that the bioaccumulation ability of Se decreased significantly with increasing the Se application rate, but the Se distribution coefficient remained around 0.9 with no significant influence. The application of 10 µmol . L-1 selenite stimulated the growth of rape seedlings through improving the root physiological characteristics and root morphology significantly, including significantly increasing the production of superoxide radical (O2∙-) rate and the activities of superoxide dismutase (SOD), peroxidase (POD) and fungal catalase (CAT) in the root system, which resulted in a reduction of the lipids peroxidation (MDA) content as much as 26.0%, consequently increasing the root activity as much as 17.4%. The promoting degrees of selenite on root morphological parameters were from strong to weak in such a tendency: root volume > total surface area > number of root forks > total root length > number of root tips > average diameter. However, such positive effects had no significant difference with those in treatment with 1 µmol . L-1 selenite, indicating that small amounts (≤ 10 Lmol . L-1) of selenite were able to increase the activity of antioxidant enzymes and reduce the content of MDA in root system, which could increase root activity and improve root morphology, hence increased the biomass of rape seedlings. PMID:26710631

  16. Methane emissions from beef and dairy cattle: quantifying the effect of physiological stage and diet characteristics.

    PubMed

    Ricci, P; Rooke, J A; Nevison, I; Waterhouse, A

    2013-11-01

    The prediction of methane outputs from ruminant livestock data at farm, national, and global scales is a vital part of greenhouse gas calculations. The objectives of this work were to quantify the effect of physiological stage (lactating or nonlactating) on predicting methane (CH4) outputs and to illustrate the potential improvement for a beef farming system of using more specific mathematical models to predict CH4 from cattle at different physiological stages and fed different diet types. A meta-analysis was performed on 211 treatment means from 38 studies where CH4, intake, animal, and feed characteristics had been recorded. Additional information such as type of enterprise, diet type, physiological stage, CH4 measurement technique, intake restriction, and CH4 reduction treatment application from these studies were used as classificatory factors. A series of equations for different physiological stages and diet types based on DMI or GE intake explained 96% of the variation in observed CH4 outputs (P<0.001). Resulting models were validated with an independent dataset of 172 treatment means from 20 studies. To illustrate the scale of improvement on predicted CH4 outputs from the current whole-farm prediction approach (Intergovernmental Panel on Climate Change [IPCC]), equations developed in the present study (NewEqs) were compared with the IPCC equation {CH4 (g/d)=[(GEI×Ym)×1,000]/55.65}, in which GEI is GE intake and Ym is the CH4 emission factor, in calculating CH4 outputs from 4 diverse beef systems. Observed BW and BW change data from cows with calves at side grazing either hill or lowland grassland, cows and overwintering calves and finishing steers fed contrasting diets were used to predict energy requirements, intake, and CH4 outputs. Compared with using this IPCC equation, NewEqs predicted up to 26% lower CH4 on average from individual lactating grazing cows. At the herd level, differences between equation estimates from 10 to 17% were observed in total

  17. Physiological and functional characteristics of Propionibacterium strains of the poultry microbiota and relevance for the development of probiotic products.

    PubMed

    Argañaraz-Martínez, Eloy; Babot, Jaime D; Apella, María C; Perez Chaia, Adriana

    2013-10-01

    The prevention and control of pathogens colonization through probiotics administration in poultry feeding is of increasing interest. The genus Propionibacterium is an attractive candidate for the development of probiotic cultures as they produce short chain fatty acids (SCFA) by carbohydrates fermentation. The presence of strains of this genus in hens of conventional production systems and backyard hens was investigated. Propionibacteria were isolated from the intestine and identified by physiological and biochemical tests. PCR amplification of the 16S rRNA gene of the isolates was performed and products were compared with sequences from databases. The presence of the genus Propionibacterium was demonstrated in 26% of hens and Propionibacterium acidipropionici and Propionibacterium avidum were the identified species. A comparative study of their physiological and functional characteristics was performed. P. acidipropionici strains were the most resistant to in vitro gastrointestinal digestion, but the adhesion to intestinal tissue was strain dependent. Some differences were found between both species with respect to their growth and SCFA production in an in vitro cecal water model, but all the strains were metabolically active. The production of SCFA in cecal slurries inoculated with the strain P. acidipropionici LET 105 was 30% higher than in non-inoculated samples. SCFA concentrations obtained were high enough to inhibit Salmonella enterica serovar Enteritidis when assayed in a cecal water model. P. acidipropionici LET 105 was also able to compete with Salmonella for adhesion sites on the intestinal mucosa in ex vivo assays. Results contribute to the knowledge of the species diversity of the genus Propionibacterium in the intestine of poultry and provide evidence of their potential for probiotics products development. PMID:23973927

  18. Water Landing Characteristics of a Reentry Capsule

    NASA Technical Reports Server (NTRS)

    1958-01-01

    Water Landing Characteristics of a Reentry Capsule. Experimental and theoretical investigations have been made to determine the water-landing characteristics of a conical-shaped reentry capsule having a segment of a sphere as the bottom. For the experimental portion of the investigation, a 1/12-scale model capsule and a full-scale capsule were tested for nominal flight paths of 65 deg and 90 deg (vertical), a range of contact attitudes from -30 deg to 30 deg, and a full-scale vertical velocity of 30 feet per second at contact. Accelerations were measured by accelerometers installed at the centers of gravity of the model and full-scale capsules. For the model test the accelerations were measured along the X-axis (roll) and Z-axis (yaw) and for the full-scale test they were measured along the X-axis (roll), Y-axis (pitch), and Z-axis (yaw). Motions and displacements of the capsules that occurred after contact were determined from high-speed motion pictures. The theoretical investigation was conducted to determine the accelerations that might occur along the X-axis when the capsule contacted the water from a 90 deg flight path at a 0 deg attitude. Assuming a rigid body, computations were made from equations obtained by utilizing the principle of the conservation of momentum. The agreement among data obtained from the model test, the full-scale test, and the theory was very good. The accelerations along the X-axis, for a vertical flight path and 0 deg attitude, were in the order of 40g. For a 65 deg flight path and 0 deg attitude, the accelerations along the X-axis were in the order of 50g. Changes in contact attitude, in either the positive or negative direction from 0 deg attitude, considerably reduced the magnitude of the accelerations measured along the X-axis. Accelerations measured along the Y- and Z-axes were relatively small at all test conditions. [Entire movie available on DVD from CASI as Doc ID 20070030955. Contact help@sti.nasa.gov

  19. Metabolic and Physiological Characteristics of Novel Cultivars from Serpentinite Seep Fluids

    NASA Astrophysics Data System (ADS)

    Nelson, B.; Chowdhury, S.; Brazelton, W. J.; Schrenk, M. O.

    2011-12-01

    Subsurface waters associated with the alteration of ultramafic rocks become highly reducing and alkaline through a process known as serpentinization. As habitat, these fluids are in many ways metabolically constraining but can provide sufficient energy for chemolithotrophy. As part of an ongoing effort to characterize these communities, heterotrophic enrichment cultures and anaerobic microcosms were initiated with alkaline waters found at three geographically and geochemically distinct sites of active serpentinization. These include the Northern Apennine ophiolite in the Ligurian region of Italy, the Tablelands ophiolite at Gros Morne National Park, Canada and the Coast Range ophiolite at McLaughlin Natural Reserve, California. Enrichment cultures at pH 11 yielded numerous isolates related to Proteobacteria and Firmicutes, some of which are closely related to other cultivars from high pH and subsurface environments. Anaerobic water samples were amended with combinations of electron donors (hydrogen, complex organics, acetate) and acceptors (ferric iron, sulfate) in a block design. After several weeks of incubation, DNA was extracted from cell concentrations and community differences were compared by TRFLP. Of particular interest is the isolation of a putative iron reducing Firmicute from samples enriched with complex organic compounds and ferric citrate. Ongoing studies are aimed at characterizing the physiology of these isolates. These data provide important insights into the metabolic potential of serpentinite subsurface ecosystems, and are a complement to culture-independent genomic analyses.

  20. Water protein dynamic coupling and new opportunities for probing it at low to physiological temperatures in aqueous solutions

    SciTech Connect

    Mamontov, Eugene; Chu, Xiang-Qiang

    2012-01-01

    Both the structure and dynamics of biomolecules are known to be essential for their biological function. In the dehydrated state, the function of biomolecules, such as proteins, is severely impeded, so hydration is required for bioactivity. The dynamics of the hydrated biomolecules and their hydration water are related - but how closely? The problem involves several layers of complexity. Even for water in the bulk state, the contribution from various dynamic components to the overall dynamics is not fully understood. In biological systems, the effects of confinement on the hydration water further complicate the picture. Even if the various components of the hydration water dynamics are properly understood, which of them are coupled to the protein dynamics, and how? The studies of protein dynamics over the wide temperature range, from physiological to low temperatures, provide some answers to these question. At low temperatures, both the protein and its hydration water behave as solids, with only vibrational degrees of freedom. As the temperature is increased, non-vibrational dynamic components start contributing to the measurable dynamics and eventually become dominant at physiological temperatures. Thus, the temperature dependence of the dynamics of protein and its hydration water may allow probing various dynamic components separately. In order to suppress the water freezing, the low-temperature studies of protein rely on either low-hydrated samples (essentially, hydrated protein powders), or cryo-protective solutions. Both approaches introduce the hydration environments not characteristic of the protein environments in living systems, which are typically aqueous protein solutions of various concentrations. In this paper, we discuss the coupling between the dynamic components of the protein and its hydration water by critical examining of the existing literature, and then propose that proteins can be studied in an aqueous solution that is remarkably similar in

  1. Water Landing Characteristics of a Reentry Capsule

    NASA Technical Reports Server (NTRS)

    1958-01-01

    Experimental and theoretical investigations have been made to determine the water-landing characteristics of a conical-shaped reentry capsule having a segment of a sphere as the bottom. For the experimental portion of the investigation, a 1/12-scale model capsule and a full-scale capsule were tested for nominal flight paths of 65 deg and 90 deg (vertical), a range of contact attitudes from -30 deg to 30 deg, and a full-scale vertical velocity of 30 feet per second at contact. Accelerations were measured by accelerometers installed at the centers of gravity of the model and full-scale capsules. For the model test the accelerations were measured along the X-axis (roll) and Z-axis (yaw) and for the full-scale test they were measured along the X-axis (roll), Y-axis (pitch), and Z-axis (yaw). Motions and displacements of the capsules that occurred after contact were determined from high-speed motion pictures. The theoretical investigation was conducted to determine the accelerations that might occur along the X-axis when the capsule contacted the water from a 90 deg flight path at a 0 deg attitude. Assuming a rigid body, computations were made from equations obtained by utilizing the principle of the conservation of momentum. The agreement among data obtained from the model test, the full-scale test, and the theory was very good. The accelerations along the X-axis, for a vertical flight path and 0 deg attitude, were in the order of 40g. For a 65 deg flight path and 0 deg attitude, the accelerations along the X-axis were in the order of 50g. Changes in contact attitude, in either the positive or negative direction from 0 deg attitude, considerably reduced the magnitude of the accelerations measured along the X-axis. Accelerations measured along the Y- and Z-axes were relatively small at all test conditions.

  2. Anthropometric and physiological characteristics of Melanesian futsal players: a first approach to talent identification in Oceania

    PubMed Central

    Zongo, P; Chamari, K; Chaouachi, A; Michalak, E; Dellal, A; Castagna, C; Hue, O

    2015-01-01

    This study assessed the anthropometric and physiological characteristics of elite Melanesian futsal players in order to determine the best performance predictors. Physiological parameters of performance were measured in 14 Melanesian (MEL-G, 24.4±4.4 yrs) and 8 Caucasian (NMEL-G, 22.9±4.9) elite futsal players, using tests of jump-and-reach (CMJ), agility (T-Test), repeated sprint ability (RSA), RSA with change-of-direction (RSA-COD), sprints with 5 m, 10 m, 15 m, and 30 m lap times, and aerobic fitness with the 30-15 intermittent fitness test (30-15 IFT). The anthropometric data revealed significantly lower height for MEL-G compared with NMEL-G: 1.73±0.05 and 1.80±0.08 m, respectively; P = 0.05. The CMJ was significantly higher for MEL-G than NMEL-G: 50.4±5.9 and 45.2±4.3 cm, respectively; P = 0.05. T-Test times were significantly lower for MEL-G than NMEL-G: 10.47±0.58 and 11.01±0.64 seconds, respectively; P = 0.05. MEL-G height was significantly related to CMJ (r = 0.706, P = 0.01), CMJpeakP (r = 0.709, P = 0.01) and T-Test (r = 0.589, P = 0.02). No significant between-group differences were observed for sprint tests or 30-15 IFT, including heart rate and estimated VO2max. Between groups, the percentage decrement (%Dec) in RSA-COD was significantly lower in MEL-G than NMEL-G (P = 0.05), although no significant difference was noted between RSA and RSA-COD. Within groups, no significant difference was observed between %Dec in RSA or RSA-COD; P = 0.697. This study presents specific anthropometric (significantly lower height) and physiological (significantly greater agility) reference values in Melanesians, which, taken together, might help coaches and physical fitness trainers to optimize elite futsal training and talent identification in Oceania. PMID:26060337

  3. Anthropometric and physiological characteristics of Melanesian futsal players: a first approach to talent identification in Oceania.

    PubMed

    Galy, O; Zongo, P; Chamari, K; Chaouachi, A; Michalak, E; Dellal, A; Castagna, C; Hue, O

    2015-06-01

    This study assessed the anthropometric and physiological characteristics of elite Melanesian futsal players in order to determine the best performance predictors. Physiological parameters of performance were measured in 14 Melanesian (MEL-G, 24.4±4.4 yrs) and 8 Caucasian (NMEL-G, 22.9±4.9) elite futsal players, using tests of jump-and-reach (CMJ), agility (T-Test), repeated sprint ability (RSA), RSA with change-of-direction (RSA-COD), sprints with 5 m, 10 m, 15 m, and 30 m lap times, and aerobic fitness with the 30-15 intermittent fitness test (30-15 IFT). The anthropometric data revealed significantly lower height for MEL-G compared with NMEL-G: 1.73±0.05 and 1.80±0.08 m, respectively; P = 0.05. The CMJ was significantly higher for MEL-G than NMEL-G: 50.4±5.9 and 45.2±4.3 cm, respectively; P = 0.05. T-Test times were significantly lower for MEL-G than NMEL-G: 10.47±0.58 and 11.01±0.64 seconds, respectively; P = 0.05. MEL-G height was significantly related to CMJ (r = 0.706, P = 0.01), CMJpeakP (r = 0.709, P = 0.01) and T-Test (r = 0.589, P = 0.02). No significant between-group differences were observed for sprint tests or 30-15 IFT, including heart rate and estimated VO2max. Between groups, the percentage decrement (%Dec) in RSA-COD was significantly lower in MEL-G than NMEL-G (P = 0.05), although no significant difference was noted between RSA and RSA-COD. Within groups, no significant difference was observed between %Dec in RSA or RSA-COD; P = 0.697. This study presents specific anthropometric (significantly lower height) and physiological (significantly greater agility) reference values in Melanesians, which, taken together, might help coaches and physical fitness trainers to optimize elite futsal training and talent identification in Oceania. PMID:26060337

  4. Identification of Physiological Traits for Early Detecting Water Deficit Stress in Sugarcane

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sugarcane (Saccharum spp.) genotype selection has been more successful for organic (muck) than sand soils in Florida. Water deficit stress during its formative growth phase may limit sugarcane growth and yields on Florida sand soils. Therefore, identifying proper physiological traits will help scien...

  5. Genotypic differences in architectural and physiological responses to water restriction in rose bush.

    PubMed

    Li-Marchetti, Camille; Le Bras, Camille; Relion, Daniel; Citerne, Sylvie; Huché-Thélier, Lydie; Sakr, Soulaiman; Morel, Philippe; Crespel, Laurent

    2015-01-01

    The shape and, therefore, the architecture of the plant are dependent on genetic and environmental factors such as water supply. The architecture determines the visual quality, a key criterion underlying the decision to purchase an ornamental potted plant. The aim of this study was to analyze genotypic responses of eight rose bush cultivars to alternation of water restriction and re-watering periods, with soil water potential of -20 and -10 kPa respectively. Responses were evaluated at the architectural level through 3D digitalization using six architectural variables and at the physiological level by measuring stomatal conductance, water content, hormones [abscisic acid (ABA), auxin, cytokinins, jasmonic acid, and salicylic acid (SA)], sugars (sucrose, fructose, and glucose), and proline. Highly significant genotype and watering effects were revealed for all the architectural variables measured, as well as genotype × watering interaction, with three distinct genotypic architectural responses to water restriction - weak, moderate and strong - represented by Hw336, 'Baipome' and 'The Fairy,' respectively. The physiological analysis explained, at least in part, the more moderate architectural response of 'Baipome' compared to 'The Fairy,' but not that of Hw336 which is an interspecific hybrid. Such physiological responses in 'Baipome' could be related to: (i) the maintenance of the stimulation of budbreak and photosynthetic activity during water restriction periods due to a higher concentration in conjugated cytokinins (cCK) and to a lower concentration in SA; (ii) a better resumption of budbreak during the re-watering periods due to a lower concentration in ABA during this period. When associated with the six architectural descriptors, cCK, SA and ABA, which explained the genotypic differences in this study, could be used as selection criteria for breeding programs aimed at improving plant shape and tolerance to water restriction. PMID:26074929

  6. Genotypic differences in architectural and physiological responses to water restriction in rose bush

    PubMed Central

    Li-Marchetti, Camille; Le Bras, Camille; Relion, Daniel; Citerne, Sylvie; Huché-Thélier, Lydie; Sakr, Soulaiman; Morel, Philippe; Crespel, Laurent

    2015-01-01

    The shape and, therefore, the architecture of the plant are dependent on genetic and environmental factors such as water supply. The architecture determines the visual quality, a key criterion underlying the decision to purchase an ornamental potted plant. The aim of this study was to analyze genotypic responses of eight rose bush cultivars to alternation of water restriction and re-watering periods, with soil water potential of -20 and -10 kPa respectively. Responses were evaluated at the architectural level through 3D digitalization using six architectural variables and at the physiological level by measuring stomatal conductance, water content, hormones [abscisic acid (ABA), auxin, cytokinins, jasmonic acid, and salicylic acid (SA)], sugars (sucrose, fructose, and glucose), and proline. Highly significant genotype and watering effects were revealed for all the architectural variables measured, as well as genotype × watering interaction, with three distinct genotypic architectural responses to water restriction – weak, moderate and strong – represented by Hw336, ‘Baipome’ and ‘The Fairy,’ respectively. The physiological analysis explained, at least in part, the more moderate architectural response of ‘Baipome’ compared to ‘The Fairy,’ but not that of Hw336 which is an interspecific hybrid. Such physiological responses in ‘Baipome’ could be related to: (i) the maintenance of the stimulation of budbreak and photosynthetic activity during water restriction periods due to a higher concentration in conjugated cytokinins (cCK) and to a lower concentration in SA; (ii) a better resumption of budbreak during the re-watering periods due to a lower concentration in ABA during this period. When associated with the six architectural descriptors, cCK, SA and ABA, which explained the genotypic differences in this study, could be used as selection criteria for breeding programs aimed at improving plant shape and tolerance to water restriction. PMID

  7. Physiological plasticity to water flow habitat in the damselfish, Acanthochromis polyacanthus: linking phenotype to performance.

    PubMed

    Binning, Sandra A; Ros, Albert F H; Nusbaumer, David; Roche, Dominique G

    2015-01-01

    The relationships among animal form, function and performance are complex, and vary across environments. Therefore, it can be difficult to identify morphological and/or physiological traits responsible for enhancing performance in a given habitat. In fishes, differences in swimming performance across water flow gradients are related to morphological variation among and within species. However, physiological traits related to performance have been less well studied. We experimentally reared juvenile damselfish, Acanthochromis polyacanthus, under different water flow regimes to test 1) whether aspects of swimming physiology and morphology show plastic responses to water flow, 2) whether trait divergence correlates with swimming performance and 3) whether flow environment relates to performance differences observed in wild fish. We found that maximum metabolic rate, aerobic scope and blood haematocrit were higher in wave-reared fish compared to fish reared in low water flow. However, pectoral fin shape, which tends to correlate with sustained swimming performance, did not differ between rearing treatments or collection sites. Maximum metabolic rate was the best overall predictor of individual swimming performance; fin shape and fish total length were 3.3 and 3.7 times less likely than maximum metabolic rate to explain differences in critical swimming speed. Performance differences induced in fish reared in different flow environments were less pronounced than in wild fish but similar in direction. Our results suggest that exposure to water motion induces plastic physiological changes which enhance swimming performance in A. polyacanthus. Thus, functional relationships between fish morphology and performance across flow habitats should also consider differences in physiology. PMID:25807560

  8. Physiological Plasticity to Water Flow Habitat in the Damselfish, Acanthochromis polyacanthus: Linking Phenotype to Performance

    PubMed Central

    Binning, Sandra A.; Ros, Albert F. H.; Nusbaumer, David; Roche, Dominique G.

    2015-01-01

    The relationships among animal form, function and performance are complex, and vary across environments. Therefore, it can be difficult to identify morphological and/or physiological traits responsible for enhancing performance in a given habitat. In fishes, differences in swimming performance across water flow gradients are related to morphological variation among and within species. However, physiological traits related to performance have been less well studied. We experimentally reared juvenile damselfish, Acanthochromis polyacanthus, under different water flow regimes to test 1) whether aspects of swimming physiology and morphology show plastic responses to water flow, 2) whether trait divergence correlates with swimming performance and 3) whether flow environment relates to performance differences observed in wild fish. We found that maximum metabolic rate, aerobic scope and blood haematocrit were higher in wave-reared fish compared to fish reared in low water flow. However, pectoral fin shape, which tends to correlate with sustained swimming performance, did not differ between rearing treatments or collection sites. Maximum metabolic rate was the best overall predictor of individual swimming performance; fin shape and fish total length were 3.3 and 3.7 times less likely than maximum metabolic rate to explain differences in critical swimming speed. Performance differences induced in fish reared in different flow environments were less pronounced than in wild fish but similar in direction. Our results suggest that exposure to water motion induces plastic physiological changes which enhance swimming performance in A. polyacanthus. Thus, functional relationships between fish morphology and performance across flow habitats should also consider differences in physiology. PMID:25807560

  9. Profiling of Intracellular Metabolites: An Approach to Understanding the Characteristic Physiology of Mycobacterium leprae

    PubMed Central

    Miyamoto, Yuji; Mukai, Tetsu; Matsuoka, Masanori; Kai, Masanori; Maeda, Yumi; Makino, Masahiko

    2016-01-01

    Mycobacterium leprae is the causative agent of leprosy and also known to possess unique features such as inability to proliferate in vitro. Among the cellular components of M. leprae, various glycolipids present on the cell envelope are well characterized and some of them are identified to be pathogenic factors responsible for intracellular survival in host cells, while other intracellular metabolites, assumed to be associated with basic physiological feature, remain largely unknown. In the present study, to elucidate the comprehensive profile of intracellular metabolites, we performed the capillary electrophoresis-mass spectrometry (CE-MS) analysis on M. leprae and compared to that of M. bovis BCG. Interestingly, comparison of these two profiles showed that, in M. leprae, amino acids and their derivatives are significantly accumulated, but most of intermediates related to central carbon metabolism markedly decreased, implying that M. leprae possess unique metabolic features. The present study is the first report demonstrating the unique profiles of M. leprae metabolites and these insights might contribute to understanding undefined metabolism of M. leprae as well as pathogenic characteristics related to the manifestation of the disease. PMID:27479467

  10. Physiological characteristics of the extreme thermophile Caldicellulosiruptor saccharolyticus: an efficient hydrogen cell factory

    PubMed Central

    2010-01-01

    Global concerns about climate changes and their association with the use of fossil fuels have accelerated research on biological fuel production. Biological hydrogen production from hemicellulose-containing waste is considered one of the promising avenues. A major economical issue for such a process, however, is the low substrate conversion efficiency. Interestingly, the extreme thermophilic bacterium Caldicellulosiruptor saccharolyticus can produce hydrogen from carbohydrate-rich substrates at yields close to the theoretical maximum of the dark fermentation process (i.e., 4 mol H2/mol hexose). The organism is able to ferment an array of mono-, di- and polysaccharides, and is relatively tolerant to high partial hydrogen pressures, making it a promising candidate for exploitation in a biohydrogen process. The behaviour of this Gram-positive bacterium bears all hallmarks of being adapted to an environment sparse in free sugars, which is further reflected in its low volumetric hydrogen productivity and low osmotolerance. These two properties need to be improved by at least a factor of 10 and 5, respectively, for a cost-effective industrial process. In this review, the physiological characteristics of C. saccharolyticus are analyzed in view of the requirements for an efficient hydrogen cell factory. A special emphasis is put on the tight regulation of hydrogen production in C. saccharolyticus by both redox and energy metabolism. Suggestions for strategies to overcome the current challenges facing the potential use of the organism in hydrogen production are also discussed. PMID:21092203

  11. Characteristics and physiological role of surfactant-like particles secreted by entrocytes.

    PubMed

    Turan, Aasma; Gupta, Shiffalli; Mahmood, Akhtar

    2006-07-01

    Intestinal epithelium secretes novel unilamellar membranes having characteristics similar to lung surfactants and thus has been named Surfactant-like particles (SLP). The chemical analysis of the membranes revealed cholesterol/phospholipid molar ratio of 0.68-0.78, which is much distinct from that of the underlying microvillus membranes (1.34-1.49). The membrane contains 4-6 proteins with a molar weight of 30-120 kDa and is enriched with alkaline phosphatase, contains low amounts of disaccharidases but no Na+, K(+)-ATPase activity. The secretion of SLP is stimulated by fat feeding. Chronic ethanol ingestion also induces the formation of SLP in rat intestine. A number of physiological functions have been attributed to SLP, which include: (i) as a protective lubricant in intestinal lumen, (ii) a role in triacylglycerol transport, (iii) as a vehicle for the transport of luminal proteins into blood, (iv) as a stratum for the adhesion of microorganisms in intestinal lumen, and (v) a role in trans-signalling mechanism across the basolateral surface of enterocytes. PMID:16872040

  12. A novel ammonia-oxidizing archaeon from wastewater treatment plant: Its enrichment, physiological and genomic characteristics

    NASA Astrophysics Data System (ADS)

    Li, Yuyang; Ding, Kun; Wen, Xianghua; Zhang, Bing; Shen, Bo; Yang, Yunfeng

    2016-03-01

    Ammonia-oxidizing archaea (AOA) are recently found to participate in the ammonia removal processes in wastewater treatment plants (WWTPs), similar to their bacterial counterparts. However, due to lack of cultivated AOA strains from WWTPs, their functions and contributions in these systems remain unclear. Here we report a novel AOA strain SAT1 enriched from activated sludge, with its physiological and genomic characteristics investigated. The maximal 16S rRNA gene similarity between SAT1 and other reported AOA strain is 96% (with “Ca. Nitrosotenuis chungbukensis”), and it is affiliated with Wastewater Cluster B (WWC-B) based on amoA gene phylogeny, a cluster within group I.1a and specific for activated sludge. Our strain is autotrophic, mesophilic (25 °C–33 °C) and neutrophilic (pH 5.0–7.0). Its genome size is 1.62 Mb, with a large fragment inversion (accounted for 68% genomic size) inside. The strain could not utilize urea due to truncation of the urea transporter gene. The lack of the pathways to synthesize usual compatible solutes makes it intolerant to high salinity (>0.03%), but could adapt to low salinity (0.005%) environments. This adaptation, together with possibly enhanced cell-biofilm attachment ability, makes it suitable for WWTPs environment. We propose the name “Candidatus Nitrosotenuis cloacae” for the strain SAT1.

  13. Insight into characteristic features of cartilage growth plate as a physiological template for bone formation.

    PubMed

    Jaroszewicz, Jakub; Kosowska, Anna; Hutmacher, Dietmar; Swieszkowski, Wojciech; Moskalewski, Stanisław

    2016-02-01

    Cartilage growth plate is a natural template from both a biochemical and structural point of view and allows osteoblasts migration, proliferation, differentiation, and ultimately, bone formation. It is evolutionary adjusted to support bone formation within strictly defined spatial framework serving as an interesting model for studying more mechanistically aspects which might be important for specific scaffold-based bone tissue engineering strategies. Surprisingly little is known about the geometric features of this physiological template. To this purpose we analyzed cartilage growth plate from rat, mouse, and human costochondral junction and tibia. High-resolution X-ray tomography showed that pore size in the zone of provisional calcification was within 20 to 30 µm range and in the metaphysis in 35 to 50 µm range. The thickness of calcified longitudinal septa in zone of provisional calcification was 3 to 5 µm and in metaphysis 7 to 12 µm. The porosity varied from 84 to 88%. We observed that numerical values characteristic for cartilage growth plate were not significantly influenced by the species of origin, by the type of bone, or by age. In addition, electron microscopy of calcified fragments of longitudinal septa showed that the calcium aggregates were globular, connected with each other, and formed a shell covering cartilage matrix located within longitudinal septa. PMID:26453900

  14. Profiling of Intracellular Metabolites: An Approach to Understanding the Characteristic Physiology of Mycobacterium leprae.

