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Plant Science : An International... Oct 2015Legumes have a significant role in effective management of fertilizers and improving soil health in sustainable agriculture. Because of the high phosphorus (P)... (Review)
Review
Legumes have a significant role in effective management of fertilizers and improving soil health in sustainable agriculture. Because of the high phosphorus (P) requirements of N2-fixing nodule, P deficiency represents an important constraint for legume crop production, especially in tropical marginal countries. P deficiency is an important constraint for legume crop production, especially in poor soils present in many tropical degraded areas. Unlike nitrogen, mineral P sources are nonrenewable, and high-grade rock phosphates are expected to be depleted in the near future. Accordingly, developing legume cultivars with effective N2 fixation under P-limited conditions could have a profound significance for improving agricultural sustainability. Legumes have evolved strategies at both morphological and physiological levels to adapt to P deficiency. Molecular mechanisms underlying the adaptive strategies to P deficiency have been elucidated in legumes. These include maintenance of the P-homeostasis in nodules as a main adaptive strategy for rhizobia-legume symbiosis under P deficiency. The stabilization of P levels in the symbiotic tissues can be achieved through several mechanisms, including elevated P allocation to nodules, formation of a strong P sink in nodules, direct P acquisition via nodule surface and P remobilization from organic-P containing substances. The detailed biochemical, physiological and molecular understanding will be essential to the advancement of genetic and molecular approaches for enhancement of legume adaptation to P deficiency. In this review, we evaluate recent progress made to gain further and deeper insights into the physiological, biochemical and molecular reprogramming that legumes use to maintain P-homeostasis in nodules during P scarcity.
Topics: Fabaceae; Homeostasis; Phosphorus; Root Nodules, Plant
PubMed: 26398789
DOI: 10.1016/j.plantsci.2015.06.018 -
Environmental Science & Technology Mar 2024Socioeconomic factors and mitigation potentials are essential drivers of the dynamics of nutrient emissions, yet these drivers are rarely examined at broad...
Socioeconomic factors and mitigation potentials are essential drivers of the dynamics of nutrient emissions, yet these drivers are rarely examined at broad spatiotemporal scales. Here, we combine material flow analysis and geospatial analysis to examine the past and future changes of nitrogen and phosphorus emissions in China. Results show that anthropogenic nitrogen and phosphorus emissions increased by 17% and 32% during 2000-2019, respectively. Meanwhile, many regions witnessed decreasing nitrogen emissions but rising phosphorus discharged to waterbody, leading to a 20% decrease in the nitrogen/phosphorus ratio. In addition to many prominent factors like fertilizer use, the increasing impervious land area around cities is a notable factor driving the emissions, indicating the urgency to limit building expansion, especially in North China Plain and other less-developed regions. Improving land-use efficiency and consuming behaviors could reduce nitrogen and phosphorus emissions by 65-77% in 2030, but the nitrogen/phosphorus ratio will increase unintendedly due to larger reduction potentials for phosphorus, which may deteriorate the aquatic ecosystem. We highlight that nitrogen and phosphorus emissions should be reduced with coordinated but differentiated measures by prioritizing nitrogen reduction through cropland and food-system management.
Topics: Nitrogen; Phosphorus; Ecosystem; Agriculture; Food; China
PubMed: 38417148
DOI: 10.1021/acs.est.3c07298 -
Water Science and Technology : a... 2016Simultaneous nitrification and denitrifying phosphorus removal was achieved in a single-sludge continuous flow bioreactor. The upright bioreactor was aligned with a...
Simultaneous nitrification and denitrifying phosphorus removal was achieved in a single-sludge continuous flow bioreactor. The upright bioreactor was aligned with a biomass fermenter (BF) and operated continuously for over 350 days. This study revealed that unknown bacteria of the Saprospiraceae class may have been responsible for the successful nutrient removal in this bioreactor. The successive anoxic-aerobic stages of the bioreactor with upright alignment along with a 60 L BF created a unique ecosystem for the growth of nitrifier, denitrifiers, phosphorus accumulating organisms and denitrifying phosphorus accumulating organisms. Furthermore, total nitrogen to chemical oxygen demand (COD) ratio and total phosphorus to COD ratio of 0.6 and 0.034, respectively, confirmed the comparative advantages of this advanced nutrient removal process relative to both sequencing batch reactors and activated sludge processes. The process yielded 95% nitrogen removal and over 90% phosphorus removal efficiencies.
Topics: Bacteria; Biological Oxygen Demand Analysis; Bioreactors; Denitrification; Nitrification; Nitrogen; Phosphorus; Sewage; Waste Disposal, Fluid; Water Pollutants, Chemical
PubMed: 27148710
DOI: 10.2166/wst.2016.057 -
Environmental Science and Pollution... Nov 2019Eggshell ash was used as an adsorbent to remove phosphorus from wastewater. Adsorbent dose, initial phosphorus concentration, and contact time were investigated to...
