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Sample records for situ nitrogen uptake

  1. Soil nitrogen availability and in situ nitrogen uptake by Acer rubrum L. and Pinus palustris Mill. in the southeastern U.S. Coastal Plain

    Science.gov (United States)

    Plant uptake of soil organic N in addition to inorganic N could play an important role in ecosystem N cycling as well as plant nutrition. We measured in situ plant uptake of organic and inorganic N by the dominant canopy species in two contrasting temperate forest ecosystems (bottomland floodplain ...

  2. In-situ Measured Carbon and Nitrogen Uptake Rates of Melt Pond Algae in the Western Arctic Ocean, 2014

    Science.gov (United States)

    Song, Ho Jung; Kim, Kwanwoo; Lee, Jae Hyung; Ahn, So Hyun; Joo, Houng-Min; Jeong, Jin Young; Yang, Eun Jin; Kang, Sung-Ho; Yun, Mi Sun; Lee, Sang Heon

    2018-03-01

    Although the areal coverage of melt pond in the Arctic Ocean has recently increased, very few biological researches have been conducted. The objectives in this study were to ascertain the uptake rates of carbon and nitrogen in various melt ponds and to understand the major controlling factors for the rates. We obtained 22 melt pond samples at ice camp 1 (146.17°W, 77.38°N) and 11 melt pond samples at ice camp 2 (169.79°W, 76.52°N). The major nutrient concentrations varied largely among melt ponds at the ice camps 1 and 2. The chl-a concentrations averaged from the melt ponds at camps 1 and 2 were 0.02-0.56 mg chl-a m-3 (0.12 ± 0.12 mg chl-a m-3) and 0.08-0.30 mg chl-a m-3 (0.16 ± 0.08 mg chl-a m-3), respectively. The hourly carbon uptake rates at camps 1 and 2 were 0.001-0.080 mg C m-3 h-1 (0.025 ± 0.024 mg C m-3 h-1) and 0.022-0.210 mg C m-3 h-1 (0.077 ± 0.006 mg C m-3 h-1), respectively. In comparison, the nitrogen uptake rates at camps 1 and 2 were 0.001-0.030 mg N m-3 h-1 (0.011 ± 0.010 mg N m-3 h-1) and 0.002-0.022 mg N m-3 h-1 (0.010 ± 0.006 mg N m-3 h-1), respectively. The values obtained in this study are significantly lower than those reported previously. A large portion of algal biomass trapped in the new forming surface ice in melt ponds appears to be one of the main potential reasons for the lower chl-a concentration and subsequently lower carbon and nitrogen uptake rates revealed in this study. A long-term monitoring program on melt ponds is needed to understand the response of the Arctic marine ecosystem to ongoing environmental changes.

  3. Uptake of fertilizer nitrogen and soil nitrogen by rice using 15N-labelled nitrogen fertilizer

    International Nuclear Information System (INIS)

    Reddy, K.R.; Patrick, W.H. Jr.

    1980-01-01

    Data from five field experiments using labelled nitrogen fertilizer were used to determine the relative effects of soil nitrogen and fertilizer nitrogen on rice yield. Yield of grain was closely correlated with total aboveground nitrogen uptake (soil + fertilizer), less closely correlated with soil nitrogen uptake and not significantly correlated with fertilizer nitrogen uptake. When yield increase rather than yield was correlated with fertilizer nitrogen uptake, the correlation coefficient was statistically significant. (orig.)

  4. Nitrogen uptake kinetics of freshly isolated zooxanthellae

    Digital Repository Service at National Institute of Oceanography (India)

    Wafar, M.V.M.; Wafar, S.; Rajkumar, R.

    that for nitrate [2.8 nmol. ( mu chl-a)./1h/1] and urea [0.37 nmol. ( mu chl-a)./1h/1]. Half-saturation constants for uptake of the three nitrogen compounds were in the range of 10-15 mu mol.l/1. Generally, uptake of any one nitrogen substrate appears to be inhibit...

  5. Uptake of organic nitrogen by plants

    Science.gov (United States)

    Torgny Nasholm; Knut Kielland; Ulrika. Ganeteg

    2009-01-01

    Languishing for many years in the shadow of plant inorganic nitrogen (N) nutrition research, studies of organic N uptake have attracted increased attention during the last decade. The capacity of plants to acquire organic N, demonstrated in laboratory and field settings, has thereby been well established. Even so, the ecological significance of organic N uptake for...

  6. Nitrogen uptake and assimilation by corn roots

    International Nuclear Information System (INIS)

    Yoneyama, Tadakatsu; Akiyama, Yoko; Kumazawa, Kikuo

    1977-01-01

    The site of nitrogen uptake in the apical root zone of corn was experimentally investigated. Two experiments were performed. The one is to see the assimilation of nitrate and ammonium and the effects of low temperature on it. The 4-day-old roots were treated with 15 N-labelled inorganic nitrogen of 20 ppm N in 5 x 10 -4 M CaSO 4 solution at 30 deg. C and 0 deg. C. The other is to see the nitrogen uptake at apical root zone and the utilization of newly absorbed nitrogen at the root top. The 4-day-old roots were transferred into 5 x 10 -4 M CaSO 4 solution containing 15 N-labelled ammonium nitrate of 40 ppm N. As a result, the effect of low temperature on the nitrogen uptake appeared to be more drastic in the case of nitrate than ammonium. The 15 N content of amino acids indicates that ammonium is assimilated into amino acids even at 0 deg. C, but nitrate is not. The ammonium nitrogen seemed to be absorbed at both cell dividing and elongating zones. On the other hand, nitrate nitrogen seemed to be strongly absorbed at cell elongating zone. The nitrogen in the apical part may be supplied not only by direct absorption but also by translocation from the basal part. The clear difference was found in the utilization of nitrate and ammonium nitrogen at the root top when the root was elongating. This may be due to the difference of assimilation products of inorganic nitrogen. Newly absorbed ammonium nitrogen is more utilizable for the growth of root top than nitrate nitrogen. (Iwakiri, K.)

  7. Replenishment and mobilization of intracellular nitrogen pools decouples wine yeast nitrogen uptake from growth

    OpenAIRE

    SANCHO FORNER, MARTA; Alicia Gutiérrez; BELTRAN CASELLAS, GEMMA; José Manuel Guillamon; Jonas Warringer

    2016-01-01

    Wine yeast capacity to take up nitrogen from the environment and catabolize it to support population growth, fermentation, and aroma production is critical to wine production. Under nitrogen restriction, yeast nitrogen uptake is believed to be intimately coupled to reproduction with nitrogen catabolite repression (NCR) suggested mediating this link. We provide a time- and strain-resolved view of nitrogen uptake, population growth, and NCR activity in wine yeasts. Nitrogen uptake was found to ...

  8. New nitrogen uptake strategy: specialized snow roots.

    Science.gov (United States)

    Onipchenko, Vladimir G; Makarov, Mikhail I; van Logtestijn, Richard S P; Ivanov, Viktor B; Akhmetzhanova, Assem A; Tekeev, Dzhamal K; Ermak, Anton A; Salpagarova, Fatima S; Kozhevnikova, Anna D; Cornelissen, Johannes H C

    2009-08-01

    The evolution of plants has yielded a wealth of adaptations for the acquisition of key mineral nutrients. These include the structure, physiology and positioning of root systems. We report the discovery of specialized snow roots as a plant strategy to cope with the very short season for nutrient uptake and growth in alpine snow-beds, i.e. patches in the landscape that remain snow-covered well into the summer. We provide anatomical, chemical and experimental (15)N isotope tracking evidence that the Caucasian snow-bed plant Corydalis conorhiza forms extensive networks of specialized above-ground roots, which grow against gravity to acquire nitrogen directly from within snow packs. Snow roots capture nitrogen that would otherwise partly run off down-slope over a frozen surface, thereby helping to nourish these alpine ecosystems. Climate warming is changing and will change mountain snow regimes, while large-scale anthropogenic N deposition has increased snow N contents. These global changes are likely to impact on the distribution, abundance and functional significance of snow roots.

  9. Nitrogen uptake into unfertilized pasture of the Willem Pretorius ...

    African Journals Online (AJOL)

    Nitrogen uptake into unfertilized pasture of the Willem Pretorius Game Reserve, ... The herbage yield of five main types of grassland in the Willem Pretorius Game Reserve was measured by clipping five 0, 5 m ... AJOL African Journals Online.

  10. Nitrogen uptake in the northeastern Arabian Sea during winter cooling

    Digital Repository Service at National Institute of Oceanography (India)

    Kumar, S.; Ramesh, R.; Dwivedi, R.M.; Raman, M.; Sheshshayee, M.S.; DeSouza, W.

    /plain; charset=UTF-8 Hindawi Publishing Corporation International Journal of Oceanography Volume 2010, Article ID 819029, 11 pages doi:10.1155/2010/819029 Research Article Nitrogen Uptake in the Northeastern Arabian Sea during Winter Cooling S. Kumar, 1...

  11. Effect of different biochars on Nitrogen uptake in poplar trees

    Science.gov (United States)

    George, Elizabeth; Tonon, Giustino; Scandellari, Francesca

    2014-05-01

    Influence of biochar on soil nitrogen transformation and plant uptake has been reported. This paper presents preliminary results of plant N uptake in poplars by using 15N isotope tracer approach Two types of biochar were applied to two sets of pots containing only sand and each pot received a pre-rooted poplar cutting. Half of the pots were inoculated with commercial mycorrhizal gel and the other half were left without. It is intended to provide information on how biochar, mycorrhiza and root interaction mediate nitrogen uptake and organ allocation.

  12. Nitrogen uptake and fertilizer nitrogen use efficiency of wheat under different soil water conditions

    International Nuclear Information System (INIS)

    Wang Baiqun; Zhang Wei; Yu Cunzu

    1999-01-01

    The pot experiment was conducted to study the effects of soil water regime and fertilizer nitrogen rate on the yields, nitrogen uptake and fertilizer nitrogen utilization of wheat by using 15 N tracer method. The results showed that the aboveground biomass, stem yield and grain yield increased with the increase of soil moisture in the fertilizer nitrogen treatments. All the yield increased with the increase of the fertilizer nitrogen rate in the soil water treatments. It was found that both soil water regime and fertilizer nitrogen rate significantly influenced the amount of nitrogen uptake by wheat according to the variance analysis. The amount of nitrogen uptake increased with the rise of the soil moisture in fertilizer nitrogen treatments and the amount also increased with the increase of the urea nitrogen rate in the soil water regime. Soil water regimes not only had an impact on nitrogen uptake but also had a close relationship with soil nitrogen supply and fertilizer nitrogen use efficiency. The soil A values decreased in urea treatment and increased with the rise of the soil moisture in the combination treatment of urea with pig manure. The fertilizer nitrogen use efficiency rose with the rise of the soil moisture in the same fertilizer nitrogen treatment. The fertilizer nitrogen use efficiency of the urea treatment was 13.3%, 27.9% and 32.3% in the soils with 50%, 70% and 90% of the field water capacity, respectively. The fertilizer nitrogen use efficiency in the combination treatment of urea with pig manure was 20.0%, 29.9% and 34.4% in the soils of above three levels, respectively. It was concluded that the low soil moisture restricted urea nitrogen use efficiency (UNUE) and the UNUE could be raised by combination treatment of urea with manure in the soil of enough moisture

  13. Nitrogen uptake and translocation by Chara

    NARCIS (Netherlands)

    Vermeer, C.P.; Escher, M.; Portielje, R.; Klein, de J.J.M.

    2003-01-01

    The potential for above-ground and below-ground uptake and subsequent internal translocation of ammonium (NH4+) and nitrate (NO3-) by the macroalga Chara spp. was investigated. In a two compartment experimental set-up separating above-ground and below-ground algal parts, the charophytes were exposed

  14. [Effects of water deficit and nitrogen fertilization on winter wheat growth and nitrogen uptake].

    Science.gov (United States)

    Qi, You-Ling; Zhang, Fu-Cang; Li, Kai-Feng

    2009-10-01

    Winter wheat plants were cultured in vitro tubes to study their growth and nitrogen uptake under effects of water deficit at different growth stages and nitrogen fertilization. Water deficit at any growth stages could obviously affect the plant height, leaf area, dry matter accumulation, and nitrogen uptake. Jointing stage was the most sensitive stage of winter wheat growth to water deficit, followed by flowering stage, grain-filling stage, and seedling stages. Rewatering after the water deficit at seedling stage had a significant compensation effect on winter wheat growth, and definite compensation effect was observed on the biomass accumulation and nitrogen absorption when rewatering was made after the water deficit at flowering stage. Under the same nitrogen fertilization levels, the nitrogen accumulation in root with water deficit at seedling, jointing, flowering, and grain-filling stages was reduced by 25.82%, 55.68%, 46.14%, and 16.34%, and the nitrogen accumulation in aboveground part was reduced by 33.37%, 51.71%, 27.01%, and 2.60%, respectively, compared with no water deficit. Under the same water deficit stages, the nitrogen content and accumulation of winter wheat decreased with decreasing nitrogen fertilization level, i. e., 0.3 g N x kg(-1) FM > 0.2 g N x kg(-1) FM > 0.1 g N x kg(-1) FM. Nitrogen fertilization had obvious regulation effect on winter wheat plant growth, dry matter accumulation, and nitrogen uptake under water stress.

  15. Nitrogen Cycling in the Mycorrhizosphere: Multipartite Interactions and Plant Nitrogen Uptake Vary with Fertilization Legacy

    Science.gov (United States)

    Hestrin, R.; Lehmann, J.

    2017-12-01

    Soil microbes play an important role in rhizosphere nutrient cycling and plant productivity. In this study, the contributions of soil microbes to organic matter mineralization and plant nitrogen uptake were investigated using incubation and microcosm experiments. Microbial inocula included arbuscular mycorrhizal fungi and microbial communities sampled across a long-term gradient of nitrogen fertilization. Stable isotopes, nanoSIMS imaging, and phospholipid fatty acid analysis were used to track carbon and nitrogen movement from organic matter into microbes, mycorrhizal fungi, and plants. Results show that multipartite relationships between plants and microbes increased plant growth and access to nitrogen from organic matter, and that nitrogen fertilization history had a lasting effect on microbial contributions to fungal and plant nitrogen uptake. This research links rhizosphere ecology and land management with terrestrial biogeochemistry.

  16. Cyclic variations in nitrogen uptake rate of soybean plants: ammonium as a nitrogen source

    Science.gov (United States)

    Henry, L. T.; Raper, C. D. Jr

    1989-01-01

    When NO3- is the sole nitrogen source in flowing solution culture, the net rate of nitrogen uptake by nonnodulated soybean (Glycine max L. Merr. cv Ransom) plants cycles between maxima and minima with a periodicity of oscillation that corresponds with the interval of leaf emergence. Since soybean plants accumulate similar quantities of nitrogen when either NH4+ or NO3- is the sole source in solution culture controlled at pH 6.0, an experiment was conducted to determine if the oscillations in net rate of nitrogen uptake also occur when NH4+ is the nitrogen source. During a 21-day period of vegetative development, net uptake of NH4+ was measured daily by ion chromatography as depletion of NH4+ from a replenished nutrient solution containing 1.0 millimolar NH4+. The net rate of NH4+ uptake oscillated with a periodicity that was similar to the interval of leaf emergence. Instances of negative net rates of uptake indicate that the transition between maxima and minima involved changes in influx and efflux components of net NH4+ uptake.

  17. Nitrite uptake by nitrogen-depleted wheat seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, W A; Johnson, R E; Volk, R J

    1974-01-01

    Intact, 14-day-old nitrogen-depleted wheat (Triticum vulgare cv. Blueboy) seedlings were exposed to solutions of 0.5 mM KNO/sub 2/, 0.05 mM CaSO/sub 4/ and 1 mM sodium 2-(N-morpholino)-ethanesulfonate, pH 6.1. Nitrite uptake was determined from depletion of the ambient solution or from incorporation of /sup 15/N in the tissue. An initial nitrite uptake shoulder was followed by a relatively slow uptake rate which subsequently increased to a substantially greater rate. This accelerated phase was maintained through 24 h. Nitrite accumulated to a slight extent in the root tissues during the first few hours but declined to low values when the accelerated rate was fully developed, indicating an increase in nitrite reductase activity paralleling the increase in nitrite uptake capacity. About 50% of the nitrogen absorbed as nitrite was translocated to the shoots by 9 to 12 h. Development of the accelerated nitrite uptake rate was restricted in excised roots, in intact plants kept in darkness, by 400 ..mu..g puromycin ml/sup -1/ and by 1 mM L-ethionine. When puromycin and L-ethionine were added after the accelerated phase had been initiated, their effects were not as detrimental as when they were added at first exposure to KNO/sub 2/. The two inhibitors restricted translocation more than uptake. The data indicate an involvement of protein synthesis and a requirement for movement of a substance from shoots to roots for maximal development of the accelerated nitrite uptake phase. A requirement for protein synthesis in the transport of soluble organic nitrogen from roots to shoots is also suggested.

  18. Uptake of exogenous spermidine by rat lungs perfused in situ

    International Nuclear Information System (INIS)

    Rannels, D.E.; Addison, J.L.

    1987-01-01

    Uptake of the polyamine spermidine (SPD) from the pulmonary circulation was characterized by using ventilated rat lungs perfused in situ with Krebs-Henseleit-bicarbonate buffer containing 4.5% bovine serum albumin, 5.6 mM glucose, and 20 amino acids at plasma levels. [ 14 C]SPD was accumulated by the lungs in a time- and concentration-dependent manner. The pathway of SPD uptake exhibited saturation kinetics with an apparent K/sub m/ in the range of 1 μM and a V/sub max/ of 450-540 pmol/g lung min. SPD uptake was inhibited by the naturally occurring polyamines putrescine and spermine (SPM) and by the inhibitor of polyamine synthesis, methyglyoxal bis(guanylhydrazone) (MGBG). Inhibition of SPD uptake by SPM followed competitive kinetics; although MGBG was also a competitive inhibitor of SPD uptake, MGBG was less effective than SPM. These observations indicate that SPD is taken up from the pulmonary circulation by a carrier-mediated pathway that is inhibited by other natural polyamines and by MGBG and exhibits by other natural polyamines and by MGBG and exhibits substrate affinity in the range of plasma SPD concentrations

  19. Uptake of exogenous spermidine by rat lungs perfused in situ

    Energy Technology Data Exchange (ETDEWEB)

    Rannels, D.E.; Addison, J.L.

    1987-01-01

    Uptake of the polyamine spermidine (SPD) from the pulmonary circulation was characterized by using ventilated rat lungs perfused in situ with Krebs-Henseleit-bicarbonate buffer containing 4.5% bovine serum albumin, 5.6 mM glucose, and 20 amino acids at plasma levels. (/sup 14/C)SPD was accumulated by the lungs in a time- and concentration-dependent manner. The pathway of SPD uptake exhibited saturation kinetics with an apparent K/sub m/ in the range of 1 ..mu..M and a V/sub max/ of 450-540 pmol/g lung min. SPD uptake was inhibited by the naturally occurring polyamines putrescine and spermine (SPM) and by the inhibitor of polyamine synthesis, methyglyoxal bis(guanylhydrazone) (MGBG). Inhibition of SPD uptake by SPM followed competitive kinetics; although MGBG was also a competitive inhibitor of SPD uptake, MGBG was less effective than SPM. These observations indicate that SPD is taken up from the pulmonary circulation by a carrier-mediated pathway that is inhibited by other natural polyamines and by MGBG and exhibits by other natural polyamines and by MGBG and exhibits substrate affinity in the range of plasma SPD concentrations.

  20. Effects of urban stream burial on nitrogen uptake and ...

    Science.gov (United States)

    Urbanization has resulted in extensive burial and channelization of headwater streams, yet little is known about impacts on stream ecosystem functions critical for reducing downstream nitrogen pollution. To characterize the biogeochemical impact of stream burial, we measured NO3- uptake, using 15N-NO3- isotope tracer releases, and whole stream metabolism, during four seasons in three paired buried and open streams reaches within the Baltimore Ecosystem Study Long-term Ecological Research Network. Stream burial increased NO3- uptake lengths, by a factor of 7.5 (p < 0.01) and decreased nitrate uptake velocity and areal nitrate uptake rate by factors of 8.2 (p = 0.01) and 9.6 (p < 0.001), respectively. Stream burial decreased gross primary productivity by a factor of 9.2 (p < 0.05) and decreased ecosystem respiration by a factor of 4.2 (p = 0.06). From statistical analysis of Excitation Emissions Matrices (EEMs), buried streams were also found to have significantly less labile dissolved organic matter. Furthermore, buried streams had significantly lower transient storage and water temperatures. Overall, differences in NO3- uptake and metabolism were primarily explained by decreased transient storage and light availability in buried streams. We estimate that stream burial increases daily watershed nitrate export by as much as 500% due to decreased in-stream retention and may considerably decrease carbon export via decreased primary production. These results

  1. Improved estimation of nitrogen uptake in grasslands using the nitrogen dilution curve

    Science.gov (United States)

    The critical nitrogen concentration (CNC) is a simple yet robust relationship that describes the changes in crop N during growth. We applied the concept of CNC to calculate N uptake across various cutting regimes. While it is well-established that decreasing cutting frequency changes growth rates, t...

  2. Molecular fundamentals of nitrogen uptake and transport in trees.

    Science.gov (United States)

    Castro-Rodríguez, Vanessa; Cañas, Rafael A; de la Torre, Fernando N; Pascual, Ma Belén; Avila, Concepción; Cánovas, Francisco M

    2017-05-01

    Nitrogen (N) is frequently a limiting factor for tree growth and development. Because N availability is extremely low in forest soils, trees have evolved mechanisms to acquire and transport this essential nutrient along with biotic interactions to guarantee its strict economy. Here we review recent advances in the molecular basis of tree N nutrition. The molecular characteristics, regulation, and biological significance of membrane proteins involved in the uptake and transport of N are addressed. The regulation of N uptake and transport in mycorrhized roots and transcriptome-wide studies of N nutrition are also outlined. Finally, several areas of future research are suggested. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  3. Nitrogen uptake efficiency of irrigated wheat in Egypt

    International Nuclear Information System (INIS)

    Abdel Monem, M.A.S.

    2000-01-01

    Egypt's current wheat production would be impossible without N fertilizers, the consumption of which has increased more than 75% in the last 20 years. The efficiency of uptake of applied N is low, and better management of both fertilizer and irrigation is needed to improve N recovery by crops and reduce losses from the plant/soil system. Field trials were conducted over a 3-year period, on Egypt's three main soil types: old irrigated land of the Nile valley, newly reclaimed sandy and calcareous soils, and salt-affected soil of the north delta. The responses of wheat cultivars to N, and patterns of N uptake and N loss, as affected by irrigation regime, were examined using 15 N. Cultivar Sakha 69 was more responsive to applied N and assimilated N more efficiently than other varieties under different soil types. Nitrogen loss from the sandy soil was as high as 57% whereas average loss in the clay soil was 17%. A higher water table in the salt-affected soil negatively affected N uptake. Irrigation with 75% of the required water for wheat had no effect on yield or N-uptake. (author)

  4. [Influence of water deficit and supplemental irrigation on nitrogen uptake by winter wheat and nitrogen residual in soil].

    Science.gov (United States)

    Wang, Zhaohui; Wang, Bing; Li, Shengxiu

    2004-08-01

    Pot experiment in greenhouse showed that water deficit at all growth stages and supplemental irrigation at tillering stage significantly decreased the nitrogen uptake by winter wheat and increased the mineral N residual (79.8-113.7 mg x kg(-1)) in soil. Supplemental irrigation at over-wintering, jointing or filling stage significantly increased the nitrogen uptake by plant and decreased the nitrogen residual (47.2-60.3 mg x kg(-1)) in soil. But, the increase of nitrogen uptake caused by supplemental irrigation did not always mean a high magnitude of efficient use of nitrogen by plants. Supplemental irrigation at over-wintering stage didn't induce any significant change in nitrogen content of grain, irrigation at filling stage increased the nitrogen content by 20.9%, and doing this at jointing stage decreased the nitrogen content by 19.6%, as compared to the control.

  5. Can Canopy Uptake Influence Nitrogen Acquisition and Allocation by Trees?

    Science.gov (United States)

    Nair, Richard; Perks, Mike; Mencuccini, Maurizio

    2015-04-01

    Nitrogen (N) fertilization due to atmospheric deposition of anthropogenic nitrogen (NDEP) may explain some of the net carbon (C) sink (0.6-0.7 Pg y-1) in temperate forests, but estimates of the additional C uptake due to atmospheric N additions (ΔCΔN) can vary by over an order of magnitude (~ 5 to 200 ΔCΔN). High estimates from several recent studies [e.g. Magnani (2007), Nature 447 848-850], deriving ΔCΔN from regional correlations between NDEP and measures of C uptake (such as eddy covariance -derived net ecosystem production, or forest inventory data) contradict estimates from other studies of 15N tracer applications added as fertilizer to the forest floor. A strong ΔCΔN effect requires nitrogen to be efficiently acquired by trees and allocated to high C:N, long-lived woody tissues, but these isotope experiments typically report relatively little (~ 20 %) of 15N added is found above-ground, with estimates are often attributed to co-variation with other factors across the range of sites investigated. However 15N-fertilization treatments often impose considerably higher total N loads than ambient NDEP and almost exclusively only apply mineral 15N treatments to the soil, often in a limited number of treatment events over relatively short periods of time. Excessive N deposition loads can induce negative physiological effects and limit the resulting ΔCΔN observed, and applying treatments to the soil may ignore the importance of canopy nitrogen uptake in overall forest nutrition. As canopies can directly take up nitrogen, the chronic, (relatively) low levels of ambient NDEP inputs from pollution may be acquired without some of the effects of heavy N loads, obtaining this N before it reaches the soil, and allowing canopies to substitute for, or supplement, edaphic N nutrition. The strength of this effect depends on how much N uptake can occur across the canopy under field conditions, and if this extra N supplies growth in woody tissues such as the stem, as

  6. Nitrogen deposition and prey nitrogen uptake control the nutrition of the carnivorous plant Drosera rotundifolia

    Energy Technology Data Exchange (ETDEWEB)

    Millett, J., E-mail: j.millett@lboro.ac.uk [Centre for Hydrological and Ecosystem Science, Department of Geography, Loughborough University, Loughborough LE11 3TU (United Kingdom); Foot, G.W. [Centre for Hydrological and Ecosystem Science, Department of Geography, Loughborough University, Loughborough LE11 3TU (United Kingdom); Svensson, B.M. [Department of Plant Ecology and Evolution, Uppsala University, Norbyvägen 18 D, SE-752 36 Uppsala (Sweden)

    2015-04-15

    Nitrogen (N) deposition has important negative impacts on natural and semi-natural ecosystems, impacting on biotic interactions across trophic levels. Low-nutrient systems are particularly sensitive to changes in N inputs and are therefore more vulnerable to N deposition. Carnivorous plants are often part of these ecosystems partly because of the additional nutrients obtained from prey. We studied the impact of N deposition on the nutrition of the carnivorous plant Drosera rotundifolia growing on 16 ombrotrophic bogs across Europe. We measured tissue N, phosphorus (P) and potassium (K) concentrations and prey and root N uptake using a natural abundance stable isotope approach. Our aim was to test the impact of N deposition on D. rotundifolia prey and root N uptake, and nutrient stoichiometry. D. rotundifolia root N uptake was strongly affected by N deposition, possibly resulting in reduced N limitation. The contribution of prey N to the N contained in D. rotundifolia ranged from 20 to 60%. N deposition reduced the maximum amount of N derived from prey, but this varied below this maximum. D. rotundifolia tissue N concentrations were a product of both root N availability and prey N uptake. Increased prey N uptake was correlated with increased tissue P concentrations indicating uptake of P from prey. N deposition therefore reduced the strength of a carnivorous plant–prey interaction, resulting in a reduction in nutrient transfer between trophic levels. We suggest that N deposition has a negative impact on D. rotundifolia and that responses to N deposition might be strongly site specific. - Highlights: • We measured nutrition of the carnivorous plant Drosera rotundifolia across Europe. • We measured tissue nutrient concentrations and prey and root N uptake at 16 sites. • Tissue N concentrations were a product of root N availability and prey N uptake. • N deposition reduced the maximum amount of N derived from prey. • N deposition reduced the strength of a

  7. Nitrogen deposition and prey nitrogen uptake control the nutrition of the carnivorous plant Drosera rotundifolia

    International Nuclear Information System (INIS)

    Millett, J.; Foot, G.W.; Svensson, B.M.

    2015-01-01

    Nitrogen (N) deposition has important negative impacts on natural and semi-natural ecosystems, impacting on biotic interactions across trophic levels. Low-nutrient systems are particularly sensitive to changes in N inputs and are therefore more vulnerable to N deposition. Carnivorous plants are often part of these ecosystems partly because of the additional nutrients obtained from prey. We studied the impact of N deposition on the nutrition of the carnivorous plant Drosera rotundifolia growing on 16 ombrotrophic bogs across Europe. We measured tissue N, phosphorus (P) and potassium (K) concentrations and prey and root N uptake using a natural abundance stable isotope approach. Our aim was to test the impact of N deposition on D. rotundifolia prey and root N uptake, and nutrient stoichiometry. D. rotundifolia root N uptake was strongly affected by N deposition, possibly resulting in reduced N limitation. The contribution of prey N to the N contained in D. rotundifolia ranged from 20 to 60%. N deposition reduced the maximum amount of N derived from prey, but this varied below this maximum. D. rotundifolia tissue N concentrations were a product of both root N availability and prey N uptake. Increased prey N uptake was correlated with increased tissue P concentrations indicating uptake of P from prey. N deposition therefore reduced the strength of a carnivorous plant–prey interaction, resulting in a reduction in nutrient transfer between trophic levels. We suggest that N deposition has a negative impact on D. rotundifolia and that responses to N deposition might be strongly site specific. - Highlights: • We measured nutrition of the carnivorous plant Drosera rotundifolia across Europe. • We measured tissue nutrient concentrations and prey and root N uptake at 16 sites. • Tissue N concentrations were a product of root N availability and prey N uptake. • N deposition reduced the maximum amount of N derived from prey. • N deposition reduced the strength of a

  8. Nitrogen uptake dynamics, yield and quality as influenced by nitrogen fertilization in Piel de sapo melon

    Energy Technology Data Exchange (ETDEWEB)

    Castellanos, M. T.; Cabello, M. J.; Cartagena, M. C.; Tarquis, A. M.; Arce, A.; Ribas, F.

    2012-11-01

    The need to reduce nitrogen (N) fertilizer pollution strengthens the importance of improving the utilization efficiency of applied N to crops. This requires knowledge of crop N uptake characteristics and how fertilization management affects it. A three-year field experiment was conducted from May to September in central Spain to investigate the influence of different N rates, which ranged from 11 to 393 kg ha{sup -}1, applied through drip irrigation, on the dynamics of N uptake, nitrogen use efficiency (NUE), fruit yield and quality of a Piel de sapo melon crop (Cucumis melo L. cv. Sancho). Both N concentration and N content increased in different plant parts with the N rate. Leaves had the highest N concentration, which declined by 40-50% from 34-41 days after transplanting (DAT), while the highest N uptake rate was observed from 30-35 to 70-80 DAT, coinciding with fruit development. In each year, NUE declined with increasing N rate. With N fertilizer applications close to the optimum N rate of 90-100 kg ha -1, the fruits removed approximately 60 kg N ha -1, and the amount of N in the crop residue was about 80 kg N ha -1; this serves to replenish the organic nutrient pool in the soil and may be used by subsequent crops following mineralization. (Author) 36 refs.

  9. Symbiotic nitrogen fixation and nitrate uptake by the pea crop

    International Nuclear Information System (INIS)

    Jensen, E.S.

    1986-08-01

    Symbiotic nitrogen fixation and nitrate uptake by pea plants (Pisum sativum L.) were studied in field and pot experiments using the 15 N isotope dilution technique and spring barley as a non-fixing reference crop. Barley, although not ideal, seemed to be a suitable reference for pea in the 15 N-technique. Maximum N 2 fixation activity of 10 kg N fixed per ha per day was reached around the flat pod growth stage, and the activity decreased rapidly during pod-filling. The pea crop fixed between 100 and 250 kg N ha -1 , corresponding to from 45 to 80 per cent of total crop N. The amount of symbiotically fixed N 2 depended on the climatic conditions in the experimental year, the level of soil mineral N and the pea cultivar. Field-grown pea took up 60 to 70 per cent of the N-fertilizer supplied. The supply of 50 kg NO 3 -N ha -1 inhibited the N 2 fixation approximately 15 per cent. Small amounts of fertilizer N, supplied at sowing (starter-N), slightly stimulated the vegetative growth of pea, but the yields of seed dry matter and protein were not significantly influenced. In the present field experiments the environmental conditions, especially the distribution of rainfall during the growth season, seemed to be more important in determining the protein and dry matter yield of the dry pea crop, than the ability of pea to fix nitrogen symbiotically. However, fertilizer N supplied to pot-grown pea plants at the flat pod growth stage or as split applications significantly increased the yield of seed dry matter and protein. (author)

  10. [Effects of simulated nitrogen deposition on weeds growth and nitrogen uptake].

    Science.gov (United States)

    Jiang, Qiqing; Tang, Jianjun; Chen, Xin; Chen, Jing; Yang, Ruyi; Hu, S

    2005-05-01

    In this paper, a greenhouse experiment was conducted to study the responses of different functional groups weeds to simulated nitrogen deposition (4.0 g N.m(-2).yr(-1)). Native weed species Poa annua, Lolium perenne, Avena fatua, Medicago lupulina, Trifolium repens, Plantago virginica, Veronica didyma, Echinochloa crusgalli var. mitis, Eleusine indica and Amaranthus spinosus in orchard ecosystem were used test materials, and their above-and underground biomass and nitrogen uptake were measured. The results showed that under simulated N deposition, the total biomass, shoot biomass and root biomass of all weed species tended increase, while the total biomass was differed for different functional groups of weeds. The biomass of C4 grass, legumes and C3 grass was significantly increased under N deposition, while that of C3 and C4 forbs was not significantly impacted. The root/shoot biomass ratio of Avena fatua and Plantago virginica was enhanced by N deposition, but that of Poa annu, Lolium perenne, Medicago lupulina, Trifolium repens and Amarathus spinosus was not impacted significantly. N deposition had no significant effect on plant N concentration, but significantly enhanced the N uptake of all test weed species except Amarathus spinosus, Poa annua and Veronica didyma. was suggested that the further increase of N deposition might speed up the changes of the community structure weed species due to their different responses to N deposition.

  11. A mechanistic, globally-applicable model of plant nitrogen uptake, retranslocation and fixation

    Science.gov (United States)

    Fisher, J. B.; Tan, S.; Malhi, Y.; Fisher, R. A.; Sitch, S.; Huntingford, C.

    2008-12-01

    Nitrogen is one of the nutrients that can most limit plant growth, and nitrogen availability may be a controlling factor on biosphere responses to climate change. We developed a plant nitrogen assimilation model based on a) advective transport through the transpiration stream, b) retranslocation whereby carbon is expended to resorb nitrogen from leaves, c) active uptake whereby carbon is expended to acquire soil nitrogen, and d) biological nitrogen fixation whereby carbon is expended for symbiotic nitrogen fixers. The model relies on 9 inputs: 1) net primary productivity (NPP), 2) plant C:N ratio, 3) available soil nitrogen, 4) root biomass, 5) transpiration rate, 6) saturated soil depth,7) leaf nitrogen before senescence, 8) soil temperature, and 9) ability to fix nitrogen. A carbon cost of retranslocation is estimated based on leaf nitrogen and compared to an active uptake carbon cost based on root biomass and available soil nitrogen; for nitrogen fixers both costs are compared to a carbon cost of fixation dependent on soil temperature. The NPP is then allocated to optimize growth while maintaining the C:N ratio. The model outputs are total plant nitrogen uptake, remaining NPP available for growth, carbon respired to the soil and updated available soil nitrogen content. We test and validate the model (called FUN: Fixation and Uptake of Nitrogen) against data from the UK, Germany and Peru, and run the model under simplified scenarios of primary succession and climate change. FUN is suitable for incorporation into a land surface scheme of a General Circulation Model and will be coupled with a soil model and dynamic global vegetation model as part of a land surface model (JULES).

  12. Nitrogen removal from landfill leachate via ex situ nitrification and sequential in situ denitrification

    International Nuclear Information System (INIS)

    Zhong Qi; Li Daping; Tao Yong; Wang Xiaomei; He Xiaohong; Zhang Jie; Zhang Jinlian; Guo Weiqiang; Wang Lan

    2009-01-01

    Ex situ nitrification and sequential in situ denitrification represents a novel approach to nitrogen management at landfills. Simultaneous ammonia and organics removal was achieved in a continuous stirred tank reactor (CSTR). The results showed that the maximum nitrogen loading rate (NLR) and the maximum organic loading rate (OLR) was 0.65 g N l -1 d -1 and 3.84 g COD l -1 d -1 , respectively. The ammonia and chemical oxygen demand (COD) removal was over 99% and 57%, respectively. In the run of the CSTR, free ammonia (FA) inhibition and low dissolved oxygen (DO) were found to be key factors affecting nitrite accumulation. In situ denitrification was studied in a municipal solid waste (MSW) column by recalculating nitrified leachate from CSTR. The decomposition of MSW was accelerated by the recirculation of nitrified leachate. Complete reduction of total oxidized nitrogen (TON) was obtained with maximum TON loading of 28.6 g N t -1 TS d -1 and denitrification was the main reaction responsible. Additionally, methanogenesis inhibition was observed while TON loading was over 11.4 g N t -1 TS d -1 and the inhibition was enhanced with the increase of TON loading

  13. Relationship of Nitrogen Use Efficiency with the Activities of Enzymes Involved in Nitrogen Uptake and Assimilation of Finger Millet Genotypes Grown under Different Nitrogen Inputs

    Directory of Open Access Journals (Sweden)

    Nidhi Gupta

    2012-01-01

    Full Text Available Nitrogen responsiveness of three-finger millet genotypes (differing in their seed coat colour PRM-1 (brown, PRM-701 (golden, and PRM-801 (white grown under different nitrogen doses was determined by analyzing the growth, yield parameters and activities of nitrate reductase (NR, glutamine synthetase (GS, glutamate synthase; GOGAT, and glutamate dehydrogenase (GDH at different developmental stages. High nitrogen use efficiency and nitrogen utilization efficiency were observed in PRM-1 genotype, whereas high nitrogen uptake efficiency was observed in PRM-801 genotype. At grain filling nitrogen uptake efficiency in PRM-1 negatively correlated with NR, GS, GOGAT activities whereas it was positively correlated in PRM-701 and PRM-801, however, GDH showed a negative correlation. Growth and yield parameters indicated that PRM-1 responds well at high nitrogen conditions while PRM-701 and PRM-801 respond well at normal and low nitrogen conditions respectively. The study indicates that PRM-1 is high nitrogen responsive and has high nitrogen use efficiency, whereas golden PRM-701 and white PRM-801 are low nitrogen responsive genotypes and have low nitrogen use efficiency. However, the crude grain protein content was higher in PRM-801 genotype followed by PRM-701 and PRM-1, indicating negative correlation of nitrogen use efficiency with source to sink relationship in terms of seed protein content.

  14. Simulating Root Density Dynamics and Nitrogen Uptake – Can a Simple Approach be Sufficient?

    OpenAIRE

    Pedersen, Anders; Zhang, Kefeng; Jensen, Lars Stoumann; Thorup-Kristensen, Kristian

    2007-01-01

    The modeling of root growth in many plant–soil models is simple and with few possibilities to adapt simulated root proliferation and depth distribution to that actually found with different crop species. Here we propose a root model, developed to describe root growth, root density and nitrogen uptake. The model focuses on annual crops, and attempts to model root growth of different crop species and row crops and its significance for nitrogen uptake from different parts of the soil volume.

  15. Nitrogen uptake and regeneration in a frontal region of the Algerian current (western Mediterranean Sea): new evaluation of new production

    International Nuclear Information System (INIS)

    Gentilhomme, V.; Raimbault, P.

    1994-01-01

    The uptake and regeneration of four forms of nitrogen (NO 3 - , NO 2 - , NH 4 + and urea) have been studied, in the euphotic layer of a frontal area (Algerian current), in relation with hydrological, chemical and biological parameters. In this area vertical stratification is pronounced; a deep chlorophyll maximum at the bottom of the euphotic layer is present. Results show the importance of measuring urea uptake and regeneration in the study of nitrogen cycling, because this component can be regenerated as rapidly as ammonia, and is a source of nitrogen for phytoplankton. Other results show the oxidation of ammonia to nitrate in the euphotic layer, and particularly at the base of this layer. This nitrification is a source or in situ regenerated nitrate, and could lead to a wrong estimation of the new production estimation. In the deep chlorophyll maximum, there is a maximum of nitrogen primary production but not a maximum of new production. In fact, regenerated production is the most important process over the whole euphotic layer of the Algerian basin. (authors). 56 refs., 2 figs., 2 tabs

  16. The effect of the rate and method of nitrogen application on nitrogen uptake and utilization by broccoli (Brassica oleracea var. italica)

    NARCIS (Netherlands)

    Everaarts, A.P.; Willigen, de P.

    1999-01-01

    The effect of the rate and method of nitrogen application on nitrogen uptake and utilization by broccoli (Brassica oleracea var. italica) was studied in four field experiments. The methods of application were broadcast application vs band placement and split application. Maximum uptake of nitrogen

  17. Carbon availability for the fungus triggers nitrogen uptake and transport in the arbuscular mycorrhizal symbiosis

    Science.gov (United States)

    The arbuscular mycorrhizal (AM) symbiosis is characterized by a transfer of nutrients in exchange for carbon. We tested the effect of the carbon availability for the AM fungus Glomus intraradices on nitrogen (N) uptake and transport in the symbiosis. We followed the uptake and transport of 15N and ...

  18. Azospirillum Inoculation Alters Nitrate Reductase Activity and Nitrogen Uptake in Wheat Plant Under Water Deficit Conditions

    OpenAIRE

    N. Aliasgharzad, N. Aliasgharzad; Heydaryan, Zahra; Sarikhani, M.R

    2014-01-01

    Water deficit stress usually diminishes nitrogen uptake by plants. There are evidences that some nitrogen fixing bacteria can alleviate this stress by supplying nitrogen and improving its metabolism in plants. Four Azospirillum strains, A. lipoferum AC45-II, A. brasilense AC46-I, A. irakense AC49-VII and A. irakense AC51-VI were tested for nitrate reductase activity (NRA). In a pot culture experiment using a sandy loam soil, wheat plants (Triticum aestivum L. cv. Sardari) were inoculated with...

  19. Plant traits related to nitrogen uptake influence plant-microbe competition.

    Science.gov (United States)

    Moreau, Delphine; Pivato, Barbara; Bru, David; Busset, Hugues; Deau, Florence; Faivre, Céline; Matejicek, Annick; Strbik, Florence; Philippot, Laurent; Mougel, Christophe

    2015-08-01

    Plant species are important drivers of soil microbial communities. However, how plant functional traits are shaping these communities has received less attention though linking plant and microbial traits is crucial for better understanding plant-microbe interactions. Our objective was to determine how plant-microbe interactions were affected by plant traits. Specifically we analyzed how interactions between plant species and microbes involved in nitrogen cycling were affected by plant traits related to 'nitrogen nutrition in interaction with soil nitrogen availability. Eleven plant species, selected along an oligotrophic-nitrophilic gradient, were grown individually in a nitrogen-poor soil with two levels of nitrate availability. Plant traits for both carbon and nitrogen nutrition were measured and the genetic structure and abundance of rhizosphere. microbial communities, in particular the ammonia oxidizer and nitrate reducer guilds, were analyzed. The structure of the bacterial community in the rhizosphere differed significantly between plant species and these differences depended on nitrogen availability. The results suggest that the rate of nitrogen uptake per unit of root biomass and per day is a key plant trait, explaining why the effect of nitrogen availability on the structure of the bacterial community depends on the plant species. We also showed that the abundance of nitrate reducing bacteria always decreased with increasing nitrogen uptake per unit of root biomass per day, indicating that there was competition for nitrate between plants and nitrate reducing bacteria. This study demonstrates that nitrate-reducing microorganisms may be adversely affected by plants with a high nitrogen uptake rate. Our work puts forward the role of traits related to nitrogen in plant-microbe interactions, whereas carbon is commonly considered as the main driver. It also suggests that plant traits related to ecophysiological processes, such as nitrogen uptake rates, are more

  20. Nitrogen removal in maturation waste stabilisation ponds via biological uptake and sedimentation of dead biomass.

    Science.gov (United States)

    Camargo Valero, M A; Mara, D D; Newton, R J

    2010-01-01

    In this work a set of experiments was undertaken in a pilot-scale WSP system to determine the importance of organic nitrogen sedimentation on ammonium and total nitrogen removals in maturation ponds and its seasonal variation under British weather conditions, from September 2004 to May 2007. The nitrogen content in collected sediment samples varied from 4.17% to 6.78% (dry weight) and calculated nitrogen sedimentation rates ranged from 273 to 2868 g N/ha d. High ammonium removals were observed together with high concentrations of chlorophyll-a in the pond effluent. Moreover, chlorophyll-a had a very good correlation with the corresponding increment of VSS (algal biomass) and suspended organic nitrogen (biological nitrogen uptake) in the maturation pond effluents. Therefore, when ammonium removal reached its maximum, total nitrogen removal was very poor as most of the ammonia taken up by algae was washed out in the pond effluent in the form of suspended solids. After sedimentation of the dead algal biomass, it was clear that algal-cell nitrogen was recycled from the sludge layer into the pond water column. Recycled nitrogen can either be taken up by algae or washed out in the pond effluent. Biological (mainly algal) uptake of inorganic nitrogen species and further sedimentation of dead biomass (together with its subsequent mineralization) is one of the major mechanisms controlling in-pond nitrogen recycling in maturation WSP, particularly when environmental and operational conditions are favourable for algal growth.

  1. Evaluation of nitrogen uptake patterns in spring and winter wheat in western Oregon

    International Nuclear Information System (INIS)

    Baloch, D.M.; Malghani, M.A.K.; Khan, M.A.; Kakar, E.

    2010-01-01

    An understanding of the ground nitrogen (N) uptake pattern for wheat (Triticum aestivum L.) is essential to facilitate nitrogen management. The purpose of this study was to determine the nitrogen uptake pattern of spring and winter wheat grown in western Oregon, USA. Data used in this study were obtained from three different trials. For spring wheat rotation trials five spring wheat cultivars were used. Fertilizer N (16-16-16-4) at the rate of 140 kg ha/sup -1/ was applied at the time of planting. In small plot rotation trials five fertilizer treatments - 0, 50, 100,150 and 200 kg N ha/sup -1/ were used. Rotations include winter wheat following clover and winter wheat following oat. The N uptake and dry matter yield of winter wheat were also determined from unfertilized plots of wheat trial. The maximum N uptake for spring wheat and winter wheat were at 1100 and 2000 accumulated growing degree days (GDD), before Feekes 10, respectively. The maximum N uptake rate for spring wheat, 0.038 kg N GDD/sup -1/, occurred at 750 GDD and the peak N uptake was observed approximately 35 days after Feekes 2. Nitrogen uptake in winter wheat was significantly affected by rotations. (author)

  2. Improving representation of nitrogen uptake, allocation, and carbon assimilation in the Community Land Model

    Science.gov (United States)

    Ghimire, B.; Riley, W. J.; Koven, C.

    2013-12-01

    Nitrogen is the most important nutrient limiting plant carbon assimilation and growth, and is required for production of photosynthetic enzymes, growth and maintenance respiration, and maintaining cell structure. The forecasted rise in plant available nitrogen through atmospheric nitrogen deposition and the release of locked soil nitrogen by permafrost thaw in high latitude ecosystems is likely to result in an increase in plant productivity. However a mechanistic representation of plant nitrogen dynamics is lacking in earth system models. Most earth system models ignore the dynamic nature of plant nutrient uptake and allocation, and further lack tight coupling of below- and above-ground processes. In these models, the increase in nitrogen uptake does not translate to a corresponding increase in photosynthesis parameters, such as maximum Rubisco capacity and electron transfer rate. We present an improved modeling framework implemented in the Community Land Model version 4.5 (CLM4.5) for dynamic plant nutrient uptake, and allocation to different plant parts, including leaf enzymes. This modeling framework relies on imposing a more realistic flexible carbon to nitrogen stoichiometric ratio for different plant parts. The model mechanistically responds to plant nitrogen uptake and leaf allocation though changes in photosynthesis parameters. We produce global simulations, and examine the impacts of the improved nitrogen cycling. The improved model is evaluated against multiple observations including TRY database of global plant traits, nitrogen fertilization observations and 15N tracer studies. Global simulations with this new version of CLM4.5 showed better agreement with the observations than the default CLM4.5-CN model, and captured the underlying mechanisms associated with plant nitrogen cycle.

  3. Traits affecting early season nitrogen uptake in nine legume species

    Directory of Open Access Journals (Sweden)

    Elana Dayoub

    2017-02-01

    Full Text Available Legume crops are known to have low soil N uptake early in their life cycle, which can weaken their ability to compete with other species, such as weeds or other crops in intercropping systems. However, there is limited knowledge on the main traits involved in soil N uptake during early growth and for a range of species. The objective of this research was to identify the main traits explaining the variability among legume species in soil N uptake and to study the effect of the soil mineral N supply on the legume strategy for the use of available N sources during early growth. Nine legume species were grown in rhizotrons with or without N supply. Root expansion, shoot and root biomass, nodule establishment, N2 fixation and mineral soil N uptake were measured. A large interspecific variability was observed for all traits affecting soil N uptake. Root lateral expansion and early biomass in relation to seed mass were the major traits influencing soil N uptake regardless of the level of soil N availability. Fenugreek, lentil, alfalfa, and common vetch could be considered weak competitors for soil N due to their low plant biomass and low lateral root expansion. Conversely, peanut, pea, chickpea and soybean had a greater soil N uptake. Faba bean was separated from other species having a higher nodule biomass, a higher N2 fixation and a lower seed reserve depletion. Faba bean was able to simultaneously fix N2 and take up soil N. This work has identified traits of seed mass, shoot and root biomass, root lateral expansion, N2 fixation and seed reserve depletion that allowing classification of legume species regarding their soil N uptake ability during early growth.

  4. Nitrogenous fertilizer uptake by guinea grass in several growth flushes

    International Nuclear Information System (INIS)

    Ambrosano, E.J.; Ambrosano, G.M.B.

    1996-01-01

    Nitrogen recovery was evaluated by the 15 N absorption by guineagrass cv. Tobiata. 15 N fertilizer was applied in February, March, May, June, August and September, in posts containing 5 kg of limed and fertilized soil, under greenhouse conditions in Piracicaba, State of Sao Paulo, Brazil. For each 15 N application three cuttings were performed at approximately 5-7 week interval. The following measurements were taken: consumed water, dry matter yield, nitrogen content, nitrogen in the plant derived form the fertilizers (Ndff), nitrogen recovery (R), and the relation between dry matter yield and nitrogen content. It was also determined the number of vegetative and reproductive tillers and apical meristem elimination. Plant growth was reduced after flowing; highest values of nitrogen recovery in the three cutting were observed for 15 N-fertilizer applied in September and August; highest residual effects, in the second and third cuttings after fertilizers 15 N applications, were observed in September, June and August, reaching 22% in September. (author)

  5. Seasonal changes in nitrogen availability, and root and microbial uptake of 15N13C9-phenylalanine and 15N-ammonium in situ at a temperate heath

    DEFF Research Database (Denmark)

    Andresen, Louise C.; Michelsen, Anders; Jonasson, Sven Evert

    2011-01-01

    In the plant biosynthesis of secondary compounds, phenylalanine is a precursor of condensed tannins. Tannins are deposited into the soil in plant root exudates and dead plant material and have been suggested to precipitate some soil nutrients and hence reduce nutrient availability for plants. Free...... amino acid,inorganic and microbial N concentration during the growing season was investigated in an ecosystem with a natural tannin chemosphere. The influence of tannins on the uptake of nitrogen in plants and microbes was followed by injecting tannic acid (TA), ammonium-15N and phenylalanine-15N/13C9...

  6. Nitrogen Uptake in Soils under Different Water Table Depths ...

    African Journals Online (AJOL)

    A mathematical model was used to examine the interactions of NH4 + transport to rice roots, as well as to calculate root length densities required to relate N uptake to concentrations of NH4 + in solution around the rooting medium for three water treatments: water table 30 cm below the surface, 15 cm below the surface and ...

  7. Nitrogen uptake and regeneration pathways in the equatorial Pacific: a basin scale modeling study

    Directory of Open Access Journals (Sweden)

    R. Le Borgne

    2009-11-01

    Full Text Available It is well known that most primary production is fueled by regenerated nitrogen in the open ocean. Therefore, studying the nitrogen cycle by focusing on uptake and regeneration pathways would advance our understanding of nitrogen dynamics in the marine ecosystem. Here, we carry out a basin-scale modeling study, by assessing model simulations of nitrate and ammonium, and rates of nitrate uptake, ammonium uptake and regeneration in the equatorial Pacific. Model-data comparisons show that the model is able to reproduce many observed features of nitrate, ammonium, such as the deep ammonium maximum (DAM. The model also reproduces the observed de-coupling of ammonium uptake and regeneration, i.e., regeneration rate greater than uptake rate in the lower euphotic zone. The de-coupling largely explains the observed DAM in the equatorial Pacific Ocean. Our study indicates that zooplankton excretion and remineralization of organic nitrogen play a different role in nitrogen regeneration. Rates of zooplankton excretion vary from <0.01 mmol m−3 d−1 to 0.1 mmol m−3 d−1 in the upper euphotic zone while rates of remineralization fall within a narrow range (0.015–0.025 mmol m−3 d−1 . Zooplankton excretion contributes up to 70% of total ammonium regeneration in the euphotic zone, and is largely responsible for the spatial variability of nitrogen regeneration. However, remineralization provides a steady supply of ammonium in the upper ocean, and is a major source of inorganic nitrogen for the oligotrophic regions. Overall, ammonium generation and removal are approximately balanced over the top 150 m in the equatorial Pacific.

  8. Effect of partial root zone drying and deficit irrigation on nitrogen and phosphorus uptake in potato

    DEFF Research Database (Denmark)

    Liu, Caixia; Rubæk, Gitte Holton; Liu, Fulai

    2015-01-01

    Better understanding of the effects of deficit irrigation regimes on phosphorus (P) and nitrogen (N) uptake dynamics is necessary for sustainable water, P and N management. The effects of full (FI), deficit (DI) and partial root-zone drying (PRD) irrigation on potato P and N uptake with P fertili...... was superior to DI in terms of N uptake, but not P uptake. Challenges remain how to maintain crop yield and P uptake under reduced irrigation regimes. Utilization of water and N fertilizer was low when the soil was deficient in P.......Better understanding of the effects of deficit irrigation regimes on phosphorus (P) and nitrogen (N) uptake dynamics is necessary for sustainable water, P and N management. The effects of full (FI), deficit (DI) and partial root-zone drying (PRD) irrigation on potato P and N uptake with P...... fertilization (P1) or without (P0) were investigated in two split-root pot experiments in a soil with low plant available P. Under FI, the plants were irrigated to pot water holding capacity while under DI and PRD, 70% of the water amount of FI was applied on either both or one side of the pots, respectively...

  9. Nocturnal uptake and assimilation of nitrogen dioxide by C3 and CAM plants.

    Science.gov (United States)

    Takahashi, Misa; Konaka, Daisuke; Sakamoto, Atsushi; Morikawa, Hiromichi

    2005-01-01

    In order to investigate nocturnal uptake and assimilation of NO2 by C3 and crassulacean acid metabolism (CAM) plants, they were fumigated with 4 microl l(-1) 15N-labeled nitrogen dioxide (NO2) for 8 h. The amount of NO2 and assimilation of NO2 by plants were determined by mass spectrometry and Kjeldahl-nitrogen based mass spectrometry, respectively. C3 plants such as kenaf (Hibiscus cannabinus), tobacco (Nicotiana tabacum) and ground cherry (Physalis alkekengi) showed a high uptake and assimilation during daytime as high as 1100 to 2700 ng N mg(-1) dry weight. While tobacco and ground cherry strongly reduced uptake and assimilation of NO2 during nighttime, kenaf kept high nocturnal uptake and assimilation of NO2 as high as about 1500 ng N mg(-1) dry weight. Stomatal conductance measurements indicated that there were no significant differences to account for the differences in the uptake of NO2 by tobacco and kenaf during nighttime. CAM plants such as Sedum sp., Kalanchoe blossfeldiana (kalanchoe) and Aloe arborescens exhibited nocturnal uptake and assimilation of NO2. However, the values of uptake and assimilation of NO2 both during daytime and nighttime was very low (at most about 500 ng N mg(-1) dry weight) as compared with those of above mentioned C3 plants. The present findings indicate that kenaf is an efficient phytoremediator of NO2 both during daytime and nighttime.

  10. Nitrogen uptake by size-fractionated phytoplankton in mangrove waters

    Digital Repository Service at National Institute of Oceanography (India)

    Dham, V.V.; Wafar, M.V.M.; Heredia, A.M.

    to January — dry and cool) and pre-monsoon (February to May — dry and hot) periods. Environmental parameters, the nutrients and rates of N uptake and the remineralisation by unfractionated plankton were measured at 3 stations (Fig. 1) over a series of 16... samples with netplankton (20 to 200 µm) and nanoplankton (0.8 to 20 µm) sized particles were obtained by serial filtration through 200 and 20 µm bolting silk and 0.8 µm glass-fibre filters, and were used for measurements of chlorophyll a (chl a...

  11. Natural and anthropogenic nitrogen uptake by bloom-forming macroalgae

    International Nuclear Information System (INIS)

    Thornber, Carol S.; DiMilla, Peter; Nixon, Scott W.; McKinney, Richard A.

    2008-01-01

    The frequency and duration of macroalgal blooms have increased in many coastal waters over the past several decades. We used field surveys and laboratory culturing experiments to examine the nitrogen content and δ 15 N values of Ulva and Gracilaria, two bloom-forming algal genera in Narragansett Bay, RI (USA). The northern end of this bay is densely populated with large sewage treatment plant nitrogen inputs; the southern end is more lightly populated and opens to the Atlantic Ocean. Field-collected Ulva varied in δ 15 N among sites, but with two exceptions had δ 15 N above 10 per mille , reflecting a significant component of heavy anthropogenic N. This variation was not correlated with a north-south gradient. Both Ulva and Gracilaria cultured in water from across Narragansett Bay also had high signals (δ 15 N = ∼14-17 per mille and 8-12 per mille , respectively). These results indicate that inputs of anthropogenic N can have far-reaching impacts throughout estuaries

  12. Natural and anthropogenic nitrogen uptake by bloom-forming macroalgae

    Energy Technology Data Exchange (ETDEWEB)

    Thornber, Carol S. [Department of Biological Sciences, 100 Flagg Road, University of Rhode Island, Kingston, RI 02881 (United States)], E-mail: thornber@uri.edu; DiMilla, Peter; Nixon, Scott W. [Graduate School of Oceanography, University of Rhode Island, South Ferry Road, Narragansett, RI 02881 (United States); McKinney, Richard A. [US Environmental Protection Agency, Atlantic Ecology Division, 27 Tarzwell Drive, Narragansett, RI 02882 (United States)

    2008-02-15

    The frequency and duration of macroalgal blooms have increased in many coastal waters over the past several decades. We used field surveys and laboratory culturing experiments to examine the nitrogen content and {delta}{sup 15}N values of Ulva and Gracilaria, two bloom-forming algal genera in Narragansett Bay, RI (USA). The northern end of this bay is densely populated with large sewage treatment plant nitrogen inputs; the southern end is more lightly populated and opens to the Atlantic Ocean. Field-collected Ulva varied in {delta}{sup 15}N among sites, but with two exceptions had {delta}{sup 15}N above 10 per mille , reflecting a significant component of heavy anthropogenic N. This variation was not correlated with a north-south gradient. Both Ulva and Gracilaria cultured in water from across Narragansett Bay also had high signals ({delta}{sup 15}N = {approx}14-17 per mille and 8-12 per mille , respectively). These results indicate that inputs of anthropogenic N can have far-reaching impacts throughout estuaries.

  13. Natural and anthropogenic nitrogen uptake by bloom-forming macroalgae.

    Science.gov (United States)

    Thornber, Carol S; DiMilla, Peter; Nixon, Scott W; McKinney, Richard A

    2008-02-01

    The frequency and duration of macroalgal blooms have increased in many coastal waters over the past several decades. We used field surveys and laboratory culturing experiments to examine the nitrogen content and delta(15)N values of Ulva and Gracilaria, two bloom-forming algal genera in Narragansett Bay, RI (USA). The northern end of this bay is densely populated with large sewage treatment plant nitrogen inputs; the southern end is more lightly populated and opens to the Atlantic Ocean. Field-collected Ulva varied in delta(15)N among sites, but with two exceptions had delta(15)N above 10 per thousand, reflecting a significant component of heavy anthropogenic N. This variation was not correlated with a north-south gradient. Both Ulva and Gracilaria cultured in water from across Narragansett Bay also had high signals (delta(15)N= approximately 14-17 per thousand and 8-12 per thousand, respectively). These results indicate that inputs of anthropogenic N can have far-reaching impacts throughout estuaries.

  14. Fire effects on the mobilization and uptake of nitrogen by cheatgrass (Bromus tectorum L.)

    Science.gov (United States)

    Brittany G. Johnson; Dale W. Johnson; Jeanne C. Chambers; Robert R. Blank

    2011-01-01

    Cheatgrass (Bromus tectorum L.), an invasive annual grass, is displacing native species and causing increased fire frequency in the Great Basin of the southwestern United States. Growth and nitrogen uptake patterns by cheatgrass were examined in a greenhouse study using soils from sites with the same soil type but different fire histories: 1) an area that burned in...

  15. Nitrogen uptake and rate-limiting step in low-temperature nitriding of iron

    NARCIS (Netherlands)

    Inia, DK; Vredenberg, AM; Habraken, FHPM; Boerma, DO

    1999-01-01

    Recently, a method to nitride iron in NH3 ambients at low temperature (225-350 degrees C) has been developed. In this method, the Fe is covered with a thin (similar to 40 nm) Ni layer, which acts as a catalyst for the nitriding process. From experiments, in which the amount of nitrogen uptake is

  16. f-Ratios calculated with and without urea uptake in nitrogen uptake by phytoplankton

    Digital Repository Service at National Institute of Oceanography (India)

    Wafar, M.V.M.; Corre, P.L.; L'Helguen, S.

    . Peterson (1979) Particulate organic matter Hux and planktonic new production in the deep ocean. Nature, 282,677-6X0. Epplcy R. W., .I. H. Sharp, E. H. Renger, M. J. Perry and W. G. Harrison (1977) Nitrogen assimilation by phytoplankton and other... f’rogress Serres. 67, 275-2X3. Harrison W. G.. I_. R. Harris, D. M. Karl. G. A. Knauer and D. G. Redaljc (1992) Nitrogen dynamics at the Vcrtcx time-series site. DeepSea Revearch. 39, 1.535-1557. Harvey W. A. and J. Caperon (1976) The rate...

  17. Contributions of secondary forest and nitrogen dynamics to terrestrial carbon uptake

    Directory of Open Access Journals (Sweden)

    X. Yang

    2010-10-01

    Full Text Available We use a terrestrial carbon-nitrogen cycle component of the Integrated Science Assessment Model (ISAM to investigate the impacts of nitrogen dynamics on regrowing secondary forests over the 20th century. We further examine what the impacts of nitrogen deposition and land use change history are on terrestrial carbon uptake since preindustrial time. Our results suggest that global total net land use emissions for the 1990s associated with changes in cropland, pastureland, and wood harvest are 1.22 GtC/yr. Without considering the secondary forest regrowth, the estimated net global total land use emissions are 1.58 GtC/yr or about 0.36 GtC/yr higher than if secondary forest regrowth is considered. Results also show that without considering the nitrogen dynamics and deposition, the estimated global total secondary forest sink for the 1990s is 0.90 GtC/yr or about 0.54 GtC/yr higher than estimates that include the impacts of nitrogen dynamics and deposition. Nitrogen deposition alone is responsible for about 0.13 GtC/yr of the total secondary forest sink. While nitrogen is not a limiting nutrient in the intact primary forests in tropical regions, our study suggests that nitrogen becomes a limiting nutrient for regrowing secondary forests of the tropical regions, in particular Latin America and Tropical Africa. This is because land use change activities, especially wood harvest, removes large amounts of nitrogen from the system when slash is burnt or wood is removed for harvest. However, our model results show that carbon uptake is enhanced in the tropical secondary forests of the Indian region. We argue that this may be due to enhanced nitrogen mineralization and increased nitrogen availability following land use change in the Indian tropical forest ecosystems. Results also demonstrate that there is a significant amount of carbon accumulating in the Northern Hemisphere where most land use changes and forest regrowth has occurred in recent decades

  18. Improving efficiencies of irrigation and nitrogen uptake in wheat

    International Nuclear Information System (INIS)

    Bazza, M.

    2000-01-01

    Three years of field studies and lysimeter experiments on irrigated wheat had the objective of finding ways of managing irrigation and N fertilization to minimize losses and reduce contamination of groundwater. Applied N had significant positive effects on crop-water consumptive use. The highest N losses occurred during early growth. Irrigation had little effect on N loss when it was practiced efficiently. Under the prevailing conditions, it is recommended that no N be applied to wheat at planting, in order to limit N losses by leaching caused by the high precipitation that usually occurs during early development when crop-N requirements are small. No more than 120 kg N ha -1 should be applied in total to minimize groundwater pollution and maximize N-uptake efficiency and economic returns. Also, for economic and environmental reasons, irrigation should be limited to 80% of the total requirement and to depths of 40 to 60 mm. (author)

  19. Studies on nitrogen uptake and utilization by rape (Brassica napus L.) under different sowing dates

    International Nuclear Information System (INIS)

    Liu Qixin; Nie Guangming

    1992-01-01

    The nitrogen uptake and utilization by low erucic acid variety, Zhong You Di Gai No.2, of rape (Brassica napus L.) under different sowing dates were studied. Total N uptake, the percentage N derived from the fertilizer, the rate of utilization of nitrogenous fertilizer, the production efficiency of N-fertilizer (seed yield g/gN derived by rape plant from the fertilizer), total P uptake and the production efficiency of phosphorus (seed yield g/gP derived by rape plant from fertilizer and soil) were all significantly higher at early sowing than that at later sowing within the range of normal sowing dates. Therefore, the biomass yield, the seed yield and oil content all increased significantly at early sowing treatment, but erucic acid content showed no significant difference

  20. Contributing factors in foliar uptake of dissolved inorganic nitrogen at leaf level

    Energy Technology Data Exchange (ETDEWEB)

    Wuyts, Karen, E-mail: karen.wuyts@uantwerpen.be [Laboratory of Environmental and Urban Ecology, Research Group ENdEMIC, Dept. Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Forest and Nature Lab (ForNaLab), Dept. Forest and Water Management, Ghent University, Geraardsbergsesteenweg 267, B-9090 Gontrode-Melle (Belgium); Adriaenssens, Sandy, E-mail: adriaenssens@irceline.be [Belgian Interregional Environment Agency (IRCEL-CELINE), Kunstlaan 10–11, B-1210 Brussels (Belgium); Staelens, Jeroen, E-mail: jeroen_staelens@yahoo.com [Flemish Environment Agency (VMM), Kronenburgstraat 45, B-2000 Antwerp (Belgium); Wuytack, Tatiana, E-mail: tatiana.wuytack@uantwerpen.be [Laboratory of Environmental and Urban Ecology, Research Group ENdEMIC, Dept. Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Van Wittenberghe, Shari, E-mail: shari.vanwittenberghe@uantwerpen.be [Laboratory of Environmental and Urban Ecology, Research Group ENdEMIC, Dept. Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Boeckx, Pascal, E-mail: pascal.boeckx@ugent.be [Isotope Bioscience Laboratory (ISOFYS), Dept. Applied Analytical and Physical Chemistry, Ghent University, Coupure Links 653, B-9000 Ghent (Belgium); Samson, Roeland, E-mail: roeland.samson@uantwerpen.be [Laboratory of Environmental and Urban Ecology, Research Group ENdEMIC, Dept. Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Verheyen, Kris, E-mail: kris.verheyen@ugent.be [Forest and Nature Lab (ForNaLab), Dept. Forest and Water Management, Ghent University, Geraardsbergsesteenweg 267, B-9090 Gontrode-Melle (Belgium)

    2015-02-01

    We investigated the influence of leaf traits, rainwater chemistry, and pedospheric nitrogen (N) fertilisation on the aqueous uptake of inorganic N by physiologically active tree leaves. Leaves of juvenile silver birch and European beech trees, supplied with NH{sub 4}NO{sub 3} to the soil at rates from 0 to 200 kg N ha{sup −1} y{sup −1}, were individually exposed to 100 μl of artificial rainwater containing {sup 15}NH{sub 4}{sup +} or {sup 15}NO{sub 3}{sup −} at two concentration levels for one hour. In the next vegetative period, the experiment was repeated with NH{sub 4}{sup +} at the highest concentration only. The N form and the N concentration in the applied rainwater and, to a lesser extent, the pedospheric N treatment and the leaf traits affected the aqueous foliar N uptake. The foliar uptake of NH{sub 4}{sup +} by birch increased when leaves were more wettable. High leaf N concentration and leaf mass per area enhanced the foliar N uptake, and NO{sub 3}{sup −} uptake in particular, by birch. Variation in the foliar N uptake by the beech trees could not be explained by the leaf traits considered. In the first experiment, N fertilisation stimulated the foliar N uptake in both species, which was on average 1.42–1.78 times higher at the highest soil N dose than at the zero dose. However, data variability was high and the effect was not appreciable in the second experiment. Our data suggest that next to rainwater chemistry (N form and concentration) also forest N status could play a role in the partitioning of N entering the ecosystem through the soil and the canopy. Models of canopy uptake of aqueous N at the leaf level should take account of leaf traits such as wettability and N concentration. - Highlights: • Foliar uptake of dissolved inorganic nitrogen (N) by potted trees was studied. • Leaves were individually exposed to rainwater drops containing {sup 15}NH{sub 4}{sup +} or {sup 15}NO{sub 3}{sup −}. • Foliar N uptake efficiency depended on

  1. Understanding nitrate uptake, signaling and remobilisation for improving plant nitrogen use efficiency.

    Science.gov (United States)

    Kant, Surya

    2018-02-01

    The majority of terrestrial plants use nitrate as their main source of nitrogen. Nitrate also acts as an important signalling molecule in vital physiological processes required for optimum plant growth and development. Improving nitrate uptake and transport, through activation by nitrate sensing, signalling and regulatory processes, would enhance plant growth, resulting in improved crop yields. The increased remobilisation of nitrate, and assimilated nitrogenous compounds, from source to sink tissues further ensures higher yields and quality. An updated knowledge of various transporters, genes, activators, and microRNAs, involved in nitrate uptake, transport, remobilisation, and nitrate-mediated root growth, is presented. An enhanced understanding of these components will allow for their orchestrated fine tuning in efforts to improving nitrogen use efficiency in plants. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  2. In Situ Denitrification and Biological Nitrogen Fixation Under Enhanced Atmospheric Reactive Nitrogen Deposition in UK Peatlands

    Science.gov (United States)

    Ullah, Sami; Saiz Val, Ernesto; Sgouridis, Fotis; Peichl, Matthias; Nilsson, Mats

    2017-04-01

    Dinitrogen (N2) and nitrous oxide (N2O) losses due to denitrification and biological N2 fixation (BNF) are the most uncertain components of the nitrogen (N) cycle in peatlands under enhanced atmospheric reactive nitrogen (Nr) deposition. This uncertainty hampers our ability to assess the contribution of denitrification to the removal of biologically fixed and/or atmospherically deposited Nr in peatlands. This uncertainty emanates from the difficulty in measuring in situ soil N2 and N2O production and consumption in peatlands. In situ denitrification and its contribution to total N2O flux was measured monthly between April 2013 and October 2014 in peatlands in two UK catchments. An adapted 15N-Gas Flux method1 with low level addition of 15N tracer (0.03 ± 0.005 kg 15N ha-1) was used to measure denitrification and its contribution to net N2O production (DN2O/TN2O). BNF was measured in situ through incubation of selected sphagnum species under 15N2 gas tracer. Denitrification2 varied temporally and averaged 8 kg N-N2 ha-1 y-1. The contribution of denitrification was about 48% to total N2O flux3 of 0.05 kg N ha-1 y-1. Soil moisture, temperature, ecosystem respiration, pH and mineral N content mainly regulated the flux of N2 and N2O. Preliminary results showed suppression of BNF, which was 1.8 to 7 times lower in peatland mosses exposed to ˜15 to 20 kg N ha-1 y-1 Nr deposition in the UK than in peatland mosses in northern Sweden with background Nr deposition. Overall, the contribution of denitrification to Nr removal in the selected peatlands was ˜50% of the annual Nr deposition rates, making these ecosystems vulnerable to chronic N saturation. These results point to a need for a more comprehensive annual BNF measurement to more accurately account for total Nr input into peatlands and its atmospheric loss due to denitrification. References Sgouridis F, Stott A & Ullah S, 2016. Application of the 15N-Gas Flux method for measuring in situ N2 and N2O fluxes due to

  3. Nitrogen isotope fractionation during N uptake via arbuscular mycorrhizal and ectomycorrhizal fungi into grey alder.

    Science.gov (United States)

    Schweiger, Peter F

    2016-10-20

    Arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) fungi affect plant nitrogen (N) dynamics. Plant N isotope patterns have been used to characterise the contribution of ECM fungi to plant N uptake. By quantifying and comparing the effects of an AM and an ECM fungus on growth, N uptake and isotopic composition of one host plant grown at different relative N supply levels, the aim of this study was to improve the mechanistic understanding of natural 15 N abundance patterns in mycorrhizal plants and their underlying causes. Grey alders were inoculated with one ECM fungus or one AM fungus or left non-mycorrhizal. Plants were grown under semi-hydroponic conditions and were supplied with three rates of relative N supply ranging from deficient to luxurious. Neither mycorrhizal fungus increased plant growth or N uptake. AM root colonisation had no effect on whole plant δ 15 N and decreased foliar δ 15 N only under N deficiency. The roots of these plants were 15 N-enriched. ECM root colonisation consistently decreased foliar and whole plant δ 15 N. It is concluded, that both mycorrhizal fungi contributed to plant N uptake into the shoot. Nitrogen isotope fractionation during N assimilation and transformations in fungal mycelia is suggested to have resulted in plants receiving 15 N-depleted N via the mycorrhizal uptake pathways. Negative mycorrhizal growth effects are explained by symbiotic resource trade on carbon and N and decreased direct plant N uptake. Copyright © 2016 Elsevier GmbH. All rights reserved.

