scholarly journals The Cumulative Amount of Exuded Citrate Controls Its Efficiency to Mobilize Soil Phosphorus

2020 ◽  
Vol 3 ◽  
Author(s):  
Helmer Schack-Kirchner ◽  
Caroline A. Loew ◽  
Friederike Lang
Keyword(s):  
Solid Phase ◽  
Root Exudation ◽  
P Uptake ◽  
Soil Horizon ◽  
Background Concentration ◽  
Batch Experiments ◽  
Sink Term ◽  
P Mobilization ◽  
Over Time ◽  
Citrate Efflux

Root exudation of citrate is discussed as mechanism to mobilize P from the soils' solid phase. Microbial processes can mitigate the mobilization efficiency of citrate. Due to higher microbial activity in topsoils compared to subsoils, we hypothesized a lower mobilization efficiency of exuded citrate in topsoils than in the subsoils. As a model system we used microdialysis (MD) probes and we followed diffusive fluxes of citrate from the perfusate into the soil and of phosphate from the soil into the dialysate in three soil horizons (Oa, Ah, Bw) of a Fagus sylvatica L. stand Cambisol. Three different MD perfusates with a KCl background concentration have been used: control, 1, and 3 mmol L−1 citric acid. Fluxes have been measured after 24, 48, and 144 h. The high-citrate perfusate increased the cumulative 144 h P-influx by a factor of 8, 13, and 113 in the Oa, Ah, and Bw horizon, respectively. With the high-citrate treatment, P mobilization efficiency decreased over time, whereas for the low citrate, P mobilization efficiency had a maximum at day 2. Minimum P mobilization efficiency of citrate was 1:25,000 mol phosphate per mol citrate in the Oa horizon between days 2 and 6, and maximum was 1:286 in the Bw-horizon during day 2. An increasing citrate efflux over time indicated an increasing sink term for citrate in the soil due to microbial decay or immobilization processes. Cumulative phosphate influx could be fitted to cumulative citrate efflux and soil horizon in a logarithmic model explaining 87% of the variability. For the first time, we could follow the localized P-uptake with citrate exudation over several days. Cumulative citrate efflux as the main control of P-mobilization has been barely discussed yet, however, it could explain some gaps in the role of carboxylates in the rhizosphere. Batch experiments are not capable to elucidate microscale dynamic competition for phosphate and carboxylates. MD is a promising tool for spatially explicit investigation of phosphate–citrate exchange, since such detailed insights in are not possible with batch experiments. In combination with the analysis of microbial properties, this technique has a huge potential to identify mobilization processes in soils as induced by citrate.

scholarly journals Elucidation of the Volatilome of Packaged Spanish-Style Green Olives of Conservolea and Halkidiki Varieties Using SPME-GC/MS

Proceedings ◽  
2020 ◽  
Vol 70 (1) ◽  
pp. 75
Author(s):  
Alexandra Nanou ◽  
Athanasios Mallouchos ◽  
Efstathios Z. Panagou
Keyword(s):  
Volatile Compounds ◽  
Solid Phase ◽  
Acid Ethyl Ester ◽  
Volatile Components ◽  
Propanoic Acid ◽  
Qualitative Composition ◽  
Organoleptic Characteristics ◽  
Increasing Trend ◽  
Volatile Profiles ◽  
Over Time

Olives are characterized by a wide variety of volatile compounds, which are primarily products of microbial metabolism that contribute to the organoleptic characteristics of the final product and especially to its flavor. The volatilome in Spanish-style processed green olives of Conservolea and Halkidiki cultivars were analytically characterized. A solid phase micro-extraction (SPME) technique was used for the extraction of volatile components from the olive samples that were further identified and quantified by gas chromatography coupled to mass spectrometry (GC–MS). Eighty-eight (88) compounds were identified, including several aldehydes, ketones, acids, terpenes, but mainly esters and alcohols. Results showed that there were no significant differences in the qualitative composition of the volatile profiles between the two varieties. Acetic and propanoic acids, thymol, ethanol, 2-butanol, 1-propanol, ethyl acetate as well as ethyl propanoate were the most dominant compounds found in both cultivars. However, some quantitative differences were spotted between the two varieties regarding some of the identified volatile compounds. The quantity of 2-butanol was higher in the Halkidiki variety, while propanoic acid ethyl ester was found in higher amounts in the Conservolea variety. Furthermore, differences in the quantities of some volatile compounds over time were observed. Most of the identified compounds presented an increasing trend during storage.

