WorldWideScience

Sample records for maize water uptake

  1. Root type matters: measurements of water uptake by seminal, crown and lateral roots of maize

    Science.gov (United States)

    Ahmed, Mutez Ali; Zarebanadkouki, Mohsen; Kaestner, Anders; Carminati, Andrea

    2016-04-01

    Roots play a key role in water acquisition and are a significant component of plant adaptation to different environmental conditions. Although maize (Zea mays L.) is one of the most important crops worldwide, there is limited information on the function of different root segments and types in extracting water from soils. Aim of this study was to investigate the location of root water uptake in mature maize. We used neutron radiography to image the spatial distribution of maize roots and trace the transport of injected deuterated water (D2O) in soil and roots. Maize plants were grown in aluminum containers filled with a sandy soil that was kept homogeneously wet throughout the experiment. When the plants were five weeks-old, we injected D2O into selected soil regions. The transport of D2O was simulated using a diffusion-convection numerical model. By fitting the observed D2O transport we quantified the diffusion coefficient and the water uptake of the different root segments. The model was initially developed and tested with two weeks-old maize (Ahmed et. al. 2015), for which we found that water was mainly taken up by lateral roots and the water uptake of the seminal roots was negligible. Here, we used this method to measure root water uptake in a mature maize root system. The root architecture of five weeks-old maize consisted of primary and seminal roots with long laterals and crown (nodal) roots that emerged from the above ground part of the plant two weeks after planting. The crown roots were thicker than the seminal roots and had fewer and shorter laterals. Surprisingly, we found that the water was mainly taken up by the crown roots and their laterals, while the lateral roots of seminal roots, which were the main location of water uptake of younger plants, stopped to take up water. Interestingly, we also found that in contrast to the seminal roots, the crown roots were able to take up water also from their distal segments. We conclude that for the two weeks

  2. Measurements of water uptake of maize roots: the key function of lateral roots

    Science.gov (United States)

    Ahmed, M. A.; Zarebanadkouki, M.; Kroener, E.; Kaestner, A.; Carminati, A.

    2014-12-01

    Maize (Zea mays L.) is one of the most important crop worldwide. Despite its importance, there is limited information on the function of different root segments and root types of maize in extracting water from soils. Therefore, the aim of this study was to investigate locations of root water uptake in maize. We used neutron radiography to: 1) image the spatial distribution of maize roots in soil and 2) trace the transport of injected deuterated water (D2O) in soil and roots. Maizes were grown in aluminum containers (40×38×1 cm) filled with a sandy soil. When the plants were 16 days old, we injected D2O into selected soil regions containing primary, seminal and lateral roots. The experiments were performed during the day (transpiring plants) and night (not transpiring plants). The transport of D2O into roots was simulated using a new convection-diffusion numerical model of D2O transport into roots. By fitting the observed D2O transport we quantified the diffusional permeability and the water uptake of the different root segments. The maize root architecture consisted of a primary root, 4-5 seminal roots and many lateral roots connected to the primary and seminal roots. Laterals emerged from the proximal 15 cm of the primary and seminal roots. Water uptake occurred primarily in lateral roots. Lateral roots had the highest diffusional permeability (9.4×10-7), which was around six times higher that the diffusional permeability of the old seminal segments (1.4×10-7), and two times higher than the diffusional permeability of the young seminal segments (4.7×10-7). The radial flow of D2O into the lateral (6.7×10-5 ) was much higher than in the young seminal roots (1.1×10-12). The radial flow of D2O into the old seminal was negligible. We concluded that the function of the primary and seminal roots was to collect water from the lateral roots and transport it to the shoot. A maize root system with lateral roots branching from deep primary and seminal roots would be

  3. Using stable isotopes to determine seasonal variations in water uptake of summer maize under different fertilization treatments

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Ying, E-mail: maying@igsnrr.ac.cn [Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, 100101 Beijing (China); State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 210008 Nanjing (China); Song, Xianfang [Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, 100101 Beijing (China)

    2016-04-15

    Fertilization and water both affect root water uptake in the nutrient and water cycle of the Soil-Plant-Atmosphere-Continuum (SPAC). In this study, dual stable isotopes (D and {sup 18}O) were used to determine seasonal variations in water uptake patterns of summer maize under different fertilization treatments in Beijing, China during 2013–2014. The contributions of soil water at different depths to water uptake were quantified by the MixSIAR Bayesian mixing model. Water uptake was mainly sourced from soil water in the 0–20 cm depth at the seeding (67.7%), jointing (60.5%), tasseling (47.5%), dough (41.4%), and harvest (43.9%) stages, and the 20–50 cm depth at the milk stage (32.8%). Different levels of fertilization application led to considerable differences in the proportional contribution of soil water at 0–20 cm (6.0–58.5%) and 20–50 cm (6.1–26.3%). There was little difference of contributions in the deep layers (50–200 cm) among treatments in 2013, whereas differences were observed in 50–90 cm at the milk stage and 50–200 cm at the dough stage during 2014. The main water uptake depth was concentrated in the upper soil layers (0–50 cm) during the wet season (2013), whereas a seasonal drought in 2014 promoted the contribution of soil water in deep layers. The contribution of soil water was significantly and positively correlated with the proportions of root length (r = 0.753, p < 0.01). The changes of soil water distribution were consistent with the seasonal variation in water uptake patterns. The present study identified water sources for summer maize under varying fertilization treatments and provided scientific implications for fertilization and irrigation management. - Highlights: • Dual stable isotopes and MixSIAR were coupled to quantify water uptake of maize. • Maize mainly used soil water in 20–50 cm at milk stage and 0–20 cm at other stages. • Fertilization treatments led to distinct water uptake pattern at 0–50 cm

  4. Using stable isotopes to determine seasonal variations in water uptake of summer maize under different fertilization treatments

    International Nuclear Information System (INIS)

    Ma, Ying; Song, Xianfang

    2016-01-01

    Fertilization and water both affect root water uptake in the nutrient and water cycle of the Soil-Plant-Atmosphere-Continuum (SPAC). In this study, dual stable isotopes (D and "1"8O) were used to determine seasonal variations in water uptake patterns of summer maize under different fertilization treatments in Beijing, China during 2013–2014. The contributions of soil water at different depths to water uptake were quantified by the MixSIAR Bayesian mixing model. Water uptake was mainly sourced from soil water in the 0–20 cm depth at the seeding (67.7%), jointing (60.5%), tasseling (47.5%), dough (41.4%), and harvest (43.9%) stages, and the 20–50 cm depth at the milk stage (32.8%). Different levels of fertilization application led to considerable differences in the proportional contribution of soil water at 0–20 cm (6.0–58.5%) and 20–50 cm (6.1–26.3%). There was little difference of contributions in the deep layers (50–200 cm) among treatments in 2013, whereas differences were observed in 50–90 cm at the milk stage and 50–200 cm at the dough stage during 2014. The main water uptake depth was concentrated in the upper soil layers (0–50 cm) during the wet season (2013), whereas a seasonal drought in 2014 promoted the contribution of soil water in deep layers. The contribution of soil water was significantly and positively correlated with the proportions of root length (r = 0.753, p < 0.01). The changes of soil water distribution were consistent with the seasonal variation in water uptake patterns. The present study identified water sources for summer maize under varying fertilization treatments and provided scientific implications for fertilization and irrigation management. - Highlights: • Dual stable isotopes and MixSIAR were coupled to quantify water uptake of maize. • Maize mainly used soil water in 20–50 cm at milk stage and 0–20 cm at other stages. • Fertilization treatments led to distinct water uptake pattern at 0–50 cm depth

  5. Measurements of water uptake of maize roots: insights for traits that influence water transport from the soil

    Science.gov (United States)

    Ahmed, Mutez A.; Zarebanadkouki, Mohsen; Kroener, Eva; Carminati, Andrea

    2015-04-01

    Water availability is a primary constraint to the global crop production. Although maize (Zea mays L.) is one of the most important crops worldwide, there is limited information on the function of different root segments and types in extracting water from soils. Aim of this study was to investigate the location of water uptake in maize roots. We used neutron radiography to: 1) image the spatial distribution of maize roots in soil and 2) trace the transport of injected deuterated water (D2O) in soil and roots. Maize plants were grown in aluminum containers (40×38×1 cm) filled with sandy soil. The soil was partitioned into different compartments using 1-cm-thick layers of coarse sand. When the plants were two weeks-old we injected D2O into selected soil compartments. The experiments were performed during the day (transpiring plants) and night (non transpiring plants). The transport of D2O into roots was simulated using a convection-diffusion numerical model of D2O transport into roots. By fitting the observed D2O transport we quantified the diffusion coefficient and the water uptake of the different root segments. The maize root architecture consisted of a primary root, 4-5 seminal roots and many lateral roots connected to the primary and seminal roots. Laterals emerged from the proximal 15 cm of the primary and seminal roots. Both during day and night measurements, D2O entered more quickly into lateral roots than into primary and seminal roots. The quick transport of D2O into laterals was caused by the small radius of lateral roots. The diffusion coefficient of lateral roots (4.68×10-7cm2s-1)was similar to that of the distal segments of seminal roots (4.72×10-7cm2s-1) and higher than of the proximal segments (1.42×10-7cm2s-1). Water uptake of lateral roots (1.64×10-5cms-1)was much higher than that of the distal segments of seminal roots (1.18×10-12cms-1). Water uptake of the proximal seminal segments was negligible. We conclude that the function of lateral

  6. Biochar amendment of fluvio-glacial temperate sandy subsoil: Effects on maize water uptake, growth and physiology

    DEFF Research Database (Denmark)

    Ahmed, Fauziatu; Arthur, Emmanuel; Plauborg, Finn

    2018-01-01

    Coarse sandy soils have poor water retention capacity, which may constrain crop growth during drought. We investigated the effect of biochar amendment to subsoil on crop physiological processes and maize yield, comparing irrigated and drought conditions. A two-year greenhouse experiment was condu......Coarse sandy soils have poor water retention capacity, which may constrain crop growth during drought. We investigated the effect of biochar amendment to subsoil on crop physiological processes and maize yield, comparing irrigated and drought conditions. A two-year greenhouse experiment...... was conducted with one-time application of straw biochar at concentrations of 0%, 1%, 2% and 3% (B0, B1, B2 and B3). Maize was planted twice in the same large pots one week and again 12 months after biochar application. Plants were fully irrigated until flowering; thereafter, half of them were subjected...... to drought. Our results indicate B2 and B3 increased soil water content at field capacity. Leaf water potential, stomatal conductance, photosynthesis and transpiration were maintained in B2 and B3 during the drying cycle in year one and in all biochar levels in year two. In the first year, B3 induced...

  7. Uptake, translocation, and toxicity of gold nanorods in maize

    Science.gov (United States)

    Moradi Shahmansouri, Nastaran

    Nanomaterials are widely used in many different products, such as electronics, cosmetics, industrial goods, biomedical uses, and other material applications. The heavy emission of nanomaterials into the environment has motived increasing concern regarding the effects on ecosystems, food chains, and, human health. Plants can tolerate a certain amount of natural nanomaterials, but large amounts of ENMs released from a variety of industries could be toxic to plants and possibly threaten the ecosystem. Employing phytoremediation as a contamination treatment method may show promise. However a pre-requisite to successful treatment is a better understanding of the behavior and effects of nanomaterials within plant systems. This study is designed to investigate the uptake, translocation, bioavailability, and toxicity of gold nanorods in maize plants. Maize is an important food and feed crop that can be used to understand the potential hazardous effects of nanoparticle uptake and distribution in the food chain. The findings could be an important contribution to the fields of phytoremediation, agri-nanotechnology, and nanoparticle toxicity on plants. In the first experiment, hydroponically grown maize seedlings were exposed to similar doses of commercial non-coated gold nanorods in three sizes, 10x34 nm, 20x75 nm, and 40x96 nm. The three nanorod species were suspended in solutions at concentrations of 350 mg/l, 5.8 mg/l, and 14 mg/l, respectively. Maize plants were exposed to all three solutions resulting in considerably lower transpiration and wet biomass than control plants. Likewise, dry biomass was reduced, but the effect is less pronounced than that of transpiration and wet biomass. The reduced transpiration and water content, which eventually proved fatal to exposed plants, were most likely a result of toxic effect of gold nanorod, which appeared to physically hinder the root system. TEM images proved that maize plants can uptake gold particles and accumulate them in

  8. Is there a strategy I iron uptake mechanism in maize?

    Science.gov (United States)

    Li, Suzhen; Zhou, Xiaojin; Chen, Jingtang; Chen, Rumei

    2018-04-03

    Iron is a metal micronutrient that is essential for plant growth and development. Graminaceous and nongraminaceous plants have evolved different mechanisms to mediate Fe uptake. Generally, strategy I is used by nongraminaceous plants like Arabidopsis, while graminaceous plants, such as rice, barley, and maize, are considered to use strategy II Fe uptake. Upon the functional characterization of OsIRT1 and OsIRT2 in rice, it was suggested that rice, as an exceptional graminaceous plant, utilizes both strategy I and strategy II Fe uptake systems. Similarly, ZmIRT1 and ZmZIP3 were identified as functional zinc and iron transporters in the maize genome, along with the determination of several genes encoding Zn and Fe transporters, raising the possibility that strategy I Fe uptake also occurs in maize. This mini-review integrates previous reports and recent evidence to obtain a better understanding of the mechanisms of Fe uptake in maize.

  9. Uptake, translocation, and debromination of polybrominated diphenyl ethers in maize

    Institute of Scientific and Technical Information of China (English)

    Moming Zhao; Shuzhen Zhang; Sen Wang; Honglin Huang

    2012-01-01

    Uptake,translocation and debromination of three polybrominated diphenyl ethers(PBDEs),BDE-28,-47 and-99,in maize were studied in a hydroponic experiment.Roots took up most of the PBDEs in the culture solutions and more highly brominated PBDEs had a stronger uptake capability.PBDEs were detected in the stems and leaves of maize after exposure but rarely detected in the blank control plants.Furthermore,PBDE concentrations decreased from roots to stems and then to leaves,and a very clear decreasing gradient was found in segments upwards along the stem.These altogether provide substantiating evidence for the acropetal translocation of PBDEs in maize.More highly brominated PBDEs were translocated with more difficulty.Radial translocation of PBDEs from nodes to sheath inside maize was also observed.Both acropetal and radial translocations were enhanced at higher transpiration rates,suggesting that PBDE transport was probably driven by the transpiration stream.Debromination of PBDEs occurred in all parts of the maize,and debromination patterns of different parent PBDEs and in different parts of a plant were similar but with some differences.This study for the first time provides direct evidence for the acropetal translocation of PBDEs within plants,elucidates the process of PBDE transport and clarifies the debromination products of PBDEs in maize.

  10. Facilitation of phosphorus uptake in maize plants by mycorrhizosphere bacteria

    DEFF Research Database (Denmark)

    Battini, Fabio; Grønlund, Mette; Agnolucci, Monica

    2017-01-01

    availability of soil P. This study investigated whether biofertilizers and bioenhancers, such as arbuscular mycorrhizal fungi (AMF) and their associated bacteria could enhance growth and P uptake in maize. Plants were grown with or without mycorrhizas in compartmented pots with radioactive P tracers and were...

  11. Comparative study of the radionuclide uptake and distribution within plants for barley and maize varieties

    International Nuclear Information System (INIS)

    Kostyuk, O.

    1998-01-01

    Differences in the Cs-134 and Sr-85 uptake by three barley and two maize varieties were investigated in a water culture experiment. In barley, the maximum differences were about 30% for cesium and 50% for strontium. The differences between the maize varieties were negligible. The maximum difference between the varieties of the two species of crops was approximately 30% for cesium and 1 70% for strontium with higher radionuclide uptake by maize. All barley varieties accumulated cesium nearly 3.5 times more effectively than strontium, whereas for the maize varieties, cesium was accumulated about 2 times more effectively. There is a large difference in the radionuclide distribution within the plants: the amount of radiocesium in the green part of plants of both species was approximately 30% of the total, while for radiostrontium it was about 80%. As a result, approximately the same amount of the radionuclides were present in the green part of plants, despite the large difference in the uptake of the radionuclides by the whole plants. It is concluded that crop selection as a provision to reduce radionuclide contamination of the food chain should only be applied taking into account the different radionuclide distributions within the plants

  12. Characteristics of sugar uptake by immature maize embryos

    International Nuclear Information System (INIS)

    Griffith, S.M.; Jones, R.J.; Brenner, M.L.

    1986-01-01

    Characteristics of sugar uptake by immature maize embryos were determined in vitro utilizing a 14 C-sugar solution incubation method. Hexose uptake rates were greater than those for sucrose, however, all showed biphasic kinetics. Glucose and fructose saturable components were evidence at <50 mM and sucrose at <5 mM. Chemical inhibitors (CCCP, DNP, NaCN, and PCMBS) and low temperature reduced sugar uptake. Sucrose influx was pH dependent while glucose was not. Embryos maintained a high sucrose to hexose ratio throughout development. At 25 days after pollination sucrose levels exceeded 200 mM while hexose levels remained below 5 mM. Glucose was rapidly converted to sucrose upon transport into the embryo. These circumstantial data indicate that sugar uptake by immature maize embryos is metabolically dependent and carrier mediated. Furthermore, sucrose transport appears to occur against its concentration gradient involving a H+/sucrose cotransport mechanism, while glucose influx is driven by its concentration gradient and subsequent metabolism

  13. 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...

  14. Effect of different iron levels on 65Zn uptake and transport in maize seedlings

    International Nuclear Information System (INIS)

    Rathore, V.S.; Sharma, D.; Kandala, J.C.

    1974-01-01

    Uptake and translocation of 65 Zn was studied in two week old maize seedlings at 0.01, 0.1, 1 and 5 ppm iron levels in half-strength Hoagland's solution. Four different zinc levels viz., 0.04, 0.4, 4 and 8 ppm were taken. Total 65 Zn uptake and translocation to shoots at 2, 4, 6 and 12 hours showed that increasing iron levels in the uptake medium reduced Zn-uptake in all combinations and at all uptake hours studied. This antagnnistic effect of iron on zinc uptake was more pronounced at the initial stages and could be partly inhibited by increasing zinc concentration in the uptake medium. Translocation of 65 Zn to shoots increased with increase in uptake time. Increasing iron levels in the medium decreased zinc dislocation to shoots at all zinc levels. (author)

  15. Impact of chelator-induced phytoextraction of cadmium on yield and ionic uptake of maize.

    Science.gov (United States)

    Anwar, Sumera; Khan, Shahbaz; Ashraf, M Yasin; Noman, Ali; Zafar, Sara; Liu, Lijun; Ullah, Sana; Fahad, Shah

    2017-06-03

    Enhanced phytoextraction uses soil chelators to increase the bioavailability of heavy metals. This study tested the effectiveness of ethylenediaminetetraacetic acid (EDTA) and citric acid in enhancing cadmium (Cd) phytoextraction and their effects on the growth, yield, and ionic uptake of maize (Zea mays). Maize seeds of two cultivars were sown in pots treated with 15 (Cd 15 ) or 30 mg Cd kg -1 soil (Cd 30 ). EDTA and citric acid at 0.5 g kg -1 each were applied 2 weeks after germination. Results demonstrated that the growth, yield per plant, and total grain weight were reduced by exposure to Cd. EDTA increased the uptake of Cd in shoots, roots, and grains of both maize varieties. Citric acid did not enhance the uptake of Cd, rather it ameliorated the toxicity of Cd, as shown by increased shoot and root length and biomass. Cadmium toxicity reduced the number of grains, rather than the grain size. The maize cultivar Sahiwal-2002 extracted 1.6% and 3.6% of Cd from soil in both Cd+ EDTA treatments. Hence, our study implies that maize can be used to successfully phytoremediate Cd from soil using EDTA, without reducing plant biomass or yield.

  16. Maize nutrient uptake affected by genotype and fertilization

    Directory of Open Access Journals (Sweden)

    Đalović Ivica

    2015-01-01

    Full Text Available The content of nutrients in maize are commonly related with fertilization and soil quality and rarely explained with the individual hybrid properties. Therefore, the aim of this study is to access a long term fertilization system on ear leaf of Mg, Fe, Mn and Cu content in six maize hybrids(NS 3014, NS 4015, NS 5043, NS 6010, NS 6030 and NS 7020. Samples were collected from a long-term experiment at the Rimski Šančevi experimental field of the Institute of Field and Vegetable Crops in Novi Sad. The study included maize monoculture and 2-year rotations with the application of NPK and manure. Results showed that ear Mg content was influenced with the treatments, hybrid and their interaction and ranged from 1.77-2.69 g kg-1. Iron variability was significantly affected with the treatments and interaction (hybrid x treatments in range from 103.2 to151.9g kg-1. The ear manganese content (41.1-63.6g kg-1 derived from treatments and hybrid effect and Cu (12.3-23.6 g kg-1 was significantly influenced with treatments. Across all treatments, in average, NS6030 had higher values of nutrient and NS3014 was lower in ear nutrient content. This indicates that vegetation length could favor nutrient accumulation. Obtained results suggested that even on fairly productive soil such as Chernozem hybrid selection and the balanced fertilization is crucial for managing the maize nutrient content. [Projekat Ministarsva nauke Republike Srbije, br. TR031073

  17. 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)

  18. Uptake of seed-applied copper by maize and the effects on seed vigor

    Directory of Open Access Journals (Sweden)

    Marcos Altomani Neves Dias

    2015-01-01

    Full Text Available Seed treatment is a low-cost and efficacious method to deliver a diversity of compounds to field crops. This study evaluated the uptake of seed-applied Cu by maize and the effect on seed vigor. The treatments were composed of a control (untreated seeds and five dosages of Cu: 0.11, 0.22, 0.44, 0.88 and 1.76 mg Cu seed–1, applied as cuprous oxide and copper oxychloride formulations. Seedling emergence and the speed of seedling emergence were determined in three periods: 1, 60 and 120 days after Cu application. Evaluations of root and shoot dry mass, Cu tissue concentration and efficiencies of Cu uptake and incorporation were conducted with two-leaf stage maize plants. Seed-applied Cu reduces the speed of maize seedling emergence, while the final emergence percentage is not affected. Shoot dry mass tends to increase with the application of Cu, while there is no interference on root dry mass within the dosages tested. Cu tissue concentration of both roots and shoots increases as higher dosages of Cu are applied to seeds, with higher accumulation in roots. Cuprous oxide promotes higher uptake of Cu by maize roots compared to copper oxychloride.

  19. Effect of Thorium on Growth and Uptake of Some Elements by Maize Plant

    International Nuclear Information System (INIS)

    Al-Shobaki, M.E.E.

    2012-01-01

    A pot experiment (sand culture) was carried out to investigate the effect of thorium on maize dry matter yield, contents and uptake of N,P ,K, Na and Fe and thorium accumulation in maize plant.The pots were contaminated by thorium as Thorium Nitrate(Th (NO 3 ) 4 ,H 2 O)at concentrations 0,5,10,11,12,13,14,15 and 50 ppm. Pots irrigated by 1/10 Hogland solution for 15 days, increased tol/4 Hogland solution after that.The results show that the dry matter (shoot, root and whole plant)decreased with increasing thorium concentration in soil up to 12 ppm and slightly increased with increasing Th to 13 ppm . The Nitrogen content and its uptake decreased with increasing thorium concentration in media growth up to 11 ppm .They were slightly increased at Th concentration between 11-14 ppm in maize shoot and root. The shoots always contained N-content and uptake more than that found in roots . P- uptake decreased in both shoots and roots with increasing in thorium concentration in media growth.

  20. Yield advantage and water saving in maize/pea intercrop

    NARCIS (Netherlands)

    Mao, L.; Zhang, L.; Li, W.; Werf, van der W.; Sun, J.; Spiertz, J.H.J.; Li, L.

    2012-01-01

    Intercropping is a well-established strategy for maximization of yield from limited land, but mixed results have been obtained as to its performance in terms of water use efficiency. Here, two maize/pea intercrop layouts were studied in comparison to sole maize and sole pea with and without plastic

  1. Growing sensitivity of maize to water scarcity under climate change.

    Science.gov (United States)

    Meng, Qingfeng; Chen, Xinping; Lobell, David B; Cui, Zhenling; Zhang, Yi; Yang, Haishun; Zhang, Fusuo

    2016-01-25

    Climate change can reduce crop yields and thereby threaten food security. The current measures used to adapt to climate change involve avoiding crops yield decrease, however, the limitations of such measures due to water and other resources scarcity have not been well understood. Here, we quantify how the sensitivity of maize to water availability has increased because of the shift toward longer-maturing varieties during last three decades in the Chinese Maize Belt (CMB). We report that modern, longer-maturing varieties have extended the growing period by an average of 8 days and have significantly offset the negative impacts of climate change on yield. However, the sensitivity of maize production to water has increased: maize yield across the CMB was 5% lower with rainfed than with irrigated maize in the 1980s and was 10% lower (and even >20% lower in some areas) in the 2000s because of both warming and the increased requirement for water by the longer-maturing varieties. Of the maize area in China, 40% now fails to receive the precipitation required to attain the full yield potential. Opportunities for water saving in maize systems exist, but water scarcity in China remains a serious problem.

  2. Sugar uptake and starch biosynthesis by slices of developing maize endosperm

    International Nuclear Information System (INIS)

    Felker, F.C.; Liu, Kangchien; Shannon, J.C.

    1990-01-01

    14 C-Sugar uptake and incorporation into starch by slices of developing maize (Zea mays L.) endosperm were examined and compared with sugar uptake by maize endosperm-derived suspension cultures. Rates of sucrose, fructose, and D- and L-glucose uptake by slices were similar, whereas uptake rates for these sugars differed greatly in suspension cultures. Concentration dependence of sucrose, fructose, and D-glucose uptake was biphasic (consisting of linear plus saturable components) with suspension cultures but linear with slices. These and other differences suggest that endosperm slices are freely permeable to sugars. After diffusion into the slices, sugars were metabolized and incorporated into starch. Starch synthesis, but not sugar accumulation, was greatly reduced by 2.5 millimolar p-chloromercuribenzenesulfonic acid and 0.1 millimolar carbonyl cyanide m-chlorophenylhydrazone. Starch synthesis was dependent on kernel age and incubation temperature, but not on external pH (5 through 8). Competing sugars generally did not affect the distribution of 14 C among the soluble sugars extracted from endosperm slices incubated in 14 C-sugars. Competing hexoses reduced the incorporation of 14 C into starch, but competing sucrose did not, suggesting that sucrose is not a necessary intermediate in starch biosynthesis. The bidirectional permeability of endosperm slices to sugars makes the characterization of sugar transport into endosperm slices impossible, however the model system is useful for experiments dealing with starch biosynthesis which occurs in the metabolically active tissue

  3. Water transfer in an alfalfa/maize association

    International Nuclear Information System (INIS)

    Corak, S.J.; Blevins, D.G.; Pallardy, S.G.

    1987-01-01

    The authors investigated the possibility of interspecific water transfer in an alfalfa (Medicago sativa L.) and maize (Zea mays L.) association. An alfalfa plant was grown through two vertically stacked plastic tubes. A 5 centimeter air gap between tubes was bridged by alfalfa roots. Five-week old maize plants with roots confined to the top tube were not watered, while associated alfalfa roots had free access to water in the bottom tube (the -/+ treatment). Additional treatments included: top and bottom tubes watered (+/+), top and bottom tubes droughted (-/-), and top tube droughted after removal of alfalfa root bridges and routine removal of alfalfa tillers (-*). Predawn leaf water potential of maize in the -/+ treatment fell to -1.5 megapascals 13 days after the start of drought; thereafter, predawn and midday potentials were maintained near -1.9 megapascals. Leaf water potentials of maize in the -/- and -* treatments declined steadily; all plants in these treatments were completely desiccated before day 50. High levels of tritium activity were detected in water extracted from both alfalfa and maize leaves after 3 H 2 O was injected into the bottom -/+ tube at day 70 or later. Maize in the -/+ treatment was able to survive an otherwise lethal period of drought by utilizing water lost by alfalfa roots

  4. Phosphate Uptake from Phytate Due to Hyphae-Mediated Phytase Activity by Arbuscular Mycorrhizal Maize.

    Science.gov (United States)

    Wang, Xin-Xin; Hoffland, Ellis; Feng, Gu; Kuyper, Thomas W

    2017-01-01

    Phytate is the most abundant form of soil organic phosphorus (P). Increased P nutrition of arbuscular mycorrhizal plants derived from phytate has been repeatedly reported. Earlier studies assessed acid phosphatase rather than phytase as an indication of mycorrhizal fungi-mediated phytate use. We investigated the effect of mycorrhizal hyphae-mediated phytase activity on P uptake by maize. Two maize ( Zea mays L.) cultivars, non-inoculated or inoculated with the arbuscular mycorrhizal fungi Funneliformis mosseae or Claroideoglomus etunicatum , were grown for 45 days in two-compartment rhizoboxes, containing a root compartment and a hyphal compartment. The soil in the hyphal compartment was supplemented with 20, 100, and 200 mg P kg -1 soil as calcium phytate. We measured activity of phytase and acid phosphatase in the hyphal compartment, hyphal length density, P uptake, and plant biomass. Our results showed: (1) phytate addition increased phytase and acid phosphatase activity, and resulted in larger P uptake and plant biomass; (2) increases in P uptake and biomass were correlated with phytase activity but not with acid phosphatase activity; (3) lower phytate addition rate increased, but higher addition rate decreased hyphal length density. We conclude that P from phytate can be taken up by arbuscular mycorrhizal plants and that phytase plays a more important role in mineralizing phytate than acid phosphatase.

  5. 14C-incorporation into sugars and organic acids of water-stressed maize leaves

    International Nuclear Information System (INIS)

    Becker, T.; Fock, H.

    1986-01-01

    The incorporation of 14 C into sugars and some organic acids of maize leaves has been studied in relation to the leaf water potential by feeding 14 CO 2 (370 ppm) for 1,2 and 4 min during steady state photosynthesis at 25 0 C (PAR = 800 μmol m -2 s -1 ). The relative specific radioactivity (RSA) of the sugars was low (0.2% after 4 min) at -0.62 MPa (control) and decreased by about 50% when psi dropped to -0.95 MPa. The authors conclude that the low rate of photosynthetic sugar synthesis in maize leaves decreased during water stress. The RSA of malate was extremely low at -0.62 MPa (0.02%). This result may be the consequence of the large pool size of malate in maize leaves. The authors presume that there are two malate pools present in maize leaves, a small metabolic pool and a larger storage pool. The RSA of malate decreased during the stress period. This is consistent with the decline in net CO 2 uptake during water stress. The pool sizes of citrate and isocitrate increased when psi dropped to -0.95 MPa. As practically no radioactivity was detected in these organic acids, they conclude that these compounds are synthesized from unlabelled precursors during water stress

  6. Effects of application of groundnut biomass compost on uptake of phosphorus by maize grown on an Ultisol of South Sulawesi

    Directory of Open Access Journals (Sweden)

    Kasifah

    2014-07-01

    Full Text Available Low crop production is acid dryland area of South Sulawesi is due to low availability of P in the soils. One of alternatives that can be performed to overcome the problems of acid soils having high level of exchangeable Al, is through the addition of organic material. In the upland areas in South Sulawesi, crop rice, maize and groundnut crop residues are readily available, but the crop residues are generally only used as animal feed or even burned. This study was aimed to elucidate the effects of groundnut compost on P uptake by maize in Ultisol of Moncongloe, South Sulawesi. Eight kilograms of air dried soil was mixed with compost according to the following treatments; 0, 10, 15, 20, 25, 30, 35 and 40 t compost/ha. All pots received 200 kg/ha KCl and 300 kg Urea/ha as basal fertilizers. Two maize seeds were planted in each pot and thinned to one plant per pot after one week. At harvest maize shoot dry weight and maize root dry weight, length of maize cop, cob weight, cob diameter, weight grains per cob, P uptake by maize, P content in maize grain, soil available P were measured. Results of the study showed that groundnut compost has the ability to improve the availability of P in the soil and increase P uptake by maize grown on an Ultisol of South Sulawesi. Application of 25 t groundnut compost/ha was the optimal rate that can be used to increase P availability in an Ultisol of South Sulawesi.

  7. Variation for N Uptake System in Maize: Genotypic Response to N Supply

    KAUST Repository

    Garnett, Trevor; Plett, Darren; Conn, Vanessa; Conn, Simon; Rabie, Huwaida; Rafalski, J. Antoni; Dhugga, Kanwarpal; Tester, Mark A.; Kaiser, Brent N.

    2015-01-01

    An understanding of the adaptations made by plants in their nitrogen (N) uptake systems in response to reduced N supply is important to the development of cereals with enhanced N uptake efficiency (NUpE). Twenty seven diverse genotypes of maize (Zea mays, L.) were grown in hydroponics for 3 weeks with limiting or adequate N supply. Genotypic response to N was assessed on the basis of biomass characteristics and the activities of the nitrate (NO−3) and ammonium (NH+4) high-affinity transport systems. Genotypes differed greatly for the ability to maintain biomass with reduced N. Although, the N response in underlying biomass and N transport related characteristics was less than that for biomass, there were clear relationships, most importantly, lines that maintained biomass at reduced N maintained net N uptake with no change in size of the root relative to the shoot. The root uptake capacity for both NO−3 and NH+4 increased with reduced N. Transcript levels of putative NO−3 and NH+4 transporter genes in the root tissue of a subset of the genotypes revealed that predominately ZmNRT2 transcript levels responded to N treatments. The correlation between the ratio of transcripts of ZmNRT2.2 between the two N levels and a genotype's ability to maintain biomass with reduced N suggests a role for these transporters in enhancing NUpE. The observed variation in the ability to capture N at low N provides scope for both improving NUpE in maize and also to better understand the N uptake system in cereals.

  8. Variation for N Uptake System in Maize: Genotypic Response to N Supply

    KAUST Repository

    Garnett, Trevor

    2015-11-09

    An understanding of the adaptations made by plants in their nitrogen (N) uptake systems in response to reduced N supply is important to the development of cereals with enhanced N uptake efficiency (NUpE). Twenty seven diverse genotypes of maize (Zea mays, L.) were grown in hydroponics for 3 weeks with limiting or adequate N supply. Genotypic response to N was assessed on the basis of biomass characteristics and the activities of the nitrate (NO−3) and ammonium (NH+4) high-affinity transport systems. Genotypes differed greatly for the ability to maintain biomass with reduced N. Although, the N response in underlying biomass and N transport related characteristics was less than that for biomass, there were clear relationships, most importantly, lines that maintained biomass at reduced N maintained net N uptake with no change in size of the root relative to the shoot. The root uptake capacity for both NO−3 and NH+4 increased with reduced N. Transcript levels of putative NO−3 and NH+4 transporter genes in the root tissue of a subset of the genotypes revealed that predominately ZmNRT2 transcript levels responded to N treatments. The correlation between the ratio of transcripts of ZmNRT2.2 between the two N levels and a genotype\\'s ability to maintain biomass with reduced N suggests a role for these transporters in enhancing NUpE. The observed variation in the ability to capture N at low N provides scope for both improving NUpE in maize and also to better understand the N uptake system in cereals.

  9. Biofuel, land and water: maize, switchgrass or Miscanthus?

    International Nuclear Information System (INIS)

    Zhuang Qianlai; Qin Zhangcai; Chen Min

    2013-01-01

    The productive cellulosic crops switchgrass and Miscanthus are considered as viable biofuel sources. To meet the 2022 national biofuel target mandate, actions must be taken, e.g., maize cultivation must be intensified and expanded, and other biofuel crops (switchgrass and Miscanthus) must be cultivated. This raises questions on the use efficiencies of land and water; to date, the demand on these resources to meet the national biofuel target has rarely been analyzed. Here, we present a data-model assimilation analysis, assuming that maize, switchgrass and Miscanthus will be grown on currently available croplands in the US. Model simulations suggest that maize can produce 3.0–5.4 kiloliters (kl) of ethanol for every hectare of land, depending on the feedstock to ethanol conversion efficiency; Miscanthus has more than twice the biofuel production capacity relative to maize, and switchgrass is the least productive of the three potential sources of ethanol. To meet the biofuel target, about 26.5 million hectares of land and over 90 km 3 of water (of evapotranspiration) are needed if maize grain alone is used. If Miscanthus was substituted for maize, the process would save half of the land and one third of the water. With more advanced biofuel conversion technology for Miscanthus, only nine million hectares of land and 45 km 3 of water would probably meet the national target. Miscanthus could be a good alternative biofuel crop to maize due to its significantly lower demand for land and water on a per unit of ethanol basis. (letter)

  10. Growth, cadmium uptake and accumulation of maize (Zea mays L.) under the effects of arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Liu, Lingzhi; Gong, Zongqiang; Zhang, Yulong; Li, Peijun

    2014-12-01

    The effects of three arbuscular mycorrhizal fungi isolates on Cd uptake and accumulation by maize (Zea mays L.) were investigated in a planted pot experiment. Plants were inoculated with Glomus intraradices, Glomus constrictum and Glomus mosseae at three different Cd concentrations. The results showed that root colonization increased with Cd addition during a 6-week growth period, however, the fungal density on roots decreased after 9-week growth in the treatments with G. constrictum and G. mosseae isolates. The percentage of mycorrhizal colonization by the three arbuscular mycorrhizal fungi isolates ranged from 22.7 to 72.3%. Arbuscular mycorrhizal fungi inoculations decreased maize biomass especially during the first 6-week growth before Cd addition, and this inhibitory effect was less significant with Cd addition and growth time. Cd concentrations and uptake in maize plants increased with arbuscular mycorrhizal fungi colonization at low Cd concentration (0.02 mM): nonetheless, it decreased at high Cd concentration (0.20 mM) after 6-week growth period. Inoculation with G. constrictum isolates enhanced the root Cd concentrations and uptake, but G. mosseae isolates showed the opposite results at high Cd concentration level after 9 week growth period, as compared to non-mycorrhizal plants. In conclusion, maize plants inoculated with arbuscular mycorrhizal fungi were less sensitive to Cd stress than uninoculated plants. G. constrictum isolates enhanced Cd phytostabilization and G. mosseae isolates reduced Cd uptake in maize (Z. mays L.).

  11. [Effects of soil pH on the competitive uptake of amino acids by maize and microorganisms].

    Science.gov (United States)

    Ma, Qing Xu; Wang, Jun; Cao, Xiao Chuang; Sun, Yan; Sun, Tao; Wu, Liang Huan

    2017-07-18

    Organic nitrogen can play an important role in plant growth, and soil pH changed greatly due to the over-use of chemical fertilizers, but the effects of soil pH on the competitive uptake of amino acids by plants and rhizosphere microorganisms are lack of detailed research. To study the effects of soil pH on the uptake of amino acids by maize and soil microorganisms, two soils from Hangzhou and Tieling were selected, and the soil pH was changed by the electrokinesis, then the 15 N-labeled glycine was injected to the centrifuge tube with a short-term uptake of 4 h. Soil pH had a significant effect on the shoot and root biomass, and the optimal pH for maize shoot growth was 6.48 for Hangzhou red soil, while it was 7.65 for Tieling brown soil. For Hangzhou soil, the 15 N abundance of maize shoots under pH=6.48 was significantly higher than under other treatments, and the uptake amount of 15 N-glycine was also much higher. However, the 15 N abundance of maize shoots and roots under pH=7.65 Tieling soil was significantly lower than it under pH=5.78, but the uptake amount of 15 N-glycine under pH=7.65 was much higher. The microbial biomass C was much higher in pH=6.48 Hangzhou soil, while it was much lower in pH=7.65 Tieling soil. According to the results of root uptake, root to shoot transportation, and the competition with microorganisms, we suggested that although facing the fierce competition with microorganisms, the maize grown in pH=6.48 Hangzhou soil increased the uptake of glycine by increasing its root uptake and root to shoot transportation. While in pH=7.65 Tieling soil, the activity of microorganisms was decreased, which decreased the competition with maize for glycine, and increased the uptake of glycine by maize.

  12. Phosphorus-loaded biochar changes soil heavy metals availability and uptake potential of maize (Zea mays L.) plants.

    Science.gov (United States)

    Ahmad, Munir; Usman, Adel R A; Al-Faraj, Abdullah S; Ahmad, Mahtab; Sallam, Abdelazeem; Al-Wabel, Mohammad I

    2018-03-01

    Biochar (BC) was produced by pyrolyzing the date palm leaf waste at 600 °C and then loaded with phosphorus (P) via sorption process. Greenhouse pot experiment was conducted to investigate the application effects of BC and P-loaded biochar (BCP) on growth and availability of P and heavy metals to maize (Zea mays L.) plants grown in contaminated mining soil. The treatments consisted of BC and BCP (at application rates of 5, 10, 20, and 30 g kg -1 of soil), recommended NK and NPK, and a control (no amendment). Sorption experiment showed that Langmuir predicted maximum P sorption capacity of BC was 13.71 mg g -1 . Applying BCP increased the soil available P, while BC and BCP significantly decreased the soil labile heavy metals compared to control. Likewise, heavy metals in exchangeable and reducible fractions were transformed to more stable fraction with BC and BCP applications. The highest application rate of BCP (3%) was most effective treatment in enhancing plant growth parameters (shoot and root lengths and dry matter) and uptake of P and heavy metals by 2-3 folds. However, based on metal uptake and phytoextraction indices, total heavy metals extraction by maize plants was very small for practical application. It could be concluded that using P-loaded biochar as a soil additive may be considered a promising tool to immobilize heavy metals in contaminated mining areas, while positive effects on the biomass growth of plants may assist the stabilization of contaminated areas affected by wind and water erosion. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Relation of zinc levels and water soluble phosphorus in suphala [fertilizer] on uptake of phosphorus and zinc

    International Nuclear Information System (INIS)

    Mutatkar, V.K.; Chapke, V.G.

    1975-01-01

    Under pot culture, four levels of Zn 0, 2, 4 and 6 ppm, were studied in relation to 30, 50 and 100 % water soluble levels of phosphorus in suphala for the dry matter production and uptake of P and Zn by maize on acidic soil of Goa and black cotton soil of Maharashtra. 32 P and 65 Zn tracers were used for this investigation. The results revealed that application of Zn has increased the dry matter and uptake of phosphorus upto 4 ppm of Zn application and it has decreased at 6 ppm Zn level. This inhibition of P uptake was observed at all water soluble levels of P and in both the soils studied. Zn uptake by maize in both the soils under study was increased with increasing level of Zn, irrespective of water soluble level of P in suphala. (author)

  14. Study on the effect of x-ray irradiation of seed on zinc uptake in maize (Zea Mays L.) plants

    International Nuclear Information System (INIS)

    Joshi, Gargi; Singh, K.P.; Joshi, G.C.

    2007-01-01

    The effects of irradiations by X-rays at the two dose levels (1.1 KR and 2.2 KR) of seeds on uptake of zinc ion in maize (Zea Mays L.) plants were studied. The uptake and internal distribution of zinc ion in the maize plants was carried out by incorporating radioactive zinc as zinc chloride (ZnCl 2 ) in the nutrient solution to the plants. The localization and translocation of radioactive zinc was studied employing phosphor imaging systems (FX). The radioactivity measurement has been carried out using solid scintillation counter. It was observed that zinc ions uptake was higher in plants out of 2.2 KR X-rays irradiated seeds. (author)

  15. The effect and fate of water-soluble carbon nanodots in maize (Zea mays L.).

    Science.gov (United States)

    Chen, Jing; Dou, Runzhi; Yang, Zhongzhou; Wang, Xiaoping; Mao, Chuanbin; Gao, Xiang; Wang, Li

    2016-08-01

    In this study, the toxicity of water-soluble carbon nanodots (C-dots) to maize (Zea mays L.) and their uptake and transport in plants were investigated. After exposed in sand matrix amended with 0-2000 mg/L C-dots for 4 weeks, we found that the phytotoxicity of C-dots was concentration-dependent. C-dots at 250 and 500 mg/L showed no toxicity to maize. However, 1000 and 2000 mg/L C-dots significantly reduced the fresh weight of root by 57% and 68%, and decreased the shoot fresh weight by 38% and 72%, respectively. Moreover, in maize roots, the exposure of C-dots at 2000 mg/L significantly increased the H2O2 content and lipid peroxidation (6.5 and 1.65 times higher, respectively), as well as, the antioxidant enzymes activities, up to 2, 1.5, 1.9 and 1.9 times higher for catalase, ascorbate peroxidase, guaiacol peroxidase and superoxide dismutase, respectively. On the other hand, C-dots were observed in detached root-cap cells, cortex and vascular bundle of roots and mesophyll cells of leaves through fluorescence microscopy analysis, suggesting that C-dots were absorbed and translocated systemically in maize. Remarkably, a certain amount of C-dots were excreted out from leaf blade. To our knowledge, this is the first study combined phenotypic observation with physiologic responses and bioaccumulation and translocation analysis of C-dots to investigate their effect and fate in maize.

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

    Science.gov (United States)

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

    2017-08-01

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

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

    Directory of Open Access Journals (Sweden)

    Q. Cai

    2017-08-01

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

  18. The water footprint of sweeteners and bio-ethanol from sugar cane, sugar beet and maize

    NARCIS (Netherlands)

    Gerbens-Leenes, Winnie; Hoekstra, Arjen Ysbert

    2009-01-01

    Sugar cane and sugar beet are used for sugar for human consumption. In the US, maize is used, amongst others, for the sweetener High Fructose Maize Syrup (HFMS). Sugar cane, sugar beet and maize are also important for bio-ethanol production. The growth of crops requires water, a scarce resource. The

  19. Effects of zinc complexes on the distribution of zinc in calcareous soil and zinc uptake by maize.

    Science.gov (United States)

    Alvarez, José M; Rico, María I

    2003-09-10

    The movement and availability of Zn from six organic Zn sources in a Typic Xerorthent (calcareous) soil were compared by incubation, column assay, and in a greenhouse study with maize (Zea mays L.). Zinc soil behavior was studied by sequential, diethylenetriaminepentaacetate, and Mehlich-3 extractions. In the incubation experiment, the differences in Zn concentration observed in the water soluble plus exchangeable fraction strongly correlated with Zn uptake by plants in the greenhouse experiment. Zinc applied to the surface of soil columns scarcely moved into deeper layers except for Zn-ethylenediaminetetraacetate (EDTA) that showed the greatest distribution of labile Zn throughout the soil and the highest proportion of leaching of the applied Zn. In the upper part of the column, changes in the chemical forms of all treatments occurred and an increase in organically complexed and amorphous Fe oxide-bound fractions was detected. However, the water soluble plus exchangeable fraction was not detected. The same results were obtained at the end of the greenhouse experiment. Significant increases were found in plant dry matter yield and Zn concentration as compared with the control treatment without Zn addition. Increasing Zn rate in the soil increased dry matter yield in all cases but Zn concentration in the plant increased only with Zn-EDTA and Zn-ethylenediaminedi-o-hydroxyphenyl-acetate (EDDHA) fertilizers. Higher Zn concentration in plants (50.9 mg kg(-)(1)) occurred when 20 mg Zn kg(-)(1) was added to the soil as Zn-EDTA. The relative effectiveness of the different Zn carriers in increasing Zn uptake was in the order: Zn-EDTA > Zn-EDDHA > Zn-heptagluconate >/= Zn-phenolate approximately Zn-polyflavonoid approximately Zn-lignosulfonate.

  20. Inferring foliar water uptake using stable isotopes of water.

    Science.gov (United States)

    Goldsmith, Gregory R; Lehmann, Marco M; Cernusak, Lucas A; Arend, Matthias; Siegwolf, Rolf T W

    2017-08-01

    A growing number of studies have described the direct absorption of water into leaves, a phenomenon known as foliar water uptake. The resultant increase in the amount of water in the leaf can be important for plant function. Exposing leaves to isotopically enriched or depleted water sources has become a common method for establishing whether or not a plant is capable of carrying out foliar water uptake. However, a careful inspection of our understanding of the fluxes of water isotopes between leaves and the atmosphere under high humidity conditions shows that there can clearly be isotopic exchange between the two pools even in the absence of a change in the mass of water in the leaf. We provide experimental evidence that while leaf water isotope ratios may change following exposure to a fog event using water with a depleted oxygen isotope ratio, leaf mass only changes when leaves are experiencing a water deficit that creates a driving gradient for the uptake of water by the leaf. Studies that rely on stable isotopes of water as a means of studying plant water use, particularly with respect to foliar water uptake, must consider the effects of these isotopic exchange processes.

  1. Modelling water uptake efficiency of root systems

    Science.gov (United States)

    Leitner, Daniel; Tron, Stefania; Schröder, Natalie; Bodner, Gernot; Javaux, Mathieu; Vanderborght, Jan; Vereecken, Harry; Schnepf, Andrea

    2016-04-01

    Water uptake is crucial for plant productivity. Trait based breeding for more water efficient crops will enable a sustainable agricultural management under specific pedoclimatic conditions, and can increase drought resistance of plants. Mathematical modelling can be used to find suitable root system traits for better water uptake efficiency defined as amount of water taken up per unit of root biomass. This approach requires large simulation times and large number of simulation runs, since we test different root systems under different pedoclimatic conditions. In this work, we model water movement by the 1-dimensional Richards equation with the soil hydraulic properties described according to the van Genuchten model. Climatic conditions serve as the upper boundary condition. The root system grows during the simulation period and water uptake is calculated via a sink term (after Tron et al. 2015). The goal of this work is to compare different free software tools based on different numerical schemes to solve the model. We compare implementations using DUMUX (based on finite volumes), Hydrus 1D (based on finite elements), and a Matlab implementation of Van Dam, J. C., & Feddes 2000 (based on finite differences). We analyse the methods for accuracy, speed and flexibility. Using this model case study, we can clearly show the impact of various root system traits on water uptake efficiency. Furthermore, we can quantify frequent simplifications that are introduced in the modelling step like considering a static root system instead of a growing one, or considering a sink term based on root density instead of considering the full root hydraulic model (Javaux et al. 2008). References Tron, S., Bodner, G., Laio, F., Ridolfi, L., & Leitner, D. (2015). Can diversity in root architecture explain plant water use efficiency? A modeling study. Ecological modelling, 312, 200-210. Van Dam, J. C., & Feddes, R. A. (2000). Numerical simulation of infiltration, evaporation and shallow

  2. Effect of incorporation of 32P labelled green manure (Sesbania aculeata) on the yield ans P uptake by maize

    International Nuclear Information System (INIS)

    Vig, A.C.; Singh, Didar; Biswas, C.R.; Chand, Milap

    1989-01-01

    The effect of applied inorganic P and 32 P labelled Sesbania aculeata (dhaincha) as green manure on the yield and P utilization by maize (Zea mays L.) in soils of two long term experiments was studied in a greenhouse experiment. Significant increase in the drymatter yield and total P uptake was obtained with increasing level of applied sesbania and P fertilizer. The relationship between total P uptake and total P added as organic plus inorganic fertilizer was significant. The Sesbania application significantly increased per cent P derived from added plant material by the maize crop. It also enhanced P uptake and its utilization from fertilizer source. The addition of Sesbania in the absence and presence of inorganic P fertilizer improved P use efficiency. The direct beneficial effect of added organic P was significant only in its application on soils with lower level of residual P. The utilization of P by maize after addition of sesbania varied from 5 to 9 per cent. (author). 10 refs., 3 tabs

  3. Impacts of industrial waste resources on maize (Zea mays L.) growth, yield, nutrients uptake and soil properties.

    Science.gov (United States)

    Singh, Satnam; Young, Li-Sen; Shen, Fo-Ting; Young, Chiu-Chung

    2014-10-01

    Discharging untreated highly acidic (pH10.0) paper-mill wastewater (PW) causes environmental pollution. When acidity of MW neutralized (pH 6.5±0.1) with PW and lime (treatments represented as MW+PW and MW+Lime), then MW may be utilized as a potential source of nutrients and organic carbon for sustainable food production. Objectives of this study were to compare the effects of PW and lime neutralized MW and chemical fertilizers on maize (Zea mays L. cv. Snow Jean) plant growth, yield, nutrients uptake, soil organic matter and humic substances. The field experiment was carried out on maize using MW at 6000 L ha(-1). Impacts of the MW application on maize crop and soil properties were evaluated at different stages. At harvest, plant height, and plant N and K uptake were higher in MW treatment. Leaf area index at 60 days after sowing, plant dry matter accumulation at harvest, and kernels ear(-1) and 100-kernel weight were higher in MW+Lime treatment. Kernel N, P, K, Mn, Fe and Zn, and plant Zn uptake were highest in MW+Lime. Plant Fe uptake, and soil organic matter and humic substances were highest in MW+PW. The MW+PW and MW+Lime treatments exhibited comparable results with chemically fertilized treatment. The MW acidity neutralized with lime showed positive impacts on growth, yield and nutrients uptake; nevertheless, when MW pH neutralized with PW has an additional benefit on increase in soil organic matter and humic substances. Copyright © 2014. Published by Elsevier Ltd.

  4. Analysis of water and nitrogen use efficiency for maize (Zea mays L.) grown on soft rock and sand compound soil.

    Science.gov (United States)

    Wang, Huanyuan; Han, Jichang; Tong, Wei; Cheng, Jie; Zhang, Haiou

    2017-06-01

    Maize was grown on compound soils constituted from mixtures of soft rock and sand at different ratios, and water use efficiency (WUE), nitrogen use efficiency (NUE) and fertilizer nitrogen use efficiency (FNUE) were quantified. The data were used to assist in designing strategies for optimizing water and nitrogen management practices for maize on the substrates used. Maize was sown in composite soil prepared at three ratios of soft rock and sand (1:1, 1:2 and 1:5 v/v) in Mu Us Sandy Land, Yuyang district, Yulin city, China. Yields, amount of drainage, nitrogen (N) leaching, WUE and NUE were calculated. Then a water and nitrogen management model (WNMM) was calibrated and validated. No significant difference in evapotranspiration of maize was found among compound soils with soft rock/sand ratios of 1:1, 1:2 and 1:5, while water drainage increased significantly with increasing soft rock/sand ratio. WUE increased to 1.30 kg m -3 in compound soil with 1:2 soft rock/sand ratio. Nitrogen leaching and ammonia volatilization were the main reason for nitrogen loss, and N reduction mainly relied on crop uptake. NUE and FNUE could reach 33.1 and 24.9 kg kg -1 N respectively. Water drainage and nitrogen leaching occurred mostly during heavy rainfall or irrigation. Through a scenario analysis of different rainfall types, water and fertilizer management systems were formulated each year. This study shows that soft rock plays a key role in improving the WUE, NUE and FNUE of maize. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  5. Soil Fertility Status, Nutrient Uptake, and Maize (Zea mays L.) Yield Following Organic Matters and P Fertilizer Application on Andisol

    Science.gov (United States)

    Minardi, S.; Harieni, S.; Anasrullah, A.; Purwanto, H.

    2017-04-01

    Objective of this study were to elucidate effects of organic matters and P fertilizer application on soil fertility status, nutrient uptake and maize yield in the Andisol. This experiment consisted of two factors. The first factor comprised of four levels of organic matters input (without organic matter, manure, rice straw, and Gliricidia sepium leaves), with the application dosage 10 t.ha-1 and the second factor comprised of three levels of P fertilizer application (without P addition (control), 50 kg P2O5 ha-1, 100 kg P2O5 ha-1). Results of this study showed that organic matters and P fertilizer application improved soil fertility status, especially pH, soil organic C, cation exchange capacity (CEC), available P which resulted in an increase in P uptake that improve yield of maize. The highest yield of maize (corn cob) was obtained through application Gliricida sepium (8.40 t.ha-1), followed by manure (6.02 t.ha-1) and rice straw (5.87 t.ha-1). Application of 50 kg P2O5 Ha-1 yield was (5.76 t.ha-1) and application of 100 Kg P2O5 Ha-1 yield was (6.12 t.ha-1).

  6. 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)

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

    Science.gov (United States)

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

    2007-10-15

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

  8. Incorporating a water-logging routine into CERES-Maize, and some ...

    African Journals Online (AJOL)

    The inability of CERES-Maize v3.0 to simulate a fluctuating water table has been identified as a major constraint in using this particular model in South Africa and in Kenya. Information regarding fluctuating water tables under specific conditions, and their influence on maize production, has been presented in South African ...

  9. Plant uptake of dual-labeled organic N biased by inorganic C uptake

    DEFF Research Database (Denmark)

    Rasmussen, Jim; Sauheitl, Leopold; Eriksen, Jørgen

    2010-01-01

    glycine or CO2-3 , but found no differences in uptake rates between these C-sources. The uptake of inorganic C to the shoot tissue was higher for maize grown in full light compared to shading, which indicates a passive uptake of inorganic C with water. We conclude that uptake of inorganic C produced...

  10. Relative efficiency of different methods of phosphorus (32P) application on fertilizer phosphorus uptake by maize (zea may L.)

    International Nuclear Information System (INIS)

    Chaudhary, M.L.; Gupta, A.P.

    1975-01-01

    A green house study was conducted for comparing four methods of phosphorus application (broad cast, below the seed, one side and both sides of the seeds) at the rate of 60 ppm in sierozem soil of H issar (Haryana). Maize crop was planted in 50 cm. bottomless bitumin drums for 70 days i.e. upto tasseling stage. The plant samples were collected at jointing and tasseling stages of plant growth. The results revealed that the highest dry matter yield, total and fertilizer phosphorus uptake was observed when the phosphorus was applied below the seed, followed by both side application of phosphorus. The least yield, total and fertilizer phosphorus uptake were recorded when the phosphorus was broadcast at the time of sowing. (author)

  11. Spatiotemporal variation of nitrate uptake kinetics within the maize (Zea mays L.) root system is associated with greater nitrate uptake and interactions with architectural phenes.

    Science.gov (United States)

    York, Larry M; Silberbush, Moshe; Lynch, Jonathan P

    2016-06-01

    Increasing maize nitrogen acquisition efficiency is a major goal for the 21st century. Nitrate uptake kinetics (NUK) are defined by I max and K m, which denote the maximum uptake rate and the affinity of transporters, respectively. Because NUK have been studied predominantly at the molecular and whole-root system levels, little is known about the functional importance of NUK variation within root systems. A novel method was created to measure NUK of root segments that demonstrated variation in NUK among root classes (seminal, lateral, crown, and brace). I max varied among root class, plant age, and nitrate deprivation combinations, but was most affected by plant age, which increased I max, and nitrate deprivation time, which decreased I max K m was greatest for crown roots. The functional-structural simulation SimRoot was used for sensitivity analysis of plant growth to root segment I max and K m, as well as to test interactions of I max with root system architectural phenes. Simulated plant growth was more sensitive to I max than K m, and reached an asymptote near the maximum I max observed in the empirical studies. Increasing the I max of lateral roots had the largest effect on shoot growth. Additive effects of I max and architectural phenes on nitrate uptake were observed. Empirically, only lateral root tips aged 20 d operated at the maximum I max, and simulations demonstrated that increasing all seminal and lateral classes to this maximum rate could increase plant growth by as much as 26%. Therefore, optimizing I max for all maize root classes merits attention as a promising breeding goal. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  12. Amendment of Tephrosia Improved Fallows with Inorganic Fertilizers Improves Soil Chemical Properties, N Uptake, and Maize Yield in Malawi

    Directory of Open Access Journals (Sweden)

    Maggie G. Munthali

    2014-01-01

    Full Text Available Maize production in Malawi is limited mainly by low soil N and P. Improved fallows of N-fixing legumes such as Tephrosia and Sesbania offer options for improving soil fertility particularly N supply. The interactions of Tephrosia fallows and inorganic fertilizers on soil properties, N uptake, and maize yields were evaluated at Chitedze Research Station in Malawi. The results indicated that the level of organic matter and pH increased in all the treatments except for the control. Total N remained almost unchanged while available P decreased in all plots amended with T. vogelii but increased in T. candida plots where inorganic P was applied. Exchangeable K increased in all the plots irrespective of the type of amendment. The interaction of N and P fertilizers with T. vogelii fallows significantly increased the grain yield. The treatment that received 45 kg N ha−1 and 20 kg P ha−1 produced significantly higher grain yields (6.8 t ha−1 than all the other treatments except where 68 kg N ha−1 and 30 kg P ha−1 were applied which gave 6.5 t ha−1 of maize grain. T. candida fallows alone or in combination with N and P fertilizers did not significantly affect grain yield. However, T. candida fallows alone can raise maize grain yield by 300% over the no-input control. Based on these results we conclude that high quality residues such as T. candida and T. vogelii can be used as sources of nutrients to improve crop yields and soil fertility in N-limited soils. However, inorganic P fertilizer is needed due to the low soil available P levels.

  13. The effect of Zn, N and P application on nutrient uptake in wheat-maize sequence using isotopic techniques

    International Nuclear Information System (INIS)

    Tehrani, M.M.; Sachdev, P.; Sachdev, M.S.

    2006-01-01

    A pot experiment was conducted at the Nuclear Research Laboratory , Indian Agricultural Research Institute, New Delhi in 2000-2001. The experiment was 3x3x3 factorial in Completely Randomized Design (CRD) with three replications. Fertilizers were applied as three levels of zinc 0. 2.5 and 5 mg Zn kg -1 as ZnSO 4 , three levels of phosphorus 0, 7.5 and 15 mg P kg -1 through KH 2 PO 4 and three levels of nitrogen 30, 60 and 90 mg N kg -1 as urea. Zn fertilizer was not applied for the second crop in sequence. The amount of available Zn in soil decreased by the application of P and N, but increased by the Zn application. The P application increased the available pool of P in soil, but the zinc levels had no effect on it. Data revealed that the P application decreased the Zn concentration in plant tissue for both the crops. The per cent N utilization decreased drastically with increasing rate of N application from N 30 to N 90 in wheat. The highest level of P application resulted in least total Zn uptake, per cent Zndff, fertilizer Zn uptake and per cent Zn utilized from fertilizer. The no zinc application showed the highest value of Zn application to the wheat crop. The highest values of total P uptake, per cent Pdff, fertilizer uptake and per cent P utilized from fertilizer in the succeeding crop of maize were observed with residual effect of Zn 5 among three levels of Zn application to the first crop of maize. (author)

  14. Effect of zinc and phosphorus on dry matter yield, uptake and utilization of 65Zn on Maize (Zea Mays L.) grown in a molli-soil

    International Nuclear Information System (INIS)

    Joshi, Megha; Shri Ram; Joshi, G.C.

    2013-01-01

    Zinc uptake and its utilization by Maize (Zea mays L.) variety Pragati using radiotracer 65 Zn technique along with varying levels of phosphorus treatments on dry matter yield was studied. The gamma activity was measured by calibrated NaI(Tl) gamma ray spectrometer. It was observed that zinc uptake in treatment T 2 found to be higher. However, treatment T 6 showed good growth parameters and dry matter yield. The 65 Zn activity was found maximum in roots and minimum in the leaves of maize plant. (author)

  15. Spatial pattern characteristics of water footprint for maize production in Northeast China.

    Science.gov (United States)

    Duan, Peili; Qin, Lijie; Wang, Yeqiao; He, Hongshi

    2016-01-30

    Water footprint (WF) methodology is essential for quantifying total water consumption of crop production and making efficient water management policies. This study calculated the green, blue, grey and total WFs of maize production in Northeast China from 1998 to 2012 and compared the values of the provinces. This study also analyzed the spatial variation and structure characteristics of the WFs at the prefecture level. The annual average WF of maize production was 1029 m(3) per ton, which was 51% green, 21% blue and 28% grey. The WF of maize production was highest in Liaoning Province, moderate in Heilongjiang Province and lowest in Jilin Province. The spatial differences of the WFs calculated for the 36 major maize production prefectures were significant in Northeast China. There was a moderate positive spatial autocorrelation among prefectures that had similar WFs. Local indicator of spatial autocorrelation index (LISA) analysis identified prefectures with higher WFs in the southeast region of Liaoning Province and the southwest region of Heilongjiang Province and prefectures with lower WFs in the middle of Jilin Province. Spatial differences in the WF of maize production were caused mainly by variations in climate conditions, soil quality, irrigation facilities and maize yield. The spatial distribution of WFs can help provide a scientific basis for optimizing maize production distribution and then formulate strategies to reduce the WF of maize production. © 2015 Society of Chemical Industry.

  16. Molecular mechanisms of foliar water uptake in a desert tree

    OpenAIRE

    Yan, Xia; Zhou, Maoxian; Dong, Xicun; Zou, Songbing; Xiao, Honglang; Ma, Xiao-Fei

    2015-01-01

    Water deficits severely affect growth, particularly for the plants in arid and semiarid regions of the world. In addition to precipitation, other subsidiary water, such as dew, fog, clouds and small rain showers, may also be absorbed by leaves in a process known as foliar water uptake. With the severe scarcity of water in desert regions, this process is increasingly becoming a necessity. Studies have reported on physical and physiological processes of foliar water uptake. However, the molecul...

  17. 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

  18. Yield and water use efficiency of deficit-irrigated maize in a semi ...

    African Journals Online (AJOL)

    Yield and water use efficiency of deficit-irrigated maize in a semi-arid region of Ethiopia. ... PROMOTING ACCESS TO AFRICAN RESEARCH. AFRICAN JOURNALS ONLINE ... African Journal of Food, Agriculture, Nutrition and Development.

  19. Mycorrhizal phosphate uptake pathway in maize: Vital for growth and cob development on nutrient poor agricultural and greenhouse soils

    Directory of Open Access Journals (Sweden)

    Martin eWillmann

    2013-12-01

    Full Text Available Arbuscular mycorrhizal fungi (AMF form a mutually beneficial symbiosis with plant roots providing predominantly phosphorus in the form of orthophosphate (Pi in exchange for plant carbohydrates on low P soils. The goal of this work was to generate molecular-genetic evidence in support of a major impact of the mycorrhizal Pi uptake (MPU pathway on the productivity of the major crop plant maize under field and controlled conditions. Here we show, that a loss-of-function mutation in the mycorrhiza-specific Pi transporter gene Pht1;6 correlates with a dramatic reduction of above-ground biomass and cob production in agro-ecosystems with low P soils. In parallel mutant pht1;6 plants exhibited an altered fingerprint of chemical elements in shoots dependent on soil P availability. In controlled environments mycorrhiza development was impaired in mutant plants when grown alone. The presence of neighbouring mycorrhizal nurse plants enhanced the reduced mycorrhiza formation in pht1;6 roots. Uptake of 33P-labelled orthophosphate via the MPU pathway was strongly impaired in colonized mutant plants. Moreover, repression of the MPU pathway resulted in a redirection of Pi to neighbouring plants. In line with previous results, our data highlight the relevance of the MPU pathway in Pi allocation within plant communities and in particular the role of Pht1;6 for the establishment of symbiotic Pi uptake and for maize productivity and nutritional value in low-input agricultural systems. In a first attempt to identify cellular pathways which are affected by Pht1;6 activity, gene expression profiling via RNA-Seq was performed and revealed a set of maize genes involved in cellular signalling which exhibited differential regulation in mycorrhizal pht1;6 and control plants. The RNA data provided support for the hypothesis that fungal supply of Pi and/or Pi transport across Pht1;6 affects cell wall biosynthesis and hormone metabolism in colonized root cells.