  4. Elevated CO2 plus chronic warming reduce nitrogen uptake and levels or activities of nitrogen-uptake and -assimilatory proteins in tomato roots.

    Science.gov (United States)

    Jayawardena, Dileepa M; Heckathorn, Scott A; Bista, Deepesh R; Mishra, Sasmita; Boldt, Jennifer K; Krause, Charles R

    2017-03-01

    Atmospheric CO 2 enrichment is expected to often benefit plant growth, despite causing global warming and nitrogen (N) dilution in plants. Most plants primarily procure N as inorganic nitrate (NO 3 - ) or ammonium (NH 4 + ), using membrane-localized transport proteins in roots, which are key targets for improving N use. Although interactive effects of elevated CO 2 , chronic warming and N form on N relations are expected, these have not been studied. In this study, tomato (Solanum lycopersicum) plants were grown at two levels of CO 2 (400 or 700 ppm) and two temperature regimes (30 or 37°C), with NO 3 - or NH 4 + as the N source. Elevated CO 2 plus chronic warming severely inhibited plant growth, regardless of N form, while individually they had smaller effects on growth. Although %N in roots was similar among all treatments, elevated CO 2 plus warming decreased (1) N-uptake rate by roots, (2) total protein concentration in roots, indicating an inhibition of N assimilation and (3) shoot %N, indicating a potential inhibition of N translocation from roots to shoots. Under elevated CO 2 plus warming, reduced NO 3 - -uptake rate per g root was correlated with a decrease in the concentration of NO 3 - -uptake proteins per g root, reduced NH 4 + uptake was correlated with decreased activity of NH 4 + -uptake proteins and reduced N assimilation was correlated with decreased concentration of N-assimilatory proteins. These results indicate that elevated CO 2 and chronic warming can act synergistically to decrease plant N uptake and assimilation; hence, future global warming may decrease both plant growth and food quality (%N). © 2016 Scandinavian Plant Physiology Society.

  5. Nitrogen and Phosphorus Plant Uptake During Periods with no Photosynthesis Accounts for About Half of Global Annual Uptake

    Science.gov (United States)

    Riley, W. J.; Zhu, Q.; Tang, J.

    2017-12-01

    Uncertainties in current Earth System Model (ESM) predictions of terrestrial carbon-climate feedbacks over the 21st century are as large as, or larger than, any other reported natural system uncertainties. Soil Organic Matter (SOM) decomposition and photosynthesis, the dominant fluxes in this regard, are tightly linked through nutrient availability, and the recent Coupled Model Inter-comparison Project 5 (CMIP5) used for climate change assessment had no credible representations of these constraints. In response, many ESM land models (ESMLMs) have developed dynamic and coupled soil and plant nutrient cycles. Here we quantify terrestrial carbon cycle impacts from well-known observed plant nutrient uptake mechanisms ignored in most current ESMLMs. In particular, we estimate the global role of plant root nutrient competition with microbes and abiotic process at night and during the non-growing season using the ACME land model (ALMv1-ECA-CNP) that explicitly represents these dynamics. We first demonstrate that short-term nutrient uptake dynamics and competition between plants and microbes are accurately predicted by the model compared to 15N and 33P isotopic tracer measurements from more than 20 sites. We then show that global nighttime and non-growing season nitrogen and phosphorus uptake accounts for 46 and 45%, respectively, of annual uptake, with large latitudinal variation. Model experiments show that ignoring these plant uptake periods leads to large positive biases in annual N leaching (globally 58%) and N2O emissions (globally 68%). Biases these large will affect modeled carbon cycle dynamics over time, and lead to predictions of ecosystems that have overly open nutrient cycles and therefore lower capacity to sequester carbon.

  6. Land use/land cover and scale influences on in-stream nitrogen uptake kinetics

    Science.gov (United States)

    Covino, Tim; McGlynn, Brian; McNamara, Rebecca

    2012-06-01

    Land use/land cover change often leads to increased nutrient loading to streams; however, its influence on stream ecosystem nutrient transport remains poorly understood. Given the deleterious impacts elevated nutrient loading can have on aquatic ecosystems, it is imperative to improve understanding of nutrient retention capacities across stream scales and watershed development gradients. We performed 17 nutrient addition experiments on six streams across the West Fork Gallatin Watershed, Montana, USA, to quantify nitrogen uptake kinetics and retention dynamics across stream sizes (first to fourth order) and along a watershed development gradient. We observed that stream nitrogen (N) uptake kinetics and spiraling parameters varied across streams of different development intensity and scale. In more developed watersheds we observed a fertilization affect. This fertilization affect was evident as increased ash-free dry mass, chlorophylla, and ambient and maximum uptake rates in developed as compared to undeveloped streams. Ash-free dry mass, chlorophylla, and the number of structures in a subwatershed were significantly correlated to nutrient spiraling and kinetic parameters, while ambient and average annual N concentrations were not. Additionally, increased maximum uptake capacities in developed streams contributed to low in-stream nutrient concentrations during the growing season, and helped maintain watershed export at low levels during base flow. Our results indicate that land use/land cover change can enhance in-stream uptake of limiting nutrients and highlight the need for improved understanding of the watershed dynamics that control nutrient export across scales and development intensities for mitigation and protection of aquatic ecosystems.

  7. Seasonal temperatures have more influence than nitrogen fertilizer rates on cucumber yield and nitrogen uptake in a double cropping system

    International Nuclear Information System (INIS)

    Guo Ruiying; Li Xiaolin; Christie, Peter; Chen Qing; Zhang Fusuo

    2008-01-01

    Two-year greenhouse cucumber experiments were conducted to investigate seasonal effects on fruit yield, dry matter allocation, and N uptake in a double-cropping system with different fertilizer management. Seasonal effects were much greater than fertilizer effects, and winter-spring (WS) cucumber attained higher fruit yields and N uptake than autumn-winter (AW) cucumber due to lower cumulative air temperatures during fruit maturation in the AW season. Fertilizer N application and apparent N loss under recommended N management (Nmr) decreased by 40-78% and 33-48% without yield loss compared to conventional N management (Nmt) over four growing seasons. However, there were no seasonal differences in N recommendations, taking into consideration seasonal differences in crop N demand, critical nutrient supply in the root zone and N mineralization rate. - Nitrogen inputs can be reduced to minimize N losses to the environment while maintaining yields but N recommendations must reflect seasonal temperature effects

  8. Seasonal temperatures have more influence than nitrogen fertilizer rates on cucumber yield and nitrogen uptake in a double cropping system

    Energy Technology Data Exchange (ETDEWEB)

    Guo Ruiying; Li Xiaolin [College of Resources and Environmental Sciences, China Agricultural University, No. 2 Yuanmingyuan Xilu, Haidian District, Beijing 100094 (China); Christie, Peter [College of Resources and Environmental Sciences, China Agricultural University, No. 2 Yuanmingyuan Xilu, Haidian District, Beijing 100094 (China); Agricultural and Environmental Science Department, Queen' s University Belfast, Belfast BT9 5PX (United Kingdom); Chen Qing [College of Resources and Environmental Sciences, China Agricultural University, No. 2 Yuanmingyuan Xilu, Haidian District, Beijing 100094 (China)], E-mail: qchen@cau.edu.cn; Zhang Fusuo [College of Resources and Environmental Sciences, China Agricultural University, No. 2 Yuanmingyuan Xilu, Haidian District, Beijing 100094 (China)

    2008-02-15

    Two-year greenhouse cucumber experiments were conducted to investigate seasonal effects on fruit yield, dry matter allocation, and N uptake in a double-cropping system with different fertilizer management. Seasonal effects were much greater than fertilizer effects, and winter-spring (WS) cucumber attained higher fruit yields and N uptake than autumn-winter (AW) cucumber due to lower cumulative air temperatures during fruit maturation in the AW season. Fertilizer N application and apparent N loss under recommended N management (Nmr) decreased by 40-78% and 33-48% without yield loss compared to conventional N management (Nmt) over four growing seasons. However, there were no seasonal differences in N recommendations, taking into consideration seasonal differences in crop N demand, critical nutrient supply in the root zone and N mineralization rate. - Nitrogen inputs can be reduced to minimize N losses to the environment while maintaining yields but N recommendations must reflect seasonal temperature effects.

  9. Variation in summer nitrogen and phosphorus uptake among Siberian headwater streams

    Directory of Open Access Journals (Sweden)

    John D. Schade

    2016-06-01

    Full Text Available Arctic streams are likely to receive increased inputs of dissolved nutrients and organic matter from thawing permafrost as climate warms. Documenting how Arctic streams process inorganic nutrients is necessary to understand mechanisms that regulate watershed fluxes of permafrost-derived materials to downstream ecosystems. We report on summer nitrogen (N and phosphorus (P uptake in streams draining upland soils from the Pleistocene, and lowland floodplain soils from the Holocene, in Siberia's Kolyma River watershed. Uptake of N and P differed between upland and floodplain streams, suggesting topographic variation in nutrient limitation. In floodplain streams, P uptake rate and uptake velocity were higher than N, while upland streams had similar values for all N and P uptake metrics. Phosphorus uptake velocity and size of the transient hydrologic storage zone were negatively related across all study streams, indicating strong influence of hydrologic processes on nutrient fluxes. Physical sorption of P was higher in floodplain stream sediments relative to upland stream sediments, suggesting more physically driven uptake in floodplain streams and higher biological activity in upland streams. Overall, these results demonstrate that high-latitude headwater streams actively retain N and P during summer base flows; however, floodplain and upland streams varied substantially in N and P uptake and may respond differently to inorganic nutrient and organic matter inputs. Our results highlight the need for a comprehensive assessment of N and P uptake and retention in Arctic streams in order to fully understand the impact of permafrost-derived materials on ecosystem processes, and their fate in continental drainage networks.

  10. Relationships between streamwater nitrogen and primary uptake compartments: an isotopic approach

    OpenAIRE

    Pastor Oliveras, Ada

    2014-01-01

    The overarching goal of this dissertation was to explore relationships between streamwater nitrogen (N) and the most representative primary uptake compartments (PUCs) in stream ecosystems (e.g. microbial biofilm, algae, bryophytes, macrophytes). In particular, environmental factors driving these biogeochemical relationships along a strong anthropogenic gradient were explored and differences among and within PUC types were compared. To elucidate the factors controlling these relationships, we ...

  11. Host-derived viral transporter protein for nitrogen uptake in infected marine phytoplankton

    Science.gov (United States)

    Chambouvet, Aurélie; Milner, David S.; Attah, Victoria; Terrado, Ramón; Lovejoy, Connie; Moreau, Hervé; Derelle, Évelyne; Richards, Thomas A.

    2017-01-01

    Phytoplankton community structure is shaped by both bottom–up factors, such as nutrient availability, and top–down processes, such as predation. Here we show that marine viruses can blur these distinctions, being able to amend how host cells acquire nutrients from their environment while also predating and lysing their algal hosts. Viral genomes often encode genes derived from their host. These genes may allow the virus to manipulate host metabolism to improve viral fitness. We identify in the genome of a phytoplankton virus, which infects the small green alga Ostreococcus tauri, a host-derived ammonium transporter. This gene is transcribed during infection and when expressed in yeast mutants the viral protein is located to the plasma membrane and rescues growth when cultured with ammonium as the sole nitrogen source. We also show that viral infection alters the nature of nitrogen compound uptake of host cells, by both increasing substrate affinity and allowing the host to access diverse nitrogen sources. This is important because the availability of nitrogen often limits phytoplankton growth. Collectively, these data show that a virus can acquire genes encoding nutrient transporters from a host genome and that expression of the viral gene can alter the nutrient uptake behavior of host cells. These results have implications for understanding how viruses manipulate the physiology and ecology of phytoplankton, influence marine nutrient cycles, and act as vectors for horizontal gene transfer. PMID:28827361

  12. Root distribution pattern and nitrogen uptake of some wheat and triticale germplasms in relation to rates and methods of nitrogen application

    International Nuclear Information System (INIS)

    Meena, N.L.; Seth, Jagdish

    1975-01-01

    A field experiment was conducted under irrigated conditions with four germplasms viz. Triticale(70-2), and wheat varieties HD 4502(durum), Kalyan Sona and Moti (aestivums) at the Indian Agricultural Research Institute Farm, New Delhi, during rabi season of 1972-73. The treatments comprised of three rates of nitrogen viz. 0,60 and 120 kg/ha and two methods of nitrogen application viz. (1) soil + foliar and (2) soil. The root distribution of the four germplasms, studied by 32 P injection technique was increased both vertically and horizontally with the addition of nitrogen. Root distribution of triticale was observed to be deep and spreading in habit, while durum proved to be shallow rooted and compact in nature. The total uptake of nitrogen was significantly increased with higher rates of nitrogen in all the germplasms. The maximum uptake of nitrogen was observed in the durum wheat. (author)

  13. Increasing plant use of organic nitrogen with elevation is reflected in nitrogen uptake rates and ecosystem delta15N.

    Science.gov (United States)

    Averill, Colin; Finzi, Adrien

    2011-04-01

    It is hypothesized that decreasing mean annual temperature and rates of nitrogen (N) cycling causes plants to switch from inorganic to organic forms of N as the primary mode of N nutrition. To test this hypothesis, we conducted field experiments and collected natural-abundance delta15N signatures of foliage, soils, and ectomycorrhizal sporocarps along a steep elevation-climate gradient in the White Mountains, New Hampshire, USA. Here we show that with increasing elevation organic forms of N became the dominant source of N taken up by hardwood and coniferous tree species based on dual-labeled glycine uptake analysis, an important confirmation of an emerging theory for the biogeochemistry of the N cycle. Variation in natural abundance foliar delta15N with elevation was also consistent with increasing organic N uptake, though a simple, mass balance model demonstrated that the uptake of delta15N depleted inorganic N, rather than fractionation upon transfer of N from mycorrhizal fungi, best explains variations in foliar delta15N with elevation.

  14. Dry matter yield and nitrogen-15 uptake by tomatoes under sodium chloride stress

    International Nuclear Information System (INIS)

    Pessarakli, M.; Tucker, T.C.

    1988-01-01

    An absorption study was conducted in nutrient solution with seedlings of tomato (Lycopersicon esculentum Mill; cv. Columbia) to observe the effects of NaCl on ( 15 N) uptake and distribution in plant roots and shoots. The 14-d-old seedlings were grown for 16 d in complete Hoagland solution no. 1, then salinized (except the controls, -0.03 MPa) to -0.3, -0.6, and -0.9 MPa osmotic potentials with NaCl. Nutrient solutions were sampled daily for N loss after addition of 15 NH 4 15 NO 3 to the pots. The cumulative 15 N loss was considered to be absorbed by plants. Lowering the osmotic potential of the culture solution decreased total N uptake at all salinity levels, and 15 N uptake of the plants at medium and high salinity levels. A low level of salinity did not affect 15 N uptake compared with the control. Water uptake and dry matter yield were affected to a greater extent than 15 N absorption. Nitrogen-15 concentration was slightly higher in roots than in shoots

  15. Carbon and nitrogen uptake of calcareous benthic foraminifera along a depth-related oxygen gradient in the OMZ of the Arabian Sea

    Directory of Open Access Journals (Sweden)

    Annekatrin Julie Enge

    2016-02-01

    Full Text Available Foraminifera are an important faunal element of the benthos in oxygen-depleted settings such as Oxygen Minimum Zones (OMZs where they can play a relevant role in the processing of phytodetritus. We investigated the uptake of phytodetritus (labeled with 13C and 15N by cal-careous foraminifera in the 0-1 cm sediment horizon under different oxygen concentrations within the OMZ in the eastern Arabian Sea. The in situ tracer experiments were carried out along a depth transect on the Indian margin over a period of 4 to 10 days. The uptake of phy-todetrital carbon within 4 days by all investigated species shows that phytodetritus is a rele-vant food source for foraminifera in OMZ sediments. The decrease of total carbon uptake from 540 to 1100 m suggests a higher demand for carbon by species in the low-oxygen core region of the OMZ or less food competition with macrofauna. Especially Uvigerinids showed high uptake of phytodetrital carbon at the lowest oxygenated site. Variation in the ratio of phytodetrital carbon to nitrogen between species and sites indicates that foraminiferal carbon and nitrogen use can be decoupled and different nutritional demands are found between spe-cies. Lower ratio of phytodetrital carbon and nitrogen at 540 m could hint for greater demand or storage of food-based nitrogen, ingestion or hosting of bacteria under almost anoxic condi-tions. Shifts in the foraminiferal assemblage structure (controlled by oxygen or food availabil-ity and in the presence of other benthic organisms account for observed changes in the pro-cessing of phytodetritus in the different OMZ habitats. Foraminifera dominate the short-term processing of phytodetritus in the OMZ core but are less important in the lower OMZ bounda-ry region of the Indian margin as biological interactions and species distribution of foraminif-era change with depth and oxygen levels.

  16. Forest canopy uptake of atmospheric nitrogen deposition at eastern U.S. conifer sites: Carbon storage implications?

    Science.gov (United States)

    Herman Sievering; Ivan Fernandez; John Lee; John Hom; Lindsey Rustad

    2000-01-01

    Dry deposition determinations, along with wet deposition and throughfall (TF) measurements, at a spruce fir forest in central Maine were used to estimate the effect of atmospherically deposited nitrogen (N) uptake on forest carbon storage. Using nitric acid and particulate N as well as TF ammonium and nitrate data, the growing season (May-October) net canopy uptake of...

  17. Intercropping effect on root growth and nitrogen uptake at different nitrogen levels

    DEFF Research Database (Denmark)

    Ramirez-Garcia, Javier; Martens, Helle Juel; Quemada, Miguel

    2015-01-01

    of root growth and N foraging for barley (Hordeum vulgare L.) and vetch (Vicia sativa L.), frequently grown in mixtures as cover crops. N was added at 0 (N0), 50 (N1) and 150 (N2) kg N ha−1. The roots discrimination relying on the anatomical and morphological differences observed between dicots......Aims Intercropping legumes and non-legumes may affect the root growth of both components in the mixture, and the non-legume is known to be strongly favored by increasing nitrogen (N) supply. The knowledge of how root systems affect the growth of the individual species is useful for understanding...... the interactions in intercrops as well as for planning cover cropping strategies. The aim of this work was (i) to determine if different levels of N in the topsoil influence root depth (RD) and intensity of barley and vetch as sole crops or as an intercropped mixture and (ii) to test if the choice of a mixture...

  18. Effect of nitrogen, potassium and lime on soil and manganese availability and uptake by bean

    International Nuclear Information System (INIS)

    Muraoka, T.; Nascimento Filho, V.F. do; Salvador, J.O.

    1982-01-01

    A pot experiment was conducted to assess the effect of nitrogen, potassium and lime on the availability of soil Zn and Mn and the absorption of these elements by bean (Phaseolus vulgaris, L.). The TE (Terra Roxa Estruturada) soil, used in this experiment, had been uniformily labelled with 65 Zn and 54 Mn and incubated prior to the seeding. The nitrogen favoured the absorption of manganese and zinc, tripling the manganese content in the plant and increasing by 2.5 fold the Zn content. The potassium also increased significantly the manganese uptake, but did not affect the zinc uptake. In the case of the Zn, however, the effect continued, though with less intensity. The lime alone reduced by almost 5 times the Mn content in the plant and by 50% the Zn content. Based on the results of the soil analysis (pH, CaCl 2 O.5M extractable Mn and EDTA + CaCl 2 extractable Zn) and on the 65 Zn and 54 Mn specific activities, it is suggested that the effets of nitrogen and potassium could be, partly, of synergic nature and that of the lime, due, also partly, to Ca-Mn and Ca-Zn antagonism in the plant. (Author) [pt

  19. Arbuscular mycorrhiza improve growth, nitrogen uptake, and nitrogen use efficiency in wheat grown under elevated CO2

    DEFF Research Database (Denmark)

    Zhu, Xiancan; Song, Fengbin; Liu, Shengqun

    2016-01-01

    Effects of the arbuscular mycorrhizal (AM) fungus Rhizophagus irregularis on plant growth, carbon (C) and nitrogen (N) accumulation, and partitioning was investigated in Triticum aestivum L. plants grown under elevated CO2 in a pot experiment. Wheat plants inoculated or not inoculated with the AM...... and higher plant biomass than the non-AM plants. CO2 elevation did not affect C and N partitioning in plant organs, while AM symbiosis increased C and N allocation into the roots. In addition, plant C and N accumulation, (15)N recovery rate, and N use efficiency (NUE) were significantly higher in AM plants...... than in non-AM controls under CO2 enrichment. It is concluded that AM symbiosis favors C and N partitioning in roots, increases C accumulation and N uptake, and leads to greater NUE in wheat plants grown at elevated CO2....

  20. Interactions between uptake of amino acids and inorganic nitrogen in wheat plants

    Directory of Open Access Journals (Sweden)

    E. Gioseffi

    2012-04-01

    Full Text Available Soil-borne amino acids may constitute a source of nitrogen (N for plants in various terrestrial ecosystems but their importance for total N nutrition is unclear, particularly in nutrient-rich arable soils. One reason for this uncertainty is lack of information on how the absorption of amino acids by plant roots is affected by the simultaneous presence of inorganic N forms. The objective of the present study was to study absorption of glycine (Gly and glutamine (Gln by wheat roots and their interactions with nitrate (NO3 and ammonium (NH4+ during uptake. The underlying hypothesis was that amino acids, when present in nutrient solution together with inorganic N, may lead to down-regulation of the inorganic N uptake, thereby resulting in similar total N uptake rates. Amino acids were enriched with double-labelled 15N and 13C, while NO3 and NH4+ acquisition was determined by their rate of removal from the nutrient solution surrounding the roots. The uptake rates of NO3 and NH4+ did not differ from each other and were generally about twice as high as the uptake rate of organic N when the different N forms were supplied separately in concentrations of 2 mM. Nevertheless, replacement of 50% of the inorganic N with organic N was able to restore the N uptake to the same level as that in the presence of only inorganic N. Co-provision of NO3 did not affect glycine uptake, while the presence of glycine down-regulated NO3 uptake. The ratio between 13C and 15N were lower in shoots than in roots and also lower than the theoretical values, reflecting higher C losses via respiratory processes compared to N losses. It is concluded that organic N can constitute a significant N-source for wheat plants and that there is an interaction

  1. Interaction of different irrigation strategies and soil textures on the nitrogen uptake of field grown potatoes

    DEFF Research Database (Denmark)

    Ahmadi, S.H.; Andersen, Mathias Neumann; Lærke, Poul Erik

    2011-01-01

    Nitrogen (N) uptake (kg ha-1) of field-grown potatoes was measured in 4.32 m2 lysimeters that were filled with coarse sand, loamy sand, and sandy loam and subjected to full (FI), deficit (DI), and partial root-zone drying (PRD) irrigation strategies. PRD and DI as water-saving irrigation treatments...... in the loamy sand had the highest amount of N uptake. The interaction between irrigation treatments and soil textures was significant, and implied that under non-limiting water conditions, loamy sand is the suitable soil for potato production because plants can take up sufficient amounts of N and it could...... potentially lead to higher yield. However, under limited water conditions and applying water-saving irrigation strategies, sandy loam and coarse sand are better growth media because N is more available for the potatoes. The simple yield prediction model was developed that could explains ca. 96...

  2. Influence of the form and rate of 15N-labelled nitrogen fertilizers on nitrogen uptake by maize grown on two different soils

    International Nuclear Information System (INIS)

    Balabanova-Georgieva, R.; Ikonomova, E.

    1996-01-01

    The influence of 15 N-labelled urea and ammonium sulfate on the yield and uptake of fertilizer nitrogen and soil nitrogen by maize was studied under the conditions of pot experiments on calcareous black earth and leached black earth. The nitrogen fertilizers were applied in rates: N 1 =250 mg, N 2 =500 mg, N 3 =750 mg and N 4 =1000 mg/1 kg of soil, on phosphorus(P)-potassium(K) background (P=200 and K=600 mg/kg soil). When treating with N 3 and N 4 , the application of the whole nitrogen rate was compared with its split application. It was found that the form of the nitrogen fertilizer played no important role for the formation of the yield of biomass and the uptake of nitrogen with the yield when it is applied in low nitrogen rates and maize was grown on calcareous black earth. The yield of biomass and the uptake of nitrogen with the yield of maize reach their maximum under the conditions of calcareous black earth and high nitrogen rates applied as urea depressed the plants which proves the statement that in case of calcareous black earth application of ammonium sulfate should be preferred rather that urea, fertilization with which should be avoided. No depression of plants was observed under the conditions of leached black earth and application of high urea rates. The amount of nitrogen taken up is growing with the increasing of the nitrogen rate (excluding the N-treatment). The split application of high nitrogen rates increased notably the yield of maize-vegetation mass which proved the great ability of this crop for effective utilization of the nitrogen fertilizers when applied in portions and at suitable phases of plant vegetation. The role of the fertilizer nitrogen on the formation of the plant mass yield is much greater compared to that of the soil nitrogen; in the split application of urea the soil nitrogen plays a much bigger role than in its single application. The additional mobilization of the soil nitrogen under the influence of the applied nitrogen

  3. Using 15N in studies on the uptake of mineral and organic nitrogen by plants

    International Nuclear Information System (INIS)

    Mitovska, R.

    1983-01-01

    Modelled microplot field experiments at the Central Experimental Station of the All-Union Institute of Fertilizers and Agrochemistry in Moscow were used to study the uptake of nitrogen ( 15 N) applied together or individually with minerals or with green oats mass or in both ways. The studies were conducted on soddy podzolic, heavy loam, soddy podzolic sandy soil and leached chernozem. It was established that the soddy podzolic heavy loam had the highest natural fertility and showed greatest response to the applied N

  4. Using /sup 15/N in studies on the uptake of mineral and organic nitrogen by plants

    Energy Technology Data Exchange (ETDEWEB)

    Mitovska, R. (Akademiya na Selskostopanskite Nauki, Sofia (Bulgaria). Inst. po Pochvoznanie)

    1983-01-01

    Modelled microplot field experiments at the Central Experimental Station of the All-Union Institute of Fertilizers and Agrochemistry in Moscow were used to study the uptake of nitrogen (/sup 15/N) applied together or individually with minerals or with green oats mass or in both ways. The studies were conducted on soddy podzolic, heavy loam, soddy podzolic sandy soil and leached chernozem. It was established that the soddy podzolic heavy loam had the highest natural fertility and showed greatest response to the applied N.

  5. Influence of soil moisture on uptake and utilization of applied nitrogen in tea

    International Nuclear Information System (INIS)

    Marimuthu, S.; Raj Kumar, R.

    1999-01-01

    An experiment was conducted with pot-grown young tea plants to study N uptake under different soil moisture regime. Labelled urea nitrogen was found effectively utilized under rainfed conditions. However, N loss through percolation/leaching in response to saturated moisture was as high as 33.3%. Plants grown under controlled conditions utilized less amount of applied N and the rest was retained in the soil. Unaccounted loss, in both the cases, was approximately 9%. Fertilizer-use efficiency of young tea plants under rain fed conditions was about 35% while it was 15% under moisture deficient conditions. Results on N balance in tea soils are discussed. (author)

  6. Arbuscular mycorrhiza improve growth, nitrogen uptake, and nitrogen use efficiency in wheat grown under elevated CO2.

    Science.gov (United States)

    Zhu, Xiancan; Song, Fengbin; Liu, Shengqun; Liu, Fulai

    2016-02-01

    Effects of the arbuscular mycorrhizal (AM) fungus Rhizophagus irregularis on plant growth, carbon (C) and nitrogen (N) accumulation, and partitioning was investigated in Triticum aestivum L. plants grown under elevated CO2 in a pot experiment. Wheat plants inoculated or not inoculated with the AM fungus were grown in two glasshouse cells with different CO2 concentrations (400 and 700 ppm) for 10 weeks. A (15)N isotope labeling technique was used to trace plant N uptake. Results showed that elevated CO2 increased AM fungal colonization. Under CO2 elevation, AM plants had higher C concentration and higher plant biomass than the non-AM plants. CO2 elevation did not affect C and N partitioning in plant organs, while AM symbiosis increased C and N allocation into the roots. In addition, plant C and N accumulation, (15)N recovery rate, and N use efficiency (NUE) were significantly higher in AM plants than in non-AM controls under CO2 enrichment. It is concluded that AM symbiosis favors C and N partitioning in roots, increases C accumulation and N uptake, and leads to greater NUE in wheat plants grown at elevated CO2.

  7. Relative importance of plant uptake and plant associated denitrification for removal of nitrogen from mine drainage in sub-arctic wetlands.

    Science.gov (United States)

    Hallin, Sara; Hellman, Maria; Choudhury, Maidul I; Ecke, Frauke

    2015-11-15

    Reactive nitrogen (N) species released from undetonated ammonium-nitrate based explosives used in mining or other blasting operations are an emerging environmental problem. Wetlands are frequently used to treat N-contaminated water in temperate climate, but knowledge on plant-microbial interactions and treatment potential in sub-arctic wetlands is limited. Here, we compare the relative importance of plant uptake and denitrification among five plant species commonly occurring in sub-arctic wetlands for removal of N in nitrate-rich mine drainage in northern Sweden. Nitrogen uptake and plant associated potential denitrification activity and genetic potential for denitrification based on quantitative PCR of the denitrification genes nirS, nirK, nosZI and nosZII were determined in plants growing both in situ and cultivated in a growth chamber. The growth chamber and in situ studies generated similar results, suggesting high relevance and applicability of results from growth chamber experiments. We identified denitrification as the dominating pathway for N-removal and abundances of denitrification genes were strong indicators of plant associated denitrification activity. The magnitude and direction of the effect differed among the plant species, with the aquatic moss Drepanocladus fluitans showing exceptionally high ratios between denitrification and uptake rates, compared to the other species. However, to acquire realistic estimates of N-removal potential of specific wetlands and their associated plant species, the total plant biomass needs to be considered. The species-specific plant N-uptake and abundance of denitrification genes on the root or plant surfaces were affected by the presence of other plant species, which show that both multi- and inter-trophic interactions are occurring. Future studies on N-removal potential of wetland plant species should consider how to best exploit these interactions in sub-arctic wetlands. Copyright © 2015 Elsevier Ltd. All rights

  8. Radiation utilization efficiency, nitrogen uptake and modeling crop growth and yield of rainfed rice under different nitrogen rates

    International Nuclear Information System (INIS)

    Gouranga, Kar; Ashwani Kumar; Mohapatra, Sucharita

    2014-01-01

    Optimum utilization of photosynthetically active radiation (PAR) along with proper nitrogen (N) management for sustainable rice production is still a promising management recommendation for sustainable rainfed rice cultivation in eastern India. The objective of this investigation was to study radiation utilization efficiency (RUE), N uptake and modeling growth and productivity of wet/rainy season rice (cv. Lalat and Gayatri) under 0, 50, 90, 120 and 150 kg ha -1 N application. Results showed that N rates significantly affected plant biomass, leaf area index (LAI), biological yield (straw and grain yield) and N uptake for both the varieties. The intercepted photosynthetically active radiation (IPAR) and spectral reflectance based vegetation indices (IR/R, NDVI) were also different between two varieties and among N rates. Higher rate of N increased the RUE significantly; averaged over years and varieties, mean values of RUE were 1.35, 1.70, 2.01, 2.15 and 2.17 g MJ -1 under 0, 50, 90, 120 and 150 kg N ha -1 , respectively. Though crop growth, yield, N uptake and RUE were higher at 150 kg N ha -1 but the results were at par with 120 kg N ha -1 . Agronomic N use efficiency (ANUE) was also low at 150 kg N ha -1 . The DSSAT v 4.5 model was applied to simulate crop growth, yield and phenology of the crop under different N rates. Model performance was found to be poor at low N rates (0, 50 kg N ha -1 ), but the model performed fairly well at higher N rates (90 kg ha -1 and above). (author)

  9. Boreal bog plants: nitrogen sources and uptake of recently deposited nitrogen

    International Nuclear Information System (INIS)

    Nordbakken, J.F.; Ohlson, M.; Hoegberg, P.

    2003-01-01

    The main goals of this study were to determine the δ 15 N signature of quantitatively important boreal bog plants as basis for discussing their N sources, and to assess the effects of five different 3 year N treatments (i.e. 0, 5, 10, 20 and 40 kg N ha -1 year -1 ) on the bog plants and surface peat at different depths (i.e. 0, 5, 10, 20 and 40 cm) by using 15 N as tracer. Plants and peat were analyzed for N concentration, 15 N natural abundance and 15 N at.%. From the results we draw three main conclusions: First, the relative importance of different N sources is species-specific among bog plants. Second, an annual addition of 5 kg N ha -1 year -1 was sufficient to significantly increase the N concentration in Sphagnum mosses, liverworts and shallow rooted vascular plants, and an annual addition of 40 kg N ha -1 year -1 during 3 years was not sufficient to increase the N concentration in deep rooted plants, although the 15 N content increased continuously, indicating a possible longer term effect. Third, an annual addition of 40 kg N ha -1 year -1 during 3 years increased the N content in surface peat at depths of 5 and 10 cm, but not at depths of 20 and 40 cm, indicating the capacity of the living Sphagnum mosses and the surface peat to take up deposited N, and thereby function as a filter. - Living Sphagnum mosses and surface peat function as a filter for added nitrogen

  10. Effect of soil-moisture stress on nitrogen uptake and fixation by plants

    International Nuclear Information System (INIS)

    Mitrosuhardjo, M.M.

    1983-01-01

    The effect of four levels of soil moisture, namely 25, 30, 35, and 40% (g/g) on nitrogen uptake and fixation by plants was studied in a greenhouse experiment. Soybean and wheat were used in this experiment. Both crops were grown in pots containing 7 kg loamy alluvial soil. Rhizobium japonicum was used as an inoculant for soybean, one week after planting. Nitrogen-15 labelled urea with 10% atom excess was applied to each pot with a dose rate of 70 mg N/pot (20 kg N/ha) two weeks after planting. Soil moisture was regularly controlled with porous-cup mercury tensiometers, and the amount of water consumed by plants was always recorded. Water was applied to each pot with a distribution pipe which was laid down in the centre of the soil depth, horizontally in a circular form, and was connected with a smaller pipe to the soil surface. The result obtained showed that the amount of water consumed by plants grown in a higher level of soil moisture was increased until soil aeration problems arose. A different amount of water consumption between soybean and wheat was observed at least until a certain period of growing time. Fertilizer nitrogen taken up by both crops varied with the different levels of soil moisture. Generally, greater fertilizer nitrogen was taken up by both crops grown in a higher level of soil moisture. The symbiotic fixation of nitrogen was reasonable, although no clarification has been found about the role of the four levels of soil-moisture treatment on it. A similar effect of soil-moisture stress on nodule dry matter and acetylene reduction was found. (author)

  11. In situ EELS and TEM observation of Al implanted with nitrogen ions

    International Nuclear Information System (INIS)

    Hojou, K.; Furuno, S.; Kushita, K.N.; Otsu, H.; Izui, K.

    1995-01-01

    Formation processes of Aluminum nitride (AIN) in Aluminum (AI) implanted with nitrogen were examined by in situ EELS and TEM observations during nitrogen ion implantation in an electron microscope at room temperature and 400 deg C. AIN phase was identified both by EDP and EELS after nitrogen ion implantation to 6 x 10 20 (N + )/m 2 . The observed peak (20.8 eV) in EELS spectra was identified as plasmon loss peak of AIN formed in AI. The binding energy of N ls in AI was found to shift by about 4 eV to the lower side with increasing nitrogen-ion fluence. Unreacted AI was also found to remain in the AIN films after high fluence implantation both at room temperature and 400 deg C. (authors). 11 refs., 5 figs., 2 tabs

  12. Comparison of nitrate accumulation, nitrogen uptake and utilization efficiency among different spinach (Spinacia oleracea L. genotypes

    Directory of Open Access Journals (Sweden)

    Zhou Jianjian

    2017-10-01

    Full Text Available A hydroponic experiment was conducted to study the difference of nitrate accumulation,nitrogen uptake and utilization efficiency between four spinach (Spinacia oleracea L. genotypes (So10,So13,So18 and So57. Results showed that So13 had the highest nitrate contents under two nitrate (NO3--N level (0.5 mmol·L-1,15 mmol·L-1 conditions,whereas So10 had the lowest nitrate contents. So18 had the similar nitrate contents with So13 under low NO3- level,while it showed no significant difference of nitrate contents with So57 under high NO3- treatment. The 15NO3--N uptake rates of So13 were the highest one among four genotypes,while the N utilization efficiency (NutE and N utilization ratio (NUR of So13 were significantly lower than those of So18 and So57. The shoot dry mass,nitrate reductase activity,NutE,NUR of So18 and So57 were higher than those of So13 and So10,while their 15NO3--N uptake rates were lower than those of So13. The shoot dry mass,nitrate reductase activity,NutE,N utilization ratio of So10 were significantly lower than those of So18 and So57,and its 15NO3--N uptake rate was significantly lower than those of So13. Among the four spinach genotypes,the So57 can be selected as elite germplasm using for spinach production for its relatively lower nitrate content and higher N efficiency.

  13. EFFECTS OF AMELIORANT COMPOSITIONS ON NITROGEN MINERALIZATION AND UPTAKE BY SWEET CORN IN DEGRADED PEATLAND

    Directory of Open Access Journals (Sweden)

    Eni Maftu’ah

    2014-04-01

    Full Text Available Peat soil is characterized by poor nitrogen (N availability. Ameliorants are expected to rectify this problem. This research  aimed to study the effect of ameliorant on N availability and N uptake by sweet corn plant in degraded peatland. The experiment was conducted in the greenhouse in May-July 2011 and on peatland of Kalampangan Village, Palangkaraya, Central Kalimantan in September-December 2011. Burnt peat soil of Kalampangan was used in the greenhouse experiment and sweet corn was used as an indicator plant. The treatments consisted of two factors, i.e. compositions of ameliorants by weight (A1 = 80% chicken manure + 20% dolomite; A2 = 80% local farm weed + 20% dolomite; A3 = 80% mineral soil + 20% dolomite; A4 = 20% chicken manure + 20% local farm weed + 20% residue of Chinese water chestnut (Eleocharis dulcis + 20% mineral soil + 20% dolomite; and A5 = 19% chicken manure + 71.5% mineral soil + 9.5% dolomite and rates of those ameliorants (5, 10, 15, 20 and 25 t ha-1. The experiment was arranged in a completely randomized block design with three replications. Data were collected every two weeks for five times. Observations were made on soil pH, available N (NH4+, NO3-, plant height, and N uptake in root and shoot. The results showed that  treatment A1 increased soil pH and availability of NH4+ and NO3-  in peat soils at the maximum vegetative stage. Treatment A1 provided the highest N availability and N uptake by the plant. Field experiment showed that N uptake increased  with the plant yield. Optimum yield of fresh corn cob was obtained from treatment A1 at the rate of 20 t ha-1. This research reconfirms the effectiveness of chicken manure and dolomite as peat soil ameliorant.

  14. Use of bioreactor landfill for nitrogen removal to enhance methane production through ex situ simultaneous nitrification-denitrification and in situ denitrification.

    Science.gov (United States)

    Sun, Xiaojie; Zhang, Hongxia; Cheng, Zhaowen

    2017-08-01

    High concentrations of nitrate-nitrogen (NO 3 - -N) derived from ex situ nitrification phase can inhibit methane production during ex situ nitrification and in situ denitrification bioreactor landfill. A combined process comprised of ex situ simultaneous nitrification-denitrification (SND) in an aged refuse bioreactor (ARB) and in situ denitrification in a fresh refuse bioreactor (FRB) was conducted to reduce the negative effect of high concentrationsof NO 3 - -N. Ex situ SND can be achieved because NO 3 - -N concentration can be reduced and the removal rate of ammonium-nitrogen (NH 4 + -N) remains largely unchanged when the ventilation rate of ARB-A2 is controlled. The average NO 3 - -N concentrations of effluent were 470mg/L in ex situ nitrification ARB-A1 and 186mg/L in ex situ SND ARB-A2. The average NH 4 + -N removal rates of ARB-A1 and ARB-A2 were 98% and 94%, respectively. Based on the experimental data from week 4 to week 30, it is predicted that NH 4 + -N concentration in FRB-F1 of the ex situ nitrification and in situ denitrification process would reach 25mg/L after 63weeks, and about 40weeks for the FRB-F2 of ex situ SND and in situ denitrification process . Ex situ SND and in situ denitrification process can improve themethane production of FRB-F2. The lag phase time of methane production for the FRB-F2 was 11weeks. This phase was significantly shorter than the 15-week phases of FRB-F1 in ex situ nitrification and in situ denitrification process. A seven-week stabilizationphase was required to increase methane content from 5% to 50% for FRB-F2. Methane content in FRB-F1 did not reach 50% but reached the 45% peak after 20weeks. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Effects of inorganic nitrogen forms on growth, morphology, nitrogen uptake capacity and nutrient allocation of four tropical aquatic macrophytes (Salvinia cucullata, Ipomoea aquatica, Cyperus involucratus and Vetiveria zizanioides)

    DEFF Research Database (Denmark)

    Jampeetong, Arunothai; Brix, Hans; Kantawanichkul, Suwasa

    2012-01-01

    This study assesses the growth and morphological responses, nitrogen uptake and nutrient allocation in four aquatic macrophytes when supplied with different inorganic nitrogen treatments (1) NH4+, (2) NO3−, or (3) both NH4+ and NO3−. Two free-floating species (Salvinia cucullata Roxb. ex Bory...... and Ipomoea aquatica Forssk.) and two emergent species (Cyperus involucratus Rottb. and Vetiveria zizanioides (L.) Nash ex Small) were grown with these N treatments at equimolar concentrations (500 M). Overall, the plants responded well to NH4+. Growth as RGR was highest in S. cucullata (0.12±0.003 d−1......) followed by I. aquatica (0.035 ±0.002 d−1), C. involucratus (0.03±0.002 d−1) and V. zizanioides (0.02±0.003 d−1). The NH4+ uptake rate was significantly higher than the NO3− uptake rate. The free-floating species had higher nitrogen uptake rates than the emergent species. The N-uptake rate differed between...

  16. Effect of long-term drought on carbon allocation and nitrogen uptake of Pinus sylvestris seedlings

    Science.gov (United States)

    Pumpanen, Jukka; Aaltonen, Heidi; Lindén, Aki; Köster, Kajar; Biasi, Christina; Heinonsalo, Jussi

    2015-04-01

    Weather extremes such as drought events are expected to increase in the future as a result of climate change. The drought affects the allocation of carbon assimilated by plants e.g. by modifying the root to shoot ratio, amount of fine roots and the amount of mycorrhizal fungal hyphae. We studied the effect of long term drought on the allocation of carbon in a common garden experiment with 4-year-old Pinus sylvestris seedlings. Half of the seedlings were exposed to long-term drought by setting the soil water content close to wilting point for over two growing seasons whereas the other half was grown in soil close to field capacity. We conducted a pulse labelling with 13CO2 in the end of the study by injecting a known amount of 13C enriched CO2 to the seedlings and measuring the CO2 uptake and distribution of 13C to the biomass of the seedlings and to the root and rhizosphere respiration. In addition, we studied the effect of drought on the decomposition of needle litter and uptake of nitrogen by 15N labelled needles buried in the soil in litter bags. The litterbags were collected and harvested in the end of the experiment and the changes in microbial community in the litterbags were studied from the phospholipid fatty acid (PLFA) composition. We also determined the 15N isotope concentrations from the needles of the seedlings to study the effect of drought on the nitrogen uptake of the seedlings. Our results indicate that the drought had a significant effect both on the biomass allocation of the seedlings and on the microbial species composition. The amount of carbon allocated belowground was much higher in the seedlings exposed to drought compared to the control seedlings. The seedlings seemed to adapt their carbon allocation to long-term drought to sustain adequate needle biomass and water uptake. The seedlings also adapted their osmotic potential and photosynthesis capacity to sustain the long-term drought as was indicated by the measurements of osmotic potential

  17. Regulation of nitrogen uptake and assimilation: Effects of nitrogen source and root-zone and aerial environment on growth and productivity of soybean

    Science.gov (United States)

    Raper, C. David, Jr.

    1994-01-01

    The interdependence of root and shoot growth produces a functional equilibrium as described in quantitative terms by numerous authors. It was noted that bean seedlings grown in a constant environment tended to have a constant distribution pattern of dry matter between roots and leaves characteristic of the set of environmental conditions. Disturbing equilibrium resulted in a change in relative growth of roots and leaves until the original ratio was restored. To define a physiological basis for regulation of nitrogen uptake within the balance between root and shoot activities, the authors combined a partioning scheme and a utilization priority assumption in which: (1) all carbon enters the plant through photosynthesis in leaves and all nitrogen enters the plant through active uptake by roots, (2) nitrogen uptake by roots and secretion into the xylem for transport to the shoots are active processes, (3) availability of exogenous nitrogen determines concentration of soluble carbohydrates within the roots, (4) leaves are a source and a sink for carbohydrates, and (5) the requirement for nitrogen by leaf growth is proportionally greater during initiation and early expansion than during later expansion.

  18. Use of stable nitrogen isotope 15N in investigating nitrogen uptake by plants from allylisothiocyanate decomposition products

    International Nuclear Information System (INIS)

    Dolejskova, J.; Kovar, J.

    1976-01-01

    The assimilability of nitrogen from allylisothiocyanate or from its nitrogenous decomposition products by plants was investigated using 15 N-labelled allylisothiocyanate. The results show that plant nitrogen assimilation from allylisothiocyanate is the higher, the lower the total nitrogen content of the nutritive medium. (author)

  19. Nitrogen-15 Uptake by Pinus contorta Seedlings in Relation to Phenological Stage and Season

    International Nuclear Information System (INIS)

    Amponsah, Isaac G.; Lieffers, Victor J.; Comeau, Philip G.; Landhaeusser, Simon M.

    2004-01-01

    This study measured the amount of uptake of labeled nitrogen ( 15 N) of lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm) seedlings, at three different phenological stages, in a growth chamber experiment. Thirty days after 15 N application, the amount of 15 N recovered in seedlings as a percentage of the total 15 N fertilizer applied was 4% in early spring, 43% in summer and 33% in autumn. The total 15 N recovered in the plant-pot system ranged from 80 to 96%, and is higher than reported in other studies. Total 15 N recovered from the pot compartment alone ranged from 48 to 95%, suggesting that substantial pools of N remain in the soil. Results suggest that low 15 N uptake in the spring was associated with limited development of new root as a result of low spring soil temperatures. The lack of unsuberized roots in spring could be a key factor decreasing the effectiveness of early spring fertilization in the boreal forest

  20. Effect of straw application on nitrogen uptake and growth of rice

    International Nuclear Information System (INIS)

    Haryanto; Idawati.

    1990-01-01

    A pot experiment has been conducted to know the effect of straw application on the efficiency of nitrogen uptake and growth rice plant. The rice straw was applied at different time i.e. 0, 1, 2, 3 and 4 weeks before tranplanting. Soil without rice straw was used as control. Thirty gram of rice straw having 3.61 percent of N-15 atom excess was incorporated into 6 kg of latosol soil originated from Pasar jumat, in which Atomoita I, a lowland rice variety, was planted. Urea was given once at the tranplanting time. The result showed that the longer the time of the rice straw application prior to the transplanting time, the higher the N-straw uptake efficiency in the rice plant at any different stages. The highest efficiency was 6.14 percent, reached with straw applicaions at 4 weeks before tranplanting. Compared to the control, straw applications 2 weeks or more before tranplanting resulted in higher grain production, while application at or before 2 weeks of tranplanting produced lower production. (authors). 9 refs.; 5 tabs

  1. Linking phytoplankton nitrogen uptake, macronutrients and chlorophyll- a in SW Atlantic waters: The case of the Gulf of San Jorge, Argentina

    Science.gov (United States)

    Paparazzo, Flavio E.; Williams, Gabriela N.; Pisoni, Juan P.; Solís, Miriam; Esteves, José L.; Varela, Diana E.

    2017-08-01

    We compared biological and chemical parameters in surface waters of the Gulf of San Jorge to better understand carbon export and the factors that control phytoplankton production in an area of the Argentinian Continental Shelf, a vastly under sampled region of the SW Atlantic Ocean. In April of 2012, we estimated new and regenerated primary production in the Gulf by measuring nitrate and ammonium uptake, respectively. We also measured macronutrient, and in situ chlorophyll-a concentrations, which were compared to chlorophyll-a estimates from remote sensing. Although the Gulf of San Jorge presents high levels of chlorophyll-a and primary production, the relationship between these parameters is not straightforward. Previous studies showed that surface chlorophyll-a explains only part of the variance in euphotic-zone integrated primary production, and that satellite-derived chlorophyll-a underestimates in situ primary production. Our results showed large spatial variability in the Gulf, with transitional physico-chemical conditions, such as fronts, that could favor an increase in biological production. In situ chlorophyll-a concentrations were highest at the mid-shelf station (6.0 mg m- 3) and lowest at the northernmost location by an order of magnitude. Remote sensing measurements of chlorophyll-a underestimated our in situ chlorophyll-a concentrations. Total nitrogen (nitrate + ammonium) uptake showed relatively similar rates throughout the study area (≈ 130 nM-N d- 1), except in the northernmost station where it was much lower (53 nM-N d- 1). This north region had a distinct water mass and maximal levels of macronutrients (nitrate ≈ 6 μM, ammonium ≈ 1.2 μM, phosphate ≈ 1.2 μM and silicic acid ≈ 4 μM). For the entire sampling region, chlorophyll-a concentrations strongly correlated with total nitrogen uptake (r = 0.76, n = 8, p < 0.05) and new primary production (r = 0.78, n = 8, p < 0.05). Values of the f-ratio were 0.9 in mid-shelf, and ranged

  2. Valuing multiple eelgrass ecosystem services in Sweden: fish production and uptake of carbon and nitrogen

    Directory of Open Access Journals (Sweden)

    Scott Glenn Cole

    2016-01-01

    Full Text Available Valuing nature’s benefits in monetary terms is necessary for policy-makers facing trade-offs in how to spend limited financial resources on environmental protection. We provide information to assess trade-offs associated with the management of seagrass beds, which provide a number of ecosystem services, but are presently impacted by many stressors. We develop an interdisciplinary framework for valuing multiple ecosystem services and apply it to the case of eelgrass (Zostera marina, a dominant seagrass species in the northern hemisphere. We identify and quantify links between three eelgrass functions (habitat for fish, carbon and nitrogen uptake and economic goods in Sweden, quantify these using ecological endpoints, estimate the marginal average value of the impact of losing one hectare of eelgrass along the Swedish northwest coast on welfare in monetary terms, and aggregate these values while considering double-counting. Over a 20 to 50 year period we find that compared to unvegetated habitats, a hectare of eelgrass, including the organic material accumulated in the sediment, produces an additional 626 kg cod fishes and 7,535 wrasse individuals and sequesters 98.6 ton carbon and 466 kg nitrogen. We value the flow of future benefits associated with commercial fishing, avoided climate change damages, and reduced eutrophication at 170,000 SEK in 2014 (20,700 US$ or 11,000 SEK (1,300 US$ annualized at 4%. Fish production, which is the most commonly valued ecosystem service in the seagrass literature, only represented 25% of the total value whereas a conservative estimate of nitrogen regulation constituted 46%, suggesting that most seagrass beds are undervalued. Comparing these values with historic losses of eelgrass we show that the Swedish northwest coast has suffered a substantial reduction in fish production and mineral regulation. Future work should improve the understanding of the geographic scale of eelgrass functions, how local variables

  3. Nitrate transporters in leaves and their potential roles in foliar uptake of nitrogen dioxide

    Directory of Open Access Journals (Sweden)

    Yanbo eHu

    2014-07-01

    Full Text Available While plant roots are specialized organs for the uptake and transport of water and nutrients, the absorption of gaseous or liquid mineral elements by aerial plant parts has been recognized since more than one century. Nitrogen (N is an essential macronutrient which generally absorbed either as nitrate (NO3- or ammonium (NH4+ by plant roots. Gaseous nitrogen pollutants like N dioxide (NO2 can also be absorbed by plant surfaces and assimilated via the NO3– assimilation pathway. The subsequent NO3– flux may induce or repress the expression of various NO3–-responsive genes encoding for instance, the transmembrane transporters, NO3–/NO2– (nitrite reductase, or assimilatory enzymes involved in N metabolism. Based on the existing information, the aim of this review was to theoretically analyze the potential link between foliar NO2 absorption and N transport and metabolism. For such purpose, an overview of the state of knowledge on the NO3– transporter genes identified in leaves or shoots of various species and their roles for NO3– transport across the tonoplast and plasma membrane, in addition to the process of phloem loading is briefly provided. It is assumed that a NO2-induced ac-cumulation of NO3–/NO2– may alter the expression of such genes, hence linking transmembrane NO3– transporters and foliar uptake of NO2. It is likely that NRT1/NRT2 gene expression and spe-cies-dependent apoplastic buffer capacity may be also related to the species-specific foliar NO2 uptake process. It is concluded that further work focusing on the expression of NRT1 (NRT1.1, NRT1.7, NRT1.11 and NRT1.12, NRT2 (NRT2.1, NRT2.4 and NRT2.5 and chloride channel family genes (CLCa and CLCd may help us elucidate the physiological and metabolic response of plants fumigated with NO2.

  4. Effects of land-applied ammonia scrubber solutions on yield, nitrogen uptake, soil test phosphorus and phosphorus runoff

    Science.gov (United States)

    Ammonia (NH3) scrubbers reduce amounts of NH3 and dust released from animal rearing facilities, while generating nitrogen (N) rich solutions, which may be used as fertilizer. The objective of this study was to determine the effects of various NH3 scrubber solutions on yields, N uptake by forage, so...

  5. Comparative effects of partial root-zone drying and deficit irrigation on nitrogen uptake in potatoes (Solanum tuberosum L.)

    DEFF Research Database (Denmark)

    Wang, Huiqun; Liu, Fulai; Andersen, Mathias Neumann

    2009-01-01

    The effects of partial root-zone drying (PRD) as compared with deficit irrigation (DI) and full irrigation (FI) on nitrogen (N) uptake and partitioning in potato (Solanum tuberosum L.) were investigated. Potato plants were grown in split-root pots and were exposed to FI, PRD, and DI treatments...

  6. Response of Cotton to Irrigation Methods and Nitrogen Fertilization: Yield Components, Water-Use Efficiency, Nitrogen Uptake, and Recovery

    International Nuclear Information System (INIS)

    Janat, M.

    2009-01-01

    Efficient crop use of nitrogen (N) fertilizer is critical from economic and environmental viewpoints, especially under irrigated conditions. Cotton yield parameters, fiber quality, water- and N-use efficiency responses to N, and irrigation methods in northern Syria were evaluated. Field trials were conducted for two growing seasons on a Chromoxerertic Rhodoxeralf soil. Treatments consisted of drip fertigation, furrow irrigation, and five different rates of N fertilizer (50, 100, 150, 200, and 250 kg N /ha). Cotton was irrigated when soil moisture in the specified active root depth was 80% of the field capacity as indicated by the neutron probe. Seed cotton yield was higher than the national average (3,928 kg/ha) by at least 12% as compared to all treatments. Lint properties were not negatively affected by the irrigation method or N rates. Water savings under drip fertigation ranged between 25 and 50% of irrigation water relative to furrow irrigation. Crop water-use efficiencies of the drip-fertigated treatments were in most cases 100% higher than those of the corresponding furrow-irrigated treatments. The highest water demand was during the fruit-setting growth stage. It was also concluded that under drip fertigation, 100 -150 N kg/ha was adequate and comparable with the highest N rates tested under furrow irrigation regarding lint yield, N uptake, and recovery. Based on cotton seed yield and weight of stems, the overall amount of N removed from the field for the drip-fertigated treatments ranged between 101-118 kg and 116-188 N/ha for 2001 and 2002, respectively. The N removal ranged between 94-113 and 111-144 kg N/ha for the furrow-irrigated treatments for 2001 and 2002, respectively. (author)

  7. Nitrogen uptake by wheat seedlings, interactive effects of four nitrogen sources: NO3-, NO2-, NH4+, and urea

    Science.gov (United States)

    Criddle, R. S.; Ward, M. R.; Huffaker, R. C.

    1988-01-01

    The net influx (uptake) rates of NO3-, NH4+, NO2-, and urea into roots of wheat (Triticum aestivum cv Yecora Rojo) seedlings from complete nutrient solutions containing all four compounds were monitored simultaneously. Although urea uptake was too slow to monitor, its presence had major inhibitory effects on the uptake of each of the other compounds. Rates of NO3-, NH4+, and NO2- uptake depended in a complex fashion on the concentration of all four N compounds. Equations were developed which describe the uptake rates of each of the compounds, and of total N, as functions of concentrations of all N sources. Contour plots of the results show the interactions over the range of concentrations employed. The coefficients of these equations provide quantitative values for evaluating primary and interactive effects of each compound on N uptake.

  8. Growth and Nitrogen Uptake in Sorghum Plants Manured with Leucaena Leucocaphala Leaves as Affected by Nitrogen Rate and Time of Application

    International Nuclear Information System (INIS)

    Kurd Ali, F.; Al-Shammaa, M.

    2011-01-01

    A pot experiment was conducted to determine the effect of four rates of nitrogen (N) in the form of leucaena leaves and the time of application on the performance of sorghum plants using the 15 N isotopic dilution technique. Results showed that leucaena green manure (LGM) increased dry matter and N yield of sorghum. Nitrogen recoveries of LGM ranged between 23 and 47%. An additional beneficial effect of LGM was attributed to the enhancement of soil N uptake. The best timing of LGM incorporation for obtaining more N derived from LGM, less soil N uptake, and greater dry matter and N in sorghum leaves seemed to be at planting. However, the appropriate timing and rate of LGM to obtain greater dry matter and N yield in panicles, as well as in the whole plant of sorghum, appeared to be at 30 days before planting, particularly a rate of 120 kg N ha - 1. (author)

  9. Cd Toxicity and Accumulation in Rice Plants Vary with Soil Nitrogen Status and Their Genotypic Difference can be Partly Attributed to Nitrogen Uptake Capacity

    Directory of Open Access Journals (Sweden)

    Qin DU

    2009-12-01

    Full Text Available Two indica rice genotypes, viz. Milyang 46 and Zhenshan 97B differing in Cd accumulation and tolerance were used as materials in a hydroponic system consisting of four Cd levels (0, 0.1, 1.0 and 5.0 µmol/L and three N levels (23.2, 116.0 and 232.0 mg/L to study the effects of nitrogen status and nitrogen uptake capacity on Cd accumulation and tolerance in rice plants. N-efficient rice genotype, Zhenshan 97B, accumulated less Cd and showed higher Cd tolerance than N-inefficient rice genotype, Milyang 46. There was consistency between nitrogen uptake capacity and Cd tolerance in rice plants. Increase of N level in solution slightly increased Cd concentration in shoots but significantly increased in roots of both genotypes. Compared with the control at low N level, Cd tolerance in both rice genotypes could be significantly enhanced under normal N level, but no significant difference was observed between the Cd tolerances under normal N (116.0 mg/L and high N (232.0 mg/L conditions. The result proved that genotypic differences in Cd accumulation and toxicity could be, at least in part, attributed to N uptake capacity in rice plants.

  10. Uptake of Nitrogen Dioxide by Quercus robur - is There a Compensation Point?

    Science.gov (United States)

    Thielmann, A.; Chaparro, G.; Kuhn, U.; Dindorf, T.; Lehmann, L.; Kortner, M.; Tritsch, C.; Kesselmeier, J.; Meixner, F. X.

    2003-12-01

    Within the German Atmospheric-Research-Program 2000, the project ECHO (Emission and CHemical Transformation of Biogenic Volatile Organic Compounds) has been carried out in a mixed forest stand during the summer of 2002. The contribution of the Max Planck Institute for Chemistry was the complete characterization of the NOx-flux within the forest, including (a) the quantification of the biogenic NO-release from forest soils, (b) the measurement of the vertical distribution of NOx within and above the canopy and (c) the turbulent transport within and above the forest. The profile measurements allow to identify the participating processes: soil NO emission and subsequent titration of emitted NO by ozone, advection of highly polluted air masses to the site and the uptake of nitrogen dioxide within the crown area. The latter, i.e. the role of vegetation in the NOx-budget within a particular ecosystem is still a matter in controversy, which translates into considerable uncertainties in the global NOx-budget. To assess this issue, dynamic cuvette measurements were performed on a Quercus robur branch. The concurrent measurement of plant physiological (leaf temperature, stomatal conductance, transpiration and photosynthesis/respiration) and ambient parameters (radiation, ambient NOx mixing ratios) allows to put the exchange rate into context. The question whether a compensation point may be identified will especially be addressed.

  11. Indications on continued nitrogen uptake in Scots pine roots after clear-felling

    Energy Technology Data Exchange (ETDEWEB)

    Albrektson, A.; Valinger, E.; Leijon, B.; Sjoegren, H.; Sonesson, J.

    1997-11-01

    A study was performed in a 150 years old Scots pine (Pinus sylvestris L.) stand situated on a sandy moor in northern Sweden. Two plots were to be compared, and in June 1993 one was clear-felled. Even if reduced with approximately 50%, a significant fine root (diameter < 2 mm) growth was noticed at least up to one year after the clear-felling. For medium roots (diameters 2-4 and 4-6 mm) nitrogen content in root-wood and root-bark samples from the clear-felling, as compared to the reference plot, were 30-50% higher two months after the clear-felling. The difference did not increase in later comparisons. N-content in bark and wood buttress did not differ during the period studied, except for a higher percentage in bark at the clear-felling after two summers. This was believed to be a result of decomposition. The results indicate a maintained physiological activity in the stump-root system of Scots pine at least for one year at this site. An active uptake of N in roots of cut trees may influence leaching after clear-felling, the forage value of roots, and root decomposition rate and also maintain root competition with standing trees after thinning. 40 refs, 1 fig, 2 tabs

  12. Genetic variability in uptake of nitrogen at various growth stages of barley and wheat under dryland conditions

    International Nuclear Information System (INIS)

    Della, A.; Hadjichristodoulou, A.

    1976-01-01

    Protein and dry matter in a number of high protein and commercial varieties of barley and wheat were tested at various growth stages and at two locations. Large genetic variability was found in uptake of nitrogen, which was taken up generally before heading. High protein yields were not associated with high protein content but with higher dry matter yields. Nitrogen fertilization increased protein content and protein yield at a low protein location only. It was concluded that it is possible to breed for both high grain and high straw protein varieties. (author)

  13. Nitrogen uptake by Azospirillum brasilense inoculated barley (Hordeum vulgare L.) as influenced by N and P fertilization

    International Nuclear Information System (INIS)

    Negi, Mahima; Tilak, K.V.B.R.; Sachdev, M.S.

    1991-01-01

    Response of barley (Hordeum vulgare L.) in a sandy-loam soil under potted conditions revealed that application of nitrogen and phosphorus increased the population of Azospirillium in the barley rhizosphere. A two fold increase was observed in the Azospirillium population at 80 days compared to that at 40 days of plant growth. The unsterilized inoculated roots had more population than the surface sterilized inoculated roots. Increased drymatter production of barley was obtained in A. brasilense inoculated N 0 P 1 (0 kg N and 30 kg P 2 O 5 ha -1 ) treatment than uninoculated control. Also N and P uptake was higher in A. brasilense inoculated plants in the presence of both N and P fertilizers. The 15 N data revealed that at harvest nearly 36 per cent of the total N uptake was from the nitrogen fixed by A. brasilense irrespective of P treatment. (author). 16 refs., 4 tabs

  14. The Effects of Source and Rate of Nitrogen Fertilizer and Irrigation on Nitrogen Uptake of Silage Corn and Residual Soil Nitrate

    Directory of Open Access Journals (Sweden)

    M. A. Khodshenas

    2016-09-01

    Full Text Available Introduction: Growing irrigation demand for corn production, along side with draws of ground water from stressed water sources, should be limited due to scarce resources and environmental protection aspects. Nitrogen fertilizer applied at rates higher than the optimum requirement for crop production may cause an increase in nitrate accumulation below the root zone and pose a risk of nitrate leaching. Improving nitrogen management for corn production has a close relation with soil water content. In this study, we investigated the effects of source and rate of nitrogen fertilizer and irrigation on silage corn production and nitrogen concentration, nitrogen uptake and residual soil nitrate in two depths. Materials and Methods: This experiment carried out as split spli- plot in a Randomized Complete Block design (RCBD with three replications, in Arak station (Agricultural research center of markazi province, 34.12 N, 49.7 E; 1715 m above mean sea level during three years. The soil on the site was classified as a Calcaric Regosols (loamy skeletal over fragmental, carbonatic, thermic, calcixerollic xerochrepts. Main plots were irrigation treatments based on 70, 100 and 130 mm cumulative evaporation from A class Pan. Sub plots were two kinds of nitrogen fertilizers (Urea and Ammonium nitrate and sub sub-plots were five levels of nitrogen rates (0, 100, 200, 300 and 400 kgN.ha-1. Nitrogen fertilizer rates were split into three applications: 1/3 was applied at planting, 1/3 at 7-9 leaf stage and 1/3 remainder was applied before tasseling as a banding method. Phosphorus was applied at a rate of 150 kg.ha-1in each season and potassium at a rate of 30kg.ha-1 (only in first growth season based on soil testing as triple super phosphate and potassium sulfate, respectively. The corn variety of single cross 704 was planted at 20 m2 plots. The plants were sampled at dough stage from the two rows and weighted in each plot. Plant samples were dried in a forced air

  15. Growth, Carbon Isotope Discrimination and Nitrogen Uptake in Silicon and/or Potassium Fed barley Grown under Two Watering Regimes

    Directory of Open Access Journals (Sweden)

    Kurdali, Fawaz

    2013-02-01

    Full Text Available The present pot experiment was an attempt to monitor the beneficial effects of silicon (Si and/or potassium (K applications on growth and nitrogen uptake in barley plants grown under water (FC1 and non water (FC2 stress conditions using 15N and 13C isotopes. Three fertilizer rates of Si (Si50, Si100 and Si200 and one fertilizer rate of K were used. Dry matter (DM and N yield (NY in different plant parts of barley plants was affected by Si and/ or K fertilization as well as by the watering regime level under which the plants have been grown. Solely added K or in combination with adequate rate of Si (Si 100 were more effective in alleviating water stress and producing higher yield in barley plants than solely added Si. However, the latter nutrient was found to be more effective than the former in producing higher spike's N yield. Solely added Si or in combination with K significantly reduced leaves ∆13 C reflecting their bifacial effects on water use efficiency (WUE, particularly in plants grown under well watering regime. This result indicated that Si might be involved in saving water loss through reducing transpiration rate and facilitating water uptake; consequently, increasing WUE. Although the rising of soil humidity generally increased fertilizer nitrogen uptake (Ndff and its use efficiency (%NUE in barley plants, applications of K or Si fertilizers to water stressed plants resulted in significant increments of these parameters as compared with the control. Our results highlight that Si or K is not only involved in amelioration of growth of barley plants, but can also improve nitrogen uptake and fertilizer nitrogen use efficiency particularly under water deficit conditions.

  16. Nitrogen uptake by heterotrophic bacteria and phytoplankton in the nitrate-rich Thames estuary

    NARCIS (Netherlands)

    Middelburg, J.J.; Nieuwenhuize, J.

    2000-01-01

    The uptake of ammonium, nitrate, amino acids and urea was examined in the nitrate-rich Thames estuary and adjacent area in the North Sea during February 1999. The majority of uptake was by heterotrophic bacteria, as demonstrated by addition of a prokaryotic inhibitor that lowered uptake rates by 82,

  17. Fertilizer residence time affects nitrogen uptake efficiency and growth of sweet corn

    NARCIS (Netherlands)

    Zotarelli, L.; Scholberg, J.M.S.; Dukes, M.D.; Munoz-Carpena, R.

    2008-01-01

    Understanding plant N uptake dynamics is critical for increasing fertilizer N uptake efficiency (FUE) and minimize the risk of N leaching. The objective of this research was to determine the effect of residence time of N fertilizer on N uptake and FUE of sweet corn. Plants were grown in 25 L columns

  18. Coral uptake of inorganic phosphorus and nitrogen negatively affected by simultaneous changes in temperature and pH.

    Directory of Open Access Journals (Sweden)

    Claire Godinot

    Full Text Available The effects of ocean acidification and elevated seawater temperature on coral calcification and photosynthesis have been extensively investigated over the last two decades, whereas they are still unknown on nutrient uptake, despite their importance for coral energetics. We therefore studied the separate and combined impacts of increases in temperature and pCO(2 on phosphate, ammonium, and nitrate uptake rates by the scleractinian coral S. pistillata. Three experiments were performed, during 10 days i at three pH(T conditions (8.1, 7.8, and 7.5 and normal temperature (26°C, ii at three temperature conditions (26°, 29°C, and 33°C and normal pH(T (8.1, and iii at three pH(T conditions (8.1, 7.8, and 7.5 and elevated temperature (33°C. After 10 days of incubation, corals had not bleached, as protein, chlorophyll, and zooxanthellae contents were the same in all treatments. However, photosynthetic rates significantly decreased at 33°C, and were further reduced for the pH(T 7.5. The photosynthetic efficiency of PSII was only decreased by elevated temperature. Nutrient uptake rates were not affected by a change in pH alone. Conversely, elevated temperature (33°C alone induced an increase in phosphate uptake but a severe decrease in nitrate and ammonium uptake rates, even leading to a release of nitrogen into seawater. Combination of high temperature (33°C and low pH(T (7.5 resulted in a significant decrease in phosphate and nitrate uptake rates compared to control corals (26°C, pH(T = 8.1. These results indicate that both inorganic nitrogen and phosphorus metabolism may be negatively affected by the cumulative effects of ocean warming and acidification.