scholarly journals On the potential vegetation feedbacks that enhance phosphorus availability – insights from a process-based model linking geological and ecological timescales

2014 ◽  
Vol 11 (13) ◽  
pp. 3661-3683 ◽  
Author(s):  
C. Buendía ◽  
S. Arens ◽  
T. Hickler ◽  
S. I. Higgins ◽  
P. Porada ◽  
...  
Keyword(s):  
Biomass Production ◽  
Primary Productivity ◽  
Chemical Weathering ◽  
Production Efficiency ◽  
Root Exudation ◽  
Terrestrial Ecosystems ◽  
Global Scale ◽  
P Uptake ◽  
P Availability ◽  
P Limitation

Abstract. In old and heavily weathered soils, the availability of P might be so small that the primary production of plants is limited. However, plants have evolved several mechanisms to actively take up P from the soil or mine it to overcome this limitation. These mechanisms involve the active uptake of P mediated by mycorrhiza, biotic de-occlusion through root clusters, and the biotic enhancement of weathering through root exudation. The objective of this paper is to investigate how and where these processes contribute to alleviate P limitation on primary productivity. To do so, we propose a process-based model accounting for the major processes of the carbon, water, and P cycles including chemical weathering at the global scale. Implementing P limitation on biomass synthesis allows the assessment of the efficiencies of biomass production across different ecosystems. We use simulation experiments to assess the relative importance of the different uptake mechanisms to alleviate P limitation on biomass production. We find that active P uptake is an essential mechanism for sustaining P availability on long timescales, whereas biotic de-occlusion might serve as a buffer on timescales shorter than 10 000 yr. Although active P uptake is essential for reducing P losses by leaching, humid lowland soils reach P limitation after around 100 000 yr of soil evolution. Given the generalized modelling framework, our model results compare reasonably with observed or independently estimated patterns and ranges of P concentrations in soils and vegetation. Furthermore, our simulations suggest that P limitation might be an important driver of biomass production efficiency (the fraction of the gross primary productivity used for biomass growth), and that vegetation on old soils has a smaller biomass production rate when P becomes limiting. With this study, we provide a theoretical basis for investigating the responses of terrestrial ecosystems to P availability linking geological and ecological timescales under different environmental settings.

scholarly journals Dual Inoculation With Arbuscular Mycorrhizal Fungi and Phosphorus Solubilizing Fungi Synergistically Enhances the Mobilization and Plant Uptake of Phosphorus From Meat and Bone Meal

2021 ◽  
Vol 1 ◽  
Author(s):  
Bhupinder Singh Jatana ◽  
Christopher Kitchens ◽  
Christopher Ray ◽  
Patrick Gerard ◽  
Nishanth Tharayil
Keyword(s):  
Arbuscular Mycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
P Uptake ◽  
Mineral Nutrient ◽  
Meat And Bone Meal ◽  
Bone Meal ◽  
Simultaneous Application ◽  
Plant P Uptake ◽  
P Mobilization