  20. Effects of No-tillage Combined with Reused Plastic Film Mulching on Maize Yield and Irrigation Water Productivity

    Directory of Open Access Journals (Sweden)

    SU Yong-zhong

    2016-09-01

    Full Text Available A field experiment was conducted to determine the effects of reused plastic film mulching and no-tillage on maize yield and irriga-tion water productivity(IWP in the marginal oasis in the middle of Hexi Corridor region of northwestern China. The aim is to provide an alternative tillage and cultivation pattern for reducing plastic film pollution, saving cost and increasing income, and improving resource use efficiency. The field experiment was carried out in three soils with different textures and fertility levels. Three treatments for each soil were set up:(1 conventional tillage,winter irrigation, and new plastic mulching cultivation(NM;(2 no tillage, less winter irrigation and reused plastic mulching cultivation (RM;(3 no tillage, less winter irrigation and reused plastic mulching combined with straw mulching (RMS. The results showed that the average daily soil temperature in the two reused plastic mulching treatment(RM and RMS during maize sowing and elongation stage was lower 0.6~1.0℃(5 cm depth and 0.5~0.8℃(15 cm depth than that in the NM. This result suggested that no tillage and reused plastic mulching cultivation still had the effect of increasing soil temperature. Maize grain yield in the RM was reduced by 4.4%~10.6% compared with the conventional cultivation(NM, while the net income increased due to saving in plastic film and tillage ex-penses. There was no significant difference in maize grain yield between the RMS and NM treatment, but the net income in the RMS was in-creased by 12.5%~17.1% than that in the NM. Compared with the NM, the two reused plastic film mulching treatments (RM and RMS decreased the volume of winter irrigation, but maize IWP increased. Soil texture and fertility level affected significantly maize nitrogen uptake and IWP. In the arid oases with the shortage of water resources, cultivation practices of conservation tillage with recycle of plastic film is an ideal option for saving cost and increasing income

  1. Effect of phosphorus and zinc on growth and their uptake in hybrid maize grown in a calcareous alluvial soil

    International Nuclear Information System (INIS)

    Parik, B.L.; Santikari, A.K.; Das, S.K.; Chowdhury, B.

    1977-01-01

    Hybrid maize (Zea mays L., var. Ganga 101) was grown in glasshouse at different levels of phosphorus with and without zinc, in a calcareous alluvial soil of North Bihar. Phosphorus was applied at 0, 11, 22, 44 and 88 ppm as tagged P in single superphosphats. Zinc was applied at 0 and 10 ppm as 65 ZnCl 2 . Application of phosphorus and zinc significantly increased the dry matter yield up to P 44 . Higher dose of P resulted in depressed growth accompanied by decreased zinc concentration and uptake by plants, exhibiting zinc deficiency symptoms. Higher levels of P and Zn increased their concentrations in the plant, but their total uptake was reduced at P 88 . With higher levels of P the percent utilization of fertilizer P decreased, while in zinc treated soils uptake of fertilizer P increased. Percent utilization of added zinc increased with increase in P levels upto P 44 and decreased thereafter, although at this level of P a greater percentage of zinc was derived from the fertilizer. (author)

  2. 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)

  3. Tillage methods and mulch on water saving and yield of spring maize in Chitwan

    Directory of Open Access Journals (Sweden)

    Ishwari Prasad Upadhyay

    2016-12-01

    Full Text Available Tillage methods and mulch influences the productivity and water requirement of spring maize hence a field experiment was conducted at the National Maize Research Program, Rampur in spring seasons of 2011 and 2012 with the objectives to evaluate different tillage methods with and without mulch on water requirement and grain yield of spring maize. The experiment was laid out in two factors factorial randomized complete design with three replications. The treatments consisted of tillage methods (Permanent bed, Zero tillage and Conventional tillage and mulch (with and without. Irrigation timing was fixed as knee high stage, tasseling stage and milking/dough stage. Data on number of plants, number of ears, thousand grain weight and grain yield were recorded and analysed using GenStat. Two years combined result showed that the effect of tillage methods and mulch significant influenced grain yield and water requirement of spring maize. The maize grain yield was the highest in permanent beds with mulch (4626 kg ha-1 followed by zero tillage with mulch (3838 kg ha-1. Whereas total water applied calculated during the crop period were the highest in conventional tillage without mulch followed by conventional tillage with mulch. The permanent bed with mulch increased the yield and reduced the water requirement of spring maize in Chitwan.

  4. Molecular mechanisms of foliar water uptake in a desert tree.

    Science.gov (United States)

    Yan, Xia; Zhou, Maoxian; Dong, Xicun; Zou, Songbing; Xiao, Honglang; Ma, Xiao-Fei

    2015-11-12

    Water deficits severely affect growth, particularly for the plants in arid and semiarid regions of the world. In addition to precipitation, other subsidiary water, such as dew, fog, clouds and small rain showers, may also be absorbed by leaves in a process known as foliar water uptake. With the severe scarcity of water in desert regions, this process is increasingly becoming a necessity. Studies have reported on physical and physiological processes of foliar water uptake. However, the molecular mechanisms remain less understood. As major channels for water regulation and transport, aquaporins (AQPs) are involved in this process. However, due to the regulatory complexity and functional diversity of AQPs, their molecular mechanism for foliar water uptake remains unclear. In this study, Tamarix ramosissima, a tree species widely distributed in desert regions, was investigated for gene expression patterns of AQPs and for sap flow velocity. Our results suggest that the foliar water uptake of T. ramosissima occurs in natural fields at night when the humidity is over a threshold of 85 %. The diurnal gene expression pattern of AQPs suggests that most AQP gene expressions display a circadian rhythm, and this could affect both photosynthesis and transpiration. At night, the PIP2-1 gene is also upregulated with increased relative air humidity. This gene expression pattern may allow desert plants to regulate foliar water uptake to adapt to extreme drought. This study suggests a molecular basis of foliar water uptake in desert plants. Published by Oxford University Press on behalf of the Annals of Botany Company.

  5. Quantifying potential yield and water-limited yield of summer maize in the North China Plain

    Science.gov (United States)

    Jiang, Mingnuo; Liu, Chaoshun; Chen, Maosi

    2017-09-01

    The North China Plain is a major food producing region in China, and climate change could pose a threat to food production in the region. Based on China Meteorological Forcing Dataset, simulating the growth of summer maize in North China Plain from 1979 to 2015 with the regional implementation of crop growth model WOFOST. The results showed that the model can reflect the potential yield and water-limited yield of Summer Maize in North China Plain through the calibration and validation of WOFOST model. After the regional implementation of model, combined with the reanalysis data, the model can better reproduce the regional history of summer maize yield in the North China Plain. The yield gap in Southeastern Beijing, southern Tianjin, southern Hebei province, Northwestern Shandong province is significant, these means the water condition is the main factor to summer maize yield in these regions.

  6. Role of microbial inoculation and industrial by-product phosphogypsum in growth and nutrient uptake of maize (Zea mays L.) grown in calcareous soil.

    Science.gov (United States)

    Al-Enazy, Abdul-Aziz R; Al-Oud, Saud S; Al-Barakah, Fahad N; Usman, Adel Ra

    2017-08-01

    Alkaline soils with high calcium carbonate and low organic matter are deficient in plant nutrient availability. Use of organic and bio-fertilizers has been suggested to improve their properties. Therefore, a greenhouse experiment was conducted to evaluate the integrative role of phosphogypsum (PG; added at 0.0, 10, 30, and 50 g PG kg -1 ), cow manure (CM; added at 50 g kg -1 ) and mixed microbial inoculation (Incl.; Azotobacter chroococcum, and phosphate-solubilizing bacteria Bacillus megaterium var. phosphaticum and Pseudomonas fluorescens) on growth and nutrients (N, P, K, Fe, Mn, Zn and Cu) uptake of maize (Zea mays L.) in calcareous soil. Treatment effects on soil chemical and biological properties and the Cd and Pb availability to maize plants were also investigated. Applying PG decreased soil pH. The soil available P increased when soil was inoculated and/or treated with CM, especially with PG. The total microbial count and dehydrogenase activity were enhanced with PG+CM+Incl. Inoculated soils treated with PG showed significant increases in NPK uptake and maize plant growth. However, the most investigated treatments showed significant decreases in shoot micronutrients. Cd and Pb were not detected in maize shoots. Applying PG with microbial inoculation improved macronutrient uptake and plant growth. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  7. Comparative short-term effects of sewage sludge and its biochar on soil properties, maize growth and uptake of nutrients on a tropical clay soil in Zimbabwe

    Institute of Scientific and Technical Information of China (English)

    Willis Gwenzi; Moreblessing Muzava; Farai Mapanda; Tonny P Tauro

    2016-01-01

    Soil application of biochar from sewage could potentialy enhance carbon sequestration and close urban nutrient balances. In sub-Saharan Africa, comparative studies investigating plant growth effect and nutrients uptake on tropical soils amended with sewage sludge and its biochar are very limited. A pot experiment was conducted to investigate the effects of sewage sludge and its biochar on soil chemical properties, maize nutrient and heavy metal uptake, growth and biomass partitioning on a tropical clayey soil. The study compared three organic amendments; sewage sludge (SS), sludge biochar (SB) and their combination (SS+SB) to the unamended control and inorganic fertilizers. Organic amendments were applied at a rate of 15 t ha–1 for SS and SB, and 7.5 t ha–1 each for SS and SB. Maize growth, biomass production and nutrient uptake were signiifcantly improved in biochar and sewage sludge amendments compared to the unamended control. Comparable results were observed with F, SS and SS+SB on maize growth at 49 d of sowing. Maize growth for SB, SS, SS+SB and F increased by 42, 53, 47, and 49%, respectively compared to the unamended control. Total biomass for SB, SS, SS+SB, and F increased by 270, 428, 329, and 429%, respectively compared with the unamended control. Biochar amendments reduced Pb, Cu and Zn uptakes by about 22% compared with sludge alone treatment in maize plants. However, there is need for future research based on the current pot experiment to determine whether the same results can be produced under ifeld conditions.

  8. Estimating plant root water uptake using a neural network approach

    DEFF Research Database (Denmark)

    Qiao, D M; Shi, H B; Pang, H B

    2010-01-01

    but has not yet been addressed. This paper presents and tests such an approach. The method is based on a neural network model, estimating the water uptake using different types of data that are easy to measure in the field. Sunflower grown in a sandy loam subjected to water stress and salinity was taken......Water uptake by plant roots is an important process in the hydrological cycle, not only for plant growth but also for the role it plays in shaping microbial community and bringing in physical and biochemical changes to soils. The ability of roots to extract water is determined by combined soil...... and plant characteristics, and how to model it has been of interest for many years. Most macroscopic models for water uptake operate at soil profile scale under the assumption that the uptake rate depends on root density and soil moisture. Whilst proved appropriate, these models need spatio-temporal root...

  9. Influence of growing measures on weed interference and water status in maize

    Directory of Open Access Journals (Sweden)

    Simić Milena

    2017-01-01

    Full Text Available Growing modern hybrids in narrow plant spacing together with nitrogen and herbicide application gives an advantage to maize crops over weeds. The aim of the present investigation was to evaluate the effect of nitrogen form, maize row spacing and herbicide treatment on weed and maize biomass and water usage, as well as maize yield. The investigation was conducted at the Maize Research Institute Zemun Polje, Belgrade during 2014-2016. A field experiment was set up as a split-split-plot block design with four replications. The maize hybrid ZP388 was planted, and a standard and a slow-release form of urea were applied. For each N source, maize was grown at two row spacings: narrow of 50 cm, and standard of 70 cm, while weed control treatments included: C - without herbicide application, T - application of a pre-emergence mix of herbicides. Sowing was done in the second decade of April, 2014, 2015 and 2016. Six weeks after herbicide application, the fresh biomass of weeds uprooted from 1 m2 and aboveground biomass of ten crop plants per plot were measured together with dry matter after drying in a laboratory oven. Water content (% in weed and maize plants was calculated as a relation between fresh and dry biomass. Maize yield was measured at the end of each growing season and calculated with 14% of moisture. All data were processed by ANOVA. The fresh and dry biomass of weeds were significantly (P>0.05 higher in untreated control than in the treated variant, while differences in water content were not significant between the two treatments. Row spacing and urea form did not cause significant differences in weed parameters. Related to this, maize fresh and dry biomass, as well as water content, were higher in herbicide-treated variants than in control but differences were insignificant. Maize biomass was somewhat higher in 50 cm rows and after application of the slow-release urea fertilizer. Yield was higher from 70 cm rows and after application of

  10. Foliar copper uptake by maize plants: effects on growth and yield

    Directory of Open Access Journals (Sweden)

    Rogério Hidalgo Barbosa

    2013-09-01

    Full Text Available A slight increase in the levels of a certain nutrient can cause a significant increase in crop yield or can cause phytotoxicity symptoms. Thus, the aim of this study was to evaluate the effect of foliar application of copper (Cu on the growth and yield of DG-501 maize. The experiment was carried out between December 2009 and April 2010 in conventional tillage. When plants were with six to eight leaves, Cu (0, 100, 200, 300, 400, 500 and 600g ha-1 was applied to the leaves. Treatments were arranged in randomized complete block with five replications. When 50% of the plants were in flowering, it was evaluated the plant height, culm diameter, height of the first ear insertion, leaf area, and chlorophyll content. At harvest, it was evaluated diameter and length of the ear, yield and thousand grain weight. There was a linear reduction in the plant height and in the height of the first ear insertion with increasing Cu doses. On the other hand, chlorophyll content, leaf area, diameter and length of ear, thousand grain weight and yield increased at doses up to 100g ha-1 Cu, however, decreased at higher doses. Therefore, foliar Cu application at doses higher than 100g ha-1 has toxic effect in maize plants with losses in growth and yield.

  11. Water and nitrogen use efficiency under limited water supply for maize to increase land productivity

    International Nuclear Information System (INIS)

    Craciun, I.; Craciun, M.

    1995-01-01

    As drought is the main environmental factor limiting productivity, the study of plant response to water deficit has been one of the major research topics. The increasing of maize evapotranspiration ET does not always mean the increase of efficiency because, the brightest ET value does not always mean the highest grain yield value, AS the result of the mechanisms relating to the grain yield and ET which are far from simple. The rain amount and distribution during the reproductive stage is the main meteorological factor in flouncing yield. In our study 1991, the high soil moisture content determines a reduction of maize grain yield, in the wet years due to excess of water under irrigation conditions which normally limits root development as a result of insufficient oxygen for transpiration and lac ha of nitrate formation, the yield response to water deficit of different hybrids is of major importance in production planing. The available water supply would be directed towards fully meeting requirements of the hybrids with the higher K sub y over the restricted area and for the hybrids with a lower K sub y, the overall production will increase by extending the area under irrigation, without fully meeting water requirement provided water deficit do not exceed critical values.1 tab; 9 figs (Author)

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

    Science.gov (United States)

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

    2016-01-01

    Water uptake by mature barley grains initiates germination and is the first stage in the malting process. Here we have investigated the effects of starchy endosperm cell wall thickness on water uptake, together with the effects of varying amounts of the wall polysaccharide, (1,3;1,4)-β-glucan. In the latter case, we examined mutant barley lines from a mutant library and transgenic barley lines in which the (1,3;1,4)-β-glucan synthase gene, HvCslF6, was down-regulated by RNA interference. Neither cell wall thickness nor the levels of grain (1,3;1,4)-β-glucan were significantly correlated with water uptake but are likely to influence modification during malting. However, when a barley mapping population was phenotyped for rate of water uptake into grain, quantitative trait locus (QTL) analysis identified specific regions of chromosomes 4H, 5H and 7H that accounted for approximately 17%, 18% and 11%, respectively, of the phenotypic variation. These data indicate that variation in water uptake rates by elite malting cultivars of barley is genetically controlled and a number of candidate genes that might control the trait were identified under the QTL. The genomics data raise the possibility that the genetic variation in water uptake rates might be exploited by breeders for the benefit of the malting and brewing industries. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  13. Dissolution of different zinc salts and zn uptake by Sedum alfredii and maize in mono- and co-cropping under hydroponic culture.

    Science.gov (United States)

    Jiang, Cheng'ai; Wu, Qitang; Zeng, Shucai; Chen, Xian; Wei, Zebin; Long, Xinxian

    2013-09-01

    Previous soil pot and field experiments demonstrated that co-cropping the hyperaccumulator Sedum alfredii with maize increased Zn phytoextraction by S. alfredii and decreased Zn uptake by maize shoots. This hydroponic experiment was conducted to investigate whether the facilitation of Zn phytoextraction by S. alfredii resulted from improved dissolution in this co-cropping system and its relation to root exudates. S. alfredii and maize were mono- and co-cropped (without a root barrier) in nutrient solution spiked with four Zn compounds, ZnS, ZnO, Zn3(PO4)2 and 5ZnO x 2CO3-4H2O (represented as ZnCO3) at 1000 mg/L Zn for 15 days without renewal of nutrient solution after pre-culture. The root exudates were collected under incomplete sterilization and analyzed. The results indicated that the difference in Zn salts had a greater influence on the Zn concentration in maize than for S. alfredii, varying from 210-2603 mg/kg for maize shoots and 6445-12476 mg/kg for S. alfredii in the same order: ZnCO3 > ZnO > Zn3(PO4)2 > ZnS. For the four kinds of Zn sources in this experiment, co-cropping with maize did not improve Zn phytoextraction by S. alfredii. In most cases, compared to co-cropped and mono-cropped maize, mono-cropped S. alfredii resulted in the highest Zn2+ concentration in the remaining nutrient solution, and also had a higher total concentration of low molecular weight organic acids (LMWOA) and lower pH of root exudation. Root exudates did partly influence Zn hyperaccumulation in S. alfredii.

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

    Science.gov (United States)

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

  15. Uptake, translocation and biotransformation kinetics of BDE-47, 6-OH-BDE-47 and 6-MeO-BDE-47 in maize (Zea mays L.)

    International Nuclear Information System (INIS)

    Xu, Xuehui; Wen, Bei; Huang, Honglin; Wang, Sen; Han, Ruixia; Zhang, Shuzhen

    2016-01-01

    This study presents a detailed kinetic investigation on the uptake, acropetal translocation and transformation of BDE-47, 6-OH-BDE-47 and 6-MeO-BDE-47 in maize (Zea mays L.) by hydroponic exposure. Root uptake followed the order: BDE-47 > 6-MeO-BDE-47 > 6-OH-BDE-47, while 6-OH-BDE-47 was the most prone to acropetal translocation. Debromination rates of BDE-47 were 1.31 and 1.46 times greater than the hydroxylation and methoxylation rates, respectively. Transformation from BDE-47 to lower brominated OH/MeO-PBDEs occurred mainly through debromination first followed by hydroxylation or methoxylation. There was no transformation from 6-OH-BDE-47 or 6-MeO-BDE-47 to PBDEs. Methylation rate of 6-OH-BDE-47 was twice as high as that of 6-MeO-BDE-47 hydroxylation, indicating methylation of 6-OH-BDE-47 was easier and more rapid than hydroxylation of 6-MeO-BDE-47. Debromination and isomerization were potential metabolic pathways for 6-OH-BDE-47 and 6-MeO-BDE-47 in maize. This study provides important information for better understanding the mechanism on plant uptake and transformation of PBDEs. - Highlights: • Uptake and translocation of BDE-47 and 6-OH/MeO-BDE-47 were analog-specific. • Debromination was the fast and dominant metabolic reaction of BDE-47 in maize. • Metabolic pathways of BDE-47, 6-OH/MeO-BDE-47 in maize were discussed. • Metabolic processes should be considered in exploring phytoremediation strategy. - This article provides direct in vivo evidences of bioaccumulation and biotransformation of PBDEs, OH-PBDEs and MeO-PBDEs in plants.

  16. Forest Transpiration: Resolving Species-Specific Root Water Uptake Patterns

    Science.gov (United States)

    Blume, T.; Heidbuechel, I.; Simard, S.; Guntner, A.; Weiler, M.; Stewart, R. D.

    2016-12-01

    Transpiration and its spatio-temporal variability are still not fully understood, despite their importance for the global water cycle. This is in part due to our inability to measure transpiration comprehensively. Transpiration is usually either estimated with empirical equations based on climatic variables and crop factors, by measuring sap velocities, estimating sap wood area and scaling up to the forest stand based on a number of assumptions or by measuring the integral signal across a footprint with eddy flux towers. All these methods are focused on the cumulated loss of water to the atmosphere and do not provide information on where this water is coming from. In this study, spatio-temporal variability of root water uptake was investigated in a forest in the northeastern German lowlands. The soils are sandy and the depth of the unsaturated zone ranges from 1 to 30 m. We estimated root water uptake from different soil depths, from 0.1 m down to 2 m, based on diurnal fluctuations in soil moisture content during rain-free days. The 15 field sites cover different topographic positions and forest stands: 4 pure stands of both mature and young beech and pine and 9 mixed stands. The resulting daily data set of root water uptake shows that the forest stands differ in total amounts as well as in uptake depth distributions. Temporal dynamics of signal strength within the profile suggest a locally shifting spatial distribution of uptake that changes with water availability. The relationship of these depth-resolved uptake rates to overall soil water availability varies considerably between tree species. Using the physically-based soil hydrological model HYDRUS we investigated to what extent the observed patterns in uptake can be related to soil physical relationships alone and where tree species-specific aspects come into play. We furthermore used the model to test assumptions and estimate uncertainties of this soil moisture based estimation of plant water uptake. The

  17. Plant water relations I: uptake and transport

    Science.gov (United States)

    Plants, like all living things, are mostly water. Water is the matrix of life, and its availability determines the distribution and productivity of plants on earth. Vascular plants evolved structures that enable them to transport water long distances with little input of energy, but the hollow trach...

  18. Uptake of {sup 137}Cs by fresh water fish

    Energy Technology Data Exchange (ETDEWEB)

    Man, C.K.; Kwok, Y.H

    2000-02-01

    The uptake and discharge rates of {sup 137}Cs by fresh water fish at different radionuclide concentrations have been studied. A dual compartment model was used to fit the experimental data. The discharge rates have been found to be negligible for the duration of the experiment of 10 days. The uptake rates were independent of radionuclide concentrations for a particular type of fresh water fish and were different for different types of fish. The uptake rates of carp, tilapia and snakehead were 1.58, 1.66 and 2.23, in unit of 10{sup -6} h{sup -1}, respectively. It was also estimated that the consumption of fresh water fish, even if the water were contaminated as much as that in the Chernobyl accident, leads to negligible latent cancer fatality to the Hong Kong population.

  19. Uptake of tritiated lysine by fresh water alga, Scenedesmus obliquus

    International Nuclear Information System (INIS)

    Gogate, S.S.; Krishnamoorthy, T.M.

    1983-01-01

    Tritium uptake by fresh water alga. S.obliquus was studied using tritium labelled lysine, and a sequential solvent extraction procedure was used to study the distribution of tritium in different organic constituents of the algal cells. The accumulation of tritium in the algal cells was found to be 3-4 orders of magnitude more than that obtained for tritiated water. (author)

  20. 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 ...

  1. EFFECT OF ALUMINUM ON PLANT GROWTH, PHOSPORUS AND CALCIUM UPTAKE OF TROPICAL RICE (Oryza sativa, MAIZE (Zea mays, AND SOYBEAN (Glycine max

    Directory of Open Access Journals (Sweden)

    D. Nursyamsi

    2018-01-01

    Full Text Available Aluminum toxicity is the most limiting factor to plant growth on acid soils. Structural and functional damages in the root system by Al decrease nutrient uptake and lead to reduce plant growth and mineral deficiency in shoot. Greenhouse experiment was conducted to study the effect of Al on plant growth, and P and Ca uptake of rice, maize, and soybean. The plants were grown in hydroponic solution added with 0, 5, 10, and 30 ppm Al, at pH 4.0. The results showed that relative growth of shoots and roots of upland rice, lowland rice, maize, and soybean decreased with an increase of Al level. However, sometimes the low Al level (5 ppm stimulated shoot and root growth of some varieties in these species. According to total AlRG30 values, which is Al concentration in solution when relative growth decreased to 50%, Al tolerance of species was in order of barley < maize < soybean < lowland rice < upland rice. For maize, Al tolerance was in the order of Arjuna < Kalingga < P 3540 < SA 5 < SA 4 < PM 95 A < SA 3 < Antasena; for soybean was Wilis < INPS < Galunggung < Kerinci < Kitamusume; for lowland rice was RD 23 < Kapuas < Cisadane < KDML 105 < IR 66 < RD 13, and for upland rice was Dodokan < JAC165 < Cirata < Orizyca sabana 6 < Danau Tempe < Laut Tawar. Based on the rank of Al tolerance, rice was the useful crop to be planted in acid soils. Antasena (maize, Kitamusume ( soybean , RD 13 (lowland rice, and Laut Tawar (upland rice were also recommended for acid soils. P and Ca concentration in shoots and roots commonly decreased with an increase of Al level. However, the low Al level stimulated absorption of P and Ca concentrations in shoots and roots.

  2. Inoculation of arbuscular mycorrhizal fungi and phosphate solubilizing bacteria in the presence of rock phosphate improves phosphorus uptake and growth of maize

    International Nuclear Information System (INIS)

    Wahid, F.; Sharif, M.; Khan, M. A.; Khan, S. A.

    2016-01-01

    The beneficial microbes like arbuscular mycorrhizal fungi (AMF) and phosphate solubilizing bacteria (PSB) are known to play an important role in phosphorous (P) supply to plants in a sustainable manner in P deficient soils. In this scenario, a pot experiment was conducted under greenhouse condition to assess the synergistic effect of AMF and PSB strains (Coccus DIM7 Streptococcus PIM6 and Bacillus sp. PIS7) on P solubility from RP and their successive uptake by maize (Zea-mays L. Azam) crop at alkaline soil. The experiment was completely randomized design with three replications having calcareous silty clay loam soil, low in organic matter, nitrogen and phosphorus contents. RP was used as a crude phosphate alone and/or in combination with the native AMF and PSB inoculum. The Results indicated that the rhizosphere interactions between AMF and PSB significantly promote RP mineralization in soil and improved all growth parameters including shoot (56 percent), root yield (52 percent), height (41 percent), N (80 percent) and P (91 percent) uptake by the maize plants as compared to control and single inoculation. A remarkable increase in soil spore density, PSB population and percent root colonization in maize plants were also recorded by the combined inoculation of AMF and PSB with RP. From this study, it is concluded that the combined application of AMF and PSB with RP has the potential to improve maize growth and nutrients uptake. Moreover, AMF and PSB inoculants are recommended as useful biofertilizers for enhancing P solubility and bioavailability in P deficient agricultural soils. (author)

  3. Water uptake and motion in highly densified bentonite

    International Nuclear Information System (INIS)

    Kahr, G.; Mueller-Vonmoos, F.; Kraehenbuehl, F.; Stoeckli, H.F.

    1986-07-01

    Water uptake by the bentonites MX-80 and Montigel was investigated according to the classical method of determination of the heat immersion and the adsorption-desorption isotherms. In addition, the layer expansion of the montmorillonite was measured as a function of the water content. The evaluation of the adsorption isotherms according to Dubinin-Radushkevich and the stratification distances determined by x-ray confirmed gradual water uptake. Up to 10% water content, the water is adsorbed as a monolayer, up to 20%, as a bimolecular layer around the interlayer cations. The partial specific entropy could be determined from the approximative calculation of the partial specific enthalpy from the heats of immersion and the free enthalpy from the adsorption isotherms. From this it is evident that the interlayer water shows a high degree of order. In this condition, the mobility of the water molecules is considerably lower than in free water. From the adsorption isotherm and the layer expansion observed, it can be assumed that water can appear in the pore space only from approximately 25% water content. The spaces outwith the interlayer space and the surfaces of the montmorillonite particles are considered as pore space. If free swelling is prevented and with dry densities greater than 1.8 Mg/m/sup 3/ for the highly compacted bentonites, water uptake causes a drastic reduction of the original pore space so that practically all the water is in the interlayer space. Calculation of the swelling pressure from the adsorption isotherms gives a good approximation of the measured swelling pressures. A montmorillonite surface of ca. 750 m/sup 2//g for both bentonites can be derived from a Dubinin-Radushkevich analysis of the adsorption isotherm. Water uptake into the compacted unsaturated bentonites can be described as diffusion with a diffusion coefficient of the order of magnitude of 3.10/sup -10/ m/sup 2//s. (author)

  4. Effect of moisture content of concrete on water uptake

    International Nuclear Information System (INIS)

    Rucker-Gramm, P.; Beddoe, R.E.

    2010-01-01

    The penetration of water and non-polar hexane in Portland cement mortar prisms with different initial moisture contents was investigated using nuclear magnetic resonance ( 1 H NMR). The amount of water in gel pores strongly affects the penetration of water in much larger capillary pores. Water penetration is reduced by the self-sealing effect as characterized by non-√t dependence of capillary uptake and penetration depth. This is explained by the ongoing redistribution of water from capillaries into gel pores which results in internal swelling and loss of continuity of the capillary pore system; a correlation was observed between the amount of redistributed water and departure from √t behaviour. A descriptive model is used to explain the dependence of water uptake and penetration on moisture content. For increasing initial moisture contents up to a critical value equivalent to equilibrium with a relative humidity between 65 and 80%, less penetrating water is able to redistribute. Thus more penetrating water is in larger capillaries with less viscous resistance; uptake and penetration depth increase. Above the critical initial moisture content, uptake and penetration depth decrease towards zero. This is explained by (a) an overall reduction in capillary pressure because transport takes places in fewer and larger pores and (b) an increase in viscous resistance due to the connection of penetrating capillary water with pores already containing water. Less capillary pore space is available for transport. The surface region of concrete placed in contact with water is not instantaneously saturated. Water content increases with time depending on the degree of surface saturation. A new transition coefficient for capillary suction γ is defined for the calculation of surface flux.

  5. The effect of modifying rooting depths and nitrification inhibitors on nutrient uptake from organic biogas residues in maize

    Science.gov (United States)

    Dietrich, Charlotte C.; Koller, Robert; Nagel, Kerstin A.; Schickling, Anke; Schrey, Silvia D.; Jablonowski, Nicolai D.

    2017-04-01

    Optimizing the application of and nutrient uptake from organic nutrient sources, such as the nutrient-rich residues ("digestates") from the biogas industry, is becoming a viable option in remediating fertility on previously unsuitable soils for agricultural utilization. Proposedly, concurrent changes in root system architecture and functioning could also serve as the basis of future phytomining approaches. Herein, we evaluate the effect of spatial nutrient availability and nitrification on maize root architecture and nutrient uptake. We test these effects by applying maize-based digestate at a rate of 170 kg/ha in layers of varying depths (10, 25 and 40 cm) and through either the presence or absence of nitrification inhibitors. In order to regularly monitor above- and below-ground plant biomass production, we used the noninvasive phenotyping platform, GROWSCREEN-Rhizo at the Forschungszentrum Jülich, using rhizotrons (Nagel et al., 2012). Measured parameters included projected plant height and leaf area, as well as root length and spatial distribution. Additionally, root diameters were quantified after the destructive harvest, 21 days after sowing (DAS). Spatial nutrient availability significantly affected root system architecture, as for example root system size -the area occupied by roots- increased alongside nutrient layer depths. Fertilization also positively affected root length density (RLD). Within fertilized layers, the presence of nitrification inhibitors increased RLD by up to 30% and was most pronounced in the fine root biomass fraction (0.1 to 0.5mm). Generally, nitrification inhibitors promoted early plant growth by up to 45% across treatments. However, their effect varied in dependence of layer depths, leading to a time-delayed response in deeper layers, accounting for plants having to grow significantly longer roots in order to reach fertilized substrate. Nitrification inhibitors also initiated the comparatively early on-set of growth differences in

  6. A simple three-dimensional macroscopic root water uptake model based on the hydraulic architecture approach

    Directory of Open Access Journals (Sweden)

    V. Couvreur

    2012-08-01

    Full Text Available Many hydrological models including root water uptake (RWU do not consider the dimension of root system hydraulic architecture (HA because explicitly solving water flow in such a complex system is too time consuming. However, they might lack process understanding when basing RWU and plant water stress predictions on functions of variables such as the root length density distribution. On the basis of analytical solutions of water flow in a simple HA, we developed an "implicit" model of the root system HA for simulation of RWU distribution (sink term of Richards' equation and plant water stress in three-dimensional soil water flow models. The new model has three macroscopic parameters defined at the soil element scale, or at the plant scale, rather than for each segment of the root system architecture: the standard sink fraction distribution SSF, the root system equivalent conductance Krs and the compensatory RWU conductance Kcomp. It clearly decouples the process of water stress from compensatory RWU, and its structure is appropriate for hydraulic lift simulation. As compared to a model explicitly solving water flow in a realistic maize root system HA, the implicit model showed to be accurate for predicting RWU distribution and plant collar water potential, with one single set of parameters, in dissimilar water dynamics scenarios. For these scenarios, the computing time of the implicit model was a factor 28 to 214 shorter than that of the explicit one. We also provide a new expression for the effective soil water potential sensed by plants in soils with a heterogeneous water potential distribution, which emerged from the implicit model equations. With the proposed implicit model of the root system HA, new concepts are brought which open avenues towards simple and mechanistic RWU models and water stress functions operational for field scale water dynamics simulation.

  7. Uptake of uranium from sea water by Synechococcus elongatus

    International Nuclear Information System (INIS)

    Horikoshi, Takao; Nakajima, Akira; Sakaguchi, Takashi

    1979-01-01

    Basic features of the uranium uptake by Synechococcus elongatus, and the factors affecting it were examined. Synechococcus elongatus was grown in Roux flasks containing 1 liter of culture solution in light (20,000 lux) and with aeration at 30 deg C. Synechococcus cells in the linear growth phase were collected by centrifugation at 6,000 x g for 5 minutes, washed with sea water, and used for the uranium-uptake experiments. The uptake of uranium from sea water containing 1 ppm of the element was strongly affected by the pH of sea water. The optimum uptake was at pH 5. Presence of carbonate ions markedly inhibited and decarbonation of sea water greatly enhanced the uptake. Absorption of uranium by Synechococcus cells was initially rapid, and reached a plateau within 24 hours. The uranium accumulation capacity of Synechococcus cells was increased by heat treatment, the capacity of scalded cells being about twice as much as that of living cells. Most of the uranium absorbed by Synechococcus was found in the inner space of the cells, and only a small amount was present in the cell walls. (Kaihara, S.)

  8. Influence of arbuscular mycorrhizae on photosynthesis and water status of maize plants under salt stress.

    Science.gov (United States)

    Sheng, Min; Tang, Ming; Chen, Hui; Yang, Baowei; Zhang, Fengfeng; Huang, Yanhui

    2008-09-01

    The influence of arbuscular mycorrhizal (AM) fungus Glomus mosseae on characteristics of the growth, water status, chlorophyll concentration, gas exchange, and chlorophyll fluorescence of maize plants under salt stress was studied in the greenhouse. Maize plants were grown in sand and soil mixture with five NaCl levels (0, 0.5, 1.0, 1.5, and 2.0 g/kg dry substrate) for 55 days, following 15 days of non-saline pretreatment. Under salt stress, mycorrhizal maize plants had higher dry weight of shoot and root, higher relative chlorophyll content, better water status (decreased water saturation deficit, increased water use efficiency, and relative water content), higher gas exchange capacity (increased photosynthetic rate, stomatal conductance and transpiration rate, and decreased intercellular CO(2) concentration), higher non-photochemistry efficiency [increased non-photochemical quenching values (NPQ)], and higher photochemistry efficiency [increased the maximum quantum yield in the dark-adapted state (Fv/Fm), the maximum quantum yield in the light-adapted sate (Fv'/Fm'), the actual quantum yield in the light-adapted steady state (phiPSII) and the photochemical quenching values (qP)], compared with non-mycorrhizal maize plants. In addition, AM symbiosis could trigger the regulation of the energy biturcation between photochemical and non-photochemical events reflected in the deexcitation rate constants (kN, kN', kP, and kP'). All the results show that G. mosseae alleviates the deleterious effect of salt stress on plant growth, through improving plant water status, chlorophyll concentration, and photosynthetic capacity, while the influence of AM symbiosis on photosynthetic capacity of maize plants can be indirectly affected by soil salinity and mycorrhizae-mediated enhancement of water status, but not by the mycorrhizae-mediated enhancement of chlorophyll concentration and plant biomass.

  9. Effect of the foliar enrichment and herbicides on maize and associated weeds irrigated with drainage water

    Directory of Open Access Journals (Sweden)

    Roshdy M.H. Tagour

    2017-12-01

    Full Text Available A two-year field experiment was conducted during summer seasons of 2013 and 2014, which were irrigated by drainage water which belong to salinity class (C3S1 to C4S2, to study the effect of the foliar enrichment namely (Anti-stress and weed management treatments (some pre and post-emergence herbicides and two-hand hoeing on maize growth, yield, yield components and chemical composition of maize grains and associated weeds (Portulaca oleracea, Amaranthus retroflexus and Echinochloa colonum. The results illustrated that application of the foliar enrichment enhanced the dry weight of weeds and increased maize growth characters, yield and yield components and total crude protein and total oil percentage of grain maize, as compared with untreated treatment. All weed management treatments caused a significant reduction in total dry weight of weeds at 60 and 80 days after sowing in both seasons. Two-hand hoeing treatment exerted the highest decrease in total dry weight of weeds followed by metribuzin, oxadiagyl, fluroxypyr and bentazon, respectively at 60 and 80 days after sowing compared with other weed management treatments. While, the highest values of maize growth, yield, yield components and maize grains' content of protein and oil was obtained with two-hand hoeing followed by metribuzin, oxadiagyl, fluroxypyr and bentazon, respectively. While, two hands hoeing produced the maximum values of leaf area, ear length, the weight of kernels plant−1, but applying of metribuzin treatment gave the highest values of total oil percentage of grain maize when the foliar enrichment was used.

  10. Uptake of uranium from sea water by microalgae

    International Nuclear Information System (INIS)

    Sakaguchi, Takashi; Horikoshi, Takao; Nakajima, Akira

    1978-01-01

    The uptake of uranium from aqueous systems especially from sea water by various microalgae was investigated. The freshwater microalgae, Chlorella regularis, Scenedesmus bijuga, Scenedesmus chloreloides, Scenedesmus obliquus, Chlamydomonas angulosa, Chlamydomonas reinhardtii, accumulated relatively large amounts of uranium from the solution containing uranium only. The concentration factors of the above mentioned algae were: Chlorella regularis 3930, Chlamydomonas 2330 - 3400, Scenedesmus 803 - 1920. The uptake of uranium from sea water by Chlorella regularis was inhibited markedly by the co-existence of carbonate ions. Chlorella cells could take up a great quantity of uranium from decarbonated sea water. The uptake of uranium was affected by the pH of sea water, and the amount of uranium absorbed was maximum at pH 5. The experiment was carried out to screen marine microalgae which have the ability to accumulate a large amount of uranium from sea water. The uptake of uranium from sea water by marine microalgae of different species turned out to be in the following decreasing order: Synechococcus > Chlamydomonas >> Chlorella > Dunaliella > Platymonas > Calothrix > Porphyridium. The amount of uranium absorbed differed markedly with different species of marine microalgae. (author)

  11. Dynamics of Short-Term Phosphorus Uptake by Intact Mycorrhizal and Non-mycorrhizal Maize Plants Grown in a Circulatory Semi-Hydroponic Cultivation System.

    Science.gov (United States)

    Garcés-Ruiz, Mónica; Calonne-Salmon, Maryline; Plouznikoff, Katia; Misson, Coralie; Navarrete-Mier, Micaela; Cranenbrouck, Sylvie; Declerck, Stéphane

    2017-01-01

    A non-destructive cultivation system was developed to study the dynamics of phosphorus (Pi) uptake by mycorrhizal and non-mycorrhizal maize plantlets. The system consisted of a plant container connected via silicon tubes to a glass bottle containing a nutrient solution supplemented with Pi. The nutrient solution is pumped with a peristaltic pump to the upper part of the container via the silicon tubes and the solution percolate through the plantlet container back into the glass bottle. Pi is sampled from the glass bottle at regular intervals and concentration evaluated. Maize plantlets were colonized by the AMF Rhizophagus irregularis MUCL 41833 and Pi uptake quantified at fixed intervals (9, 21, and 42 h) from the depletion of the Pi in the nutrient solution flowing through the plantlets containers. Plants and fungus grew well in the perlite substrate. The concentration of Pi in the bottles followed an almost linear decrease over time, demonstrating a depletion of Pi in the circulating solution and a concomitant uptake/immobilization by the plantlet-AMF associates in the containers. The Pi uptake rate was significantly increased in the AMF-colonized plantlets (at 9 and 21 h) as compared to non-colonized plantlets, although no correlation was noticed with plant growth or P accumulation in shoots. The circulatory semi-hydroponic cultivation system developed was adequate for measuring Pi depletion in a nutrient solution and by corollary Pi uptake/immobilization by the plant-AMF associates. The measurements were non-destructive so that the time course of Pi uptake could be monitored without disturbing the growth of the plant and its fungal associate. The system further opens the door to study the dynamics of other micro and macro-nutrients as well as their uptake under stressed growth conditions such as salinity, pollution by hydrocarbon contaminants or potential toxic elements.

  12. Dynamics of Short-Term Phosphorus Uptake by Intact Mycorrhizal and Non-mycorrhizal Maize Plants Grown in a Circulatory Semi-Hydroponic Cultivation System

    Directory of Open Access Journals (Sweden)

    Mónica Garcés-Ruiz

    2017-08-01

    Full Text Available A non-destructive cultivation system was developed to study the dynamics of phosphorus (Pi uptake by mycorrhizal and non-mycorrhizal maize plantlets. The system consisted of a plant container connected via silicon tubes to a glass bottle containing a nutrient solution supplemented with Pi. The nutrient solution is pumped with a peristaltic pump to the upper part of the container via the silicon tubes and the solution percolate through the plantlet container back into the glass bottle. Pi is sampled from the glass bottle at regular intervals and concentration evaluated. Maize plantlets were colonized by the AMF Rhizophagus irregularis MUCL 41833 and Pi uptake quantified at fixed intervals (9, 21, and 42 h from the depletion of the Pi in the nutrient solution flowing through the plantlets containers. Plants and fungus grew well in the perlite substrate. The concentration of Pi in the bottles followed an almost linear decrease over time, demonstrating a depletion of Pi in the circulating solution and a concomitant uptake/immobilization by the plantlet-AMF associates in the containers. The Pi uptake rate was significantly increased in the AMF-colonized plantlets (at 9 and 21 h as compared to non-colonized plantlets, although no correlation was noticed with plant growth or P accumulation in shoots. The circulatory semi-hydroponic cultivation system developed was adequate for measuring Pi depletion in a nutrient solution and by corollary Pi uptake/immobilization by the plant-AMF associates. The measurements were non-destructive so that the time course of Pi uptake could be monitored without disturbing the growth of the plant and its fungal associate. The system further opens the door to study the dynamics of other micro and macro-nutrients as well as their uptake under stressed growth conditions such as salinity, pollution by hydrocarbon contaminants or potential toxic elements.

  13. Extensive tissue-specific transcriptomic plasticity in maize primary roots upon water deficit

    OpenAIRE

    Opitz, Nina; Marcon, Caroline; Paschold, Anja; Malik, Waqas Ahmed; Lithio, Andrew; Brandt, Ronny; Piepho, Hans-Peter; Nettleton, Dan; Hochholdinger, Frank

    2015-01-01

    Water deficit is the most important environmental constraint severely limiting global crop growth and productivity. This study investigated early transcriptome changes in maize (Zea mays L.) primary root tissues in response to moderate water deficit conditions by RNA-Sequencing. Differential gene expression analyses revealed a high degree of plasticity of the water deficit response. The activity status of genes (active/inactive) was determined by a Bayesian hierarchical model. In total, 70% o...

  14. Water fluxes in maize, millet and soybean plant-residue mulches used in direct seeding

    International Nuclear Information System (INIS)

    Silva, Fernando Antonio Macena da; Pinto, Hilton Silveira; Scopel, Eric; Corbeels, Marc; Affholder, Francois

    2006-01-01

    The objective of this work was to evaluate the effects of crop residue mulches from maize, millet and soybean on water storage capacity, water evaporation, soil cover, solar radiation interception and surface water run-off as well as to incorporate these effects in a crop growth model. The mulch of millet and maize presented higher capacity for water storage than soybean mulch: 3.26, 3.24 and 2.62 g of water per gram of dry matter, respectively. Water losses from wet mulches were related to the potential evapotranspiration. The soil cover levels were similar among the three types of material. The three types of mulch intercepted similar quantities of photosynthetically active radiation and infrared radiation. The mulch of maize straw was slightly more efficient in intercepting radiation than that from millet or soybean. Mulching with millet residues was efficient in the control of surface water run-off: only 45.5 mm of water (out of 843.5 mm rainfall) was lost through runoff under the no-till system with millet as cover crop, whereas 222.5 mm of water was lost in the conventional system with tillage. Most of the relations derived in this work could be described by exponential models. (author)

  15. Rainfall and crop modeling-based water stress assessment for rainfed maize cultivation in peninsular India

    Science.gov (United States)

    Manivasagam, V. S.; Nagarajan, R.

    2018-04-01

    Water stress due to uneven rainfall distribution causes a significant impact on the agricultural production of monsoon-dependent peninsular India. In the present study, water stress assessment for rainfed maize crop is carried out for kharif (June-October) and rabi (October-February) cropping seasons which coincide with two major Indian monsoons. Rainfall analysis (1976-2010) shows that the kharif season receives sufficient weekly rainfall (28 ± 32 mm) during 26th-39th standard meteorological weeks (SMWs) from southwest monsoon, whereas the rabi season experiences a major portion of its weekly rainfall due to northeast monsoon between the 42nd and 51st SMW (31 ± 42 mm). The later weeks experience minimal rainfall (5.5 ± 15 mm) and thus expose the late sown maize crops to a severe water stress during its maturity stage. Wet and dry spell analyses reveal a substantial increase in the rainfall intensity over the last few decades. However, the distribution of rainfall shows a striking decrease in the number of wet spells, with prolonged dry spells in both seasons. Weekly rainfall classification shows that the flowering and maturity stages of kharif maize (33rd-39th SMWs) can suffer around 30-40% of the total water stress. In the case of rabi maize, the analysis reveals that a shift in the sowing time from the existing 42nd SMW (16-22 October) to the 40th SMW (1-7 October) can avoid terminal water stress. Further, AquaCrop modeling results show that one or two minimal irrigations during the flowering and maturity stages (33rd-39th SMWs) of kharif maize positively avoid the mild water stress exposure. Similarly, rabi maize requires an additional two or three lifesaving irrigations during its flowering and maturity stages (48th-53rd SMWs) to improve productivity. Effective crop planning with appropriate sowing time, short duration crop, and high yielding drought-resistant varieties will allow for better utilization of the monsoon rain, thus reducing water stress with

  16. Uptake of uranium from drinking water

    International Nuclear Information System (INIS)

    Singh, N.P.; Wrenn, M.E.

    1987-01-01

    The gastrointestinal absorption (G.I.) of uranium in man from drinking water was determined by measuring urinary and fecal excretion of 234 U and 238 U in eight subjects. In order to establish their normal backgrounds of uranium intake and excretion the subjects collected 24 hour total output of both urine and feces for seven days prior to drinking water. During the next day they drank, at their normal rate of drinking water intake, 900 ml of water containing approximately 90 pCi 238 U and 90 pCi 234 U (274 μg U) and continued to collect their urine and feces for seven additional days. Utilizing one technique for analyzing data, the G.I. absorption of 234 U ranged from -0.07% to 1.88% with an average of 0.51% and G.I. absorption of 238 U ranged from -0.07% to 1.79% with an average of 0.50%. Employing another technique for analyzing the data, the G.I. absorption ranged from -0.04 to 1.46% with a mean of 0.53% for 234 U and from 0.03% to 1.43% with a mean of 0.52 for 238 U. The dietary intake of U was also estimated from measurements of urinary and fecal excretion of U in eight subjects prior to drinking water containing U. The estimated average dietary intake of U for these subjects is 3.30 +/- 0.65 or 4.22 +/- 0.65 μg/day. These averages are two to four times higher than the values reported in the literature for dietary intake

  17. Uptake and metabolism of [14C]-aspartate by developing kernels of maize (Zea mays L.)

    International Nuclear Information System (INIS)

    Muhitch, M.J.

    1990-01-01

    Pulse-chase experiments were performed to determine the metabolic fate of [14C]-aspartate in the pedicel region and subsequent uptake into the endosperm. Kernels were removed from the cob, leaving the pedicel attached but removing glumes, palea, and lemma. The basal tips were incubated in [14C]-aspartate for 0.5 h, followed by a 2 h chase period with unlabeled aspartate. In contrast to a previous study in which 70% of the 14C from aspartate was recovered in the organic acid fraction (Lyznik, et al., Phytochemistry 24: 425, 1985), only 20 to 25% of the radioactivity found in the 2 h chase period. While a small amount of the 14C transiently appeared in alanine at the beginning of the chase period, the most heavily labeled non-fed amino acid was glutamine, which accounted for 21% of the radioactivity within the pedicel amino acid fraction by 0.5 h into the chase period. There was no evidence for asparagine synthesis within the pedicel region of the kernel. 14C recovered from the endosperm in the form of amino acids were aspartate (60%), glutamine (20%), glutamate (15%), and alanine (5%). These results suggest that some of the maternally supplied amino acids undergo metabolic conversion to other amino acids before being taken up by the endosperm

  18. Soil loss by water erosion in areas under maize and jack beans intercropped and monocultures

    Directory of Open Access Journals (Sweden)

    Pedro Luiz Terra Lima

    2014-04-01

    Full Text Available Adequate soil management can create favorable conditions to reduce erosion and water runoff, consequently increase water soil recharge. Among management systems intercropping is highly used, especially for medium and small farmers. It is a system where two or more crops with different architectures and vegetative cycles are explored simultaneously at the same location. This research investigated the effects of maize intercropped with jack bean on soil losses due to water erosion, estimate C factor of Universal Soil Losses Equation (USLE and how it can be affected by soil coverage. The results obtained also contribute to database generation, important to model and estimate soil erosion. Total soil loss by erosion caused by natural rain, at Lavras, Minas Gerais, Brazil, were: 4.20, 1.86, 1.38 and 1.14 Mg ha-1, respectively, for bare soil, maize, jack bean and the intercropping of both species, during evaluated period. Values of C factor of USLE were: 0.039, 0.054 and 0.077 Mg ha Mg-1 ha-1 for maize, jack bean and intercropping between both crops, respectively. Maize presented lower vegetation cover index, followed by jack beans and consortium of the studied species. Intercropping between species showed greater potential on soil erosion control, since its cultivation resulted in lower soil losses than single crops cultivation, and this aspect is really important for small and medium farmers in the studied region.

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

    Directory of Open Access Journals (Sweden)

    Antonio Odair Santos

    1999-12-01

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

  20. The Uptake by Plants of Diethylstilboestrol and of Its Glucuronide

    DEFF Research Database (Denmark)

    Gregers Hansen, B.

    1964-01-01

    The uptake of diethylstilboestrol and its glucuronide by plants could, under certain circumstances, present a potential health hazard. The relative uptake of the two compounds has therefore been studied in rye grass, red clover, mushrooms, and maize in pot and water culture experiments. It is con......The uptake of diethylstilboestrol and its glucuronide by plants could, under certain circumstances, present a potential health hazard. The relative uptake of the two compounds has therefore been studied in rye grass, red clover, mushrooms, and maize in pot and water culture experiments...

  1. Effect of readily available water deficit in soil on maize yield and evapotranspiration

    Directory of Open Access Journals (Sweden)

    Pejić Borivoj

    2010-01-01

    Full Text Available An investigation was carried out at Rimski Šančevi experiment field of Institute of Field and Vegetable Crops, Novi Sad on calcareous chernozem soil on the loess terrace, in the period 2000-2007, and included irrigated variant (T1 and non-irrigated i.e. control variant (T0. NS-640, maize hybrid from the FAO maturity group 600, was analyzed. Readily available soil water deficit (RASWD in the layer of 60 cm in the course of growing season and actual evapotranspiration (ETa were calculated by the water balance method. Water consumption for potential evapotranspiration (ETm in individual months and the growing season were calculated by the bioclimatic procedure, using hydrophytothermic indexes. The correlation analysis revealed highly significant dependences of maize yield (Y on RASWD (r = -0.941 and the amount of precipitation (P in August (r = 0.931. Statistically significant dependence was also found between Y and RASWD (r = -0.765 and P (r = 0.768 in July and August. The obtained results indicate that maize production in Vojvodina under the rainfed conditions is unreliable, and that it is correlated with weather conditions, especially with the amount and distribution of precipitation. The statistically significant correlation obtained between Y and ETa (r = 0.755 confirms that water supply is the basic prerequisite which allows the other production factors to be realized. Significantly higher maize yields in the T1 variant (13.517 t ha-1 in relation to the T0 variant (11.210 t ha-1 indicate clearly that under the climatic conditions of Vojvodina high and stable yields of maize can be achieved only in irrigation. .

  2. Water requirements for wheat and maize under climate change in North Nile Delta

    Energy Technology Data Exchange (ETDEWEB)

    Ouda, S.; Noreldin, T; Abd El-Latif, K.

    2015-07-01

    Determination of water requirements for wheat and maize under climate change is important for policy makers in Egypt. The objectives of this paper were to calculate (i) ETo and (ii) water requirements for wheat and maize crops grown in five governorates (Alexandria, Demiatte, Kafr El-Sheik, El-Dakahlia and El-Behira) located in North Nile Delta of Egypt under current climate and climate change. ECHAM5 climate model was used to develop A1B climate change scenario in 2020, 2030 and 2040. Monthly values of evapotranspiration (ETo) under the different scenarios in these governorates were calculated using Hargreaves-Samani equation (H-S). Then, these values were regressed on ETo values previously calculated by Penman-Monteith equation (P-M) and linear regression (prediction equations were developed for each governorate). The predicted ETo values were compared to the values of ETo calculated by P-M equation and the deviations between them were very low (RMSE/obs=0.04-0.06 mm and R2 =0.96-0.99). Water requirements for wheat and maize were calculated using BISm model under current climate and in 2020, 2030 and 2040. The results showed that average annual ETo would increase by low percentage in 2020 and 2030. However, in 2040 the increase would reach 8%. Water requirements are expected to increase by 2-3% for wheat and by 10-15% for maize, which would result in reduction of the cultivated area. Thus, it is very important to revise and fix the production system of wheat and maize, in terms of the used cultivars, fertilizer and irrigation application to overcome the risk of climate change. (Author)

  3. Zebrafish ( Danio rerio) as a model for investigating the safety of GM feed ingredients (soya and maize); performance, stress response and uptake of dietary DNA sequences.

    Science.gov (United States)

    Sissener, Nini H; Johannessen, Lene E; Hevrøy, Ernst M; Wiik-Nielsen, Christer R; Berdal, Knut G; Nordgreen, Andreas; Hemre, Gro-Ingunn

    2010-01-01

    A 20-d zebrafish (Danio rerio) feeding trial, in which a near doubling of fish weight was achieved, was conducted with GM feed ingredients to evaluate feed intake, growth, stress response and uptake of dietary DNA. A partial aim of the study was to assess zebrafish as a model organism in GM safety assessments. Roundup Ready soya (RRS), YieldGard Bt maize (MON810) and their non-modified, maternal, near-isogenic lines were used in a 2 x 2 factorial design. Soya variety and maize variety were the main factors, both with two levels; non-GM and GM. Compared with fish fed non-GM maize, those fed GM maize exhibited significantly better growth, had lower mRNA transcription levels of superoxide dismutase (SOD)-1 and a tendency (non-significant) towards lower transcription of heat shock protein 70 in liver. Sex of the fish and soya variety had significant interaction effects on total RNA yield from the whole liver and transcription of SOD-1, suggesting that some diet component affecting males and females differently was present in different levels in the GM and the non-GM soya used in the present study. Dietary DNA sequences were detected in all of the organs analysed, but not all of the samples. Soya and maize rubisco (non-transgenic, multicopy genes) were most frequently detected, while MON810 transgenic DNA fragments were detected in some samples and RRS fragments were not detected. In conclusion, zebrafish shows promise as a model for this application.

  4. Water deficit effects on maize yields modeled under current and greenhouse climates

    International Nuclear Information System (INIS)

    Muchow, R.C.; Sinclair, T.R.

    1991-01-01

    The availability of water imposes one of the major limits on rainfed maize (Zea mays L.) productivity. This analysis was undertaken in an attempt to quantify the effects of limited water on maize growth and yield by extending a simple, mechanistic model in which temperature regulates crop development and intercepted solar radiation is used to calculate crop biomass accumulation. A soil water budget was incorporated into the model by accounting for inputs from rainfall and irrigation, and water use by soil evaporation and crop transpiration. The response functions of leaf area development and crop gas exchange to the soil water budget were developed from experimental studies. The model was used to interpret a range of field experiments using observed daily values of temperature, solar radiation, and rainfall or irrigation, where water deficits of varying durations developed at different stages of growth. The relative simplicity of the model and its robustness in simulating maize yields under a range of water-availability conditions allows the model to be readily used for studies of crop performance under alternate conditions. One such study, presented here, was a yield assessment for rainfed maize under possible greenhouse climates where temperature and atmospheric CO 2 concentration were increased. An increase in temperature combined with decreased rainfall lowered grain yield, although the increase in crop water use efficiency associated with elevated CO 2 concentration ameliorated the response to the greenhouse climate. Grain yields for the greenhouse climates as compared to current conditions increased, or decreased only slightly, except when the greenhouse climate was assumed to result in severly decreased rainfall

  5. Plant–Water Relations (1): Uptake and Transport

    Science.gov (United States)

    2014-01-01

    Summary Plants, like all living things, are mostly water. Water is the matrix of life, and its availability determines the distribution and productivity of plants on earth. Vascular plants evolved structures that enable them to transport water long distances with little input of energy, but the hollow tracheary elements are just one of many adaptations that enable plants to cope with a very dry atmosphere. This lecture examines the physical laws that govern water uptake and transport, the biological properties of cells and plant tissues that facilitate it, and the strategies that enable plants to survive in diverse environments

  6. Enhanced water stress tolerance of transgenic maize plants over-expressing LEA Rab28 gene.

    Science.gov (United States)

    Amara, Imen; Capellades, Montserrat; Ludevid, M Dolors; Pagès, Montserrat; Goday, Adela

    2013-06-15

    Late Embryogenesis Abundant (LEA) proteins participate in plant stress responses and contribute to the acquisition of desiccation tolerance. In this report Rab28 LEA gene has been over-expressed in maize plants under a constitutive maize promoter. The expression of Rab28 transcripts led to the accumulation and stability of Rab28 protein in the transgenic plants. Native Rab28 protein is localized to nucleoli in wild type maize embryo cells; here we find by whole-mount immunocytochemistry that in root cells of Rab28 transgenic and wild-type plants the protein is also associated to nucleolar structures. Transgenic plants were tested for stress tolerance and resulted in sustained growth under polyethyleneglycol (PEG)-mediated dehydration compared to wild-type controls. Under osmotic stress transgenic seedlings showed increased leaf and root areas, higher relative water content (RWC), reduced chlorophyll loss and lower Malondialdehyde (MDA) production in relation to wild-type plants. Moreover, transgenic seeds exhibited higher germination rates than wild-type seeds under water deficit. Overall, our results highlight the presence of transgenic Rab28 protein in nucleolar structures and point to the potential of group 5 LEA Rab28 gene as candidate to enhance stress tolerance in maize plants. Copyright © 2013 Elsevier GmbH. All rights reserved.

  7. Uptake, translocation and biotransformation kinetics of BDE-47, 6-OH-BDE-47 and 6-MeO-BDE-47 in maize (Zea mays L.).

    Science.gov (United States)

    Xu, Xuehui; Wen, Bei; Huang, Honglin; Wang, Sen; Han, Ruixia; Zhang, Shuzhen

    2016-01-01

    This study presents a detailed kinetic investigation on the uptake, acropetal translocation and transformation of BDE-47, 6-OH-BDE-47 and 6-MeO-BDE-47 in maize (Zea mays L.) by hydroponic exposure. Root uptake followed the order: BDE-47 > 6-MeO-BDE-47 > 6-OH-BDE-47, while 6-OH-BDE-47 was the most prone to acropetal translocation. Debromination rates of BDE-47 were 1.31 and 1.46 times greater than the hydroxylation and methoxylation rates, respectively. Transformation from BDE-47 to lower brominated OH/MeO-PBDEs occurred mainly through debromination first followed by hydroxylation or methoxylation. There was no transformation from 6-OH-BDE-47 or 6-MeO-BDE-47 to PBDEs. Methylation rate of 6-OH-BDE-47 was twice as high as that of 6-MeO-BDE-47 hydroxylation, indicating methylation of 6-OH-BDE-47 was easier and more rapid than hydroxylation of 6-MeO-BDE-47. Debromination and isomerization were potential metabolic pathways for 6-OH-BDE-47 and 6-MeO-BDE-47 in maize. This study provides important information for better understanding the mechanism on plant uptake and transformation of PBDEs. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. 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.

  9. Solar-Induced Fluorescence of Maize Across A Water Stress Gradient in the Midwestern USA

    Science.gov (United States)

    Miao, G.; Guan, K.; Suyker, A.; Yang, X.; Benarcchi, C. J.; Gamon, J. A.; Berry, J. A.; DeLucia, E.; Franz, T.; Arkebauer, T. J.; Zygielbaum, A. I.; Walter-Shea, E. A.; Moore, C.; Zhang, Y.; Kim, H.; Hmimina, G.

    2017-12-01

    In the coming decades, agricultural ecosystems will be challenged by rising temperatures, changing rainfall patterns, and increasing extreme weather. Understanding how crops respond to weather variability and how humans manage agriculture to mitigate and adapt to climate change is critical for improving agricultural sustainability and supporting increasing global food demands. Accurately estimating gross primary productivity (GPP) of crops is of importance to evaluate their sustainability and capability but remains a challenge. The recent development of solar-induced fluorescence (SIF) technology is stimulating studies to use SIF to approximate GPP. It has been observed that agricultural lands have remarkably high SIF and the SIF signal could be used as an indicator of vegetation stress, which is particularly valuable for improved monitoring of crop productivity and stress. To investigate the applicability of SIF for detecting maize stress and estimating GPP, we deployed three FluoSpec2 systems in 2017 at three long-term eddy covariance flux sites across the US Corn Belt, a rain-fed maize field (AmeriFlux sites US-NE3) and an irrigated maize field (US-NE2) at Mead, Nebraska and a rain-fed maize field at Urbana, Illinois. Together these form a water stress gradient. Variations in GPP, SIF, photosynthetic efficiency (LUE), SIF yield (SIFy), and relationships between GPP and SIF, LUE and SIFy will be compared as indications of the difference in maize growth across the water stress gradient. More importantly, differences in GPP and SIF signals will be examined over multiple growth stages to assess the potential of SIF in identifying the growth stages that are mostly affected by water stress and the ones that play the most important roles on the crop yield.

  10. Changes to soil water content and biomass yield under combined maize and maize-weed vegetation with different fertilization treatments in loam soil

    Directory of Open Access Journals (Sweden)

    Lehoczky Éva

    2016-06-01

    Full Text Available Especially during early developmental stages, competition with weeds can reduce crop growth and have a serious effect on productivity. Here, the effects of interactions between soil water content (SWC, nutrient availability, and competition from weeds on early stage crop growth were investigated, to better understand this problem. Field experiments were conducted in 2013 and 2014 using long-term study plots on loam soil in Hungary. Plots of maize (Zea mays L. and a weed-maize combination were exposed to five fertilization treatments. SWC was observed along the 0–80 cm depth soil profile and harvested aboveground biomass (HAB was measured.

  11. Spatio-temporal dynamics of maize yield water constraints under climate change in Spain.

    Science.gov (United States)

    Ferrero, Rosana; Lima, Mauricio; Gonzalez-Andujar, Jose Luis

    2014-01-01

    Many studies have analyzed the impact of climate change on crop productivity, but comparing the performance of water management systems has rarely been explored. Because water supply and crop demand in agro-systems may be affected by global climate change in shaping the spatial patterns of agricultural production, we should evaluate how and where irrigation practices are effective in mitigating climate change effects. Here we have constructed simple, general models, based on biological mechanisms and a theoretical framework, which could be useful in explaining and predicting crop productivity dynamics. We have studied maize in irrigated and rain-fed systems at a provincial scale, from 1996 to 2009 in Spain, one of the most prominent "hot-spots" in future climate change projections. Our new approach allowed us to: (1) evaluate new structural properties such as the stability of crop yield dynamics, (2) detect nonlinear responses to climate change (thresholds and discontinuities), challenging the usual linear way of thinking, and (3) examine spatial patterns of yield losses due to water constraints and identify clusters of provinces that have been negatively affected by warming. We have reduced the uncertainty associated with climate change impacts on maize productivity by improving the understanding of the relative contributions of individual factors and providing a better spatial comprehension of the key processes. We have identified water stress and water management systems as being key causes of the yield gap, and detected vulnerable regions where efforts in research and policy should be prioritized in order to increase maize productivity.

  12. Modeling the effects of different irrigation water salinity on soil water movement, uptake and multicomponent solute transport

    Science.gov (United States)

    Lekakis, E. H.; Antonopoulos, V. Z.

    2015-11-01

    Simulation models can be important tools for analyzing and managing irrigation, soil salinization or crop production problems. In this study a mathematical model that describes the water movement and mass transport of individual ions (Ca2+, Mg2+ and Na+) and overall soil salinity by means of the soil solution electrical conductivity, is used. The mass transport equations of Ca2+, Mg2+ and Na+ have been incorporated as part of the integrated model WANISIM and the soil salinity was computed as the sum of individual ions. The model was calibrated and validated against field data, collected during a three year experiment in plots of maize, irrigated with three different irrigation water qualities, at Thessaloniki area in Northern Greece. The model was also used to evaluate salinization and sodification hazards by the use of irrigation water with increasing electrical conductivity of 0.8, 3.2 and 6.4 dS m-1, while maintaining a ratio of Ca2+:Mg2+:Na+ equal to 3:3:2. The qualitative and quantitative procedures for results evaluation showed that there was good agreement between the simulated and measured values of the water content, overall salinity and the concentration of individual soluble cations, at two soil layers (0-35 and 35-75 cm). Nutrient uptake was also taken into account. Locally available irrigation water (ECiw = 0.8 dS m-1) did not cause soil salinization or sodification. On the other hand, irrigation water with ECiw equal to 3.2 and 6.4 dS m-1 caused severe soil salinization, but not sodification. The rainfall water during the winter seasons was not sufficient to leach salts below the soil profile of 110 cm. The modified version of model WANISIM is able to predict the effects of irrigation with saline waters on soil and plant growth and it is suitable for irrigation management in areas with scarce and low quality water resources.

  13. Effects of magnetized water application on soil and maize growth indices under different amounts of salt in the water

    Directory of Open Access Journals (Sweden)

    Meysam Abedinpour

    2017-09-01

    Full Text Available Application of low quality water for irrigation is compulsive in facing water scarcity. Use of a magnetic field is an approach to overcome this challenge. This study examined the impact of magnetic field technology on improving germination under water of different salinity levels. An experiment was conducted to determine the effects of saline water levels, i.e. (S1:0.5, (S2:2, (S3:4 and (S4:6 dS/m combined with magnetized technology (with or without on maize growth. Thus, magnetic treatment was applied by passing the irrigation water through a 1,500 mT magnetic field at 3 litres per minute (lpm flow rate. Some emergence indices, such as emergence index, emergence rate index (ERI and mean emergence time, were used to evaluate the germination of maize seed. As for soil properties after plant harvest, the use of magnetically treated irrigation water reduced soil pH but increased soil electrical conductivity and available N and P. ERI increased from 7.6 to 10.2, 9.1 to 11.1, 10.3 to 13.3, and 11.8 to 13.3 when applying the magnetized field for S1, S2, S3 and S4, respectively. Overall, the growth parameters of maize were improved by using magnetic technology with saline water, while the opposite trend was shown for increasing salinity without magnetic treatment.

  14. Silicon induced improvement in morpho-physiological traits of maize (zea mays l.) under water deficit

    International Nuclear Information System (INIS)

    Amin, M.; Ahmad, R.; Basra, S.M.A.; Murtaza, G.