    PubMed

    Miyamoto, Yuji; Mukai, Tetsu; Matsuoka, Masanori; Kai, Masanori; Maeda, Yumi; Makino, Masahiko

    2016-08-01

    Mycobacterium leprae is the causative agent of leprosy and also known to possess unique features such as inability to proliferate in vitro. Among the cellular components of M. leprae, various glycolipids present on the cell envelope are well characterized and some of them are identified to be pathogenic factors responsible for intracellular survival in host cells, while other intracellular metabolites, assumed to be associated with basic physiological feature, remain largely unknown. In the present study, to elucidate the comprehensive profile of intracellular metabolites, we performed the capillary electrophoresis-mass spectrometry (CE-MS) analysis on M. leprae and compared to that of M. bovis BCG. Interestingly, comparison of these two profiles showed that, in M. leprae, amino acids and their derivatives are significantly accumulated, but most of intermediates related to central carbon metabolism markedly decreased, implying that M. leprae possess unique metabolic features. The present study is the first report demonstrating the unique profiles of M. leprae metabolites and these insights might contribute to understanding undefined metabolism of M. leprae as well as pathogenic characteristics related to the manifestation of the disease. PMID:27479467

  15. A novel ammonia-oxidizing archaeon from wastewater treatment plant: Its enrichment, physiological and genomic characteristics

    PubMed Central

    Li, Yuyang; Ding, Kun; Wen, Xianghua; Zhang, Bing; Shen, Bo; Yang, Yunfeng

    2016-01-01

    Ammonia-oxidizing archaea (AOA) are recently found to participate in the ammonia removal processes in wastewater treatment plants (WWTPs), similar to their bacterial counterparts. However, due to lack of cultivated AOA strains from WWTPs, their functions and contributions in these systems remain unclear. Here we report a novel AOA strain SAT1 enriched from activated sludge, with its physiological and genomic characteristics investigated. The maximal 16S rRNA gene similarity between SAT1 and other reported AOA strain is 96% (with “Ca. Nitrosotenuis chungbukensis”), and it is affiliated with Wastewater Cluster B (WWC-B) based on amoA gene phylogeny, a cluster within group I.1a and specific for activated sludge. Our strain is autotrophic, mesophilic (25 °C–33 °C) and neutrophilic (pH 5.0–7.0). Its genome size is 1.62 Mb, with a large fragment inversion (accounted for 68% genomic size) inside. The strain could not utilize urea due to truncation of the urea transporter gene. The lack of the pathways to synthesize usual compatible solutes makes it intolerant to high salinity (>0.03%), but could adapt to low salinity (0.005%) environments. This adaptation, together with possibly enhanced cell-biofilm attachment ability, makes it suitable for WWTPs environment. We propose the name “Candidatus Nitrosotenuis cloacae” for the strain SAT1. PMID:27030530

  16. Effects of Shade Treatments on Photosynthetic Characteristics, Chloroplast Ultrastructure, and Physiology of Anoectochilus roxburghii

    PubMed Central

    Shao, Qingsong; Wang, Hongzhen; Guo, Haipeng; Zhou, Aicun; Huang, Yuqiu; Sun, Yulu; Li, Mingyan

    2014-01-01

    Anoectochilus roxburghii was grown under different shade treatments–50%, 30%, 20%, and 5% of natural irradiance–to evaluate its photosynthetic characteristics, chloroplast ultrastructure, and physiology. The highest net photosynthetic rates and stomatal conductance were observed under 30% irradiance, followed in descending order by 20%, 5%, and 50% treatments. As irradiance decreased from 50% to 30%, electron transport rate and photochemical quenching increased, while non-photochemical quenching indexes declined. Reductions in irradiance significantly increased Chl a and Chl b contents and decreased Chl a/b ratios. Chloroplast ultrastructure generally displayed the best development in leaves subjected to 30% irradiance. Under 50% irradiance, leaf protein content remained relatively stable during the first 20 days of treatment, and then increased rapidly. The highest peroxidase and superoxide dismutase levels, and the lowest catalase activities, were observed in plants subjected to the 50% irradiance treatment. Soluble sugar and malondialdehyde contents were positively correlated with irradiance levels. Modulation of chloroplast development, accomplished by increasing the number of thylakoids and grana containing photosynthetic pigments, is an important shade tolerance mechanism in A. roxburghii. PMID:24516523

  17. Effects of shade treatments on photosynthetic characteristics, chloroplast ultrastructure, and physiology of Anoectochilus roxburghii.

    PubMed

    Shao, Qingsong; Wang, Hongzhen; Guo, Haipeng; Zhou, Aicun; Huang, Yuqiu; Sun, Yulu; Li, Mingyan

    2014-01-01

    Anoectochilus roxburghii was grown under different shade treatments-50%, 30%, 20%, and 5% of natural irradiance-to evaluate its photosynthetic characteristics, chloroplast ultrastructure, and physiology. The highest net photosynthetic rates and stomatal conductance were observed under 30% irradiance, followed in descending order by 20%, 5%, and 50% treatments. As irradiance decreased from 50% to 30%, electron transport rate and photochemical quenching increased, while non-photochemical quenching indexes declined. Reductions in irradiance significantly increased Chl a and Chl b contents and decreased Chl a/b ratios. Chloroplast ultrastructure generally displayed the best development in leaves subjected to 30% irradiance. Under 50% irradiance, leaf protein content remained relatively stable during the first 20 days of treatment, and then increased rapidly. The highest peroxidase and superoxide dismutase levels, and the lowest catalase activities, were observed in plants subjected to the 50% irradiance treatment. Soluble sugar and malondialdehyde contents were positively correlated with irradiance levels. Modulation of chloroplast development, accomplished by increasing the number of thylakoids and grana containing photosynthetic pigments, is an important shade tolerance mechanism in A. roxburghii. PMID:24516523

  18. A novel ammonia-oxidizing archaeon from wastewater treatment plant: Its enrichment, physiological and genomic characteristics.

    PubMed

    Li, Yuyang; Ding, Kun; Wen, Xianghua; Zhang, Bing; Shen, Bo; Yang, Yunfeng

    2016-01-01

    Ammonia-oxidizing archaea (AOA) are recently found to participate in the ammonia removal processes in wastewater treatment plants (WWTPs), similar to their bacterial counterparts. However, due to lack of cultivated AOA strains from WWTPs, their functions and contributions in these systems remain unclear. Here we report a novel AOA strain SAT1 enriched from activated sludge, with its physiological and genomic characteristics investigated. The maximal 16S rRNA gene similarity between SAT1 and other reported AOA strain is 96% (with "Ca. Nitrosotenuis chungbukensis"), and it is affiliated with Wastewater Cluster B (WWC-B) based on amoA gene phylogeny, a cluster within group I.1a and specific for activated sludge. Our strain is autotrophic, mesophilic (25 °C-33 °C) and neutrophilic (pH 5.0-7.0). Its genome size is 1.62 Mb, with a large fragment inversion (accounted for 68% genomic size) inside. The strain could not utilize urea due to truncation of the urea transporter gene. The lack of the pathways to synthesize usual compatible solutes makes it intolerant to high salinity (>0.03%), but could adapt to low salinity (0.005%) environments. This adaptation, together with possibly enhanced cell-biofilm attachment ability, makes it suitable for WWTPs environment. We propose the name "Candidatus Nitrosotenuis cloacae" for the strain SAT1. PMID:27030530

  19. Physiological, anatomical and transcriptional alterations in a rice mutant leading to enhanced water stress tolerance.

    PubMed

    Lima, John Milton; Nath, Manoj; Dokku, Prasad; Raman, K V; Kulkarni, K P; Vishwakarma, C; Sahoo, S P; Mohapatra, U B; Mithra, S V Amitha; Chinnusamy, V; Robin, S; Sarla, N; Seshashayee, M; Singh, K; Singh, A K; Singh, N K; Sharma, R P; Mohapatra, T

    2015-01-01

    Water stress is one of the most severe constraints to crop productivity. Plants display a variety of physiological and biochemical responses both at the cellular and whole organism level upon sensing water stress. Leaf rolling, stomatal closure, deeper root penetration, higher relative water content (RWC) and better osmotic adjustment are some of the mechanisms that plants employ to overcome water stress. In the current study, we report a mutant, enhanced water stress tolerant1 (ewst1) with enhanced water stress tolerance, identified from the ethyl methanesulfonate-induced mutant population of rice variety Nagina22 by field screening followed by withdrawal of irrigation in pots and hydroponics (PEG 6000). Though ewst1 was morphologically similar to the wild type (WT) for 35 of the 38 morphological descriptors (except chalky endosperm/expression of white core, decorticated grain colour and grain weight), it showed enhanced germination in polyethylene glycol-infused medium. It exhibited increase in maximum root length without any significant changes in its root weight, root volume and total root number on crown when compared with the WT under stress in PVC tube experiment. It also showed better performance for various physiological parameters such as RWC, cell membrane stability and chlorophyll concentration upon water stress in a pot experiment. Root anatomy and stomatal microscopic studies revealed changes in the number of xylem and phloem cells, size of central meta-xylem and number of closed stomata in ewst1. Comparative genome-wide transcriptome analysis identified genes related to exocytosis, secondary metabolites, tryptophan biosynthesis, protein phosphorylation and other signalling pathways to be playing a role in enhanced response to water stress in ewst1. The possible involvement of a candidate gene with respect to the observed morpho-physiological and transcriptional changes and its role in stress tolerance are discussed. The mutant identified and

  20. Physiological, anatomical and transcriptional alterations in a rice mutant leading to enhanced water stress tolerance

    PubMed Central

    Lima, John Milton; Nath, Manoj; Dokku, Prasad; Raman, K. V.; Kulkarni, K. P.; Vishwakarma, C.; Sahoo, S. P.; Mohapatra, U. B.; Mithra, S. V. Amitha; Chinnusamy, V.; Robin, S.; Sarla, N.; Seshashayee, M.; Singh, K.; Singh, A. K.; Singh, N. K.; Sharma, R. P.; Mohapatra, T.

    2015-01-01

    Water stress is one of the most severe constraints to crop productivity. Plants display a variety of physiological and biochemical responses both at the cellular and whole organism level upon sensing water stress. Leaf rolling, stomatal closure, deeper root penetration, higher relative water content (RWC) and better osmotic adjustment are some of the mechanisms that plants employ to overcome water stress. In the current study, we report a mutant, enhanced water stress tolerant1 (ewst1) with enhanced water stress tolerance, identified from the ethyl methanesulfonate-induced mutant population of rice variety Nagina22 by field screening followed by withdrawal of irrigation in pots and hydroponics (PEG 6000). Though ewst1 was morphologically similar to the wild type (WT) for 35 of the 38 morphological descriptors (except chalky endosperm/expression of white core, decorticated grain colour and grain weight), it showed enhanced germination in polyethylene glycol-infused medium. It exhibited increase in maximum root length without any significant changes in its root weight, root volume and total root number on crown when compared with the WT under stress in PVC tube experiment. It also showed better performance for various physiological parameters such as RWC, cell membrane stability and chlorophyll concentration upon water stress in a pot experiment. Root anatomy and stomatal microscopic studies revealed changes in the number of xylem and phloem cells, size of central meta-xylem and number of closed stomata in ewst1. Comparative genome-wide transcriptome analysis identified genes related to exocytosis, secondary metabolites, tryptophan biosynthesis, protein phosphorylation and other signalling pathways to be playing a role in enhanced response to water stress in ewst1. The possible involvement of a candidate gene with respect to the observed morpho-physiological and transcriptional changes and its role in stress tolerance are discussed. The mutant identified and

  1. Physiological and growth responses to water deficit in the bioenergy crop Miscanthus x giganteus

    PubMed Central

    Ings, Jennifer; Mur, Luis A. J.; Robson, Paul R. H.; Bosch, Maurice

    2013-01-01

    High yielding perennial biomass crops of the species Miscanthus are widely recognized as one of the most promising lignocellulosic feedstocks for the production of bioenergy and bioproducts. Miscanthus is a C4 grass and thus has relatively high water use efficiency. Cultivated Miscanthus comprises primarily of a single clone, Miscanthus x giganteus, a sterile hybrid between M. sacchariflorus and M. sinensis. M. x giganteus is high yielding and expresses desirable combinations of many traits present in the two parental species types; however, it responds poorly to low water availability. To identify the physiological basis of the response to water stress in M. x giganteus and to identify potential targets for breeding improvements we characterized the physiological responses to water-deficit stress in a pot experiment. The experiment has provided valuable insights into the temporal aspects of drought-induced responses of M. x giganteus. Withholding water resulted in marked changes in plant physiology with growth-associated traits among the first affected, the most rapid response being a decline in the rate of stem elongation. A reduction in photosynthetic performance was among the second set of changes observed; indicated by a decrease in stomatal conductance followed by decreases in chlorophyll fluorescence and chlorophyll content. Measures reflecting the plant water status were among the last affected by the drought treatment. Metabolite analysis indicated that proline was a drought stress marker in M. x giganteus, metabolites in the proline synthesis pathway were more abundant when stomatal conductance decreased and dry weight accumulation ceased. The outcomes of this study in terms of drought-induced physiological changes, accompanied by a proof-of-concept metabolomics investigation, provide a platform for identifying targets for improved drought-tolerance of the Miscanthus bioenergy crop. PMID:24324474

  2. [Effects of sodium naphthalene acetate on growth and physiological characteristics of tomato seedlings under suboptimal temperature and light condition].

    PubMed

    Guo, Yun-na; Li, Yan-su; He, Chao-xing; Yu, Xian-chang

    2015-10-01

    Taking tomato 'Zhongza 105' as test material, the influences of sodium naphthalene acetate (SNA) on growth and physiological characteristics of tomato seedlings under suboptimal temperature and light condition were investigated. The results showed that the dry mass, vigorous seedling index, root activity, total nitrogen content, net photosynthesis rate (Pn) of tomato seedlings were significantly decreased by suboptimum temperature and light treatment. In addition, the catalase activity and zeatin riboside (ZR) concentration were also reduced. However, the superoxide dismutase, peroxidase activity and the content of abscisic acid (ABA) were increased. Compared with treatment of the same volume distilled water on tomato seedlings under suboptimum temperature and light condition, the dry mass of whole plant and vigorous seedling index of tomato seedlings were significantly increased by 16.4% and 22.9%, as the total N contents in roots and leaves and Pn were also increased by 8.5%, 28.5%and 37.0%, respectively, with the treatment of root application of 10 mg . L-1 SNA. Besides protective enzyme activity and the root activity were improved, the indole acetic acid (IAA) and ZR concentration of tomato were raised, and ABA concentration was reduced. The results indicated that root application of certain concentration of SNA could promote the growth of tomato seedlings by increasing the tomato root activity, protective enzymes activity, Pn and regulating endogenous hormone concentration under suboptimum temperature and light condition. PMID:26995913

  3. Physiological Characteristics Underlying the Distribution Patterns of Luminous Bacteria in the Mediterranean Sea and the Gulf of Elat

    PubMed Central

    Shilo, M.; Yetinson, T.

    1979-01-01

    Physiological characteristics of luminous bacteria isolated from the Mediterranean and Gulf of Elat were compared to determine their relationship to the specific seasonal and geographic distribution patterns of these bacteria. The effects of temperature on growth rate and yield, relative sensitivity to photooxidation, resistance to high salt concentration (8%), and ability to grow in nutrient-poor conditions appear to control these patterns. The winter appearance of Photobacterium fischeri and the succession of winter and summer types of Beneckea harveyi in the eastern Mediterranean are explained by different temperature requirements for growth. Sensitivity to photooxidation explains the disappearance of P. leiognathi, present in the main body of the Gulf of Elat throughout the year, from the shallow coastal strip. B. harveyi is present in this coastal strip which is higher in nutrients and in productivity than the open waters. Competition experiments between B. harveyi and P. leiognathi in batch and continuous culture indicate that the oligotrophic P. leiognathi is outcompeted by B. harveyi in rich and even in relatively poor media. The distribution pattern found in the Bardawil hypersaline lagoon is explained by selection of salinity-resistant mutants of B. harveyi from the Mediterranean Sea. PMID:16345442

  4. Growth and Physiological Responses to Water Depths in Carex schmidtii Meinsh

    PubMed Central

    Yan, Hong; Liu, Ruiquan; Liu, Zinan; Wang, Xue; Luo, Wenbo; Sheng, Lianxi

    2015-01-01

    A greenhouse experiment was performed to investigate growth and physiological responses to water depth in completely submerged condition of a wetland plant Carex schmidtii Meinsh., one of the dominant species in the Longwan Crater Lake wetlands (China). Growth and physiological responses of C. schmidtii were investigated by growing under control (non-submerged) and three submerged conditions (5 cm, 15 cm and 25 cm water level). Total biomass was highest in control, intermediate in 5 cm treatment and lowest in the other two submerged treatments. Water depth prominently affected the first-order lateral root to main root mass ratio. Alcohol dehydrogenase (ADH) activity decreased but malondialdehyde (MDA) content increased as water depth increased. The starch contents showed no differences among the various treatments at the end of the experiment. However, soluble sugar contents were highest in control, intermediate in 5 cm and 15 cm treatments and lowest in 25 cm treatment. Our data suggest that submergence depth affected some aspects of growth and physiology of C. schmidtii, which can reduce anoxia damage not only through maintaining the non-elongation strategy in shoot part but also by adjusting biomass allocation to different root orders rather than adjusting root-shoot biomass allocation. PMID:26009895

  5. Comparative reproductive and physiological responses of northern bobwhite and scaled quail to water deprivation

    USGS Publications Warehouse

    Giuliano, W.M.; Patino, R.; Lutz, R.S.

    1998-01-01

    We compared reproductive and physiological responses of captive female northern bobwhite (Colinus virginianus) and scaled quail (Callipepla squamata) under control and water deprivation conditions. Scaled quail required less food and water to reproduce successfully under control conditions than northern bobwhite. Additionally, in scaled quail, serum osmolality levels and kidney mass were unaffected by water deprivation, whereas in northern bobwhite, serum osmolality levels increased and kidney mass declined. This finding indicates that scaled quail may have osmoregulatory abilities superior to those of northern bobwhite. Under control conditions, northern bobwhite gained more body mass and produced more but smaller eggs than scaled quail. Under water deprivation conditions, northern bobwhite lost more body mass but had more laying bens with a higher rate of egg production than scaled quail. Our data suggest that northern bobwhite allocated more resources to reproduction than to body maintenance, while scaled quail apparently forego reproduction in favor of body maintenance during water deprivation conditions.

  6. Comparative community physiology: nonconvergence in water relations among three semi-arid shrub communities.

    PubMed

    Jacobsen, Anna L; Pratt, R Brandon; Davis, Stephen D; Ewers, Frank W

    2008-01-01

    Plant adaptations to the environment are limited, and therefore plants in similar environments may display similar functional and physiological traits, a pattern termed functional convergence. Evidence was examined for functional convergence among 28 evergreen woody shrubs from three plant communities of the semi-arid winter rainfall region of southern California. Both leaf and water relations traits were examined, including seasonal stomatal conductance (gs), specific leaf area (SLA), leaf specific conductivity (Kl), seasonal water potential (Psi w), stem cavitation resistance (Psi 50), and xylem density. Species display community-specific suites of xylem and leaf traits consistent with different patterns of water use among communities, with coastal sage scrub species utilizing shallow pulses of water, Mojave Desert scrub species relying on deeper water reserves, and chaparral species utilizing both shallow and deep moisture reserves. Communities displayed similar degrees of water stress, with a community-level minimum Psi w (Psi wmin) of c. -4.6 Mpa, similar to other arid communities. Pooled across sites, there was a strong correlation between Psi wmin and xylem density, suggesting that these traits are broadly related and predictive of one another. This comparative community physiology approach may be useful in testing hypotheses of functional convergence across structurally similar semi-arid communities. PMID:18627498

  7. Physiologic responses to water immersion in man: A compendium of research

    NASA Technical Reports Server (NTRS)

    Kollias, J.; Vanderveer, D.; Dorchak, K. J.; Greenleaf, J. E.

    1976-01-01

    A total of 221 reports published through December 1973 in the area of physiologic responses to water immersion in man were summarized. The author's abstract or summary was used whenever possible. Otherwise, a detailed annotation was provided under the subheadings: (1) purpose, (2) procedures and methods, (3) results, and (4) conclusions. The annotations are in alphabetical order by first author; author and subject indexes are included. Additional references are provided in the selected bibliography.

  8. Assessing physiological responses of dune forest functional groups to changing water availability: from Tropics to Mediterranean.

    NASA Astrophysics Data System (ADS)

    Antunes, Cristina; Lo Cascio, Mauro; Correia, Otília; Vieira, Simone; Cruz Diaz Barradas, Maria; Zunzunegui, Maria; Ramos, Margarida; João Pereira, Maria; Máguas, Cristina

    2014-05-01

    Alterations in water availability are important to vegetation as can produce dramatic changes in plant communities, on physiological performance or survival of plant species. Particularly, groundwater lowering and surface water diversions will affect vulnerable coastal dune forests, ecosystems particularly sensitive to groundwater limitation. Reduction of water tables can prevent the plants from having access to one of their key water sources and inevitably affect groundwater-dependent species. The additional impact of drought due to climatic change on groundwater-dependent ecosystems has become of increasing concern since it aggravates groundwater reduction impacts with consequent uncertainties about how vegetation will respond over the short and long term. Sand dune plant communities encompass a diverse number of species that differ widely in root depth, tolerance to drought and capacity to shift between seasonal varying water sources. Plant functional groups may be affected by water distribution and availability differently. The high ecological diversity of sand dune forests, characterized by sandy soils, well or poorly drained, poor in nutrients and with different levels of salinity, can occur in different climatic regions of the globe. Such is the case of Tropical, Meso-mediterranean and Mediterranean areas, where future climate change is predicted to change water availability. Analyses of the relative natural abundances of stable isotopes of carbon (13C/12C) and oxygen (18O/16O) have been used across a wide range of scales, contributing to our understanding of plant ecology and interactions. This approach can show important temporal and spatial changes in utilization of different water sources by vegetation. Accordingly, the core idea of this work is to evaluate, along a climatic gradient, the responses and capacity of different coastal plant communities to adapt to changing water availability. This large-climatic-scale study, covering Brazil, Portugal and

  9. Physiological response of the cold-water coral Desmophyllum dianthus to thermal stress and ocean acidification.

    PubMed

    Gori, Andrea; Ferrier-Pagès, Christine; Hennige, Sebastian J; Murray, Fiona; Rottier, Cécile; Wicks, Laura C; Roberts, J Murray

    2016-01-01

    Rising temperatures and ocean acidification driven by anthropogenic carbon emissions threaten both tropical and temperate corals. However, the synergistic effect of these stressors on coral physiology is still poorly understood, in particular for cold-water corals. This study assessed changes in key physiological parameters (calcification, respiration and ammonium excretion) of the widespread cold-water coral Desmophyllum dianthus maintained for ∼8 months at two temperatures (ambient 12 °C and elevated 15 °C) and two pCO2 conditions (ambient 390 ppm and elevated 750 ppm). At ambient temperatures no change in instantaneous calcification, respiration or ammonium excretion rates was observed at either pCO2 levels. Conversely, elevated temperature (15 °C) significantly reduced calcification rates, and combined elevated temperature and pCO2 significantly reduced respiration rates. Changes in the ratio of respired oxygen to excreted nitrogen (O:N), which provides information on the main sources of energy being metabolized, indicated a shift from mixed use of protein and carbohydrate/lipid as metabolic substrates under control conditions, to less efficient protein-dominated catabolism under both stressors. Overall, this study shows that the physiology of D. dianthus is more sensitive to thermal than pCO2 stress, and that the predicted combination of rising temperatures and ocean acidification in the coming decades may severely impact this cold-water coral species. PMID:26855864

  10. Physiological response of the cold-water coral Desmophyllum dianthus to thermal stress and ocean acidification

    PubMed Central

    Ferrier-Pagès, Christine; Hennige, Sebastian J.; Murray, Fiona; Rottier, Cécile; Wicks, Laura C.; Roberts, J. Murray

    2016-01-01

    Rising temperatures and ocean acidification driven by anthropogenic carbon emissions threaten both tropical and temperate corals. However, the synergistic effect of these stressors on coral physiology is still poorly understood, in particular for cold-water corals. This study assessed changes in key physiological parameters (calcification, respiration and ammonium excretion) of the widespread cold-water coral Desmophyllum dianthus maintained for ∼8 months at two temperatures (ambient 12 °C and elevated 15 °C) and two pCO2 conditions (ambient 390 ppm and elevated 750 ppm). At ambient temperatures no change in instantaneous calcification, respiration or ammonium excretion rates was observed at either pCO2 levels. Conversely, elevated temperature (15 °C) significantly reduced calcification rates, and combined elevated temperature and pCO2 significantly reduced respiration rates. Changes in the ratio of respired oxygen to excreted nitrogen (O:N), which provides information on the main sources of energy being metabolized, indicated a shift from mixed use of protein and carbohydrate/lipid as metabolic substrates under control conditions, to less efficient protein-dominated catabolism under both stressors. Overall, this study shows that the physiology of D. dianthus is more sensitive to thermal than pCO2 stress, and that the predicted combination of rising temperatures and ocean acidification in the coming decades may severely impact this cold-water coral species. PMID:26855864

  11. Highly aligned lipid membrane systems in the physiologically relevant "excess water" condition.

    PubMed Central

    Katsaras, J

    1997-01-01

    The "excess water" condition in biologically relevant systems is met when a membrane mesophase coexists with excess bulk water. Further addition of water to such a system results in no change to any of the system's physical properties (e.g., transition temperature, repeat spacing, and structural mesophases). Moreover, because biological membranes are anisotropic systems, many of their properties are best studied using aligned samples. Although model membrane systems are routinely aligned, they have traditionally been hydrated with water vapor. It is well known that membranes exposed to water vapor at 100% humidity do not imbibe the same quantity of water as a sample in contact with liquid water. As such, membranes that have been hydrated with water vapor have physical properties different from those of membranes dispersed in water. Because of this shortcoming, aligned membranes have not been utilized to their full potential. Here we present a novel and simple method of aligning model membrane systems under conditions of excess water, which will make possible, for the first time, a variety of techniques (e.g., neutron and x-ray diffraction, nuclear magnetic resonance, electron spin resonance, attenuated total reflection infrared spectroscopy, etc.) for studying such systems under physiologically relevant conditions. In addition, when dealing with samples of limited availability, the system allows for the conditions (buffer pH and ionic strength) to be altered without any effect on the sample's alignment. Images FIGURE 1 PMID:9414206

  12. Effects of salt stress on eco-physiological characteristics in Robinia pseudoacacia based on salt-soil rhizosphere.

    PubMed

    Mao, Peili; Zhang, Yujuan; Cao, Banghua; Guo, Longmei; Shao, Hongbo; Cao, Zhenyu; Jiang, Qiankun; Wang, Xuan

    2016-10-15

    Robinia pseudoacacia is the main arbor species in the coastal saline-alkali area of the Yellow River Delta. Because most studies focus on the aboveground parts, detailed information regarding root functioning under salinity is scare. Root traits of seedlings of R. pseudoacacia including morphological, physiological and growth properties under four salinity levels (CK, 1‰, 3‰ and 5‰ NaCl) were studied by the pot experiments to better understand their functions and relationships with the shoots. The results showed that seedling biomass decreased by the reduction of root, stem and leaf biomass with the increase of salinity levels. With increasing salinity levels, total root length (TRL) and total root surface area (TRSA) decreased, whereas specific root length (SRL) and specific root area (SRA) increased. Salt stress decreased root activity (RA) and the maximum net photosynthetic rate (Amax) and increased the water saturation deficit (WSD) significantly in the body. Correlation analyses showed significantly correlations between root morphological and physiological parameters and seedling biomass and shoot physiological indexes. R. pseudoacacia seedlings could adapt to 1‰ salinity by regulating the root morphology and physiology, but failed in 5‰ salinity. How to adjust the water status in the body with decreasing water uptake by roots was an important way for R. pseudoacacia seedlings to adapt to the salt stress. PMID:27289394

  13. Response of the physiological parameters of mango fruit (transpiration, water relations and antioxidant system) to its light and temperature environment.

    PubMed

    Léchaudel, Mathieu; Lopez-Lauri, Félicie; Vidal, Véronique; Sallanon, Huguette; Joas, Jacques

    2013-04-15

    Depending on the position of the fruit in the tree, mango fruit may be exposed to high temperature and intense light conditions that may lead to metabolic and physiological disorders and affect yield and quality. The present study aimed to determine how mango fruit adapted its functioning in terms of fruit water relations, epicarp characteristics and the antioxidant defence system in peel, to environmental conditions. The effect of contrasted temperature and light conditions was evaluated under natural solar radiation and temperature by comparing well-exposed and shaded fruit at three stages of fruit development. The sun-exposed and shaded peels of the two sides of the well-exposed fruit were also compared. Depending on fruit position within the canopy and on the side of a well-exposed fruit, the temperature gradient over a day affected fruit characteristics such as transpiration, as revealed by the water potential gradient as a function of the treatments, and led to a significant decrease in water conductance for well-exposed fruits compared to fruits within the canopy. Changes in cuticle thickness according to fruit position were consistent with those of fruit water conductance. Osmotic potential was also affected by climatic environment and harvest stage. Environmental conditions that induced water stress and greater light exposure, like on the sunny side of well-exposed fruit, increased the hydrogen peroxide, malondialdehyde and total and reduced ascorbate contents, as well as SOD, APX and MDHAR activities, regardless of the maturity stage. The lowest values were measured in the peel of the shaded fruit, that of the shaded side of well-exposed fruit being intermediate. Mango fruits exposed to water-stress-induced conditions during growth adapt their functioning by reducing their transpiration. Moreover, oxidative stress was limited as a consequence of the increase in antioxidant content and enzyme activities. This adaptive response of mango fruit to its

  14. Physiological relationships of the early posthatch performance of broilers to their embryo and eggshell characteristics.

    PubMed

    Pulikanti, R; Peebles, E D; Zhai, W; Bennett, L W; Gerard, P D

    2012-07-01

    Relationships between physiological parameters of early posthatch chicks with their corresponding egg and embryo parameters were examined in progeny of young broiler breeders. Four hundred and 80 broiler hatching eggs that were obtained from a 29-wk-old Ross 308 breeder flock were incubated on 8 replicate tray levels of an incubator until hatch. Between 10.5 and 18.5 d of incubation, internal (T(emb)) and external (T(ext)) egg temperatures were recorded twice daily using temperature transponders. Beginning at 18.5 d, the eggs were individually monitored for hatch every 12 h. Average T(emb), T(ext), and average daily incubational egg weight loss (EWL) for the 10.5- to 18.5-d incubation period were used to calculate eggshell water vapor conductance (G(H2O)), specific G(H2O) (g(H2O); G(H2O) adjusted to 100 g of set egg weight basis), and a G(H2O) constant (K(H2O)) for each egg. Chicks were grown out for 10 d in pens of a single battery brooder. In each pen, on d 3 posthatch, carcasses, yolk sac, liver, and pipping muscle samples were collected from at least 2 chicks that hatched from eggs implanted with transponders for determination of their relative weights and moisture concentrations. Livers and pipping muscles were also analyzed for glucose, glycogen, fat, and protein concentrations. Yolk sac weight as a percentage of chick BW (YW) and its moisture concentration (YSM) were positively correlated with T(emb). Egg g(H2O) was positively correlated with chick carcass moisture concentration and its relative weight as a percentage of set egg weight, but it was negatively correlated with YW. The positive functional relationship between T(emb) and incubation length may be mediated via their common positive relationships to YSM. A negative correlation was observed between percentage EWL and relative BW on d 0 and 0.5 posthatch for chicks hatched from unimplanted eggs. The results suggest that a higher g(H2O) results in an increased metabolism of the broiler embryo, which

  15. Effects of abiotic stress on physiological plasticity and water use of Setaria viridis (L.).

    PubMed

    Saha, Prasenjit; Sade, Nir; Arzani, Ahmad; Rubio Wilhelmi, Maria Del Mar; Coe, Kevin M; Li, Bosheng; Blumwald, Eduardo

    2016-10-01

    The emerging model Setaria viridis with its C4 photosynthesis and adaptation to hot and dry locations is a promising system to investigate water use and abiotic stress tolerance. We investigated the physiological plasticity of six S. viridis natural accessions that originated from different regions of the world under normal conditions and conditions of water-deficit stress and high temperatures. Accessions Zha-1, A10.1 and Ula-1 showed significantly higher leaf water potential (Ψleaf), photosynthesis (A), transpiration (E), and stomatal conductance (gs) rates compared to Ast-1, Aba-1 and Sha-1 when grown under stress conditions. Expression analysis of genes associated with C4 photosynthesis, aquaporins, ABA biosynthesis and signaling including genes involved in stress revealed an increased sensitivity of Ast-1, Aba-1 and Sha-1 to stresses. Correlation analysis of gene expression data with physiological and biochemical changes characterized A10.1 and Ast-1 as two extreme tolerant and sensitive accessions originated from United States and Azerbaijan under water-deficit and heat stress, respectively. Although preliminary, our study demonstrated the plasticity of S. viridis accessions under stress, and allows the identification of tolerant and sensitive accessions that could be use to study the mechanisms associated with stress tolerance and to characterize of the regulatory networks involved in C4 grasses. PMID:27593471

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

    PubMed

    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 < 0.005). Significant decreases in skin temperature, sweat rate, heart rate, and heat storage was also noted in the HI vs. the CO trials. Tolerance time in the HI exposure were longer than in the CO exposure (only 12 subjects in the CO trial endured the entire heat exposure session, as opposed to all 17 subjects in the HI group). It is concluded that hand 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. PMID:18478254

  17. Characteristics of metabolism during prolonged water immersion.

    PubMed

    Tigranyan, R A

    1975-01-01

    The effect on the organism of a 12-day stay in a water immersion medium (head on the water surface) was studied on 10 subjects. The condition of the metabolic processes in the subjects was judged from the investigation of the parameters of protein and carbohydrate metabolism, acid-base equilibrium, the activity of a number of enzymes and steroid hormones. The venous blood and diurnal urine served as the material for conducting the corresponding biochemical determinations. The stay in an immersion medium is accompanied by a significant increase in the content of residual nitrogen in the blood, by a reduction of the creatinine content in the blood and by an increase of the creatine content of the blood with the simultaneous increase of the excretion of creatinine and creatine with the urine, by a significant increase of the glucose and lactate content in the blood, by the development of acidosis of a respiratory and metabolic character, as well as by a significant increase of the activity of creatine phosphokinase and the isoenzyme fraction of lactate dehydrogenase3. In all the subjects, an expressed intensification of the glucocorticoid and androgenic functions of the adrenal cortex is noted during the experimental period. PMID:11887912

  18. Eco-Physiological Responses of Dominant Species to Watering in a Natural Grassland Community on the Semi-Arid Loess Plateau of China.

