The effect of three osmotic agents on free proline and amino acid pools in Atriplex canescens and Hilaria jamesii

1987 ◽  
Vol 65 (4) ◽  
pp. 799-801 ◽  
Author(s):  
William A. Cress ◽  
Gordon V. Johnson

Three commonly used osmotic agents, mannitol, sucrose, and polyethylene glycol 4000, were used to simulate water stress in two arid region plant species, Hilaria jamesii (Torr.) Benth. and Atriplex canescens (Pursh) Nutt. Large amounts of mannitol (300–1400 μmol/g dry wt.) and sucrose (450–660 μmol/g dry wt.) were absorbed by both plant species, while insignificant amounts of polyethylene glycol 4000 were absorbed. During osmotic stress, Hilaria jamesii accumulated large quantities of proline, while A. canescens accumulated only a small amount. Shoot proline content of both species varied significantly with the osmotic agents used to simulate water stress. These results indicate that use of absorbable osmotic agents to simulate water stress may have important metabolic effects on the concentration of free proline and other metabolites.

1983 ◽  
Vol 13 (2) ◽  
pp. 334-338 ◽  
Author(s):  
Paul J. Schulte ◽  
Paul E. Marshall

Some responses of very young jack pine (Pinusbanksiana Lamb.), red pine (Pinusresinosa Ait.), and black locust (Robiniapseudoacacia L.) seedlings grown under constant water stress conditions induced by polyethylene glycol 4000 culture solutions were investigated. Seedlings grown under stressful conditions had lower leaf conductance, produced less foliar surface area, and accumulated less dry weight than nonstressed seedlings. Seedlings grown under nonstressed conditions were found to undergo considerable transpiration at night. When compared with the pines, black locust seedlings grew more rapidly, had lower (more negative) xylem pressure potentials, and showed poorer survival under the more stressful growth conditions.


2020 ◽  
Vol 6 (2) ◽  
pp. 50
Author(s):  
SUKARMAN SUKARMAN ◽  
I. DARWATI ◽  
D. RUSMiN

<p><strong>Morphological and physiological characteristics of Vinca at di fferent water stress levels</strong></p><p>Vinca (Vinca rosea L.) is one of the important medicinal crops as the sources of raw materials for traditional medicines. Its alkaloid is believed can reduce the risk of cancer, blood tension and diabetes diseases. Recently, vinca is only grown as ornamental plant in the garden, therefore, its cultivation methods is limited, especially its water stress tolerance, lite purpose of this experiment was to study the effect of water stess on the morphological and physiological characteristics of vinca. A pot experiment was conducted in the plastics house of the Research Institute for Spice and Medicinal Crops from November 1997 to March 1998. Factorial experiment consisted two factors and three replications was arranged in a randomized block design. Ihe irst factor consisted of two vinca varieties, those wee white flowers (WFV) and red flowers of vinca (RFV). While 4 different levels of water stress i.e., (I) 100% ield capacity (FC), (2) 80% FC, (3) 60% FC, and (4) 40% FC were used as the second factor. Parameters used for evaluating the effect of teatment consisted of morphological characteristics such as (I) plant height, (2) number of primary branches, (3) number of leaves, (4) leaf area (5) dry weight of stem, (6) dry weight of leaf, (7) dry weight of flowers and (8) dry weight of roots, and physiological characteristics observed including: (I) percentages of opened stomata and (2) free proline content of leaf. Results showed that interaction between varieties and water stress did not significantly affect the morphological nor physiological characteristics. Varieties significantly affected the morphological characteristics (except plant height), however they did not signiicantly affect physiological characteristics. Water stress significantly affected the morphological (except dry weight of roots) and free proline contents. Under 80% FC, vinca produced the highest growth and dry weight of plant however, the plant growth and dry weight wee inhibited under 60 and 40% FC. Under 40% FC, percentages of opened stomata deceased signiicantly. Moeover, proline content in the leaves signiicantly increased by water stess treatments.</p>


2013 ◽  
Vol 36 (1-2) ◽  
pp. 59-65 ◽  
Author(s):  
Hanna Chełkowska ◽  
Danuta Zielińska

Rapid accumulation of free proline was found in barley leaves under conditions of osmotic stress at the level of -8.3 bars, but not before 9 days of its duration. The threshold value of osmotic stress for the start of a rapid accumulation of proline was about -6 bars. The excised leaves of barley subjected to water stress by wilting accumulated free proline more rapidly. In the course of 24 hours free proline content increased about 30-fold, while the water content in the leaves decreased 3-fold only. We found also that excised barley leaves with full turgor treated with abscisic acid (10<sup>-4</sup> M) accumulated free proline as early as after 3 hours and subsequently after 24 hours free proline content increased 10-fold.


Author(s):  
Fernando H. B. Machado ◽  
Andréia M. S. de S. David ◽  
Lucas V. S. Cangussú ◽  
Josiane C. Figueiredo ◽  
Hugo T. R. Amaro

ABSTRACT Water stress is a condition that causes physiological changes in different species and even genotypes of the same species. One of the osmotic agents most used to simulate this condition is polyethylene glycol 6000. The aim of this study was to evaluate the effects of water stress on the physiological quality of seeds and performance of seedlings of crambe genotypes. A completely randomized design was used, in a factorial scheme with two genotypes (one cultivar and one line) and five osmotic potentials simulated with aqueous solutions of polyethylene glycol 6000 (control = 0, -0.25, -0.50, -1.0, -1.50 MPa), with four replicates of 50 seeds per treatment. The effects of the treatments were evaluated by means of germination, first count, germination speed index and fresh and dry matter of seedlings. The physiological quality of seeds and the performance of crambe seedlings are negatively affected under water stress from -0.25 MPa on. Seeds of the genotype FMSCR 1101 have greater tolerance to drought stress, regardless of the osmotic potential used.


