Physiological responses of three northern conifers to rapid and slow induction of moisture stress

1985 ◽  
Vol 63 (7) ◽  
pp. 1171-1176 ◽  
Author(s):  
G. F. Buxton ◽  
D. R. Cyr ◽  
E. B. Dumbroff ◽  
D. P. Webb
Keyword(s):  
Polyethylene Glycol ◽  
Osmotic Potential ◽  
White Spruce ◽  
Moisture Stress ◽  
Jack Pine ◽  
Soil Drying ◽  
Mild Stress ◽  
Pressure Potential ◽  
Polyethylene Glycol 400 ◽  
Drought Period

The response of black and white spruce and jack pine to slow and rapid induction of moisture stress was evaluated during soil drying and exposure to liquid cultures containing polyethylene glycol 8000. Marked changes in water, osmotic, and pressure potentials were observed in all three species, but water potentials were the most sensitive indicators of moisture stress. Osmotic potentials were sensitive to mild stress in polyethylene glycol (−400 kPa), but they held relatively steady at higher stress intensities (−800 to −1600 kPa). Large decreases in osmotic potential were recorded in white spruce and jack pine during severe drying stress late in the drought period and these changes were accompanied by large decrements in water and pressure potentials. Significant changes in osmotic potential were not observed in black spruce prior to seedling death. Losses in pressure potential were only observed at −1600 kPa of polyethylene glycol stress, although wilting in young tissue was apparent at lower stress intensities. Pressure potentials of plants in the soil-drying test fell well below those recorded in the polyethylene glycol study. The highest resistance to loss of turgor and the maximum adjustment to moisture stress were observed in white spruce. Shoot growth and transpiration declined in the three conifers at relatively low stress intensities. Total chlorophyll and the chlorophyll stability index decreased during drought, but the differences recorded among species were not clearly related to observed differences in drought tolerance. Cation concentrations did not change during stress.

Effect of osmotic potential on synthesis and secretion of polygalacturonase and cellulase by Geotrichum candidum

1987 ◽  
Vol 33 (2) ◽  
pp. 138-141 ◽  
Author(s):  
L. L. Davis ◽  
A. B. A. M. Baudoin
Keyword(s):  
Polyethylene Glycol ◽  
Osmotic Potential ◽  
Geotrichum Candidum ◽  
Major Effect ◽  
Minor Effect ◽  
Polyethylene Glycol 400 ◽  
Liquid Cultures ◽  
A Minor ◽  
Osmotic Potentials

In liquid cultures of Geotrichum candidum, amended with KCl, mannitol, or polyethylene glycol 400 to control osmotic potential, levels of both intracellular and extracellular endopolygalacturonase fell off rapidly with decreasing osmotic potential in the range of −0.5 to −2.5 MPa. Concentrations (units per millilitre) of intracellular endopolygalacturonase were higher than those of extracellular endopolygalacturonase at all osmotic potentials tested. The ratio of intracellular to extracellular endopolygalacturonase concentration increased with decreasing osmotic potential; this became most pronounced below −1.5 MPa. It appeared that the major effect of osmotic potential was on endopolygalacturonase synthesis with a minor effect on endopolygalacturonase secretion from the cell. Levels of intracellular and extracellular cellulase also decreased with decreasing osmotic potential, although the effect was much smaller than with endopolygalacturonase. However, the ratio of intracellular to extracellular cellulase concentration did not change significantly with changes in osmotic potential. This indicated that only the synthesis of cellulase was affected.

Development, Evaluation and Optimization of Osmotic Controlled Tablets of Aceclofenac for Rheumatoid Arthritis Management

2019 ◽  
Vol 9 (1) ◽  
pp. 29-36
Author(s):  
Bijaya Ghosh ◽  
Niraj Mishra ◽  
Preeta Bose ◽  
Moumita D. Kirtania
Keyword(s):  
Rheumatoid Arthritis ◽  
Polyethylene Glycol ◽  
Sodium Chloride ◽  
Cellulose Acetate ◽  
Hydroxypropyl Methylcellulose ◽  
Release Profile ◽  
Polyethylene Glycol 400 ◽  
Permeable Membrane ◽  
Cumulative Release ◽  
The Core