    2014-01-01

    Current water scarcity is an emerging issue in semi-arid regions like Pakistan and cause of deterioration in productivity of crops to reduce crop yield all over the world. Silicon is known to be better against the deleterious effects of drought on plant growth and development. A pot study was conducted to evaluate the effect of Si nutrition (0, 50, 100 and 150 mg/kg) on the growth of a relatively drought tolerant (P-33H25) and sensitive (FH-810) maize hybrids. Two levels of soil water content were used viz. 100 and 60% of field capacity. Water deficit condition in soil significantly reduced morphological and physiological attributes of maize plants. Silicon application significantly improved the plant height, leaf area per plant, primary root length, dry matter of shoot and roots and plant dry matter, water relation and gas exchange characteristics of both maize cultivars under water deficit condition. Poor growth of drought stressed plants was significantly improved with Si application. The silicon fertilized (100 mg/kg) drought stressed plants of hybrid P-33H25 produced maximum (21.68% more) plant dry matter as compared to plants that were not provided with silicon nutrition. Nonetheless, silicon application (150 mg/kg) resulted in maximum increase (26.03%) in plant dry weight of hybrid FH-810 plants that were grown under limited moisture supply i.e., 60% FC. In conclusion silicon application to drought stressed maize plants was better to improve the growth and dry matter could be attributed to improved osmotic adjustment, photosynthetic rate and lowered transpiration. (author)

  15. Changing water availability during the African maize-growing season, 1979–2010

    International Nuclear Information System (INIS)

    Estes, Lyndon D; Chaney, Nathaniel W; Herrera-Estrada, Julio; Sheffield, Justin; Caylor, Kelly K; Wood, Eric F

    2014-01-01

    Understanding how global change is impacting African agriculture requires a full physical accounting of water supply and demand, but accurate, gridded data on key drivers (e.g., humidity) are generally unavailable. We used a new bias-corrected meteorological dataset to analyze changes in precipitation (supply), potential evapotranspiration (E p , demand), and water availability (expressed as the ratio P/E p ) in 20 countries (focusing on their maize-growing regions and seasons), between 1979 and 2010, and the factors driving changes in E p . Maize-growing areas in Southern Africa, particularly South Africa, benefitted from increased water availability due in large part to demand declines driven primarily by declining net radiation, increasing vapor pressure, and falling temperatures (with no effect from changing windspeed), with smaller increases in supply. Sahelian zone countries in West Africa, as well as Ethiopia in East Africa, had strong increases in availability driven primarily by rainfall rebounding from the long-term Sahelian droughts, with little change or small reductions in demand. However, intra-seasonal supply variability generally increased in West and East Africa. Across all three regions, declining net radiation contributed downwards pressure on demand, generally over-riding upwards pressure caused by increasing temperatures, the regional effects of which were largest in East Africa. A small number of countries, mostly in or near East Africa (Tanzania and Malawi) experienced declines in water availability primarily due to decreased rainfall, but exacerbated by increasing demand. Much of the reduced water availability in East Africa occurred during the more sensitive middle part of the maize-growing season, suggesting negative consequences for maize production. (paper)

  16. An assessment of the effect of human faeces and urine on maize production and water productivity

    Science.gov (United States)

    Guzha, Edward; Nhapi, Innocent; Rockstrom, Johan

    The key challenge facing many catchment authorities in Zimbabwe and elsewhere is the challenge of feeding the growing populations within their catchment boundaries. Modern agricultural practices continue to mine valuable crop nutrients through increased food production to satisfy ever-increasing food demand. In recent diagnostic survey of smallholder agricultural sector in the Manyame catchments of Zimbabwe it was revealed that exhausted soils depleted of their natural mineral and organic constituents by many years of cropping with little fertilization or manuring were the major factors contributing to low yields and poor food security in this sector in Zimbabwe. The objective of the study was to assess the effect of using sanitized human excreta on maize production and water productivity. The study involved six volunteer farmers with four 10 m × 10 m trial plots each with the following treatments the control, commercial fertilizer treatment urine only plot, and the feacal matter and urine plot. Harvest determination was carried by weighing the yield from each of the treatment plots and comparisons done. Water productivity was computed by calculating the amount of water used to produce a tone of maize per ha. The study showed that human excreta improves maize crop production and water productivity in rain-fed agriculture. The study recommends that the ecological sanitation concept and the reuse of human excreta both humanure and (ecofert) urine can be considered as alternative excreta management options in catchment areas.

  17. Modelling soil water dynamics and crop water uptake at the field level

    NARCIS (Netherlands)

    Kabat, P.; Feddes, R.A.

    1995-01-01

    Parametrization approaches to model soil water dynamics and crop water uptake at field level were analysed. Averaging and numerical difficulties in applying numerical soil water flow models to heterogeneous soils are highlighted. Simplified parametrization approaches to the soil water flow, such as

  18. Efficiency of ammonium nitrate phosphates of varying water-soluble phosphorous content for wheat and succeeding maize crop on different soil types

    International Nuclear Information System (INIS)

    Chapke, V.G.; Bhujbal, B.M.; Mistry, K.B.

    1988-01-01

    Efficiency of 32 P labelled ammonium nitrate phosphate (ANP) containding 30, 50 and 90 per cent of water-soluble phosphorus (WSP) vis-a-vis that of entirely water soluble monoammonium orthophosphate (MAP) for wheat and succeeding maize crop on deep black (vertisol), calcareous black (vertisol), alluvial-Tarai (mollisol) and grey brown alluvial (aridisol) soils was examined in greenhouse experiments. Data on wheat indicated that ANP (50 per cent WSP) was, in general, equally efficient to MAP and ANP (90 per cent WSP) in terms of drymatter yield and total uptake of phosphorus in all soils examined, however, the per cent utilization of applied fertilizer was significantly higher for MAP and ANP (90 per cent WSP) than those for ANP (50 per cent WSP) in all soils. In general, ANP (30 per cent WSP) was significantly inferior to MAP and ANP (90 per cent WSP) in all soils. Data on the succeeding maize crop grown to flowering indicated that residual value of ANP (30 per cent WSP) was equal to that of MAP and ANP (90 per cent WSP) in terms of drymatter yield and phosphorus uptake by the four soils examined. Complementary incubation studies conducted upto 60 days on the above four soils at field capacity moisture status indicated highest 0.5 M NaHCO 3 (pH 8.5) extractable phosphorus levels in MAP treatments followed by ANP (50 per cent WSP) and least in ANP (30 per cent WSP) treatments. (author). 4 tables, 4 figures, 19 refs

  19. SOIL WATER BALANCE APPROACH IN ROOT ZONE OF MAIZE (95 ...

    African Journals Online (AJOL)

    DR. AMINU

    It is usual practice to use available soil water content as a criterion for deciding when irrigation is needed. Soil water content is determined by using soil measuring techniques (capacitance probe) that describe the depletion of available soil water see fig1 and 2. The irrigation scheduling is based on the water treatment (i.e. ...

  20. 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

  1. How Does Silicon Mediate Plant Water Uptake and Loss Under Water Deficiency?

    Directory of Open Access Journals (Sweden)

    Daoqian Chen

    2018-03-01

    Full Text Available In plants, water deficiency can result from a deficit of water from the soil, an obstacle to the uptake of water or the excess water loss; in these cases, the similar consequence is the limitation of plant growth and crop yield. Silicon (Si has been widely reported to alleviate the plant water status and water balance under variant stress conditions in both monocot and dicot plants, especially under drought and salt stresses. However, the underlying mechanism is unclear. In addition to the regulation of leaf transpiration, recently, Si application was found to be involved in the adjustment of root hydraulic conductance by up-regulating aquaporin gene expression and concentrating K in the xylem sap. Therefore, this review discusses the potential effects of Si on both leaf transpiration and root water absorption, especially focusing on how Si modulates the root hydraulic conductance. A growing number of studies support the conclusion that Si application improves plant water status by increasing root water uptake, rather than by decreasing their water loss under conditions of water deficiency. The enhancement of plant water uptake by Si is achievable through the activation of osmotic adjustment, improving aquaporin activity and increasing the root/shoot ratio. The underlying mechanisms of the Si on improving plant water uptake under water deficiency conditions are discussed.

  2. Effects of magnetized water application on soil and maize growth indices under different amounts of salt in the water

    OpenAIRE

    Meysam Abedinpour; Ebrahim Rohani

    2017-01-01

    Application of low quality water for irrigation is compulsive in facing water scarcity. Use of a magnetic field is an approach to overcome this challenge. This study examined the impact of magnetic field technology on improving germination under water of different salinity levels. An experiment was conducted to determine the effects of saline water levels, i.e. (S1):0.5, (S2):2, (S3):4 and (S4):6 dS/m combined with magnetized technology (with or without) on maize growth. Thus, magnetic treatm...

  3. Hydraulic root water uptake models: old concerns and new insights

    Science.gov (United States)

    Couvreur, V.; Carminati, A.; Rothfuss, Y.; Meunier, F.; Vanderborght, J.; Javaux, M.

    2014-12-01

    Root water uptake (RWU) affects underground water dynamics, with consequences on plant water availability and groundwater recharge. Even though hydrological and climate models are sensitive to RWU parameters, no consensus exists on the modelling of this process. Back in the 1940ies, Van Den Honert's catenary approach was the first to investigate the use of connected hydraulic resistances to describe water flow in whole plants. However concerns such as the necessary computing when architectures get complex made this approach premature. Now that computing power increased dramatically, hydraulic RWU models are gaining popularity, notably because they naturally produce observed processes like compensatory RWU and hydraulic redistribution. Yet major concerns remain. Some are more fundamental: according to hydraulic principles, plant water potential should equilibrate with soil water potential when the plant does not transpire, which is not a general observation when using current definitions of bulk or average soil water potential. Other concerns regard the validation process: water uptake distribution is not directly measurable, which makes it hard to demonstrate whether or not hydraulic models are more accurate than other models. Eventually parameterization concerns exist: root hydraulic properties are not easily measurable, and would even fluctuate on an hourly basis due to processes like aquaporin gating. While offering opportunities to validate hydraulic RWU models, newly developed observation techniques also make us realize the increasing complexity of processes involved in soil-plant hydrodynamics, such as the change of rhizosphere hydraulic properties with soil drying. Surprisingly, once implemented into hydraulic models, these processes do not necessarily translate into more complex emerging behavior at plant scale, and might justify the use of simplified representations of the soil-plant hydraulic system.

  4. Extensive tissue-specific transcriptomic plasticity in maize primary roots upon water deficit.

    Science.gov (United States)

    Opitz, Nina; Marcon, Caroline; Paschold, Anja; Malik, Waqas Ahmed; Lithio, Andrew; Brandt, Ronny; Piepho, Hans-Peter; Nettleton, Dan; Hochholdinger, Frank

    2016-02-01

    Water deficit is the most important environmental constraint severely limiting global crop growth and productivity. This study investigated early transcriptome changes in maize (Zea mays L.) primary root tissues in response to moderate water deficit conditions by RNA-Sequencing. Differential gene expression analyses revealed a high degree of plasticity of the water deficit response. The activity status of genes (active/inactive) was determined by a Bayesian hierarchical model. In total, 70% of expressed genes were constitutively active in all tissues. In contrast, deficit-responsive genes (1915) were consistently regulated in all tissues, while >75% (1501 genes) were specifically regulated in a single root tissue. Water deficit-responsive genes were most numerous in the cortex of the mature root zone and in the elongation zone. The most prominent functional categories among differentially expressed genes in all tissues were 'transcriptional regulation' and 'hormone metabolism', indicating global reprogramming of cellular metabolism as an adaptation to water deficit. Additionally, the most significant transcriptomic changes in the root tip were associated with cell wall reorganization, leading to continued root growth despite water deficit conditions. This study provides insight into tissue-specific water deficit responses and will be a resource for future genetic analyses and breeding strategies to develop more drought-tolerant maize cultivars. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  5. Arsenic contamination in irrigation water, agricultural soil and maize crop from an abandoned smelter site in Matehuala, Mexico.

    Science.gov (United States)

    Ruíz-Huerta, Esther Aurora; de la Garza Varela, Alonso; Gómez-Bernal, Juan Miguel; Castillo, Francisco; Avalos-Borja, Miguel; SenGupta, Bhaskar; Martínez-Villegas, Nadia

    2017-10-05

    Mobility of Arsenic (As) from metallurgical wastes in Matehuala, Mexico has been accounted for ultra-high concentration of As in water (4.8-158mg/L) that is used for recreational purposes as well as cultivation of maize. In this study, we (i) measured As concentrations in soils irrigated with this water, (ii) investigated the geochemical controls of available As, and (iii) measured bioaccumulation of As in maize. Water, soil, and maize plant samples were collected from 3 different plots to determine As in environmental matrices as well as water soluble As in soils. Soil mineralogy was determined by X-ray diffraction analysis. Bioaccumulation of As in maize plants was estimated from the bioconcentration and translocation factors. We recorded As built-up in agricultural soils to the extent of 172mg/kg, and noted that this As is highly soluble in water (30% on average). Maize crops presented high bioaccumulation, up to 2.5 times of bioconcentration and 45% of translocation. Furthermore, we found that water extractable As was higher in soils rich in calcite, while it was lower in soils containing high levels of gypsum, but As bioconcentration showed opposite trend. Results from this study show that irrigation with As rich water represents a significant risk to the population consuming contaminated crops. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Water satisfaction analysis for dryland maize production in Frankfort

    CSIR Research Space (South Africa)

    Moeletsi, ME

    2010-09-01

    Full Text Available and the atmospheric demand. To assess crop performance based on water available to the crop during the growing season the water requirement satisfaction index (WRSI) was developed by the Food and Agriculture Organization (FAO) as documented in the FAO Plant...

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

    African Journals Online (AJOL)

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

  8. Effects Of Irrigation With Saline Water, And Soil Type On Germination And Seedling Growth Of Sweet Maize (Zea Mays L.)

    International Nuclear Information System (INIS)

    Mostafa, A.Z.; Amato, M.; Hamdi, A.; Mostafa, A.Z.; Galal, Y.G.M.; Lotfy, S.M.

    2012-01-01

    Germination and early growth of maize Sweet Maize (Zea mays L.), var. (SEL. CONETA) under irrigation with saline water were investigated in a pot experiment with different soil types. Seven salinity levels of irrigation water up to 12 dS/m were used on a Clay soil (C) and a Sandy-Loam (SL). Emergence of maize was delayed under irrigation with saline water, and the final percentage of germination was reduced only at 8 dS/m or above. Seedling shoot and root growth were reduced starting at 4 dS/m of irrigation water. Salts accumulated more in the C soil but reductions in final germination rate and seedling growth were larger in the SL soil, although differences were not always significant. Data indicate that germination is rather tolerant to salinity level in var. SEL. CONETA whereas seedling growth is reduced at moderate salinity levels, and that soil type affects plant performance under irrigation with saline water

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

    Science.gov (United States)

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

    2017-04-01

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

  10. Spatio-temporal dynamics of maize yield water constraints under climate change in Spain.

    Directory of Open Access Journals (Sweden)

    Rosana Ferrero

    Full Text Available Many studies have analyzed the impact of climate change on crop productivity, but comparing the performance of water management systems has rarely been explored. Because water supply and crop demand in agro-systems may be affected by global climate change in shaping the spatial patterns of agricultural production, we should evaluate how and where irrigation practices are effective in mitigating climate change effects. Here we have constructed simple, general models, based on biological mechanisms and a theoretical framework, which could be useful in explaining and predicting crop productivity dynamics. We have studied maize in irrigated and rain-fed systems at a provincial scale, from 1996 to 2009 in Spain, one of the most prominent "hot-spots" in future climate change projections. Our new approach allowed us to: (1 evaluate new structural properties such as the stability of crop yield dynamics, (2 detect nonlinear responses to climate change (thresholds and discontinuities, challenging the usual linear way of thinking, and (3 examine spatial patterns of yield losses due to water constraints and identify clusters of provinces that have been negatively affected by warming. We have reduced the uncertainty associated with climate change impacts on maize productivity by improving the understanding of the relative contributions of individual factors and providing a better spatial comprehension of the key processes. We have identified water stress and water management systems as being key causes of the yield gap, and detected vulnerable regions where efforts in research and policy should be prioritized in order to increase maize productivity.

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

    Directory of Open Access Journals (Sweden)

    Guanghao Li

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

  12. Uptake of antibiotics from irrigation water by plants

    DEFF Research Database (Denmark)

    Azanu, David; Mortey, Christiana; Darko, Godfred

    2016-01-01

    The capacity of carrot (Daucus corota L.) and lettuce (Lactuca sativa L.), two plants that are usually eaten raw, to uptake tetracycline and amoxicillin (two commonly used antibiotics) from irrigated water was investigated in order to assess the indirect human exposure to antibiotics through...... tested concentrations of 0.1-15 mg L(-1). Tetracycline was detected in all plant samples, at concentrations ranging from 4.4 to 28.3 ng/g in lettuce and 12.0-36.8 ng g(-1) fresh weight in carrots. Amoxicillin showed absorption with concentrations ranging from 13.7 ng g(-1) to 45.2 ng g(-1) for the plant...

  13. Spring maize yield, soil water use and water use efficiency under plastic film and straw mulches in the Loess Plateau

    Science.gov (United States)

    Lin, Wen; Liu, Wenzhao; Xue, Qingwu

    2016-12-01

    To compare the soil water balance, yield and water use efficiency (WUE) of spring maize under different mulching types in the Loess Plateau, a 7-year field experiment was conducted in the Changwu region of the Loess Plateau. Three treatments were used in this experiment: straw mulch (SM), plastic film mulch (PM) and conventional covering without mulch (CK). Results show that the soil water change of dryland spring maize was as deep as 300 cm depth and hence 300 cm is recommended as the minimum depth when measure the soil water in this region. Water use (ET) did not differ significantly among the treatments. However, grain yield was significantly higher in PM compared with CK. WUE was significantly higher in PM than in CK for most years of the experiment. Although ET tended to be higher in PM than in the other treatments (without significance), the evaporation of water in the fallow period also decreased. Thus, PM is sustainable with respect to soil water balance. The 7-year experiment and the supplemental experiment thus confirmed that straw mulching at the seedling stage may lead to yield reduction and this effect can be mitigated by delaying the straw application to three-leaf stage.

  14. Validation of a spatial–temporal soil water movement and plant water uptake model

    KAUST Repository

    HEPPELL, J.

    2014-06-01

    © 2014, (publisher). All rights reserved. Management and irrigation of plants increasingly relies on accurate mathematical models for the movement of water within unsaturated soils. Current models often use values for water content and soil parameters that are averaged over the soil profile. However, many applications require models to more accurately represent the soil–plant–atmosphere continuum, in particular, water movement and saturation within specific parts of the soil profile. In this paper a mathematical model for water uptake by a plant root system from unsaturated soil is presented. The model provides an estimate of the water content level within the soil at different depths, and the uptake of water by the root system. The model was validated using field data, which include hourly water content values at five different soil depths under a grass/herb cover over 1 year, to obtain a fully calibrated system for plant water uptake with respect to climate conditions. When compared quantitatively to a simple water balance model, the proposed model achieves a better fit to the experimental data due to its ability to vary water content with depth. To accurately model the water content in the soil profile, the soil water retention curve and saturated hydraulic conductivity needed to vary with depth.

  15. Water requirements for wheat and maize under climate change in North Nile Delta

    Directory of Open Access Journals (Sweden)

    Samiha Ouda

    2015-03-01

    Full Text Available Determination of water requirements for wheat and maize under climate change is important for policy makers in Egypt. The objectives of this paper were to calculate (i ETo and (ii water requirements for wheat and maize crops grown in five governorates (Alexandria, Demiatte, Kafr El-Sheik, El-Dakahlia and El-Behira located in North Nile Delta of Egypt under current climate and climate change. ECHAM5 climate model was used to develop A1B climate change scenario in 2020, 2030 and 2040. Monthly values of evapotranspiration (ETo under the different scenarios in these governorates were calculated using Hargreaves-Samani equation (H-S. Then, these values were regressed on ETo values previously calculated by Penman-Monteith equation (P-M and linear regression (prediction equations were developed for each governorate. The predicted ETo values were compared to the values of ETo calculated by P-M equation and the deviations between them were very low (RMSE/obs=0.04-0.06 mm and R2 =0.96-0.99. Water requirements for wheat and maize were calculated using BISm model under current climate and in 2020, 2030 and 2040. The results showed that average annual ETo would increase by low percentage in 2020 and 2030. However, in 2040 the increase would reach 8%. Water requirements are expected to increase by 2-3% for wheat and by 10-15% for maize, which would result in reduction of the cultivated area. Thus, it is very important to revise and fix the production system of wheat and maize, in terms of the used cultivars, fertilizer and irrigation application to overcome the risk of climate change. Additional key words: Triticum spp; Zea mays; Penman-Monteith equation; Hargreaves-Samani equation; BISm model; ECHAM5 climate model; A1B climate change scenario. Abbreviations used: BISm (basic irrigation scheduling model; CCAFS (Climate Change, Agriculture and Food Security; ETo (evapotranspiration; H-S (Hargreaves & Samani; Kc (crop coefficient; PI (percentage of increase; P

  16. Increased cesium uptake by water tupelo under inundated conditions

    International Nuclear Information System (INIS)

    McLeod, K.W.

    1980-01-01

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

  17. Soil persistence, plant and non-target insect uptake of endosulfan and lindane applied to soya bean and maize in field trials in Zimbabwe

    International Nuclear Information System (INIS)

    Zaranyika, M.F.; Mugari, P.

    1997-01-01

    The persistence of lindane and endosulfan in the soil, uptake by, and distribution in plants, and effects on and absorption by non-target insects, following application of the insecticides for the control of maize pests and soya bean respectively were determined under Zimbabwean weather conditions. No large scale effects on the non-target insects were observed though some small effects on the populations of semiloopers and orthoptera in the endosulfan treated soya bean plot were noted. Concentrations of the insecticides in spiders declined during the trial though those in grasshoppers and crickets appeared to increase. Concentrations of both insecticides in soil fell rapidly during the first 7 weeks after application but, after that, the rates of loss were much slower possibly owing to the drier conditions prevailing during this later period, reducing both physicochemical and microbial loss processes. Initial concentrations of both insecticides in all the vegetative parts of plants examined after spray application declined systematically to low levels during the 10 weeks of observations, probably owing to both metabolism within the plants and to crop volume dilution effects and will have declined to even lower levels by harvest time. Surprisingly, low concentrations of lindane and endosulfan were found in the harvested maize and soya bean seeds. At early stages after application, there were also traces of both insecticides in the vegetative parts of the plants from the untreated, control plots probably arising from uptake of soil residues from the previous year and/or spray drift but these became undetectable at later stages of growth. (author). 31 refs, 7 tabs

  18. Seed quality and water use characteristics of maize landraces compared with selected commercial hybrids

    Directory of Open Access Journals (Sweden)

    Farai Mazvimbakupa

    2015-03-01

    Full Text Available Understanding seed quality and water use characteristics of maize (Zea mays L. landraces will improve food security among subsistence farmers who still cultivate them. The objective of this study was to evaluate seed quality and water use characteristics of two maize landraces (GQ1 and GQ2 compared with two commercial hybrids (SC701 and PAN53. Seed quality was determined by the standard germination, electrical conductivity, and tetrazolium tests. A controlled environment study was conducted in which the landraces were compared with hybrids across three water treatments (30% ETc; 50% ETc, and 80% ETc. Although landrace GQ2 performed at par with the hybrids, overall, seed quality tests showed that hybrids had superior seed quality than landraces. This was also confirmed by highly significant emergence results (P < 0.001 from pot trials where SC701 and PAN53 had higher emergence (100% and 94.44%, respectively compared with GQ2 (86.11% and GQ1 (61.11%. Subjecting landraces and hybrids to water stress (50% and 30% ETc resulted in shorter plants with fewer leaves and earlier tasselling compared with non-stressed plants (80% ETc. Plant height for the 30% ETc water treatment was 156.1 cm compared with 175.8 cm for the 80% ETc water treatment, while plants under the 30% ETc water treatment tasseled at 105.4 d compared with 129.5 d for the 80% ETc water treatment. The GQ2 landrace continued to perform similar to, and often better, than the hybrid varieties, especially under stress conditions. Yield was poor under controlled conditions. Performance of the GQ2 landrace for both seed quality tests and under controlled conditions shows that landraces remain an important germplasm resource.

  19. Effect of PEG-6000 Imposed Water Deficit on Chlorophyll Metabolism in Maize Leaves

    Directory of Open Access Journals (Sweden)

    Rekha Gadre

    2013-08-01

    Full Text Available Drought stress is one of the major abiotic constraint limiting plant growth and productivity world wide. The current study was undertaken with the aim to investigate the effect of water deficit imposed by PEG-6000, on chlorophyll metabolism in maize leaves to work out the mechanistic details. Leaf segments prepared from primary leaves of etiolated maize seedlings were treated with varying concentrations of polyethylene glycol-6000 (PEG-6000; w/v- 5%, 10%, 20%, 30% in continuous light of intensity 40 Wm-2 at 26±2 °C for 24 h in light chamber. The results demonstrate a concentration dependent decline in chlorophyll content with increasing concentration of polyethylene glycol-6000 (PEG-6000. Reduction in chlorophyll ‘a’ level was to a greater extent than the chlorophyll ‘b’. The RNA content decreased in a concentration dependent manner with PEG, however, proline content increased significantly. Relative water content decreased significantly with the supply of 30% PEG only. A substantial decrease in chlorophyll synthesis due to significant reduction in ALA content and ALAD activity, with no change in chlorophyllase activity with the supply of PEG suggests that water deficit affects chlorophyll formation rather than its degradation.

  20. Influence of sub-lethal crude oil concentration on growth, water relations and photosynthetic capacity of maize (Zea mays L.) plants.

    Science.gov (United States)

    Athar, Habib-Ur-Rehman; Ambreen, Sarah; Javed, Muhammad; Hina, Mehwish; Rasul, Sumaira; Zafar, Zafar Ullah; Manzoor, Hamid; Ogbaga, Chukwuma C; Afzal, Muhammad; Al-Qurainy, Fahad; Ashraf, Muhammad

    2016-09-01

    Maize tolerance potential to oil pollution was assessed by growing Zea mays in soil contaminated with varying levels of crude oil (0, 2.5 and 5.0 % v/w basis). Crude oil contamination reduced soil microflora which may be beneficial to plant growth. It was observed that oil pollution caused a remarkable decrease in biomass, leaf water potential, turgor potential, photosynthetic pigments, quantum yield of photosystem II (PSII) (Fv/Fm), net CO2 assimilation rate, leaf nitrogen and total free amino acids. Gas exchange characteristics suggested that reduction in photosynthetic rate was mainly due to metabolic limitations. Fast chlorophyll a kinetic analysis suggested that crude oil damaged PSII donor and acceptor sides and downregulated electron transport as well as PSI end electron acceptors thereby resulting in lower PSII efficiency in converting harvested light energy into biochemical energy. However, maize plants tried to acclimate to moderate level of oil pollution by increasing root diameter and root length relative to its shoot biomass, to uptake more water and mineral nutrients.

  1. Constraining water uptake depths in semiarid environments using water stable isotopes

    Science.gov (United States)

    Beyer, Matthias; Königer, Paul; Himmelsbach, Thomas

    2017-04-01

    The biophysical process of transpiration recently received increased attention by ecohydrologists as it has been proven the largest flux of the global water balance. However, fundamental aspects related to the questions how and from which sources plants receive their water are not fully understood. Especially the process of plant water uptake from deeper soil and its impact on the water balance requires increased scientific effort. In this study we combined tracer experiments with the analysis of natural isotopic compositions in order to: i) derive a suitable site-specific root water uptake distribution for hydrological modeling; ii) find indicators for groundwater use by specific plants; and iii) evaluate the importance of deep unsaturated zone water uptake using HYDRUS 1D. The bayesian mixing model MixSIAR was applied at a semiarid site with a deep unsaturated zone in northern Namibia in order to identify source water contributions of the most abundant species (A.erioloba, B.plurijuga, C.collinum, S.luebertii and T.sericea). In addition, a previously developed method for the investigation of root water uptake depths based on deuterium labeling (2H2O) at specific depths (0.5 to 4 m) and monitoring of tracer uptake by plants was carried out with a focus on the deeper unsaturated zone. With the experimental results a root water uptake distribution for the lateral root zone was derived which allows to constrain the source water contributions estimated with MixSIAR. Finally, a HYDRUS 1D model was established and unsaturated zone water transport was evaluated. The analysis of the natural isotopic compositions reveals a significant contribution of groundwater (median: 48%) to the isotopic composition of A.erioloba at the end of the dry season indicating the presence of deep tap roots for a number of individuals. All other investigated species obtain their water from the shallow (median: 22%) or deeper (median: 62%) unsaturated zone at this time of the year. The water

  2. The Impact of Rhizosphere Processes on Water Flow and Root Water Uptake

    Science.gov (United States)

    Schwartz, Nimrod; Kroener, Eva; Carminati, Andrea; Javaux, Mathieu

    2015-04-01

    For many years, the rhizosphere, which is the zone of soil in the vicinity of the roots and which is influenced by the roots, is known as a unique soil environment with different physical, biological and chemical properties than those of the bulk soil. Indeed, in recent studies it has been shown that root exudate and especially mucilage alter the hydraulic properties of the soil, and that drying and wetting cycles of mucilage result in non-equilibrium water dynamics in the rhizosphere. While there are experimental evidences and simplified 1D model for those concepts, an integrated model that considers rhizosphere processes with a detailed model for water and roots flow is absent. Therefore, the objective of this work is to develop a 3D physical model of water flow in the soil-plant continuum that take in consideration root architecture and rhizosphere specific properties. Ultimately, this model will enhance our understanding on the impact of processes occurring in the rhizosphere on water flow and root water uptake. To achieve this objective, we coupled R-SWMS, a detailed 3D model for water flow in soil and root system (Javaux et al 2008), with the rhizosphere model developed by Kroener et al (2014). In the new Rhizo-RSWMS model the rhizosphere hydraulic properties differ from those of the bulk soil, and non-equilibrium dynamics between the rhizosphere water content and pressure head is also considered. We simulated a wetting scenario. The soil was initially dry and it was wetted from the top at a constant flow rate. The model predicts that, after infiltration the water content in the rhizosphere remained lower than in the bulk soil (non-equilibrium), but over time water infiltrated into the rhizosphere and eventually the water content in the rhizosphere became higher than in the bulk soil. These results are in qualitative agreement with the available experimental data on water dynamics in the rhizosphere. Additionally, the results show that rhizosphere processes

  3. Analysis of virtual water flows associated with the trade of maize in the SADC region: importance of scale

    Directory of Open Access Journals (Sweden)

    J. M. Dabrowski

    2009-10-01

    Full Text Available The concept of virtual water encourages a country to view agricultural crops in terms of the amount of water required to produce those crops, with a view to implementing trading policies that promote the saving of scarce water resources. Recently, increased attention has focussed on partitioning the virtual water content of crops into green and blue water (derived from rainfall and irrigation, respectively as the latter has higher opportunity costs associated with its use and therefore impacts directly on scarcity. Maize is the most important crop traded within the SADC region. South Africa is the largest producer and exporter of maize, with the majority of its exports destined for other SADC countries. In comparison to other SADC countries, South Africa produces maize relatively efficiently, with a low virtual water content and a high green (868 m3 t−1 to blue (117 m3 t−1 water ratio. The blue water content is however higher than for maize produced in all other SADC countries, with the exception of Namibia (211 m3 t−1. Current trade patterns therefore result in a net expenditure of blue water (66×106 m3, almost all of which is exported by South Africa (65×106 m3. South Africa is one of the most water scarce countries in the region and analysis of virtual water flows indicates that current SADC maize trading patterns are influenced by national productivity as opposed to water scarcity. The virtual water content of maize was estimated for each of South Africa's nineteen Water Management Area's (WMA and used as a proxy to represent water use efficiency for maize production. The virtual water content varied widely across all of the WMAs, ranging from 360 m3 t−1 in the Ustutu Mhlatuze to 1000 m3 t−1 in the Limpopo. A comparison of the virtual water content and production of maize

  4. Water uptake by salts during the electrolyte processing for thermal batteries

    Science.gov (United States)

    Masset, Patrick; Poinso, Jean-Yves; Poignet, Jean-Claude

    Water uptake of single salts and electrolytes were measured in industrial conditions (dry-room). The water uptake rate ϑ (g h -1 cm -2) was expressed with respect to the apparent area of contact of the salt with atmosphere of the dry room. The water uptake by potassium-based salts was very low. LiF and LiCl salts were found to behave similarly. For LiBr- and LiI-based salts and mixtures, we pointed out a linear relationship between the water uptake and the elapsed time. Water uptake by magnesium oxide reached a limit after 200 h. This work provides a set of data concerning the rate of water uptake by single salts, salt mixtures and magnesia used in thermal battery electrolytes.

  5. Inorganic phosphorus fertilizer ameliorates maize growth by reducing metal uptake, improving soil enzyme activity and microbial community structure.

    Science.gov (United States)

    Wu, Wencheng; Wu, Jiahui; Liu, Xiaowen; Chen, Xianbin; Wu, Yingxin; Yu, Shixiao

    2017-09-01

    Recently, several studies have showed that both organic and inorganic fertilizers are effective in immobilizing heavy metals at low cost, in comparison to other remediation strategies for heavy metal-contaminated farmlands. A pot trial was conducted in this study to examine the effects of inorganic P fertilizer and organic fertilizer, in single application or in combination, on growth of maize, heavy metal availabilities, enzyme activities, and microbial community structure in metal-contaminated soils from an electronic waste recycling region. Results showed that biomass of maize shoot and root from the inorganic P fertilizer treatments were respectively 17.8 and 10.0 folds higher than the un-amended treatments (CK), while the biomass in the organic fertilizer treatments was only comparable to the CK. In addition, there were decreases of 85.0% in Cd, 74.3% in Pb, 66.3% in Cu, and 91.9% in Zn concentrations in the roots of maize grown in inorganic P fertilizer amended soil. Consistently, urease and catalase activities in the inorganic P fertilizer amended soil were 3.3 and 2.0 times higher than the CK, whereas no enhancement was observed in the organic fertilizer amended soil. Moreover, microbial community structure was improved by the application of inorganic P fertilizer, but not by organic fertilizer; the beneficial microbial groups such as Kaistobacter and Koribacter were most frequently detected in the inorganic P fertilizer amended soil. The negligible effect from the organic fertilizer might be ascribed to the decreased pH value in soils. The results suggest that the application of inorganic P fertilizer (or in combination with organic fertilizer) might be a promising strategy for the remediation of heavy metals contaminated soils in electronic waste recycling region. Copyright © 2017. Published by Elsevier Inc.

  6. Bark water uptake promotes localized hydraulic recovery in coastal redwood crown

    Science.gov (United States)

    J. Mason Earles; Or Sperling; Lucas C. R. Silva; Andrew J. McElrone; Craig R. Brodersen; Malcolm P. North; Maciej A. Zwieniecki

    2015-01-01

    Coastal redwood (Sequoia sempervirens), the world’s tallest tree species, rehydrates leaves via foliar water uptake during fog/rain events. Here we examine if bark also permits water uptake in redwood branches, exploring potential flow mechanisms and biological significance. Using isotopic labelling and microCT imaging, we observed that water...

  7. Effect of water uptake on the fracture behavior of low-k organosilicate glass

    Science.gov (United States)

    Xiangyu Guo; Joseph E. Jakes; Samer Banna; Yoshio Nishi; J. Leon Shohet

    2014-01-01

    Water uptake in porous low-k dielectrics has become a significant challenge for both back-end-of-the-line integration and circuit reliability. This work examines the effects of water uptake on the fracture behavior of nanoporous low-k organosilicate glass. By using annealing dehydration and humidity conditioning, the roles of different water types...

  8. Magnetic Hybrid Nanosorbents for the Uptake of Paraquat from Water

    Directory of Open Access Journals (Sweden)

    Tiago Fernandes

    2017-03-01

    Full Text Available Although paraquat has been banned in European countries, this herbicide is still used all over the world, thanks to its low-cost, high-efficiency, and fast action. Because paraquat is highly toxic to humans and animals, there is interest in mitigating the consequences of its use, namely by implementing removal procedures capable of curbing its environmental and health risks. This research describes new magnetic nanosorbents composed of magnetite cores functionalized with bio-hybrid siliceous shells, that can be used to uptake paraquat from water using magnetically-assisted procedures. The biopolymers κ-carrageenan and starch were introduced into the siliceous shells, resulting in two hybrid materials, Fe3O4@SiO2/SiCRG and Fe3O4@SiO2/SiStarch, respectively, that exhibit a distinct surface chemistry. The Fe3O4@SiO2/SiCRG biosorbents displayed a superior paraquat removal performance, with a good fitting to the Langmuir and Toth isotherm models. The maximum adsorption capacity of paraquat for Fe3O4@SiO2/SiCRG biosorbents was 257 mg·g−1, which places this sorbent among the best systems for the removal of this herbicide from water. The interesting performance of the κ-carrageenan hybrid, along with its magnetic properties and good regeneration capacity, presents a very efficient way for the remediation of water contaminated with paraquat.

  9. Adaptation to high temperature mitigates the impact of water deficit during combined heat and drought stress in C3 sunflower and C4 maize varieties with contrasting drought tolerance.

    Science.gov (United States)

    Killi, Dilek; Bussotti, Filippo; Raschi, Antonio; Haworth, Matthew

    2017-02-01

    Heat and drought stress frequently occur together, however, their impact on plant growth and photosynthesis (P N ) is unclear. The frequency, duration and severity of heat and drought stress events are predicted to increase in the future, having severe implications for agricultural productivity and food security. To assess the impact on plant gas exchange, physiology and morphology we grew drought tolerant and sensitive varieties of C3 sunflower (Helianthus annuus) and C4 maize (Zea mays) under conditions of elevated temperature for 4 weeks prior to the imposition of water deficit. The negative impact of temperature on P N was most apparent in sunflower. The drought tolerant sunflower retained ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) activity under heat stress to a greater extent than its drought sensitive counterpart. Maize exhibited no varietal difference in response to increased temperature. In contrast to previous studies, where a sudden rise in temperature induced an increase in stomatal conductance (G s ), we observed no change or a reduction in G s with elevated temperature, which alongside lower leaf area mitigated the impact of drought at the higher temperature. The drought tolerant sunflower and maize varieties exhibited greater investment in root-systems, allowing greater uptake of the available soil water. Elevated temperatures associated with heat-waves will have profound negative impacts on crop growth in both sunflower and maize, but the deleterious effect on P N was less apparent in the drought tolerant sunflower and both maize varieties. As C4 plants generally exhibit water use efficiency (WUE) and resistance to heat stress, selection on the basis of tolerance to heat and drought stress would be more beneficial to the yields of C3 crops cultivated in drought prone semi-arid regions. © 2016 Scandinavian Plant Physiology Society.

  10. Simulation of root water uptake. II. Non-uniform transient water stress using different reduction functions

    NARCIS (Netherlands)

    Homaee, M.; Feddes, R.A.; Dirksen, C.

    2002-01-01

    The macroscopic root water uptake approach was used in the numerical simulation model HYSWASOR to test four different pressure head-dependent reduction functions. The input parameter values were obtained from the literature and derived from extensive measurements under controlled conditions in the

  11. Dual permeability soil water dynamics and water uptake by roots in irrigated potato fields

    DEFF Research Database (Denmark)

    Dolezal, Frantisek; Zumr, David; Vacek, Josef

    2007-01-01

    Water movement and uptake by roots in a drip-irrigated potato field was studied by combining field experiments, outputs of numerical simulations and summary results of an EU project (www.fertorganic.org). Detailed measurements of soil suction and weather conditions in the Bohemo-Moravian highland...

  12. Contrasting effects of biochar, compost and farm manure on alleviation of nickel toxicity in maize (Zea mays L.) in relation to plant growth, photosynthesis and metal uptake.

    Science.gov (United States)

    Rehman, Muhammad Zia-Ur; Rizwan, Muhammad; Ali, Shafaqat; Fatima, Nida; Yousaf, Balal; Naeem, Asif; Sabir, Muhammad; Ahmad, Hamaad Raza; Ok, Yong Sik

    2016-11-01

    Nickel (Ni) toxicity in agricultural crops is a widespread problem while little is known about the role of biochar (BC) and other organic amendments like farm manure (FM) from cattle farm and compost (Cmp) on its alleviation. A greenhouse experiment was conducted to evaluate the effects of BC, Cmp and FM on physiological and biochemical characteristics of maize (Zea mays L.) under Ni stress. Maize was grown in Ni spiked soil without and with two rates of the amendments (equivalent to 1% and 2% organic carbon, OC) applied separately to the soil. After harvest, plant height, root length, dry weight, chlorophyll contents, gas exchange characteristics and trace elements in plants were determined. In addition, post-harvest soil characteristics like pHs, ECe and bioavailable Ni were also determined. Compared to the control, all of the amendments increased plant height, root length, shoot and root dry weight with the maximum increase in all parameters by FM (2% OC) treatment. Similarly, total chlorophyll contents and gas exchange characteristics significantly increased with the application of amendments being maximum with FM (2% OC) application. Amendments significantly increased copper, zinc, manganese and iron concentrations and decreased Ni concentrations in the plants. The highest reduction in shoot Ni concentration was recorded with FM (2% OC) followed by BC (2% OC) being 73.2% and 61.1% lower compared to the control, respectively. The maximum increase in soil pH and decrease in AB-DTPA extractable Ni was recorded with BC (2% OC) followed by FM (2% OC). It is concluded that FM (2% OC) was the most effective in reducing Ni toxicity to plants by reducing Ni uptake while BC (2% OC) was the most effective in decreasing bioavailable Ni in the soil through increasing soil pH. However, long-term field studies are needed to evaluate the effects of these amendments in reducing Ni toxicity in plants. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Water deficit imposed by deficit irrigation at different plant growth stages of maize

    International Nuclear Information System (INIS)

    Calvache, M.; Reichardt, C.

    1995-01-01

    The purpose of this study was to identify specific growth stages of maize Crop, at which the plant is less sensitive to water stress so that irrigation can be omitted withhout significant decrease yield. The field experiment was conducted at a University experiment station, Tumbaco, Pichincha, Ecuador, during may - october 1993, on a sandy loam soil ( typic durustoll). Soil moisture was monitored with a neutron probe down to 0.70 m depth, before and 24 h after each irrigation. The actual evapotranspiration of the crop was estimated by the water - balance technique. Field water efficiency and crop water use efficiency were calculated by dividing actual grain yield by irrigation and by ETa, respectively. Nitrogen fertilizer use efficiency was calculated using N - 15 methodology in the 75 kg N/ ha treatment. From the yield data, it can be concluded that treatments which had irrigation deficit had lower yield than those that had suplementary irrigation. The flowering and yield formation stages were the most sensitive to moisture stress. Nitrogen fertilization significantly increased the grain yield. The crop water use effeciency was the lowest at the flowering and yield formation of the region, the treatments I1 and I7 had the same crop water use efficiency. The results of N - 15 labelled plots ( F1) showed that soil water deficiency significantly affects nitrogen was derived from fertilizer in treatments I3 and I7 and only 11 - 9% in the treatments I2 and I5 respectively. ( Author)

  14. Virtual water content of temperate cereals and maize: Present and potential future patterns

    Science.gov (United States)

    Fader, Marianela; Rost, Stefanie; Müller, Christoph; Bondeau, Alberte; Gerten, Dieter

    2010-04-01

    SummaryKnowledge of the virtual water content (VWC) of crops and especially its possible future developments is helpful for improvements in water productivity and water management, which are necessary at global scale due to rising demand for food, the necessity to ease present and future water scarcity, and the reduction of poverty. Using a dynamic global vegetation and water balance model (LPJmL), this study quantifies the VWC of two of the most important crop types worldwide, temperate cereals and maize, at high spatial resolution (0.5°). We analyzed present conditions (1999-2003) and also for the first time also for scenarios of future climate and increasing atmospheric CO 2 concentrations (2041-2070; HadCM3, ECHAM5 and CCSM3 climate models, A2 emissions scenario). VWC presently differs significantly among regions: highest values are common in large parts of Africa (>2 m 3 kg -1), and lowest values were found e.g. for Central Europe (Europe, South Africa, Argentina, Australia and South East Asia—are projected to become less water efficient (higher VWC) for at least one of the crop types. CO 2 fertilisation was simulated to generally reduce VWC, though realisation of this effect in the field will depend, for example, on the intensity of nutrient management in the future. The potentially adverse future changes in VWC found here pose a challenge to water management efforts and eventually global trade policies.

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

    Directory of Open Access Journals (Sweden)

    Hossain Sohrawardy

    2014-01-01

    Full Text Available The study was conducted as a pot experiment in the tropical glasshouse to evaluate the response of grain legumes (Phaseolus vulgaris, Vigna unguiculata, and Lablab purpureus in comparison to maize (Zea mays and estimate their potential and performance. Two experiments were established using completely randomized design. Physiological measurements (stomatal conductance, photosynthetic activities, and transpiration rates were measured using LCpro instrument. Scholander bomb was used for the measurement of plant cell water potential. Significant difference was observed in different plant species with increase of different water regimes. Among the legumes, L. purpureus showed better response in water stressed conditions. At the beginning, in dry watered treatment the photosynthetic rate was below 0 µmol m−2 s−1 and in fully watered condition it was 48 µmol m−2 s−1. In dry treatment, total dry weight was 10 g/pot and in fully watered condition it was near to 20 g/pot in P. vulgaris. The study concludes that water stress condition should be taken into consideration for such type of crop cultivation in arid and semiarid regions.

  16. Carbon dioxide mediates the response to temperature and water activity levels in Aspergillus flavus during infection of maize kernels

    Science.gov (United States)

    Aspergillus flavus is a saprophytic fungus that may colonize several important crops, including cotton, maize, peanuts and tree nuts. Concomitant with A. flavus colonization is its potential to secrete mycotoxins, of which the most prominent is aflatoxin. Temperature, water activity (aw) and carbon ...

  17. Dryland maize yields and water use efficiency in response to tillage/crop stubble and nutrient management practices in China

    NARCIS (Netherlands)

    Wang, X.B.; Dai, K.; Zhang, D.; Zhang, X.; Wang, Y.; Zhao, Q.; Cai, D.X.; Hoogmoed, W.B.; Oenema, O.

    2011-01-01

    Rainfed crop production in northern China is constrained by low and variable rainfall. This study explored the effects of tillage/crop residue and nutrient management practices on maize (Zea mays L.) yield, water use efficiency (WUE), and N agronomic use efficiency (NAE) at Shouyang Dryland Farming

  18. 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.

  19. Assessment of productivity and water use efficiency in three maize (zea mays L.) varieties in Kwabenya-Atomic area

    International Nuclear Information System (INIS)

    Frimpong, J. O.

    2010-06-01

    The production of rain-fed maize in the Kwabenya-Atomic area of the coastal savannah environment of Ghana is limited by low and erratic rainfall. Enhancing maize production in the area will require the use of maize varieties efficient in the use of soil moisture. The study was, therefore, conducted to evaluate three recently released maize varieties (Obatanpa, Mamaba, and Golden Crystal) for their efficiency in the use of soil moisture for total dry matter and grain production and consequently identify the maize varieties suitable for rain-fed production in the Kwabenya-Atomic area. Field experiments were conducted m 2008 during the major and minor cropping seasons at Kwabenya-Atomic area in Ghana using three maize varieties grown at a planting distance of 0.4 m within rows and 0.8 m between rows. The experimental design used was the randomised complete block design in four replicates. Plants were sampled every two weeks throughout the maize growing seasons. Access tubes installed in each sub-plot facilitated simultaneous moisture monitoring with the aid of a neutron probe (CPN (R) 503 Hydroprobe) in a 120 cm soil profile. The moisture content values were used for the estimation of actual evapotranspiration of the maize crop using the water balance approach. Grain yield (GY) and its associated water use efficiency (WUE GY ) were significantly different (P ≤ 0.05) among the maize varieties during the major cropping season with Mamaba producing the highest grain yield of 7250.0 kg ha -1 and WUE GY of 13.2 kg ha -1 mm -1 . For the minor cropping season, no significant difference was observed in grain yield, which ranged between 5800.0 and 7200.0 kg ha -1 , with Obatanpa producing the highest grain yield. No significant difference was observed in WUE GY during the minor cropping season which ranged between 14.6 and 19.1 kg ha -1 mm -1 with Obatanpa having the highest WUE GY . The maize genotype produced similar total dry matter (TDM) during each of the cropping

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

    Directory of Open Access Journals (Sweden)

    Nour Ali SAJEDI

    2010-09-01

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

  1. Efficiency of ammonium nitrate phosphates of varying water-soluble phosphorus content for rice and succeeding maize crop on contrasting soil types

    International Nuclear Information System (INIS)

    Bhujbal, B.M.; Mistry, K.B.; Chapke, V.G.; Mutatkar, V.K.

    1977-01-01

    Efficiency of ammonium nitrate phosphates (ANP) containing 30 and 50 percent of water-soluble phosphorus (W.S.P.) vis-a-vis that of entirely water-soluble monoammonium orthophosphate (MAP) for rice and succeeding maize crop on phosphate responsive laterite, red sandy loam (Chalka) and calcareous black soils was examined in greenhouse experiments. Data on dry matter yield, uptake of phosphorus, utilization of applied fertilizer, 'Effective Rate of Application' and 'Relative Efficiency percent' at flowering stage of rice indicated no significant differences between ammonium nitrate phosphate (30 percent and 50 percent water-soluble ohosphorus) and monoammonium orthophosphate (MAP) on laterits and natural red sandy loam soils. MAP was significantly superior to the two ANP fertilizers on calcareous black soil; no significant differences were observed between ANP (30 percent W.S.P.) and ANP (50 percent W.S.P.) on this soil. The succeeding maize crop grown up to flowering in the same pots indicated that the residual value of ANP (30 percent W.S.P.) was equal or superior to that of MAP on the laterits as well as calcareous black soil. No significant differences were detected between the residual values of the two water-solubility grades of ANP. Incubation under submerged conditions for periods upto 60 days showed that 0.5 M NaHCO 3 (pH 8.5) extractable phosphorus (plant-available phosphate) in the ANP (30 percent W.S.P.) treatment was, in general, equal to those in the MAP treatments in the laterite and red sandy loam but was significantly lower in the calcareous black soil. No marked differences were observed between the effects of the two ANP fertilizers. (author)

  2. Efficiency of ammonium nitrate phosphates of varying water-soluble phosphorus content for rice and succeeding maize crop on contrasting soil types. [/sup 32/P-labelled fertilizers

    Energy Technology Data Exchange (ETDEWEB)

    Bhujbal, B M; Mistry, K B [Bhabha Atomic Research Centre, Bombay (India). Biology and Agriculture Div.; Chapke, V G; Mutatkar, V K [Fertilizer Corp. of India Ltd., Bombay

    1977-09-01

    Efficiency of ammonium nitrate phosphates (ANP) containing 30 and 50 percent of water-soluble phosphorus (W.S.P.) vis-a-vis that of entirely water-soluble monoammonium orthophosphate (MAP) for rice and succeeding maize crop on phosphate responsive laterite, red sandy loam (Chalka) and calcareous black soils was examined in greenhouse experiments. Data on dry matter yield, uptake of phosphorus, utilization of applied fertilizer, 'Effective Rate of Application' and 'Relative Efficiency percent' at flowering stage of rice indicated no significant differences between ammonium nitrate phosphate (30 percent and 50 percent water-soluble ohosphorus) and monoammonium orthophosphate (MAP) on laterits and natural red sandy loam soils. MAP was significantly superior to the two ANP fertilizers on calcareous black soil; no significant differences were observed between ANP (30 percent W.S.P.) and ANP (50 percent W.S.P.) on this soil. The succeeding maize crop grown up to flowering in the same pots indicated that the residual value of ANP (30 percent W.S.P.) was equal or superior to that of MAP on the laterits as well as calcareous black soil. No significant differences were detected between the residual values of the two water-solubility grades of ANP. Incubation under submerged conditions for periods upto 60 days showed that 0.5 M NaHCO/sub 3/ (pH 8.5) extractable phosphorus (plant-available phosphate) in the ANP (30 percent W.S.P.) treatment was, in general, equal to those in the MAP treatments in the laterite and red sandy loam but was significantly lower in the calcareous black soil. No marked differences were observed between the effects of the two ANP fertilizers.

  3. Soil water capture trends over 50 years of single-cross maize (Zea mays L.) breeding in the US corn-belt.

    Science.gov (United States)

    Reyes, Andres; Messina, Carlos D; Hammer, Graeme L; Liu, Lu; van Oosterom, Erik; Lafitte, Renee; Cooper, Mark

    2015-12-01

    Breeders have successfully improved maize (Zea mays L.) grain yield for the conditions of the US corn-belt over the past 80 years, with the past 50 years utilizing single-cross hybrids. Long-term improvement for grain yield under water-limited conditions has also been reported. Grain yield under water-limited conditions depends on water use, water use efficiency, and harvest index. It has been hypothesized that long-term genetic gain for yield could be due, in part, to increased water capture from the soil. This hypothesis was tested using a set of elite single-cross hybrids that were released by DuPont Pioneer between 1963 and 2009. Eighteen hybrids were grown in the field during 2010 and 2011 growing seasons at Woodland, CA, USA. Crops grew predominantly on stored soil water and drought stress increased as the season progressed. Soil water content was measured to 300cm depth throughout the growing season. Significant water extraction occurred to a depth of 240-300cm and seasonal water use was calculated from the change in soil water over this rooting zone. Grain yield increased significantly with year of commercialization, but no such trend was observed for total water extraction. Therefore, the measured genetic gain for yield for the period represented by this set of hybrids must be related to either increased efficiency of water use or increased carbon partitioning to the grain, rather than increased soil water uptake. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  4. Chloroform and trichloroethylene uptake from water into human skin in vitro: Kinetics and risk implications

    International Nuclear Information System (INIS)

    Bogen, K.T.; Keating, G.A.; Vogel, J.S.

    1995-03-01

    A model recently proposed by the US Environmental Protection Agency (EPA) predicts that short-term dermal uptakes of organic environmental water contaminants are proportional to the square root of exposure time. The model appears to underestimate dermal uptake, based on very limited in vivo uptake data obtained primarily using human subjects. To further assess this model, we examined in vitro dermal uptake kinetics for aqueous organic chemicals using accelerator mass spectrometry (AMS). Specifically, we examined the kinetics of in vitro dermal uptake of 14 C-labeled chloroform and trichloroethylene from dilute (5-ppb) aqueous solutions using full-thickness human cadaver skin exposed for (≤1 hr)

  5. A Comparative Study on the Uptake and Toxicity of Nickel Added in the Form of Different Salts to Maize Seedlings

    Directory of Open Access Journals (Sweden)

    Jing Nie

    2015-11-01

    Full Text Available In soil ecotoxicological studies, a toxic metal is usually added in the form of either an inorganic or organic salt with relatively high solubility. Nitrate, chloride, acetate, or sulfate are commonly considered as valid options for that aim. However, recent studies have shown that different salts of the same metal at the same cationic concentration may exhibit different toxicities to plants and soil organisms. This information should be considered when selecting data to use for developing toxicological criteria for soil environment. A comparative study was carried out to evaluate the toxicity of five nickel (Ni salts: NiCl2, NiSO4, Ni(II-citrate, Ni(CH3COO2, and Ni(II-EDTA (ethylenediaminetetraacetate, on maize seedlings. The plant metrics used were plant height, shoot and root biomass, leaf soluble sugars and starch, and the Ni contents of the shoots and roots. The results indicated that when Ni was added to the soil, toxicity varied with the selected anionic partner with the following toxicity ranking NiSO4 < Ni(CH3COO2 < Ni(II-citrate < NiCl2 < Ni(II-EDTA. Taking the plant-height metric as an example, the effective concentrations for 50% inhibition (EC50 were 3148 mg·kg−1 for NiSO4, 1315 mg·kg−1 for NiCl2, and 89 mg·kg−1 for Ni(II-EDTA. Compared with the Ni in the other salts, that in Ni(II-EDTA was taken up the most efficiently by the maize roots and, thus, resulted in the greatest toxic effects on the plants. Nickel generally reduced leaf soluble sugars, which indicated an effect on plant carbohydrate metabolism. The outcome of the study demonstrates that different salts of the same metal have quite different ecotoxicities. Therefore, the anionic counterpart of a potentially toxic metal cation must be taken into account in the development of ecotoxicological criteria for evaluating the soil environment, and a preferred approach of leaching soil to reduce the anionic partner should also be considered.

  6. Plastic-Film Mulching for Enhanced Water-Use Efficiency and Economic Returns from Maize Fields in Semiarid China.

    Science.gov (United States)

    Zhang, Peng; Wei, Ting; Cai, Tie; Ali, Shahzad; Han, Qingfang; Ren, Xiaolong; Jia, Zhikuan

    2017-01-01

    Film mulch has gradually been popularized to increase water availability to crops for improving and stabilizing agricultural production in the semiarid areas of Northwest China. To find more sustainable and economic film mulch methods for alleviating drought stress in semiarid region, it is necessary to test optimum planting methods in same cultivation conditions. A field experiment was conducted during 2013 and 2014 to evaluate the effects of different plastic film mulch methods on soil water, soil temperature, water use efficiency (WUE), yield and revenue. The treatments included: (i) the control, conventional flat planting without plastic film mulch (CK); (ii) flat planting with maize rows (60 cm spacing) on plastic film mulch (70 cm wide); (iii) furrow planting of maize (60 cm spacing), separated by consecutive plastic film-mulched ridges (each 50 cm wide and 15 cm tall); (iv) furrow planting of maize (60 cm spacing), separated by alternating large and small plastic film-mulched ridges (large ridges: 70 cm wide and 15 cm tall, small ridges 50 cm wide and 10 cm tall); and (v) furrow-flat planting of maize (60 cm spacing) with a large plastic film-mulched ridge (60 cm wide and 15 cm tall) alternating with a flat without plastic film-mulched space (60 cm wide). Topsoil temperature (5-25 cm) was significantly ( p plastic film mulch than the control (CK), and resulted in greater soil water storage (0-200 cm) up to 40 days after planting. Maize grain yield and WUE were significantly ( p < 0.05) higher with the furrow planting methods (consecutive film-mulched ridges and alternating film-mulched ridges) than the check in both years. Maize yield was, on average, 29% ( p < 0.05) greater and 28% ( p < 0.05) greater with these furrow planting methods, while the average WUE increased by 22.8% ( p < 0.05) with consecutive film-mulched ridges and 21.1% ( p < 0.05) with alternating film-mulched ridges. The 2-year average net income increased by 1559, 528, and 350 Chinese Yuan

  7. Tillage and straw mulching impacts on grain yield and water use efficiency of spring maize in Northern Huang-Huai-Hai Valley

    Institute of Scientific and Technical Information of China (English)

    Zhiqiang Tao; Congfeng Li; Jingjing Li; Zaisong Ding; Jie Xu; Xuefang Sun; Peilu Zhou; Ming Zhao

    2015-01-01

    A two-year field experiment (2012–2013) was conducted to investigate the effects of two tillage methods and five maize straw mulching patterns on the yield, water consumption, and water use efficiency (WUE) of spring maize (Zea mays L.) in the northern Huang–Huai–Hai valley of China. Compared to rotary tillage, subsoil tillage resulted in decreases in water consumption by 6.3–7.8% and increases in maize yield by 644.5–673.9 kg ha−1, soil water content by 2.9–3.0%, and WUE by 12.7–15.2%. Chopped straw mulching led to higher yield, soil water content, and WUE as well as lower water consumption than prostrate whole straw mulching. Mulching with 50%chopped straw had the largest positive effects on maize yield, soil water content, and WUE among the five mulching treatments. Tillage had greater influence on maize yield than straw mulching, whereas straw mulching had greater influence on soil water content, water consumption, and WUE than tillage. These results suggest that 50%chopped straw mulching with subsoil tillage is beneficial in spring maize production aiming at high yield and high WUE in the Huang–Huai–Hai valley.

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

    Science.gov (United States)

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

    2018-03-01

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

  9. Reduced irrigation increases the water use efficiency and productivity of winter wheat-summer maize rotation on the North China Plain.

    Science.gov (United States)

    Wang, Yunqi; Zhang, Yinghua; Zhang, Rui; Li, Jinpeng; Zhang, Meng; Zhou, Shunli; Wang, Zhimin

    2018-03-15

    The groundwater table has fallen sharply over the last 30years on the North China Plain, resulting in a shortage of water for winter wheat irrigation. Reducing irrigation may be an important strategy to maintain agricultural sustainability in the region; however, few studies have evaluated the transition from conventional irrigation management practices to reduced irrigation management practices in the winter wheat-summer maize rotation system. Here, we compare the yield, water consumption, and water use efficiency of winter wheat-summer maize rotation under conventional irrigation and reduced irrigation on the North China Plain from 2012 to 2015. Reducing irrigation decreased the yield but increased the water use efficiency and significantly advanced the harvest date of winter wheat. As a result, the summer maize sowing date advanced significantly, and the flowering date subsequently advanced 2-8days, thus extending the summer maize grain-filling stage. Therefore, the yield and water use efficiency of summer maize were higher under reduced irrigation than conventional irrigation, which compensated for the winter wheat yield loss under reduced irrigation. In addition, under reduced irrigation from 2012 to 2015, the yield and water use efficiency advantage of the winter wheat-summer maize rotation ranged from 0.0 to 9.7% and from 4.1 to 14.7%, respectively, and water consumption and irrigated water decreased by 20-61mm and 150mm, respectively, compared to conventional irrigation. Overall, the reduced irrigation management practice involving no irrigation after sowing winter wheat, and sowing summer maize on June 7 produced the most favorable grain yield with superb water use efficiency in the winter wheat-summer maize rotation. This study indicates that reducing irrigation could be an efficient means to cope with water resource shortages while maintaining crop production sustainability on the North China Plain. Copyright © 2017. Published by Elsevier B.V.

  10. Impact of Different Agricultural Waste Biochars on Maize Biomass and Soil Water Content in a Brazilian Cerrado Arenosol

    Directory of Open Access Journals (Sweden)

    Alicia B. Speratti

    2017-07-01

    Full Text Available Arenosols in the Brazilian Cerrado are increasingly being used for agricultural production, particularly maize. These sandy soils are characterized by low soil organic matter, low available nutrients, and poor water-holding capacity. For this reason, adding biochar as a soil amendment could lead to improved water and nutrient retention. A greenhouse experiment was carried out using twelve biochars derived from four feedstocks (cotton husks, swine manure, eucalyptus sawmill residue, sugarcane filtercake pyrolized at 400, 500 and 600 °C and applied at 5% w/w. The biochars’ effect on maize biomass was examined, along with their contribution to soil physical properties including water retention, electrical conductivity (EC, and grain size distribution. After six weeks, maize plants in soils with eucalyptus and particularly filtercake biochar had higher biomass compared to those in soils with cotton and swine manure biochars. The latter’s low biomass was likely related to excessive salinity. In general, our biochars showed potential for increasing θ in sandy soils compared to the soil alone. Filtercake and eucalyptus biochars may improve soil aeration and water infiltration, while applying cotton and swine manure biochars at levels <5% to avoid high salinity could contribute to improved soil water retention in Cerrado Arenosols.

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

    Directory of Open Access Journals (Sweden)

    Ruixin Shao

    2015-09-01

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

  12. Influence of root-water-uptake parameterization on simulated heat transport in a structured forest soil

    Science.gov (United States)

    Votrubova, Jana; Vogel, Tomas; Dohnal, Michal; Dusek, Jaromir

    2015-04-01

    Coupled simulations of soil water flow and associated transport of substances have become a useful and increasingly popular tool of subsurface hydrology. Quality of such simulations is directly affected by correctness of its hydraulic part. When near-surface processes under vegetation cover are of interest, appropriate representation of the root water uptake becomes essential. Simulation study of coupled water and heat transport in soil profile under natural conditions was conducted. One-dimensional dual-continuum model (S1D code) with semi-separate flow domains representing the soil matrix and the network of preferential pathways was used. A simple root water uptake model based on water-potential-gradient (WPG) formulation was applied. As demonstrated before [1], the WPG formulation - capable of simulating both the compensatory root water uptake (in situations when reduced uptake from dry layers is compensated by increased uptake from wetter layers), and the root-mediated hydraulic redistribution of soil water - enables simulation of more natural soil moisture distribution throughout the root zone. The potential effect on heat transport in a soil profile is the subject of the present study. [1] Vogel T., M. Dohnal, J. Dusek, J. Votrubova, and M. Tesar. 2013. Macroscopic modeling of plant water uptake in a forest stand involving root-mediated soil-water redistribution. Vadose Zone Journal, 12, 10.2136/vzj2012.0154. The research was supported by the Czech Science Foundation Project No. 14-15201J.

  13. A maize introgression library reveals ample genetic variability for root architecture, water use efficiency and grain yield under different water regimes

    OpenAIRE

    Salvi, S.; Giuliani, S.; Cané, M.; Sciara, G.; Bovina, R.; Welcker, Claude; Cabrera Bosquet, Llorenç; Grau, Antonin; Tardieu, Francois; Meriggi, P.

    2015-01-01

    The genetic dissection of root system architecture (RSA) provides valuable opportunities towards a better understanding of its role in determining yield under different water regimes. To this end, a maize introgression library comprised of 75 BC5 lines derived from the cross between Gaspé Flint (an early line; donor parent) and B73 (an elite line; recurrent parent) were evaluated in two experiments conducted under well-watered and water-deficit conditions (WW and WD, respectively) in order to...

  14. Relationship between root water uptake and soil respiration: A modeling perspective

    Science.gov (United States)

    Teodosio, Bertrand; Pauwels, Valentijn R. N.; Loheide, Steven P.; Daly, Edoardo

    2017-08-01

    Soil moisture affects and is affected by root water uptake and at the same time drives soil CO2 dynamics. Selecting root water uptake formulations in models is important since this affects the estimation of actual transpiration and soil CO2 efflux. This study aims to compare different models combining the Richards equation for soil water flow to equations describing heat transfer and air-phase CO2 production and flow. A root water uptake model (RWC), accounting only for root water compensation by rescaling water uptake rates across the vertical profile, was compared to a model (XWP) estimating water uptake as a function of the difference between soil and root xylem water potential; the latter model can account for both compensation (XWPRWC) and hydraulic redistribution (XWPHR). Models were compared in a scenario with a shallow water table, where the formulation of root water uptake plays an important role in modeling daily patterns and magnitudes of transpiration rates and CO2 efflux. Model simulations for this scenario indicated up to 20% difference in the estimated water that transpired over 50 days and up to 14% difference in carbon emitted from the soil. The models showed reduction of transpiration rates associated with water stress affecting soil CO2 efflux, with magnitudes of soil CO2 efflux being larger for the XWPHR model in wet conditions and for the RWC model as the soil dried down. The study shows the importance of choosing root water uptake models not only for estimating transpiration but also for other processes controlled by soil water content.

  15. Influence of water relations and growth rate on plant element uptake and distribution

    Energy Technology Data Exchange (ETDEWEB)

    Greger, Maria [Stockholm Univ. (Sweden). Dept. of Botany

    2006-02-15

    Plant uptake of Ni, Sr, Mo, Cs, La, Th, Se, Cl and I was examined to determine how plant water relations and growth rate influence the uptake and distribution of these elements in the studied plants. The specific questions were how water uptake and growth rate influenced the uptake of various nuclides and how transpiration influenced translocation to the shoot. The knowledge gained will be used in future modelling of radionuclide leakage from nuclear waste deposits entering the ecosystem via plants. The plant studied was willow, Salix viminalis, a common plant in the areas suggested for waste disposal; since there can be clone variation, two different clones having different uptake properties for several other heavy metals were used. The plants were grown in nutrient solution and the experiments on 3-month-old plants were run for 3 days. Polyethylene glycol was added to the medium to decrease the water uptake rate, a fan was used to increase the transpiration rate, and different light intensities were used to produce different growth rates. Element concentration was analysed in roots and shoots. The results show that both the uptake and distribution of various elements are influenced in different ways and to various extents by water flow and plant growth rate, and that it is not possible from the chemical properties of these elements to know how they will react. However, in most cases increased growth rate diluted the concentration of the element in the tissue, reduced water uptake reduced the element uptake, while transpiration had no effect on the translocation of elements to the shoot. The clones did not differ in terms of either the uptake or translocation of the elements, except that I was not taken up and translocated to the shoot in one of the clones when the plant water flow or growth rate was too low. Not all of the elements were found in the plant in the same proportions as they had been added to the nutrient solution.

