scholarly journals Osmotic Adjustment by Intact Isolated Chloroplasts in Response to Osmotic Stress and Its Effect on Photosynthesis and Chloroplast Volume

1985 ◽  
Vol 79 (4) ◽  
pp. 996-1002 ◽  
Author(s):  
Simon P. Robinson
Keyword(s):  
Osmotic Stress ◽  
Osmotic Adjustment ◽  
Chloroplast Volume ◽  
Isolated Chloroplasts

Accumulation of Glycinebetaine in Chloroplasts Provides Osmotic Adjustment During Salt Stress

1986 ◽  
Vol 13 (5) ◽  
pp. 659 ◽  
Author(s):  
SP Robinson ◽  
GP Jones
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Salt Stress ◽  
Osmotic Adjustment ◽  
Osmotic Potential ◽  
Spinacia Oleracea ◽  
Resonance Spectroscopy ◽  
Leaf Osmotic Potential ◽  
Cellular Compartments ◽  
Isolated Chloroplasts

Glycinebetaine was determined in leaves and in isolated chloroplasts of spinach (Spinacia oleracea) by nuclear magnetic resonance spectroscopy. Some leakage of glycinebetaine from the chloroplasts occurred during the isolation so the concentration in chloroplasts in vivo could be up to 1.5 times higher than that measured in isolated chloroplasts. It was demonstrated that any contamination of the chloroplast preparations by glycinebetaine originating from other cellular compartments or from broken chloroplasts would have amounted to less than 10% of the measured values. Leaf osmotic potential of salt-stressed plants was -2.09 MPa compared to -0.91 MPa in non-stressed controls. This was accompanied by a sixfold increase in glycinebetaine content in the leaf but the levels of choline and proline were not increased. In chloroplasts isolated from control leaves the calculated glycinebetaine concentration was 26 mM which was 10-fold higher than the concentration in the leaf as a whole but only contributed 7% of the osmotic potential of the chloroplast. Chloroplasts from salt-stressed plants contained up to 300 mM glycinebetaine which was 20 times the concentration in the leaf as a whole. The glycinebetaine concentration in chloroplasts from salt-stressed leaves was equivalent to an osmotic potential of -0.75 MPa and this contributed 36% of the osmotic potential of the chloroplast and 64% of the decrease in osmotic potential induced by salt stress. At least 30-40% of the total leaf glycinebetaine was localized in the chloroplast. The results demonstrate that glycinebetaine accumulates in chloroplasts to provide osmotic adjustment during salt stress and provide support for the hypothesis that glycinebetaine is a compatible cytoplasmic solute which may be preferentially located in the cytoplasm of cells.

Photosynthesis of isolated chloroplasts and protoplasts under osmotic stress

Planta ◽  
1981 ◽  
Vol 151 (4) ◽  
pp. 375-380 ◽  
Author(s):  
Werner M. Kaiser ◽  
Wolfgang Stepper ◽  
Wolfgang Urbach
Keyword(s):  
Osmotic Stress ◽  
Isolated Chloroplasts

Resveratrol Alleviates the KCl Salinity Stress of Malus hupenensis Rhed. Seedlings by Regulating K+/Na+ Homeostasis, Osmotic Adjustment, and Reactive Oxygen Species Scavenging

2021 ◽  
Author(s):  
Tingting Li ◽  
Yuqi Li ◽  
Zhijuan Sun ◽  
Xiangli Xi ◽  
Guangli Sha ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Osmotic Stress ◽  
Salinity Stress ◽  
Osmotic Adjustment ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Apple Rootstock ◽  
Physiological Mechanisms ◽  
Species Production ◽  
Apple Quality

Abstract Background: Applying large amounts of potash fertilizer in apple orchards for high apple quality and yield aggravates KCl stress. As a phytoalexin, resveratrol (Res) participates in plant resistance to biotic stress. However, its role in relation to KCl stress have never been reported. Results: Malus hupenensis is a widely used apple rootstock in China and is sensitive to KCl stress. In this study, 100 µmol Res was exogenously applied to alleviate KCl stress in M. hupenensis seedlings. The seedlings treated with Res had higher chlorophyll content and photosynthetic index than those without Res treatment. Moreover, the molecular and physiological mechanisms of Res in ion toxicity, osmotic stress, and oxidative damage induced by KCl stress were also investigated. First, exogenous Res affects K+/Na+ homeostasis in cytoplasm by enhancing K+ efflux outside the cells, inhibiting Na+ efflux and K+ absorption, and compartmentalizing K+ into vacuoles. Second, this compound could respond to osmotic stress by regulating the accumulation of proline. Lastly, this polyphenol functions as an antioxidant that strengthens the activities of POD and CAT thus eliminates the reactive oxygen species production induced by KCl stress.Conclusions: Taken together, these results reveal that resveratrol alleviates the KCl salinity stress of M. hupenensis seedlings by regulating K+/Na+ homeostasis, osmotic adjustment, and reactive oxygen species scavenging.