Phosphorus (P) is the second most important mineral nutrient for plant growth and plays a vital role in maintaining global food security. The natural phosphorus reserves [phosphate rock (PR)] are declining at an unprecedented rate, which will threaten the sustainable food supply in near future. Rendered animal byproducts such as meat and bone meal (MBM), could serve as a sustainable alternative to meet crop phosphorus demand. Even though nitrogen (N) from MBM is readily mineralized within a few days, >75% of the P in MBM is present as calcium phosphate that is sparingly available to plants. Thus, application of MBM with the aim of meeting crop N demand could result in buildup of P reserves in soil, which necessitates the need to improve the P mobilization from MBM to achieve higher plant P use efficiency. Here, we tested the potential of two microbial inoculum-arbuscular mycorrhizal fungi (AMF) and P solubilizing fungi (Penicillium bilaiae), in improving the mobilization of P from MBM and the subsequent P uptake by maize (Zea mays). Compared to the non-inoculated MBM control, the application of P. bilaiae increased the P mobilization from MBM by more than two-fold and decreased the content of calcium bound P in the soil by 26%. However, despite this mobilization, P. bilaiae did not increase the tissue content of P in maize. On the other hand, AMF inoculation with MBM increased the plant root, shoot biomass, and plant P uptake as compared to non-inoculated control, but did not decrease the calcium bound P fraction of the soil, indicating there was limited P mobilization. The simultaneous application of both AMF and P. bilaiae in association with MBM resulted in the highest tissue P uptake of maize with a concomitant decrease in the calcium bound P in the soil, indicating the complementary functional traits of AMF and P. bilaiae in plant P nutrition from MBM. Arbuscular mycorrhizal fungi inoculation with MBM also increased the plant photosynthesis rate (27%) and root phosphomonoesterase activity (40%), which signifies the AMF associated regulation of plant physiology. Collectively, our results demonstrate that P mobilization and uptake efficiency from MBM could be improved with the combined use of arbuscular mycorrhizal fungi and P. bilaiae.

scholarly journals REMEDIATION OF THE POLLUTANT CONTENT OF RUNOFF WATER FROM A CONTAINERIZED PLANT NURSERY

HortScience ◽  
1995 ◽  
Vol 30 (3) ◽  
pp. 433a-433
Author(s):  
Jeanne A. Briggs ◽  
Mellissa B. Riley ◽  
Ted Whitwell
Keyword(s):  
Solid Phase Extraction ◽  
Solid Phase ◽  
Typha Latifolia ◽  
Phase Extraction ◽  
Runoff Water ◽  
Overhead Irrigation ◽  
Plant Nursery ◽  
Nursery Runoff ◽  
Over Time ◽  
Container Nursery

The pesticides isoxaben, trifluralin, chlorpyrifos, and thiophanatemethyl were applied at recommended rates to a 4-ha growing bed at an operating container nursery. Runoff samples produced by overhead irrigation were collected from three waterways, 300 feet long × 6 feet wide. The waterways were a sodded hybrid bermudagrass, a plantation of common cattails (Typha latifolia), and a gravel–clay waterway used as a reference. A 2-ha area drained into the sodded waterway, which flowed into the cattails, and a 2-ha bed flowed into the reference waterway. Samples were collected throughout the duration of runoff on day of treatment and at 1, 2, 8, 15, and 22 days after treatment. Runoff volumes were recorded over time as measured at weirs. Analysis was by HPLC following solid-phase extraction. Only isoxaben was detected at 2 days after treatment. Initial concentrations of all pesticides were lower in the vegetated waterways than in the reference.

scholarly journals Volatile Compounds Emitted from the Cat Urine Contaminated Carpet Before and After Treatment with Marketed Cleaning Products: A Simultaneous Chemical and Sensory Analysis

2020 ◽  
Author(s):  
Chumki Banik ◽  
Jacek Koziel ◽  
Elizabeth Flickinger
Keyword(s):  
Solid Phase ◽  
Micrococcus Luteus ◽  
Household Dust ◽  
Water Control ◽  
Cleaning Products ◽  
Before And After ◽  
Obligate Aerobe ◽  
Urine Contamination ◽  
The Impact ◽  
Over Time