  16. Influence of water relations and growth rate on plant element uptake and distribution

    International Nuclear Information System (INIS)

    Greger, Maria

    2006-02-01

    Plant uptake of Ni, Sr, Mo, Cs, La, Th, Se, Cl and I was examined to determine how plant water relations and growth rate influence the uptake and distribution of these elements in the studied plants. The specific questions were how water uptake and growth rate influenced the uptake of various nuclides and how transpiration influenced translocation to the shoot. The knowledge gained will be used in future modelling of radionuclide leakage from nuclear waste deposits entering the ecosystem via plants. The plant studied was willow, Salix viminalis, a common plant in the areas suggested for waste disposal; since there can be clone variation, two different clones having different uptake properties for several other heavy metals were used. The plants were grown in nutrient solution and the experiments on 3-month-old plants were run for 3 days. Polyethylene glycol was added to the medium to decrease the water uptake rate, a fan was used to increase the transpiration rate, and different light intensities were used to produce different growth rates. Element concentration was analysed in roots and shoots. The results show that both the uptake and distribution of various elements are influenced in different ways and to various extents by water flow and plant growth rate, and that it is not possible from the chemical properties of these elements to know how they will react. However, in most cases increased growth rate diluted the concentration of the element in the tissue, reduced water uptake reduced the element uptake, while transpiration had no effect on the translocation of elements to the shoot. The clones did not differ in terms of either the uptake or translocation of the elements, except that I was not taken up and translocated to the shoot in one of the clones when the plant water flow or growth rate was too low. Not all of the elements were found in the plant in the same proportions as they had been added to the nutrient solution

  17. Carbon Dioxide Mediates the Response to Temperature and Water Activity Levels in Aspergillus flavus during Infection of Maize Kernels

    Directory of Open Access Journals (Sweden)

    Matthew K. Gilbert

    2017-12-01

    Full Text Available Aspergillus flavus is a saprophytic fungus that may colonize several important crops, including cotton, maize, peanuts and tree nuts. Concomitant with A. flavus colonization is its potential to secrete mycotoxins, of which the most prominent is aflatoxin. Temperature, water activity (aw and carbon dioxide (CO2 are three environmental factors shown to influence the fungus-plant interaction, which are predicted to undergo significant changes in the next century. In this study, we used RNA sequencing to better understand the transcriptomic response of the fungus to aw, temperature, and elevated CO2 levels. We demonstrate that aflatoxin (AFB1 production on maize grain was altered by water availability, temperature and CO2. RNA-Sequencing data indicated that several genes, and in particular those involved in the biosynthesis of secondary metabolites, exhibit different responses to water availability or temperature stress depending on the atmospheric CO2 content. Other gene categories affected by CO2 levels alone (350 ppm vs. 1000 ppm at 30 °C/0.99 aw, included amino acid metabolism and folate biosynthesis. Finally, we identified two gene networks significantly influenced by changes in CO2 levels that contain several genes related to cellular replication and transcription. These results demonstrate that changes in atmospheric CO2 under climate change scenarios greatly influences the response of A. flavus to water and temperature when colonizing maize grain.

  18. Soil mulching significantly enhances yields and water and nitrogen use efficiencies of maize and wheat: a meta-analysis

    Science.gov (United States)

    Qin, Wei; Hu, Chunsheng; Oenema, Oene

    2015-11-01

    Global crop yields are limited by water and nutrient availability. Soil mulching (with plastic or straw) reduces evaporation, modifies soil temperature and thereby affects crop yields. Reported effects of mulching are sometimes contradictory, likely due to differences in climatic conditions, soil characteristics, crop species, and also water and nitrogen (N) input levels. Here we report on a meta-analysis of the effects of mulching on wheat and maize, using 1310 yield observations from 74 studies conducted in 19 countries. Our results indicate that mulching significantly increased yields, WUE (yield per unit water) and NUE (yield per unit N) by up to 60%, compared with no-mulching. Effects were larger for maize than wheat, and larger for plastic mulching than straw mulching. Interestingly, plastic mulching performed better at relatively low temperature while straw mulching showed the opposite trend. Effects of mulching also tended to decrease with increasing water input. Mulching effects were not related to soil organic matter content. In conclusion, soil mulching can significantly increase maize and wheat yields, WUE and NUE, and thereby may contribute to closing the yield gap between attainable and actual yields, especially in dryland and low nutrient input agriculture. The management of soil mulching requires site-specific knowledge.

  19. Detecting and monitoring water stress states in maize crops using spectral ratios obtained in the photosynthetic domain

    Science.gov (United States)

    Baranoski, Gladimir V. G.; Van Leeuwen, Spencer R.

    2017-07-01

    The reliable detection and monitoring of changes in the water status of crops composed of plants like maize, a highly adaptable C4 species in large demand for both food and biofuel production, are longstanding remote sensing goals. Existing procedures employed to achieve these goals rely predominantly on the spectral signatures of plant leaves in the infrared domain where the light absorption within the foliar tissues is dominated by water. It has been suggested that such procedures could be implemented using subsurface reflectance to transmittance ratios obtained in the visible (photosynthetic) domain with the assistance of polarization devices. However, the experiments leading to this proposition were performed on detached maize leaves, which were not influenced by the whole (living) plant's adaptation mechanisms to water stress. In this work, we employ predictive simulations of light-leaf interactions in the photosynthetic domain to demonstrate that the living specimens' physiological responses to dehydration stress should be taken into account in this context. Our findings also indicate that a reflectance to transmittance ratio obtained in the photosynthetic domain at a lower angle of incidence without the use of polarization devices may represent a cost-effective alternative for the assessment of water stress states in maize crops.

  20. Soil mulching significantly enhances yields and water and nitrogen use efficiencies of maize and wheat: a meta-analysis.

    Science.gov (United States)

    Qin, Wei; Hu, Chunsheng; Oenema, Oene

    2015-11-20

    Global crop yields are limited by water and nutrient availability. Soil mulching (with plastic or straw) reduces evaporation, modifies soil temperature and thereby affects crop yields. Reported effects of mulching are sometimes contradictory, likely due to differences in climatic conditions, soil characteristics, crop species, and also water and nitrogen (N) input levels. Here we report on a meta-analysis of the effects of mulching on wheat and maize, using 1310 yield observations from 74 studies conducted in 19 countries. Our results indicate that mulching significantly increased yields, WUE (yield per unit water) and NUE (yield per unit N) by up to 60%, compared with no-mulching. Effects were larger for maize than wheat, and larger for plastic mulching than straw mulching. Interestingly, plastic mulching performed better at relatively low temperature while straw mulching showed the opposite trend. Effects of mulching also tended to decrease with increasing water input. Mulching effects were not related to soil organic matter content. In conclusion, soil mulching can significantly increase maize and wheat yields, WUE and NUE, and thereby may contribute to closing the yield gap between attainable and actual yields, especially in dryland and low nutrient input agriculture. The management of soil mulching requires site-specific knowledge.

  1. Foliar water uptake of Tamarix ramosissima from an atmosphere of high humidity.

    Science.gov (United States)

    Li, Shuang; Xiao, Hong-lang; Zhao, Liang; Zhou, Mao-Xian; Wang, Fang

    2014-01-01

    Many species have been found to be capable of foliar water uptake, but little research has focused on this in desert plants. Tamarix ramosissima was investigated to determine whether its leaves can directly absorb water from high humidity atmosphere and, if they can, to understand the magnitude and importance of foliar water uptake. Various techniques were adopted to demonstrate foliar water uptake under submergence or high atmospheric humidity. The mean increase in leaf water content after submergence was 29.38% and 20.93% for mature and tender leaves, respectively. In the chamber experiment, obvious reverse sap flow occurred when relative humidity (RH) was persistently above 90%. Reverse flow was recorded first in twigs, then in branches and stems. For the stem, the percentage of negative sap flow rate accounting for the maximum value of sap flow reached 10.71%, and its amount accounted for 7.54% of diurnal sap flow. Small rainfall can not only compensate water loss of plant by foliar uptake, but also suppress transpiration. Foliar uptake can appear in the daytime under certain rainfall events. High atmospheric humidity is beneficial for enhancing the water status of plants. Foliar uptake should be an important strategy of water acquisition for desert plants.

  2. Foliar Water Uptake of Tamarix ramosissima from an Atmosphere of High Humidity

    Directory of Open Access Journals (Sweden)

    Shuang Li

    2014-01-01

    Full Text Available Many species have been found to be capable of foliar water uptake, but little research has focused on this in desert plants. Tamarix ramosissima was investigated to determine whether its leaves can directly absorb water from high humidity atmosphere and, if they can, to understand the magnitude and importance of foliar water uptake. Various techniques were adopted to demonstrate foliar water uptake under submergence or high atmospheric humidity. The mean increase in leaf water content after submergence was 29.38% and 20.93% for mature and tender leaves, respectively. In the chamber experiment, obvious reverse sap flow occurred when relative humidity (RH was persistently above 90%. Reverse flow was recorded first in twigs, then in branches and stems. For the stem, the percentage of negative sap flow rate accounting for the maximum value of sap flow reached 10.71%, and its amount accounted for 7.54% of diurnal sap flow. Small rainfall can not only compensate water loss of plant by foliar uptake, but also suppress transpiration. Foliar uptake can appear in the daytime under certain rainfall events. High atmospheric humidity is beneficial for enhancing the water status of plants. Foliar uptake should be an important strategy of water acquisition for desert plants.

  3. Spatiotemporal Correlations between Water Footprint and Agricultural Inputs: A Case Study of Maize Production in Northeast China

    Directory of Open Access Journals (Sweden)

    Peili Duan

    2015-07-01

    Full Text Available To effectively manage water resources in agricultural production, it is necessary to understand the spatiotemporal variation of the water footprint (WF and the influences of agricultural inputs. Employing spatial autocorrelation analysis and a geographically weighted regression (GWR model, we explored the spatial variations of the WF and their relationships with agricultural inputs from 1998 to 2012 in Northeast China. The results indicated that: (1 the spatial distribution of WFs for the 36 major maize production prefectures was heterogeneous in Northeast China; (2 a cluster of high WFs was found in southeast Liaoning Province, while a cluster of low WFs was found in central Jilin Province, and (3 spatial and temporal differentiation in the correlations between the WF of maize production and agricultural inputs existed according to the GWR model. These correlations increased over time. Our results suggested that localized strategies for reducing the WF should be formulated based on specific relationships between the WF and agricultural inputs.

  4. Relationship between Water and Carbon Utilization under Different Straw Mulching and Plant Density of Summer Maize in North China Plain

    Science.gov (United States)

    Liu, Quanru; Du, Shoujian; Yin, Honglian; Wang, Juan

    2018-03-01

    To explore the relationship between water and carbon utilization and key factors to keep high water use efficiency (WUE), a 2-yr experiment was conduct by covering 0 and 0.6 kg m-2 straw to the surface of soil with plant densities of 1.0 × 105, 7.5 × 104, and 5.5 × 104 plants ha-1 in North China Plain during summer maize growing seasons of the 2012 and 2013. Results showed that straw mulching not only increased grain yield (GY), WUE, and carbon efficient ratio (CER) but also inhibited CO2 emission significantly. WUE positively correlated with CER, GY and negative correlated with evapotranspiration (ET) and CO2 emission. CER had the larger direct effect on WUE compared with ET and CO2 emission. The results indicate that straw mulching management in summer maize growing seasons could make sense for inhibiting CO2 emission.

  5. Improving yield and water productivity of maize grown under deficit-irrigated in dry area conditions

    Directory of Open Access Journals (Sweden)

    Mohamed H. Abd el-wahed

    2015-10-01

    Full Text Available Scarcity of water is the most severe constraint for development of maize in arid and semi-arid areas. Based on the actual crop need, the irrigation management has to be improved so that the water supply to the crop can be reduced while still achieving high yield. Therefore, the current study has been organized to evaluate the effects of deficit sprinkler irrigation (DSI and farmyard manure (FYM on Grain yield (GY and crop water productivity (CWP of corn, a 2-year experiment was conducted in arid region of Libya. The DSI treatments were (I100 = 100%, I85 = 85% or I70 = 70% of the crop evapotranspiration. FYM treatments were (0, 10 ton ha−1 spread either on the soil surface, incorporated with surface or subsurface layer (FYM10s, FYM10m or FYM10ss, respectively and 20 ton ha−1 spread as before (FYM20s, FYM20m or FYM20ss, respectively. Results indicated that the highest values of grain yield (GY were obtained from I100 treatment, while the lowest were observed in I70. FYM20ss enhanced GY than other FYM treatments in both seasons. The highest GY and CWP were recorded with I100 and received FYM20ss. It could be considered as a suitable under arid environmental conditions and similar regions, the treatment (I100 × FYM20ss is the most suitable for producing high GY and CWP. Under limited irrigation water, application of (I85 ×FYM20ss treatment was found to be favorable to save 15% of the applied irrigation water, at the time in which produced the same GY.

  6. Effect of different phosphorus fertilizer rates on N-uptake, N-efficiency and zea maize yield in irrigated soils

    International Nuclear Information System (INIS)

    Khalifa, Kh.

    1993-01-01

    Effect of different rates of P fertilizer on N-uptake, N-efficiency and zea mays (C.V.Lg 11) were studied by use of 15 N technique. The main objectives of this study were to study effect of different level of P on N-utilization and determine the interaction between P and N on zea mays yield, and the efficiency of N-fertilizer during different stages of plant growth. The field experiment was conducted for two years 1985 and 1986. The treatments were 0, 80, 160 Kg N, as urea Co( 15 NH 2 ) 2 and 0, 40, 80, 160 Kg P 2 O 5 as triplsuperphophate. The experiment design was randomized block of four replicates for each treatment. Yield (grain and dry matter), utilization of urea, N-uptake, total N, N-yield, Ndff%, NDF% and A-values were determined. All results indicate that zea mays responds to the addition of nitrogen and the yield increases with the increase of added nitrogen. The highest yield was for N 2 (160 Kg) level during two seasons. Also zea mays responds clearly to phosphorus especially at stages 1 and 2, where dry matter yield increases with the increase of phosphorus rate. The highest yield was for P 3 (160 Kg) rate. While in grain stage the response was for rate P 1 (40 Kg) and P 2 (80 Kg) in comparison with control. However P 1 , rate was dominant over P 2 and P 3 . The effect of P 2 rate on grain yield was very little in comparison with P 1 , while P 3 decreases the grain yield during two seasons in comparison with control. There is an effect of N and P when added both or separately. There is also effect for interaction between them on the yield (grain and dry matter). Generally, from the previous data we can conclude that the rate 160 Kg N/ha and 40 Kg P 2 O 5 /ha were optimum rate for zea mays fertilization in Deir-Ezzor (Syria) and similar areas for grain yield. (author). 17 refs., 6 tabs

  7. How yield relates to ash content, Delta 13C and Delta 18O in maize grown under different water regimes.

    Science.gov (United States)

    Cabrera-Bosquet, Llorenç; Sánchez, Ciro; Araus, José Luis

    2009-11-01

    Stable isotopes have proved a valuable phenotyping tool when breeding for yield potential and drought adaptation; however, the cost and technical skills involved in isotope analysis limit its large-scale application in breeding programmes. This is particularly so for Delta(18)O despite the potential relevance of this trait in C(4) crops. The accumulation of minerals (measured as ash content) has been proposed as an inexpensive way to evaluate drought adaptation and yield in C(3) cereals, but little is known of the usefulness of this measure in C(4) cereals such as maize (Zea mays). The present study investigates how yield relates to ash content, Delta(13)C and Delta(18)O, and evaluates the use of ash content as an alternative or complementary criterion to stable isotopes in assessing yield potential and drought resistance in maize. A set of tropical maize hybrids developed by CIMMYT were subjected to different water availabilities, in order to induce water stress during the reproductive stages under field conditions. Ash content and Delta(13)C were determined in leaves and kernels. In addition, Delta(18)O was measured in kernels. Water regime significantly affected yield, ash content and stable isotopes. The results revealed a close relationship between ash content in leaves and the traits informing about plant water status. Ash content in kernels appeared to reflect differences in sink-source balance. Genotypic variation in grain yield was mainly explained by the combination of ash content and Delta(18)O, whilst Delta(13)C did not explain a significant percentage of such variation. Ash content in leaves and kernels proved a useful alternative or complementary criterion to Delta(18)O in kernels for assessing yield performance in maize grown under drought conditions.

  8. Effects of No-tillage Combined with Reused Plastic Film Mulching on Maize Yield and Irrigation Water Productivity

    OpenAIRE

    SU Yong-zhong; ZHANG Ke; LIU Ting-na; WANG Ting

    2016-01-01

    A field experiment was conducted to determine the effects of reused plastic film mulching and no-tillage on maize yield and irriga-tion water productivity(IWP) in the marginal oasis in the middle of Hexi Corridor region of northwestern China. The aim is to provide an alternative tillage and cultivation pattern for reducing plastic film pollution, saving cost and increasing income, and improving resource use efficiency. The field experiment was carried out in three soils with different texture...

  9. Effects of farmers' practices of fertilizer application and land use types on subsequent maize yield and nutrient uptake in central Benin

    NARCIS (Netherlands)

    Saidou, A.; Kossou, D.; Acakpo, K.; Richards, P.; Kuyper, T.W.

    2012-01-01

    Four on-farm experiments in central Benin examined whether land-use succession and fertilizer treatments for prior cotton would sustain subsequent maize crop yields and achieve balanced plant nutrition. Treatments consisted of three prior land use successions, i.e. before planting maize (egusi

  10. Warmer temperatures reduce net carbon uptake, but not water use, in a mature southern Appalachian forest

    Science.gov (United States)

    Increasing air temperature is expected to extend growing season length in temperate, broadleaf forests, leading to potential increases in evapotranspiration and net carbon uptake. However, other key processes affecting water and carbon cycles are also highly temperature-dependent...

  11. Plant aquaporins: new perspectives on water and nutrient uptake in saline environment.

    Science.gov (United States)

    del Martínez-Ballesta, M C; Silva, C; López-Berenguer, C; Cabañero, F J; Carvajal, M

    2006-09-01

    The mechanisms of salt stress and tolerance have been targets for genetic engineering, focusing on ion transport and compartmentation, synthesis of compatible solutes (osmolytes and osmoprotectants) and oxidative protection. In this review, we consider the integrated response to salinity with respect to water uptake, involving aquaporin functionality. Therefore, we have concentrated on how salinity can be alleviated, in part, if a perfect knowledge of water uptake and transport for each particular crop and set of conditions is available.

  12. Uptake of different species of iodine by water spinach and its effect to growth.

    Science.gov (United States)

    Weng, Huan-Xin; Yan, Ai-Lan; Hong, Chun-Lai; Xie, Lin-Li; Qin, Ya-Chao; Cheng, Charles Q

    2008-08-01

    A hydroponic experiment has been carried out to study the influence of iodine species [iodide (I(-)), iodate (IO(-)(3)), and iodoacetic acid (CH(2)ICOO(-))] and concentrations on iodine uptake by water spinach. Results show that low levels of iodine in the nutrient solution can effectively stimulate the growth of biomass of water spinach. When iodine levels in the nutrient solution are from 0 to 1.0 mg/l, increases in iodine levels can linearly augment iodine uptake rate by the leafy vegetables from all three species of iodine, and the uptake effects are in the following order: CH(2)ICOO(-) >I(-)>IO(-)(3). In addition, linear correlation was observed between iodine content in the roots and shoots of water spinach, and their proportion is 1:1. By uptake of I(-), vitamin C (Vit C) content in water spinach increased, whereas uptake of IO(-)(3) and CH(2)ICOO(-) decreased water spinach Vit C content. Furthermore, through uptake of I(-) and IO(-)(3). The nitrate content in water spinach was increased by different degrees.

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

    Science.gov (United States)

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

    2018-05-01

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

  14. Modeling nitrate leaching and optimizing water and nitrogen management under irrigated maize in desert oases in Northwestern China.

    Science.gov (United States)

    Hu, Kelin; Li, Yong; Chen, Weiping; Chen, Deli; Wei, Yongping; Edis, Robert; Li, Baoguo; Huang, Yuanfang; Zhang, Yuanpei

    2010-01-01

    Understanding water and N transport through the soil profile is important for efficient irrigation and nutrient management to minimize nitrate leaching to the groundwater, and to promote agricultural sustainable development in desert oases. In this study, a process-based water and nitrogen management model (WNMM) was used to simulate soil water movement, nitrate transport, and crop growth (maize [Zea mays L.]) under desert oasis conditions in northwestern China. The model was calibrated and validated with a field experiment. The model simulation results showed that about 35% of total water input and 58% of the total N input were leached to <1.8 m depth under traditional management practice. Excessive irrigation and N fertilizer application, high nitrate concentration in the irrigation water, together with the sandy soil texture, resulted in large nitrate leaching. Nitrate leaching was significantly reduced under the improved management practice suggested by farm extension personnel; however, the water and nitrate inputs still far exceeded the crop requirements. More than 1700 scenarios combining various types of irrigation and fertilizer practices were simulated. Quantitative analysis was conducted to obtain the best management practices (BMPs) with simultaneous consideration of crop yield, water use efficiency, fertilizer N use efficiency, and nitrate leaching. The results indicated that the BMPs under the specific desert oasis conditions are to irrigate the maize with 600 mm of water in eight times with a single fertilizer application at a rate of 75 kg N ha(-1).

  15. Neonicotinoid insecticide residues in surface water and soil associated with commercial maize (corn fields in southwestern Ontario.

    Directory of Open Access Journals (Sweden)

    Arthur Schaafsma

    Full Text Available Neonicotinoid insecticides have come under scrutiny for their potential unintended effects on non-target organisms, particularly pollinators in agro-ecosystems. As part of a larger study of neonicotinoid residues associated with maize (corn production, 76 water samples within or around the perimeter of 18 commercial maize fields and neighbouring apiaries were collected in 5 maize-producing counties of southwestern Ontario. Residues of clothianidin (mean = 2.28, max. = 43.60 ng/mL and thiamethoxam (mean = 1.12, max. = 16.50 ng/mL were detected in 100 and 98.7% of the water samples tested, respectively. The concentration of total neonicotinoid residues in water within maize fields increased six-fold during the first five weeks after planting, and returned to pre-plant levels seven weeks after planting. However, concentrations in water sampled from outside the fields were similar throughout the sampling period. Soil samples from the top 5 cm of the soil profile were also collected in these fields before and immediately following planting. The mean total neonicotinoid residue was 4.02 (range 0.07 to 20.30 ng/g, for samples taken before planting, and 9.94 (range 0.53 to 38.98 ng/g, for those taken immediately after planting. Two soil samples collected from within an conservation area contained detectable (0.03 and 0.11 ng/g concentrations of clothianidin. Of three drifted snow samples taken, the drift stratum containing the most wind-scoured soil had 0.16 and 0.20 ng/mL mainly clothianidin in the melted snow. The concentration was at the limit of detection (0.02 ng/mL taken across the entire vertical profile. With the exception of one sample, water samples tested had concentrations below those reported to have acute, chronic or sublethal effects to honey bees. Our results suggest that neonicotinoids may move off-target by wind erosion of contaminated soil. These results are informative to risk assessment models for other non-target species in maize

  16. Neonicotinoid Insecticide Residues in Surface Water and Soil Associated with Commercial Maize (Corn) Fields in Southwestern Ontario

    Science.gov (United States)

    Schaafsma, Arthur; Limay-Rios, Victor; Baute, Tracey; Smith, Jocelyn; Xue, Yingen

    2015-01-01

    Neonicotinoid insecticides have come under scrutiny for their potential unintended effects on non-target organisms, particularly pollinators in agro-ecosystems. As part of a larger study of neonicotinoid residues associated with maize (corn) production, 76 water samples within or around the perimeter of 18 commercial maize fields and neighbouring apiaries were collected in 5 maize-producing counties of southwestern Ontario. Residues of clothianidin (mean = 2.28, max. = 43.60 ng/mL) and thiamethoxam (mean = 1.12, max. = 16.50 ng/mL) were detected in 100 and 98.7% of the water samples tested, respectively. The concentration of total neonicotinoid residues in water within maize fields increased six-fold during the first five weeks after planting, and returned to pre-plant levels seven weeks after planting. However, concentrations in water sampled from outside the fields were similar throughout the sampling period. Soil samples from the top 5 cm of the soil profile were also collected in these fields before and immediately following planting. The mean total neonicotinoid residue was 4.02 (range 0.07 to 20.30) ng/g, for samples taken before planting, and 9.94 (range 0.53 to 38.98) ng/g, for those taken immediately after planting. Two soil samples collected from within an conservation area contained detectable (0.03 and 0.11 ng/g) concentrations of clothianidin. Of three drifted snow samples taken, the drift stratum containing the most wind-scoured soil had 0.16 and 0.20 ng/mL mainly clothianidin in the melted snow. The concentration was at the limit of detection (0.02 ng/mL) taken across the entire vertical profile. With the exception of one sample, water samples tested had concentrations below those reported to have acute, chronic or sublethal effects to honey bees. Our results suggest that neonicotinoids may move off-target by wind erosion of contaminated soil. These results are informative to risk assessment models for other non-target species in maize agro

  17. Response of water deficit regime and soil amelioration on evapotranspiration loss and water use efficiency of maize ( Zea mays l.) in subtropical northeastern Himalayas

    Science.gov (United States)

    Marwein, M. A.; Choudhury, B. U.; Chakraborty, D.; Kumar, M.; Das, A.; Rajkhowa, D. J.

    2017-05-01

    Rainfed maize production in the hilly ecosystem of Northeastern Himalayas often suffers from moisture and soil acidity induced abiotic stresses. The present study measured evapotranspiration loss (ETc) of maize crop under controlled condition (pot experiment) of water deficit (W25-25 % and W50-50 % of field capacity soil moistures) and well watered (W100 = 100 % of field capacity (FC)) regimes in strong acid soils (pH = 4.3) of the Northeastern Himalayan Region of India. The response of soil ameliorants (lime) and phosphorus (P) nutrition under differential water regimes on ETc losses and water use efficiency was also studied. The measured seasonal ETc loss varied from 124.3 to 270.9 mm across treatment combinations. Imposition of water deficit stress resulted in significant ( p < 0.05) reduction (by 33-50 %) of seasonal ETc losses but was at the cost of delay in tasseling to silking, 47-65 % reduction in dry matter accumulation (DMA), 12-22 days shortening of grain formation period, and complete kernel abortion. Liming @ 4 t ha-1 significantly ( p < 0.05) increased ETc losses and DMA across water regimes but the magnitude of increase was higher in severely water deficit (W25) regime. Unlike lime, P nutrition improved DMA only in well-watered regimes (W100) while seasonal ETc loss was unaffected. Vegetative stage (tillering to tasseling) contributed the maximum ETc losses while weekly crop ETc loss was estimated highest during 11th-14th week after sowing (coincided with blistering stage) and then declined. Water use efficiency estimated from dry matter produced per unit ETc losses and irrigation water used varied from 4.33 to 9.43 g dry matter kg-1 water and 4.21 to 8.56 g dry matter kg-1, respectively. Among the input factors (water, P, and lime), water regime most strongly influenced the ETc loss, growth duration, grain formation, and water use efficiency of maize.

  18. Activated carbon from maize tassels and polymer composites for water decontamination

    OpenAIRE

    2014-01-01

    Ph.D. (Chemistry) This study presents work on the preparation, characterisation and application of agricultural waste residue, maize tassel in the production of activated carbon (AC) using both physical and chemical methods of activation in their production. The activated carbon produced from maize tassel (MTAC) or steam-produced activated carbon (STAC) were later added as a filler – together with beta-cyclodextrin (β-CD), and raw tassel (RT) – in the production of polyurethane composite a...

  19. Water uptake by fresh Indonesian peat burning particles is limited by water-soluble organic matter

    Science.gov (United States)

    Chen, Jing; Hapsari Budisulistiorini, Sri; Itoh, Masayuki; Lee, Wen-Chien; Miyakawa, Takuma; Komazaki, Yuichi; Qing Yang, Liu Dong; Kuwata, Mikinori

    2017-09-01

    The relationship between hygroscopic properties and chemical characteristics of Indonesian biomass burning (BB) particles, which are dominantly generated from peatland fires, was investigated using a humidified tandem differential mobility analyzer. In addition to peat, acacia (a popular species at plantation) and fern (a pioneering species after disturbance by fire) were used for experiments. Fresh Indonesian peat burning particles are almost non-hygroscopic (mean hygroscopicity parameter, κ octanol-water partitioning method. κ values for the water extracts are high, especially for peat burning particles (A0 (a whole part of the water-soluble fraction): κ = 0.18, A1 (highly water-soluble fraction): κ = 0.30). This result stresses the importance of both the WSOC fraction and κ of the water-soluble fraction in determining the hygroscopicity of organic aerosol particles. Values of κ correlate positively (R = 0.89) with the fraction of m/z 44 ion signal quantified using a mass spectrometric technique, demonstrating the importance of highly oxygenated organic compounds to the water uptake by Indonesian BB particles. These results provide an experimentally validated reference for hygroscopicity of organics-dominated particles, thus contributing to more accurate estimation of environmental and climatic impacts driven by Indonesian BB particles on both regional and global scales.

  20. Principles of root water uptake, soil salinity and crop yield for optimizing irrigation management

    International Nuclear Information System (INIS)

    Dirksen, C.

    1983-01-01

    The paper reviews the principles of water and salt transport, root water uptake, crop salt tolerance, water quality, and irrigation methods which should be considered in optimizing irrigation management for sustained, viable agriculture with protection of the quality of land and water resources. In particular, the advantages of high-frequency irrigation at small leaching fractions with closed systems are discussed, for which uptake-weighted mean salinity is expected to correlate best with crop yields. Optimization of irrigation management depends on the scale considered. Non-technical problems which are often much harder to solve than technical problems, may well be most favourable for new projects in developing countries. (author)

  1. Yield and water use efficiencies of maize and cowpea as affected by tillage and cropping systems in semi-arid Eastern Kenya

    International Nuclear Information System (INIS)

    Miriti, M.J; Kironchi, G; Gachene, K.K.C; Esilaba, O.A.; Mwangi, M.D; Heng, K.L

    2012-01-01

    Soil water conservation through tillage is widely accepted as one of the ways of improving crop yields in rainfed agriculture. Field experiments were conducted between 2007 and 2009 to evaluate the effects of conservation tillage on the yields and crop water use efficiency of maize (Zea mays L.) and cowpea (Vigna unguiculata L.) in eastern Kenya. Experimental treatments were a combination of three tillage practices and four cropping systems. Tillage practices were tied-ridges, subsoiling-ripping and ox-ploughing. The cropping systems were single crop maize, single crop cowpea, intercropped maize.cowpea and single crop maize with manure. The treatments were arranged in split plots with tillage practices as the main plots and cropping systems as the sub-plots in a Randomized Complete Block Design (RCBD). The results showed that tied-ridge tillage had the greatest plant available water content while subsoiling-ripping tillage had the least in all seasons. Averaged across seasons and cropping season, tillage did not have a significant effects on maize grain yield but it did have a significant effect on crop grain and dry matter water use efficiency (WUE). Nevertheless, maize grain yields and WUE values were generally greater under tied-ridge tillage than under subsoiling-ripping and ox-plough tillages. The yields and WUE of cowpea under subsoiling-ripping tillage were less than those of ox-plough tillage. When averaged across the seasons and tillage systems, the cropping system with the manure treatment increased (P.0.05) maize grain yield, grain WUE and dry matter WUE by 36%, 30%, 26% respectively, compared to treatments without manure. Maize and cowpea when intercropped under ox-plough and ripping tillage systems did not have any yield advantage over the single crop

  2. Silicon improves salt tolerance by increasing root water uptake in Cucumis sativus L.

    Science.gov (United States)

    Zhu, Yong-Xing; Xu, Xuan-Bin; Hu, Yan-Hong; Han, Wei-Hua; Yin, Jun-Liang; Li, Huan-Li; Gong, Hai-Jun

    2015-09-01

    Silicon enhances root water uptake in salt-stressed cucumber plants through up-regulating aquaporin gene expression. Osmotic adjustment is a genotype-dependent mechanism for silicon-enhanced water uptake in plants. Silicon can alleviate salt stress in plants. However, the mechanism is still not fully understood, and the possible role of silicon in alleviating salt-induced osmotic stress and the underlying mechanism still remain to be investigated. In this study, the effects of silicon (0.3 mM) on Na accumulation, water uptake, and transport were investigated in two cucumber (Cucumis sativus L.) cultivars ('JinYou 1' and 'JinChun 5') under salt stress (75 mM NaCl). Salt stress inhibited the plant growth and photosynthesis and decreased leaf transpiration and water content, while added silicon ameliorated these negative effects. Silicon addition only slightly decreased the shoot Na levels per dry weight in 'JinYou 1' but not in 'JinChun 5' after 10 days of stress. Silicon addition reduced stress-induced decreases in root hydraulic conductivity and/or leaf-specific conductivity. Expressions of main plasma membrane aquaporin genes in roots were increased by added silicon, and the involvement of aquaporins in water uptake was supported by application of aquaporin inhibitor and restorative. Besides, silicon application decreased the root xylem osmotic potential and increased root soluble sugar levels in 'JinYou 1.' Our results suggest that silicon can improve salt tolerance of cucumber plants through enhancing root water uptake, and silicon-mediated up-regulation of aquaporin gene expression may in part contribute to the increase in water uptake. In addition, osmotic adjustment may be a genotype-dependent mechanism for silicon-enhanced water uptake in plants.

  3. 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...

  4. Water uptake of clay and desert dust aerosol particles at sub- and supersaturated water vapor conditions.

    Science.gov (United States)

    Herich, Hanna; Tritscher, Torsten; Wiacek, Aldona; Gysel, Martin; Weingartner, Ernest; Lohmann, Ulrike; Baltensperger, Urs; Cziczo, Daniel J

    2009-09-28

    Airborne mineral dust particles serve as cloud condensation nuclei (CCN), thereby influencing the formation and properties of warm clouds. It is therefore of atmospheric interest how dust aerosols with different mineralogy behave when exposed to high relative humidity (RH) or supersaturation (SS) with respect to liquid water. In this study the subsaturated hygroscopic growth and the supersaturated cloud condensation nucleus activity of pure clays and real desert dust aerosols were determined using a hygroscopicity tandem differential mobility analyzer (HTDMA) and a cloud condensation nuclei counter (CCNC), respectively. Five different illite, montmorillonite and kaolinite clay samples as well as three desert dust samples (Saharan dust (SD), Chinese dust (CD) and Arizona test dust (ATD)) were investigated. Aerosols were generated both with a wet and a dry disperser. The water uptake was parameterized via the hygroscopicity parameter kappa. The hygroscopicity of dry generated dust aerosols was found to be negligible when compared to processed atmospheric aerosols, with CCNC derived kappa values between 0.00 and 0.02 (the latter corresponds to a particle consisting of 96.7% by volume insoluble material and approximately 3.3% ammonium sulfate). Pure clay aerosols were generally found to be less hygroscopic than natural desert dust particles. The illite and montmorillonite samples had kappa approximately 0.003. The kaolinite samples were less hygroscopic and had kappa=0.001. SD (kappa=0.023) was found to be the most hygroscopic dry-generated desert dust followed by CD (kappa=0.007) and ATD (kappa=0.003). Wet-generated dust showed an increased water uptake when compared to dry-generated samples. This is considered to be an artifact introduced by redistribution of soluble material between the particles. Thus, the generation method is critically important when presenting such data. These results indicate any atmospheric processing of a fresh mineral dust particle which

  5. Uptake of Mn and Cd by Wild Water Spinach and Their Bioaccumulation and Translocation Factors

    OpenAIRE

    Billy Teck Huat Guan; Ferdaus Mohamat-Yusuff; Normala Halimoon; Christina Seok Yien Yong

    2017-01-01

    Polluted ponds and lakes close to agricultural activities become the exposure route of manganese (Mn) and cadmium (Cd) to aquatic plants in near vicinity. Therefore, a study of the uptake, bioaccumulation, and translocation of Mn and Cd by the water spinach (Ipomoea aquatica) is presented in this paper. Different concentrations of Mn and Cd were added to the hydroponic nutrient solution that was used to grow the plants for the heavy metal uptake experiment under greenhouse conditions. The pla...

  6. Toxin distribution and sphingoid base imbalances in Fusarium verticillioides-infected and fumonisin B1-watered maize seedlings.

    Science.gov (United States)

    Arias, Silvina L; Mary, Verónica S; Otaiza, Santiago N; Wunderlin, Daniel A; Rubinstein, Héctor R; Theumer, Martín G

    2016-05-01

    Fusarium verticillioides is a major maize pathogen and there are susceptible and resistant cultivars to this fungal infection. Recent studies suggest that its main mycotoxin fumonisin B1 (FB1) may be involved in phytopathogenicity, but the underlying mechanisms are mostly still unknown. This work was aimed at assessing whether FB1 disseminates inside the plants, as well as identifying possible correlations between the maize resistant/susceptible phenotype and the unbalances of the FB1-structurally-related sphingoid base sphinganine (Sa) and phytosphingosine (Pso) due to toxin accumulation. Resistant (RH) and susceptible hybrid (SH) maize seedlings grown from seeds inoculated with a FB1-producer F. verticillioides and from uninoculated ones irrigated with FB1 (20 ppm), were harvested at 7, 14 and 21 days after planting (dap), and the FB1, Sa and Pso levels were quantified in roots and aerial parts. The toxin was detected in roots and aerial parts for inoculated and FB1-irrigated plants of both hybrids. However, FB1 levels were overall higher in SH seedlings regardless of the treatment (infection or watering). Sa levels increased substantially in RH lines, peaking at 54-fold in infected roots at 14 dap. In contrast, the main change observed in SH seedlings was an increase of Pso in infected roots at 7 dap. Here, it was found that FB1 disseminates inside seedlings in the absence of FB1-producer fungal infections, perhaps indicating this might condition the fungus-plant interaction before the first contact. Furthermore, the results strongly suggest the existence of at least two ceramide synthase isoforms in maize with different substrate specificities, whose differential expression after FB1 exposure could be closely related to the susceptibility/resistance to F. verticillioides. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

    NARCIS (Netherlands)

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

    2010-01-01

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

  8. The effect of water uptake on the mechanical properties of low-k organosilica glass

    Science.gov (United States)

    X. Guo; J.E. Jakes; M.T. Nichols; S. Banna; Y. Nishi; J.L. Shohet

    2013-01-01

    Water uptake in porous low-k dielectrics has become a significant challenge for both back-end-of line integration and circuit reliability. The influence of absorbed water on the mechanical properties of plasma-enhanced chemical-vapor-deposited organosilicate glasses (SiCOH) was investigated with nanoindentation. The roles of physisorbed (α-...

  9. Water uptake in woody riparian phreatophytes of the southwestern United States: a stable isotope study

    International Nuclear Information System (INIS)

    Busch, D.E.; Ingraham, N.L.; Smith, S.D.

    1992-01-01

    Alluvial forest associations are often dominated by woody phreatophytes, plants that are tightly linked to aquifers for water uptake. Anthropogenic hydrological alterations (e.g., water impoundment or diversion) are of clear importance to riparian ecosystem function. Because decreased frequency of flooding and depression of water tables may, in effect, sever riparian plants from their natural water sources, research was undertaken to determine water uptake patterns for the dominant native and introduced woody taxa of riparian plant communities of the southwestern United States. At floodplain study sites along the Bill Williams and lower Colorado Rivers (Arizona, USA), naturally occurring D and 18 O were used to distinguish among potential water sources. Isotopic ratios from potential uptake locations were compared to water extracted from the dominant woody taxa of the study area (Populus fremontii, Salix gooddingii, and Tamarix ramosissima) to elucidate patterns of water absorption. Isotopic composition of water obtained from sapwood cores did not differ significantly from heartwood or branch water, suggesting that heartwood water exchange, stem capacitance, and phloem sap mixing may be inconsequential in actively transpiring Salix and Populus. There was evidence for close hydrologic linkage of river, ground, and soil water during the early part of the growing season. Surface soils exhibited D enrichment due to cumulative exposure to evaporation as the growing season progressed. Isotopic ratios of water extracted from Populus and Salix did not exhibit isotopic enrichment and were not significantly different from groundwater or saturated soil water sources, indicating a phreatophytic uptake pattern. Associations of isotopic ratios with water relations parameters indicated high levels of canopy evaporation and possible use of moisture from unsaturated alluvial soils in addition to groundwater in Tamarix. (author)

  10. The uptake of radioactive phosphorus by brown trout (Salmo trutta L.) from water and food

    International Nuclear Information System (INIS)

    Winpenny, K.; Knowles, J.F.; Smith, D.L.

    1998-01-01

    Brown trout were exposed to 32 P in their tank water (7.4 Bq l -1 ) and the uptake to muscle followed over 6 weeks. A steady-state concentration factor (C ss ) of 1.7 and a biological half-time for clearance (tb1/2)) of 45 days were calculated from the results. The low C ss ) indicates that uptake from water is not a major route of 32 P accumulation in these fish. Brown trout were given a single 32 P-spiked meal, and the uptake and clearance in muscle, liver and blood followed over 6 weeks. Assimilation of the isotope by these organs was low, the maximum activity in whole muscle reaching only 0.2-0.4% of that in the meal with lower values in the other two organs. There was no appreciable clearance of 32 P from muscle during the experiment. The slow clearance of 32 P after uptake from water and lack of any clearance after uptake from food indicates that the C ss for this isotope following uptake by either route is likely to depend on radioactive decay rather than intake rate and physiological clearance. (author)

  11. Simple physics-based models of compensatory plant water uptake: concepts and eco-hydrological consequences

    Directory of Open Access Journals (Sweden)

    N. J. Jarvis

    2011-11-01

    Full Text Available Many land surface schemes and simulation models of plant growth designed for practical use employ simple empirical sub-models of root water uptake that cannot adequately reflect the critical role water uptake from sparsely rooted deep subsoil plays in meeting atmospheric transpiration demand in water-limited environments, especially in the presence of shallow groundwater. A failure to account for this so-called "compensatory" water uptake may have serious consequences for both local and global modeling of water and energy fluxes, carbon balances and climate. Some purely empirical compensatory root water uptake models have been proposed, but they are of limited use in global modeling exercises since their parameters cannot be related to measurable soil and vegetation properties. A parsimonious physics-based model of uptake compensation has been developed that requires no more parameters than empirical approaches. This model is described and some aspects of its behavior are illustrated with the help of example simulations. These analyses demonstrate that hydraulic lift can be considered as an extreme form of compensation and that the degree of compensation is principally a function of soil capillarity and the ratio of total effective root length to potential transpiration. Thus, uptake compensation increases as root to leaf area ratios increase, since potential transpiration depends on leaf area. Results of "scenario" simulations for two case studies, one at the local scale (riparian vegetation growing above shallow water tables in seasonally dry or arid climates and one at a global scale (water balances across an aridity gradient in the continental USA, are presented to illustrate biases in model predictions that arise when water uptake compensation is neglected. In the first case, it is shown that only a compensated model can match the strong relationships between water table depth and leaf area and transpiration observed in riparian forest

  12. Relative Water Uptake as a Criterion for the Design of Trickle Irrigation Systems

    Science.gov (United States)

    Communar, G.; Friedman, S. P.

    2008-12-01

    Previously derived analytical solutions to the 2- and 3-dimensional water flow problems describing trickle irrigation are not being widely used in practice because those formulations either ignore root water uptake or refer to it as a known input. In this lecture we are going to describe a new modeling approach and demonstrate its applicability for designing the geometry of trickle irrigation systems, namely the spacing between the emitters and drip lines. The major difference between our and previous modeling approaches is that we refer to the root water uptake as to the unknown solution of the problem and not as to a known input. We postulate that the solution to the steady-state water flow problem with a root sink that is acting under constant, maximum suction defines un upper bound to the relative water uptake (water use efficiency) in actual transient situations and propose to use it as a design criterion. Following previous derivations of analytical solutions we assume that the soil hydraulic conductivity increases exponentially with its matric head, which allows the linearization of the Richards equation, formulated in terms of the Kirchhoff matric flux potential. Since the transformed problem is linear, the relative water uptake for any given configuration of point or line sources and sinks can be calculated by superposition of the Green's functions of all relevant water sources and sinks. In addition to evaluating the relative water uptake, we also derived analytical expressions for the steam functions. The stream lines separating the water uptake zone from the percolating water provide insight to the dependence of the shape and extent of the actual rooting zone on the source- sink geometry and soil properties. A minimal number of just 3 system parameters: Gardner's (1958) alfa as a soil type quantifier and the depth and diameter of the pre-assumed active root zone are sufficient to characterize the interplay between capillary and gravitational effects on

  13. An analysis of the physiological FDG uptake in the stomach with the water gastric distention method

    International Nuclear Information System (INIS)

    Kamimura, Kiyohisa; Fujita, Seigo; Yano, Tatsuhiko; Ogita, Mikio; Umemura, Yoshiro; Fujimoto, Toshiro; Nishii, Ryuichi; Wakamatsu, Hideyuki; Nagamachi, Shigeki; Nakajo, Masayuki

    2007-01-01

    Physiological FDG uptake in the stomach is a common phenomenon, especially noted at the cardia. Water intake just before scanning will result in gastric distention and thinning of the gastric wall, which in turn may lead to a reduction in the physiological uptake in the gastric wall. In the current study, we investigated whether gastric distention by water intake just before PET imaging reduces physiological FDG uptake in the stomach. The patient population comprised 60 patients who underwent whole-body FDG-PET imaging for cancer screening following gastroscopy performed within the preceding week. All patients took 400 ml of water for hydration and were administered 185 MBq of FDG intravenously. The patients were randomly divided into two groups: a group with additional water intake (AW group; n = 30) and a group without additional water intake (NW group; n = 30). In the AW group, an additional 400 ml of water was given just before PET imaging. For quantitative analysis, the stomach was classified into three areas [upper (U), middle (M) and lower (L)], and the degree of FDG uptake in each area was evaluated using standardised uptake values (SUVs). In the NW group, the mean SUVs in the U, M and L areas were 2.41 ± 0.75, 2.28 ± 0.73 and 1.61 ± 0.89, respectively, while in the AW group they were 1.82 ± 0.66, 1.73 ± 0.56 and 1.48 ± 0.49, respectively, and 2.21 ± 0.38 in the oesophago-gastric junction. The mean SUVs in the U and M areas in the AW group were significantly lower than those in the NW group (p < 0.05). Additional water intake just before PET imaging is an effective method for suppressing physiological FDG uptake in the stomach. (orig.)

  14. Effects of water deficit and nitrogen levels on grain yield and oil and protein contents of maize

    Directory of Open Access Journals (Sweden)

    Kazem Ghassemi-Golezani

    2015-02-01

    Full Text Available This research was conducted in 2014, to evaluate the effects of water deficit and nitrogen fertilizer on grain yield, oil and protein contents of maize (cv. double Cross 303. The experiment was arranged as split-plot based on Randomized Complete Block design (RCB with three replications. Irrigation treatments (irrigation after 60, 90, 120 and 150 mm evaporation and nitrogen levels (0, 46 and 92 kg N/ha were located in the main and sub plots, respectively. Mean grain yield per unit area decreased with decreasing water availability, but it was improved with increasing nitrogen fertilizer. Grain oil percentage significantly decreased, but protein percentage slightly increased as a result of water deficit. In general, oil and protein yields significantly decreased under moderate and severe water stress, mainly because of decreasing grain yield under these conditions. Nitrogen application decreased oil percentage, but increased protein percentage significantly. Nevertheless, nitrogen fertilizer enhanced oil and protein yields per unit area, with no significant difference between nitrogen rates. These results were positively related with grain yield per unit area in maize.

  15. Water uptake by fresh Indonesian peat burning particles is limited by water-soluble organic matter

    Directory of Open Access Journals (Sweden)

    J. Chen

    2017-09-01

    Full Text Available The relationship between hygroscopic properties and chemical characteristics of Indonesian biomass burning (BB particles, which are dominantly generated from peatland fires, was investigated using a humidified tandem differential mobility analyzer. In addition to peat, acacia (a popular species at plantation and fern (a pioneering species after disturbance by fire were used for experiments. Fresh Indonesian peat burning particles are almost non-hygroscopic (mean hygroscopicity parameter, κ < 0.06 due to predominant contribution of water-insoluble organics. The range of κ spans from 0.02 to 0.04 (dry diameter = 100 nm, hereinafter for Riau peat burning particles, while that for Central Kalimantan ranges from 0.05 to 0.06. Fern combustion particles are more hygroscopic (κ = 0. 08, whereas the acacia burning particles have a mediate κ value (0.04. These results suggest that κ is significantly dependent on biomass types. This variance in κ is partially determined by fractions of water-soluble organic carbon (WSOC, as demonstrated by a correlation analysis (R = 0.65. κ of water-soluble organic matter is also quantified, incorporating the 1-octanol–water partitioning method. κ values for the water extracts are high, especially for peat burning particles (A0 (a whole part of the water-soluble fraction: κ = 0.18, A1 (highly water-soluble fraction: κ = 0.30. This result stresses the importance of both the WSOC fraction and κ of the water-soluble fraction in determining the hygroscopicity of organic aerosol particles. Values of κ correlate positively (R = 0.89 with the fraction of m∕z 44 ion signal quantified using a mass spectrometric technique, demonstrating the importance of highly oxygenated organic compounds to the water uptake by Indonesian BB particles. These results provide an experimentally validated reference for hygroscopicity of organics-dominated particles, thus contributing to more accurate

  16. Effect of Gamma Irradiation on Water Uptake Rate and Gelatinization of Brown Rice

    International Nuclear Information System (INIS)

    Shu, C.S.; Lee, J.W.; Lee, Y.S.; Byun, M.W.

    2004-01-01

    Effects of gamma irradiation on brown rice quality were evaluated. Brown rice was irradiated at absorbed dose of 1, 3 or 5 kGy, and ground. Water uptake, pasting properties, and physicochemical characteristics of flour samples were tested. Water uptake rates of irradiated samples were higher than that of control, and were dose-dependent. Hydration capacity decreased in sample irradiated at 5 kGy due to leaching out of soluble compounds, whereas no differences were observed among other irradiated samples and control

  17. [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.

  18. Tests to determine water uptake behaviour of tunnel backfill

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, David (Atomic Energy of Canada Limited (AECL) (Canada)); Anttila, S.; Viitanen, M. (Poeyry InfRa Oy (Finland)); Keto, Paula (Saanio and Riekkola Oy, Helsinki (Finland))

    2008-12-15

    A series of 27 large-scale tests have been completed at the 420 level of SKB's Aespoe Hard Rock Laboratory. These tests have examined the influence of natural Aespoe fracture zone water on the movement of water into and through assemblies of Friedland clay blocks and bentonite pellets/ granules. These tests have established the manner in which groundwater may influence backfill and backfilling operations at the repository-scale. Tests have established that it is critical to provide a clay block backfilling system with lateral support and confinement as quickly as possible following block installation. Exposure of the blocks to even low rates of water ingress can result in rapid loss of block cohesion and subsequent slumping of the block materials into the spaces between the blocks and the tunnel walls. Installation of granular or pelletized bentonite clay between the blocks and the walls resulted in a system that was generally stable and not prone to unacceptable short-term strains as water entered. Inflow of water into a backfilled volume does not result in uniform wetting of the pellet/granule filled volume and as a result there is the potential for rapid movement of water from the point(s) of ingress to the downstream face of the backfill. Depending on the inflow rate and flow path(s) developed this flow can be via discrete flow channels that are essentially non-erosive or else they can develop highly erosive flow paths through the clay block materials. Erosion generally tends to be highest in the period immediately following first water exit from the backfill and then decreases as preferential flow paths develop to channel the water directly through the backfill, bypassing large volumes of unsaturated backfill. At the scale examined in this study inflow rates of 0.1 l/min or less do not tend to be immediately problematic when the source is 0.6 m distant from the downstream face of the backfill. At larger scales or longer distances from the working face, it

  19. Tests to determine water uptake behaviour of tunnel backfill

    International Nuclear Information System (INIS)

    Dixon, David; Anttila, S.; Viitanen, M.; Keto, Paula

    2008-12-01

    A series of 27 large-scale tests have been completed at the 420 level of SKB's Aespoe Hard Rock Laboratory. These tests have examined the influence of natural Aespoe fracture zone water on the movement of water into and through assemblies of Friedland clay blocks and bentonite pellets/ granules. These tests have established the manner in which groundwater may influence backfill and backfilling operations at the repository-scale. Tests have established that it is critical to provide a clay block backfilling system with lateral support and confinement as quickly as possible following block installation. Exposure of the blocks to even low rates of water ingress can result in rapid loss of block cohesion and subsequent slumping of the block materials into the spaces between the blocks and the tunnel walls. Installation of granular or pelletized bentonite clay between the blocks and the walls resulted in a system that was generally stable and not prone to unacceptable short-term strains as water entered. Inflow of water into a backfilled volume does not result in uniform wetting of the pellet/granule filled volume and as a result there is the potential for rapid movement of water from the point(s) of ingress to the downstream face of the backfill. Depending on the inflow rate and flow path(s) developed this flow can be via discrete flow channels that are essentially non-erosive or else they can develop highly erosive flow paths through the clay block materials. Erosion generally tends to be highest in the period immediately following first water exit from the backfill and then decreases as preferential flow paths develop to channel the water directly through the backfill, bypassing large volumes of unsaturated backfill. At the scale examined in this study inflow rates of 0.1 l/min or less do not tend to be immediately problematic when the source is 0.6 m distant from the downstream face of the backfill. At larger scales or longer distances from the working face, it is

  20. Water-Soluble Lignins from Different Bioenergy Crops Stimulate the Early Development of Maize (Zea mays, L.

    Directory of Open Access Journals (Sweden)

    Davide Savy

    2015-11-01

    Full Text Available The molecular composition of water-soluble lignins isolated from four non-food bioenergy crops (cardoon CAR, eucalyptus EUC, and two black poplars RIP and LIM was characterized in detail, and their potential bioactivity towards maize germination and early growth evaluated. Lignins were found to not affect seed germination rates, but stimulated the maize seedling development, though to a different extent. RIP promoted root elongation, while CAR only stimulated the length of lateral seminal roots and coleoptile, and LIM improved only the coleoptile development. The most significant bioactivity of CAR was related to its large content of aliphatic OH groups, C-O carbons and lowest hydrophobicity, as assessed by 31P-NMR and 13C-CPMAS-NMR spectroscopies. Less bioactive RIP and LIM lignins were similar in composition, but their stimulation of maize seedling was different. This was accounted to their diverse content of aliphatic OH groups and S- and G-type molecules. The poorest bioactivity of the EUC lignin was attributed to its smallest content of aliphatic OH groups and largest hydrophobicity. Both these features may be conducive of a EUC conformational structure tight enough to prevent its alteration by organic acids exuded from vegetal tissues. Conversely the more labile conformational arrangements of the other more hydrophilic lignin extracts promoted their bioactivity by releasing biologically active molecules upon the action of exuded organic acids. Our findings indicate that water-soluble lignins from non-food crops may be effectively used as plant biostimulants, thus contributing to increase the economic and ecological liability of bio-based industries.

  1. Participatory Irrigation Management and Irrigation Water Use Efficiency in Maize Production: Evidence from Zhangye City, Northwestern China

    Directory of Open Access Journals (Sweden)

    Qing Zhou

    2017-10-01

    Full Text Available Water has become increasingly scarce in northwestern China due to climate change, economic growth and burgeoning population. Improving agriculture water use efficiency is of strategic significance in promoting socio-economic water productivity for arid and semi-arid inland river basins. Based on the household-level data collected in Zhangye City, which is located in the middle reaches of Heihe River Basin (HRB in northwestern China, irrigation water use efficiency (IWUE of maize is estimated based on stochastic frontier analysis. The impacts of influential factors, especially the participatory irrigation management (PIM through water user associations (WUAs, on IWUE were further examined. Results show that the estimated average Technical efficiency (TE and IWUE of maize production are 0.74 and 0.24, respectively. The participation level in irrigation management is very low, with only 40% of the respondents participating in WUA meetings. In addition, most have a relatively superficial understanding of the roles and management scheme of WUAs. Empirical results show that though significantly positive, the magnitude of the impact of PIM on IWUE is relatively small. Households that participated in WUA meetings achieved only 0.002% higher IWUEs than those have never participated in. WUAs are not operating with their designed objectives. Consequently, reform of the traditional management form of WUAs to make them more transparent, fair, and extensively participated in among farmers is in urgently need. In addition, we also find that water price, source of irrigation water, irrigation technology adoption and famers’ education level and farming experience also have significant positive impacts on IWUE.

  2. [Effects of different tillage patterns on soil properties, maize yield and water use efficiency in Weibei Highland, China.

    Science.gov (United States)

    Liu, Dan; Zhang, Xia; Li, Jun; Wang, Xu-Dong

    2018-02-01

    An eight-year field experiment of straw returning was conducted on dark loessial soil in Weibei Highland to investigate the effects of tillage patterns on soil aggregate, soil organic carbon (SOC), corn yield and soil water use efficiency (WUE). There were six tillage patterns, including conventional tillage (CT/CT), no-tillage (NT/NT), subsoiling tillage (ST/ST), no-tillage/subsoiling tillage (NT/ST), conventional tillage/no-tillage (CT/NT) and conventional tillage/subsoiling tillage (CT/ST). The results showed that compared with CT/CT, the patterns of NT/NT, ST/ST and the rotational tillage patterns (NT/ST, CT/NT and CT/ST) decreased the mean mass diameter of soil mechanical stable aggregate. The patterns of NT/NT, ST/ST and NT/ST increased the content of soil water-stable aggregate with the particle size >0.25 mm (WR 0.25 ) and their mean mass diameter, especially in the depth of 20-50 cm. These patterns reduced the proportion of aggregate destruction (PAD). Compared with CT/CT, the patterns of NT/ST, CT/NT, NT/NT and ST/ST increased the content of SOC in 0-10 cm soil layer. The content of SOC decreased as the increases of soil depth for all tillage patterns, but the decrease in SOC of three single tillage patterns (ST/ST, NT/NT and CT/CT) was larger than that of three rotational tillage patterns. Compared with CT/CT, the other five tillage patterns increased soil water storage in 0-200 cm soil profile, crop yield and WUE in maize. The yield and WUE in NT/ST pattern were significantly increased by 15.1% and 27.5%, respectively. Both corn yield and WUE were significantly and positively correlated with soil water storage in 0-200 cm soil profile in field during the cropping and fallow periods. Moreover, soil water storage during the cropping period was positively correlated with WR 0.25 , but negatively correlated with PAD in 0-50 cm soil layer. Particularly, maize yield, WUE and soil water storage during the cropping period were closely related to WR 0.25 in 20

  3. The role of cattle manure in enhancing on-farm productivity, macro- and micro-nutrient uptake, and profitability of maize in the Guinea savanna

    NARCIS (Netherlands)

    Franke, A.C.; Diels, J.; Schulz, S.; Oyewole, B.D.; Tobe, O.

    2008-01-01

    An on-farm trial was conducted in the northern Guinea savanna of Nigeria, over a period of five years, with the objectives of quantifying the effects on maize of applying cattle manure in combination with synthetic fertilizer with regard to soil characteristics, yield, plant nutrition and

  4. Impact of palmitic acid coating on the water uptake and loss of ammonium sulfate particles

    Directory of Open Access Journals (Sweden)

    R. M. Garland

    2005-01-01

    Full Text Available While water insoluble organics are prevalent in the atmosphere, it is not clear how the presence of such species alters the chemical and physical properties of atmospheric aerosols. Here we use a combination of FTIR spectroscopy, Transmission Electron Microscopy (TEM and Aerosol Mass Spectrometry (AMS to characterize ammonium sulfate particles coated with palmitic acid. Coated aerosols were generated by atomizing pure ammonium sulfate, mixing the particles with a heated flow of nitrogen with palmitic acid vapor, and then flowing the mixture through an in-line oven to create internally mixed particles. The mixing state of the particles was probed using the AMS data and images from the TEM. Both of these probes suggest that the particles were internally mixed. Water uptake by the mixed particles was then probed at 273 K. It was found that for ammonium sulfate containing ~20 wt% palmitic acid the deliquescence relative humidity (DRH was the same as for pure ammonium sulfate (80±3% RH. For particles with ~50 wt% palmitic acid however, the mixed particles began to take up water at relative humidities as low at 69% and continued to slowly take up water to 85% RH without fully deliquescing. In addition to studies of water uptake, water loss was also investigated. Here coatings of up to 50 wt% had no impact on the efflorescence relative humidity. These studies suggest that even if insoluble substances coat salt particles in the atmosphere, there may be relatively little effect on the resulting water uptake and loss.

  5. Response of water deficit regime and soil amelioration on evapotranspiration loss and water use efficiency of maize (Zea mays l.) in subtropical northeastern Himalayas.

    Science.gov (United States)

    Marwein, M A; Choudhury, B U; Chakraborty, D; Kumar, M; Das, A; Rajkhowa, D J

    2017-05-01

    Rainfed maize production in the hilly ecosystem of Northeastern Himalayas often suffers from moisture and soil acidity induced abiotic stresses. The present study measured evapotranspiration loss (ET c ) of maize crop under controlled condition (pot experiment) of water deficit (W 25 -25 % and W 50 -50 % of field capacity soil moistures) and well watered (W 100  = 100 % of field capacity (FC)) regimes in strong acid soils (pH = 4.3) of the Northeastern Himalayan Region of India. The response of soil ameliorants (lime) and phosphorus (P) nutrition under differential water regimes on ET c losses and water use efficiency was also studied. The measured seasonal ET c loss varied from 124.3 to 270.9 mm across treatment combinations. Imposition of water deficit stress resulted in significant (p losses but was at the cost of delay in tasseling to silking, 47-65 % reduction in dry matter accumulation (DMA), 12-22 days shortening of grain formation period, and complete kernel abortion. Liming @ 4 t ha -1 significantly (p losses and DMA across water regimes but the magnitude of increase was higher in severely water deficit (W 25 ) regime. Unlike lime, P nutrition improved DMA only in well-watered regimes (W 100 ) while seasonal ET c loss was unaffected. Vegetative stage (tillering to tasseling) contributed the maximum ET c losses while weekly crop ET c loss was estimated highest during 11th-14th week after sowing (coincided with blistering stage) and then declined. Water use efficiency estimated from dry matter produced per unit ET c losses and irrigation water used varied from 4.33 to 9.43 g dry matter kg -1  water and 4.21 to 8.56 g dry matter kg -1 , respectively. Among the input factors (water, P, and lime), water regime most strongly influenced the ET c loss, growth duration, grain formation, and water use efficiency of maize.

  6. Water Uptake and Acid Doping of Polybenzimidazoles as Electrolyte Membranes for Fuel Cells

    DEFF Research Database (Denmark)

    Qingfeng, Li; He, R.; Berg, Rolf W.

    2004-01-01

    Acid-doped polybenzimidazole (PBI) membranes have been demonstrated for fuel cell applications with advanced features such as high operating temperatures, little humidification, excellent CO tolerance, and promising durability. The water uptake and acid doping of PBI membranes have been studied...

  7. Foliar uptake of cesium from the water column by aquatic macrophytes

    Energy Technology Data Exchange (ETDEWEB)

    Pinder, J.E. [Savannah River Ecology Laboratory, University of Georgia, Drawer E, Aiken, SC 29801 (United States); Hinton, T.G. [Savannah River Ecology Laboratory, University of Georgia, Drawer E, Aiken, SC 29801 (United States)]. E-mail: thinton@srel.edu; Whicker, F.W. [Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523-1618 (United States)

    2006-07-01

    The probable occurrence and rate of foliar absorption of stable cesium ({sup 133}Cs) from the water column by aquatic macrophyte species was analyzed following the addition of {sup 133}Cs into a small reservoir near Aiken, South Carolina, USA. An uptake parameter u (10{sup 3} L kg{sup -1} d{sup -1}) and a loss rate parameter k (d{sup -1}) were estimated for each species using time series of {sup 133}Cs concentrations in the water and plant tissues. Foliar uptake, as indicated by rapid increases in plant concentrations following the {sup 133}Cs addition, occurred in two floating-leaf species, Brasenia schreberi and Nymphaea odorata, and two submerged species, Myriophyllum spicatum and Utricularia inflata. These species had values of u {>=} 0.75 x 10{sup 3} L kg{sup -1} d{sup -1}. Less evidence for foliar uptake was observed in three emergent species, including Typha latifolia. Ratios of u to k for B. schreberi, M. spicatum, N. odorata and U. inflata can be used to estimate concentration ratios (CR) at equilibrium, and these estimates were generally within a factor of 2 of the CR for {sup 137}Cs for these species in the same reservoir. This correspondence suggests that foliar uptake of Cs was the principal absorption mechanism for these species. Assessments of: (1) the prevalence of foliar uptake of potassium, rubidium and Cs isotopes by aquatic macrophytes and (2) the possible importance of foliar uptake of Cs in other lentic systems are made from a review of foliar uptake studies and estimation of comparable u and k values from lake studies involving Cs releases.

  8. Brackish water for irrigation: IV. effects on yield of maize (zea mays l.) and saturated hydraulic conductivity of soil

    International Nuclear Information System (INIS)

    Abid, M.; Anwar-ur-Hassan; Ghafoor, A.

    2003-01-01

    The experiment was conducted to investigate the effect of brackish water irrigation on fresh biomass yield of maize variety Agati-72 and saturated hydraulic conductivity (HC) of silty clay loam soil. Total 20 treatment combinations having different EC/sub iw/ (0.65, 2.0, 4.0, 6.0 and 7.35 dS m/sup -1/), SAR/sub iw/ (3.95, 9.65, 18.0, 26.35 and 32.04 (mmol L/sup -1)/sup 1/2/) and RSC (0.65, 2.0, 4.0, 6.0 and 7.35 mmol/sub c/ L/sup -1/) were applied to 30 cm x 68 cm undisturbed and disturbed soil columns. Results indicated that biomass yield of maize decreased with an increase in EC/sub iw/ from 0.65 to 7.35 dS m/sup -1/ at coded 0 levels of SAR/sub iw/ and RSC in undisturbed soil. The maize tolerated EC/sub iw/ up to 2.0 dS m/sup-1/ at coded 0 levels of SAR/sub iw/ and RSC in disturbed soil. The SAR/sub iw/ up to 18.0 did not affect the yield of crop at coded 0 levels of EC/sub iw/ for the undisturbed and disturbed soils, respectively. The increase in HC was 48% in undisturbed and 54% in disturbed soils with EC/sub iw/ 7.35 dS m/sup -1/ over EC/sub iw/ 0.65 dS m/sup -1/ coded 0 levels of EC/sub iw/ and RSC. The HC decreased with SAR/sub iw/ and RSC at coded 0 levels of EC/sub iw/ and RSC; EC/sub iw/ and SAR/sub iw/ in both the soil columns. (author)

  9. [Spatiotemporal dynamics of maize water suitability and assessment of agricultural drought in Liaoning Province, China from 1981 to 2010].

