Effect of Moisture Stress on Germination and Radicle Development ofPinuseldarica Medw. and Pinusponderosa Laws.

1975 ◽  
Vol 5 (1) ◽  
pp. 80-83 ◽  
Author(s):  
Karim Djavanshir ◽  
C. P. P. Reid
Keyword(s):  
Polyethylene Glycol ◽  
Water Potential ◽  
Marked Reduction ◽  
Seedling Survival ◽  
Moisture Stress ◽  
Percentage Germination ◽  
Radicle Growth ◽  
Peg 4000 ◽  
Effect Of Moisture ◽  
Germination Value

Polyethylene glycol (PEG-4000) was used to study the effect of substrate water potential, ranging from 0 to 20 negative bars, on the germination of Pinusponderosa and P. eldarica seeds over a 35 day period. A marked reduction in percentage germination and germination value (GV) occurred at −4 bars for P. ponderosa and −6 bars for P. eldarica and optimum germination occurred at −2 and −4 bars, respectively. The best radicle growth (elongation) occurred at −2 bars for both species, but was severely reduced at potentials −4 bars or less. Although germination occurred at potentials as low as −8 bars for P. ponderosa and −12 bars for P. eldarica, it was estimated that percentage seedling survival would be near zero at these moisture stresses because of a marked reduction in radicle growth.

The growth of selected mycorrhizal fungi in response to induced water stress

1973 ◽  
Vol 51 (9) ◽  
pp. 1579-1588 ◽  
Author(s):  
John Mexal ◽  
C. P. P. Reid
Keyword(s):  
Water Potential ◽  
Mycorrhizal Fungi ◽  
Maximum Growth ◽  
Moisture Stress ◽  
Thelephora Terrestris ◽  
Soil Moisture Stress ◽  
Suillus Luteus ◽  
Peg 4000 ◽  
The Media ◽  
Cenococcum Graniforme

Three ectomycorrhizal fungi, Cenococcwn graniforme, Suillus luteus, and Thelephora terrestris were grown in artificial nutrient media. Water potential of the media was varied by the use of the osmoticum polyethylene glycol (PEG) 4000 and measured by thermocouple psychrometry. Cenococcum graniforme was very tolerant of low water potentials and exhibited maximum growth at a potential of −15 bars. Maximum growth of S. luteus and T. terrestris occurred at −5 bars. The water potential of solutions containing PEG 4000 appears to consist of both an osmotic and matric component, making PEG 4000 ideally suited for simulation of soil moisture stress. It was neither metabolized nor readily absorbed by C. graniforme as inorganic salts or sugars might be.

scholarly journals Seed Priming Effect on Symbiotic Germination and Seedling Development of Orchis palustris Jacq.

HortScience ◽  
2004 ◽  
Vol 39 (7) ◽  
pp. 1700-1701 ◽  
Author(s):  
Ahmet Esitken ◽  
Sezai Ercisli ◽  
Cafer Eken ◽  
David Tay
Keyword(s):  
Polyethylene Glycol ◽  
Water Potential ◽  
Priming Effect ◽  
Mycorrhizal Fungus ◽  
Seed Priming ◽  
Germination Percentage ◽  
Seedling Development ◽  
Percentage Germination ◽  
Oatmeal Agar ◽  
Symbiotic Germination

Seeds of Orchis palustris Jacq. were primed for 1- to 5-day in polyethylene glycol (PEG-6000) solutions at -0.5, -1.0 or -1.5 MPa. The seeds were symbiotically germinated with BNR 8-3 mycorrhizal fungus on oatmeal agar at 22 °C. In general, priming hastened rapid germination. At -1.5 MPa water potential, the first to germinate was eight days compared to 18 days for the control. Percentage germination increased as priming water potential decreased, and the percentage germination was 55%, 58%, and 65%, at -0.5, -1.0, and -1.5 MPa, respectively, versus 43% for the nonprimed control. Priming duration from 1 to 5 days had little effect on germination performance. The best germination percentage (68%) was obtained from 1 day at -1.5 MPa treatment.

The effect of moisture stress upon the hatching of Nematodirus battus larvae

Parasitology ◽  
1975 ◽  
Vol 70 (2) ◽  
pp. 149-155 ◽  
Author(s):  
J. T. Parkin
Keyword(s):  
Soil Moisture ◽  
Polyethylene Glycol ◽  
Osmotic Pressure ◽  
Moisture Stress ◽  
Soil Moisture Stress ◽  
Egg Hatching ◽  
Effect Of Moisture

An experiment was carried out to investigate the effect of soil moisture stress upon the hatching behaviour of Nematodirus battus. The method involved the use of polyethylene glycol solutions to maintain a steady osmotic pressure around a soil containing N. battus eggs, which were ready to hatch. Different concentrations of polyethylene glycol (creating different moisture stresses) were found to affect the numbers and the rate of egg hatching markedly.

scholarly journals The Influence of Temperature and Viscosity of Polyethylene Glycol on the Rate of Microwave-Induced In Situ Amorphization of Celecoxib

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 110
Author(s):  
Nele-Johanna Hempel ◽  
Tra Dao ◽  
Matthias M. Knopp ◽  
Ragna Berthelsen ◽  
Korbinian Löbmann
Keyword(s):  
Polyethylene Glycol ◽  
Microwave Radiation ◽  
Magnesium Stearate ◽  
Einstein Equations ◽  
Dissolution Process ◽  
Target Temperature ◽  
Peg 4000 ◽  
Lower Viscosity ◽  
Model Drug

Microwaved-induced in situ amorphization of a drug in a polymer has been suggested to follow a dissolution process, with the drug dissolving into the mobile polymer at temperatures above the glass transition temperature (Tg) of the polymer. Thus, based on the Noyes–Whitney and the Stoke–Einstein equations, the temperature and the viscosity are expected to directly impact the rate and degree of drug amorphization. By investigating two different viscosity grades of polyethylene glycol (PEG), i.e., PEG 3000 and PEG 4000, and controlling the temperature of the microwave oven, it was possible to study the influence of both, temperature and viscosity, on the in situ amorphization of the model drug celecoxib (CCX) during exposure to microwave radiation. In this study, compacts containing 30 wt% CCX, 69 wt% PEG 3000 or PEG 4000 and 1 wt% lubricant (magnesium stearate) were exposed to microwave radiation at (i) a target temperature, or (ii) a target viscosity. It was found that at the target temperature, compacts containing PEG 3000 displayed a faster rate of amorphization as compared to compacts containing PEG 4000, due to the lower viscosity of PEG 3000 compared to PEG 4000. Furthermore, at the target viscosity, which was achieved by setting different temperatures for compacts containing PEG 3000 and PEG 4000, respectively, the compacts containing PEG 3000 displayed a slower rate of amorphization, due to a lower target temperature, than compacts containing PEG 4000. In conclusion, with lower viscosity of the polymer, at temperatures above its Tg, and with higher temperatures, both increasing the diffusion coefficient of the drug into the polymer, the rate of amorphization was increased allowing a faster in situ amorphization during exposure to microwave radiation. Hereby, the theory that the microwave-induced in situ amorphization process can be described as a dissolution process of the drug into the polymer, at temperatures above the Tg, is further strengthened.

Effect of Moisture Stress on Seed Growth in Soybeans 1

1984 ◽  
Vol 76 (4) ◽  
pp. 647-650 ◽  
Author(s):  
L. Meckel ◽  
D. B. Egli ◽  
R. E. Phillips ◽  
D. Radcliffe ◽  
J. E. Leggett
Keyword(s):  
Moisture Stress ◽  
Seed Growth ◽  
Effect Of Moisture
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