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PubMedDate not supplied

[Effect of humus and microbial inoculates on yield and nitrogen uptake by agricultural plants].

The application of humus had a positive effect on grain and straw yield of paddy and the yield increased with the increasing concentration of humus. The highest dose ((0,05%) corresponding to 1120 kg humus/ha significantly increased the grain and straw yield by 85 and 30 per cent over control. The efficiency of algal inoculation was enhanced in the presence of humus and recorded 41 per cent increase in yield over algae. The nitrogen uptake was also appreciably increased by grain and straw due to humus application. Humus at 0,05 per cent along with algae significantly increased the nitrogen uptake by paddy over algae alone. Root nodulation, growth and yield of gram crop were appreciably increased due to humus application. The grain and straw yield were increased due to humus (0,05%) application showing 32 and 41 per cent increase over control. The efficiency of Rhizobium inoculation was also improved in the presence of humus and the grain and straw yield was significantly increased.

Eukaryota↗

PubMed2006

Increasing milking intervals decreases the mammary blood flow and mammary uptake of nutrients in dairy cows.

Increasing the milking intervals reduces milk yield. The aims of this study were to determine whether the reduction in milk yield could be explained by a decrease in mammary uptake of the nutrients or a decrease in the efficiency of the mammary gland in using the milk precursors to synthesize milk components, or both. In a Latin square design with 5 periods, 4 multiparous lactating dairy cows in midlactation were milked at 8-, 12-, 16-, or 24-h intervals over a period of 7 d. The cows were surgically prepared to estimate the net mammary balance of nutrient precursors of milk components (glucose, alpha-amino nitrogen, acetate, beta-hydroxybutyrate, and total glycerol). The efficiency of the mammary gland in synthesizing milk components was estimated by the mammary uptake:milk output ratio. After 7 d of treatment, the decrease in milk yield of 6.1 kg/d between 8- and 24-h milking intervals was associated with a reduction in the uptake of nutrients by the mammary gland, whereas the efficiency of the mammary gland in synthesizing milk components remained relatively unchanged. The mammary uptake decreased by 26% for glucose, 32% for alpha-amino nitrogen, 18% for acetate, 24% for total glycerol, and 24% for beta-hydroxybutyrate, respectively. These reductions in nutrient uptake were due to a decrease in the mammary blood flow (1.23 +/- 0.24 L/min). For milk fat precursors (acetate, beta-hydroxybutyrate, and total glycerol), the decrease in mammary blood flow explained the entire reduction in the mammary uptake. For glucose and the milk protein precursors, the reduction in the mammary blood flow explained 60% of the decrease in the mammary uptake, with the other 40% being accounted for by a reduction in the mammary extraction of nutrients. The nutrient uptake was altered as milk yield decreased. These decreases began with the 16-h milking interval and were higher at the 24-h milking interval.

Amino Acids↗

PubMedDate not supplied

Nutrient retention efficiency in streams receiving inputs from wastewater treatment plants.

We tested the effect of nutrient inputs from wastewater treatment plants (WWTPs) on stream nutrient retention efficiency by examining the longitudinal patterns of ammonium, nitrate, and phosphate concentrations downstream of WWTP effluents in 15 streams throughout Catalonia (Spain). We hypothesized that large nutrient loadings would saturate stream communities, lowering nutrient retention efficiency (i.e., nutrient retention relative to nutrient flux) relative to less polluted streams. Longitudinal variation in ambient nutrient concentration reflected the net result of physical, chemical, or biological uptake and release processes. Therefore, gradual increases in nutrient concentration indicate that the stream acts as a net source of nutrients to downstream environments, whereas gradual declines indicate that the stream acts as a net sink. In those streams where gradual declines in nutrient concentration were observed, we calculated the nutrient uptake length as an indicator of the stream nutrient retention efficiency. No significant decline was found in dilution-corrected concentrations of dissolved inorganic nitrogen (DIN) and phosphate in 40 and 45% of streams, respectively. In the remaining streams, uptake length (estimated based on the decline of nutrient concentrations at ambient levels) ranged from 0.14 to 29 km (DIN), and from 0.14 to 14 km (phosphate). Overall, these values are longer (lower retention efficiency) than those from nonpolluted streams of similar size, supporting our hypothesis, and suggest that high nutrient loads affect fluvial ecosystem function. This study demonstrates that the efficiency of stream ecosystems to remove nutrients has limitations because it can be significantly altered by the quantity and quality of the receiving water.

Environmental Monitoring↗

PubMed2004

Molecular and integrative physiology of intestinal peptide transport.