    Science.gov (United States)

    Cai, Fu; Zhang, Shu-jie; Ji, Rui-peng; Mi, Na; Wu, Jin-wen; Zhang, Yu-shu

    2015-01-01

    Maize water suitability (MWS) model was developed at growth stage scale. Frequency and severity of drought were evaluated by combining MWS estimates and agricultural meteorological drought indexes. The MWS at each growth stage was calculated by using maize observational data and conventional meteorological data at 52 sites in Liaoning during the period from 1981 to 2010. Based on the climatic trend and abrupt change analysis, spatiotemporal dynamics of MWS were investigated. Meanwhile, occurrence of agricultural drought and its severity were also estimated. The results showed that the variation of MWS largely differed at different growth stages. Climatic abrupt change happened in 1994, 1996 and 1999 at the stages of emergence to seven leaves (II), jointing to tasseling (IV) and physiological maturity to maturity (VI). During the past 30 years, MWS showed an obvious increasing trend at the stages of sowing to emergence(I) , seven leaves to jointing(III), IV and tasseling to physiological maturity(V), while it showed a decreasing trend at the stages of II and VI, and that at VI stage was statistically significant. In addition, the climatic trend of MWS showed apparently spatial variability. The frequencies of drought at different severities varied with maize growth stages. Areas of high variability of MWS were located in the Northwest and South of Liaoning at the stages of I , II , III and VI, where were also the regions of high frequency of mid- and severe-drought. At the stages of IV and V, the frequency of drought was low and only light- and mid-drought occurred in few areas. In conclusion, the regional mean MWS could be capable to reasonably assess the agricultural drought in Liaoning at the regional scale.

  10. Uptake of radioactive strontium by fishes in relation to the calcium content of the water

    International Nuclear Information System (INIS)

    Chiosila, J.

    1975-01-01

    The study attempts to compare experimental results obtained with pseudorasbora parava with regard to 85 Sr uptake at various Ca concentrations of the water (4.20 and 50 mg/l Ca) and also to compare these results with natural conditions. The water was contaminated with 500 pCi/ml 85 SrCl 2 only at the onset of the experiments. Radiostrontium uptake is much higher with a very low calcium content of the water; maximum values are reached in about 10 days. - With low or optimum calcium contents of the water, the values are 3-5 times lower and are not reached until 30 days after radioactive contamination. The fish in this Danube water experiment took up somewhat less radioactivity than in an experiment with the same amounts of Ca and Mg in a control medium. The uptake of 85 Sr in fish in dependence of the Ca content of the water varies according to the formula F.C = 2.505 x Casup(-0.909), with Ca given in Mg/l. (orig.) [de

  11. Representing the root water uptake process in the Common Land Model for better simulating the energy and water vapour fluxes in a Central Asian desert ecosystem

    NARCIS (Netherlands)

    Li, Longhui; van der Tol, C.; Chen, Xuelong; Jing, C.; Su, Zhongbo; Luo, G.; Tian, Xin

    2013-01-01

    The ability of roots to take up water depends on both root distribution and root water uptake efficiency. The former can be experimentally measured, while the latter is extremely difficult to determine. Yet a correct representation of root water uptake process in land surface models (LSMs) is

  12. Seed Anatomy and Water Uptake in Relation to Seed Dormancy in Opuntia tomentosa (Cactaceae, Opuntioideae)

    Science.gov (United States)

    Orozco-Segovia, A.; Márquez-Guzmán, J.; Sánchez-Coronado, M. E.; Gamboa de Buen, A.; Baskin, J. M.; Baskin, C. C.

    2007-01-01

    Background and Aims There is considerable confusion in the literature concerning impermeability of seeds with ‘hard’ seed coats, because the ability to take up (imbibe) water has not been tested in most of them. Seeds of Opuntia tomentosa were reported recently to have a water-impermeable seed coat sensu lato (i.e. physical dormancy), in combination with physiological dormancy. However, physical dormancy is not known to occur in Cactaceae. Therefore, the aim of this study was to determine if seeds of O. tomentosa are water-permeable or water-impermeable, i.e. if they have physical dormancy. Methods The micromorphology of the seed coat and associated structures were characterized by SEM and light microscopy. Permeability of the seed-covering layers was assessed by an increase in mass of seeds on a wet substrate and by dye-tracking and uptake of tritiated water by intact versus scarified seeds. Key Results A germination valve and a water channel are formed in the hilum–micropyle region during dehydration and ageing in seeds of O. tomentosa. The funicular envelope undoubtedly plays a role in germination of Opuntia seeds via restriction of water uptake and mechanical resistance to expansion of the embryo. However, seeds do not exhibit any of three features characteristic of those with physical dormancy. Thus, they do not have a water-impermeable layer(s) of palisade cells (macrosclereids) or a water gap sensu stricto and they imbibe water without the seed coat being disrupted. Conclusions Although dormancy in seeds of this species can be broken by scarification, they have physiological dormancy only. Further, based on information in the literature, it is concluded that it is unlikely that any species of Opuntia has physical dormancy. This is the first integrative study of the anatomy, dynamics of water uptake and dormancy in seeds of Cactaceae subfamily Opuntioideae. PMID:17298989

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

    NARCIS (Netherlands)

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

    2017-01-01

    A large yield gap exists in rain-fed maize (Zea mays L.) production in semi-arid regions, mainly caused by frequent droughts halfway through the crop-growing period due to uneven distribution of rainfall. It is questionable whether irrigation systems are economically required in such a region

  14. QTL-By-Environment Interaction in the Response of Maize Root and Shoot Traits to Different Water Regimes

    Directory of Open Access Journals (Sweden)

    Pengcheng Li

    2018-02-01

    Full Text Available Drought is a major abiotic stress factor limiting maize production, and elucidating the genetic control of root system architecture and plasticity to water-deficit stress is a crucial problem to improve drought adaptability. In this study, 13 root and shoot traits and genetic plasticity were evaluated in a recombinant inbred line (RIL population under well-watered (WW and water stress (WS conditions. Significant phenotypic variation was observed for all observed traits both under WW and WS conditions. Most of the measured traits showed significant genotype–environment interaction (GEI in both environments. Strong correlations were observed among traits in the same class. Multi-environment (ME and multi-trait (MT QTL analyses were conducted for all observed traits. A total of 48 QTLs were identified by ME, including 15 QTLs associated with 9 traits showing significant QTL-by-Environment interactions (QEI. QTLs associated with crown root angle (CRA2 and crown root length (CRL1 were identified as having antagonistic pleiotropic effects, while 13 other QTLs showed signs of conditional neutrality (CN, including 9 and 4 QTLs detected under WW and WS conditions, respectively. MT analysis identified 14 pleiotropic QTLs for 13 traits, SNP20 (1@79.2 cM was associated with the length of crown root (CR, primary root (PR, and seminal root (SR and might contribute to increases in root length under WS condition. Taken together, these findings contribute to our understanding of the phenotypic and genotypic patterns of root plasticity in response to water deficiency, which will be useful to improve drought tolerance in maize.

  15. Water uptake, migration and swelling characteristics of unsaturated and saturated, highly compacted bentonite

    International Nuclear Information System (INIS)

    Pusch, R.

    1980-09-01

    The report presents the results of a number of laboratory tests and field observations to form the basis of a physical and mathematical model that can be used for predicting water uptake and swelling in highly compacted bentonite components of an actual deposition plant. The clay buffer masses have been suggested as barriers in the Swedish KBS concepts. Two commercially available bentonites were used for the production of samples. The rate of water uptake suggests a mathematical model based on a simple diffusion equation. The rate is determined by the access of water and thousands of years may pass before saturation is obtained. The rate of swelling is governed by the negative pore pressure and the permeability. There is reasonable agreement with field observations. The observed swelling potential of old smectite-rich clays has offered the evidence. (G.B.)

  16. Radiation and storage effects on water uptake and cooking behaviour of mungbean

    International Nuclear Information System (INIS)

    Aurangzeb; Bibi, N.; Badshah, A.; Sattar, A.

    1991-01-01

    Effect of different doses of gamma irradiation (0-10 kGy) and storage for 6 months at room conditions was studied on seed size, water uptake and cooking time of mungbeans. Irradiation exhibited insignificant effect on seed weight, seed volume, density, hydration capacity/index, swelling capacity/index, as well as water hydration capacity (WHC) and pH of flour, but significantly (P .ltoreq. 0.01) reduced the cooking time of mungbean seeds (15.37 to 9.93 min.). Storage time increased the cooking time of this legume (11.55 to 12.75 min.). The water uptake parameters of seed and pH of flour decreased significantly due to storage, whereas seed size (weight and volume) remained unaffected during storage

  17. Influence of tragacanth gum in egg white based bioplastics: Thermomechanical and water uptake properties.

    Science.gov (United States)

    López-Castejón, María Luisa; Bengoechea, Carlos; García-Morales, Moisés; Martínez, Inmaculada

    2016-11-05

    This study aims to extend the range of applications of tragacanth gum by studying its incorporation into bioplastics formulation, exploring the influence that different gum contents (0-20wt.%) exert over the thermomechanical and water uptake properties of bioplastics based on egg white albumen protein (EW). The effect of plasticizer nature was also evaluated through the modification of the water/glycerol ratio within the plasticizer fraction (fixed at 40wt.%). The addition of tragacanth gum generally yielded an enhancement of the water uptake capacity, being doubled at the highest content. Conversely, presence of tragacanth gum resulted in a considerable decrease in the bioplastic mechanical properties: both tensile strength and maximum elongation were reduced up to 75% approximately when compared to the gum-free system. Ageing of selected samples was also studied, revealing an important effect of storage time when tragacanth gum is present, possibly due to its hydrophilic character. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Effect of glycidyl methacrylate (GMA) incorporation on water uptake and conductivity of proton exchange membranes

    Science.gov (United States)

    Sproll, Véronique; Schmidt, Thomas J.; Gubler, Lorenz

    2018-03-01

    The aim of this work was to investigate how hygroscopic moieties like hydrolyzed glycidyl methacrylate (GMA) influence the properties of sulfonated polysytrene based proton exchange membranes (PEM). Therefore, several membranes were synthesized by electron beam treatment of the ETFE (ethylene-alt-tetrafluoroethylene) base film with a subsequent co-grafting of styrene and GMA at different ratios. The obtained membranes were sulfonated to introduce proton conducting groups and the epoxide moiety of the GMA unit was hydrolyzed for a better water absorption. The PEM was investigated regarding its structural composition, water uptake and through-plane conductivity. It could be shown that the density of sulfonic acid groups has a higher influence on the proton conductivity of the PEM than an increased water uptake.

  19. Radionuclides and heavy metal uptake by lolium italicum plant as affected by saline water irrigation

    International Nuclear Information System (INIS)

    Ramadan, A.A.; Aly, A.I.; Helal, M.H.

    2001-01-01

    The use of saline waters to grow crops on increasingly metal polluted soils is becoming a common practice in the arid regions. Nevertheless, the effects of soil and water salinity on radionuclides and heavy metal fluxes in polluted areas are not well understood. The aim of this study was to evaluate in pot experiments the plant uptake of cesium-137, Co-60, Mn-54, Zinc, cadmium and copper from a polluted alluvial aridisol as affected by salt water irrigation. Fertilized soil material was planted in pots with L. Italicum for 18 weeks under greenhouse conditions. The plants were irrigated either with water or with salt solution of variable variable Na/Ca ratio and harvested every 5-7 weeks. In addition to elemental analysis of plants and soil extracts root length was determined by a gridline intersect method and the viable part of the roots was estimated by a root protein inex. Saline (Na) water irrigation increased cobalt-60, manganese-54 and heavy metal solubility in soil, reduced root viability and enhanced the uptake of Co-60, Mn-54, Cd, Cu, Zn and Na by L.italicum and reduced the uptake of Cs-137. Ca counteracted these effects partly. The presented results demonstrated a dual effect of salinity on radiouclides and heavy metal availability to plants and suggest a relationship between root mortality and the enhanced Co-60, Mn-54, and heavy metake ny salt stressed plants

  20. Lipid–water partition coefficients and correlations with uptakes by algae of organic compounds

    International Nuclear Information System (INIS)

    Hung, Wei-Nung; Chiou, Cary T.; Lin, Tsair-Fuh

    2014-01-01

    Graphical abstract: - Highlights: • Partition coefficients of contaminants with lipid triolein (K tw ) are measured. • Measured K tw values are nearly the same as the respective K ow . • Sorption of the contaminants to a dry algal powder is similarly measured. • Algal uptake of a compound occurs primarily by partition into the algal lipid. - Abstract: In view of the scarcity of the lipid–water partition coefficients (K tw ) for organic compounds, the log K tw values for many environmental contaminants were measured using ultra-pure triolein as the model lipid. Classes of compounds studied include alkyl benzenes, halogenated benzenes, short-chain chlorinated hydrocarbons, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and organochlorine pesticides. In addition to log K tw determination, the uptakes of these compounds from water by a dry algal species were measured to evaluate the lipid effect on the algal uptake. The measured log K tw are closely related to their respective log K ow (octanol–water), with log K ow = 1.9 to 6.5. A significant difference is observed between the present and early measured log K tw for compounds with log K ow > ∼5, which is attributed to the presence and absence of a triolein microemulsion in water affecting the solute partitioning. The observed lipid-normalized algae–water distribution coefficients (log K aw/lipid ) are virtually identical to the respective log K tw values, which manifests the dominant lipid-partition effect of the compounds with algae

  1. Neutron radiography for the study of water uptake in painting canvases and preparation layers

    Energy Technology Data Exchange (ETDEWEB)

    Boon, J.J. [Swiss Institute for Art Research (SIK-ISEA), Zurich (Switzerland); FOM Institute AMOLF, Amsterdam (Netherlands); Hendrickx, R.; Ferreira, E.S.B. [Swiss Institute for Art Research (SIK-ISEA), Zurich (Switzerland); Eijkel, G.; Cerjak, I. [FOM Institute AMOLF, Amsterdam (Netherlands); Kaestner, A. [Paul Scherrer Institut, Neutron Imaging and Activation Group, Laboratory for Neutron Scattering and Imaging, Villigen (Switzerland)

    2015-11-15

    Easel paintings on canvas are subjected to alteration mechanisms triggered or accelerated by moisture. For the study of the spatial distribution and kinetics of such interactions, a moisture exposure chamber was designed and built to perform neutron radiography experiments. Multilayered sized and primed canvas samples were prepared for time-resolved experiments in the ICON cold neutron beamline. The first results show that the set-up gives a good contrast and sufficient resolution to visualise the water uptake in the layers of canvas, size and priming. The results allow, for the first time, real-time visualisation of the interaction of water vapour with such layered systems. This offers important new opportunities for relevant, spatially and time-resolved material behaviour studies and opens the way towards numerical modelling of the process. These first results show that cellulose fibres and glue sizing have a much stronger water uptake than the chalk-glue ground. Additionally, it shows that the uptake rate is not uniform throughout the thickness of the sized canvas. With prolonged moisture exposure, a higher amount of water is accumulating at the lower edge of the canvas weave suggesting a decrease in permeability in the sized canvas with increased water content. (orig.)

  2. Uptake of Hg2+ by picocyanobacteria in natural water from four Andean lakes

    Directory of Open Access Journals (Sweden)

    Diéguez M.C.

    2014-07-01

    Full Text Available In lake food webs, planktonic bacteria and algae represent the greatest bioconcentration step for Hg2+ and monomethyl-Hg (MeHg. As they are the most abundant organisms in planktonic trophic webs and also the main food resource for herbivorous plankton, they can mobilize large amounts of Hg to higher trophic levels. In Andean Patagonian lakes (Argentina, dissolved organic matter (DOM concentration and character, coupled with photo-reactions, play a central role in the complexation of Hg2+ in the water column and can even regulate the uptake of Hg2+ by planktonic algae. In this investigation we evaluated the DOM character of natural waters (NW from four Andean lakes and studied its influence on the uptake of 197Hg2+ in a strain of the picocyanobacteria Synechococcus by using Hg2+ labeled with 197Hg2+. The uptake of radiolabeled Hg2+ by Synechococcus showed different magnitude in NW of lakes Moreno, El Trébol, Morenito and Escondido. Increasing lake DOM concentration reduced the bioavailability of Hg2+ as indicated by the lower uptakes rates found in NW with higher complexity and concentration of the DOM pool. Uptakes of Hg2+ by this picocyanobacteria contrasted among NW from pelagic (surface and bottom and littoral compartments of Lake Escondido which suggest that the entry of this metal may be highly variable even in the same environment. The study of the uptake of radiolabeled Hg2+ in a set of dilutions of NW from Lake Escondido demonstrated that the bioavailability of Hg2+ decrease with increasing DOM concentration.

  3. 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

  4. Nutritional and water effect on fluoride uptake and respiration of bean seedlings. [Phaseolus vulgaris

    Energy Technology Data Exchange (ETDEWEB)

    Applegate, H G; Adams, D F

    1960-01-01

    Bean plants (Phaseolus vulgaris) were grown in an atmosphere containing 2.0 +/- 0.21 g F /mT (1.6 ppb). The effect of N, P, K, Fe, and Ca deficiencies and the effect of osmotic pressures of 0, 1.5, 3.0, 4.5, 6.0 and 7.5 pounds on fluoride uptake and fluoride-mediated respiration were studied. The data showed that P deficient plants took up more fluoride than plants deficient in any of the other elements studied. Fluoride-mediated respiration was phosphorous dependent, however. Plants low in Fe or K showed increased uptake of fluoride. Nitrogen had no effect on fluoride uptake under the conditions of this experiment. Plants low in Fe showed inhibition of oxygen uptake. This inhibition was accentuated by fluoride. The interactions of N, K and Ca with fluoride on respiration were complex. Neither fluoride uptake nor fluoride-mediated respiration appeared to be linked directly to the water economy of the plants. 14 references, 6 tables.

  5. Modeling of Soil Water and Salt Dynamics and Its Effects on Root Water Uptake in Heihe Arid Wetland, Gansu, China

    Directory of Open Access Journals (Sweden)

    Huijie Li

    2015-05-01

    Full Text Available In the Heihe River basin, China, increased salinity and water shortages present serious threats to the sustainability of arid wetlands. It is critical to understand the interactions between soil water and salts (from saline shallow groundwater and the river and their effects on plant growth under the influence of shallow groundwater and irrigation. In this study, the Hydrus-1D model was used in an arid wetland of the Middle Heihe River to investigate the effects of the dynamics of soil water, soil salinization, and depth to water table (DWT as well as groundwater salinity on Chinese tamarisk root water uptake. The modeled soil water and electrical conductivity of soil solution (ECsw are in good agreement with the observations, as indicated by RMSE values (0.031 and 0.046 cm3·cm−3 for soil water content, 0.037 and 0.035 dS·m−1 for ECsw, during the model calibration and validation periods, respectively. The calibrated model was used in scenario analyses considering different DWTs, salinity levels and the introduction of preseason irrigation. The results showed that (I Chinese tamarisk root distribution was greatly affected by soil water and salt distribution in the soil profile, with about 73.8% of the roots being distributed in the 20–60 cm layer; (II root water uptake accounted for 91.0% of the potential maximal value when water stress was considered, and for 41.6% when both water and salt stress were considered; (III root water uptake was very sensitive to fluctuations of the water table, and was greatly reduced when the DWT was either dropped or raised 60% of the 2012 reference depth; (IV arid wetland vegetation exhibited a high level of groundwater dependence even though shallow groundwater resulted in increased soil salinization and (V preseason irrigation could effectively increase root water uptake by leaching salts from the root zone. We concluded that a suitable water table and groundwater salinity coupled with proper irrigation

  6. 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 ...

  7. Governance Regime Factors Conducive to Innovation Uptake in Urban Water Management: Experiences from Europe

    Directory of Open Access Journals (Sweden)

    Josselin Rouillard

    2016-10-01

    Full Text Available Innovative ways to manage the urban water cycle are required to deal with an ageing drinking and waste water infrastructure and new societal imperatives. This paper examines the influence of water governance in enabling transformations and technological innovation uptake in urban water management. A governance assessment framework is developed and applied in three case-studies, examining different scales and types of innovations used to tackle challenges in European urban water management. The methodology combines documentary analysis and interviews to reconstruct historical storylines of the shift in the water governance of urban water management for each site. The research provides detailed empirical observations on the factors conducive to innovation uptake at the local level. Critical governance factors such as commitment to compromise, the necessity to build political support, and the role of “entrepreneurs” and coalitions are highlighted. The paper also explores the role of discursive strategies and partnership design, as well as that of regulative, economic and communicative instruments, in creating barriers and opportunities to initiate and secure change. A number of recommendations targeted at innovators and water managers are presented in the conclusion.

  8. The effects of plastic film mulching on maize growth and water use in dry and rainy years in Northeast China.

    Science.gov (United States)

    Xu, Jie; Li, Congfeng; Liu, Huitao; Zhou, Peilu; Tao, Zhiqiang; Wang, Pu; Meng, Qingfeng; Zhao, Ming

    2015-01-01

    Plastic film mulching (PM) has been widely used to improve maize (Zea mays L.) yields and water use efficiency (WUE) in Northeast China, but the effects of PM in a changing climate characterized by highly variable precipitation are not well understood. Six site-year field experiments were conducted in the dry and rainy years to investigate the effects of PM on maize growth, grain yield, and WUE in Northeast China. Compared to crops grown without PM treatment (control, CK), PM significantly increased the grain yield by 15-26% in the dry years, but no significant yield increase was observed in the rainy years. Yield increase in the dry years was mainly due to a large increase in dry matter accumulation pre-silking compared to the CK, which resulted from a greater dry matter accumulation rate due to the higher topsoil temperature and water content. As a result, the WUE of the crops that underwent PM (3.27 kg m(-3)) treatment was also increased by around 16% compared to the CK, although the overall evapotranspiration was similar between the two treatments. In the rainy years, due to frequent precipitation and scant sunshine, the topsoil temperature and water content in the field that received PM treatment was improved only at some stages and failed to cause higher dry matter accumulation, except at the 8th leaf stage. Consequently, the grain yield and WUE were not improved by PM in the rainy years. In addition, we found that PM caused leaf senescence at the late growth stage in both dry and rainy years. Therefore, in practice, PM should be applied cautiously, especially when in-season precipitation is taken into account.

  9. Linking marine resources to ecotonal shifts of water uptake by terrestrial dune vegetation.

    Science.gov (United States)

    Greaver, Tara L; Sternberg, Leonel L da S

    2006-09-01

    As evidence mounts that sea levels are rising, it becomes increasingly important to understand the role of ocean water within terrestrial ecosystem dynamics. Coastal sand dunes are ecosystems that occur on the interface of land and sea. They are classic ecotones characterized by zonal distribution of vegetation in response to strong gradients of environmental factors from the ocean to the inland. Despite the proximity of the dune ecosystem to the ocean, it is generally assumed that all vegetation utilizes only freshwater and that water sources do not change across the ecotone. Evidence of ocean water uptake by vegetation would redefine the traditional interpretation of plant-water relations in the dune ecosystem and offer new ideas for assessing maritime influences on function and spatial distribution of plants across the dune. The purpose of this study was to identify sources of water (ocean, ground, and rain) taken up by vegetation using isotopic analysis of stem water and to evaluate water uptake patterns at the community level based on the distribution and assemblage of species. Three coastal dune systems located in southern Florida, USA, and the Bahamian bank/platform system were investigated. Plant distributions across the dune were zonal for 61-94% of the 18 most abundant species at each site. Species with their highest frequency on the fore dune (nearest the ocean) indicate ocean water uptake as evidenced by delta 18O values of stem water. In contrast, species most frequent in the back dune show no evidence of ocean water uptake. Analysis of species not grouped by frequency, but instead sampled along a transect from the ocean toward the inland, indicates that individuals from the vegetation assemblage closest to the ocean had a mixed water-harvesting strategy characterized by plants that may utilize ocean, ground-, and/or rainwater. In contrast, the inland vegetation relies mostly on rainwater. Our results show evidence supporting ocean water use by dune

  10. Foliar uptake of 137Cs from the water column by aquatic macrophytes

    International Nuclear Information System (INIS)

    Kelly, M.S.; Pinder, J.E. III

    1996-01-01

    A transplant experiment was performed to determine the relative importances of root uptake from the sediments and foliar uptake from the water column in determining the accumulation of 137 Cs by aquatic macrophytes. Uncontaminated individuals of three species, Brasenia schreberi, Nymphaea odorata and Nymphoides cordata, were transplanted into pots containing either contaminated sediments (i.e. 1.2 Bq 137 Cs g -1 dry mass) or uncontaminated sediments (i.e. -1 dry mass) and immersed in Pond B, a former reactor cooling pond where 137 Cs concentrations in surface waters range from 0.4 to 0.8 Bq liter -1 . The plants is uncontaminated sediments rapidly accumulated 137 Cs from the water column and after 35 days of immersion had 137 Cs concentrations in leaves that were: (1) not statistically significantly different from those for plants in contaminated sediments; and (2) similar to those for the same species growing naturally in Pond B. The similarity in 137 Cs concentrations between naturally-occurring plants and those in pots with uncontaminated sediments suggests that foliar uptake from the water column is the principal mode of Cs accumulation by these species in Pond B. (author)

  11. Yield Response of Spring Maize to Inter-Row Subsoiling and Soil Water Deficit in Northern China.

    Science.gov (United States)

    Liu, Zhandong; Qin, Anzhen; Zhao, Ben; Ata-Ul-Karim, Syed Tahir; Xiao, Junfu; Sun, Jingsheng; Ning, Dongfeng; Liu, Zugui; Nan, Jiqin; Duan, Aiwang

    2016-01-01

    Long-term tillage has been shown to induce water stress episode during crop growth period due to low water retention capacity. It is unclear whether integrated water conservation tillage systems, such asspringdeepinter-row subsoiling with annual or biennial repetitions, can be developed to alleviate this issue while improve crop productivity. Experimentswere carried out in a spring maize cropping system on Calcaric-fluvicCambisolsatJiaozuoexperimentstation, northern China, in 2009 to 2014. Effects of threesubsoiling depths (i.e., 30 cm, 40 cm, and 50 cm) in combination with annual and biennial repetitionswasdetermined in two single-years (i.e., 2012 and 2014)againstthe conventional tillage. The objectives were to investigateyield response to subsoiling depths and soil water deficit(SWD), and to identify the most effective subsoiling treatment using a systematic assessment. Annualsubsoiling to 50 cm (AS-50) increased soil water storage (SWS, mm) by an average of8% in 0-20 cm soil depth, 19% in 20-80 cm depth, and 10% in 80-120 cm depth, followed by AS-40 and BS-50, whereas AS-30 and BS-30 showed much less effects in increasing SWS across the 0-120 cm soil profile, compared to the CK. AS-50 significantly reduced soil water deficit (SWD, mm) by an average of123% during sowing to jointing, 318% during jointing to filling, and 221% during filling to maturity, compared to the CK, followed by AS-40 and BS-50. An integrated effect on increasing SWS and reducing SWD helped AS-50 boost grain yield by an average of 31% and biomass yield by 30%, compared to the CK. A power function for subsoiling depth and a negative linear function for SWD were used to fit the measured yields, showing the deepest subsoiling depth (50 cm) with the lowest SWD contributed to the highest yield. Systematic assessment showed that AS-50 received the highest evaluation index (0.69 out of 1.0) among all treatments. Deepinter-row subsoilingwith annual repetition significantly boosts yield by

  12. Uptake of 137Cs in cultured fresh water fish (Cyprinus carpio): physiological and histological effects

    International Nuclear Information System (INIS)

    Vosniakos, F.; Kesidou, A.; Kalfa, A.; Moumtzis, A.; Karakoltsidis, P.

    1991-01-01

    An experiment was conducted in fresh-water fish (Cyprinus carpio) cultured, in small water tanks, artificially contaminated with radioactive 137 Cs (3000 Bq/1) to determine the uptake of 137 Cs and its physiological and histological effects in different fish organs. It was found that 137 Cs was located in muscular tissues, gills, head muscles, liver and kidneys. Moderate amounts were found in spleen, eyes, gonads, intestine and urinary bladder. It seems that sorption was of much less importance than ingestion in the uptake of 137 Cs. The histological examination in musculature tissue, revealed an acute hyperemia with focal haemorrages which may be due to allergic effects of 137 Cs. Hyperemia and focal fatty degeneration of hepatic cells was also noted in the liver which may be due to toxic effects of 137 Cs. Diffused hyperemia has also occurred in the brain and focal degeneration of epithelial cells of renal tubules. (Author)

  13. The dependence of maize (Zea mays hybrids yielding potential on the water amounts reaching the soil surface

    Directory of Open Access Journals (Sweden)

    Kresović Branka

    2013-01-01

    Full Text Available The aim of the present study was to observe the response of maize hybrids under rainfed and irrigation conditions of the soil in order to establish the dependence of yielding potential on the water amounts reaching the soil surface during the growing season. The four-replicate trail was set up according to the randomised complete-block design on chernozem. Pre-watering soil moisture was approximately 70% of field water capacity, and soil moisture was established thermogravimetrically. During the five-year studies, the following differences in yields could be as follows: 12.68 t ha-1 (ZP 341; 12.76 t ha-1 (ZP 434; 13.17 t ha-1 (ZP 578; 14.03 t ha-1 (ZP 684 and 13.75 t ha-1 (ZP 704 under conditions of 440 mm, 440 mm, 424 mm, 457 mm and 466 mm of water, respectively. The hybrid ZP 341, i.e. ZP 578 expressed the highest, i.e. the lowest tolerance in dry relative seasons, respectively. The reduction of the water amount for every 10 mm decreased the yield by 119.4 kg ha-1 (ZP 341, 156.7 kg ha-1 (ZP 434, 172.3 kg ha-1 (ZP 578, 148.9 kg ha-1 (ZP 684 and 151.1 kg ha-1 (ZP 704. [Projekat Ministarstva nauke Republike Srbije, br. TR 31037

  14. Root water uptake and lateral interactions among root systems in a temperate forest

    Science.gov (United States)

    Agee, E.; He, L.; Bisht, G.; Gough, C. M.; Couvreur, V.; Matheny, A. M.; Bohrer, G.; Ivanov, V. Y.

    2016-12-01

    A growing body of research has highlighted the importance of root architecture and hydraulic properties to the maintenance of the transpiration stream under water limitation and drought. Detailed studies of single plant systems have shown the ability of root systems to adjust zones of uptake due to the redistribution of local water potential gradients, thereby delaying the onset of stress under drying conditions. An open question is how lateral interactions and competition among neighboring plants impact individual and community resilience to water stress. While computational complexity has previously hindered the implementation of microscopic root system structure and function in larger scale hydrological models, newer hybrid approaches allow for the resolution of these properties at the plot scale. Using a modified version of the PFLOTRAN model, which represents the 3-D physics of variably saturated soil, we model root water uptake in a one-hectare temperate forest plot under natural and synthetic forcings. Two characteristic hydraulic architectures, tap roots and laterally sprawling roots, are implemented in an ensemble of simulations. Variations of root architecture, their hydraulic properties, and degree of system interactions produce variable local response to water limitation and provide insights on individual and community response to changing meteorological conditions. Results demonstrate the ability of interacting systems to shift areas of active uptake based on local gradients, allowing individuals to meet water demands despite competition from their peers. These results further illustrate how inter- and intra-species variations in root properties may influence not only individual response to water stress, but also help quantify the margins of resilience for forest ecosystems under changing climate.

  15. Water uptake by two river red gum ( Eucalyptus camaldulensis) clones in a discharge site plantation in the Western Australian wheatbelt

    Science.gov (United States)

    Marshall, John K.; Morgan, Anne L.; Akilan, Kandia; Farrell, Richard C. C.; Bell, David T.

    1997-12-01

    The heat-pulse technique was used to estimate year-long water uptake in a discharge zone plantation of 9-year-old clonal Eucalyptus camaldulensis Dehnh. near Wubin, Western Australia. Water uptake matched rainfall closely during weter months but exceeded rainfall as the dry season progressed. Average annual water uptake (1148 mm) exceeded rainfall (432 mm) by about 2.7 fold and approached 56% of pan evaporation for the area. The data suggest that at least 37% (i.e. ( {1}/{2.7}) × 100 ) of the lower catchment discharge zone should be planted to prevent the rise of groundwater. Water uptake varied with soil environment, season and genotype. Upslope trees used more water than did downslope trees. Water uptake was higher in E. camaldulensis clone M80 than in clone M66 until late spring. The difference reversed as summer progressed. Both clones, however, have the potential to dry out the landscape when potential evapotranspiration exceeds rainfall. This variation in water uptake within the species indicates the potential for manipulating plantation uptake by matching tree characteristics to site characteristics. Controlled experiments on the heat-pulse technique indicated accuracy errors of approximately 10%. This, combined with the ability to obtain long-term, continuous data and the superior logistics of use of the heat-pulse technique, suggests that results obtained by it would be much more reliable than those achieved by the ventilated chamber technique.

  16. 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...

  17. Protocols for atomistic modeling of water uptake into zeolite crystals for thermal storage and other applications

    International Nuclear Information System (INIS)

    Fasano, Matteo; Borri, Daniele; Chiavazzo, Eliodoro; Asinari, Pietro

    2016-01-01

    Highlights: • Numerical protocols for modeling water adsorption and infiltration into zeolite. • A priori screening of new materials for heat storage and desalination is possible. • Water uptake isotherms for bridging atomistic and engineering scales. - Abstract: We report numerical protocols for describing the water uptake process into microporous materials, with special emphasis on zeolite crystals. A better understanding and more predictive tools of the latter process are critical for a number of modern engineering applications, ranging from the optimization of loss free and compact thermal storage plants up to more efficient separation processes. Water sorption (and desorption) is indeed the key physical phenomenon to consider when designing several heat storage cycles, whereas water infiltration is to be studied when concerned with sieving through microporous materials for manufacturing selective membranes (e.g. water desalination by reverse osmosis). Despite the two quite different applications above, in this article we make an effort for illustrating a comprehensive numerical framework for predicting the engineering performances of microporous materials, based on detailed atomistic models. Thanks to the nowadays spectacular progresses in synthesizing an ever increasing number of new materials with desired properties such as zeolite with various concentrations of hydrophilic defects, we believe that the reported tools can possibly guide engineers in choosing and optimizing innovative materials for (thermal) engineering applications in the near future.

  18. Stone-ground wood pulp-reinforced polypropylene composites: Water uptake and thermal properties

    Directory of Open Access Journals (Sweden)

    Joan Pere López

    2012-11-01

    Full Text Available Two of the drawbacks of using natural-based composites in industrial applications are thermal instability and water uptake capacity. In this work, mechanical wood pulp was used to reinforce polypropylene at a level of 20 to 50 wt. %. Composites were mixed by means of a Brabender internal mixer for both non-coupled and coupled formulations. Differential scanning calorimetry (DSC and thermogravimetric analysis (TGA were used to determine the thermal properties of the composites. The water uptake behavior was evaluated by immersion of the composites in water until an equilibrium state was reached. Results of water absorption tests revealed that the amount of water absorption was clearly dependent upon the fiber content. The coupled composites showed lower water absorption compared to the uncoupled composites. The incorporation of mechanical wood pulp into the polypropylene matrix produced a clear nucleating effect by increasing the crystallinity degree of the polymer and also increasing the temperature of polymer degradation. The maximum degradation temperature for stone ground wood pulp–reinforced composites was in the range of 330 to 345 ºC.

  19. Changes in seed oil and protein contents of maize cultivars at different positions on the ear in response to water limitation

    Directory of Open Access Journals (Sweden)

    Kazem Ghassemi-Golezani

    2016-10-01

    Full Text Available A field experiment was carried out as split-split plot in 2014 to assess the effects of four irrigation treatments (irrigations after 60, 80, 100 and 120 mm evaporation, respectively on oil and protein changes of maize cultivars (SC704, NS640 and DC303: Late, mid and early maturing cultivars, respectively at different seed positions on the ear (upper, middle and lower positions on the ear. Overall, the highest seed yield was obtained from SC704, followed by NS640 and DC303 cultivars. Seed yield of all cultivars was higher at lower seed position on ear than at middle and upper parts of the ear under different irrigation treatments. The highest oil and protein yields were also recorded for seeds at lower position on the ear. Seed yield of all maize cultivars at various seed positions decreased with increasing irrigation intervals. Oil percentage decreased, but protein percentage increased with decreasing water availability. Water limitation decreased oil and protein yields of maize cultivars. Changes in protein and oil yields of maize cultivars at different seed positions and irrigation treatments were attributed to changes in seed yield.

  20. Tritiated water uptake kinetics in tissue-free water and organically-bound fractions of tomato plants

    International Nuclear Information System (INIS)

    Spencer, F.S.

    1984-03-01

    The kinetics of tritiated water (HTO) vapour uptake into tissue-free water tritium (TFWT) and organically bound tritium (OBT) fractions of tomato, Lycopersicon esculentum Mill., cv Vendor, were investigated under controlled growing conditions. Most uptake data fitted a first-order kinetic model, C t = C ∞ (1-e -kt ), where C t is the tritium concentration at time t, Ca the steady-state concentration and k the uptake rate constant. During atmospheric-HTO exposure with clean-water irrigation in open pots the TFWT k values were 0.024 ± 0.023 h -1 for new foliage, 0.104 ± 0.067 h -1 for old foliage and 0.042 ± to 0.136 h -1 for new green fruit. OBT uptake rate constants were 20 percent less for new foliage and 76 percent less for new green fruit. Under steady-state conditions the ratio of tritium specific activities of TWFT to atmospheric HTO were 0.43 in new foliage, 0.46 in old foliage and 0.19 in green fruit. Within the plant, OBT and TFWT ratios were 0.70 for new foliage, 0.63 for old foliage (maximum) and between 0.72 and 1.92 for green fruit. The greater than unity tritium specific activity ratios in green fruit were not attributed to tritium enrichment but rather to the translocation of foliar OBT to the growing fruit which contained lower specific activity TFWT derived from soil water

  1. Breeding for Increased Water Use Efficiency in Corn (Maize) Using a Low-altitude Unmanned Aircraft System

    Science.gov (United States)

    Shi, Y.; Veeranampalayam-Sivakumar, A. N.; Li, J.; Ge, Y.; Schnable, J. C.; Rodriguez, O.; Liang, Z.; Miao, C.

    2017-12-01

    Low-altitude aerial imagery collected by unmanned aircraft systems (UAS) at centimeter-level spatial resolution provides great potential to collect high throughput plant phenotyping (HTP) data and accelerate plant breeding. This study is focused on UAS-based HTP for breeding increased water use efficiency in corn in eastern Nebraska. The field trail is part of an effort by the Genomes to Fields consortium effort to grow and phenotype many of the same corn (maize) hybrids at approximately 40 locations across the United States and Canada in order to stimulate new research in crop modeling, the development of new plant phenotyping technologies and the identification of genetic loci that control the adaptation of specific corn (maize) lines to specific environments. It included approximately 250 maize hybrids primary generated using recently off patent material from major seed companies. These lines are the closest material to what farmers are growing today which can be legally used for research purposes and genotyped by the public sector. During the growing season, a hexacopter equipped with a multispectral and a RGB cameras was flown and used to image this 1-hectare field trial near Mead, NE. Sensor data from the UAS were correlated directly with grain yield, measured at the end of the growing season, and were also be used to quantify other traits of interest to breeders including flowering date, plant height, leaf orientation, canopy spectral, and stand count. The existing challenges of field data acquisition (to ensure data quality) and development of effective image processing algorithms (such as detecting corn tassels) will be discussed. The success of this study and others like it will speed up the process of phenotypic data collection, and provide more accurate and detailed trait data for plant biologists, plant breeders, and other agricultural scientists. Employing advanced UAS-based machine vision technologies in agricultural applications have the potential

  2. Multi-scale heterogeneity in the temporal origin of water taken up by trees water uptake inferred using stable isotopes

    Science.gov (United States)

    Allen, S. T.; Kirchner, J. W.; Braun, S.; Siegwolf, R. T.; Goldsmith, G. R.

    2017-12-01

    Xylem water isotopic composition can reveal how water moves through soil and is subsequently taken up by plants. By examining how xylem water isotopes vary across distinct climates and soils, we test how these site characteristics control critical-zone water movement and tree uptake. Xylem water was collected from over 900 trees at 191 sites across Switzerland during a 10-day period in mid-summer 2015. Sites contained oak, beech and/or spruce trees and ranged in elevation from 260 to 1870 m asl with mean annual precipitation from 700 to 2060 mm. Xylem water samples were analyzed for 2H and 18O using isotope ratio mass spectrometry. Patterns in the temporal origin of xylem water showed regional differences. For example, trees in the southern and alpine regions had xylem water isotopic signatures that more closely resembled summer precipitation. The isotopic spatial range observed for mid-summer xylem waters was similar to the seasonal range of precipitation; that is, mid-summer xylem water at some sites resembled summer precipitation, and at other sites resembled winter precipitation. Xylem water from spruces, oaks, and beeches at the same sites did not differ from each other, despite these species having different rooting habits. Across all sites and species, precipitation amount correlated positively with xylem δ18O. In higher-precipitation areas, summer rain apparently displaces or mixes with older (winter) stored waters, thus reducing the winter-water isotopic signal in xylem water. Alternatively, in areas with limited precipitation, xylem water more closely matched winter water, indicating greater use of older stored water. We conclude that regional variations in precipitation deficits determine variations in the turnover rate of plant-available soil water and storage.

  3. Gradients in microbial methanol uptake: productive coastal upwelling waters to oligotrophic gyres in the Atlantic Ocean

    Science.gov (United States)

    Dixon, Joanna L; Sargeant, Stephanie; Nightingale, Philip D; Colin Murrell, J

    2013-01-01

    Methanol biogeochemistry and its importance as a carbon source in seawater is relatively unexplored. We report the first microbial methanol carbon assimilation rates (k) in productive coastal upwelling waters of up to 0.117±0.002 d−1 (∼10 nmol l−1 d−1). On average, coastal upwelling waters were 11 times greater than open ocean northern temperate (NT) waters, eight times greater than gyre waters and four times greater than equatorial upwelling (EU) waters; suggesting that all upwelling waters upon reaching the surface (⩽20 m), contain a microbial population that uses a relatively high amount of carbon (0.3–10 nmol l−1 d−1), derived from methanol, to support their growth. In open ocean Atlantic regions, microbial uptake of methanol into biomass was significantly lower, ranging between 0.04–0.68 nmol l−1 d−1. Microbes in the Mauritanian coastal upwelling used up to 57% of the total methanol for assimilation of the carbon into cells, compared with an average of 12% in the EU, and 1% in NT and gyre waters. Several methylotrophic bacterial species were identified from open ocean Atlantic waters using PCR amplification of mxaF encoding methanol dehydrogenase, the key enzyme in bacterial methanol oxidation. These included Methylophaga sp., Burkholderiales sp., Methylococcaceae sp., Ancylobacter aquaticus, Paracoccus denitrificans, Methylophilus methylotrophus, Methylobacterium oryzae, Hyphomicrobium sp. and Methylosulfonomonas methylovora. Statistically significant correlations for upwelling waters between methanol uptake into cells and both chlorophyll a concentrations and methanol oxidation rates suggest that remotely sensed chlorophyll a images, in these productive areas, could be used to derive total methanol biological loss rates, a useful tool for atmospheric and marine climatically active gas modellers, and air–sea exchange scientists. PMID:23178665

  4. Studies on the traditional methods of production of maize tuwo (a ...

    African Journals Online (AJOL)

    African Journal of Food, Agriculture, Nutrition and Development ... on the quality characteristics of maize tuwo (a Nigerian nonfermented maize dumpling) ... The sequential mixing of flour and water during maize tuwo preparation should also ...

  5. Cyclic use of saline and non-saline water to increase water use efficiency and soil sustainability on drip irrigated maize in a semi-arid region

    International Nuclear Information System (INIS)

    Hassanli, M.; Ebrahimian, H.

    2016-01-01

    Use of saline water for irrigation is a strategy to mitigate water shortage. The objective of this study was to investigate the impact of the cyclic and constant use of saline and non-saline water on drip irrigated maize yield and irrigation water use efficiency (IWUE). Nine field treatments were laid out based on alternative irrigation management of non-saline and saline water combinations. The treatments were: two salinity levels of 3.5 and 5.7 dS/m and freshwater (0.4 dS/m) application in every one, three and five saline water application (1:1, 3:1 and 5:1, respectively). Results showed that the 1:1 combination management was the best in terms of crop yield and IWUE. In this treatment, salt concentration at the end of growing season was not significantly changed compared to its initial condition. If off-season precipitation or leaching was available, the 3:1 and 5:1 treatments were appropriated. Highest and lowest values of IWUE were 15.3 and 8.7 kg/m3 for the 1:1 management using water salinity of 3.5 dS/m and the treatment of constant irrigation with water salinity of 5.7 dS/m, respectively. Under low off-season precipitations, artificial leaching is essential for land sustainability in most treatments.

  6. Cyclic use of saline and non-saline water to increase water use efficiency and soil sustainability on drip irrigated maize in a semi-arid region

    Energy Technology Data Exchange (ETDEWEB)

    Hassanli, M.; Ebrahimian, H.

    2016-07-01

    Use of saline water for irrigation is a strategy to mitigate water shortage. The objective of this study was to investigate the impact of the cyclic and constant use of saline and non-saline water on drip irrigated maize yield and irrigation water use efficiency (IWUE). Nine field treatments were laid out based on alternative irrigation management of non-saline and saline water combinations. The treatments were: two salinity levels of 3.5 and 5.7 dS/m and freshwater (0.4 dS/m) application in every one, three and five saline water application (1:1, 3:1 and 5:1, respectively). Results showed that the 1:1 combination management was the best in terms of crop yield and IWUE. In this treatment, salt concentration at the end of growing season was not significantly changed compared to its initial condition. If off-season precipitation or leaching was available, the 3:1 and 5:1 treatments were appropriated. Highest and lowest values of IWUE were 15.3 and 8.7 kg/m3 for the 1:1 management using water salinity of 3.5 dS/m and the treatment of constant irrigation with water salinity of 5.7 dS/m, respectively. Under low off-season precipitations, artificial leaching is essential for land sustainability in most treatments.

  7. Lipid–water partition coefficients and correlations with uptakes by algae of organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Hung, Wei-Nung [Green Energy and Environment Research Laboratories, Industrial Technology Research Institute, Hsinchu 30011, Taiwan (China); Chiou, Cary T., E-mail: carychio@mail.ncku.edu.tw [Department of Environmental Engineering and Sustainable Environment Research Laboratory, National Cheng Kung University, Tainan 70101, Taiwan (China); U.S. Geological Survey, Denver Federal Center, Denver, CO 80225 (United States); Lin, Tsair-Fuh, E-mail: tflin@mail.ncku.edu.tw [Department of Environmental Engineering and Sustainable Environment Research Laboratory, National Cheng Kung University, Tainan 70101, Taiwan (China)

    2014-08-30

    Graphical abstract: - Highlights: • Partition coefficients of contaminants with lipid triolein (K{sub tw}) are measured. • Measured K{sub tw} values are nearly the same as the respective K{sub ow}. • Sorption of the contaminants to a dry algal powder is similarly measured. • Algal uptake of a compound occurs primarily by partition into the algal lipid. - Abstract: In view of the scarcity of the lipid–water partition coefficients (K{sub tw}) for organic compounds, the log K{sub tw} values for many environmental contaminants were measured using ultra-pure triolein as the model lipid. Classes of compounds studied include alkyl benzenes, halogenated benzenes, short-chain chlorinated hydrocarbons, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and organochlorine pesticides. In addition to log K{sub tw} determination, the uptakes of these compounds from water by a dry algal species were measured to evaluate the lipid effect on the algal uptake. The measured log K{sub tw} are closely related to their respective log K{sub ow} (octanol–water), with log K{sub ow} = 1.9 to 6.5. A significant difference is observed between the present and early measured log K{sub tw} for compounds with log K{sub ow} > ∼5, which is attributed to the presence and absence of a triolein microemulsion in water affecting the solute partitioning. The observed lipid-normalized algae–water distribution coefficients (log K{sub aw/lipid}) are virtually identical to the respective log K{sub tw} values, which manifests the dominant lipid-partition effect of the compounds with algae.

  8. Cadmium triggers Elodea canadensis to change the surrounding water pH and thereby Cd uptake.

    Science.gov (United States)

    Javed, M Tariq; Greger, Maria

    2011-01-01

    This study was aimed to investigate the influence of Elodea canadensis shoots on surrounding water pH in the presence of cadmium and the effect of plant-induced pH on cadmium uptake. The pH change in the surrounding nutrient solution and Cd uptake by Elodea shoots were investigated after cultivation of various plant densities (1, 3, 6 plants per 500 ml) in hydroponics at a starting pH of 4.0 and in the presence of different concentrations of cadmium (0, 0.1, 0.5 microM). Cadmium uptake was also investigated at different constant pH (4.0, 4.5, 5.5 and 6.5). To investigate if the pH change arose from photosynthetic activities, plants were grown under light, darkness or in the presence of a photosynthetic inhibitor, 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), and 0.5 microM cadmium in the solution. Elodea had an ability to increase the surrounding water pH, when the initial pH was low, which resulted in increased accumulation of Cd. The higher the plant density, the more pronounced was the pH change. The pH increase was not due to the photosynthetic activity since the pH rise was more pronounced under darkness and in the presence of DCMU. The pH increase by Elodea was triggered by cadmium.

  9. Cold induced changes in the water balance affect immunocytolocalization pattern of one of the aquaporins in the vascular system in the leaves of maize (Zea mays L.).

    Science.gov (United States)

    Bilska-Kos, Anna; Szczepanik, Jarosław; Sowiński, Paweł

    2016-10-20

    Chilling stress is known to affect the water balance in plants, which often manifests itself in the decrease of the water potential in different organs. Relationships between chilling, assimilate transport and water balance are far from being understood. Although aquaporins play a key role in regulating water balance in plants, especially under stress conditions, the role of individual aquaporins in stress response remains unclear. In this report we show the specific localization within plasma membranes of one of the aquaporins (PIP2;3) in the leaves of two maize inbred lines differing in their chilling-sensitivity. This form of aquaporin has been also observed in thick-walled sieve elements - an additional type of sieve tubes of unclear function found only in monocotyledons. Moderate chilling (about 15°C) caused significant reduction of labelling in these cells accompanied by a steep decrease in the water potential in leaves of chilling-sensitive maize line. Our results suggest that both PIP2;3 and thick-walled sieve tubes may be an unknown element of the mechanism of the response of maize to cold stress. Copyright © 2016 Elsevier GmbH. All rights reserved.

  10. Effect of water management and silicon on germination, growth, phosphorus and arsenic uptake in rice.

    Science.gov (United States)

    Zia, Zahida; Bakhat, Hafiz Faiq; Saqib, Zulfiqar Ahmad; Shah, Ghulam Mustafa; Fahad, Shah; Ashraf, Muhammad Rizwan; Hammad, Hafiz Mohkum; Naseem, Wajid; Shahid, Muhammad

    2017-10-01

    Silicon (Si) is the 2nd most abundant element in soil which is known to enhance stress tolerance in wide variety of crops. Arsenic (As), a toxic metalloid enters into the human food chain through contaminated water and food or feed. To alleviate the deleterious effect of As on human health, it is a need of time to find out an effective strategy to reduce the As accumulation in the food chain. The experiments were conducted during September-December 2014, and 2016 to optimize Si concentration for rice (Oryza sativa L.) exposed to As stress. Further experiment were carried out to evaluate the effect of optimum Si on rice seed germination, seedling growth, phosphorus and As uptake in rice plant. During laboratory experiment, rice seeds were exposed to 150 and 300µM As with and without 3mM Si supplementation. Results revealed that As application, decreased the germination up to 40-50% as compared to control treatment. Arsenic stress also significantly (P management, significantly (P˂0.05) affected the plant growth, Si and As concentrations in the plant. Arsenic uptake was relatively less under aerobic conditions. The maximum As concentration (9.34 and 27.70mgkg DW -1 in shoot and root, respectively) was found in plant treated with 300µM As in absence of Si under anaerobic condition. Similarly, anaerobic condition resulted in higher As uptake in the plants. The study demonstrated that aerobic cultivation is suitable to decrease the As uptake and in rice exogenous Si supply is beneficial to decrease As uptake under both anaerobic and aerobic conditions. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Ozone uptake, water loss and carbon exchange dynamics in annually drought-stressed Pinus ponderosa forests: measured trends and parameters for uptake modeling.

    Science.gov (United States)

    Panek, Jeanne A

    2004-03-01

    This paper describes 3 years of physiological measurements on ponderosa pine (Pinus ponderosa Dougl. ex Laws.) growing along an ozone concentration gradient in the Sierra Nevada, California, including variables necessary to parameterize, validate and modify photosynthesis and stomatal conductance algorithms used to estimate ozone uptake. At all sites, gas exchange was under tight stomatal control during the growing season. Stomatal conductance was strongly correlated with leaf water potential (R2=0.82), which decreased over the growing season with decreasing soil water content (R2=0.60). Ozone uptake, carbon uptake, and transpirational water loss closely followed the dynamics of stomatal conductance. Peak ozone and CO2 uptake occurred in early summer and declined progressively thereafter. As a result, periods of maximum ozone uptake did not correspond to periods of peak ozone concentration, underscoring the inappropriateness of using current metrics based on concentration (e.g., SUM0, W126 and AOT40) for assessing ozone exposure risk to plants in this climate region. Both Jmax (maximum CO2-saturated photosynthetic rate, limited by electron transport) and Vcmax (maximum rate of Rubisco-limited carboxylation) increased toward the middle of the growing season, then decreased in September. Intrinsic water-use efficiency rose with increasing drought stress, as expected. The ratio of Jmax to Vcmax was similar to literature values of 2.0. Nighttime respiration followed a Q10 of 2.0, but was significantly higher at the high-ozone site. Respiration rates decreased by the end of the summer as a result of decreased metabolic activity and carbon stores.

  12. Water management options based on rainfall analysis for rainfed maize (Zea Mays L.) production in Rushinga district Zimbabwe

    NARCIS (Netherlands)

    Nyakudya, I.W.; Stroosnijder, L.

    2011-01-01

    Maize (Zea mays L.), the dominant and staple food crop in Southern and Eastern Africa, is preferred to the drought-tolerant sorghum and pearl millet even in semi-arid areas. In semi-arid areas production of maize is constrained by droughts and poor rainfall distribution. The best way to grow crops

  13. Visualization of root water uptake: quantification of deuterated water transport in roots using neutron radiography and numerical modeling.

    Science.gov (United States)

    Zarebanadkouki, Mohsen; Kroener, Eva; Kaestner, Anders; Carminati, Andrea

    2014-10-01

    Our understanding of soil and plant water relations is limited by the lack of experimental methods to measure water fluxes in soil and plants. Here, we describe a new method to noninvasively quantify water fluxes in roots. To this end, neutron radiography was used to trace the transport of deuterated water (D2O) into roots. The results showed that (1) the radial transport of D2O from soil to the roots depended similarly on diffusive and convective transport and (2) the axial transport of D2O along the root xylem was largely dominated by convection. To quantify the convective fluxes from the radiographs, we introduced a convection-diffusion model to simulate the D2O transport in roots. The model takes into account different pathways of water across the root tissue, the endodermis as a layer with distinct transport properties, and the axial transport of D2O in the xylem. The diffusion coefficients of the root tissues were inversely estimated by simulating the experiments at night under the assumption that the convective fluxes were negligible. Inverse modeling of the experiment at day gave the profile of water fluxes into the roots. For a 24-d-old lupine (Lupinus albus) grown in a soil with uniform water content, root water uptake was higher in the proximal parts of lateral roots and decreased toward the distal parts. The method allows the quantification of the root properties and the regions of root water uptake along the root systems. © 2014 American Society of Plant Biologists. All Rights Reserved.

  14. Bacterial polyextremotolerant bioemulsifiers from arid soils improve water retention capacity and humidity uptake in sandy soil

    KAUST Repository

    Raddadi, Noura; Giacomucci, Lucia; Marasco, Ramona; Daffonchio, Daniele; Cherif, Ameur; Fava, Fabio

    2018-01-01

    Water stress is a critical issue for plant growth in arid sandy soils. Here, we aimed to select bacteria producing polyextremotolerant surface-active compounds capable of improving water retention and humidity uptake in sandy soils.From Tunisian desert and saline systems, we selected eleven isolates able to highly emulsify different organic solvents. The bioemulsifying activities were stable with 30% NaCl, at 4 and 120 °C and in a pH range 4-12. Applications to a sandy soil of the partially purified surface-active compounds improved soil water retention up to 314.3% compared to untreated soil. Similarly, after 36 h of incubation, the humidity uptake rate of treated sandy soil was up to 607.7% higher than untreated controls.Overall, results revealed that polyextremotolerant bioemulsifiers of bacteria from arid and desert soils represent potential sources to develop new natural soil-wetting agents for improving water retention in arid soils.

  15. Bacterial polyextremotolerant bioemulsifiers from arid soils improve water retention capacity and humidity uptake in sandy soil.

    Science.gov (United States)

    Raddadi, Noura; Giacomucci, Lucia; Marasco, Ramona; Daffonchio, Daniele; Cherif, Ameur; Fava, Fabio

    2018-05-31

    Water stress is a critical issue for plant growth in arid sandy soils. Here, we aimed to select bacteria producing polyextremotolerant surface-active compounds capable of improving water retention and humidity uptake in sandy soils. From Tunisian desert and saline systems, we selected eleven isolates able to highly emulsify different organic solvents. The bioemulsifying activities were stable with 30% NaCl, at 4 and 120 °C and in a pH range 4-12. Applications to a sandy soil of the partially purified surface-active compounds improved soil water retention up to 314.3% compared to untreated soil. Similarly, after 36 h of incubation, the humidity uptake rate of treated sandy soil was up to 607.7% higher than untreated controls. Overall, results revealed that polyextremotolerant bioemulsifiers of bacteria from arid and desert soils represent potential sources to develop new natural soil-wetting agents for improving water retention in arid soils.

  16. Bacterial polyextremotolerant bioemulsifiers from arid soils improve water retention capacity and humidity uptake in sandy soil

    KAUST Repository

    Raddadi, Noura

    2018-05-31

    Water stress is a critical issue for plant growth in arid sandy soils. Here, we aimed to select bacteria producing polyextremotolerant surface-active compounds capable of improving water retention and humidity uptake in sandy soils.From Tunisian desert and saline systems, we selected eleven isolates able to highly emulsify different organic solvents. The bioemulsifying activities were stable with 30% NaCl, at 4 and 120 °C and in a pH range 4-12. Applications to a sandy soil of the partially purified surface-active compounds improved soil water retention up to 314.3% compared to untreated soil. Similarly, after 36 h of incubation, the humidity uptake rate of treated sandy soil was up to 607.7% higher than untreated controls.Overall, results revealed that polyextremotolerant bioemulsifiers of bacteria from arid and desert soils represent potential sources to develop new natural soil-wetting agents for improving water retention in arid soils.

  17. Simulating the impact of no-till systems on field water fluxes and maize productivity under semi-arid conditions

    Science.gov (United States)

    Mupangwa, W.; Jewitt, G. P. W.

    Crop output from the smallholder farming sector in sub-Saharan Africa is trailing population growth leading to widespread household food insecurity. It is therefore imperative that crop production in semi-arid areas be improved in order to meet the food demand of the ever increasing human population. No-till farming practices have the potential to increase crop productivity in smallholder production systems of sub-Saharan Africa, but rarely do because of the constraints experienced by these farmers. One of the most significant of these is the consumption of mulch by livestock. In the absence of long term on-farm assessment of the no-till system under smallholder conditions, simulation modelling is a tool that provides an insight into the potential benefits and can highlight shortcomings of the system under existing soil, climatic and socio-economic conditions. Thus, this study was designed to better understand the long term impact of no-till system without mulch cover on field water fluxes and maize productivity under a highly variable rainfall pattern typical of semi-arid South Africa. The simulated on-farm experiment consisted of two tillage treatments namely oxen-drawn conventional ploughing (CT) and ripping (NT). The APSIM model was applied for a 95 year period after first being calibrated and validated using measured runoff and maize yield data. The predicted results showed significantly higher surface runoff from the conventional system compared to the no-till system. Predicted deep drainage losses were higher from the NT system compared to the CT system regardless of the rainfall pattern. However, the APSIM model predicted 62% of the annual rainfall being lost through soil evaporation from both tillage systems. The predicted yields from the two systems were within 50 kg ha -1 difference in 74% of the years used in the simulation. In only 9% of the years, the model predicted higher grain yield in the NT system compared to the CT system. It is suggested that

  18. Water uptake and transport in lianas and co-occurring trees of a seasonally dry tropical forest.

    Science.gov (United States)

    José Luis Andrade; Frederick C. Meinzer; Guillermo Goldstein; Stefan A. Schnitzer

    2005-01-01

    Water uptake and transport were studied in eight liana species in a seasonally dry tropical forest on Barro Colorado Island, Panama. Stable hydrogen isotope composition (δD) of xylem and soil water, soil volumetric water content (θv), and basal sap flow were measured during the 1997 and...

  19. Utilization of Landsat-8 data for the estimation of carrot and maize crop water footprint under the arid climate of Saudi Arabia.

    Science.gov (United States)

    Madugundu, Rangaswamy; Al-Gaadi, Khalid A; Tola, ElKamil; Hassaballa, Abdalhaleem A; Kayad, Ahmed G

    2018-01-01

    The crop Water Footprint (WF) can provide a comprehensive knowledge of the use of water through the demarcation of the amount of the water consumed by different crops. The WF has three components: green (WFg), blue (WFb) and grey (WFgr) water footprints. The WFg refers to the rainwater stored in the root zone soil layer and is mainly utilized for agricultural, horticultural and forestry production. The WFb, however, is the consumptive use of water from surface or groundwater resources and mainly deals with irrigated agriculture, industry, domestic water use, etc. While the WFgr is the amount of fresh water required to assimilate pollutants resulting from the use of fertilizers/agrochemicals. This study was conducted on six agricultural fields in the Eastern region of Saudi Arabia, during the period from December 2015 to December 2016, to investigate the spatiotemporal variation of the WF of silage maize and carrot crops. The WF of each crop was estimated in two ways, namely agro-meteorological (WFAgro) and remote sensing (WFRS) methods. The blue, green and grey components of WFAgro were computed with the use of weather station/Eddy covariance measurements and field recorded crop yield datasets. The WFRS estimated by applying surface energy balance principles on Landsat-8 imageries. However, due to non-availability of Landsat-8 data on the event of rainy days, this study was limited to blue component (WFRS-b). The WFAgro of silage maize was found to range from 3545 m3 t-1 to 4960 m3 t-1; on an average, the WFAgro-g, WFAgro-b, and WFAgro-gr are composed of < 1%, 77%, and 22%, respectively. In the case of carrot, the WFAgro ranged between 297 m3 t-1 and 502 m3 t-1. The WFAgro-g of carrot crop was estimated at <1%, while WFAgro-b and WFAgro-gr was 67% and 32%, respectively. The WFAgro-b is occupied as a major portion in WF of silage maize (77%) and carrot (68%) crops. This is due to the high crop water demand combined with a very erratic rainfall, the irrigation is

  20. Utilization of Landsat-8 data for the estimation of carrot and maize crop water footprint under the arid climate of Saudi Arabia.

    Directory of Open Access Journals (Sweden)

    Rangaswamy Madugundu

    Full Text Available The crop Water Footprint (WF can provide a comprehensive knowledge of the use of water through the demarcation of the amount of the water consumed by different crops. The WF has three components: green (WFg, blue (WFb and grey (WFgr water footprints. The WFg refers to the rainwater stored in the root zone soil layer and is mainly utilized for agricultural, horticultural and forestry production. The WFb, however, is the consumptive use of water from surface or groundwater resources and mainly deals with irrigated agriculture, industry, domestic water use, etc. While the WFgr is the amount of fresh water required to assimilate pollutants resulting from the use of fertilizers/agrochemicals. This study was conducted on six agricultural fields in the Eastern region of Saudi Arabia, during the period from December 2015 to December 2016, to investigate the spatiotemporal variation of the WF of silage maize and carrot crops. The WF of each crop was estimated in two ways, namely agro-meteorological (WFAgro and remote sensing (WFRS methods. The blue, green and grey components of WFAgro were computed with the use of weather station/Eddy covariance measurements and field recorded crop yield datasets. The WFRS estimated by applying surface energy balance principles on Landsat-8 imageries. However, due to non-availability of Landsat-8 data on the event of rainy days, this study was limited to blue component (WFRS-b. The WFAgro of silage maize was found to range from 3545 m3 t-1 to 4960 m3 t-1; on an average, the WFAgro-g, WFAgro-b, and WFAgro-gr are composed of < 1%, 77%, and 22%, respectively. In the case of carrot, the WFAgro ranged between 297 m3 t-1 and 502 m3 t-1. The WFAgro-g of carrot crop was estimated at <1%, while WFAgro-b and WFAgro-gr was 67% and 32%, respectively. The WFAgro-b is occupied as a major portion in WF of silage maize (77% and carrot (68% crops. This is due to the high crop water demand combined with a very erratic rainfall, the

  1. Worldwide data sets constrain the water vapor uptake coefficient in cloud formation.

    Science.gov (United States)

    Raatikainen, Tomi; Nenes, Athanasios; Seinfeld, John H; Morales, Ricardo; Moore, Richard H; Lathem, Terry L; Lance, Sara; Padró, Luz T; Lin, Jack J; Cerully, Kate M; Bougiatioti, Aikaterini; Cozic, Julie; Ruehl, Christopher R; Chuang, Patrick Y; Anderson, Bruce E; Flagan, Richard C; Jonsson, Haflidi; Mihalopoulos, Nikos; Smith, James N

    2013-03-05

    Cloud droplet formation depends on the condensation of water vapor on ambient aerosols, the rate of which is strongly affected by the kinetics of water uptake as expressed by the condensation (or mass accommodation) coefficient, αc. Estimates of αc for droplet growth from activation of ambient particles vary considerably and represent a critical source of uncertainty in estimates of global cloud droplet distributions and the aerosol indirect forcing of climate. We present an analysis of 10 globally relevant data sets of cloud condensation nuclei to constrain the value of αc for ambient aerosol. We find that rapid activation kinetics (αc > 0.1) is uniformly prevalent. This finding resolves a long-standing issue in cloud physics, as the uncertainty in water vapor accommodation on droplets is considerably less than previously thought.

  2. Phenomics allows identification of genomic regions affecting maize stomatal conductance with conditional effects of water deficit and evaporative demand.

    Science.gov (United States)

    Prado, Santiago Alvarez; Cabrera-Bosquet, Llorenç; Grau, Antonin; Coupel-Ledru, Aude; Millet, Emilie J; Welcker, Claude; Tardieu, François

    2018-02-01

    Stomatal conductance is central for the trades-off between hydraulics and photosynthesis. We aimed at deciphering its genetic control and that of its responses to evaporative demand and water deficit, a nearly impossible task with gas exchanges measurements. Whole-plant stomatal conductance was estimated via inversion of the Penman-Monteith equation from data of transpiration and plant architecture collected in a phenotyping platform. We have analysed jointly 4 experiments with contrasting environmental conditions imposed to a panel of 254 maize hybrids. Estimated whole-plant stomatal conductance closely correlated with gas-exchange measurements and biomass accumulation rate. Sixteen robust quantitative trait loci (QTLs) were identified by genome wide association studies and co-located with QTLs of transpiration and biomass. Light, vapour pressure deficit, or soil water potential largely accounted for the differences in allelic effects between experiments, thereby providing strong hypotheses for mechanisms of stomatal control and a way to select relevant candidate genes among the 1-19 genes harboured by QTLs. The combination of allelic effects, as affected by environmental conditions, accounted for the variability of stomatal conductance across a range of hybrids and environmental conditions. This approach may therefore contribute to genetic analysis and prediction of stomatal control in diverse environments. © 2017 John Wiley & Sons Ltd.