  19. Coral Uptake of Inorganic Phosphorus and Nitrogen Negatively Affected by Simultaneous Changes in Temperature and pH

    Science.gov (United States)

    Godinot, Claire; Houlbrèque, Fanny

    2011-01-01

    The effects of ocean acidification and elevated seawater temperature on coral calcification and photosynthesis have been extensively investigated over the last two decades, whereas they are still unknown on nutrient uptake, despite their importance for coral energetics. We therefore studied the separate and combined impacts of increases in temperature and pCO2 on phosphate, ammonium, and nitrate uptake rates by the scleractinian coral S. pistillata. Three experiments were performed, during 10 days i) at three pHT conditions (8.1, 7.8, and 7.5) and normal temperature (26°C), ii) at three temperature conditions (26°, 29°C, and 33°C) and normal pHT (8.1), and iii) at three pHT conditions (8.1, 7.8, and 7.5) and elevated temperature (33°C). After 10 days of incubation, corals had not bleached, as protein, chlorophyll, and zooxanthellae contents were the same in all treatments. However, photosynthetic rates significantly decreased at 33°C, and were further reduced for the pHT 7.5. The photosynthetic efficiency of PSII was only decreased by elevated temperature. Nutrient uptake rates were not affected by a change in pH alone. Conversely, elevated temperature (33°C) alone induced an increase in phosphate uptake but a severe decrease in nitrate and ammonium uptake rates, even leading to a release of nitrogen into seawater. Combination of high temperature (33°C) and low pHT (7.5) resulted in a significant decrease in phosphate and nitrate uptake rates compared to control corals (26°C, pHT = 8.1). These results indicate that both inorganic nitrogen and phosphorus metabolism may be negatively affected by the cumulative effects of ocean warming and acidification. PMID:21949839

  20. Identification of groundwater microorganisms capable of assimilating RDX-derived nitrogen during in-situ bioremediation

    International Nuclear Information System (INIS)

    Cho, Kun-Ching; Fuller, Mark E.; Hatzinger, Paul B.; Chu, Kung-Hui

    2016-01-01

    Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), a nitroamine explosive, is commonly detected in groundwater at military testing and training sites. The objective of this study was to characterize the microbial community capable of using nitrogen derived from the RDX or RDX intermediates during in situ bioremediation. Active groundwater microorganisms capable of utilizing nitro-, ring- or fully-labeled "1"5N-RDX as a nitrogen source were identified using stable isotope probing (SIP) in groundwater microcosms prepared from two wells in an aquifer previously amended with cheese whey to promote RDX biodegradation. A total of fifteen 16S rRNA gene sequences, clustered in Clostridia, β-Proteobacteria, and Spirochaetes, were derived from the "1"5N-labeled DNA fractions, suggesting the presence of metabolically active bacteria capable of using RDX and/or RDX intermediates as a nitrogen source. None of the derived sequences matched RDX-degrading cultures commonly studied in the laboratory, but some of these genera have previously been linked to RDX degradation in site groundwater via "1"3C-SIP. When additional cheese whey was added to the groundwater samples, 28 sequences grouped into Bacteroidia, Bacilli, and α-, β-, and γ-Proteobacteria were identified. The data suggest that numerous bacteria are capable of incorporating N from ring- and nitro-groups in RDX during anaerobic bioremediation, and that some genera may be involved in both C and N incorporation from RDX. - Highlights: • Cheese whey addition resulted in 28 different clones associated with RDX degradation. • The 28 clones belong to Bacteroidia, Bacilli, and α-, β-, and γ-Proteobacteria. • SIP identified 15 clones using RDX and/or its metabolites as a nitrogen source. • The clones clustered in Clostridia, β-Proteobacteria, and Spirochaetes

  1. Identification of groundwater microorganisms capable of assimilating RDX-derived nitrogen during in-situ bioremediation

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Kun-Ching [Zachry Department of Civil Engineering, Texas A& M University, College Station, TX 77843-3136 (United States); Fuller, Mark E.; Hatzinger, Paul B. [CB& I Federal Services, Lawrenceville, NJ 08648 (United States); Chu, Kung-Hui, E-mail: kchu@civil.tamu.edu [Zachry Department of Civil Engineering, Texas A& M University, College Station, TX 77843-3136 (United States)

    2016-11-01

    Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), a nitroamine explosive, is commonly detected in groundwater at military testing and training sites. The objective of this study was to characterize the microbial community capable of using nitrogen derived from the RDX or RDX intermediates during in situ bioremediation. Active groundwater microorganisms capable of utilizing nitro-, ring- or fully-labeled {sup 15}N-RDX as a nitrogen source were identified using stable isotope probing (SIP) in groundwater microcosms prepared from two wells in an aquifer previously amended with cheese whey to promote RDX biodegradation. A total of fifteen 16S rRNA gene sequences, clustered in Clostridia, β-Proteobacteria, and Spirochaetes, were derived from the {sup 15}N-labeled DNA fractions, suggesting the presence of metabolically active bacteria capable of using RDX and/or RDX intermediates as a nitrogen source. None of the derived sequences matched RDX-degrading cultures commonly studied in the laboratory, but some of these genera have previously been linked to RDX degradation in site groundwater via {sup 13}C-SIP. When additional cheese whey was added to the groundwater samples, 28 sequences grouped into Bacteroidia, Bacilli, and α-, β-, and γ-Proteobacteria were identified. The data suggest that numerous bacteria are capable of incorporating N from ring- and nitro-groups in RDX during anaerobic bioremediation, and that some genera may be involved in both C and N incorporation from RDX. - Highlights: • Cheese whey addition resulted in 28 different clones associated with RDX degradation. • The 28 clones belong to Bacteroidia, Bacilli, and α-, β-, and γ-Proteobacteria. • SIP identified 15 clones using RDX and/or its metabolites as a nitrogen source. • The clones clustered in Clostridia, β-Proteobacteria, and Spirochaetes.

  2. Soil Microbial Communities and Gas Dynamics Contribute to Arbuscular Mycorrhizal Nitrogen Uptake and Transfer to Plants

    Science.gov (United States)

    Hestrin, R.; Harrison, M. J.; Lehmann, J.

    2016-12-01

    Arbuscular mycorrhizal fungi (AMF) associate with most terrestrial plants and influence ecosystem ecology and biogeochemistry. There is evidence that AMF play a role in soil nitrogen cycling, in part by taking up nitrogen and transferring it to plants. However, many aspects of this process are poorly understood, including the factors that control fungal access to nitrogen stored in soil organic matter. In this study, we used stable isotopes and root exclusion to track nitrogen movement from organic matter into AMF and host plants. AMF significantly increased total plant biomass and nitrogen content, but both AMF and other soil microbes seemed to compete with plants for nitrogen. Surprisingly, gaseous nitrogen species also contributed significantly to plant nitrogen content under alkaline soil conditions. Our current experiments investigate whether free-living microbial communities that have evolved under a soil nitrogen gradient influence AMF access to soil organic nitrogen and subsequent nitrogen transfer to plants. This research links interactions between plants, mycorrhizal symbionts, and free-living microbes with terrestrial carbon and nitrogen dynamics.

  3. Contribution of Nitrogen Uptake and Retranslocation during Reproductive Growth to the Nitrogen Efficiency of Winter Oilseed-Rape Cultivars (Brassica napus L. Differing in Leaf Senescence

    Directory of Open Access Journals (Sweden)

    Fabian Koeslin-Findeklee

    2016-01-01

    Full Text Available Genotypic variation in N efficiency defined as high grain yield under limited nitrogen (N supply of winter oilseed-rape line-cultivars has been predominantly attributed to N uptake efficiency (NUPT through maintained N uptake during reproductive growth related to functional stay-green. For investigating the role of stay-green, N retranslocation and N uptake during the reproductive phase for grain yield formation, two line cultivars differing in N starvation-induced leaf senescence were grown in a field experiment without mineral N (N0 and with 160 kg N·ha−1 (N160. Through frequent harvests from full flowering until maturity N uptake, N utilization and apparent N remobilization from vegetative plant parts to the pods could be calculated. NUPT proved being more important than N utilization efficiency (NUE for grain yield formation under N-limiting (N0 conditions. For cultivar differences in N efficiency, particularly N uptake during flowering (NUPT and biomass allocation efficiency (HI to the grains, were decisive. Both crop traits were related to delayed senescence of the older leaves. Remobilization of N particularly from stems and leaves was more important for pod N accumulation than N uptake after full flowering. Pod walls (high N concentrations and stems (high biomass mainly contributed to the crop-residue N at maturity. Decreasing the crop-inherent high N budget surplus of winter oilseed-rape requires increasing the low N remobilization efficiency particularly of pod-wall N to the grains. Addressing this conclusion, multi-year and -location field experiments with an extended range of cultivars including hybrids are desirable.

  4. Nitrogen nutrition of Salvinia natans: Effects of inorganic nitrogen form on growth, morphology, nitrate reductase activity and uptake kinetics of ammonium and nitrate

    DEFF Research Database (Denmark)

    Jampeetong, Arunothai; Brix, Hans

    2009-01-01

    In this study we assessed the growth, morphological responses, and N uptake kinetics of Salvinia natans when supplied with nitrogen as NO3-, NH4+, or both at equimolar concentrations (500 μM). Plants supplied with only NO3- had lower growth rates (0.17 ± 0.01 g g-1 d-1), shorter roots, smaller...... leaves with less chlorophyll than plants supplied with NH4+ alone or in combination with NO3- (RGR = 0.28 ± 0.01 g g-1 d-1). Ammonium was the preferred form of N taken up. The maximal rate of NH4+ uptake (Vmax) was 6-14 times higher than the maximal uptake rate of NO3- and the minimum concentration...... for uptake (Cmin) was lower for NH4+ than for NO3-. Plants supplied with NO3- had elevated nitrate reductase activity (NRA) particularly in the roots showing that NO3- was primarily reduced in the roots, but NRA levels were generally low (NH4...

  5. Thermal expansion and phase transformations of nitrogen-expanded austenite studied with in situ synchrotron X-ray diffraction

    DEFF Research Database (Denmark)

    Brink, Bastian; Ståhl, Kenny; Christiansen, Thomas Lundin

    2014-01-01

    Nitrogen-expanded austenite, _N, with high and low nitrogen contents was produced from AISI 316 grade stainless steel powder by gaseous nitriding in ammonia/hydrogen gas mixtures. In situ synchrotron X-ray diffraction was applied to investigate the thermal expansion and thermal stability...... as a fitting parameter. The stacking fault density is constant for temperatures up to 680 K, whereafter it decreases to nil. Surprisingly, a transition phase with composition M4N (M = Fe, Cr, Ni, Mo) appears for temperatures above 770 K. The linear coefficient of thermal expansion depends on the nitrogen...

  6. Characterization of Nitrogen Uptake Pattern in Malaysian Rice MR219 at Different Growth Stages Using 15N Isotope

    Directory of Open Access Journals (Sweden)

    Mohammad Mu’az Hashim

    2015-09-01

    Full Text Available Nitrogen (N use efficiency is usually less than 50%, and it remains a major problem in rice cultivation. Controlled release fertilizer (CRF technology is one of the well-known efforts to overcome this problem. The efficiency of CRF, however, is very much dependent on the timing of nutrient release. This study was conducted to determine the precise time of N uptake by rice as a guideline to develop efficient CRF. Fertilizer N uptake by rice at different growth stages was investigated by using 15N isotopic technique. Rice was planted in pots, with 15N urea as N source at the rate of 120 kg/hm2. Potassium and phosphorus were applied at the same rate of 50 kg/hm2. Standard agronomic practices were employed throughout the growing periods. Rice plants were harvested every two weeks until maturation at the 14th week and analyzed for total N and 15N content. Nitrogen derived from fertilizer was calculated. Total N uptake in plants consistently increased until the 11th week. After that, it started to plateau and finally declined. Moreover, N utilization by rice plants peaked at 50%, which occurred during the 11th week after transplanting. N derived from fertilizer in rice plants were in the range of 18.7% to 40.0% in all plant tissues. The remaining N was derived from soil. Based on this study, N release from CRF should complete by the 11th week after planting to ensure the maximum fertilizer N uptake by rice plants. Efficient CRF should contribute to higher N derived from fertilizer which also resultedin a higher total N uptake by rice plants, increasing the potential of rice to produce higher yield while at the same time of reducing loss.

  7. Nitrogen and phosphorus uptake in two Idaho (USA) headwater wilderness streams.

    Science.gov (United States)

    Davis, Jeffrey C; Minshall, G Wayne

    1999-05-01

    Nitrate and phosphate solutions were released into two reaches of two central Idaho streams to determine within- and between-stream variability in uptake lengths, uptake rates, and mass transfer coefficients. Physical and biotic stream characteristics and periphyton nitrate-uptake rates in recirculating chambers were measured to determine their influence on nutrient dynamics. Phosphate uptake length did not differ among the four reaches. There were no within-stream differences in nitrate uptake lengths but they did differ between the two streams. Long nitrate uptake lengths likely were due to instream concentrations above saturation but also may have been influenced by differences in active surface area and algal abundance. Nitrate and phosphate uptake lengths were longer, and uptake rates higher, than most other published values. However, mass transfer coefficients were comparable to measurements in other streams. Mass transfer coefficients may be a better parameter for temporal and spatial comparisons of instream nutrient dynamics, and for determining the underlying causes of variability in uptake length.

  8. INTERACTIONS BETWEEN SOIL TEMPERATURE AND PLANT GROWTH STAGE ON NITROGEN UPTAKE AND AMINO ACID CONTENT OF APPLE NURSERY STOCK DURING EARLY SPRING GROWTH

    Science.gov (United States)

    In the spring, nitrogen (N) uptake by apple roots is known to be delayed about three weeks after bud break. We used one-year-old 'Fuji' (Malus domestica Borkh) on M26 bare-root apple trees to determine whether timing of N uptake in the spring is dependant solely on the growth st...

  9. Metatranscriptomics reveal differences in in situ energy and nitrogen metabolism among hydrothermal vent snail symbionts.

    Science.gov (United States)

    Sanders, J G; Beinart, R A; Stewart, F J; Delong, E F; Girguis, P R

    2013-08-01

    Despite the ubiquity of chemoautotrophic symbioses at hydrothermal vents, our understanding of the influence of environmental chemistry on symbiont metabolism is limited. Transcriptomic analyses are useful for linking physiological poise to environmental conditions, but recovering samples from the deep sea is challenging, as the long recovery times can change expression profiles before preservation. Here, we present a novel, in situ RNA sampling and preservation device, which we used to compare the symbiont metatranscriptomes associated with Alviniconcha, a genus of vent snail, in which specific host-symbiont combinations are predictably distributed across a regional geochemical gradient. Metatranscriptomes of these symbionts reveal key differences in energy and nitrogen metabolism relating to both environmental chemistry (that is, the relative expression of genes) and symbiont phylogeny (that is, the specific pathways employed). Unexpectedly, dramatic differences in expression of transposases and flagellar genes suggest that different symbiont types may also have distinct life histories. These data further our understanding of these symbionts' metabolic capabilities and their expression in situ, and suggest an important role for symbionts in mediating their hosts' interaction with regional-scale differences in geochemistry.

  10. The role of nitrogen uptake on the competition ability of three vineyard Saccharomyces cerevisiae strains.

    Science.gov (United States)

    Vendramini, Chiara; Beltran, Gemma; Nadai, Chiara; Giacomini, Alessio; Mas, Albert; Corich, Viviana

    2017-10-03

    Three vineyard strains of Saccharomyces cerevisiae, P301.4, P304.4 and P254.12, were assayed in comparison with a commercial industrial strain, QA23. The aim was to understand if nitrogen availability could influence strain competition ability during must fermentation. Pairwise-strain fermentations and co-fermentations with the simultaneous presence of the four strains were performed in synthetic musts at two nitrogen levels: control nitrogen condition (CNC) that assured the suitable assimilable nitrogen amount required by the yeast strains to complete the fermentation and low nitrogen condition (LNC) where nitrogen is present at very low level. Results suggested a strong involvement of nitrogen availability, as the frequency in must of the vineyard strains, respect to QA23, in LNC was always higher than that found in CNC. Moreover, in CNC only strain P304.4 reached the same strain frequency as QA23. P304.4 competition ability increased during the fermentation, indicating better performance when nitrogen availability was dropping down. P301.4 was the only strain sensitive to QA23 killer toxin. In CNC, when it was co-inoculated with the industrial strain QA23, P301.4 was never detected. In LNC, P301.4 after 12h accounted for 10% of the total population. This percentage increased after 48h (20%). Single-strain fermentations were also run in both conditions and the nitrogen metabolism further analyzed. Fermentation kinetics, ammonium and amino-acid consumptions and the expression of genes under nitrogen catabolite repression evidenced that vineyard yeasts, and particularly strain P304.4, had higher nitrogen assimilation rate than the commercial control. In conclusion, the high nitrogen assimilation rate seems to be an additional strategy that allowed vineyard yeasts successful competition during the growth in grape musts. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Carbon: Nitrogen Interaction Regulates Expression of Genes Involved in N-Uptake and Assimilation in Brassica juncea L.

    Directory of Open Access Journals (Sweden)

    Parul Goel

    Full Text Available In plants, several cellular and metabolic pathways interact with each other to regulate processes that are vital for their growth and development. Carbon (C and Nitrogen (N are two main nutrients for plants and coordination of C and N pathways is an important factor for maintaining plant growth and development. In the present work, influence of nitrogen and sucrose (C source on growth parameters and expression of genes involved in nitrogen transport and assimilatory pathways was studied in B. juncea seedlings. For this, B. juncea seedlings were treated with four combinations of C and N source viz., N source alone (-Suc+N, C source alone (+Suc-N, with N and C source (+Suc+N or without N and C source (-Suc-N. Cotyledon size and shoot length were found to be increased in seedlings, when nitrogen alone was present in the medium. Distinct expression pattern of genes in both, root and shoot tissues was observed in response to exogenously supplied N and C. The presence or depletion of nitrogen alone in the medium leads to severe up- or down-regulation of key genes involved in N-uptake and transport (BjNRT1.1, BjNRT1.8 in root tissue and genes involved in nitrate reduction (BjNR1 and BjNR2 in shoot tissue. Moreover, expression of several genes, like BjAMT1.2, BjAMT2 and BjPK in root and two genes BjAMT2 and BjGS1.1 in shoot were found to be regulated only when C source was present in the medium. Majority of genes were found to respond in root and shoot tissues, when both C and N source were present in the medium, thus reflecting their importance as a signal in regulating expression of genes involved in N-uptake and assimilation. The present work provides insight into the regulation of genes of N-uptake and assimilatory pathway in B. juncea by interaction of both carbon and nitrogen.

  12. Carbon: Nitrogen Interaction Regulates Expression of Genes Involved in N-Uptake and Assimilation in Brassica juncea L.

    Science.gov (United States)

    Goel, Parul; Bhuria, Monika; Kaushal, Mamta

    2016-01-01

    In plants, several cellular and metabolic pathways interact with each other to regulate processes that are vital for their growth and development. Carbon (C) and Nitrogen (N) are two main nutrients for plants and coordination of C and N pathways is an important factor for maintaining plant growth and development. In the present work, influence of nitrogen and sucrose (C source) on growth parameters and expression of genes involved in nitrogen transport and assimilatory pathways was studied in B. juncea seedlings. For this, B. juncea seedlings were treated with four combinations of C and N source viz., N source alone (-Suc+N), C source alone (+Suc-N), with N and C source (+Suc+N) or without N and C source (-Suc-N). Cotyledon size and shoot length were found to be increased in seedlings, when nitrogen alone was present in the medium. Distinct expression pattern of genes in both, root and shoot tissues was observed in response to exogenously supplied N and C. The presence or depletion of nitrogen alone in the medium leads to severe up- or down-regulation of key genes involved in N-uptake and transport (BjNRT1.1, BjNRT1.8) in root tissue and genes involved in nitrate reduction (BjNR1 and BjNR2) in shoot tissue. Moreover, expression of several genes, like BjAMT1.2, BjAMT2 and BjPK in root and two genes BjAMT2 and BjGS1.1 in shoot were found to be regulated only when C source was present in the medium. Majority of genes were found to respond in root and shoot tissues, when both C and N source were present in the medium, thus reflecting their importance as a signal in regulating expression of genes involved in N-uptake and assimilation. The present work provides insight into the regulation of genes of N-uptake and assimilatory pathway in B. juncea by interaction of both carbon and nitrogen. PMID:27637072

  13. Sulfur X-Ray Absorption Spectroscopy of Living Mammalian Cells: An Enabling Tool for Sulfur Metabolomics. in Situ Observation of Uptake of Taurine Into MDCK Cells

    Energy Technology Data Exchange (ETDEWEB)

    Gnida, M.; Sneeden, E.Yu; Whitin, J.C.; Prince, R.C.; Pickering, I.J.; Korbas, M.; George, G.N.

    2009-06-01

    Sulfur is essential for life, with important roles in biological structure and function. However, because of a lack of suitable biophysical techniques, in situ information about sulfur biochemistry is generally difficult to obtain. Here, we present an in situ sulfur X-ray absorption spectroscopy (S-XAS) study of living cell cultures of the mammalian renal epithelial MDCK cell line. A great deal of information is retrieved from a characteristic sulfonate feature in the X-ray absorption spectrum of the cell cultures, which can be related to the amino acid taurine. We followed the time and dose dependence of uptake of taurine into MDCK cell monolayers. The corresponding uptake curves showed a typical saturation behavior with considerable levels of taurine accumulation inside the cells (as much as 40% of total cellular sulfur). We also investigated the polarity of uptake of taurine into MDCK cells, and our results confirmed that uptake in situ is predominantly a function of the basolateral cell surface.

  14. Uptake of different forms of nitrogen by hyphae of arbuscular mycorrhizal fungi

    International Nuclear Information System (INIS)

    Li Xia; Zhang Junling

    2007-01-01

    A two-compartment incorporating air-gap device and 15 N-labeling technique was used to investigate the uptake of different forms of N by arbuscular mycorrhizal fungi (AMF). Maize (Zea mays L.) was in association with Glomus mosseae, or Glomus intraradices. Solutions labeled with different forms of 15 N were supplied to the hyphae compartment 48 h before harvesting. The results showed that the uptake capability of 15 N varied with fungi species and N forms supplied. Percentage of 15 N taken up over 48 h by G. intraradices was higher than that by G. mosseae. The uptake capability of 15 N by AMF was in the order of 15 NH 4 + > 15 N-Gln> 15 N-Gly> 15 NO 3 - . 15 N uptake by AMF hyphae accounted for 0.005-0.032% of total N uptake. (authors)

  15. Nitrate signals determine the sensing of nitrogen through differential expression of genes involved in nitrogen uptake and assimilation in finger millet.

    Science.gov (United States)

    Gupta, Alok Kumar; Gaur, Vikram Singh; Gupta, Sanjay; Kumar, Anil

    2013-06-01

    In order to understand the molecular basis of high nitrogen use efficiency of finger millet, five genes (EcHNRT2, EcLNRT1, EcNADH-NR, EcGS, and EcFd-GOGAT) involved in nitrate uptake and assimilation were isolated using conserved primer approaches. Expression profiles of these five genes along with the previously isolated EcDof1 was studied under increased KNO3 concentrations (0.15 to 1,500 μM) for 2 h as well as at 1.5 μM for 24 h in the roots and shoots of 25 days old nitrogen deprived two contrasting finger millet genotypes (GE-3885 and GE-1437) differing in grain protein content (13.76 and 6.15 %, respectively). Time kinetics experiment revealed that, all the five genes except EcHNRT2 in the leaves of GE-3885 were induced within 30 min of nitrate exposure indicating that there might be a greater nitrogen deficit in leaves and therefore quick transportation of nitrate signals to the leaves. Exposing the plants to increasing nitrate concentrations for 2 h showed that in roots of GE-3885, NR was strongly induced while GS was repressed; however, the pattern was found to be reversed in leaves of GE-1437 indicating that in GE-3885, most of the nitrate might be reduced in the roots but assimilated in leaves and vice-versa. Furthermore, compared with the low-protein genotype, expression of HNRT2 was strongly induced in both roots and shoots of high-protein genotype at the least nitrate concentration supplied. This further indicates that GE-3885 is a quick sensor of nitrogen compared with the low-protein genotype. Furthermore, expression of EcDof1 was also found to overlap the expression of NR, GS, and GOGAT indicating that Dof1 probably regulates the expression of these genes under different conditions by sensing the nitrogen fluctuations around the root zone.

  16. Seasonal variations in uptake and in situ regeneration of nitrogen in mangrove waters

    Digital Repository Service at National Institute of Oceanography (India)

    Dham, V.V.; Heredia, A.M.; Wafar, S.; Wafar, M.V.M.

    coast of India were investigated. Nitrate was the major fraction of assimilable N (72%), followed by NH sub(4) sup(+) (16%), NO sub(2) sup(-) (6%), and urea (6%). Changes of nutrient concentrations followed clear seasonal cycles and were mainly regulated...

  17. Effects of biochar amendment and fertilizer sources on serrano chili pepper yield, uptake, and nitrogen fate

    Science.gov (United States)

    Efficient nitrogen (N) management strategies are a key approach in addressing the increase of food demand and environmental protection. Failing to achieve adequate nitrogen use efficiency (NUE) in agricultural systems can cause damaging outcomes including degradative water quality, increase in green...

  18. NH4+ enrichment and UV radiation interact to affect the photosynthesis and nitrogen uptake of Gracilaria lemaneiformis (Rhodophyta)

    International Nuclear Information System (INIS)

    Xu Zhiguang; Gao Kunshan

    2012-01-01

    Highlights: ► Inhibition induced by UVR is alleviated with the enrichment of ammonia. ► Phycoerythrin plays a key protective role against UVR at higher level of ammonia. ► Effect of UVR on the uptakes of nitrate and ammonia is different. - Abstract: Solar ultraviolet radiation (UVR, 280–400 nm) is known to inhibit the photosynthesis of macroalgae, whereas nitrogen availability may alter the sensitivity of the algae to UVR. Here, we show that UV-B (280–315 nm) significantly reduced the net photosynthetic rate of Gracilaria lemaneiformis. This inhibition was alleviated by enrichment with ammonia, which also caused a decrease in dark respiration. The presence of both UV-A (315–400 nm) and UV-B stimulated the accumulation of UV-absorbing compounds. However, this stimulation was not affected by enrichment with ammonia. The content of phycoerythrin (PE) was increased by the enrichment of ammonia only in the absence of UVR. Ammonia uptake and the activity of nitrate reductase were repressed by UVR. However, exposure to UVR had an insignificant effect on the rate of nitrate uptake. In conclusion, increased PE content associated with ammonia enrichment played a protective role against UVR in this alga, and UVR differentially affected the uptake of nitrate and ammonia.

  19. Potential Pasture Nitrogen Concentrations and Uptake from Autumn or Spring Applied Cow Urine and DCD under Field Conditions

    Science.gov (United States)

    Moir, Jim; Cameron, Keith; Di, Hong

    2016-01-01

    Nitrogen (N) cycling and losses in grazed grassland are strongly driven by urine N deposition by grazing ruminants. The objective of this study was to quantify pasture N concentrations, yield and N uptake following autumn and spring deposition of cow urine and the effects of fine particle suspension (FPS) dicyandiamide (DCD). A field plot study was conducted on the Lincoln University dairy farm, Canterbury, New Zealand from May 2003 to May 2005. FPS DCD was applied to grazed pasture plots at 10 kg·ha−1 in autumn and spring in addition to applied cow urine at a N loading rate of 1000 kg·N·ha−1, with non-urine control plots. Pasture N ranged between 1.9 and 4.8% with higher concentrations from urine. Results indicated that urine consistently increased N concentrations for around 220 days post deposition (mid December/early summer) at which point concentrations dropped to background levels. In urine patches, pasture yield and annual N uptake were dramatically increased on average by 51% for autumn and 28% for spring applied urine, in both years, when DCD was applied. This field experiment provides strong evidence that annual pasture N uptake is more strongly influenced by high urine N deposition than pasture N concentrations. FPS DCD has the potential to result in very high N uptake in urine patches, even when they are autumn deposited. PMID:27304974

  20. Nitrogen Uptake During Fall, Winter and Spring Differs Among Plant Functional Groups in a Subarctic Heath Ecosystem

    DEFF Research Database (Denmark)

    Larsen, Klaus Steenberg; Michelsen, Anders; Jonasson, Sven

    2012-01-01

    Nitrogen (N) is a critical resource for plant growth in tundra ecosystems, and species differences in the timing of N uptake may be an important feature regulating community composition and ecosystem productivity. We added 15N-labelled glycine to a subarctic heath tundra dominated by dwarf shrubs...... to 37 ± 7% by April indicating significant microbial N turnover prior to spring thaw. Only the evergreen dwarf shrubs showed active 15N acquisition before early May indicating that they had the highest potential of all functional groups for acquiring nutrients that became available in early spring....... The faster-growing deciduous shrubs did not resume 15N acquisition until after early May indicating that they relied more on nitrogen made available later during the spring/early summer. The graminoids and mosses had no significant increases in 15N tracer recovery or tissue 15N tracer concentrations after...

  1. Use of the Stable Nitrogen Isotope to Reveal the Source-Sink Regulation of Nitrogen Uptake and Remobilization during Grain Filling Phase in Maize.

    Directory of Open Access Journals (Sweden)

    Lan Yang

    Full Text Available Although the remobilization of vegetative nitrogen (N and post-silking N both contribute to grain N in maize (Zea mays L., their regulation by grain sink strength is poorly understood. Here we use 15N labeling to analyze the dynamic behaviors of both pre- and post-silking N in relation to source and sink manipulation in maize plants. The results showed that the remobilization of pre-silking N started immediately after silking and the remobilized pre-silking N had a greater contribution to grain N during early grain filling, with post-silking N importance increasing during the later filling stage. The amount of post-silking N uptake was largely driven by post-silking dry matter accumulation in both grain as well as vegetative organs. Prevention of pollination during silking had less effect on post-silking N uptake, as a consequence of compensatory growth of stems, husk + cob and roots. Also, leaves continuously export N even though grain sink was removed. The remobilization efficiency of N in the leaf and stem increased with increasing grain yield (hence N requirement. It is suggested that the remobilization of N in the leaf is controlled by sink strength but not the leaf per se. Enhancing post-silking N uptake rather than N remobilization is more likely to increase grain N accumulation.

  2. Growth, Carbon Isotope Discrimination and Nitrogen Uptake in Silicon and/or Potassium Fed barley Grown under Two Watering Regimes

    OpenAIRE

    Kurdali, Fawaz; Al-Chammaa, Mohammad

    2013-01-01

    The present pot experiment was an attempt to monitor the beneficial effects of silicon (Si) and/or potassium (K) applications on growth and nitrogen uptake in barley plants grown under water (FC1) and non water (FC2) stress conditions using 15N and 13C isotopes. Three fertilizer rates of Si (Si 50, Si 100 and Si 200) and one fertilizer rate of K were used. Dry matter (DM) and N yield (NY) in different plant parts of barley plants was affected by Si and/ or K fertilization as well as by the wa...

  3. The effect of elevated cadmium content in soil on the uptake of nitrogen by plants

    Energy Technology Data Exchange (ETDEWEB)

    Ciecko, Z.; Kalembasa, S.; Wyszkowski, M.; Rolka, E. [University of Warmia & Mazury Olsztyn, Olsztyn (Poland). Dept. of Environmental Chemistry

    2004-07-01

    The aim of this study was to determine the effect of cadmium (10, 20, 30 and 40 mg Cd/kg of soil) contamination in soil with the application of different substances (compost, brown coal, lime and bentonite) on the intake of nitrogen by some plants. The correlations between the nitrogen content in the plants and the cadmium concentration in the soil, as well as the plant yield and the content of micro- and macroelements in the plants were determined. Plant species and cadmium dose determined the effects of soil contamination with cadmium on the content of nitrogen. Large doses of cadmium caused an increase in nitrogen content in the Avena sativa straw and roots and in the Zea mays roots. Soil contamination with cadmium resulted in a decrease of nitrogen content in the Avena sativa grain, in above-ground parts and roots of the Lupinus luteus, in the above-ground parts of the Zea mays and in the above-ground parts and roots of Phacelia tanacaetifolia. Among the experimental different substances, the application of bentonite had the strongest and a usually negative effect on the nitrogen content in plants. The greatest effect of bentonite was on Avena sativa grain, above-ground parts Zea mays and Lupinus luteus and Phacelia tanacaetifolia. The content of nitrogen in the plants was generally positively correlated with the content of the macroelements and some of the microelements, regardless of the substances added to the soil.

  4. Cyclic variations in nitrogen uptake rate of soybean plants: effects of external nitrate concentration

    Science.gov (United States)

    Tolley-Henry, L.; Raper, C. D. Jr; Granato, T. C.; Raper CD, J. r. (Principal Investigator)

    1988-01-01

    Net uptake of NO3- by non-nodulated soybean plants [Glycine max (L.) Merr. cv. Ransom] growing in flowing hydroponic cultures containing 0.5, 1.0 and 10.0 mol m-3 NO3- was measured daily during a 24-d period of vegetative development to determine if amplitude of maximum and minimum rates of net NO3- uptake are responsive to external concentrations of NO3-. Removal of NO3- from the replenished solutions during each 24-h period was determined by ion chromatography. Neither dry matter accumulation nor the periodicity of oscillations in net uptake rate was altered by the external NO3- concentrations. The maxima of the oscillations in net uptake rate, however, increased nearly 3-fold in response to external NO3- concentrations. The maxima and minima, respectively, changed from 4.0 and 0.6 mmol NO3- per gram root dry weight per day at an external solution level of 0.5 mol m-3 NO3- to 15.2 and -2.7 mmol NO3- per gram root dry weight per day at an external solution level of 10.0 mol m-3 NO3-. The negative values for minimum net uptake rate from 10.0 mol m-3 NO3- solutions show that net efflux was occurring and indicate that the magnitude of the efflux component of net uptake was responsive to external concentration of NO3-.

  5. A Case Study on Nitrogen Uptake and Denitrification in a Restored Urban Stream in Baltimore, Maryland

    Science.gov (United States)

    Restoring urban infrastructure and managing the nitrogen cycle represent emerging challenges for urban water quality. We investigated whether stormwater control measures (SCMs), a form of green infrastructure, integrated into restored and degraded urban stream networks can influe...

  6. Isotopic and non-isotopic estimations of fertilizer nitrogen uptake by wheat

    International Nuclear Information System (INIS)

    Hamid, A.; Ahmad, M.

    1990-01-01

    Recoveries of fertilizer N in wheat (MexiPak-65) grown in a field experiment were calculated by difference methods including linear regression of total nitrogen in wheat plant, nitrogen 15 method and linear regression of fertilizer. The difference method overestimated recoveries of applied fertilizer at the rates of application when compared to the nitrogen 15 method. Similarly linear regression of total N in wheat on rates of N over estimated recoveries by 25% at the three rates. The difference method of calculating the recoveries of fertilizer N in wheat could give values similar to those calculated by nitrogen 15 method when the minimal N treatment was used as a base instead of zero-N. (orig./A.B.)

  7. Nitrogen uptake by phytoplankton in surface waters of the Indian sector of Southern Ocean during austral summer

    Science.gov (United States)

    Tripathy, S. C.; Patra, Sivaji; Vishnu Vardhan, K.; Sarkar, A.; Mishra, R. K.; Anilkumar, N.

    2018-03-01

    This study reports the nitrogen uptake rate (using 15N tracer) of phytoplankton in surface waters of different frontal zones in the Indian sector of the Southern Ocean (SO) during austral summer of 2013. The investigated area encompasses four major frontal systems, i.e., the subtropical front (STF), subantarctic front (SAF), polar front-1 (PF1) and polar front-2 (PF2). Southward decrease of surface water temperature was observed, whereas surface salinity did not show any significant trend. Nutrient (NO3 - and SiO4 4-) concentrations increased southward from STF to PF; while ammonium (NH4 +), nitrite (NO2 -) and phosphate (PO4 3-) remained comparatively stable. Analysis of nutrient ratios indicated potential N-limited conditions at the STF and SAF but no such scenario was observed for PF. In terms of phytoplankton biomass, PF1 was found to be the most productive followed by SAF, whereas PF2 was the least productive region. Nitrate uptake rate increased with increasing latitude, as no systematic spatial variation was discerned for NH4 + and urea (CO(NH2)2). Linear relationship between nitrate and total N-uptake reveals that the studied area is capable of exporting up to 60% of the total production to the deep ocean if the environmental settings are favorable. Like N-uptake rates the f-ratio also increased towards PF region indicating comparatively higher new production in the PF than in the subtropics. The moderately high average f-ratio (0.53) indicates potentially near equal contributions by new production and regenerated production to the total productivity in the study area. Elevation in N-uptake rates with declining temperature suggests that the SO with its vast quantity of cool water could play an important role in drawing down the atmospheric CO2 through the "solubility pump".

  8. 4H-SiC surface energy tuning by nitrogen up-take

    Energy Technology Data Exchange (ETDEWEB)

    Pitthan, E., E-mail: eduardo.pitthan@ufrgs.br [Institute for Advanced Materials, Devices and Nanotechnology, Rutgers University, Piscataway, NJ 08854 (United States); PGMICRO, UFRGS, 91509-900, Porto Alegre, RS (Brazil); Amarasinghe, V.P. [Institute for Advanced Materials, Devices and Nanotechnology, Rutgers University, Piscataway, NJ 08854 (United States); Xu, C.; Gustafsson, T. [Institute for Advanced Materials, Devices and Nanotechnology, Rutgers University, Piscataway, NJ 08854 (United States); Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854 (United States); Stedile, F.C. [PGMICRO, UFRGS, 91509-900, Porto Alegre, RS (Brazil); Instituto de Química, UFRGS, 91509-900, Porto Alegre, RS (Brazil); Feldman, L.C. [Institute for Advanced Materials, Devices and Nanotechnology, Rutgers University, Piscataway, NJ 08854 (United States); Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854 (United States)

    2017-04-30

    Highlights: • Wettability modification of 4H-SiC as a function of nitrogen adsorption is reported. • SiC surface energy was significantly reduced as nitrogen was incorporated. • Modifications obtained were proved to be inert to etching and stable against time. • Variable control of SiC surface provides new opportunities for biomedical applications. - Abstract: Surface energy modification and surface wettability of 4H silicon carbide (0001) as a function of nitrogen adsorption is reported. The surface wettability is shown to go from primarily hydrophilic to hydrophobic and the surface energy was significantly reduced with increasing nitrogen incorporation. These changes are investigated by x-ray photoelectron spectroscopy and contact angle measurements. The surface energy was quantitatively determined by the Fowkes model and interpreted primarily in terms of the variation of the surface chemistry with nitrogen coverage. Variable control of SiC surface energies with a simple and controllable atomic additive such as nitrogen that is inert to etching, stable against time, and also effective in electrical passivation, can provide new opportunities for SiC biomedical applications, where surface wetting plays an important role in the interaction with the biological interfaces.

  9. Uptake of dissolved inorganic and organic nitrogen by the benthic toxic dinoflagellate Ostreopsis cf. ovata.

    Science.gov (United States)

    Jauzein, Cécile; Couet, Douglas; Blasco, Thierry; Lemée, Rodolphe

    2017-05-01

    Environmental factors that shape dynamics of benthic toxic blooms are largely unknown. In particular, for the toxic dinoflagellate Ostreopsis cf. ovata, the importance of the availability of nutrients and the contribution of the inorganic and organic pools to growth need to be quantified in marine coastal environments. The present study aimed at characterizing N-uptake of dissolved inorganic and organic sources by O. cf. ovata cells, using the 15 N-labelling technique. Experiments were conducted taking into account potential interactions between nutrient uptake systems as well as variations with the diel cycle. Uptake abilities of O. cf. ovata were parameterized for ammonium (NH 4 + ), nitrate (NO 3 - ) and N-urea, from the estimation of kinetic and inhibition parameters. In the range of 0 to 10μmolNL -1 , kinetic curves showed a clear preference pattern following the ranking NH 4 + >NO 3 - >N-urea, where the preferential uptake of NH 4 + relative to NO 3 - was accentuated by an inhibitory effect of NH 4 + concentration on NO 3 - uptake capabilities. Conversely, under high nutrient concentrations, the preference for NH 4 + relative to NO 3 - was largely reduced, probably because of the existence of a low-affinity high capacity inducible NO 3 - uptake system. Ability to take up nutrients in darkness could not be defined as a competitive advantage for O. cf. ovata. Species competitiveness can also be defined from nutrient uptake kinetic parameters. A strong affinity for NH 4 + was observed for O. cf. ovata cells that may partly explain the success of this toxic species during the summer season in the Bay of Villefranche-sur-mer (France). Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Precipitation reactions caused by nitrogen uptake during service at high temperatures of a niobium stabilised austenitic stainless steel

    International Nuclear Information System (INIS)

    Erneman, J.; Schwind, M.; Liu, P.; Nilsson, J.-O.; Andren, H.-O.; Aagren, J.

    2004-01-01

    Precipitation phenomena in type 347 austenitic stainless steels have been investigated after long-term heat treatment and creep in air at 700 and 800 deg. C. Nitrogen uptake was observed during long-term creep testing at 800 deg. C. No such effect was observed at 700 deg. C although times up to about 70,000 h were used. The major phases precipitated after long time exposure at 800 deg. C were primary Nb(C,N), Z-phase, Cr 2 N and M 23 C 6 , while primary Nb(C,N), secondary Nb(C,N) and σ-phase were the major phases at 700 deg. C. Z-phase precipitated in both intragranular and intergranular form at 800 deg. C. Large precipitates exhibiting a core/rim structure showed a rim of Z-phase surrounding undissolved primary Nb(C,N). The microstructural evolution during creep deformation in air at 800 deg. C was modelled thermodynamically. The model satisfactorily predicts nitrogen uptake and the essential features of the evolution of the microstructure with time. The precipitation sequence could be qualitatively described, although it was not possible to model the formation of all precipitates

  11. Grain quality and N uptake of spring cereals as affected by nitrogen fertilization in northern conditions: a meta-analysis

    Directory of Open Access Journals (Sweden)

    Elena Valkama

    2013-06-01

    Full Text Available We reviewed quantitatively 40 Finnish field experiments related to the effect of nitrogen (N fertilizer on the main parameters of grain quality and N uptake of spring cereals. The experiments were conducted on a wide range of mineral soils under varying growth conditions from the 1950s to the 1990s. Overall there was no statistically significant effect on 1000 grain weight and a slightly negative effect on grain test weight. Nitrogen fertilizer increased N uptake much more steeply in slightly acidic soils (SA, pH 5.8–6.9, located mostly in South Finland, than in moderately acidic soils (MA, pH 5.0–5.7, located in Central Finland. With increasing N rates, protein content increased to a larger extent in spring barley and oats than in spring wheat. In the light of the current trend to reduce N fertilizerapplication, the obtained regressions between N rates and the parameters of grain quality may be used to maintain yield quality at a desirable level, while optimizing N management.

  12. Interaction effect on nitrogen and sulfur on growth and nutrient uptake by maize

    International Nuclear Information System (INIS)

    Jaggi, R.C.; Aulakh, M.S.; Dev, G.

    1977-01-01

    A pot culture experiment was conducted in the greenhouse on an arid brown loamy sand deficient in both available N and S with maize (Ganga-5) as the test corp. Three levels of N (0, 30, 60 ppm) as NH 4 Cl in factorial combination with three levels of S (0, 10, 20 ppm) as Na 2 35 SO 4 were replicated thrice. Application of N upto 60 ppm S significantly increased dry matter yield and uptake of N and S by maize (stem + levels) and their combined application showed sinergistic effect for both yield and uptake of these nutrients. Maximum yield of dry matter and uptake of the nutrients were obtained with the application of 60 ppm N and 20 ppm S. The radioassay data corroborated the beneficial effect of N on the efficiency of applied S. (author)

  13. NH4+ enrichment and UV radiation interact to affect the photosynthesis and nitrogen uptake of Gracilaria lemaneiformis (Rhodophyta).

    Science.gov (United States)

    Xu, Zhiguang; Gao, Kunshan

    2012-01-01

    Solar ultraviolet radiation (UVR, 280-400 nm) is known to inhibit the photosynthesis of macroalgae, whereas nitrogen availability may alter the sensitivity of the algae to UVR. Here, we show that UV-B (280-315 nm) significantly reduced the net photosynthetic rate of Gracilaria lemaneiformis. This inhibition was alleviated by enrichment with ammonia, which also caused a decrease in dark respiration. The presence of both UV-A (315-400 nm) and UV-B stimulated the accumulation of UV-absorbing compounds. However, this stimulation was not affected by enrichment with ammonia. The content of phycoerythrin (PE) was increased by the enrichment of ammonia only in the absence of UVR. Ammonia uptake and the activity of nitrate reductase were repressed by UVR. However, exposure to UVR had an insignificant effect on the rate of nitrate uptake. In conclusion, increased PE content associated with ammonia enrichment played a protective role against UVR in this alga, and UVR differentially affected the uptake of nitrate and ammonia. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. Effects of sulfur and nitrogen on nutrients uptake of corn using ...

    African Journals Online (AJOL)

    Jane

    2011-08-08

    Aug 8, 2011 ... Sulfur uptake efficiency increases, and the deficiency symptom disappears, upon application of N fertilizer in the form of urea in S deficient soil (Murphy, 1999). Sulfur is considered one of the major essential plant nutrients and an amendment used for reclaiming alkaline and calcareous soils (Marschner ...

  15. Effects of sulfur and nitrogen on nutrients uptake of corn using ...

    African Journals Online (AJOL)

    N) fertilizer using acidified water (pH 6.5) to determine nutrients uptake and growth of maize plants grown in calcareous sandy soil. Four levels of elemental sulfur (0, 1, 5 and 10 t ha-1), two levels of N (0 and 0.34 t N ha-1) were tested at Al ...

  16. The Arabidopsis halophytic relative Thellungiella halophila tolerates nitrogen-limiting conditions by maintaining growth, nitrogen uptake, and assimilation.

    Science.gov (United States)

    Kant, Surya; Bi, Yong-Mei; Weretilnyk, Elizabeth; Barak, Simon; Rothstein, Steven J

    2008-07-01

    A comprehensive knowledge of mechanisms regulating nitrogen (N) use efficiency is required to reduce excessive input of N fertilizers while maintaining acceptable crop yields under limited N supply. Studying plant species that are naturally adapted to low N conditions could facilitate the identification of novel regulatory genes conferring better N use efficiency. Here, we show that Thellungiella halophila, a halophytic relative of Arabidopsis (Arabidopsis thaliana), grows better than Arabidopsis under moderate (1 mm nitrate) and severe (0.4 mm nitrate) N-limiting conditions. Thellungiella exhibited a lower carbon to N ratio than Arabidopsis under N limitation, which was due to Thellungiella plants possessing higher N content, total amino acids, total soluble protein, and lower starch content compared with Arabidopsis. Furthermore, Thellungiella had higher amounts of several metabolites, such as soluble sugars and organic acids, under N-sufficient conditions (4 mm nitrate). Nitrate reductase activity and NR2 gene expression in Thellungiella displayed less of a reduction in response to N limitation than in Arabidopsis. Thellungiella shoot GS1 expression was more induced by low N than in Arabidopsis, while in roots, Thellungiella GS2 expression was maintained under N limitation but was decreased in Arabidopsis. Up-regulation of NRT2.1 and NRT3.1 expression was higher and repression of NRT1.1 was lower in Thellungiella roots under N-limiting conditions compared with Arabidopsis. Differential transporter gene expression was correlated with higher nitrate influx in Thellungiella at low (15)NO(3)(-) supply. Taken together, our results suggest that Thellungiella is tolerant to N-limited conditions and could act as a model system to unravel the mechanisms for low N tolerance.

  17. Application of Response Surface Methodology for Optimization of Urea Grafted Multiwalled Carbon Nanotubes in Enhancing Nitrogen Use Efficiency and Nitrogen Uptake by Paddy Plants

    Directory of Open Access Journals (Sweden)

    Norazlina Mohamad Yatim

    2016-01-01

    Full Text Available Efficient use of urea fertilizer (UF as important nitrogen (N source in the world’s rice production has been a concern. Carbon-based materials developed to improve UF performance still represent a great challenge to be formulated for plant nutrition. Advanced N nanocarrier is developed based on functionalized multiwall carbon nanotubes (f-MWCNTs grafted with UF to produce urea-multiwall carbon nanotubes (UF-MWCNTs for enhancing the nitrogen uptake (NU and use efficiency (NUE. The grafted N can be absorbed and utilized by rice efficiently to overcome the N loss from soil-plant systems. The individual and interaction effect between the specified factors of f-MWCNTs amount (0.10–0.60 wt% and functionalization reflux time (12–24 hrs with the corresponding responses (NUE, NU were structured via the Response Surface Methodology (RSM based on five-level CCD. The UF-MWCNTs with optimized 0.5 wt% f-MWCNTs treated at 21 hrs reflux time achieve tremendous NUE up to 96% and NU at 1180 mg/pot. Significant model terms (p value < 0.05 for NUE and NU responses were confirmed by the ANOVA. Homogeneous dispersion of UF-MWCNTs was observed via FESEM and TEM. The chemical changes were monitored by FT-IR and Raman spectroscopy. Hence, this UF-MWCNTs’ approach provides a promising strategy in enhancing plant nutrition for rice.

  18. Application of Response Surface Methodology for Optimization of Urea Grafted Multi walled Carbon Nano tubes in Enhancing Nitrogen Use Efficiency and Nitrogen Uptake by Paddy Plants

    International Nuclear Information System (INIS)

    Yatim, N. M.; Shaaban, A.; Dimin, M. F.; Yusof, F.; Abo Razak, J.

    2016-01-01

    Efficient use of urea fertilizer (UF) as important nitrogen (N) source in the world’s rice production has been a concern. Carbon-based materials developed to improve UF performance still represent a great challenge to be formulated for plant nutrition. Advanced N nano carrier is developed based on functionalized multi wall carbon nano tubes (f-MWCNTs) grafted with UF to produce urea-multi wall carbon nano tubes (UF-MWCNTs) for enhancing the nitrogen uptake (NU) and use efficiency (NUE). The grafted N can be absorbed and utilized by rice efficiently to overcome the N loss from soil-plant systems. The individual and interaction effect between the specified factors of f-MWCNTs amount (0.10-0.60 wt%) and functionalization reflux time (12-24 hrs) with the corresponding responses (NUE, NU) were structured via the Response Surface Methodology (RSM) based on five-level CCD. The UF-MWCNTs with optimized 0.5 wt% f-MWCNTs treated at 21 hrs reflux time achieve tremendous NUE up to 96% and NU at 1180 mg/pot. Significant model terms (Þ value < 0.05) for NUE and NU responses were confirmed by the ANOVA. Homogeneous dispersion of UF-MWCNTs was observed via FESEM and TEM. The chemical changes were monitored by FT-IR and Raman spectroscopy. Hence, this UF-MWCNTs’ approach provides a promising strategy in enhancing plant nutrition for rice.

  19. Fertilizer nitrogen use efficiency and nutrient uptake by maize (Zea mays L.) in vertisols in Kenya

    NARCIS (Netherlands)

    Sigunga, D.O.

    1997-01-01

    The general objectives of this study were to increase the understanding of nitrogen (N) losses in maize cropping on Vertisols, and to develop management options to reduce such losses and to improve fertilizer N use efficiency. The specific objectives were. to quantify the effects of

  20. Ruminant urine increases uptake but decreases relative recovery of nitrogen by smooth brome grass

    Science.gov (United States)

    Nitrogen (N) fertilizer application and excreta return may contribute to poor nutrient recovery and use efficiencies in pastures. From 2011-2012, we investigated the effects of ruminant urine input (urine and distilled water control) and N fertilizer rate (0, 40, 80, 120, and 160 lb N/acre) on N res...

  1. Interaction of different irrigation strategies and soil textures on the nitrogen uptake of field grown potatoes

    DEFF Research Database (Denmark)

    Ahmadi, S.H.; Andersen, M.N.; Lærke, P.E.

    2011-01-01

    received 65% of FI after tuber bulking and lasted for six weeks until final harvest. Results showed that the irrigation treatments were not significantly different in terms of N uptake in the tubers, shoot, and whole crop. However, there was a statistical difference between the soil textures where plants...... in the loamy sand had the highest amount of N uptake. The interaction between irrigation treatments and soil textures was significant, and implied that under non-limiting water conditions, loamy sand is the suitable soil for potato production because plants can take up sufficient amounts of N and it could...... potentially lead to higher yield. However, under limited water conditions and applying water-saving irrigation strategies, sandy loam and coarse sand are better growth media because N is more available for the potatoes. The simple yield prediction model was developed that could explains ca. 96...

  2. Ultraviolet-B radiation effects on inorganic nitrogen uptake by natural assemblages of oceanic plankton

    International Nuclear Information System (INIS)

    Behrenfeld, M.J.; Lean, D.R.S.; Lee, H. II

    1995-01-01

    Ultraviolet-B radiation (UVBR: 290-320 nm) inhibited ammonium uptake (ρ NH4 ) and nitrate uptake (ρ NO3 ) in natural plankton assemblages collected during a transect from 37 degrees N to 55 degrees N in the Pacific Ocean. Comparison of responses in ρ NH4 to ambient solar- and lamp-enhanced UVBR spectra allowed calculation of an action spectrum for ρ NH4 inhibition. The slope of the action spectrum for ρ NH4 is half as steep as action spectra for UVBR inhibition of photosynthetic carbon uptake. Consequently, UVBR-induced photoinhibition of ρ NH4 extends to greater depths than inhibition of carbon fixation due to the greater relative effect of longer UVBR wavelengths. Inhibition of ρ NH4 was dependent upon UVBR dose when doses were weighted by the ρ NH4 action spectrum. Dependence of UVBR inhibition of ρ NH4 on dose rate was not apparent. We found that near-surface ρ NH4 and ρ NO3 can be overestimated in excess of 50% when measured using standard incubation vessels made of UVBR-absorbing materials such as polycarbonate. 68 refs., 9 figs., 1 tab

  3. Nitrogen-15 uptake by whole plants and root callus cultures of inbred maize lines and their F1 hybrids

    International Nuclear Information System (INIS)

    Mladenova, Y.; Karadimova, M.

    1981-01-01

    The uptake of nitrogen-15 by 3 maize genotypes was investigated. Comparative analysis of N15 assimilation and distribution in the organs of intact plants of two self-pollinated lines and their F1 hybrid and also in a callus tissue of roots of the same genotypes was made. From the results the conclusion is drawn that the N-use efficiency of the female line is higher than that of the male line both in intact plants and callus tissues from roots. This fact indicates that the N-use efficiency is determined not only by the functions of the cells in the shoots, suggesting the participation of the photosynthetic carboxylases but also by the functions of cells without a photosynthesizing apparatus. The N-use efficiency in the F1 hybrid manifests ''heterosis'', in spite of the intact plants or root callus tissues are being studied. (author)

  4. Uptake of pulse injected nitrogen by soil microbes and mycorrhizal and non-mycorrhizal plants in a species-diverse subarctic heath ecosystem

    DEFF Research Database (Denmark)

    Andresen, Louise Christoffersen; Jonasson, Sven; Strom, Lena

    2008-01-01

    15N labeled ammonium, glycine or glutamic acid was injected into subarctic heath soil in situ, with the purpose of investigating how the nitrogen added in these pulses was subsequently utilized and cycled in the ecosystem. We analyzed the acquisition of 15N label in mycorrhizal and non-mycorrhiza......15N labeled ammonium, glycine or glutamic acid was injected into subarctic heath soil in situ, with the purpose of investigating how the nitrogen added in these pulses was subsequently utilized and cycled in the ecosystem. We analyzed the acquisition of 15N label in mycorrhizal and non...

  5. Nitrogen uptake and balance of the fertilizers urea, urea with urease inhibitor, and ammonium nitrate applied to spring wheat at stem elongation growth stage

    International Nuclear Information System (INIS)

    Matzel, W.; Lippold, H.; Heber, R.

    1979-01-01

    The use of urea containing 1% of diamido phosphoric acid phenyl ester, which is a urease inhibitor, for the top dressing of spring wheat on light soil allows the loss of nitrogen due to volatilization of ammonia from urea to be prevented. The urease inhibitor has no effect whatsoever upon the uptake of urea nitrogen by spring wheat. Even in those cases where the volatilization of ammonia is prevented, plants will take up 5 to 6% less nitrogen from urea than from ammonium nitrate. This is due primarily to the higher degree of immobilization of urea nitrogen in the soil. The volatilization of ammonia from urea applied to the surface of the soil was in the region of 25% when the soil surface was moist and 10% when the soil surface was dry, the percentages given above being related to the amount of fertilizer nitrogen applied to the soil. The plant uptake of fertilizer nitrogen applied as a second dose at stem elongation will be complete after two to three weeks or after six weeks under favourable or unfavourable conditions, respectively. Proceeding immediately after application of the fertilizer nitrogen are the processes resulting in both loss of nitrogen and its immobilization. The proportion of absorbed fertilizer nitrogen recovered in the grain will be the greater the later the nitrogen is incorporated into the plant. The use in pot experiments of labelled nitrogen fertilizers enables statistically significant differences in effects to be determined even in those cases in which the differences are only relatively small in degree. (author)

  6. Nitrogen source for uptake by Gyrodinium cf. aureolum in a tidal front

    Digital Repository Service at National Institute of Oceanography (India)

    LeCorre, P.; L'Helguen, S.; Wafar, M.V.M.

    or ammonium that is critical to its suc- cess, however (it can do both, Dixon and Hol- ligan 1989; our results), but it is a question of in what form the N is immediately available for continued uptake and growth. In this con- text our results on N...- bial loop would provide the N necessary for G. aureolum development. The entire sequence can be summarized by comparing the distribution of N in the eu- photic zone in well-mixed waters (M2), a con- dition that exists before G. aureolum prolif...

  7. Early sowing increases nitrogen uptake and yields of winter wheat grown with cattle slurry or mineral fertilizers

    DEFF Research Database (Denmark)

    Suarez, Alfonso; Rasmussen, Jim; Thomsen, Ingrid Kaag

    2018-01-01

    of the two cultivars did not differ consistently with respect to the effect of early sowing on crop yield, N concentration and offtake, or ANR. Within the north-west European climatic region, moving the sowing time of winter wheat from mid-September to mid-August provides a significant yield and N offtake......The current study evaluated the effect of sowing date (early, mid-August or timely, mid-September) on two winter wheat (Triticum aestivum L.) cultivars (Hereford, Mariboss) with different rates of nitrogen (N) (0–225 kg total N/ha) applied as animal manure (AM; cattle slurry) or mineral fertilizers...... (N: phosphorus: potassium; NPK). Overwinter plant N uptake and soil mineral N content were determined during 2014/15, while harvest yields (grain, straw, N content) were determined during 2014/15 and 2015/16. Overwinter uptake of N was 14 kg N/ha higher in early than in timely-sown wheat. Despite...

  8. Nitrogen

    Science.gov (United States)

    Apodaca, Lori E.

    2013-01-01

    The article presents an overview of the nitrogen chemical market as of July 2013, including the production of ammonia compounds. Industrial uses for ammonia include fertilizers, explosives, and plastics. Other topics include industrial capacity of U.S. ammonia producers CF Industries Holdings Inc., Koch Nitrogen Co., PCS Nitrogen, Inc., and Agrium Inc., the impact of natural gas prices on the nitrogen industry, and demand for corn crops for ethanol production.

  9. Response of soil methane uptake to simulated nitrogen deposition and grazing management across three types of steppe in Inner Mongolia, China.

    Science.gov (United States)

    Li, Xianglan; He, Hong; Yuan, Wenping; Li, Linghao; Xu, Wenfang; Liu, Wei; Shi, Huiqiu; Hou, Longyu; Chen, Jiquan; Wang, Zhiping

    2018-01-15

    The response of soil methane (CH 4 ) uptake to increased nitrogen (N) deposition and grazing management was studied in three types of steppe (i.e., meadow steppe, typical steppe, and desert steppe) in Inner Mongolia, China. The experiment was designed with four simulated N deposition rates such as 0, 50, 100, and 200kgNha -1 , respectively, under grazed and fenced management treatments. Results showed that the investigated steppes were significant sinks for CH 4 , with an uptake flux of 1.12-3.36kgha -1 over the grass growing season and that the magnitude of CH 4 uptake significantly (Prates. The soil CH 4 uptake rates were highest in the desert steppe, moderate in the typical steppe, and lowest in the meadow steppe. Compared with grazed plots, fencing increased the CH 4 uptake by 4.7-40.2% with a mean value of 20.2% across the three different steppe types. The responses of soil CH 4 uptake to N deposition in the continental steppe varied depending on the N deposition rate, steppe type, and grazing management. A significantly positive correlation between CH 4 uptake and soil temperature was found in this study, whereas no significant relationship between soil moisture and CH 4 uptake occurred. Our results may contribute to the improvement of model parameterization for simulating biosphere-atmosphere CH 4 exchange processes and for evaluating the climate change feedback on CH 4 soil uptake. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Effects of arbuscular mycorrhizal fungi on growth and nitrogen uptake of Chrysanthemum morifolium under salt stress.

    Science.gov (United States)

    Wang, Yanhong; Wang, Minqiang; Li, Yan; Wu, Aiping; Huang, Juying

    2018-01-01

    Soil salinity is a common and serious environmental problem worldwide. Arbuscular mycorrhizal fungi (AMF) are considered as bio-ameliorators of soil salinity tolerance in plants. However, few studies have addressed the possible benefits of AMF inoculation for medicinal plants under saline conditions. In this study, we examined the effects of colonization with two AMF, Funneliformis mosseae and Diversispora versiformis, alone and in combination, on the growth and nutrient uptake of the medicinal plant Chrysanthemum morifolium (Hangbaiju) in a greenhouse salt stress experiment. After 6 weeks of a non-saline pretreatment, Hangbaiju plants with and without AMF were grown for five months under salinity levels that were achieved using 0, 50 and 200 mM NaCl. Root length, shoot and root dry weight, total dry weight, and root N concentration were higher in the mycorrhizal plants than in the non-mycorrhizal plants under conditions of moderate salinity, especially with D. versiformis colonization. As salinity increased, mycorrhizal colonization and mycorrhizal dependence decreased. The enhancement of root N uptake is probably the main mechanism underlying salt tolerance in mycorrhizal plants. These results suggest that the symbiotic associations between the fungus D. versiformis and C. morifolium plants may be useful in biotechnological practice.

  11. Adaptations of hepatic amino acid uptake and net utilisation contributes to nitrogen economy or waste in lambs fed nitrogen- or energy-deficient diets.

    Science.gov (United States)

    Kraft, G; Ortigues-Marty, I; Durand, D; Rémond, D; Jardé, T; Bequette, B; Savary-Auzeloux, I

    2011-04-01

    We investigated the effect of relative changes in dietary nitrogen (N) and energy supply and the subsequent variations in net portal appearance (NPA) of nitrogenous and energy nutrients on the net amino acid (AA) uptake by the liver and net N supply to the peripheral tissues. Six lambs were catheterised across the splanchnic tissues and received, in a replicated Latin square, one of three dietary treatments. The diets were formulated to either match the requirements of N and energy (C), or supply only 0.8 of the N requirement (LN) or 0.8 of the energy requirement (LE). Net fluxes of AA and urea-N were measured across the portal-drained viscera, and estimation of arterial hepatic flow allowed the estimation of hepatic fluxes. Catheters were implanted into the portal and hepatic veins as well as in the abdominal aorta for the measurement of AA fluxes. Animals fed the LN diet showed more efficient N retention (0.59 of digested N) than did the C and LE diet (0.50 and 0.33, respectively; P < 0.001). The NPA of total AA-N for the LN diet was only 0.60 of the value measured for the control (C) diet (P < 0.01). Despite this, the total estimated AA-N net splanchnic fluxes were not significantly different across the three diets (3.3, 1.9 and 2.6 g total AA-N/day for C, LN and LE, respectively, P = 0.52). Thus, different metabolic regulations must have taken place across the liver between the three experimental diets. A combination of decreased net uptake of total AA-N by the liver of animals in the LN diet (0.61 of the C diet; P = 0.002) and reduced urinary urea-N production (0.52 of the C diet; P = 0.001) spared AA from catabolism in the LN diet relative to the other two diets. For the LE diet, the urinary urea-N output was 1.3 times the value of the C diet (P = 0.01). This may relate to an increased catabolism of AA by the muscle and/or, to a lesser extent, to an increased utilisation of AA for gluconeogenesis in the liver. These effects may explain the reduced whole body

  12. Nitrogen nutrition of Canna indica: Effects of ammonium versus nitrate on growth, biomass allocation, photosynthesis, nitrate reductase activity and N uptake rates

    DEFF Research Database (Denmark)

    Konnerup, Dennis; Brix, Hans

    2010-01-01

    The effects of inorganic nitrogen (N) source (NH4+, NO3- or both) on growth, biomass allocation, photosynthesis, N uptake rate, nitrate reductase activity and mineral composition of Canna indica were studied in hydroponic culture. The relative growth rates (0.05-0.06 g g-1 d-1), biomass allocation...

  13. In Situ Activation of Nitrogen-Doped Graphene Anchored on Graphite Foam for a High-Capacity Anode.

    Science.gov (United States)

    Ji, Junyi; Liu, Jilei; Lai, Linfei; Zhao, Xin; Zhen, Yongda; Lin, Jianyi; Zhu, Yanwu; Ji, Hengxing; Zhang, Li Li; Ruoff, Rodney S

    2015-08-25

    We report the fabrication of a three-dimensional free-standing nitrogen-doped porous graphene/graphite foam by in situ activation of nitrogen-doped graphene on highly conductive graphite foam (GF). After in situ activation, intimate "sheet contact" was observed between the graphene sheets and the GF. The sheet contact produced by in situ activation is found to be superior to the "point contact" obtained by the traditional drop-casting method and facilitates electron transfer. Due to the intimate contact as well as the use of an ultralight GF current collector, the composite electrode delivers a gravimetric capacity of 642 mAh g(-1) and a volumetric capacity of 602 mAh cm(-3) with respect to the whole electrode mass and volume (including the active materials and the GF current collector). When normalized based on the mass of the active material, the composite electrode delivers a high specific capacity of up to 1687 mAh g(-1), which is superior to that of most graphene-based electrodes. Also, after ∼90 s charging, the anode delivers a capacity of about 100 mAh g(-1) (with respect to the total mass of the electrode), indicating its potential use in high-rate lithium-ion batteries.

  14. Use of sewage sludge - nitrogen availability and heavy metal uptake into rape

    International Nuclear Information System (INIS)

    Gerzabek, M. H.; Lombi, E.; Herger, P.

    1998-07-01

    The results of a three years experiment with large pots in the field evaluating the effects of sewage sludge (sterilised by γ-irradiation or not sterilised) on rape growth, heavy metal-and N-uptake, using the 15 N-dilution technique, are presented. Mobile fractions of Cd, Cu and Zn increased significantly in the substrate due to sewage sludge treatments. However heavy metal transfer into rape plants did not respond clearly. Rape growth was clearly enhanced in the first and third year due to sewage sludge applications. The average N-utilization by rape from sewage sludge in a three years period decreased from 7.4 % (first year), 1.8 % (second year) to 1.1 % (third year), resulting in an overall utilization of 10.3 % of sewage sludge - N t by rape plants. Irradiation of sewage sludge did not result in any significant effect on the investigated parameters. (author)

  15. Identification of QTL Associated with Nitrogen Uptake and Nitrogen Use Efficiency Using High Throughput Genotyped CSSLs in Rice (Oryza sativa L.

    Directory of Open Access Journals (Sweden)

    Yong Zhou

    2017-07-01

    Full Text Available Nitrogen (N availability is a major factor limiting crop growth and development. Identification of quantitative trait loci (QTL for N uptake (NUP and N use efficiency (NUE can provide useful information regarding the genetic basis of these traits and their associated effects on yield production. In this study, a set of high throughput genotyped chromosome segment substitution lines (CSSLs derived from a cross between recipient 9311 and donor Nipponbare were used to identify QTL for rice NUP and NUE. Using high throughput sequencing, each CSSL were genotyped and an ultra-high-quality physical map was constructed. A total of 13 QTL, seven for NUP and six for NUE, were identified in plants under hydroponic culture with all nutrients supplied in sufficient quantities. The proportion of phenotypic variation explained by these QTL for NUP and NUE ranged from 3.16–13.99% and 3.76–12.34%, respectively. We also identified several QTL for biomass yield (BY and grain yield (GY, which were responsible for 3.21–45.54% and 6.28–7.31%, respectively, of observed phenotypic variation. GY were significantly positively correlated with NUP and NUE, with NUP more closely correlated than NUE. Our results contribute information to NUP and NUE improvement in rice.

  16. Yield, nitrogen uptake and nitrogen use efficiency by tomato, pepper, cucumber, melon and eggplant as affected by nitrogen rates applied with drip-irrigation under greenhouse conditions

    International Nuclear Information System (INIS)

    Halitligil, M.B.; Akin, A.I.; Kislal, H.; Ozturk, A.; Deviren, A.

    2002-01-01

    A number of experiments were conducted to investigate the influence of different N rates applied through drip irrigation on the growth and N uptake by tomato, pepper, cucumber, melon and eggplant under greenhouse conditions. It was found that, for tomato, the % NUE was significantly increased by applying the N fertilizer through fertigation (53.9%) as compared to the soil application (34.0%) at 100 mg N/L. In general, any further increase of N fertilizer did not have an improving effect on the tomato yield. With pepper, the % NUE was significantly increased by applying the N fertilizer in the irrigation water (49.2%) as compared to the soil application (33.9%) at the same N level (140 mg N/L), being the optimum N rate under our greenhouse conditions. At a fertilization level of 100 mg N/L with fertigation, the % NUE was significantly increased as compared to the soil application. With respectively cucumber, melon and eggplant; the % NUE with fertigation was 63.4, 21.4 and 50.8%, while with soil application it was 34,0 11.0 and 18.8%. (author)

  17. Suppression of temperature instability in InGaZnO thin-film transistors by in situ nitrogen doping

    International Nuclear Information System (INIS)

    Raja, Jayapal; Jang, Kyungsoo; Yi, Junsin; Balaji, Nagarajan

    2013-01-01

    We have investigated the effect of nitrogen doping on the behavior of hysteresis curve and its suppression of temperature instability in amorphous InGaZnO thin-film transistors (a-IGZO TFTs). The in situ nitrogen doping reduced the temperature induced abnormal sub threshold leakage current and traps generation. Large falling-rate (F R ) ∼ 0.26 eV V −1 , low activation energy (E a ) ∼ 0.617 eV and a small hysteresis compared to the pure a-IGZO TFTs, shows the best immunity to thermal instability. This is mainly attributed to the reduction of interface trap density and oxygen vacancies due to the passivation of defects and/dangling bonds. (paper)

  18. EFFECT OF IRRIGATION WITH SEWAGE WASTEWATER ON NITROGEN UPTAKE AND TRANSLOCATION BY NAVEL ORANGE TRANSPLANTS USING 15N-LABELLED AMMONIUM SULPHATE

    International Nuclear Information System (INIS)

    EL-MOTAIUM, R.A.; SHARAF, A.N.; HASHEM, M.E.; HEGAZI, E.S.; BADAWY, S.H.