Eggshell ash was used as an adsorbent to remove phosphorus from wastewater. Adsorbent dose, initial phosphorus concentration, and contact time were investigated to determine the optimum conditions. Results indicate that 5 g of eggshell ash adsorbent with 1.5 mg L of initial phosphorus concentration removed over 90% of the phosphorus. When the temperature was increased, phosphorus removal potential also increased. Specific surface area, morphological features, and structure of the adsorbent were characterized by Brunauer-Emmett-Teller (BET) surface area analysis, scanning electron microscopy with energy dispersive X-ray spectrometer (SEM-EDS), and X-ray diffraction (XRD). Results showed prominent calcium, magnesium, and phosphorus in the eggshell ash surface after adsorption. The elemental composition of eggshell ash surfaces before adsorption did not contain phosphorus, revealing that calcium carbonate-based eggshell ash was co-precipitated with calcium phosphate. The adsorption mechanism was studied by applying Langmuir and Freundlich isotherm models. Experimental data fit well with the Langmuir model, which indicates monolayer adsorption. Eggshell ash was also applied as an adsorbent in wastewater at Srinakharinwirot University dormitories, resulting in 80% phosphorus removal within 2 h. These findings indicated that eggshell ash could be applied as an adsorbent for phosphorus treatment and removal from domestic and industrial wastewater.
Topics: Adsorption; Animals; Calcium Carbonate; Egg Shell; Hydrogen-Ion Concentration; Kinetics; Phosphorus; Temperature; Waste Disposal, Fluid; Wastewater; Water Pollutants, Chemical; X-Ray Diffraction
PubMed: 30276697
DOI: 10.1007/s11356-018-3305-3 -
Wei Sheng Wu Xue Bao = Acta... Mar 2015Eutrophication has raised increasing concerns due to its adverse effects on creatures. It is widely accepted that microbes are capable of removing nitrogen (N) and... (Review)
Review
Eutrophication has raised increasing concerns due to its adverse effects on creatures. It is widely accepted that microbes are capable of removing nitrogen (N) and phosphate (P) via denitrification and P accumulation. So far, several strains can do this work. Therefore, more studies are focused on looking for micro-organisms that have both denitrification and P accumulation ability. Whether exposed to aerobic or anaerobic environment, microbial N and P removal mechanisms differ. Proton Motive Force and Electron Acceptor Theory are involved in the chemical process, whereas denitrifying enzymes polyphosphate kinases are regarded as the leading participators in the enzymatic systems. Studies have shown the influences of N on P accumulation, but further investigation should identify the influences of P on N removal. Here we reviewed the aspects of N and P removal mechanisms in denitrifying phosphorus accumulating organisms (DPAOs) and their potential to remove N and P from water system. Moreover, future works on clarifying denitrifying phosphorus accumulating mechanisms in depth and improving efficiency of removing N and P by DPAOs are provided.
Topics: Bacteria; Biodegradation, Environmental; Denitrification; Phosphorus; Wastewater; Water Purification
PubMed: 26065268
DOI: No ID Found -
Open Biology Jan 2018Molecular and genomic studies have shown the presence of a large number of gene family members in plants, some of which have been proved to act in P signalling and... (Review)
Review
Molecular and genomic studies have shown the presence of a large number of gene family members in plants, some of which have been proved to act in P signalling and homeostasis. In this study, the molecular and evolutionary characteristics of the gene family in plants were comprehensively analysed, and the mechanisms underlying the function of genes in P signalling and homeostasis in the model plant species () and rice (), and in important crops, including wheat (), soya beans () and rapeseed (), were described. Emerging findings on the involvement of genes in other important processes (i.e. disease resistance, iron deficiency response, low oxygen response and phytochrome-mediated light signalling) were also highlighted. The available data suggest that genes are important regulators in the P signalling network, and may be valuable targets for enhancing crop tolerance to low P stress. Further studies on SPX proteins should include more diverse members, which may reveal SPX proteins as important regulatory hubs for multiple processes including P signalling and homeostasis in plants.
Topics: Crops, Agricultural; Evolution, Molecular; Phosphorus; Plant Proteins; Stress, Physiological
PubMed: 29298909
DOI: 10.1098/rsob.170231 -
Water Research Aug 2022The framework, model and methods of Nürnberg were applied and evaluated in Lough Neagh and 19 other lakes in order to establish inflow phosphorus concentrations that...