  3. Water Uptake By Mars Salt Analogs: An Investigation Of Stable Aqueous Solutions On Mars Using Raman Microscopy

    Science.gov (United States)

    Nuding, D.; Gough, R. V.; Jorgensen, S. K.; Tolbert, M. A.

    2013-12-01

    To understand the formation of briny aqueous solutions on Mars, a salt analog was developed to closely match the individual cation and anion concentrations as reported by the Wet Chemistry Laboratory aboard the Phoenix Lander. ';Instant Mars' is a salt analog developed to fully encompass the correct concentrations of magnesium, calcium, potassium, sodium, perchlorate, chloride, and sulfate ions. Using environmental Raman microscopy, we have studied the water uptake by the Instant Mars analog as a function of temperature and relative humidity. Water uptake was monitored using Raman spectroscopy in combination with optical microscopy. A MicroJet droplet generator was used to generate 30 μm diameter particles that were deposited onto a quartz disc. The particles undergo visual transformations as the relative humidity (RH) is increased and the presence of water uptake is confirmed by Raman spectroscopy. At -30° C, water uptake begins at ~ 35% RH as humidity is increased. The water uptake is marked by the growth of a sulfate peak at 990 cm-1, an indicator that sulfate has undergone a phase transition into an aqueous state. As the RH continues to increase, the peak in the O-H region (~3500 cm-1) broadens as more liquid water accumulates in the particles. The Instant Mars particles achieve complete deliquescence at 68% RH, indicated both visually and with Raman spectroscopy. The gradual water uptake observed suggests that deliquescence of the Instant Mars particles is not an immediate process, but that it occurs in steps marked by the deliquescence of the individual salts. Perhaps of even more significance is the tendency for the Instant Mars particles to remain aqueous at low humidity as RH is decreased. Raman spectra indicate that liquid water is present as low as 2% RH at -30° C. Ongoing work will examine the phase of Instant Mars particles under simulated Martian surface and subsurface conditions to gain insight into the possibility for aqueous solutions on Mars

  4. The uptake of radiationless by some fresh water aquatic biota review

    International Nuclear Information System (INIS)

    Abdel Malik, W.E.Y.; Ibrahim, A.S.; El-Shinawy, R.M.K.

    2005-01-01

    The work presented in this paper reviews many studies carried out by the authors along the last thirty years. The behaviour of the radionuclides in the aquatic ecology of Ismailia Canal stream is of great interest for the evaluation of the possible hazards that may occur to man through the movement of such radionuclides via food chain. Laboratory investigations have been carried out in order to understand the accumulation and release of some radionuclide by some aquatic biota (aquatic macrophyte aquatic plants, some snails species and some fish species) inhabiting this fresh water stream. Different parameters such as water ph, contact time, water salinity, etc. were used in these investigations. The kinetic analysis of the uptake process of some radio nuclides by certain biota was performed. From this analysis, it was possible (through the statistical methods) to investigate that the uptake process proceeded through different steps with different rates depending on the radionuclide and the biota species. It was possible to conclude that some of the selected biota can be used as biological indicators for certain radionuclides

  5. Balancing Water Uptake and Loss through the Coordinated Regulation of Stomatal and Root Development.

    Directory of Open Access Journals (Sweden)

    Christopher Hepworth

    Full Text Available Root development is influenced by nutrient and water availabilities. Plants are able to adjust many attributes of their root in response to environmental signals including the size and shape of the primary root, lateral roots and root hairs. Here we investigated the response of roots to changes in the levels of leaf transpiration associated with altered stomatal frequency. We found that plants with high stomatal density and conductance produce a larger rooting area and as a result have enhanced phosphate uptake capacity whereas plants with low stomatal conductance produce a smaller root. Manipulating the growth environment of plants indicated that enhanced root growth is most likely a result of an increased demand for water rather than phosphate. Plants manipulated to have an increase or reduction in root hair growth show a reduction or increase respectively, in stomatal conductance and density. Our results demonstrate that plants can balance their water uptake and loss through coordinated regulation of both stomatal and root development.

  6. Uptake of Mn and Cd by Wild Water Spinach and Their Bioaccumulation and Translocation Factors

    Directory of Open Access Journals (Sweden)

    Billy Teck Huat Guan

    2017-01-01

    Full Text Available Polluted ponds and lakes close to agricultural activities become the exposure route of manganese (Mn and cadmium (Cd to aquatic plants in near vicinity. Therefore, a study of the uptake, bioaccumulation, and translocation of Mn and Cd by the water spinach (Ipomoea aquatica is presented in this paper. Different concentrations of Mn and Cd were added to the hydroponic nutrient solution that was used to grow the plants for the heavy metal uptake experiment under greenhouse conditions. The plant samples exposed to heavy metals were collected to determine the metal concentrations using atomic absorption spectroscopy (AAS and the metal concentrations were found for Mn was between 1.589 to 9.696 µg/g and Cd from 5.309 to 10.947 µg/g. The correlation and regression results showed that the water-to-shoot bioaccumulation factor (BAF decreased for Mn, while root-to-shoot translocation factor (TF values increased in the order Cd > Mn to the increasing levels of metals in the water. Furthermore, it was revealed from the two-way analysis of variance (ANOVA that the different metal types influenced the BAF and TF values at different metal concentration treatments.

  7. Sensible heat balance measurements of soil water evaporation beneath a maize canopy

    Science.gov (United States)

    Soil water evaporation is an important component of the water budget in a cropped field. Few methods are available for continuous and independent measurement of soil water evaporation. A sensible heat balance (SHB) approach has recently been demonstrated for continuously determining soil water evapo...

  8. NIRS determination of non-structural carbohydrates, water soluble carbohydrates and other nutritive quality traits in whole plant maize with wide range variability

    OpenAIRE

    L. Campo; A. B. Monteagudo; B. Salleres; P. Castro; J. Moreno-Gonzalez

    2013-01-01

    The aim of this work was to study the potential of near-infrared reflectance spectroscopy (NIRS) to predict non-structural carbohydrates (NSC), water soluble carbohydrates (WSC), in vitro organic dry matter digestibility (IVOMD), organic matter (OM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and starch in samples of whole plant maize with a wide range of variability. The samples were analyzed in reflectance mode by a spectrophotometer FOSS NIRSystems 6500. ...

  9. Effect of interfacial composition on uptake of curcumin-piperine mixtures in oil in water emulsions by Caco-2 cells.

    Science.gov (United States)

    Gülseren, İbrahim; Guri, Anilda; Corredig, Milena

    2014-06-01

    Encapsulation in lipid particles is often proposed as a solution to improve curcumin bioavailability. This bioactive molecule has low water solubility and rapidly degrades during digestion. In the present study, the uptake of curcumin from oil in water emulsions, prepared with two different emulsifiers, Tween 20 and Poloxamer 407, was investigated to determine the effect of interfacial composition on absorption. Piperine was added to the curcumin to limit the degradation of curcumin because it is known to inhibit β-glucuronidase activity. The emulsions were administered to Caco-2 cell cultures, which is used as a model for intestinal uptake, and the recovery of curcumin was measured. The curcumin uptake was significantly affected by the type of interface, and the extent of curcumin uptake improved significantly by piperine addition only in the case of oil-in-water emulsions stabilized by Poloxamer 407. This work provides further evidence of the importance of interfacial composition on the delivery of bioactives.

  10. Calcium uptake by cowpea as influenced by mycorrhizal colonization and water stress

    International Nuclear Information System (INIS)

    Pai, G.; Bagyaraj, D.J.; Padmavathi Ravindra, T.; Prasad, T.G.

    1994-01-01

    The role of vesicular-arbuscular mycorrhizal (VAM) colonization on calcium uptake was studied under different levels of moisture stress. Pots maintained at different moisture levels were given water containing known amount of radioactive calcium. The radioactivity in different parts of the plant was assessed 60 h after giving 45 Ca to the soil. High 45 Ca activity was present in all parts of vesicular-arbuscular mycrrohizal (VAM) plants compared to non-mycorrhizal plants at all levels of moisture stress. (author). 14 refs., 1 tab

  11. The effect of water deficit stress and nitrogen fertilizer levels on morphology traits, yield and leaf area index in maize

    International Nuclear Information System (INIS)

    Moosavi, S.G.

    2012-01-01

    In order to study the effect of water deficit stress at different growth stages and N fertilizer levels on morphological traits, yield and yield components of maize cv. Single Cross 704, an experiment was conducted as a split-plot based on a Randomized Complete Block Design with three replications. The main plot included irrigation at four levels (irrigation stop at 10-leaf, tasselling and grain-filling stages and optimum irrigation) and the sub-plot was N fertilizer at three levels (75, 150 and 225 kg N/ha). The results of analysis of variance showed that water-deficit stress and N fertilizer level significantly affected leaf area index at silking stage, ear length, grain number per ear, 1000-grain weight and grain yield. Stem diameter, ear diameter and harvest index were only affected by irrigation treatments and the interaction between irrigation and N level did not significantly affect the studied traits. Means comparison indicated that ear diameter under optimum irrigation was higher than that under the treatments of irrigation stop at 8-leaf, tasselling and grain-filling stages by 29.9, 19.1 and 33.5%, respectively; and ear length was higher than them by 38.1, 28.9 and 25.2%, respectively. Moreover, the highest grain number per ear, 1000-grain weight and grain yield were obtained under optimum irrigation treatment, and irrigation stop at 10-leaf, tasselling and grain-filling stages decreased grain yield by 52.8, 66.4 and 44.9%, respectively; and it decreased grain number/ear by 45.9, 59.3 and 30.1%, respectively. In addition, optimum irrigation treatment with mean 1000-grain weight of 289.2 g was significantly superior over other irrigation stop treatments by 27.6-42.8% and produced the highest leaf area index at silking stage (4.1). Means comparison of traits at different N levels indicated that N level of 225 kg/ha produced the highest ear length (17.82 cm), grain number per ear (401.9), 1000-grain weight (258.8 g), leaf area index at silking stage (4

  12. Compound Synthesis or Growth and Development of Roots/Stomata Regulate Plant Drought Tolerance or Water Use Efficiency/Water Uptake Efficiency.

    Science.gov (United States)

    Meng, Lai-Sheng

    2018-04-11

    Water is crucial to plant growth and development because it serves as a medium for all cellular functions. Thus, the improvement of plant drought tolerance or water use efficiency/water uptake efficiency is important in modern agriculture. In this review, we mainly focus on new genetic factors for ameliorating drought tolerance or water use efficiency/water uptake efficiency of plants and explore the involvement of these genetic factors in the regulation of improving plant drought tolerance or water use efficiency/water uptake efficiency, which is a result of altered stomata density and improving root systems (primary root length, hair root growth, and lateral root number) and enhanced production of osmotic protectants, which is caused by transcription factors, proteinases, and phosphatases and protein kinases. These results will help guide the synthesis of a model for predicting how the signals of genetic and environmental stress are integrated at a few genetic determinants to control the establishment of either water use efficiency or water uptake efficiency. Collectively, these insights into the molecular mechanism underpinning the control of plant drought tolerance or water use efficiency/water uptake efficiency may aid future breeding or design strategies to increase crop yield.

  13. Validation of a spatial–temporal soil water movement and plant water uptake model

    KAUST Repository

    HEPPELL, J.; PAYVANDI, S.; ZYGALAKIS, K.C.; SMETHURST, J.; FLIEGE, J.; ROOSE, T.

    2014-01-01

    © 2014, (publisher). All rights reserved. Management and irrigation of plants increasingly relies on accurate mathematical models for the movement of water within unsaturated soils. Current models often use values for water content and soil

  14. Nuclear magnetic resonance relaxation characterisation of water status of developing grains of maize (Zea mays L.) grown at different nitrogen levels.

    Science.gov (United States)

    Krishnan, Prameela; Chopra, Usha Kiran; Verma, Ajay Pal Singh; Joshi, Devendra Kumar; Chand, Ishwar

    2014-04-01

    Changes in water status of developing grains of maize (Zea mays L.) grown under different nitrogen levels were characterized by nuclear magnetic resonance (NMR) spectroscopy. There were distinct changes in water status of grains due to the application of different levels of nitrogen (0, 120 and 180 kg N ha(-1)). A comparison of the grain developmental characteristics, composition and physical properties indicated that, not only the developmental characteristics like grain weight, grain number/ear, and rate of grain filling increased, but also bound water characterized by the T2 component of NMR relaxation increased with nitrogen application (50-70%) and developmental stages leading to maturation (10-60%). The consistency in the patterns of responses to free water and intermediate water to increasing levels of nitrogen application and grain maturity suggested that nitrogen application resulted in more proportion of water to both bound- and intermediate states and less in free state. These changes are further corroborated by the concomitant increases in protein and starch contents in grains from higher nitrogen treatments as macromolecules like protein and starch retain more amount of water in the bound state. The results of the changes in T2 showed that water status during grain development was not only affected by developmental processes but also by nitrogen supply to plants. This study strongly indicated a clear nutrient and developmental stage dependence of grain tissue water status in maize. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  15. How Accurately Do Maize Crop Models Simulate the Interactions of Atmospheric CO2 Concentration Levels With Limited Water Supply on Water Use and Yield?

    Science.gov (United States)

    Durand, Jean-Louis; Delusca, Kenel; Boote, Ken; Lizaso, Jon; Manderscheid, Remy; Weigel, Hans Johachim; Ruane, Alexander Clark; Rosenzweig, Cynthia E.; Jones, Jim; Ahuja, Laj; hide

    2017-01-01

    This study assesses the ability of 21 crop models to capture the impact of elevated CO2 concentration [CO2] on maize yield and water use as measured in a 2-year Free Air Carbon dioxide Enrichment experiment conducted at the Thunen Institute in Braunschweig, Germany (Manderscheid et al. 2014). Data for ambient [CO2] and irrigated treatments were provided to the 21 models for calibrating plant traits, including weather, soil and management data as well as yield, grain number, above ground biomass, leaf area index, nitrogen concentration in biomass and grain, water use and soil water content. Models differed in their representation of carbon assimilation and evapotranspiration processes. The models reproduced the absence of yield response to elevated [CO2] under well-watered conditions, as well as the impact of water deficit at ambient [CO2], with 50 percent of models within a range of plus/minus 1 Mg ha(exp. -1) around the mean. The bias of the median of the 21 models was less than 1 Mg ha(exp. -1). However under water deficit in one of the two years, the models captured only 30 percent of the exceptionally high [CO2] enhancement on yield observed. Furthermore the ensemble of models was unable to simulate the very low soil water content at anthesis and the increase of soil water and grain number brought about by the elevated [CO2] under dry conditions. Overall, we found models with explicit stomatal control on transpiration tended to perform better. Our results highlight the need for model improvement with respect to simulating transpirational water use and its impact on water status during the kernel-set phase.

  16. Combined role of heat and water stresses on wheat, maize and rice inter-annual variability and trend from 1980 to 2010.

    Science.gov (United States)

    Zampieri, M.; Ceglar, A., , Dr; Dentener, F., , Dr; van den Berg, M., , Dr; Toreti, A., , Dr

    2017-12-01

    Heat waves and drought are often considered the most damaging climatic stressors for wheat and maize. In this study, based on data derived from observations, we characterize and attribute the effects of these climate extremes on wheat and maize yield anomalies (at global and national scales) with respect to the mean trend from 1980 to 2010. Using a combination of up-to-date heat wave and drought indexes (i.e. the Heat Magnitude Day, HMD, and the Standardized Precipitation Evapotranspiration Index, SPEI), we have developed a composite indicator (i.e. the Combined Stress Index, CSI) that is able to capture the spatio-temporal characteristics of the underlying physical processes in the different agro-climatic regions of the world. At the global level, our diagnostic explains the 42% and the 50% of the inter-annual wheat and maize production variabilities, respectively. The relative importance of heat stress and drought in determining the yield anomalies depends on the region. Compared to maize, and in contrast to common perception, water excess affects wheat production more than drought in several countries. The index definition can be modified in order to quantify the role of combined heat and water stress events occurrence in determining the recorded yield trends as well. Climate change is increasingly limiting maize yields in several countries, especially in Europe and China. A comparable opposite signal, albeit less statistically significant, is found for the USA, which is the main world producer. As for rice, we provide a statistical evidence pointing out to the importance of considering the interactions with the horizontal surface waters fluxes carried out by the rivers. In fact, compared to wheat and maize, the CSI statistical skills in explaining rice production variability are quite reduced. This issue is particularly relevant in paddy fields and flooded lowlands where rice is mainly grown. Therefore, we have modified the procedure including a proxy for the

  17. The effect of newer water-soluble contrast media on I-131 uptake by the thyroid gland

    International Nuclear Information System (INIS)

    Starinsky, R.; Horne, T.; Barr, J.; Ramot, Y.

    2006-01-01

    The aim of this study was to evaluate the effect of two water-soluble contrast media (nonionic and Dimer) on iodine uptake by the thyroid gland. Twenty-eight euthyroid patients (16 females and 12 males) were subjected to 24hrs radioiodine uptake (RAIU) studies following brain CT examinations using the above cited two water-soluble contrast media. Radioiodine uptake studies were done at one (Group-1), two (Group-2) and four (Group-3) weeks following performance of contrast enhanced CT scans. The effect of both contrast media on the thyroid uptake was found to be identical. The radio active iodine uptake (RAIU) was observed to be suppressed in 30% of patients in Group-1, 33% of patients in Group-2 and in none of the patients belonging to Group-3. On the basis of this pilot study on a limited number of patients it was concluded that dimer and non-ionic water soluble contrast media cause suppression of radio iodine uptake by the thyroid gland in a significant proportion of patients. It has also been observed that both contrast media have similar suppressive effects on radio iodine uptake by the thyroid gland. This effect is transient and does not persist beyond a period of four weeks following the administration of the contrast media. (author)

  18. Lead uptake of water plants in water stream at Kiteezi landfill site ...

    African Journals Online (AJOL)

    user

    2Chemistry Laboratory, Uganda Industrial Research Institute, P. O. Box 7086, Kampala, Uganda. Received ... contain heavy metals which compromise water quality .... MATERIALS AND METHODS ... discharged out of the waste water treatment plant pipes. ... with deionized water twice and separated into shoots, stems and.

  19. Uptake of uranium from underground drinking water by chlorella (Chlorella pyrendoidosa)

    International Nuclear Information System (INIS)

    Singhal, R.K.; Joshi, Shobha; Gurg, R.P.; Shenoy, N.S.; Ferandes, Neychelle; Gopale, Rajesh S.; Jhaveri, A.S.

    2002-01-01

    Naturally occurring uranium has found at elevated levels i.e. 300-1200 ppb in underground water, especially in the areas located around uranium mines and granite rocks sites. The U.S. Environmental Protection Agency (EPA) recently adopted drinking water standards requiring a maximum uranium concentration of 20 μgl. This limit is based on nephro-toxicity, rather than on radiological hazards. The concentration of uranium is to be monitored along with other parameters in well and other sources of drinking water in these areas. During this work a low cost kit was developed for removing uranium from under-ground water used for drinking purposes. This unit is capable of reducing uranium from 1000 ppb to 15-20 ppb. Chlorella (Chlorella pyrendoidosa), a fresh water algae, was immobilised in sodium alginate in the form of beads by using 0.2 M calcium chloride. These beads were put in container and the water is stirred occasionally. 99-100 % uranium adsorbed was recovered from the beads by using 0.1 M HNO 3 . These results suggest that the uptake of uranium by Chlorella depended upon the physico-chemical adsorption on the cell surface, but not upon the biological activity and that uranium in the algal cells was coupled with the ligands, which can be easily substituted with NO 3 -1 . (author)

  20. Understanding water uptake in bioaerosols using laboratory measurements, field tests, and modeling

    Science.gov (United States)

    Chaudhry, Zahra; Ratnesar-Shumate, Shanna A.; Buckley, Thomas J.; Kalter, Jeffrey M.; Gilberry, Jerome U.; Eshbaugh, Jonathan P.; Corson, Elizabeth C.; Santarpia, Joshua L.; Carter, Christopher C.

    2013-05-01

    Uptake of water by biological aerosols can impact their physical and chemical characteristics. The water content in a bioaerosol can affect the backscatter cross-section as measured by LIDAR systems. Better understanding of the water content in controlled-release clouds of bioaerosols can aid in the development of improved standoff detection systems. This study includes three methods to improve understanding of how bioaerosols take up water. The laboratory method measures hygroscopic growth of biological material after it is aerosolized and dried. Hygroscopicity curves are created as the humidity is increased in small increments to observe the deliquescence point, then the humidity is decreased to observe the efflorescence point. The field component of the study measures particle size distributions of biological material disseminated into a large humidified chamber. Measurements are made with a Twin-Aerodynamic Particle Sizer (APS, TSI, Inc), -Relative Humidity apparatus where two APS units measure the same aerosol cloud side-by-side. The first operated under dry conditions by sampling downstream of desiccant dryers, the second operated under ambient conditions. Relative humidity was measured within the sampling systems to determine the difference in the aerosol water content between the two sampling trains. The water content of the bioaerosols was calculated from the twin APS units following Khlystov et al. 2005 [1]. Biological material is measured dried and wet and compared to laboratory curves of the same material. Lastly, theoretical curves are constructed from literature values for components of the bioaerosol material.

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

    Science.gov (United States)

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

    2018-04-01

    How much water can be taken up by roots and how this depends on the root and water distributions in the root zone are important questions that need to be answered to describe water fluxes in the soil-plant-atmosphere system. Physically based root water uptake (RWU) models that relate RWU to transpiration, root density, and water potential distributions have been developed but used or tested far less. This study aims at evaluating the simulated RWU of winter wheat using the empirical Feddes-Jarvis (FJ) model and the physically based Couvreur (C) model for different soil water conditions and soil textures compared to sap flow measurements. Soil water content (SWC), water potential, and root development were monitored noninvasively at six soil depths in two rhizotron facilities that were constructed in two soil textures: stony vs. silty, with each of three water treatments: sheltered, rainfed, and irrigated. Soil and root parameters of the two models were derived from inverse modeling and simulated RWU was compared with sap flow measurements for validation. The different soil types and water treatments resulted in different crop biomass, root densities, and root distributions with depth. The two models simulated the lowest RWU in the sheltered plot of the stony soil where RWU was also lower than the potential RWU. In the silty soil, simulated RWU was equal to the potential uptake for all treatments. The variation of simulated RWU among the different plots agreed well with measured sap flow but the C model predicted the ratios of the transpiration fluxes in the two soil types slightly better than the FJ model. The root hydraulic parameters of the C model could be constrained by the field data but not the water stress parameters of the FJ model. This was attributed to differences in root densities between the different soils and treatments which are accounted for by the C model, whereas the FJ model only considers normalized root densities. The impact of differences in

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

    Directory of Open Access Journals (Sweden)

    G. Cai

    2018-04-01

    Full Text Available How much water can be taken up by roots and how this depends on the root and water distributions in the root zone are important questions that need to be answered to describe water fluxes in the soil–plant–atmosphere system. Physically based root water uptake (RWU models that relate RWU to transpiration, root density, and water potential distributions have been developed but used or tested far less. This study aims at evaluating the simulated RWU of winter wheat using the empirical Feddes–Jarvis (FJ model and the physically based Couvreur (C model for different soil water conditions and soil textures compared to sap flow measurements. Soil water content (SWC, water potential, and root development were monitored noninvasively at six soil depths in two rhizotron facilities that were constructed in two soil textures: stony vs. silty, with each of three water treatments: sheltered, rainfed, and irrigated. Soil and root parameters of the two models were derived from inverse modeling and simulated RWU was compared with sap flow measurements for validation. The different soil types and water treatments resulted in different crop biomass, root densities, and root distributions with depth. The two models simulated the lowest RWU in the sheltered plot of the stony soil where RWU was also lower than the potential RWU. In the silty soil, simulated RWU was equal to the potential uptake for all treatments. The variation of simulated RWU among the different plots agreed well with measured sap flow but the C model predicted the ratios of the transpiration fluxes in the two soil types slightly better than the FJ model. The root hydraulic parameters of the C model could be constrained by the field data but not the water stress parameters of the FJ model. This was attributed to differences in root densities between the different soils and treatments which are accounted for by the C model, whereas the FJ model only considers normalized root densities

  3. Root - shoot - signaling in Chenopodium rubrum L. as studied by 15O labeled water uptake

    International Nuclear Information System (INIS)

    Ohya, T.; Hayashi, Y.; Tanoi, K.; Rai, H.; Nakanishi, T.M.; Suzuki, K.; Albrechtova, J.T.P.; Wagner, E.

    2005-01-01

    Full text: It has been demonstrated with C. rubrum that the different organ systems are transmitting surface action potentials which might be the basis for systemic signal transduction. Shoot tip respectively root generated action potentials travel along the stem axis. Shoot tip generated action potentials arriving at the basis can be reflected and travel upwards. The radioactive labeling technique was established at the NIRS in Inage, Japan. About 2 GBq of 15 O labeled Hoagland's solution was supplied to the plant root or cut stem in a phytotron at 25 o C with 45 % of relative humidity and continuous light. By cutting the shoot apical bud and the apices of main side branches the uptake of 15 O labeled water was inhibited in plants with intact roots but not in plants with roots cut. Because of the short half-life of 15 O (2 min), experiments could be repeated in hourly intervals. Cutting the apex probably limits root water uptake via a hydraulic-electrochemical signal. The results are discussed with respect to the significance of a continuous communication between the root system and the shoot apical meristem(s) in the adaptation of plants to their environment. (author)

  4. Aluminum uptake from natural waters by a radiation-grafted membrane

    Energy Technology Data Exchange (ETDEWEB)

    Bazante-Yamaguishi, Renata; Moura, Eduardo; Manzoli, Jose E.; Geraldo, Aurea B.C., E-mail: ageraldo@ipen.br, E-mail: ryamaguishi@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    Styrene grafted, chemically modified polymeric membranes were used to carry off aluminum of drinking water from wells located at Billings dam region. The membranes comprised polymeric substrates of PVC (polyvinylchloride) and PP (polypropylene), which were mutually grafted with gamma radiation. The chemical modification included three basic reaction paths: Friedel-Crafts acylation, 2-methylanisole coupling and a final oxidation; this modification enables aluminum selectivity on the membrane. This chemical process inserts a salicylated derivative bonded onto the aromatic ring of styrene; such molecular arrangement is responsible for complexation of aluminum ions. The aluminum sorption capacity of these membranes was evaluated firstly from an aluminum control solution, where parameters like the ideal pH value for aluminum sorption and the interfering species were studied and correlated to know the best conditions for aluminum uptake. Later, the membranes were used for aluminum remediation of natural waters (real-life samples). The applicability results and limits are then discussed. (author)

  5. Aluminum uptake from natural waters by a radiation-grafted membrane

    International Nuclear Information System (INIS)

    Bazante-Yamaguishi, Renata; Moura, Eduardo; Manzoli, Jose E.; Geraldo, Aurea B.C.

    2013-01-01

    Styrene grafted, chemically modified polymeric membranes were used to carry off aluminum of drinking water from wells located at Billings dam region. The membranes comprised polymeric substrates of PVC (polyvinylchloride) and PP (polypropylene), which were mutually grafted with gamma radiation. The chemical modification included three basic reaction paths: Friedel-Crafts acylation, 2-methylanisole coupling and a final oxidation; this modification enables aluminum selectivity on the membrane. This chemical process inserts a salicylated derivative bonded onto the aromatic ring of styrene; such molecular arrangement is responsible for complexation of aluminum ions. The aluminum sorption capacity of these membranes was evaluated firstly from an aluminum control solution, where parameters like the ideal pH value for aluminum sorption and the interfering species were studied and correlated to know the best conditions for aluminum uptake. Later, the membranes were used for aluminum remediation of natural waters (real-life samples). The applicability results and limits are then discussed. (author)

  6. Leaching due to hygroscopic water uptake in cemented waste containing soluble salts

    DEFF Research Database (Denmark)

    Brodersen, K.

    1992-01-01

    conditions, condensation of water vapour will result in generation of a certain amount of liquid in the form of a strong salt solution. The volume of liquid may well exceed the storage capacity of the pore system in the cemented material and in the release of a limited amount of free contaminated solution......Considerable amounts of easily soluble salts such as sodium nitrate, sulphate, or carbonate are introduced into certain types of cemented waste. When such materials are stored in atmospheres with high relative humidity or disposed or by shallow land burial under unsaturated, but still humid....... A model of the quantitative aspects for the equilibrium situation is presented. Experiments with hygroscopic water uptake support the model and give indications about the rate of the process. The release mechanism is only thought to be important for radionuclides which are not fixed in a low...

  7. Modeling the water use efficiency of soybean and maize plants under environmental stresses: application of a synthetic model of photosynthesis-transpiration based on stomatal behavior.

    Science.gov (United States)

    Yu, Gui-Rui; Wang, Qiu-Feng; Zhuang, Jie

    2004-03-01

    Understanding the variability of plant WUE and its control mechanism can promote the comprehension to the coupling relationship of water and carbon cycle in terrestrial ecosystem, which is the foundation for developing water-carbon coupling cycle model. In this paper, we made clear the differences of net assimilation rate, transpiration rate, and WUE between the two species by comparing the experiment data of soybean (Glycine max Merr.) and maize (Zea mays L.) plants under water and soil nutrient stresses. WUE of maize was about two and a half times more than that of soybean in the same weather conditions. Enhancement of water stresses led to the marked decrease of Am and Em of two species, but water stresses of some degree could improve WUE, and this effect was more obvious for soybean. WUE of the two species changed with psiL in a second-order curve relation, and the WUE at high fertilization was higher than that at low fertilization, this effect was especially obvious for maize. Moreover, according to the synthetic model of photosynthesis-transpiration based on stomatal behavior (SMPTSB) presented by Yu et al. (2001), the WUE model and its applicability were discussed with the data measured in this experiment. The WUE estimated by means of the model accorded well with the measured values. However, this model underestimated the WUE for maize slightly, thus further improvement on the original model was made in this study. Finally, by discussing some physiological factors controlling Am and WUE, we made clear the physiological explanation for differences of the relative contributions of stomata- and mesophyll processes to control of Am and WUE, and the applicability of WUE model between the two species. Because the requirement to stomatal conductance by unit change of net assimilation rate is different, the responses of opening-closing activity of stomata to environmental stresses are different between the two species. To obtain the same level of net assimilation

  8. Quantitative analysis of yield and soil water balance for summer maize on the piedmont of the North China Plain using AquaCrop

    Directory of Open Access Journals (Sweden)

    Jingjing WANG,Feng HUANG,Baoguo LI

    2015-12-01

    Full Text Available The North China Plain (NCP is a major grain production area in China, but the current winter wheat-summer maize system has resulted in a large water deficit. This water-shortage necessitates the improvement of crop water productivity in the NCP. A crop water model, AquaCrop, was adopted to investigate yield and water productivity (WP for rain-fed summer maize on the piedmont of the NCP. The data sets to calibrate and validate the model were obtained from a 3-year (2011—2013 field experiment conducted on the Yanshan piedmont of the NCP. The range of root mean square error (RMSE between the simulated and measured biomass was 0.67—1.25 t·hm-2, and that of relative error (RE was 9.4%—15.4%, the coefficient of determination (R2 ranged from 0.992 to 0.994. The RMSE between the simulated and measured soil water storage at depth of 0—100 cm ranged from 4.09 to 4.39 mm; and RE and R2 in the range of 1.07%—1.20% and 0.880—0.997, respectively. The WP as measured by crop yield per unit evapotranspiration was 2.50—2.66 kg·m-3. The simulated impact of long-term climate (i.e., 1980—2010 and groundwater depth on crop yield and WP revealed that the higher yield and WP could be obtained in dry years in areas with capillary recharge from groundwater, and much lower values elsewhere. The simulation also suggested that supplementary irrigation in areas without capillary groundwater would not result in groundwater over-tapping since the precipitation can meet the water required by both maize and ecosystem, thus a beneficial outcome for both food and ecosystem security can be assured.

  9. Acclimation to high CO2 in maize is related to water status and dependent on leaf rank.

    Science.gov (United States)

    Prins, Anneke; Mukubi, Josephine Muchwesi; Pellny, Till K; Verrier, Paul J; Beyene, Getu; Lopes, Marta Silva; Emami, Kaveh; Treumann, Achim; Lelarge-Trouverie, Caroline; Noctor, Graham; Kunert, Karl J; Kerchev, Pavel; Foyer, Christine H

    2011-02-01

    The responses of C(3) plants to rising atmospheric CO(2) levels are considered to be largely dependent on effects exerted through altered photosynthesis. In contrast, the nature of the responses of C(4) plants to high CO(2) remains controversial because of the absence of CO(2) -dependent effects on photosynthesis. In this study, the effects of atmospheric CO(2) availability on the transcriptome, proteome and metabolome profiles of two ranks of source leaves in maize (Zea mays L.) were studied in plants grown under ambient CO(2) conditions (350 +/- 20 µL L(-1) CO(2) ) or with CO(2) enrichment (700 +/- 20 µL L(-1) CO(2) ). Growth at high CO(2) had no effect on photosynthesis, photorespiration, leaf C/N ratios or anthocyanin contents. However, leaf transpiration rates, carbohydrate metabolism and protein carbonyl accumulation were altered at high CO(2) in a leaf-rank specific manner. Although no significant CO(2) -dependent changes in the leaf transcriptome were observed, qPCR analysis revealed that the abundance of transcripts encoding a Bowman-Birk protease inhibitor and a serpin were changed by the growth CO(2) level in a leaf rank specific manner. Moreover, CO(2) -dependent changes in the leaf proteome were most evident in the oldest source leaves. Small changes in water status may be responsible for the observed responses to high CO(2,) particularly in the older leaf ranks. © 2010 Blackwell Publishing Ltd.

  10. Selenium Supplementation Affects Physiological and Biochemical Processes to Improve Fodder Yield and Quality of Maize (Zea mays L.) under Water Deficit Conditions

    Science.gov (United States)

    Nawaz, Fahim; Naeem, Muhammad; Ashraf, Muhammad Y.; Tahir, Muhammad N.; Zulfiqar, Bilal; Salahuddin, Muhammad; Shabbir, Rana N.; Aslam, Muhammad

    2016-01-01

    Climate change is one of the most complex challenges that pose serious threats to livelihoods of poor people who rely heavily on agriculture and livestock particularly in climate-sensitive developing countries of the world. The negative effects of water scarcity, due to climate change, are not limited to productivity food crops but have far-reaching consequences on livestock feed production systems. Selenium (Se) is considered essential for animal health and has also been reported to counteract various abiotic stresses in plants, however, understanding of Se regulated mechanisms for improving nutritional status of fodder crops remains elusive. We report the effects of exogenous selenium supply on physiological and biochemical processes that may influence green fodder yield and quality of maize (Zea mays L.) under drought stress conditions. The plants were grown in lysimeter tanks under natural conditions and were subjected to normal (100% field capacity) and water stress (60% field capacity) conditions. Foliar spray of Se was carried out before the start of tasseling stage (65 days after sowing) and was repeated after 1 week, whereas, water spray was used as a control. Drought stress markedly reduced the water status, pigments and green fodder yield and resulted in low forage quality in water stressed maize plants. Nevertheless, exogenous Se application at 40 mg L-1 resulted in less negative leaf water potential (41%) and enhanced relative water contents (30%), total chlorophyll (53%), carotenoid contents (60%), accumulation of total free amino acids (40%) and activities of superoxide dismutase (53%), catalase (30%), peroxidase (27%), and ascorbate peroxidase (27%) with respect to control under water deficit conditions. Consequently, Se regulated processes improved fodder yield (15%) and increased crude protein (47%), fiber (10%), nitrogen free extract (10%) and Se content (36%) but did not affect crude ash content in water stressed maize plants. We propose that Se

  11. Selenium Supplementation Affects Physiological and Biochemical Processes to Improve Fodder Yield and Quality of Maize (Zea mays L.) under Water Deficit Conditions.

    Science.gov (United States)

    Nawaz, Fahim; Naeem, Muhammad; Ashraf, Muhammad Y; Tahir, Muhammad N; Zulfiqar, Bilal; Salahuddin, Muhammad; Shabbir, Rana N; Aslam, Muhammad

    2016-01-01

    Climate change is one of the most complex challenges that pose serious threats to livelihoods of poor people who rely heavily on agriculture and livestock particularly in climate-sensitive developing countries of the world. The negative effects of water scarcity, due to climate change, are not limited to productivity food crops but have far-reaching consequences on livestock feed production systems. Selenium (Se) is considered essential for animal health and has also been reported to counteract various abiotic stresses in plants, however, understanding of Se regulated mechanisms for improving nutritional status of fodder crops remains elusive. We report the effects of exogenous selenium supply on physiological and biochemical processes that may influence green fodder yield and quality of maize ( Zea mays L.) under drought stress conditions. The plants were grown in lysimeter tanks under natural conditions and were subjected to normal (100% field capacity) and water stress (60% field capacity) conditions. Foliar spray of Se was carried out before the start of tasseling stage (65 days after sowing) and was repeated after 1 week, whereas, water spray was used as a control. Drought stress markedly reduced the water status, pigments and green fodder yield and resulted in low forage quality in water stressed maize plants. Nevertheless, exogenous Se application at 40 mg L -1 resulted in less negative leaf water potential (41%) and enhanced relative water contents (30%), total chlorophyll (53%), carotenoid contents (60%), accumulation of total free amino acids (40%) and activities of superoxide dismutase (53%), catalase (30%), peroxidase (27%), and ascorbate peroxidase (27%) with respect to control under water deficit conditions. Consequently, Se regulated processes improved fodder yield (15%) and increased crude protein (47%), fiber (10%), nitrogen free extract (10%) and Se content (36%) but did not affect crude ash content in water stressed maize plants. We propose that

  12. Selenium Supplementation Affects Physiological and Biochemical Processes to Improve Fodder Yield and Quality of Maize (Zea mays L. under Water Deficit Conditions

    Directory of Open Access Journals (Sweden)

    Fahim Nawaz

    2016-09-01

    Full Text Available Climate change is one of the most complex challenges that pose serious threats to livelihoods of poor people who rely heavily on agriculture and livestock particularly in climate-sensitive developing countries of the world. The negative effects of water scarcity, due to climate change, are not limited to productivity food crops but have far-reaching consequences on livestock feed production systems. Selenium (Se is considered essential for animal health and has also been reported to counteract various abiotic stresses in plants however, understanding of Se regulated mechanisms for improving nutritional status of fodder crops remains elusive. We report the effects of exogenous selenium (Se supply on physiological and biochemical processes that may influence green fodder yield and quality of maize (Zea mays L. under drought stress conditions. The plants were grown in lysimeter tanks under natural conditions and were subjected to normal (100% field capacity and water stress (60% field capacity conditions. Foliar spray of Se was carried out before the start of tasseling stage (65 days after sowing and was repeated after one week, whereas water spray was used as a control. Drought stress markedly reduced the water status, pigments and green fodder yield and resulted in low forage quality in water stressed maize plants. Nevertheless, exogenous Se application at 40 mg L-1 resulted in less negative leaf water potential (41% and enhanced relative water contents (30%, total chlorophyll (53%, carotenoid contents (60%, accumulation of total free amino acids (40% and activities of superoxide dismutase (53%, catalase (30%, peroxidase (27% and ascorbate peroxidase (27% with respect to control under water deficit conditions. Consequently, Se regulated processes improved fodder yield (15% and increased crude protein (47%, fibre (10%, nitrogen free extract (10% and Se content (36% but did not affect crude ash content in water stressed maize plants. We propose

  13. Enantio-selective molecular dynamics of (±)-o,p-DDT uptake and degradation in water-sediment system.

    Science.gov (United States)

    Ali, Imran; Alharbi, Omar M L; Alothman, Zeid A; Alwarthan, Abdulrahman

    2018-01-01

    Enantio-selective molecular dynamics of (±)-o,p-DDT uptake and degradation in water-sediment system is described. Both uptake and degradation processes of (-)-o,p-DDT were slightly higher than (+)-o,p-DDT enantiomer. The optimized parameters for uptake were 7.0μgL -1 concentration of o,p-DDT, 60min contact time, 5.0pH, 6.0gL -1 amount of reverine sediment and 25°C temperature. The maximum degradation of both (-)- and (+)-o,p-DDT was obtained with 16 days, 0.4μgL -1 concentration of o,p-DDT, pH 7 and 35°C temperature. Both uptake and degraded process followed first order rate reaction. Thermodynamic parameters indicated exothermic nature of uptake and degradation processes. Both uptake and degradation were slightly higher for (-)-enantiomer in comparison to (+)-enantiomer of o,p-DDT. It was concluded that both uptake and degradation processes are responsible for the removal of o,p-DDT from nature but uptake plays a crucial role. The percentage degradations of (-)- and (+)-o,p-DDT were 30.1 and 29.5, respectively. This study may be useful to manage o,p-DDT contamination of our earth's ecosystem. Copyright © 2017. Published by Elsevier Inc.

  14. Extraction and separation of water soluble proteins from Bacillus thuringiensis-transgenic and non-transgenic maize species by CZE

    Czech Academy of Sciences Publication Activity Database

    Sázelová, Petra; Kašička, Václav; Ibanez, E.; Cifuentes, A.

    2009-01-01

    Roč. 32, č. 21 (2009), s. 3801-3808 ISSN 1615-9306 R&D Projects: GA ČR(CZ) GA203/08/1428 Grant - others:GA ČR(CZ) GA203/09/0675 Program:GA Institutional research plan: CEZ:AV0Z40550506 Keywords : Bacillus thuringiensis -transgenic maize * CZE-UV profiling * Maize proteins Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.551, year: 2009

  15. Impacts of water availability and drought on maize yield – A comparison of 16 indicators

    Czech Academy of Sciences Publication Activity Database

    Žalud, Zdeněk; Hlavinka, Petr; Prokeš, K.; Semerádová, Daniela; Balek, Jan; Trnka, Miroslav

    2017-01-01

    Roč. 188, JUL (2017), s. 126-135 ISSN 0378-3774 R&D Projects: GA MŠk(CZ) LO1415; GA MZe QJ1310123; GA MZe(CZ) QJ1610072 Institutional support: RVO:86652079 Keywords : Drought * Hybrids * Precipitation * Soil water holding capacity * Water balance * Water use efficiency Subject RIV: GC - Agronomy OBOR OECD: Agronomy, plant breeding and plant protection Impact factor: 2.848, year: 2016

  16. Soil water balance approach in root zone of maize (95-TZEEY ...

    African Journals Online (AJOL)

    Water balance approach is the simplest method in the study of plant water consumption. The experiment was established in 4.0 x 5.0 m plots in a randomized complete block design containing six (6) treatments water application (3-days, 4-days, 5-days, 6-days, 7-days and 8-days which correspond to T1, T2, T3, T4, T5 and ...

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

    Science.gov (United States)

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

  18. Uptake of Vibrio cholerae biotype eltor from contaminated water by water hyacinth (eichornia crassipes).

    Science.gov (United States)

    Spira, W M; Huq, A; Ahmed, Q S; Saeed, Y A

    1981-09-01

    Vibrio cholerae biotype eltor appears to concentrate on the surface of the water hyacinth (Eichornia crassipes), thereby enhancing its survival and its potential for transmission through waterways of cholera-endemic regions such as Bangladesh.

  19. Uptake of Vibrio cholerae Biotype eltor from Contaminated Water by Water Hyacinth (Eichornia crassipes)

    OpenAIRE

    Spira, William M.; Huq, Anwarul; Ahmed, Qazi Shafi; Saeed, Yusuf A.

    1981-01-01

    Vibrio cholerae biotype eltor appears to concentrate on the surface of the water hyacinth (Eichornia crassipes), thereby enhancing its survival and its potential for transmission through waterways of cholera-endemic regions such as Bangladesh.

  20. Water Uptake Profile In a Model Ion-Exchange Membrane: Conditions For Water-Rich Channels

    Science.gov (United States)

    2014-12-01

    these issues, more research is needed to improve their performance. Aqueous alkaline electrolytes such as potassium hydroxide (KOH) trace their begin...1.2 Water distribution Motivation Hydroxide ion transport through the membrane is fundamentally dependent on the amount and distribution of water...hydrophilic-to-hydrophobic ratio, for several reasons. First, this is the case for Nafion, the gold standard for PEM membranes; its unique pore structure

  1. Viscous organic aerosol particles in the upper troposphere: diffusivity-controlled water uptake and ice nucleation?

    Directory of Open Access Journals (Sweden)

    D. M. Lienhard

    2015-12-01

    secondary organic aerosol (SOA material produced by oxidation of α-pinene and in a number of organic/inorganic model mixtures (3-methylbutane-1,2,3-tricarboxylic acid (3-MBTCA, levoglucosan, levoglucosan/NH4HSO4, raffinose are presented. These indicate that water diffusion coefficients are determined by several properties of the aerosol substance and cannot be inferred from the glass transition temperature or bouncing properties. Our results suggest that water diffusion in SOA particles is faster than often assumed and imposes no significant kinetic limitation on water uptake and release at temperatures above 220 K. The fast diffusion of water suggests that heterogeneous ice nucleation on a glassy core is very unlikely in these systems. At temperatures below 220 K, model simulations of SOA particles suggest that heterogeneous ice nucleation may occur in the immersion mode on glassy cores which remain embedded in a liquid shell when experiencing fast updraft velocities. The particles absorb significant quantities of water during these updrafts which plasticize their outer layers such that these layers equilibrate readily with the gas phase humidity before the homogeneous ice nucleation threshold is reached. Glass formation is thus unlikely to restrict homogeneous ice nucleation. Only under most extreme conditions near the very high tropical tropopause may the homogeneous ice nucleation rate coefficient be reduced as a consequence of slow condensed-phase water diffusion. Since the differences between the behavior limited or non limited by diffusion are small even at the very high tropical tropopause, condensed-phase water diffusivity is unlikely to have significant consequences on the direct climatic effects of SOA particles under tropospheric conditions.

  2. Uptake of water via branches helps timberline conifers refill embolized xylem in late winter.

    Science.gov (United States)

    Mayr, Stefan; Schmid, Peter; Laur, Joan; Rosner, Sabine; Charra-Vaskou, Katline; Dämon, Birgit; Hacke, Uwe G

    2014-04-01

    Xylem embolism is a limiting factor for woody species worldwide. Conifers at the alpine timberline are exposed to drought and freeze-thaw stress during winter, which induce potentially lethal embolism. Previous studies indicated that timberline trees survive by xylem refilling. In this study on Picea abies, refilling was monitored during winter and spring seasons and analyzed in the laboratory and in situ experiments, based on hydraulic, anatomical, and histochemical methods. Refilling started in late winter, when the soil was frozen and soil water not available for the trees. Xylem embolism caused up to 86.2% ± 3.1% loss of conductivity and was correlated with the ratio of closed pits. Refilling of xylem as well as recovery in shoot conductance started in February and corresponded with starch accumulation in secondary phloem and in the mesophyll of needles, where we also observed increasing aquaporin densities in the phloem and endodermis. This indicates that active, cellular processes play a role for refilling even under winter conditions. As demonstrated by our experiments, water for refilling was thereby taken up via the branches, likely by foliar water uptake. Our results suggest that refilling is based on water shifts to embolized tracheids via intact xylem, phloem, and parenchyma, whereby aquaporins reduce resistances along the symplastic pathway and aspirated pits facilitate isolation of refilling tracheids. Refilling must be taken into account as a key process in plant hydraulics and in estimating future effects of climate change on forests and alpine tree ecosystems.

  3. Use of gold nanoparticles to detect water uptake in vascular plants.

    Science.gov (United States)

    Hwang, Bae Geun; Ahn, Sungsook; Lee, Sang Joon

    2014-01-01

    Direct visualization of water-conducting pathways and sap flows in xylem vessels is important for understanding the physiology of vascular plants and their sap ascent. Gold nanoparticles (AuNPs) combined with synchrotron X-ray imaging technique is a new promising tool for investigating plant hydraulics in opaque xylem vessels of vascular plants. However, in practical applications of AuNPs for real-time quantitative visualization of sap flows, their interaction with a vascular network needs to be verified in advance. In this study, the effect of AuNPs on the water-refilling function of xylem vessels is experimentally investigated with three monocot species. Discrepancy in the water uptakes starts to appear at about 20 min to 40 min after the supply of AuNP solution to the test plant by the possible gradual accumulation of AuNPs on the internal structures of vasculature. However conclusively, it is observed that the water-refilling speeds in individual xylem vessels are virtually unaffected by hydrophilically surface-modified AuNPs (diameter ∼20 nm). Therefore, the AuNPs can be effectively used as flow tracers in the xylem vessels in the first 20∼30 min without any physiological barrier. As a result, AuNPs are found to be useful for visualizing various fluid dynamic phenomena occurring in vascular plants.

  4. Foliar uptake of fog water and transport belowground alleviates drought effects in the cloud forest tree species, Drimys brasiliensis (Winteraceae).

    Science.gov (United States)

    Eller, Cleiton B; Lima, Aline L; Oliveira, Rafael S

    2013-07-01

    Foliar water uptake (FWU) is a common water acquisition mechanism for plants inhabiting temperate fog-affected ecosystems, but the prevalence and consequences of this process for the water and carbon balance of tropical cloud forest species are unknown. We performed a series of experiments under field and glasshouse conditions using a combination of methods (sap flow, fluorescent apoplastic tracers and stable isotopes) to trace fog water movement from foliage to belowground components of Drimys brasiliensis. In addition, we measured leaf water potential, leaf gas exchange, leaf water repellency and growth of plants under contrasting soil water availabilities and fog exposure in glasshouse experiments to evaluate FWU effects on the water and carbon balance of D. brasiliensis saplings. Fog water diffused directly through leaf cuticles and contributed up to 42% of total foliar water content. FWU caused reversals in sap flow in stems and roots of up to 26% of daily maximum transpiration. Fog water transported through the xylem reached belowground pools and enhanced leaf water potential, photosynthesis, stomatal conductance and growth relative to plants sheltered from fog. Foliar uptake of fog water is an important water acquisition mechanism that can mitigate the deleterious effects of soil water deficits for D. brasiliensis. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

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

    Science.gov (United States)

    Stanton, Kelly M; Mickelbart, Michael V

    2014-01-01

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

  6. Oscillatory water sorption test for determining water uptake behavior in bread crust

    NARCIS (Netherlands)

    Nieuwenhuijzen, N.H. van; Tromp, R.H.; Hamer, R.J.; Vliet, T. van

    2007-01-01

    In this work, water sorption kinetics of bread crust are described using an oscillatory sorption test in combination with a Langmuir type equation. Both kinetic and thermodynamic information could be obtained at the same time. An advantage of applying a Langmuir type equation for a quantitative

  7. Romanian maize

    DEFF Research Database (Denmark)

    Sauer, Johannes; Balint, Borbala

    This research aims at shedding empirical light on the relative efficiency of small-scale maize producers in Romania. Farmers in transition countries still face heavily distorted price systems resulting from imperfect market conditions and socioeconomic and institutional constraints. To capture...

  8. Modeling of the water uptake process for cowpea seeds (vigna unguiculata l.) under common treatment and microwave treatment

    International Nuclear Information System (INIS)

    Demirhan, E.

    2015-01-01

    The water uptake kinetics of cowpea seeds were carried out at two different water absorption treatments - common treatment and microwave treatment - to evaluate the effects of rehydration temperatures and microwave output powers on rehydration. Water uptake of cowpea seeds during soaking in water was studied at various temperatures of 20 - 45 degree C, and at various microwave output powers of 180 - 900 W. As the rehydration temperature and microwave output power increased, the water uptake of cowpea seeds increased and the rehydration time decreased. The Peleg and Richards Models were capable of predicting water uptake of cowpea seeds undergoing common treatment and microwave treatment, respectively. The effective diffusivity values were evaluated by fitting experimental absorption data to Fick second law of diffusion. The effective diffusivity coefficients for cowpea seeds varied from 7.75*10-11 to 1.99*10-10 m2/s and from 2.23*10-9 to 9.78*10-9 m2/s for common treatment and microwave treatment, respectively. (author)

  9. Tritiated water retention on maize and beans after an acute contamination

    International Nuclear Information System (INIS)

    Nulman, R.; Bravo, G.; Ortiz M, J.R.; Archundia, C.

    1977-01-01

    Although tritium is released in large quantities into environment by nuclear industries and peaceful radioisotope utilization, its behavior is not well known. The International Atomic Energy Agency is sponsoring an international study group to obtain more information about tritiated water (HTO) behavior in different ecological systems. This paper presents the studies made on corn and beans after an acute application of tritiated water during their early stages of growth on an experimental field. Sampling and radiochemical analytical methods of tritium and its behaviour on that plants during their growth cycle are outlined. It is shown that the tritiated water retention plot has at least two components, with effective half lifes of about 10 and 100 days for corn, and 8 and 40 days for beans. (author)

  10. Impact of interspecific interactions on the soil water uptake depth in a young temperate mixed species plantation

    Science.gov (United States)

    Grossiord, Charlotte; Gessler, Arthur; Granier, André; Berger, Sigrid; Bréchet, Claude; Hentschel, Rainer; Hommel, Robert; Scherer-Lorenzen, Michael; Bonal, Damien

    2014-11-01

    Interactions between tree species in forests can be beneficial to ecosystem functions and services related to the carbon and water cycles by improving for example transpiration and productivity. However, little is known on below- and above-ground processes leading to these positive effects. We tested whether stratification in soil water uptake depth occurred between four tree species in a 10-year-old temperate mixed species plantation during a dry summer. We selected dominant and co-dominant trees of European beech, Sessile oak, Douglas fir and Norway spruce in areas with varying species diversity, competition intensity, and where different plant functional types (broadleaf vs. conifer) were present. We applied a deuterium labelling approach that consisted of spraying labelled water to the soil surface to create a strong vertical gradient of the deuterium isotope composition in the soil water. The deuterium isotope composition of both the xylem sap and the soil water was measured before labelling, and then again three days after labelling, to estimate the soil water uptake depth using a simple modelling approach. We also sampled leaves and needles from selected trees to measure their carbon isotope composition (a proxy for water use efficiency) and total nitrogen content. At the end of the summer, we found differences in the soil water uptake depth between plant functional types but not within types: on average, coniferous species extracted water from deeper layers than did broadleaved species. Neither species diversity nor competition intensity had a detectable influence on soil water uptake depth, foliar water use efficiency or foliar nitrogen concentration in the species studied. However, when coexisting with an increasing proportion of conifers, beech extracted water from progressively deeper soil layers. We conclude that complementarity for water uptake could occur in this 10-year-old plantation because of inherent differences among functional groups (conifers

  11. Partitioning between primary and secondary metabolism of carbon allocated to roots in four maize genotypes under water deficit and its effects on productivity

    Directory of Open Access Journals (Sweden)

    Alyne Oliveira Lavinsky

    2015-10-01

    Full Text Available Plants may respond to drought by altering biomass allocation to shoots and roots or by changing the metabolic activities in these organs. To determine how drought changes the partitioning of carbon allocated to growth and secondary metabolism in maize roots and how it affects photosynthesis (A and productivity in maize, we evaluated leaf gas exchange, yield componentes, root morphology, and primary and secondary metabolites including total soluble sugars (TSS, starch (S, phenolics (PHE, and lignin (LIG. Data were collected from pot-grown plants of four maize genotypes: BRS 1010 and 2B710 (sensitive genotypes and DKB390 and BRS1055 (tolerant genotypes under two soil water tensions: field capacity (FC, − 18 kPa and water deficit (WD, − 138 kPa. WD was applied at the pre-flowering stage for 12 days and then the water supply was restored and maintained at optimum levels until the end of the cycle. For genotype BRS 1055 under FC, the greatest A did not result in greater grain biomass (DGB because the accumulated photoassimilates had already filled the cells, and thus the excessive TSS synthesized in leaves was allocated to roots in large amounts. However, the sharp decrease in A caused by WD imposition in this genotype did not affect the influx pressure of leaf TSS, which was due largely to conversion of primary metabolites to PHE compounds to increase the length of fine roots. In leaves of DKB390 under WD, both S and TSS were reduced, whereas PHE were increased to prevent excessive water loss and xylem cavitation. Under WD, both BRS1010 and 2B710 genotypes displayed reduced allocation of biomass to shoots and roots and LIG content in leaves, as well as lower A and DGB values. In BRS1010 this response was coupled to S decrease in leaves and TSS increase in roots, whereas in 2B710 there was a concomitant S increase in roots.

  12. Arsenic uptake and accumulation in rice (Oryza sativa L.) with selenite fertilization and water management.

    Science.gov (United States)

    Wan, Yanan; Camara, Aboubacar Younoussa; Huang, Qingqing; Yu, Yao; Wang, Qi; Li, Huafen

    2018-07-30

    The accumulation of arsenic (As) in rice grain is a potential threat to human health. Our study investigated the possible mediatory role of selenite fertilization on As uptake and accumulation by rice (Oryza sativa L.) under different water management regimes (aerobic or flooded) in a pot experiment. Soil solutions were also extracted during the growing season to monitor As dynamics. Results showed that As contents in the soil solutions, seedlings, and mature rice were higher under flooded than under aerobic water management. Under aerobic conditions, selenite additions slightly increased As concentrations in soil solutions (in the last two samplings), but decreased As levels in rice plants. Relative to the control, 0.5 mg kg -1 selenite decreased rice grain As by 27.5%. Under flooded conditions, however, selenite additions decreased As in soil solutions, while increased As in rice grain. Tendencies also showed that selenite additions decreased the proportion of As in rice shoots both at the seedling stage and maturity, and were more effective in aerobic soil. Our results demonstrate that the effect of selenite fertilizer on As accumulation by rice is related to water management. Copyright © 2018 Elsevier Inc. All rights reserved.

  13. Effect of soil acidification on root growth, nutrient and water uptake

    International Nuclear Information System (INIS)

    Marschner, H.

    1989-01-01

    Soil acidification poses various types of stress to plants, especially Al and H + toxicity in roots and Mg and Ca deficiency in roots and shoots. The importance of the various types of stress varies with plant species, location and time. Average data of the chemical composition of the bulk soil or of the molar Ca/Al or Mg/Al ratios in the soil solution without consideration of the Al species are of limited value for precise conclusions of the actual, or for predictions of the potential risk of soil-acidity-induced inhibition of root growth and of nutritional imbalances. The root-induced changes in the rhizosphere and the consequences for Al toxicity and nutrient acquisition by plants deserve more attention. Further it should be considered that roots are not only required for anchoring higher plants in the soil and for nutrient and water uptake. Roots are also important sites for synthesis of phytohormones, cytokinins and abscisic acid in particular, which are transported into the shoots and act either as signals for the water status at the soil-root interface (ABA) or as compounds required for growth and development. Inhibition in root growth may therefore affect shoot growth by means other than water and nutrient supply. (orig./vhe)

  14. Point processes statistics of stable isotopes: analysing water uptake patterns in a mixed stand of Aleppo pine and Holm oak

    Directory of Open Access Journals (Sweden)

    Carles Comas

    2015-04-01

    Full Text Available Aim of study: Understanding inter- and intra-specific competition for water is crucial in drought-prone environments. However, little is known about the spatial interdependencies for water uptake among individuals in mixed stands. The aim of this work was to compare water uptake patterns during a drought episode in two common Mediterranean tree species, Quercus ilex L. and Pinus halepensis Mill., using the isotope composition of xylem water (δ18O, δ2H as hydrological marker. Area of study: The study was performed in a mixed stand, sampling a total of 33 oaks and 78 pines (plot area= 888 m2. We tested the hypothesis that both species uptake water differentially along the soil profile, thus showing different levels of tree-to-tree interdependency, depending on whether neighbouring trees belong to one species or the other. Material and Methods: We used pair-correlation functions to study intra-specific point-tree configurations and the bivariate pair correlation function to analyse the inter-specific spatial configuration. Moreover, the isotopic composition of xylem water was analysed as a mark point pattern. Main results: Values for Q. ilex (δ18O = –5.3 ± 0.2‰, δ2H = –54.3 ± 0.7‰ were significantly lower than for P. halepensis (δ18O = –1.2 ± 0.2‰, δ2H = –25.1 ± 0.8‰, pointing to a greater contribution of deeper soil layers for water uptake by Q. ilex. Research highlights: Point-process analyses revealed spatial intra-specific dependencies among neighbouring pines, showing neither oak-oak nor oak-pine interactions. This supports niche segregation for water uptake between the two species.

  15. Effect of simultaneously induced environmental stimuli on electrical signalling and gas exchange in maize plants.

    Science.gov (United States)

    Vuralhan-Eckert, Jasmin; Lautner, Silke; Fromm, Jörg

    2018-04-01

    Electrical signalling in response to environmental stimuli is a well-known phenomenon in higher plants. For example, in maize, different stimuli, such as wounding or re-irrigation after drought, incite characteristic electrical signals which have quite particular effects on gas exchange. What is less well understood is how plants (specifically maize) respond when two different environmental stimuli are applied simultaneously. To explore this, a three-stage experiment was designed. In the first stage, drought conditions were simulated by decreasing the soil water content to 30-40 % of field capacity. In these conditions, and in contrast to well-watered plants, the maize exhibited only 60-70% of the original level of stomatal conductance and 50-60 % of the original photosynthesis rate. In the second stage of the experiment the plants were re-irrigated and heat stimulated separately. Re-irrigation led to specific electrical signals followed by a gradual increase of gas exchange. In contrast, after heat stimulation of a leaf an electrical signal was evoked that reduced the net CO 2 -uptake rate as well as stomatal conductance. In the third stage, to elucidate how plants process simultaneous re-irrigation and heat stimulation, the drought-stressed maize plants were re-watered and heat-stimulated at the same time. Results showed a two phase response. In the first phase there was a rapid decrease in both the CO 2 uptake rate and the stomatal conductance, while in the second phase each of these parameters increased gradually. Thus, the results strongly support the view that the responses from both stimuli were combined, indicating that maize plants can process simultaneously applied stimuli. Copyright © 2018 Elsevier GmbH. All rights reserved.

  16. Uptake of arsenic, cadmium, lead and mercury from polluted waters by the water hyacinth Eichornia crassipes

    Energy Technology Data Exchange (ETDEWEB)

    Chigbo, F.E.; Smith, R.W.; Shore, F.L.

    1982-01-01

    The water hyacinth Eichornia crassipes was studied as a pollution monitor for the simultaneous accumulation of arsenic, cadmium, lead and mecury. After cultivation of the plants for 2 days in tanks containing 10 ppm of each of the metals in aqueous solution, the plants were harvested and rinsed with tap water. The leaves and stems were separated and analysed for each of the metals. The ratio of the concentration of arsenic and mercury in the leaves to the concentrations in the stems was found to be 2:1. Cadmium and lead showed a concentration ratio in leaves to stems of about 1:1. The leaf concentration of arsenic was the lowest of the metals of 0.3428 mg g/sup -1/ of dried plant material whilst the leaf concentration of cadmium was highest at 0.5740 mg g/sup -1/ of dried plant material. Control plants were grown in unpolluted water. Plants grown in Bay St. Louis, Mississippi sewage lagoon were also analysed. The mercury concentrations of the leaves of plants grown in the sewage lagoon were significantly different from the control sample which had a concentration of 0.0700 mg g/sup -1/ of dried plant material.

  17. Soil mulching significantly enhances yields and water and nitrogen use efficiencies of maize and wheat

    NARCIS (Netherlands)

    Qin, Wei; Hu, Chunsheng; Oenema, Oene

    2015-01-01

    Global crop yields are limited by water and nutrient availability. Soil mulching (with plastic or straw) reduces evaporation, modifies soil temperature and thereby affects crop yields. Reported effects of mulching are sometimes contradictory, likely due to differences in climatic conditions, soil

  18. Infiltration and planting pits for improved water management and maize yield in semi-arid Zimbabwe

    NARCIS (Netherlands)

    Nyakudya, I.W.; Stroosnijder, L.; Nyagumbo, I.

    2014-01-01

    Realising that rainwater harvesting (RWH) improves crop productivity, smallholder farmers in semi-arid Zimbabwe modified contour ridges traditionally used for rainwater management by digging infiltration pits inside contour ridge channels in order to retain more water in crop fields. However,

  19. quixotic coupling between irrigation system and maize-cowpea

    African Journals Online (AJOL)

    ACSS

    number row-1 and maize grain yield, respectively. The ridge ... Key Words: Furrow irrigation, water use efficiency, Zea mays. RÉSUMÉ ... important in arid and semi-arid regions, with ... as maize) canopy is not able to intercept all the solar radiation during the growth period. ... Intercropping maize and legumes considerably ...

  20. Quantification of root water uptake in soil using X-ray computed tomography and image-based modelling.

    Science.gov (United States)

    Daly, Keith R; Tracy, Saoirse R; Crout, Neil M J; Mairhofer, Stefan; Pridmore, Tony P; Mooney, Sacha J; Roose, Tiina

    2018-01-01

    Spatially averaged models of root-soil interactions are often used to calculate plant water uptake. Using a combination of X-ray computed tomography (CT) and image-based modelling, we tested the accuracy of this spatial averaging by directly calculating plant water uptake for young wheat plants in two soil types. The root system was imaged using X-ray CT at 2, 4, 6, 8 and 12 d after transplanting. The roots were segmented using semi-automated root tracking for speed and reproducibility. The segmented geometries were converted to a mesh suitable for the numerical solution of Richards' equation. Richards' equation was parameterized using existing pore scale studies of soil hydraulic properties in the rhizosphere of wheat plants. Image-based modelling allows the spatial distribution of water around the root to be visualized and the fluxes into the root to be calculated. By comparing the results obtained through image-based modelling to spatially averaged models, the impact of root architecture and geometry in water uptake was quantified. We observed that the spatially averaged models performed well in comparison to the image-based models with <2% difference in uptake. However, the spatial averaging loses important information regarding the spatial distribution of water near the root system. © 2017 John Wiley & Sons Ltd.

  1. H2WHOA - 6 to 8 glasses of water an hour: how water can distinguish physiological from pathological uptake in the GIT on PET/CT scans

    International Nuclear Information System (INIS)

    Crowther, M. D.

    2009-01-01

    Full text:Objectives: To determine the effectiveness of water as a negative contrast agent in PET/CT. To determine the amount and timing of water to be administered in order to evaluate specific regions of the gastro-intestinal tract (GIT). To evaluate whether the use of a 'bolus' of a large amount of water is effective in distinguishing physiological from pathological 18F-FDG uptake in the GIT. Method: Over the past seven months, patients who were scanned and on review had FDG-avidity in the stomach, or had FDG-avidity of an uncertain aetiology further along the GIT, were selected for further scanning. Depending on the site of FDG uptake, patients were either given 1) 2 glasses of water on the bed immediately before scanning or 2) given 6-8 glasses of water in the space of an hour and a delay preceded before scanning over the GIT. Results: To date, 11 patients who have had 13 FDG PET/CT scans have had further water-enhanced delayed imaging. 8(61.5%) scans proved water to be a useful contrast agent. In 11(84.6%) cases, an appropriate amount and timing of water ingested assisted in further evaluating a specific region. In 7(53.9%) cases a large bolus of water allowed the reporting doctor to effectively distinguish between physiological and pathological uptake in the GIT. Conclusions: Patients with gastric/gastro-oesophageal/pancreatic cancers benefit from imaging with water in the stomach or small bowel. Scanning patients with discrete, FDG uptake in the large bowel following a large 'bolus' of water can help to distinguish physiological from pathological FDG uptake.

  2. 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.