    PubMed

    Niu, Furong; Duan, Dongping; Chen, Ji; Xiong, Peifeng; Zhang, He; Wang, Zhi; Xu, Bingcheng

    2016-01-01

    Altered precipitation regimes significantly affect ecosystem structure and function in arid and semi-arid regions. In order to investigate effects of precipitation changes on natural grassland community in the semi-arid Loess Plateau, the current research examined eco-physiological characteristics of two co-dominant species (i.e., Bothriochloa ischaemum and Lespedeza davurica) and community composition following two watering instances (i.e., precipitation pulses, July and August, 2011, respectively) in a natural grassland community. Results showed that the photosynthetic rate, transpiration rate, stomatal conductance and intercellular CO2 concentration rapidly increased on the first to third day following watering in both species, and both months. Under watering treatments, the maximum net photosynthetic rates appeared on the second to third day after watering, which increased 30-80% in B. ischaemum and 40-50% in L. davurica compared with non-watering treatments, respectively. Leaf water use efficiency kept stable or initially decreased in both species under watering treatments. Watering in July produced more promoting effects on grass photosynthesis than in August, particularly in B. ischaemum. Community above-ground biomass at the end of the growing season increased after watering, although no significant changes in species diversity were observed. Our results indicated that timing and magnitude of watering could significantly affect plant eco-physiological processes, and there were species-specific responses in B. ischaemum and L. davurica. Pulsed watering increased community productivity, while did not significantly alter community composition after one growing season. The outcomes of this study highlight eco-physiological traits in dominant species may playing important roles in reshaping community composition under altered precipitation regimes. PMID:27242864

  19. Eco-Physiological Responses of Dominant Species to Watering in a Natural Grassland Community on the Semi-Arid Loess Plateau of China

    PubMed Central

    Niu, Furong; Duan, Dongping; Chen, Ji; Xiong, Peifeng; Zhang, He; Wang, Zhi; Xu, Bingcheng

    2016-01-01

    Altered precipitation regimes significantly affect ecosystem structure and function in arid and semi-arid regions. In order to investigate effects of precipitation changes on natural grassland community in the semi-arid Loess Plateau, the current research examined eco-physiological characteristics of two co-dominant species (i.e., Bothriochloa ischaemum and Lespedeza davurica) and community composition following two watering instances (i.e., precipitation pulses, July and August, 2011, respectively) in a natural grassland community. Results showed that the photosynthetic rate, transpiration rate, stomatal conductance and intercellular CO2 concentration rapidly increased on the first to third day following watering in both species, and both months. Under watering treatments, the maximum net photosynthetic rates appeared on the second to third day after watering, which increased 30–80% in B. ischaemum and 40–50% in L. davurica compared with non-watering treatments, respectively. Leaf water use efficiency kept stable or initially decreased in both species under watering treatments. Watering in July produced more promoting effects on grass photosynthesis than in August, particularly in B. ischaemum. Community above-ground biomass at the end of the growing season increased after watering, although no significant changes in species diversity were observed. Our results indicated that timing and magnitude of watering could significantly affect plant eco-physiological processes, and there were species-specific responses in B. ischaemum and L. davurica. Pulsed watering increased community productivity, while did not significantly alter community composition after one growing season. The outcomes of this study highlight eco-physiological traits in dominant species may playing important roles in reshaping community composition under altered precipitation regimes. PMID:27242864

  20. Spectral reflectance and radiance characteristics of water pollutants

    NASA Technical Reports Server (NTRS)

    Wezernak, C. T.; Turner, R. E.; Lyzenga, D. R.

    1976-01-01

    Spectral reflectance characteristics of water pollutants and water bodies were compiled using the existing literature. Radiance calculations were performed at satellite altitude for selected illumination angles and atmospheric conditions. The work described in this report was limited to the reflective portion of the spectrum between 0.40 micrometer to 1.0 micrometer.

  1. Comparative morpho-physiological and biochemical responses of lentil and grass pea genotypes under water stress

    PubMed Central

    Talukdar, Dibyendu

    2013-01-01

    Background: Both lentil (Lens culinaris Medik.) and grass pea (Lathyrus sativus L.) in the family Fabaceae are two important cool-season food legumes, often experiencing water stress conditions during growth and maturity. Objective: The present study was undertaken to ascertain the response of these two crops under different water stress regimes. Materials and Methods: Different morpho-physiological and biochemical parameters were studied in a pot experiment under controlled environmental conditions. Along with control (proper irrigation, 0 stress), three sets of plants were subjected to mild (6 d), moderate (13 d) and severe (20 d) water stress by withholding irrigation at the appropriate time. Results: Compared with control, plant growth traits and seed yield components reduced significantly in both crops with increasing period of water stress, resulting in lowering of dry mass with more severe effect on lentil compared with grass pea. Foliar Relative Water Content (RWC) (%), K+/Na+ ratio, chlorophyll (chl) a, chl a/b ratio, stomatal conductance and net photosynthetic rate declined considerably in both crops under water stress. Leaf-free proline level increased significantly in both crops, but it decreased markedly in nodules of lentil and remained unchanged in grass pea. Nodulation was also affected due to water stress. The impairment in growth traits and physio-biochemical parameters under water stress was manifested in reduction of drought tolerance efficiency of both crops. Conclusion: Impact of water stress was more severe on lentil compared with grass pea, and modulation of growth traits signified necessity of a detailed strategy in breeding of food legumes under water stress. PMID:24082740

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

    PubMed

    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

  3. Anthropomorphic breast phantoms with physiological water, lipid, and hemoglobin content for near-infrared spectral tomography

    PubMed Central

    Michaelsen, Kelly E.; Krishnaswamy, Venkataramanan; Shenoy, Adele; Jordan, Emily; Pogue, Brian W.; Paulsen, Keith D.

    2014-01-01

    Abstract. Breast mimicking tissue optical phantoms with sufficient structural integrity to be deployed as stand-alone imaging targets are developed and successfully constructed with biologically relevant concentrations of water, lipid, and blood. The results show excellent material homogeneity and reproducibility with inter- and intraphantom variability of 3.5 and 3.8%, respectively, for water and lipid concentrations ranging from 15 to 85%. The phantoms were long-lasting and exhibited water and lipid fractions that were consistent to within 5% of their original content when measured 2 weeks after creation. A breast-shaped three-compartment model of adipose, fibroglandular, and malignant tissues was created with water content ranging from 30% for the adipose simulant to 80% for the tumor. Mean measured water content ranged from 30% in simulated adipose to 73% in simulated tumor with the higher water localized to the tumor-like material. This novel heterogeneous phantom design is composed of physiologically relevant concentrations of the major optical absorbers in the breast in the near-infrared wavelengths that should significantly improve imaging system characterization and optimization because the materials have stand-alone structural integrity and can be readily molded into the sizes and shapes of tissues commensurate with clinical breast imaging. PMID:24549438

  4. Characteristics of water infiltration in layered water repellent soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hydrophobic soil can influence soil water infiltration, but information regarding the impacts of different levels of hydrophobicity within a layered soil profile is limited. An infiltration study was conducted to determine the effects of different levels of hydrophobicity and the position of the hyd...

  5. Nonlinear Dynamic Characteristics of Oil-in-Water Emulsions

    NASA Astrophysics Data System (ADS)

    Yin, Zhaoqi; Han, Yunfeng; Ren, Yingyu; Yang, Qiuyi; Jin, Ningde

    2016-08-01

    In this article, the nonlinear dynamic characteristics of oil-in-water emulsions under the addition of surfactant were experimentally investigated. Firstly, based on the vertical upward oil-water two-phase flow experiment in 20 mm inner diameter (ID) testing pipe, dynamic response signals of oil-in-water emulsions were recorded using vertical multiple electrode array (VMEA) sensor. Afterwards, the recurrence plot (RP) algorithm and multi-scale weighted complexity entropy causality plane (MS-WCECP) were employed to analyse the nonlinear characteristics of the signals. The results show that the certainty is decreasing and the randomness is increasing with the increment of surfactant concentration. This article provides a novel method for revealing the nonlinear dynamic characteristics, complexity, and randomness of oil-in-water emulsions with experimental measurement signals.

  6. [Impacts of algal blooms accumulation on physiological ecology of water hyacinth].

    PubMed

    Wu, Ting-ting; Liu, Guo-feng; Han, Shi-qun; Zhou, Qing; Tang, Wan-ying

    2015-01-01

    Blue-green algae bloom will consume plenty of dissolved oxygen in water, which affects the growth of aquatic plants. The effects of water hyacinth growth and physiological response changes under 25 degrees C, 5 different concentrations of cyanobacteria gathered were studied and which would provide a theoretical basis to mitigate adverse impacts and improve water purification effect. The results showed that water quality indexes including dissolved oxygen (DO), pH dropped in algae density below 60 g x L(-1), with the increase of algae density. And the level of oxidation-reduction potential dropped to about 100 mV. The removal rates of TN, TP and COD were 58%-78%, 43%-68% and 59%-73%, leaf soluble protein, soluble sugar, MDA contents increased, respectively; and the MDA content became higher with the increase of algae density. It indicated that the water hyacinth could adapt to the adversity condition as algae density less than 60 g x L(-1). While algae density above 60 g x L(-1), water quality indexes significantly decreased, respectively and the water was in hypoxia or anoxia conditions. Plant leaves soluble sugar contents had a change trend of low-high-low. It indicated that the removal rates of TN, TP decreased with the increase of algae density and water hyacinth had irreversible stress. Plant root length, total length, fresh weight in different treatments, increased compared with the beginning of the experiment, the increase of root length, total length and fresh weight were 0.29-2.44 times, 0.41-0.76 times and 0.9-1.43 times. The increase of root length, total length decreased with the increase of algae density. According to the results, the cyanobacteria should avoid of excessive accumulation as using the floating plant to purify the water. PMID:25898654

  7. Physiological effects of sublethal levels of acid water on three species of fishes

    SciTech Connect

    Pegg, W.J.

    1984-01-01

    Static toxicity tests revealed the need to assess the effect of acid mine water using some procedure that would gradually increase the concentration of acidity over a period of time. A relatively long-term (2-5 days) experiment involving the devlopment of a sublethal acid treatment gradient was chosen as potentially being the most representative of natural environments which are periodically subjected to changing inputs from coal mine drainage. Since respiratory change is an indication of physiological stress, the measurement of oxygen consumption rate was chosen as the major variable representing the effect of acid waters on fishes. Bluegill sunfish Lepomes macrochirus Rafinesque, pumpkinseed sunfish, Lepomis gibbosus (Linnaeus), and brown bullhead, Ictalurus nebulosus (LeSueur) were collected from the Monongahela River and backwater areas in the region of Morgantown, West Virginia. The sublethal acid water treatments decreased the oxygen consumption rates for brown bullhead and bluegill sunfish, while increasing the oxygen consumption rate for pumpkinseed sunfish. Further, the rhythms of the oxygen consumption rates were generally modified in both frequency and amplitude as a result of exposure to acid water. Acid water treatments also caused negative phase shifts in oxygen consumption rate for brown bullhead sand bluegill sunfish, while positive phase shifts occurred for pumpkinseed sunfish.

  8. Pros and Cons of Using Water Immersion to Simulate Physiological Responses to Microgravity

    NASA Technical Reports Server (NTRS)

    Greenleaf, J. E.; Tomko, David L. (Technical Monitor)

    1995-01-01

    Head-out water immersion (HOI) has been employed as a remedial treatment for various ills and ailments for many millennia, and total body immersion even longer as protective encapsulation for the mammalian fetus. Two discrete differences between stimuli induced by true microgravity (10(exp -4) g) and HOI are readily apparent. External water pressure on the skin and accompanying negative pressure breathing cause blood to shift headward. Secondly, the gravitational force is ever present during immersion and microgravity, but its effect is essentially neutralized during Earth orbital flight. Thus, the physiological responses to immersion should not be expected to match those during microgravity. Immersion has been used mainly to study and understand kidney function and associated cardiovascular responses for control of body fluid volume and osmotic content, with some application to and simulation of microgravity responses. There is a plethora of data from human HOI studies, but relatively few controlled data from microgravity studies. In general, it appears that physiological responses occur more quickly with water immersion than in microgravity, but this may be due to less rigorous control (voluntary and involuntary) of the preflight state of crew members. The central venous pressure-vasopressin (Gauer-Henry) reflex control for fluid balance may not be of prime importance in microgravity. Gross functions such as reduced body weight and water, level of hypovolemia, decreased isokinetic strength, and lower nitrogen balance found during immersion are qualitatively similar in microgravity, but the mechanisms controlling these and other functions are, for the most part, unclear. Only acquisition of data from well-controlled microgravity experiments will resolve this discrepancy.

  9. Short communication: Characteristics of student success in an undergraduate physiology and anatomy course.

    PubMed

    Gwazdauskas, F C; McGilliard, M L; Corl, B A

    2014-10-01

    Several factors affect the success of students in college classes. The objective of this research was to determine what factors affect success of undergraduate students in an anatomy and physiology class. Data were collected from 602 students enrolled in the Agriculture and Life Sciences (ALS) 2304 Animal Physiology and Anatomy course from 2005 through 2012. The data set included 476 females (79.1%) and 126 males (20.9%). Time to complete exams was recorded for each student. For statistical analyses, students' majors were animal and poultry sciences (APSC), agricultural sciences, biochemistry, biological sciences, dairy science, and "other," which combined all other majors. All analyses were completed using the GLIMMIX procedure of SAS (SAS Institute Inc., Cary, NC). Gender, major, matriculation year, major by year interaction, gender by year interaction, and time to complete the exam affected final course grade. The significant gender effect was manifested in the final grade percentage of 75.9 ± 0.4 for female students compared with 72.3 ± 0.6 for male students. Junior males had final course grades comparable with those of females, but sophomore and senior males had lower final course grades than other combinations. Biology majors had a final grade of 82.4 ± 0.6 and this grade was greater than all other majors. Students classified as "other" had a final score of 74.4 ± 0.8, which was greater than agricultural science majors (69.5 ± 0.9). The APSC grade (72.6 ± 0.5) was higher than the agricultural science majors. Junior students had significantly greater final grades (76.1 ± 0.5) than sophomores (73.3 ± 0.6) and seniors (72.9 ± 0.9). All biology students had greater final grades than all other majors, but biochemistry juniors had greater final course grades than APSC, agricultural science, and dairy science juniors. "Other" seniors had greater final course grades than agricultural science seniors. The regression for time to complete the exam was

  10. The effect of lichen-dominated biological soil crusts on growth and physiological characteristics of three plant species in a temperate desert of northwest China.

    PubMed

    Zhuang, W W; Serpe, M; Zhang, Y M

    2015-11-01

    Biocrusts (biological soil crusts) cover open spaces between vascular plants in most arid and semi-arid areas. Information on effects of biocrusts on seedling growth is controversial, and there is little information on their effects on plant growth and physiology. We examined impacts of biocrusts on growth and physiological characteristics of three habitat-typical plants, Erodium oxyrhynchum, Alyssum linifolium and Hyalea pulchella, growing in the Gurbantunggut Desert, northwest China. The influence of biocrusts on plant biomass, leaf area, leaf relative water content, photosynthesis, maximum quantum efficiency of PSII (F(v)/F(m)), chlorophyll, osmotic solutes (soluble sugars, protein, proline) and antioxidant enzymes (superoxide dismutase, catalase, peroxidase) was investigated on sites with or without biocrust cover. Biomass, leaf area, leaf water content, photosynthesis, F(v)/F(m) and chlorophyll content in crusted soils were higher than in uncrusted soils during early growth and lower later in the growth period. Soluble sugars, proline and antioxidant enzyme activity were always higher in crusted than in uncrusted soils, while soluble protein content was always lower. These findings indicate that biocrusts have different effects on these three ephemeral species during growth in this desert, primarily via effects on soil moisture, and possibly on soil nutrients. The influence of biocrusts changes during plant development: in early plant growth, biocrusts had either positive or no effect on growth and physiological parameters. However, biocrusts tended to negatively influence plants during later growth. Our results provide insights to explain why previous studies have found different effects of biocrusts on vascular plant growth. PMID:26084731

  11. A Pig Model of the Preterm Neonate: Anthropometric and Physiological Characteristics

    PubMed Central

    Eiby, Yvonne A.; Wright, Layne L.; Kalanjati, Viskasari P.; Miller, Stephanie M.; Bjorkman, Stella T.; Keates, Helen L.; Lumbers, Eugenie R.; Colditz, Paul B.; Lingwood, Barbara E.

    2013-01-01

    Background Large animal models are an essential tool in the development of rationally-based new clinical therapies for preterm infants. We provide a description of the newborn pig as a model of the preterm neonate in terms of growth parameters, physiology and the requirement for intensive care over a range of gestational ages. Methods Twenty-nine litters of piglets (n = 298) were delivered by caesarean section at six timepoints during gestation from 91d to 113d (term = 115d). Two groups, at 91 and 97d gestation, also received maternal glucocorticoid treatment. At four of these timepoints, piglets (n = 79) were ventilated, sedated and monitored using standard neonatal intensive care techniques for up to 8 h in various experimental protocols. Results Body weight increased from mean 697 g (SD 193) at 91d gestation to 1331 g (SD 368) at 113d gestation. Piglets delivered at 97d gestation were able to be resuscitated and kept alive for at least 8 h on respiratory support after surfactant administration. Maternal glucocorticoid treatment 48 h and 24 h hours prior to delivery reduced the requirement for ventilator support and improved cardiovascular stability. Conclusion The pig provides a relevant model for the study of human preterm physiology and for investigation of novel therapies to improve outcomes. PMID:23874755

  12. Water sensor ppk28 modulates Drosophila lifespan and physiology through AKH signaling

    PubMed Central

    Waterson, Michael J.; Chung, Brian Y.; Harvanek, Zachary M.; Ostojic, Ivan; Alcedo, Joy; Pletcher, Scott D.

    2014-01-01

    Sensory perception modulates lifespan across taxa, presumably due to alterations in physiological homeostasis after central nervous system integration. The coordinating circuitry of this control, however, remains unknown. Here, we used the Drosophila melanogaster gustatory system to dissect one component of sensory regulation of aging. We found that loss of the critical water sensor, pickpocket 28 (ppk28), altered metabolic homeostasis to promote internal lipid and water stores and extended healthy lifespan. Additionally, loss of ppk28 increased neuronal glucagon-like adipokinetic hormone (AKH) signaling, and the AKH receptor was necessary for ppk28 mutant effects. Furthermore, activation of AKH-producing cells alone was sufficient to enhance longevity, suggesting that a perceived lack of water availability triggers a metabolic shift that promotes the production of metabolic water and increases lifespan via AKH signaling. This work provides an example of how discrete gustatory signals recruit nutrient-dependent endocrine systems to coordinate metabolic homeostasis, thereby influencing long-term health and aging. PMID:24821805

  13. Anatomy & Physiology

    MedlinePlus

    ... Central Nervous System Peripheral Nervous System Review Quiz Endocrine System Characteristics of Hormones Endocrine Glands & Their Hormones Pituitary & ... Thyroid & Parathyroid Glands Adrenal Gland Pancreas Gonads Other Endocrine Glands ... Cardiovascular System Heart Structure of the Heart Physiology of the ...

  14. Plant physiological models of heat, water and photoinhibition stress for climate change modelling and agricultural prediction

    NASA Astrophysics Data System (ADS)

    Nicolas, B.; Gilbert, M. E.; Paw U, K. T.

    2015-12-01

    Soil-Vegetation-Atmosphere Transfer (SVAT) models are based upon well understood steady state photosynthetic physiology - the Farquhar-von Caemmerer-Berry model (FvCB). However, representations of physiological stress and damage have not been successfully integrated into SVAT models. Generally, it has been assumed that plants will strive to conserve water at higher temperatures by reducing stomatal conductance or adjusting osmotic balance, until potentially damaging temperatures and the need for evaporative cooling become more important than water conservation. A key point is that damage is the result of combined stresses: drought leads to stomatal closure, less evaporative cooling, high leaf temperature, less photosynthetic dissipation of absorbed energy, all coupled with high light (photosynthetic photon flux density; PPFD). This leads to excess absorbed energy by Photosystem II (PSII) and results in photoinhibition and damage, neither are included in SVAT models. Current representations of photoinhibition are treated as a function of PPFD, not as a function of constrained photosynthesis under heat or water. Thus, it seems unlikely that current models can predict responses of vegetation to climate variability and change. We propose a dynamic model of damage to Rubisco and RuBP-regeneration that accounts, mechanistically, for the interactions between high temperature, light, and constrained photosynthesis under drought. Further, these predictions are illustrated by key experiments allowing model validation. We also integrated this new framework within the Advanced Canopy-Atmosphere-Soil Algorithm (ACASA). Preliminary results show that our approach can be used to predict reasonable photosynthetic dynamics. For instances, a leaf undergoing one day of drought stress will quickly decrease its maximum quantum yield of PSII (Fv/Fm), but it won't recover to unstressed levels for several days. Consequently, cumulative effect of photoinhibition on photosynthesis can cause

  15. Physiological response of wild dugongs (Dugong dugon) to out-of-water sampling for health assessment

    USGS Publications Warehouse

    Lanyon, Janet M.; Sneath, Helen L.; Long, Trevor; Bonde, Robert K.

    2010-01-01

    The dugong (Dugong dugon) is a vulnerable marine mammal with large populations living in urban Queensland waters. A mark-recapture program for wild dugongs has been ongoing in southern Queensland since 2001. This program has involved capture and in-water sampling of more than 700 dugongs where animals have been held at the water surface for 5 min to be gene-tagged, measured, and biopsied. In 2008, this program expanded to examine more comprehensively body condition, reproductive status, and the health of wild dugongs in Moreton Bay. Using Sea World's research vessel, captured dugongs were lifted onto a boat and sampled out-of-water to obtain accurate body weights and morphometrics, collect blood and urine samples for baseline health parameters and hormone profiles, and ultrasound females for pregnancy status. In all, 30 dugongs, including two pregnant females, were sampled over 10 d and restrained on deck for up to 55 min each while biological data were collected. Each of the dugongs had their basic temperature-heart rate-respiration (THR) monitored throughout their period of handling, following protocols developed for the West Indian manatee (Trichechus manatus). This paper reports on the physiological response of captured dugongs during this out-of-water operation as indicated by their vital signs and the suitability of the manatee monitoring protocols to this related sirenian species. A recommendation is made that the range of vital signs of these wild dugongs be used as benchmark criteria of normal parameters for other studies that intend to sample dugongs out-of-water.

  16. Effect of water compressibility on nonstationary characteristics of hydraulic turbines

    NASA Astrophysics Data System (ADS)

    Kurzin, V. B.

    2013-09-01

    We have investigated the effect of water compressibility on the nonstationary characteristics of turbines connected with the ability of the liquid to execute natural hydroacoustic vibrations in the setting of hydroelectric units. We have constructed a model of the setting up of forced hydroacoustic vibrations in the water conduit due to the precession of the vortex core running off the turbine. The conditions for the possibility that low-frequency hydroacoustic natural vibrations will arise have been considered.

  17. Physiological characteristics of Thiomicrospira sp. strain L-12 isolated from deep-sea hydrothermal vents

    SciTech Connect

    Ruby, E.G.; Jannasch, H.W.

    1982-01-01

    Growth of the obligately chemolithotrophic Thiomicrospira sp. strain L-12, isolated from a hydrothermal vent at a depth of 2,550 m in the Galapagos Rift region, was optimal at pH 8 and required 200 mM Na/sup +/ and divalent ions (Ca/sup 2 +/ and Mg/sup 2 +/). The organism was microaerophilic and tolerated 300 ..mu..M sulfide without a decrease in the rate of CO/sub 2/ incorporation. Growth and CO/sub 2/ incorporation occurred within the temperature range of 10 to 35/sup 0/C, with both optimal at 25/sup 0/C. At the in situ pressure of 250 atm, the rate of CO/sub 2/ incorporation was reduced by 25% relative to that measured at 1 atm; it was entirely suppressed at 500 atm. The results of this physiological characterization suggest that Thiomicrospira sp. strain L-12 can be an active autotroph in the hydrothermal environment.

  18. Morphological, physiological and enzymatic characteristics of cephalosporin acylase-producing Arthrobacter strain 45-8A.

    PubMed

    Zhang, Q J; Xu, W X

    1993-01-01

    A bacterial strain producing cephalosporin acylases was isolated from soil. The morphological and physiological properties of this strain suggest that it belongs to the genus Arthrobacter, and the isolate was therefore designated Arthrobacter strain 45-8A. Substrate specificity of the enzyme was examined. The enzyme can convert both cephalosporin acid to 7-aminocephalosporanic acid. An interesting feature of the acylases is their temperature-dependent regulation. Activity of acylases was detected in strain 45-8A grown at temperature below 30 degrees C, but was not observed at higher temperature. Arthrobacter strain 45-8A did not exhibit beta-lactamase activity, even though its resistance to cephalosporin C was very strong (> 2000 micrograms/ml). This is quite beneficial for its application in the manufacture of 7-aminocephalosporanic acid. PMID:8484708

  19. Differential responses of grapevine rootstocks to water stress are associated with adjustments in fine root hydraulic physiology and suberization.

    PubMed

    Barrios-Masias, F H; Knipfer, T; McElrone, A J

    2015-09-01

    Water deficits are known to alter fine root structure and function, but little is known about how these responses contribute to differences in drought resistance across grapevine rootstocks. The ways in which water deficit affects root anatomical and physiological characteristics were studied in two grapevine rootstocks considered as low-medium (101-14Mgt) and highly (110R) drought resistant. Rootstocks were grown under prolonged and repeated drying cycles or frequent watering ('dry' and 'wet' treatments, respectively), and the following parameters were evaluated: root osmotic and hydrostatic hydraulic conductivity (Lp os and Lp hyd, respectively), suberization, steady-state root pressure (P rs), sap exudation rates, sap osmotic potential, and exosmotic relaxation curves. For both rootstocks, the 'dry' treatment reduced fine root Lp, elicited earlier root suberization and higher sap osmotic potential, and generated greater P rs after rewatering, but the rootstocks responded differently under these conditions. Lp os, Lp hyd, and sap exudation rates were significantly higher in 110R than in 101-14Mgt, regardless of moisture treatment. Under 'dry' conditions, 110R maintained a similar Lp os and decreased the Lp hyd by 36% compared with 'wet' conditions, while both parameters were decreased by at least 50% for 101-14Mgt under 'dry' conditions. Interestingly, build-up of P rs in 110R was 34% lower on average than in 101-14Mgt, suggesting differences in the development of suberized apoplastic barriers between the rootstocks as visualized by analysis of suberization from fluorescence microscopy. Consistent with this pattern, 110R exhibited the greatest exosmotic Lp os (i.e. Lp os of water flowing from roots to the soil) as determined from relaxation curves under wet conditions, where backflow may have limited its capacity to generate positive xylem pressure. The traits studied here can be used in combination to provide new insights needed for screening drought resistance

  20. Differential responses of grapevine rootstocks to water stress are associated with adjustments in fine root hydraulic physiology and suberization

    PubMed Central

    Barrios-Masias, F.H.; Knipfer, T.; McElrone, A.J.

    2015-01-01

    Water deficits are known to alter fine root structure and function, but little is known about how these responses contribute to differences in drought resistance across grapevine rootstocks. The ways in which water deficit affects root anatomical and physiological characteristics were studied in two grapevine rootstocks considered as low–medium (101-14Mgt) and highly (110R) drought resistant. Rootstocks were grown under prolonged and repeated drying cycles or frequent watering (‘dry’ and ‘wet’ treatments, respectively), and the following parameters were evaluated: root osmotic and hydrostatic hydraulic conductivity (Lp os and Lp hyd, respectively), suberization, steady-state root pressure (P rs), sap exudation rates, sap osmotic potential, and exosmotic relaxation curves. For both rootstocks, the ‘dry’ treatment reduced fine root Lp, elicited earlier root suberization and higher sap osmotic potential, and generated greater P rs after rewatering, but the rootstocks responded differently under these conditions. Lp os, Lp hyd, and sap exudation rates were significantly higher in 110R than in 101-14Mgt, regardless of moisture treatment. Under ‘dry’ conditions, 110R maintained a similar Lp os and decreased the Lp hyd by 36% compared with ‘wet’ conditions, while both parameters were decreased by at least 50% for 101-14Mgt under ‘dry’ conditions. Interestingly, build-up of P rs in 110R was 34% lower on average than in 101-14Mgt, suggesting differences in the development of suberized apoplastic barriers between the rootstocks as visualized by analysis of suberization from fluorescence microscopy. Consistent with this pattern, 110R exhibited the greatest exosmotic Lp os (i.e. Lp os of water flowing from roots to the soil) as determined from relaxation curves under wet conditions, where backflow may have limited its capacity to generate positive xylem pressure. The traits studied here can be used in combination to provide new insights needed for

  1. Effects of Maternally-Transferred Methylmercury on Stress Physiology in Northern Water Snake (Nerodia sipedon) Neonates.