The framework, model and methods of Nürnberg were applied and evaluated in Lough Neagh and 19 other lakes in order to establish inflow phosphorus concentrations that support target lake values. Supporting concentrations, in the absence of an internal load, were derived and the effect of uncertainty in the model retention coefficient was relatively small, ±11-20 % in Lough Neagh and an average (n = 17) of ±9.7 % in the other lakes. There was further support for the model and methods from an independent estimate of the net internal load in Lough Neagh (13 % difference) and from another model in the other lakes (Supporting concentrations, which should be lower, were by an average of 11 mg P m). In the framework, steady state with the phosphorus load is assumed, but, based on a generic lake model, is not likely if the hydraulic residence time>0.5-0.8 yr and should lead to a decrease in phosphorus retention, which was found during three periods in Lough Neagh. Based on a compilation of internal load recovery times from 23 lakes in the literature, it could take between 8 and 20 years for lakes with an internal load to approach their targets.
Topics: Environmental Monitoring; Eutrophication; Lakes; Nitrogen; Phosphorus
PubMed: 35872519
DOI: 10.1016/j.watres.2022.118858 -
The Science of the Total Environment Jul 2023Due to the phosphorus (P) deficiency in coking wastewater, sufficient P needs to be provided in the treatment process to maintain biotic activity. However, most of the...
Due to the phosphorus (P) deficiency in coking wastewater, sufficient P needs to be provided in the treatment process to maintain biotic activity. However, most of the dosed P sources are transferred to the sludge phase out of the chemical equilibrium. After an in-depth investigation of P morphology changes in coking wastewater treatment, it is found that above 71.6 % P applied to the full-scale O/H/H/O (oxic-hydrolytic & denitrification-hydrolytic & denitrification-oxic) process for coking wastewater treatment is ended up in the sludge phase of the aerobic reactors in the forms of non-apatite inorganic phosphorus (NAIP). Theoretical simulations suggest that the P forms precipitates such as FePO·2HO, AlPO·2HO, MnHPO at pH < 7, and Ca(PO)OH at pH > 7. Microbial utilization of P in coking wastewater treatment is swayed by precipitation, pH and sludge retention time (SRT). By pyrolysis treatment of the waste sludge at 700 °C, phosphoric substances in coking sludge are enriched and converted into Ca(PO)OH, Ca(PO)Cl, Ca(PO), etc. with apatite phosphorus (AP) accounting for 65.7 % of total phosphorus. Moreover, the heavy metals in biochar were below the national standard limits for discharge. This study shows that hazardous waste (coking sludge) can be transformed into bioavailable products (P-rich biochar) through comprehensive management of the fate of P. Combined with the O/H/H/O process, the mechanisms of phosphorus consumption in coking wastewater treatment are revealed for the first time, which will facilitate a reduced consumption of phosphorus and provide a demonstration for other phosphorus-deficient industrial wastewater treatment.
Topics: Wastewater; Sewage; Phosphorus; Coke
PubMed: 37044344
DOI: 10.1016/j.scitotenv.2023.163384 -
Chemosphere May 2020This study investigated phosphorus (P) dynamics in the sediment-water interface of three distinct reservoirs located in a tropical semiarid region. Sequential chemical...
This study investigated phosphorus (P) dynamics in the sediment-water interface of three distinct reservoirs located in a tropical semiarid region. Sequential chemical fractioning of the P content in the sediment and controlled experiments of the sediment-water interface were performed to understand and model the effect of the different P fractions on the exchange dynamics under anoxic and oxic scenarios. The results revealed that the older the reservoir, the higher the amount of iron and aluminum-bound P in the sediment, and that this fraction was responsible for a 10-fold increase in P concentration in the water during anoxic conditions. After aeration, P in water decreased but did not return to its initial concentration. The most recently constructed reservoir showed the lowest P concentration in the sediment and dominance of the unavailable P fraction, resulting in no potential impact on water quality. Phosphorus release and precipitation rates were well described by zero- and first-order models, respectively. Reservoirs with high P availability in the sediment, not only released more phosphorus but also presented a lower precipitation rate, resulting in higher potential damage to water quality and making some in-lake treatment techniques potentially ineffective.
Topics: Aluminum; China; Eutrophication; Geologic Sediments; Iron; Lakes; Models, Chemical; Phosphorus; Water; Water Pollutants, Chemical; Water Quality
PubMed: 31918079
DOI: 10.1016/j.chemosphere.2019.125686 -
Journal of Agricultural and Food... Jun 2023Solid-state magic angle spinning P NMR spectroscopy is used to identify and quantify phosphorus-containing species in pet foods. The measurement is challenging due to...
Solid-state magic angle spinning P NMR spectroscopy is used to identify and quantify phosphorus-containing species in pet foods. The measurement is challenging due to the long spin-lattice relaxation times (s). Data acquisition times are shortened by acquiring data with a tip angle smaller than 90° and shortening the repetition time. However, the spin-lattice relaxation times (s) of the different P compounds are quite different, necessitating a separate measurement for each compound in the pet food. Knowledge of is used to calculate the relative amount of P in the samples. Samples of known concentration are also measured, enabling the quantitative measurement of total phosphorus content.
Topics: Phosphorus; Magnetic Resonance Spectroscopy
PubMed: 37227713
DOI: 10.1021/acs.jafc.2c07339