  3. Uptake and distribution of bisphenol A and nonylphenol in vegetable crops irrigated with reclaimed water.

    Science.gov (United States)

    Lu, Jian; Wu, Jun; Stoffella, Peter J; Wilson, P Chris

    2015-01-01

    The potential uptake and distribution of bisphenol A (BPA) and nonylphenol (NP) (from reclaimed irrigation water) in edible crops was investigated. BPA and NP were spiked into simulated reclaimed water at environmentally relevant concentrations. Two crops (lettuce, Lactuca sativa and tomato, Lycopersicon esculentum) were grown hydroponically in a greenhouse using the spiked irrigation water under two irrigation exposure scenarios (overhead foliar exposure and subsurface root exposure). BPA concentrations in tomato fruit were 26.6 ± 5.8 (root exposure) and 18.3 ± 3.5 (foliar exposure) μg kg(-1), while concentrations in lettuce leaves were 80.6 ± 23.1 (root exposure) and 128.9 ± 17.4 (foliar exposure) μg kg(-1). NP concentrations in tomato fruit were 46.1 ± 6.6 (root exposure) and 24.6 ± 6.4 (foliar exposure) μg kg(-1), while concentrations in lettuce leaves were 144.1 ± 9.2 (root exposure) and 195.0 ± 16.9 (foliar exposure) μg kg(-1). BPA was relatively mobile in lettuce plants regardless of exposure route. Limited mobility was observed for NP in both crops and BPA in tomatoes. The estimated daily intake of BPA and NP through consumption of vegetables irrigated with reclaimed water ranged from 8.9-62.9 to 11.9-95.1 μg, respectively, depending on the exposure route. Copyright © 2014 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2017-12-01

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

  5. The effect of water uptake gradient in membrane electrode assembly on fuel cell performance

    Energy Technology Data Exchange (ETDEWEB)

    Fujita, H., E-mail: hajime.phy@gmail.co [Research Institute for Science Engineering, Waseda University, 103, R.J.Shillman Hall, 3-14-9, Okubo, Shinjuku, Tokyo 169-0072 (Japan); Shiraki, F.; Oshima, Y.; Tatsumi, T.; Yoshikawa, T.; Sasaki, T. [Research Institute for Science Engineering, Waseda University, 103, R.J.Shillman Hall, 3-14-9, Okubo, Shinjuku, Tokyo 169-0072 (Japan); Oshima, A. [Institute for Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Washio, M. [Research Institute for Science Engineering, Waseda University, 103, R.J.Shillman Hall, 3-14-9, Okubo, Shinjuku, Tokyo 169-0072 (Japan)

    2011-02-15

    Novel proton exchange membranes (PEMs) with functionally gradient ionic sites were fabricated utilizing low energy electron beam (EB) irradiations. The low energy electron beam irradiation to polymer membranes possessed the property of gradient energy deposition in the membrane thickness direction. In the process of EB grafting of styrene onto base films, selective ranges of the gradient energy deposition were used. Micro FT-IR spectra showed that the simulated energy deposition of EB irradiation to base polymer membranes in the thickness direction corresponded to the amount of styrene grafted onto EB-irradiated films. After sulfonation, a functionally gradient ionic site PEM (gradient-PEM) was prepared, corresponding to EB depth-dose profile. The functionally gradients of ionic sites in the gradient-PEM and flat-PEM were evaluated with XPS and SEM-EDX. The results of XPS and SEM-EDX suggest that the prepared gradient-PEM had a gradient sulfonated acid groups. In addition, the polarization performance of MEA based on gradient-PEM was improved in high current density. It was thought that water uptake gradient could have a function to prevent flooding in the MEA during FC operation. Thus, the functionally gradient-PEMs could be a promising solution to manage the water behavior in MEA.

  6. The uptake of uranium and radium from food and water in relation to calcium

    International Nuclear Information System (INIS)

    Wrenn, M.E.

    1988-01-01

    Observed ratios for dietary radium and calcium suggest that at least a 20 to 70 fold discrimination exists against radium uptake in the skeleton relative to calcium. It has been widely shown in many countries around the world that the relative radium to calcium ratio in the human skeleton varies from country to country, but within geographic areas, it appears to be relatively invariant with age. The ratio of radium-226 to calcium in intake, relative to the radium-226 to calcium value in the skeleton, is called the observed ratio, and varies over the world from a value of 0.013 to 0.039, with a mean of 0.024. In 1975, I inferred a mean observed ratio for uranium of 0.057 for the US. These findings suggest that man is in equilibrium with radium-226 with respect to the calcium in food and water. Most of the calcium would be ingested in diet, as would a significant amount, but not necessarily all, of the radium. The role of calcium for intake in water has not been examined

  7. The Influence of Water and Solvent Uptake on Functional Properties of Shape-Memory Polymers

    Directory of Open Access Journals (Sweden)

    Ehsan Ghobadi

    2018-01-01

    Full Text Available In this contribution, diffusion of water, acetone, and ethanol into a polymer matrix has been studied experimentally and numerically by finite element approaches. Moreover, the present study reports an assessment of different thermomechanical conditions of the shape-memory (SM performance, for example, stress- or strain-holding times in stress- or strain-controlled thermomechanical cycles and the effect of maximum strain. According to the results presented here, the uptake of acetone in Estane is much higher than ethanol and follows classical Fickian diffusion. Further, a series of thermomechanical measurements conducted on dry and physically (hydrolytically aged polyether urethanes revealed that incorporation of water seems to have an appreciable impact on the shape recovery ratios which can be attributed to the additional physical crosslinks. However, no obvious difference in shape fixation of dry and physically (hydrolytically aged samples could be recognized. Furthermore, by decreasing the strain-holding time, shape recovery improves significantly. Moreover, the shape fixity is found to be independent of holding time. The shape recovery ratio decreased dramatically with an increase in the stress-holding time.

  8. Μetal Uptake by Sunflower (Helianthus annuus) Irrigated with Water Polluted with Chromium and Nickel.

    Science.gov (United States)

    Stoikou, Vasiliki; Andrianos, Vangelis; Stasinos, Sotiris; Kostakis, Marios G; Attiti, Sofia; Thomaidis, Nikolaos S; Zabetakis, Ioannis

    2017-07-17

    The water aquifers of the regions of Asopos River in Viotia and Messapia in Evia (Greece) have been contaminated with hexavalent chromium (Cr (VI)) and bivalent nickel (Ni (II)). Given that these areas are the two biggest tuber producing regions of Greece, in our previous work, the cross-contamination of the food chain with these two heavy metals was quantified. In the present study, the potential of sunflower ( Helianthus annuus ) cultivation in these regions is evaluated. The scope of our study was to investigate the uptake of chromium and nickel by sunflower, in a greenhouse experiment. The study included two cultivation periods of plants in six irrigation lines with different levels of Cr (VI) and Ni (II) ranging from 0 μg/L (control) to 10,000 μg/L. In all plant parts, statistically significant increased levels of Cr (VI) and Ni (II) were found when compared to control ones. Also, a positive correlation, both for Cr and Ni, between levels of heavy metals in irrigation water and plants was observed. Following European Food Safety Authority recommendations, the obtained oil was evaluated as safe for consumption, therefore, sunflower cultivation could be a valid bioremediation solution for the Asopos and Messapia regions.

  9. Radioiodine uptake by plants from soils

    International Nuclear Information System (INIS)

    Sabova, T.

    1976-01-01

    The uptake and accumulation of radioiodine by wheat, maize and peas from various types of soil have been studied. The uptake depends on the type of soil, on its content of organic matter and on the amount of fertilizer. Radioiodine is mainly accumulated in the roots. Accumulation in above-ground plant parts decreases in the following order: wheat, maize, peas. Uptake was highest from humus and clay soils and lowest from black and meadow soils. Application of chloride fertilizer or carrier iodine lead to an increase of radioiodine uptake in the whole plant. (author)

  10. Seasonal plant water uptake patterns in the saline southeast Everglades ecotone.

    Science.gov (United States)

    Ewe, Sharon M L; Sternberg, Leonel da S L; Childers, Daniel L

    2007-07-01

    The purpose of this study was to determine the seasonal water use patterns of dominant macrophytes coexisting in the coastal Everglades ecotone. We measured the stable isotope signatures in plant xylem water of Rhizophora mangle, Cladium jamaicense, and Sesuvium portulacastrum during the dry (DS) and wet (WS) seasons in the estuarine ecotone along Taylor River in Everglades National Park, FL, USA. Shallow soilwater and deeper groundwater salinity was also measured to extrapolate the salinity encountered by plants at their rooting zone. Average soil water oxygen isotope ratios (delta(18)O) was enriched (4.8 +/- 0.2 per thousand) in the DS relative to the WS (0.0 +/- 0.1 per thousand), but groundwater delta(18)O remained constant between seasons (DS: 2.2 +/- 0.4 per thousand; WS: 2.1 +/- 0.1 per thousand). There was an inversion in interstitial salinity patterns across the soil profile between seasons. In the DS, shallow water was euhaline [i.e., 43 practical salinity units (PSU)] while groundwater was less saline (18 PSU). In the WS, however, shallow water was fresh (i.e., 0 PSU) but groundwater remained brackish (14 PSU). All plants utilized 100% (shallow) freshwater during the WS, but in the DS R. mangle switched to a soil-groundwater mix (delta 55% groundwater) while C. jamaicense and S. portulacastrum continued to use euhaline shallow water. In the DS, based on delta(18)O data, the roots of R. mangle roots were exposed to salinities of 25.4 +/- 1.4 PSU, less saline than either C. jamaicense (39.1 +/- 2.2 PSU) or S. portulacastrum (38.6 +/- 2.5 PSU). Although the salinity tolerance of C. jamaicense is not known, it is unlikely that long-term exposure to high salinity is conducive to the persistence of this freshwater marsh sedge. This study increases our ecological understanding of how water uptake patterns of individual plants can contribute to ecosystem levels changes, not only in the southeast saline Everglades, but also in estuaries in general in response to

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

    Science.gov (United States)

    King, G.

    2017-12-01

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

  12. Rates of Water Loss and Uptake in Recalcitrant Fruits of Quercus Species Are Determined by Pericarp Anatomy

    Science.gov (United States)

    Xia, Ke; Daws, Matthew I.; Stuppy, Wolfgang; Zhou, Zhe-Kun; Pritchard, Hugh W.

    2012-01-01

    Desiccation-sensitive recalcitrant seeds and fruits are killed by the loss of even moderate quantities of water. Consequently, minimizing the rate of water loss may be an important ecological factor and evolutionary driver by reducing the risk of mortality during post-dispersal dry-spells. For recalcitrant fruits of a range of Quercus species, prolonged drying times have been observed previously. However, the underlying mechanism(s) for this variation is unknown. Using nine Quercus species we investigated the major route(s) of water flow into and out of the fruits and analysed the relative importance of the different pericarp components and their anatomy on water uptake/loss. During imbibition (rehydration), the surface area of the cupule scar and the frequency and area of the vascular bundles contained therein were significantly correlated with the rates of water uptake across the scar. The vascular bundles serving the apex of the fruit were a minor contributor to overall water. Further, the rate of water uptake across the remainder of the pericarp surface was significantly correlated with the thickness of the vascularised inner layer in the pericarp. Fruits of Q. franchetii and Q. schottkyana dried most slowly and had a comparatively small scar surface area with few vascular bundles per unit area. These species inhabit drier regions than the other species studied, suggesting these anatomical features may have ecological value by reducing the risk of desiccation stress. However, this remains to be tested in the field. PMID:23071795

  13. Acclimation of biochemical and diffusive components of photosynthesis in rice, wheat and maize to heat and water deficit: implications for modeling photosynthesis

    Directory of Open Access Journals (Sweden)

    Juan Alejandro Perdomo

    2016-11-01

    Full Text Available The impact of the combined effects of heat stress, increased vapor pressure deficit (VPD and water deficit on the physiology of major crops needs to be better understood to help identifying the expected negative consequences of climate change and heat waves on global agricultural productivity. To address this issue, rice, wheat and maize plants were grown under control temperature (CT, 25°C, VPD 1.8 kPa, and a high temperature (HT, 38°C, VPD 3.5 kPa, both under well-watered (WW and water deficit (WD conditions. Gas-exchange measurements showed that, in general, WD conditions affected the leaf conductance to CO2, while growth at HT had a more marked effect on the biochemistry of photosynthesis. When combined, HT and WD had an additive effect in limiting photosynthesis. The negative impacts of the imposed treatments on the processes governing leaf gas-exchange were species-dependent. Wheat presented a higher sensitivity while rice and maize showed a higher acclimation potential to increased temperature. Rubisco and PEPC kinetic constants determined in vitro at 25°C and 38°C were used to estimate Vcmax, Jmax and Vpmax in the modeling of C3 and C4 photosynthesis. The results here obtained reiterate the need to use species-specific and temperature-specific values for Rubisco and PEPC kinetic constants for a precise parameterization of the photosynthetic response to changing environmental conditions in different crop species.

  14. Maize yield response to nitrogen as influenced by spatio-temporal variations of soil-water-topography dynamics

    Science.gov (United States)

    Reducing N loss from agricultural lands and applying N fertilizer at rates that satisfy both economic and environmental objectives is critical for sustainable agricultural management. This study investigated spatial variability in maize yield response to N and its controlling factors along a typical...

  15. Differential Responses of Water Uptake Pathways and Expression of Two Aquaporin Genes to Water-Deficit in Rice Seedlings of Two Genotypes

    Directory of Open Access Journals (Sweden)

    Xu Ai-hua

    2017-07-01

    Full Text Available Water-deficit (WD is a major abiotic stress constraining crop productivity worldwide. Zhenshan 97 is a drought-susceptible rice genotype, while IRAT109 is a drought-resistant one. However, the physiological basis of the difference remains unclear. These two genotypes had similar total water uptake rates under both WD and well-watered (WW conditions, and their water uptake rates under WD were significantly decreased compared with those under WW. However, the water uptake rate via the cell-to-cell pathway was significantly increased in Zhenshan 97 but decreased in IRAT109 under WD, whereas the opposite trends were observed through the apoplastic pathway. These results indicated that the stress responses and relative contributions of these two water uptake pathways were associated with rice genotype under WD. The expression levels of OsPIP2;4 and OsPIP2;5 genes were significantly higher in roots of Zhenshan 97 than in IRAT109 under the two conditions. OsPIP2;4 expression in roots was significantly up-regulated under WD, while OsPIP2;5 expression showed no significant change. These results suggest that the expression levels of OsPIP2;4 and OsPIP2;5 in rice are dependent on genotype and water availability. Compared with Zhenshan 97, IRAT109 had a higher root dry weight, water uptake rate and xylem sap flow rate, and lower leaf water potential and root porosity under WD, which might be responsible for the drought resistance in IRAT109.

  16. An improved approach for remotely sensing water stress impacts on forest C uptake.

    Science.gov (United States)

    Sims, Daniel A; Brzostek, Edward R; Rahman, Abdullah F; Dragoni, Danilo; Phillips, Richard P

    2014-09-01

    Given that forests represent the primary terrestrial sink for atmospheric CO2 , projections of future carbon (C) storage hinge on forest responses to climate variation. Models of gross primary production (GPP) responses to water stress are commonly based on remotely sensed changes in canopy 'greenness' (e.g., normalized difference vegetation index; NDVI). However, many forests have low spectral sensitivity to water stress (SSWS) - defined here as drought-induced decline in GPP without a change in greenness. Current satellite-derived estimates of GPP use a vapor pressure deficit (VPD) scalar to account for the low SWSS of forests, but fail to capture their responses to water stress. Our objectives were to characterize differences in SSWS among forested and nonforested ecosystems, and to develop an improved framework for predicting the impacts of water stress on GPP in forests with low SSWS. First, we paired two independent drought indices with NDVI data for the conterminous US from 2000 to 2011, and examined the relationship between water stress and NDVI. We found that forests had lower SSWS than nonforests regardless of drought index or duration. We then compared satellite-derived estimates of GPP with eddy-covariance observations of GPP in two deciduous broadleaf forests with low SSWS: the Missouri Ozark (MO) and Morgan Monroe State Forest (MMSF) AmeriFlux sites. Model estimates of GPP that used VPD scalars were poorly correlated with observations of GPP at MO (r(2) = 0.09) and MMSF (r(2) = 0.38). When we included the NDVI responses to water stress of adjacent ecosystems with high SSWS into a model based solely on temperature and greenness, we substantially improved predictions of GPP at MO (r(2) = 0.83) and for a severe drought year at the MMSF (r(2) = 0.82). Collectively, our results suggest that large-scale estimates of GPP that capture variation in SSWS among ecosystems could improve predictions of C uptake by forests under drought. © 2014 John Wiley & Sons

  17. Identification of QTLs for root characteristics in maize grown in hydroponics and analysis of their overlap with QTLs for grain yield in the field at two water regimes.

    Science.gov (United States)

    Tuberosa, Roberto; Sanguineti, Maria Corinna; Landi, Pierangelo; Giuliani, Marcella Michela; Salvi, Silvio; Conti, Sergio

    2002-01-01

    We investigated the overlap among quantitative trait loci (QTLs) in maize for seminal root traits measured in hydroponics with QTLs for grain yield under well-watered (GY-WW) and water-stressed (GY-WS) field conditions as well as for a drought tolerance index (DTI) computed as GY-WS/GY-WW. In hydroponics, 11, 7, 9, and 10 QTLs were identified for primary root length (R1L), primary root diameter (R1D), primary root weight (R1W), and for the weight of the adventitious seminal roots (R2W), respectively. In the field, 7, 8, and 9 QTLs were identified for GY-WW, GY-WS, and DTI, respectively. Despite the weak correlation of root traits in hydroponics with GY-WW, GY-WS, and DTI, a noticeable overlap between the corresponding QTLs was observed. QTLs for R2W most frequently and consistently overlapped with QTLs for GY-WW, GY-WS, and/or DTI. At four QTL regions, an increase in R2W was positively associated with GY-WW, GY-WS, and/or DTI. A 10 cM interval on chromosome 1 between PGAMCTA205 and php20644 showed the strongest effect on R1L, R1D, R2W, GY-WW, GY-WS, and DTI. These results indicate the feasibility of using hydroponics in maize to identify QTL regions controlling root traits at an early growth stage and also influencing GY in the field. A comparative analysis of the QTL regions herein identified with those described in previous studies investigating root traits in different maize populations revealed a number of QTLs in common.

  18. Application of remote sensing techniques to study aerosol water vapour uptake in a real atmosphere

    Science.gov (United States)

    Fernández, A. J.; Molero, F.; Becerril-Valle, M.; Coz, E.; Salvador, P.; Artíñano, B.; Pujadas, M.

    2018-04-01

    In this work, a study of several observations of aerosol water uptake in a real (non-controlled) atmosphere, registered by remote sensing techniques, are presented. In particular, three events were identified within the Atmospheric Boundary Layer (ABL) and other two events were detected in the free troposphere (beyond the top of the ABL). Then, aerosol optical properties were measured at different relative humidity (RH) conditions by means of a multi-wavelength (MW) Raman lidar located at CIEMAT (Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, Research Centre for Energy, Environment and Technology) facilities in Madrid (Spain). Additionally, aerosol optical and microphysical properties provided by automatic sun and sky scanning spectral radiometers (CIMEL CE-318) and a meteorological analysis complement the study. However, a detailed analysis only could be carried out for the cases observed within the ABL since well-mixed atmospheric layers are required to properly characterize these processes. This characterization of aerosol water uptake is based on the curve described by the backscatter coefficient at 532 nm as a function of RH which allows deriving the enhancement factor. Thus, the Hänel parameterization is utilized, and the results obtained are in the range of values reported in previous studies, which shows the suitability of this approach to study such hygroscopic processes. Furthermore, the anti-correlated pattern observed on backscatter-related Ångström exponent (532/355 nm) and RH indicates plausible signs of aerosol hygroscopic growth. According to the meteorological analysis performed, we attribute such hygroscopic behaviour to marine aerosols which are advected from the Atlantic Ocean to the low troposphere in Madrid. We have also observed an interesting response of aerosols to RH at certain levels which it is suggested to be due to a hysteresis process. The events registered in the free troposphere, which deal with volcano

  19. Computed Tomography-Based Imaging of Voxel-Wise Lesion Water Uptake in Ischemic Brain: Relationship Between Density and Direct Volumetry.

    Science.gov (United States)

    Broocks, Gabriel; Flottmann, Fabian; Ernst, Marielle; Faizy, Tobias Djamsched; Minnerup, Jens; Siemonsen, Susanne; Fiehler, Jens; Kemmling, Andre

    2018-04-01

    Net water uptake per volume of brain tissue may be calculated by computed tomography (CT) density, and this imaging biomarker has recently been investigated as a predictor of lesion age in acute stroke. However, the hypothesis that measurements of CT density may be used to quantify net water uptake per volume of infarct lesion has not been validated by direct volumetric measurements so far. The purpose of this study was to (1) develop a theoretical relationship between CT density reduction and net water uptake per volume of ischemic lesions and (2) confirm this relationship by quantitative in vitro and in vivo CT image analysis using direct volumetric measurements. We developed a theoretical rationale for a linear relationship between net water uptake per volume of ischemic lesions and CT attenuation. The derived relationship between water uptake and CT density was tested in vitro in a set of increasingly diluted iodine solutions with successive CT measurements. Furthermore, the consistency of this relationship was evaluated using human in vivo CT images in a retrospective multicentric cohort. In 50 edematous infarct lesions, net water uptake was determined by direct measurement of the volumetric difference between the ischemic and normal hemisphere and was correlated with net water uptake calculated by ischemic density measurements. With regard to in vitro data, water uptake by density measurement was equivalent to direct volumetric measurement (r = 0.99, P volumetry was 44.7 ± 26.8 mL and the mean percent water uptake per lesion volume was 22.7% ± 7.4%. This was equivalent to percent water uptake obtained from density measurements: 21.4% ± 6.4%. The mean difference between percent water uptake by direct volumetry and percent water uptake by CT density was -1.79% ± 3.40%, which was not significantly different from 0 (P < 0.0001). Volume of water uptake in infarct lesions can be calculated quantitatively by relative CT density measurements. Voxel-wise imaging

  20. Genotypic variation in growth and physiological response to drought stress and re-watering reveals the critical role of recovery in drought adaptation in maize seedlings

    Directory of Open Access Journals (Sweden)

    Daoqian eChen

    2016-01-01

    Full Text Available Non-irrigated crops in temperate climates and irrigated crops in arid climates are subjected to continuous cycles of water stress and re-watering. Thus, fast and efficient recovery from water stress may be among the key determinants of plant drought adaptation. The present study was designed to comparatively analyze the roles of drought resistance and drought recovery in drought adaptation and to investigate the physiological basis of genotypic variation in drought adaptation in maize (Zea mays seedlings. As the seedlings behavior in growth associate with yield under drought, it could partly reflect the potential of drought adaptability. Growth and physiological responses to progressive drought stress and recovery were observed in seedlings of ten maize lines. The results showed that drought adaptability is closely related to drought recovery (r = 0.714**, but not to drought resistance (r = 0.332. Drought induced decreases in leaf water content, water potential, osmotic potential, gas exchange parameters, chlorophyll content, Fv/Fm and nitrogen content, and increased H2O2 accumulation and lipid peroxidation. After recovery, most of these physiological parameters rapidly returned to normal levels. The physiological responses varied between lines. Further correlation analysis indicated that the physiological bases of drought resistance and drought recovery are definitely different, and that maintaining higher chlorophyll content (r = 0.874*** and Fv/Fm (r = 0.626* under drought stress contributes to drought recovery. Our results suggest that both drought resistance and recovery are key determinants of plant drought adaptation, and that drought recovery may play a more important role than previously thought. In addition, leaf water potential, chlorophyll content and Fv/Fm could be used as efficient reference indicators in the selection of drought-adaptive genotypes.

  1. Corrosion and deuterium uptake of Zr-based alloys in supercritical water

    International Nuclear Information System (INIS)

    Khatamian, D.

    2010-01-01

    To increase the thermodynamic efficiency above 40% in nuclear power plants, the use of supercritical water as the heat transport fluid has been suggested. Zircaloy-2, -4, Zr-Cr-Fe, Zr-1Nb and Zr-2.5Nb were tested as prospective fuel cladding materials in 30 MPa D 2 O at 500 o C. Zircaloy-2 showed the highest rates of corrosion and hydriding. Although Zr-Cr-Fe initially showed a very low corrosion rate, it displayed breakaway corrosion kinetics after 50 h exposure. The best-behaved material both from a corrosion and hydrogen uptake point of view was Zr-2.5Nb. However, the Zr-2.5Nb oxide growth rate was still excessive and beyond the current CANDU design allowance. Similar coupons, coated with Cr, were also tested. The coated layer effectively prevented oxidation of the coupons except on the edges, where the coating was thinner and had some flaws. In addition, the Cr-coated Zr-2.5Nb coupons had the lowest deuterium pickup of all the alloys tested and showed no signs of accelerated or nonuniform corrosion. (author)

  2. Radioactivity in Norwegian Waters: Distribution in seawater and sediments, and uptake in marine organisms

    International Nuclear Information System (INIS)

    Heldal, Hilde Elise

    2001-01-01

    Prior to the detonation of the first thermonuclear bomb, small amounts of radioactivity, for example in mineral water, were considered to be health enriching. Negative experiences related to thermonuclear bombs and several nuclear accidents have, however, changed people's attitude towards radioactivity during the past 40-50 years. Today, there is a common concern for regular and potential accidental releases of radioactivity from sources such as Sellafield. Although this is important, incorrect assessments of the effects of these releases (e.g. created by uncritical journalism) have the potential to harm the country's fisheries and economy. Therefore, it is of major importance to document up-to-date levels of radioactive contamination of the marine environment, and be able to place these into the proper perspectives. The main topics of the thesis may be summarised as follows: (1) Distribution of Caesium-137, Plutonium-238, Plutonium-239,240 and Americium-241 in sediments with emphasis on the Spitsbergen-Bear Island area, (2) Uptake of Caesium-137 in phytoplankton representative for the Barents and Norwegian Seas phytoplankton communities (laboratory experiments), (3) Bioaccumulation of Caesium-137 in food webs in the Barents and Norwegian Seas, (4) Geographical variations of Caesium-137 in harbour porpoises (Phocoena phocoena) along the Norwegian coast, (5) Transport times for Technetium-99 from Sellafield to various locations along the Norwegian coast and the Arctic Ocean

  3. Radioactivity in Norwegian Waters: Distribution in seawater and sediments, and uptake in marine organisms

    Energy Technology Data Exchange (ETDEWEB)

    Heldal, Hilde Elise

    2001-07-01

    Prior to the detonation of the first thermonuclear bomb, small amounts of radioactivity, for example in mineral water, were considered to be health enriching. Negative experiences related to thermonuclear bombs and several nuclear accidents have, however, changed people's attitude towards radioactivity during the past 40-50 years. Today, there is a common concern for regular and potential accidental releases of radioactivity from sources such as Sellafield. Although this is important, incorrect assessments of the effects of these releases (e.g. created by uncritical journalism) have the potential to harm the country's fisheries and economy. Therefore, it is of major importance to document up-to-date levels of radioactive contamination of the marine environment, and be able to place these into the proper perspectives. The main topics of the thesis may be summarised as follows: (1) Distribution of Caesium-137, Plutonium-238, Plutonium-239,240 and Americium-241 in sediments with emphasis on the Spitsbergen-Bear Island area, (2) Uptake of Caesium-137 in phytoplankton representative for the Barents and Norwegian Seas phytoplankton communities (laboratory experiments), (3) Bioaccumulation of Caesium-137 in food webs in the Barents and Norwegian Seas, (4) Geographical variations of Caesium-137 in harbour porpoises (Phocoena phocoena) along the Norwegian coast, (5) Transport times for Technetium-99 from Sellafield to various locations along the Norwegian coast and the Arctic Ocean.

  4. Radioactivity in Norwegian Waters: Distribution in seawater and sediments, and uptake in marine organisms

    Energy Technology Data Exchange (ETDEWEB)

    Heldal, Hilde Elise

    2001-07-01

    Prior to the detonation of the first thermonuclear bomb, small amounts of radioactivity, for example in mineral water, were considered to be health enriching. Negative experiences related to thermonuclear bombs and several nuclear accidents have, however, changed people's attitude towards radioactivity during the past 40-50 years. Today, there is a common concern for regular and potential accidental releases of radioactivity from sources such as Sellafield. Although this is important, incorrect assessments of the effects of these releases (e.g. created by uncritical journalism) have the potential to harm the country's fisheries and economy. Therefore, it is of major importance to document up-to-date levels of radioactive contamination of the marine environment, and be able to place these into the proper perspectives. The main topics of the thesis may be summarised as follows: (1) Distribution of Caesium-137, Plutonium-238, Plutonium-239,240 and Americium-241 in sediments with emphasis on the Spitsbergen-Bear Island area, (2) Uptake of Caesium-137 in phytoplankton representative for the Barents and Norwegian Seas phytoplankton communities (laboratory experiments), (3) Bioaccumulation of Caesium-137 in food webs in the Barents and Norwegian Seas, (4) Geographical variations of Caesium-137 in harbour porpoises (Phocoena phocoena) along the Norwegian coast, (5) Transport times for Technetium-99 from Sellafield to various locations along the Norwegian coast and the Arctic Ocean.

  5. A high-flow humidograph for testing the water uptake by ambient aerosol

    Energy Technology Data Exchange (ETDEWEB)

    Ten Brink, H.M.; Khlystov, A.; Kos, G.P.A. [ECN Fuels Conversion and Environment, Petten (Netherlands); Tuch, T. [Institut of Medical Data Management, Biometrics and Epidemiology, Ludwig-Maximilian University, Muenich (Germany); Roth, C.; Kreyling, W. [Institute for Inhalation Biology, GSF National Research Center for Environment and Health, Neuherberg/Muenich (Germany)

    1999-10-01

    A scanning humidograph, with an air flow rate of 0.5 m{sup 3} s{sup -1} was built to investigate the uptake of water and its effect on sizing, collection and light-scattering of ambient aerosol. The performance of the system was assessed with laboratory particles of ammonium nitrate, ammonium sulfate and sodium chloride which are the major hygroscopic components of ambient aerosol. The increase in size at the deliquescence points, which ideally is a stepwise function of relative humidity, occurs over a range of 3% RH units. This is shown to be an optimum value in a system of such large dimensions. Because of the strong temperature increase of the vapor pressure of ammonium nitrate, its evaporative loss was investigated as a function of heating/drying temperature. The loss of pure test aerosol, with a mass distribution similar to that in the ambient atmosphere, was found to be acceptable for drying temperatures of up to 40C. The sizing of deliquesced aerosol by LAS-X monitors was tested and found to be a complex function of RH. In Berner low pressure impactors growth of hygroscopic aerosol was not observed, not even at an RH approaching saturation. 21 refs.

  6. Nanofiber Ion-Exchange Membranes for the Rapid Uptake and Recovery of Heavy Metals from Water

    Directory of Open Access Journals (Sweden)

    Nithinart Chitpong

    2016-12-01

    Full Text Available An evaluation of the performance of polyelectrolyte-modified nanofiber membranes was undertaken to determine their efficacy in the rapid uptake and recovery of heavy metals from impaired waters. The membranes were prepared by grafting poly(acrylic acid (PAA and poly(itaconic acid (PIA to cellulose nanofiber mats. Performance measurements quantified the dynamic ion-exchange capacity for cadmium (Cd, productivity, and recovery of Cd(II from the membranes by regeneration. The dynamic binding capacities of Cd(II on both types of nanofiber membrane were independent of the linear flow velocity, with a residence time of as low as 2 s. Analysis of breakthrough curves indicated that the mass flow rate increased rapidly at constant applied pressure after membranes approached equilibrium load capacity for Cd(II, apparently due to a collapse of the polymer chains on the membrane surface, leading to an increased porosity. This mechanism is supported by hydrodynamic radius (Rh measurements for PAA and PIA obtained from dynamic light scattering, which show that Rh values decrease upon Cd(II binding. Volumetric productivity was high for the nanofiber membranes, and reached 0.55 mg Cd/g/min. The use of ethylenediaminetetraacetic acid as regeneration reagent was effective in fully recovering Cd(II from the membranes. Ion-exchange capacities were constant over five cycles of binding-regeneration.

  7. Measurement of gas/water uptake coefficients for trace gases active in the marine environment

    Energy Technology Data Exchange (ETDEWEB)

    Davidovits, P. (Boston Coll., Chestnut Hill, MA (United States). Dept. of Chemistry); Worsnop, D.W.; Zahniser, M.S.; Kolb, C.E. (Aerodyne Research, Inc., Billerica, MA (United States). Center for Chemical and Environmental Physics)

    1992-02-01

    Ocean produced reduced sulfur compounds including dimethylsulfide (DMS), hydrogen sulfide (H{sub 2}S), carbon disulfide (CS{sub 2}), methyl mercaptan (CH{sub 3}CH) and carbonyl sulfide (OCS) deliver a sulfur burden to the atmosphere which is roughly equal to sulfur oxides produced by fossil fuel combustion. These species and their oxidation products dimethyl sulfoxide (DMSO), dimethyl sulfone (DMSO{sub 2}) and methane sulfonic acid (MSA) dominate aerosol and CCN production in clean marine air. Furthermore, oxidation of reduced sulfur species will be strongly influenced by NO{sub x}/O{sub 3} chemistry in marine atmospheres. The multiphase chemical processes for these species must be understood in order to study the evolving role of combustion produced sulfur oxides over the oceans. We have measured the chemical and physical parameters affecting the uptake of reduced sulfur compounds, their oxidation products, ozone, and nitrogen oxides by the ocean's surface, and marine clouds, fogs, and aerosols. These parameters include: gas/surface mass accommodation coefficients; physical and chemically modified (effective) Henry's law constants; and surface and liquid phase reaction constants. These parameters are critical to understanding both the interaction of gaseous trace species with cloud and fog droplets and the deposition of trace gaseous species to dew covered, fresh water and marine surfaces.

  8. The rate of 45Ca uptake by two corals species at waters of Burung island, Bangka-Belitung province

    International Nuclear Information System (INIS)

    Zulkifli Dahlan; Gusti Diansyah; T Zia Ulqodry; Ania Citraresmini

    2010-01-01

    Coral reefs transplantation is the most technique used for coral reefs rehabilitation, at the present. Recently the 45 Ca technique has been using for determining growth appearances in corals because of its ability to calculate the calcification process. For this reason, the study on the rate of 45 Ca uptake by natural corals Acropora Formosa and Acropora nobilis was carried out between June and December 2009 at the waters of Burung Island, Bangka-Belitung Province. The coral fragments of about 5 cm were harvested and put into a PVC container filled with 2 liters of fresh sea water, then incubated with 45 CaCl 2 solutions with an activity of 11.04 μCi/ml for 8 hour under fluorescent light. After the incubation, the “labeled” coral fragments were transplanted to where they have been taken from, and after such period will be re-harvested to determine their 45 Ca uptake content. The results showed that the 45 Ca technique was a reliable method to calculate the rate 45 Ca uptake by coral fragments, which were studied in different depths and time periods of light exposure. There was a significant difference in the 45 Ca uptake by the two different coral species. A. Formosa up took more 45 Ca than A. nobilis did. The highest 45 Ca uptake was shown by A. Formosa at 5 m. This was true for all the lengths of time to light exposure (1, 3, 5 and 7 hours). Different pattern of 45 Ca uptake showed by A. nobilisat 10 m depth, where it could be recognized that after a drop of 45 Ca the uptake increase continuously until the end of the light exposure (7 hours). The difference in 45 Ca uptake between the coral fragments is assumed to be influence by light and the algae species living symbiotically with the coral species that will further influence the CO 2 -fixation. This process will influence the calcification process, which is expressed in 45 Ca uptake. Further studies should be carried out to exactly gathered data of all the factors which could influence the calcification

  9. Effect of biochar on reclaimed tidal land soil properties and maize (Zea mays L.) response.

    Science.gov (United States)

    Kim, Hyuck-Soo; Kim, Kwon-Rae; Yang, Jae E; Ok, Yong Sik; Owens, Gary; Nehls, Thomas; Wessolek, Gerd; Kim, Kye-Hoon

    2016-01-01

    Reclaimed tidal land soil (RTLS) often contains high levels of soluble salts and exchangeable Na that can adversely affect plant growth. The current study examined the effect of biochar on the physicochemical properties of RTLS and subsequently the influence on plant growth performance. Rice hull derived biochar (BC) was applied to RTLS at three different rates (1%, 2%, and 5% (w/w)) and maize (Zea mays L.) subsequently cultivated for 6weeks. While maize was cultivated, 0.1% NaCl solution was supplied from the bottom of the pots to simulate the natural RTLS conditions. Biochar induced changes in soil properties were evaluated by the water stable aggregate (WSA) percentage, exchangeable sodium percentage (ESP), soil organic carbon contents, cation exchange capacity, and exchangeable cations. Plant response was measured by growth rate, nutrient contents, and antioxidant enzyme activity of ascorbate peroxidase (APX) and glutathione reductase (GR). Application of rice hull derived biochar increased the soil organic carbon content and the percentage of WSA by 36-69%, while decreasing the ESP. The highest dry weight maize yield was observed from soil which received 5% BC (w/w), which was attributed to increased stability of water-stable aggregates and elevated levels of phosphate in BC incorporated soils. Moreover, increased potassium, sourced from the BC, induced mitigation of Na uptake by maize and consequently, reduced the impact of salt stress as evidenced by overall declines in the antioxidant activities of APX and GR. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. [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.

  11. Foliar trichome- and aquaporin-aided water uptake in a drought-resistant epiphyte Tillandsia ionantha Planchon.

    Science.gov (United States)

    Ohrui, T; Nobira, H; Sakata, Y; Taji, T; Yamamoto, C; Nishida, K; Yamakawa, T; Sasuga, Y; Yaguchi, Y; Takenaga, H; Tanaka, Shigeo

    2007-12-01

    The atmospheric epiphyte Tillandsia ionantha is capable of surviving drought stress for 6 months or more without any exogenous water supply via an as of yet to be determined mechanism. When plants were soaked in water for 3 h, leaves absorbed a remarkably large amount of water (30-40% on the basis of fresh weight), exhibiting a bimodal absorption pattern. Radiolabeled water was taken up by the leaves by capillary action of the epidermal trichomes within 1 min (phase 1) and then transported intracellularly to leaf tissues over 3 h (phase 2). The removal of epidermal trichome wings from leaves as well as rinsing leaves with water significantly lowered the extracellular accumulation of water on leaf surfaces. The intracellular transport of water was inhibited by mercuric chloride, implicating the involvement of a water channel aquaporin in second-phase water absorption. Four cDNA clones (TiPIP1a, TiPIP1b, TiPIP1c, and TiPIP2a) homologous to PIP family aquaporins were isolated from the leaves, and RT-PCR showed that soaking plants in water stimulated the expression of TiPIP2a mRNA, suggesting the reinforcement in ability to rapidly absorb a large amount of water. The expression of TiPIP2a complementary RNA in Xenopus oocytes enhanced permeability, and treatment with inhibitors suggested that the water channel activity of TiPIP2a protein was regulated by phosphorylation. Thus, the high water uptake capability of T. ionantha leaves surviving drought is attributable to a bimodal trichome- and aquaporin-aided water uptake system based on rapid physical collection of water and subsequent, sustained chemical absorption.

  12. Effect of water management, tillage options and phosphorus status on arsenic uptake in rice.

    Science.gov (United States)

    Talukder, A S M H M; Meisner, C A; Sarkar, M A R; Islam, M S

    2011-05-01

    High arsenic (As) concentrations in soil may lead to elevated concentrations of arsenic in agricultural products. Field experiments were conducted to examine the effects of water management (WM) and Phosphorus (P) rates on As uptake, rice growth, yield and yield attributes of winter (boro) and monsoon (aman) rice in an As contaminated soil-water at Gobindagonj, Gaibandha, Bangladesh in 2004 and 2005. Significantly, the highest average grain yields (6.88±0.07 t ha(-1) in boro 6.38±0.06 t ha(-1) in aman) were recorded in permanent raised bed (PRB; aerobic WM: Eh=+360 mV) plus 100% P amendment. There was a 12% yield increase over conventional till on flat (CTF; anaerobic WM: Eh=-56 mV) at the same P level. In boro, the As content in grain and As content in straw were about 3 and 6 times higher in CTF compared to PRB, respectively. The highest total As content (0.646±0.01 ppm in grain and 10.93±0.19 ppm in straw) was recorded under CTF, and the lowest total As content (0.247±0.01 and 1.554±0.09 ppm in grain and straw, respectively) was recorded under PRB (aerobic WM). The results suggest that grain and straw As are closely associated in boro rice. The furrow irrigation approach of the PRB treatments consistently reduced irrigation input by 29-31% for boro and 27-30% for aman rice relative to CTF treatments in 2004 and 2005, respectively, thus reducing the amount of As added to the soil from the As-contaminated irrigation water. Yearly, 30% less As was deposited to the soil compared to CTF system through irrigation water during boro season. High As concentrations in grain and straw in rice grown using CTF in the farmers' field, and the fact that using PRB reduced grain As concentrations to value less than half of the proposed food hygiene standard. Copyright © 2010 Elsevier Inc. All rights reserved.

  13. Combined effect of chitosan and water activity on growth and fumonisin production by Fusarium verticillioides and Fusarium proliferatum on maize-based media.

    Science.gov (United States)

    Ferrochio, Laura V; Cendoya, Eugenia; Zachetti, Vanessa G L; Farnochi, Maria C; Massad, Walter; Ramirez, Maria L

    2014-08-18

    The objectives of the present study were to determine the in vitro efficacy of chitosan (0.5, 1.0, 2.0 and 3.0mg/mL) under different water availabilities (0.995, 0.99, 0.98, 0.96 and 0.93) at 25°C on lag phase, growth rate and fumonisin production by isolates of Fusarium verticillioides and Fusarium proliferatum. The presence of chitosan affected growth and fumonisin production, and this effect was dependent on the dose and aW treatment used. The presence of chitosan increased the lag phase, and reduced the growth rate of both Fusarium species significantly at all concentrations used, especially at 0.93 aW. Also, significant reduction of fumonisin production was observed in both Fusarium species at all conditions assayed. The present study has shown the combined effects of chitosan and aW on growth and fumonisin production by the two most important Fusarium species present on maize. Low molecular weight (Mw) chitosan with more than 70% of degree of deacetylation (DD) at 0.5mg/mL was able to significantly reduce growth rate and fumonisin production on maize-based media, with maximum levels of reduction in both parameters obtained at the highest doses used. As fumonisins are unavoidable contaminants in food and feed chains, their presence needs to be reduced to minimize their effects on human and animal health and to diminish the annual market loss through rejected maize. In this scenario post-harvest use of chitosan could be an important alternative treatment. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Water Leakage and Nitrate Leaching Characteristics in the Winter Wheat–Summer Maize Rotation System in the North China Plain under Different Irrigation and Fertilization Management Practices

    Directory of Open Access Journals (Sweden)

    Shufeng Chen

    2017-02-01

    Full Text Available Field experiments were carried out in Huantai County from 2006 to 2008 to evaluate the effects of different nitrogen (N fertilization and irrigation management practices on water leakage and nitrate leaching in the dominant wheat–maize rotation system in the North China Plain (NCP. Two N fertilization (NF1, the traditional one; NF2, fertilization based on soil testing and two irrigation (IR1, the traditional one; IR2, irrigation based on real-time soil water content monitoring management practices were designed in the experiments. Water and nitrate amounts leaving the soil layer at a depth of 2.0 m below the soil surface were calculated and compared. Results showed that the IR2 effectively reduced water leakage and nitrate leaching amounts in the two-year period, especially in the winter wheat season. Less than 10 percent irrigation water could be saved in a dry winter wheat season, but about 60 percent could be saved in a wet winter wheat season. Besides, 58.8 percent nitrate under single NF2IR1 and 85.2 percent under NF2IR2 could be prevented from leaching. The IR2 should be considered as the best management practice to save groundwater resources and prevent nitrate from leaching. The amounts of N input play a great role in affecting nitrate concentrations in the soil solutions in the winter wheat–summer maize rotation system. The NF2 significantly reduced N inputs and should be encouraged in ordinary agricultural production. Thus, nitrate leaching and groundwater contamination could be alleviated, but timely N supplement might be needed under high precipitation condition.

  15. Chemopreventive effects of free and bound phenolics associated to steep waters (nejayote) obtained after nixtamalization of different maize types.

    Science.gov (United States)

    Rojas-García, Carlos; García-Lara, Silverio; Serna-Saldivar, Sergio O; Gutiérrez-Uribe, Janet A

    2012-03-01

    Free and bound phenolics extracts from nejayote solids were obtained after optimally lime-cooking blue, normal white, red, normal yellow, high-carotenoid and quality protein maize types. The extraction yield ranged from 4.47 to 10.05%. Bound phenolics extracts had higher content of total phenolics, antioxidant activity and ferulic acid compared to the free phenolics extracts. In general, free phenolics extracts were less cytotoxic than the bound phenolics counterparts. Bound phenolics extracts had higher induction of quinone reductase (QR) and particularly the normal yellow nejayote exerted the highest chemopreventive index tested in Hepa1c1c7 cells. When tested for monofunctional phase 2 induction capacity in BPrc1 cells, the bound phenolics extracts of blue, normal white and quality protein nejayotes were better inducers than the normal yellow counterpart. Particularly, the free phenolics extract of the white maize nejayote induced BPrc1 cells QR and exerted a higher chemopreventive index compared to the bound phenolics extract. Therefore, the nejayote of the normal white maize was the best source of monofunctional phase 2 enzyme inducers.

  16. Quantification of water uptake by arbuscular mycorrhizal hyphae and its significance for leaf growth, water relations, and gas exchange of barley subjected to drought stress.

    Science.gov (United States)

    Khalvati, M A; Hu, Y; Mozafar, A; Schmidhalter, U

    2005-11-01

    Arbuscular mycorrhizal fungi alleviate drought stress in their host plants via the direct uptake and transfer of water and nutrients through the fungal hyphae to the host plants. To quantify the contribution of the hyphae to plant water uptake, a new split-root hyphae system was designed and employed on barley grown in loamy soil inoculated with Glomus intraradices under well-watered and drought conditions in a growth chamber with a 14-h light period and a constant temperature (15 degrees C; day/night). Drought conditions were initiated 21 days after sowing, with a total of eight 7-day drying cycles applied. Leaf water relations, net photosynthesis rates, and stomatal conductance were measured at the end of each drying cycle. Plants were harvested 90 days after sowing. Compared to the control treatment, the leaf elongation rate and the dry weight of the shoots and roots were reduced in all plants under drought conditions. However, drought resistance was comparatively increased in the mycorrhizal host plants, which suffered smaller decreases in leaf elongation, net photosynthetic rate, stomatal conductance, and turgor pressure compared to the non-mycorrhizal plants. Quantification of the contribution of the arbuscular mycorrhizal hyphae to root water uptake showed that, compared to the non-mycorrhizal treatment, 4 % of water in the hyphal compartment was transferred to the root compartment through the arbuscular mycorrhizal hyphae under drought conditions. This indicates that there is indeed transport of water by the arbuscular mycorrhizal hyphae under drought conditions. Although only a small amount of water transport from the hyphal compartment was detected, the much higher hyphal density found in the root compartment than in the hyphal compartment suggests that a larger amount of water uptake by the arbuscular mycorrhizal hyphae may occur in the root compartment.

  17. 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".

  18. Comparative uptake of gamma-emitting fission product nuclides by plants

    International Nuclear Information System (INIS)

    D'souza, T.J.; Mistry, K.B.

    1974-01-01

    The comparative uptake of long-lived gamma-emitting fission product nuclides 106 Ru, 125 Sb, 137 Cs and 144 Ce, present in global fallout from nuclear explosions, by maize (Zea mays L) plants was examined in water culture experiments. Over identical duration of plant growth, the extent of accumulation of the radionuclides in aerial tissues was in the following decreasing order: 137 Cs >, 125 Sb >, 106 Ru > and 144 Ce. In roots, however, the retention of 144 Ce and 106 Ru was greater than that of 137 Cs and 125 Sb. Complementary studies with maize and rice (Oryza sativa L) grown on two contrasting soil types, namely, laterite and black clay loam indicated that 137 Cs uptake by plants was markedly greater than that of the other radionuclides in both soil types. Plant uptake of 106 Ru and 125 Sb was significantly higher than that of 144 Ce in the black soil. In the laterite, however, 144 Ce uptake far exceeded that of 106 Ru and 125 Sb. In general, maize removed higher amounts of the radionuclides than rice from both soil types. (author)

  19. Does water chemistry affect the dietary uptake and toxicity of silver nanoparticles by the freshwater snail Lymnaea stagnalis?

    International Nuclear Information System (INIS)

    Oliver, Ana López-Serrano; Croteau, Marie-Noële; Stoiber, Tasha L.; Tejamaya, Mila; Römer, Isabella; Lead, Jamie R.; Luoma, Samuel N.

    2014-01-01

    Silver nanoparticles (AgNPs) are widely used in many applications and likely released into the aquatic environment. There is increasing evidence that Ag is efficiently delivered to aquatic organisms from AgNPs after aqueous and dietary exposures. Accumulation of AgNPs through the diet can damage digestion and adversely affect growth. It is well recognized that aspects of water quality, such as hardness, affect the bioavailability and toxicity of waterborne Ag. However, the influence of water chemistry on the bioavailability and toxicity of dietborne AgNPs to aquatic invertebrates is largely unknown. Here we characterize for the first time the effects of water hardness and humic acids on the bioaccumulation and toxicity of AgNPs coated with polyvinyl pyrrolidone (PVP) to the freshwater snail Lymnaea stagnalis after dietary exposures. Our results indicate that bioaccumulation and toxicity of Ag from PVP-AgNPs ingested with food are not affected by water hardness and by humic acids, although both could affect interactions with the biological membrane and trigger nanoparticle transformations. Snails efficiently assimilated Ag from the PVP-AgNPs mixed with diatoms (Ag assimilation efficiencies ranged from 82 to 93%). Rate constants of Ag uptake from food were similar across the entire range of water hardness and humic acid concentrations. These results suggest that correcting regulations for water quality could be irrelevant and ineffective where dietary exposure is important. - Highlights: • AgNP coated with polyvinyl pyrrolidone (PVP), PVP-AgNP were efficiently assimilated by Lymnaea stagnalis. • Water chemistry has no influence on the dietary uptake of PVP-AgNP by snails. - L. Stagnalis assimilated PVP-AgNPs efficiently from food and water chemistry had no influence on their uptake and toxicity

  20. HYDRUS Simulation of Sustainable Brackish Water Irrigation in a Winter Wheat-Summer Maize Rotation System in the North China Plain

    Directory of Open Access Journals (Sweden)

    Kangkang He

    2017-07-01

    Full Text Available Freshwater resources in the North China Plain (NCP are near depletion due to the unceasing overexploitation of deep groundwater, by far the most significant source of freshwater in the region. To deal with the deepening freshwater crisis, brackish water (rich but largely unused water in agriculture is increasingly being used in irrigation in the region. However, inappropriate irrigation with brackish water could lead to soil salinization and cropland degradation. To evaluate such negative impacts, the HYDRUS-1D model was used to simulate soil salt transport and accumulation under 15 years of irrigation with brackish water. The irrigation scenarios included brackish water irrigation during the wintering and jointing stages of winter wheat and then freshwater irrigation just before the sowing of summer maize. Freshwater irrigation was done to leach out soil salts, which is particularly vital in dry years. For the littoral region of the plain, HYDRUS-ID was used to simulate the irrigated cropping system stated above for a total period of 15 years. The results showed that it was feasible to use brackish water twice in one year, provided freshwater irrigation was performed before sowing summer maize. Freshwater irrigation, in conjunction with precipitation, leached out soil salts from the 100 cm root-zone depth. The maximum salt accumulation was in the 160–220 cm soil layer, which ensured that root-zone soil was free of restrictive salinity for crop growth. Precipitation was a critical determinant of the rate and depth leaching of soil salt. Heavy rainfall (>100 mm caused significant leaching of soluble salts in the 0–200 cm soil profile. Salt concentration under brackish water irrigation had no significant effect on the variations in the trend of soil salt transport in the soil profile. The variations of soil salinity were mainly affected by hydrological year type, for which the buried depth of soil salt was higher in wet years than in dry years

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

    Science.gov (United States)

    Miner, Grace L; Bauerle, William L

    2017-09-01

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

  2. Direct uptake of cobalt 60 by the carp (Cyprinus carpio L.) following experimental chronic or cyclical contamination of water

    International Nuclear Information System (INIS)

    Amiard-Triquet, C.; Foulquier, L.

    1978-01-01

    Irrespective of the nature of experimental cobalt 60 contamination (chronic or cyclical), the activity level in the carp was highest after 32 or 35 days when the concentration factor reached 3. An analysis of cobalt 60 distribution shows preferential uptake by the kidneys. It therefore seems unlikely that the discharge rate of effluents from the nuclear industry and the resulting variations of radioactivity levels in the water significantly modify the impact of contamination on aquatic organisms [fr

  3. Measuring and modeling three-dimensional water uptake of a growing faba bean (Vicia faba) within a soil column

    Science.gov (United States)

    Huber, Katrin; Koebernick, Nicolai; Kerkhofs, Elien; Vanderborght, Jan; Javaux, Mathieu; Vetterlein, Doris; Vereecken, Harry

    2014-05-01

    A faba bean was grown in a column filled with a sandy soil, which was initially close to saturation and then subjected to a single drying cycle of 30 days. The column was divided in four hydraulically separated compartments using horizontal paraffin layers. Paraffin is impermeable to water but penetrable by roots. Thus by growing deeper, the roots can reach compartments that still contain water. The root architecture was measured every second day by X-ray CT. Transpiration rate, soil matric potential in four different depths, and leaf area were measured continously during the experiment. To investigate the influence of the partitioning of available soil water in the soil column on water uptake, we used R-SWMS, a fully coupled root and soil water model [1]. We compared a scenario with and without the split layers and investigated the influence on root xylem pressure. The detailed three-dimensional root architecture was obtained by reconstructing binarized root images manually with a virtual reality system, located at the Juelich Supercomputing Centre [2]. To verify the properties of the root system, we compared total root lengths, root length density distributions and root surface with estimations derived from Minkowski functionals [3]. In a next step, knowing the change of root architecture in time, we could allocate an age to each root segment and use this information to define age dependent root hydraulic properties that are required to simulate water uptake for the growing root system. The scenario with the split layers showed locally much lower pressures than the scenario without splits. Redistribution of water within the unrestricted soil column led to a more uniform distribution of water uptake and lowers the water stress in the plant. However, comparison of simulated and measured pressure heads with tensiometers suggested that the paraffin layers were not perfectly hydraulically isolating the different soil layers. We could show compensation efficiency of

  4. Simulation of irrigation and nitrogen fertilization management of maize under edaphic conditions of south of Havana

    International Nuclear Information System (INIS)

    Lopez Seijas, Teresa; Cid, G.; Gonzalez, F.; Jorge, Y.; Chaterlan, Y.; Giralt, E.; Rodriguez, R.; Duennas, G.

    1999-01-01

    The main objective of this work is to validate the crop simulation model STICS for the soil and climate conditions of south of Havana, especially for the water and nitrogen balances on Maize crop on Ferralitic soil, For this purpose was used all the available information from field experiments carried out in the Experimental Stations of the Irrigation and Drainage and Soil Research Institutes, both on south of Havana, The comparison between the simulation and observed values showed a good fitness for the variables related to the crop water uptake, while for the soil water content when the root water uptake flux is minimum and the soil water redistribution flux is maximum wasn't good, The soil nitrogen balance was adjusted from the optimization of the parameters related to the mineralization velocity of soil organic nitrogen, Nevertheless is necessary to complete this study involving other climate conditions and water and nitrogen managements to define the optimum strategy for irrigation and fertilization of Maize crop on the studied conditions,

  5. Organic acids enhance bioavailability of tetracycline in water to Escherichia coli for uptake and expression of antibiotic resistance.

    Science.gov (United States)

    Zhang, Yingjie; Boyd, Stephen A; Teppen, Brian J; Tiedje, James M; Li, Hui

    2014-11-15

    Tetracyclines are a large class of antimicrobials used most extensively in livestock feeding operations. A large portion of tetracyclines administered to livestock is excreted in manure and urine which is collected in waste lagoons. Subsequent land application of these wastes introduces tetracyclines into the soil environment, where they could exert selective pressure for the development of antibiotic resistance genes in bacteria. Tetracyclines form metal-complexes in natural waters, which could reduce their bioavailability for bacterial uptake. We hypothesized that many naturally-occurring organic acids could effectively compete with tetracyclines as ligands for metal cations, hence altering the bioavailability of tetracyclines to bacteria in a manner that could enhance the selective pressure. In this study, we investigated the influence of acetic acid, succinic acid, malonic acid, oxalic acid and citric acid on tetracycline uptake from water by Escherichia coli bioreporter construct containing a tetracycline resistance gene which induces the emission of green fluorescence when activated. The presence of the added organic acid ligands altered tetracycline speciation in a manner that enhanced tetracycline uptake by E. coli. Increased bacterial uptake of tetracycline and concomitant enhanced antibiotic resistance response were quantified, and shown to be positively related to the degree of organic acid ligand complexation of metal cations in the order of citric acid > oxalic acid > malonic acid > succinic acid > acetic acid. The magnitude of the bioresponse increased with increasing aqueous organic acid concentration. Apparent positive relation between intracellular tetracycline concentration and zwitterionic tetracycline species in aqueous solution indicates that (net) neutral tetracycline is the species which most readily enters E. coli cells. Understanding how naturally-occurring organic acid ligands affect tetracycline speciation in solution, and how speciation

  6. [Effects of plastic film mulching and rain harvesting modes on chlorophyll fluorescence characteristics, yield and water use efficiency of dryland maize].

    Science.gov (United States)

    Li, Shang-Zhong; Fan, Ting-Lu; Wang, Yong; Zhao, Gang; Wang, Lei; Tang, Xiao-Ming; Dang, Yi; Zhao, Hui

    2014-02-01

    The differences on chlorophyll fluorescence parameters, yield and water use efficiency of dryland maize were compared among full plastic film mulching on double ridges and planting in catchment furrows (FFDRF), half plastic film mulching on double ridges and planting in catchment furrows (HFDRF), plastic film mulching on ridge and planting in film-side (FS), and flat planting with no plastic film mulching (NM) under field conditions in dry highland of Loess Plateau in 2007-2012. The results showed that fluorescence yield (Fo), the maximum fluorescence yield (Fm), light-adapted fluorescence yield when PS II reaction centers were totally open (F), light-adapted fluorescence yield when PS II reaction centers closed (Fm'), the maximal photochemical efficiency of PS II (Fv/Fm), the actual photochemical efficiency of PS II in the light (Phi PS II), the relative electron transport rate (ETR), photochemical quenching (qP) and non-photochemical quenching (qN) in maize leaves of FFDRF were higher than that of control (NM), and the value of 1-qP was lower than that of control, at 13:00, chlorophyll fluorescence parameters values of FFDRF was significantly higher than control, which were increased by 5.3%, 56.8%, 10.7%, 36.3%, 23.6%, 56.7%, 64.4%, 45.5%, 23.6% and -55.6%, respectively, compared with the control. Yield and water use efficiency of FFDRF were the highest in every year no matter dry year, normal year, humid year and hail disaster year. Average yield and water use efficiency of FFDRF were 12,650 kg x hm(-2) and 40.4 kg x mm(-1) x hm(-2) during 2007-2012, increased by 57.8% and 61.6% compared with the control, respectively, and also significantly higher compared with HFDRF and PS. Therefore, it was concluded that FFDRF had significantly increased the efficiency of light energy conversion and improved the production capacity of dryland maize.

  7. Effects of long-term individual and combined water and temperature stress on the growth of rice, wheat and maize: relationship with morphological and physiological acclimation.

    Science.gov (United States)

    Perdomo, Juan Alejandro; Conesa, Miquel À; Medrano, Hipólito; Ribas-Carbó, Miquel; Galmés, Jeroni

    2015-10-01

    This study evaluates the long-term individual and combined effects of high temperature (HT) and water deficit (WD) stress on plant growth, leaf gas-exchange and water use efficiency in cultivars of the three most important crops worldwide, rice, wheat and maize. Total plant biomass (B t ) accumulation decreased under all treatments, being the combined HT-WD treatment the most detrimental in all three species. Although decreases in B t correlated with adjustments in biomass allocation patterns (i.e. the leaf area ratio), most of the variation observed in B t was explained by changes in leaf gas exchange parameters. Thus, integrated values of leaf carbon balance obtained from daily course measurements of photosynthesis and respiration were better predictors of plant growth than the instantaneous measurements of leaf gas exchange. Leaf water use efficiency, assessed both by gas exchange and carbon isotope measurements, was negatively correlated with B t under WD, but not under the combined WD and HT treatment. A comparative analysis of the negative effects of single and combined stresses on the main parameters showed an additive component for WD and HT in rice and maize, in contrast to wheat. Overall, the results of the specific cultivars included in the study suggest that the species native climate plays a role shaping the species acclimation potential to the applied stresses. In this regard, wheat, originated in a cold climate, was the most affected species, which foretells a higher affectation of this crop due to climate change. © 2014 Scandinavian Plant Physiology Society.

  8. Oxygen uptake during Wingate tests for arms and legs in swimmers and water polo players

    Directory of Open Access Journals (Sweden)

    Colantonio Emilson

    2003-01-01

    Full Text Available OBJECTIVE: The aim of the present study is to compare the values of the maximal oxygen uptake (O2 max during two consecutive bouts in Wingate tests for arms and legs in swimmers (S and water polo players (WP. METHODS: Sample - seven national level athletes (4 S and 3 WP, age 17,90 ± 2,14 years, body mass 71,41 ± 6,84 kg, height 176,65 ± 7,02 cm, % body fat 13,23 ± 4,18. Two Wingate bouts with 30 sec each with 3 min interval between them, for arms and legs in alternated days. Oxygen uptake: breath-by-breath using the gas analysis system K4 b² Cosmed. Statistical analysis: Wilcoxon test for dependent variables and Kolmogorov-Smirnov test for independent variables. RESULTS: The mean values found at the O2 peak (PO2, mean power (MP and peak power (PP for each bout of the Wingate test, for arms and legs. For Arms: PO2 = 55.16 ± 5.72 ml.kg-1.min-1, MP = 5.28 ± 0.59 watts.kg-1 and PP = 6.71 ± 0.88 watts.kg-1 got in the first bout (1st Arms and PO2 = 60.12 ± 6.10 ml.kg-1.min-1, MP = 5.03 ± 0.40 watts.kg-1 and PP = 6.25 ± 0.51 watts.kg-1, got in the second bout (2nd Arms. For legs: PO2 = 55.66 ± 6.85 ml.kg-1.min-1, MP = 4.75 ± 1.79 watts.kg-1 and PP = 7.44 ± 1.96 watts.kg-1 got in the first bout (1st Legs and PO2 = 62.09 ± 5.99 ml.kg-1.min-1, MP = 4.28 ± 1.47 watts.kg-1 and PP = 6.68 ± 1.63 watts.kg-1 got in the second bout (2nd Legs. DISCUSSION AND CONCLUSION: All variables studied did not present significant difference among arms and legs, as much the first as the second bout for arms for PO2 (p < 0.05. There was no difference between the PM mean values of the first and the second bout. But the mean of the second bout of legs was significant smaller than the first bout (p < 0.05. For the PP variable there was no difference among the mean values to the first and second bout as much for arms as for legs. It looks like to exist larger magnitude to O2 adjustment for arms than legs, that could be associated to specific demands to which S

  9. The influence of drought on the water uptake by Scots pines (Pinus sylvestris L. at different positions in the tree stand

    Directory of Open Access Journals (Sweden)

    Boczoń Andrzej

    2015-12-01

    Full Text Available Periodically occurring drought is typical for the climate of Poland. In habitats supplied exclusively with rain water, tree stands are frequently exposed to the negative effects of water deficit in the soil. The aim of this study was to examine the water uptake and consumption of two individual Scots pine trees under drought conditions. The trees were located at different positions within the stand and at the time of study were over 150 years old. Soil moisture, availability of soil water and the quantity of water uptake by the individual trees were examined by measuring the water velocity inside the trunks (Thermal Dissipation Probe method.

  10. Do Reductions in Dry Season Transpiration Allow Shallow Soil Water Uptake to Persist in a Tropical Lower Montane Cloud Forest?

    Science.gov (United States)

    Munoz Villers, L. E.; Holwerda, F.; Alvarado-Barrientos, M. S.; Goldsmith, G. R.; Geissert Kientz, D. R.; González Martínez, T. M.; Dawson, T. E.

    2016-12-01

    Tropical montane cloud forests (TMCF) are ecosystems particularly sensitive to climate change; however, the effects of warmer and drier conditions on TMCF water cycling remain poorly understood. To investigate the plant functional response to reduced water availability, we conducted a study during the mid to late dry season (2014) in the lower limit (1,325 m asl) of the TMCF belt (1200-2500 m asl) in central Veracruz, Mexico. The temporal variation of transpiration rates of dominant upper canopy and mid-story tree species, depth of water uptake, as well as tree water sources were examined using micrometeorological, sapflow and soil moisture measurements, in combination with data on stable isotope (δ18O and δ2H) composition of rain, tree xylem, soil (bulk and low suction-lysimeter) and stream water. The sapflow data suggest that crown conductances decreased as temperature and vapor pressure deficit increased, and soil moisture decreased from the mid to late dry season. Across all samplings (January 21, April 12 and 26), upper canopy species (Quercus spp.) showed more depleted (negative) isotope values compared to mid-story trees (Carpinus tropicalis). Overall, we found that the evaporated soil water pool was the main source for the trees. Furthermore, our MixSIAR Bayesian mixing model results showed that the depth of tree water uptake changed over the course of the dry season. Unexpectedly, a shift in water uptake from deeper (60-120 cm depth) to shallower soil water (0-30 cm) sources was observed, coinciding with the decreases in transpiration rates towards the end of the dry season. A larger reduction in deep soil water contributions was observed for upper canopy trees (from 70±14 to 22±15%) than for mid-story species (from 10±13 to 7±10%). The use of shallow soil water by trees during the dry season seems consistent with the greater root biomass and higher macronutrient concentrations found in the first 10 cm of the soil profiles. These findings are an

  11. 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...

  12. Modeling and assessing field irrigation water use in a canal system of Hetao, upper Yellow River basin: Application to maize, sunflower and watermelon

    Science.gov (United States)

    Ren, Dongyang; Xu, Xu; Hao, Yuanyuan; Huang, Guanhua

    2016-01-01

    Water saving in irrigation is a key issue in the upper Yellow River basin. Excessive irrigation leads to water waste, water table rising and increased salinity. Land fragmentation associated with a large dispersion of crops adds to the agro-hydrological complexity of the irrigation system. The model HYDRUS-1D, coupled with the FAO-56 dual crop coefficient approach (dualKc), was applied to simulate the water and salt movement processes. Field experiments were conducted for maize, sunflower and watermelon crops in the command area of a typical irrigation canal system in Hetao Irrigation District during 2012 and 2013. The model was calibrated and validated in three crop fields using two-year experimental data. Simulations of soil moisture, salinity concentration and crop yield fitted well with the observations. The irrigation water use was then evaluated and results showed that large amounts of irrigation water percolated due to over-irrigation but their reuse through capillary rise was also quite large. That reuse was facilitated by the dispersion of crops throughout largely fragmented field, thus with fields reusing water percolated from nearby areas due to the rapid lateral migration of groundwater. Beneficial water use could be improved when taking this aspect into account, which was not considered in previous researches. The non-beneficial evaporation and salt accumulation into the root zone were found to significantly increase during non-growth periods due to the shallow water tables. It could be concluded that when applying water saving measures, close attention should be paid to cropping pattern distribution and groundwater control in association with irrigation scheduling and technique improvement.

  13. Osmosis-induced water uptake by Eurobitum bituminized radioactive waste and pressure development in constant volume conditions

    International Nuclear Information System (INIS)

    Mariën, A.; Mokni, N.; Valcke, E.; Olivella, S.; Smets, S.; Li, X.