Intestinal protein digestion generates a huge variety and quantity of short chain peptides that are absorbed into intestinal epithelial cells by the PEPT1 transporter in the apical membrane of enterocytes. PEPT1 operates as an electrogenic proton/peptide symporter with the ability to transport essentially every possible di- and tripeptide. Transport is enantio-selective and involves a variable proton-to-substrate stoichiometry for uptake of neutral and mono- or polyvalently charged peptides. Neither free amino acids nor peptides containing four or more amino acids are accepted as substrates. The structural similarity of a variety of drugs with the basic structure of di- or tripeptides explains the transport of aminocephalosporins and aminopenicillins, selected angiotensin-converting inhibitors, and amino acid-conjugated nucleoside-based antiviral agents by PEPT1. The high transport capacity of PEPT1 allows fast and efficient intestinal uptake of the drugs but also of amino acid nitrogen even in states of impaired mucosal functions. Transcriptional and post-transcriptional regulation of PEPT1 occurs in response to alterations in the nutritional status and in disease states, suggesting a prime role of this transporter in amino acid absorption.

Adaptation, Physiological↗

PubMed2025

TaLAC129 is a negative regulator of arbuscular mycorrhizal symbiosis but enhanced the growth and yield of bread wheat.

Arbuscular mycorrhizal (AM) symbiosis enhances nutrient acquisition and stress resilience in plants, yet the genetic mechanisms regulating this interaction in wheat remain poorly understood. This study explores the variation in AM colonization rates across a diverse set of wheat varieties and aims to identify key genes that regulate the wheat-AM symbiosis. Understanding these molecular mechanisms is crucial for improving nutrient uptake efficiency and stress resistance in wheat breeding programs. Here, we conducted a genome-wide association study (GWAS) of 291 wheat varieties and integrated transcriptomic data to identify TaLAC129, a laccase (LAC)-encoding gene, as a critical negative regulator of AM colonization in wheat roots. Overexpression of TaLAC129 significantly increased root LAC activity and lignin content, concurrently suppressing AM colonization. While this suppression reduced nitrogen (N), phosphorus (P), and potassium (K) uptake in stems, leaves, and glumes, it markedly enhanced nutrient utilization efficiency (NUE) in grains. Furthermore, TaLAC129 overexpression improved agronomic traits, including grains per panicle, 1000-grain weight, and overall yield. Our findings reveal the dual role of TaLAC129 in balancing AM symbiosis and nutrient allocation, offering a novel genetic target for breeding wheat varieties with improved yield and nutrient efficiency. This study provides critical insights into the molecular coordination between symbiotic trade-offs and agricultural productivity in cereal crops.

Triticum↗

PubMed1994

Immunolocalization of the Plasma Membrane H+ -ATPase in Minor Veins of Vicia faba in Relation to Phloem Loading.

The immunolocalization of the plasma membrane H+ -ATPase, which generates a proton motive force energizing the uptake of inorganic and organic solutes, was studied by electron microscopy. The cells studied were in minor veins of Vicia faba L. exporting leaves, where photosynthates are supposed to be absorbed from the apoplast by phloem transfer cells. Immunologically detectable H+ -ATPase varied among the different cell types and was considerably denser in the transfer cells than in the other cell types, particularly in the sieve tube. Moreover, the distribution of the H+ -ATPase was not homogeneous in transfer cells, that pump being more concentrated in the region adjacent to the bundle sheath, phloem parenchyma, and xylem vessels than along the smooth part of the wall bordering the sieve tube. These results show that the plasma membrane infoldings of transfer cells possess the proton-pumping machinery required to energize an efficient uptake of photosynthates from the phloem apoplast and an efficient retrieval of nitrogenous compounds from the vascular sap.

Journal Article↗

PubMed2004

Automatic control and remote monitoring system for biological nutrient removal on small wastewater treatment plants in Korea.

Many small-size wastewater treatment plants in Korea's rural communities are designed to remove organic and suspended matter only, and they generally show a large fluctuation in the influent loading compared to municipal wastewater treatment plants (MWWTPs). They also have no professional engineers stationed for efficient operation against mechanical breakdown. For those reasons, the wastewater treatment plants have low efficiency in treatment of nitrogen and phosphorus as well as organic matter. In order to solve those problems, this study developed an automatic control system and RMS (remote monitoring system), which can keep efficiency stable despite any change in the small plants' loading rates and are capable of removing nutrient materials such as nitrogen or phosphorus. According to the results of the Experimental SBR system of the automatic control program, complete nitrification was made under oxic conditions and denitrification occurred as NO3-N concentration decreased by 0.5 mg/l in anoxic conditions and excellent nitrogen removal efficiency was seen generally. The Experimental SBR system created "phosphate release and uptake" effectively and displayed phosphate-removing efficiency up to more than 80% as the concentration of effluent was kept low by 0.4 mg/l. RMS developed in this study transmits a plant's data and operation states to clients in remote locations in real-time interval through the Internet. Therefore, although you are in a remote location, it allows you to see if a plant is properly operated or there is any breakdown.