    PubMed

    Cusaac, J Patrick W; Kremer, Victoria; Wright, Raymond; Henry, Cassandra; Otter, Ryan R; Bailey, Frank C

    2016-06-01

    Biomagnification of methylmercury in aquatic systems can cause elevated tissue mercury (Hg) and physiological stress in top predators. Mercury is known to affect stress hormone levels in mammals, birds and fish. In this study, the effects of maternally-transferred methylmercury on the stress physiology of Northern Water Snake (Nerodia sipedon) neonates were tested. Gravid females were dosed via force-fed capsules during late gestation with 0, 0.01, or 10 µg methylmercury per gram of body mass. Plasma corticosterone levels and leukocyte differentials were analyzed in baseline and confinement-stressed neonates from all dose levels. Neither Hg nor confinement stress had a significant effect on leukocyte differentials nor was Hg related to corticosterone levels. However, stress group neonates showed lower heterophil/lymphocyte ratios and this study was the first to show that neonate N. sipedon can upregulate CORT in response to stress. These results indicate that N. sipedon may be somewhat tolerant to Hg contamination. PMID:26886428

  2. Gene expression and physiological responses to salinity and water stress of contrasting durum wheat genotypes.

    PubMed

    Yousfi, Salima; Márquez, Antonio J; Betti, Marco; Araus, José Luis; Serret, Maria Dolores

    2016-01-01

    Elucidating the relationships between gene expression and the physiological mechanisms remains a bottleneck in breeding for resistance to salinity and drought. This study related the expression of key target genes with the physiological performance of durum wheat under different combinations of salinity and irrigation. The candidate genes assayed included two encoding for the DREB (dehydration responsive element binding) transcription factors TaDREB1A and TaDREB2B, another two for the cytosolic and plastidic glutamine synthetase (TaGS1 and TaGS2), and one for the specific Na(+) /H(+) vacuolar antiporter (TaNHX1). Expression of these genes was related to growth and different trait indicators of nitrogen metabolism (nitrogen content, stable nitrogen isotope composition, and glutamine synthetase and nitrate reductase activities), photosynthetic carbon metabolism (stable carbon isotope composition and different gas exchange traits) and ion accumulation. Significant interaction between genotype and growing conditions occurred for growth, nitrogen content, and the expression of most genes. In general terms, higher expression of TaGS1, TaGS2, TaDREB2B, and to a lesser extent of TaNHX1 were associated with a better genotypic performance in growth, nitrogen, and carbon photosynthetic metabolism under salinity and water stress. However, TaDREB1A was increased in expression under stress compared with control conditions, with tolerant genotypes exhibiting lower expression than susceptible ones. PMID:25869057

  3. Physiology of Fluid and Electrolyte Responses During Inactivity: Water Immersion and Bed Rest

    NASA Technical Reports Server (NTRS)

    Greenleaf, John E.

    1984-01-01

    This manuscript emphasizes the physiology of fluid-electrolyte-hormonal responses during the prolonged inactivity of bed rest and water immersion. An understanding of the total mechanism of adaptation (deconditioning) should provide more insight into the conditioning process. Findings that need to be confirmed during bed rest and immersion are: (1) the volume and tissues of origin of fluid shifted to the thorax and head; (2) interstitial fluid pressure changes in muscle and subcutaneous tissue, particularly during immersion; and (3) the composition of the incoming presumably interstitial fluid that contributes to the early hypervolemia. Better resolution of the time course and source of the diuretic fluid is needed. Important data will be forthcoming when hypotheses are tested involving the probable action of the emerging diuretic and natriuretic hormones, between themselves and among vasopressin and aldosterone, on diuresis and blood pressure control.

  4. Relation of Spectral and Physiological Properties to Leaf Structural Characteristics of Arsenic Treated Rice Plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Arsenic (As) is a widely spread soil contaminant which can cause toxicity in plants. Although many studies have investigated the spectral characteristics of affected plants, the extent to which different toxicities may result in correspondingly different spectral signatures has received little atte...

  5. Physiological performance of the cold-water coral Dendrophyllia cornigera reveals its preference for temperate environments

    NASA Astrophysics Data System (ADS)

    Gori, Andrea; Reynaud, Stephanie; Orejas, Covadonga; Gili, Josep-Maria; Ferrier-Pagès, Christine

    2014-09-01

    Cold-water corals (CWCs) are key ecosystem engineers in deep-sea benthic communities around the world. Their distribution patterns are related to several abiotic and biotic factors, of which seawater temperature is arguably one of the most important due to its role in coral physiological processes. The CWC Dendrophyllia cornigera has the particular ability to thrive in several locations in which temperatures range from 11 to 17 °C, but to be apparently absent from most CWC reefs at temperatures constantly below 11 °C. This study thus aimed to assess the thermal tolerance of this CWC species, collected in the Mediterranean Sea at 12 °C, and grown at the three relevant temperatures of 8, 12, and 16 °C. This species displayed thermal tolerance to the large range of seawater temperatures investigated, but growth, calcification, respiration, and total organic carbon (TOC) fluxes severely decreased at 8 °C compared to the in situ temperature of 12 °C. Conversely, no significant differences in calcification, respiration, and TOC fluxes were observed between corals maintained at 12 and 16 °C, suggesting that the fitness of this CWC is higher in temperate rather than cold environments. The capacity to maintain physiological functions between 12 and 16 °C allows D. cornigera to be the most abundant CWC species in deep-sea ecosystems where temperatures are too warm for other CWC species (e.g., Canary Islands). This study also shows that not all CWC species occurring in the Mediterranean Sea (at deep-water temperatures of 12-14 °C) are currently living at their upper thermal tolerance limit.

  6. Effects of de-icing salt on ground water characteristics.

    PubMed

    O'Brien, J E; Majewski, J C

    1975-01-01

    The effect of "road salt" on the characteristics of Massachusetts drinking water supplies has been significant and cumulative rather than transient or seasonal. De-icing salt is essentially all sodium chloride. Calcium chloride accounted for only three percent of the total salt used. However, hardness content, as well as sodium ion concentration, has increased greatly in ground waters in the past decade. The changing composition of our water supplies has agricultural, economic, and public health implications. This study attempts to quantify the stoichiometry of these changes in concentration, which are in part due to an ion-exchange mechanism in the soil. PMID:238830

  7. Evidence that elevated water temperature affects the reproductive physiology of the European bullhead Cottus gobio.

    PubMed

    Dorts, Jennifer; Grenouillet, Gaël; Douxfils, Jessica; Mandiki, Syaghalirwa N M; Milla, Sylvain; Silvestre, Frédéric; Kestemont, Patrick

    2012-04-01

    Climate change is predicted to increase the average water temperature and alter the ecology and physiology of several organisms including fish species. To examine the effects of increased water temperature on freshwater fish reproduction, adult European bullhead Cottus gobio of both genders were maintained under three temperature regimes (T1: 6-10, T2: 10-14 and T3: 14-18°C) and assessed for gonad development (gonadosomatic index-GSI and gonad histology), sex steroids (testosterone-T, 17β-estradiol-E2 and 11-ketotestosterone-11-KT) and vitellogenin (alkali-labile phosphoprotein phosphorus-ALP) dynamics in December, January, February and March. The results indicate that a 8°C rise in water temperature (T3) deeply disrupted the gonadal maturation in both genders. This observation was associated with the absence of GSI peak from January to March, and low levels of plasma sex steroids compared with T1-exposed fish. Nevertheless, exposure to an increasing temperature of 4°C (T2) appeared to accelerate oogenesis with an early peak value in GSI and level of plasma T recorded in January relative to T1-exposed females. In males, the low GSI, reduced level of plasma 11-KT and the absence of GSI increase from January to March support the deleterious effects of increasing water temperature on spermatogenesis. The findings of the present study suggest that exposure to elevated temperatures within the context of climate warming might affect the reproductive success of C. gobio. Specifically, a 4°C rise in water temperature affects gametogenesis by advancing the spawning, and a complete reproductive failure is observed at an elevated temperature of 8°C. PMID:21638008

  8. Physiological and biochemical characteristics of the ethyl tiglate production pathway in the yeast Saprochaete suaveolens.

    PubMed

    Grondin, Eric; Shum Cheong Sing, Alain; Caro, Yanis; de Billerbeck, Gustavo M; François, Jean Marie; Petit, Thomas

    2015-01-01

    A yeast identified as Saprochaete suaveolens was investigated for its capacity to produce a large panel of flavouring molecules. With a production of 32 compounds including 28 esters, S. suaveolens seems to be a good producer of fruity flavours and fragrances and especially of unsaturated esters, such as ethyl tiglate. Physiological and biochemical analyses were performed in this study in an attempt to comprehend the metabolic route to the formation of this compound. We show that the accumulation of ethyl tiglate by S. suaveolens is specifically induced by isoleucine. However, and contrary to S. cerevisiae, which harbours a classical Ehrlich pathway leading to the production of 2-methylbutanol from isoleucine, our results provide phenotypic and enzymological evidence of ethyl tiglate biosynthesis in S. suaveolens through the catabolism of this amino acid by the β-oxidation pathway, which generates tiglyl-CoA as a probable intermediate. A kinetic analysis of this flavour molecule during growth of S. suaveolens on glucose and isoleucine showed a phase of production of ethyl tiglate that culminated concurrently with isoleucine exhaustion, followed by a disappearance of this compound, likely due to reassimilation by the yeast. PMID:25407290

  9. The Relationship of Physical Activity and Anthropometric and Physiological Characteristics to Bone Mineral Density in Postmenopausal Women.

    PubMed

    Arazi, Hamid; Eghbali, Ehsan; Saeedi, Tahmineh; Moghadam, Roya

    2016-01-01

    The aim of this study is to investigate the relationship of physical activity and anthropometric and physiological characteristics to bone mineral density (BMD) in postmenopausal women. Ninety-seven postmenopausal women with an average age of 50.71 ± 6.86 yr were selected to participate in this study. After completing consent forms and the questionnaire on physical activity, the amounts of calcium and 25-hydroxyvitamin D levels in participants' blood were measured by blood tests. The BMDs of the subjects in the lumbar spine (L2-L4) and hip were measured by dual-energy X-ray absorptiometry device and the results were recorded. Also, anthropometric characteristics including height, weight, body fat percentage, body mass index, waist-to-hip ratio (WHR), digit ratio (2D:4D), skeletal muscle mass index, hand and calf circumferences and physiological parameters, including handgrip strength, quadriceps isotonic extension strength and balance of the subjects, were measured. The results showed that the 2D:4D ratio and skeletal muscle mass index had a significantly positive relationship with BMD of the lumbar spine (p ≤ 0.05) and the hip (p ≤ 0.05). Also, there was a negative relationship between the BMD of lumbar spine and hip and WHR (p ≤ 0.05). Moreover, there was a positive relationship between the calf circumferences and lumbar spine BMD (p ≤ 0.05). Contrary to this, there was no significant relationship between the calf circumference and the hip BMD, and between hand circumference with lumbar spine and hip BMD (p > 0.05). Results of physiological indices showed a significant positive relationship between physical activity, handgrip strength, quadriceps isotonic extension strength, standing on 1 foot with the lumbar spine and hip BMD (p ≤ 0.05). But the relationship was not observed between BMD and the ability to squat down on the floor (p > 0.05). Based on these results, it seemed that we can use some physiological and

  10. [Stable Isotope Characteristics in Different Water Bodies in Changsha and Implications for the Water Cycle].

    PubMed

    Li, Guang; Zhang, Xin-ping; Zhang, Li-feng; Wang, Yue-feng; Deng, Xiao-jun; Yang, Liu; Lei, Chao-gui

    2015-06-01

    Analysis of the variation characteristics of different water bodies is the basis of applying isotopic tracer technique in regional water cycle research. Based on the samples of atmospheric precipitation, surface water (river water) and groundwater (spring water and well water) in Changsha from January 2012 to December 2013, the study analyzed the variation characteristics of δD and δ(18)O in different water bodies. The results showed that the values of D and 18O in precipitation of Changsha showed obvious seasonal variation because of the seasonal difference of the water vapor source, and it showed significant negative correlation between δ(18)O in precipitation and some meteorological factors such as the temperature and the amount, the local meteoric water line revealed the climatic characteristic of humid and rainy in Changsha; the fluctuation of 8D and 80 in surface water was more moderate than those in precipitation, and the seasonal variation of stable isotope value showed lagging characteristic compared with that in precipitation, the difference of river water line (RWL) indicated that the main supply sources of surface water were changing in different seasons; the fluctuation of δD and δ(18)O in groundwater was the least, the variation ranges and mean values of δD and δ(18)O in spring water and well water were very close, it showed that there were some hydraulic connections in the two water bodies, the values of δD and δ(18)O in groundwater were constantly lower during drought months, this phenomenon might have a certain relationship with the increasing absorbency of tree roots from groundwater. The results of the study have certain guiding significance for rational utilization of water resources in the region. PMID:26387312

  11. Development of physiologically based toxicokinetic models for improving the human indoor exposure assessment to water contaminants: trichloroethylene and trihalomethanes.

    PubMed

    Haddad, Sami; Tardif, Ginette-Charest; Tardif, Robert

    2006-12-01

    Generally, ingestion is the only route of exposure that is considered in the risk assessment of drinking water contaminants. However, it is well known that a number of these contaminants are volatile and lipophilic and therefore highly susceptible to being absorbed through other routes, mainly inhalation and dermal. The objective of this study was to develop physiologically based human toxicokinetic (PBTK) models for trihalomethanes (THM) and trichloroethylene (TCE) that will facilitate (1) the estimation of internal exposure to these chemicals for various multimedia indoor exposure scenarios, and (2) consideration of the impact of biological variability in the estimation of internal doses. Five PBTK models describing absorption through ingestion, inhalation and skin were developed for these contaminants. Their concentrations in ambient air were estimated from their respective tap water concentrations and their physicochemical characteristics. Algebraic descriptions of the physiological parameters, varying as a function of age, gender and diverse anthropometric parameters, allow the prediction of the influence of interindividual variations on absorbed dose and internal dosimetry. Simulations for various scenarios were done for a typical human (i.e., 70 kg, 1.7 m) as well as for humans of both genders varying in age from 1 to 90 years. Simulations show that ingestion contributes to less than 50% of the total absorbed dose or metabolized dose for all chemicals. This contribution to internal dosimetry, such as maximal venous blood concentrations (Cmax) and the area under the venous blood concentration time curve (AUC), decreases markedly (e.g., as low as 0.9% of Cmax for bromodichloromethane). The importance of this contribution varies mainly as a function of shower duration. Moreover, model simulations indicate that multimedia exposure is more elevated in children than adults (i.e., up to 200% of the adult internal dose). The models developed in this study allow

  12. Liquid state DNP for water accessibility measurements on spin-labeled membrane proteins at physiological temperatures.

    PubMed

    Doll, Andrin; Bordignon, Enrica; Joseph, Benesh; Tschaggelar, René; Jeschke, Gunnar

    2012-09-01

    We demonstrate the application of continuous wave dynamic nuclear polarization (DNP) at 0.35 T for site-specific water accessibility studies on spin-labeled membrane proteins at concentrations in the 10-100 μM range. The DNP effects at such low concentrations are weak and the experimentally achievable dynamic nuclear polarizations can be below the equilibrium polarization. This sensitivity problem is solved with an optimized home-built DNP probe head consisting of a dielectric microwave resonator and a saddle coil as close as possible to the sample. The performance of the probe head is demonstrated with both a modified pulsed EPR spectrometer and a dedicated CW EPR spectrometer equipped with a commercial NMR console. In comparison to a commercial pulsed ENDOR resonator, the home-built resonator has an FID detection sensitivity improvement of 2.15 and an electron spin excitation field improvement of 1.2. The reproducibility of the DNP results is tested on the water soluble maltose binding protein MalE of the ABC maltose importer, where we determine a net standard deviation of 9% in the primary DNP data in the concentration range between 10 and 100 μM. DNP parameters are measured in a spin-labeled membrane protein, namely the vitamin B(12) importer BtuCD in both detergent-solubilized and reconstituted states. The data obtained in different nucleotide states in the presence and absence of binding protein BtuF reveal the applicability of this technique to qualitatively extract water accessibility changes between different conformations by the ratio of primary DNP parameters ϵ. The ϵ-ratio unveils the physiologically relevant transmembrane communication in the transporter in terms of changes in water accessibility at the cytoplasmic gate of the protein induced by both BtuF binding at the periplasmic region of the transporter and ATP binding at the cytoplasmic nucleotide binding domains. PMID:22820007

  13. Liquid state DNP for water accessibility measurements on spin-labeled membrane proteins at physiological temperatures

    NASA Astrophysics Data System (ADS)

    Doll, Andrin; Bordignon, Enrica; Joseph, Benesh; Tschaggelar, René; Jeschke, Gunnar

    2012-09-01

    We demonstrate the application of continuous wave dynamic nuclear polarization (DNP) at 0.35 T for site-specific water accessibility studies on spin-labeled membrane proteins at concentrations in the 10-100 μM range. The DNP effects at such low concentrations are weak and the experimentally achievable dynamic nuclear polarizations can be below the equilibrium polarization. This sensitivity problem is solved with an optimized home-built DNP probe head consisting of a dielectric microwave resonator and a saddle coil as close as possible to the sample. The performance of the probe head is demonstrated with both a modified pulsed EPR spectrometer and a dedicated CW EPR spectrometer equipped with a commercial NMR console. In comparison to a commercial pulsed ENDOR resonator, the home-built resonator has an FID detection sensitivity improvement of 2.15 and an electron spin excitation field improvement of 1.2. The reproducibility of the DNP results is tested on the water soluble maltose binding protein MalE of the ABC maltose importer, where we determine a net standard deviation of 9% in the primary DNP data in the concentration range between 10 and 100 μM. DNP parameters are measured in a spin-labeled membrane protein, namely the vitamin B12 importer BtuCD in both detergent-solubilized and reconstituted states. The data obtained in different nucleotide states in the presence and absence of binding protein BtuF reveal the applicability of this technique to qualitatively extract water accessibility changes between different conformations by the ratio of primary DNP parameters ɛ. The ɛ-ratio unveils the physiologically relevant transmembrane communication in the transporter in terms of changes in water accessibility at the cytoplasmic gate of the protein induced by both BtuF binding at the periplasmic region of the transporter and ATP binding at the cytoplasmic nucleotide binding domains.

  14. Physiological Responses of a Model Marine Diatom to Fast pH Changes: Special Implications of Coastal Water Acidification

    PubMed Central

    Wu, Yaping; Beardall, John; Gao, Kunshan

    2015-01-01

    Diatoms and other phytoplankton in coastal waters experience rapid pH changes in milieu due to high biological activities and/or upwelled CO2-rich waters. While CO2 concentrating mechanisms (CCMs) are employed by all diatoms tested to counter low CO2 availability in seawater, little is known how this mechanism responds to fast pH changes. In the present study, the model diatom Thalassiosira pseudonana was acclimated for 20 generations to low pH (7.81) at an elevated CO2 of 1000 μatm (HC) or to high pH (8.18) at ambient CO2 levels of 390 μatm (LC), then its physiological characteristics were investigated as cells were shifted from HC to LC or vice versa. The maximal electron transport rate (ETRmax) in the HC-acclimated cells was immediately reduced by decreased CO2 availability, showing much lower values compared to that of the LC-acclimated cells. However, the cells showed a high capacity to regain their photochemical performance regardless of the growth CO2 levels, with their ETRmax values recovering to initial levels in about 100 min. This result indicates that this diatom might modulate its CCMs quickly to maintain a steady state supply of CO2, which is required for sustaining photosynthesis. In addition, active uptake of CO2 could play a fundamental role during the induction of CCMs under CO2 limitation, since the cells maintained high ETR even when both intracellular and periplasmic carbonic anhydrases were inhibited. It is concluded that efficient regulation of the CCM is one of the key strategies for diatoms to survive in fast changing pH environment, e.g. for the tested species, which is a dominant species in coastal waters where highly fluctuating pH is observed. PMID:26496125

  15. Physiological Characteristics of Photosynthesis and Respiration in Stems of Populus tremuloides Michx. 1

    PubMed Central

    Foote, Knowlton C.; Schaedle, Michail

    1976-01-01

    The physiological responses of 6- to 8-year-old aspen (Populus tremuloides Michx.) stems to temperature, light, and CO2 concentration were investigated in the field throughout the year using infrared CO2 analysis. Light response studies showed that the rate of gross photosynthesis was linear from 0 to 400 ft-c (0 to 1.6 mw/cm2 of 400-700 nm) with light saturation being reached between 800 to 1400 ft-c (3.2 to 5.6 mw/cm2 of 400-700 nm). At this light intensity, the respiratory CO2 loss was reduced to 10 to 15% of dark rates. Net photosynthetic CO2 uptake was not observed even at intensities as high as 3400 ft-c (13.6 mw/cm2 of 400-700 nm). The light response curve was similar for both winter and summer stems. During summer months, the respiratory and photosynthetic rates of the aspen stem increased with temperature at a near constant rate between 5 and 35 C. For winter stems, the gross photosynthetic rate increased in a pattern similar to the dark respiratory rate as the temperature rose from 3 to 17 C. Below 0 C and above 17 C, however, the gross photosynthetic rate fell off in relation to the respiratory rate so that the per cent of CO2 reassimilated decreased from 75% to less than 50%. Measurable bark photosynthetic activity was not observed below —3 C. The gross photosynthetic rate of stems was not affected when the gas passing through the cuvette contained concentrations of CO2 ranging from 0 to 580 μl CO2/l air. PMID:16659628

  16. Physiological responses of radiata pine roots to soil strength and soil water deficit.

    PubMed

    Zou, Chris; Sands, Roger; Sun, Osbert

    2000-11-01

    We investigated physiological responses of radiata pine (Pinus radiata D. Don) roots to soil strength and soil water deficit by measuring the osmotic potential (Psi(pi)) and yield turgor (Y) in the elongation zone of root segments of seedlings growing (i) in polyethylene glycol 4000-containing rooting solution of different water potentials (Psi(s)) and (ii) in soil of different soil strengths (Q) at the same soil matric potential (Psi(m)). Root elongation rate (Deltal/Deltat) decreased progressively with decreasing Psi(s) and was associated with decreased Psi(pi) and decreased turgor pressure (P). Osmotic adjustment occurred at Psi(s) < -0.2 MPa. Over a range in Psi(s) of -0.01 to -1.0 MPa, Psi(pi) fell 0.3 MPa whereas P fell 0.7 MPa. Mean Psi in the solution experiment was 0.37 MPa and did not differ significantly with Psi(s) (P = 0.10). Root elongation rate decreased exponentially as Q increased from 0 to 3.0 MPa, and was associated with an increase in P of 0.11 MPa as a consequence of Psi(pi) decreasing by the same amount. Mean Y in the soil experiment was 0.49 MPa and did not change significantly with Q (P = 0.87). PMID:12651497

  17. Infrared thermal imaging as a physiological access pathway: a study of the baseline characteristics of facial skin temperatures.

    PubMed

    Nhan, B R; Chau, T

    2009-04-01

    In this study we examine the baseline characteristics of facial skin temperature, as measured by dynamic infrared thermal imaging, to gauge its potential as a physiological access pathway for non-verbal individuals with severe motor impairments. Frontal facial recordings were obtained from 12 asymptomatic adults in a resting state with a high-end infrared thermal imaging system. From the infrared thermal recordings, mean skin temperature time series were generated for regions of interest encompassing the nasal, periorbital and supraorbital areas. A 90% bandwidth for all regions of interest was found to be in the 1 Hz range. Over 70% of the time series were identified as nonstationary (p<0.05), with the nonstationary mean as the greatest contributing source. Correlation coefficients between regions were significant (p<0.05) and ranged from values of 0.30 (between periorbital and supraorbital regions) to 0.75 (between contralateral supraorbital regions). Using information measures, we concluded that the greatest degree of information existed in the nasal and periorbital regions. Mutual information existed across all regions but was especially prominent between the nasal and periorbital regions. Results from this study provide insight into appropriate analysis methods and potential discriminating features for the application of facial skin temperature as a physiological access pathway. PMID:19332894

  18. Cardiovascular and autonomic responses to physiological stressors before and after six hours of water immersion.

    PubMed

    Florian, John P; Simmons, Erin E; Chon, Ki H; Faes, Luca; Shykoff, Barbara E

    2013-11-01

    The physiological responses to water immersion (WI) are known; however, the responses to stress following WI are poorly characterized. Ten healthy men were exposed to three physiological stressors before and after a 6-h resting WI (32-33°C): 1) a 2-min cold pressor test, 2) a static handgrip test to fatigue at 40% of maximum strength followed by postexercise muscle ischemia in the exercising forearm, and 3) a 15-min 70° head-up-tilt (HUT) test. Heart rate (HR), systolic and diastolic blood pressure (SBP and DBP), cardiac output (Q), limb blood flow (BF), stroke volume (SV), systemic and calf or forearm vascular resistance (SVR and CVR or FVR), baroreflex sensitivity (BRS), and HR variability (HRV) frequency-domain variables [low-frequency (LF), high-frequency (HF), and normalized (n)] were measured. Cold pressor test showed lower HR, SBP, SV, Q, calf BF, LFnHRV, and LF/HFHRV and higher CVR and HFnHRV after than before WI (P < 0.05). Handgrip test showed no effect of WI on maximum strength and endurance and lower HR, SBP, SV, Q, and calf BF and higher SVR and CVR after than before WI (P < 0.05). During postexercise muscle ischemia, HFnHRV increased from baseline after WI only, and LFnHRV was lower after than before WI (P < 0.05). HUT test showed lower SBP, DBP, SV, forearm BF, and BRS and higher HR, FVR, LF/HFHRV, and LFnHRV after than before WI (P < 0.05). The changes suggest differential activation/depression during cold pressor and handgrip (reduced sympathetic/elevated parasympathetic) and HUT (elevated sympathetic/reduced parasympathetic) following 6 h of WI. PMID:23950166

  19. Using water to cool cattle: behavioral and physiological changes associated with voluntary use of cow showers.

    PubMed

    Legrand, A; Schütz, K E; Tucker, C B

    2011-07-01

    Water is commonly used to cool cattle in summer either at milking or over the feed bunk, but little research has examined how dairy cows voluntarily use water separate from these locations. The objectives were to describe how and when dairy cattle voluntarily used an overhead water source separate from other resources, such as feed, and how use of this water affected behavioral and physiological indicators of heat stress. Half of the 24 nonlactating cattle tested had access to a "cow shower" composed of 2 shower heads activated by a pressure-sensitive floor. All animals were individually housed to prevent competition for access to the shower. Over 5 d in summer (air temperature=25.3±3.3°C, mean ± standard deviation), cattle spent 3.0±2.1 h/24h in the shower, but considerable variability existed between animals (individual daily values ranged from 0.0 to 8.2 h/24h). A portion of this variation can be explained by weather; shower use increased by 0.3h for every 1°C increase in ambient temperature. Cows preferentially used the shower during the daytime, with 89±12% of the time spent in the shower between 1000 and 1900 h. Respiration rate and skin temperature did not differ between treatments [53 vs. 61 breaths/min and 35.0 vs. 35.4°C in shower and control cows, respectively; standard error of the difference (SED)=5.6 breaths/min and 0.49°C]. In contrast, body temperature of cows provided with a shower was 0.2°C lower than control cows in the evening (i.e., 1800 to 2100h; SED=0.11°C). Cows with access to a shower spent half as much time near the water trough than control animals, and this pattern became more pronounced as the temperature-humidity index increased. In addition, cattle showed other behavioral changes to increasing heat load; they spent less time lying when heat load index increased, but the time spent lying, feeding, and standing without feeding did not differ between treatments. Cows had higher respiration rate, skin temperature, and body

  20. Molecular, Physiological and Biochemical Responses of Theobroma cacao L. Genotypes to Soil Water Deficit

    PubMed Central

    dos Santos, Ivanildes C.; de Almeida, Alex-Alan Furtado; Anhert, Dário; da Conceição, Alessandro S.; Pirovani, Carlos P.; Pires, José L.; Valle, Raúl René; Baligar, Virupax C.

    2014-01-01

    Six months-old seminal plants of 36 cacao genotypes grown under greenhouse conditions were subjected to two soil water regimes (control and drought) to assess, the effects of water deficit on growth, chemical composition and oxidative stress. In the control, soil moisture was maintained near field capacity with leaf water potentials (ΨWL) ranging from −0.1 to −0.5 MPa. In the drought treatment, the soil moisture was reduced gradually by withholding additional water until ΨWL reached values of between −2.0 to −2.5 MPa. The tolerant genotypes PS-1319, MO-20 and MA-15 recorded significant increases in guaiacol peroxidase activity reflecting a more efficient antioxidant metabolism. In relation to drought tolerance, the most important variables in the distinguishing contrasting groups were: total leaf area per plant; leaf, stem and total dry biomass; relative growth rate; plant shoot biomass and leaf content of N, Ca, and Mg. From the results of these analyses, six genotypes were selected with contrasting characteristics for tolerance to soil water deficit [CC-40, C. SUL-4 and SIC-2 (non-tolerant) and MA-15, MO-20, and PA-13 (tolerant)] for further assessment of the expression of genes NCED5, PP2C, psbA and psbO to water deficit. Increased expression of NCED5, PP2C, psbA and psbO genes were found for non-tolerant genotypes, while in the majority of tolerant genotypes there was repression of these genes, with the exception of PA-13 that showed an increased expression of psbA. Mutivariate analysis showed that growth variables, leaf and total dry biomass, relative growth rate as well as Mg content of the leaves were the most important factor in the classification of the genotypes as tolerant, moderately tolerant and sensitive to water deficit. Therefore these variables are reliable plant traits in the selection of plants tolerant to drought. PMID:25541723

  1. Arbuscular Mycorrhizal Fungus Species Dependency Governs Better Plant Physiological Characteristics and Leaf Quality of Mulberry (Morus alba L.) Seedlings

    PubMed Central

    Shi, Song-Mei; Chen, Ke; Gao, Yuan; Liu, Bei; Yang, Xiao-Hong; Huang, Xian-Zhi; Liu, Gui-Xi; Zhu, Li-Quan; He, Xin-Hua

    2016-01-01

    Understanding the synergic interactions between arbuscular mycorrhizal fungi (AMF) and its host mulberry (Morus alba L.), an important perennial multipurpose plant, has theoretical and practical significance in mulberry plantation, silkworm cultivation, and relevant textile industry. In a greenhouse study, we compared functional distinctions of three genetically different AMF species (Acaulospora scrobiculata, Funneliformis mosseae, and Rhizophagus intraradices) on physiological and growth characteristics as well as leaf quality of 6-month-old mulberry seedlings. Results showed that mulberry was AMF-species dependent, and AMF colonization significantly increased shoot height and taproot length, stem base and taproot diameter, leaf and fibrous root numbers, and shoot and root biomass production. Meanwhile, leaf chlorophyll a or b and carotenoid concentrations, net photosynthetic rate, transpiration rate and stomatal conductance were generally significantly greater, while intercellular CO2 concentration was significantly lower in AMF-inoculated seedlings than in non-AMF-inoculated counterparts. These trends were also generally true for leaf moisture, total nitrogen, all essential amino acids, histidine, proline, soluble protein, sugar, and fatty acid as they were significantly increased under mycorrhization. Among these three tested AMFs, significantly greater effects of AMF on above-mentioned mulberry physiological and growth characteristics ranked as F. mosseae > A. scrobiculata > R. intraradices, whilst on mulberry leaf quality (e.g., nutraceutical values) for better silkworm growth as F. mosseae ≈A. scrobiculata > R. intraradices. In conclusion, our results showed that greater mulberry biomass production, and nutritional quality varied with AMF species or was AMF-species dependent. Such improvements were mainly attributed to AMF-induced positive alterations of mulberry leaf photosynthetic pigments, net photosynthetic rate, transpiration rate, and N

  2. Arbuscular Mycorrhizal Fungus Species Dependency Governs Better Plant Physiological Characteristics and Leaf Quality of Mulberry (Morus alba L.) Seedlings.

