Potassium nitrate

About: Potassium nitrate is a research topic. Over the lifetime, 3537 publications have been published within this topic receiving 29450 citations. The topic is also known as: Nitric acid, potassium salt & Saltpeter.

Effects of anaerobic conditions on water and solute relations, and on active transport in roots of maize (Zea mays L.)

Abstract: The effects of anoxia on water and solute transport across excised roots of young maize plants (Zea mays L. cv. Tanker) grown hydroponically have been studied. With the aid of the root pressure probe, root pressure (Pr), root hydraulic conductivity (Lpr), and root permeability (Psr), and reflection (σ sr) coefficients were measured using potassium nitrate (a typical nutrient salt) and sodium nitrate (an atypical nutrient salt) as solutes. During a period of 10–15 h, anaerobic treatment (0.0–0.2 g O2·m-3 in root medium) caused a decrease of root pressure by 0.01–0.28 MPa (by 10–80% of original root pressure) after a short transient increase. For a time period of 5 h, the decrease in the stationary root pressure was not reversible. Under anaerobic conditions, roots still behaved like osmometers and were not leaky. The root hydraulic conductivity measured in osmotic experiments (osmotic solute: NaNO3) was smaller by one to two orders of magnitude than that measured in the presence of hydrostatic gradients. Both the osmotic and hydrostatic hydraulic conductivity decreased during anaerobic treatment by 28 and 44%, respectively, at a constant reflection coefficient of the solutes (σ sr=0.3−1.0). As with root pressure, changes in root permeability to water and solutes were not reversible within 5 h. Under aerobic conditions and at low external concentrations (31–59 mOsmol·kg-1), osmotic response curves were monophasic for KNO3, i.e. there was no passive uptake of solutes. Response curves became biphasic at higher concentrations (100–150 mOsmol·kg-1)- For NaNO3, response curves were biphasic at all concentrations. Presumably, this pattern was a consequence of the fact that potassium had already accumulated in the xylem. During anoxia, accumulation of potassium in the xylem was reduced, and biphasic responses were also obtained at lower potassium concentrations applied to the medium. The results are discussed in terms of a pump/leak model of the root in which anoxia affects both the active ion pumping and the permeability of the root to nutrient salts (leakage). The effects of anaerobiosis on the passive transport properties of the root (Lpr, Psr, σ sr) are in line with the recently proposed ‘composite transport model of the root’.

Effect of nitrogen and carbon sources on the inorganic phosphate solubilization by different aspergillus niger strains

Abstract: The Mineral phosphate solubilization (MPS) was studied in ten Aspergillus niger strains. MPS activity was measured in solid (Pikovskaya's medium) as well as liquid media using different phosphate sources (tricalcium, dicalcium, ferric and aluminium phosphates, and bone meal), carbon sources (glucose, mannitol, fructose, sucrose, xylose, and sorbitol), and nitrogen sources (ammonium sulfate, ammonium chloride, ammonium nitrate, sodium nitrate, potassium nitrate, and urea). All the strains showed a zone of clearance of tricalcium phosphate in Pikovskaya's medium in plates and solubilized dicalcium and tricalcium phosphates in broth efficiently. Solubilization was lower in ferric and aluminium phosphates. The activity was very poor in bone meal medium. Among the carbon sources the fungi preferred mannitol for higher P solubilization. Nitrogen in the form of nitrate was very effective in solubilizing inorganic phosphates. Xylose and urea were the poorest sources of carbon and nitrogen for all the strains of A...

Calcium Hydroxide and Potassium Nitrate as Desensitizing Agents for Hypersensitive Root Surfaces

Abstract: The purpose of this investigation was to evaluate calcium hydroxide and potassium nitrate individually as densensitizing agents for hypersensitive root surfaces. The apparatus used in the experiment to measure hypersensitivity was (a) a thermo-electric stimulating device to measure hot and cold stimulation quantitatively and (b) a mechanical stimulating device to measure scratch stimulation quantitatively. The conclusions drawn from the study were: 1. Calcium hydroxide was more consistently effective in decreasing sensitivity then was potassium nitrate or the control. 2. Calcium hydroxide as compared to the control was statistically (99% level of significance) more effective in reducing sensitivity to mechanical, hot and cold stimulation immediately and at the conclusion of the experiment (3 months). 3. It appears that calcium hydroxide could be used as a desensitizing agent initially following periodontal surgery to reduce pain from hypersensitive roots in order that proper oral hygiene could be reestablished.

A New Method of Potassium Chromate Production from Chromite and KOH-KNO3-H2O Binary Submolten Salt System

Abstract: A new method of chromate production by applying a new reaction system of KOH-KNO3-H2O (binary submolten salt system) is proposed and proved feasible. Under conditions of temperature 350 degrees C, KOH-to-chromite ore ratio 2:1, stirring speed 700 rpm, KNO3-to-chromite ore ratio 0.8:1, oxygen partial pressure 50%, and gas flow 1 L/min, chromium conversion ratio obtained is >98% with reaction time around 300 min. The decomposition of chromite ore in the system is a typical process of solid-liquid-gas reaction, which is coordinately controlled by mass diffusion in product layer and interface reaction. Apparent activation energy of decomposition in the temperature range from 280 to 370 degrees C is 55.63 kJ/mol. During reaction, oxygen dissolves into KOH-KNO3-H2O melt system first and some cluster, e.g. O-2(2-), is formed and the mass diffusion 2 coefficient of the cluster was calculated. The system can be considered as both a media of oxygen transportation and reactant donator. Potassium nitrate plays a role of catalyst in the oxidation decomposition reaction of chromite ore and potassium hydroxide. (C) 2009 American Institute of Chemical Engineers AIChE J, 55: 2646-2656, 2009