Urination on carpet and subflooring can develop into persistent and challenging to mitigate odor. Very little or no information is published on how these VOCs change over time when urine is deposited on the carpet covering a plywood-type subflooring. This research has investigated the VOCs emitted from carpet+subflooring (control), carpet+subflooring sprayed with water (control with moisture), and cat urine-contaminated carpet+subflooring (treatment) over time (day 0 and 15). In addition, the effect of popular cleaning products on VOCs emitted and evaluated their efficacy in eliminating those indoor odors over time (day 0 and 15). Carpet-subflooring with all treatments were also contaminated with Micrococcus luteus, nonmotile obligate aerobe commonly found in household dust, to observe the impact of the aerobe on carpet-subflooring VOCs emission. VOCs emitted from carpet+subflooring receiving different treatments were collected from headspace using solid-phase microextraction (SPME). The VOCs were analyzed using a multidimensional gas chromatography-mass spectrometer attached to an olfactometry (GC-MS-O). Many common VOCs were released from the carpet on day one and day fifteen, specifically from urine contamination. Cleaning products were effective in masking several potent odors of cat urine contaminated carpet VOCs on day one but unable to remove the odor appeared on day 15 in most cases.

EXPRESS: Chemical Characterization Using Laser-Induced Breakdown Spectroscopy of Products Released from Lithium-Ion Battery Cells at Thermal Runaway Conditions

2021 ◽  
pp. 000370282110552
Author(s):  
Daniel Diaz ◽  
David W Hahn
Keyword(s):  
Solid Phase ◽  
Chemical Characterization ◽  
Lithium Ion ◽  
Thermal Runaway ◽  
Laser Induced Breakdown Spectroscopy ◽  
Breakdown Spectroscopy ◽  
Laser Induced Breakdown ◽  
Li Ion ◽  
Over Time ◽  
Battery Cells

Laser-induced breakdown spectroscopy (LIBS) was used to characterize the materials released by lithium-ion (Li-ion) cells at thermal runaway conditions. Commercial AAA-size, rechargeable, 3.7-V, 350-mAh, Li-ion battery cells were heated in a N2-atmosphere tubular chamber up to about 165 °C to induce thermal decomposition. Through measurements of the chamber internal temperature and LIBS emission intensities over time the onset temperature of thermal runaway (≈143 °C) and the duration of the cells outgassing (> 40 minutes) were determined. Relatively high intensity atomic emissions from C, H, F, Li, Na, and P were detected at different times during the heating experiments. The detection of analytes such as C and H was continuous over time. On the contrary, detection of F, Na, Li, and P was more irregular, indicating the presence of solid-phase analytes or analyte-bearing particles. A calibration scheme for estimation of the total mass/volume concentration of all carbon-based species sampled within the laser-induced plasma was developed.

Effects of aging and transformation of Fe(III)-precipitates on the retention of co-precipitated phosphate

2021 ◽  
Author(s):  
Ville Nenonen ◽  
Ralf Kaegi ◽  
Stephan J. Hug ◽  
Stefan Mangold ◽  
Jörg Göttlicher ◽  
...  
Keyword(s):  
Natural Waters ◽  
Colloidal Stability ◽  
P Uptake ◽  
Oxidation Products ◽  
Structure Stability ◽  
Retention Capacity ◽  
X Ray ◽  
P Release ◽  
P Retention ◽  
Over Time