Automation↗

PubMed2005

Rapid decline in nitrate uptake and respiration with age in fine lateral roots of grape: implications for root efficiency and competitive effectiveness.

Changes in function as an individual root ages has important implications for understanding resource acquisition, competitive ability and optimal lifespan. Both nitrate uptake and respiration rates of differently aged fine roots of grape (Vitis rupestris x V. riparia cv. 3309 C) were measured. The resulting data were then used to simulate nitrate uptake efficiency and nutrient depletion as a function of root age. Both nitrate uptake and root respiration declined remarkably quickly with increasing root age. The decline in both N uptake and root respiration corresponded with a strong decline in root N concentration, suggesting translocation of nitrogen out of the roots. For simulations where no nutrient depletion occurs at the root surface, daily uptake efficiency was maximal at root birth and lifetime nitrate uptake efficiency slowly increased as the roots aged. Simulations of growth of roots into unoccupied soil using a solute transport model indicated the advantage of high uptake capacity in new roots under competitive conditions where nitrate availability is very transitory.

Nitrates↗

PubMed2001

The costing of carbon credits from ocean nourishment plants.

Ocean nourishment is a process for stimulating the sequestration of atmospheric carbon dioxide in the deep ocean by providing the nutrients needed to enhance the production of phytoplankton. The carbon dioxide sink thus created, can be used to generate tradeable carbon credits. The costs of sequestering carbon by the process of ocean nourishment have been estimated using as a basis, the previous experience in nitrogen fixing of Toyo Engineering Corporation. While there are uncertainties about the biological uptake efficiency, these introduce only a moderate uncertainty in our overall estimates of costs. The major determinants of the costs are the interest that must be paid on capital and the cost of the feedstock, natural gas. We have used for discussion purposes, an interest rate of 4-8% per annum and natural gas costs of US$0.5-$2 per GJ. The costs of carbon credits lie in the range US$6.70-$12.40 per tonne of carbon dioxide emissions sequestered. It should be noted that we have adopted the measure of carbon avoided by non-emission, because of the complex partitioning of anthropogenic carbon between the atmosphere, land and ocean.

Animals↗

PubMed1984

[Assays of nutrition in Ascobolus furfuraceus. Sources of nitrogen].

The effect of various nitrogen sources on growth and efficiency parameters of Ascobolus furfuraceus was investigated. As nitrogen sources, sodium nitrate and nitrite, inorganic ammonium salts and nitrated organic compounds have been used. The results showed that all of them could be used by the fungus, with the exceptions of sodium nitrite and ammonium oxalate. Good correlation was observed among the growth parameters, the 'economic coefficients' of uptake and internal conversion of sources, and the specific respiration rates. The best nitrogen source - estimated as growth and efficiency parameters - was ammonium carbonate in the culture conditions used. The possibility of heterotrophic carbon fixation is discussed.

Ascomycota↗

PubMedDate not supplied

Solute clearance in continuous venovenous hemodialysis. A comparison of cuprophane, polyacrylonitrile, and polysulfone membranes.

Critically ill patients with ARF and MOSF were treated with continuous venovenous hemodialysis (CVVHD). The BSM 22 delivery system (CGH Medical, Denver, CO) and four different dialyzer membranes were used. Vascular access was achieved with a dual lumen catheter placed percutaneously into a large vein. Heparin was used for anticoagulation, and commercially available peritoneal dialysis fluid was used as dialysate. At a fixed blood flow rate of 100 ml/min, the dialysate inflow and outflow rates were regulated to control azotemia and fluid balance. Blood side and dialysate side clearances for urea nitrogen, creatinine, bicarbonate, and lactate were measured. All dialyzer membranes studied provided high urea nitrogen clearance approximating dialysate outflow rate and resulting in excellent control of azotemia. Some of the dialyzer membranes also had high creatinine and bicarbonate clearances. Bicarbonate loss was balanced by lactate uptake with all dialyzers. It is concluded that CVVHD is an efficient and safe therapy for acute renal failure, capable of maintaining nitrogen balance in patients with protein catabolic rates up to 2 g/kg/day. Urea nitrogen clearance is dependent upon dialysate outflow rate rather than the dialyzer membrane type or dialyzer flow geometry, and may prove to be the modality of choice for therapy of acute renal failure in unstable patients with MOSF.