    2013-01-01

    Highlights: ► The water uptake by Eurobitum is studied to judge the safety of geological disposal. ► High pressures of up to 20 MPa are measured in constant volume water uptake tests. ► The morphology of leached Eurobitum samples is studied with μCT and ESEM. ► The observations are reproduced by an existing CHM formulation for Eurobitum. - Abstract: The chemo-hydro-mechanical (CHM) interaction between swelling Eurobitum radioactive bituminized waste (BW) and Boom Clay is investigated to assess the feasibility of geological disposal for the long-term management of this waste. These so-called compatibility studies include laboratory water uptake tests at Belgian Nuclear Research Center SCK-CEN, and the development of a coupled CHM formulation for Eurobitum by the International Center for Numerical Methods and Engineering (CIMNE, Polytechnical University of Cataluña, Spain). In the water uptake tests, the osmosis-induced swelling, pressure increase and NaNO 3 leaching of small cylindrical BW samples (diameter 38 mm, height 10 mm) is studied under constant total stress conditions and nearly constant volume conditions; the actual geological disposal conditions should be intermediate between these extremes. Two nearly constant volume tests were stopped after 1036 and 1555 days to characterize the morphology of the hydrated BW samples and to visualize the hydrated part with microfocus X-ray Computer Tomography (μCT) and Environmental Scanning Electron Microscopy (ESEM). In parallel, a coupled CHM formulation is developed that describes chemically and hydraulically coupled flow processes in porous materials with salt crystals, and that incorporates a porosity dependent membrane efficiency, permeability and diffusivity. When Eurobitum BW is hydrated in (nearly) constant volume conditions, the osmosis-induced water uptake results in an increasing pressure to values that can be (in theory) as high as 42.8 MPa, being the osmotic pressure of a saturated NaNO 3

  14. Preparation and use of maize tassels' activated carbon for the adsorption of phenolic compounds in environmental waste water samples.

    Science.gov (United States)

    Olorundare, O F; Msagati, T A M; Krause, R W M; Okonkwo, J O; Mamba, B B

    2015-04-01

    The determination and remediation of three phenolic compounds bisphenol A (BPA), ortho-nitrophenol (o-NTP), parachlorophenol (PCP) in wastewater is reported. The analysis of these molecules in wastewater was done using gas chromatography (GC) × GC time-of-flight mass spectrometry while activated carbon derived from maize tassel was used as an adsorbent. During the experimental procedures, the effect of various parameters such as initial concentration, pH of sample solution, eluent volume, and sample volume on the removal efficiency with respect to the three phenolic compounds was studied. The results showed that maize tassel produced activated carbon (MTAC) cartridge packed solid-phase extraction (SPE) system was able to remove the phenolic compounds effectively (90.84-98.49%, 80.75-97.11%, and 78.27-97.08% for BPA, o-NTP, and PCP, respectively). The MTAC cartridge packed SPE sorbent performance was compared to commercially produced C18 SPE cartridges and found to be comparable. All the parameters investigated were found to have a notable influence on the adsorption efficiency of the phenolic compounds from wastewaters at different magnitudes.

  15. Uptake of Iodide From Water in Atlantic Halibut Larvae (Hippoglossus Hippoglossus L.)

    DEFF Research Database (Denmark)

    Moren, Mari; Sloth, Jens Jørgen; Hamre, Kristin

    2008-01-01

    The natural diet of marine fish larvae, copepods, contain 60-350 mg I kg(-1), while live feed used in commercial hatcheries have iodine concentrations in the range of 1 mg kg(-1). Seawater is also considered to be an important source of iodine for marine fish. The question asked in this study is ......M. The uptake was partly blocked by perchlorate (ClO3-) which is a known inhibitor of the sodium iodide symporter. This indicates that the Atlantic halibut larvae accumulate iodide through both specific and non-specific uptake pathways....

  16. Water Vapor, Temperature and Wind Profiles within Maize Canopy under in-Field Rainwater Harvesting with Wide and Narrow Runoff Strips

    Directory of Open Access Journals (Sweden)

    Weldemichael A. Tesfuhuney

    2013-11-01

    Full Text Available Micrometeorological measurements were used to evaluate heat and water vapor to describe the transpiration (Ev and soil evaporation (Es processes for wide and narrow runoff strips under in-field rainwater harvesting (IRWH system. The resulting sigmoid-shaped water vapor (ea in wide and narrow runoff strips varied in lower and upper parts of the maize canopy. In wide runoff strips, lapse conditions of ea extended from lowest measurement level (LP to the upper middle section (MU and inversion was apparent at the top of the canopy. The virtual potential temperature (θv profile showed no difference in middle section, but the lower and upper portion (UP had lower  in narrow, compared to wide, strips, and LP-UP changes of 0.6 K and 1.2 K were observed, respectively. The Ev and Es within the canopy increased the ea concentration as determined by the wind order of magnitude. The ea concentration reached peak at about 1.6 kPa at a range of wind speed value of 1.4–1.8 m∙s−1 and 2.0–2.4 m∙s−1 for wide and narrow treatments, respectively. The sparse maize canopy of the wide strips could supply more drying power of the air in response to atmospheric evaporative demand compared to narrow strips. This is due to the variation in air flow in wide and narrow runoff strips that change gradients in ea for evapotranspiration processes.

  17. The effects of water management on the CO2 uptake of Sphagnum moss in a reclaimed peatland

    Directory of Open Access Journals (Sweden)

    C.M. Brown

    2017-07-01

    Full Text Available To harvest Sphagnum on a cyclic basis and rapidly accumulate biomass, active water management is necessary. The goal of this study is to determine the hydrological conditions that will maximise CO2 uptake in Sphagnum farming basins following the moss-layer transfer technique. Plot CO2 uptake doubled from the first growing season to the second, but growth was not uniform across the site. Results indicate that the seasonal oscillations in water table (WT position were more important than actual WT position for estimating Sphagnum ground cover and CO2 uptake when the seasonal WT is shallow (< -25 cm. Plots with higher productivity had a WT range (seasonal maximum – minimum less than 15 cm, a WT position which did not fluctuate more than ± 7.5 cm, and a low WT standard deviation. Each basin was a CO2 source during the second growing season, and seasonal modelled NEE ranged from 107.1 to 266.8 g CO2 m-2. Decomposition from the straw mulch accounted for over half of seasonal respiration, and the site is expected to become a CO2 sink as the straw mulch decomposes and moss cover increases. This study highlights the importance of maintaining stable moisture conditions to increase Sphagnum growth and CO2 sink functions.

  18. An experimental set-up to study carbon, water, and nitrate uptake rates by hydroponically grown plants.

    Science.gov (United States)

    Andriolo, J L; Le Bot, J; Gary, C; Sappe, G; Orlando, P; Brunel, B; Sarrouy, C

    1996-01-01

    The experimental system described allows concomitant hourly measurements of CO2, H2O, and NO3 uptake rates by plants grown hydroponically in a greenhouse. Plants are enclosed in an airtight chamber through which air flows at a controlled speed. Carbon dioxide exchange and transpiration rates are determined from respective differences of concentrations of CO2 and water vapor of the air at the system inlet and outlet. This set-up is based on the "open-system" principle with improvements made on existing systems. For instance, propeller anemometers are used to monitor air flow rates in the chamber. From their signal it is possible to continuously adjust air speed to changing environmental conditions and plant activity. The air temperature inside the system therefore never rises above that outside. Water and NO3 uptake rates are calculated at time intervals from changes in the volume and the NO3 concentration of the nutrient solution in contact with the roots. The precise measurement of the volume of solution is achieved using a balance which has a higher precision than any liquid level sensors. Nitrate concentration is determined in the laboratory from aliquots of solution sampled at time intervals. A number of test runs are reported which validate the measurements and confirm undisturbed conditions within the system. Results of typical diurnal changes in CO2, H2O, and NO3 uptake rates by fruiting tomato plants are also presented.

  19. MzPIP2;1: An Aquaporin Involved in Radial Water Movement in Both Water Uptake and Transportation, Altered the Drought and Salt Tolerance of Transgenic Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Lin Wang

    Full Text Available Plants are unavoidably subjected to various abiotic stressors, including high salinity, drought and low temperature, which results in water deficit and even death. Water uptake and transportation play a critical role in response to these stresses. Many aquaporin proteins, localized at different tissues, function in various transmembrane water movements. We targeted at the key aquaporin in charge of both water uptake in roots and radial water transportation from vascular tissues through the whole plant.The MzPIP2;1 gene encoding a plasma membrane intrinsic protein was cloned from salt-tolerant apple rootstock Malus zumi Mats. The GUS gene was driven by MzPIP2;1 promoter in transgenic Arabidopsis. It indicated that MzPIP2;1 might function in the epidermal and vascular cells of roots, parenchyma cells around vessels through the stems and vascular tissues of leaves. The ectopically expressed MzPIP2;1 conferred the transgenic Arabidopsis plants enhanced tolerance to slight salt and drought stresses, but sensitive to moderate salt stress, which was indicated by root length, lateral root number, fresh weight and K+/Na+ ratio. In addition, the possible key cis-elements in response to salt, drought and cold stresses were isolated by the promoter deletion experiment.The MzPIP2;1 protein, as a PIP2 aquaporins subgroup member, involved in radial water movement, controls water absorption and usage efficiency and alters transgenic plants drought and salt tolerance.

  20. Visualization and quantification of weathering effects on capillary water uptake of natural building stones by using neutron imaging

    International Nuclear Information System (INIS)

    Raneri, Simona; Barone, Germana; Mazzoleni, Paolo; Rabot, Eva

    2016-01-01

    Building stones are frequently subjected to very intense degradation due to salt crystallization, often responsible for strong modifications of their pore network. These effects have a great influence on the mechanical properties and durability of the materials, and on the penetration of water. Therefore, the quantification and visualization of water absorption into the pore network of degraded stones could provide useful information to better understand the weathering process. In this study, neutron radiography has been used (1) to monitor and visualize in two dimensions the capillary water uptake in a Sicilian calcarenite widely used as building and replace stone (namely Sabucina stone) and (2) to quantify the water content distribution, as a function of time and weathering degree. Additionally, traditional experiments based on gravimetric methods have been performed, following the standard recommendations. Results demonstrated a change in the physical properties of Sabucina stones with the intensification of the degradation process, with severe effects on the capillary imbibition dynamics. The water penetration depth at the end of the experiment was substantially higher in the fresh than in the weathered stones. The water absorption kinetics was faster in the weathered samples, and the amount of water absorbed increased with the number of weathering cycles. Good agreement between classical and neutron imaging data has also been evidenced. However, neutron radiography has allowed retrieving additional spatial information on the water absorption process, and to better understand how salt weathering affects the petrophysical properties of the studied stone and how it influences then the stone response against water. (orig.)

  1. Visualization and quantification of weathering effects on capillary water uptake of natural building stones by using neutron imaging

    Energy Technology Data Exchange (ETDEWEB)

    Raneri, Simona; Barone, Germana; Mazzoleni, Paolo [University of Catania, Department of Biological, Geological and Environment Sciences, Catania (Italy); Rabot, Eva [Laboratoire Leon Brillouin (CNRS/CEA), Gif-Sur-Yvette (France)

    2016-11-15

    Building stones are frequently subjected to very intense degradation due to salt crystallization, often responsible for strong modifications of their pore network. These effects have a great influence on the mechanical properties and durability of the materials, and on the penetration of water. Therefore, the quantification and visualization of water absorption into the pore network of degraded stones could provide useful information to better understand the weathering process. In this study, neutron radiography has been used (1) to monitor and visualize in two dimensions the capillary water uptake in a Sicilian calcarenite widely used as building and replace stone (namely Sabucina stone) and (2) to quantify the water content distribution, as a function of time and weathering degree. Additionally, traditional experiments based on gravimetric methods have been performed, following the standard recommendations. Results demonstrated a change in the physical properties of Sabucina stones with the intensification of the degradation process, with severe effects on the capillary imbibition dynamics. The water penetration depth at the end of the experiment was substantially higher in the fresh than in the weathered stones. The water absorption kinetics was faster in the weathered samples, and the amount of water absorbed increased with the number of weathering cycles. Good agreement between classical and neutron imaging data has also been evidenced. However, neutron radiography has allowed retrieving additional spatial information on the water absorption process, and to better understand how salt weathering affects the petrophysical properties of the studied stone and how it influences then the stone response against water. (orig.)

  2. Narrowing Maize Yield Gaps Under Rain-fed conditions in Tanzania ...

    African Journals Online (AJOL)

    Abstract. The wide gap between potential and actual yields of maize in Tanzania, due low productivity is the major constraint to ... An International Journal of Basic and Applied Research ... for determining maize grain yield followed by water.

  3. Uptake of cobalt-60 from sea water and from labelled food by the common shrimp Crangon erangon (L.)

    International Nuclear Information System (INIS)

    Weers, A.W. van

    1975-01-01

    The role of two different modes of uptake in the accumulation of 60 Co by the common shrimp (Crangon crangon (L.)) is the subject of the present study. The results show that accumulation of 60 Co from sea water is a slow process. The concentration factor for whole animals reached in one month was only about 13. Most of the activity accumulated from water appears to be associated with the exoskeleton. As a consequence, moulting has a pronounced effect on the uptake pattern of 60 Co and on the subsequent retention of the radionuclide by shrimps kept in non-radioactive sea water. After single feeding of shrimps with labelled mussel flesh, 60 Co is retained according to an exponential function with a short-lived and a long-lived component. The short-lived component has a mean biological half-life of 1.2 days and accounts for about 80% of the initial activity. About 20% of the initial activity is lost with a mean biological half-life of about 10 days. After repeated feeding of labelled mussel flesh the short-lived component in the 60 Co retention is virtually absent. Cobalt-60 taken up with food is localized mainly in the digestive gland and the concentration in the edible muscles from the abdomen is relatively small. It is concluded from the present study that direct uptake from sea water will play only a minor role in the accumulation of 60 Co in the internal organs of the shrimp. 60 Co released into the marine environment will be taken up by shrimps mainly from food. The results indicate a rapid turnover of 60 Co in shrimps. (author)

  4. Crop water productivity under increasing irrigation capacities in Romania. A spatially-explicit assessment of winter wheat and maize cropping systems in the southern lowlands of the country

    Science.gov (United States)

    Dogaru, Diana

    2016-04-01

    Improved water use efficiency in agriculture is a key issue in terms of sustainable management and consumption of water resources in the context of peoples' increasing food demands and preferences, economic growth and agricultural adaptation options to climate variability and change. Crop Water Productivity (CWP), defined as the ratio of yield (or value of harvested crop) to actual evapotranspiration or as the ratio of yield (or value of harvested crop) to volume of supplied irrigation water (Molden et al., 1998), is a useful indicator in the evaluation of water use efficiency and ultimately of cropland management, particularly in the case of regions affected by or prone to drought and where irrigation application is essential for achieving expected productions. The present study investigates the productivity of water in winter wheat and maize cropping systems in the Romanian Plain (49 594 sq. km), an important agricultural region in the southern part of the country which is increasingly affected by drought and dry spells (Sandu and Mateescu, 2014). The scope of the analysis is to assess the gains and losses in CWP for the two crops, by considering increased irrigated cropland and improved fertilization, these being the most common measures potentially and already implemented by the farmers. In order to capture the effects of such measures on agricultural water use, the GIS-based EPIC crop-growth model (GEPIC) (Williams et al., 1989; Liu, 2009) was employed to simulate yields, seasonal evapotranspiration from crops and volume of irrigation water in the Romanian Plain for the 2002 - 2013 interval with focus on 2007 and 2010, two representative years for dry and wet periods, respectively. The GEPIC model operates on a daily time step, while the geospatial input datasets for this analysis (e.g. climate data, soil classes and soil parameters, land use) were harmonized at 1km resolution grid cell. The sources of the spatial data are mainly the national profile agencies

  5. Harnessing maize biodiversity

    Science.gov (United States)

    Maize is a remarkably diverse species, adapted to a wide range of climatic conditions and farming practices. The latitudinal range of maize is immense, ranging from 54°N in Alberta, Canada, to 45°S in the province of Chubut, Argentina. In terms of altitude, maize is cultivated from sea level to 4000...

  6. Maximum Plant Uptakes for Water, Nutrients, and Oxygen Are Not Always Met by Irrigation Rate and Distribution in Water-based Cultivation Systems.

    Science.gov (United States)

    Blok, Chris; Jackson, Brian E; Guo, Xianfeng; de Visser, Pieter H B; Marcelis, Leo F M

    2017-01-01

    Growing on rooting media other than soils in situ -i.e., substrate-based growing- allows for higher yields than soil-based growing as transport rates of water, nutrients, and oxygen in substrate surpass those in soil. Possibly water-based growing allows for even higher yields as transport rates of water and nutrients in water surpass those in substrate, even though the transport of oxygen may be more complex. Transport rates can only limit growth when they are below a rate corresponding to maximum plant uptake. Our first objective was to compare Chrysanthemum growth performance for three water-based growing systems with different irrigation. We compared; multi-point irrigation into a pond (DeepFlow); one-point irrigation resulting in a thin film of running water (NutrientFlow) and multi-point irrigation as droplets through air (Aeroponic). Second objective was to compare press pots as propagation medium with nutrient solution as propagation medium. The comparison included DeepFlow water-rooted cuttings with either the stem 1 cm into the nutrient solution or with the stem 1 cm above the nutrient solution. Measurements included fresh weight, dry weight, length, water supply, nutrient supply, and oxygen levels. To account for differences in radiation sum received, crop performance was evaluated with Radiation Use Efficiency (RUE) expressed as dry weight over sum of Photosynthetically Active Radiation. The reference, DeepFlow with substrate-based propagation, showed the highest RUE, even while the oxygen supply provided by irrigation was potentially growth limiting. DeepFlow with water-based propagation showed 15-17% lower RUEs than the reference. NutrientFlow showed 8% lower RUE than the reference, in combination with potentially limiting irrigation supply of nutrients and oxygen. Aeroponic showed RUE levels similar to the reference and Aeroponic had non-limiting irrigation supply of water, nutrients, and oxygen. Water-based propagation affected the subsequent

  7. Content and uptake of trace metals in benthic algae, Enteromorpha and Porphyra. II. Studies on the algae cultured in sea water supplemented with various metals

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, M.; Fujiyama, T.

    1977-01-01

    In the culture of Porphyra in sea water supplemented with metals, the uptakes of Mn and Cd were relatively high and increased in proportion to culture time when the metal concentration in water was high. Fe distributed evenly in all three parts of fronds. Mn was concentrated in surface and middle layers, while Cd was accumulated mainly in the middle layer and a little in the surface layer. In general the uptake was high in the middle layer. In the uptake of Mn there was a clear distinction between light and dark conditions, that is, Mn was absorbed only during light periods while Cd was absorbed regardless of light and dark periods.

  8. The effect of frequency-specific sound signals on the germination of maize seeds.

    Science.gov (United States)

    Vicient, Carlos M

    2017-07-25

    The effects of sound treatments on the germination of maize seeds were determined. White noise and bass sounds (300 Hz) had a positive effect on the germination rate. Only 3 h treatment produced an increase of about 8%, and 5 h increased germination in about 10%. Fast-green staining shows that at least part of the effects of sound are due to a physical alteration in the integrity of the pericarp, increasing the porosity of the pericarp and facilitating oxygen availability and water and oxygen uptake. Accordingly, by removing the pericarp from the seeds the positive effect of the sound on the germination disappeared.

  9. Evaluation of root water uptake in the ISBA-A-gs land surface model using agricultural yield statistics over France

    Science.gov (United States)

    Canal, N.; Calvet, J.-C.; Decharme, B.; Carrer, D.; Lafont, S.; Pigeon, G.

    2014-12-01

    The simulation of root water uptake in land surface models is affected by large uncertainties. The difficulty in mapping soil depth and in describing the capacity of plants to develop a rooting system is a major obstacle to the simulation of the terrestrial water cycle and to the representation of the impacts of drought. In this study, long time series of agricultural statistics are used to evaluate and constrain root water uptake models. The inter-annual variability of cereal grain yield and permanent grassland dry matter yield is simulated over France by the Interactions between Soil, Biosphere and Atmosphere, CO2-reactive (ISBA-A-gs) generic land surface model (LSM). The two soil profile schemes available in the model are used to simulate the above-ground biomass (Bag) of cereals and grasslands: a two-layer force-restore (FR-2L) bulk reservoir model and a multi-layer diffusion (DIF) model. The DIF model is implemented with or without deep soil layers below the root zone. The evaluation of the various root water uptake models is achieved by using the French agricultural statistics of Agreste over the 1994-2010 period at 45 cropland and 48 grassland départements, for a range of rooting depths. The number of départements where the simulated annual maximum Bag presents a significant correlation with the yield observations is used as a metric to benchmark the root water uptake models. Significant correlations (p value neutral impact of the most refined versions of the model is found with respect to the simplified soil hydrology scheme. This shows that efforts should be made in future studies to reduce other sources of uncertainty, e.g. by using a more detailed soil and root density profile description together with satellite vegetation products. It is found that modelling additional subroot-zone base flow soil layers does not improve (and may even degrade) the representation of the inter-annual variability of the vegetation above-ground biomass. These results are

  10. A biophysical approach using water deficit factor for daily estimations of evapotranspiration and CO2 uptake in Mediterranean environments

    Science.gov (United States)

    Helman, David; Lensky, Itamar M.; Osem, Yagil; Rohatyn, Shani; Rotenberg, Eyal; Yakir, Dan

    2017-09-01

    Estimations of ecosystem-level evapotranspiration (ET) and CO2 uptake in water-limited environments are scarce and scaling up ground-level measurements is not straightforward. A biophysical approach using remote sensing (RS) and meteorological data (RS-Met) is adjusted to extreme high-energy water-limited Mediterranean ecosystems that suffer from continuous stress conditions to provide daily estimations of ET and CO2 uptake (measured as gross primary production, GPP) at a spatial resolution of 250 m. The RS-Met was adjusted using a seasonal water deficit factor (fWD) based on daily rainfall, temperature and radiation data. We validated our adjusted RS-Met with eddy covariance flux measurements using a newly developed mobile lab system and the single active FLUXNET station operating in this region (Yatir pine forest station) at a total of seven forest and non-forest sites across a climatic transect in Israel (280-770 mm yr-1). RS-Met was also compared to the satellite-borne MODIS-based ET and GPP products (MOD16 and MOD17, respectively) at these sites.Results show that the inclusion of the fWD significantly improved the model, with R = 0.64-0.91 for the ET-adjusted model (compared to 0.05-0.80 for the unadjusted model) and R = 0.72-0.92 for the adjusted GPP model (compared to R = 0.56-0.90 of the non-adjusted model). The RS-Met (with the fWD) successfully tracked observed changes in ET and GPP between dry and wet seasons across the sites. ET and GPP estimates from the adjusted RS-Met also agreed well with eddy covariance estimates on an annual timescale at the FLUXNET station of Yatir (266 ± 61 vs. 257 ± 58 mm yr-1 and 765 ± 112 vs. 748 ± 124 gC m-2 yr-1 for ET and GPP, respectively). Comparison with MODIS products showed consistently lower estimates from the MODIS-based models, particularly at the forest sites. Using the adjusted RS-Met, we show that afforestation significantly increased the water use efficiency (the ratio of carbon uptake to ET) in this region

  11. 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

  12. Predicting Phenologic Response to Water Stress and Implications for Carbon Uptake across the Southeast U.S.

    Science.gov (United States)

    Lowman, L.; Barros, A. P.

    2016-12-01

    Representation of plant photosynthesis in modeling studies requires phenologic indicators to scale carbon assimilation by plants. These indicators are typically the fraction of photosynthetically active radiation (FPAR) and leaf area index (LAI) which represent plant responses to light and water availability, as well as temperature constraints. In this study, a prognostic phenology model based on the growing season index is adapted to determine the phenologic indicators of LAI and FPAR at the sub-daily scale based on meteorological and soil conditions. Specifically, we directly model vegetation green-up and die-off responses to temperature, vapor pressure deficit, soil water potential, and incoming solar radiation. The indices are based on the properties of individual plant functional types, driven by observational data and prior modeling applications. First, we describe and test the sensitivity of the carbon uptake response to predicted phenology for different vegetation types. Second, the prognostic phenology model is incorporated into a land-surface hydrology model, the Duke Coupled Hydrology Model with Prognostic Vegetation (DCHM-PV), to demonstrate the impact of dynamic phenology on modeled carbon assimilation rates and hydrologic feedbacks. Preliminary results show reduced carbon uptake rates when incorporating a prognostic phenology model that match well against the eddy-covariance flux tower observations. Additionally, grassland vegetation shows the most variability in LAI and FPAR tied to meteorological and soil conditions. These results highlight the need to incorporate vegetation-specific responses to water limitation in order to accurately estimate the terrestrial carbon storage component of the global carbon budget.

  13. Uptake of barium and strontium by cress (Lepidium sativum) in water culture and the presence of an inhibiting soluble factor

    International Nuclear Information System (INIS)

    Oestling, O.; Kopp, P.; Burkart, W.

    1991-01-01

    Seeds of cress were sown in various densities on plastic grids placed in half-litre dishes filled with either a dilute salt solution or distilled water. After 2 days the radionuclides 133 Ba, 134 Cs and 85 Sr were added, and after another 5 days the plants were harvested and the radioactivity measured by γ-ray spectrometry. Plants in alternated sparse cultures concentrated less radioactivity of Ba and Sr than the corresponding non-alternated cultures. Furthermore, when water from very dense cultures on which plants had grown for a week was sterile-filtered and added to fresh cultures, it was shown that this conditioned water strongly inhibited the uptake of Ba and Sr. The difference in radionuclide concentration in the plants as a function of plant density disappeared when the concentrations of Ca and Mg in the nutrient solution were raised to 0.15 and 0.40 mM, respectively. Apparently a chelating substance, possibly excreted from the plant roots, is responsible for the inhibition of the uptake of bivalent cations, and this agent becomes saturated when bivalent cations are present at sufficiently high concentrations. (author)

  14. EFFECT OF IMMERSION TEMPERATURE ON THE WATER UPTAKE OF POLYPROPYLENE/WOOD FLOUR/ORGANOCLAY HYBRID NANOCOMPOSITE

    Directory of Open Access Journals (Sweden)

    Behzad Kord

    2011-02-01

    Full Text Available Polypropylene/wood flour/organoclay hybrid nanocomposites were melt-compounded in an internal mixer at 190 oC and 60 rpm rotor speed. Then samples were fabricated by injection molding. Effects of immersion temperature on the water uptake of hybrid nanocomposite were investigated. To meet this objective, water absorption of samples was determined after 24 h immersion in distilled water at different temperatures (25, 50, 75, and 100 °C. Results indicated that immersion temperature had a significant influence on the water absorption of composites. By increasing the temperature, water absorption increases as well. The maximum water absorption of composite is decreased by increasing the nanoclay and compatibilizer content. The morphology of nanoclay was determined by X-ray diffraction (XRD and transmission electron microscopy. The effect of morphology on water absorption was also evaluated. Due to inadequate compatibilizer, exfoliated morphology of nanoclay was not obtained, but there was evidence of intercalation. The order of intercalation for samples containing 3 phc was higher than that of 6 phc at the same PP-g-MA content due to some agglomerations of organoclay.

  15. Uptake of uranium by aquatic plants growing in fresh water ecosystem around uranium mill tailings pond at Jaduguda, India

    Energy Technology Data Exchange (ETDEWEB)

    Jha, V.N., E-mail: jhavn1971@gmail.com; Tripathi, R.M., E-mail: tripathirm@yahoo.com; Sethy, N.K., E-mail: sethybarc@rediffmail.com; Sahoo, S.K., E-mail: sksbarc@gmail.com

    2016-01-01

    Concentration of uranium was determined in aquatic plants and substrate (sediment or water) of fresh water ecosystem on and around uranium mill tailings pond at Jaduguda, India. Aquatic plant/substrate concentration ratios (CRs) of uranium were estimated for different sites on and around the uranium mill tailings disposal area. These sites include upstream and downstream side of surface water sources carrying the treated tailings effluent, a small pond inside tailings disposal area and residual water of this area. Three types of plant groups were investigated namely algae (filamentous and non-filamentous), other free floating & water submerged and sediment rooted plants. Wide variability in concentration ratio was observed for different groups of plants studied. The filamentous algae uranium concentration was significantly correlated with that of water (r = 0.86, p < 0.003). For sediment rooted plants significant correlation was found between uranium concentration in plant and the substrate (r = 0.88, p < 0.001). Both for other free floating species and sediment rooted plants, uranium concentration was significantly correlated with Mn, Fe, and Ni concentration of plants (p < 0.01). Filamentous algae, Jussiaea and Pistia owing to their high bioproductivity, biomass, uranium accumulation and concentration ratio can be useful for prospecting phytoremediation of stream carrying treated or untreated uranium mill tailings effluent. - Highlights: • Uranium mill tailings pond. • Jaduguda, India. • Fresh water plants. • Uranium uptake. • Relationship of uranium with stable elements.

  16. Water uptake in free films and coatings using the Brasher and Kingsbury equation: a possible explanation of the different values obtained by electrochemical Impedance spectroscopy and gravimetry

    International Nuclear Information System (INIS)

    Vosgien Lacombre, C.; Bouvet, G.; Trinh, D.; Mallarino, S.; Touzain, S.

    2017-01-01

    For many years, the water uptake in organic coatings was measured by EIS and/or gravimetry but differences in water content values were found in almost all studies. The Brasher-Kingsbury equation used in the electrochemical analysis (EIS) is often criticized because elementary assumptions may be unvalid. The origin of the discrepancy between both methods is still of interest because many questions remain open and this study aims to provide new insights to these questions. In this work, free films and coatings of a model epoxy-amine system were immersed in a 3 wt.% NaCl solution. The water uptake in free films was evaluated using gravimetric measurements and EIS, using the Basher-Kingsbury equation. The mass of free-films used in the EIS tests was measured and compare to gravimetric measurements while the water uptake (EIS) in free films was compared to that obtained with coatings. It was found that the mass increase of free films tested with EIS was in agreement with gravimetric measurements but was always lower than the water uptake obtained by EIS. Moreover, the water uptake in free films (EIS) was different from that obtained with coatings. In all cases, it was found that the Basher-Kingsbury equation overestimated the water uptake. It appears that the differences between EIS and gravimetric measurements can be analyzed in terms of geometrical effects. Indeed, the swelling in free films and coatings can be monitored by DMA and SECM during ageing. Finally, by mixing the experimental swelling data and the Brasher-Kingsbury equation, the same value of water uptake was obtained by EIS and gravimetry for coatings.

  17. How to put plant root uptake into a soil water flow model [version 1; referees: 2 approved, 1 approved with reservations

    Directory of Open Access Journals (Sweden)

    Xuejun Dong

    2016-01-01

    Full Text Available The need for improved crop water use efficiency calls for flexible modeling platforms to implement new ideas in plant root uptake and its regulation mechanisms. This paper documents the details of modifying a soil infiltration and redistribution model to include (a dynamic root growth, (b non-uniform root distribution and water uptake, (c the effect of water stress on plant water uptake, and (d soil evaporation. The paper also demonstrates strategies of using the modified model to simulate soil water dynamics and plant transpiration considering different sensitivity of plants to soil dryness and different mechanisms of root water uptake. In particular, the flexibility of simulating various degrees of compensated uptake (whereby plants tend to maintain potential transpiration under mild water stress is emphasized. The paper also describes how to estimate unknown root distribution and rooting depth parameters by the use of a simulation-based searching method. The full documentation of the computer code will allow further applications and new development.

  18. The effects of isoprene and NOx on secondary organic aerosols formed through reversible and irreversible uptake to aerosol water

    Science.gov (United States)

    El-Sayed, Marwa M. H.; Ortiz-Montalvo, Diana L.; Hennigan, Christopher J.

    2018-01-01

    Isoprene oxidation produces water-soluble organic gases capable of partitioning to aerosol liquid water. The formation of secondary organic aerosols through such aqueous pathways (aqSOA) can take place either reversibly or irreversibly; however, the split between these fractions in the atmosphere is highly uncertain. The aim of this study was to characterize the reversibility of aqSOA formed from isoprene at a location in the eastern United States under substantial influence from both anthropogenic and biogenic emissions. The reversible and irreversible uptake of water-soluble organic gases to aerosol water was characterized in Baltimore, Maryland, USA, using measurements of particulate water-soluble organic carbon (WSOCp) in alternating dry and ambient configurations. WSOCp evaporation with drying was observed systematically throughout the late spring and summer, indicating reversible aqSOA formation during these times. We show through time lag analyses that WSOCp concentrations, including the WSOCp that evaporates with drying, peak 6 to 11 h after isoprene concentrations, with maxima at a time lag of 9 h. The absolute reversible aqSOA concentrations, as well as the relative amount of reversible aqSOA, increased with decreasing NOx / isoprene ratios, suggesting that isoprene epoxydiol (IEPOX) or other low-NOx oxidation products may be responsible for these effects. The observed relationships with NOx and isoprene suggest that this process occurs widely in the atmosphere, and is likely more important in other locations characterized by higher isoprene and/or lower NOx levels. This work underscores the importance of accounting for both reversible and irreversible uptake of isoprene oxidation products to aqueous particles.

  19. Does water chemistry affect the dietary uptake and toxicity of silver nanoparticles by the freshwater snail Lymnaea stagnalis?

    Science.gov (United States)

    López-Serrano Oliver, Ana; Croteau, Marie-Noële; Stoiber, Tasha L.; Tejamaya, Mila; Römer, Isabella; Lead, Jamie R.; Luoma, Samuel N.

    2014-01-01

    Silver nanoparticles (AgNPs) are widely used in many applications and likely released into the aquatic environment. There is increasing evidence that Ag is efficiently delivered to aquatic organisms from AgNPs after aqueous and dietary exposures. Accumulation of AgNPs through the diet can damage digestion and adversely affect growth. It is well recognized that aspects of water quality, such as hardness, affect the bioavailability and toxicity of waterborne Ag. However, the influence of water chemistry on the bioavailability and toxicity of dietborne AgNPs to aquatic invertebrates is largely unknown. Here we characterize for the first time the effects of water hardness and humic acids on the bioaccumulation and toxicity of AgNPs coated with polyvinyl pyrrolidone (PVP) to the freshwater snail Lymnaea stagnalis after dietary exposures. Our results indicate that bioaccumulation and toxicity of Ag from PVP-AgNPs ingested with food are not affected by water hardness and by humic acids, although both could affect interactions with the biological membrane and trigger nanoparticle transformations. Snails efficiently assimilated Ag from the PVP-AgNPs mixed with diatoms (Ag assimilation efficiencies ranged from 82 to 93%). Rate constants of Ag uptake from food were similar across the entire range of water hardness and humic acid concentrations. These results suggest that correcting regulations for water quality could be irrelevant and ineffective where dietary exposure is important.

  20. Effects of different mycorrhiza species on grain yield, nutrient uptake and oil content of sunflower under water stress

    Directory of Open Access Journals (Sweden)

    Mostafa Heidari

    2014-01-01

    Full Text Available The role of arbuscular mycorrhizal fungi in alleviating water stress is well documented. In order to study the effects of water stress and two different mycorrhiza species on grain yield, nutrient uptake and oil content of sunflower, a field experiment as split plot design with three replications was conducted in the Research Field Station, Zabol University, Zabol, Iran in 2011. Water stress treatments included control as 90% of field capacity (W1, 70% field capacity (W2 and 50% field capacity (W3 assigned to the main plots and two different mycorrhiza species, consisting of M1 = control (without any inoculation, M2 = Glumus mossea and M3 = Glumus etanicatum as sub plots. Results showed that by increasing water stress from control (W1 to W3 treatment, grain yield was significantly decreased. The reduction in the level of W3 was 15.05%. The content of potassium in seeds significantly decreased due to water stress but water stress upto W2 treatment increased the content of phosphorus, nitrogen and oil content of seeds. In between two species of mycorrhiza in sunflower plants, Glumus etanicatum had the highest effect on grain yield and these elements in seeds and increased both.

  1. Investigating uptake of water-dispersible CdSe/ZnS quantum dot nanoparticles by Arabidopsis thaliana plants

    International Nuclear Information System (INIS)

    Navarro, Divina A.; Bisson, Mary A.; Aga, Diana S.

    2012-01-01

    Graphical abstract: This study highlights the importance of quantum dot (QD) structural stability in preventing phytotoxicity. Overall, there is no evidence that Arabidopsis thaliana plants can internalize intact QDs within 1–7 days of exposure, with or without humic acids. Highlights: ► Potential uptake of water-dispersible CdSe/ZnS QDs by Arabidopsis was demonstrated. ► QDs were not internalized by Arabidopsis as intact particles. ► Plants exposed to Cd-, Se-, and QD + HA suspensions experienced oxidative stress. ► An effective LC–MS method proves detection of low levels of glutathione in plants. ► Uptake of Cd and/or Se leached from QDs is of major concern. - Abstract: Interest on the environmental impacts of engineered nanomaterials has rapidly increased over the past years because it is expected that these materials will eventually be released into the environment. The present work investigates the potential root uptake of water-dispersible CdSe/ZnS quantum dots (QDs) by the model plant species, Arabidopsis thaliana. Experiments revealed that Arabidopsis exposed to QDs that are dispersed in Hoagland's solution for 1–7 days did not internalize intact QDs. Analysis of Cd and Se concentrations in roots and leaves by inductively-coupled plasma mass spectrometry indicated that Cd and Se from QD-treated plants were not translocated into the leaves, and remained in the root system of Arabidopsis. Furthermore, fluorescence microscopy showed strong evidence that the QDs were generally on the outside surfaces of the roots, where the amount of QDs adsorbed is dependent on the stability of the QDs in suspension. Despite no evidence of nanoparticle internalization, the ratio of reduced glutathione levels (GSH) relative to the oxidized glutathione (GSSG) in plants decreased when plants were exposed to QD dispersions containing humic acids, suggesting that QDs caused oxidative stress on the plant at this condition.

  2. Aflatoxins and fumonisin contamination of marketed maize, maize ...

    African Journals Online (AJOL)

    Aflatoxins and fumonisin contamination of marketed maize, maize bran and maize used as animal feed in northern ... PROMOTING ACCESS TO AFRICAN RESEARCH ... African Journal of Food, Agriculture, Nutrition and Development.

  3. Vanadium uptake and an effect of vanadium treatment on 18F-labeled water movement in a cowpea plant by positron emitting tracer imaging system (PETIS)

    International Nuclear Information System (INIS)

    Furukawa, J.; Yokota, H.; Tanoi, K.; Ueoka, S.; Nakanishi, T.M.; Uchida, H.; Tsuji, A.

    2001-01-01

    Real time vanadate (V 5+ ) uptake imaging in a cowpea plant by positron emitting tracer imaging system (PETIS) is presented. Vanadium-48 was produced by bombarding a Sc foil target with 50 MeV α-particles at Takasaki Ion Accelerators for Advanced Radiation application (TIARA) AVF cyclotron. Then 48 V was added to the culture solution to investigate the V distribution in a cowpea plant. The real time uptake of the 48 V was monitored by PETIS. Distribution of 48 V in a whole plant was measured after 3, 6 and 20 hours of V treatment by Bio-imaging Analyzer System (BAS). After the 20 hour treatment, vanadate was detected at the up-ground part of the plant. To know the effect of V uptake on plant activity, 18 F-labeled water uptake was analyzed by PETIS. When a cowpea plant was treated with V for 20 hours before 18 F-labeled water uptake experiment, the total amount of 18 F-labeled water absorption ws drastically decreased. Results suggest the inhibition of water uptake was mainly caused by the vanadate already moved to the up-ground part of the plant. (author)

  4. Sulfonated poly(fluorenyl ether ketone nitrile) electrolyte membrane with high proton conductivity and low water uptake

    Energy Technology Data Exchange (ETDEWEB)

    Tian, S.H.; Wang, S.J.; Xiao, M.; Meng, Y.Z. [State Key Laboratory of Optoelectronic Materials and Technologies/Institute of Optoelectronic and Functional Composite Materials, Sun Yat-sen University, Guangzhou 510275 (China); Shu, D. [School of Chemistry and Environmental, South China Normal University, Guangzhou 510006 (China)

    2010-01-01

    High molecular weight sulfonated poly(fluorenyl ether ketone nitrile)s with different equivalent weight (EW) from 681 to 369 g mequiv.{sup -1} are synthesized by the nucleophilic substitution polycondensation of various amounts of sulfonated difluorobenzophenone (SDFBP) and 2,6-difluorobenzonitrile (DFBN) with bisphenol fluorene (BPF). The synthesized copolymers are characterized by {sup 1}H NMR, FT-IR, TGA, and DSC techniques. The membranes cast from the corresponding copolymers exhibit superior thermal stability, good oxidative stability and high proton conductivity, but low water uptake due to the strong nitrile dipole interchain interactions that combine to limit swelling. Among all the membranes, the membrane with EW of 441 g mequiv.{sup -1} shows optimum properties of both high proton conductivity of 41.9 mS cm{sup -1} and low water uptake of 42.6%. Accordingly, That membrane is fabricated into a membrane electrode assembly (MEA) and evaluated in a single proton exchange membrane fuel cell (PEMFC). The experimental results indicate its similar cell performance as that of Nafion {sup registered} 117 at 70 C, but much better cell performance at higher temperatures. At the potential of 0.6 V, the current density of fuel cell using the prepared membrane and Nafion {sup registered} 117 is 0.46 and 0.25 A cm{sup -2}, respectively. The highest current density of the former reaches as high as 1.25 A cm{sup -2}. (author)

  5. Growth of Phragmites australis (Cav.) Trin ex. Steudel in mine water treatment wetlands: effects of metal and nutrient uptake

    International Nuclear Information System (INIS)

    Batty, Lesley C.; Younger, Paul L.

    2004-01-01

    The abandoned mine of Shilbottle Colliery, Northumberland, UK is an example of acidic spoil heap discharge that contains elevated levels of many metals. Aerobic wetlands planted with the common reed, Phragmites australis, were constructed at the site to treat surface runoff from the spoil heap. The presence of a perched water table within the spoil heap resulted in the lower wetlands receiving acidic metal contaminated water from within the spoil heap while the upper wetland receives alkaline, uncontaminated surface runoff from the revegetated spoil. This unique situation enabled the comparison of metal uptake and growth of plants used in treatment schemes in two cognate wetlands. Results indicated a significant difference in plant growth between the two wetlands in terms of shoot height and seed production. Analyses of metal and nutrient concentrations within plant tissues provided the basis for three hypotheses to explain these differences: (i) the toxic effects of high levels of metals in shoot tissues (ii) the inhibition of Ca (an essential nutrient) uptake by the presence of metals and H + ions, and (iii) low concentrations of bioavailable nitrogen sources resulting in nitrogen deficiency. This has important implications for the engineering of constructed wetlands in terms of the potential success of plant establishment and vegetation development

  6. Foliar antitranspirant and soil superabsorbent hydrogel affects photosynthetic gas exchange and water use efficiency of maize grown under low rainfall conditions.

    Science.gov (United States)

    Yang, Wei; Guo, Shi-Wen; Li, Pin-Fang; Song, Ri-Quan; Yu, Jian

    2018-06-08

    Two lysimeter experiments with maize plants were conducted to inquiry the effect of combined superabsorbent polymer (SAP) and fulvic acid (FA) application on photosynthetic gas exchange and water use efficiency (WUE) under deficit irrigation conditions. Soil SAP (45 kg ha -1 ) was applied while sowing, and FA solution (2 g L -1 ) was sprayed onto crop canopy three times at later plant growth periods. Combining SAP and FA application significantly improved plant photosynthesis, chlorophyll contents, and instantaneous WUE, while maintaining the optimal leaf stomatal transpiration. The effect of combined two chemicals use on photosynthesis and leaf instantaneous WUE was superior compared with the effects of their individual applications. As compared with plots not treated with chemicals, soil SAP significantly improved the yield by 12% and grain WUE by 10% when averaged across the two experiments, whereas foliar FA application did not affect yield and grain WUE. In contrast, the combined use of two chemicals significantly increased the yield by 20% and grain WUE by 26%, largely attributed to the increase in grain number. Soil SAP and foliar FA use, under low rainfall conditions, had little influence on crop water consumption but improved plant WUE by enhancing photosynthesis and increasing kernel number. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  7. The cis-regulatory element CCACGTGG is involved in ABA and water-stress responses of the maize gene rab28.

    Science.gov (United States)

    Pla, M; Vilardell, J; Guiltinan, M J; Marcotte, W R; Niogret, M F; Quatrano, R S; Pagès, M

    1993-01-01

    The maize gene rab28 has been identified as ABA-inducible in embryos and vegetative tissues. It is also induced by water stress in young leaves. The proximal promoter region contains the conserved cis-acting element CCACGTGG (ABRE) reported for ABA induction in other plant genes. Transient expression assays in rice protoplasts indicate that a 134 bp fragment (-194 to -60 containing the ABRE) fused to a truncated cauliflower mosaic virus promoter (35S) is sufficient to confer ABA-responsiveness upon the GUS reporter gene. Gel retardation experiments indicate that nuclear proteins from tissues in which the rab28 gene is expressed can interact specifically with this 134 bp DNA fragment. Nuclear protein extracts from embryo and water-stressed leaves generate specific complexes of different electrophoretic mobility which are stable in the presence of detergent and high salt. However, by DMS footprinting the same guanine-specific contacts with the ABRE in both the embryo and leaf binding activities were detected. These results indicate that the rab28 promoter sequence CCACGTGG is a functional ABA-responsive element, and suggest that distinct regulatory factors with apparent similar affinity for the ABRE sequence may be involved in the hormone action during embryo development and in vegetative tissues subjected to osmotic stress.

  8. 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

  9. Vascular aspects of water uptake mechanisms in the toad skin: perfusion, diffusion, confusion

    DEFF Research Database (Denmark)

    Willumsen, Niels; Viborg, Arne L; Hillyard, Stanley D

    2007-01-01

    Blood cell flow (BCF) in the water absorbing "seat patch" region of toad skin was measured with laser Doppler flow cytometry. BCF of dehydrated toads increased by a factor of 6-8 when water contact was made and declined gradually as toads rehydrated. Water absorption was initially stimulated...... and declined in parallel with BCF. Water absorption measured during the initial rehydration period did not correlate with BCF and hydrated toads injected with AVT increased water absorption without an increase in BCF indicating the lack of an obligate relation between blood flow and water absorption....... Aquaporins 1-3 were characterized by RT-PCR analysis of seat patch skin. AQP 1 was localized in the endothelium of subepidermal capillaries and serves as a pathway for water absorption in series with the apical and basolateral membranes of the epithelium. Dehydrated toads rehydrated more rapidly from dilute...

  10. Seasonal changes in depth of water uptake for encroaching trees Juniperus virginiana and Pinus ponderosa and two dominant C4 grasses in a semiarid grassland.

    Science.gov (United States)

    Eggemeyer, Kathleen D; Awada, Tala; Harvey, F Edwin; Wedin, David A; Zhou, Xinhua; Zanner, C William

    2009-02-01

    We used the natural abundance of stable isotopic ratios of hydrogen and oxygen in soil (0.05-3 m depth), plant xylem and precipitation to determine the seasonal changes in sources of soil water uptake by two native encroaching woody species (Pinus ponderosa P. & C. Lawson, Juniperus virginiana L.), and two C(4) grasses (Schizachyrium scoparium (Michx.) Nash, Panicum virgatum L.), in the semiarid Sandhills grasslands of Nebraska. Grass species extracted most of their water from the upper soil profile (0.05-0.5 m). Soil water uptake from below 0.5 m depth increased under drought, but appeared to be minimal in relation to the total water use of these species. The grasses senesced in late August in response to drought conditions. In contrast to grasses, P. ponderosa and J. virginiana trees exhibited significant plasticity in sources of water uptake. In winter, tree species extracted a large fraction of their soil water from below 0.9 m depth. In spring when shallow soil water was available, tree species used water from the upper soil profile (0.05-0.5 m) and relied little on water from below 0.5 m depth. During the growing season (May-August) significant differences between the patterns of tree species water uptake emerged. Pinus ponderosa acquired a large fraction of its water from the 0.05-0.5 and 0.5-0.9 m soil profiles. Compared with P. ponderosa, J. virginiana acquired water from the 0.05-0.5 m profile during the early growing season but the amount extracted from this profile progressively declined between May and August and was mirrored by a progressive increase in the fraction taken up from 0.5-0.9 m depth, showing plasticity in tracking the general increase in soil water content within the 0.5-0.9 m profile, and being less responsive to growing season precipitation events. In September, soil water content declined to its minimum, and both tree species shifted soil water uptake to below 0.9 m. Tree transpiration rates (E) and water potentials (Psi) indicated

  11. The relative importance of water and diet for uptake and subcellular distribution of cadmium in the deposit-feeding polychaete, Capitella sp I

    DEFF Research Database (Denmark)

    Selck, Henriette; Forbes, Valery E.

    2004-01-01

    The impact of dietary and water exposure on the accumulation and distribution of cadmium (Cd) in subcellular components of the polychaete Capitella sp. I was investigated. Worms were exposed to either dissolved Cd alone ('Water-Only' treatments; WO) or diet-bound Cd alone ('Algae-bound Only......, starvation likewise influenced the distribution of protein between mitochondria and cytosol. Cutaneous uptake and accumulation of Cd from the water was related to surface area while dietary uptake was influenced by the amount of sediment passing through the gut. Irrespective of exposure route, Cd...

  12. Sugar transport by maize endosperm suspension cultures

    International Nuclear Information System (INIS)

    Felker, F.C.; Goodwin, J.C.

    1987-01-01

    To determine the mechanism of sugar uptake by suspension cultures derived from developing maize (Zea mays L.) endosperm, incorporation of radioactivity from 14 C-sugars by the tissue in the mid-log phase of growth was examined. Among the sugars tested was l'-deoxy-l'-fluorosucrose (FS), a derivative not hydrolyzed by invertase but recognized by sucrose carriers in other systems. At 40 mM, uptake of label from FS was 23% of that from sucrose, while uptake of label from L-glucose (used as a control for medium carry-over and adsorption) was 16% of that from sucrose. Uptake of label from sucrose did not increase at concentrations above 50 mM, possibly due to a rate-limiting requirement for extracellular hydrolysis. Kinetic analysis revealed both saturable and linear components of uptake for glucose and fructose. The rate of fructose uptake exceeded that of glucose at all concentrations. Fructose uptake at 20 mM was inhibited by NaN 3 , HgCl 2 , dinitrophenol, carbonyl cyanide m-chlorophenylhydrazone, and p-chloromercuribenzenesulfonic acid. Results suggest that sucrose is hydrolyzed prior to uptake, and that fructose is transported preferentially by a carrier sensitive to an external sulfhydryl group inhibitor. Metabolic activity is required for sugar uptake. The specificity of the hexose transporter is currently being investigated

  13. Circadian rhythm in ''1''5O-labeled water uptake manner of a soybean plant by PETIS (Positron Emitting Tracer Imaging System)

    International Nuclear Information System (INIS)

    Nakanishi, Tomoko M.; Yokota, Harumi; Tanoi, Keitaro; Furukawa, Jun; Ikeue, Natsuko; Ookuni, Yoko; Uchida, Hiroshi; Tsuji, Atsunori

    2001-01-01

    We present a circadian rhythm of water uptake manner in a soybean plant through realtime imaging of water, labeled with 15 O. Nitrogen gas was irradiated with deuterons accelerated by a cyclotron at Hamamatsu Photonics Co. to produce 15 O-labeled water. Then the 15 O-labeled water was supplied to a soybean plant from the root and the realtime water uptake amount was measured for 20 min by Positron Emitting Tracer Imaging System (PETIS). All the targeting positions for the measurements were stems, two points at an internode between root and the first leaves, between the first leaves and the first trifoliates and between the first trifoliates and the second trifoliates. The water uptake amount was gradually increased and showed its maximum at around 13:00, especially at the basal part of the stem. Then the water uptake activity was gradually decreased until 17:00. The water amount taken up by a plant at 13:00 was about 40% higher than that at 17:00. (author)

  14. Circadian rhythm in ''1''5O-labeled water uptake manner of a soybean plant by PETIS (Positron Emitting Tracer Imaging System)

    Energy Technology Data Exchange (ETDEWEB)

    Nakanishi, Tomoko M.; Yokota, Harumi; Tanoi, Keitaro; Furukawa, Jun; Ikeue, Natsuko; Ookuni, Yoko [Tokyo Univ. (Japan). Graduate School of Agricultural and Life Sciences; Uchida, Hiroshi; Tsuji, Atsunori

    2001-05-01

    We present a circadian rhythm of water uptake manner in a soybean plant through realtime imaging of water, labeled with {sup 15}O. Nitrogen gas was irradiated with deuterons accelerated by a cyclotron at Hamamatsu Photonics Co. to produce {sup 15}O-labeled water. Then the {sup 15}O-labeled water was supplied to a soybean plant from the root and the realtime water uptake amount was measured for 20 min by Positron Emitting Tracer Imaging System (PETIS). All the targeting positions for the measurements were stems, two points at an internode between root and the first leaves, between the first leaves and the first trifoliates and between the first trifoliates and the second trifoliates. The water uptake amount was gradually increased and showed its maximum at around 13:00, especially at the basal part of the stem. Then the water uptake activity was gradually decreased until 17:00. The water amount taken up by a plant at 13:00 was about 40% higher than that at 17:00. (author)

  15. Analysis of virtual water flows associated with the trade of maize in the SADC region: importance of scale

    CSIR Research Space (South Africa)

    Dabrowski, James M

    2009-10-01

    Full Text Available The concept of virtual water encourages a country to view agricultural crops in terms of the amount of water required to produce those crops, with a view to implementing trading policies that promote the saving of scarce water resources. Recently...

  16. Estimate of uptake and translocation of emerging organic contaminants from irrigation water concentration in lettuce grown under controlled conditions.

    Science.gov (United States)

    Hurtado, Carlos; Domínguez, Carmen; Pérez-Babace, Lorea; Cañameras, Núria; Comas, Jordi; Bayona, Josep M

    2016-03-15

    The widespread distribution of emerging organic contaminants (EOCs) in the water cycle can lead to their incorporation in irrigated crops, posing a potential risk for human consumption. To gain further insight into the processes controlling the uptake of organic microcontaminants, Batavia lettuce (Lactuca sativa) grown under controlled conditions was watered with EOCs (e.g., non-steroidal anti-inflammatories, sulfonamides, β-blockers, phenolic estrogens, anticonvulsants, stimulants, polycyclic musks, biocides) at different concentrations (0-40μgL(-1)). Linear correlations were obtained between the EOC concentrations in the roots and leaves and the watering concentrations for most of the contaminants investigated. However, large differences were found in the root concentration factors ( [Formula: see text] =0.27-733) and leaf translocation concentration factors ( [Formula: see text] =0-3) depending on the persistence of the target contaminants in the rhizosphere and the specific physicochemical properties of each one. With the obtained dataset, a simple predictive model based on a linear regression and the root bioconcentration and translocation factors can be used to estimate the concentration of the target EOCs in leaves based on the dose supplied in the irrigation water or the soil concentration. Finally, enantiomeric fractionation of racemic ibuprofen from the initial spiking mixture suggests that biodegradation mainly occurs in the rhizosphere. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Oxygen uptake in water polo, comparison and agreement in cycle ergometer and eggbeater kick: A pilot study

    Directory of Open Access Journals (Sweden)

    Ligia Ignêz Engelmann

    Full Text Available Abstract The aim of this study was to compare and verify the agreement of maximal oxygen uptake (VO2 max values obtained from tests on land and in water. Twelve recreational water polo players (30.5 ± 7.7 years; 79.2 ± 7.2 kg body mass; 179.1 ± 5.9 cm height were assessed in two phases: (1 in laboratory with maximal test on a cycle ergometer and (2 in a swimming pool with maximal test in eggbeater kick. Maximum values obtained in the two tests (respectively, cycle ergometer, and eggbeater kick: VO2 max = 40.2 ± 2.7 ml.kg-1.min-1 and 38.4 ± 5.7 ml.kg-1.min-1; RER = 1.17 ± 0.08 and 1.19 ± 0.12; HR max = 181.4 ± 11.7 bpm and 179 ± 11.7 bpm; IEP = 20 and 20 did not show significant differences. According to the Bland-Altman analyses, there were acceptable limits of agreement between the two tests (land and water. Therefore, it can be concluded that the eggbeater kick test is a specific and valid protocol to asses VO2 max in water polo players.

  18. Studies on different concentration of lead (Pb and sewage water on Pb uptake and growth of Radish (Raphanus sativus

    Directory of Open Access Journals (Sweden)

    Qudratullah Khan

    2014-04-01

    Full Text Available To investigate the accumulation of lead (Pb by radish (Raphanus sativus cultivars a study was carried out at Department of Soil and Environmental Sciences, Gomal University, Dera Ismail Khan (Pakistan, during 2012. Two radish varieties i.e., exotic and local, were used. The treatments included sewage water and different concentrations of Pb @ 25, 100, 200 and 400 mg L-1. The results showed that the total biomass of both the radish varieties were nonsignificantly influenced by the applied Pb concentrations and sewage water, except for root diameter which were significantly greater in the local cultivar (3.261 cm.Pb treatments significantly reduced the growth and yield of both the cultivars. While the Pb uptake by the root and leaf of radish plants was increased by the increasing the applied Pb levels, with the highest value for root (19.008 mg kg-1 and leaf (16.134 mg kg-1 in the treatment receiving the highest applied Pb concentrations. The total biomass, fresh weight of root and root diameter was found significantly higher except for Pb @ 400 mg L-1, in the plants receiving sewage water as compared to the control and different levels of Pb. The interaction amongst the varieties and treatments were found significantly different for various parameters. Thus, it can be concluded, that the use of sewage water and Pb contaminated wastewater results in higher metal concentration in the radish root and may lead to different types of health problems to consumers.

  19. A biophysical approach using water deficit factor for daily estimations of evapotranspiration and CO2 uptake in Mediterranean environments

    Directory of Open Access Journals (Sweden)

    D. Helman

    2017-09-01

    Full Text Available Estimations of ecosystem-level evapotranspiration (ET and CO2 uptake in water-limited environments are scarce and scaling up ground-level measurements is not straightforward. A biophysical approach using remote sensing (RS and meteorological data (RS–Met is adjusted to extreme high-energy water-limited Mediterranean ecosystems that suffer from continuous stress conditions to provide daily estimations of ET and CO2 uptake (measured as gross primary production, GPP at a spatial resolution of 250 m. The RS–Met was adjusted using a seasonal water deficit factor (fWD based on daily rainfall, temperature and radiation data. We validated our adjusted RS–Met with eddy covariance flux measurements using a newly developed mobile lab system and the single active FLUXNET station operating in this region (Yatir pine forest station at a total of seven forest and non-forest sites across a climatic transect in Israel (280–770 mm yr−1. RS–Met was also compared to the satellite-borne MODIS-based ET and GPP products (MOD16 and MOD17, respectively at these sites.Results show that the inclusion of the fWD significantly improved the model, with R =  0.64–0.91 for the ET-adjusted model (compared to 0.05–0.80 for the unadjusted model and R =  0.72–0.92 for the adjusted GPP model (compared to R =  0.56–0.90 of the non-adjusted model. The RS–Met (with the fWD successfully tracked observed changes in ET and GPP between dry and wet seasons across the sites. ET and GPP estimates from the adjusted RS–Met also agreed well with eddy covariance estimates on an annual timescale at the FLUXNET station of Yatir (266 ± 61 vs. 257 ± 58 mm yr−1 and 765 ± 112 vs. 748 ± 124 gC m−2 yr−1 for ET and GPP, respectively. Comparison with MODIS products showed consistently lower estimates from the MODIS-based models, particularly at the forest sites. Using the adjusted RS–Met, we show that afforestation

  20. Effects of water inflow and early water uptake on buffer and backfill materials in a KBS-3V repository

    International Nuclear Information System (INIS)

    Boergesson, L.; Sanden, T.; Dueck, A.; Nilsson, U.; Goudarzi, R.; Andersson, L.; Jensen, V.

    2012-01-01

    Document available in extended abstract form only. Bentonite is an excellent sealing material when it has reached full water saturation and swelling pressure. However, bentonite is not good for sealing inflowing water from fractures with potential to build high water pressure. It cannot stop inflow of water at the depth of a repository. The water inflow into the pellets filled slots in the deposition holes and the tunnels in a KBS-3V repository is expected to continue until these slots are water filled and the water flow stopped by an end plug. Then the water pressure gradient is transferred from the fracture/bentonite interface to the plug and the bentonite will have time to homogenize and seal. This scenario leads to a number of processes that can either be harmful to the bentonite or affect the water saturation and homogenization evolution. Last year a project (EVA) started in order to investigate the processes involved by this early water inflow. The project aims at developing a model for the processes piping, erosion, water filling of pellets filled slots, early water absorption and resulting water pressure increase against the plug. The project studies the effects of water inflow in deposition holes and deposition tunnels and the emergence of piping and erosion during installation and wetting of the buffer and backfill until all slots and the pellet fillings have been water filled and piping and erosion have ceased. The project includes laboratory tests of nine different processes and modeling. The laboratory program includes tests of the following processes: 1. Erosion; 2. Piping; 3. Water flow in pellet filled slots; 4. Sealing ability of bentonite; 5. Water absorption of the bentonite blocks; 6. Formation of water or gel pockets in a pellet filled slot; 7. Formation and outflow of bentonite gel; 8. Self-sealing of cracks by eroding water; 9. Buffer swelling before placement of backfill. The laboratory tests are ongoing and preliminary results and

  1. Evapotranspiración y eficiencia en el uso de agua en intercultivos maíz-soja vs cultivos puros Evapotranspiration and water use efficiency in maize-soybean intercrops and the sole crops

    Directory of Open Access Journals (Sweden)

    Cristian Valenzuela

    2009-12-01

    Full Text Available En este trabajo se evaluó la evapotranspiración real (ETR y la eficiencia en el uso de agua (EUA del intercultivo maíz-soja bajo dos arreglos espaciales y en los respectivos cultivos puros. El experimento se realizó en la Unidad Integrada Balcarce Facultad de Ciencias Agrarias, UNMdP-EEA INTA durante la campaña 2007-08. Los tratamientos fueron: a Intercultivo con dos surcos de soja y uno de maíz (2_1, b intercultivo con tres surcos de soja y dos de maíz (3_2, c maíz puro (M y d soja pura (S. El cultivo de maíz se sembró el 18/10 y el de soja el 3/12. La ETR acumulada entre la emergencia de maíz y la madurez fisiológica de soja fue de 586,7, 564,8, 570,5 y 596,0 mm para 2_1, 3_2, M y S, respectivamente. La EUA en biomasa (EUA B resultó significativamente más alta en M (44,5 kg-1mm-1 que en S (18,6 kg ha-1mm-1, 2_1 (35,3 kg ha-1mm-1 y 3_2 (35,3 kg ha-1mm-1. La EUA B de S fue significativamente menor que en los intercultivos. Las EUA en grano fueron 21,2, 5,5, 16,9 y 17,0 kg ha-1mm-1 para M, S, 2_1 e 3_2, respectivamente. La significancia de las diferencias entre tratamientos coincidió con la descripta para la EUA B.This work studies the real evapotranspiration (RET and the water use efficiency (WUE in a maize-soybean intercrop with two spatial arrangements and in their sole crops. The experiment was conducted in the UIB, FCA-UNMdP EEA INTA during the 2007-2008 season. Treatments were: a 2 rows soybeans and 1 row maize intercrop (2_1, b 3 rows soybean and 2 rows maize intercrop (3_2, c sole maize and d sole soybean. Crops were sown on October 18 (maize and December 3 (soybean. RET accumulated from maize emergence to soybean physiological maturity was 586,7, 564,8, 570,5 y 596,0 mm for 2_1, 3_2, sole maize and sole soybean, respectively. Water use efficiency (WUE as the quotient between accumulated shoot biomass and RET was significantly higher in sole maize (44,5 kg ha-1mm-1 than in sole soybean (18,6 kg ha-1mm-1, 2_1 (35,3 kg ha-1mm

  2. [Applicability of agricultural production systems simulator (APSIM) in simulating the production and water use of wheat-maize continuous cropping system in North China Plain].

    Science.gov (United States)

    Wang, Lin; Zheng, You-fei; Yu, Qiang; Wang, En-li

    2007-11-01

    The Agricultural Production Systems Simulator (APSIM) was applied to simulate the 1999-2001 field experimental data and the 2002-2003 water use data at the Yucheng Experiment Station under Chinese Ecosystem Research Network, aimed to verify the applicability of the model to the wheat-summer maize continuous cropping system in North China Plain. The results showed that the average errors of the simulations of leaf area index (LAI), biomass, and soil moisture content in 1999-2000 and 2000-2001 field experiments were 27.61%, 24.59% and 7.68%, and 32.65%, 35.95% and 10.26%, respectively, and those of LAI and biomass on the soils with high and low moisture content in 2002-2003 were 26.65% and 14.52%, and 23.91% and 27.93%, respectively. The simulations of LAI and biomass accorded well with the measured values, with the coefficients of determination being > 0.85 in 1999-2000 and 2002-2003, and 0.78 in 2000-2001, indicating that APSIM had a good applicability in modeling the crop biomass and soil moisture content in the continuous cropping system, but the simulation error of LAI was a little larger.

  3. Assessing winter cover crop nutrient uptake efficiency using a water quality simulation model

    OpenAIRE

    Yeo, I.-Y.; Lee, S.; Sadeghi, A. M.; Beeson, P. C.; Hively, W. D.; McCarty, G. W.; Lang, M. W.

    2014-01-01

    Winter cover crops are an effective conservation management practice with potential to improve water quality. Throughout the Chesapeake Bay watershed (CBW), which is located in the mid-Atlantic US, winter cover crop use has been emphasized, and federal and state cost-share programs are available to farmers to subsidize the cost of cover crop establishment. The objective of this study was to assess the long-term effect of planting winter cover crops to improve water quality a...

  4. Capillary electrophoretic profiling of tryptic digests of water soluble proteins from Bacillus thuringiensis-transgenic and non-transgenic maize species

    Czech Academy of Sciences Publication Activity Database

    Sázelová, Petra; Kašička, Václav; Leon, C.; Ibanez, E.; Cifuentes, A.

    2012-01-01

    Roč. 134, č. 3 (2012), s. 1607-1615 ISSN 0308-8146 R&D Projects: GA ČR(CZ) GA203/08/1428 Grant - others:AV ČR(CZ) 2008CZ0019 Institutional research plan: CEZ:AV0Z40550506 Keywords : Bt-transgenic maize * capillary zone electrophoresis * maize proteins Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.334, year: 2012

  5. Lake Mixing Regime Influences Arsenic Transfer from Sediments into the Water Column and Uptake in Plankton

    Science.gov (United States)

    Gawel, J.; Barrett, P. M.; Hull, E.; Burkart, K.; McLean, J.; Hargrave, O.; Neumann, R.

    2017-12-01

    The former ASARCO copper smelter in Ruston, WA, now a Superfund site, contaminated a large area of the south-central Puget Sound region with arsenic over its almost 100-year history. Arsenic, a priority Superfund contaminant and carcinogen, is a legacy pollutant impacting aquatic ecosystems in urban lakes downwind of the ASARCO emissions stack. We investigated the impact of lake mixing regime on arsenic transfer from sediments into lake water and aquatic biota. We regularly collected water column and plankton samples from four study lakes for two years, and deployed sediment porewater peepers and sediment traps to estimate arsenic flux rates to and from the sediments. In lakes with strong seasonal stratification, high aqueous arsenic concentrations were limited to anoxic hypolimnetic waters while low arsenic concentrations were observed in oxic surface waters. However, in polymictic, shallow lakes, we observed elevated arsenic concentrations throughout the entire oxic water column. Sediment flux estimates support higher rates of arsenic release from sediments and vertical transport. Because high arsenic in oxic