<p>The cycling of phosphorus in terrestrial and aquatic systems is tightly coupled to the redox-cycling of iron (Fe). The oxidation of dissolved Fe(II) in natural waters leads to the precipitation of amorphous to poorly crystalline Fe(III)-solids that can bind phosphate (P) and other nutrients as well as toxic compounds. The EU project P-TRAP is aimed at developing methods to reduce diffuse P inputs into surface waters to mitigate eutrophication, by using Fe-rich byproducts from water treatment (https://h2020-p-trap.eu/). Within this project, we study mechanistic aspects of the formation and transformation of P-containing Fe(III)-precipitates and their implications for P retention in soils and water filters.</p><p>Freshly formed Fe(III)-precipitates are metastable and can transform into more stable phases over time. This may lead to the release of co-precipitated P. In laboratory experiments, we assessed how Ca, Mg, silicate (Si) and P impact on the formation and transformation of Fe oxidation products (at 0.5 mM Fe) and their P retention in synthetic bicarbonate-buffered groundwater. The time-resolved experiments were performed in electrolyte solutions containing Na, Ca, or Mg as electrolyte cation, without or with Si (at molar Si/Fe of 1), and P (P/Fe of 0.3 and 0.05). Changes in dissolved element concentrations over time were linked to changes in the structure and composition of the Fe(III)-solids; with Fe coordination probed by X-ray absorption spectroscopy, mineralogy by X-ray diffraction, and nano-scale morphology and composition heterogeneity by transmission electron microscopy with energy-dispersive X-ray detection.</p><p>The freshly-formed Fe(III)-precipitates were mixtures of amorphous Fe(III)-phosphate with either poorly-crystalline lepidocrocite (without Si) or Si-containing ferrihydrite (with Si). Increases in dissolved P during aging were largest in Na electrolytes without Ca, Mg or Si, and were linked to the transformation of amorphous Fe(III)-phosphate into lepidocrocite with a lower P retention capacity than Fe(III)-phosphate. In Ca- and to a lesser extent Mg-containing electrolytes, the Ca or Mg stabilized the amorphous Fe(III)-phosphate and thereby reduced P release over time. The presence of Si increased initial P uptake and inhibited P release during aging by causing the formation of Si-ferrihydrite with higher P sorption capacity than lepidocrocite formed in the absence of Si. In conclusion, the extents to which P is trapped by fresh Fe(III)-precipitates and released during aging can be attributed to the individual and coupled impacts of Ca, Mg and Si on Fe(III)-precipitate structure, stability and transformation.</p><p>In continuing work, we aim to expand our work to study how organic compounds impact on the formation and colloidal stability of Fe(III)-precipitates and P retention.</p>

scholarly journals Drug Testing in Blood: Validated Negative-Ion Chemical Ionization Gas Chromatographic–Mass Spectrometric Assay for Enantioselective Measurement of the Designer Drugs MDEA, MDMA, and MDA and Its Application to Samples from a Controlled Study with MDMA

2005 ◽  
Vol 51 (10) ◽  
pp. 1811-1822 ◽  
Author(s):  
Frank T Peters ◽  
Nele Samyn ◽  
Caroline TJ Lamers ◽  
Wim J Riedel ◽  
Thomas Kraemer ◽  
...  
Keyword(s):  
Drug Testing ◽  
Chemical Ionization ◽  
Solid Phase ◽  
Designer Drugs ◽  
Negative Ion ◽  
Controlled Study ◽  
Intermediate Precision ◽  
Precision Data ◽  
Negative Ion Chemical Ionization ◽  
Over Time

Abstract Background: The enantiomers of the designer drugs 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), and 3,4-methylenedioxyethylamphetamine (MDEA) differ in their pharmacologic and toxicologic potency. The aim of this study was to develop an assay for measuring these enantiomers in small plasma volumes and to analyze samples from a controlled study with MDMA. Methods: The analytes were extracted from ≤0.2 mL of plasma by mixed-mode solid-phase extraction. After derivatization with S-(−)-heptafluorobutyrylprolyl chloride, the resulting diastereomers were separated by gas chromatography (HP-5MS) within 17 min and detected by mass spectrometry in the negative-ion chemical ionization mode. The method was fully validated and applied to samples from a controlled study in which a single dose of racemic MDMA (75 mg) was administered. Results: The derivatized enantiomers were well separated and detected with good sensitivity. The assay was linear (per enantiomer) at 1–50 μg/L for MDA and 5–250 μg/L for MDMA and MDEA. Analytical recovery, accuracy, repeatability, and intermediate precision data were within required limits. Extraction yields were 82.1%–95.3%. In the study samples, concentrations of R-(−)-MDMA significantly exceeded those of S-(+)-MDMA. Their ratios (R vs S) were always >1.0 and increased over time. Concentrations of S-(+)-MDA exceeded those of R-(−)-MDA, their ratios (R vs S) also increasing over time but remaining <1.0. Conclusions: This assay enables sensitive, reliable, and fast enantioselective measurement of MDA, MDMA, and MDEA in small volumes of plasma. The controlled study data confirm previous findings of MDMA and MDA enantiomer ratios (R vs S) increasing over time after ingestion of racemic MDMA.