    PubMed

    Shi, Song-Mei; Chen, Ke; Gao, Yuan; Liu, Bei; Yang, Xiao-Hong; Huang, Xian-Zhi; Liu, Gui-Xi; Zhu, Li-Quan; He, Xin-Hua

    2016-01-01

    Understanding the synergic interactions between arbuscular mycorrhizal fungi (AMF) and its host mulberry (Morus alba L.), an important perennial multipurpose plant, has theoretical and practical significance in mulberry plantation, silkworm cultivation, and relevant textile industry. In a greenhouse study, we compared functional distinctions of three genetically different AMF species (Acaulospora scrobiculata, Funneliformis mosseae, and Rhizophagus intraradices) on physiological and growth characteristics as well as leaf quality of 6-month-old mulberry seedlings. Results showed that mulberry was AMF-species dependent, and AMF colonization significantly increased shoot height and taproot length, stem base and taproot diameter, leaf and fibrous root numbers, and shoot and root biomass production. Meanwhile, leaf chlorophyll a or b and carotenoid concentrations, net photosynthetic rate, transpiration rate and stomatal conductance were generally significantly greater, while intercellular CO2 concentration was significantly lower in AMF-inoculated seedlings than in non-AMF-inoculated counterparts. These trends were also generally true for leaf moisture, total nitrogen, all essential amino acids, histidine, proline, soluble protein, sugar, and fatty acid as they were significantly increased under mycorrhization. Among these three tested AMFs, significantly greater effects of AMF on above-mentioned mulberry physiological and growth characteristics ranked as F. mosseae > A. scrobiculata > R. intraradices, whilst on mulberry leaf quality (e.g., nutraceutical values) for better silkworm growth as F. mosseae ≈A. scrobiculata > R. intraradices. In conclusion, our results showed that greater mulberry biomass production, and nutritional quality varied with AMF species or was AMF-species dependent. Such improvements were mainly attributed to AMF-induced positive alterations of mulberry leaf photosynthetic pigments, net photosynthetic rate, transpiration rate, and N

  3. Characteristics of a root hair-less line of Arabidopsis thaliana under physiological stresses.

    PubMed

    Tanaka, Natsuki; Kato, Mariko; Tomioka, Rie; Kurata, Rie; Fukao, Yoichiro; Aoyama, Takashi; Maeshima, Masayoshi

    2014-04-01

    The plasma membrane-associated Ca(2+)-binding protein-2 of Arabidopsis thaliana is involved in the growth of root hair tips. Several transgenic lines that overexpress the 23 residue N-terminal domain of this protein under the control of the root hair-specific EXPANSIN A7 promoter lack root hairs completely. The role of root hairs under normal and stress conditions was examined in one of these root hair-less lines (NR23). Compared with the wild type, NR23 showed a 47% reduction in water absorption, decreased drought tolerance, and a lower ability to adapt to heat. Growth of NR23 was suppressed in media deficient in phosphorus, iron, calcium, zinc, copper, or potassium. Also, the content of an individual mineral in NR23 grown in normal medium, or in medium lacking a specific mineral, was relatively low. In wild-type plants, the primary and lateral roots produce numerous root hairs that become elongated under phosphate-deficient conditions; NR23 did not produce root hairs. Although several isoforms of the plasma membrane phosphate transporters including PHT1;1-PHT1;6 were markedly induced after growth in phosphate-deficient medium, the levels induced in NR23 were less than half those observed in the wild type. In phosphate-deficient medium, the amounts of acid phosphatase, malate, and citrate secreted from NR23 roots were 38, 9, and 16% of the levels secreted from wild-type roots. The present results suggest that root hairs play significant roles in the absorption of water and several minerals, secretion of acid phosphatase(s) and organic acids, and in penetration of the primary roots into gels. PMID:24501179

  4. Characteristics of a root hair-less line of Arabidopsis thaliana under physiological stresses

    PubMed Central

    Maeshima, Masayoshi

    2014-01-01

    The plasma membrane-associated Ca2+-binding protein-2 of Arabidopsis thaliana is involved in the growth of root hair tips. Several transgenic lines that overexpress the 23 residue N-terminal domain of this protein under the control of the root hair-specific EXPANSIN A7 promoter lack root hairs completely. The role of root hairs under normal and stress conditions was examined in one of these root hair-less lines (NR23). Compared with the wild type, NR23 showed a 47% reduction in water absorption, decreased drought tolerance, and a lower ability to adapt to heat. Growth of NR23 was suppressed in media deficient in phosphorus, iron, calcium, zinc, copper, or potassium. Also, the content of an individual mineral in NR23 grown in normal medium, or in medium lacking a specific mineral, was relatively low. In wild-type plants, the primary and lateral roots produce numerous root hairs that become elongated under phosphate-deficient conditions; NR23 did not produce root hairs. Although several isoforms of the plasma membrane phosphate transporters including PHT1;1–PHT1;6 were markedly induced after growth in phosphate-deficient medium, the levels induced in NR23 were less than half those observed in the wild type. In phosphate-deficient medium, the amounts of acid phosphatase, malate, and citrate secreted from NR23 roots were 38, 9, and 16% of the levels secreted from wild-type roots. The present results suggest that root hairs play significant roles in the absorption of water and several minerals, secretion of acid phosphatase(s) and organic acids, and in penetration of the primary roots into gels. PMID:24501179

  5. Characteristics of water and carbon balance in moso bamboo forests

    NASA Astrophysics Data System (ADS)

    Kume, T.; Laplace, S.; Tseng, H.; Hsieh, Y.; Wey, T.; Komatsu, H.

    2013-12-01

    Water and carbon cycles in mountainous areas can have considerable impacts on our available nature resources such as water resources and timber production. Thus, it is indispensable to clarify the difference of water and carbon balances between different types of forested ecosystems. Recently, bamboo forests have been expanding by replacing surrounding vegetation such as coniferous and broad-leaved forests in eastern Asian countries. It has been speculated that the replacements by bamboo forests could alter the vegetation water and carbon cycles. However, our knowledge for the bamboo forests was still limited due to lack of applicable methodology based on a field measurement. To clarify the potential impacts of bamboo expansion on water and carbon cycles, our previous study established optimal and effective design for assessing bamboo forest water use (ie, transpiration) based on sap flux measurements. Using the method, we quantified stand-scale transpiration in bamboo forests and coniferous forests in Taiwan. Consequently, we found significantly larger transpiration in bamboo forests compared with those of surrounding vegetation due to larger canopy conductance in bamboo forests. The unique characteristics of the water use accompanied larger carbon assimilation and soil CO2 efflux in bamboo forests.

  6. Physiological and Molecular Characteristics of Elicitin-Induced Systemic Acquired Resistance in Tobacco.

    PubMed Central

    Keller, H.; Blein, J. P.; Bonnet, P.; Ricci, P.

    1996-01-01

    Elicitins are low molecular weight proteins secreted by all Phytophthora species analyzed so far. Application of the purified proteins to tobacco Nicotiana tabacum leads to the induction of resistance to subsequent inoculations with the black shank-causing agent, Phytophthora parasitica var nicotianae. In this paper, we describe the systemic characteristics of elicitin-induced acquired resistance in tobacco. Elicitin application is followed by the rapid translocation of the protein in the plant. The basic elicitin, cryptogein, induces necrosis formation in the leaves, which results from accumulation of the protein in these organs. Necrosis does not seem to be essential for the establishment of systemic acquired resistance (SAR), since resistance induced by the acidic elicitin, capsicein, is not accompanied by the development of visible symptoms on the leaves. Both elicitins trigger the coordinate accumulation of transcripts from nine genes, previously described to be expressed during establishment of SAR. Additionally, elicitin treatment leads to the activation of the multiple response gene str 246. In leaves, transcript accumulation was found to be higher in all cases in response to cryptogein compared to capsicein treatment. These results, along with northern hybridization analysis following infiltration of leaves with cryptogein, indicate that SAR genes appear to be expressed locally, corresponding to necrosis formation as well as systemically during induction of resistance. To our knowledge, elicitins are the only well-characterized, pathogen-derived molecules that trigger SAR in a plant. PMID:12226188

  7. The effects of physiological adjustments on the perceptual and acoustical characteristics of simulated laryngeal vocal tremor

    PubMed Central

    Lester, Rosemary A.; Story, Brad H.

    2015-01-01

    The purpose of this study was to determine if adjustments to the voice source [i.e., fundamental frequency (F0), degree of vocal fold adduction] or vocal tract filter (i.e., vocal tract shape for vowels) reduce the perception of simulated laryngeal vocal tremor and to determine if listener perception could be explained by characteristics of the acoustical modulations. This research was carried out using a computational model of speech production that allowed for precise control and manipulation of the glottal and vocal tract configurations. Forty-two healthy adults participated in a perceptual study involving pair-comparisons of the magnitude of “shakiness” with simulated samples of laryngeal vocal tremor. Results revealed that listeners perceived a higher magnitude of voice modulation when simulated samples had a higher mean F0, greater degree of vocal fold adduction, and vocal tract shape for /i/ vs /ɑ/. However, the effect of F0 was significant only when glottal noise was not present in the acoustic signal. Acoustical analyses were performed with the simulated samples to determine the features that affected listeners' judgments. Based on regression analyses, listeners' judgments were predicted to some extent by modulation information present in both low and high frequency bands. PMID:26328711

  8. Behavioral, attitudinal, and physiologic characteristics of smoking and nonsmoking asbestos-exposed shipyard workers

    SciTech Connect

    Li, V.C.; Kim, Y.J.; Terry, P.B.; Cuthie, J.C.; Roter, D.; Emmett, E.A.; Harvey, A.; Permutt, S.

    1983-12-01

    The smoking characteristics of shipyard workers participating in an Asbestos Medical Surveillance Program (N=3991) were assessed. Sources of data were: 1) a self-assessment questionnaire on the smoking history and respiratory symptomatology of the 871 current smokers who participated in the smoking study, and 2) chest roentgenograms and pulmonary function test results and medical records for the entire population. The study population included 1711 current smokers, 988 former smokers and 1292 never smokers. The annual ''quit rate'' for former smokers had increased from less than 1% in 1961 to 4.2% in 1978. Of the 871 current smokers who participated in the smoking study, 19% had resumed smoking after having given up cigarettes for one year or longer. Men in the smoking study were reasonably well informed about the health consequences of smoking. While they perceived themselves to be susceptible to disease, and the disease to be serious, the benefits they saw in quitting were related more to economics and aesthetics than to health. When the results were age adjusted, no differences in rate of pulonary function abnormalities and chest film abnormalities were found betwen current smokers who voluntarily participated in the smoking study and those who did not. All pulmonary function testing abnormality and chest film abnormality rates were significantly lower for former smokers and never smokers.

  9. Foulant Characteristics Comparison in Recycling Cooling Water System Makeup by Municipal Reclaimed Water and Surface Water in Power Plant

    PubMed Central

    Ping, Xu; Jing, Wang; Yajun, Zhang; Jie, Wang; Shuai, Si

    2015-01-01

    Due to water shortage, municipal reclaimed water rather than surface water was replenished into recycling cooling water system in power plants in some cities in China. In order to understand the effects of the measure on carbon steel corrosion, characteristics of two kinds of foulant produced in different systems were studied in the paper. Differences between municipal reclaimed water and surface water were analyzed firstly. Then, the weight and the morphology of two kinds of foulant were compared. Moreover, other characteristics including the total number of bacteria, sulfate reducing bacteria, iron bacteria, extracellular polymeric substance (EPS), protein (PN), and polysaccharide (PS) in foulant were analyzed. Based on results, it could be concluded that microbial and corrosive risk would be increased when the system replenished by municipal reclaimed water instead of surface water. PMID:25893132

  10. Foulant characteristics comparison in recycling cooling water system makeup by municipal reclaimed water and surface water in power plant.

    PubMed

    Ping, Xu; Jing, Wang; Yajun, Zhang; Jie, Wang; Shuai, Si

    2015-01-01

    Due to water shortage, municipal reclaimed water rather than surface water was replenished into recycling cooling water system in power plants in some cities in China. In order to understand the effects of the measure on carbon steel corrosion, characteristics of two kinds of foulant produced in different systems were studied in the paper. Differences between municipal reclaimed water and surface water were analyzed firstly. Then, the weight and the morphology of two kinds of foulant were compared. Moreover, other characteristics including the total number of bacteria, sulfate reducing bacteria, iron bacteria, extracellular polymeric substance (EPS), protein (PN), and polysaccharide (PS) in foulant were analyzed. Based on results, it could be concluded that microbial and corrosive risk would be increased when the system replenished by municipal reclaimed water instead of surface water. PMID:25893132

  11. FISH PHYSIOLOGY, TOXICOLOGY, AND WATER QUALITY MANAGEMENT: PROCEEDINGS OF AN INTERNATIONAL SYMPOSIUM, SACRAMENTO, CALIFORNIA, USA, SEPTEMBER 18-20, 1993

    EPA Science Inventory

    Scientists from five countries presented papers at the Second International Symposium on Fish Physiology, Toxicology, and Water Quality Management, which was held in Sacramento, California, on September 18-20, 1990. his proceedings includes 21 papers presented in sessions on the ...

  12. Underwater polarization characteristics and their impact on water visibility

    NASA Astrophysics Data System (ADS)

    Zhou, Jing; Tonizzo, Alberto; Gilerson, Alex; Gross, Barry; Moshary, Fred; Ahmed, Sam

    2010-04-01

    In this paper we examine the impact of measured underwater polarization characteristics on visibility. Underwater characteristics were measured both in the principal plane and outside the principal plane, with data collected during several cruises in the Chesapeake/Virginia and New York Harbor/Hudson River areas using a multi-angular hyperspectral sensor system. This system, recently developed by us, consists of three hyperspectral Satlantic radiance sensors, each with a polarizer positioned in front of it, and with polarization axes aligned at 0, 90 and 45 deg. Underwater measurements are made with scattering angles from 0-180 degrees with respect to the solar illumination. At the same time as the hyperspectral measurements are made, the inherent optical properties such as absorption and attenuation were also recorded. The waters studied varied from clear open ocean water with attenuation of less than 0.25m-1 at 550nm c (550), to turbid coastal waters with a c(550) of more than 4m-1. In order to examine the extent that polarization techniques can help to improve underwater visibility in these types of field conditions, we computed the related modulation transfer functions from the polarized field measurements, and included the examination of the impact of scattered polarized veiling light, inherent in the field data. Various water parameters are then explored to examine the impact of the polarization of the background light in the principal plane on underwater visibility.

  13. Combining leaf physiology, hyperspectral imaging and partial least squares-regression (PLS-R) for grapevine water status assessment

    NASA Astrophysics Data System (ADS)

    Rapaport, Tal; Hochberg, Uri; Shoshany, Maxim; Karnieli, Arnon; Rachmilevitch, Shimon

    2015-11-01

    Physiological measurements are considered to be the most accurate way of assessing plant water status, but they might also be time-consuming, costly and intrusive. Since visible (VIS)-to-shortwave infrared (SWIR) imaging spectrometers are able to monitor various bio-chemical alterations in the leaf, such narrow-band instruments may offer a faster, less expensive and non-destructive alternative. This requires an intelligent downsizing of broad and noisy hyperspectra into the few most physiologically-sensitive wavelengths. In the current study, hyperspectral signatures of water-stressed grapevine leaves (Vitis vinifera L. cv. Cabernet Sauvignon) were correlated to values of midday leaf water potential (Ψl), stomatal conductance (gs) and non-photochemical quenching (NPQ) under controlled conditions, using the partial least squares-regression (PLS-R) technique. It was found that opposite reflectance trends at 530-550 nm and around 1500 nm - associated with independent changes in photoprotective pigment contents and water availability, respectively - were indicative of stress-induced alterations in Ψl, gs and NPQ. Furthermore, combining the spectral responses at these VIS and SWIR regions yielded three normalized water balance indices (WABIs), which were superior to various widely-used reflectance models in predicting physiological values at both the leaf and canopy levels. The potential of the novel WABI formulations also under field conditions demonstrates their applicability for water status monitoring and irrigation scheduling.

  14. Physiologic, metabolic, and muscle fiber type characteristics of musculus uvulae in sleep apnea hypopnea syndrome and in snorers.

    PubMed

    Sériès, F; Côté, C; Simoneau, J A; Gélinas, Y; St Pierre, S; Leclerc, J; Ferland, R; Marc, I

    1995-01-01

    Upper airway dilator muscles play an important role in the pathophysiology of sleep apnea hypopnea syndrome (SAHS). The mechanical and structural characteristics of these muscles remain unknown. The aim of this study was to compare the physiologic, metabolic, and fiber type characteristics of one upper airway dilator muscle (musculus uvulae, MU) in 11 SAHS and in seven nonapneic snorers. The different analyses were done on MU obtained during uvulo-palato-pharyngoplasty. Snorers and SAHS differed only in their apnea + hypopnea indices (11.5 +/- 5.9 and 34.2 +/- 14.6/h, respectively, mean +/- SD). Absolute twitch and tetanic tension production of MU was significantly greater in SAHS than in snorers while the fatigability index was similar in the two groups. Protein content and anaerobic enzyme activities of MU were significantly greater in SAHS than in snorers; no difference was observed for aerobic enzyme activities. The total muscle fiber cross-sectional area of MU was significantly higher in SAHS (2.2 +/- 0.9 mm2) than in snorers (1.1 +/- 0.7 mm2). The surface occupied by type IIA muscle fibers of MU was larger in SAHS (2.00 +/- 0.96) than in snorers (0.84 +/- 0.63 mm2). We conclude that the capacity for tension production and the anaerobic metabolic activity of MU are greater in SAHS than in snorers. PMID:7814616

  15. Exceptional thermal tolerance and water resistance in the mite Paratarsotomus macropalpis (Erythracaridae) challenge prevailing explanations of physiological limits.

    PubMed

    Wu, Grace C; Wright, Jonathan C

    2015-11-01

    Physiological performance and tolerance limits in metazoans have been widely studied and have informed our understanding of processes such as extreme heat and cold tolerance, and resistance to water loss. Because of scaling considerations, very small arthropods with extreme microclimatic niches provide promising extremophiles for testing predictive physiological models. Corollaries of small size include rapid heating and cooling (small thermal time constants) and high mass-specific metabolic and water exchange rates. This study examined thermal tolerance and water loss in the erythracarid mite Paratarsotomus macropalpis (Banks, 1916), a species that forages on the ground surface of the coastal sage scrub habitat of Southern California, USA. Unlike most surface-active diurnal arthropods, P. macropalpis remains active during the hottest parts of the day in midsummer. We measured water-loss gravimetrically and estimated the critical thermal maximum (CTmax) by exposing animals to a given temperature for 1h and then increasing temperature sequentially. The standardized water flux of 4.4ngh(-1)cm(-2)Pa(-1), averaged for temperatures between 22 and 40°C, is among the lowest values reported in the literature. The CTmax of 59.4°C is, to our knowledge, the highest metazoan value reported for chronic (1-h) exposure, and closely matches maximum field substrate temperatures during animal activity. The extraordinary physiological performance seen in P. macropalpis likely reflects extreme selection resulting from its small size and resultant high mass-specific water loss rate and low thermal time-constant. Nevertheless, the high water resistance attained with a very thin lipid barrier, and the mite's exceptional thermal tolerance, challenge existing theories seeking to explain physiological limits. PMID:26255840

  16. [Effects of different barnyardgrass species on grain yield of rice and their physiological characteristics under alternate wetting and drying irrigation].

    PubMed

    Zhang, Zi-chang; Li, Yong-feng; Yang, Xia; Gu, Tao; Li, Gui

    2015-11-01

    In order to investigate the influence of different barnyardgrass species on rice yield and physiological characteristics of rice, two rice cultivars, Liangyoupeijiu (an indica hybrid cultivar) and Nanjing 9108 (a japonica cultivar) , were employed to co-culture with four barnyardgrass species during the period from transplanting to maturity under alternate wetting and moderate drying ir- rigation condition. The treatments were separately designed as follow: weed free ( control) , rice with Echinochloa crusgalli var. mitis (T1), rice with E. crusgalli (T2), rice with E. crusgali var. zelayensis (T3) and rice with E. colonum (T4). The results showed that T1, T2, T3 and T4 treatments reduced the Liangyoupeijiu yield by 13.8%, 10.6%, 23.8% and 0.5%, but the corresponding yield loss of Nanjing 9108 could reach up to 45.5%, 36.9%, 60.7% and 15.1%, respectively. The results above showed that T1, T2 and T3 treatments all significantly reduced grain yield, and T4 treatment only reduced grain yield for Nanjing 9108 but not for Liangyoupeijiu. All treatments elevated malondialehyde contents of rice leaf, but the activities of peroxidase, catalase, superoxide dimutase, dry matter accumulation in maturity stage, root oxidation activities and contents of indole-3-acetic acid as well as zeatin + zeatin riboside in roots during rice grain filling stage were all decreased. The influence degree of four barnyardgrass against physiological indices of rice had the order of T3 > T1 >T2 > T4. It showed that the reductions in enzyme activities of antioxidant system, root oxidation activities, contents of indole-3-acetic acid, zeatin + zeatin riboside during grain filling stage and accumulation of dry matter in maturity as well as increase in contents of malondialehyde of rice during grain filling stage might be important reasons for grain yield reduction when grew with barnyardgrass. PMID:26915195

  17. Physiological and pathological left ventricular hypertrophy of comparable degree is associated with characteristic differences of in vivo hemodynamics.

    PubMed

    Oláh, Attila; Németh, Balázs Tamás; Mátyás, Csaba; Hidi, László; Lux, Árpád; Ruppert, Mihály; Kellermayer, Dalma; Sayour, Alex Ali; Szabó, Lilla; Török, Marianna; Meltzer, Anna; Gellér, László; Merkely, Béla; Radovits, Tamás

    2016-03-01

    Left ventricular (LV) hypertrophy is a physiological or pathological response of LV myocardium to increased cardiac load. We aimed at investigating and comparing hemodynamic alterations in well-established rat models of physiological hypertrophy (PhyH) and pathological hypertrophy (PaH) by using LV pressure-volume (P-V) analysis. PhyH and PaH were induced in rats by swim training and by abdominal aortic banding, respectively. Morphology of the heart was investigated by echocardiography. Characterization of cardiac function was completed by LV P-V analysis. In addition, histological and molecular biological measurements were performed. Echocardiography revealed myocardial hypertrophy of similar degree in both models, which was confirmed by post-mortem heart weight data. In aortic-banded rats we detected subendocardial fibrosis. Reactivation of fetal gene program could be observed only in the PaH model. PhyH was associated with increased stroke volume, whereas unaltered stroke volume was detected in PaH along with markedly elevated end-systolic pressure values. Sensitive indexes of LV contractility were increased in both models, in parallel with the degree of hypertrophy. Active relaxation was ameliorated in athlete's heart, whereas it showed marked impairment in PaH. Mechanical efficiency and ventriculo-arterial coupling were improved in PhyH, whereas they remained unchanged in PaH. Myocardial gene expression of mitochondrial regulators showed marked differences between PaH and PhyH. We provided the first comparative hemodynamic characterization of PhyH and PaH in relevant rodent models. Increased LV contractility could be observed in both types of LV hypertrophy; characteristic distinction was detected in diastolic function (active relaxation) and mechanoenergetics (mechanical efficiency), which might be explained by mitochondrial differences. PMID:26718969

  18. Physiological regulation of evaporative water loss in endotherms: is the little red kaluta (Dasykaluta rosamondae) an exception or the rule?

    PubMed

    Withers, Philip C; Cooper, Christine E

    2014-06-01

    It is a central paradigm of comparative physiology that the effect of humidity on evaporative water loss (EWL) is determined for most mammals and birds, in and below thermoneutrality, essentially by physics and is not under physiological regulation. Fick's law predicts that EWL should be inversely proportional to ambient relative humidity (RH) and linearly proportional to the water vapour pressure deficit (Δwvp) between animal and air. However, we show here for a small dasyurid marsupial, the little kaluta (Dasykaluta rosamondae), that EWL is essentially independent of RH (and Δwvp) at low RH (as are metabolic rate and thermal conductance). These results suggest regulation of a constant EWL independent of RH, a hitherto unappreciated capacity of endothermic vertebrates. Independence of EWL from RH conserves water and heat at low RH, and avoids physiological adjustments to changes in evaporative heat loss such as thermoregulation. Re-evaluation of previously published data for mammals and birds suggests that a lesser dependence of EWL on RH is observed more commonly than previously thought, suggesting that physiological independence of EWL of RH is not just an unusual capacity of a few species, such as the little kaluta, but a more general capability of many mammals and birds. PMID:24741015

  19. Physiological regulation of evaporative water loss in endotherms: is the little red kaluta (Dasykaluta rosamondae) an exception or the rule?

    PubMed Central

    Withers, Philip C.; Cooper, Christine E.

    2014-01-01

    It is a central paradigm of comparative physiology that the effect of humidity on evaporative water loss (EWL) is determined for most mammals and birds, in and below thermoneutrality, essentially by physics and is not under physiological regulation. Fick's law predicts that EWL should be inversely proportional to ambient relative humidity (RH) and linearly proportional to the water vapour pressure deficit (Δwvp) between animal and air. However, we show here for a small dasyurid marsupial, the little kaluta (Dasykaluta rosamondae), that EWL is essentially independent of RH (and Δwvp) at low RH (as are metabolic rate and thermal conductance). These results suggest regulation of a constant EWL independent of RH, a hitherto unappreciated capacity of endothermic vertebrates. Independence of EWL from RH conserves water and heat at low RH, and avoids physiological adjustments to changes in evaporative heat loss such as thermoregulation. Re-evaluation of previously published data for mammals and birds suggests that a lesser dependence of EWL on RH is observed more commonly than previously thought, suggesting that physiological independence of EWL of RH is not just an unusual capacity of a few species, such as the little kaluta, but a more general capability of many mammals and birds. PMID:24741015

  20. Characteristics of Water Ingress in Norwegian Subsea Tunnels

    NASA Astrophysics Data System (ADS)

    Nilsen, Bjørn

    2014-05-01

    Water ingress represents one of the main challenges in subsea tunnelling, particularly when this occurs in sections with poor rock mass quality. This paper is discussing the main characteristics of water ingress in subsea hard rock tunnels based on the experience from almost 50 such tunnels that have been built in Norway. Following a brief description of the geological conditions and the basic design of the subsea tunnels, pre-construction investigations and investigations during excavation are discussed with particular emphasis on prediction of water ingress. Two cases with particularly difficult conditions; the Bjorøy tunnel and the Atlantic Ocean tunnel, are discussed in detail. In these cases, large water inflow with pressure of up to 2.4 MPa was encountered at major faults/weakness zones during excavation, and special procedures were required to cope with the problems. Based on the experience from the Norwegian projects, it is concluded that continuous follow-up by experienced engineering geologists, probe drilling with the drilling jumbo and pre-grouting where required are the most important factors for coping with water ingress and ensuring stability.

  1. Absorption characteristics of optically complex inland waters: Implications for water optical classification

    NASA Astrophysics Data System (ADS)

    Shi, Kun; Li, Yunmei; Li, Lin; Lu, Heng

    2013-06-01

    Multiple bio-optical measurements were conducted in inland waters of China, including Lake Taihu [spring and autumn], Lake Chaohu, Lake Dianchi, and Three Gorges Reservoirs. The variations in the absorption characteristics of chromophoric dissolved organic matter (CDOM), phytoplankton, and non-algal particles (NAP) and their relative contributions to total absorption among these waters were analyzed. The obtained results indicated that these areas are representative of the optically complex inland waters characterized by strong regional variations of their absorption properties. By means of the relative contributions of NAP and phytoplankton to the total water absorption at 550 and 675 nm, these waters were classified into three optical water types, each one having specific biogeochemical and optical properties. Two of the types were distinct and corresponded to waters that are optically controlled by NAP (Type I) and dominated by phytoplankton (Type III). Type II was related to relatively optically mixed waters where the absorption properties are controlled by NAP and phytoplankton. Additionally, the differences in remote-sensing reflectance (Rrs) spectra among the three classified water types were clarified to establish optical criteria for identifying these water types. On this basis, the classification criteria for MERIS images were developed, which allowed one to cluster every Rrs spectrum into one of the three water types by comparing the values from band 6, band 8, and band 9 of MERIS images. The proposed criteria were subsequently conducted to map the water types of Lake Taihu using MERIS images.

  2. Identification of Water Use Strategies at Early Growth Stages in Durum Wheat from Shoot Phenotyping and Physiological Measurements

    PubMed Central

    Nakhforoosh, Alireza; Bodewein, Thomas; Fiorani, Fabio; Bodner, Gernot

    2016-01-01

    Modern imaging technology provides new approaches to plant phenotyping for traits relevant to crop yield and resource efficiency. Our objective was to investigate water use strategies at early growth stages in durum wheat genetic resources using shoot imaging at the ScreenHouse phenotyping facility combined with physiological measurements. Twelve durum landraces from different pedoclimatic backgrounds were compared to three modern check cultivars in a greenhouse pot experiment under well-watered (75% plant available water, PAW) and drought (25% PAW) conditions. Transpiration rate was analyzed for the underlying main morphological (leaf area duration) and physiological (stomata conductance) factors. Combining both morphological and physiological regulation of transpiration, four distinct water use types were identified. Most landraces had high transpiration rates either due to extensive leaf area (area types) or both large leaf areas together with high stomata conductance (spender types). All modern cultivars were distinguished by high stomata conductance with comparatively compact canopies (conductance types). Only few landraces were water saver types with both small canopy and low stomata conductance. During early growth, genotypes with large leaf area had high dry-matter accumulation under both well-watered and drought conditions compared to genotypes with compact stature. However, high stomata conductance was the basis to achieve high dry matter per unit leaf area, indicating high assimilation capacity as a key for productivity in modern cultivars. We conclude that the identified water use strategies based on early growth shoot phenotyping combined with stomata conductance provide an appropriate framework for targeted selection of distinct pre-breeding material adapted to different types of water limited environments. PMID:27547208

  3. Effect of drinking water temperature on physiological variables of crossbred dairy cattle at high altitude temperate region of Himalayas

    PubMed Central

    Golher, D. M.; Thirumurugan, P.; Patel, B. H. M.; Upadhyay, V. K.; Sahu, S.; Gaur, G. K.; Bhoite, S. H.

    2015-01-01

    Aim: The objective of study was to investigate the effects of drinking water on certain physiological parameters such as heart rate (HR), respiration rate (RR), rectal temperature (RT) and, ruminal motility (RM). Materials and Methods: The experiment was carried out on 18 farm bred lactating crossbred cows. The animals selected for the study were divided into three groups of six animals each on the basis of milk yield and parity and were allotted to three treatment group of six each such as ambient drinking water temperature at 10.25±0.28°C (ambient water, T1), drinking water temperature at 15-20°C (T2) and drinking water temperature at 35-40°C (T3). All the managemental practices were kept similar during experiment except drinking water temperatures physiological variables such as HR, RR, RT, and RM of the individual cow was measured and recorded twice in a day at 800 h and again at 1400 h two consecutive days in a week 15 min after providing drinking water. Result: HR and RR at morning and at evening recorded were within the normal physiological level for all the treatment groups. However, RT at morning was comparable in all the treatments whereas at evening it was significantly (p<0.01) higher for cows consuming in T2 and in T3 than cows consumed (T1). The RM during morning among the treatments were non-significant as compared to the rumen motility at evening was significantly higher for (T1) and (T2) than for cows in (T3). Conclusion: It can be concluded that offering warm drinking water at 35-40°C to crossbred lactating dairy cow is beneficial during winter at high altitude temperate region. PMID:27047019

  4. Identification of Water Use Strategies at Early Growth Stages in Durum Wheat from Shoot Phenotyping and Physiological Measurements.