    2009-01-01

    An isotope aided study using 15 N-labelled ammonium sulphate was applied to investigate nitrogen uptake and translocation from sewage water by one year old Navel orange transplants. The investigation was conducted in a pot experiment at the greenhouse for two successive seasons (2005 and 2006). Ammonium sulphate was applied to the soil at a rate of 6 g/pot. The treatments included irrigation with canal water and sewage water. Half strength Hoagland nutrient solution, nitrogen depleted, was applied to provide the required nutrients for healthy growth of the transplants. The pots were irrigated to maintain the soil moisture content at field capacity.The results indicated that there is an increase in the transplants biomass irrigated with sewage water than using canal water. A substantial increase in mineral fertilizer nitrogen ( 15 N) uptake by plant roots and translocation into shoots was observed using canal water than sewage water. The nitrogen percent derived from sewage water was higher (26.1-49.5%) than that derived from 15 N-labelled ammonium sulphate (4.9-12.7%). Fertilizer nitrogen recovery was higher under canal water than under sewage water irrigation regime, although the plant biomass was higher under sewage water. Using sewage water alone can provide the orange transplants with their nitrogen requirements with no need for application of mineral fertilizer

  19. In situ self-sacrificed template synthesis of vanadium nitride/nitrogen-doped graphene nanocomposites for electrochemical capacitors.

    Science.gov (United States)

    Liu, Hong-Hui; Zhang, Hong-Ling; Xu, Hong-Bin; Lou, Tai-Ping; Sui, Zhi-Tong; Zhang, Yi

    2018-03-15

    Vanadium nitride and graphene have been widely used as pseudo-capacitive and electric double-layer capacitor electrode materials for electrochemical capacitors, respectively. However, the poor cycling stability of vanadium nitride and the low capacitance of graphene impeded their practical applications. Herein, we demonstrated an in situ self-sacrificed template method for the synthesis of vanadium nitride/nitrogen-doped graphene (VN/NGr) nanocomposites by the pyrolysis of a mixture of dicyandiamide, glucose, and NH 4 VO 3 . Vanadium nitride nanoparticles of the size in the range of 2 to 7 nm were uniformly embedded into the nitrogen-doped graphene skeleton. Furthermore, the VN/NGr nanocomposites with a high specific surface area and pore volume showed a high specific capacitance of 255 F g -1 at 10 mV s -1 , and an excellent cycling stability (94% capacitance retention after 2000 cycles). The excellent capacitive properties were ascribed to the excellent conductivity of nitrogen-doped graphene, high surface area, high pore volume, and the synergistic effect between vanadium nitride and nitrogen-doped graphene.

  20. Optimizing nitrogen uptake efficiency by irrigated wheat to reduce environmental pollution

    International Nuclear Information System (INIS)

    Arslan, A.; Kurdali, F.; Al-Shayeb, R.

    2000-01-01

    Two wheat cultivars (Sham 3 and Sham 6) were grown after fallow for two seasons and after wheat for another two seasons, with sprinkler irrigation. Four N-fertilizer rates (0, 50, 100, and 150% of the recommended dose) were used. A neutron moisture probe was used to determine the time and amount of irrigation. Nitrogen-15 was used to determine the fate of fertilizer N. Porous ceramic samplers were installed at different depths in micro-plots fertilized with 15 N to monitor its movement in the soil. Dry biomass and grain yield of wheat after fallow were much higher than those of wheat after wheat. The effects of increasing amounts of N fertilizer were significant during the four seasons, but were more pronounced in wheat after wheat. The appropriate timing and amount of irrigation water contributed to high fertilizer-N recovery (between 44 and 75%). Plants recovered N fertilizer applied at tillering more efficiently than when it was applied at germination. Labelled N analysis showed no deep percolation of N fertilizer with water during the same growing season. Water use efficiency of wheat after fallow was almost twice that of wheat after wheat, and N fertilization of wheat after wheat increased the water use efficiency two to three fold. Chlorophyll readings with all treatments were high during the first and second seasons, especially those fertilized with the recommended N rate or more. These results were in agreement with Ceres-Wheat model output, where it did not predict any N stress. Nitrogen deficit was observed by eye, and was indicated by the Ceres-Wheat model and chlorophyll-meter readings on plants fertilized with low rates of N during the last two seasons. Acceptable agreement was observed between model prediction of soil-water content and that determined using isotopic techniques, and between observed and predicted grain yields and biomass, N yields of grain and total N yields. However, predictions of the model for some variables were weak-, indicating a

  1. Evaluation of Upland Rice Genotypes for Efficient Uptake of Nitrogen and Phosphorus

    Energy Technology Data Exchange (ETDEWEB)

    Zaharah, A. R.; Hanafi, M. M. [Universiti Putra Malaysia, Serdang, Selangor (Malaysia)

    2013-11-15

    Upland rice grown by subsistence farmers in the tropics and subtropics is known to produce very low yields due to it being planted on low fertility soils and under drought-prone conditions. Little information is available on upland rice cultivar differences in response to N and P fertilization in Asia, thus screening for P (PUE) and N use efficiency (NUE) of upland rice genotypes is a necessary first step. The objectives of the study were: (i) to identify upland rice genotypes with root characteristics favorable for efficient N and P uptake and utilization, (ii) to evaluate the selected genotypes for their grain yield, and (iii) to assess the variability of N and P use efficiency in upland rice genotypes grown under field conditions. Several laboratory, glasshouse and field experiments were carried out from 2007 to 2011 at Universiti Putra Malaysia to achieve the above objectives. Fifteen local and 15 upland rice genotypes from WARDA were identified to have long roots, and it was observed that some of the WARDA lines showed longer root length than the local landraces. This is a good trait since it is known that longer root length will enhance the absorption of easily mobile nutrients such as nitrate and potassium. Glasshouse and field evaluation of N use efficiency by these upland rice genotypes showed that high N is utilized (40-80% of applied N), with good grain yield, and P use efficiency is similar to other crops (4-8%). (author)

  2. Spectral Indices to Monitor Nitrogen-Driven Carbon Uptake in Field Corn

    Science.gov (United States)

    Corp, Lawrence A.; Middleton, Elizabeth M.; Campbell, Peya E.; Huemmrich, K. Fred; Daughtry, Craig S. T.; Russ, Andrew; Cheng, Yen-Ben

    2010-01-01

    Climate change is heavily impacted by changing vegetation cover and productivity with large scale monitoring of vegetation only possible with remote sensing techniques. The goal of this effort was to evaluate existing reflectance (R) spectroscopic methods for determining vegetation parameters related to photosynthetic function and carbon (C) dynamics in plants. Since nitrogen (N) is a key constituent of photosynthetic pigments and C fixing enzymes, biological C sequestration is regulated in part by N availability. Spectral R information was obtained from field corn grown at four N application rates (0, 70, 140, 280 kg N/ha). A hierarchy of spectral observations were obtained: leaf and canopy with a spectral radiometer; aircraft with the AISA sensor; and satellite with EO-1 Hyperion. A number of spectral R indices were calculated from these hyperspectral observations and compared to geo-located biophysical measures of plant growth and physiological condition. Top performing indices included the R derivative index D730/D705 and the normalized difference of R750 vs. R705 (ND705), both of which differentiated three of the four N fertilization rates at multiple observation levels and yielded high correlations to these carbon parameters: light use efficiency (LUE); C:N ratio; and crop grain yield. These results advocate the use of hyperspectral sensors for remotely monitoring carbon cycle dynamics in managed terrestrial ecosystems.

  3. Nitrogen and phosphorous limitation reduces the effects of land use change on land carbon uptake or emission

    International Nuclear Information System (INIS)

    Wang, Ying-Ping; Zhang, Qian; Dai, Yongjiu; Pitman, Andrew J

    2015-01-01

    We used an Earth System Model that includes both nitrogen (N) and phosphorus (P) cycling to simulate the impacts of land-use and land-cover change (LULCC) for two representative concentration pathways (RCPs): a reforestation scenario (RCP4.5) and a deforestation scenario (RCP8.5). For each RCP, we performed simulations with and without LULCC using the carbon (C only) mode or including the full C, N and P cycles (CNP). We show, for the first time, that inclusion of N and P cycling reduces both the carbon uptake from reforestation in RCP4.5 and the carbon emission from deforestation in RCP8.5. Specifically, carbon-nutrient interaction reduces carbon uptake in RCP4.5 from 55 Pg C (C only) to 21 Pg C (CNP), or the emissions in RCP8.5 from 72 Pg C (C only) to 56 Pg C (CNP). Most of those reductions result from much weaker responses of net primary production to CO 2 fertilization and climate change when carbon-nutrient interaction is taken into account, as compared to C only simulations. Our results highlight the importance of including nutrient-carbon interaction in estimating the carbon benefit from reforestation and carbon loss from deforestation in a future world with higher CO 2 and a warmer climate. Because of the stronger nutrient limitation, carbon gain from reforestation in the temperate and boreal regions is much less than the carbon loss from deforestation in the subtropical and tropical regions from 2006 to 2100 for the two RCPs. Therefore protecting the existing subtropical and tropical forests is about twice as effective as planting new forests in the temperate and boreal regions for climate mitigation. (letter)

  4. Bryophytes and Organic layers Control Uptake of Airborne Nitrogen in Low-N Environments

    Science.gov (United States)

    Bähring, Alexandra; Fichtner, Andreas; Friedrich, Uta; von Oheimb, Goddert; Härdtle, Werner

    2017-01-01

    The effects of atmospheric nitrogen (N) deposition on ecosystem functioning largely depend on the retention of N in different ecosystem compartments, but accumulation and partitioning processes have rarely been quantified in long-term field experiments. In the present study we analysed for the first time decadal-scale flows and allocation patterns of N in a heathland ecosystem that has been subject to airborne N inputs over decades. Using a long-term 15N tracer experiment, we quantified N retention and flows to and between ecosystem compartments (above-ground/below-ground vascular biomass, moss layer, soil horizons, leachate). After 9 years, about 60% of the added 15N-tracer remained in the N cycle of the ecosystem. The moss layer proved to be a crucial link between incoming N and its allocation to different ecosystem compartments (in terms of a short-term capture, but long-term release function). However, about 50% of the 15N captured and released by the moss layer was not compensated for by a corresponding increase in recovery rates in any other compartment, probably due to denitrification losses from the moss layer in the case of water saturation after rain events. The O-horizon proved to be the most important long-term sink for added 15N, as reflected by an increase in recovery rates from 18 to 40% within 8 years. Less than 2.1% of 15N were recovered in the podzol-B-horizon, suggesting that only negligible amounts of N were withdrawn from the N cycle of the ecosystem. Moreover, 15N recovery was low in the dwarf shrub above-ground biomass (account for cumulative effects of N additions into ecosystems. PMID:29375589

  5. Biological Nitrogen Fixation by Legumes and N Uptake by Coffee Plants

    Directory of Open Access Journals (Sweden)

    Eduardo de Sá Mendonça

    Full Text Available ABSTRACT Green manures are an alternative for substituting or supplementing mineral nitrogen fertilizers. The aim of this study was to quantify biological N fixation (BNF and the N contribution derived from BNF (N-BNF to N levels in leaves of coffee intercropped with legumes grown on four family farms located in the mountainous region of the Atlantic Forest Biome in the state of Minas Gerais, Brazil. The following green manures were evaluated: pinto peanuts (Arachis pintoi, calopo (Calopogonium mucunoides, crotalaria (Crotalaria spectabilis, Brazilian stylo (Stylosanthes guianensis, pigeon pea (Cajanus cajan, lablab beans (Dolichos lablab, and velvet beans (Stizolobium deeringianum, and spontaneous plants. The experimental design was randomized blocks with a 4 × 8 factorial arrangement (four agricultural properties and eight green manures, and four replications. One hundred grams of fresh matter of each green manure plant were dried in an oven to obtain the dry matter. We then performed chemical and biochemical characterizations and determined the levels of 15N and 14N, which were used to quantify BNF through the 15N (δ15N natural abundance technique. The legumes C. mucunoides, S. guianensis, C. cajan, and D. lablab had the highest rates of BNF, at 46.1, 45.9, 44.4, and 42.9 %, respectively. C. cajan was the legume that contributed the largest amount of N (44.42 kg ha-1 via BNF.C. cajan, C. spectabilis, and C. mucunoides transferred 55.8, 48.8, and 48.1 %, respectively, of the N from biological fixation to the coffee plants. The use of legumes intercropped with coffee plants is important in supplying N, as well as in transferring N derived from BNF to nutrition of the coffee plants.

  6. Nutrient limitation reduces land carbon uptake in simulations with a model of combined carbon, nitrogen and phosphorus cycling

    Directory of Open Access Journals (Sweden)

    D. S. Goll

    2012-09-01

    Full Text Available Terrestrial carbon (C cycle models applied for climate projections simulate a strong increase in net primary productivity (NPP due to elevated atmospheric CO2 concentration during the 21st century. These models usually neglect the limited availability of nitrogen (N and phosphorus (P, nutrients that commonly limit plant growth and soil carbon turnover. To investigate how the projected C sequestration is altered when stoichiometric constraints on C cycling are considered, we incorporated a P cycle into the land surface model JSBACH (Jena Scheme for Biosphere–Atmosphere Coupling in Hamburg, which already includes representations of coupled C and N cycles.

    The model reveals a distinct geographic pattern of P and N limitation. Under the SRES (Special Report on Emissions Scenarios A1B scenario, the accumulated land C uptake between 1860 and 2100 is 13% (particularly at high latitudes and 16% (particularly at low latitudes lower in simulations with N and P cycling, respectively, than in simulations without nutrient cycles. The combined effect of both nutrients reduces land C uptake by 25% compared to simulations without N or P cycling. Nutrient limitation in general may be biased by the model simplicity, but the ranking of limitations is robust against the parameterization and the inflexibility of stoichiometry. After 2100, increased temperature and high CO2 concentration cause a shift from N to P limitation at high latitudes, while nutrient limitation in the tropics declines. The increase in P limitation at high-latitudes is induced by a strong increase in NPP and the low P sorption capacity of soils, while a decline in tropical NPP due to high autotrophic respiration rates alleviates N and P limitations. The quantification of P limitation remains challenging. The poorly constrained processes of soil P sorption and biochemical mineralization are identified as the main uncertainties in the strength of P limitation

  7. Integrating environmental and in situ hyperspectral remote sensing variables for grass nitrogen estimation in savannah ecosystems

    CSIR Research Space (South Africa)

    Ramoelo, Abel

    2011-04-01

    Full Text Available Information about the distribution of grass nitrogen (N) concentration is crucial in understanding rangeland vitality and facilitates effective management of wildlife and livestock. A challenge in estimating grass N concentration using remote...

  8. Bryophytes and Organic layers Control Uptake of Airborne Nitrogen in Low-N Environments

    Directory of Open Access Journals (Sweden)

    Alexandra Bähring

    2017-12-01

    Full Text Available The effects of atmospheric nitrogen (N deposition on ecosystem functioning largely depend on the retention of N in different ecosystem compartments, but accumulation and partitioning processes have rarely been quantified in long-term field experiments. In the present study we analysed for the first time decadal-scale flows and allocation patterns of N in a heathland ecosystem that has been subject to airborne N inputs over decades. Using a long-term 15N tracer experiment, we quantified N retention and flows to and between ecosystem compartments (above-ground/below-ground vascular biomass, moss layer, soil horizons, leachate. After 9 years, about 60% of the added 15N-tracer remained in the N cycle of the ecosystem. The moss layer proved to be a crucial link between incoming N and its allocation to different ecosystem compartments (in terms of a short-term capture, but long-term release function. However, about 50% of the 15N captured and released by the moss layer was not compensated for by a corresponding increase in recovery rates in any other compartment, probably due to denitrification losses from the moss layer in the case of water saturation after rain events. The O-horizon proved to be the most important long-term sink for added 15N, as reflected by an increase in recovery rates from 18 to 40% within 8 years. Less than 2.1% of 15N were recovered in the podzol-B-horizon, suggesting that only negligible amounts of N were withdrawn from the N cycle of the ecosystem. Moreover, 15N recovery was low in the dwarf shrub above-ground biomass (<3.9% after 9 years and in the leachate (about 0.03% within 1 year, indicating still conservative N cycles of the ecosystem, even after decades of N inputs beyond critical load thresholds. The continuous accumulation of reactive forms of airborne N suggests that critical load-estimates need to account for cumulative effects of N additions into ecosystems.

  9. Nitrogen uptake and assimilation by two families of loblolly pine under simulated field conditions in the greenhouse

    International Nuclear Information System (INIS)

    White, T.A.

    1989-01-01

    While significant success has been achieved in pine tree improvement, comparatively little is known about the physiological strategies employed by superior genotypes. The central hypothesis of this research was that dissimilarities of two families of loblolly pine (Pinus taeda L.) in absorption, use, and allocation of N and C during and after periods of N stress explain differences in productivity. One group of trees was exposed to NH 4 + -N (100:0 experiment) for 84 d while a second group was grown with a 70% NH 4 + : 30% NO 3 - -N solution (70:30 experiment). Ammonium-N was labelled with 15 N. Half of the seedlings had restricted N supplies from 28 d to 70 d. Results were compared to the unstressed half of each group. Nitrogen stress resulted in significantly lower biomass production and N uptake in both families in the 70:30 experiment. The superior family recovered these losses 14 d after the N stress was removed. No difference in biomass existed in either family following N stress in the 100:0 experiment

  10. Nitrogen effects on mobility and plant uptake of heavy metals in sewage sludge applied to soil columns

    Energy Technology Data Exchange (ETDEWEB)

    Giordano, P.M.; Mortvedt, J.J.

    1976-01-01

    Cation movement in soil under leaching conditions has been associated with N fertilization. Therefore, this study was conducted to determine whether the mobility of some heavy metals applied in the inorganic form or in sewage sludge is enhanced in the presence of various sources of N. Columns of heavy metal-amended soil in plastic well casings were cropped with tall fescue (Festuca arundinacea Schreb.) and leached three times with deionized H/sub 2/O. Heavy metal concentrations above check values were not detected in leachates from any column. Mobility of the heavy metals from the inorganic sources was slightly greater than that from the sewage sludge. Nitrogen fertilization did not affect the downward movement of Zn, Cd, Cr, Pb, or Ni in soil but enhanced uptake of these metals by fescue because of increased growth. These results suggest that heavy metal contamination of ground water is not likely in heavy textured soils when sewage sludge applications are accompanied by N fertilization, at least for short periods of time. 11 references, 1 figure, 4 tables.

  11. Anthropogenic nitrogen input traced by means of δ 15N values in macroalgae: Results from in-situ incubation experiments

    International Nuclear Information System (INIS)

    Deutsch, Barbara; Voss, Maren

    2006-01-01

    The macroalgae species Fucus vesiculosus (Phaeophyta), Polysiphonia sp., and Ceramium rubrum (Rhodophyta) originally grown at an unpolluted brackish site of the southern Baltic Sea were incubated for 10 and 14 days at 12 stations along a salinity gradient in a highly polluted estuary. We have expected an adaptation of the initially low δ 15 N values to the higher ones within the incubation period. In addition to the macroalgae the δ 15 N values of NO 3 - were measured to evaluate fractionation processes of the source nitrate. Inside the estuary, δ 15 N-NO 3 - values were 6.2-9.7 per mille , indicating anthropogenic nitrogen sources. The red macroalgae adequately reflected the nitrate isotope values in the surrounding waters, whereas for F. vesiculosus the results were not that clear. The reasons were assumed to be higher initial δ 15 N values of F. vesiculosus and presumably a too slow nitrogen uptake and growth rate. The method of macroalgae incubations seems suitable as a simple monitoring to study the influence of anthropogenic nitrogen loading in an estuarine environment

  12. A New Oidiodendron maius Strain Isolated from Rhododendron fortunei and Its Effects on Nitrogen Uptake and Plant Growth

    Directory of Open Access Journals (Sweden)

    Xiangying Wei

    2016-08-01

    Full Text Available A new mycorrhizal fungal strain was isolated from hair roots of Rhododendron fortunei Lindl. grown in Huading Forest Park, Zhejiang Province, China. Morphological characterization and internal transcribed spacer (ITS rDNA analysis suggested that it belongs to Oidiodendron maius Barron, and we designated it as strain Om19. Methods for culturing Om19 were established, and the ability of Om19 to form mycorrhizae on R. fortunei was evaluated in a peat-based substrate. Microscopic observations showed hyaline hyphae on the surface of hair roots and crowded hyphal complexes (hyphal coils inside root cortical cells of R. fortunei after inoculation, indicating that the roots were well colonized by Om19. In a second experiment, fresh and dry weight of R. fortunei two months after Om19 inoculation were greater than uninoculated plants, and the total nitrogen (N absorbed by plants inoculated with Om19 was greater than the uninoculated controls. qRT-PCR analysis of five genes related to N uptake and metabolism (two nitrate transporters, an ammonium transporter, glutamine synthetase, and glutamate synthase showed that these genes were highly upregulated with 2 to 9 fold greater expression in plants inoculated with Om19 compared to uninoculated plants. In the third experiment, Om19 was inoculated into the peat-based substrate for growing Formosa azalea (R. indica ‘Formosa’. ‘Formosa’ azalea plants grown in the inoculated substrate had larger canopies and root systems compared to uninoculated plants. Our results show that Om19 could be an important microbial tool for improving production of Rhododendron plants.

  13. Effects of Land-Applied Ammonia Scrubber Solutions on Yield, Nitrogen Uptake, Soil Test Phosphorus, and Phosphorus Runoff.

    Science.gov (United States)

    Martin, Jerry W; Moore, Philip A; Li, Hong; Ashworth, Amanda J; Miles, Dana M

    2018-03-01

    Ammonia (NH) scrubbers reduce amounts of NH and dust released from animal rearing facilities while generating nitrogen (N)-rich solutions, which may be used as fertilizers. The objective of this study was to determine the effects of various NH scrubber solutions on forage yields, N uptake, soil-test phosphorus (P), and P runoff. A small plot study was conducted using six treatments: (i) an unfertilized control, (ii) potassium bisulfate (KHSO) scrubber solution, (iii) aluminum sulfate [Al(SO) ⋅14HO, alum] scrubber solution, (iv) sodium bisulfate (NaHSO) scrubber solution, (v) sulfuric acid (HSO) scrubber solution, and (vi) ammonium nitrate (NHNO) fertilizer. The scrubber solutions were obtained from ARS Air Scrubbers attached to commercial broiler houses. All N sources were applied at a rate of 112 kg N ha. Plots were harvested approximately every 4 wk and soil-test P measurements were made, then a rainfall simulation study was conducted. Cumulative forage yields were greater ( scrubber solutions than for alum (6.7 Mg ha) or HSO (6.5 Mg ha) scrubber solutions or for NHNO (6.9 Mg ha). All N sources resulted in higher yields than the control (5.1 Mg ha). The additional potassium in the KHSO treatment likely resulted in higher yields. Although Mehlich-III-extractable P was not affected, water-extractable P in soil was lowered by the alum-based scrubber solution, which also resulted in lower P runoff. This study demonstrates that N captured using NH scrubbers is a viable N fertilizer. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  14. The use of the short-lived radioisotopes 11C and 13N to study nitrogen uptake and photosynthate translocation in fodder beet

    International Nuclear Information System (INIS)

    McNaughton, G.S.; Minchin, P.E.H.

    1983-01-01

    Following discussions at the Nitrogen Balance Workshop held at Massey University, May 1980, on the use of the 10 min half-life isotope nitrogen-13, it was decided to carry out collaborative experiments with Dr K.M. Goh from Lincoln College. These were concerned with the mechanism of the effect of sodium chloride on the uptake of nitrate and ammonium ions by beet (Beta vulgaris L) plants. In this report we firstly summarize briefly some of the relevant literature then report on the experiments carried out to November 1982. The initial experiments used nitrogen-13 to investigate, with hydroponically grown plants, the effect of sodium chloride on the uptake by roots, and the transport to leaves, of nitrogen-13 applied to the roots as nitrate or as ammonium ions. After failing to find any response to NaCl in these experiments, it was decided to determine whether there was any effect of NaC1 on the transport of carbon-11 labelled photosynthates from the leaves. Production of this preliminary report is a first step to assessing the next phase, if any of this investigation

  15. The fate of fixed nitrogen in marine sediments with low organic loading: an in situ study

    DEFF Research Database (Denmark)

    Bonaglia, Stefano; Hylén, Astrid; Rattray, Jane E.

    2017-01-01

    Given the increasing impacts of human activities on global nitrogen (N) cycle, investigations on N transformation processes in the marine environment have drastically increased in the last years. Benthic N cycling has mainly been studied in anthropogenically impacted estuaries and coasts, while its...... sediments worldwide (range 34–344 µmol N m−2 d−1). Anammox accounted for 18–26 % of the total N2 production. Absence of free hydrogen sulfide and low concentrations of dissolved iron in sediment pore waters suggested that denitrification and DNRA were driven by organic matter oxidation rather than...... chemolithotrophy. DNRA was as important as denitrification at a shallow, coastal station situated in the northern Bothnian Bay. At this pristine and fully oxygenated site, ammonium regeneration through DNRA contributed more than one third to the total dissolved nitrogen (TDN) diffusing from the sediment...

  16. Nitrogen Fertilizer and Straw Applications Affect Uptake of 13C,15N-Glycine by Soil Microorganisms in Wheat Growth Stages.

    Directory of Open Access Journals (Sweden)

    Lijie Yang

    Full Text Available This study investigated the influence of nitrogen (N fertilizer and straw on intact amino acid N uptake by soil microorganisms and the relationship between amino acid turnover and soil properties during the wheat growing season. A wheat pot experiment was carried out with three treatments: control (CK, N fertilizer (NF and N fertilizer plus rice straw (NS. We used stable isotope compound-specific analysis to determine the uptake of 13C,15N-glycine by soil microorganisms. In the NF treatment, microbial 13C,15N-glycine uptake was lower compared with CK, suggesting that inorganic N was the preferred N source for soil microorganisms. However, The application of straw with N fertilizer (in NS treatment increased microbial 13C,15N-glycine uptake even with the same amount of N fertilizer application. In this treatment, enzyme activities, soil microbial biomass C and microbial biomass N increased simultaneously because more C was available. Soil mineral N and plant N contents all decreased substantially. The increased uptake of intact 13C,15N-glycine in the NS treatment can be attributed to direct assimilation by soil microorganisms to satisfy the demand for N when inorganic N was consumed.

  17. Nitrogen incorporation and retention by bacteria, algae, and fauna in a subtropical, intertidal sediment: An in situ 15N-labeling study

    NARCIS (Netherlands)

    Veuger, B.; Eyre, B.D.; Maher, D.; Middelburg, J.J.

    2007-01-01

    We performed a 15N-labeling study to investigate nitrogen incorporation and retention by the benthic microbial community (bacteria and benthic microalgae) and fauna in the intertidal sediment of the subtropical Australian Brunswick Estuary. The main experiment involved an in situ 15N pulse–chase

  18. Crop uptake and leaching losses of 15N labelled fertilizer nitrogen in relation to waterlogging of clay and sandy loam soils

    International Nuclear Information System (INIS)

    Webster, C.P.; Belford, R.K.; Cannell, R.Q.

    1986-01-01

    Ammonium nitrate fertilizer, labelled with 15 N, was applied in spring to winter wheat growing in undisturbed monoliths of clay and sandy loam soil in lysimeters; the rates of application were respectively 95 and 102 kg N ha -1 in the spring of 1976 and 1975. Crops of winter wheat, oilseed rape, peas and barley grown in the following 5 or 6 years were treated with unlabelled nitrogen fertilizer at rates recommended for maximum yields. During each year of the experiments the lysimeters were divided into treatments which were either freely drained or subjected to periods of waterlogging. Another labelled nitrogen application was made in 1980 to a separate group of lysimeters with a clay soil and a winter wheat crop to study further the uptake of nitrogen fertilizer in relation to waterlogging. In the first growing season, shoots of the winter wheater at harvest contained 46 and 58% of the fertilizer nitrogen applied to the clay and sandy loam soils respectively. In the following year the crops contained a further 1-2% of the labelled fertilizer, and after 5 and 6 years the total recoveries of labelled fertilizer in the crops were 49 and 62% on the clay and sandy loam soils respectively. In the first winter after the labelled fertilizer was applied, less than 1% of the fertilizer was lost in the drainage water, and only about 2% of the total nitrogen (mainly nitrate) in the drainage water from both soils was derived from the fertilizer

  19. Nitrogen

    Science.gov (United States)

    Apodaca, L.E.

    2010-01-01

    Ammonia was produced by 13 companies at 23 plants in 16 states during 2009. Sixty percent of all U.S. ammonia production capacity was centered in Louisiana. Oklahoma and Texas because of those states' large reserves of natural gas, the dominant domestic feedstock. In 2009, U.S. producers operated at about 83 percent of their rated capacity (excluding plants that were idle for the entire year). Five companies — Koch Nitrogen Co.; Terra Industries Inc.; CF Industries Inc.; PCS Nitrogen Inc. and Agrium Inc., in descending order — accounted for 80 percent of the total U.S. ammonia production capacity. U.S. production was estimated to be 7.7 Mt (8.5 million st) of nitrogen (N) content in 2009 compared with 7.85 Mt (8.65 million st) of N content in 2008. Apparent consumption was estimated to have decreased to 12.1 Mt (13.3 million st) of N, a 10-percent decrease from 2008. The United States was the world's fourth-ranked ammonia producer and consumer following China, India and Russia. Urea, ammonium nitrate, ammonium phosphates, nitric acid and ammonium sulfate were the major derivatives of ammonia in the United States, in descending order of importance.

  20. Nitrogen fate model for gas-phase ammonia-enhanced in situ bioventing

    International Nuclear Information System (INIS)

    Marshall, T.R.

    1995-01-01

    Subsurface bioremediation of contaminants is sometimes limited by the availability of nitrogen. Introduction of gaseous ammonia to the subsurface is a feasible and economical approach to enhance biodegradation in some environments. A gaseous nutrient source may be a practical option for sites where surface application of liquid nutrients is not possible, such as sites with shallow groundwater or sites with surface operations. A conceptual nitrogen fate model was developed to provide remediation scientists and engineers with some practical guidelines in the use of ammonia-enhanced bioventing. Ammonia supplied to the subsurface dissolves readily in soil moisture and sorbs strongly to soil particles. The ammonium ion is the preferred nutrient form of many microorganisms. Some of the ammonia will be converted to nitrate by ammonia-oxidizing organisms. Field monitoring data from an operating ammonia-enhanced bioventing remediation site for diesel fuel contamination are presented. Conservative additions of ammonia promoted appreciable increases in evolved carbon dioxide and rate of oxygen utilization. An overabundance of added ammonia promoted formation of methane from likely anaerobic hydrocarbon degradation in the presence of nitrate as the electron acceptor

  1. The roles of nematodes in nitrogen and phosphorous availability, plant uptake and growth in organically amended soils

    Science.gov (United States)

    Gebremikael, Mesfin; Buchan, David; De Neve, Stefaan

    2017-04-01

    Several studies have shown that soil biota contributes significantly to the crucial ecosystem functions and services such as organic matter decomposition and nutrient cycling. The contribution of each group of soil organisms may vary depending primarily on their feeding behavior. The magnitude of the ecosystem services by the biota may also depend on the interactions amongst the soil biota groups and their surrounding environment, for instance, biochemical characteristics of the externally added organic material. However, only a few studies considered these interactions concurrently. Here, we investigated the effects of fauna-microbe-plant interactions on organic matter decomposition and nutrient cycling by applying different organic materials spanning a range of C:N ratios and presumed N availability. Nematodes were selected as model fauna because they are the most abundant soil metazoans that have a diversified feeding strategy and interact very intimately with microbes, other fauna, and plants. A series of incubation experiments were conducted in bare and planted microcosms under controlled conditions using fresh soil collected from an agricultural field and defaunated by gamma irradiation. In the first experiment without plants, the defaunated soil cores were either left unamended (UNA) or received lignin-rich low N compost (COI), N-rich compost (COV), fresh manure (MAN) or chopped clover (CLO). The entire free-living soil nematode community was extracted from unirradiated fresh soil and reinoculated into half of the soil cores that had been defaunated by gamma irradiation. Two treatments: with (+Nem) and without (-Nem) nematodes were compared for soil nitrogen and phosphorus availability, plant uptake, and PLFA signatures over time during a 105-days incubation. The same experimental setup was used to investigate further the CLO amendment in the presence of plants (rye grass was used as a model plant). Nematodes were extracted and assigned to feeding groups

  2. Nitrogen release, tree uptake, and ecosystem retention in a mid-rotation loblolly pine plantation following fertilization with 15N-enriched enhanced efficiency fertilizers.

    OpenAIRE

    Werner, Amy

    2013-01-01

    Nitrogen is the most frequently limiting nutrient in southern pine plantations.  Previous studies found that only 10 to 25% of applied urea fertilizer N is taken up by trees.  Enhanced efficiency fertilizers could increase tree uptake efficiency by controlling the release of N and/or stabilize N.  Three enhanced efficiency fertilizers were selected as a representation of fertilizers that could be used in forestry: 1) NBPT treated urea (NBPT urea), 2) polymer coated urea (PC urea), and 3) mono...

  3. In situ carbon and nitrogen dynamics in ryegrass-clover mixtures

    DEFF Research Database (Denmark)

    Rasmussen, J.; Eriksen, J.; Jensen, Erik Steen

    2007-01-01

    =9). 15N-enriched compounds were not detected in percolating pore water, which may be caused by either dilution from irrigation or low availability of leachable N compounds. 14C was found solely as 14CO2 in the pore water indicating that dissolved organic carbon (DOC) did not originate from fresh......Carbon (C) and nitrogen (N) dynamics in a third production year ryegrass–clover mixture were investigated in the field. Cylinders (diameter 29.7 cm) were installed to depths of 20, 40 and 60 cm and equipped with suction cups to collect percolating pore water. Ryegrass and clover leaves were cross......-labelled with 14C- and 15N-enriched urea and the fate of the two tracers was studied for 3 months during summer. Transfer of 14C occurred mainly from ryegrass to clover, whereas the largest transfer of 15N was in the opposite direction. The average transfer of N from clover was 40% (SE±3.1, n=9) of N in ryegrass...

  4. No effect of NOS inhibition on skeletal muscle glucose uptake during in situ hindlimb contraction in healthy and diabetic Sprague-Dawley rats.

    Science.gov (United States)

    Hong, Yet Hoi; Betik, Andrew C; Premilovac, Dino; Dwyer, Renee M; Keske, Michelle A; Rattigan, Stephen; McConell, Glenn K

    2015-05-15

    Nitric oxide (NO) has been shown to be involved in skeletal muscle glucose uptake during contraction/exercise, especially in individuals with Type 2 diabetes (T2D). To examine the potential mechanisms, we examined the effect of local NO synthase (NOS) inhibition on muscle glucose uptake and muscle capillary blood flow during contraction in healthy and T2D rats. T2D was induced in Sprague-Dawley rats using a combined high-fat diet (23% fat wt/wt for 4 wk) and low-dose streptozotocin injections (35 mg/kg). Anesthetized animals had one hindlimb stimulated to contract in situ for 30 min (2 Hz, 0.1 ms, 35 V) with the contralateral hindlimb rested. After 10 min, the NOS inhibitor, N(G)-nitro-l-arginine methyl ester (l-NAME; 5 μM) or saline was continuously infused into the femoral artery of the contracting hindlimb until the end of contraction. Surprisingly, there was no increase in skeletal muscle NOS activity during contraction in either group. Local NOS inhibition had no effect on systemic blood pressure or muscle contraction force, but it did cause a significant attenuation of the increase in femoral artery blood flow in control and T2D rats. However, NOS inhibition did not attenuate the increase in muscle capillary recruitment during contraction in these rats. Muscle glucose uptake during contraction was significantly higher in T2D rats compared with controls but, unlike our previous findings in hooded Wistar rats, NOS inhibition had no effect on glucose uptake during contraction. In conclusion, NOS inhibition did not affect muscle glucose uptake during contraction in control or T2D Sprague-Dawley rats, and this may have been because there was no increase in NOS activity during contraction. Copyright © 2015 the American Physiological Society.

  5. Incorporation of low energy activated nitrogen onto HOPG surface: Chemical states and thermal stability studies by in-situ XPS and Raman spectroscopy

    Science.gov (United States)

    Chandran, Maneesh; Shasha, Michal; Michaelson, Shaul; Hoffman, Alon

    2016-09-01

    In this paper we report the chemical states analysis of activated nitrogen incorporated highly oriented pyrolytic graphite (HOPG) surface under well-controlled conditions. Nitrogen incorporation is carried out by two different processes: an indirect RF nitrogen plasma and low energy (1 keV) N2+ implantation. Bonding configuration, concentration and thermal stability of the incorporated nitrogen species by aforesaid processes are systematically compared by in-situ X-ray photoelectron spectroscopy (XPS). Relatively large concentration of nitrogen is incorporated onto RF nitride HOPG surface (16.2 at.%), compared to N2+ implanted HOPG surface (7.7 at.%). The evolution of N 1s components (N1, N2, N3) with annealing temperature is comprehensively discussed, which indicates that the formation and reorganization of local chemical bonding states are determined by the process of nitridation and not by the prior chemical conditioning (i.e., amorphization or hydrogenation) of the HOPG surface. A combined XPS and Raman spectroscopy studies revealed that N2+ implantation process resulted in a high level of defects to the HOPG surface, which cannot be annealed-out by heat treatment up to 1000 °C. On the other hand, the RF nitrogen plasma process did not produce a high level of surface defects, while incorporating nearly the same amount of stable nitrogen species.

  6. Simple fabrication of solid phase microextraction fiber employing nitrogen-doped ordered mesoporous polymer by in situ polymerization.

    Science.gov (United States)

    Zheng, Juan; Liang, Yeru; Liu, Shuqin; Jiang, Ruifen; Zhu, Fang; Wu, Dingcai; Ouyang, Gangfeng

    2016-01-04

    A combination of nitrogen-doped ordered mesoporous polymer (NOMP) and stainless steel wires led to highly sensitive, selective, and stable solid phase microextraction (SPME) fibers by in situ polymerization for the first time. The ordered structure of synthesized NOMP coating was illustrated by transmission electron microscopy (TEM) and X-ray diffraction (XRD), and microscopy analysis by scanning electron microscopy (SEM) confirmed a homogenous morphology of the NOMP-coated fiber. The NOMP-coated fiber was further applied for the extraction of organochlorine pesticides (OCPs) with direct-immersion solid-phase microextraction (DI-SPME) method followed by gas chromatography-mass spectrometry (GC-MS) quantification. Under the optimized conditions, low detection limits (0.023-0.77 ng L(-1)), a wide linear range (9-1500 ng L(-1)), good repeatability (3.5-8.1%, n=6) and excellent reproducibility (1.5-8.3%, n=3) were achieved. Moreover, the practical feasibility of the proposed method was evaluated by determining OCPs in environmental water samples with satisfactory recoveries. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Ultraviolet electroluminescence from nitrogen-doped ZnO-based heterojuntion light-emitting diodes prepared by remote plasma in situ atomic layer-doping technique.

    Science.gov (United States)

    Chien, Jui-Fen; Liao, Hua-Yang; Yu, Sheng-Fu; Lin, Ray-Ming; Shiojiri, Makoto; Shyue, Jing-Jong; Chen, Miin-Jang

    2013-01-23

    Remote plasma in situ atomic layer doping technique was applied to prepare an n-type nitrogen-doped ZnO (n-ZnO:N) layer upon p-type magnesium-doped GaN (p-GaN:Mg) to fabricate the n-ZnO:N/p-GaN:Mg heterojuntion light-emitting diodes. The room-temperature electroluminescence exhibits a dominant ultraviolet peak at λ ≈ 370 nm from ZnO band-edge emission and suppressed luminescence from GaN, as a result of the decrease in electron concentration in ZnO and reduced electron injection from n-ZnO:N to p-GaN:Mg because of the nitrogen incorporation. The result indicates that the in situ atomic layer doping technique is an effective approach to tailoring the electrical properties of materials in device applications.

  8. In situ synthesis of Prussian blue nanoparticles within a biocompatible reverse micellar system for in vivo Cs"+ uptake

    International Nuclear Information System (INIS)

    Lavaud, Cyril; Kajdan, Marilyn; Long, Jerome; Larionova, Joulia; Guari, Yannick; Compte, Elsa; Maurel, Jean-Claude; Him, Josephine Lai Kee; Bron, Patrick; Oliviero, Erwan

    2017-01-01

    A new highly stable Prussian blue reverse micellar system comprising ultra-small Prussian blue nanoparticles in Aonyss (Peceolt, b-sitosterol, lecithin, ethanol and water) acts as an in vivo Cs"+ uptake agent presenting higher efficiency compared to commercially available Prussian blue treatment with a significant dose effect. (authors)

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

    International Nuclear Information System (INIS)

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

    2012-09-01

    A pot experiment was conducted to study the effects of silicon (Si) and/or potassium (K) on dry matter yield, nitrogen uptake and carbon isotope discrimination Δ 13 C in water stressed (FC1) and well watered (FC2) chickpea plants using 15 N and 13 C isotopes. Three fertilizer rates of Si (Si 5 0, Si 1 00 and Si 2 00) and one fertilizer rate of K were used. The results showed that: In chickpeas, it was found, for most of the growth parameters, that Si either alone or in combination with K was more effective to alleviate water stress than K alone. Increasing soil water level from FC1 to FC2 often had a positive impact on values of most studied parameters. The Si 1 00K + (FC1) and Si 5 0K + (FC2) treatments gave high enough amounts of N 2 -fixation, higher dry matter production and greater nitrogen yield. The percent increments of total N 2 -fixed in the above mentioned treatments were 51 and 47% over their controls, respectively. On the other hand, increasing leaves dry matter in response to the solely added Si (Si 5 0K - and Si 1 00K - ) is associated with lower Δ 13 C under both watering regimes. This may indicate that Si fertilization had a beneficial effect on water use efficiency (WUE). Hence, Δ 13 C could be an adequate indicator of WUE in response to the exogenous supply of silicon to chickpea plants. Our results highlight that Si is not only involved in amelioration of growth and in maintaining of water status but it can be considered as an important element for the symbiotic performance of chickpea plants. It can be concluded that synergistic effect of silicon and potassium fertilization with adequate irrigation improves growth and nitrogen fixation in chickpea plants.In barley plants, solely added K or in combination with adequate rate of Si (Si 1 00) were more effective in alleviating water stress and producing higher yield in barley plants than solely added Si. However, the latter nutrient was found to be more effective than the former in producing

  10. Evaluation of Nitrogen Uptake and Growth Performance of Advanced Mutant Lines MR219-4 and MR219-9 Grown Under Aerobic Conditions

    International Nuclear Information System (INIS)

    Shyful Azizi Abdul Rahman; Abdul Rahim Harun; Rusli Ibrahim; Khairuddin Abdul Rahim

    2014-01-01

    Developing a good crop production management package; drought resistance variety, effective water and nutrient management in rice production practices is crucial for global climate change adaptation. A research project under IAEA RAS5065 (Supporting Climate-Proofing Rice Production Systems (CRiPS) Based on Nuclear Applications) was conducted from 2012 to 2013, in collaboration with MARDI. Two advanced mutant lines, MR219-4 and MR219-9 were used in this research project to evaluate growth, yield potential and fertilizer uptake under different water input condition (flooded and aerobic). The advanced mutant line MR219-9 showed comparable growth, yield and nitrogen uptake under both flooded and aerobic conditions. The yield and yield components are not significantly different from the parent variety (MR219) but total N uptake was lower than MR219 regardless of water regime. The field trial showed that MR219-9 has a better total N content which is comparable to the aerobic rice variety (MRIA 1) and this indicates that this advance mutant line MR219-9 is a potential aerobic rice variety. (author)

  11. Uptake of soil-, foliar-and pod-applied nitrogen and phosphorus by rape (Brassica napus L.)

    International Nuclear Information System (INIS)

    Zhang Qinzheng; Xi Haifu; Lang Xianhua

    1992-01-01

    Uptake of soil-applied and foliar-and pod applied N, P by rape was studied by using 32 P and 15 N labelled fertilizer under pot culture condition. Application of phosphorus fertilizer to purplish clayey paddy soil which was poor in available P had influence on utilization of basal-dressed NH 4 HCO 3 by rape and subsequently on its growth and seed yield. Utilization rate of applied N in whole plant and seeds were 3.66 and 5.13 fold respectively as compared with control when 187.5 kg/ha of superphosphate were applied and increased with increasing application of superphosphate (187.5-562.5 kg/ha). Application of P fertilizer not only increased uptake of N but also promoted transportation of N from vegetative organs to seeds. Rape plant uptook 69.09% of foliar-and pod-applied N in form of 2% solution of urea after flowering and transported the N to seeds in greater proportion than that of soil-applied N. In the same period, 60% of foliar- and pod-applied P in form of 0.2% KH 2 PO 4 was absorbed by rape plant, most of which was in leaves. Uptake of N and P by rape increased 17.89% and 27.78% respectively when urea and phosphate was applied together compared with using urea and phosphate alone. Uptake of basal-dressed P by rape plant was 6% at early growing stage

  12. Increased nitrogen leaching following soil freezing is due to decreased root uptake in a northern hardwood forest

    Science.gov (United States)

    John L. Campbell; Anne M. Socci; Pamela H. Templer

    2014-01-01

    The depth and duration of snow pack is declining in the northeastern United States as a result of warming air temperatures. Since snow insulates soil, a decreased snow pack can increase the frequency of soil freezing, which has been shown to have important biogeochemical implications. One of the most notable effects of soil freezing is increased inorganic nitrogen...

  13. Effects of coal combustion byproduct encapsulated ammonium nitrate on wheat yield and uptake of nitrogen and metals

    Science.gov (United States)

    Nitrogen is an essential plant nutrient that is taken up in large quantity. Ammonium nitrate (AN) is used in agriculture as an N fertilizer, but it is also an ingredient in explosives. As a result of the bombing of the Alfred P. Murrah Federal Building in Oklahoma City in April 1995, regulations o...

  14. Influence of heterogeneous ammonium availability on bacterial community structure and the expression of nitrogen fixation and ammonium transporter genes during in situ bioremediation of uranium-contaminated groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Mouser, P.J.; N' Guessan, A.L.; Elifantz, H.; Holmes, D.E.; Williams, K.H.; Wilkins, M.J.; Long, P.E.; Lovley, D.R.

    2009-04-01

    The impact of ammonium availability on microbial community structure and the physiological status and activity of Geobacter species during in situ bioremediation of uranium-contaminated groundwater was evaluated. Ammonium concentrations varied by as much as two orders of magnitude (<4 to 400 {micro}M) across the study site. Analysis of 16S rRNA gene sequences suggested that ammonium influenced the composition of the microbial community prior to acetate addition with Rhodoferax species predominating over Geobacter species at the site with the highest ammonium, and Dechloromonas species dominating at sites with lowest ammonium. However, once acetate was added, and dissimilatory metal reduction was stimulated, Geobacter species became the predominant organisms at all locations. Rates of U(VI) reduction appeared to be more related to the concentration of acetate that was delivered to each location rather than the amount of ammonium available in the groundwater. In situ mRNA transcript abundance of the nitrogen fixation gene, nifD, and the ammonium importer gene, amtB, in Geobacter species indicated that ammonium was the primary source of nitrogen during in situ uranium reduction, and that the abundance of amtB transcripts was inversely correlated to ammonium levels across all sites examined. These results suggest that nifD and amtB expression by subsurface Geobacter species are closely regulated in response to ammonium availability to ensure an adequate supply of nitrogen while conserving cell resources. Thus, quantifying nifD and amtB expression appears to be a useful approach for monitoring the nitrogen-related physiological status of Geobacter species in subsurface environments during bioremediation. This study also emphasizes the need for more detailed analysis of geochemical/physiological interactions at the field scale, in order to adequately model subsurface microbial processes.

  15. Cyanobacteria-derived nitrogen uptake by benthic invertebrates in Lake Taihu: a mesocosm study using 15N labeling

    Directory of Open Access Journals (Sweden)

    Yu J.

    2014-01-01

    Full Text Available Eutrophication of lakes can lead to dominance by cyanobacteria, which are hardly used by zooplankton due to their low nutrition value. However, sedimented cyanobacterial detritus may be a useful source for benthic invertebrates. We studied the Microcystis-derived nitrogen incorporation in benthic invertebrates in Lake Taihu using stable isotopic nitrogen (15N as a tracer. The δ15N of all organisms increased significantly with time after addition of the labeled Microcystis detritus. δ15N values of POM and periphyton peaked earlier than for benthic invertebrates, and the maximum levels were also higher than bivalves, snails and worms (Limnodrilus spp.. Among benthic invertebrates, Radix swinhoei peaked later than other invertebrates, but the maximum level and the excess 15N of the last sampling day were higher. At the end of the experiment, approximately 70% of the added 15N was retained in the benthic food web, while only a small fraction (less than 1% of the added detritus 15N occurred in the pelagic food web. Our results suggest that nitrogen from cyanobacteria can be incorporated more in benthic than pelagic food webs and cyanobacterial blooms may contribute to the development of benthic animals.

  16. Effect of different fertilization and irrigation methods on nitrogen uptake, intercepted radiation and yield of okra (Abelmoschus esculentum L.) grown in the Keta Sand Spit of Southeast Ghana

    DEFF Research Database (Denmark)

    Danso, E. Oppong; Abenney-Mickson, S.; Sabi, E.B.

    2015-01-01

    spread, (ii) irrigation by sprinkler, fertilized with localized manure, (iii) irrigation by drip, fertilized with localized manure, (iv) irrigation by drip, fertigated with N-K chemical fertilizers (twice during the crop season in the first experiment, weekly in the second and third experiment). Nitrogen...... uptake, crop interception of solar radiation, yield and water productivity were compared among treatments. The crop did not respond well when fertigation was done only twice, probably due to N-leaching. However, in the second and third experiments, when fertigation was done weekly for eight weeks......Three seasons' experiments were conducted in the Keta Sand Spit to test if current use of sprinkler irrigation and animal manure can be substituted by water saving drip fertigation with reduced P supply to okra. The treatments compared were: (i) irrigation by sprinkler, fertilized with manure...

  17. Influence of trophic level, and calcification on the uptake of plutonium observed, in situ, in marine organisms

    International Nuclear Information System (INIS)

    Guary, J.C.; Fraizier, A.

    1977-01-01

    A study has been made of the transport mechanisms of plutonium in the marine environment. This work has shown that a relationship exists between the concentration of plutonium in marine plant and animal species and the trophic level of these organisms; this relation is evidenced by a decrease in the concentration of the radioelement as the trophic level of the species increases. Three modes of transport - via water, sediment and food - have been studied. Direct contact between sea water and organisms, the principal mode of transfer to marine species belonging to lower trophic levels (the primary producers and consumers), seems to play an important role in the uptake of plutonium. On the other hand, the sediment in contact with which certain species live does not appear to constitute an important transfer vector. The trophic relations between animal species lead one to assume that plutonium is transported also via the food-chain without necessarily implying that there is a concentration of the radioelement along the whole chain leading from the primary producers to the tertiary consumers. In addition, it has been possible to establish that there is a relation between the rate of plutonium uptake and the calcified structures of certain marine species comparable to that which exists in the bone tissue of terrestrial mammals. (author)

  18. Quantifying biological nitrogen fixation of different catch crops, and residual effects of roots and tops on nitrogen uptake in barley using in-situ 15N labelling

    DEFF Research Database (Denmark)

    Li, Xiaoxi; Sørensen, Peter; Li, F C

    2015-01-01

    –46 % in macro-roots (0–18 cm soil). Macro-roots represented 31–50 % of total plant N. LBCCs showed similar capacity for soil N extraction as non-LBCCs. After incorporation of LBCC residues, the dry matter and N yields of spring barley were comparable to the effect of 50 kg N fertilisation ha−1, whereas no extra...

  19. In situ one-step synthesis of hierarchical nitrogen-doped porous carbon for high-performance supercapacitors.

    Science.gov (United States)

    Jeon, Ju-Won; Sharma, Ronish; Meduri, Praveen; Arey, Bruce W; Schaef, Herbert T; Lutkenhaus, Jodie L; Lemmon, John P; Thallapally, Praveen K; Nandasiri, Manjula I; McGrail, Benard Peter; Nune, Satish K

    2014-05-28

    A hierarchically structured nitrogen-doped porous carbon is prepared from a nitrogen-containing isoreticular metal-organic framework (IRMOF-3) using a self-sacrificial templating method. IRMOF-3 itself provides the carbon and nitrogen content as well as the porous structure. For high carbonization temperatures (950 °C), the carbonized MOF required no further purification steps, thus eliminating the need for solvents or acid. Nitrogen content and surface area are easily controlled by the carbonization temperature. The nitrogen content decreases from 7 to 3.3 at % as carbonization temperature increases from 600 to 950 °C. There is a distinct trade-off between nitrogen content, porosity, and defects in the carbon structure. Carbonized IRMOFs are evaluated as supercapacitor electrodes. For a carbonization temperature of 950 °C, the nitrogen-doped porous carbon has an exceptionally high capacitance of 239 F g(-1). In comparison, an analogous nitrogen-free carbon bears a low capacitance of 24 F g(-1), demonstrating the importance of nitrogen dopants in the charge storage process. The route is scalable in that multi-gram quantities of nitrogen-doped porous carbons are easily produced.

  20. Effects of shading on photosynthesis, plant organic nitrogen uptake and root fungal colonization in a subarctic mire ecosystem

    DEFF Research Database (Denmark)

    Olsrud, Hanna Maria Kerstin; Michelsen, Anders

    2009-01-01

    Arctic dwarf shrub ecosystems are predicted to be exposed to lower light intensity in a changing climate where mountain birch forests are expanding. We investigated how shading at 0%, 65%, and 97% affects photosynthesis, organic N uptake, C and N allocation patterns in plants, and root fungal...... ecosystems are capable of taking up organic N as intact glycine both under high irradiance levels and under shaded conditions when photosynthesis is strongly reduced. The allocation of 15N to green leaves of Rubus chamaemorus L. increased with shading, whereas the allocation of 13C to leaves of both...

  1. Gibberellin Is Involved in Inhibition of Cucumber Growth and Nitrogen Uptake at Suboptimal Root-Zone Temperatures.

    Directory of Open Access Journals (Sweden)

    Longqiang Bai

    Full Text Available Suboptimal temperature stress often causes heavy yield losses of vegetables by suppressing plant growth during winter and early spring. Gibberellin acid (GA has been reported to be involved in plant growth and acquisition of mineral nutrients. However, no studies have evaluated the role of GA in the regulation of growth and nutrient acquisition by vegetables under conditions of suboptimal temperatures in greenhouse. Here, we investigated the roles of GA in the regulation of growth and nitrate acquisition of cucumber (Cucumis sativus L. plants under conditions of short-term suboptimal root-zone temperatures (Tr. Exposure of cucumber seedlings to a Tr of 16°C led to a significant reduction in root growth, and this inhibitory effect was reversed by exogenous application of GA. Expression patterns of several genes encoding key enzymes in GA metabolism were altered by suboptimal Tr treatment, and endogenous GA concentrations in cucumber roots were significantly reduced by exposure of cucumber plants to 16°C Tr, suggesting that inhibition of root growth by suboptimal Tr may result from disruption of endogenous GA homeostasis. To further explore the mechanism underlying the GA-dependent cucumber growth under suboptimal Tr, we studied the effect of suboptimal Tr and GA on nitrate uptake, and found that exposure of cucumber seedlings to 16°C Tr led to a significant reduction in nitrate uptake rate, and exogenous application GA can alleviate the down-regulation by up regulating the expression of genes associated with nitrate uptake. Finally, we demonstrated that N accumulation in cucumber seedlings under suboptimal Tr conditions was improved by exogenous application of GA due probably to both enhanced root growth and nitrate absorption activity. These results indicate that a reduction in endogenous GA concentrations in roots due to down-regulation of GA biosynthesis at transcriptional level may be a key event to underpin the suboptimal Tr

  2. Uptake and distribution of combined nitrogen and its incorporation into seeds of nodulated soybean plants as revealed by 15N studies

    International Nuclear Information System (INIS)

    Rabie, R.K.; Arima, Yasuhiro; Kumazawa, Kikuo

    1980-01-01

    Pot experiments were carried out with soybean plants grown with N-free solution, then supplied with NO 3 - or NH 4 + before 15 N administration, in order to study the uptake, distribution and redistribution of absorbed nitrogen. To determine the utilization and incorporation of combined nitrogen to the yield of seeds, as influenced by the form of N and application time, another series of experiments was carried out, in which the plants were grown with N-free solution, then 15 N was fed as 15 NO 3 - or 15 NH 4 + at pod setting stage (PS) or initial pod filling stage (IPF). By comparing the nitrate-treated plants (Nt plants) with the ammonia-treated ones (Am plants), and the treatment at PS with that at IPF, the following results were obtained. Nt plants accumulated larger amount of dry matters in respective plant parts than Am plants, particularly in the pods, and it was proved that the pods were the active sinks for newly metabolized nitrate. Both 15 N abundance and 15 N incorporation in the whole plants were much higher in Nt plants, and those in respective plant parts except nodules were also higher in Nt plants. Large part of the 15 N in roots was redistributed to the top parts in Nt plants, while large part of the absorbed N was distributed to the nodules in Am plants. Some more results are reported. (Kako, I.)

  3. Effects of Two Soil Amendments from Steel Slag on Rice Growth and Nitrogen, Phosphorus and Potassium Uptake

    Directory of Open Access Journals (Sweden)

    ZHANG Lu

    2017-08-01

    Full Text Available A pot experiment was conducted to investigate the effects of two soil amendments(W and Y derived from steel slag and their application rates(0.74, 1.47, 2.94, 5.88 g·kg-1 and 11.76 g·kg-1 for W; 1.47, 2.94, 5.88, 11.76 g·kg-1 and 23.52 g·kg-1 for Y on rice growth. The results showed that no significant change in rice yield was found following W amendments; conversely, a 20% increase in rice yield was observed following Y amendments at rates of 11.76 g·kg-1 and 23.52 g·kg-1 as compared with NPK treatments. Y amendment at rates of 5.88~23.52 g·kg-1 increased straw mass by 24.02%~35.23% when compared with NPK treatments. Combined application of Y amendments and NPK fertilizers increased subsequent N, P and K uptake by rice by 12.61%~21.55%, 7.63%~38.31% and 11.89%~54.13%, respectively. The results indicated Y amendments could effectively accelerate subsequent rice growth at high application rates by increasing nutrient uptake in the soil studied(pH 6.51; Conversely, we observed no significant effects with W amendments.

  4. In situ experiments to determine the uptake of copper by the aquatic macrophyte Najas tenuifolia R.Br

    International Nuclear Information System (INIS)

    Hart, B.T.; Jones, M.J.; Breen, P.

    1984-01-01

    In situ experiments, in which ionic copper was added to an enclosed area of the aquatic macrophyte Najas tenuifolia R.Br., showed that this plant can rapidly (in around six hours) take up considerable amounts of the added copper. Epiphytes (and their associated microfauna) present on this macrophyte took up the added copper even more rapidly, but also seemed to release the copper equally fast. At the end of the three day experiment 30% to 60% of the added copper was associated with the macrophytes and 15% to 20% was still in the water column. The remainder of the copper was associated with the 'epiphyte component', the sediments and probably also the walls of the plastic enclosure

  5. Long-term population dynamics and in situ physiology in activated sludge systems with enhanced biological phosphorus removal operated with and without nitrogen removal

    DEFF Research Database (Denmark)

    Lee, N.; Nielsen, P.H.; Aspegren, H.

    2003-01-01

    . However, we observed a lower correlation (0.9). The Actinobacteria were the only additional group of bacteria which showed a similar degree of correlation to the P content in activated sludge as the Rhodocyclus-related bacteria - but only for the system without nitrogen removal. Significant amounts (less...... of the Betaproteobacteria (part of them identified as Rhodocyclus-related bacteria) as well as the Actinobacteria were able to take up P-33(i), [H-3]-acetate and [H-3]-glucose under anaerobic-aerobic conditions. The contribution of anoxic P-33(i) uptake under alternating anaerobic-anoxic conditions was significantly lower...

  6. Evaluation of Vermicompost and Nitrogen Biofertilizer Effects on Flowering Shoot Yield, Essential Oil and Mineral Uptake (N, P and K in Summer Savory (Satureja hortensis L.

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Haj Seyed Hadi

    2018-02-01

    (2.01% were obtained by using 10 ton per hectare of vermicompost. Applying 15 ton per hectare of vermicompost caused maximum flowering shoot yield (2237.82kg/ha, nitrogen (2.21% and phosphorus (0.52% content in the aboveground shoot. Mean comparison indicated that seed inoculation with Supernitroplus had significant effects on all measured traits except for nitrogen content in aboveground shoot. The maximum fresh and dry plant weight (40.21 and 14.42g/plant, flowering shoot yield (2406.21kg/ha, essential oil (2.05%, phosphorus (0.49% and potassium (1.34% were obtained by applying Supernitroplus. The maximum nitrogen content (2.23% was obtained by using Nitroxine. Results of interaction effects showed that using supernitroplus and 15 ton per hectare of vermicompost caused maximum potassium content (1.50% in Savory shoots. Several types of studies have shown a beneficial effect on crop plants by inoculation of seeds with Azospirillum and Azotobacter strains. Inoculation of plants with Azospirillum and Azotobacter can results in significant changes in various plant growth parameters. Positive effects of inoculation have been demonstrated on including increase in root length and nutrition (NO3- , NH4+, P042- , K +, Rb+ and Fe++ uptake. Nitrogen and phosphorus are the two major plant nutrients and combined inoculation of nitrogen fixers and PSM may benefit the plants better than either group of organisms alone. Interaction studies have been done both in vitro and in vivo. Nitrogen fixers and PSM when inoculated together colonized the rhizosphere and enhanced the growth of crops by providing it with nitrogen and phosphate, respectively. Vermicompost contains most of the plant nutrients such as nitrate, phosphates, exchangeable calcium and soluble potassium, and microelements which result in improved plant growth and development and is responsible for increased qualitative and quantitative yield of many crops. Conclusion The results of current experiment showed that

  7. Effects of inorganic nitrogen form on growth, morphology, N uptake, and nutrient allocation in hybrid Napier grass (Pennisetum purpureum × Pennisetum americanum cv. Pakchong1)

    DEFF Research Database (Denmark)

    Jampeetong, Arunothai; Brix, Hans; Kantawanichkul, Suwasa

    2014-01-01

    in such systems. We studied the effects of inorganic nitrogen form (NH4 +, NH4NO3 or NO3 -) on growth, morphology, N uptake, water content and mineral allocation in this species under hydroponic conditions at equimolar concentrations (500μmolNL-1). Generally, the N-form significantly affected growth, biomass...

  8. The Arabidopsis Halophytic Relative Thellungiella halophila Tolerates Nitrogen-Limiting Conditions by Maintaining Growth, Nitrogen Uptake, and Assimilation1[W][OA

    Science.gov (United States)

    Kant, Surya; Bi, Yong-Mei; Weretilnyk, Elizabeth; Barak, Simon; Rothstein, Steven J.

    2008-01-01

    A comprehensive knowledge of mechanisms regulating nitrogen (N) use efficiency is required to reduce excessive input of N fertilizers while maintaining acceptable crop yields under limited N supply. Studying plant species that are naturally adapted to low N conditions could facilitate the identification of novel regulatory genes conferring better N use efficiency. Here, we show that Thellungiella halophila, a halophytic relative of Arabidopsis (Arabidopsis thaliana), grows better than Arabidopsis under moderate (1 mm nitrate) and severe (0.4 mm nitrate) N-limiting conditions. Thellungiella exhibited a lower carbon to N ratio than Arabidopsis under N limitation, which was due to Thellungiella plants possessing higher N content, total amino acids, total soluble protein, and lower starch content compared with Arabidopsis. Furthermore, Thellungiella had higher amounts of several metabolites, such as soluble sugars and organic acids, under N-sufficient conditions (4 mm nitrate). Nitrate reductase activity and NR2 gene expression in Thellungiella displayed less of a reduction in response to N limitation than in Arabidopsis. Thellungiella shoot GS1 expression was more induced by low N than in Arabidopsis, while in roots, Thellungiella GS2 expression was maintained under N limitation but was decreased in Arabidopsis. Up-regulation of NRT2.1 and NRT3.1 expression was higher and repression of NRT1.1 was lower in Thellungiella roots under N-limiting conditions compared with Arabidopsis. Differential transporter gene expression was correlated with higher nitrate influx in Thellungiella at low 15NO3− supply. Taken together, our results suggest that Thellungiella is tolerant to N-limited conditions and could act as a model system to unravel the mechanisms for low N tolerance. PMID:18467466

  9. Identification and analysis of hydrogen uptake (HUP) genes of several associative nitrogen fixing bacteria with rice plant

    International Nuclear Information System (INIS)

    Yuan Hongli; Wang Huixian; You Chongbiao

    1990-01-01

    All of the tested species (strains) in this work can reduce TTC, suggesting that they contain hydrogen uptake hydrogenase. Hybridization with Rhizobium japonicum hup gene indicated that there was homology between restricted DNA and the probe for Alcaligenes faecalis A15, Enterobacter cloacae EnSs, Klebsiella planticola DWUL2 and Pseudomonas saccharophila. Negative results were obtained for E. cloacae E26 and K. oxytoca NG13. Hup genes of A. faecalis A15 were located on chromosomal DNA, however, it was located on the larger plasmid for E. cloacae EnSs. Nif gene and hup gene are located on the same replicon. Hup gene from different hup + microorganisms was not homology inevitably

  10. Physiological responses by juvenile Egregia menziesii (Phaeophyta) to simulated effects of wave action: Carbon and nitrogen uptake and carbon partitioning

    International Nuclear Information System (INIS)

    Kraemer, G.P.

    1990-01-01

    Although biomechanical and morphological adaptations to different wave energy regimes are well known, the physiological mechanisms behind, and the trigger(s) eliciting these responses, are not. Egregia menziesii (Turn.) Aresch. juveniles (5-10 cm) were incubated for 4 hr in chambers containing 14 C-labeled bicarbonate, under combinations of two levels of nutrient concentration and two levels of tensile force. Whole tissue and cell wall material (=cellulose + alginates) were examined for 14 C incorporation. Tensile force elicited greater incorporation into whole tissue and directed more carbon into the cell wall compartment. Ambient nutrient levels and tissue age both had inverse effects on carbon partitioning into cell wall material. Tensile force also reduced nitrate uptake rates by about 50%

  11. Nitrogen budget of the northwestern Black Sea shelf inferred from modeling studies and in situ benthic measurements

    NARCIS (Netherlands)

    Grégoire, M.; Friedrich, J.

    2004-01-01

    A 3D eddy-resolving coupled biogeochemical-hydrodynamical model and in situ observations are used to investigate benthic processes on the Black Sea's NW shelf. Measurements of benthic fluxes (oxygen, nutrients, redox compounds) with in situ flux chambers are analyzed in regard to sediment dynamics

  12. In Situ One-Step Synthesis of Hierarchical Nitrogen-Doped Porous Carbon for High Performance Supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Ju Won [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Texas A & M Univ., College Station, TX (United States); Sharma, Ronish [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Meduri, Praveen [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Arey, Bruce W. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Schaef, Herbert T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lutkenhaus, Jodie [Texas A & M Univ., College Station, TX (United States); Lemmon, John P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Thallapally, Praveen K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Nandasiri, Manjula I. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McGrail, B. Peter [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Nune, Satish K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-04-30

    Electrochemical performance of the existing state-of-the art capacitors is not very high, key scientific barrier is that its charge storage mechanism wholly depends on adsorption of electrolyte on electrode. We present a novel method for the synthesis of nitrogen -doped porous carbons and address the drawback by precisely controlling composition and surface area. Nitrogen-doped porous carbon was synthesized using a self-sacrificial template technique without any additional nitrogen and carbon sources. They exhibited exceptionally high capacitance (239 Fg-1) due to additional pseudocapacitance originating from doped nitrogen. Cycling tests showed no obvious capacitance decay even after 10,000 cycles, which meets the requirement of commercial supercapacitors. Our method is simple and highly efficient for the production of large quantities of nitrogen-doped porous carbons.

  13. Acid-promoted Bicyclization of Diaryl Alkynes: Synthesis of 2H-Indazoles with in situ Generated Diazonium Salt as Nitrogen Source.

    Science.gov (United States)

    Zhang, Cheng; Chang, Sailan; Dong, Shanliang; Qiu, Lihua; Xu, Xinfang

    2018-06-08

    An unprecedented transition-metal-free tandem bicyclization of diaryl alkynes has been disclosed, which provides a streamlined access to a range of polycyclic 2H-indazoles in high to excellent yields. The salient features of this reaction include readily available starting materials, good functional group compatibility, mild reaction conditions, no column chromatography, high bond-formation efficiency, and ease in further transformations. Notably, this is the first example for the synthesis of 2H-indazoles with in situ generated diazonium salt as the nitrogen source, and a mechanistic rationale involving an acid-promoted tandem diazonium salt formation/bicyclization process is discussed.

  14. Effects of elevated CO2 on soil organic matter turnover and plant nitrogen uptake: First results from a dual labeling mesocosm experiment

    Science.gov (United States)

    Eder, Lucia Muriel; Weber, Enrico; Schrumpf, Marion; Zaehle, Sönke

    2017-04-01

    The response of plant growth to elevated concentrations of CO2 (eCO2) is often constrained by plant nitrogen (N) uptake. To overcome potential N limitation, plants may invest photosynthetically fixed carbon (C) into N acquiring strategies, including fine root biomass, root exudation, or C allocation to mycorrhizal fungi. In turn, these strategies may affect the decomposition of soil organic matter, leading to uncertainties in net effects of eCO2 on C storage. To gain more insight into these plant-soil C-N-interactions, we combined C and N stable isotope labeling in a mesocosm experiment. Saplings of Fagus sylvatica L. were exposed to a 13CO2 enriched atmosphere at near ambient (380 ppm) or elevated (550 ppm) CO2 concentrations for four months of the vegetation period in 2016. Aboveground and belowground net CO2 fluxes were measured separately and the 13C label enabled partitioning of total soil CO2 efflux into old, soil derived and new, plant-derived C. We used ingrowth cores to assess effects of eCO2on belowground C allocation and plant N uptake in more detail and in particular we evaluated the relative importance of ectomycorrhizal associations. In the soil of each sapling, ingrowth cores with different mesh sizes allowed fine roots or only mycorrhizal hyphae to penetrate. In one type of ingrowth core each, we incorporated fine root litter that was enriched in 15N. Additionally, total N uptake was estimated by using 15N enriched saplings and unlabeled control plants. We found that eCO2 increased aboveground net CO2 exchange rates by 19% and total soil respiration by 11%. The eCO2 effect for GPP and also for NPP was positive (+23% and +11%, respectively). By combining gaseous C fluxes with data on new and old C stocks in bulk soil and plants through destructive harvesting in late autumn 2016, we will be able to infer net effects of eCO2 on the fate of C in these mesocosms. Biomass allocation patterns can reveal physiological responses to high C availability under

  15. Synergistic effects and optimization of nitrogen and phosphorus concentrations on the growth and nutrient uptake of a freshwater Chlorella vulgaris.

    Science.gov (United States)

    Alketife, Ahmed M; Judd, Simon; Znad, Hussein

    2017-01-01

    The synergistic effects and optimization of nitrogen (N) and phosphorus (P) concentrations on the growth of Chlorella vulgaris (CCAP 211/11B, CS-42) and nutrient removal have been investigated under different concentrations of N (0-56 mg/L) and P (0-19 mg/L). The study showed that N/P ratio has a crucial effect on the biomass growth and nutrient removal. When N/P=10, a complete P and N removal was achieved at the end of cultivation with specific growth rate (SGR) of 1 d -1 and biomass concentration of 1.58 g/L. It was also observed that when the N content <2.5 mg/L, the SGR significantly reduced from 1.04 to 0.23 d -1 and the maximum biomass produced was decreased more than three-fold to 0.5 g/L. The Box-Behnken experimental design and response surface method were used to study the effects of the initial concentrations (P, N and C) on P and N removal efficiencies. The optimized P, N and C concentrations supporting 100% removal of both P and N at an SGR of 0.95 were 7, 55 and 10 mg/L respectively, with desirability value of 0.94. The results and analysis obtained could be very useful when applying the microalgae for efficient wastewater treatment and nutrient removal.