Acrylic Resins↗

PubMed2005

Inorganic nitrogen control in wastewater treatment ponds from a fish farm (Orbetello, Italy): denitrification versus Ulva uptake.

The aim of this study was to quantify the N removal efficiency of an Ulva-based phytotreatment system receiving wastewaters from a land-based fish farm (Orbetello, Italy), to identify the main biogeochemical pathways involved and to provide basic guidelines for treatment implementation and management. Fluxes of O2 and nutrients in bare and in Ulva colonised sediments were assessed by light/dark core incubations; denitrification by the isotope pairing technique and Ulva growth by in situ incubation of macroalgal disks in cages. O2 and nutrient budgets were estimated as sum of individual processes and further verified by 24-h investigations of overall inlet and outlet loads. Ulva uptake (up to 7.8 mmol Nm(-2) h(-1)) represented a net sink for water column and regenerated NH4+ whilst N removal via denitrification (10-170 micromol Nm(-2) h(-1)) accounted for a small percentage of inorganic nitrogen load (<5%). Laboratory experiments demonstrated a high potential for denitrification (over 800 microM Nm(-2) h(-1)) indicating that N loss could be enhanced. The control of Ulva standing stocks by optimised harvesting of surplus biomass may represent an effective strategy to maximise DIN removal and could result in the assimilation of approximately 50% of produced inorganic nitrogen.

Analysis of Variance↗

PubMed2005

Carbon availability affects nitrogen source utilisation by Hymenoscyphus ericae.

We compared the ability of five strains of the ericoid mycorrhizal fungus Hymenoscyphus ericae to utilise glutamine, ammonium or nitrate at high or low carbon (C) availability. The pattern of intraspecific variation in growth was affected by C availability. When C supply was high, growth differences between strains were explained by the total amount of nitrogen (N) taken up, suggesting variation in uptake kinetics. Under C-limiting conditions, strain differences were linked with their nitrogen use efficiency, implying intraspecific differences in N metabolism. The relationship between growth on glutamine and pH shifts in the media indicated that there was intraspecific variation in glutamine transporters. In addition, the correlation between pH changes and the amount of glutamine-N recovered as ammonium in the media indicated that there were intraspecific variations within the enzymatic pathways involved in glutamine metabolism. Our findings, compared with those of a previous study involving the same ericoid strains, draw attention to the temporal variation in nitrogen source utilisation by ericoid mycorrhizal fungi when maintained in axenic culture.

Ascomycota↗

PubMed1997

MORE EFFICIENT PLANTS: A Consequence of Rising Atmospheric CO2?

The primary effect of the response of plants to rising atmospheric CO2 (Ca) is to increase resource use efficiency. Elevated Ca reduces stomatal conductance and transpiration and improves water use efficiency, and at the same time it stimulates higher rates of photosynthesis and increases light-use efficiency. Acclimation of photosynthesis during long-term exposure to elevated Ca reduces key enzymes of the photosynthetic carbon reduction cycle, and this increases nutrient use efficiency. Improved soil-water balance, increased carbon uptake in the shade, greater carbon to nitrogen ratio, and reduced nutrient quality for insect and animal grazers are all possibilities that have been observed in field studies of the effects of elevated Ca. These effects have major consequences for agriculture and native ecosystems in a world of rising atmospheric Ca and climate change.

Journal Article↗

PubMed2004

[Effects of nitrogen stress on nutrient uptake by Fraxinus mandshurica seedlings and their biomass distribution].

Under environmental stresses, trees often change their morphological and physiological components to acquire the most limited resources. In northeastern forest region of China, the decomposition and mineralization of litters occur slowly due to low temperature, which often results in forest trees suffering from nutritional stress. With pot culture in greenhouse, this paper studied the effects of nitrogen stress on the physiological and morphological components of Fraxinus mandshurica seedlings. The results showed that under N stress, the net uptake rate of nitrogen and phosphate by the seedlings decreased, while their nitrogen and phosphate use efficiency were higher than those of the seedlings supplied with 8 mmol x L(-1) or 16 mmol x L(-1) of nitrogen during the early growth stage. When suffering from N stress, the leaf mass ratio of the seedlings reduced, with specific leaf area and root mass ratio increased. The relative growth rate increased with the increasing N concentrations supplied to the seedlings during the whole growth period. Under N stress, the net assimilation rate decreased, which resulted in the decrease of total biomass, and the root/shoot ratio was significantly higher than that of the seedlings supplied with 8 mmol x L(-1) or 16 mmol x L(-1) of nitrogen during the early growth stage. There was no significant difference during the late growth stage.