scholarly journals The role of osmotic adjustment, cell production and sugar accumulation for the root growth under the osmotic stress condition.

Root Research ◽  
2007 ◽  
Vol 16 (2) ◽  
pp. 47-58
Author(s):  
Atsushi Ogawa ◽  
Choji Kawashima ◽  
Kinji Kitamichi ◽  
Kyoko Toyofuku ◽  
Akira Yamauchi
Keyword(s):  
Osmotic Stress ◽  
Root Growth ◽  
Osmotic Adjustment ◽  
Stress Condition ◽  
Sugar Accumulation ◽  
Cell Production

The Effect of Plant Size on Wheat Response to Agents of Drought Stress. II. Water Deficit, Heat and ABA

1997 ◽  
Vol 24 (1) ◽  
pp. 43 ◽  
Author(s):  
A. Blum ◽  
C. Y. Sullivan ◽  
H. T. Nguyen
Keyword(s):  
Growth Rate ◽  
Heat Stress ◽  
Drought Stress ◽  
Osmotic Stress ◽  
Osmotic Adjustment ◽  
Plant Size ◽  
Shoot Biomass ◽  
Growth Reduction ◽  
Potential Growth ◽  
Juvenile Plants

Plant size has long been implicated in plant response to drought stress. This study is the second in a series of two intended to examine the effect of plant size on plant performance under the effect of various agents of drought stress. Variable plant size (in terms of plant height and shoot biomass) independent of genetic background effects was experimentally achieved using rht (tallest), Rht1 and Rht2 (medium) and Rht3 (shortest) homozygous height isogenic lines of spring wheat (Triticum aestivum) cultivars Bersee and April-Bearded. Plants were grown in hydroponic culture in the growth chamber. In the first experiment, juvenile plants were challenged by osmotic stress using polyethylene glycol (PEG) in the nutrient solution giving a water potential of –0.55 MPa. The control nutrient solution was at –0.05 MPa. Plant growth, shoot biomass, leaf area, relative water content (RWC) and osmotic adjustment (OA) were measured. In the second experiment, effects on growth rate of chronic heat stress and abscisic acid (ABA) in the root medium of juvenile plants were evaluated. Potential plant size as determined by shoot biomass in the controls at 25 days after emergence was greatest in rht, medium in Rht1 and Rht2, and smallest in Rht3 genotypes. Potential growth rate and leaf area were greater in plants of larger potential biomass (rht) than in plants of smaller potential biomass (Rht3). Growth reduction by osmotic stress was inversely related to plant size, while the extent of osmotic adjustment during osmotic stress was directly related to plant size. RWC did not vary with plant size. Relative growth reduction by heat stress and by ABA also decreased in smaller plants. ABA did not alleviate the depressing effect of heat on growth. Despite the greater stress tolerance of smaller (Rht3) plants, the absolute growth and biomass of large (rht) plants under stress conditions was always better than that of smaller plants. The results of these series of experiments suggest that greater stress tolerance of small plants is derived from their relatively smaller size and slower growth rate. Consequently, we conclude that growth under stress is sustained by potential growth rate and plant size of the genotype when stress is mild and by plant tolerance (even at the expense of potential growth rate and size) when stress is more severe.

OSMOTIC ADJUSTMENT OF CELL SAP TO INCREASES IN ROOT MEDIUM OSMOTIC STRESS

Soil Science ◽  
1963 ◽  
Vol 96 (5) ◽  
pp. 326-330 ◽  
Author(s):  
ROBERT H. RUF ◽  
RICHARD E. ECKERT ◽  
RICHARD O. GIFFORD
Keyword(s):  
Osmotic Stress ◽  
Osmotic Adjustment ◽  
Root Medium
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