  16. Using stable isotopes of carbon and nitrogen as in-situ tracers for monitoring the natural attenuation of explosives

    National Research Council Canada - National Science Library

    Miyares, Paul H

    1999-01-01

    The use of carbon and nitrogen stable isotope measurements from TNT was examined as a possible tool for monitoring the natural attenuation of TNT incubation studies of spiked soil samples were conducted...

  17. Nitrogen, phosphor, and potassium nutrients uptake of soybean (Glycine max (L.) Merril) on three levels of radiation intensities and soil moisture content of latosol

    International Nuclear Information System (INIS)

    Syahbuddin, H.; Apriyana, Y.; Heryani, N.; Darmijati, S.; Las, I.

    1998-01-01

    An experiment was implemented from July to August 1994 in greenhouse of the Ecophysiology Division, Bogor Research Institute for Food Crops using a split-split plot design with three replications. Radiation intensity levels as main plot were: without shelter, 25 percent shelter, and 67 percent shelter. Levels of available water in soil as sub-plot were: less than 25 percent soil water availability, content of soil water availability, and 125 percent soil water availability. Soybean varieties as sub-sub plots were: Wilis, Malabar, and Lokon. The experiment showed that nitrogen and phosphor uptake of Wilis was the highest, 41.228 mg and 1.225 mg per hill, especially under 100 percent light intensity and soil water availability more than 25 percent. Under 25 percent shade the potassium uptake of Wilis was 45.997 mg, this was higher than Malabar. The highest increased in seed dry weight, up to 0.733 g, occurred if soil water content changed from available water to 125 percent water content. One calory decreased in radiation caused 0.006 g decreased in seed dry weight per hill, Malabar variety produced an average of 0.892 g seed dry weight, where each millimeter of water will increased 2.0 mg of dry seed weight. Malabar variety had water use efficiency of 0.043 percent g/ml and radiation use efficiency 0.011 percent g/cal. Malabar variety produced the heaviest 100 good seed (7.293 g), followed by Wilis variety (5.520 g) and Lokon variety (4.597 g) [in

  18. Effect of in situ soil amendments on arsenic uptake in successive harvests of ryegrass (Lolium perenne cv Elka) grown in amended As-polluted soils

    International Nuclear Information System (INIS)

    Hartley, William; Lepp, Nicholas W.

    2008-01-01

    Several iron-bearing additives, selected for their potential ability to adsorb anions, were evaluated for their effectiveness in attenuation of arsenic (As) in three soils with different sources of contamination. Amendments used were lime, goethite (α-FeOOH) (crystallised iron oxide) and three iron-bearing additives, iron grit, Fe II and Fe III sulphates plus lime, applied at 1% w/w. Sequential extraction schemes conducted on amended soils determined As, Cu, Zn and Ni fractionation. Plant growth trials using perennial ryegrass (Lolium perenne var. Elka) assessed shoot As uptake. This was grown in the contaminated soils for 4 months, during which time grass shoots were successively harvested every 3 weeks. Goethite increased biomass yields, but clear differences were observed in As transfer rates with the various iron oxides. In conclusion, whilst Fe-oxides may be effective in situ amendments, reducing As bioavailability, their effects on plant growth require careful consideration. Soil-plant transfer of As was not completely halted by any amendment. - Arsenic attenuation is illustrated using Fe-based amendments, their efficacy providing different indicators of success

  19. Zinc, iron, manganese and copper uptake requirement in response to nitrogen supply and the increased grain yield of summer maize.

    Directory of Open Access Journals (Sweden)

    Yanfang Xue

    Full Text Available The relationships between grain yields and whole-plant accumulation of micronutrients such as zinc (Zn, iron (Fe, manganese (Mn and copper (Cu in maize (Zea mays L. were investigated by studying their reciprocal internal efficiencies (RIEs, g of micronutrient requirement in plant dry matter per Mg of grain. Field experiments were conducted from 2008 to 2011 in North China to evaluate RIEs and shoot micronutrient accumulation dynamics during different growth stages under different yield and nitrogen (N levels. Fe, Mn and Cu RIEs (average 64.4, 18.1 and 5.3 g, respectively were less affected by the yield and N levels. ZnRIE increased by 15% with an increased N supply but decreased from 36.3 to 18.0 g with increasing yield. The effect of cultivars on ZnRIE was similar to that of yield ranges. The substantial decrease in ZnRIE may be attributed to an increased Zn harvest index (from 41% to 60% and decreased Zn concentrations in straw (a 56% decrease and grain (decreased from 16.9 to 12.2 mg kg-1 rather than greater shoot Zn accumulation. Shoot Fe, Mn and Cu accumulation at maturity tended to increase but the proportions of pre-silking shoot Fe, Cu and Zn accumulation consistently decreased (from 95% to 59%, 90% to 71% and 91% to 66%, respectively. The decrease indicated the high reproductive-stage demands for Fe, Zn and Cu with the increasing yields. Optimized N supply achieved the highest yield and tended to increase grain concentrations of micronutrients compared to no or lower N supply. Excessive N supply did not result in any increases in yield or micronutrient nutrition for shoot or grain. These results indicate that optimized N management may be an economical method of improving micronutrient concentrations in maize grain with higher grain yield.

  20. Facile Synthesis of In–Situ Nitrogenated Graphene Decorated by Few–Layer MoS2 for Hydrogen Evolution Reaction

    International Nuclear Information System (INIS)

    Dai, Xiaoping; Li, Zhanzhao; Du, Kangli; Sun, Hui; Yang, Ying; Zhang, Xin; Ma, Xingyu; Wang, Jie

    2015-01-01

    Graphical abstract: In–situ nitrogenated graphene–few layer MoS 2 composites are fabricated by combinating chemical and hydrothermal reduction. The resulting MoS 2 /N–rGO–HA by N 2 H 4 ·H 2 O and NH 3 ·H 2 O as co-reductant exhibits high activity and remarkable stability for hydrogen evolution reaction (HER). The excellent electro-catalytic performance is ascribed to the synergistic effects, confinement effects and highly dispersed MoS 2 nanosheets on N-doping rGO. Display Omitted -- Highlights: • In–situ nitrogenated graphene–few layer MoS 2 composites are fabricated by combinating chemical and hydrothermal co-reduction. • The resulting MoS 2 /N–rGO–HA exhibits high activity and remarkable stability for HER. • The excellent electro-catalytic performance is ascribed to the synergistic effects, confinement effects and highly dispersed MoS 2 nanosheets on N-doping rGO. -- Abstract: A facile one–step synthetic strategy by combinating chemical and hydrothermal reduction of graphene oxide and Mo precursor is proposed to fabricate in–situ nitrogenated graphene–few layer MoS 2 composite (MoS 2 /N–rGO–HA) for hydrogen evolution reaction (HER). The N–doping graphene nanosheets and highly dispersed MoS 2 nanosheets by ammonia and hydrozine as co–reductant have greatly promoted the N content, concentrations of pyridinic and graphitic N, the electron transport in electrodes, and assure high catalytic efficiency. The MoS 2 /N–rGO–HA composite exhibits extremely high activity in acidic solutions with a small onset potential of 100 mV and Tafel slope of 45 mV/dec, as well as a current density about 32.4 mA cm −2 at overpotential about 0.2 V. Moreover, such MoS 2 /N–rGO–HA electroncatalyst also shows an excellent stability during 1000 cycles with negligible loss of the cathodic current. This facile hydrothermal method could provide a promising strategy for the synthesis of in–situ nitrogen–doping graphene sheets and few

  1. Anthropogenic nitrogen input traced by means of {delta} {sup 15}N values in macroalgae: Results from in-situ incubation experiments

    Energy Technology Data Exchange (ETDEWEB)

    Deutsch, Barbara [Baltic Sea Research Institute, Seestr. 15, 18119 Rostock (Germany)]. E-mail: barbara.deutsch@io-warnemuende.de; Voss, Maren [Baltic Sea Research Institute, Seestr. 15, 18119 Rostock (Germany)

    2006-08-01

    The macroalgae species Fucus vesiculosus (Phaeophyta), Polysiphonia sp., and Ceramium rubrum (Rhodophyta) originally grown at an unpolluted brackish site of the southern Baltic Sea were incubated for 10 and 14 days at 12 stations along a salinity gradient in a highly polluted estuary. We have expected an adaptation of the initially low {delta} {sup 15}N values to the higher ones within the incubation period. In addition to the macroalgae the {delta} {sup 15}N values of NO{sub 3} {sup -} were measured to evaluate fractionation processes of the source nitrate. Inside the estuary, {delta} {sup 15}N-NO{sub 3} {sup -} values were 6.2-9.7 per mille , indicating anthropogenic nitrogen sources. The red macroalgae adequately reflected the nitrate isotope values in the surrounding waters, whereas for F. vesiculosus the results were not that clear. The reasons were assumed to be higher initial {delta} {sup 15}N values of F. vesiculosus and presumably a too slow nitrogen uptake and growth rate. The method of macroalgae incubations seems suitable as a simple monitoring to study the influence of anthropogenic nitrogen loading in an estuarine environment.

  2. pOsNAR2.1:OsNAR2.1 expression enhances nitrogen uptake efficiency and grain yield in transgenic rice plants.

    Science.gov (United States)

    Chen, Jingguang; Fan, Xiaoru; Qian, Kaiyun; Zhang, Yong; Song, Miaoquan; Liu, Yu; Xu, Guohua; Fan, Xiaorong

    2017-10-01

    The nitrate (NO3-) transporter has been selected as an important gene maker in the process of environmental adoption in rice cultivars. In this work, we transferred another native OsNAR2.1 promoter with driving OsNAR2.1 gene into rice plants. The transgenic lines with exogenous pOsNAR2.1:OsNAR2.1 constructs showed enhanced OsNAR2.1 expression level, compared with wild type (WT), and 15 N influx in roots increased 21%-32% in response to 0.2 mm and 2.5 mm 15NO3- and 1.25 mm 15 NH 4 15 NO 3 . Under these three N conditions, the biomass of the pOsNAR2.1:OsNAR2.1 transgenic lines increased 143%, 129% and 51%, and total N content increased 161%, 242% and 69%, respectively, compared to WT. Furthermore in field experiments we found the grain yield, agricultural nitrogen use efficiency (ANUE), and dry matter transfer of pOsNAR2.1:OsNAR2.1 plants increased by about 21%, 22% and 21%, compared to WT. We also compared the phenotypes of pOsNAR2.1:OsNAR2.1 and pOsNAR2.1:OsNRT2.1 transgenic lines in the field, found that postanthesis N uptake differed significantly between them, and in comparison with the WT. Postanthesis N uptake (PANU) increased approximately 39% and 85%, in the pOsNAR2.1:OsNAR2.1 and pOsNAR2.1:OsNRT2.1 transgenic lines, respectively, possibly because OsNRT2.1 expression was less in the pOsNAR2.1:OsNAR2.1 lines than in the pOsNAR2.1:OsNRT2.1 lines during the late growth stage. These results show that rice NO 3 - uptake, yield and NUE were improved by increased OsNAR2.1 expression via its native promoter. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  3. Uptake and distribution of nitrogen from acidic fog within a ponderosa pine (Pinus ponderosa Laws.)/litter/soil system

    Energy Technology Data Exchange (ETDEWEB)

    Fenn, M.E.; Leininger, T.D.

    1995-11-01

    The magnitude and importance of wet deposition of N in forests of the South Coast (Los Angeles) Air Basin have not been well characterized. We exposed 3-yr-old ponderosa pine (Pinus ponderosa Laws.) seedlings growing in native forest soil to acidic fog treatments (pH 3.1) simulating fog chemistry from a pine forest near Los Angeles, California. Fog solutions contained either {sup 15}NH{sub 4}{sup +}, {sup 15}NO{sub 3}{sup {minus}}, or unlabeled N. The fog treatments were applied in open-top chambers in six 5-hr exposures. Soil treatments within each of the fog exposures were bare soil, soil overlain with L- and F-litter, and soil covered with plastic during the fog events to prevent fogwater from contacting soil. Seedlings were harvested and samples were collected 15 wk after the fog treatments. Uptake of {sup 15}N by roots was by far the dominant pathway for plant assimilation of fog-deposited {sup 15}N. Deposition of N in fog supplied 9.4% and 8.7% of the total N in current-year crown biomass in the litter-overlay and bare-soil treatments, respectively. Total N concentrations in every plant fraction except current-year stems were significantly higher in the bare-soil treatment than in the plastic-covered soil treatment. Less than 5% of the {sup 15}N deposited directly to the seedling crowns was retained by the plants in the covered-soil treatment, whereas 57% of the {sup 15}N deposited to the seedling/litter/soil systems was incorporated into plant biomass. The litter layers retained {sup 15}NH{sub 4}{sup +} more effectively than {sup 15}NH{sub 4}{sup +} more effectively than {sup 15}NO{sub 3}. Data from this study suggest that N deposited from fog may be an important source of N for plant growth in forests of the SCAB where fog occurrence and pollution exposure coincide. 5 refs., 5 figs., 3 tabs.

  4. Flexible nanohybrid microelectrode based on carbon fiber wrapped by gold nanoparticles decorated nitrogen doped carbon nanotube arrays: In situ electrochemical detection in live cancer cells.

    Science.gov (United States)

    Zhang, Yan; Xiao, Jian; Sun, Yimin; Wang, Lu; Dong, Xulin; Ren, Jinghua; He, Wenshan; Xiao, Fei

    2018-02-15

    The rapidly growing demand for in situ real-time monitoring of chemical information in vitro and in vivo has attracted tremendous research efforts into the design and construction of high-performance biosensor devices. Herein, we develop a new type of flexible nanohybrid microelectrode based on carbon fiber wrapped by gold nanoparticles decorated nitrogen-doped carbon nanotube arrays, and explore its practical application in in situ electrochemical detection of cancer biomarker H 2 O 2 secreted from live cancer cells. Our results demonstrate that carbon fiber material with microscale size and fascinating mechanical properties can be used as a robust and flexible microelectrode substrate in the electrochemical biosensor system. And the highly ordered nitrogen-doped carbon nanotube arrays that grown on carbon fiber possess high surface area-to-volume ratio and abundant active sites, which facilitate the loading of high-density and uniformly dispersed gold nanoparticles on it. Benefited from the unique microstructure and excellent electrocatalytic properties of different components in the nanohybrid fiber microelectrode, an effective electrochemical sensing platform based on it has been built up for the sensitive and selective detection of H 2 O 2 , the detection limit is calculated to be 50nM when the signal-to-noise ratio is 3:1, and the linear dynamic range is up to 4.3mM, with a high sensitivity of 142µAcm -2 mM -1 . These good sensing performances, coupled with its intrinsic mechanical flexibility and biocompatibility, allow for its use in in situ real-time tracking H 2 O 2 secreted from breast cancer cell lines MCF-7 and MBA-MD-231, and evaluating the sensitivity of different cancer cells to chemotherapy or radiotherapy treatments, which hold great promise for clinic application in cancer diagnose and management. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. A study of nitrogenation of a NdFe12-xMox compound by in situ neutron powder diffraction

    International Nuclear Information System (INIS)

    Loong, C.; Short, S.M.; Lin, J.; Ding, Y.

    1998-01-01

    The effects on the crystal lattice of a NdFe 12-x Mo x (x congruent 1.7) during controlled nitrogenation over the 25 endash 600 degree C temperature range were studied by neutron powder diffraction. Prior to nitrogenation the sample contained a major phase of NdFe 10.3 Mo 1.7 and a minor phase (∼12vol%) of bcc-Fe. The sample inside the furnace was connected to a closed volume of ultrapure nitrogen gas while neutron data were collected over regular time intervals during sequential heating. Substantial nitrogen absorption occurred between 500 and 600 degree C. During the nitrogenation process the NdFe 12-x Mo x N y lattice expanded while the bcc-Fe lattice contracted. An increasing decomposition of the compound into bcc-Fe at 600 degree C was observed. The average size of the NdFe 12-x Mo x N y crystalline grains decreased starting at ∼300 degree C, reaching a minimum at ∼500 degree C and then increased markedly at higher temperatures. The development of lattice strains, on the other hand, showed an opposite trend, i.e., a maximum at 500 degree C. copyright 1998 American Institute of Physics

  6. Nitrogen-Related Constraints of Carbon Uptake by Large-Scale Forest Expansion: Simulation Study for Climate Change and Management Scenarios

    Science.gov (United States)

    Kracher, Daniela

    2017-11-01

    Increase of forest areas has the potential to increase the terrestrial carbon (C) sink. However, the efficiency for C sequestration depends on the availability of nutrients such as nitrogen (N), which is affected by climatic conditions and management practices. In this study, I analyze how N limitation affects C sequestration of afforestation and how it is influenced by individual climate variables, increased harvest, and fertilizer application. To this end, JSBACH, the land component of the Earth system model of the Max Planck Institute for Meteorology is applied in idealized simulation experiments. In those simulations, large-scale afforestation increases the terrestrial C sink in the 21st century by around 100 Pg C compared to a business as usual land-use scenario. N limitation reduces C sequestration roughly by the same amount. The relevance of compensating effects of uptake and release of carbon dioxide by plant productivity and soil decomposition, respectively, gets obvious from the simulations. N limitation of both fluxes compensates particularly in the tropics. Increased mineralization under global warming triggers forest expansion, which otherwise is restricted by N availability. Due to compensating higher plant productivity and soil respiration, the global net effect of warming for C sequestration is however rather small. Fertilizer application and increased harvest enhance C sequestration as well as boreal expansion. The additional C sequestration achieved by fertilizer application is offset to a large part by additional emissions of nitrous oxide.

  7. A new approach to estimate the in situ fractional degradation rate of organic matter and nitrogen in wheat yeast concentrates

    NARCIS (Netherlands)

    De Jonge, L. H.; Van Laar, H.; Hendriks, W. H.; Dijkstra, J.

    2015-01-01

    In the classic in situ method, small particles are removed during rinsing and hence their fractional degradation rate cannot be determined. A new approach was developed to estimate the fractional degradation rate of nutrients in small particles. This approach was based on an alternative rinsing

  8. Rumen escape nitrogen from forages in sheep: comparison of in situ and in vitro techniques using in vivo data

    NARCIS (Netherlands)

    Gosselink, J.M.J.; Dulphy, J.P.; Poncet, C.; Aufrère, J.; Tamminga, S.; Cone, J.W.

    2004-01-01

    The objective of this study was to relate in vivo data of rumen escape N (REN) of forages with REN estimated from models and with determinations of rumen undegradable N. For these determinations and models measurements from in situ and in vitro techniques were used. Eleven forages were investigated

  9. OMI and Ground-Based In-Situ Tropospheric Nitrogen Dioxide Observations over Several Important European Cities during 2005–2014

    Directory of Open Access Journals (Sweden)

    Spiru Paraschiv

    2017-11-01

    Full Text Available In this work we present the evolution of tropospheric nitrogen dioxide (NO2 content over several important European cities during 2005–2014 using space observations and ground-based in-situ measurements. The NO2 content was derived using the daily observations provided by the Ozone Monitoring Instrument (OMI, while the NO2 volume mixing ratio measurements were obtained from the European Environment Agency (EEA air quality monitoring stations database. The European cities selected are: Athens (37.98° N, 23.72° E, Berlin (52.51° N, 13.41° E, Bucharest (44.43° N, 26.10° E, Madrid (40.38° N, 3.71° W, Lisbon (38.71° N, 9.13° W, Paris (48.85° N, 2.35° E, Rome (41.9° N, 12.50° E, and Rotterdam (51.91° N, 4.46° E. We show that OMI NO2 tropospheric column data can be used to assess the evolution of NO2 over important European cities. According to the statistical analysis, using the seasonal variation, we found good correlations (R > 0.50 between OMI and ground-based in-situ observations for all of the cities presented in this work. Highest correlation coefficients (R > 0.80 between ground-based monitoring stations and OMI observations were calculated for the cities of Berlin, Madrid, and Rome. Both types of observations, in-situ and remote sensing, show an NO2 negative trend for all of locations presented in this study.

  10. 9 Nitrogen Uptake in Soils

    African Journals Online (AJOL)

    User

    + depletion zone and. L. C the mean concentration in solution. D is the soil NH4. + diffusion coefficient, and b is the soil NH. 4. + buffer power. D = DLθ fL / b. (5) where D. L is the NH. 4. + diffusion coefficient in water, θ is the soil water fraction by volume, and fL is the diffusion impedance factor. Kirk & Soliva (1997) assumed ...

  11. In-situ analysis of redistribution of carbon and nitrogen during tempering of low interstitial martensitic stainless steel

    DEFF Research Database (Denmark)

    Niessen, F.; Villa, M.; Danoix, F.

    2018-01-01

    The redistribution of C and N during tempering of X4CrNiMo16-5-1 martensitic stainless steel containing 0.034 wt% C and 0.032 wt% N was studied using in-situ synchrotron X-ray diffraction (XRD) and atom probe tomography (APT). The unit cell volume of martensite decreased continuously during...... tempering. APT showed that this volume decrease is accounted entirely for by segregation of the interstitial atoms, implying that in low interstitial martensitic stainless steel stress relaxation only contributes negligibly to changes in the martensite unit cell volume....

  12. Analysis of coffee (Coffea arabica L.) performance in relation to radiation level and rate of nitrogen supply II. Uptake and distribution of nitrogen, leaf photosynthesis and first bean yields

    NARCIS (Netherlands)

    Bote, Adugna Debela; Zana, Zewdneh; Ocho, Fikre L.; Vos, Jan

    2018-01-01

    Natural supply of nitrogen is often limiting coffee production. From the viewpoints of growth and biomass production, adequate nitrogen supply is important. Growing coffee under full sunlight not only enhances potential yields but also increases demands for nitrogen fertilizer, the extent of which

  13. In situ fabrication of nickel based oxide on nitrogen-doped graphene for high electrochemical performance supercapacitors

    Science.gov (United States)

    Pan, Denghui; Zhang, Mingmei; Wang, Ying; Yan, Zaoxue; Jing, Junjie; Xie, Jimin

    2017-10-01

    In this article, we synthesize Ni(OH)2 homogeneous grown on nitrogen-doped graphene (Ni(OH)2/NG), subsequently, small and uniform nickel oxide nanoparticle (NiO/NG) is also successfully obtained through tube furnace calcination method. The high specific capacitance of the NiO/NG electrode can reach to 1314.1 F/g at a charge and discharge current density of 2 A/g, meanwhile the specific capacitance of Ni(OH)2/NG electrode is also 1350 F/g. The capacitance of NiO/NG can remain 93.7% of the maximum value after 1000 cycles, while the Ni(OH)2/NG electrode losses 16.9% of the initial capacitance after 1000 cycles. It can be attributed to nickel hydroxide instability during charge-discharge cycles.

  14. Bandgap tailoring of in-situ nitrogen-doped TiO₂ sputtered films intended for electrophotocatalytic applications under solar light

    Energy Technology Data Exchange (ETDEWEB)

    Delegan, N.; El Khakani, M. A., E-mail: elkhakani@emt.inrs.ca [Institut National de la Recherche Scientifique, Centre Énergie, Matériaux et Télécommunications, 1650, Boulevard Lionel-Boulet, Varennes, Québec J3X-1S2 (Canada); Daghrir, R.; Drogui, P. [Institut National de la Recherche Scientifique, Centre Eau, Terre et Environnement, 490 Rue de la Couronne, Québec G1K-9A9 (Canada)

    2014-10-21

    We report on a reactive RF-sputtering process permitting the in-situ nitrogen doping of TiO₂ films in order to shift their photoactivity from UV to visible range. By carefully controlling the relative nitrogen-to-argon mass flow rate ratio (within the 0%–25% range) in the sputter deposition chamber, TiO₂:N films were grown with nitrogen contents ranging from 0 to 6.2 at. %, as determined by high-resolution X-ray spectroscopy measurements. A systematic investigation of the crystalline structure of the TiO₂:N films, as a function of their N content, revealed that low N contents (0.2–0.3 at. %) induce crystallization in the rutile phase while higher N contents (≥1.4 at. %) were accompanied with the recovery of the anatase structure with an average crystallite size of ~35 nm. By using both UV-Vis absorption and spectroscopic ellipsometry measurements, we were able to quantitatively determine the bandgap (E{sub g}) variation of the TiO₂:N films as a function of their N content. Thus, we have demonstrated that the E{sub g} of the TiO₂:N films effectively narrows from 3.2 eV down to a value as low as ~2.3 eV for the optimal N doping concentration of 3.4 at. % (higher N incorporation does not translate into further red shifting of the TiO₂:N films' E{sub g}). The photoactivity of the TiO₂:N films under visible light was confirmed through electro-photocatalytic decomposition of chlortetracycline (CTC, an emerging water pollutant) under standard 1.5AM solar radiation. Thus, CTC degradation efficiencies of up to 98% were achieved with 2 hours process cycles under simulated solar light. Moreover, the electro-photocatalytic performance of the TiO₂:N films is shown to be directly correlated to their optoelectronic properties (namely their bandgap narrowing).

  15. In situ observation of the reaction of tantalum with nitrogen in a laser heated diamond anvil cell

    Energy Technology Data Exchange (ETDEWEB)

    Friedrich, Alexandra, E-mail: friedrich@kristall.uni-frankfurt.d [Institut fuer Geowissenschaften, Goethe-Universitaet Frankfurt, Altenhoeferallee 1, D-60438 Frankfurt am Main (Germany); Winkler, Bjoern; Bayarjargal, Lkhamsuren [Institut fuer Geowissenschaften, Goethe-Universitaet Frankfurt, Altenhoeferallee 1, D-60438 Frankfurt am Main (Germany); Juarez Arellano, Erick A. [Universidad del Papaloapan, Circuito Central 200, Parque Industrial, Tuxtepec 68301 (Mexico); Morgenroth, Wolfgang; Biehler, Jasmin; Schroeder, Florian [Institut fuer Geowissenschaften, Goethe-Universitaet Frankfurt, Altenhoeferallee 1, D-60438 Frankfurt am Main (Germany); Yan, Jinyuan; Clark, Simon M. [Advanced Light Source, Lawrence Berkeley National Laboratory, MS6R2100, 1 Cyclotron Road, Berkeley, CA 94720-8226 (United States)

    2010-07-16

    Tantalum nitrides were formed by reaction of the elements at pressures between 9(1) and 12.7(5) GPa and temperatures >1600-2000 K in the laser-heated diamond anvil cell. The incorporation of small amount of nitrogen in the tantalum structure was identified as the first reaction product on weak laser irradiation. Subsequent laser heating led to the formation of hexagonal {beta}-Ta{sub 2}N and orthorhombic {eta}-Ta{sub 2}N{sub 3}, which was the stable phase at pressures up to 27 GPa and high temperatures. No evidence was found for the presence of {epsilon}-TaN, {theta}-TaN, {delta}-TaN, Ta{sub 3}N{sub 5}-I or Ta{sub 3}N{sub 5}-II, which was predicted to be the stable phase at P>17 GPa and T=2800 K, at the P,T-conditions of this experiment. The bulk modulus of {eta}-Ta{sub 2}N{sub 3} was determined to be B{sub 0}=319(6) GPa from a 2nd order Birch-Murnaghan equation of state fit to the experimental data, while quantum mechanical calculations using the density functional theory gave a bulk modulus of B{sub 0}=348.0(9) GPa for a 2nd-order fit or B{sub 0}=339(1) GPa and B{sup '}=4.67(9) for a 3rd-order fit. The values show the large incompressibility of this high-pressure phase. From the DFT data the structural compression mechanism could be determined.

  16. Portable broadband cavity-enhanced spectrometer utilizing Kalman filtering: application to real-time, in situ monitoring of glyoxal and nitrogen dioxide.

    Science.gov (United States)

    Fang, Bo; Zhao, Weixiong; Xu, Xuezhe; Zhou, Jiacheng; Ma, Xiao; Wang, Shuo; Zhang, Weijun; Venables, Dean S; Chen, Weidong

    2017-10-30

    This article describes the development and field application of a portable broadband cavity enhanced spectrometer (BBCES) operating in the spectral range of 440-480 nm for sensitive, real-time, in situ measurement of ambient glyoxal (CHOCHO) and nitrogen dioxide (NO 2 ). The instrument utilized a custom cage system in which the same SMA collimators were used in the transmitter and receiver units for coupling the LED light into the cavity and collecting the light transmitted through the cavity. This configuration realised a compact and stable optical system that could be easily aligned. The dimensions and mass of the optical layer were 676 × 74 × 86 mm 3 and 4.5 kg, respectively. The cavity base length was about 42 cm. The mirror reflectivity at λ = 460 nm was determined to be 0.9998, giving an effective absorption pathlength of 2.26 km. The demonstrated measurement precisions (1σ) over 60 s were 28 and 50 pptv for CHOCHO and NO 2 and the respective accuracies were 5% and 4%. By applying a Kalman adaptive filter to the retrieved concentrations, the measurement precisions of CHOCHO and NO 2 were improved to 8 pptv and 40 pptv in 21 s.

  17. Stimulation effect of synthetic cytokinins on the uptake and incorporation of nitrogen-15-labelled ammonium nitrate and urea in wheat leaves

    International Nuclear Information System (INIS)

    Iglewski, S.M.; Szarvas, T.; Pozsar, B.I.

    1977-01-01

    The turnover of different labelled nitrogen sources in wheat leaves has been investigated using the isotopic tracer technique. The 15 N at.% was determined in free ammonium ion, in the nitrate and the nitrite levels, and also in the non-disintegrated urea. The accumulation and the incorporation of stable nitrogen was measured in the TCA insoluble protein fraction. According to the experimental data the intensity of incorporation of urea nitrogen is relatively higher than that of the different inorganic compounds. The utilization of ammonium ion was 76% compared with the urea, whereas that of the nitrate nitrogen was 60% in the wheat leaves. The incorporation rate of the two nitrogen atoms from ammonium nitrate was 32% lower than that of the urea nitrogen, in the leaf protein of Bezostaia-1 wheat variety. The turnover of urea through the transamination was very rapid, the amination with ammonium ion was slower, and the first phase of the nitrate reduction was relatively more retarded than the nitrite reduction. The endogenous cytokinin-like biological activity and some synthetic cytokinins (kinetin, benzyladenine) have a remarkably stimulating effect on the incorporation of the different 15 N-labelled nitrogen sources into the leaf protein fraction. (author)

  18. RESPONSE OF CHILE PEPPER (Capsicum annuum L. TO SALT STRESS AND ORGANIC AND INORGANIC NITROGEN SOURCES: III. ION UPTAKE AND TRANSLOCATION

    Directory of Open Access Journals (Sweden)

    Marco Antonio Huez Lopez

    2011-07-01

    Full Text Available The combined effect of salinity and two N sources on content, uptake rate and translocation of nutrients by chile pepper plants (Capsicum annuum L. cv. Sandia was investigated in a greenhouse experiment. Either an organic-N liquid fertilizer extracted from grass clippings or ammonium nitrate, an inorganic fertilizer, were combined with three different soil salinity treatments (1.5, 4.5, and 6.5 dS m-1. Fertilizer treatments were two rates of organic-N fertilizer (120 and 200 kg ha-1 and 120 kg ha-1 of inorganic fertilizer. The combination of each N rate and source with the three salinity levels were arranged in a randomized complete block design replicated four times. The use of the organic-N source produced greater cation contents in roots, shoots, and enhanced the uptake rates and translocation of cations to shoots compared to plants fertilized with inorganic-N. The root and shoot concentration, uptake rates and root-to-shoot transport of Cl increased at increasing salinity. Higher contents of Cl and cations in chile pepper shoots in relation to roots were observed. It was also observed that high N rate from the organic source enhanced the cation contents in both roots and shoots. Salinity diminished N content, N uptake rate and root to shoot transport in both roots and shoots

  19. Species-specific effects of live roots and shoot litter on soil decomposer abundances do not forecast plant litter-nitrogen uptake.

    Science.gov (United States)

    Saj, Stéphane; Mikola, Juha; Ekelund, Flemming

    2009-08-01

    Plant species produce litter of varying quality and differ in the quality and quantity of compounds they release from live roots, which both can induce different decomposer growth in the soil. To test whether differences in decomposer growth can forecast the amount of N species acquire from plant litter, as suggested by theory, we grew individuals of three grassland plants-Holcus lanatus, Plantago lanceolata and Lotus corniculatus-in soils into which (15)N-labelled litter of either Holcus, Plantago or Lotus was added. We measured the effects of live roots and litter of each species on soil microbes and their protozoan and nematode feeders, and to link decomposer growth and plant nutrient uptake, we measured the amount of N taken up by plants from the added litter. We hypothesised that those species that induce the highest growth of microbes, and especially that of microbial feeders, will also take up the highest amount of N from the litter. We found, however, that although numbers of bacterial-feeding Protozoa and nematodes were on average lower after addition of Holcus than Plantago or Lotus litter, N uptake was higher from Holcus litter. Further, although the effects on Protozoa and bacterial- and fungal-feeding nematodes did not differ between the live plants, litter-N uptake differed, with Holcus being the most efficient compared to Plantago and Lotus. Hence, although microbes and their feeders unquestionably control N mineralization in the soil, and their growth differs among plant species, these differences cannot predict differences in litter-N uptake among plant species. A likely reason is that for nutrient uptake, other species-specific plant traits, such as litter chemistry, root proliferation ability and competitiveness for soil N, override in significance the species-specific ability of plants to induce decomposer growth.

  20. Tracing in situ amino acid uptake in plants and microbes with15N13C labelled compounds

    DEFF Research Database (Denmark)

    Andresen, Louise Christoffersen; Michelsen, Anders; Jonasson, Sven Evert

    amino acids. Furthermore, tannin addition tended to reduce plant uptake of label. By combining data on 15N recovery after 1 day in shoots and roots (fine and coarse) of the dominant heathland plants: the evergreen dwarf shrub Calluna vulgaris and the graminoid Deschampsia flexuosa, in soil...... microorganisms (chloroform fumigation extraction) and in soil water, we discuss the relative importance of free amino acids and ammonium as plant nutrients and microbial substrates in natural N-limited ecosystems with a high proportion of soil N held in tannin-N complexes. ...

  1. Applications of 15N-isotopic dilution techniques to study the recovery of nitrogen fertilizer in the soil and plant uptake in wheat cropping system

    International Nuclear Information System (INIS)

    Rouanet, Juan Luis; Godoy, Alejandra; Montenegro, Adolfo; Mera, Mario; Uribe, Hamil; Pino, Ines; Parada, Ana Maria; Nario, Adriana

    1999-01-01

    Soil erosion is a major concern of the Chilean Ministry of Agriculture, which supports actions to develop new approaches in order to decrease the loss of this fragile natural resource and to promote sustainable production systems. This study, based on the management of biological, chemical and physical characteristics of the soil, was aimed to save nitrogen fertilizer. Nitrogen fertilization is the most costly production factor in wheat cropping systems on Ultisols, one of the most eroded soil types in southern Chile. A field experiment was undertaken on a Ultisol (''Buenos Aires'' Farm) at Imperial, IX Region, during 1997 and 1998, in order to assess the nitrogen and water use efficiency by a wheat crop (cv. Dalcahue-INIA) under alternative soil tillage systems. 15 N-isotopic dilution techniques allowed determining aspects of plant nutrition, nitrogen and water movement in the soil, processes not evaluated so far under these conditions. A strip-plot field layout with four replications was used , with soil tillage systems (traditional, burning/no-till, and no burning/no-till) as the main plots and crop successions (wheat-lupin-wheat and lupin-wheat-oat) as the subplots (30 m-2). In each subplot, a microplot (1m-2 ) was delimited. N fertilizer in the form of urea was added on subplots, except the microplot, at the rate of 150 kg N ha-1. 15N-labelled urea at c. 10 atom % excess, at the rate of 150 kg N ha-1, was added to the microplots. The fertilizer was split three times, 10% at planting, 45% at tillering and 45% jointing stage. No significant differences were found for wheat grain yield among tillage treatments. N fertilizer recovery by the wheat crop was 43%, and 56% on the nitrogen found in plants was derived from soil. No significant differences for these proportions were found among treatments. Although the wheat crop did not respond to tillage treatments in terms of 15N recovery, the physiological nitrogen use efficiency, or grain production per unit of

  2. effect of irrigation with sewage wastewater on nitrogen uptake, translocation and orange fruit quality under el-gabal el-asfar condition: the use of 15N-labelled fertilizer

    International Nuclear Information System (INIS)

    Hussien, M.E.H.

    2008-01-01

    The uptake and translocation of nitrogen from sewage water and mineral fertilizer by one year old Navel orange transplants was investigated at a greenhouse pot experiment during (2005 and 2006) seasons. An isotope-aided study using 15 N-labelled ammonium sulfate was applied around the stem to assess the percentage of nitrogen in plants that is derived from fertilizer. The 15 N ammonium sulfate was applied at a rate of (6 g / pot).Treatments included irrigation with canal water or sewage water in addition to half strength Hoagland nutrient solution. Pots were irrigated to maintain the soil moisture content at field capacity. Results indicated an increase in transplants biomass using sewage water than using canal water for irrigation. A substantial increase in mineral fertilizer nitrogen uptake by roots and translocation into shoots was observed using canal water than using sewage water. Fertilizer nitrogen recovery by orange transplants under both kinds of water was low. However, fertilizer nitrogen recovery was higher under canal water than under sewage water irrigation regime although the plant biomass was higher under sewage water.The percent nitrogen derived from sewage water was higher (26.1- 49.5 %) comparing with the percent nitrogen (4.9 - 12.7 %) derived from 15 N-labelled ammonium sulfate Twenty years old Navel orange trees were selected for this study. Treatments included trees grown at field sites that have been irrigated with sewage water (S.W.) for 20, 50 and 90 years. Navel orange trees, of the same age, grown at a farm in Inshas using canal water (C.W.) from (Ismailia canal a branch of the River Nile) as a source for irrigation, was included in this study as the control. Fruits were sampled at maturity and ripening stages. Results of the physical characteristics of the fruits showed an increase in fruit weight, volume, but reduction in firmness and color development (from green to yellow color) relative to the control and as the irrigation period

  3. Leaf δ15N as an indicator of arbuscular mycorrhizal nitrogen uptake in a coastal-plain forest (restinga forest) at Southeastern Brazil

    Science.gov (United States)

    Mardegan, S. F.; Valadares, R.; Martinelli, L.

    2013-12-01

    Restinga diversity contrasts with a series of adverse environmental conditions that constrain their development, including nutrient limitation. In this sense, the mutualistic symbiosis between plants and arbuscular mycorrhizal fungi (AMF) may contribute in nutrient acquisition, including nitrogen. However, this association deeply affects plant nitrogen isotopic composition (δ15N), since assimilation processes and biochemical reactions within the fungi may reflect in a delivered product with an isotopic composition about 8 to 10 ‰ lower than that observed at the fungal symbiont per se. Here we assessed if the association with AMF affects δ15N values of plant species from a coastal-plain forest (restinga forest) at Southeastern Brazil. Accordingly, we analyzed the nutritional and isotopic compositions from ecosystem key-compartments (soil, litter and leaves), relating plant δ15N with the colonization rates. The study was carried out in a permanent plot (1 ha) at a coastal-plain forest (restinga forest) at the Serra do Mar State Park, SP, Brazil. Sampled vegetation is characterized by the lack of a well-defined stratification and a rather open canopy. It also comprises trees ranging from 10 to 15-m high. Soils are deep and sandy, being characterized by high acidity, nutrient deficiency and a dense litter cover. We randomly collected five samples (250 mg) from topsoil (0-10 cm) and five to ten leaves from individuals belonging to 16 plant species of high relevance within the site (IVI index). We also collected superficial (0-10 cm depth) fine roots (5 g) and 13 samples (100 g) of fine litter next to the individuals sampled. Soil samples were air-dried, sieved, homogenized and used in the physical-chemical characterization. The remainder was ground to a fine powder to determine nitrogen concentrations and δ15N values. Leaves were dried at 50 °C, finely milled and used for the determination of nitrogen concentrations, C/N ratios and δ15N values. Root samples were

  4. The Use Of {sup 15}N in the Study of Nitrogen Uptake and Metabolism in Plants; Primenenie azota-15 pri izuchenii vzaimodejstviya azotnykh udobrenij s pochvoj i usvoeniya ikh rasteniyami

    Energy Technology Data Exchange (ETDEWEB)

    Gyrbuchev, I.; Dinchev, D. [Institut Pochvovedenija Im.N. Pushkarova, Sofija (Bulgaria)

    1968-07-01

    Some forty years ago Mattson attempted to represent soil solutions as ionic states. Later on, he further developed his theory with the aid of the latest achievements in physical chemistry. In 1955 Schoffield applied chemical thermodynamics to make the interrelations between the solid and liquid phases of the soil even more precise. Nitrogen occupies a special position among the plant nutrients. The greatest success in nitrogen uptake and metabolism studies, however, has been achieved only recently after the development of isotope techniques. The study of nitrogen metabolism using isotope techniques has been carried out for some years at the N. Poushkarov Institute of Soil Science using optical methods of isotope detection. Certain of the results obtained recently point to the great opportunities offered by the use of the optical method. Greenhouse and field experiments were carried out with wheat, oats and lucerne. Ammonium sulphate with 11.50 at.%, {sup 15}N,andurea 5.55 at % were used as sources of nitrogen. Depending on the conditions, the nitrogen introduced with fertilizers was utilized by the plants in amounts ranging from 47 to 56% in the greenhouses, and from 38 to 45% m the field. It was established that the soil was the source of nearly half the nitrogen of the plants. Fertilized plants took up more of the soil nitrogen than the unfertilized plants. The nitrogen introduced into the soil was found in all fractions of the plants after 24 h and was in the non-protein organic nitrogen, constitution proteins, chlorophyll and reserve proteins of the plants. The highest amounts of {sup 15}N were found in the following free amino acids: arginine, histidine, lysine and the amide aspargine. In the bound amino acids, alanine, threonine, serine and glycine were highest in {sup 15}N. Phosphorus application increased the amounts of nitrogen in the amino acids. It was established that nitrogen turnover was greatest in chlorophyll and the constitution proteins. In the

  5. Species-specific effects of live roots and shoot litter on soil decomposer abundances do not forecast plant litter-nitrogen uptake

    DEFF Research Database (Denmark)

    Saj, Stéphane; Mikola, Juha; Ekelund, Flemming

    2009-01-01

    and bacterial- and fungal-feeding nematodes did not differ between the live plants, litter-N uptake differed, with Holcus being the most efficient compared to Plantago and Lotus. Hence, although microbes and their feeders unquestionably control N mineralization in the soil, and their growth differs among plant......Plant species produce litter of varying quality and differ in the quality and quantity of compounds they release from live roots, which both can induce different decomposer growth in the soil. To test whether differences in decomposer growth can forecast the amount of N species acquire from plant...... litter, as suggested by theory, we grew individuals of three grassland plants-Holcus lanatus, Plantago lanceolata and Lotus corniculatus-in soils into which (15)N-labelled litter of either Holcus, Plantago or Lotus was added. We measured the effects of live roots and litter of each species on soil...

  6. Actinide immobilization in the subsurface environment by in-situ treatment with a hydrolytically unstable organophosphorus complexant: Uranyl uptake by calcium phytate

    International Nuclear Information System (INIS)

    Nash, K.L.; Jensen, M.P.; Schmidt, M.A.

    1997-01-01

    In addition to naturally occurring uranium and thorium, actinide ions exist in the subsurface environment as a result of accidental releases and intentional disposal practices associated with nuclear weapons production. These species present a significant challenge to cost-effective remediation of contaminated environments. An attractive approach to decreasing the probability of actinide migration in the subsurface is to transform the ions into a less mobile form by remote treatment. We have under development a process which relies on a polyfunctional organophosphorus complexant to sequester the mobile metal ions by complexation/cation exchange in the near term, and to subsequently decompose, transforming the actinides into insoluble phosphate mineral forms in the long term. Studies to date include identification of a suitable organophosphorus reagent, profiling of its decomposition kinetics, verification of the formation of phosphate mineral phases upon decomposition of the reagent, and extensive comparison of the actinide uptake ability of the calcium salt of the reagent as compared with hydroxyapatite. In this report, we briefly describe the process with focus on the cation exchange behavior of the calcium salt of the organophosphorus sequestrant

  7. Nitrogen balance during growth of cauliflower

    NARCIS (Netherlands)

    Everaarts, A.P.

    2000-01-01

    The potential for loss of nitrogen to the environment during growth of cauliflower was investigated. A comparison was made between cauliflower growth and nitrogen uptake without, and with, nitrogen application of the recommended amount (=225 kg ha-1 minus mineral nitrogen in the soil layer 0–60 cm,

  8. Common bean growth, N uptake and seed production in sandy loam soil as affected by application of plant residues, nitrogen and irrigation level

    International Nuclear Information System (INIS)

    Abdallah, A.A.G.

    2002-01-01

    Field experiment was conducted at the experimental farm, Inshas, atomic energy authority, egypt. Common bean seeds e.v. Nebrasks were cultivated in sandy loan soil using drip irrigation system prepared for this purpose. Two water regimes, i.e., 100% (793.0 m 3 /fed.) and 65% (513.0 m 3 /fed.) of maximum available water were used in main plots. Where in sub plots two fertilizers types were applied i.e., soybean plant residues which contains N 15 labelled as an organic matter without any addition of any fertilizer and nitrogen as chemical fertilizer without using organic matter. The obtained results indicated that, application of plant residues was superior for total seed yield comparing to nitrogen fertilization treatments. This N source with irrigation level of 793.33 m 3 /fed. had a slight increase in total seed yield comparing with (513.0 m 3 /fed.). Irrigation level of 513.0 m 3 /fed. (65% MAW) as well as application of soybean plant residues showed the highest value of water use efficiency. The highest value of N seed percentage was obtained irrigation level with (513.0 m 3 /fed.). Soybean plant residues improved and increased seeds N content, and total seeds protein content. Both N chemical and irrigation level (65% Maw) recorded highest values with N 15 % atom excess. This result has been obtained at two growth stages and seed yield. The same trend of N 15 % atom excess reflected N utilized with both growth stages and seed yield

  9. Mineralization-immobilization and plant uptake of nitrogen as influenced by the spatial distribution of cattle slurry in soils of different texture

    DEFF Research Database (Denmark)

    Sørensen, P.; Jensen, E.S.

    1995-01-01

    The effect of incorporating cattle slurry in soil, either by mixing or by simulated injection into a hollow in soil, on the ryegrass uptake of total N and (NH4+)-N-15-N was determined in three soils of different textrue. The N accumulation in Italian ryegrass (Lolium multiflorum L.) from slurry N...... and from an equivalent amount of NH4+-N in ((NH4)-N-15) SO4 (control) was measured during 6 months of growth in pots. After this period the total recovery of labelled N in the top soil plus herbage was similar in the slurry and the control treatments. This indicated that gaseous losses from slurry NH4+-N...... were insignificant. Consequently, the availability of slurry N to plants was mainly influenced by the mineralization-immobilization processes. The apparent utilization of slurry NH4+-N mixed into soil was 7%, 14% and 24% lower than the utilization of (NH4)(2)SO4-N in a sand soil, a sandy loam soil...

  10. The Effects of Nitrogen Addition on the Uptake and Allocation of Macro- and Micronutrients in Bothriochloa ischaemum on Loess Plateau in China

    Directory of Open Access Journals (Sweden)

    Zemin Ai

    2017-08-01

    Full Text Available The effects of nitrogen (N addition on the macro- and micronutrient concentrations, storage, and allocation of Bothriochloa ischaemum (L. Keng, a native forage plant on the Loess Plateau in China remain unclear. We studied the effects of N addition at 0 (CK, 2.5 (N1, 5.0 (N2, and 10.0 (N3 g N m-2 y-1. N addition significantly decreased the available copper (Cu, zinc (Zn, and total Cu concentration, but significantly increased the available iron concentration in the soil. Cu, manganese (Mn, and sodium (Na concentrations in aboveground tissues and potassium (K, magnesium, and Zn concentrations in belowground tissues significantly increased with N addition. Calcium (Ca concentrations in belowground tissues decreased significantly. The ratios of above- to belowground Ca, Cu, Zn, and Mn significantly increased with N addition. The maximum ratios appeared at N2 for Cu, Zn, and Mn. The aboveground, belowground, and total biomass storage of studied nutrients significantly changed with N addition, and most attained maximum values under N2 treatment. The storage ratios of above- to belowground Cu, Zn, Mn, and Na attained maximum values at N2. We conclude that N addition significantly, but differentially influence the macro- and micronutrient concentrations and storage in B. ischaemum. B. ischaemum allocated and accumulated increased macro- and micronutrients to its aboveground tissues and exhibited high total storage when the amount of N addition reached 5 g N m-2 y-1.

  11. Uptake of Different Forms of Nitrogen and Phosphorus by Three Aquatic Plants%3种水生植物对不同形态氮·磷吸收的研究

    Institute of Scientific and Technical Information of China (English)

    杨小霞; 黄晓典; 赵超; 彭少华; 韩磊

    2012-01-01

    [目的]探讨水蓼、浮萍和黑藻在水体氮、磷去除中的应用价值.[方法]在室内培养条件下,比较这3种水生植物对不同形态和浓度氮、磷的吸收效果.[结果]3种植物发挥最大N、P吸收效果的水体N、P浓度分别为1和5 mg/L.经10 d的培养,3种水生植物对铵态氮和硝态氮的去除率均达50%以上,其中浮萍对铵态氮的去除率高达63.6%;3种水生植物对磷的去除以正磷酸盐最佳,焦磷酸盐次之,偏磷酸盐最差.浮萍对这3种形态磷的去除效果均最好,去除率分别为94.7%、85.6%和70.9%.[结论]浮萍可以作为一种净化植物,可以有效地降低水中铵态氮和不同形态磷浓度.%[Objective]The nitrogen and phosphorus absorption in water by Polygonum hydropiper L. , Hydrilla verticillata (L. f. ) Royle and Lemna minor L. were studied. [Method]The uptake of nitrogen and phosphorus with different forms and concentrations by three aquatic plants was evalulated under laboratary conditions. [Result]The concentrations of N and P in water which made the plants achieve the hightest uptake of the two elements were 1 and 5 mg/L, respectively. The removal rates of NH4-N and N03-N by three plants were over 50% after 10 days treatment, and the highest removal rate (63.6% ) for NH4-N was found in Lemna minor L. Among the different forms of phosphorus, the removal efficiency by plants was followed as orthophosphate > pyrophosphate > metaphosphate. Lemna minor L. had the best removal rate for three forms of phosphorus, with a removal rate of 94.7% , 85.6% and 70.9% , respectively. [Conclusion]Lemna minor L. was an idea plant for efficient removal of NH4-N and different forms of phosphorus in water.

  12. Impacts of Watershed Characteristics and Crop Rotations on Winter Cover Crop Nitrate-Nitrogen Uptake Capacity within Agricultural Watersheds in the Chesapeake Bay Region.

    Science.gov (United States)

    Lee, Sangchul; Yeo, In-Young; Sadeghi, Ali M; McCarty, Gregory W; Hively, W Dean; Lang, Megan W

    2016-01-01

    The adoption rate of winter cover crops (WCCs) as an effective conservation management practice to help reduce agricultural nutrient loads in the Chesapeake Bay (CB) is increasing. However, the WCC potential for water quality improvement has not been fully realized at the watershed scale. This study was conducted to evaluate the long-term impact of WCCs on hydrology and NO3-N loads in two adjacent watersheds and to identify key management factors that affect the effectiveness of WCCs using the Soil and Water Assessment Tool (SWAT) and statistical methods. Simulation results indicated that WCCs are effective for reducing NO3-N loads and their performance varied based on planting date, species, soil characteristics, and crop rotations. Early-planted WCCs outperformed late-planted WCCs on the reduction of NO3-N loads and early-planted rye (RE) reduced NO3-N loads by ~49.3% compared to the baseline (no WCC). The WCCs were more effective in a watershed dominated by well-drained soils with increased reductions in NO3-N fluxes of ~2.5 kg N·ha-1 delivered to streams and ~10.1 kg N·ha-1 leached into groundwater compared to poorly-drained soils. Well-drained agricultural lands had higher transport of NO3-N in the soil profile and groundwater due to increased N leaching. Poorly-drained agricultural lands had lower NO3-N due to extensive drainage ditches and anaerobic soil conditions promoting denitrification. The performance of WCCs varied by crop rotations (i.e., continuous corn and corn-soybean), with increased N uptake following soybean crops due to the increased soil mineral N availability by mineralization of soybean residue compared to corn residue. The WCCs can reduce N leaching where baseline NO3-N loads are high in well-drained soils and/or when residual and mineralized N availability is high due to the cropping practices. The findings suggested that WCC implementation plans should be established in watersheds according to local edaphic and agronomic

  13. Impacts of Watershed Characteristics and Crop Rotations on Winter Cover Crop Nitrate-Nitrogen Uptake Capacity within Agricultural Watersheds in the Chesapeake Bay Region.

    Directory of Open Access Journals (Sweden)

    Sangchul Lee

    Full Text Available The adoption rate of winter cover crops (WCCs as an effective conservation management practice to help reduce agricultural nutrient loads in the Chesapeake Bay (CB is increasing. However, the WCC potential for water quality improvement has not been fully realized at the watershed scale. This study was conducted to evaluate the long-term impact of WCCs on hydrology and NO3-N loads in two adjacent watersheds and to identify key management factors that affect the effectiveness of WCCs using the Soil and Water Assessment Tool (SWAT and statistical methods. Simulation results indicated that WCCs are effective for reducing NO3-N loads and their performance varied based on planting date, species, soil characteristics, and crop rotations. Early-planted WCCs outperformed late-planted WCCs on the reduction of NO3-N loads and early-planted rye (RE reduced NO3-N loads by ~49.3% compared to the baseline (no WCC. The WCCs were more effective in a watershed dominated by well-drained soils with increased reductions in NO3-N fluxes of ~2.5 kg N·ha-1 delivered to streams and ~10.1 kg N·ha-1 leached into groundwater compared to poorly-drained soils. Well-drained agricultural lands had higher transport of NO3-N in the soil profile and groundwater due to increased N leaching. Poorly-drained agricultural lands had lower NO3-N due to extensive drainage ditches and anaerobic soil conditions promoting denitrification. The performance of WCCs varied by crop rotations (i.e., continuous corn and corn-soybean, with increased N uptake following soybean crops due to the increased soil mineral N availability by mineralization of soybean residue compared to corn residue. The WCCs can reduce N leaching where baseline NO3-N loads are high in well-drained soils and/or when residual and mineralized N availability is high due to the cropping practices. The findings suggested that WCC implementation plans should be established in watersheds according to local edaphic and agronomic

  14. Effects of elevated root zone CO2 and air temperature on photosynthetic gas exchange, nitrate uptake, and total reduced nitrogen content in aeroponically grown lettuce plants.

    Science.gov (United States)

    He, Jie; Austin, Paul T; Lee, Sing Kong

    2010-09-01

    Effects of elevated root zone (RZ) CO(2) and air temperature on photosynthesis, productivity, nitrate (NO(3)(-)), and total reduced nitrogen (N) content in aeroponically grown lettuce plants were studied. Three weeks after transplanting, four different RZ [CO(2)] concentrations [ambient (360 ppm) and elevated concentrations of 2000, 10,000, and 50,000 ppm] were imposed on plants grown at two air temperature regimes of 28 degrees C/22 degrees C (day/night) and 36 degrees C/30 degrees C. Photosynthetic CO(2) assimilation (A) and stomatal conductance (g(s)) increased with increasing photosynthetically active radiation (PAR). When grown at 28 degrees C/22 degrees C, all plants accumulated more biomass than at 36 degrees C/30 degrees C. When measured under a PAR >or=600 micromol m(-2) s(-1), elevated RZ [CO(2)] resulted in significantly higher A, lower g(s), and higher midday leaf relative water content in all plants. Under elevated RZ [CO(2)], the increase of biomass was greater in roots than in shoots, causing a lower shoot/root ratio. The percentage increase in growth under elevated RZ [CO(2)] was greater at 36 degrees C/30 degrees C although the total biomass was higher at 28 degrees C/22 degrees C. NO(3)(-) and total reduced N concentrations of shoot and root were significantly higher in all plants under elevated RZ [CO(2)] than under ambient RZ [CO(2)] of 360 ppm at both temperature regimes. At each RZ [CO(2)], NO(3)(-) and total reduced N concentration of shoots were greater at 28 degrees C/22 degrees C than at 36 degrees C/30 degrees C. At all RZ [CO(2)], roots of plants at 36 degrees C/30 degrees C had significantly higher NO(3)(-) and total reduced N concentrations than at 28 degrees C/22 degrees C. Since increased RZ [CO(2)] caused partial stomatal closure, maximal A and maximal g(s) were negatively correlated, with a unique relationship for each air temperature. However, across all RZ [CO(2)] and temperature treatments, there was a close correlation between

  15. Non-linear partial least square regression increases the estimation accuracy of grass nitrogen and phosphorus using in situ hyperspectral and environmental data

    NARCIS (Netherlands)

    Ramoelo, A.; Skidmore, A.K.; Cho, M.A.; Mathieu, R.; Heitkonig, I.M.A.; Dudeni-Tlhone, N.; Schlerf, M.; Prins, H.H.T.

    2013-01-01

    Grass nitrogen (N) and phosphorus (P) concentrations are direct indicators of rangeland quality and provide imperative information for sound management of wildlife and livestock. It is challenging to estimate grass N and P concentrations using remote sensing in the savanna ecosystems. These areas

  16. In situ electro-polymerization of nitrogen doped carbon dots and their application in an electrochemiluminescence biosensor for the detection of intracellular lead ions.

    Science.gov (United States)

    Xiong, Chengyi; Liang, Wenbin; Wang, Haijun; Zheng, Yingning; Zhuo, Ying; Chai, Yaqin; Yuan, Ruo

    2016-04-25

    Here, a novel sensitive electrochemiluminescence (ECL) biosensor using N doped carbon dots (N-CDs) in situ electro-polymerized onto a glassy carbon electrode (GCE) as luminophores, and Pd-Au hexoctahedrons (Pd@Au HOHs) as enhancers, was developed for the detection of intracellular lead ions (Pb(2+)).

  17. What happens in the bag? : development and evaluation of a modified in situ protocol to estimate degradation of nitrogen and starch in the rumen

    NARCIS (Netherlands)

    Jonge, de L.H.

    2015-01-01

    The most widely used method to estimate the rumen degradation of dietary components in feedstuffs is the in situ or in sacco method. This method is based on rumen incubation of substrate (feed) in nylon or dacron bags followed by rinsing and analysis of the residue. Small pores

  18. Non-linear partial least square regression increases the estimation accuracy of grass nitrogen and phosphorus using in situ hyperspectral and environmental data

    CSIR Research Space (South Africa)

    Ramoelo, Abel

    2013-06-01

    Full Text Available in situ hyperspectral and environmental variables yielded the highest grass N and P estimation accuracy (R2 = 0.81, root mean square error (RMSE) = 0.08, and R2 = 0.80, RMSE = 0.03, respectively) as compared to using remote sensing variables only...

  19. Nitrogen loss from karst area in China in recent 50 years: An in-situ simulated rainfall experiment's assessment.

    Science.gov (United States)

    Song, Xianwei; Gao, Yang; Green, Sophie M; Dungait, Jennifer A J; Peng, Tao; Quine, Timothy A; Xiong, Bailian; Wen, Xuefa; He, Nianpeng

    2017-12-01

    Karst topography covers more than 1/3 of the People's Republic of China in area. The porous, fissured, and soluble nature of the underlying karst bedrock (primarily dolomite and limestone) leads to the formation of underground drainage systems. Karst conduit networks dominate this system, and rainfall takes a crucial role on water cycle at China karst area. Nitrogen loss from the karst system is of particular concern, with regard to nutrient use efficiency as well as water quality, as much of the karst system, including steeply sloping terrain, is used for intensive agriculture. We use simulated rainfall experiments to determine the relationship between rainfall and nitrogen loss at typical karst slope land and then estimate nitrogen loss from the karst soil. The results show that both surface runoff and subsurface runoff have a significant linear correlation with rainfall at all studied sites. Subsurface runoff is larger than surface runoff at two karst sites, while the opposite is true at the non-karst site. Exponential function satisfactorily described the correlation between rainfall and nitrogen concentrations in runoff. Nitrates accounted for 60%-95% of the dissolved nitrogen loss (DN, an index of N-loss in this research). The estimated annual N-loss load varies between 1.05 and 1.67 Tg N/year in the whole karst regions of China from 1961 to 2014. Approximately, 90% of the N-loss load occurred during the wet season, and 90% of that passed through the subsurface. Understanding the processes and estimating N-loss is highly valuable in determining long-term soil security and sustainability in karst regions.

  20. Comparison of the flows of nitrogen and inorganic phosphorous, dissolved in the Cienaga Grande de Santa Marta, Colombian Caribbean; obtained from incubation cameras in situ and incubation of silt nucleus in laboratory

    International Nuclear Information System (INIS)

    Navas S, Gabriel R; Zea Sven; Campos, Nestor Hernando

    2002-01-01

    This research focused on the comparison of low cost methodologies to determine ionic nitrogen and phosphorous fluxes across the soft sediment-water interface in Cienaga Grande de Santa Marta. In situ transparent incubation chambers and sediment cores for laboratory incubation were employed. It was found that inside the incubation chambers a depletion of dissolved oxygen occurred thus the incubation couldn't be extended for more than six hours, time insufficiently to detect important variations in concentration of the analyzed ions. Furthermore in addition, chambers were difficult to handle. Twenty-four hour sediment core incubation in the laboratory did not have the above-mentioned problems. Oxygen concentration could be kept constant, and ion concentration changes were generally large enough to allow quantitative estimations of the fluxes

  1. In Situ High-Level Nitrogen Doping into Carbon Nanospheres and Boosting of Capacitive Charge Storage in Both Anode and Cathode for a High-Energy 4.5 V Full-Carbon Lithium-Ion Capacitor.

    Science.gov (United States)

    Sun, Fei; Liu, Xiaoyan; Wu, Hao Bin; Wang, Lijie; Gao, Jihui; Li, Hexing; Lu, Yunfeng

    2018-05-02

    To circumvent the imbalances of electrochemical kinetics and capacity between Li + storage anodes and capacitive cathodes for lithium-ion capacitors (LICs), we herein demonstrate an efficient solution by boosting the capacitive charge-storage contributions of carbon electrodes to construct a high-performance LIC. Such a strategy is achieved by the in situ and high-level doping of nitrogen atoms into carbon nanospheres (ANCS), which increases the carbon defects and active sites, inducing more rapidly capacitive charge-storage contributions for both Li + storage anodes and PF 6 - storage cathodes. High-level nitrogen-doping-induced capacitive enhancement is successfully evidenced by the construction of a symmetric supercapacitor using commercial organic electrolytes. Coupling a pre-lithiated ANCS anode with a fresh ANCS cathode enables a full-carbon LIC with a high operating voltage of 4.5 V and high energy and power densities thereof. The assembled LIC device delivers high energy densities of 206.7 and 115.4 Wh kg -1 at power densities of 0.225 and 22.5 kW kg -1 , respectively, as well as an unprecedented high-power cycling stability with only 0.0013% capacitance decay per cycle within 10 000 cycles at a high power output of 9 kW kg -1 .

  2. In situ sulfur isotopes (δ{sup 34}S and δ{sup 33}S) analyses in sulfides and elemental sulfur using high sensitivity cones combined with the addition of nitrogen by laser ablation MC-ICP-MS

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Jiali [State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 430074 (China); Hu, Zhaochu, E-mail: zchu@vip.sina.com [State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 430074 (China); The Beijing SHRIMP Center, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 102206 (China); Zhang, Wen [State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 430074 (China); Yang, Lu [State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 430074 (China); National Research Council Canada, 1200 Montreal Rd., Ottawa, Ontario K1A 0R6 (Canada); Liu, Yongsheng; Li, Ming; Zong, Keqing; Gao, Shan; Hu, Shenghong [State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 430074 (China)

    2016-03-10

    The sulfur isotope is an important geochemical tracer in diverse fields of geosciences. In this study, the effects of three different cone combinations with the addition of N{sub 2} on the performance of in situ S isotope analyses were investigated in detail. The signal intensities of S isotopes were improved by a factor of 2.3 and 3.6 using the X skimmer cone combined with the standard sample cone or the Jet sample cone, respectively, compared with the standard arrangement (H skimmer cone combined with the standard sample cone). This signal enhancement is important for the improvement of the precision and accuracy of in situ S isotope analysis at high spatial resolution. Different cone combinations have a significant effect on the mass bias and mass bias stability for S isotopes. Poor precisions of S isotope ratios were obtained using the Jet and X cones combination at their corresponding optimum makeup gas flow when using Ar plasma only. The addition of 4–8 ml min{sup −1} nitrogen to the central gas flow in laser ablation MC-ICP-MS was found to significantly enlarge the mass bias stability zone at their corresponding optimum makeup gas flow in these three different cone combinations. The polyatomic interferences of OO, SH, OOH were also significantly reduced, and the interference free plateaus of sulfur isotopes became broader and flatter in the nitrogen mode (N{sub 2} = 4 ml min{sup −1}). However, the signal intensity of S was not increased by the addition of nitrogen in this study. The laser fluence and ablation mode had significant effects on sulfur isotope fractionation during the analysis of sulfides and elemental sulfur by laser ablation MC-ICP-MS. The matrix effect among different sulfides and elemental sulfur was observed, but could be significantly reduced by line scan ablation in preference to single spot ablation under the optimized fluence. It is recommended that the d{sub 90} values of the particles in pressed powder pellets for accurate

  3. In-situ study of migration and transformation of nitrogen in groundwater based on continuous observations at a contaminated desert site

    Science.gov (United States)

    Zuo, Rui; Jin, Shuhe; Chen, Minhua; Guan, Xin; Wang, Jinsheng; Zhai, Yuanzheng; Teng, Yanguo; Guo, Xueru

    2018-04-01

    The objective of this study was to explore the controlling factors on the migration and transformation of nitrogenous wastes in groundwater using long-term observations from a contaminated site on the southwestern edge of the Tengger Desert in northwestern China. Contamination was caused by wastewater discharge rich in ammonia. Two long-term groundwater monitoring wells (Wells 1# and 2#) were constructed, and 24 water samples were collected. Five key indicators were tested: ammonia, nitrate, nitrite, dissolved oxygen, and manganese. A numerical method was used to simulate the migration process and to determine the migration stage of the main pollutant plume in groundwater. The results showed that at Well 1# the nitrogenous waste migration process had essentially been completed, while at Well 2# ammonia levels were still rising and gradually transitioning to a stable stage. The differences for Well 1# and Well 2# were primarily caused by differences in groundwater flow. The change in ammonia concentration was mainly controlled by the migration of the pollution plume under nitrification in groundwater. The nitrification rate was likely affected by changes in dissolved oxygen and potentially manganese.

  4. Nitrogen uptake dynamics of a persistent cyanobacterium ...

    African Journals Online (AJOL)

    Worldwide, persistent cyanobacterial blooms are becoming more frequent and are often associated with effects of global climate change. In June 2009, a widespread bloom of the unicellular cyanobacterium, Cyanothece sp., appeared in North Lake and False Bay of Lake St Lucia – a large (360 km2) estuarine lake system ...

  5. Light Conditions Affect the Measurement of Oceanic Bacterial Production via Leucine Uptake

    Science.gov (United States)

    Morán, Xosé Anxelu G.; Massana, Ramon; Gasol, Josep M.

    2001-01-01

    The effect of irradiance in the range of 400 to 700 nm or photosynthetically active radiation (PAR) on bacterial heterotrophic production estimated by the incorporation of 3H-leucine (referred to herein as Leu) was investigated in the northwestern Mediterranean Sea and in a coastal North Atlantic site, with Leu uptake rates ranging over 3 orders of magnitude. We performed in situ incubations under natural irradiance levels of Mediterranean samples taken from five depths around solar noon and compared them to incubations in the dark. In two of the three stations large differences were found between light and dark uptake rates for the surfacemost samples, with dark values being on average 133 and 109% higher than in situ ones. Data obtained in coastal North Atlantic waters confirmed that dark enclosure may increase Leu uptake rates more than threefold. To explain these differences, on-board experiments of Leu uptake versus irradiance were performed with Mediterranean samples from depths of 5 and 40 m. Incubations under a gradient of 12 to 1,731 μmol of photons m−2 s−1 evidenced a significant increase in incorporation rates with increasing PAR in most of the experiments, with dark-incubated samples departing from this pattern. These results were not attributed to inhibition of Leu uptake in the light but to enhanced bacterial response when transferred to dark conditions. The ratio of dark to light uptake rates increased as dissolved inorganic nitrogen concentrations decreased, suggesting that bacterial nutrient deficiency was overcome by some process occurring only in the dark bottles. PMID:11525969

  6. In-situ Monitoring of Plant-microbe Communication to Understand the Influence of Soil Properties on Symbiotic Biological Nitrogen Fixation

    Science.gov (United States)

    Webster, T.; Del Valle, I.; Cheng, H. Y.; Silberg, J. J.; Masiello, C. A.; Lehmann, J.

    2016-12-01

    Plant-microbe signaling is important for many symbiotic and pathogenic interactions. While this signaling often occurs in soils, very little research has evaluated the role that the soil mineral and organic matter matrix plays in plant-microbe communication. One hurdle to these studies is the lack of simple tools for evaluating how soil mineral phases and organic matter influence the availability of plant-produced flavonoids that initiate the symbiosis between nitrogen-fixing bacteria and legumes. Because of their range of hydrophobic and electrostatic properties, flavonoids represent an informative class of signaling molecules. In this presentation, we will describe studies examining the bioavailable concentrations of flavonoids in soils using traditional techniques, such as high-pressure liquid chromatography and fluorescent microbial biosensors. Additionally, we will describe our progress developing a Rhizobium leguminosarum reporter that can be deployed into soils to report on flavonoid levels. This new microbial reporter is designed so that Rhizobium only generates a volatile gas signal when it encounters a defined concentration of flavonoids. By monitoring the output of this biosensor using gas chromatography-mass spectrometry during real time during soil incubations, we are working to establish the impact of soil organic matter, pH, and mineral phases on the reception of these signaling molecules. We expect that the findings from these studies will be useful for recommending soil management strategies that can enhance the communication between legumes and nitrogen fixing bacteria. This research highlights the importance of studying the role of soil as a mediator of plant-microbe communication.

  7. Study of the oxide reduction and interstitial contents during sintering of different plain carbon steels by in situ mass spectrometry in nitrogen atmosphere

    International Nuclear Information System (INIS)

    Momeni, Mohammad; Gierl, Christian; Danninger, Herbert

    2011-01-01

    Highlights: → Degassing phenomenon was studied in plain steels with different iron base powders. → The integrated area below the MS m12 graph can be used as an indicator of formed CO. → The integrated area is an indicator for in situ carbon loss in the specimen. → Carbon loss and area below the m12 graph can be correlated. - Abstract: Reduction of oxides covering powder particles is an important process during sintering and a prerequisite to form sintering contacts in PM parts. In the present research, degassing and reduction phenomena during sintering of plain carbon steels prepared from different atomised and sponge iron powders were studied by mass spectrometry (MS) in the dilatometer under protective N 2 atmosphere. Interstitial constituents were measured by carbon and oxygen analysis. According to the results, the major part of CO 2 is formed during carbothermic reduction of surface oxides in the low to moderate temperature range ( 600 deg. C, the main product of carbothermic reduction is CO and not CO 2 , but the former cannot be detected by MS in N 2 atmosphere. Signals m44 (CO 2 ) and m12 (C) were however found to be reliable indicators for CO. Similar intensity of mass 12 signals for both ASC and SC up to 1000 deg. C is consistent with equal carbon loss through carbothermic reaction. The integrated areas below the MS signal graphs, and thus the areas of the different degassing peaks obtained in the MS, were used as at least semi-quantitative estimation of the amount of gases formed, bearing in mind that MS is not really a quantitative analytical tool. Although a clearly defined relationship is not visible between oxygen loss and area below the m16 graph, the area for m12 can be used as an indicator for in situ carbon loss in the specimen. Increasing integrated areas for m12 and 16 between 800 and 1300 deg. C with only marginal enhancement of m44 indicates that the major part of oxides are removed as CO, in agreement with Boudouard equilibrium, at

  8. Blue-green fluorescence and visible-infrared reflectance of corn (Zea mays L.) grain for in situ field detection of nitrogen supply

    International Nuclear Information System (INIS)

    McMurtrey, J.E. III; Chappelle, E.W.; Kim, M.S.; Corp, L.A.; Daughtry, C.S.T.

