0305-7364/0 * For corre bcgn.grignon. There is still disagreement about whether crop growth rate or soil nitrate concentration control nitrogen absorption by crops under ®eld conditions. The in ̄uence of these factors on the control of N uptake rate was examined in the absence of water stress, using data on dry matter production, above-ground nitrogen accumulation and soil nitrate concentration ...

[1] Waliguan Observatory (WO) is a land-based Global AtmosphereWatch baseline station on the Tibetan Plateau. Size-resolved ionic aerosols (NH4 , Na, K, Ca, Mg, SO4 2 , Cl , NO3 CO3 2 , formate, acetate and oxalate), organic aerosols, black carbon and gaseous HNO3 and SO2 were measured during an intensive fall-winter field experiment. The observational data were analyzed with a focus on the par...

Nitrate can serve as a terminal electron acceptor in place of carbon dioxide and inhibit methane emission in the rumen and nitrate reducing bacteria might help enhance the reduction of nitrate/nitrite, which depends on the type of feed offered to animals. In this study the effects of three levels of sodium nitrate (0, 5, 10 mM) on fermentation of three diets varying in their wheat straw to conc...

This article discusses how nitrate assimilation is integrated with nitrate uptake, with ammonium assimilation and amino acid synthesis, with pH regulation, and with the sugar supply in tobacco leaves. During the first part of the light period, nitrate assimilation exceeds nitrate uptake by 2-fold and ammonium assimilation by 50%, leading to rapid depletion of nitrate and accumulation of ammoniu...

Nitrate and certain short chain nitrocompounds and nitro-oxy compounds are being investigated as dietary supplements to reduce economic and environmental costs associated with ruminal methane emissions. Thermodynamically, nitrate is a preferred electron acceptor in the rumen that consumes electrons at the expense of methanogenesis during dissimilatory reduction to an intermediate, nitrite, whic...

It is possible by means of repeated injections of uranium nitrate to produce in the cat a subacute or chronic nephritis which can progress to a fatal termination and show in its course increasing accumulation of non-protein nitrogen in the blood. This nephritis differs only slightly from the spontaneous chronic nephritis of the species. Repeated doses of diphtheria toxin produce a subacute form...

A large reservoir of bioavailable nitrogen (up to approximately 10(4) kilograms of nitrogen per hectare, as nitrate) has been previously overlooked in studies of global nitrogen distribution. The reservoir has been accumulating in subsoil zones of arid regions throughout the Holocene. Consideration of the subsoil reservoir raises estimates of vadose-zone nitrogen inventories by 14 to 71% for wa...

Severely Ca-deficient Triticum aestivum L. seedlings accumulated high levels of nitrite and moderate levels of nitrate and organic nitrogen, but contained unaltered levels of hydroxylamine. Nitrite accumulation was not related to molybdenum deficiency, or altered cellular pH. Nitrate reductase was decreased by Ca deficiency, apparently by repression of enzyme synthesis from accumulated nitrite ...

In sugar beet seedling period and sugar accumulation period, the quantity of NR-mRNA raised with the rate of nitrate nitrogen and ammonium nitrogen raised, and the activity of NR raised also, that was the quantity of NR-mRNA of NO3/NH4 —4:0 was the highest. In phyllome formation period and root growth period, the quantity of NR-mRNA of NO3/NH4—3:1 was the highest, and its activity was the highe...

The enrichment of denitrifying phosphate accumulating organisms (DNPAOs) is the prerequisite for the denitrifying phosphate removal process. This study investigated the effect of nitrate concentration on the enrichment of DNPAOs was studied with batch experiments. The Sequencing Batch Reactor (SBR) was set-up with acetate as the sole carbon source. The addition of nitrate solution and the anoxi...