Potassium nitrate

About: Potassium nitrate is a(n) research topic. Over the lifetime, 3537 publication(s) have been published within this topic receiving 29450 citation(s). The topic is also known as: Nitric acid, potassium salt & Saltpeter.

Chemical synthesis of nitric oxide in the stomach from dietary nitrate in humans.

Abstract: BACKGROUND/AIMS: It has been suggested that dietary nitrate, after concentration in the saliva and reduction to nitrite by tongue surface bacteria, is chemically reduced to nitric oxide (NO) in the acidic conditions of the stomach. This study aimed to quantify this in humans. METHODS: Ten healthy fasting volunteers were studied twice, after oral administration of 2 mmol of potassium nitrate or potassium chloride. Plasma, salivary and gastric nitrate, salivary and gastric nitrite, and gastric headspace NO concentrations were measured over six hours. RESULTS: On the control day the parameters measured varied little from basal values. Gastric nitrate concentration was 105.3 (13) mumol/l (mean (SEM), plasma nitrate concentration was 17.9 (2.4) mumol/l, salivary nitrate concentration 92.6 (31.6) mumol/l, and nitrite concentration 53.9 (22.8) mumol/l. Gastric nitrite concentrations were minimal (< 1 mumol/l). Gastric headspace gas NO concentration was 16.4 (5.8) parts per million (ppm). After nitrate ingestion, gastric nitrate peaked at 20 minutes at 3430 (832) mumol/l, plasma nitrate at 134 (7.2) mumol/l, salivary nitrate at 1516.7 (280.5) mumol/l, and salivary nitrite at 761.5 (187.7) mumol/l after 20-40 minutes. Gastric nitrite concentrations tended to be low, variable, and any rise was non-sustained. Gastric NO concentrations rose considerably from 14.8 (3.1) ppm to 89.4 (28.6) ppm (p < 0.0001) after 60 minutes. All parameters remained increased significantly for the duration of the study. CONCLUSIONS: A very large and sustained increase in chemically derived gastric NO concentrations after an oral nitrate load was shown, which may be important both in host defence against swallowed pathogens and in gastric physiology.

Relative humidity-temperature relationships of some saturated salt solutions in the temperature range 0 degree to 50 degrees C

Abstract: The relative humidity-temperature relationships have been determined in air in equilibrium with saturated salt solutions of lithium chloride. LiCl. H 2 O; magnesium chloride, MgCl 2 . 6H 2 O; sodium dichromate, Na 2 Cr 2 O 7 .2H 2 O; magnesium nitrate, Mg(NO 3 ) 2 . 6H 2 O; sodium chloride, NaCl; ammonium sulfate, (NH 4 ) 2 SO 4 ; potassium nitrate, KNO 3 ; and potassium sulfate, K 2 SO 4 , over a temperature range of 0° to 50°C, using the dewpoint method. The relative humidity is a continuous function of temperature, and, except for sodium chloride, is monotonic. The curve for sodium chloride increases from 74. 9 percent relative humidity at 0°C to a maximum of 75.6 percent at 30°C and then gradually decreases to 74.7 percent. The maximum change in relative humidity with temperature, about 15 percent relative humidity as the temperature increases from 0° to 50°C, occurs with saturated salt solutions of sodium dichromate and magnesium nitrate.

Microbial immobilization of ammonium and nitrate in cultivated soils

Abstract: The microbial immobilization of ammonium and nitrate was measured by 13 N organic measurements after the application of labelled urea, (NH 4 ) 2 SO 4 , KNO 3 (KN) or NH 4 NO 3 with or without glucose in four different soils. In the soils incubated without glucose, the microbial immobilization of the added ammonium varied between 1.5 and 4 mg N kg −1 soil. No immobilization occurred at the expense of NO 3 when KN was applied. When glucose was added at the rate 500 mg C kg −1 soil, the immobilization was very active between the first and the third day, at 10°C. The maximal amounts of 13 N immobilized were much higher for the [ 15 N]urea, 15 (NH 4 ) 2 SO 4 , 15 NH 4 NO 3 and 15 NO 3 K. treatments than for the NH 4 15 NO 3 application. This preferential immobilization of NH 4 was also observed in pure cultures of bacteria isolated from one of the soils and attributed to the inhibition of nitrate uptake by ammonium. The immobilization ratio, immobilized N: decomposed C, was calculated for glucose, accounting for pool substitution effects and immobilization due to native C. It was independent of the form of N applied and similar between soils, c 45–48 mg N g −1 C.

Limited feeding of potassium nitrate for intracellular lipid and triglyceride accumulation of Nannochloris sp. UTEX LB1999.

Abstract: Limited feeding of nitrate during culture of Nannochloris sp. UTEX LB1999 for intracellular lipid and triglyceride accumulation was investigated with the aim of obtaining cells superior for liquefaction into a fuel oil. The intracellular lipid contents and the percentage of triglycerides in the lipids of cells grown in a nitrogen-limited medium (0.9 mM KNO3) were 1.3 times as high as those grown in a modified NORO medium containing 2.0–9.9 mM KNO3. However, the cell concentration was too low for the practical production of fuel oil by high-pressure liquefaction of the cell mass. A single feeding of 0.9 mM nitrate after nitrate depletion during cultivation in a nitrate-limited medium increased the cell concentration to twice that obtained without such feeding, and the lipid content was maintained at a high level. The timing of nitrate feeding, i.e., whether it was given during the log phase (before nitrate depletion), the constant growth phase (just after the depletion), or the stationary phase (after the depletion), had negligible effect on the intracellular lipid content and percentage of triglycerides in the lipids. When 0.9 mM nitrate was intermittently fed ten times during the log phase in addition to the initial nitrate feed (0.9 mM), the cell concentration reached almost the same (2.16 g/l) and the intracellular lipid content and the percentage of triglycerides in the lipids increased from 31.0 to 50.9% and 26.0 to 47.6%, respectively, compared with those of cells cultured in a modified NORO medium containing 9.9 mM KNO3 without additional nitrate feeding.

Improved salt tolerance of melon (Cucumis melo L.) by the addition of proline and potassium nitrate

Abstract: A pot experiment was carried out under glasshouse conditions with melon ( Cucumis melo ) cv. “Tempo F1” in a mixture of peat, perlite and sand (1:1:1) to investigate the effects of external proline and potassium nitrate applications to salinity-treated (150 mM) plants with respect to fruit yield, plant growth, some physiological parameters and ion uptake. Treatments were—(i) control (C): plants receiving nutrient solution, (ii) salinity treatment, as for control plus 150 mM NaCl. Salinity treatment was combined with or without either 5 mM supplementary KNO 3 or 10 mM proline. The salt treatment (150 mM NaCl) led to significant decreases in plant growth, fruit yield, relative water content (RWC), stomatal density, uptake of Ca 2+ , K + and N, and chlorophyll a and b contents, accompanied by significant increases in Na + uptake, proline concentration and membrane permeability. Supplementary KNO 3 and proline treatments significantly ameliorated the adverse effects of salinity on plant growth, fruit yield and the physiological parameters examined. This could be attributed to the effects of all the external supplements in maintaining membrane permeability, and increasing concentrations of Ca 2+ , N and K + in the leaves of plants subjected to salt stress.