    1996-01-01

    The sensing of spectral attributes of corn (Zea mays L.) grain from site specific areas of the field during the harvest process may be useful in managing agronomic inputs and production practices on those areas of the field in subsequent growing seasons. Eight levels of nitrogen (N) fertilization were applied to field grown corn at Beltsville, Maryland. These N treatments produced a range of chlorophyll levels, biomass and physiological condition in the live plant canopies. After harvest, spectra were obtained in the laboratory on whole grain samples. Fluorescence emissions were acquired from 400 to 600 nm and percent reflectance were measured in the visible (VIS) near infrared (NIR) and mid-infrared (MIR) regions from 400 nm to 2400 nm. A ultraviolet (UV) excitation band centered at 385 nm was the most effective in producing fluorescence emission differences in the blue-green region of the fluorescence spectrum with maxima centered from 430-470nm in the blue and with an intense shoulder centered at around 530-560 nm in the green region. Reflectance showed the most spectral differences in the NIR and MIR (970-2330 nm) regions

  9. Zn2+ in-situ substitution behavior during the formation of BaTiO3 coatings from plasma-sprayed powders collected in liquid nitrogen

    Science.gov (United States)

    Liu, Zhe; Xing, Zhiguo; Wang, Haidou; Xue, Zifan; Chen, Shuying; Cui, Xiufang; Jin, Guo

    2018-04-01

    The dielectric performance of BaTiO3 ceramic coatings is enhanced significantly by the addition of ZnO. In this study, the maximum relative permittivity value (εr ≈ 923) was measured in BaTiO3 coatings with ZnO added at 6 wt%. The Curie temperature (Tc) was in the range of 111 °C-121 °C for all of the ZnO-modified BaTiO3 coatings. Tc shifted to low temperatures as the ZnO content increased. Detailed analyses were performed to determine the phase composition and optical band gaps of powders collected in liquid nitrogen, which showed that the Zn2+ ions were incorporated into the BaTiO3 lattice where they substituted into the Ti4+ sites, and the composite powders (BaTiO3 + 6 wt% ZnO) tolerated high temperatures in the plasma beam. In addition, some residual Zn accumulated in the grain boundary in the form of ZnO. X-ray diffraction and Raman spectroscopy showed that the substitution led to changes in the compositional and structural properties. The red shift in the optical band gap of BaTiO3 indicated that the ZnTi'' defects caused by the dopants acted as carriers in the doped BaTiO3 coatings.

  10. Enhanced Oxygen Reduction Reaction by In Situ Anchoring Fe2N Nanoparticles on Nitrogen-Doped Pomelo Peel-Derived Carbon

    Directory of Open Access Journals (Sweden)

    Yiqing Wang

    2017-11-01

    Full Text Available The development of effective oxygen electrode catalysts for renewable energy technologies such as metal-air batteries and fuel cells remains challenging. Here, we prepared a novel high-performance oxygen reduction reaction (ORR catalyst comprised of Fe2N nanoparticles (NPs in situ decorated over an N-doped porous carbon derived from pomelo peel (i.e., Fe2N/N-PPC. The decorated Fe2N NPs provided large quantities of Fe-N-C bonding catalytic sites. The as-obtained Fe2N/N-PPC showed superior onset and half-wave potentials (0.966 and 0.891 V, respectively in alkaline media (0.1 M KOH compared to commercial Pt/C through a direct four-electron reaction pathway. Fe2N/N-PPC also showed better stability and methanol tolerance than commercial Pt/C. The outstanding ORR performance of Fe2N/N-PPC was attributed to its high specific surface area and the synergistic effects of Fe2N NPs. The utilization of agricultural wastes as a precursor makes Fe2N/N-PPC an ideal non-precious metal catalyst for ORR applications.

  11. In situ bioremediation under high saline conditions

    International Nuclear Information System (INIS)

    Bosshard, B.; Raumin, J.; Saurohan, B.

    1995-01-01

    An in situ bioremediation treatability study is in progress at the Salton Sea Test Base (SSTB) under the NAVY CLEAN 2 contract. The site is located in the vicinity of the Salon Sea with expected groundwater saline levels of up to 50,000 ppm. The site is contaminated with diesel, gasoline and fuel oils. The treatability study is assessing the use of indigenous heterotrophic bacteria to remediate petroleum hydrocarbons. Low levels of significant macro nutrients indicate that nutrient addition of metabolic nitrogen and Orthophosphate are necessary to promote the process, requiring unique nutrient addition schemes. Groundwater major ion chemistry indicates that precipitation of calcium phosphorus compounds may be stimulated by air-sparging operations and nutrient addition, which has mandated the remedial system to include pneumatic fracturing as an option. This presentation is tailored at an introductory level to in situ bioremediation technologies, with some emphasize on innovations in sparge air delivery, dissolved oxygen uptake rates, nutrient delivery, and pneumatic fracturing that should keep the expert's interest

  12. Narrowband NIR-Induced In Situ Generation of the High-Energy Trans Conformer of Trichloroacetic Acid Isolated in Solid Nitrogen and its Spontaneous Decay by Tunneling to the Low-Energy Cis Conformer

    Directory of Open Access Journals (Sweden)

    R. F. G. Apóstolo

    2015-12-01

    Full Text Available The monomeric form of trichloroacetic acid (CCl3COOH; TCA was isolated in a cryogenic nitrogen matrix (15 K and the higher energy trans conformer (O=C–O–H dihedral: 180° was generated in situ by narrowband near-infrared selective excitation the 1st OH stretching overtone of the low-energy cis conformer (O=C–O–H dihedral: 0°. The spontaneous decay, by tunneling, of the generated high-energy conformer into the cis form was then evaluated and compared with those observed previously for the trans conformers of acetic and formic acids in identical experimental conditions. The much faster decay of the high-energy conformer of TCA compared to both formic and acetic acids (by ~35 and ca. 25 times, respectively was found to correlate well with the lower energy barrier for the trans→cis isomerization in the studied compound. The experimental studies received support from quantum chemistry calculations undertaken at the DFT(B3LYP/cc-pVDZ level of approximation, which allowed a detailed characterization of the potential energy surface of the molecule and the detailed assignment of the infrared spectra of the two conformers.

  13. In-situ carbon and nitrogen turnover dynamics and the role of soil functional biodiversity therein; a climate warming simulation study in Alpine ecosystems

    Science.gov (United States)

    Djukic, Ika

    2010-05-01

    Climate change affects a variety of soil properties and processes. Alpine soils take an extraordinary position in this context because of the vulnerability of mountain regions to climatic changes. We used altitudinal soil translocation to simulate the combined effects of changing climatic conditions and shifting vegetation zones in order to study short- to medium-term soil changes in the Austrian Limestone Alps. We translocated 160 soil cores from an alpine grassland site (1900 m asl) down to a sub-alpine spruce forest (1300 m asl) and a montane beech forest site (900m asl), including reference soil cores at each site to estimate artifacts arising from the method. 15N-labeled maize straw was added (1 kg/m2) to translocated and control soil cores and sampled over a period of 2 years for the analysis of δ13C and δ15N in the bulk soil and extracted phospholipid fatty acids (PLFAs). Additionally, 20 litter bags (at each of the three climatic zones) containing Fagus sylvatica or Pinus nigra litter were inserted into the soil, and decomposition was studied over a two-year period. The basic soil parameters (organic C, total N and pH) were unaffected by translocation within the observation time. Overall, decomposition of Pinus nigra litter was significantly slower compared to Fagus sylvatica, and the decomposition rate of both litter types was inversely related to elevation. The decomposition of the maize straw carbon was significantly faster in the translocated soil cores (sites at 900 and 1300 m asl) than at the original site (1900 m asl). The labelled nitrogen contents in the translocated soil cores showed just marginal differences to the soil cores at the original site. The maize straw application promptly increased the amount of bacterial and fungal PLFAs at all studied sites. Downslope translocated soil cores showed an increase in total microbial biomass and sum of bacteria. The fungal PLFA biomarker 18:2ω6,9 was slightly lower at the new (host) sites compared to

  14. [Characteristics of dry matter production and nitrogen accumulation in barley genotypes with high nitrogen utilization efficiency].

    Science.gov (United States)

    Huang, Yi; Li, Ting-Xuan; Zhang, Xi-Zhou; Ji, Lin

    2014-07-01

    A pot experiment was conducted under low (125 mg x kg-1) and normal (250 mg x kg(-1)) nitrogen treatments. The nitrogen uptake and utilization efficiency of 22 barley cultivars were investigated, and the characteristics of dry matter production and nitrogen accumulation in barley were analyzed. The results showed that nitrogen uptake and utilization efficiency were different for barley under two nitrogen levels. The maximal values of grain yield, nitrogen utilization efficiency for grain and nitrogen harvest index were 2.87, 2.91 and 2.47 times as those of the lowest under the low nitrogen treatment. Grain yield and nitrogen utilization efficiency for grain and nitrogen harvest index of barley genotype with high nitrogen utilization efficiency were significantly greater than low nitrogen utilization efficiency, and the parameters of high nitrogen utilization efficiency genotype were 82.1%, 61.5% and 50.5% higher than low nitrogen utilization efficiency genotype under the low nitrogen treatment. Dry matter mass and nitrogen utilization of high nitrogen utilization efficiency was significantly higher than those of low nitrogen utilization efficiency. A peak of dry matter mass of high nitrogen utilization efficiency occurred during jointing to heading stage, while that of nitrogen accumulation appeared before jointing. Under the low nitrogen treatment, dry matter mass of DH61 and DH121+ was 34.4% and 38.3%, and nitrogen accumulation was 54. 8% and 58.0% higher than DH80, respectively. Dry matter mass and nitrogen accumulation seriously affected yield before jointing stage, and the contribution rates were 47.9% and 54.7% respectively under the low nitrogen treatment. The effect of dry matter and nitrogen accumulation on nitrogen utilization efficiency for grain was the largest during heading to mature stages, followed by sowing to jointing stages, with the contribution rate being 29.5% and 48.7%, 29.0% and 15.8%, respectively. In conclusion, barley genotype with high

  15. Nutrient uptake dynamics across a gradient of nutrient concentrations and ratios at the landscape scale

    Science.gov (United States)

    Gibson, Catherine A.; O'Reilly, Catherine M.; Conine, Andrea L.; Lipshutz, Sondra M.

    2015-02-01

    Understanding interactions between nutrient cycles is essential for recognizing and remediating human impacts on water quality, yet multielemental approaches to studying nutrient cycling in streams are currently rare. Here we utilized a relatively new approach (tracer additions for spiraling curve characterization) to examine uptake dynamics for three essential nutrients across a landscape that varied in absolute and relative nutrient availability. We measured nutrient uptake for soluble reactive phosphorous, ammonium-nitrogen, and nitrate-nitrogen in 16 headwater streams in the Catskill Mountains, New York. Across the landscape, ammonium-nitrogen and soluble reactive phosphorus had shorter uptake lengths and higher uptake velocities than nitrate-nitrogen. Ammonium-nitrogen and soluble reactive phosphorus uptake velocities were tightly correlated, and the slope of the relationship did not differ from one, suggesting strong demand for both nutrients despite the high ambient water column dissolved inorganic nitrogen: soluble reactive phosphorus ratios. Ammonium-nitrogen appeared to be the preferred form of nitrogen despite much higher nitrate-nitrogen concentrations. The uptake rate of nitrate-nitrogen was positively correlated with ambient soluble reactive phosphorus concentration and soluble reactive phosphorus areal uptake rate, suggesting that higher soluble reactive phosphorus concentrations alleviate phosphorus limitation and facilitate nitrate-nitrogen uptake. In addition, these streams retained a large proportion of soluble reactive phosphorus, ammonium-nitrogen, and nitrate-nitrogen supplied by the watershed, demonstrating that these streams are important landscape filters for nutrients. Together, these results (1) indicated phosphorus limitation across the landscape but similarly high demand for ammonium-nitrogen and (2) suggested that nitrate-nitrogen uptake was influenced by variability in soluble reactive phosphorus availability and preference for

  16. Nitrogen saturation in stream ecosystems.

    Science.gov (United States)

    Earl, Stevan R; Valett, H Maurice; Webster, Jackson R

    2006-12-01

    The concept of nitrogen (N) saturation has organized the assessment of N loading in terrestrial ecosystems. Here we extend the concept to lotic ecosystems by coupling Michaelis-Menten kinetics and nutrient spiraling. We propose a series of saturation response types, which may be used to characterize the proximity of streams to N saturation. We conducted a series of short-term N releases using a tracer (15NO3-N) to measure uptake. Experiments were conducted in streams spanning a gradient of background N concentration. Uptake increased in four of six streams as NO3-N was incrementally elevated, indicating that these streams were not saturated. Uptake generally corresponded to Michaelis-Menten kinetics but deviated from the model in two streams where some other growth-critical factor may have been limiting. Proximity to saturation was correlated to background N concentration but was better predicted by the ratio of dissolved inorganic N (DIN) to soluble reactive phosphorus (SRP), suggesting phosphorus limitation in several high-N streams. Uptake velocity, a reflection of uptake efficiency, declined nonlinearly with increasing N amendment in all streams. At the same time, uptake velocity was highest in the low-N streams. Our conceptual model of N transport, uptake, and uptake efficiency suggests that, while streams may be active sites of N uptake on the landscape, N saturation contributes to nonlinear changes in stream N dynamics that correspond to decreased uptake efficiency.

  17. Brucella, nitrogen and virulence.

    Science.gov (United States)

    Ronneau, Severin; Moussa, Simon; Barbier, Thibault; Conde-Álvarez, Raquel; Zuniga-Ripa, Amaia; Moriyon, Ignacio; Letesson, Jean-Jacques

    2016-08-01

    The brucellae are α-Proteobacteria causing brucellosis, an important zoonosis. Although multiplying in endoplasmic reticulum-derived vacuoles, they cause no cell death, suggesting subtle but efficient use of host resources. Brucellae are amino-acid prototrophs able to grow with ammonium or use glutamate as the sole carbon-nitrogen source in vitro. They contain more than twice amino acid/peptide/polyamine uptake genes than the amino-acid auxotroph Legionella pneumophila, which multiplies in a similar vacuole, suggesting a different nutritional strategy. During these two last decades, many mutants of key actors in nitrogen metabolism (transporters, enzymes, regulators, etc.) have been described to be essential for full virulence of brucellae. Here, we review the genomic and experimental data on Brucella nitrogen metabolism and its connection with virulence. An analysis of various aspects of this metabolism (transport, assimilation, biosynthesis, catabolism, respiration and regulation) has highlighted differences and similarities in nitrogen metabolism with other α-Proteobacteria. Together, these data suggest that, during their intracellular life cycle, the brucellae use various nitrogen sources for biosynthesis, catabolism and respiration following a strategy that requires prototrophy and a tight regulation of nitrogen use.

  18. Terrestrial nitrogen cycles: Some unanswered questions

    Science.gov (United States)

    Vitousek, P.

    1984-01-01

    Nitrogen is generally considered to be the element which most often limits the growth of plants in both natural and agricultural ecosystems. It regulates plant growth because photosynthetic rates are strongly dependent on the concentration of nitrogen in leaves, and because relatively large mounts of protein are required for cell division and growth. Yet nitrogen is abundant in the biosphere - the well-mixed pool in the atmosphere is considered inexhaustible compared to biotic demand, and the amount of already fixed organic nitrogen in soils far exceeds annual plant uptake in terrestrial ecosystems. In regions where natural vegetation is not nitrogen limited, continuous cultivation induces nitrogen deficiency. Nitrogen loss from cultivated lands is more rapid than that of other elements, and nitrogen fertilization is generally required to maintain crop yield under any continuous system. The pervasiveness of nitrogen deficiency in many natural and most managed sites is discussed.

  19. Absorção e redistribuição do nitrogênio aplicado via foliar em videiras jovens Uptake and redistribution of nitrogen in foliar application in young grapevines

    Directory of Open Access Journals (Sweden)

    Gustavo Brunetto

    2005-04-01

    Full Text Available A aplicação de nitrogênio via foliar antes da senescência das folhas da videira pode ser uma estratégia para aumentar as reservas deste nutriente nas partes perenes, uma vez que as mesmas são disponibilizadas no início do crescimento vegetativo dos órgãos anuais. O objetivo deste trabalho foi de estimar a absorção e a redistribuição do N adicionado via foliar em videiras jovens. O experimento foi instalado em casa de vegetação na EMBRAPA-Uva e Vinho, no município de Bento Gonçalves (RS. Foram utilizadas as variedades Chardonnay e Riesling Itálico com porta-enxerto 101-14 Mgt. Foi cultivada uma planta por vaso contendo 10kg de solo Neossolo Litólico. A aplicação do N via foliar foi parcelada em três vezes, durante três dias sucessivos. Foram aplicados 84,84mg N planta-1 na forma de (15NH42SO4 . As plantas foram colhidas em sete épocas diferentes. Após a colheita, as plantas foram fracionadas em folhas, enxerto, porta-enxerto, raízes grossas (>2mm e raízes finas (The foliar application of nitrogen before the leaves senescence may be a strategy to increase the nutrient reserves in the perennial parts, being available in the beginning of the vegetative growth of the annual parts. The objective of this work was to estimate the uptake and redistribution of N applied by foliar way in young grapevines. The experiment was carried out in a greenhouse at EMBRAPA-Grape and Wine, Bento Gonçalves Southern Brazil. The cultivars used were Chardonnay and Riesling Italic grafted on rootstock 101-14 Mgt. It was cultivated one plant by vase with 10kg of soil Udorthent. The foliar application of N was parceled in three times during three successive days. It was applied 84,84mg N plant-1 using (15NH42SO4 . The plants were collected in seven times, during vegetative growth. The plants were fractionated in leaves, graft, carry-graft, thick roots (>2mm and fine roots (<2mm, oven-dried, weighted, and analyzed N-total and 15N contents. The

  20. Forests, nitrogen and albedo, a very interesting trio indeed

    Directory of Open Access Journals (Sweden)

    Borghetti M

    2009-01-01

    Full Text Available A short comment is made on a recent paper (Ollinger et al. 2008 which shows that forest ecosystem carbon uptake in temperate and boreal forests is directly related to canopy nitrogen concentration and that both carbon uptake capacity and canopy nitrogen concentration are positively correlated with shortwave surface albedo measured with broad-band satellite sensors.

  1. Uptake of crude petroleum hydrocarbons by mudflat bacteria ...

    African Journals Online (AJOL)

    SERVER

    2007-08-06

    Aug 6, 2007 ... bacteria exposed to nitrogenous fertilizer plant ... accompanied by a rapid decline in the level of crude petroleum in the amended .... conductivity, turbidity, salinity, dissolved oxygen (fresh sample only) ... Nutrient uptake was.

  2. Effect of organic manure on nitrogen mineralization, nitrogen accumulation, nitrogen use efficiency and apparent nitrogen recovery of cauliflower (Braccica oleracea L., var. Botrytis)

    NARCIS (Netherlands)

    Beah, A.A.; Norman, P.E.; Scholberg, J.M.S.; Lantinga, E.A.; Conteh, A.R.

    2015-01-01

    Aims: The main aim of the study was to assess the effects of organic manure on nitrogen mineralization, uptake, use and recovery of cauliflower.
    Methodology: Nitrogen is one of the major yield limiting nutrients in cauliflower production. However, organic manure is applied to supplement soil

  3. Genotypic variation of nitrogen use efficiency in Indian mustard

    International Nuclear Information System (INIS)

    Ahmad, Altaf; Khan, Ishrat; Abrol, Yash P.; Iqbal, Muhammad

    2008-01-01

    This experiment was conducted to investigate the variation of nitrogen efficiency (NE), nitrogen uptake efficiency (UE), physiological nitrogen use efficiency (PUE) among Indian mustard genotypes, grown under N-insufficient and N-sufficient conditions. Nitrogen efficiency varied from 52.7 to 92.8. Seed yield varied from 1.14 t ha -1 to 3.21 t ha -1 under N-insufficient condition, while 2.14 t ha -1 -3.33 t ha -1 under N-sufficient condition. Physiological basis of this difference was explained in terms of nitrogen uptake efficiency and physiological nitrogen use efficiency, and their relationship with the growth and yield characteristics. While nitrogen uptake efficiency was positively correlated with plant biomass (0.793**), leaf area index (0.664*), and leaf nitrogen content (0.783**), physiological nitrogen use efficiency is positively correlated with photosynthetic rate (0.689**) and yield (0.814**). This study suggests that genotype having high nitrogen uptake efficiency and high physiological nitrogen use efficiency might help in reducing the nitrogen load on soil without any penalty on the yield. - Nitrogen efficient crop plants may help in reducing environmental contamination of nitrate without any penalty on seed yield

  4. Investigation on the Assimilation of Nitrogen by Maize Roots and the Transport of Some Major Nitrogen Compounds by Xylem Sap

    DEFF Research Database (Denmark)

    Ivanko, S.; Ingversen, J.

    1971-01-01

    The uptake and assimilation of nitrate and ammonia have been studied in Zea mays. Nitrogen-starved maize roots are capable of accumulating a potential capacity for nitrogen uptake and assimilation. Reestablishment of nitrogen supply leads to intense uptake, reaching 154 % of the reference variant...... level after 24 hours when nitrate is supplied, and 121 % when ammonia is supplied. After 24 hours the insoluble nitrogen fraction accounts for 80, 54 and 55 % of the total taken up in the PK + NO3-, PK + NH4+ and NPK variants respectively....

  5. Increased breast density correlates with the proliferation-seeking radiotracer (99m)Tc(V)-DMSA uptake in florid epithelial hyperplasia and in mixed ductal carcinoma in situ with invasive ductal carcinoma but not in pure invasive ductal carcinoma or in mild epithelial hyperplasia.

    Science.gov (United States)

    Papantoniou, Vassilios; Valsamaki, Pipitsa; Sotiropoulou, Evangelia; Tsaroucha, Angeliki; Tsiouris, Spyridon; Sotiropoulou, Maria; Marinopoulos, Spyridon; Kounadi, Evangelia; Karianos, Theodore; Fothiadaki, Athina; Archontaki, Aikaterini; Syrgiannis, Konstantinos; Ptohis, Nikolaos; Makris, Nikolaos; Limouris, Georgios; Antsaklis, Aris

    2011-10-01

    The purpose of this study was to assess the relationship of mammographic breast density (BD) and cell proliferation/focal adhesion kinase activation-seeking radiotracer technetium 99m pentavalent dimercaptosuccinic acid (99mTc(V)-DMSA) uptake in women with different breast histologies, that is, mild epithelial hyperplasia (MEH), florid epithelial hyperplasia (FEH), mixed ductal carcinoma in situ with invasive ductal carcinoma (DCIS + IDC), and pure IDC. Fifty-five women with histologically confirmed mammary pathologies were submitted preoperatively to mammography and 99mTc(V)-DMSA scintimammography. The percentage and intensity of 99mTc(V)-DMSA uptake and the percentage of BD were calculated by computer-assisted methods and compared (t-test) between the breast pathologies. In breasts with increased BD, FEH and DCIS + IDC were found. On the contrary, pure IDC and MEH were identified in breasts with significantly lower BD values. In breasts with increased 99mTc(V)-DMSA area and intensity of uptake, FEH was the main lesion found compared to all other histologies. Linear regression analysis between BD and 99mTc(V)-DMSA uptake area and intensity revealed significant coefficients of correlation (r  =  .689, p < .001 and r  =  .582, p < .001, respectively). Increased BD correlates with the presence of FEH and mixed DCIS + IDC but not with pure IDC or MEH. Its close relationship to 99mTc(V)-DMSA, which also showed an affinity to FEH, indicates that stromal microenvironment may constitute a specific substrate leading to progression to different subtypes of cancerous lesions originating from different pathways.

  6. Response of bread wheat to increasing mustard meal nitrogen ...

    African Journals Online (AJOL)

    Greenhouse experiment on the nitrogen uptake from the mustard meal using 15N showed significant difference on both soil types. On the Vertisol the per cent nitrogen derived from the meal and per cent nitrogen use efficiency varied from 18 to 40 and from 18 to 62%, respectively. On the Nitosol, these values varied from 25 ...

  7. Isotope studies on the comparative efficiency of nitrogenous sources

    Energy Technology Data Exchange (ETDEWEB)

    Dev, G; Rennie, D A [Saskatchewan Univ., Saskatoon (Canada). Dept. of Soil Science

    1979-03-01

    In a growth chamber experiment with /sup 15/N-labelled potassium nitrate, ammonium sulphate and urea at 75 and 150kg nitrogen/ha and ammonium nitrate at 150kg nitrogen/ha, nitrogen application produced significant responses of dry matter yield and total nitrogen uptake by shoot and root of barley in chernozemic dark brown Elstow silt loam and deep black Hoey clay soil. Total nitrogen removal per pot and isotope-derived criteria, viz. percentage nitrogen derived from fertilizer, 'A' value and percentage fertilizer nitrogen utilization, indicated that potassium nitrate was the most efficient and urea the least.

  8. Nitrogen cycling in Hot Spring Sediments and Biofilms (Invited)

    Science.gov (United States)

    Meyer-Dombard, D. R.; Burton, M. S.; Havig, J. R.; Shock, E.

    2010-12-01

    capacity for nitrogen fixation as a function of changing community structure become apparent. Our results provide insight into shifts in genomic and transcriptomic function in the context of niches within hot spring environments, and the effect of availability of fixed nitrogen on the growth habit of microbial communities in situ in these ecosystems. [1] Havig et al., 2010. Merging isotopes and community genomics in a siliceous sinter-depositing hot spring. Journal of Geophysical Research-Biogeosciences (in press). [2] Raymond et al., 2008. EOS Trans AGU. Abstract B14A-03. [3] Hall et al., 2008. Molecular characterization of the diversity and distribution of a thermal spring microbial community using rRNA and metabolic genes. AEM 74:4910-4922. [4] Steunou et al., 2006. In situ analysis of nitrogen fixation and metabolic switching in unicellular thermophilic Cyanobacteria inhabiting hot spring microbial mats. PNAS 103:2398-2403. [5] Boyd et al., 2009. CO2 uptake and fixation by a thermoacidophilic microbial community attached to precipitated sulfur in a geothermal spring. AEM 75:4289-4296.

  9. Enhanced nitrogen deposition over China

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xuejun; Zhang, Ying; Han, Wenxuan; Tang, Aohan; Shen, Jianlin; Cui, Zhenling; Christie, Peter; Zhang, Fusuo [College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193 (China); Vitousek, Peter [Department of Biology, Stanford University, Stanford, California 94305 (United States); Erisman, Jan Willem [VU University Amsterdam, 1081 HV Amsterdam (Netherlands); Goulding, Keith [The Sustainable Soils and Grassland Systems Department, Rothamsted Research, Harpenden AL5 2JQ (United Kingdom); Fangmeier, Andreas [Institute of Landscape and Plant Ecology, University of Hohenheim, 70593 Stuttgart (Germany)

    2013-02-28

    China is experiencing intense air pollution caused in large part by anthropogenic emissions of reactive nitrogen. These emissions result in the deposition of atmospheric nitrogen (N) in terrestrial and aquatic ecosystems, with implications for human and ecosystem health, greenhouse gas balances and biological diversity. However, information on the magnitude and environmental impact of N deposition in China is limited. Here we use nationwide data sets on bulk N deposition, plant foliar N and crop N uptake (from long-term unfertilized soils) to evaluate N deposition dynamics and their effect on ecosystems across China between 1980 and 2010. We find that the average annual bulk deposition of N increased by approximately 8 kilograms of nitrogen per hectare (P < 0.001) between the 1980s (13.2 kilograms of nitrogen per hectare) and the 2000s (21.1 kilograms of nitrogen per hectare). Nitrogen deposition rates in the industrialized and agriculturally intensified regions of China are as high as the peak levels of deposition in northwestern Europe in the 1980s, before the introduction of mitigation measures. Nitrogen from ammonium (NH4+) is the dominant form of N in bulk deposition, but the rate of increase is largest for deposition of N from nitrate (NO3-), in agreement with decreased ratios of NH3 to NOx emissions since 1980. We also find that the impact of N deposition on Chinese ecosystems includes significantly increased plant foliar N concentrations in natural and semi-natural (that is, non-agricultural) ecosystems and increased crop N uptake from long-term-unfertilized croplands. China and other economies are facing a continuing challenge to reduce emissions of reactive nitrogen, N deposition and their negative effects on human health and the environment.

  10. Dissolved organic nitrogen recalcitrance and bioavailable nitrogen quantification for effluents from advanced nitrogen removal wastewater treatment facilities

    International Nuclear Information System (INIS)

    Fan, Lu; Brett, Michael T.; Jiang, Wenju; Li, Bo

    2017-01-01

    The objective of this study was to determine the composition of nitrogen (N) in the effluents of advanced N removal (ANR) wastewater treatment plants (WWTPs). This study also tested two different experimental protocols for determining dissolved N recalcitrance. An analysis of 15 effluent samples from five WWTPs, showed effluent concentrations and especially effluent composition varied greatly from one system to the other, with total nitrogen (TN) ranging between 1.05 and 8.10 mg L −1 . Nitrate (NO 3 − ) accounted for between 38 ± 32% of TN, and ammonium accounted for a further 29 ± 28%. All of these samples were dominated by dissolved inorganic nitrogen (DIN; NO 3 −  + NH 4 + ), and uptake experiments indicated the DIN fraction was as expected highly bioavailable. Dissolved organic N (DON) accounted for 20 ± 11% for the total dissolved N in these effluents, and uptake experiments indicated the bioavailability of this fraction varied between 27 ± 26% depending on the WWTP assessed. These results indicate near complete DIN removal should be the primary goal of ANR treatment systems. The comparison of bioavailable nitrogen (BAN) quantification protocols showed that the dissolved nitrogen uptake bioassay approach was clearly a more reliable way to determine BAN concentrations compared to the conventional cell yield protocol. Moreover, because the nitrogen uptake experiment was much more sensitive, this protocol made it easier to detect extrinsic factors (such as biological contamination or toxicity) that could affect the accuracy of these bioassays. Based on these results, we recommend the nitrogen uptake bioassay using filtered and autoclaved samples to quantify BAN concentrations. However, for effluent samples indicating toxicity, algal bioassays will not accurately quantify BAN. - Highlights: • DIN was the dominated N pool for most of the tested effluent samples. • DON bioavailability considerably varied depending on the WWTP assessed.

  11. Nitrogen on Mars: Insights from Curiosity

    Science.gov (United States)

    Stern, J. C.; Sutter, B.; Jackson, W. A.; Navarro-Gonzalez, Rafael; McKay, Chrisopher P.; Ming, W.; Archer, P. Douglas; Glavin, D. P.; Fairen, A. G.; Mahaffy, Paul R.

    2017-01-01

    Recent detection of nitrate on Mars indicates that nitrogen fixation processes occurred in early martian history. Data collected by the Sample Analysis at Mars (SAM) instrument on the Curiosity Rover can be integrated with Mars analog work in order to better understand the fixation and mobility of nitrogen on Mars, and thus its availability to putative biology. In particular, the relationship between nitrate and other soluble salts may help reveal the timing of nitrogen fixation and post-depositional behavior of nitrate on Mars. In addition, in situ measurements of nitrogen abundance and isotopic composition may be used to model atmospheric conditions on early Mars.

  12. Carbon-nitrogen-water interactions: is model parsimony fruitful?

    Science.gov (United States)

    Puertes, Cristina; González-Sanchis, María; Lidón, Antonio; Bautista, Inmaculada; Lull, Cristina; Francés, Félix

    2017-04-01

    It is well known that carbon and nitrogen cycles are highly intertwined and both should be explained through the water balance. In fact, in water-controlled ecosystems nutrient deficit is related to this water scarcity. For this reason, the present study compares the capability of three models in reproducing the interaction between the carbon and nitrogen cycles and the water cycle. The models are BIOME-BGCMuSo, LEACHM and a simple carbon-nitrogen model coupled to the hydrological model TETIS. Biome-BGCMuSo and LEACHM are two widely used models that reproduce the carbon and nitrogen cycles adequately. However, their main limitation is that these models are quite complex and can be too detailed for watershed studies. On the contrary, the TETIS nutrient sub-model is a conceptual model with a vertical tank distribution over the active soil depth, dividing it in two layers. Only the input of the added litter and the losses due to soil respiration, denitrification, leaching and plant uptake are considered as external fluxes. Other fluxes have been neglected. The three models have been implemented in an experimental plot of a semi-arid catchment (La Hunde, East of Spain), mostly covered by holm oak (Quercus ilex). Plant transpiration, soil moisture and runoff have been monitored daily during nearly two years (26/10/2012 to 30/09/2014). For the same period, soil samples were collected every two months and taken to the lab in order to obtain the concentrations of dissolved organic carbon, microbial biomass carbon, ammonium and nitrate. In addition, between field trips soil samples were placed in PVC tubes with resin traps and were left incubating (in situ buried cores). Thus, mineralization and nitrification accumulated fluxes for two months, were obtained. The ammonium and nitrate leaching accumulated for two months were measured using ion-exchange resin cores. Soil respiration was also measured every field trip. Finally, water samples deriving from runoff, were collected

  13. Zn(II) coordination polymer of an in situ generated 4-pyridyl (4Py) attached bis(amido)phosphate ligand, [PO2(NH4Py)2]- showing preferential water uptake over aliphatic alcohols.

    Science.gov (United States)

    Gupta, Arvind K; Nagarkar, Sanjog S; Boomishankar, Ramamoorthy

    2013-08-14

    Two polymorphic 2D-coordination polymers of composition [ZnL(HCO2)]∞ were synthesized from an in situ generated ligand [PO2(NH(4)Py)2](-) (L(-)). The ligand L(-) was generated by a facile metal-assisted P-N bond hydrolysis reaction from the corresponding phosphonium salt 1, [P(NH(4)Py)4]Cl, or from the neutral phosphoric triamide 2, [PO(NH(4)Py)3]. The de-solvated sample of the polymer [ZnL(HCO2)]∞ features polar micropores and shows a type I isotherm for CO2 sorption whereas a type II behaviour was observed for N2. The vapour sorption isotherm of the de-solvated sample of [ZnL(HCO2)]∞ shows preferential adsorption of water vapour over aliphatic alcohols.

  14. Influência do nitrogênio degradável no rúmen sobre a degradabilidade in situ, os parâmetros ruminais e a eficiência de síntese microbiana em novilhos alimentados com cana-de-açúcar Ruminal degradable nitrogen for steers fed sugar cane: in situ degradability, ruminal parameters and microbial synthesis efficiency

    Directory of Open Access Journals (Sweden)

    Roselene Nunes da Silveira

    2009-03-01

    Full Text Available Objetivou-se avaliar o efeito da deficiência de nitrogênio degradável no rúmen (NDR, utilizando como volumoso cana-de-açúcar suplementada com uréia, farelo de soja ou farelo de glúten de milho - 60, sobre a eficiência de síntese microbiana e a degradabilidade in situ da matéria seca (MS e da fibra em detergente neutro (FDN em novilhos mestiços. Utilizaram-se oito novilhos canulados no rúmen e duodeno, distribuídos em dois quadrados latinos 4 × 4 e alimentados com cana-de-açúcar e cana-de-açúcar suplementada com uréia, farelo de soja ou farelo de glúten de milho-60. O pH e a concentração de N-NH3 foram mensurados no fluido ruminal antes e 2, 4, 6 e 8 horas após o fornecimento da ração. Utilizou-se a fibra em detergente ácido indigestível como indicador de fluxo duodenal. A eficiência microbiana foi determinada pelas bases purinas.As fontes de proteína degradável no rúmen não influenciaram a degradabilidade da matéria seca, entretanto, o maior valor de degradabilidade efetiva da FDN foi obtido com a cana-de-açúcar com farelo de soja. O pH e a concentração de N-NH3 observados com todas as dietas foram adequados para o crescimento dos microrganismos ruminais. A deficiência de nitrogênio degradável no rúmen não influencia a síntese de proteína microbiana e a dinâmica de fase líquida.The objective of this work was to evaluate the ruminal degradable nitrogen (RDN deficit using as roughage sugar cane supplemented with urea, soybean meal, or corn gluten meal 60 on the microbial synthesis efficiency, in situ dry matter (DM and neutral detergent fiber (NDF degradability. The treatments were: sugar cane, sugar cane with urea, soybean meal or corn gluten meal 60. Eight rumen and duodenum cannulated steers were used and arranged according to two 4 × 4 Latin Squares. The pH and N-NH3 were determined in the ruminal fluid before and 2, 4, 6 and 8 hours after feeding. The duodenal flow was estimated by indigestible

  15. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... for a thyroid scan is 30 minutes or less. Thyroid Uptake You will be given radioactive iodine ( ... for each thyroid uptake is five minutes or less. top of page What will I experience during ...

  16. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... uptake measurements are obtained at different times. For example, you may have uptake measurements at four to ... medicine procedures can be time consuming. It can take several hours to days for the radiotracer to ...

  17. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... Scan and Uptake Thyroid scan and uptake uses small amounts of radioactive materials called radiotracers, a special ... is a branch of medical imaging that uses small amounts of radioactive material to diagnose and determine ...

  18. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... radioactive iodine uptake test (RAIU) is also known as a thyroid uptake. It is a measurement of ... potential to identify disease in its earliest stages as well as a patient’s immediate response to therapeutic ...

  19. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... known as a thyroid uptake. It is a measurement of thyroid function, but does not involve imaging. ... eating can affect the accuracy of the uptake measurement. Jewelry and other metallic accessories should be left ...

  20. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... Uptake? A thyroid scan is a type of nuclear medicine imaging. The radioactive iodine uptake test (RAIU) ... of thyroid function, but does not involve imaging. Nuclear medicine is a branch of medical imaging that ...

  1. Dissolved organic nitrogen recalcitrance and bioavailable nitrogen quantification for effluents from advanced nitrogen removal wastewater treatment facilities.

    Science.gov (United States)

    Fan, Lu; Brett, Michael T; Jiang, Wenju; Li, Bo

    2017-10-01

    The objective of this study was to determine the composition of nitrogen (N) in the effluents of advanced N removal (ANR) wastewater treatment plants (WWTPs). This study also tested two different experimental protocols for determining dissolved N recalcitrance. An analysis of 15 effluent samples from five WWTPs, showed effluent concentrations and especially effluent composition varied greatly from one system to the other, with total nitrogen (TN) ranging between 1.05 and 8.10 mg L -1 . Nitrate (NO 3 - ) accounted for between 38 ± 32% of TN, and ammonium accounted for a further 29 ± 28%. All of these samples were dominated by dissolved inorganic nitrogen (DIN; NO 3 -  + NH 4 + ), and uptake experiments indicated the DIN fraction was as expected highly bioavailable. Dissolved organic N (DON) accounted for 20 ± 11% for the total dissolved N in these effluents, and uptake experiments indicated the bioavailability of this fraction varied between 27 ± 26% depending on the WWTP assessed. These results indicate near complete DIN removal should be the primary goal of ANR treatment systems. The comparison of bioavailable nitrogen (BAN) quantification protocols showed that the dissolved nitrogen uptake bioassay approach was clearly a more reliable way to determine BAN concentrations compared to the conventional cell yield protocol. Moreover, because the nitrogen uptake experiment was much more sensitive, this protocol made it easier to detect extrinsic factors (such as biological contamination or toxicity) that could affect the accuracy of these bioassays. Based on these results, we recommend the nitrogen uptake bioassay using filtered and autoclaved samples to quantify BAN concentrations. However, for effluent samples indicating toxicity, algal bioassays will not accurately quantify BAN. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Uptake rate of nitrogen from soil and fertilizer, and N derived from symbiotic fixation in cowpea (Vigna unguiculata (L.) Walp.) and common bean (Phaseolus vulgaris L.) determined using the 15N isotope

    International Nuclear Information System (INIS)

    Brito, Marciano de Medeiros Pereira; Muraoka, Takashi; Silva, Edson Cabral da

    2009-01-01

    Common bean (Phaseolus vulgaris L.) and cowpea (Vigna unguiculata (L.) Walp.) are among the main sources of plant protein for a large part of the world population, mainly that of low income, and nitrogen is the main constituent of these proteins. The objectives of this study were to evaluate, through the 15 N-dilution technique and using rice and non-nodulating soybean as control plants, the relative contributions of nitrogen sources (symbiotically fixed N, soil native N and fertilizer N) on the growth of common bean and cowpea and to compare the isotopic technique (ID) with the difference methods (DM) for the evaluation of symbiotic N 2 fixation. The study was carried out in a greenhouse of the Center for Nuclear Energy in Agriculture - CENA/USP, Sao Paulo State, Brazil, using 5 kg pots with a Typic Haplustox (Dystrophic Red-Yellow Latosol). The experiment was arranged in completely randomized blocks, with 16 treatments and three replications, in an 8 x 2 factorial design. The treatments were eight sampling times: 7, 24, 31, 38, 47, 58, 68 and 78 days after sowing (DAS) and two crops: common bean and cowpea. An N rate of 10 mg kg -1 soil was used, as urea, enriched with an excess of 10 % of 15 N atoms. Symbiotic N fixation supplied the bean and cowpea plants with the greatest amount of accumulated N, followed, in decreasing order, by soil and fertilizer. The highest rate of N symbiotic fixation was observed at the pre-flowering growth stage of the bean and cowpea plants. After the initial growth stage, 24 DAS, rice and non nodulating soybean were appropriate control plants to evaluate symbiotic N fixation. There was a good agreement between ID and DM, except in the initial growth stage of the crops. (author)

  3. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... for a thyroid scan is 30 minutes or less. Thyroid Uptake You will be given radioactive iodine (I-123 or I-131) in liquid or capsule form to swallow. The thyroid uptake will begin several hours to 24 hours later. Often, two separate uptake ...

  4. nitrogen saturation in stream ecosystems

    OpenAIRE

    Earl, S. R.; Valett, H. M.; Webster, J. R.

    2006-01-01

    The concept of nitrogen (N) saturation has organized the assessment of N loading in terrestrial ecosystems. Here we extend the concept to lotic ecosystems by coupling Michaelis-Menten kinetics and nutrient spiraling. We propose a series of saturation response types, which may be used to characterize the proximity of streams to N saturation. We conducted a series of short-term N releases using a tracer ((NO3)-N-15-N) to measure uptake. Experiments were conducted in streams spanning a gradient ...

  5. Forest fuel reduces the nitrogen load

    International Nuclear Information System (INIS)

    Lundborg, A.

    1993-03-01

    A study of the literature was made on the basis of the following hypothesis: ''If nitrogen-rich felling residues are removed from the forest, the nitrogen load on the forest ecosystem is decreased and the risk of nitrogen saturation also decreases''. The study was designed to provide information on how the nitrogen situation is influenced if felling residues are removed from nitrogen-loaded forests and used as fuel. Felling residues release very little nitrogen during the first years after felling. They can immobilize nitrogen from the surroundings, make up a considerable addition to the nitrogen store in the soil, but also release nitrogen in later stages of degradation. The slash has an influence on the soil climate and thus on soil processes. Often there is an increase in the mineralization of litter and humus below the felling residues. At the same time, nitrification is favoured, particularly if the slash is left in heaps. Felling residues contain easily soluble nutrients that stimulate the metabolization of organic matter that otherwise is rather resistant to degradation. The slash also inhibits the clear-cut vegetation and its uptake of nitrogen. These effects result in increased leaching of nitrogen and minerals if the felling residues are left on the site. (99 refs.)

  6. Effect of different nitrogen application types on nitrogen utilization efficiency and fate of fertilizer for sugacane

    International Nuclear Information System (INIS)

    Wei Jianfeng; Wei Dongping; Liu Huanyu; Chen Chaojun; Lan Libin; Liang He

    2013-01-01

    A pot experiment in greenhouse was conducted with "1"5N-labeled urea 5 g/pot (equal to 450 kg · hm"-"2) total nitrogen by three kinds of treatments of disposable bottom application nitrogen before sowing (T1), 50% nitrogen before sowing and 50% nitrogrn during tillering stage (T2), and 30% nitrogen before sowing, 30% nitrogen during tillering stage and 40% nitrogen applied during elongation stage (T3) to investigate the use efficiency and fate of fertilizer nitrogen using the sugarcane cultivar ROC22. Results showed that almost 18% ∼ 29% of total N uptake by sugarcane was supplied by fertilizer, and 71% ∼ 82% N derived from soil and seed-stem. Nitrogen use efficiency ranged from 21.0% to 34.52%, with "1"5N-fertilizer residue of 37.61% ∼ 44.13%, and "1"5N-fertilizer loss of 21.35% ∼ 41.39% among three treatments. Under the three levels of nitrogen application, residual was "1"5N-fertilizer was mainly distributed in 0 ∼ 20 cm top soil. The uptake of nitrogen and the proportion of total N from fertilizer in sugarcane plant, the yield of stalk and sugar after the nitrogen applied, and the use efficiency and residue ratio of "1"5N-fertilizer increased significantly over time, while loss rate of "1"5N-fertilizer decreased significantly with a slight decline trend of nitrogen distribution and sucrose accumulation in stalk. The results also indicated that after the nitrogen applied the amounts "1"5N-fertilizer residue in 0 ∼ 20 cm top soil showed a rising trend, but dropped in 20 ∼ 40 cm soil profile. From the viewpoints of economic benefit and ecological benefit, the nitrogen fertilizer applied of T3 could be optimal treatment. (authors)

  7. Gaseous Nitrogen Losses from Tropical Savanna Soils of Northern Australia: Dynamics, Controls and Magnitude of N2O, NO, and N2 emissions

    Science.gov (United States)

    Werner, C.; Hickler, T.; Hutley, L. B.; Butterbach-Bahl, K.

    2014-12-01

    Tropical savanna covers a large fraction of the global land area and thus may have a substantial effect on the global soil-atmosphere exchange of nitrogen. The pronounced seasonality of hygric conditions in this ecosystem affects strongly microbial process rates in the soil. As these microbial processes control the uptake, production, and release of nitrogen compounds, it is thought that this seasonality finally leads to strong temporal dynamics and varying magnitudes of gaseous losses to the atmosphere. However, given their areal extent and in contrast to other ecosystems, still few in-situ or laboratory studies exist that assess the soil-atmosphere exchange of nitrogen. We present laboratory incubation results from intact soil cores obtained from a natural savanna site in Northern Australia, where N2O, NO, and N2 emissions under controlled environmental conditions were investigated. Furthermore, in-situ measurements of high temporal resolution at this site recorded with automated static and dynamic chamber systems are discussed (N2O, NO). This data is then used to assess the performance of a process-based biogeochemical model (LandscapeDNDC), and the potential magnitude and dynamics of components of the site-scale nitrogen cycle where no measurements exist (biological nitrogen fixation and nitrate leaching). Our incubation results show that severe nutrient limitation of the soil only allows for very low N2O emissions (0.12 kg N ha-1 yr-1) and even a periodic N2O uptake. Annual NO emissions were estimated at 0.68 kg N ha-1 yr-1, while the release of inert nitrogen (N2) was estimated at 6.75 kg N ha-1 yr-1 (data excl. contribution by pulse emissions). We observed only minor N2O pulse emissions after watering the soil cores and initial rain events of the dry to wet season transition in-situ, but short-lived NO pulse emissions were substantial. Interestingly, some cores exhibited a very different N2O emission potential, indicating a substantial spatial variability of

  8. Thyroid uptake test

    International Nuclear Information System (INIS)

    Ganatra, R.D.

    1992-01-01

    The uptake of radioiodine by the thyroid gland is altered by the iodine content of diet or drugs. American diet has a high iodine content because each slice of the white bread contains nearly 150μg of iodine due to the bleaching process employed in the production of the bread. This carrier content of iodine reduces the uptake so much, that the normal American uptakes are usually three to four times lower than the uptakes in the developing countries. The other drawback of the thyroid uptake test is that it is affected by the iodine containing drugs. Anti-diarrhoea medications are quire common in the developing countries and many of them contain iodine moiety. Without a reliable drug history, a low thyroid uptake value may lead to a misleading conclusion

  9. Nitrogen cycling in a turbid, tidal estuary

    NARCIS (Netherlands)

    Andersson, M.G.I.

    2007-01-01

    In this thesis I investigated nitrification, dissolved inorganic and organic nitrogen uptake, and the relative importance of nitrification and ammonium assimilation. I have also investigated exchange with marshes and sediments. Nitrification, oxidation of ammonium to nitrate is the first step for

  10. Environmental factors affecting rates of nitrogen cycling

    International Nuclear Information System (INIS)

    Lipschultz, F.

    1984-01-01

    The nitrogen cycle in the eutrophic Delaware river was studied in late summer, 1983 using 15 N tracer additions of NHG 4 + , NO 2 - , and NO 3 - . Rates for nine different transformations were calculated simultaneously with a least-squares minimization analysis. Light was found to stimulate ammonium uptake and to inhibit ammonium oxidation. Rates for nitrification, ammonium uptake by phytoplankton, and photosynthesis were integrated over 24 hours and river depth. High turbidity lifted the effect of light inhibition on nitrification and restricted phytoplankton uptake. Uptake of ammonium contributed over 95% of the inorganic nitrogen ration for phytoplankton, with dark uptake accounting for more than 50%. A mass-conservation, box model of river was used to calculate rate constants required to reproduce observed nutrient concentration changes. The calculated constants correlated well with the measured 15 N and oxygen integrated rates. Water-column nitrification was the major loss term for NH 4 + , while water column regeneration was the primary source. Loss of oxidized nitrogen was insignificant. Oxygen consumption and air-water exchange far exceeded net photosynthetic oxygen production. Nitrification contributed less than 1% to the oxygen demand near Philadelphia but up to 25% further downstream. Production of NO and N 2 O was measured under varying oxygen concentrations in batch cultures of the nitrifying bacteria Nitrosomonas europaea and Nitrosococcus oceanus. Production of both gases increased relative to nitrite production as oxygen levels decreased

  11. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician ... of nuclear medicine imaging. The radioactive iodine uptake test (RAIU) is also known as a thyroid uptake. ...

  12. Thyroid Scan and Uptake

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    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Thyroid Scan and Uptake Thyroid scan and uptake uses ...

  13. Effect of different doses of urea on the uptake of cadmium from soil ...

    African Journals Online (AJOL)

    Yomi

    2012-01-19

    Jan 19, 2012 ... uptake by canola (Brassica napus L.) applied in full and split doses. Nine different ... production of ruminants being reared on the pasture. Key words: ... combined nitrogen fertilizer used in today's agricultural practices ...

  14. Nitrogen nutrition of the grape-vine (Vitis vinifera spp)

    International Nuclear Information System (INIS)

    Conradie, W.J.

    1985-12-01

    A thorough knowledge concerning the nitrogen relationship in the grape-vine is essential in order to appreciate how different patterns of uptake, assimilation, storage and utilisation of nitrogen might be advantageous in particular environmental situations. The 15 N-isotope technique has been used to determine the uptake and distribution of nitrogen absorbed during early spring, early summer and autumn. Apart from the total N fraction, protein N and soluble N were determined as well. The utilisation of labelled N applied in the field, was determined for vineyards on heavier and lighter soils

  15. Modelling the ecosystem effects of nitrogen deposition: Model of Ecosystem Retention and Loss of Inorganic Nitrogen (MERLIN

    Directory of Open Access Journals (Sweden)

    B. J. Cosby

    1997-01-01

    Full Text Available A catchment-scale mass-balance model of linked carbon and nitrogen cycling in ecosystems has been developed for simulating leaching losses of inorganic nitrogen. The model (MERLIN considers linked biotic and abiotic processes affecting the cycling and storage of nitrogen. The model is aggregated in space and time and contains compartments intended to be observable and/or interpretable at the plot or catchment scale. The structure of the model includes the inorganic soil, a plant compartment and two soil organic compartments. Fluxes in and out of the ecosystem and between compartments are regulated by atmospheric deposition, hydrological discharge, plant uptake, litter production, wood production, microbial immobilization, mineralization, nitrification, and denitrification. Nitrogen fluxes are controlled by carbon productivity, the C:N ratios of organic compartments and inorganic nitrogen in soil solution. Inputs required are: 1 temporal sequences of carbon fluxes and pools- 2 time series of hydrological discharge through the soils, 3 historical and current external sources of inorganic nitrogen; 4 current amounts of nitrogen in the plant and soil organic compartments; 5 constants specifying the nitrogen uptake and immobilization characteristics of the plant and soil organic compartments; and 6 soil characteristics such as depth, porosity, bulk density, and anion/cation exchange constants. Outputs include: 1 concentrations and fluxes of NO3 and NH4 in soil solution and runoff; 2 total nitrogen contents of the organic and inorganic compartments; 3 C:N ratios of the aggregated plant and soil organic compartments; and 4 rates of nitrogen uptake and immobilization and nitrogen mineralization. The behaviour of the model is assessed for a combination of land-use change and nitrogen deposition scenarios in a series of speculative simulations. The results of the simulations are in broad agreement with observed and hypothesized behaviour of nitrogen

  16. Nitrogen tank

    CERN Multimedia

    2006-01-01

    Wanted The technical file about the pressure vessel RP-270 It concerns the Nitrogen tank, 60m3, 22 bars, built in 1979, and installed at Point-2 for the former L3 experiment. If you are in possession of this file, or have any files about an equivalent tank (probably between registered No. RP-260 and -272), please contact Marc Tavlet, the ALICE Glimos.

  17. The effects of soil water conditions on nitrogen fertilization use efficiency

    International Nuclear Information System (INIS)

    Zhou Lingyun

    1996-01-01

    Concerning with applied nitrogen fertilizer, the uptake as well as loss of nitrogen is mainly related to soil water content. The effects of soil water condition in wheat field on the uptake, leach and loss of nitrogen fertilizer were studied using 15 N tracing technique. The results showed that within certain range of soil water supply, from 180 to 360 mm of available water storage, the loss of nitrogen was in direct proportion to the amount of fertilizer application and the nitrogen use efficiency decreased with the increase of nitrogen application. In other words, the nitrogen use efficiency descended with the nitrogen application increased in an order of 75 kgN/ha, 150 kgN/ha, 225 kgN/ha. One interesting result was that the nitrogen use efficiencies ranged from 17.0% to 30.5% for the treatments receiving the same application rate of 75 kgN/ha

  18. Identification and quantification of nitrogen nutrient deficiency in the activated sludge process using respirometry

    NARCIS (Netherlands)

    Ning, Z.; Patry, G.G.; Spanjers, H.

    2000-01-01

    Experimental protocols to identify and quantify nitrogen nutrient deficiency in the activated sludge process were developed and tested using respirometry. Respirometric experiments showed that when a nitrogen nutrient deficient sludge is exposed to ammonia nitrogen, the oxygen uptake rate (OUR) of

  19. Effects of potassium application on the accumulated nitrogen source and yield of peanut

    International Nuclear Information System (INIS)

    Wang Yuefu; Kang Yujie; Wang Minglun; Zhao Changxing

    2013-01-01

    Pot experiments and were carried out respectively to study the effects of different potassium application on soil nitrogen uptake, fertilizer nitrogen uptake, nodule nitrogen fixation and their proportion and yield of peanut (Arachis Hypogaea L.) by "1"5N tracer technique, and explore the reasons, which may provide a theoretical basis and technical guidance for peanut production in the scientific fertilizer application. Results showed that nitrogen in peanut all mainly accumulated in the kernel for different treatments of potassium fertilizer application. However, with increasing of potassium application, the increasing extent of nitrogen content of stems was the biggest during all the peanut organs, with nut shells the smallest. Properly increasing the amount of potassium can improve nitrogen content, "1"5N abundance, nitrogen and "1"5N accumulation of every organ, and promote absorption and utilization three nitrogen-source especially with the most effect for the kernel biomass (economic output). The ratio of fertilizer nitrogen, soil nitrogen and atmospheric nitrogen absorbed by peanut was respectively between 12.37%-13.10%, 38.29%-45.10%, and 42.53%-48.31% respectively. Properly increasing potassium fertilizer application improved the absorption ratio of fertilizer nitrogen and nodule nitrogen fixation, reduced the proportion of soil uptake and enhanced fertilizer nitrogen use efficiency. However, the influences of excessive application of potassium fertilizer decreased. (authors)

  20. Response of maize to reduced urea application combined with compound nitrogen fertilizer synergists

    International Nuclear Information System (INIS)

    Tian Xiuying; WANG Zhengyin

    2006-01-01

    Pot and field experiments were conducted to study the response to application rate of urea labeled with 15 N combined with compound nitrogen fertilizer synergists in the growth, yield, uptake and utilization rate of urea of maize. In pot experiment, the standard urea application rate is 120 mg/perpot; in field experiment, the standard urea application rate is 157.5 kg/hm 2 . Maize with 15 N-urea. The results showed that the growth of maize seedling was obviously promoted with appropriate dosage of compound nitrogen fertilizer synergists (20%-60% of N). The treatments of urea application rate reduced by 5%-15% and added compound nitrogen fertilizer synergists, the growth and nitrogen content of maize were not significant changed, and the total 15 N uptake and nitrogen uptake by maize were the same as CK 2 or increased a little. Nitrogen use efficiency of other treatments increased by 5.6%-7.3% comparing with CK, except the treatment of urea application rate reduced by 30%. The apparent utilization rate of nitrogen was enhanced by 7.7%-17.0%. Under the field condition, maize yield, total uptake, net uptake, physiological rate and agronomic use efficiency of nitrogen were the same as CK or increased. The apparent utilization rate of nitrogen was enhanced by 14.8%-15.2% treated with urea reduced by 5%-15% (7.8-23.7 kg/hm 2 ) and added with compound nitrogen fertilizer synergists. It was not helpful for the growth and nitrogen utilization rate of maize when urea reduced by 30% and combined with compound nitrogen fertilizer synergists. As a result, treated with urea decreased by 15% and combined with appropriate dosage of compound nitrogen fertilizer synergists (20% of urea), the growth and yield of maize had litter effect and higher the uptake and utilization of nitrogen. (authors)

  1. MACRO NUTRIENTS UPTAKE OF FORAGE GRASSES AT DIFFERENT SALINITY STRESSES

    Directory of Open Access Journals (Sweden)

    F. Kusmiyati

    2014-10-01

    Full Text Available The high concentration of sodium chloride (NaCl in saline soils has negative effects on the growth ofmost plants. The experiment was designed to evaluate macro nutrient uptake (Nitrogen, Phosphorus andPotassium of forage grasses at different NaCl concentrations in growth media. The experiment wasconducted in a greenhouse at Forage Crops Laboratory of Animal Agriculture Faculty, Diponegoro University.Split plot design was used to arrange the experiment. The main plot was forage grasses (Elephant grass(Pennisetum purpureum and King grass (Pennisetum hybrida. The sub plot was NaCl concentrationin growth media (0, 150, and 300 mM. The nitrogen (N, phosphorus (P and potassium (K uptake in shootand root of plant were measured. The result indicated increasing NaCl concentration in growth mediasignificantly decreased the N, P and K uptake in root and shoot of the elephant grass and king grass. Thepercentage reduction percentage of N, P and K uptake at 150 mM and 300 mM were high in elephant grassand king grass. It can be concluded that based on nitrogen, phosphorus and potassium uptake, elephantgrass and king grass are not tolerant to strong and very strong saline soil.

  2. Uptake of allochthonous dissolved organic matter from soil and salmon in coastal temperate rainforest streams

    Science.gov (United States)

    Jason B. Fellman; Eran Hood; Richard T. Edwards; Jeremy B. Jones

    2009-01-01

    Dissolved organic matter (DOM) is an important component of aquatic food webs. We compare the uptake kinetics for NH4-N and different fractions of DOM during soil and salmon leachate additions by evaluating the uptake of organic forms of carbon (DOC) and nitrogen (DON), and proteinaceous DOM, as measured by parallel factor (PARAFAC) modeling of...

  3. Factors affecting ammonium uptake in streams - an inter-biome perspective

    Science.gov (United States)

    Jackson R Webster; Partick J. Mulholland; Jennifer L. Tanks; H. Maurice Valett; Walter K. Dodds; Bruce J. Peterson; William B. Bowden; Clifford N. Dahm; Stuart Findlay; Stanley V. Gregory; Nancy B. Grimm; Stephen K. Hamilton; Sherri L. Johnson; Eugenia Marti; William H. McDowell; Judy L. Meyer; Donna D. Morrall; Steven A. Thomas; Wilfred M. Wollhem

    2003-01-01

    1. The Lotic Intersite Nitrogen experiment (LINX) was a coordinated study of the relationships between North American biomes and factors governing ammonium uptake in streams. Our objective was to relate inter-biome variability of ammonium uptake to physical, chemical and biological processes. 2. Data were collected from 11 streams ranging from arctic to tropical and...

  4. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... information about your thyroid’s size, shape, position and function that is often unattainable using other imaging procedures. ... thyroid uptake. It is a measurement of thyroid function, but does not involve imaging. Nuclear medicine is ...

  5. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... which are encased in metal and plastic and most often shaped like a box, attached to a ... will I experience during and after the procedure? Most thyroid scan and thyroid uptake procedures are painless. ...

  6. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... eat for several hours before your exam because eating can affect the accuracy of the uptake measurement. ... often unattainable using other imaging procedures. For many diseases, nuclear medicine scans yield the most useful information ...

  7. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... A thyroid scan is a type of nuclear medicine imaging. The radioactive iodine uptake test (RAIU) is ... thyroid function, but does not involve imaging. Nuclear medicine is a branch of medical imaging that uses ...

  8. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... Because nuclear medicine procedures are able to pinpoint molecular activity within the body, they offer the potential ... or imaging device that produces pictures and provides molecular information. The thyroid scan and thyroid uptake provide ...

  9. Thyroid Scan and Uptake

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    Full Text Available ... Actual scanning time for each thyroid uptake is five minutes or less. top of page What will ... diagnostic procedures have been used for more than five decades, and there are no known long-term ...

  10. Thyroid Scan and Uptake

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    Full Text Available ... top of page Additional Information and Resources RTAnswers.org Radiation Therapy for Head and Neck Cancer top ... Scan and Uptake Sponsored by Please note RadiologyInfo.org is not a medical facility. Please contact your ...

  11. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... When radiotracer is taken by mouth, in either liquid or capsule form, it is typically swallowed up ... radioactive iodine (I-123 or I-131) in liquid or capsule form to swallow. The thyroid uptake ...

  12. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... RAIU) is also known as a thyroid uptake. It is a measurement of thyroid function, but does ... they offer the potential to identify disease in its earliest stages as well as a patient’s immediate ...

  13. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... for several hours before your exam because eating can affect the accuracy of the uptake measurement. Jewelry ... small hand-held device resembling a microphone that can detect and measure the amount of the radiotracer ...

  14. Thyroid Scan and Uptake

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    Full Text Available ... of page What will I experience during and after the procedure? Most thyroid scan and thyroid uptake ... you otherwise, you may resume your normal activities after your nuclear medicine scan. If any special instructions ...

  15. Thyroid Scan and Uptake

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    Full Text Available ... scan and thyroid uptake provide information about the structure and function of the thyroid. The thyroid is ... computer, create pictures offering details on both the structure and function of organs and tissues in your ...

  16. Thyroid Scan and Uptake

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    Full Text Available ... eat for several hours before your exam because eating can affect the accuracy of the uptake measurement. ... its radioactivity over time. It may also pass out of your body through your urine or stool ...

  17. Thyroid Scan and Uptake

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    Full Text Available ... procedures within the last two months that used iodine-based contrast material. Your doctor will instruct you ... a type of nuclear medicine imaging. The radioactive iodine uptake test (RAIU) is also known as a ...

  18. Intraclade heterogeneity in nitrogen utilization by marine prokaryotes revealed using stable isotope probing coupled with tag sequencing (Tag-SIP

    Directory of Open Access Journals (Sweden)

    Michael Morando

    2016-12-01

    Full Text Available Nitrogen can greatly influence the structure and productivity of microbial communities through its relative availability and form. However, roles of specific organisms in the uptake of different nitrogen species remain poorly characterized. Most studies seeking to identify agents of assimilation have been correlative, indirectly linking activity measurements (e.g., nitrate uptake with the presence or absence of biological markers, particularly functional genes and their transcripts. Evidence is accumulating of previously underappreciated functional diversity in major microbial subpopulations, which may confer physiological advantages under certain environmental conditions leading to ecotype divergence. This microdiversity further complicates our view of genetic variation in environmental samples requiring the development of more targeted approaches. Here, next-generation tag sequencing was successfully coupled with stable isotope probing (Tag-SIP to assess the ability of individual phylotypes to assimilate a particular N source. Our results provide the first direct evidence of nitrate utilization by organisms thought to lack the genes required for this process including the heterotrophic clades SAR11 and the Archaeal Marine Group II (MG-II. We also provide new direct evidence of in situ nitrate utilization by the cyanobacterium Prochlorococcus in support of recent findings. Furthermore, these results revealed widespread functional heterogeneity, i.e. different levels of N assimilation within clades, likely reflecting niche partitioning by ecotypes. The addition of nitrate utilization to ecosystem and ecosystem models by these globally dominant clades will likely improve the mechanistic accuracy of these models.

  19. Nitrogen fixation, denitrification, and ecosystem nitrogen pools in relation to vegetation development in the Subarctic

    DEFF Research Database (Denmark)

    Sørensen, Pernille Lærkedal; Jonasson, Sven Evert; Michelsen, Anders

    2006-01-01

    Nitrogen (N) fixation, denitrification, and ecosystem pools of nitrogen were measured in three subarctic ecosystem types differing in soil frost-heaving activity and vegetation cover. N2-fixation was measured by the acetylene reduction assay and converted to absolute N ecosystem input by estimates...... of conversion factors between acetylene reduction and 15N incorporation. One aim was to relate nitrogen fluxes and nitrogen pools to the mosaic of ecosystem types of different stability common in areas of soil frost movements. A second aim was to identify abiotic controls on N2-fixation by simultaneous...... measurements of temperature, light, and soil moisture. Nitrogen fixation rate was high with seasonal input estimated at 1.1 g N m2 on frostheaved sorted circles, which was higher than the total plant N content and exceeded estimated annual plant N uptake several-fold but was lower than the microbial N content...

  20. Bacterial uptake of photosynthetic carbon from freshwater phytoplankton

    International Nuclear Information System (INIS)

    Coveney, M.F.

    1982-01-01

    Microheterotrophic uptake of algal extracellular products was studied in two eutrophic lakes in southern Sweden. Size fractionation was used in H 14 CO 3 uptake experiments to measure 14 C fixation in total particulate, small particulate and dissolved organic fractions. Carbon fixed in algal photosynthesis was recovered as dissolved and small particulate 14 C, representing excretion and bacterial uptake of algal products. Estimated gross extracellular release was low in these eutrophic systems, 1 to 7% of total 14 C uptake per m 2 lake surface. From 28 to 80 % of 14 C released was recovered in the small particulate fraction after ca. 4h incubation.This percentage was uniform within each depth profile, but varied directly with in situ water temperature. Laboratory time-series incubations indicated steady state for the pool of algal extracellular products on one occasion, while increasing pool size was indicated in the remaining two experiments. Uptake of photosynthetic carbon to small particles in situ was 32 to 95% of estimted heterotrophic bacterial production (as dark 14 CO 2 uptake) on four occasions. While excretion apparently was not an important loss of cabon for phytoplankton, it may have represented an important carbon source for planktonic bacteria. (author)

  1. Characterization of the Uptake of Nitrogen Oxides on Alumina Adsorbents

    National Research Council Canada - National Science Library

    Pocengal, David

    1999-01-01

    ...) to quantify nitrate and nitrite (NOx) in aqueous solutions that contained NOx exposed alumina and to correlate the quantities of these surface NOx species with the quantity of gaseous NOx sorbed...

  2. Nitrogen uptake by phytoplankton and zooxanthellae in a coral atoll

    Digital Repository Service at National Institute of Oceanography (India)

    Wafar, M.V.M.; Devassy, V.P.; Slawyk, G.; Goes, J.I.; Jayakumar, D.A.; Rajendran, A.

    by corals, and the rates varied from 223 to 775 ng-at (mg coral tissue) @u-1@@h@u-1@@ in 4 species. Urea excretion forms about 5% of total N excreted. N balance (NH@d4@@, urea, NO@d3@@) calculated from 4 species of corals shows that zooxanthellae can derive...

  3. Mixotrophy and Nitrogen Uptake by Pfiesteria Piscicida (Dinophyceae)

    Science.gov (United States)

    Alan J. Lewitus; Bonnie M. Willis; Kenneth C. Hayes; JoAnn M. Burkholder; Howard B. Gasgow; Patricia M. Gilbert

    1999-01-01

    The nutritional versatility of dinoflagellates is a complicating factor in identifying potential links between nutrient eurichment and the proliferation of harmful algal bloom. For exmaple, although dinoflagellates associated with hamful algal blooms (e.g. red tides) are generally considered to be phototrophic and we inorganic nutrients such as nitrate or phosphate,...

  4. Nitrogen utilization efficiency and nitrogen nutrition of rice crops at MADA using the microplot nitrogen balance method

    International Nuclear Information System (INIS)

    Ahmad Nazrul Abd Wahid; Abdul Razak Ruslan; Latiffah Norddin; Hazlina Abdullah; Khairuddin Abdul Rahim

    2004-01-01

    Nitrogen (N) is a very important nutrient for rice crops and is a main component of protein. Nitrogen is essential in the production of plant chlorophyll and involves in vegetative and fruit growth and development processes. Nitrogen is a critical input and exert high cost in rice crop production. Nitrogen fertilizer is not fully utilised by the rice crop; some is lost due the processes of vaporization, hydrolysis, erosion, leaching and used by other plants and microorganisms. Several agronomic practices have been studied and adopted in this country with the purpose of increasing the efficiency nitrogen fertilizer utilization and thus, reducing the output cost for rice crops. The microplot nitrogen balance method is one of the methods used to determine uptake efficiency of nitrogen fertilizers by rice crops. In this research, the microplot of 1 m x 1 m squares in paddy plot were used, to ensure that sequential sampling was done at predetermined areas. Scheduled monthly sampling of soil and rice crops was conducted until the mature stage, harvest and post-harvest period. This MINT-MADA cooperative project contains the elements of information sharing on fertilizer efficiency measurement methods by using the N-15 isotopic tracer technique and the N-balance technique in soil, besides the cooperation on use of infrastructure and facilities, expertise and labour. (Author)

  5. The cyanobacterium Mastigocladus fulfills the nitrogen demand of a terrestrial hot spring microbial mat.

    Science.gov (United States)

    Estrella Alcamán, María; Fernandez, Camila; Delgado, Antonio; Bergman, Birgitta; Díez, Beatriz

    2015-10-01

    Cyanobacteria from Subsection V (Stigonematales) are important components of microbial mats in non-acidic terrestrial hot springs. Despite their diazotrophic nature (N2 fixers), their impact on the nitrogen cycle in such extreme ecosystems remains unknown. Here, we surveyed the identity and activity of diazotrophic cyanobacteria in the neutral hot spring of Porcelana (Northern Patagonia, Chile) during 2009 and 2011-2013. We used 16S rRNA and the nifH gene to analyze the distribution and diversity of diazotrophic cyanobacteria. Our results demonstrate the dominance of the heterocystous genus Mastigocladus (Stigonematales) along the entire temperature gradient of the hot spring (69-38 °C). In situ nitrogenase activity (acetylene reduction), nitrogen fixation rates (cellular uptake of (15)N2) and nifH transcription levels in the microbial mats showed that nitrogen fixation and nifH mRNA expression were light-dependent. Nitrogen fixation activities were detected at temperatures ranging from 58 °C to 46 °C, with maximum daily rates of 600 nmol C2H4 cm(-2) per day and 94.1 nmol N cm(-2) per day. These activity patterns strongly suggest a heterocystous cyanobacterial origin and reveal a correlation between nitrogenase activity and nifH gene expression during diurnal cycles in thermal microbial mats. N and C fixation in the mats contributed ~3 g N m(-2) per year and 27 g C m(-2) per year, suggesting that these vital demands are fully met by the diazotrophic and photoautotrophic capacities of the cyanobacteria in the Porcelana hot spring.