scholarly journals SPME collection and GC-MS analysis of volatiles emitted during the attack of male Polygraphus poligraphus (Coleoptera, Curcolionidae) on Norway spruce

2015 ◽  
Vol 70 (9-10) ◽  
pp. 265-273 ◽  
Author(s):  
Rizan Rahmani ◽  
Erik Hedenström ◽  
Martin Schroeder
Keyword(s):  
Norway Spruce ◽  
Bark Beetle ◽  
Bark Beetles ◽  
Tree Mortality ◽  
Solid Phase ◽  
Enantiomeric Excess ◽  
Enantiomeric Purity ◽  
Spruce Bark ◽  
Volatile Organic ◽  
Over Time

Abstract Tree mortality caused by bark beetles has increased in recent decades in both Europe and North America. In a large recent outbreak in central Sweden the bark beetle Polygraphus poligraphus was often found together with the spruce bark beetle Ips typographus in killed trees. To increase the understanding of the aggregation behavior of P. poligraphus we used solid phase microextraction (SPME) to collect volatile organic compounds (VOCs) released from single P. poligraphus males, with and without added females, colonizing Norway spruce stem sections and analyzed the sampled compounds by combined gas chromatography and mass spectrometry (GC-MS). High amounts of terpinen-4-ol, a substance found in the hindguts of P. poligraphus males in earlier studies, were released by colonizing males. The emission of both enantiomers of terpinen-4-ol was monitored by GC-MS over time as the males aged in the absence and presence of females. Single males emitted (R)-(–)-terpinen-4-ol for up to 60 days in high enantiomeric purity but the enantiomeric excess (ee) varied between males, and also for the same individual, over time from 96.3% to 99.3% ee. In the presence of females, males also emitted terpinen-4-ol for up to 50 days but now in lower amounts and with lower enantiomeric purity varying from 67.7% ee to 99.3% ee. Small quantities of other volatile compounds were emitted from the colonizing beetles including cis- and trans-4-thujanol, both of which were previously shown to be present in the hindguts of males. In earlier studies frontalin was found to attract P. poligraphus, but in our study it was not identified among emitted compounds from colonizing beetles.

Europium interaction with a vault backfill at high pH

2012 ◽  
Vol 76 (8) ◽  
pp. 3083-3093 ◽  
Author(s):  
R. Telchadder ◽  
K. Smith ◽  
N. D. Bryan
Keyword(s):  
Ethylenediaminetetraacetic Acid ◽  
Solid Phase ◽  
Sorption Properties ◽  
Batch Experiments ◽  
Crushed Material ◽  
High Ph ◽  
Temporary Suspension ◽  
High Concentrations ◽  
Apparent Equilibrium

AbstractBatch experiments have been used to assess the sorption properties of a potential cementitious repository backfill, NRVB (Nirex reference vault backfill), using Eu3+ as a model trivalent radionuclide and ethylenediaminetetraacetic acid (EDTA) as a competing ligand. The NRVB is an effective scavenger of Eu from solution, with most sorbed within minutes onto the crushed material and less than 1.5% remaining in solution after one day (Rd values in the range 0.3–2.4 × 104 l kg−1). Ultrafiltration showed that nearly all of this remaining Eu (>94%) is attached to NRVB derived colloids or particulates that are mainly retained by a 100 kDa ultrafilter. High concentrations of EDTA (>0.01 M) reduced the extent of sorption at apparent equilibrium. The addition of EDTA to a pre-equilibrated system of Eu3+ and NRVB resulted in a temporary suspension of some Eu, but this very quickly returned to the solid phase. There is some irreversibility in these systems, with EDTA able to prevent removal of Eu(III) from solution, but unable to bring it back into solution under the same conditions.

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