Biomass↗

PubMed2006

Potential mineralization of nitrogen from organic wastes to ryegrass and wheat crops.

Two-pot experiments with ryegrass and wheat plants were conducted in a Cambic Arenosol to test the reliability of N fate predicted by incubation experiments previously performed, with the same soil, to assess potentially mineralizable nitrogen from six organic wastes (municipal solid waste compost, secondary pulp mill sludge, horn meal, poultry manure, solid phase from pig slurry and composted pig manure). Two treatments, corresponding to 80 and 160 kgN/ha were tested, with or without mineral N fertilization. Experimental data obtained in the pot trials was consistent with nitrogen net mineralization trend observed in the aerobic incubations with all the wastes tested. Values of potentially mineralizable nitrogen (N(0)) from the equations obtained by model fitting, to the incubation data, were well correlated to ryegrass and wheat N uptake. Poultry manure was the most efficient N supplier to crops.

Crops, Agricultural↗

PubMed1995

Identification and characterization of two nitrogen-regulated genes of the cyanobacterium Synechococcus sp. strain PCC7942 required for maximum efficiency of nitrogen assimilation.

Two nitrogen-regulated genes were found in the genomic DNA region upstream of the nirA operon involved in uptake and utilization of nitrate in Synechococcus sp. strain PCC7942. The two genes (nirB and ntcB) are transcribed divergently from nirA and encode proteins of 349 and 309 amino acid residues, respectively. The levels of nirB and ntcB transcripts were low in cells growing on ammonium and increased upon transfer of ammonium-grown cells to nitrate-containing medium. The deduced NirB protein sequence has no similarities to other known proteins, whereas the deduced NtcB protein sequence is homologous to bacterial transcriptional activators of the LysR family. Defined mutants constructed by interrupting nirB or ntcB with a drug resistance marker grew as fast as the wild-type strain on ammonium but grew slower than the wild-type strain on nitrate or nitrite. The nirB mutant had higher activities of nitrate reductase, glutamine synthetase, and glutamate synthase than the wild-type strain, but its nitrite reductase activity was 40% of the wild-type levels. The mutant excreted nitrite into the medium during growth on nitrate, showing that nitrite reductase limits nitrate assimilation. These findings suggested that nirB is required for expression of maximum nitrite reductase activity. When grown on ammonium, the nirB mutant grew normally but cultures of the ntcB mutant still showed a yellowish-green color typical of nitrogen-limited cells. NtcB seems to regulate utilization of fixed nitrogen by controlling the expression of a certain gene(s) involved in nitrogen metabolism.

Amino Acid Sequence↗

PubMed2002

Performance of an age series of Alnus-cardamom plantations in the Sikkim Himalaya: nutrient dynamics.

Nutrient cycling, nutrient use efficiency and nitrogen fixation in an age series of Alnus-cardamom plantations were studied in the eastern Himalaya. The impact of stand age (5, 10, 15, 20, 30 and 40 years) on the nutrient dynamics of mixtures of N2-fixing (Alnus nepalensis) and non-N2-fixing (large cardamom) plants was assessed. Foliar nutrient concentrations of Alnus decreased with advancing age groups of plantations and showed an inverse relationship with stand age. Annual N fixation increased from the 5-year-old stand (52 kg ha(-1)), peaking in the 15-year-old stand (155 kg ha(-1)) and then decreased with increasing plantation age. Nitrogen and phosphorus uptake was lowest in the 40-year-old stand, and highest in the 15- and 5-year-old stand, respectively. Nutrient storage in understorey cardamom was very high: up to 31 % N and 59 % P of the stand total in the 15-year-old stand. Nutrient use efficiency was higher (with faster turnover times) in younger stands and decreased (with slower turnover times) in older plantations. Nitrogen retranslocation showed a strong positive relationship with stand age, while that of P was inversely related to stand age. Nutrient standing stock, uptake and return were also highest in the 15-year-old stand. Nitrogen and P cycling in Alnus-cardamom plantations was functionally balanced. Nutrient cycling and dynamics indicated that Alnus-cardamom plantations performed sustainably up to 15-20 years. The management practice should be altered to incorporate replantation after this age.

Algorithms↗