  6. Tightening the nitrogen cycle

    OpenAIRE

    Christensen, B.T.

    2004-01-01

    The availability of nitrogen to crop plants is a universally important aspect of soil quality, and often nitrogen represents the immediate limitation to crop productivity in modern agriculture. Nitrogen is decisive for the nutritive value of plant products and plays a key role in the environmental impact of agricultural production. The fundamental doctrine of nitrogen management is to optimise the nitrogen use efficiency of both introduced and native soil nitrogen by increasing the temporal a...

  7. Uptake of radionuclides by vegetation at a High Arctic location

    International Nuclear Information System (INIS)

    Dowdall, M.; Gwynn, J.P.; Moran, C.; O'Dea, J.; Davids, C.; Lind, B.

    2005-01-01

    Radionuclide levels in vegetation from a High Arctic location were studied and compared to in situ soil concentrations. Levels of the anthropogenic radionuclide 137 Cs and the natural radionuclides 40 K, 238 U, 226 Ra and 232 Th are discussed and transfer factor (TF) values and aggregated transfer (Tag) values are calculated for vascular plants. Levels of 137 Cs in vegetation generally followed the order mosses > lichen > vascular plants. The uptake of 137 Cs in vascular plants showed an inverse relationship with the uptake of 40 K, with 137 Cs TF and Tag values generally higher than 40 K TF and Tag values. 40 K activity concentrations in all vegetation showed little correlation to associated soil concentrations, while the uptake of 238 U, 226 Ra and 232 Th by vascular and non-vascular plants was generally low. - Uptake of the anthropogenic radionuclide 137 Cs is highest for moss species

  8. Fate of nitrogenous fertilizers in forest soil

    International Nuclear Information System (INIS)

    Pang, P.C.K.

    1984-01-01

    The fate of the nitrogenous fertilizers through the processes of denitrification, ammonia volatilization, immobilization and uptake by a conifer is determined, with the aid of 15 N-labelled fertizers. The foliage of Douglas-fir was able to absorb gaseous ammonia under optimal conditions. Denitrification and immobilization of fertilizer-N by forest soil were highest with forest floor samples and decreased with depth. Laboratory studies with four-year-old Douglas-fir demostrated that a higher quantity of fertilizer-N was utilized by trees when the nitrogen was supplied as NO 3 - rather than NH 4 + . (M.A.C.) [pt

  9. Modelling nitrogen transformation and removal in mara river basin wetlands upstream of lake Victoria

    Science.gov (United States)

    Mayo, Aloyce W.; Muraza, Marwa; Norbert, Joel

    2018-06-01

    Lake Victoria, the largest lake in Africa, is a resource of social-economic potential in East Africa. This lake receives water from numerous tributaries including Mara River, which contributes about 4.8% of the total Lake water inflow. Unfortunately, Mara River basin faces environmental problems because of intensive settlement, agriculture, overgrazing in the basin and mining activities, which has lead to water pollution in the river, soil erosion and degradation, decreased soil fertility, loss of vegetation cover, decreased water infiltration capacity and increased sedimentation. One of the pollutants carried by the river includes nitrogen, which has contributed to ecological degradation of the Lake Victoria. Therefore this research work was intended to determine the effectiveness of Mara River wetland for removal of nitrogen and to establish nitrogen removal mechanisms in the wetland. To predict nitrogen removal in the wetland, the dynamics of nitrogen transformation was studied using a conceptual numerical model that takes into account of various processes in the system using STELLA II version 9.0®2006 software. Samples of model input from water, plants and sediments were taken for 45 days and were analyzed for pH, temperature, and DO in situ and chemical parameters such as NH3-N, Org-N, NO2-N, and NO3-N were analyzed in the laboratory in accordance with Standard methods. For plants, the density, dominance, biomass productivity and TN were determined and for sediments TN was analyzed. Inflow into the wetland was determined using stage-discharge relationship and was found to be 734,400 m3/day and the average wetland volume was 1,113,500 m3. Data collected by this study were used for model calibration of nitrogen transformation in this wetland while data from another wetland were used for model validation. It was found that about 37.8% of total nitrogen was removed by the wetland system largely through sedimentation (26.6%), plant uptake (6.6%) and

  10. Nitrogen fixation in Red Sea seagrass meadows

    KAUST Repository

    Abdallah, Malak

    2017-05-01

    Seagrasses are key coastal ecosystems, providing many ecosystem services. Seagrasses increase biodiversity as they provide habitat for a large set of organisms. In addition, their structure provides hiding places to avoid predation. Seagrasses can grow in shallow marine coastal areas, but several factors regulate their growth and distribution. Seagrasses can uptake different kinds of organic and inorganic nutrients through their leaves and roots. Nitrogen and phosphorous are the most important nutrients for seagrass growth. Biological nitrogen fixation is the conversion of atmospheric nitrogen into ammonia by diazotrophic bacteria. This process provides a significant source of nitrogen for seagrass growth. The nitrogen fixation is controlled by the nif genes which are found in diazotrophs. The main goal of the project is to measure nitrogen fixation rates on seagrass sediments, in order to compare among various seagrass species from the Red Sea. Moreover, we will compare the fixing rates of the Vegetated areas with the bare sediments. This project will help to ascertain the role of nitrogen fixing bacteria in the development of seagrass meadows.

  11. Thyroid uptake software

    International Nuclear Information System (INIS)

    Alonso, Dolores; Arista, Eduardo

    2003-01-01

    The DETEC-PC software was developed as a complement to a measurement system (hardware) able to perform Iodine Thyroid Uptake studies. The software was designed according to the principles of Object oriented programming using C++ language. The software automatically fixes spectrometric measurement parameters and besides patient measurement also performs statistical analysis of a batch of samples. It possesses a PARADOX database with all information of measured patients and a help system with the system options and medical concepts related to the thyroid uptake study

  12. Quantification of the impact of macrophytes on oxygen dynamics and nitrogen retention in a vegetated lowland river

    Science.gov (United States)

    Desmet, N. J. S.; Van Belleghem, S.; Seuntjens, P.; Bouma, T. J.; Buis, K.; Meire, P.

    When macrophytes are growing in the river, the vegetation induces substantial changes to the water quality. Some effects are the result of direct interactions, such as photosynthetic activity or nutrient uptake, whereas others may be attributed to indirect effects of the water plants on hydrodynamics and river processes. This research focused on the direct effect of macrophytes on oxygen dynamics and nutrient cycling. Discharge, macrophyte biomass density, basic water quality, dissolved oxygen and nutrient concentrations were in situ monitored throughout the year in a lowland river (Nete catchment, Belgium). In addition, various processes were investigated in more detail in multiple ex situ experiments. The field and aquaria measurement results clearly demonstrated that aquatic plants can exert considerable impact on dissolved oxygen dynamics in a lowland river. When the river was dominated by macrophytes, dissolved oxygen concentrations varied from 5 to 10 mg l -1. Considering nutrient retention, it was shown that the investigated in-stream macrophytes could take up dissolved inorganic nitrogen (DIN) from the water column at rates of 33-50 mg N kgdry matter-1 h. And DIN fluxes towards the vegetation were found to vary from 0.03 to 0.19 g N ha -1 h -1 in spring and summer. Compared to the measured changes in DIN load over the river stretch, it means that about 3-13% of the DIN retention could be attributed to direct nitrogen uptake from the water by macrophytes. Yet, the role of macrophytes in rivers should not be underrated as aquatic vegetation also exerts considerable indirect effects that may have a greater impact than the direct fixation of nutrients into the plant biomass.

  13. Nitrogen kinetics in aquatic plants in arctic Alaska

    International Nuclear Information System (INIS)

    McRoy, C.P.; Alexander, V.

    1975-01-01

    The kinetics of nitrogen in terms of ammonia uptake was measured for Carex aquatilis in arctic tundra ponds using 15 N tracer techniques. Nitrogen content of the leaves and primary productivity were measured throughout a growing season. The maximum uptake velocity for ammonia was 2.75 x 10 -2 % N/g dry weight per h with a Ksub(t) of 8.4-12.5 μgatoms/l. A second estimate of nitrogen uptake was made from the increase in nitrogen content throughout the season and from this a rate of 1.85 x 10 -2 % N/g dry weight per day was obtained for Carex aquatilis and 3.6 x 10 -2 % N/g dry weight per day for Arctophylla fulva. The total nitrogen concentration in the leaves was closely related to productivity, possible providing a new approach to productivity measurements for emergent vascular plants. Emergent vascular plants absorb ammonia across and translocate it to all portions of the plant. The ecological significance of this is considerable, since in many waters inorganic nitrogen content of sediment is much higher than that of the water surrounding the leaves and stems, and can provide a source of nitrogen

  14. Effect of coated urea and non-coated urea on grain yield, N uptake and N distribution in different parts of maize

    International Nuclear Information System (INIS)

    Ren Yi; Li Guihua; Zhao Linping; Zhang Shuxiang

    2011-01-01

    In order to regulate nitrogen metabolism with nitrogen application rate and to increase nitrogen use efficiency, an isotopic method was used to compare grain yield, biomass and nitrogen use efficiency of coated urea (CU) to those of non-coated urea (U) at the N application rates of 0, 100, 150 and 225 kg/hm 2 . Results showed that CU significantly increased maize N uptake from 15 N fertilizer and aboveground biomass. The nitrogen use efficiency ( 15 NUE) of CU was 13.3-21.4% greater than that of U. There was a significant different of fertilizer 15 N uptake between CU and U in maize parts. And N uptake of CU treatment followed the order of seed > leaves > straws > cob > husk, while N uptake of U treatment was in the order of seed > straws > leaves > cob > husk. The N uptake of maize parts by both CU and U followed the same order when non-isotopic method was applied. No significant variations were observed among treatments in N uptake, Nitrogen Harvest Index and grain yield. The reason maybe that low soil temperatures (< 10 ℃) from the fourth week of October to next April reduced N uptake of winter wheat, therefore, residual NO3-N in cultivated soil layer was high after harvest. Thus, maize N uptake was more dependent on the shoot growth potential than fertilizer amount and types under high amount of available nitrogen. (authors)

  15. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Thyroid Scan and Uptake ...

  16. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... information. The thyroid scan and thyroid uptake provide information about the structure and function of the thyroid. The thyroid is a gland in the neck that controls metabolism , a chemical process that regulates the rate at which the body ...

  17. Radioactive uptake by plants

    Energy Technology Data Exchange (ETDEWEB)

    Horak, O

    1986-01-01

    The fundamentals of radionuclide uptake by plants, both by leaves and roots are presented. Iodine, cesium, strontium and ruthenium are considered and a table of the measured concentrations in several agricultural plants shortly after the Chernobyl accident is presented. Another table gives the Cs and Sr transfer factors soil plants for some plants. By using them estimates of future burden can be obtained.

  18. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... type your comment or suggestion into the following text box: Comment: E-mail: Area code: Phone no: ... of a typical probe counter used for thyroid uptake exams. The patient sits with the camera directed at the neck for five minutes, and then the leg for ...

  19. Thyroid Scan and Uptake

    Science.gov (United States)

    ... type your comment or suggestion into the following text box: Comment: E-mail: Area code: Phone no: ... of a typical probe counter used for thyroid uptake exams. The patient sits with the camera directed at the neck for five minutes, and then the leg for ...

  20. Nitrogen fixation by cyanobacteria stimulates production in Baltic food webs.

    Science.gov (United States)

    Karlson, Agnes M L; Duberg, Jon; Motwani, Nisha H; Hogfors, Hedvig; Klawonn, Isabell; Ploug, Helle; Barthel Svedén, Jennie; Garbaras, Andrius; Sundelin, Brita; Hajdu, Susanna; Larsson, Ulf; Elmgren, Ragnar; Gorokhova, Elena

    2015-06-01

    Filamentous, nitrogen-fixing cyanobacteria form extensive summer blooms in the Baltic Sea. Their ability to fix dissolved N2 allows cyanobacteria to circumvent the general summer nitrogen limitation, while also generating a supply of novel bioavailable nitrogen for the food web. However, the fate of the nitrogen fixed by cyanobacteria remains unresolved, as does its importance for secondary production in the Baltic Sea. Here, we synthesize recent experimental and field studies providing strong empirical evidence that cyanobacterial nitrogen is efficiently assimilated and transferred in Baltic food webs via two major pathways: directly by grazing on fresh or decaying cyanobacteria and indirectly through the uptake by other phytoplankton and microbes of bioavailable nitrogen exuded from cyanobacterial cells. This information is an essential step toward guiding nutrient management to minimize noxious blooms without overly reducing secondary production, and ultimately most probably fish production in the Baltic Sea.

  1. Model analysis of the influence of gas diffusivity in soil on CO and H2 uptake

    International Nuclear Information System (INIS)

    Yonemura, S.; Yokozawa, M.; Kawashima, S.; Tsuruta, H.

    2000-01-01

    CO and H 2 uptake by soil was studied as a diffusion process. A diffusion model was used to determine how the surface fluxes (net deposition velocities) were controlled by in-situ microbial uptake rates and soil gas diffusivity calculated from the 3-phase system (solid, liquid, gas) in the soil. Analytical solutions of the diffusion model assuming vertical uniformity of soil properties showed that physical properties such as air-filled porosity and soil gas diffusivity were more important in the uptake process than in the emission process. To incorporate the distribution of in-situ microbial uptake, we used a 2-layer model incorporating 'a microbiologically inactive layer and an active layer' as suggested from experimental results. By numerical simulation using the 2-layer model, we estimated the effect of several factors on deposition velocities. The variations in soil gas diffusivity due to physical properties, i.e., soil moisture and air-filled porosity, as well as to the depth of the inactive layer and in-situ microbial uptake, were found to be important in controlling deposition velocities. This result shows that the diffusion process in soil is critically important for CO and H 2 uptake by soil, at least in soils with higher in-situ uptake rates and/or with large variation in soil moisture. Similar uptake rates and the difference in deposition velocity between CO and H 2 may be attributable to differences in CO and H 2 molecular diffusivity. The inactive layer is resistant to diffusion and creates uptake limits in CO and H 2 by soil. The coupling of high temperature and a thick inactive layer, common in arid soils, markedly lowers net CO deposition velocity. The temperature for maximum uptake of CO changes with depth of the inactive layer

  2. Studies on nitrogen metabolism of soybean plants, (4)

    International Nuclear Information System (INIS)

    Kato, Yasumasa; Kitada, Subaru

    1979-01-01

    Nitrogen that came from cotyledons and nitrogen ( 15 N) pulse-fed at 5 different times during the growth of young soybean plants were studied for 33-days after germination. Cotyledons furnished nitrogen to primary leaves, stems, and roots for the first 8 days, but thereafter principally to 1 st and 2 nd trifoliate leaves. Redistribution of the cotyledon-derived nitrogen from primary leaves commenced from the 14 th day after germination when their total nitrogen was still increasing. At the end of the experiment, the cotyledon-derived nitrogen was distributed approximately uniformly among 6 expanded leaves, and very small amount was found in 3 immature leaves. It was shown that soybean leaves took up 15 N (via roots) throughout the entire period of their life, and from their near-mature stage onwards, uptake and redistribution of nitrogen were observed simultaneously. Thus, the nitrogen in mature leaves was partially being renewed constantly. Considering this fact, the nitrogen supplying capacity of soybean leaves was estimated to be about two times as large as that estimated conventionally from the net loss of nitrogen during their senescence. The turnover of leaf nitrogen was closely related to the turnover of leaf protein. Influx of nitrogen was invariably accompanied by the simultaneous synthesis of leaf protein, and conversely, efflux by the simultaneous breakdown of leaf protein. Sink removal (topping treatment) prevented the breakdown of leaf protein (as measured from the rate of release of label after the pulse feeding) as well as the export of nitrogen from the leaves. The nitrogen supplying function of soybean leaves was discussed in relation to the nitrogen and protein turnover of leaves. (Kaihara, S.)

  3. 小麦/玉米/大豆和小麦/玉米/甘薯套作对根际土壤细菌群落多样性及植株氮素吸收的影响%Effect of Wheat/Maize/Soybean and Wheat/Maize/Sweet Potato Relay Strip Intercropping on Bacterial Community Diversity of Rhizosphere Soil and Nitrogen Uptake of Crops

    Institute of Scientific and Technical Information of China (English)

    雍太文; 杨文钰; 向达兵; 朱贞颖

    2012-01-01

    为探讨小麦/玉米/大豆和小麦/玉米/甘薯套作体系中根际细菌群落多样性与作物氮素高效吸收的差异特性及二者间的关系,应用变性梯度凝胶电泳(DGGE)技术研究了小麦-大豆(A1)、小麦-甘薯(A2)、玉米(A3)、小麦/玉米/大豆(A4)和小麦/玉米/甘薯(A5)5种种植模式的根际细菌群落多样性.结果表明,与A1、A2、A3及A5相比,A4套作提高了各作物在开花期(或吐丝期)与成熟期的籽粒吸氮量、地上部总吸氮量和Shannon-Weiner index多样性指数(H′).处理间的吸氮量与H′的变化规律为套作>单作、大豆茬口>甘薯茬口,以A4处理最高.不同种植模式下DGGE图谱条带的数量及亮度有较大区别,且有几条特征性条带发生了明显变化.不同种植模式间的细菌群落结构相似性较低,群落相似度系数(Cs)表现为套作与套作间>套作与单作间;A4与A5间的Cs相对较小,二者间的细菌群落结构差异较大.A4模式有利于提高根际细菌群落多样性,增强植株对氮素的吸收能力.%The aim of this study was to understand the relationship between diversity of rhizosphere bacterial community and nitrogen uptake of crops in two relay strip intercropping systems: wheat/maize/soybean and wheat/maize/sweet potato. We analyzed the diversities of rhizosphere bacterial community in five cropping systems using denaturing gradient gel electrophoresis (DGGE) based on 16S rDNA. The cropping systems included wheat-soybean (Al), wheat-sweet potato (A2), maize single cropping (A3), wheat/maize/soybean (A4), and wheat/maize/sweet potato (A5). Compared to the sole cropping systems (Al, A2, and A3 treatments), the A4 treatment showed increases in grain nitrogen uptake and total nitrogen uptake amounts of aboveground of crops at both flowering (or silking) and maturity stages, and the Shannon-Weiner indices for rhizosphere bacterial community diversity was also increased significantly. The values of nitrogen

  4. Coupling nutrient uptake and energy flow in headwater streams

    Energy Technology Data Exchange (ETDEWEB)

    Mulholland, Patrick J [ORNL; Fellows, Christine [Griffith University, Nathan, Queensland, Australia; Valett, H. Maurice [Virginia Polytechnic Institute and State University (Virginia Tech); Dahm, Cliff [University of New Mexico, Albuquerque; Thomas, Steve [University of Nebraska

    2006-08-01

    Nutrient cycling and energy flow in ecosystems are tightly linked through the metabolic processes of organisms. Greater uptake of inorganic nutrients is expected to be associated with higher rates of metabolism [gross primary production (GPP) and respiration (R)], due to assimilatory demand of both autotrophs and heterotrophs. However, relationships between uptake and metabolism should vary with the relative contribution of autochthonous and allochthonous sources of organic matter. To investigate the relationship between metabolism and nutrient uptake, we used whole-stream and benthic chamber methods to measure rates of nitrate-nitrogen (NO{sub 3}-N) uptake and metabolism in four headwater streams chosen to span a range of light availability and therefore differing rates of GPP and contributions of autochthonous carbon. We coupled whole-stream metabolism with measures of NO{sub 3}-N uptake conducted repeatedly over the same stream reach during both day and night, as well as incubating benthic sediments under both light and dark conditions. NO{sub 3}-N uptake was generally greater in daylight compared to dark conditions, and although day-night differences in whole-stream uptake were not significant, light-dark differences in benthic chambers were significant at three of the four sites. Estimates of N demand indicated that assimilation by photoautotrophs could account for the majority of NO{sub 3}-N uptake at the two sites with relatively open canopies. Contrary to expectations, photoautotrophs contributed substantially to NO{sub 3}-N uptake even at the two closed-canopy sites, which had low values of GPP/R and relied heavily on allochthonous carbon to fuel R.

  5. Invasive Andropogon gayanus (gamba grass) is an ecosystem transformer of nitrogen relations in Australian savanna.

    Science.gov (United States)

    Rossiter-Rachor, N A; Setterfield, S A; Douglas, M M; Hutley, L B; Cook, G D; Schmidt, S

    2009-09-01

    Invasion by the African grass Andropogon gayanus is drastically altering the understory structure of oligotrophic savannas in tropical Australia. We compared nitrogen (N) relations and phenology of A. gayanus and native grasses to examine the impact of invasion on N cycling and to determine possible reasons for invasiveness of A. gayanus. Andropogon gayanus produced up to 10 and four times more shoot phytomass and root biomass, with up to seven and 2.5 times greater shoot and root N pools than native grass understory. These pronounced differences in phytomass and N pools between A. gayanus and native grasses were associated with an altered N cycle. Most growth occurs in the wet season when, compared with native grasses, dominance of A. gayanus was associated with significantly lower total soil N pools, lower nitrification rates, up to three times lower soil nitrate availability, and up to three times higher soil ammonium availability. Uptake kinetics for different N sources were studied with excised roots of three grass species ex situ. Excised roots of A. gayanus had an over six times higher-uptake rate of ammonium than roots of native grasses, while native grass Eriachne triseta had a three times higher uptake rate of nitrate than A. gayanus. We hypothesize that A. gayanus stimulates ammonification but inhibits nitrification, as was shown to occur in its native range in Africa, and that this modification of the soil N cycle is linked to the species' preference for ammonium as an N source. This mechanism could result in altered soil N relations and could enhance the competitive superiority and persistence of A. gayanus in Australian savannas.

  6. Nitrogen from mountain to fjord - Annual report 1993; Nitrogen fra fjell til fjord. Aarsrapport 1993

    Energy Technology Data Exchange (ETDEWEB)

    Kaste, Oe; Bechmann, M; Toerset, K

    1994-07-01

    ``Nitrogen from mountain to fjord`` is an interdisciplinary research programme which studies the nitrogen cycle from deposition to discharge into the sea. The project includes investigation of the nitrogen budgets for two catchments and selected areas of mountain, heath, forest, crop land and fresh water. The main purpose of the project is to increase the knowledge of uptake and runoff of nitrogen and thus to improve the prediction of future effects on soil, forest, fresh water and fjords. The activities are concentrated about two water courses in Norway: Bjerkreimsvassdraget and Aulivassdraget. In Bjerkreimsvassdraget the nitrate concentration changed only little from 1992 to 1993. Relatively large variations in the nitrate concentrations were found in the forest and heath areas of the system. In Aulivassdraget the nitrogen concentration has changed considerably in 1992 and 1993. The maximum concentration measured in the main river was 13.2 mg N/l. In autumn 1992 and spring 1993 much nitrogen remained in the soil after the poor harvest of 1992 and at that time much nitrogen was carried away by the runoff. 16 refs., 19 figs., 16 tabs.

  7. Nitrogen use efficiency evaluation of aerobic rice under field capacity water potential using {sup 15}N isotopic tracer technique

    Energy Technology Data Exchange (ETDEWEB)

    Wahid, Ahmad Nazrul Abd, E-mail: a-nazrul@nuclearmalaysia.gov.my [Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, 43600, Selangor (Malaysia); Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia); Rahim, Sahibin Abd, E-mail: haiyan@ukm.edu.my [Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, 43600, Selangor (Malaysia); Rahim, Khairuddin Abdul; Harun, Abdul Rahim [Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia)

    2015-09-25

    This study was carried out to evaluate the efficiency use of the nitrogen fertilizer on aerobic rice varieties MR219-4 and MR219-9 which were grown aerobically under field capacity water potential at the controlled environment area or shield house. Direct {sup 15}N isotope tracer method was used in this study, whereby the {sup 15}N isotope was utilized as a tracer for nitrogen nutrient uptake. {sup 15}N isotope presence in the samples is determined by using emission spectrometer analysis and percentage of total nitrogen is determined by using Kjeldahl method. {sup 15}N atom access value contained in the sample will be used in determining the effectiveness of the use of nitrogen in fertilizers through the specific calculation formulas. In this work, the data several data of nitrogen derived from fertilizer (Ndff), total nitrogen, nitrogen uptake and nitrogen use efficiency was obtained.

  8. Nitrogen use efficiency evaluation of aerobic rice under field capacity water potential using 15N isotopic tracer technique

    International Nuclear Information System (INIS)

    Wahid, Ahmad Nazrul Abd; Rahim, Sahibin Abd; Rahim, Khairuddin Abdul; Harun, Abdul Rahim

    2015-01-01

    This study was carried out to evaluate the efficiency use of the nitrogen fertilizer on aerobic rice varieties MR219-4 and MR219-9 which were grown aerobically under field capacity water potential at the controlled environment area or shield house. Direct 15 N isotope tracer method was used in this study, whereby the 15 N isotope was utilized as a tracer for nitrogen nutrient uptake. 15 N isotope presence in the samples is determined by using emission spectrometer analysis and percentage of total nitrogen is determined by using Kjeldahl method. 15 N atom access value contained in the sample will be used in determining the effectiveness of the use of nitrogen in fertilizers through the specific calculation formulas. In this work, the data several data of nitrogen derived from fertilizer (Ndff), total nitrogen, nitrogen uptake and nitrogen use efficiency was obtained

  9. Nitrogen fate and Transport in Diverse Agricultural Watersheds

    Science.gov (United States)

    Essaid, H.; McCarthy, K. A.; Baker, N. T.

    2010-12-01

    Nitrogen mass budgets have been estimated for ten agricultural watersheds located in a range of hydrologic settings in order to understand the factors controlling the fate of nitrogen applied at the surface. The watersheds, study areas of the Agricultural Chemical Sources, Transport and Fate study of the U.S. Geological Survey National Water Quality Assessment Program, are located in Indiana (IN), Iowa (IA), Maryland (MD), Nebraska (NE), Mississippi (MS) and Washington (WA). They range in size from 7 to 1254 km2, with four of the watersheds nested within larger watersheds. Surface water outflow (normalized to watershed area) ranged from 4 to 83 cm/yr. Crops planted include corn, soybean, small grains, rice, cotton, orchards and vegetables. “Surplus nitrogen” was determined for each watershed by subtracting estimates of crop uptake and volatilization from estimates of nitrogen input from atmospheric deposition, plant fixation, and fertilizer and manure applications for the period from 1987 to 2004. This surplus nitrogen is transported though the watershed via surface and subsurface flow paths, while simultaneously undergoing transformations (such as denitrification and in-stream processing) that result in less export of nitrogen from the watershed. Surface-water discharge and concentration data were used to estimate the export of nitrogen from the watersheds (groundwater outflow from the watersheds was minimal). Subtracting nitrogen export from surplus nitrogen provides an estimate of the net amount of nitrogen removal occurring during internal watershed transport. Watershed average nitrogen surplus ranged from 6 to 49 kg-N/ha. The more permeable and/or greater water flux watersheds (MD, NE, and WA) tended to have larger surplus nitrogen, possibly due to less crop uptake caused by greater leaching and runoff of nitrogen. Almost all of the surplus nitrogen in the low permeability (MS) and tile drained watersheds (IA, IN) was exported from the watershed with

  10. Convergent evidence for widespread rock nitrogen sources in Earth's surface environment.

    Science.gov (United States)

    Houlton, B Z; Morford, S L; Dahlgren, R A

    2018-04-06

    Nitrogen availability is a pivotal control on terrestrial carbon sequestration and global climate change. Historical and contemporary views assume that nitrogen enters Earth's land-surface ecosystems from the atmosphere. Here we demonstrate that bedrock is a nitrogen source that rivals atmospheric nitrogen inputs across major sectors of the global terrestrial environment. Evidence drawn from the planet's nitrogen balance, geochemical proxies, and our spatial weathering model reveal that ~19 to 31 teragrams of nitrogen are mobilized from near-surface rocks annually. About 11 to 18 teragrams of this nitrogen are chemically weathered in situ, thereby increasing the unmanaged (preindustrial) terrestrial nitrogen balance from 8 to 26%. These findings provide a global perspective to reconcile Earth's nitrogen budget, with implications for nutrient-driven controls over the terrestrial carbon sink. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  11. Convergent evidence for widespread rock nitrogen sources in Earth’s surface environment

    Science.gov (United States)

    Houlton, B. Z.; Morford, S. L.; Dahlgren, R. A.

    2018-04-01

    Nitrogen availability is a pivotal control on terrestrial carbon sequestration and global climate change. Historical and contemporary views assume that nitrogen enters Earth’s land-surface ecosystems from the atmosphere. Here we demonstrate that bedrock is a nitrogen source that rivals atmospheric nitrogen inputs across major sectors of the global terrestrial environment. Evidence drawn from the planet’s nitrogen balance, geochemical proxies, and our spatial weathering model reveal that ~19 to 31 teragrams of nitrogen are mobilized from near-surface rocks annually. About 11 to 18 teragrams of this nitrogen are chemically weathered in situ, thereby increasing the unmanaged (preindustrial) terrestrial nitrogen balance from 8 to 26%. These findings provide a global perspective to reconcile Earth’s nitrogen budget, with implications for nutrient-driven controls over the terrestrial carbon sink.

  12. Nitrogen-doped carbon monolith for alkaline supercapacitors and understanding nitrogen-induced redox transitions.

    Science.gov (United States)

    Wang, Da-Wei; Li, Feng; Yin, Li-Chang; Lu, Xu; Chen, Zhi-Gang; Gentle, Ian R; Lu, Gao Qing; Cheng, Hui-Ming

    2012-04-23

    A nitrogen-doped porous carbon monolith was synthesized as a pseudo-capacitive electrode for use in alkaline supercapacitors. Ammonia-assisted carbonization was used to dope the surface with nitrogen heteroatoms in a way that replaced carbon atoms but kept the oxygen content constant. Ammonia treatment expanded the micropore size-distributions and increased the specific surface area from 383 m(2) g(-1) to 679 m(2) g(-1). The nitrogen-containing porous carbon material showed a higher capacitance (246 F g(-1)) in comparison with the nitrogen-free one (186 F g(-1)). Ex situ electrochemical spectroscopy was used to investigate the evolution of the nitrogen-containing functional groups on the surface of the N-doped carbon electrodes in a three-electrode cell. In addition, first-principles calculations were explored regarding the electronic structures of different nitrogen groups to determine their relative redox potentials. We proposed possible redox reaction pathways based on the calculated redox affinity of different groups and surface analysis, which involved the reversible attachment/detachment of hydroxy groups between pyridone and pyridine. The oxidation of nitrogen atoms in pyridine was also suggested as a possible reaction pathway. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Exosomes: Mechanisms of Uptake

    Directory of Open Access Journals (Sweden)

    Kelly J. McKelvey

    2015-07-01

    Full Text Available Exosomes are 30–100 nm microvesicles which contain complex cellular signals of RNA, protein and lipids. Because of this, exosomes are implicated as having limitless therapeutic potential for the treatment of cancer, pregnancy complications, infections, and autoimmune diseases. To date we know a considerable amount about exosome biogenesis and secretion, but there is a paucity of data regarding the uptake of exosomes by immune and non-immune cell types (e.g., cancer cells and the internal signalling pathways by which these exosomes elicit a cellular response. Answering these questions is of paramount importance.

  14. Exosomes: Mechanisms of Uptake

    Directory of Open Access Journals (Sweden)

    Kelly J. McKelvey

    2015-07-01

    Full Text Available Exosomes are 30–100 nm microvesicles which contain complex cellular signals of RNA, protein and lipids. Because of this, exosomes are implicated as having limitless therapeutic potential for the treatment of cancer, pregnancy complications, infections, and autoimmune diseases. To date we know a considerable amount about exosome biogenesis and secretion, but there is a paucity of data regarding the uptake of exosomes by immune and non- immune cell types (e.g., cancer cells and the internal signalling pathways by which these exosomes elicit a cellular response. Answering these questions is of para‐ mount importance.

  15. Imaging analysis of direct alanine uptake by rice seedlings

    International Nuclear Information System (INIS)

    Nihei, Naoto; Masuda, Sayaka; Rai, Hiroki; Nakanishi, Tomoko M.

    2008-01-01

    We presented alanine, a kind of amino acids, uptake by a rice seedling to study the basic mechanism of the organic fertilizer effectiveness in organic farming. The rice grown in the culture solution containing alanine as a nitrogen source absorbed alanine approximately two times faster than that grown with NH 4 + from analysis of 14 C-alanine images by Imaging Plate method. It was suggested that the active transport ability of the rice seeding was induced in roots by existence of alanine in the rhizosphere. The alanine uptake images of the rice roots were acquired every 5 minutes successively by the real-time autoradiography system we developed. The analysis of the successive images showed that alanine uptake was not uniform throughout the root but especially active at the root tip. (author)

  16. Effect of different rates of nitrogen fertilizer on durum wheat (Triticum ...

    African Journals Online (AJOL)

    Dr Asefa

    2012-05-03

    May 3, 2012 ... The result showed that nitrogen rates and cultivars had significant effect on yield, yield related traits, nitrogen uptake ... cooking quality [8]. Durum wheat grain protein functionality can be influenced by N fertilization, particularly in the varieties of relatively with less gluten strength [9]. Information on the quality ...

  17. Temporal and spatial variation of nitrogen transformations in a coniferous forest soils.

    NARCIS (Netherlands)

    Laverman, A.M.; Zoomer, H.R.; van Verseveld, H.W.; Verhoef, H.A.

    2000-01-01

    Forest soils show a great degree of temporal and spatial variation of nitrogen mineralization. The aim of the present study was to explain temporal variation in nitrate leaching from a nitrogen-saturated coniferous forest soil by potential nitrification, mineralization rates and nitrate uptake by

  18. Temporal and spatial variation of nitrogen transformations in a coniferous soil.

    NARCIS (Netherlands)

    Laverman, A.M.; Zoomer, H.R.; van Verseveld, H.W.; Verhoef, H.A.

    2000-01-01

    Forest soils show a great degree of temporal and spatial variation of nitrogen mineralization. The aim of the present study was to explain temporal variation in nitrate leaching from a nitrogen-saturated coniferous forest soil by potential nitrification, mineralization rates and nitrate uptake by

  19. Nitrogen availability is a primary determinant of conifer mycorrhizas across complex environmental gradients

    Science.gov (United States)

    Filipa Cox; Nadia Barsoum; Erik A. Lilleskov; Martin I. Bidartondo

    2010-01-01

    Global environmental change has serious implications for functional biodiversity in temperate and boreal forests. Trees depend on mycorrhizal fungi for nutrient uptake, but predicted increases in nitrogen availability may alter fungal communities. To address a knowledge gap regarding the effects of nitrogen availability on mycorrhizal communities at large scales, we...

  20. Use efficiency of variable rate of nitrogen prescribed by optical sensor in corn

    Directory of Open Access Journals (Sweden)

    Jardes Bragagnolo

    2016-02-01

    Full Text Available ABSTRACT The efficiency of nitrogen fertilizer in corn is usually low, negatively affecting plant nutrition, the economic return, and the environment. In this context, a variable rate of nitrogen, prescribed by crop sensors, has been proposed as an alternative to the uniform rate of nitrogen traditionally used by farmers. This study tested the hypothesis that variable rate of nitrogen, prescribed by optical sensor, increases the nitrogen use efficiency and grain yield as compared to uniform rate of nitrogen. The following treatments were evaluated: 0; 70; 140; and 210 kg ha-1 under uniform rate of nitrogen, and 140 kg ha -1 under variable rate of nitrogen. The nitrogen source was urea applied on the soil surface using a distributor equipped with the crop sensor. In this study, the grain yield ranged from 10.2 to 15.5 Mg ha-1, with linear response to nitrogen rates. The variable rate of nitrogen increased by 11.8 and 32.6% the nitrogen uptake and nitrogen use efficiency, respectively, compared to the uniform rate of nitrogen. However, no significant increase in grain yield was observed, indicating that the major benefit of the variable rate of nitrogen was reducing the risk of environmental impact of fertilizer.

  1. Thyroid Uptake Measurement System

    International Nuclear Information System (INIS)

    Nguyen Duc Tuan; Nguyen Thi Bao My; Nguyen Van Sy

    2007-01-01

    The NED-UP.M7 is a complete thyroid uptake and analysis system specifically designed for nuclear medicine. Capable of performing a full range of studies this system provides fast, accurate results for Uptake Studies. The heart of the NED-UP.M7 is a microprocessor-controlled 2048 channel Compact Multi-Channel Analyzer, coupled to a 2 inch x 2 inch NaI(Tl) detector with a USB personal computer interface. The system offers simple, straight-forward operation using pre-programmed isotopes, and menudriven prompts to guide the user step by step through each procedure. The pre-programmed radionuclides include I-123, I-125, I-131, Tc-99m and Cs-137. The user-defined radionuclides also allow for isotope identification while the printer provides hard copy printouts for patient and department record keeping. The included software program running on PC (Windows XP-based) is a user friendly program with menudriven and graphic interface for easy controlling the system and managing measurement results of patient on Excel standard form. (author)

  2. Efficacy monitoring of in situ fuel bioremediation

    International Nuclear Information System (INIS)

    Mueller, J.; Borchert, S.; Heard, C.

    1996-01-01

    The wide-scale, multiple-purpose use of fossil fuels throughout the industrialized world has resulted in the inadvertent contamination of myriad environments. Given the scope and magnitude of these environmental contamination problems, bioremediation often represents the only practical and economically feasible solution. This is especially true when depth of contamination, magnitude of the problem, and nature of contaminated material preclude other remedial actions, short of the no-response alternative. From the perspective, the effective, safe and scientifically valid use of in situ bioremediation technologies requires cost-efficient and effective implementation strategies in combination with unequivocal approaches for monitoring efficacy of performance. Accordingly, with support from the SERDP program, the authors are field-testing advanced in situ bioremediation strategies and new approaches in efficacy monitoring that employ techniques instable carbon and nitrogen isotope biogeochemistry. One field demonstration has been initiated at the NEX site in Port Hueneme, CA (US Navy's National Test Site). The objectives are: (1) to use stable isotopes as a biogeochemical monitoring tool for in situ bioremediation of refined petroleum (i.e., BTEX), and (2) to use vertical groundwater circulation technology to effect in situ chemical containment and enhanced in situ bioremediation

  3. Effectiveness of liquid organic-nitrogen fertilizer in enhancing ...

    African Journals Online (AJOL)

    The ever increasing price of nitrogenous (N) fertilizers coupled with the deleterious effects of imbalanced N fertilizers on the environment necessitates the enhancement of N use efficiency of plants. The objectives of this study were to: (1) Evaluate the uptake of selected nutrients due to application of liquid organic-N ...

  4. Enhancing the biological nitrogen fixation of leguminous crops ...

    African Journals Online (AJOL)

    Legumes have the ability to establish a symbiotic interaction with soil bacteria, collectively termed as rhizobia. These bacteria can enhance growth and development of associated crops by transferring atmospheric nitrogen into a form that is available for plant growth or by improving nutrient uptake through modulation of ...

  5. Remote sensing of nitrogen and water stress in wheat

    NARCIS (Netherlands)

    Tilling, A.K.; O'Leary, G.J.; Ferwerda, J.G.; Jones, S.D.; Fitzgerald, G.J.; Rodriguez, D.; Belford, R.

    2007-01-01

    Nitrogen (N) is the largest agricultural input in many Australian cropping systems and applying the right amount of N in the right place at the right physiological stage is a significant challenge for wheat growers. Optimizing N uptake could reduce input costs and minimize potential off-site

  6. Comparison of chromium and nickel uptake of plants grown in different soils

    Energy Technology Data Exchange (ETDEWEB)

    Vago, I. [University of Agriculture, Faculty of Agronomy, H-4015 Debrecen, P.O. Box 36 (Hungary); Gyoeri, Z. [University of Agriculture, Faculty of Agronomy, H-4015 Debrecen, P.O. Box 36 (Hungary); Loch, J. [University of Agriculture, Faculty of Agronomy, H-4015 Debrecen, P.O. Box 36 (Hungary)

    1996-03-01

    The chromium and nickel uptake of ryegrass has been examined in pot experiments in extremely different soils, poor sandy and fertile black chernozem. The effect of calcium carbonate doses and nitrogen supply on heavy metal uptake of the plant has been studied for chromium and nickel loadings (0-100 mg/kg Cr{sup 3+} or Ni{sup 2+}) applied as inorganic salts. The ability to uptake Cr{sup 3+} and Ni{sup 2+} differs significantly and is highly affected by the characteristics of soils, and depends on the metal investigated. The heavy metal uptake of the plant differs significantly in acid, colloid deficient sandy soils; while artificial chromium contamination did not modify the dry-matter production in the pots in either soil, a large quantity of nickel reduced the yields significantly. Nitrogen application did not change significantly the uptake of heavy metals. Lime application reduced the Ni{sup 2+} uptake of plants considerably, especially in sandy soil. In case of a calcium carbonate addition the dry-matter production of the plant was not affected by nickel. In chernozem soil the effect of lime application - i.e., the reduction of nickel uptake - was of a lesser degree. The significantly lesser Cr{sup 3+} uptake was further limited by a calcium carbonate application for both soils studied. A graphic presentation of these effects is given. (orig.). With 3 figs., 3 tabs.

  7. Kinetic Uptake Studies of Powdered Materials in Solution

    Directory of Open Access Journals (Sweden)

    Mohamed H. Mohamed

    2015-06-01

    Full Text Available Challenges exist for the study of time dependent sorption processes for heterogeneous systems, especially in the case of dispersed nanomaterials in solvents or solutions because they are not well suited to conventional batch kinetic experiments. In this study, a comparison of batch versus a one-pot setup in two variable configurations was evaluated for the study of uptake kinetics in heterogeneous (solid/solution systems: (i conventional batch method; (ii one-pot system with dispersed adsorbent in solution with a semi-permeable barrier (filter paper or dialysis tubing for in situ sampling; and (iii one-pot system with an adsorbent confined in a semi-permeable barrier (dialysis tubing or filter paper barrier with ex situ sampling. The sorbent systems evaluated herein include several cyclodextrin-based polyurethane materials with two types of phenolic dyes: p-nitrophenol and phenolphthalein. The one-pot kinetics method with in situ (Method ii or ex situ (Method iii sampling described herein offers significant advantages for the study of heterogeneous sorption kinetics of highly dispersed sorbent materials with particles sizes across a range of dimensions from the micron to nanometer scale. The method described herein will contribute positively to the development of advanced studies for heterogeneous sorption processes where an assessment of the relative uptake properties is required at different experimental conditions. The results of this study will be advantageous for the study of nanomaterials with significant benefits over batch kinetic studies for a wide range of heterogeneous sorption processes.

  8. Nitrogen fixation and induction of pseudo-nodules in grass

    International Nuclear Information System (INIS)

    Rasul, G.; Hassan, U.; Mehnaz, S.; Malik, K.A.

    1993-01-01

    The rice grown nitrogen depleted saline sols showed higher values for in-situ ARA. Isolations of N/sub 2/ fixing bacteria were carried out on soil Azotobacter was observed in plant rhizosphere. The 2,4-D (0.5 and 1 ppm) with diazo trophic bacteria induced nodule like structure on the wheat roots. The bacteria were found in nodules in the form of micro colonies or bacterial aggregates which were responsible for nitrogen fixation providing optimum 02 concentrations was incorporations /sup 15/N dilution data indicated that 125-46.5% atmosphere N was incorporated in nitrogen pool of inoculated plants. (author)

  9. The Impact of Nitrogen Limitation and Mycorrhizal Symbiosis on Aspen Tree Growth and Development

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Bich Thi Ngoc [Univ. of Alabama, Huntsville, AL (United States)

    2014-08-18

    Nitrogen deficiency is the most common and widespread nutritional deficiency affecting plants worldwide. Ectromycorrhizal symbiosis involves the beneficial interaction of plants with soil fungi and plays a critical role in nutrient cycling, including the uptake of nitrogen from the environment. The main goal of this study is to understand how limiting nitrogen in the presence or absence of an ectomycorrhizal fungi, Laccaria bicolor, affects the health of aspen trees, Populus temuloides.

  10. Exogenous Glycine Nitrogen Enhances Accumulation of Glycosylated Flavonoids and Antioxidant Activity in Lettuce (Lactuca sativa L.)

    OpenAIRE

    Xiao Yang; Xiaoxian Cui; Xiaoxian Cui; Li Zhao; Doudou Guo; Lei Feng; Shiwei Wei; Chao Zhao; Chao Zhao; Danfeng Huang

    2017-01-01

    Glycine, the simplest amino acid in nature and one of the most abundant free amino acids in soil, is regarded as a model nutrient in organic nitrogen studies. To date, many studies have focused on the uptake, metabolism and distribution of organic nitrogen in plants, but few have investigated the nutritional performance of plants supplied with organic nitrogen. Lettuce (Lactuca sativa L.), one of the most widely consumed leafy vegetables worldwide, is a significant source of antioxidants and ...

  11. Occurrence and distribution of nitrogen-scavenging bacteria in marine environment

    OpenAIRE

    Sugahara, Isao; Kimura, Toshio; Hayashi, Koichiro

    1987-01-01

    The occurrence and distribution nitrogen-scavenging bacteria in the water of coastal and oceanic of Japan were studied during the Seisui-Maru cruises from 1986 to 1987. Nitroben-scavenging bacteria in the water usually occurred at the level of 10-104 cfu/ml.This value was almost comparable to that of aerobic heterotrophic bacteria. It seems that nitrogen-scavenging bacteria play an important role in the efficient uptake of low levels of nitrogenous compounds in marine enviroment.

  12. Nitrogen retention in river corridors: European perspective

    Energy Technology Data Exchange (ETDEWEB)

    Haycock, N [Dept. of Agriculture and Water Management, Silsoe College, Cranfield Institute of Technology (United Kingdom); Pinay, G [CERR/CNRS, Toulouse (France); Walker, Charles [SBEG, Inst. of Ecology, Lund Univ. (Sweden)

    1993-01-01

    The problem of nitrogen pollution in European surface- and groundwaters has become a focus of recent European and Scandinavian directives, with legislation calling for a 50% reduction of N losses by the years 1995 and 2000, respectively. This paper provides a conceptual framework upon which management strategies to reduce losses of diffuse nitrogen pollution to surface waters may be based. The control of nitrogen pollution may take place through an increase in the complexity of the landscape, not throughout the catchment area, but rather in specific zones, the river corridor in particular. Within river corridors, riparian areas have been recognized globally for their value as nutrient removal ''buffer systems''. Studies have identified vegetation uptake and microbial denitrification as the primary mechanisms responsible for N removal in these systems. For these processes to function optimally on an annual basis, both vegetation and water regime must be managed. The establishment and management of riparian buffer zones in suitable places within river corridors, will provide a stable and sustainable water-protection function. This will complement future nitrogen input control strategies, needed for both the long-term protection of groundwater and surface waters in Europe as a whole, and for the proposed 50% reduction in nitrogen loading to the Baltic and North Sea coastal waters by the turn of the century. 52 refs, 5 figs

  13. Continuous ammonium enrichment of a woodland stream: uptake kinetics, leaf decomposition, and nitrification

    Energy Technology Data Exchange (ETDEWEB)

    Newbold, J D; Elwood, J W; Schulze, M S; Stark, R W; Barmeier, J C

    1983-01-01

    In order to test for nitrogen limitation and examine ammonium uptake by stream sediments, ammonium hydroxide was added continuously at concentrations averaging 100 /sup +/gl/sup -1/ for 70 days to a second-order reach of Walker Branch, an undisturbed woodland stream in Tennessee. Ammonium uptake during the first 4 h of addition corresponded to adsorption kinetics rather than to first-order uptake or to Michaelis-Menten kinetics. However, the calculated adsorption partition coefficient was two to four orders of magnitude greater than values reported for physical adsorption of ammonium, suggesting that the uptake was largely biotic. Mass balance indicated that the uptake of ammonium from the water could be accounted for by increased nitrogen content in benthic organic detritus. Nitrification, inferred from longitudinal gradients in NO/sub 3/, began soon after enrichment and increased dramatically near the end of the experiment. Both ammonium and nitrate concentrations dropped quickly to near background levels when input ceased, indicating little desorption or nitrification of excess nitrogen stored in the reach. There was no evidence of nitrogen limitation as measured by weight loss, oxygen consumption, phosphorus content, and macroinvertebrate density of red oak leaf packs, or by chlorophyll content and aufwuchs biomass on plexiglass slides. A continuous phosphorus enrichment 1 year earlier had demonstrated phosphorus limitation in Walker Branch. 38 references, 6 figures, 3 tables.

  14. The fate of fertilizer nitrogen in winter wheat under different water and nitrogen levels

    International Nuclear Information System (INIS)

    Li Shijuan; Zhou Dianxi; Lan Linwang

    2002-01-01

    N uptake and the fate of fertilizer N were studied in the field under different water and nitrogen levels with 15 N technique. Results showed that (1) the total N uptake of economical N treatment under saving irrigation was higher than that under conventional irrigation. Under saving irrigation the total N uptake of conventional N was higher than that of economical N treatment, yet the NHI decreased; (2) compared with saving irrigation, the N loss of conventional irrigation increased and NUE and soil residue decreased. On the same water condition the NUE and soil residue of conventional N treatment was lower than that of economical treatment, and N loss increased; (3) for the same fertilizer amount, the loss of N applied all as basal fertilizer is lower than that of part as basal and part as top-dressing treatment

  15. Marine nitrogen cycle

    Digital Repository Service at National Institute of Oceanography (India)

    Naqvi, S.W.A.

    ) such as the Marine nitrogen cycle The marine nitrogen cycle. ‘X’ and ‘Y’ are intra-cellular intermediates that do not accumulate in water column. (Source: Codispoti et al., 2001) Page 1 of 3Marine nitrogen cycle - Encyclopedia of Earth 11/20/2006http://www... and nitrous oxide budgets: Moving targets as we enter the anthropocene?, Sci. Mar., 65, 85-105, 2001. Page 2 of 3Marine nitrogen cycle - Encyclopedia of Earth 11/20/2006http://www.eoearth.org/article/Marine_nitrogen_cycle square6 Gruber, N.: The dynamics...

  16. Dynamics of dissolved and extractable organic nitrogen upon soil amendment with crop residues

    NARCIS (Netherlands)

    Ros, G.H.; Hoffland, E.

    2010-01-01

    Dissolved organic nitrogen (DON) is increasingly recognized as a pivotal pool in the soil nitrogen (N) cycle. Numerous devices and sampling procedures have been used to estimate its size, varying from in situ collection of soil solution to extraction of dried soil with salt solutions. Extractable

  17. Depletion of carbohydrate reserves limits nitrate uptake during early regrowth in Lolium perenne L.

    Czech Academy of Sciences Publication Activity Database

    Guo, Q.; Turnbull, M.; Song, J.; Roche, J.; Novák, Ondřej; Späth, J.; Jameson, P. E.; Love, J.

    2017-01-01

    Roč. 68, č. 7 (2017), s. 1569-1583 ISSN 0022-0957 R&D Projects: GA ČR(CZ) GA17-06613S Institutional support: RVO:61389030 Keywords : Carbohydrate * Carbon * Cytokinin * Fructan * Lolium perenne * Nitrate transporter (NRT) * Nitrate uptake * Nitrogen * Nitrogen use efficiency (NUE) * Perennial ryegrass Subject RIV: EF - Botanics OBOR OECD: Plant sciences, botany Impact factor: 5.830, year: 2016

  18. Soil nitrogen availability in the open steppe with Stipa tenacissima

    Science.gov (United States)

    Novosadova, Irena; Damian Ruiz Sinoga, Jose; Záhora, Jaroslav

    2010-05-01

    functioning, particularly in Mediterranean areas, where nutrient availability, mainly nitrogen and phosphorous, represents a limiting factor (Sardans et al., 2005) together with water availability. Soil N availability has been found to affect plant water use efficiency (Sardans et al., 2008a). This strong link between N availability and water use efficiency makes particularly important the understanding of factors affecting soil N availability in Mediterranean ecosystems in view of the future predicted increasing drought in this area. Changes in the soil nitrogen availability in the open steppe with S. tenacissima were monitored over a two distinct period of time during the years 2008 and 2009 at a field site in semi-arid south-eastern Spain (Novosádová et al., 2010). The availability of ammonia-nitrogen and nitrate nitrogen was estimated in situ according to Binkley at Matson (1982) by the trapping of mineral N into the ion exchange resin inserted into special cover. The availability of soil ammonia-N as well as the availability of nitrate-N were in the 2008 year significantly influenced by the addition of different substrate (only 38% of control after the cellulose addition and 176% of control after the raw silk addition). In the following 2009 year was the N availability probably due to favorable soil moisture nearly the same in all experimental variants. The availability of ammonia-N was, in general, higher than the availability of nitrate-N, but the differences were less noticeable in 2008 year. It can be concluded, that the microbial competition for available nitrogen is very high and spatially and/or temporary significantly different.

  19. QTL and QTL x environment effects on agronomic and nitrogen acquisition traits in rice.

    Science.gov (United States)

    Senthilvel, Senapathy; Vinod, Kunnummal Kurungara; Malarvizhi, Palaniappan; Maheswaran, Marappa

    2008-09-01

    Agricultural environments deteriorate due to excess nitrogen application. Breeding for low nitrogen responsive genotypes can reduce soil nitrogen input. Rice genotypes respond variably to soil available nitrogen. The present study attempted quantification of genotype x nitrogen level interaction and mapping of quantitative trait loci (QTLs) associated with nitrogen use efficiency (NUE) and other associated agronomic traits. Twelve parameters were observed across a set of 82 double haploid (DH) lines derived from IR64/Azucena. Three nitrogen regimes namely, native (0 kg/ha; no nitrogen applied), optimum (100 kg/ha) and high (200 kg/ha) replicated thrice were the environments. The parents and DH lines were significantly varying for all traits under different nitrogen regimes. All traits except plant height recorded significant genotype x environment interaction. Individual plant yield was positively correlated with nitrogen use efficiency and nitrogen uptake. Sixteen QTLs were detected by composite interval mapping. Eleven QTLs showed significant QTL x environment interactions. On chromosome 3, seven QTLs were detected associated with nitrogen use, plant yield and associated traits. A QTL region between markers RZ678, RZ574 and RZ284 was associated with nitrogen use and yield. This chromosomal region was enriched with expressed gene sequences of known key nitrogen assimilation genes.

  20. Assessment of free-living nitrogen fixing microorganisms for commercial nitrogen fixation. [economic analysis of ammonia production

    Science.gov (United States)

    Stokes, B. O.; Wallace, C. J.

    1978-01-01

    Ammonia production by Klebsiella pneumoniae is not economical with present strains and improving nitrogen fixation to its theoretical limits in this organism is not sufficient to achieve economic viability. Because the value of both the hydrogen produced by this organism and the methane value of the carbon source required greatly exceed the value of the ammonia formed, ammonia (fixed nitrogen) should be considered the by-product. The production of hydrogen by KLEBSIELLA or other anaerobic nitrogen fixers should receive additional study, because the activity of nitrogenase offers a significant improvement in hydrogen production. The production of fixed nitrogen in the form of cell mass by Azotobacter is also uneconomical and the methane value of the carbon substrate exceeds the value of the nitrogen fixed. Parametric studies indicate that as efficiencies approach the theoretical limits the economics may become competitive. The use of nif-derepressed microorganisms, particularly blue-green algae, may have significant potential for in situ fertilization in the environment.

  1. Assimilation of diazotrophic nitrogen into pelagic food webs.

    Directory of Open Access Journals (Sweden)

    Ryan J Woodland

    Full Text Available The fate of diazotrophic nitrogen (N(D fixed by planktonic cyanobacteria in pelagic food webs remains unresolved, particularly for toxic cyanophytes that are selectively avoided by most herbivorous zooplankton. Current theory suggests that N(D fixed during cyanobacterial blooms can enter planktonic food webs contemporaneously with peak bloom biomass via direct grazing of zooplankton on cyanobacteria or via the uptake of bioavailable N(D (exuded from viable cyanobacterial cells by palatable phytoplankton or microbial consortia. Alternatively, N(D can enter planktonic food webs post-bloom following the remineralization of bloom detritus. Although the relative contribution of these processes to planktonic nutrient cycles is unknown, we hypothesized that assimilation of bioavailable N(D (e.g., nitrate, ammonium by palatable phytoplankton and subsequent grazing by zooplankton (either during or after the cyanobacterial bloom would be the primary pathway by which N(D was incorporated into the planktonic food web. Instead, in situ stable isotope measurements and grazing experiments clearly documented that the assimilation of N(D by zooplankton outpaced assimilation by palatable phytoplankton during a bloom of toxic Nodularia spumigena Mertens. We identified two distinct temporal phases in the trophic transfer of N(D from N. spumigena to the plankton community. The first phase was a highly dynamic transfer of N(D to zooplankton with rates that covaried with bloom biomass while bypassing other phytoplankton taxa; a trophic transfer that we infer was routed through bloom-associated bacteria. The second phase was a slowly accelerating assimilation of the dissolved-N(D pool by phytoplankton that was decoupled from contemporaneous variability in N. spumigena concentrations. These findings provide empirical evidence that N(D can be assimilated and transferred rapidly throughout natural plankton communities and yield insights into the specific processes

  2. Assimilation of diazotrophic nitrogen into pelagic food webs.

    Science.gov (United States)

    Woodland, Ryan J; Holland, Daryl P; Beardall, John; Smith, Jonathan; Scicluna, Todd; Cook, Perran L M

    2013-01-01

    The fate of diazotrophic nitrogen (N(D)) fixed by planktonic cyanobacteria in pelagic food webs remains unresolved, particularly for toxic cyanophytes that are selectively avoided by most herbivorous zooplankton. Current theory suggests that N(D) fixed during cyanobacterial blooms can enter planktonic food webs contemporaneously with peak bloom biomass via direct grazing of zooplankton on cyanobacteria or via the uptake of bioavailable N(D) (exuded from viable cyanobacterial cells) by palatable phytoplankton or microbial consortia. Alternatively, N(D) can enter planktonic food webs post-bloom following the remineralization of bloom detritus. Although the relative contribution of these processes to planktonic nutrient cycles is unknown, we hypothesized that assimilation of bioavailable N(D) (e.g., nitrate, ammonium) by palatable phytoplankton and subsequent grazing by zooplankton (either during or after the cyanobacterial bloom) would be the primary pathway by which N(D) was incorporated into the planktonic food web. Instead, in situ stable isotope measurements and grazing experiments clearly documented that the assimilation of N(D) by zooplankton outpaced assimilation by palatable phytoplankton during a bloom of toxic Nodularia spumigena Mertens. We identified two distinct temporal phases in the trophic transfer of N(D) from N. spumigena to the plankton community. The first phase was a highly dynamic transfer of N(D) to zooplankton with rates that covaried with bloom biomass while bypassing other phytoplankton taxa; a trophic transfer that we infer was routed through bloom-associated bacteria. The second phase was a slowly accelerating assimilation of the dissolved-N(D) pool by phytoplankton that was decoupled from contemporaneous variability in N. spumigena concentrations. These findings provide empirical evidence that N(D) can be assimilated and transferred rapidly throughout natural plankton communities and yield insights into the specific processes underlying

  3. Representing leaf and root physiological traits in CLM improves global carbon and nitrogen cycling predictions

    Science.gov (United States)

    Ghimire, Bardan; Riley, William J.; Koven, Charles D.; Mu, Mingquan; Randerson, James T.

    2016-06-01

    In many ecosystems, nitrogen is the most limiting nutrient for plant growth and productivity. However, current Earth System Models (ESMs) do not mechanistically represent functional nitrogen allocation for photosynthesis or the linkage between nitrogen uptake and root traits. The current version of CLM (4.5) links nitrogen availability and plant productivity via (1) an instantaneous downregulation of potential photosynthesis rates based on soil mineral nitrogen availability, and (2) apportionment of soil nitrogen between plants and competing nitrogen consumers assumed to be proportional to their relative N demands. However, plants do not photosynthesize at potential rates and then downregulate; instead photosynthesis rates are governed by nitrogen that has been allocated to the physiological processes underpinning photosynthesis. Furthermore, the role of plant roots in nutrient acquisition has also been largely ignored in ESMs. We therefore present a new plant nitrogen model for CLM4.5 with (1) improved representations of linkages between leaf nitrogen and plant productivity based on observed relationships in a global plant trait database and (2) plant nitrogen uptake based on root-scale Michaelis-Menten uptake kinetics. Our model improvements led to a global bias reduction in GPP, LAI, and biomass of 70%, 11%, and 49%, respectively. Furthermore, water use efficiency predictions were improved conceptually, qualitatively, and in magnitude. The new model's GPP responses to nitrogen deposition, CO2 fertilization, and climate also differed from the baseline model. The mechanistic representation of leaf-level nitrogen allocation and a theoretically consistent treatment of competition with belowground consumers led to overall improvements in global carbon cycling predictions.

  4. [Effects of nitrogen and irrigation water application on yield, water and nitrogen utilization and soil nitrate nitrogen accumulation in summer cotton].

    Science.gov (United States)

    Si, Zhuan Yun; Gao, Yang; Shen, Xiao Jun; Liu, Hao; Gong, Xue Wen; Duan, Ai Wang

    2017-12-01

    NO 3 - -N accumulation layer moved downward. By comprehensively considering above-ground biomass, seed cotton yield, water and nitrogen uptake and utilization, and soil NO 3 - -N accumulation in the soil profile, the treatment N 3 I 1 could be recommended as the optimal water and nitrogen application pattern for summer cotton production in the experimental region.

  5. Radioiodine uptake measurements in thyroid

    International Nuclear Information System (INIS)

    Kadireshn, A.; Kapur, S.C.; Samuel, J.R.; Mahajan, M.K.

    1988-01-01

    Evaluation of thyroid function can be carried out by measuring the uptake of orally administered radioactive iodine. The results of the thyroid uptake measurements for the period 1982-1987 in Christian Medical College, Ludhiana are presented here. About 3000 patients were screened during the analysis period. (author)

  6. Aquaporins and root water uptake

    Science.gov (United States)

    Water is one of the most critical resources limiting plant growth and crop productivity, and root water uptake is an important aspect of plant physiology governing plant water use and stress tolerance. Pathways of root water uptake are complex and are affected by root structure and physiological res...

  7. Uptake of nuclides by plants

    International Nuclear Information System (INIS)

    Greger, Maria

    2004-04-01

    This review on plant uptake of elements has been prepared to demonstrate how plants take up different elements. The work discusses the nutrient elements, as well as the general uptake and translocation in plants, both via roots and by foliar absorption. Knowledge of the uptake by the various elements within the periodic system is then reviewed. The work also discusses transfer factors (TF) as well as difficulties using TF to understand the uptake by plants. The review also focuses on species differences. Knowledge necessary to understand and calculate plant influence on radionuclide recirculation in the environment is discussed, in which the plant uptake of a specific nuclide and the fate of that nuclide in the plant must be understood. Plants themselves determine the uptake, the soil/sediment determines the availability of the nuclides and the nuclides themselves can interact with each other, which also influences the uptake. Consequently, it is not possible to predict the nuclide uptake in plants by only analysing the nuclide concentration of the soil/substrate

  8. Uptake of nuclides by plants

    Energy Technology Data Exchange (ETDEWEB)

    Greger, Maria [Stockholm Univ. (Sweden). Dept. of Botany

    2004-04-01

    This review on plant uptake of elements has been prepared to demonstrate how plants take up different elements. The work discusses the nutrient elements, as well as the general uptake and translocation in plants, both via roots and by foliar absorption. Knowledge of the uptake by the various elements within the periodic system is then reviewed. The work also discusses transfer factors (TF) as well as difficulties using TF to understand the uptake by plants. The review also focuses on species differences. Knowledge necessary to understand and calculate plant influence on radionuclide recirculation in the environment is discussed, in which the plant uptake of a specific nuclide and the fate of that nuclide in the plant must be understood. Plants themselves determine the uptake, the soil/sediment determines the availability of the nuclides and the nuclides themselves can interact with each other, which also influences the uptake. Consequently, it is not possible to predict the nuclide uptake in plants by only analysing the nuclide concentration of the soil/substrate.

  9. Ammonia Nitrogen Added to Diets Deficient in Dispensable Amino Acid Nitrogen Is Poorly Utilized for Urea Production in Growing Pigs.

    Science.gov (United States)

    Mansilla, Wilfredo D; Silva, Kayla E; Zhu, Cuilan L; Nyachoti, Charles M; Htoo, John K; Cant, John P; de Lange, Cornelis Fm

    2017-12-01

    Background: Including ammonia in low-crude protein (CP) diets deficient in dispensable amino acid (DAAs) increases nitrogen retention in growing pigs. Objective: We investigated the absorption and metabolism of dietary ammonia nitrogen in the portal-drained viscera (PDV) and liver of pigs fed a diet deficient in DAA nitrogen. Methods: Eight pigs with an initial mean ± SD body weight (BW) of 26.5 ± 1.4 kg were surgically fitted with 4 catheters each (portal, hepatic and mesenteric veins, and carotid artery). The pigs were fed (2.8 × 191 kcal/kg BW 0.60 ), for 7 d and every 8 h, a diet deficient in DAA nitrogen supplemented with increasing amounts of ammonia nitrogen (CP: 7.76%, 9.27%, and 10.77%; indispensable amino acid nitrogen:total nitrogen ratio: 0.71, 0.59, and 0.50 for control and low- and high-ammonia diets, respectively). The treatment sequence was based on a Latin square design with 3 consecutive periods. On the last day of each period, blood flows in the portal and hepatic veins were determined with a continuous infusion of ρ-amino hippuric acid into the mesenteric vein. Serial blood samples were taken to determine ammonia and urea nitrogen concentration. Net balances of ammonia and urea nitrogen were calculated for the PDV and liver. Results: Cumulative (8 h) ammonia nitrogen appearance in the portal vein increased ( P ≤ 0.05) with ammonia intake (433, 958, and 1629 ± 60 mg ammonia nitrogen/meal for control and low- and high-ammonia diets, respectively). The cumulative hepatic uptake of ammonia nitrogen increased ( P ≤ 0.05) with ammonia nitrogen supply. The cumulative urea nitrogen appearance in the hepatic vein tended to increase ( P ≤ 0.10) only in high-ammonia treatment (-92.5, -59.4, and 209.7 ± 92 mg urea nitrogen/meal for control and low- and high-ammonia diets, respectively) and, relative to the control diet, represented -6.0% and 11% of ammonia nitrogen intake. Conclusion: Dietary ammonia nitrogen is poorly utilized for urea

  10. Cadmium uptake by plants

    Energy Technology Data Exchange (ETDEWEB)

    Haghiri, F.

    1973-01-01

    Absorption of /sup 115m/Cd by soybean (Gylcine max l.) plants via foliar and root systems and translocation into the seed was determined. The uptake of /sup 115m/Cd by soybeans via the root system was more efficient than that of the foliar placement. Growth and Cd concentrations of soybean and wheat (Triticum aestivum l.) tops were influenced by soil-applied Cd. In both crops, the Cd concentration of plant tops increased while yield decreased with increasing levels of applied Cd. Cadmium toxicitiy began to occur in both crops at the lowest level of soil applied Cd (2.5 ppM). With soybean plants, Cd toxicity symptoms resembled fe chlorosis. For wheat plants there were no visual symptoms other than the studied growth. The relative concentration of Cd found in several vegetable crops varied depending on the plant species. The relative Cd concentration in descending order for various vegetables was lettuce (Lactuca sativa l.) > radish top (Raphanus sativus l.) > celery stalk (Apium graveolens l.) > celery leaves greater than or equal to green pepper (Capsicum frutescens l.) > radish roots.

  11. Nitrogen requirements of commercial wine yeast strains during fermentation of a synthetic grape must.

    Science.gov (United States)

    Gutiérrez, Alicia; Chiva, Rosana; Sancho, Marta; Beltran, Gemma; Arroyo-López, Francisco Noé; Guillamon, José Manuel

    2012-08-01

    Nitrogen deficiencies in grape musts are one of the main causes of stuck or sluggish wine fermentations. Currently, the most common method for dealing with nitrogen-deficient fermentations is adding supplementary nitrogen (usually ammonium phosphate). However, it is important to know the specific nitrogen requirement of each strain, to avoid excessive addition that can lead to microbial instability and ethyl carbamate accumulation. In this study, we aimed to determine the effect of increasing nitrogen concentrations of three different nitrogen sources on growth and fermentation performance in four industrial wine yeast strains. This task was carried out using statistical modeling techniques. The strains PDM and RVA showed higher growth-rate and maximum population size and consumed nitrogen much more quickly than strains ARM and TTA. Likewise, the strains PDM and RVA were also the greatest nitrogen demanders. Thus, we can conclude that these differences in nitrogen demand positively correlated with higher growth rate and higher nitrogen uptake rate. The most direct effect of employing an adequate nitrogen concentration is the increase in biomass, which involves a higher fermentation rate. However, the impact of nitrogen on fermentation rate is not exclusively due to the increase in biomass because the strain TTA, which showed the worst growth behavior, had the best fermentation activity. Some strains may adapt a strategy whereby fewer cells with higher metabolic activity are produced. Regarding the nitrogen source used, all the strains showed the better and worse fermentation performance with arginine and ammonium, respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Developments in nitrogen generators

    International Nuclear Information System (INIS)

    Ayres, C.L.; Abrardo, J.M.; Himmelberger, L.M.

    1984-01-01

    Three process cycles for the production of nitrogen by the cryogenic separation of air are described in detail. These cycles are: (1) a waste expander cycle; (2) an air expander cycle; and (3) a cycle for producing large quantities of gaseous nitrogen. Each cycle has distinct advantages for various production ranges and delivery pressures. A dicussion of key parameters that must be considered when selecting a cycle to meet specific product requirements is presented. The importance of high plant reliability and a dependable liquid nitrogen back up system is also presented. Lastly, a discussion of plant safety dealing with the hazards of nitrogen, enriched oxygen, and hydrocarbons present in the air is reviewed

  13. Atmospheric nitrogen dioxide and northern plants

    Energy Technology Data Exchange (ETDEWEB)

    Aurela, A; Punkkinen, R

    1981-01-01

    Convincing quantitative data have recently been published about the uptake of atmospheric NO/sub 2/ by certain plants. Several qualitative pieces of evidence were found suggesting similar ability in northern plants. The volume fraction of NO/sub 2/ in the air, Phi, was measured at Kevo (70/sup 0/N, 27/sup 0/E). The Saltzman method was used, with a continuously recording detector, especially developed for measurements below the usual analytical limit of this method (0.005 ppm). The systematic error of Phi was estimated to be less than 50%. In general, Phi did not vary much with time. However, when the recorder of the atmospheric electric field at the adjacent Meteorological Station of Kevo once rose up to 4 times the normal value, the Phi-curve simultaneously rose momentarily. By using the measured value of anti-Phi, the annual uptake of NO/sub 2/-nitrogen by plants in the region of Kevo was estimated to be about 0.1 g(N)m/sup -2/ for a canopy of pines and lichens, and about 0.001 g(N)m/sup -2/ for plants at the tops of low mountains. In terms of dry weight of lichens, the uptake rate would be of the order of 0.1 ..mu..g(N)h/sup -1/ (g dry weight)/sup -1/, based on independent measurements. These amount are of the same order of magnitude as the yields of biological nitrogen fixation by lichens in corresponding conditions. A direct experimental study of the uptake of atmospheric NO/sub 2/ by northern plants seems very desirable and readily feasible.

  14. Effect of gamma radiation on the nitrogen metabolism of Paecilomyces Violacea

    International Nuclear Information System (INIS)

    Salama, A.H.; Nadia, M.; Elzawahry, Y.A.; Abo Elkhair, I.A.

    1989-01-01

    Quantitative variabilities could be noticed in the nitrogen utilization and mycelial content of mats arising from gamma irradiated and non-irradiated Inocula of P.Violacea. The two lowest doses, 0.1 and 0.25 KGy, showed an increase in nitrate uptake and nitrogen utilization more than control by 7.43 and 15.61% for nitrate uptake and 8.33 and 14.89 for nitrogen utilization respectively, while the higher doses (0.5 up to 3.0 KGy) were inhibitory to the above parameters and also to protein synthesis. The chemical changes in the composition of fungal mats reveal that the peptide-N was the highest in amount as compared with the other nitrogen fractions. The protein-N was second in rank of quantity followed by the amino-N, while the nitrate-N was the least in amount compared to other nitrogen fractions at all radiation treatments

  15. Factors influencing the in vitro uptake of mercury vapour in blood

    Energy Technology Data Exchange (ETDEWEB)

    Kudsk, F.N.