Objective: Rheumatoid arthritis is a dreaded disease, characterized by pain, inflammation and stiffness of joints, leading to severe immobility problems. The disease shows circadian variation and usually gets aggravated in early morning hours. Aceclofenac, a BCS Class II compound is routinely used in the treatment of pain and inflammation associated with rheumatoid arthritis. The objective of this study was to develop an osmotic delivery system of Aceclofenac that after administration at bedtime would deliver the drug in the morning hours. </P><P> Methods: A series of osmotically controlled systems of aceclofenac was developed by using lactose, sodium chloride and hydroxypropyl methylcellulose K100M as osmogens. Cellulose acetate (2% w/v in acetone) with varying concentrations of polyethylene glycol-400 was used as the coating polymer to create semi permeable membrane and dissolution was carried out in 290 mOsm phosphate buffer. Formulation optimization was done from four considerations: cumulative release at the end of 6 hours (lag time), cumulative release at the end of 7 hours (burst time), steady state release rate and completeness of drug release. </P><P> Results: A formulation having swelling polymer hydroxypropyl methylcellulose in the core and lactose and sodium chloride as osmogens, polyethylene glycol-400 (16.39 %) as pore former, with a coating weight of 5% was a close fit to the target release profile and was chosen as the optimum formulation. Conclusion: Aceclofenac tablets containing lactose, HPMC and sodium chloride in the core, given a coating of cellulose acetate and PEG-400 (5% wt gain), generated a release profile for optimum management of rheumatoid arthritic pain.

The effect of humidity, root excision, and potassium supply on hypocotyl elongation in dark-grown seedlings of Helianthus annuus

1984 ◽  
Vol 62 (3) ◽  
pp. 420-428 ◽  
Author(s):  
Gordon I. McIntyre ◽  
John S. Boyer
Keyword(s):  
Helianthus Annuus ◽  
Osmotic Potential ◽  
Stem Elongation ◽  
Growth Responses ◽  
Pressure Potential ◽  
Cell Turgor ◽  
Low Humidity ◽  
Potassium Supply ◽  
Root Excision ◽  
Growing Region

When seedlings of Helianthus annuus L. were grown in the dark with their roots in vermiculite saturated with distilled water the rate of elongation of the hypocotyl was significantly increased by increasing the relative humidity around the shoot from approximately 25 to 100%. This response was correlated with a reduction in transpiration rate of approximately 95% and with increases in the water potential and cell turgor in the growing region. Measurements with a transducer revealed very rapid growth responses to changes in humidity, usually preceded by a variable period of growth oscillations. Excision of the roots, either in water or in air, induced an immediate increase in rate of elongation at low humidity, but at high humidity this response was delayed and markedly reduced. The growth rate was significantly increased by supplying 10 mM KCl to the roots at both high and low humidity. The response to K was slower than the response to humidity and was correlated with a significant reduction in the osmotic potential of the growing region. A growth response was first detected approximately 45 min after the application of K to the roots and 10 min after application to the shoot. These results arc consistent with the hypothesis that, in the intact plant, stem elongation is largely controlled by the interacting effects on cell turgor of transpiration-induced negative pressure potential in the apoplast and the osmotic potential of the growing cells.

Eco-friendly polyethylene glycol-400: a rapid and efficient recyclable reaction medium for the synthesis of thiazole derivatives

2010 ◽  
Vol 3 (3) ◽  
pp. 205-208 ◽  
Author(s):  
Bhaskar S. Dawane ◽  
Baseer M. Shaikh ◽  
Namdev T. Khandare ◽  
Vinod T. Kamble ◽  
Santosh S. Chobe ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
Reaction Medium ◽  
Thiazole Derivatives ◽  
Polyethylene Glycol 400

Development of Aqueous Formulation Containing the Extracted Mangiferin

2021 ◽  
Vol 901 ◽  
pp. 40-47
Author(s):  
Chanikanda Tessiri ◽  
Sunee Channarong ◽  
Paveena Wongtrakul
Keyword(s):  
Polyethylene Glycol ◽  
Mangifera Indica ◽  
Aqueous Solubility ◽  
Extraction Yield ◽  
Primary Sources ◽  
Polyethylene Glycol 400 ◽  
Pure Solvent ◽  
Aging Properties ◽  
Dipropylene Glycol ◽  
Log Linear

Mangiferin, a polyphenol of C-glycosylxanthone, exhibits various bioactivities with poor aqueous solubility. It is known as a potent antioxidant, which leads to remarkable UV protection and anti-aging properties. Mangiferin can be found in many plant species, among which the mango leaf is one of the primary sources. From our study, the extraction yield of mangifein obtained from the leaves of Mangifera indica L. variety Nam Doc Mai was 3.17% with 95.02% ± 0.064 purity (HPTLC analysis). The solubility of mangiferin in the studied pure solvents arranging in descending order were ethoxydiglycol, dimethyl isosorbide, polyethylene glycol 400, polyethylene glycol 600, propylene glycol, dipropylene glycol, glycerin, isopentyldiol, methanol, ethanol and water, whereas the addition of the solvent in water could increase the aqueous solubility of mangiferin. In several cases, the solubility was apparently higher than that dissolved in its pure solvent state. The log-linear solubility model for the cosolvent system was used to calculate the volume fractions of the selected solvents needed to solubilize mangiferin content at the twenty times of the IC50 against DPPH radicals. In conclusion, the developed aqueous formulation contained 0.5% w/v of mangiferin and 20% w/v of polyethylene glycol 600 or dipropylene glycol as a solubilizer in water.

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