    PubMed

    Nakhforoosh, Alireza; Bodewein, Thomas; Fiorani, Fabio; Bodner, Gernot

    2016-01-01

    Modern imaging technology provides new approaches to plant phenotyping for traits relevant to crop yield and resource efficiency. Our objective was to investigate water use strategies at early growth stages in durum wheat genetic resources using shoot imaging at the ScreenHouse phenotyping facility combined with physiological measurements. Twelve durum landraces from different pedoclimatic backgrounds were compared to three modern check cultivars in a greenhouse pot experiment under well-watered (75% plant available water, PAW) and drought (25% PAW) conditions. Transpiration rate was analyzed for the underlying main morphological (leaf area duration) and physiological (stomata conductance) factors. Combining both morphological and physiological regulation of transpiration, four distinct water use types were identified. Most landraces had high transpiration rates either due to extensive leaf area (area types) or both large leaf areas together with high stomata conductance (spender types). All modern cultivars were distinguished by high stomata conductance with comparatively compact canopies (conductance types). Only few landraces were water saver types with both small canopy and low stomata conductance. During early growth, genotypes with large leaf area had high dry-matter accumulation under both well-watered and drought conditions compared to genotypes with compact stature. However, high stomata conductance was the basis to achieve high dry matter per unit leaf area, indicating high assimilation capacity as a key for productivity in modern cultivars. We conclude that the identified water use strategies based on early growth shoot phenotyping combined with stomata conductance provide an appropriate framework for targeted selection of distinct pre-breeding material adapted to different types of water limited environments. PMID:27547208

  5. Thrust Characteristics of Water Rocket and Their Improvement

    NASA Astrophysics Data System (ADS)

    Watanabe, Rikio; Tomita, Nobuyuki; Takemae, Toshiaki

    The propulsive characteristics of water rockets are analyzed theoretically and experimentally. The unsteady thrust force acting on a PET bottle and the air pressure inside the bottle are measured simultaneously by the thrust test stand we have developed. The semi-empirical thrust history is obtained utilizing the air pressure history and it is compared with the measured thrust history. The results show qualitative agreement. The observation of the flow inside bottle by a high-speed video camera shows that the air precedes water when it is about to be discharged entirely. We have developed a flow regulator attached to the nozzle cap to reduce the precursor air discharge that is considered as a result of the swirling flow inside the bottle. The experimental results show that the air discharge and the body vibration are suppressed effectively.

  6. Human Adult Retinal Pigment Epithelial Stem Cell–Derived RPE Monolayers Exhibit Key Physiological Characteristics of Native Tissue

    PubMed Central

    Blenkinsop, Timothy A.; Saini, Janmeet S.; Maminishkis, Arvydas; Bharti, Kapil; Wan, Qin; Banzon, Tina; Lotfi, Mostafa; Davis, Janine; Singh, Deepti; Rizzolo, Lawrence J.; Miller, Sheldon; Temple, Sally; Stern, Jeffrey H.

    2015-01-01

    Purpose We tested what native features have been preserved with a new culture protocol for adult human RPE. Methods We cultured RPE from adult human eyes. Standard protocols for immunohistochemistry, electron microscopy, electrophysiology, fluid transport, and ELISA were used. Results Confluent monolayers of adult human RPE cultures exhibit characteristics of native RPE. Immunohistochemistry demonstrated polarized expression of RPE markers. Electron microscopy illustrated characteristics of native RPE. The mean transepithelial potential (TEP) was 1.19 ± 0.24 mV (mean ± SEM, n = 31), apical positive, and the mean transepithelial resistance (RT) was 178.7 ± 9.9 Ω·cm2 (mean ± SEM, n = 31). Application of 100 μM adenosine triphosphate (ATP) apically increased net fluid absorption (Jv) by 6.11 ± 0.53 μL·cm2·h−1 (mean ± SEM, n = 6) and TEP by 0.33 ± 0.048 mV (mean ± SEM, n = 25). Gene expression of cultured RPE was comparable to native adult RPE (n = 5); however, native RPE RNA was harvested between 24 and 40 hours after death and, therefore, may not accurately reflect healthy native RPE. Vascular endothelial growth factor secreted preferentially basally 2582 ± 146 pg/mL/d, compared to an apical secretion of 1548 ± 162 pg/mL/d (n = 14, P < 0.01), while PEDF preferentially secreted apically 1487 ± 280 ng/mL/d compared to a basolateral secretion of 864 ± 132 ng/mL/d (n = 14, P < 0.01). Conclusions The new culture model preserves native RPE morphology, electrophysiology, and gene and protein expression patterns, and may be a useful model to study RPE physiology, disease, and transplantation. PMID:26540654

  7. Fusarium toxin-contaminated maize in diets of growing bulls: effects on performance, slaughtering characteristics, and transfer into physiological liquids.

    PubMed

    Winkler, Janine; Gödde, Jens; Meyer, Ulrich; Frahm, Jana; Westendarp, Heiner; Dänicke, Sven

    2016-08-01

    The present feeding study was carried out to examine the effects of Fusarium toxin-contaminated diets on performance and slaughtering characteristics and on the transfer of the Fusarium toxins zearalenone (ZEN), deoxynivalenol (DON) and their metabolites into physiological matrices. A total of 61 bulls (483 ± 46 kg) were fed with graded proportions of Fusarium toxin-contaminated feed over a period of 10 weeks. The total mixed rations (TMR) consisted of 47 % grass silage, 20 % press pulp silage, and 33 % concentrate on dry matter (DM) basis. Increasing toxin concentrations were achieved by the exchange of control maize with Fusarium toxin-contaminated maize in the concentrates. Thus, dietary toxin concentrations between 0.08 and 0.69 mg ZEN and 0.36 and 8.31 mg DON per kg DM were covered by the four feeding groups. Based on increasing DM intake with increasing mycotoxin contaminations of the diet, the live weight gain and energy intake differed significantly between the groups. No effects were observed on slaughtering characteristics and organ weights. ZEN, α-zeralenol, β-zeralenol (β-ZEL), zeralanone, α-zearalanol, β-zearalanol, DON, and de-deepoxy-DON (de-DON) were simultaneously determined in urine, plasma, and liquor whereby quantifiable concentrations of ZEN, β-ZEL, DON, and de-DON were found in urine, of DON and de-DON in plasma, and solely of de-DON in liquor. Based on overall results it can be concluded that current EU-guidance values for critical concentrations of DON and ZEN can be regarded as safe levels also for growing bulls. Urine and blood toxin residue levels can be used to assess exposure of bulls. PMID:27083899

  8. Physiological Characteristics and Production of Folic Acid of Lactobacillus plantarum JA71 Isolated from Jeotgal, a Traditional Korean Fermented Seafood

    PubMed Central

    Lim, Sang-Dong

    2014-01-01

    Folic acid, one of the B group of vitamins, is an essential substance for maintaining the functions of the nervous system, and is also known to decrease the level of homocysteine in plasma. Homocysteine influences the lowering of the cognitive function in humans, and especially in elderly people. In order to determine the strains with a strong capacity to produce folic acid, 190 bacteria were isolated from various kinds of jeotgal and chungkuk-jang. In our test experiment, JA71 was found to contain 9.03μg/mL of folic acid after 24 h of incubation in an MRS broth. This showed that JA71 has the highest folic acid production ability compared to the other lactic acid bacteria that were isolated. JA71 was identified as Lactobacillus plantarum by the result of API carbohydrate fermentation pattern and 16s rDNA sequence. JA71 was investigated for its physiological characteristics. The optimum growth temperature of JA71 was 37℃, and the cultures took 12 h to reach pH 4.4. JA71 proved more sensitive to bacitracin when compared with fifteen different antibiotics, and showed most resistance to neomycin and vancomycin. Moreover, it was comparatively tolerant of bile juice and acid, and displayed resistance to Escherichia coli, Salmonella Typhimurium, and Staphylococcus aureus with restraint rates of 60.4%, 96.7%, and 76.2%, respectively. These results demonstrate that JA71 could be an excellent strain for application to functional products. PMID:26760752

  9. Physiological Characteristics and Production of Folic Acid of Lactobacillus plantarum JA71 Isolated from Jeotgal, a Traditional Korean Fermented Seafood.

    PubMed

    Park, Sun-Young; Do, Jeong-Ryong; Kim, Young-Jin; Kim, Kee-Sung; Lim, Sang-Dong

    2014-01-01

    Folic acid, one of the B group of vitamins, is an essential substance for maintaining the functions of the nervous system, and is also known to decrease the level of homocysteine in plasma. Homocysteine influences the lowering of the cognitive function in humans, and especially in elderly people. In order to determine the strains with a strong capacity to produce folic acid, 190 bacteria were isolated from various kinds of jeotgal and chungkuk-jang. In our test experiment, JA71 was found to contain 9.03μg/mL of folic acid after 24 h of incubation in an MRS broth. This showed that JA71 has the highest folic acid production ability compared to the other lactic acid bacteria that were isolated. JA71 was identified as Lactobacillus plantarum by the result of API carbohydrate fermentation pattern and 16s rDNA sequence. JA71 was investigated for its physiological characteristics. The optimum growth temperature of JA71 was 37℃, and the cultures took 12 h to reach pH 4.4. JA71 proved more sensitive to bacitracin when compared with fifteen different antibiotics, and showed most resistance to neomycin and vancomycin. Moreover, it was comparatively tolerant of bile juice and acid, and displayed resistance to Escherichia coli, Salmonella Typhimurium, and Staphylococcus aureus with restraint rates of 60.4%, 96.7%, and 76.2%, respectively. These results demonstrate that JA71 could be an excellent strain for application to functional products. PMID:26760752

  10. The Effect of Phenazine-1-Carboxylic Acid on the Morphological, Physiological, and Molecular Characteristics of Phellinus noxius.

    PubMed

    Huang, Huazhi; Sun, Longhua; Bi, Keke; Zhong, Guohua; Hu, Meiying

    2016-01-01

    In this study, the effect of phenazine-1-carboxylic acid (PCA) on morphological, physiological, and molecular characteristics of Phellinus noxius has been investigated, and the potential antifungal mechanism of PCA against P. noxius was also explored. The results revealed that PCA showed in vitro antifungal potential against P. noxius and completely inhibited P. noxius hyphae at concentrations >40 μg/mL. PCA inhibited both mycelial growth and the loss of mycelial biomass in vitro in a dose-dependent manner. Morphological changes in PCA-treated P. noxius hyphae, such as irregularly swollen mycelia as well as short hyphae with increased septation and less branching, were observed by optical microscopy. The intracellular reactive oxygen species (ROS) levels were significantly increased in PCA-treated P. noxius cells as compared to control groups. Induced hyperpolarization of the mitochondrial membrane potential (MMP), repressed superoxide dismutase (SOD) activity and up-regulated gene expression of seven tested genes were also found in PCA-treated P. noxius groups. Thus, the present results suggested that the mechanism of action of PCA against P. noxius might be attributed to direct damage of mycelium and high intracellular ROS production, and indirect induction of genes involved in cell detoxification, oxidation-reduction process, and electron transport of the respiratory chain. PMID:27187325

  11. Basic anatomical and physiological data for use in radiological protection: reference values. A report of age- and gender-related differences in the anatomical and physiological characteristics of reference individuals. ICRP Publication 89.

    PubMed

    2002-01-01

    This report presents detailed information on age- and gender-related differences in the anatomical and physiological characteristics of reference individuals. These reference values provide needed input to prospective dosimetry calculations for radiation protection purposes for both workers and members of the general public. The purpose of this report is to consolidate and unify in one publication, important new information on reference anatomical and physiological values that has become available since Publication 23 was published by the ICRP in 1975. There are two aspects of this work. The first is to revise and extend the information in Publication 23 as appropriate. The second is to provide additional information on individual variation among grossly normal individuals resulting from differences in age, gender, race, or other factors. This publication collects, unifies, and expands the updated ICRP reference values for the purpose of providing a comprehensive and consistent set of age- and gender-specific reference values for anatomical and physiological features of the human body pertinent to radiation dosimetry. The reference values given in this report are based on: (a) anatomical and physiological information not published before by the ICRP; (b) recent ICRP publications containing reference value information; and (c) information in Publication 23 that is still considered valid and appropriate for radiation protection purposes. Moving from the past emphasis on 'Reference Man', the new report presents a series of reference values for both male and female subjects of six different ages: newborn, 1 year, 5 years, 10 years, 15 years, and adult. In selecting reference values, the Commission has used data on Western Europeans and North Americans because these populations have been well studied with respect to antomy, body composition, and physiology. When appropriate, comparisons are made between the chosen reference values and data from several Asian populations

  12. Relationship between characteristics of water polo players and efficacy indices.

    PubMed

    Alcaraz, Pedro E; Abraldes, J Arturo; Ferragut, Carmen; Vila, Helena; Rodríguez, Nuria; Argudo, Francisco M

    2012-07-01

    The aim of this study was to define and examine the relationships between the anthropometrical characteristics, maximum isometric grip strength, and competition throwing velocities and efficacy indices in high-level water polo player. Eleven elite trained male water polo players participated in this study. During preseason training, the following measures were taken: standard anthropometry (height, body mass, arm spam, skinfolds, body girths, and skeletal breadths) and grip strength. During official European Competitions (n = 7), efficacy indices (offensives: shot definition, resolution, precision, blocked and defensives: shot resolution when defending and shots stopped when defending), average and maximum throwing velocities from all the participants by zones and in some offensive tactical phases (even, counterattacks and power play) were also determined. Throwing velocities were different (p ≤ 0.05) between some of the offensive tactical phases (even = 17.9 ± 2.4 vs. power play = 16.7 ± 2.6 m·s(-1)). In addition, significant correlations were found between competitive throwing velocities and different offensive efficacy indices. We concluded that there were significant correlations between conditioning and performance variables with anthropometrical characteristics and offensive tactical indices (blocked shots received and shot precision). Coaches should pay attention to these indices for the development of performance throughout the season. PMID:22728942

  13. Within-catchment variation in regulation of water use by eucalypts, and the roles of stomatal anatomy and physiology

    NASA Astrophysics Data System (ADS)

    Gharun, Mana; Turnbull, Tarryn; Adams, Mark

    2014-05-01

    Understanding how environmental cues impact water use of forested catchments is crucial for accurate calculation of water balance and effective catchment management in terrestrial ecosystems. We characterised structural and physiological properties of leaves and canopies of Eucalyptus delegatensis, E. pauciflora and E. radiata, the most common species in high-country catchments in temperate Australia. These properties were related to whole-tree water transport to assess differences in water use strategies among the three species. Stomatal conductance, instantaneous transpiration efficiency, stomatal occlusion (through cuticular ledges) and leaf area index differed significantly among species. Whole-tree water use of all species was strongly coupled to changes in vapour pressure deficit (VPD) and photosynthetically active radiation (Q), yet stomatal closure reduced water transport at VPD > 1 kPa in all species, even when soil water was not limiting. The observed differences in leaf traits and related water use strategies reflect species-specific adaptations to dominant environmental conditions within the landscape matrix of catchments. The generalist E. radiata seems to follow an opportunistic, while the two more spatially restricted species have adopted a pessimistic water use strategy. Catchment-scale models of carbon and water fluxes will need to reflect such variation in structure and function, if they are to fully capture species effects on water balance and yield.

  14. Spectral characteristics analysis of red tide water in mesocosm experiment

    NASA Astrophysics Data System (ADS)

    Cui, Tingwei; Zhang, Jie; Zhang, Hongliang; Ma, Yi; Gao, Xuemin

    2003-05-01

    Mesocosm ecosystem experiment with seawater enclosed of the red tide was carried out from July to September 2001. We got four species of biology whose quantities of bion are dominant in the red tide. During the whole process from the beginning to their dying out for every specie, in situ spectral measurements were carried out. After data processing, characteristic spectra of red tide of different dominant species are got. Via comparison and analysis of characteristics of different spectra, we find that in the band region between 685 and 735 nanometers, spectral characteristics of red tide is apparently different from that of normal water. Compared to spectra of normal water, spectra of red tide have a strong reflectance peak in the above band region. As to spectra of red tide dominated by different species, the situations of reflectance peaks are also different: the second peak of Mesodinium rubrum spectrum lies between 726~732 nm, which is more than 21nm away from the other dominant species spectra"s Leptocylindrus danicus"s second spectral peak covers 686~694nm; that of Skeletonema costatum lies between 691~693 nm. Chattonella marina"s second spectral peak lies about 703~705 nm. Thus we can try to determine whether red tide has occurred according to its spectral data. In order to monitor the event of red tide and identify the dominant species by the application of the technology of hyperspectral remote sensing, acquiring spectral data of different dominant species of red tide as much as possible becomes a basic work to be achieved for spectral matching, information extraction and so on based on hyperspectral data.

  15. Sensitivity of Terrestrial Water and Energy Budgets to CO2-Physiological Forcing: An Investigation Using an Offline Land Model

    NASA Technical Reports Server (NTRS)

    Gopalakrishnan, Ranjith; Bala, Govindsamy; Jayaraman, Mathangi; Cao, Long; Nemani, Ramakrishna; Ravindranath, N. H.

    2011-01-01

    Increasing concentrations of atmospheric carbon dioxide (CO2) influence climate by suppressing canopy transpiration in addition to its well-known greenhouse gas effect. The decrease in plant transpiration is due to changes in plant physiology (reduced opening of plant stomata). Here, we quantify such changes in water flux for various levels of CO2 concentrations using the National Center for Atmospheric Research s (NCAR) Community Land Model. We find that photosynthesis saturates after 800 ppmv (parts per million, by volume) in this model. However, unlike photosynthesis, canopy transpiration continues to decline at about 5.1% per 100 ppmv increase in CO2 levels. We also find that the associated reduction in latent heat flux is primarily compensated by increased sensible heat flux. The continued decline in canopy transpiration and subsequent increase in sensible heat flux at elevated CO2 levels implies that incremental warming associated with the physiological effect of CO2 will not abate at higher CO2 concentrations, indicating important consequences for the global water and carbon cycles from anthropogenic CO2 emissions. Keywords: CO2-physiological effect, CO2-fertilization, canopy transpiration, water cycle, runoff, climate change 1.

  16. Molecular mechanisms underlying the physiological responses of the cold-water coral Desmophyllum dianthus to ocean acidification

    NASA Astrophysics Data System (ADS)

    Carreiro-Silva, M.; Cerqueira, T.; Godinho, A.; Caetano, M.; Santos, R. S.; Bettencourt, R.

    2014-06-01

    Cold-water corals (CWCs) are thought to be particularly vulnerable to ocean acidification (OA) due to increased atmospheric pCO2, because they inhabit deep and cold waters where the aragonite saturation state is naturally low. Several recent studies have evaluated the impact of OA on organism-level physiological processes such as calcification and respiration. However, no studies to date have looked at the impact at the molecular level of gene expression. Here, we report results of a long-term, 8-month experiment to compare the physiological responses of the CWC Desmophyllum dianthus to OA at both the organismal and gene expression levels under two pCO2/pH treatments: ambient pCO2 (460 μatm, pHT = 8.01) and elevated pCO2 (997 μatm, pHT = 7.70). At the organismal level, no significant differences were detected in the calcification and respiration rates of D. dianthus. Conversely, significant differences were recorded in gene expression profiles, which showed an up-regulation of genes involved in cellular stress (HSP70) and immune defence (mannose-binding c-type lectin). Expression of alpha-carbonic anhydrase, a key enzyme involved in the synthesis of coral skeleton, was also significantly up-regulated in corals under elevated pCO2, indicating that D. dianthus was under physiological reconditioning to calcify under these conditions. Thus, gene expression profiles revealed physiological impacts that were not evident at the organismal level. Consequently, understanding the molecular mechanisms behind the physiological processes involved in a coral's response to elevated pCO2 is critical to assess the ability of CWCs to acclimate or adapt to future OA conditions.

  17. Life under water: physiological adaptations to diving and living at sea.

    PubMed

    Castellini, Michael

    2012-07-01

    This review covers the field of diving physiology by following a chronological approach and focusing heavily on marine mammals. Because the study of modern diving physiology can be traced almost entirely to the work of Laurence Irving in the 1930s, this particular field of physiology is different than most in that it did not derive from multiple laboratories working at many locations or on different aspects of a similar problem. Because most of the physiology principles still used today were first formulated by Irving, it is important to the study of this field that the sequence of thought is examined as a progression of theory. The review covers the field in roughly decadal blocks and traces ideas as they were first suggested, tested, modified and in some cases, abandoned. Because diving physiology has also been extremely dependent on new technologies used in the development of diving recorders, a chronological approach fits well with advances in electronics and mechanical innovation. There are many species that dive underwater as part of their natural behavior, but it is mainly the marine mammals (seals, sea lions, and whales) that demonstrate both long duration and dives to great depth. There have been many studies on other diving species including birds, snakes, small aquatic mammals, and humans. This work examines these other diving species as appropriate and a listing of reviews and relevant literature on these groups is included at the end. PMID:23723028

  18. Definition and characteristics of the water abundant season in Korea

    NASA Astrophysics Data System (ADS)

    Park, So-Ra; Oh, Su-Bin; Byun, Hi-Ryong

    2015-04-01

    In contrast to the normal seasons that are classified by the distribution of temperature and precipitation, this study defines a new concept of the water abundant season (WAS) when water is more abundant than in other seasons. We investigated its characteristics on 60 stations in Korea, and compared it with Changma (the rainy season). In this study, Available Water Resources Index (AWRI), which is a summed daily precipitation accumulated for more than 365 days with a time-dependent reduction function and reflects the current water condition, was used to quantify the water amount. In addition, the median value of 30 year's daily AWRI was used as the criterion value dividing WAS from other seasons. The results show that the terminologies on water resources have changed from qualitative concepts such as abundance, deficit, and continuous rainfall, to quantitative values using AWRI. In detail, it was known that the WAS in Korea starts on 2 July and ends on 25 December, lasting for 176 days. The onset date of WAS in Korea is getting earlier, with a trend of 2.9 days/decade. The end date does later with a delay of 7.5 days/decade, and the duration is increasing at 10.4 days/decade. We looked at the WAS by stations and saw, on average, that 14 June was the earliest onset date in Seogwipo and 29 July was the latest one in Sokcho, representing a difference of 45 days. The earliest end date was in Tongyeong at 5 December and the latest one is in Uljin at 16 January of the following year, a difference of 41 days. Tongyeong had the shortest (166 days) WAS duration and Uljin had the longest (207 days) on average. The big spatial differences of the criterion values per station were detected and quantified. The largest criterion value for WAS were recorded in Seongsan with 270.7 mm, which is almost double of the smallest value, which was recorded in Uiseong (135.9 mm). Comparing WAS with the Changma (the rainy season in Korea) showed that the onset date of WAS is close to that of

  19. Physiological impacts of ABA-JA interactions under water-limitation.

    PubMed

    de Ollas, Carlos; Dodd, Ian C

    2016-08-01

    Plant responses to drought stress depend on highly regulated signal transduction pathways with multiple interactions. This complex crosstalk can lead to a physiological outcome of drought avoidance or tolerance/resistance. ABA is the principal mediator of these responses due to the regulation of stomatal closure that determines plant growth and survival, but also other strategies of drought resistance such as osmotic adjustment. However, other hormones such as JA seem responsible for regulating a subset of plant responses to drought by regulating ABA biosynthesis and accumulation and ABA-dependent signalling, but also by ABA independent pathways. Here, we review recent reports of ABA-JA hormonal and molecular interactions within a physiological framework of drought tolerance. Understanding the physiological significance of this complex regulation offers opportunities to find strategies of drought tolerance that avoid unwanted side effects that limit growth and yield, and may allow biotechnological crop improvement. PMID:27299601

  20. Eco-physiological response of Populus euphratica Oliv. to water release of the lower reaches of the Tarim River, China

    NASA Astrophysics Data System (ADS)

    Wang, Q.; Ruan, X.; Chen, Y. N.; Li, W. H.

    2007-10-01

    Eco-physiological and plant performance responses and acclimation of Populus euphratica Oliv. to water release of the lower reaches of Tarim River, China were investigated. Three representative areas and 15 transects were selected along the lower reaches of the Tarim River. The groundwater level and salt content as well as plant performance and the contents of proline, soluble sugar, and plant endogenous hormone (ABA, CTK) in leaves were monitored and analyzed before- and after-water release. The groundwater level was raised in different areas and transects by the water release program. The physiological stress to P. euphratica decreased after the water release. Our results suggested that the groundwater level in the studied region changed from -3.15 to -4.12 m, salt content of the groundwater from 67.15 to 72.65 mM, the proline content from 9.28 to 11.06 mM, the soluble sugar content from 224.71 to 252.16 mM, the ABA content from 3.59 to 5.01 ng/(g FW), and the CK content from 4.01 to 4.56 ng/(g FW)- for the optimum growth and recover of P. euphratica indicated by the plant performance parameters, and the efficiency of water release was the highest.

  1. Characteristic mega-basin water storage behavior using GRACE

    PubMed Central

    Reager, J T; Famiglietti, James S

    2013-01-01

    [1] A long-standing challenge for hydrologists has been a lack of observational data on global-scale basin hydrological behavior. With observations from NASA’s Gravity Recovery and Climate Experiment (GRACE) mission, hydrologists are now able to study terrestrial water storage for large river basins (>200,000 km2), with monthly time resolution. Here we provide results of a time series model of basin-averaged GRACE terrestrial water storage anomaly and Global Precipitation Climatology Project precipitation for the world’s largest basins. We address the short (10 year) length of the GRACE record by adopting a parametric spectral method to calculate frequency-domain transfer functions of storage response to precipitation forcing and then generalize these transfer functions based on large-scale basin characteristics, such as percent forest cover and basin temperature. Among the parameters tested, results show that temperature, soil water-holding capacity, and percent forest cover are important controls on relative storage variability, while basin area and mean terrain slope are less important. The derived empirical relationships were accurate (0.54 ≤ Ef ≤ 0.84) in modeling global-scale water storage anomaly time series for the study basins using only precipitation, average basin temperature, and two land-surface variables, offering the potential for synthesis of basin storage time series beyond the GRACE observational period. Such an approach could be applied toward gap filling between current and future GRACE missions and for predicting basin storage given predictions of future precipitation. PMID:24563556

  2. [Complex effects of simulated acid rain and Cu on the physiological characteristics of Paulownia fortunei and its detoxification mechanism].

    PubMed

    Wang, Jiang; Zhang, Chong-Bang; Ke, Shi-Sheng; Qian, Bao-Ying

    2010-03-01

    A pot experiment was conducted to study the effects of simulated acid rain (pH 4.0, 5.0) and Cu (0-200 mg x kg(-1)) on the physiological characteristics of Paulownia fortunei and its detoxification mechanism. With no Cu addition, the leaf chlorophyll, carotenoid, O2 division by, H2O2, and MDA contents of P. fortunei had no significant differences between the two acid rain treatments. However, with the addition of 100 and 200 mg Cu x kg(-1), the chlorophyll and carotenoid contents of treatment pH 4.0 were lower, while the O2 divided by, H2O2 and MDA contents were higher thanthose of treatment pH 5.0. The chlorophyll a/b ratio of treatments Cu was higher than that of the control. The leaf Cu content decreased obviously with the increasing acidity of stimulated acid rain, but the root Cu content was in reverse. With increasing Cu addition, both the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) and the total contents of phytochelatins (PCs) and glutathione (GSH) in treatment pH 5.0 increased, while the activities of SOD, POD, CAT and APX in treatment pH 4.0 decreased after an initial increase, and the total contents of glutathione (GSH) decreased greatly in treatment 200 mg Cu x kg(-1). All of these demonstrated that the oxidative stress of high Cu concentration to P. fortunei was aggravated by stimulated acid rain. PMID:20560310

  3. The Characteristics of Sleepiness During Real Driving at Night—A Study of Driving Performance, Physiology and Subjective Experience

    PubMed Central

    Sandberg, David; Anund, Anna; Fors, Carina; Kecklund, Göran; Karlsson, Johan G.; Wahde, Mattias; Åkerstedt, Torbjörn

    2011-01-01

    Study Objectives: Most studies of sleepy driving have been carried out in driving simulators. A few studies of real driving are available, but these have used only a few sleepiness indicators. The purpose of the present study was to characterize sleepiness in several indicators during real driving at night, compared with daytime driving. Design: Participants drove 55 km (at 90km/h) on a 9-m-wide rural highway in southern Sweden. Daytime driving started at 09:00 or 11:00 (2 groups) and night driving at 01:00 or 03:00 (balanced design). Setting: Instrumented car on a real road in normal traffic. Participants: Eighteen participants drawn from the local driving license register. Interventions: Daytime and nighttime drives. Measurement and Results: The vehicle was an instrumented car with video monitoring of the edge of the road and recording of the lateral position and speed. Electroencephalography and electrooculography were recorded, together with ratings of sleepiness every 5 minutes. Pronounced effects of night driving were seen for subjective sleepiness, electroencephalographic indicators of sleepiness, blink duration, and speed. Also, time on task showed significant effects for subjective sleepiness, blink duration, lane position, and speed. Sleepiness was highest toward the end of the nighttime drive. Night driving caused a leftward shift in lateral position and a reduction of speed. The latter two findings, as well as the overall pattern of sleepiness indicators, provide new insights into the effects of night driving. Conclusion: Night driving is associated with high levels of subjective, electrophysiologic, and behavioral sleepiness. Citation: Sandberg D; Anund A; Fors C; Kecklund G; Karlsson JG; Wahde M; Åkerstedt T. The characteristics of sleepiness during real driving at night—a study of driving performance, physiology and subjective experience. SLEEP 2011;34(10):1317-1325. PMID:21966063

  4. [Effects of exogenous nitric oxide on physiological characteristics of longan (Dimocarpus longana) seedlings under acid rain stress].

    PubMed

    Liu, Jian-fu; Wang, Ming-yuan; Yang, Chen; Zhu, Ai-jun

    2013-08-01

    This paper studied the effects of exogenous nitric oxide donor sodium nitroprusside (SNP) on the chlorophyll content, antioxidant enzyme activities, and osmotic regulation substances of longan (Dimocarpus longana 'Fuyan') seedlings under acid rain (pH 3.0) stress. Under the acid rain stress, the seedling leaf superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities and chlorophyll, soluble protein and soluble sugar contents decreased obviously, while the leaf malondialdedyde content had a remarkable increase, suggesting the toxic effect of the acid rain on the seedlings. Exogenous nitric oxide had dual nature on the physiological characteristics of longan seedlings under acid rain stress. Applying 0.1-0.5 mmol x L(-1) of SNP improved the SOD, POD and CAT activities and the chlorophyll, soluble protein and soluble sugar contents significantly, and decreased the malondialdedyde content. Low concentrations SNP reduced the oxidative damage caused by the acid rain stress, and 0.5 mmol x L(-1) of SNP had the best effect. Under the application of 0.5 mmol x L(-1) of SNP, the total chlorophyll, soluble protein, and soluble sugar contents and the SOD, POD and CAT activities increased by 76.0%, 107.0%, 216.1%, 150. 0%, 350.9% and 97.1%, respectively, and the malondialdedyde content decreased by 46.4%. It was suggested that low concentration (0.1-0.5 mmol x L(-1)) SNP could alleviate the toxic effect of acid rain stress on longan seedlings via activating the leaf antioxidant enzyme activities and reducing oxidative stress, while high concentration SNP (1.0 mmol x L(-1)) lowered the mitigation effect. PMID:24380343

  5. Physiology and transcriptomics of water-deficit stress responses in wheat cultivars TAM 111 and TAM 112.

    PubMed

    Reddy, Srirama Krishna; Liu, Shuyu; Rudd, Jackie C; Xue, Qingwu; Payton, Paxton; Finlayson, Scott A; Mahan, James; Akhunova, Alina; Holalu, Srinidhi V; Lu, Nanyan

    2014-09-01

    Hard red winter wheat crops on the U.S. Southern Great Plains often experience moderate to severe drought stress, especially during the grain filling stage, resulting in significant yield losses. Cultivars TAM 111 and TAM 112 are widely cultivated in the region, share parentage and showed superior but distinct adaption mechanisms under water-deficit (WD) conditions. Nevertheless, the physiological and molecular basis of their adaptation remains unknown. A greenhouse study was conducted to understand the differences in the physiological and transcriptomic responses of TAM 111 and TAM 112 to WD stress. Whole-plant data indicated that TAM 112 used more water, produced more biomass and grain yield under WD compared to TAM 111. Leaf-level data at the grain filling stage indicated that TAM 112 had elevated abscisic acid (ABA) content and reduced stomatal conductance and photosynthesis as compared to TAM 111. Sustained WD during the grain filling stage also resulted in greater flag leaf transcriptome changes in TAM 112 than TAM 111. Transcripts associated with photosynthesis, carbohydrate metabolism, phytohormone metabolism, and other dehydration responses were uniquely regulated between cultivars. These results suggested a differential role for ABA in regulating physiological and transcriptomic changes associated with WD stress and potential involvement in the superior adaptation and yield of TAM 112. PMID:25014264

  6. Lead-leaching characteristics of submersible residential water pumps

    SciTech Connect

    Maas, R.P.; Patch, S.C.; Pope, J.; Thornton, L.