    1969-01-01

    The influence of a number of factors on the in vitro uptake of mercury vapour in blood has been investigated in order to clarify the mechanism by which mercury is oxidized in blood. The rate of mercury uptake in blood in a pure oxygen atmosphere is moderately increased, but somewhat decreased in a nitrogen atmosphere when compared with the rate of uptake in an atmospheric air phase. Increasing concentrations of methylene blue induce a very pronounced acceleration of the rate of mercury uptake in blood up to a maximum of about 10 times the normal uptake in an atmospheric air phase. Menadione shows a similar, but even more pronounced effect. The menadione-stimulated uptake is markedly inhibited by low concentrations of ethyl alcohol. Concentrations of potassium cyanide from 1/8 x 10/sup -3/ to 4 x 10/sup -3/ M cause a progressive inhibition of the mercury uptake in the blood up to a maximum of about 60%, which is very similar to the effect produced by ethyl alcohol. The investigations point to hydrogen peroxide and oxidized glutathione as agents of importance in the oxidation and uptake of mercury vapour in blood. The way in which ethyl alcohol inhibits the uptake is still unknown. Some possible mechanisms are discussed. 24 references, 4 figures, 3 tables.

  16. In situ growth of p and n-type graphene thin films and diodes by pulsed laser deposition

    KAUST Repository

    Sarath Kumar, S. R.; Nayak, Pradipta K.; Hedhili, Mohamed N.; Khan, M. A.; Alshareef, Husam N.

    2013-01-01

    We report the in situ growth of p and n-type graphene thin films by ultraviolet pulsed laser deposition in the presence of argon and nitrogen, respectively. Electron microscopy and Raman studies confirmed the growth, while temperature dependent

  17. Spectral measurements at different spatial scales in potato: relating leaf, plant and canopy nitrogen status

    Science.gov (United States)

    Jongschaap, Raymond E. E.; Booij, Remmie

    2004-09-01

    Chlorophyll contents in vegetation depend on soil nitrogen availability and on crop nitrogen uptake, which are important management factors in arable farming. Crop nitrogen uptake is important, as nitrogen is needed for chlorophyll formation, which is important for photosynthesis, i.e. the conversion of absorbed radiance into plant biomass. The objective of this study was to estimate leaf and canopy nitrogen contents by near and remote sensing observations and to link observations at leaf, plant and canopy level. A theoretical base is presented for scaling-up leaf optical properties to whole plants and crops, by linking different optical recording techniques at leaf, plant and canopy levels through the integration of vertical nitrogen distribution. Field data come from potato experiments in The Netherlands in 1997 and 1998, comprising two potato varieties: Eersteling and Bintje, receiving similar nitrogen treatments (0, 100, 200 and 300 kg N ha -1) in varying application schemes to create differences in canopy nitrogen status during the growing season. Ten standard destructive field samplings were performed to follow leaf area index and crop dry weight evolution. Samples were analysed for inorganic nitrogen and total nitrogen contents. At sampling dates, spectral measurements were taken both at leaf level and at canopy level. At leaf level, an exponential relation between SPAD-502 readings and leaf organic nitrogen contents with a high correlation factor of 0.91 was found. At canopy level, an exponential relation between canopy organic nitrogen contents and red edge position ( λrep, nm) derived from reflectance measurements was found with a good correlation of 0.82. Spectral measurements (SPAD-502) at leaf level of a few square mm were related to canopy reflectance measurements (CropScan™) of approximately 0.44 m 2. Statistical regression techniques were used to optimise theoretical vertical nitrogen profiles that allowed scaling-up leaf chlorophyll measurements

  18. Fluxes of oxidised and reduced nitrogen above a mixed coniferous forest exposed to various nitrogen emission sources

    Energy Technology Data Exchange (ETDEWEB)

    Neirynck, J. [Research Institute for Nature and Forest, Gaverstraat 4, B-9500 Geraardsbergen (Belgium)]. E-mail: johan.neirynck@inbo.be; Kowalski, A.S. [Departamento de Fisica Aplicida, Facultad de Ciencias, Universidad de Granada, Calle Fuentenueva, SP-18071 Granada (Spain); Carrara, A. [Fundacion CEAM, Parque Technologico, Calle Charles H. Darwin 14, SP-46980 Paterna (Valencia) (Spain); Genouw, G. [Research Institute for Nature and Forest, Gaverstraat 4, B-9500 Geraardsbergen (Belgium); Berghmans, P. [Flemish Institute for Technological Research, Boeretang 200, B-2400 Mol (Belgium); Ceulemans, R. [Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk (Antwerp) (Belgium)

    2007-09-15

    Concentrations of nitrogen gases (NH{sub 3}, NO{sub 2}, NO, HONO and HNO{sub 3}) and particles (pNH{sub 4} and pNO{sub 3}) were measured over a mixed coniferous forest impacted by high nitrogen loads. Nitrogen dioxide (NO{sub 2}) represented the main nitrogen form, followed by nitric oxide (NO) and ammonia (NH{sub 3}). A combination of gradient method (NH{sub 3} and NO {sub x} ) and resistance modelling techniques (HNO{sub 3}, HONO, pNH{sub 4} and pNO{sub 3}) was used to calculate dry deposition of nitrogen compounds. Net flux of NH{sub 3} amounted to -64 ng N m{sup -2} s{sup -1} over the measuring period. Net fluxes of NO {sub x} were upward (8.5 ng N m{sup -2} s{sup -1}) with highest emission in the morning. Fluxes of other gases or aerosols substantially contributed to dry deposition. Total nitrogen deposition was estimated at -48 kg N ha{sup -1} yr{sup -1} and consisted for almost 80% of NH {sub x} . Comparison of throughfall nitrogen with total deposition suggested substantial uptake of reduced N ({+-}15 kg N ha{sup -1} yr{sup -1}) within the canopy. - Reduced nitrogen was found to be the main contributor to total deposition which was predominantly governed by dry deposition.

  19. Fluxes of oxidised and reduced nitrogen above a mixed coniferous forest exposed to various nitrogen emission sources

    International Nuclear Information System (INIS)

    Neirynck, J.; Kowalski, A.S.; Carrara, A.; Genouw, G.; Berghmans, P.; Ceulemans, R.

    2007-01-01

    Concentrations of nitrogen gases (NH 3 , NO 2 , NO, HONO and HNO 3 ) and particles (pNH 4 and pNO 3 ) were measured over a mixed coniferous forest impacted by high nitrogen loads. Nitrogen dioxide (NO 2 ) represented the main nitrogen form, followed by nitric oxide (NO) and ammonia (NH 3 ). A combination of gradient method (NH 3 and NO x ) and resistance modelling techniques (HNO 3 , HONO, pNH 4 and pNO 3 ) was used to calculate dry deposition of nitrogen compounds. Net flux of NH 3 amounted to -64 ng N m -2 s -1 over the measuring period. Net fluxes of NO x were upward (8.5 ng N m -2 s -1 ) with highest emission in the morning. Fluxes of other gases or aerosols substantially contributed to dry deposition. Total nitrogen deposition was estimated at -48 kg N ha -1 yr -1 and consisted for almost 80% of NH x . Comparison of throughfall nitrogen with total deposition suggested substantial uptake of reduced N (±15 kg N ha -1 yr -1 ) within the canopy. - Reduced nitrogen was found to be the main contributor to total deposition which was predominantly governed by dry deposition

  20. Modeling Nitrogen Decrease in Water Lettuce Ponds from Waste Stabilization Ponds

    Science.gov (United States)

    Putri, Gitta Agnes; Sunarsih

    2018-02-01

    This paper presents about the dynamic modeling of the Water Lettuce ponds as a form of improvement from the Water Hyacinth ponds. The purpose of this paper is to predict nitrogen decrease and nitrogen transformation in Water Lettuce ponds integrated with Waste Stabilization Ponds. The model consists of 4 mass balances, namely Dissolved Organic Nitrogen (DON), Particulate Organic Nitrogen (PON), ammonium (NH4+), Nitrate and Nitrite (NOx). The process of nitrogen transformation which considered in a Water Lettuce ponds, namely hydrolysis, mineralization, nitrification, denitrification, plant and bacterial uptake processes. Numerical simulations are performed by giving the values of parameters and the initial values of nitrogen compounds based on a review of previous studies. Numerical results show that the rate of change in the concentration of nitrogen compounds in the integration ponds of waste stabilization and water lettuce decreases and reaches stable at different times.

  1. Interactive Influence of N and P on their uptake by four different ...

    African Journals Online (AJOL)

    The uptake kinetics of nitrogen (N) and phosphorus (P) by hydrophytes can be influenced by the interaction between N and P. In this study, Pistia stratiotes (a floating plant), Eichhornia crassipes (a floating plant), Vallisneria spiralis (a submerged plant), and Cyperus papyrus (an emergent plant) were selected to measure ...

  2. Interactive Influence of N and P on their uptake by four different ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-10-06

    Oct 6, 2008 ... refreshment, the plants were left for 3 days in hydroponic culture without nitrogen ... The pH of the uptake solution was adjusted to 5.6 using 0.1 mmol/l HCl. ..... ascorbate specific peroxidase in spinach chloroplasts. Plant Cell.

  3. Sphagnum mosses : Masters of efficient N-uptake while avoiding intoxication

    NARCIS (Netherlands)

    Fritz, Christian; Lamers, Leon P.M.; Riaz, Muhammed; van den Berg, Leon J.L.; Elzenga, Theo J.T.M.

    2014-01-01

    Peat forming Sphagnum mosses are able to prevent the dominance of vascular plants under ombrotrophic conditions by efficiently scavenging atmospherically deposited nitrogen (N). N-uptake kinetics of these mosses are therefore expected to play a key role in differential N availability, plant

  4. Nitrogen utilization during spring phytoplankton bloom development in the southeast Bering Sea

    International Nuclear Information System (INIS)

    Sambrotto, R.N.

    1983-01-01

    Interactions beween a high latitude, continental shelf, spring phytoplankton bloom and water column physics and chemistry were studied using 15 N measured rates of nitrogen uptake. Peak bloom conditions commenced when the mixed layer shallowed and minimized respirational losses. Integrative light-mixing growth models were accurate during early bloom stages. An advection-diffusion model associated peak bloom nitrate uptake with pycnocline mixing rates of 2.1 m d -1 in an 18 m mixed layer. Maximum nitrogen specific uptake rates (hr -1 ), unlike those of carbon, coincided with peak bloom conditions. Although species compositions among peak bloom periods were similar, particulate C/N ratios were not. Apparently, both intercellular factors and prevailing mixing conditions influence specific uptake rates and cell composition. A large proportion of new (nitrate) to total productivity was associated with the dominance of the early bloom forming diatoms in the mixed layer. In the absence of these net plankton the residual nanoplankton dominated community exhibited a greater dependence on regenerated nitrogen. Nitrate uptake averaged 700 mg-at m -2 during the spring bloom and 1 g-at m -2 year -1 . The yearly f factor was 0.40. Nitrogen uptake based carbon productivity was 188 g C m -2 year -1

  5. Nitrogen trading tool

    Science.gov (United States)

    The nitrogen cycle is impacted by human activities, including those that increase the use of nitrogen in agricultural systems, and this impact can be seen in effects such as increased nitrate (NO3) levels in groundwater or surface water resources, increased concentration of nitrous oxide (N2O) in th...

  6. Nitrogen use efficiency (NUE)

    NARCIS (Netherlands)

    Oenema, O.

    2015-01-01

    There is a need for communications about resource use efficiency and for measures to increase the use efficiency of nutrients in relation to food production. This holds especially for nitrogen. Nitrogen (N) is essential for life and a main nutrient element. It is needed in relatively large

  7. Microbial Biofertilizer Decreases Nicotine Content by Improving Soil Nitrogen Supply.

    Science.gov (United States)

    Shang, Cui; Chen, Anwei; Chen, Guiqiu; Li, Huanke; Guan, Song; He, Jianmin

    2017-01-01

    Biofertilizers have been widely used in many countries for their benefit to soil biological and physicochemical properties. A new microbial biofertilizer containing Phanerochaete chrysosporium and Bacillus thuringiensis was prepared to decrease nicotine content in tobacco leaves by regulating soil nitrogen supply. Soil NO 3 - -N, NH 4 + -N, nitrogen supply-related enzyme activities, and nitrogen accumulation in plant leaves throughout the growing period were investigated to explore the mechanism of nicotine reduction. The experimental results indicated that biofertilizer can reduce the nicotine content in tobacco leaves, with a maximum decrement of 16-18 % in mature upper leaves. In the meantime, the total nitrogen in mature lower and middle leaves increased with the application of biofertilizer, while an opposite result was observed in upper leaves. Protein concentration in leaves had similar fluctuation to that of total nitrogen in response to biofertilizer. NO 3 - -N content and nitrate reductase activity in biofertilizer-amended soil increased by 92.3 and 42.2 %, respectively, compared to those in the control, whereas the NH 4 + -N and urease activity decreased by 37.8 and 29.3 %, respectively. Nitrogen uptake was improved in the early growing stage, but this phenomenon was not observed during the late growth period. Nicotine decrease is attributing to the adjustment of biofertilizer in soil nitrogen supply and its uptake in tobacco, which result in changes of nitrogen content as well as its distribution in tobacco leaves. The application of biofertilizer containing P. chrysosporium and B. thuringiensis can reduce the nicotine content and improve tobacco quality, which may provide some useful information for tobacco cultivation.

  8. Nitrogen in Chinese coals

    Science.gov (United States)

    Wu, D.; Lei, J.; Zheng, B.; Tang, X.; Wang, M.; Hu, Jiawen; Li, S.; Wang, B.; Finkelman, R.B.

    2011-01-01

    Three hundred and six coal samples were taken from main coal mines of twenty-six provinces, autonomous regions, and municipalities in China, according to the resource distribution and coal-forming periods as well as the coal ranks and coal yields. Nitrogen was determined by using the Kjeldahl method at U. S. Geological Survey (USGS), which exhibit a normal frequency distribution. The nitrogen contents of over 90% Chinese coal vary from 0.52% to 1.41% and the average nitrogen content is recommended to be 0.98%. Nitrogen in coal exists primarily in organic form. There is a slight positive relationship between nitrogen content and coal ranking. ?? 2011 Science Press, Institute of Geochemistry, CAS and Springer Berlin Heidelberg.

  9. Enhancing biological nitrogen fixation

    Energy Technology Data Exchange (ETDEWEB)

    Danso, S.K.A.; Eskew, D.L. (Joint FAO/IAEA Div. of Isotope and Radiation Applications of Atomic Energy for Food and Agricultural Development, Vienna (Austria))

    1984-06-01

    Several co-ordinated research programmes (CRPs) conducted by the Soil Fertility, Irrigation and Crop Production Section of the Joint FAO/IAEA Division have concentrated on finding the most efficient way of applying nitrogen fertilizers to various crops, using nitrogen-15 (/sup 15/N) as a tracer. The findings of these studies have been adopted in many countries around the world, resulting in savings of nitrogen fertilizers worth many millions of dollars every year. More recently, the Section's CRPs have focused on enhancing the natural process of biological di-nitrogen fixation. The /sup 15/N isotope technique has proven to be very valuable in studies of the legume-Rhizobium symbiosis, allowing many more experiments than before to be done and yielding much new practical information. The Soils Section is now working to extend the use of the technique to other nitrogen-fixing symbioses.

  10. Technetium uptake by Sinapis Alba

    International Nuclear Information System (INIS)

    Mueller, H.; Ter Meer-Bekk, Ch.

    1986-01-01

    Transfer factors for pertechnetate uptake was determined for Sinapis Alba cultured hydroponically. For the freshly harvested, undried plants transfer factors were found between 13 and 40 depending on the growth period. (author)

  11. [Nitrogen input altered testate amoebae community in peatland of Sanjiang Plain, Northeast China].

    Science.gov (United States)

    Song, Li-hong; Yan, Xiu-min; Wang, Ke-hong; Zhu, Xiao-yan; Wu, Dong-hu

    2015-02-01

    In the present study, an in situ control experiment was carried out to explore the response of testate amoebae to exogenous nitrogen addition in peatland of Sanjiang Plain. The results showed that nitrogen addition increased the biomass of testate amoebae at lower levels (6 g N · m(-2)), while decreased it at higher levels (> 12 g N · m(-2)). At genus level, nitrogen addition significantly increased the biomass of Arcella and Phryganella, decreased the biomass of Euglypha. Only lower nitrogen addition significantly increased the biomass of Centropyxis. At species level, nitrogen addition significantly decreased the biomass of Euglypha rotunda, while the biomass of either Centropyxis cassis or Phryganella acropodia was increased by a lower nitrogen addition treatment. This study suggested that the response of peatland testate amoebae to nitrogen addition was species specific, which could potentially be used as an indicator for the environment of peatlands.

  12. On the virtue of acid–base titrations for the determination of basic sites in nitrogen doped carbon nanotubes

    NARCIS (Netherlands)

    Bitter, J.H.; van Dommele, S.; de Jong, K.P.

    2013-01-01

    The basicity and nature of basic species in nitrogen containing carbon nanotubes (NCNT) prepared under different conditions were investigated by acid–base titrations. Proton uptake curves were derived from the titration data and were used to establish the basicity (pKa) ranges of nitrogen species

  13. Demonstrating Paramagnetism Using Liquid Nitrogen.

    Science.gov (United States)

    Simmonds, Ray; And Others

    1994-01-01

    Describes how liquid nitrogen is attracted to the poles of neodymium magnets. Nitrogen is not paramagnetic, so the attraction suggests that the liquid nitrogen contains a small amount of oxygen, which causes the paramagnetism. (MVL)

  14. Diselenolane-mediated cellular uptake.

    Science.gov (United States)

    Chuard, Nicolas; Poblador-Bahamonde, Amalia I; Zong, Lili; Bartolami, Eline; Hildebrandt, Jana; Weigand, Wolfgang; Sakai, Naomi; Matile, Stefan

    2018-02-21

    The emerging power of thiol-mediated uptake with strained disulfides called for a move from sulfur to selenium. We report that according to results with fluorescent model substrates, cellular uptake with 1,2-diselenolanes exceeds uptake with 1,2-dithiolanes and epidithiodiketopiperazines with regard to efficiency as well as intracellular localization. The diselenide analog of lipoic acid performs best. This 1,2-diselenolane delivers fluorophores efficiently to the cytosol of HeLa Kyoto cells, without detectable endosomal capture as with 1,2-dithiolanes or dominant escape into the nucleus as with epidithiodiketopiperazines. Diselenolane-mediated cytosolic delivery is non-toxic (MTT assay), sensitive to temperature but insensitive to inhibitors of endocytosis (chlorpromazine, methyl-β-cyclodextrin, wortmannin, cytochalasin B) and conventional thiol-mediated uptake (Ellman's reagent), and to serum. Selenophilicity, the extreme CSeSeC dihedral angle of 0° and the high but different acidity of primary and secondary selenols might all contribute to uptake. Thiol-exchange affinity chromatography is introduced as operational mimic of thiol-mediated uptake that provides, in combination with rate enhancement of DTT oxidation, direct experimental evidence for existence and nature of the involved selenosulfides.

  15. CO{sub 2} removal potential of carbons prepared by co-pyrolysis of sugar and nitrogen containing compounds

    Energy Technology Data Exchange (ETDEWEB)

    Arenillas, A.; Drage, T.C.; Smith, K.; Snape, C.E. [University of Nottingham, Fuel Science Group, School of Chemical, Environmental and Mining Engineering, University Park, Nottingham NG7 2RD (United Kingdom)

    2005-08-15

    The nitrogen enrichment of active carbons is reported to be effective in enhancing the specific adsorbate-adsorbent interactions for CO{sub 2}. In this work, nitrogen-enriched carbons were prepared by co-pyrolysis of sugar and a series of nitrogen compounds with different nitrogen functionalities. The results show that although the amount of nitrogen incorporated to the final adsorbent is important, the N-functionality seems to be more relevant for increasing CO{sub 2} uptake. Thus, the adsorbent obtained from urea co-pyrolysis presents the highest nitrogen content but the lowest CO{sub 2} adsorption capacity. However, the adsorbent obtained from carbazole co-pyrolysis, despite the lower amount of N incorporated, shows high CO{sub 2} uptake, up to 9wt.%, probably because the presence of more basic functionalities as determined by XPS analysis.

  16. Distillation of shale in situ

    Energy Technology Data Exchange (ETDEWEB)

    de Ganahl, C F

    1922-07-04

    To distill buried shale or other carbon containing compounds in situ, a portion of the shale bed is rendered permeable to gases, and the temperature is raised to the point of distillation. An area in a shale bed is shattered by explosives, so that it is in a relatively finely divided form, and the tunnel is then blocked by a wall, and fuel and air are admitted through pipes until the temperature of the shale is raised to such a point that a portion of the released hydrocarbons will burn. When distillation of the shattered area takes place and the lighter products pass upwardly through uptakes to condensers and scrubbers, liquid oil passes to a tank and gas to a gasometer while heavy unvaporized products in the distillation zone collect in a drain, flow into a sump, and are drawn off through a pipe to a storage tank. In two modifications, methods of working are set out in cases where the shale lies beneath a substantially level surface.

  17. Nutrient Uptake and Metabolism Along a Large Scale Tropical Physical-Chemical Gradient

    Science.gov (United States)

    Tromboni, F.; Neres-Lima, V.; Saltarelli, W. A.; Miwa, A. C. P.; Cunha, D. G. F.

    2016-12-01

    Nutrient spiraling is a whole-system approach for estimating nutrient uptake that can be used to assess aquatic ecosystems' responses to environmental change and anthropogenic impacts. Historically research on nutrient dynamic uptake in streams has focused on single nutrient dynamics and only rarely the stoichiometric uptake has been considered and linked to carbon metabolism driven by autotrophic and heterotrophic production. We investigated the relationship between uptake of phosphate (PO43-), nitrate (NO3-) ammonium (NH4+) and total dissolve nitrogen (DIN)/ PO43-; and gross primary production (GPP), respiration (R), and net ecosystem productivity (NEP) in six relatively pristine streams with differences regarding canopy cover and physical characteristics, located in a large scale gradient from tropical Atlantic Forest to an Atlantic forest/Cerrado (Brazilian Savanna) transition. We carried out whole stream instantaneous additions of PO43-, NO3- and NH4+ added to each stream in combination, using the TASCC (Tracer Additions for Spiraling Curve Characterization) method. Metabolism measurements were performed in the same streams right after uptake was measured, using one-station open channel method and re-aeration estimations for those sites. We found different background concentrations in the streams located in the Atlantic forest compared with the transition area with Cerrado. In general PO43- and NO3- uptake increased with the decreasing of canopy cover, while a positive relation with background concentration better explained NH4+uptake. DIN/PO43- uptake increased with increasing R and NEP. Little work on functional characteristics of pristine streams has been conducted in this region and this work provides an initial characterization on nitrogen and phosphorus dynamics as well as their stoichiometric uptake in streams.

  18. The nitrogen cycle.

    Science.gov (United States)

    Stein, Lisa Y; Klotz, Martin G

    2016-02-08

    Nitrogen is the fourth most abundant element in cellular biomass, and it comprises the majority of Earth's atmosphere. The interchange between inert dinitrogen gas (N2) in the extant atmosphere and 'reactive nitrogen' (those nitrogen compounds that support, or are products of, cellular metabolism and growth) is entirely controlled by microbial activities. This was not the case, however, in the primordial atmosphere, when abiotic reactions likely played a significant role in the inter-transformation of nitrogen oxides. Although such abiotic reactions are still important, the extant nitrogen cycle is driven by reductive fixation of dinitrogen and an enzyme inventory that facilitates dinitrogen-producing reactions. Prior to the advent of the Haber-Bosch process (the industrial fixation of N2 into ammonia, NH3) in 1909, nearly all of the reactive nitrogen in the biosphere was generated and recycled by microorganisms. Although the Haber-Bosch process more than quadrupled the productivity of agricultural crops, chemical fertilizers and other anthropogenic sources of fixed nitrogen now far exceed natural contributions, leading to unprecedented environmental degradation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Endocytosis of the major yolk proteins of the silkmoth, Hyalophora cecropia: Uptake kinetics and interactions

    International Nuclear Information System (INIS)

    Kulakosky, P.C.

    1989-01-01

    The oocytes of Lepidopteran insects take up several yolk proteins in defined proportions even though their relative availability in the hemolymph changes during the several days required to complete yolk formation in all the eggs. There are three hemolymph yolk precursors, vitellogenin, microvitellogenin and lipophorin; one precursor, paravitellogenin is produced in the ovary. The control mechanism for their proportional endocytosis is not known. In this thesis, the author describe the purification of all four proteins and the radiolabeling of the hemolymph precursors. The radiolabeled proteins were tested with an in vitro incubation system to assess the biological activity of the proteins and the reliability of the incubation methods. All of the labeled probes were transferred from the incubation medium to yolk spheres within the oocyte in a saturable, energy-dependent, and stage-specific manner. The rates of uptake were similar to the estimated rates of uptake in situ. The concentration dependence of in vitro uptake was investigated and found to be consistent with in situ concentrations and the composition of yolk in mature eggs. Two precursors, vitellogenin and lipophorin, competed for uptake indicating that they share a common binding site while the third, microvitellin, did not compete with the others. Though vitellogenin and lipophorin competed for uptake, only vitellogenin displayed the unique ability to increase the uptake rate of microvitellin and fluid in vitro

  20. Terrestrial nitrogen-carbon cycle interactions at the global scale.

    Science.gov (United States)

    Zaehle, S

    2013-07-05

    Interactions between the terrestrial nitrogen (N) and carbon (C) cycles shape the response of ecosystems to global change. However, the global distribution of nitrogen availability and its importance in global biogeochemistry and biogeochemical interactions with the climate system remain uncertain. Based on projections of a terrestrial biosphere model scaling ecological understanding of nitrogen-carbon cycle interactions to global scales, anthropogenic nitrogen additions since 1860 are estimated to have enriched the terrestrial biosphere by 1.3 Pg N, supporting the sequestration of 11.2 Pg C. Over the same time period, CO2 fertilization has increased terrestrial carbon storage by 134.0 Pg C, increasing the terrestrial nitrogen stock by 1.2 Pg N. In 2001-2010, terrestrial ecosystems sequestered an estimated total of 27 Tg N yr(-1) (1.9 Pg C yr(-1)), of which 10 Tg N yr(-1) (0.2 Pg C yr(-1)) are due to anthropogenic nitrogen deposition. Nitrogen availability already limits terrestrial carbon sequestration in the boreal and temperate zone, and will constrain future carbon sequestration in response to CO2 fertilization (regionally by up to 70% compared with an estimate without considering nitrogen-carbon interactions). This reduced terrestrial carbon uptake will probably dominate the role of the terrestrial nitrogen cycle in the climate system, as it accelerates the accumulation of anthropogenic CO2 in the atmosphere. However, increases of N2O emissions owing to anthropogenic nitrogen and climate change (at a rate of approx. 0.5 Tg N yr(-1) per 1°C degree climate warming) will add an important long-term climate forcing.

  1. Root Ideotype Influences Nitrogen Transport and Assimilation in Maize

    Directory of Open Access Journals (Sweden)

    Julie Dechorgnat

    2018-04-01

    Full Text Available Maize (Zea mays, L. yield is strongly influenced by external nitrogen inputs and their availability in the soil solution. Overuse of nitrogen-fertilizers can have detrimental ecological consequences through increased nitrogen pollution of water and the release of the potent greenhouse gas, nitrous oxide. To improve yield and overall nitrogen use efficiency (NUE, a deeper understanding of nitrogen uptake and utilization is required. This study examines the performance of two contrasting maize inbred lines, B73 and F44. F44 was selected in Florida on predominantly sandy acidic soils subject to nitrate leaching while B73 was selected in Iowa on rich mollisol soils. Transcriptional, enzymatic and nitrogen transport analytical tools were used to identify differences in their N absorption and utilization capabilities. Our results show that B73 and F44 differ significantly in their genetic, enzymatic, and biochemical root nitrogen transport and assimilatory pathways. The phenotypes show a strong genetic relationship linked to nitrogen form, where B73 showed a greater capacity for ammonium transport and assimilation whereas F44 preferred nitrate. The contrasting phenotypes are typified by differences in root system architecture (RSA developed in the presence of both nitrate and ammonium. F44 crown roots were longer, had a higher surface area and volume with a greater lateral root number and density than B73. In contrast, B73 roots (primary, seminal, and crown were more abundant but lacked the defining features of the F44 crown roots. An F1 hybrid between B73 and F44 mirrored the B73 nitrogen specificity and root architecture phenotypes, indicating complete dominance of the B73 inbred. This study highlights the important link between RSA and nitrogen management and why both variables need to be tested together when defining NUE improvements in any selection program.

  2. Effect of Nitrogen Foliar Application on Canola Yield (Brassica napus L. and Nitrogen Efficiency across Different Sowing Dates

    Directory of Open Access Journals (Sweden)

    S Doori

    2016-12-01

    Full Text Available Introduction Between oil seeds, from the quality, quantity and nutrition index point of view, canola has the top level . Because of the solubility of N fertilizers, the time of urea application, is very important and one of the main reasons of the reduction in N application efficiency is utilization of urea in an inappropriate time. By precisely foliar application of nitrogen, the efficiency of nitrogen transformation to the grain will be very high because in this method the leaf is considered the main organ of nitrogen uptake and a low amount of absorbed nitrogen was transferred to the root and entered the soil. The more division of N application in growth stages and in accordance with plant need and foliar application result in increasing nitrogen use efficiency. The delay in sowing will result in the reduction of yield and this is due to low LAI, and thus low radiation absorb in vegetable phase and shorter reproductive phase with high temperature in flowering and subsequent stages that result in low prolific silique and make disorder in transferring stored material to grain. In this experiment using N foliar application to decrease the adverse effect of delay in sowing is objective. Materials and Methods The experiment was conducted in 2013-2014 in Ramin Agriculture and Natural Resource University of Khuzestan. Experiment was conducted as split plots in a randomized complete blocks design with three replications. In this experiment sowing date]optimum sowing (27 November, 17 December and late sowing (30 December [were assigned to main plots and several time of N-foliar application with 5 percent density from urea (20 liter per ha, ]TO (control, T1 (foliar N application in rosette stage, T2 (foliar N application in budding stage, T3 (foliar N application in flowering stage[ were placed in sub-plots in randomized way. Fertilizing was based on the results of soil examination. Therefore, 162 kg ha-1 of pure nitrogen (from resource urea in the way

  3. Importance of soil nitrogen and select intensifying measures in the soil-plant-fertilizer system demonstrated in sugar beets

    International Nuclear Information System (INIS)

    Rauhe, K.; Sielaff, B.; Barth, F.J.

    1981-01-01

    Sugar beets were gradually fertilized with 15 N-labelled nitrogen fertilizer without or in combination with irrigation. To gain optimum crop yields 180 - 200 kg/ha fertilizer nitrogen were required. Within the range of maximum yield the total nitrogen uptake amounted to 300 - 360 kg/ha under conditions of irrigation. Nitrogen was taken up from the fertilizer by 40% and from the soil by 60%. The immobilization rate of fertilizer nitrogen was near 30% after 2 years of vegetation. Only 33% and 25%, resp., of soil nitrogen could be replaced by fertilizing without and combined with irrigation, resp. It was shown that despite of increased application of the main intensifying factors, nitrogen and water, the soil nitrogen was mineralized intensively

  4. Root uptake of transuranic elements

    International Nuclear Information System (INIS)

    Schulz, R.K.

    1977-01-01

    The uptake of elements by plant roots is one of the important pathways of entry of many elements into the food chain of man. Data are cited showing plutonium concentration ratios, plant/soil, ranging from 10 -10 to 10 -3 . Concentration ratios for americium range from 10 -7 to 10 +1 . Limited experiments with curium and neptunium indicate that root uptake of curium is similar to that of americium and that plant uptake of neptunium is substantially larger than that of curium and americium. The extreme ranges of concentration ratios cited for plutonium and americium are due to a number of causes. Experimental conditions such as very intensive cropping will lead to abnormally high concentration ratios. In some experiments, addition of chelating agents markedly increased plant root uptake of transuranic elements. Particle size and composition of the source material influenced uptake of the transuranics by plants. Translocation within the plant, and soil factors such as pH and organic matter content, all affect concentration ratios

  5. Competition for nitrogen between Fagus sylvatica and Acer pseudoplatanus seedlings depends on soil nitrogen availability

    Directory of Open Access Journals (Sweden)

    Xiuyuan eLi

    2015-04-01

    Full Text Available Competition for nitrogen (N, particularly in resource-limited habitats, might be avoided by different N acquisition strategies of plants. In our study, we investigated whether slow-growing European beech and fast-growing sycamore maple seedlings avoid competition for growth-limiting N by different N uptake patterns and the potential alteration by soil N availability in a microcosm experiment. We quantified growth and biomass indices, 15N uptake capacity and N pools in the fine roots. Overall, growth indices, N acquisition and N pools in the fine roots were influenced by species-specific competition depending on soil N availability. With interspecific competition, growth of sycamore maple reduced regardless of soil N supply, whereas beech only showed reduced growth when N was limited. Both species responded to interspecific competition by alteration of N pools in the fine roots; however, sycamore maple showed a stronger response compared to beech for almost all N pools in roots, except for structural N at low soil N availability. Beech generally preferred organic N acquisition while sycamore maple took up more inorganic N. Furthermore, with interspecific competition, beech had an enhanced organic N uptake capacity, while in sycamore maple inorganic N uptake capacity was impaired by the presence of beech. Although sycamore maple could tolerate the suboptimal conditions at the cost of reduced growth, our study indicates its reduced competitive ability for N compared to beech.

  6. Mineral commodity profiles: nitrogen

    Science.gov (United States)

    Kramer, Deborah A.

    2004-01-01

    Overview -- Nitrogen (N) is an essential element of life and a part of all animal and plant proteins. As a part of the DNA and RNA molecules, nitrogen is an essential constituent of each individual's genetic blueprint. As an essential element in the chlorophyll molecule, nitrogen is vital to a plant's ability to photosynthesize. Some crop plants, such as alfalfa, peas, peanuts, and soybeans, can convert atmospheric nitrogen into a usable form by a process referred to as 'fixation.' Most of the nitrogen that is available for crop production, however, comes from decomposing animal and plant waste or from commercially produced fertilizers. Commercial fertilizers contain nitrogen in the form of ammonium and/or nitrate or in a form that is quickly converted to the ammonium or nitrate form once the fertilizer is applied to the soil. Ammonia is generally the source of nitrogen in fertilizers. Anhydrous ammonia is commercially produced by reacting nitrogen with hydrogen under high temperatures and pressures. The source of nitrogen is the atmosphere, which is almost 80 percent nitrogen. Hydrogen is derived from a variety of raw materials, which include water, and crude oil, coal, and natural gas hydrocarbons. Nitrogen-based fertilizers are produced from ammonia feedstocks through a variety of chemical processes. Small quantities of nitrates are produced from mineral resources principally in Chile. In 2002, anhydrous ammonia and other nitrogen materials were produced in more than 70 countries. Global ammonia production was 108 million metric tons (Mt) of contained nitrogen. With 28 percent of this total, China was the largest producer of ammonia. Asia contributed 46 percent of total world ammonia production, and countries of the former U.S.S.R. represented 13 percent. North America also produced 13 percent of the total; Western Europe, 9 percent; the Middle East, 7 percent; Central America and South America, 5 percent; Eastern Europe, 3 percent; and Africa and Oceania

  7. Commercial Nitrogen Fertilizer Purchased

    Data.gov (United States)

    U.S. Environmental Protection Agency — Amounts of fertilizer nitrogen (N) purchased by states in individual years 2003, 2005, 2007, 2009 and 2011, and the % change in average amounts purchased per year...

  8. Niche differentiation in nitrogen metabolism among methanotrophs within an operational taxonomic unit.

    Science.gov (United States)

    Hoefman, Sven; van der Ha, David; Boon, Nico; Vandamme, Peter; De Vos, Paul; Heylen, Kim

    2014-04-04

    The currently accepted thesis on nitrogenous fertilizer additions on methane oxidation activity assumes niche partitioning among methanotrophic species, with activity responses to changes in nitrogen content being dependent on the in situ methanotrophic community structure Unfortunately, widely applied tools for microbial community assessment only have a limited phylogenetic resolution mostly restricted to genus level diversity, and not to species level as often mistakenly assumed. As a consequence, intragenus or intraspecies metabolic versatility in nitrogen metabolism was never evaluated nor considered among methanotrophic bacteria as a source of differential responses of methane oxidation to nitrogen amendments. We demonstrated that fourteen genotypically different Methylomonas strains, thus distinct below the level at which most techniques assign operational taxonomic units (OTU), show a versatile physiology in their nitrogen metabolism. Differential responses, even among strains with identical 16S rRNA or pmoA gene sequences, were observed for production of nitrite and nitrous oxide from nitrate or ammonium, nitrogen fixation and tolerance to high levels of ammonium, nitrate, and hydroxylamine. Overall, reduction of nitrate to nitrite, nitrogen fixation, higher tolerance to ammonium than nitrate and tolerance and assimilation of nitrite were general features. Differential responses among closely related methanotrophic strains to overcome inhibition and toxicity from high nitrogen loads and assimilation of various nitrogen sources yield competitive fitness advantages to individual methane-oxidizing bacteria. Our observations proved that community structure at the deepest phylogenetic resolution potentially influences in situ functioning.

  9. Understanding plant response to nitrogen limitation for the improvement of crop nitrogen use efficiency.

    Science.gov (United States)

    Kant, Surya; Bi, Yong-Mei; Rothstein, Steven J

    2011-02-01

    Development of genetic varieties with improved nitrogen use efficiency (NUE) is essential for sustainable agriculture. Generally, NUE can be divided into two parts. First, assimilation efficiency involves nitrogen (N) uptake and assimilation and second utilization efficiency involves N remobilization. Understanding the mechanisms regulating these processes is crucial for the improvement of NUE in crop plants. One important approach is to develop an understanding of the plant response to different N regimes, especially to N limitation, using various methods including transcription profiling, analysing mutants defective in their normal response to N limitation, and studying plants that show better growth under N-limiting conditions. One can then attempt to improve NUE in crop plants using the knowledge gained from these studies. There are several potential genetic and molecular approaches for the improvement of crop NUE discussed in this review. Increased knowledge of how plants respond to different N levels as well as to other environmental conditions is required to achieve this.

  10. A new method for tracing flows of nitrogen and carbon through bacteria and algae in aquatic microbial communities: Analysis of 15N- and 13C-incorporation into D-alanine and other hydrolysable amino acids

    NARCIS (Netherlands)

    Veuger, B.

    2006-01-01

    Nitrogen flows through bacteria and algae in aquatic microbial communities are an important part of the nitrogen cycle, which plays a central role in aquatic ecosystems. However, work on uptake and retention of nitrogen in bacteria versus algae in natural microbial communities has long been hampered

  11. Variability of insulin-stimulated myocardial glucose uptake in healthy elderly subjects

    DEFF Research Database (Denmark)

    Kofoed, Klaus F; Hove, Jens D; Freiberg, Jacob

    2002-01-01

    The aim of this study was to assess regional and global variability of insulin-stimulated myocardial glucose uptake in healthy elderly subjects and to evaluate potentially responsible factors. Twenty men with a mean age of 64 years, no history of cardiovascular disease, and normal blood pressure...... rest and hyperaemic blood flow during dipyridamole infusion were measured with nitrogen-13 ammonia and positron emission tomography in 16 left ventricular myocardial segments. Intra-individual and inter-individual variability of insulin-stimulated myocardial glucose uptake [relative dispersion...... = (standard deviation/mean)] was 13% and 29% respectively. Although inter-individual variability of glucose uptake and blood flow at rest was of the same magnitude, no correlation was found between these measures. Regional and global insulin-stimulated myocardial glucose uptake correlated linearly with whole...

  12. Effects of Mg on C and N Metabolism of Soybean at Different Nitrogen Supplying Levels

    Institute of Scientific and Technical Information of China (English)

    LANG Man; LIU Yuanying; PENG Xianlong; ZHANG Wenzhao

    2006-01-01

    A pot experiment was conducted to study the effects of magnesium on carbon and nitrogen metabolism of soybean at different nitrogen supplying levels. The results showed that the effects of magnesium at low nitrogen rate on N content, soluble protein, soluble sugar contents were not alike at different growth stage, although nodule dry weights raised, the yield and protein content of seeds decreased, however, the oil content was improved.The application of magnesium at medium and high nitrogen supplying levels promoted the uptake of N effectively,increased the soluble protein and soluble sugar contents, but the nodule dry weights of application magnesium at medium nitrogen supplying level decreased and the yield increased only a little despite the improved quality.Application of magnesium at high nitrogen supplying level raised nodule dry weights and soybean yield significantly, the quality of seeds was also improved.

  13. IMPROVING NITROGEN FERTILIZER ABSORPTION AND ITS EFFECT ON QUALITY AND SEED YIELD OF CORN (Zea mays

    Directory of Open Access Journals (Sweden)

    Kuswanto

    2013-06-01

    Full Text Available Improving nitrogen uptake by pyraclostrobin application in maize under green house and field conditions were investigated. There were three series experiments conducted in dry season, 2011 and 2012. The research conducted using nested design and three replications. Nested design applied to get information as careful as possible about the role of treatment, especially the main factor. The first and second experiments hold at field and green house and the third experiment hold at green house. They had two factors, pyraclostrobin application and nitrogen fertilizer. Vegetative growth, flowering and earing age, chlorophyll content, yield, amylose and protein content evaluated. Application of pyraclostrobin, significantly increase nitrogen fertilizer efficiency. Amylose content and fresh yield were different on nitrogen and pyraclostrobin application. Application of pyraclostrobin 400 ml/ha significantly increase amylose 10.85-18.5%. Both of amylose and protein content were increased by nitrogen fertilizer application. Vegetative growth and chlorophyll content were affected by nitrogen and pyraclostrobin.

  14. The importance of cytosolic glutamine synthetase in nitrogen assimilation and recycling

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, S.M.; Habash, D.Z.

    2009-07-02

    Glutamine synthetase assimilates ammonium into amino acids, thus it is a key enzyme for nitrogen metabolism. The cytosolic isoenzymes of glutamine synthetase assimilate ammonium derived from primary nitrogen uptake and from various internal nitrogen recycling pathways. In this way, cytosolic glutamine synthetase is crucial for the remobilization of protein-derived nitrogen. Cytosolic glutamine synthetase is encoded by a small family of genes that are well conserved across plant species. Members of the cytosolic glutamine synthetase gene family are regulated in response to plant nitrogen status, as well as to environmental cues, such as nitrogen availability and biotic/abiotic stresses. The complex regulation of cytosolic glutamine synthetase at the transcriptional to post-translational levels is key to the establishment of a specific physiological role for each isoenzyme. The diverse physiological roles of cytosolic glutamine synthetase isoenzymes are important in relation to current agricultural and ecological issues.

  15. Lactate, Glucose and Oxygen Uptake in Human Brain During Recovery from Maximal Exercise

    DEFF Research Database (Denmark)

    Kojiro, I.; Schmalbruch, I.K.; Quistorff, B.

    1999-01-01

    Skeletal muscle, brain lactate uptake, brain oxygen uptake, energy metabolism, brain glucose uptake......Skeletal muscle, brain lactate uptake, brain oxygen uptake, energy metabolism, brain glucose uptake...

  16. In-Situ Simulation

    DEFF Research Database (Denmark)

    Bjerregaard, Anders Thais; Slot, Susanne; Paltved, Charlotte

    2015-01-01

    , and organisational characteristic. Therefore, it might fail to fully mimic real clinical team processes. Though research on in situ simulation in healthcare is in its infancy, literature is abundant on patient safety and team training1. Patient safety reporting systems that identify risks to patients can improve......Introduction: In situ simulation offers on-site training to healthcare professionals. It refers to a training strategy where simulation technology is integrated into the clinical encounter. Training in the simulation laboratory does not easily tap into situational resources, e.g. individual, team...... patient safety if coupled with training and organisational support. This study explored the use of critical incidents and adverse events reports for in situ simulation and short-term observations were used to create learning objectives and training scenarios. Method: This study used an interventional case...

  17. In-Situ Air Sparaing: Engineering and Design

    Science.gov (United States)

    2008-01-31

    removal (Adams and Reddy 2000). The potential for remediation of less volatile LNAPLs (e.g., diesel or fuel oils) is less promising, relying more on...pure nitrogen, or nitrous oxide) may enhance the speed at which bioremediation proceeds or alter the conditions under which it occurs. The USDOE Sa...region below the water table is directly related to in- situ bioremediation . IAS can be an alternative to other means of introducing oxygen into the

  18. Effect of organic matter application and water regimes on the transformation of fertilizer nitrogen in a Philippine soil

    International Nuclear Information System (INIS)

    Yoshida, Tomio; Padre, B.C. Jr.

    1975-01-01

    Greenhouse experiments using the tracer technique showed that about 20 per cent of the fertilizer nitrogen added as basal to the Maahas clay soil was immobilized in submerged soils to which no organic material was added. The addition of organic matter to the soil increases the amount of nitrogen immobilized and the magnitude depends on the carbon to nitrogen ratio of the materials added. More fertilizer nitrogen was immobilized in the soils under upland and alternate wet-and-dry conditions than under submerged soil conditions. The uptake of fertilizer nitrogen by rice plants growing under submerged soil conditions ceased at the vegetative stage of growth because only a small amount of available nitrogen remains in the soil at this time, but the rice plant continued to absorb gradually untagged nitrogen from the soil throughout the reproductive stages of growth. Losses of fertilizer nitrogen were great under the alternate wet-and-dry conditions (submerged-upland). The loss of nitrogen from the soil-plant system was reduced by the addition of rice straw, which also reduced the uptake of fertilizer nitrogen but not the total dry matter production under the experimental conditions. Fertilizer nitrogen immobilized during the first crop remained mostly in the soil throughout the full period of the second crop. The total nitrogen uptake by rice plants was not affected by the soil moisture tension under the upland conditions used in the study but the movement of nitrogen from the leaves to the panicles during the reproductive stage seemed to decrease as the soil moisture tension increased. (auth.)

  19. Utilization of inorganic and organic nitrogen by bacteria in marine systems

    International Nuclear Information System (INIS)

    Wheeler, P.A.; Kirchman, D.L.

    1986-01-01

    The relative contribution of various inorganic and organic forms of nitrogen to the nitrogen requirements of picoplankton was examined with 15 N tracers. Size fractionation was used to measure uptake by <1-μm size microorganisms, and inhibitors of protein synthesis were used to separate procaryotic from eucaryotic nitrogen uptake. Picoplankton utilized mainly ammonium and amino acids and only negligible amounts of nitrate and urea. Nearly all amino acid uptake was by procaryotes, while both procaryotes and eucaryotes utilized ammonium. About 78% of total ammonium uptake was by procaryotes, and a significant portion of this was due specifically to heterotrophic bacteria. Regeneration of ammonium was correlated with eucaryotic rather than procaryotic activity. Ammonium accounted for at least 20-60% of the summed ammonium plus amino acid utilization by bacteria. The results suggest that significant portion of ammonium uptake in the euphotic zone was by heterotrophic bacteria rather than solely by phytoplankton. This may invalidate the use of the Redfield C:N ratio for estimating rates of nitrogen assimilation in the euphotic zone from carbon assimilation rates

  20. Modeling continuous cultures of microalgae colimited by nitrogen and phosphorus.

    Science.gov (United States)

    Bougaran, Gaël; Bernard, Olivier; Sciandra, Antoine

    2010-08-07

    It is well documented that the combination of low nitrogen and phosphorus resources can lead to situations where colimitation of phytoplankton growth arises, yet the underlying mechanisms are not fully understood. Here, we propose a Droop-based model built on the idea that colimitation by nitrogen and phosphorus arises from the uptake of nitrogen. Indeed, since N-porters are active systems, they require energy that could be related to the phosphorus status of the cell. Therefore, we assumed that N uptake is enhanced by the P quota. Our model also accounts for the biological observations that uptake of a nutrient can be down-regulated by its own internal quota, and succeeds in describing the strong contrast for the non-limiting quotas under N-limited and P-limited conditions that was observed on continuous cultures with Selenastrum minutum and with Isochrysis affinis galbana. Our analysis suggests that, regarding the colimitation concept, N and P would be better considered as biochemically dependent rather than biochemically independent nutrients. Copyright 2010 Elsevier Ltd. All rights reserved.

  1. Nitrate removal in stream ecosystems measured by 15N addition experiments: Total uptake

    Science.gov (United States)

    Hall, R.O.; Tank, J.L.; Sobota, D.J.; Mulholland, P.J.; O'Brien, J. M.; Dodds, W.K.; Webster, J.R.; Valett, H.M.; Poole, G.C.; Peterson, B.J.; Meyer, J.L.; McDowell, W.H.; Johnson, S.L.; Hamilton, S.K.; Grimm, N. B.; Gregory, S.V.; Dahm, Clifford N.; Cooper, L.W.; Ashkenas, L.R.; Thomas, S.M.; Sheibley, R.W.; Potter, J.D.; Niederlehner, B.R.; Johnson, L.T.; Helton, A.M.; Crenshaw, C.M.; Burgin, A.J.; Bernot, M.J.; Beaulieu, J.J.; Arangob, C.P.

    2009-01-01

    We measured uptake length of 15NO-3 in 72 streams in eight regions across the United States and Puerto Rico to develop quantitative predictive models on controls of NO-3 uptake length. As part of the Lotic Intersite Nitrogen eXperiment II project, we chose nine streams in each region corresponding to natural (reference), suburban-urban, and agricultural land uses. Study streams spanned a range of human land use to maximize variation in NO-3 concentration, geomorphology, and metabolism. We tested a causal model predicting controls on NO-3 uptake length using structural equation modeling. The model included concomitant measurements of ecosystem metabolism, hydraulic parameters, and nitrogen concentration. We compared this structural equation model to multiple regression models which included additional biotic, catchment, and riparian variables. The structural equation model explained 79% of the variation in log uptake length (S Wtot). Uptake length increased with specific discharge (Q/w) and increasing NO-3 concentrations, showing a loss in removal efficiency in streams with high NO-3 concentration. Uptake lengths shortened with increasing gross primary production, suggesting autotrophic assimilation dominated NO-3 removal. The fraction of catchment area as agriculture and suburban-urban land use weakly predicted NO-3 uptake in bivariate regression, and did improve prediction in a set of multiple regression models. Adding land use to the structural equation model showed that land use indirectly affected NO-3 uptake lengths via directly increasing both gross primary production and NO-3 concentration. Gross primary production shortened SWtot, while increasing NO-3 lengthened SWtot resulting in no net effect of land use on NO- 3 removal. ?? 2009.

  2. In situ groundwater bioremediation

    Energy Technology Data Exchange (ETDEWEB)

    Hazen, Terry C.

    2009-02-01

    In situ groundwater bioremediation of hydrocarbons has been used for more than 40 years. Most strategies involve biostimulation; however, recently bioaugmentation have been used for dehalorespiration. Aquifer and contaminant profiles are critical to determining the feasibility and strategy for in situ groundwater bioremediation. Hydraulic conductivity and redox conditions, including concentrations of terminal electron acceptors are critical to determine the feasibility and strategy for potential bioremediation applications. Conceptual models followed by characterization and subsequent numerical models are critical for efficient and cost effective bioremediation. Critical research needs in this area include better modeling and integration of remediation strategies with natural attenuation.

  3. Response of Pearl Millet to nitrogen as affected by water deficit

    OpenAIRE

    Diouf , O.; Brou , Yao Télesphore; Diouf , M.; Sarr , B.; Eyletters , M.; Roy-Macauley , H.; Delhaye , J.

    2004-01-01

    International audience; In the Sahelian zone, low soil N could be as limiting as drought in pearl millet production. Although growth and crop productivity depend on several biochemical reactions in which the nitrogen metabolism plays a great role, there is little information available on how N uptake and key enzymes, nitrate reductase and glutamine synthetase, are affected by nitrogen and water interaction in millet. For this purpose, the millet variety cv. Souna III was grown in the field du...

  4. Roostocks/Scion/Nitrogen Interactions Affect Secondary Metabolism in the Grape Berry

    OpenAIRE

    Habran, Aude; Commisso, Mauro; Helwi, Pierre; Hilbert, Ghislaine; Negri, Stefano; Ollat, Nathalie; Gom?s, Eric; van Leeuwen, Cornelis; Guzzo, Flavia; Delrot, Serge

    2016-01-01

    ABSTRACT : The present work investigates the interactions between soil content, rootstock and scion by focusing on the effects of roostocks and nitrogen supply on grape berry content. Scions of Cabernet Sauvignon (CS) and Pinot Noir (PN) varieties were grafted either on Riparia Gloire de Montpellier (RGM) or 110 Richter (110R) rootstock. The 4 rooststock/scion combinations were fertilized with 3 different levels of nitrogen after fruit set. Both in 2013 and 2014, N supply increased N uptake ...

  5. Nitrogen assimilation in soybean nodules, 1

    International Nuclear Information System (INIS)

    Ohyama, Takuji; Kumazawa, Kikuo

    1980-01-01

    In order to elucidate the pathways to assimilate the ammonia produced by N 2 -fixation in soybean nodules, 15 N-labeled compounds were administered to intact nodules or nodule slices pretreated with various inhibitors of nitrogen assimilation. After exposure to 15 N 2 , 15 N-incorporation into various nitrogenous compounds was investigated in attached nodules injected with methionine sulfoximine (MSX) or azaserine (AS). MSX treatment increased the 15 N content of ammonia more than 6 times, however, depressed 15 N content of most of amides and amino acids. AS treatment enhanced 15 N content of amido-N of glutamine as well as ammonia, but decreased amino-N of glutamine and most of amino acids. Experiments with nodule slices pretreated with MSX or AS solution and then fed with 15 N-labeled ammonia or amido- 15 N of glutamine showed the same trends. Aminooxyacetate inhibited nitrogen flow from glutamic acid to other amino acids. These results strongly indicate that the ammonia produced by N 2 -fixation is assimilated by GS/GOGAT system to glutamic acid and then transaminated to various amino acids in situ. 15 N-incorporation patterns in nodule slices fed with 15 N-labeled ammonia, hydroxylamine, nitrite were similar, but nitrate seemed to be reduced in a definite compartment and assimilated similarly as in intact nodules fed with 15 N 2 (author)

  6. Preferences for different nitrogen forms by coexisting plant species and soil microbes.

    Science.gov (United States)

    Harrison, Kathryn A; Bol, Roland; Bardgett, Richard D

    2007-04-01

    The growing awareness that plants might use a variety of nitrogen (N) forms, both organic and inorganic, has raised questions about the role of resource partitioning in plant communities. It has been proposed that coexisting plant species might be able to partition a limited N pool, thereby avoiding competition for resources, through the uptake of different chemical forms of N. In this study, we used in situ stable isotope labeling techniques to assess whether coexisting plant species of a temperate grassland (England, UK) display preferences for different chemical forms of N, including inorganic N and a range of amino acids of varying complexity. We also tested whether plants and soil microbes differ in their preference for different N forms, thereby relaxing competition for this limiting resource. We examined preferential uptake of a range of 13C15N-labeled amino acids (glycine, serine, and phenylalanine) and 15N-labeled inorganic N by coexisting grass species and soil microbes in the field. Our data show that while coexisting plant species simultaneously take up a variety of N forms, including inorganic N and amino acids, they all showed a preference for inorganic N over organic N and for simple over the more complex amino acids. Soil microbes outcompeted plants for added N after 50 hours, but in the long-term (33 days) the proportion of added 15N contained in the plant pool increased for all N forms except for phenylalanine, while the proportion in the microbial biomass declined relative to the first harvest. These findings suggest that in the longer-term plants become more effective competitors for added 15N. This might be due to microbial turnover releasing 15N back into the plant-soil system or to the mineralization and subsequent plant uptake of 15N transferred initially to the organic matter pool. We found no evidence that soil microbes preferentially utilize any of the N forms added, despite previous studies showing that microbial preferences for N forms

  7. Hg uptake in ureteral obstructions

    International Nuclear Information System (INIS)

    Desgrez, J.P.; Bourguignon, M.; Raynaud, C.; CEA, 91 - Orsay

    1976-01-01

    In the presence of a total obstruction the results obtained with the Hg uptake test, as indeed with other functional tests, inform on the value of the kidney function at the time but have no prognostic value where repair possibilities are concerned. Some preliminary results seem to show however that very soon after the obstacle is removed, by the 10th or 15th day perhaps, quantitative functional tests may once more be used to evaluate the functional prognosis. This would mean that by waiting about two weeks after the disappearance of a total obstruction the Hg uptake test may again be used in all confidence. In order to check this deduction, which is based on slender evidence but which nevertheless has important practical implications, the measurement of the Hg uptake rate during the days following removal of the obstacle appears essential. In long-standing partial obstructions the Hg uptake rate gives an accurate assessment of the functional balance and helps considerably in the choice of therapy [fr

  8. Cellular uptake of metallated cobalamins

    DEFF Research Database (Denmark)

    Tran, Mai Thanh Quynh; Stürup, Stefan; Lambert, Ian Henry

    2016-01-01

    Cellular uptake of vitamin B12-cisplatin conjugates was estimated via detection of their metal constituents (Co, Pt, and Re) by inductively coupled plasma mass spectrometry (ICP-MS). Vitamin B12 (cyano-cob(iii)alamin) and aquo-cob(iii)alamin [Cbl-OH2](+), which differ in the β-axial ligands (CN...

  9. Tumor uptake of radioruthenium compounds

    International Nuclear Information System (INIS)

    Srivastava, S.C.; Richards, P.; Meinken, G.E.; Larson, S.M.; Grunbaum, Z.

    1980-01-01

    The use of ruthenium-97 as a scintigraphic agent, particularly for tumor localization, is investigated. The tumor uptake of ruthenium chloride and ruthenium-labelled transferrin is evaluated and their application as tumor-imagine agents is compared to gallium-67 citrate

  10. Octreotide Uptake in Parathyroid Adenoma

    Directory of Open Access Journals (Sweden)

    Seyhan Karaçavuş

    2012-08-01

    Full Text Available The patient with a history of bone pain and muscle weakness, was thought to have oncogenic osteomalacia as a result of biochemical investigations and directed to Nuclear Medicine Department for a whole-body bone scintigraphy and 111In-octreotide scintigraphy. There was no focal pathologic tracer uptake, but generalized marked increase in skeletal uptake on bone scintigraphy. Octreotide scintigraphy showed accumulation of octreotide in the region of the left lobe of the thyroid gland in the neck. Thereafter, parathyroid scintigraphy was performed with technetium-99m labeled metroxy-isobutyl-isonitryl (99mTc-MIB and MIBI scan demonstrated radiotracer uptake at the same location with octreotide scintigraphy. The patient underwent left inferior parathyroidectomy and histopathology confirmed a parathyroid adenoma. Somatostatin receptor positive parathyroid adenoma may show octreotide uptake. Octreotide scintigraphy may be promising and indicate a possibility of using somatostatin analogues for the medical treatment of somatostatin receptor positive parathyroid tumors. (MIRT 2012;21:77-79

  11. Ocean carbon uptake and storage

    International Nuclear Information System (INIS)

    Tilbrook, Bronte

    2007-01-01

    Full text: The ocean contains about 95% of the carbon in the atmosphere, ocean and land biosphere system, and is of fundamental importance in regulating atmospheric carbon dioxide concentrations. In the 1990s an international research effort involving Australia was established to determine the uptake and storage of anthropogenic C02 for all major ocean basins. The research showed that about 118 of the 244 + 20 billion tons of the anthropogenic carbon emitted through fossil fuel burning and cement production has been stored in the ocean since preindustrial times, thus helping reduce the rate of increase in atmospheric C02. The research also showed the terrestrial biosphere has been a small net source of C02 (39 ± 28 billion tons carbon) to the atmosphere over the same period. About 60% of the total ocean inventory of the anthropogenic C02 was found in the Southern Hemisphere, with most in the 30 0 S to 50 0 S latitude band. This mid-latitude band is where surface waters are subducted as Mode and Intermediate waters, which is a major pathway controlling ocean C02 uptake. High storage (23% of the total) also occurs in the North Atlantic, associated with deep water formation in that basin. The ocean uptake and storage is expected to increase in the coming decades as atmospheric C02 concentrations rise. However, a number of feedback mechanisms associated with surface warming, changes in circulation, and biological effects are likely to impact on the uptake capacity. The accumulation or storage-of the C02 in the ocean is also the major driver of ocean acidification with potential to disrupt marine ecosystems. This talk will describe the current understanding of the ocean C02 uptake and storage and a new international research strategy to detect how the ocean uptake and storage will evolve on interannual through decadal scales. Understanding the ocean response to increasing atmospheric C02 will be a key element in managing future C02 increases and establishing

  12. Sex in situ

    DEFF Research Database (Denmark)

    Krøgholt, Ida

    2017-01-01

    Sex er en del af vores sociale praksis og centralt for det, vi hver især er. Men bortset fra pornoindustrien, har vi ikke mange muligheder for at få adgang til billeder af sex. Teater Nordkrafts forestilling Sex in situ vil gøre seksuelle billeder til noget, der kan deles, udveksles og tales om, og...

  13. Phosphorus effect on the uptake, translocation and accumulation of the 14C-urea in orchard grass (Dactylis glomerata L.)

    International Nuclear Information System (INIS)

    Panak, H.; Nowak, G.; Nowak, J.; Akademia Rolniczo-Technicza, Olsztyn

    1981-01-01

    The effect of different phosphorus supplies on the uptake, translocation and accumulation of 14 C-urea by orchard grass was investigated. Phosphorus starvation inhibits the uptake, translocation and accumulation of the carbon of urea similarly to the nitrogen of urea. As compared with the uptake process the reduction of the accumulation is much more effected by the inhibition of the carbon translocation from roots to the aboveground parts. Lack of phosphorus also decreases the incorporation of the 14 C of urea into high-molecular compounds. The effect of phosphorus deficit on the accumulation of 14 C-urea increases with time of starvation. (orig.)

  14. Development of portable HPGe spectrometer for in situ measurements

    Directory of Open Access Journals (Sweden)

    Kail Artjoms

    2015-01-01

    Full Text Available In situ applications require a very high level of portability of high-resolution spectrometric equipment. Usage of HPGe detectors for radioactivity measurements in the environment or for nuclear safeguard applications, to combat illicit trafficking of nuclear materials or uranium and plutonium monitoring in nuclear wastes, has become a norm in the recent years. Portable HPGe-based radionuclide spectrometer with electrical cooling has lately appeared on the market for in situ applications. At the same time deterioration of energy resolution associated with vibrations produced by cryocooler or high weight of the instrument, short time of autonomous operation and high price of these spectrometers are limiting their usage in many cases. In this paper we present development results of ultra compact hand held all-in-one spectrometer for in situ measurements based on HPGe detector cooled by liquid nitrogen without listing the above disadvantages.

  15. FDG uptake in the stomach

    International Nuclear Information System (INIS)

    Yun, M. J.; Cho, H. J.; Cho, E. H.; Kim, T. S.; Kang, W. J.; Lee, J. D.

    2007-01-01

    This study was performed to evaluate histopathologic features of advanced gastric cancer (AGC) to predict FDG uptake on PET. 153 patients(102 men; mean age, 55 y) were diagnosed with AGC by surgery were included in this study. PET images were evaluated by visual and semi-quantitative analysis of FDG uptake in primary tumors. Primary tumors size were measured and divided according to Borrmann classification. Tumor histology was classified under WHO classification, depth of invasion and Iymphovascular invasion. The tumors were also grouped by high cellular(cellularity = 50%) and low cellular group (<50%). Microscopic growth type was based on Lauren classification. Stromal fibrosis degree and inflammatory cell infiltration amount was graded as low(none∼mild), or high(moderate∼severe). Lymph node metastases was assessed in all patients. Statistical analyses were performed to evaluate differences in SUV as to histopathologic factors. Of the 153 patients, 21 patients(14%) had primary tumor invisible on initial whole body images. After water ingestion, the tumors became visible in 15 of the 21 patients due to disappearance of physiologic stomach uptake. Polypoid or ulcerofungating tumors, high cellularity, intestinal growth pattern, and larger tumors significantly predicted increased tumor SUVs. Well or moderately differentiated adenocarcinoma tended to show high cellularity and intestinal growth pattern. Poorly differentiated adenocarcinoma had diverse spectrum of histopathology. Signet ring cell carcinomas were mostly ulceroinfiltrative or diffusely infiltrative in macroscopic type and diffuse in microscopic tumor growth. Mucinous adenocarcinomas were mostly low in cellularity. FDG uptake patterns are useful in representing histopathologic characteristics of the entire tumor in gastric cancers. The degree of FDG uptake depends on tumor size, macroscopic type, cellularity, and microscopic growth pattern and it shows no association with well known important prognostic

  16. Studies of the efficiency of nitrogen placement methods and slow release nitrogen fertilizers for rice and wheat, using N-15 labelled fertilizers

    International Nuclear Information System (INIS)

    Shaukat, A.

    1979-12-01

    A series of experiments with rice and wheat were carried out to study the efficiency of nitrogen placement methods and slow-release nitrogen fertilizers for these two crops using N-15-labelled fertilizer. The results show that (1) reduced N levels, of the order of 75 percent of the full recommended dose, are equally efficient as the full dose for wheat. The yield of rice grain increased with the increased dose of nitrogen; (2) Point placement of fertilizers for rice was superior to broadcast application in terms of uptake and yield. For optimum yield of wheat grain, urea should perferably be applied as a single dose banded between the rows at 5 cm depth or by broadcasting and incorporation in the soil at the time of sowing; (3) Sulphur-coated urea (SCU) at a comparable dose and mode of application gave better yields of rice grain than the application of urea and IBDU (Isobutylidine Diurea); (4) More nitrogen was taken up by wheat when SCU was applied. The best uptake was when it was applied half at sowing and half at tillering. The nitrogen uptake from the SCU by point placement was better for rice plants than broadcast application and was higher in magnitude than the IBDU

  17. Reassessing carbon sequestration in the North China Plain via addition of nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Wenxu, E-mail: dongwx@sjziam.ac.cn [Key Laboratory of Agricultural Water Resources, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang 050021 (China); Duan, Yongmei, E-mail: 106086193@QQ.com [Geological Survey of Jiangxi Province, Nanchang 330030 (China); Wang, Yuying, E-mail: wangyy@sjziam.ac.cn [Key Laboratory of Agricultural Water Resources, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang 050021 (China); Hu, Chunsheng, E-mail: cshu@sjziam.ac.cn [Key Laboratory of Agricultural Water Resources, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang 050021 (China)

    2016-09-01

    Soil inorganic carbon (SIC) exerts a strong influence on the carbon (C) sequestered in response to nitrogen (N) additions in arid and semi-arid ecosystems, but limited information is available on in situ SIC storage and dissolution at the field level. This study determined the soil organic/inorganic carbon storage in the soil profile at 0–100 cm depths and the concentration of dissolved inorganic carbon (DIC) in soil leachate in 4 N application treatments (0, 200, 400, and 600 kg N ha{sup −1} yr{sup −1}) for 15 years in the North China Plain. The objectives were to evaluate the effect of nitrogen fertilizer on total amount of carbon sequestration and the uptake of atmospheric CO{sub 2} in an agricultural system. Results showed that after 15 years of N fertilizer application the SOC contents at depths of 0–100 cm significantly increased, whereas the SIC contents significantly decreased at depths of 0–60 cm. However, the actual measured loss of carbonate was far higher than the theoretical maximum values of dissolution via protons from nitrification. Furthermore, the amount of HCO{sub 3}{sup −} and the HCO{sub 3}{sup −} / (Ca{sup 2+} + Mg{sup 2+}) ratio in soil leachate were higher in the N application treatments than no fertilizer input (CK) for the 0–80 cm depth. The result suggested that the dissolution of carbonate was mainly enhanced by soil carbonic acid, a process which can absorb soil or atmosphere CO{sub 2} and less influenced by protons through the nitrification which would release CO{sub 2}. To accurately evaluate soil C sequestration under N input scenarios in semi-arid regions, future studies should include both changes in SIC storage as well as the fractions of dissolution with different sources of acids in soil profiles. - Highlights: • The SOC contents significantly increased after long-term nitrogen application, while SIC decreased. • The measured loss of carbonate was far higher than the theoretical values of dissolution from

  18. Uptake of DNA by cancer cells without a transfection reagent

    Directory of Open Access Journals (Sweden)

    Yanping Kong

    Full Text Available Abstract Background Cancer cells exhibit elevated levels of glucose uptake and may obtain pre-formed, diet-derived fatty acids from the bloodstream to boost their rapid growth; they may also use nucleic acid from their microenvironment. The study of processing nucleic acid by cancer cells will help improve the understanding of the metabolism of cancer. DNA is commonly packaged into a viral or lipid particle to be transferred into cells; this process is called transfection in laboratory. Cancer cells are known for having gene mutations and the evolving ability of endocytosis. Their uptake of DNAs might be different from normal cells; they may take in DNAs directly from the environment. In this report, we studied the uptake of DNAs in cancer cells without a transfection reagent. Methods A group of DNA fragments were prepared with PCR and labeled with isotope phosphorous-32 to test their uptake by Huh 7 (liver cancer and THLE3 (normal liver cells after incubation overnight by counting radioactivity of the cells’ genomic DNA. Multiple cell lines including breast cancer and lung cancer were tested with the same method. DNA molecules were also labeled with fluorescence to test the location in the cells using a kit of “label it fluorescence in situ hybridization (FISH” from Mirus (USA. Results The data demonstrated that hepatocellular carcinoma cells possess the ability to take in large DNA fragments directly without a transfection reagent whereas normal liver cells cannot. Huh7 and MDA-MB231 cells displayed a significantly higher Rhodamine density in the cytoplasmic phagosomes and this suggests that the mechanism of uptake of large DNA by cancer cells is likely endocytosis. The efficacy of uptake is related to the DNA’s size. Some cell lines of lung cancer and breast cancer also showed similar uptake of DNA. Conclusions In the present study, we have revealed the evidence that some cancer cells, but not nontumorigenic cells, can take DNA

  19. The nitrogen cycle: Atmosphere interactions

    Science.gov (United States)

    Levine, J. S.

    1984-01-01

    Atmospheric interactions involving the nitrogen species are varied and complex. These interactions include photochemical reactions, initiated by the absorption of solar photons and chemical kinetic reactions, which involve both homogeneous (gas-to-gas reactions) and heterogeneous (gas-to-particle) reactions. Another important atmospheric interaction is the production of nitrogen oxides by atmospheric lightning. The nitrogen cycle strongly couples the biosphere and atmosphere. Many nitrogen species are produced by biogenic processes. Once in the atmosphere nitrogen oxides are photochemically and chemically transformed to nitrates, which are returned to the biosphere via precipitation, dry deposition and aerosols to close the biosphere-atmosphere nitrogen cycle. The sources, sinks and photochemistry/chemistry of the nitrogen species; atmospheric nitrogen species; souces and sinks of nitrous oxide; sources; sinks and photochemistry/chemistry of ammonia; seasonal variation of the vertical distribution of ammonia in the troposphere; surface and atmospheric sources of the nitrogen species, and seasonal variation of ground level ammonia are summarized.

  20. Bicarbonate uptake by marine Crenarchaeota

    NARCIS (Netherlands)

    Wuchter, C.; Schouten, S.; Boschker, H.T.S.; Sinninghe Damsté, J.S.

    2003-01-01

    Biphytanyl membrane lipids and 16S rRNA sequences derived from marine Crenarchaeota were detected in shallow North Sea surface water in February 2002. To investigate the carbon fixation mechanism of these uncultivated archaea in situ 13C bicarbonate tracer experiments were performed with this water