Author(s):  
Hatice Tunca ◽  
Ali Doğru ◽  
Feray Köçkar ◽  
Burçin Önem ◽  
Tuğba Ongun Sevindik

Azadirachtin (Aza) used as insecticide due to inhibiting growth of insects and preventing them from feeding on plants. To understand the effects of contamination of this insecticide on phototrophs, and to determine the responses of these organisms against these insecticides are extremely important in understanding how the ecosystem is affected. In this study, chlorophyll-a amount, OD 560 and antioxidant parameters (total SOD, APX, GR, Proline, MDA and H2O2) were determined in order to understand the effect of Aza on Arthrospira platensis Gomont. Aza was applied between 0–20 μg mL−1 concentrations for 7 days in the study. Enzyme analysis was conducted at the end of the 7th day. There was a statistically significant decrease in the absorbance of OD560 and the chlorophyll-a content in A. platensis cultures exposed to the Aza (0–20 μg mL−1) during 7 days due to the increase in pesticide levels. SOD activity decreased at 8, 16 and 20 μg mL−1 concentrations; GR enzyme activity showed a significant decrease compared to the control at a concentration of 20 μg mL−1. APX activity did not change significantly compared to control. The MDA content increased significantly at 16 and 20 μg mL−1 concentrations. The H2O2 content significantly increased at 12, 16 and 20 μg mL−1 concentrations (p < 0.05) while the free proline content decreased at 4 μg mL−1 concentration (p < 0.05). As a result, regarding the Aza concentrations used in this study may be a step to prevent pesticide pollution in the environment.


2013 ◽  
Vol 50 (3) ◽  
pp. 407-425 ◽  
Author(s):  
T. SAMPATHKUMAR ◽  
B. J. PANDIAN ◽  
P. JEYAKUMAR ◽  
P. MANICKASUNDARAM

SUMMARYWater stress induces some physiological changes in plants and has cumulative effects on crop growth and yield. Field experiments were conducted to study the effect of deficit irrigation (DI) on yield and some physiological parameters in cotton and maize in a sequential cropping system. Creation of soil moisture gradient is indispensable to explore the beneficial effects of partial root zone drying (PRD) irrigation and it could be possible only through alternate deficit irrigation (ADI) practice in paired row system of drip layout that is commonly practiced in India. In the present study, PRD and DI concepts (creation of soil moisture gradient) were implemented through ADI at two levels of irrigation using drip system. Maize was sown after cotton under no till condition without disturbing the raised bed and drip layout. Relative leaf water content (RLWC) and chlorophyll stability index (CSI) of cotton and maize were reduced under water stress. A higher level of leaf proline content was observed under severe water-stressed treatments in cotton and maize. RLWC and CSI were highest and leaf proline content was lowest in mild water deficit (ADI at 100% crop evapotranspiration once in three days) irrigation in cotton and maize. The same treatments registered higher values for crop yields, net income and benefit cost ratio for both the crops.


Author(s):  
Rana Obaidat ◽  
Bashar Al-taani ◽  
Hanan Al-quraan

Objective: Meloxicam is classified as class II corresponding to its high permeability and low solubility (12μg/ml). This study aims to compare the effect of selected polymers on stabilization of amorphous form, and dissolution of meloxicam by preparation of different solid dispersions using selected polymers (chitosan oligomers, polyvinylpyrrolidone K30, and polyethylene glycols).Methods: These solid dispersions were prepared using two different methods; solvent evaporation method for the two molecular weights chitosan carriers (16 and 11KDa) and polyvinylpyrrolidone-K30 and melting method for the two different molecular weights polyethylene glycol (4000 and 6000). The physicochemical properties of solid dispersions were analyzed using differential scanning calorimetry, Fourier transform infra-red analysis, Powder X-ray diffraction, and scanning electron microscopy. Selected dispersions were then compared to two selected marketed drugs (Mobic® and Moven®).Results: Best dissolution rates were obtained for both polyvinylpyrrolidone-K30 and polyethylene glycol 6000, followed by chitosan 16 kDa, chitosan 11 kDa, and polyethylene glycol 4000. Increasing polymeric ratio increased dissolution rate except for chitosan. Precipitation of the drug as amorphous form occurred in chitosan and polyvinylpyrrolidone-K30 dispersions, while no change in crystallinity obtained for polyethylene glycol dispersions. Failure of polyvinylpyrrolidone-K30 in the maintenance of stability during storage time was observed while re-crystallization occurred in chitosan-based dispersions, which ends with preferences to polyethylene glycol dispersions. After comparing the release of selected dispersions with the two selected polymers; all dispersions got a higher release than that of the two marketed drugs release.Conclusion: The dissolution profile of meloxicam has been increased successfully in a reproducible manner.


2021 ◽  
Vol 5 (2) ◽  
pp. 64-72
Author(s):  
Danesha Seth Carley ◽  
Lauren A Gragg ◽  
Matthew J Matthew ◽  
Thomas W Rufty

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