    1998-01-01

    In June 1991, the US Environmental Protection Agency set an action level of 15 micrograms per liter ({micro}g/L) for lead in drinking water and a maximum contaminant level goal of 0 {micro}g/L at the point of use. Consequently, it is important to understand the cumulative effect of lead exposure from all parts of a residential plumbing distribution system. This paper presents findings of the lead-leaching characteristics of submersible water pumps used in residential wells, which were tested under standard laboratory conditions and under actual residential usage patterns. Laboratory experiments found lead to be leaching in hundreds of {micro}g/L after 10 days of testing; when dilution factors approximating typical residential usage conditions were applied, both the laboratory and the field installation results were in the 3 to 5 {micro}g/L range after 30 days of testing. Exposures after several months were also determined, and overall, leaded-brass well pumps are concluded to represent a marginally significant source of lead exposure to the approximately 40 million Americans served by individual wells.

  7. Leaf physiology and biomass allocation of backcross hybrid American chestnut (Castanea dentata) seedlings in response to light and water availability.

    PubMed

    Brown, Caleb E; Mickelbart, Michael V; Jacobs, Douglass F

    2014-12-01

    Partial canopy cover promotes regeneration of many temperate forest trees, but the consequences of shading on seedling drought resistance are unclear. Reintroduction of blight-resistant American chestnut (Castanea dentata (Marsh.) Borkh.) into eastern North American forests will often occur on water-limited sites and under partial canopy cover. We measured leaf pre-dawn water potential (Ψpd), leaf gas exchange, and growth and biomass allocation of backcross hybrid American chestnut seedlings from three orchard sources grown under different light intensities (76, 26 and 8% full photosynthetically active radiation (PAR)) and subjected to well-watered or mid-season water-stressed conditions. Seedlings in the water-stress treatment were returned to well-watered conditions after wilting to examine recovery. Seedlings growing under medium- and high-light conditions wilted at lower leaf Ψpd than low-light seedlings. Recovery of net photosynthesis (Anet) and stomatal conductance (gs) was greater in low and medium light than in high light. Seed source did not affect the response to water stress or light level in most cases. Between 26 and 8% full PAR, light became limiting to the extent that the effects of water stress had no impact on some growth and morphological traits. We conclude that positive and negative aspects of shading on seedling drought tolerance and recovery are not mutually exclusive. Partial shade may help American chestnut tolerate drought during early establishment through effects on physiological conditioning. PMID:25428828

  8. Fog interception by Sequoia sempervirens (D. Don) crowns decouples physiology from soil water deficit.

    PubMed

    Simonin, Kevin A; Santiago, Louis S; Dawson, Todd E

    2009-07-01

    Although crown wetting events can increase plant water status, leaf wetting is thought to negatively affect plant carbon balance by depressing photosynthesis and growth. We investigated the influence of crown fog interception on the water and carbon relations of juvenile and mature Sequoia sempervirens trees. Field observations of mature trees indicated that fog interception increased leaf water potential above that of leaves sheltered from fog. Furthermore, observed increases in leaf water potential exceeded the maximum water potential predicted if soil water was the only available water source. Because field observations were limited to two mature trees, we conducted a greenhouse experiment to investigate how fog interception influences plant water status and photosynthesis. Pre-dawn and midday branchlet water potential, leaf gas exchange and chlorophyll fluorescence were measured on S. sempervirens saplings exposed to increasing soil water deficit, with and without overnight canopy fog interception. Sapling fog interception increased leaf water potential and photosynthesis above the control and soil water deficit treatments despite similar dark-acclimated leaf chlorophyll fluorescence. The field observations and greenhouse experiment show that fog interception represents an overlooked flux into the soil-plant-atmosphere continuum that temporarily, but significantly, decouples leaf-level water and carbon relations from soil water availability. PMID:19302173

  9. Saline water irrigation effects on soil salinity distribution and some physiological responses of field grown Chemlali olive.

    PubMed

    Ben Ahmed, Chedlia; Magdich, Salwa; Ben Rouina, Bechir; Boukhris, Makki; Ben Abdullah, Ferjani

    2012-12-30

    The shortage of water resources of good quality is becoming an issue in arid and semi arid regions. Per consequent, the use of water resources of marginal quality is becoming an important consideration, particularly in arid regions in Tunisia, where large quantities of saline water are used for irrigation. Nevertheless, the use of these waters in irrigated lands requires the control of soil salinity and a comprehensive analysis even beyond the area where water is applied. The aim of this study was to investigate the effects of saline water irrigation on soil salinity distribution and some physiological traits of field-grown adult olive trees (Olea europaea L. cv. Chemlali) under contrasting environmental conditions of the arid region in the south of Tunisia. The plants were subjected, over two growing seasons, to two drip irrigated treatments: fresh water (ECe=1.2 dS m(-1), FW) and saline water (ECe=7.5 dS m(-1), SW). Saline water irrigation (SW) has led to a significant increase in soil salinity. Furthermore, these results showed that soil salinity and soil moisture variations are not only dependent on water salinity level but are also controlled by a multitude of factors particularly the soil texture, the distance from the irrigation source and climatic conditions (rainfall pattern, temperature average, …). On the other hand, salt treatment reduced leaf midday water potential (LMWP), relative water content and photosynthetic activity and increased the leaf proline content, and this increase was season-dependent. Indeed, LMWP in SW plants decreased to -3.71 MPa. Furthermore, the highest level of proline in SW plants was registered during summer period (2.19 μmol/mg Fw). The proline accumulation recorded in stressed plants has allowed them to preserve appropriate leaf water status and photosynthetic activity. More to the point, this olive cultivar seems to be more sensible to soil salinity during the intense growth phase. Such tendencies would help to better

  10. Effects of longterm elevated carbon dioxide concentration, nitrogen and water availability on the physiology of loblolly pine (Pinus taeda) branches

    SciTech Connect

    Murthy, R.; Dougherty, P.M. )

    1994-06-01

    The objective of this study was to determine to what extent elevated CO[sub 2] alters carbon fixation of loblolly pine when water and nutrition are limiting. Three branches per tree were enclosed in polytene chambers and exposed to ambient, 1.5*ambient and 2*ambient levels of CO[sub 2] respectively for a 12 month period. A 2*2 factorial of nutrition and water was employed. Monthly instantaneous measures of maximum photosynthesis (amax), stomatal conductance and other physiological parameters were taken on needles. Branches exposed to 2* ambient CO[sub 2] in the fertilized and irrigated plots showed significantly higher amax values compared to the other treatment level combinations and showed no signs of acclimation. Results suggest that response to elevated CO[sub 2] levels depends greatly on whether nutrition and water are limiting.

  11. Physiological Changes in Cultured Sorghum Cells in Response to Induced Water Stress 1

    PubMed Central

    Newton, Ronald J.; Bhaskaran, Shyamala; Puryear, Jeffrey D.; Smith, Roberta H.

    1986-01-01

    Eight cultivars Sorghum bicolor (L.) Moench were grown as callus cultures under induced, prolonged water stress (8 weeks), with polyethylene glycol in the medium. Concentrations of soluble carbohydrates and organic acids in callus were measured at the end of the growth period to determine differences in response to prolonged water stress. Sucrose, glucose, fructose, and malate were the predominant solutes detected in all callus at all water potentials. All cultivars had high levels of solutes in the absence of water stress and low levels in the presence of prolonged water stress. However, at low water potentials, low levels of solutes were observed in drought-tolerant cultivar callus and high solute levels were observed in drought-susceptible cultivar callus. Estimated sucrose concentrations were significantly higher in water-stressed, susceptible cultivar callus. Large solute concentrations in susceptible cultivar callus were attributed to osmotic adjustment and/or reduced growth during water stress. PMID:16664867

  12. Structural and physiological responses of two invasive weeds, Mikania micrantha and Chromolaena odorata, to contrasting light and soil water conditions.

    PubMed

    Zhang, Ling-Ling; Wen, Da-Zhi

    2009-01-01

    To better understand the requirement of light and soil water conditions in the invasion sites of two invasive weeds, Mikania micrantha and Chromolaena odorata, we investigated their structural and physiological traits in response to nine combined treatments of light [full, medium and low irradiance (LI)] and soil water (full, medium and low field water content) conditions in three glasshouses. Under the same light conditions, most variables for both species did not vary significantly among different water treatments. Irrespective of water treatment, both species showed significant decreases in maximum light saturated photosynthetic rate (P (max)), photosynthetic nitrogen-use efficiency, and relative growth rate under LI relative to full irradiance; specific leaf area, however, increased significantly from full to LI though leaf area decreased significantly, indicating that limited light availability under extreme shade was the critical factor restricting the growth of both species. Our results also indicated that M. micrantha performed best under a high light and full soil water combination, while C. odorata was more efficient in growth under a high light and medium soil water combination. PMID:19030958

  13. Characteristics analysis for different water heads on the efficiency hill chart of Francis turbine

    NASA Astrophysics Data System (ADS)

    Wang, Z. N.; Guo, P. C.; Luo, X. Q.; Wang, Y. L.; Sun, S. H.

    2016-05-01

    Based on the test results of Francis turbine, the causes and inevitability of various hydraulic phenomena in the model combined characteristic curve for typical water heads were analyzed in this paper. the difference of the model combined characteristic curve from the low water head to the high water head is compared, and the characteristics and commonness of the model combined characteristic curve about different water head are summarized. Further, hydraulic performance and geometric features of Francis turbine are revealed by particularly analyzing model combined characteristic curves, and to provide powerful theoretical basis and definite modification direction for the hydraulic design of hydraulic turbine.

  14. Water-Landing Characteristics of a Reentry Capsule

    NASA Technical Reports Server (NTRS)

    McGehee, John R.; Hathaway, Melvin E.; Vaughan, Victor L., Jr.

    1959-01-01

    Experimental and theoretical investigations have been made to determine the water-landing characteristics of a conical-shaped reentry capsule having a segment of a sphere as the bottom. For the experimental portion of the investigation, a 1/12-scale model capsule and a full-scale capsule were tested for nominal flight paths of 65 deg and 90 deg (vertical), a range of contact attitudes from -30 deg to 30 deg, and a full-scale vertical velocity of 30 feet per second at contact. Accelerations were measured by accelerometers installed at the centers of gravity of the model and full-scale capsules. For the model test the accelerations were measured along the X-axis (roll) and Z-axis (yaw) and for the full-scale test they were measured along the X-axis (roll), Y-axis (pitch), and Z-axis (yaw). Motions and displacements of the capsules that occurred after contact were determined from high-speed motion pictures. The theoretical investigation was conducted to determine the accelerations that might occur along the X-axis when the capsule contacted the water from a 90 deg flight path at a 0 deg attitude. Assuming a rigid body, computations were made from equations obtained by utilizing the principle of the conservation of momentum. The agreement among data obtained from the model test, the full-scale test, and the theory was very good. The accelerations along the X-axis, for a vertical flight path and 0 deg attitude, were in the order of 40g. For a 65 deg flight path and 0 deg attitude, the accelerations along the X-axis were in the order of 50g. Changes in contact attitude, in either the positive or negative direction from 0 deg attitude, considerably reduced the magnitude of the accelerations measured along the X-axis. Accelerations measured along the Y- and Z-axes were relatively small at all test conditions.

  15. Physiological Traits Associated with Wheat Yield Potential and Performance under Water-Stress in a Mediterranean Environment

    PubMed Central

    del Pozo, Alejandro; Yáñez, Alejandra; Matus, Iván A.; Tapia, Gerardo; Castillo, Dalma; Sanchez-Jardón, Laura; Araus, José L.

    2016-01-01

    Different physiological traits have been proposed as key traits associated with yield potential as well as performance under water stress. The aim of this paper is to examine the genotypic variability of leaf chlorophyll, stem water-soluble carbohydrate content and carbon isotope discrimination (Δ13C), and their relationship with grain yield (GY) and other agronomical traits, under contrasting water conditions in a Mediterranean environment. The study was performed on a large collection of 384 wheat genotypes grown under water stress (WS, rainfed), mild water stress (MWS, deficit irrigation), and full irrigation (FI). The average GY of two growing seasons was 2.4, 4.8, and 8.9 Mg ha−1 under WS, MWS, and FI, respectively. Chlorophyll content at anthesis was positively correlated with GY (except under FI in 2011) and the agronomical components kernels per spike (KS) and thousand kernel weight (TKW). The WSC content at anthesis (WSCCa) was negatively correlated with spikes per square meter (SM2), but positively correlated with KS and TKW under WS and FI conditions. As a consequence, the relationships between WSCCa with GY were low or not significant. Therefore, selecting for high stem WSC would not necessary lead to genotypes of GY potential. The relationship between Δ13C and GY was positive under FI and MWS but negative under severe WS (in 2011), indicating higher water use under yield potential and MWS conditions. PMID:27458470

  16. Physiological Traits Associated with Wheat Yield Potential and Performance under Water-Stress in a Mediterranean Environment.

    PubMed

    Del Pozo, Alejandro; Yáñez, Alejandra; Matus, Iván A; Tapia, Gerardo; Castillo, Dalma; Sanchez-Jardón, Laura; Araus, José L

    2016-01-01

    Different physiological traits have been proposed as key traits associated with yield potential as well as performance under water stress. The aim of this paper is to examine the genotypic variability of leaf chlorophyll, stem water-soluble carbohydrate content and carbon isotope discrimination (Δ(13)C), and their relationship with grain yield (GY) and other agronomical traits, under contrasting water conditions in a Mediterranean environment. The study was performed on a large collection of 384 wheat genotypes grown under water stress (WS, rainfed), mild water stress (MWS, deficit irrigation), and full irrigation (FI). The average GY of two growing seasons was 2.4, 4.8, and 8.9 Mg ha(-1) under WS, MWS, and FI, respectively. Chlorophyll content at anthesis was positively correlated with GY (except under FI in 2011) and the agronomical components kernels per spike (KS) and thousand kernel weight (TKW). The WSC content at anthesis (WSCCa) was negatively correlated with spikes per square meter (SM2), but positively correlated with KS and TKW under WS and FI conditions. As a consequence, the relationships between WSCCa with GY were low or not significant. Therefore, selecting for high stem WSC would not necessary lead to genotypes of GY potential. The relationship between Δ(13)C and GY was positive under FI and MWS but negative under severe WS (in 2011), indicating higher water use under yield potential and MWS conditions. PMID:27458470

  17. Influence of different irrigation levels on the root water uptake and the physiology of root-chicory

    NASA Astrophysics Data System (ADS)

    Vandoorne, B.; Dekoninck, N.; Lutts, S.; Capelle, B.; Javaux, M.

    2009-04-01

    In the context of global warming and given recent heat waves observed in Western Europe, the relationship between the soil water status and the plant health has recently received more attention, especially for cash crops like chicory. In this study we particularly investigated the impact of soil water status on the chicory root water uptake and density and made a link with physiological and yield parameters. During five months, we imposed different irrigation levels to 10 plants of chicory (Cichorium intybus var. sativum) growing in greenhouses. Each seed, coming from an autogamous selection in this allogamous species, was sown in a column of 1.42m height and 0.4m diameter filled with yellow sand and irrigated from the bottom with Hoagland solution. On those 10 columns, we measured the distribution of soil moisture with TDR (8 columns) and ERT (2 columns) probes. Lateral windows also allowed us to follow the root growth. The column weights were also monitored in order to quantify the plant transpiration. During the experiment, several physiological indices were also followed like the gas exchange (CO2 and transpiration), the chlorophyll fluorescence, the stomatal conductance, the plastochron, and the Leaf Area Index (LAI). At the end of the experiment, the complete root length density and the water content profiles were measured. We had also a look to the osmotic potential, the pigments content and the isotopic discrimination of carbon in the leaves, which gives information about the level of stress. At a biochemical point of view, we measured the content in enzymes involves in inulin metabolism and sugars synthesis. We observed that the plants suffering from a slight water stress developed better. A simple1-D model was built which describes the root growth in function of the irrigation level and of the soil and atmospheric boundary conditions.

  18. A Comparison of Water Balance Components of a Spruce and a Beech Canopy Based on Parallel Micrometeorological and Plant Physiological Measurements

    NASA Astrophysics Data System (ADS)

    Spank, Uwe; Bernhofer, Christian; Clausnitzer, Falko; Köstner, Babara; Schwärzel, Kai; Feger, Karl-Heinz

    2010-05-01

    -third of Pn at the beech site. Ps is negligible in the spruce canopy. The statistical analyses of Pc showed a Pt of 12 % at the spruce site and 14 % at the beech site, which correspond to expectations, derived from measured sky view coefficients. In this context the important regulating role of Pt for silvicultural, ecological and hydrological issues becomes clear. The analyses of ET, T and I as well as the integration of ? to close of water balance were complex due to different scales of measurements. Which are different scales of EC measurements (used for ET) and SF measurements (used for T) as well as spatial heterogeneity of ?. To overcome the scale problem in components of ET somewhat an inverse solution of Penman's approach was used to separate T and I in the EC data. Here we found: differences in T between both canopies are caused predominately by different Wa in both canopies. However, influences due to differences of plant physiological characteristics between beeches and spruces were found to be less important. The potential water supply depends on two parameters: characteristics of soils and range of rooting zone. Therefore, soil characteristics determine water balance significantly under all climate conditions. However, the range of the rooting zone and the specifics of roots are only significant in droughts and dry periods, when water supply is restricted. Differences in interception between both canopies were found to be negligible during the growing season.

  19. Morphological and physiological responses of two coffee progenies to soil water availability.

    PubMed

    Dias, Paulo C; Araujo, Wagner L; Moraes, Gustavo A B K; Barros, Raimundo S; DaMatta, Fábio M

    2007-12-01

    Drought is a major environmental constraint affecting growth and production of coffee. The effects of water supply on growth, biomass allocation, water relations, and gas exchange in two coffee progenies representing drought-tolerant (Siriema) and drought-sensitive (Catucaí) genotypes were compared. They were grown in 12-L pots until 4-months old, when they were submitted to two watering treatments for 60 d: plants receiving either 100% transpired water (control plants) or a fraction (about 40%) of the amount of water transpired by control plants (drought-stressed plants). Under control conditions, Siriema grew faster than Catucaí. Regardless of the watering regimes and progenies, relative growth rate (RGR) was positively correlated both with net assimilation rate (NAR) and long-term water-use efficiency (WUE), but not with differences in biomass allocation. Both progenies responded to drought stress through (i) similar decreases in both RGR and NAR with marginal, if any, changes in allocation; (ii) decreases in leaf water potential, which occurred to a greater extent in Catucaí than in Siriema, even though they have showed similar abilities to adjust osmotically and elastically; (iii) similar reductions in net photosynthesis due mainly to nonstomatal factors; and (iv) decreases in transpiration rate coupled with increased long-term WUE. However, the lower transpiration rate and the higher long-term WUE as found in Siriema relative to Catucaí under control conditions persisted under drought conditions. Overall, the major differences between these progenies were largely associated with differences in plant water use, which was likely related to the improved water status of Siriema. The possible implications of selecting coffee genotypes for high WUE are discussed. PMID:17291628

  20. Does plasticity in plant physiological traits explain the rapid increase in water use efficiency? An ecohydrological modeling approach

    NASA Astrophysics Data System (ADS)

    Mastrotheodoros, Theodoros; Fatichi, Simone; Pappas, Christoforos; Molnar, Peter; Burlando, Paolo

    2016-04-01

    The rise of atmospheric CO2 concentration is expected to stimulate plant productivity by enhancing photosynthesis and reducing stomatal conductance and thus increasing plant water use efficiency (WUE) worldwide. An analysis of eddy covariance flux tower data from 21 forested ecosystems across the north hemisphere detected an unexpectedly large increase in WUE (Keenan et al, 2013), which was six times larger than the increase found by most previous studies based on controlled experiments (e.g., FACE), leaf-scale analyses, and numerical modelling. This increase could be solely attributed to the increase in atmospheric CO2 since other confounding factors were ruled out. Here, we investigate the potential contribution of plant plasticity, reflected in the temporal adjustment of major plant physiological traits, on changes in WUE using the ecohydrological model Tethys and Chloris (T&C). We hypothesize that the increase in WUE can be attributed to small variations in plant physiological traits, undetectable through observations, eventually triggered by the atmospheric CO2 increase. Data from the 21 sites in the above mentioned study are used to force the model. Simulation results with and without plasticity in the physiological traits (i.e., model parameters in our numerical experiments) are compared with the observed trends in WUE. We test several plant adaptation strategies in being effective in explaining the observed increase in WUE using a multifactorial numerical experiment in which we perturb in a systematic way selected plant parameters. Keenan, T. F., Hollinger, D. Y., Bohrer, G., Dragoni, D., Munger, J. W., Schmid, H. P., and Richardson, A. D. (2013). Increase in forest water-use efficiency as atmospheric carbon dioxide concentrations rise. Nature, 499(7458), 324-7.

  1. Sensitivity of terrestrial water and energy budgets to CO2-physiological forcing: an investigation using an offline land model

    NASA Astrophysics Data System (ADS)

    Gopalakrishnan, Ranjith; Bala, Govindsamy; Jayaraman, Mathangi; Cao, Long; Nemani, Ramakrishna; Ravindranath, N. H.

    2011-10-01

    Increasing concentrations of atmospheric carbon dioxide (CO2) influence climate by suppressing canopy transpiration in addition to its well-known greenhouse gas effect. The decrease in plant transpiration is due to changes in plant physiology (reduced opening of plant stomata). Here, we quantify such changes in water flux for various levels of CO2 concentrations using the National Center for Atmospheric Research's (NCAR) Community Land Model. We find that photosynthesis saturates after 800 ppmv (parts per million, by volume) in this model. However, unlike photosynthesis, canopy transpiration continues to decline at about 5.1% per 100 ppmv increase in CO2 levels. We also find that the associated reduction in latent heat flux is primarily compensated by increased sensible heat flux. The continued decline in canopy transpiration and subsequent increase in sensible heat flux at elevated CO2 levels implies that incremental warming associated with the physiological effect of CO2 will not abate at higher CO2 concentrations, indicating important consequences for the global water and carbon cycles from anthropogenic CO2 emissions.

  2. Brackish Eutrophic Water Treatment by Iris pseudacorus L.-Planted Microcosms: Physiological Responses of Iris pseudacorus L. to Salinity.

    PubMed

    Zhao, Huilin; Wang, Fen; Ji, Min

    2015-01-01

    Iris pseudacorus L. has been widely used in aquatic ecosystem to remove nutrient and has achieved positive effects. However, little is known regarding the nutrient-removal performance and physiological responses of I. pseudacorus for brackish eutrophic water treatment due to high nutrients combined with certain salinity levels. In this study, I. pseudacorus-planted microcosms were established to evaluate the capacity of I. pseudacorus to remove excessive nutrients from fresh (salinity 0.05%) and brackish (salinity 0.5%) eutrophic waters. The degradation of total nitrogen and ammonia nitrogen were not affected by 0.5% salinity; 0.5% salinity promoted the degradation of nitrate nitrogen while severely inhibited the degradation of total phosphorus. Additionally, 0.5% salinity was found to induce stress responses quantified by measuring six physiological indexes. Compared to 0.05% salinity, 0.5% salinity resulted in significant decreases in the chlorophyll a, b and total chlorophyll contents of I. pseudacorus which closely related to photosynthesis (p < 0.05). Furthermore, the higher proline, malondialdehyde contents and antioxidant enzyme activities were detected in I. pseudacorus exposed to 0.5% salinity, which provided protection against reactive oxygen species. The results highlight that the cellular stress assays are efficient for monitoring the health of I. pseudacorus in salinity shock-associated constructed wetlands. PMID:25529785

  3. Physiological, Ultrastructural and Proteomic Responses in the Leaf of Maize Seedlings to Polyethylene Glycol-Stimulated Severe Water Deficiency.

    PubMed

    Shao, Ruixin; Xin, Longfei; Mao, Jun; Li, Leilei; Kang, Guozhang; Yang, Qinghua

    2015-01-01

    After maize seedlings grown in full-strength Hoagland solution for 20 days were exposed to 20% polyethylene glycol (PEG)-stimulated water deficiency for two days, plant height, shoot fresh and dry weights, and pigment contents significantly decreased, whereas malondialdehyde (MDA) content greatly increased. Using transmission electron microscopy, we observed that chloroplasts of mesophyll cells in PEG-treated maize seedlings were swollen, with a disintegrating envelope and disrupted grana thylakoid lamellae. Using two-dimensional gel electrophoresis (2-DE) method, we were able to identify 22 protein spots with significantly altered abundance in the leaves of treated seedlings in response to water deficiency, 16 of which were successfully identified. These protein species were functionally classified into signal transduction, stress defense, carbohydrate metabolism, protein metabolism, and unknown categories. The change in the abundance of the identified protein species may be closely related to the phenotypic and physiological changes due to PEG-stimulated water deficiency. Most of the identified protein species were putatively located in chloroplasts, indicating that chloroplasts may be prone to damage by PEG stimulated-water deficiency in maize seedlings. Our results help clarify the molecular mechanisms of the responses of higher plants to severe water deficiency. PMID:26370980

  4. Physiological, Ultrastructural and Proteomic Responses in the Leaf of Maize Seedlings to Polyethylene Glycol-Stimulated Severe Water Deficiency

    PubMed Central

    Shao, Ruixin; Xin, Longfei; Mao, Jun; Li, Leilei; Kang, Guozhang; Yang, Qinghua

    2015-01-01

    After maize seedlings grown in full-strength Hoagland solution for 20 days were exposed to 20% polyethylene glycol (PEG)-stimulated water deficiency for two days, plant height, shoot fresh and dry weights, and pigment contents significantly decreased, whereas malondialdehyde (MDA) content greatly increased. Using transmission electron microscopy, we observed that chloroplasts of mesophyll cells in PEG-treated maize seedlings were swollen, with a disintegrating envelope and disrupted grana thylakoid lamellae. Using two-dimensional gel electrophoresis (2-DE) method, we were able to identify 22 protein spots with significantly altered abundance in the leaves of treated seedlings in response to water deficiency, 16 of which were successfully identified. These protein species were functionally classified into signal transduction, stress defense, carbohydrate metabolism, protein metabolism, and unknown categories. The change in the abundance of the identified protein species may be closely related to the phenotypic and physiological changes due to PEG-stimulated water deficiency. Most of the identified protein species were putatively located in chloroplasts, indicating that chloroplasts may be prone to damage by PEG stimulated-water deficiency in maize seedlings. Our results help clarify the molecular mechanisms of the responses of higher plants to severe water deficiency. PMID:26370980

  5. Antarctic killer whales make rapid, round-trip movements to subtropical waters: evidence for physiological maintenance migrations?

    PubMed

    Durban, J W; Pitman, R L

    2012-04-23

    Killer whales (Orcinus orca) are important predators in high latitudes, where their ecological impact is mediated through their movements. We used satellite telemetry to provide the first evidence of migration for killer whales, characterized by fast (more than 12 km h(-1), 6.5 knots) and direct movements away from Antarctic waters by six of 12 type B killer whales tagged when foraging near the Antarctic Peninsula, including all tags transmitting for more than three weeks. Tags on five of these whales revealed consistent movements to subtropical waters (30-37° S) off Uruguay and Brazil, in surface water temperatures ranging from -1.9°C to 24.2°C; one 109 day track documented a non-stop round trip of almost 9400 km (5075 nmi) in just 42 days. Although whales travelled slower in the warmest waters, there was no obvious interruption in swim speed or direction to indicate calving or prolonged feeding. Furthermore, these movements were aseasonal, initiating over 80 days between February and April; one whale returned to within 40 km of the tagging site at the onset of the austral winter in June. We suggest that these movements may represent periodic maintenance migrations, with warmer waters allowing skin regeneration without the high cost of heat loss: a physiological constraint that may also affect other whales. PMID:22031725

  6. Physiological acclimation of a desert antelope, Arabian oryx (Oryx leucoryx), to long-term food and water restriction.

    PubMed

    Ostrowski, Stéphane; Williams, Joseph B; Mésochina, Pascal; Sauerwein, Helga

    2006-03-01

    Desert mammals often experience scarcity of drinking water and food for prolonged periods. In this study, the first long-term acclimation experiment in a non-domesticated desert-adapted ungulate, we investigated the mechanisms used by the Arabian oryx Oryx leucoryx, to adjust its physiology to progressive food and water restriction over 5 months, an experimental regimen and time course chosen to mimic what it typically experiences between spring and late summer in the desert. At the end of the acclimation period, oryx consumed less than one and half of food and water of animals in the control group and lost 8.2+/-2.6% of their initial body mass. Experimental animals reduced their mass-specific resting metabolic rate (RMR) and total evaporative water loss (TEWL) by 16.2 and 25.7%, respectively, and maintained a digestive efficiency of about 70%. We found no support for the idea that reduced RMR in oryx correlated with a decreased thyroid hormone concentration in plasma. At the end of the 5 months acclimation, oryx continued to mobilize fatty acids to fuel metabolism, and did not use protein breakdown as a major source of gluconeogenesis. Oryx in the experimental group reduced their water intake by 70% and maintained constant plasma osmolality. They adjusted their water budget by reducing mass-specific TEWL, increasing urine osmolality and reducing urine volume by 40%, and excreting feces with <50% water content. Oryx have an unusually low TEWL compared with other arid-zone ungulates; both hydrated and water-deprived individuals have TEWL values, 51.7 and 39.3%, respectively, of allometric predictions for arid-zone ungulates. PMID:16283332

  7. Physiological integration modifies δ15N in the clonal plant Fragaria vesca, suggesting preferential transport of nitrogen to water-stressed offspring

    PubMed Central

    Roiloa, S. R.; Antelo, B.; Retuerto, R.

