The identification of nitrate-nitrogen (NO3–N) origin is important in the control of surface and ground water quality. These are the main sources of available drinking water. Stable isotopes (15N and 18O) for NO3–N and along with a 1-D reactive transport model were used to study the origin and processes that lead to nitrogen transformation and loss in a major stream that flows into a reservoir ...

The Root Zone Water Quality Model (RZWQM, V 3.25) was used to simulate the effect of swine manure applications on nitrate-nitrogen (NO3-N) concentrations in subsurface drain water from continuous corn for Iowa soils. Measured values of subsurface drain flow, NO3-N concentrations in drainage water, and residual NO3-N in the soil profile from three chisel plow plots were available for the growing...

The importance of storm frequency as well as the groundwater and hyporheic inputs on nitrate (NO3-N) and ammonium (NH4-N) levels in stream water were studied in a small perennial Mediterranean catchment, Riera Major, in northeast Spain. NO3-N concentrations ranged from 0.15 to 1.9 mg l-1. Discharge explained 47% of the annual NO3-N concentration variance, but this percentage increased to 97% wh...

[1] Patterns of DOC and nitrate (NO3 ) concentrations and fluxes were studied for six storm events across four forested, glaciated, subcatchments (1.6 to 696 ha) in western New York, USA. End-member mixing analysis (EMMA) showed that catchment runoff was composed of shallow groundwater (SGW) discharged at seeps and throughfall (THF) on the rising limb and THF and riparian water (RW) on the rece...

A combination of ground water modeling, chemical and dissolved gas analyses, and chlorofluorocarbon age dating of water was used to determine the relation between changes in agricultural practices, and NO3- concentrations in ground water of a glacial outwash aquifer in west-central Minnesota. The results revealed a redox zonation throughout the saturated zone with oxygen reduction occurring nea...

The effects of intracellular Cl- concentration ([Cl-]i) on acetylcholine (ACh)-stimulated exocytosis were studied in guinea pig antral mucous cells by video microscopy. ACh activated Ca2+-regulated exocytosis (an initial phase followed by a sustained phase). Bumetanide (20 microM) or a Cl- -free (NO3-) solution enhanced it; in contrast, 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB, a Cl- c...

As a vital beverage crop, tea has been extensively planted in tropical and subtropical regions. Nitrogen (N) levels and forms are closely related to tea quality. Based on different N levels and forms, we studied changes in NO3- and NH4+ fluxes in tea roots utilizing scanning ion-selective electrode technique. Our results showed that under both single and mixed N forms, influx rates of NO3- were...

In most aerobic soils, nitrate (NO3(-)) is the main nitrogen source for plants and is often limiting for plant growth and development. To adapt to a changing environment, plants have developed complex regulatory mechanisms that involve short and long-range signalling pathways in response to both NO3(-) availability in the soil and other physiological processes like growth or nitrogen (N) and ca...

Luminescent pentanuclear tetra-decker Ln(III) complexes [Eu5L4(OH)2(NO3)4(H2O)2].NO3.3H2O , [Nd5L4(OH)2(NO3)5MeOH].3MeOH.2H2O and [Eu5L4(CF3SO3)4(MeO)2(H2O)4].CF3SO3.H2O are formed from Ln(NO3)3.6H2O (Ln = Eu (1), Nd (2)) and Eu(CF3SO3)3, respectively (H2L = N,N'-bis(5-bromo-3-methoxysalicylidene)phenylene-1,2-diamine).

The effect of NO3- uptake on cellular pH was studied in maize roots by an in vivo 31P-NMR technique. In order to separate the effects on cytoplasmic pH due to NO3- uptake from those due to NO3- reduction, tungstate was used to inhibit nitrate reductase (NR). The results confirm that in maize roots tungstate inhibited NR activity. 15N-NMR in vivo experiments demonstrated the cessation of nitroge...