    2014-01-01

    Background and Aims One of the most striking attributes of clonal plants is their capacity for physiological integration, which enables movement of essential resources between connected ramets. This study investigated the capacity of physiological integration to buffer differences in resource availability experienced by ramets of the clonal wild strawberry plant, Fragaria vesca. Specifically, a study was made of the responses of connected and severed offspring ramets growing in environments with different water availability conditions (well watered or water stressed) and nitrogen forms (nitrate or ammonium). Methods The experimental design consisted of three factors, ‘integration’ (connected, severed) ‘water status’ (well watered, water stressed) and ‘nitrogen form’ (nitrate, ammonium), applied in a pot experiment. The effects of physiological integration were studied by analysing photochemical efficiency, leaf spectral reflectance, photosynthesis and carbon and nitrogen isotope discrimination, the last of which has been neglected in previous studies. Key Results Physiological integration buffered the stress caused by water deprivation. As a consequence, survival was improved in water-stressed offspring ramets that remained connected to their parent plants. The nitrogen isotope composition (δ15N) values in the connected water-stressed ramets were similar to those in ramets in the ammonium treatment; however, δ15N values in connected well-watered ramets were similar to those in the nitrate treatment. The results also demonstrated the benefit of integration for offspring ramets in terms of photochemical activity and photosynthesis. Conclusions This is the first study in which carbon and nitrogen isotopic discrimination has been used to detect physiological integration in clonal plants. The results for nitrogen isotope composition represent the first evidence of preferential transport of a specific form of nitrogen to compensate for stressful conditions

  8. Assessing environmental and physiological controls over water relations in a Scots pine (Pinus sylvestris L.) stand through analyses of stable isotope composition of water and organic matter.

    PubMed

    Brandes, Elke; Wenninger, Jochen; Koeniger, Paul; Schindler, Dirk; Rennenberg, Heinz; Leibundgut, Christian; Mayer, Helmut; Gessler, Arthur

    2007-01-01

    This study investigated the influence of meteorological, pedospheric and physiological factors on the water relations of Scots pine, as characterized by the origin of water taken up, by xylem transport as well as by carbon isotope discrimination (Delta13C) and oxygen isotope enrichment (Delta18O) of newly assimilated organic matter. For more than 1 year, we quantified delta2H and delta18O of potential water sources and xylem water as well as Delta13C and Delta18O in twig and trunk phloem organic matter biweekly, and related these values to continuously measured or modelled meteorological parameters, soil water content, stand transpiration (ST) and canopy stomatal conductance (G(s)). During the growing season, delta18O and delta2H of xylem water were generally in a range comparable to soil water from a depth of 2-20 cm. Long residence time of water in the tracheids uncoupled the isotopic signals of xylem and soil water in winter. Delta18O but not Delta13C in phloem organic matter was directly indicative of recent environmental conditions during the whole year. Delta18O could be described applying a model that included 18O fractionation associated with water exchange between leaf and atmosphere, and with the production of organic matter as well as the influence of transpiration. Phloem Delta13C was assumed to be concertedly influenced by G(s) and photosynthetically active radiation (PAR) (as a proxy for photosynthetic capacity). We conclude that isotope signatures can be used as effective tools (1) to characterize the seasonal dynamics in source and xylem water, and (2) to assess environmental effects on transpiration and G(s) of Scots pine, thus helping to understand and predict potential impacts of climate change on trees and forest ecosystems. PMID:17177880

  9. Growth and physiological responses of tree seedlings to experimental manipulation of light and water

    SciTech Connect

    Huston, M.A.; Holmgren, M.

    1995-06-01

    Seedlings of two tree species with similar tolerance to soil water and nutrient levels, but contrasting tolerance to shade (Acer saccharum and Liriodendron tulipifera) were grown in shade houses under 5 light levels (27%, 17%, 12%, 5%, and 1%) and three soil water regimes (5-9%, 11-15%, and >20%). Soil, light, and water conditions were representative of those in the Walker Branch Throughfall Displacement Experiment, where the same species are being monitored under field conditions. Treatments were maintained from mid-June through October, when all plants were harvested for determination of biomass allocation patterns. The only mortality occurred among the tulip poplars, but there was a significant interaction effect of the treatments on leaf area, total biomass, and allocation patterns. Highest growth rates in both species occurred at 17% light in the highest water treatment, with the 27% treatment showing reduced growth, perhaps due to photoinhibition. Gas exchange measurements indicated that the light compensation point increased under dry conditions.

  10. Water use efficiency and physiological response of rice cultivars under alternate wetting and drying conditions.

    PubMed

    Zhang, Yunbo; Tang, Qiyuan; Peng, Shaobing; Xing, Danying; Qin, Jianquan; Laza, Rebecca C; Punzalan, Bermenito R

    2012-01-01

    One of the technology options that can help farmers cope with water scarcity at the field level is alternate wetting and drying (AWD). Limited information is available on the varietal responses to nitrogen, AWD, and their interactions. Field experiments were conducted at the International Rice Research Institute (IRRI) farm in 2009 dry season (DS), 2009 wet season (WS), and 2010 DS to determine genotypic responses and water use efficiency of rice under two N rates and two water management treatments. Grain yield was not significantly different between AWD and continuous flooding (CF) across the three seasons. Interactive effects among variety, water management, and N rate were not significant. The high yield was attributed to the significantly higher grain weight, which in turn was due to slower grain filling and high leaf N at the later stage of grain filling of CF. AWD treatments accelerated the grain filling rate, shortened grain filling period, and enhanced whole plant senescence. Under normal dry-season conditions, such as 2010 DS, AWD reduced water input by 24.5% than CF; however, it decreased grain yield by 6.9% due to accelerated leaf senescence. The study indicates that proper water management greatly contributes to grain yield in the late stage of grain filling, and it is critical for safe AWD technology. PMID:23319883

  11. Physiology and pathophysiology of the vasopressin-regulated renal water reabsorption

    PubMed Central

    Boone, Michelle

    2008-01-01

    To prevent dehydration, terrestrial animals and humans have developed a sensitive and versatile system to maintain their water homeostasis. In states of hypernatremia or hypovolemia, the antidiuretic hormone vasopressin (AVP) is released from the pituitary and binds its type-2 receptor in renal principal cells. This triggers an intracellular cAMP signaling cascade, which phosphorylates aquaporin-2 (AQP2) and targets the channel to the apical plasma membrane. Driven by an osmotic gradient, pro-urinary water then passes the membrane through AQP2 and leaves the cell on the basolateral side via AQP3 and AQP4 water channels. When water homeostasis is restored, AVP levels decline, and AQP2 is internalized from the plasma membrane, leaving the plasma membrane watertight again. The action of AVP is counterbalanced by several hormones like prostaglandin E2, bradykinin, dopamine, endothelin-1, acetylcholine, epidermal growth factor, and purines. Moreover, AQP2 is strongly involved in the pathophysiology of disorders characterized by renal concentrating defects, as well as conditions associated with severe water retention. This review focuses on our recent increase in understanding of the molecular mechanisms underlying AVP-regulated renal water transport in both health and disease. PMID:18431594

  12. The physiological responses of Vallisneria natans to epiphytic algae with the increase of N and P concentrations in water bodies.

    PubMed

    Song, Yu-Zhi; Wang, Jin-Qi; Gao, Yong-Xia; Xie, Xue-Jian

    2015-06-01

    To reveal the mechanism of submerged plants decline in progressively eutrophicated freshwaters, physiological responses of Vallisneria natans to epiphytic algae were studied in simulation lab by measuring plant physiological indexes of chlorophyll content, malondialdehyde (MDA) content, and superoxide dismutase (SOD) activity based on a 2 × 4 factorial design with two epiphytic conditions (with epiphytic algae and without) and four levels of N and P concentrations in water (N-P[mg.L(-1)]: 0.5, 0.05; 2.5, 0.25; 4.5, 0.45; 12.5, 1.25). Compared with control (non-presence of epiphytic algae), chlorophyll contents of V. natans were significantly decreased (p < 0.01) for the presence of epiphytic algae under any concentrations of N and P in water bodies. While the presence of epiphytic algae induced peroxidation of membrane lipids, MDA contents of V. natans had significantly increased (p < 0.05) by comparing with control. SOD activity significantly enhanced (p < 0.05) with the presence of epiphytic algae in the treatments of T2 and T3 in the whole culture process by comparing with control, sometimes reaching an extremely significant level (p < 0.01). However, in the treatments of T1 and T4, SOD activity had no obvious change with the presence of epiphytic algae (p < 0.05) by comparing with control. At the end of the experiment, the effects of epiphytic algae on chlorophyll content and SOD activity in the leaves of V. natans were increased at first and then decreased with the concentrations of N and P in water, and MDA content became higher with the increase of N and P. concentrations. Repeated measurement data testing showed that the effects of epiphytic algae on the chlorophyll content and MDA content and SOD activity were significant, respectively (p < 0.001), the effects of epiphytic algae were combining with effects of concentrations of N and P (p < 0.001), respectively, and their interaction (p < 0.001). Our observations

  13. Azospirillum and arbuscular mycorrhizal colonization enhance rice growth and physiological traits under well-watered and drought conditions.

    PubMed

    Ruíz-Sánchez, Michel; Armada, Elisabet; Muñoz, Yaumara; García de Salamone, Inés E; Aroca, Ricardo; Ruíz-Lozano, Juan Manuel; Azcón, Rosario

    2011-07-01

    The response of rice plants to inoculation with an arbuscular mycorrhizal (AM) fungus, Azospirillum brasilense, or combination of both microorganisms, was assayed under well-watered or drought stress conditions. Water deficit treatment was imposed by reducing the amount of water added, but AM plants, with a significantly higher biomass, received the same amount of water as non-AM plants, with a poor biomass. Thus, the water stress treatment was more severe for AM plants than for non-AM plants. The results showed that AM colonization significantly enhanced rice growth under both water conditions, although the greatest rice development was reached in plants dually inoculated under well-watered conditions. Water level did not affect the efficiency of photosystem II, but both AM and A. brasilense inoculations increased this value. AM colonization increased stomatal conductance, particularly when associated with A. brasilense, which enhanced this parameter by 80% under drought conditions and by 35% under well-watered conditions as compared to single AM plants. Exposure of AM rice to drought stress decreased the high levels of glutathione that AM plants exhibited under well-watered conditions, while drought had no effect on the ascorbate content. The decrease of glutathione content in AM plants under drought stress conditions led to enhance lipid peroxidation. On the other hand, inoculation with the AM fungus itself increased ascorbate and proline as protective compounds to cope with the harmful effects of water limitation. Inoculation with A. brasilense also enhanced ascorbate accumulation, reaching a similar level as in AM plants. These results showed that, in spite of the fact that drought stress imposed by AM treatments was considerably more severe than non-AM treatments, rice plants benefited not only from the AM symbiosis but also from A. brasilense root colonization, regardless of the watering level. However, the beneficial effects of A. brasilense on most of the

  14. Effect of Salinity on Biomass Yield and Physiological and Stem-Root Anatomical Characteristics of Purslane (Portulaca oleracea L.) Accessions

    PubMed Central

    Juraimi, Abdul Shukor; Rafii, M. Y.; Abdul Hamid, Azizah

    2015-01-01

    13 selected purslane accessions were subjected to five salinity levels 0, 8, 16, 24, and 32 dS m−1. Salinity effect was evaluated on the basis of biomass yield reduction, physiological attributes, and stem-root anatomical changes. Aggravated salinity stress caused significant (P < 0.05) reduction in all measured parameters and the highest salinity showed more detrimental effect compared to control as well as lower salinity levels. The fresh and dry matter production was found to increase in Ac1, Ac9, and Ac13 from lower to higher salinity levels but others were badly affected. Considering salinity effect on purslane physiology, increase in chlorophyll content was seen in Ac2, Ac4, Ac6, and Ac8 at 16 dS m−1 salinity, whereas Ac4, Ac9, and Ac12 showed increased photosynthesis at the same salinity levels compared to control. Anatomically, stem cortical tissues of Ac5, Ac9, and Ac12 were unaffected at control and 8 dS m−1 salinity but root cortical tissues did not show any significant damage except a bit enlargement in Ac12 and Ac13. A dendrogram was constructed by UPGMA based on biomass yield and physiological traits where all 13 accessions were grouped into 5 clusters proving greater diversity among them. The 3-dimensional principal component analysis (PCA) has also confirmed the output of grouping from cluster analysis. Overall, salinity stressed among all 13 purslane accessions considering biomass production, physiological growth, and anatomical development Ac9 was the best salt-tolerant purslane accession and Ac13 was the most affected accession. PMID:25802833

  15. Physiology and proteomics of the water-deficit stress response in three contrasting peanut genotypes.

    PubMed

    Kottapalli, Kameswara Rao; Rakwal, Randeep; Shibato, Junko; Burow, Gloria; Tissue, David; Burke, John; Puppala, Naveen; Burow, Mark; Payton, Paxton

    2009-04-01

    Peanut genotypes from the US mini-core collection were analysed for changes in leaf proteins during reproductive stage growth under water-deficit stress. One- and two-dimensional gel electrophoresis (1- and 2-DGE) was performed on soluble protein extracts of selected tolerant and susceptible genotypes. A total of 102 protein bands/spots were analysed by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) and by quadrupole time-of-flight tandem mass spectrometry (Q-TOF MS/MS) analysis. Forty-nine non-redundant proteins were identified, implicating a variety of stress response mechanisms in peanut. Lipoxygenase and 1l-myo-inositol-1-phosphate synthase, which aid in inter- and intracellular stress signalling, were more abundant in tolerant genotypes under water-deficit stress. Acetyl-CoA carboxylase, a key enzyme of lipid biosynthesis, increased in relative abundance along with a corresponding increase in epicuticular wax content in the tolerant genotype, suggesting an additional mechanism for water conservation and stress tolerance. Additionally, there was a marked decrease in the abundance of several photosynthetic proteins in the tolerant genotype, along with a concomitant decrease in net photosynthesis in response to water-deficit stress. Differential regulation of leaf proteins involved in a variety of cellular functions (e.g. cell wall strengthening, signal transduction, energy metabolism, cellular detoxification and gene regulation) indicates that these molecules could affect the molecular mechanism of water-deficit stress tolerance in peanut. PMID:19143990

  16. Anatomical and physiological regulation of post-fire carbon and water exchange in canopies of two resprouting Eucalyptus species.

    PubMed

    Turnbull, Tarryn L; Buckley, Thomas N; Barlow, Alexandra M; Adams, Mark A

    2014-10-01

    The great majority of Eucalyptus spp. are facultative resprouters, and they dominate the eucalypt forests of Australia. Despite this numeric and geographic dominance, there is a general lack of knowledge of their capacity for carbon capture and water loss during canopy reinstation. After a crown-removing fire, we measured leaf-level determinants of carbon and water flux in resprouting canopies of Eucalyptus dives and E. radiata over the 3 years that followed. Leaf anatomy and physiology changed markedly during canopy reinstation, and leaves produced in the second year (2010) were distinct from those produced later. Leaves produced in 2010 were thicker (all measures of leaf anatomy), yet more porous (increased intercellular airspace), causing specific leaf area also to be greater. Indicators of heterotrophic activity, leaf respiration rate and light compensation point, were twofold greater in 2010, whereas all measures of photosynthetic capacity were greatest in leaves produced in 2011 and 2012. Whilst stomatal density, vein density and leaf hydraulic conductance all progressively decreased with time, neither leaf water status nor carbon isotope discrimination were affected. We conclude that canopy reinstation is primarily limited by pre-fire carbon stores, rather than by post-fire edaphic conditions (e.g., water availability), and thus argue that capacity for recovery is directly linked to pre-fire forest health. PMID:25108550

  17. Physiologically Based Pharmacokinetic modeling of the temperature-dependent dermal absorption of chloroform by humans following bath water exposures

    SciTech Connect

    Corley, Rick A. ); Gordon, Syd M.; Wallace, Lance A.

    2000-01-14

    The kinetics of chloroform in the exhaled breath of human volunteers exposed skin-only via bath water (concentrations < 100 ppb) were analyzed using a physiologically based pharmacokinetic (PBPK) model. Significant increases in exhaled chloroform (and thus bioavailability) were observed as exposure temperatures were increased from 30 to 40?C. The blood flows to the skin and effective skin permeability coefficients (Kp) were both varied to reflect the temperature-dependent changes in physiology and exhalation kinetics. At 40?C, no differences were observed between males and females. Therefore, Kp?s were determined ({approx}0.06 cm/hr) at a skin blood flow rate of 18% of the cardiac output. At 30 and 35?C, males exhaled more chloroform than females resulting in lower effective Kp?s calculated for females. At these lower temperatures, the blood flow to the skin was also reduced. Total amounts of chloroform absorbed averaged 41.9 and 43.6 mg for males and 11.5 and 39.9 mg for females exposed at 35 and 40?C, respectively. At 30?C, only 2/5 males and 1/5 females had detectable concentrations of chloroform in their exhaled breath. For perspective, the total intake of chloroform would have ranged from 79 - 194 mg if the volunteers had consumed 2 L of water orally at the concentrations used in this study. Thus, the relative contribution of dermal uptake of chloroform to the total body burdens associated with bathing for 30 min and drinking 2 L of water (ignoring contributions from inhalation exposures) was predicted to range from 1-28% depending on the temperature of the bath.

  18. Physiological ecology of desert iguana (Dipsosaurus dorsalis) eggs: temperature and water relations

    SciTech Connect

    Muth, A.

    1980-12-01

    The soil environment imposes constraints on the timing of oviposition and the location of suitable sites for egg burrows of the desert iguana (Dipsosaurus dorsalis). The effects of temperature and water potential on the developmental period and hatching success of eggs were determined. Eggs hatch normally between 28/sup 0/ and 38/sup 0/C at environmental water potentials between -50 and -1500 kPa. Predictions were derived for the timing and placement of egg clutches based on soil water potential and temperature profiles measured in the field and on the results of laboratory incubation experiments. The results suggest that egg burrows should be located at depths >22 cm in washes or possibly in sparsely vegetated areas away from creosote bushes. The biogeography of desert iguanas within the United States is discussed in relation to soil environments and tolerances of eggs. The physical factors affecting incubation may limit the geographical range of desert iguanas.

  19. A Physiological Stimulating Factor of Water Intake during and after Dry Forage Feeding in Large-type Goats

    PubMed Central

    Van Thang, Tran; Sunagawa, Katsunori; Nagamine, Itsuki; Kishi, Tetsuya; Ogura, Go

    2012-01-01

    plasma osmolality in the second hour of the 2 h feeding period is the main physiological stimulating factor of water intake during and after dry forage feeding in large-type goats. PMID:25049591

  20. Facing the River Gauntlet: Understanding the Effects of Fisheries Capture and Water Temperature on the Physiology of Coho Salmon

    PubMed Central

    Raby, Graham D.; Clark, Timothy D.; Farrell, Anthony P.; Patterson, David A.; Bett, Nolan N.; Wilson, Samantha M.; Willmore, William G.; Suski, Cory D.; Hinch, Scott G.; Cooke, Steven J.

    2015-01-01

    An improved understanding of bycatch mortality can be achieved by complementing field studies with laboratory experiments that use physiological assessments. This study examined the effects of water temperature and the duration of net entanglement on physiological disturbance and recovery in coho salmon (Oncorhynchus kisutch) after release from a simulated beach seine capture. Heart rate was monitored using implanted electrocardiogram biologgers that allowed fish to swim freely before and after release. A subset of fish was recovered in respirometers to monitor metabolic recovery, and separate groups of fish were sacrificed at different times to assess blood and white muscle biochemistry. One hour after release, fish had elevated lactate in muscle and blood plasma, depleted tissue energy stores, and altered osmoregulatory status, particularly in warmer (15 vs. 10°C) and longer (15 vs. 2 min) capture treatments. A significant effect of entanglement duration on blood and muscle metabolites remained after 4 h. Oxygen consumption rate recovered to baseline within 7–10 h. However, recovery of heart rate to routine levels was longer and more variable, with most fish taking over 10 h, and 33% of fish failing to recover within 24 h. There were no significant treatment effects on either oxygen consumption or heart rate recovery. Our results indicate that fishers should minimize handling time for bycatch and maximize oxygen supply during crowding, especially when temperatures are elevated. Physiological data, such as those presented here, can be used to understand mechanisms that underlie bycatch impairment and mortality, and thus inform best practices that ensure the welfare and conservation of affected species. PMID:25901952

  1. Physiology and proteomics of the water-deficit stress response in three contrasting peanut genotypes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Peanut (Arachis hypogaea L.) accessions from the US mini core collection were analyzed for differentially expressed leaf proteins during reproductive stage under water-deficit stress. Accessions showing tolerant and susceptible responses to stress were selected based on a bioassay involving chloroph...

  2. Impact of water and feed deprivation on physiological parameters in steers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A report in rats demonstrated that dehydration as the result of 8 d of water deprivation increased leakage of endotoxin from the intestine (Zurovsky and Barbiro, 2000 Experimental and toxicologic pathology 52:37-42). Given the large number of gram negative bacteria in the rumen of cattle, a much sho...

  3. Effect of benzyl butyl phthalate on physiology and proteome characterization of water celery (Ipomoea aquatica Forsk.).

    PubMed

    Chen, Wen-Ching; Huang, Han-Ching; Wang, Yei-Shung; Yen, Jui-Hung

    2011-07-01

    This study examined the effect of benzyl butyl phthalate (BBP), a phthalate ester (PAE) and an endocrine disruptor, on water celery, Ipomoea aquatica Forsk., one of the most popular leaf vegetables in Taiwan. After 28 days of cultivation, treatment with 100 mgL⁻¹ BBP retarded plant growth and decreased biomass and number of mature leaves and caused the accumulation of proline in leaves of water celery, but the concentrations of chlorophyll a and b in the leaves remained constant. 2-D gel electrophoresis and matrix-assisted laser desorption ionization time-of-flight mass spectrometry analysis of the proteome of leaf tissue revealed five protein spots with up- and down-regulated expression. The predicted protein XP_001417439 was down-regulated, which explained inhibition of plant growth, and the proteina XP_001417040, calreticulin, GAI-like protein 1, and (-)-linalool synthase were up-regulated, which indicates interference with the cell cycle and protein synthesis, as well as dwarfism of water celery. BBP is a stressor on the growth of water celery, and proteome analysis revealed the up- and down-regulation of genes involved in plant growth with BBP treatment. PMID:21496923

  4. Rating of Perceived Exertion and Physiological Responses in Water-Based Exercise

    PubMed Central

    Pinto, Stephanie Santana; Alberton, Cristine Lima; Zaffari, Paula; Cadore, Eduardo Lusa; Kanitz, Ana Carolina; Liedtke, Giane Veiga; Tartaruga, Marcus Peikriszwili; Kruel, Luiz Fernando Martins

    2015-01-01

    The aim of the present study was to relate the overall rating of perceived exertion (RPE-overall) with cardiorespiratory and neuromuscular variables during stationary running with the elbow flexion/extension performed with water-floating equipment. The sample consisted of eleven women that performed the water-based exercise at submaximal cadences. The heart rate, oxygen uptake, ventilation, and electromyographic signal (EMG) from biceps brachii (%EMG BB), triceps brachii (%EMG TB), biceps femoris (%EMG BF) and rectus femoris (%EMG RF) muscles were measured during the exercise, and the overall RPE was measured immediately following its completion. The Pearson product-moment linear correlation was used to investigate associations between the variables analyzed in the present study. Significant relationships were observed between the RPE-overall and all the cardiorespiratory variables, with the r values ranging from 0.60 to 0.70 (p<0.05). In addition, the RPE-overall showed a significant (p<0.05) relationship with %EMG BB (r=0.55) and %EMG BF (r=0.50). These results suggest an association between the RPE-overall with all cardiorespiratory and two neuromuscular variables during the execution of a water-based aerobic exercise using water-floating equipment. PMID:26839610

  5. Rating of Perceived Exertion and Physiological Responses in Water-Based Exercise.

    PubMed

    Pinto, Stephanie Santana; Alberton, Cristine Lima; Zaffari, Paula; Cadore, Eduardo Lusa; Kanitz, Ana Carolina; Liedtke, Giane Veiga; Tartaruga, Marcus Peikriszwili; Kruel, Luiz Fernando Martins

    2015-12-22

    The aim of the present study was to relate the overall rating of perceived exertion (RPE-overall) with cardiorespiratory and neuromuscular variables during stationary running with the elbow flexion/extension performed with water-floating equipment. The sample consisted of eleven women that performed the water-based exercise at submaximal cadences. The heart rate, oxygen uptake, ventilation, and electromyographic signal (EMG) from biceps brachii (%EMG BB), triceps brachii (%EMG TB), biceps femoris (%EMG BF) and rectus femoris (%EMG RF) muscles were measured during the exercise, and the overall RPE was measured immediately following its completion. The Pearson product-moment linear correlation was used to investigate associations between the variables analyzed in the present study. Significant relationships were observed between the RPE-overall and all the cardiorespiratory variables, with the r values ranging from 0.60 to 0.70 (p<0.05). In addition, the RPE-overall showed a significant (p<0.05) relationship with %EMG BB (r=0.55) and %EMG BF (r=0.50). These results suggest an association between the RPE-overall with all cardiorespiratory and two neuromuscular variables during the execution of a water-based aerobic exercise using water-floating equipment. PMID:26839610

  6. INSTABILITY OF THE WATER DISINFECTION BY-PRODUCT DIBROMOACETONITRILE UNDER PHYSIOLOGICAL CONDITIONS: KINETICS AND PRODUCT CHARACTERIZATION

    EPA Science Inventory

    Dibromoacetonitrile (DBAN) is a prevalent haloacetonitrile formed as a byproduct of water chlorination. DBAN is toxic in vivo and genotoxic in vitro and is a mouse skin tumor initiator. However, little is known about its mechanisms of toxicity or genotoxicity or its stability. Du...

  7. Relating water absorption features to soil moisture characteristics

    NASA Astrophysics Data System (ADS)

    Tian, Jia; Philpot, William D.

    2015-09-01

    The spectral reflectance of a sample of quartz sand was monitored as the sample progressed from air-dry to fully saturated, and then back to air-dry. Wetting was accomplished by spraying small amounts of water on the surface of the sample, and collecting spectra whenever change occurred. Drying was passive, driven by evaporation from the sand surface, with spectra collected every 5 minutes until the sample was air dry. Water content was determined by monitoring the weight of the sample through both wetting and drying. There was a pronounced difference in the pattern of change in reflectance during wetting and drying, with the differences being apparent both in spectral details (i.e., the depth of absorption bands) and in the magnitude of the reflectance for a particular water content. The differences are attributable to the disposition of water in the sample. During wetting, water initially occurred only on the surface, primarily as water adsorbed onto sand particles. With increased wetting the water infiltrated deeper into the sample, gradually covering all particles and filling the pore spaces. During drying, water and air were distributed throughout the sample for most of the drying period. The differences in water distribution are assumed to be the cause of the differences in reflectance and to the differences in the depths of four strong water absorption bands.

  8. Polyols in grape berry: transport and metabolic adjustments as a physiological strategy for water-deficit stress tolerance in grapevine.

    PubMed

    Conde, Artur; Regalado, Ana; Rodrigues, Diana; Costa, J Miguel; Blumwald, Eduardo; Chaves, M Manuela; Gerós, Hernâni

    2015-02-01

    Polyols are important metabolites that often function as carbon and energy sources and/or osmoprotective solutes in some plants. In grapevine, and in the grape berry in particular, the molecular aspects of polyol transport and metabolism and their physiological relevance are virtually unknown to date. Here, the biochemical function of a grapevine fruit mesocarp polyol transporter (VvPLT1) was characterized after its heterologous expression in yeast. This H(+)-dependent plasma membrane carrier transports mannitol (K m=5.4mM) and sorbitol (K m=9.5mM) over a broad range of polyols and monosaccharides. Water-deficit stress triggered an increase in the expression of VvPLT1 at the fully mature stage, allowing increased polyol uptake into pulp cells. Plant polyol dehydrogenases are oxireductases that reversibly oxidize polyols into monosaccharides. Mannitol catabolism in grape cells (K m=30.1mM mannitol) and mature berry mesocarps (K m=79mM) was, like sorbitol dehydrogenase activity, strongly inhibited (50-75%) by water-deficit stress. Simultaneously, fructose reduction into polyols via mannitol and sorbitol dehydrogenases was stimulated, contributing to their higher intracellular concentrations in water-deficit stress. Accordingly, the concentrations of mannitol, sorbitol, galactinol, myo-inositol, and dulcitol were significantly higher in berry mesocarps from water-deficit-stressed Tempranillo grapevines. Metabolomic profiling of the berry pulp by GC-TOF-MS also revealed many other changes in its composition induced by water deficit. The impact of polyols on grape berry composition and plant response to water deficit stress, via modifications in polyol transport and metabolism, was analysed by integrating metabolomics with transcriptional analysis and biochemical approaches. PMID:25433029

  9. Oxygen flux as an indicator of physiological stress in aquatic organisms: a real-time biomonitoring system of water quality

    NASA Astrophysics Data System (ADS)

    Sanchez, Brian C.; Yale, Gowri; Chatni, Rameez; Ochoa-Acuña, Hugo G.; Porterfield, D. Marshall; Mclamore, Eric S.; Sepúlveda, María S.

    2009-05-01

    The detection of harmful chemicals and biological agents in real time is a critical need for protecting water quality. We studied the real-time effects of five environmental contaminants with differing modes of action (atrazine, pentachlorophenol, cadmium chloride, malathion, and potassium cyanide) on respiratory oxygen consumption in 2-day post-fertilization fathead minnow (Pimephales promelas) eggs. Our objective was to assess the sensitivity of fathead minnow eggs using the self-referencing micro-optrode technique to detect instantaneous changes in oxygen consumption after brief exposures to low concentrations of contaminants. Oxygen consumption data indicated that the technique is indeed sensitive enough to reliably detect physiological alterations induced by all contaminants. After 2 h of exposure, we identified significant increases in oxygen consumption upon exposure to pentachlorophenol (100 and 1000 μg/L), cadmium chloride (0.0002 and 0.002 μg/L), and atrazine (150 μg/L). In contrast, we observed a significant decrease in oxygen flux after exposures to potassium cyanide (5.2, 22, and 44 μg/L) and atrazine (1500 μg/L). No effects were detected after exposures to malathion (200 and 340 μg/L). We have also tested the sensitivity of Daphnia magna embryos as another animal model for real-time environmental biomonitoring. Our results are so far encouraging and support further development of this technology as a physiologically coupled biomonitoring tool for the detection of environmental toxicants.

  10. Biological monitoring of toxic pollutants in ocean waters: physiological stress testing of bay and coastal mussels in California

    SciTech Connect

    Severeid, R.L.

    1983-01-01

    This report describes the results of the first two years of a study designed to assess the health of marine ecosystems; the Biological Effects Assessment Study. Using the mussel (Mytilus sp.) as a representative marine organism, the effects of exposure to chronic, low levels of toxic trace metals, pesticides and petroleum hydrocarbons were determined by a method of physiological stress testing, Scope for Growth. The Scope for Growth (SFG) index is the theoretical amount of energy available to an organism for growth and reproduction after maintenance requirements are taken into account. The more energy available, the higher the index, the healthier the organism. Low or negative values indicate the organism is stressed. Four commonly measured physiological parameters are used to calculate the SFG index: oxygen consumption, ammonia excretion, assimilation efficiency, and clearance rate. The report includes the results of the first two years of the Biological Effects Assessment Study, the background for State Water Resources Control Board's involvement in the field of pollution monitoring, a brief discussion of the methods, materials and calculations used to determine the SFG index, a discussion of the factors that influence the Scope for Growth index, and the future of the program.