Seasonal and clonal variations in drought tolerance of Populusdeltoides

1991 ◽  
Vol 21 (6) ◽  
pp. 910-916 ◽  
Author(s):  
G. Michael Gebre ◽  
Michael R. Kuhns
Keyword(s):  
Drought Tolerance ◽  
Osmotic Potential ◽  
Weight Fraction ◽  
Dry Weight ◽  
Weather Conditions ◽  
Injury Index ◽  
Eastern Cottonwood ◽  
Leaf Osmotic Potential ◽  
Favorable Weather ◽  
Osmotic Potentials

Water relations of three field-grown eastern cottonwood (Populusdeltoides Bartr.) clones were compared for the 1989 growing season. Clonal and seasonal variations in leaf water potential, leaf osmotic potential, dry weight fraction, and injury index were measured. The injury index was calculated from conductivity changes due to electrolyte leakage during rehydration of dehydrated and nondehydrated leaves. When samples were measured after dry periods, dry weight fraction increased and injury index and predawn osmotic potential declined. There were significant negative correlations between dry weight fraction and osmotic potential for all clones. There were no significant differences between clones from Nebraska (Platte) and Indiana (Tippecanoe) throughout the season in osmotic potential and injury index. The clones Platte and Tippecanoe had significantly lower osmotic potentials than a clone from Ohio (Ohio Red) on most sample dates. When injury index values increased following favorable weather conditions, Platte and Tippecanoe had a significantly lower injury index than Ohio Red. Since all clones had lower osmotic potential, higher dry weight fraction, and lower injury index during dry periods, it was concluded that all had drought hardened during the period, indicating that all clones have some degree of drought tolerance.

scholarly journals Impact of Temperature, Osmotic Potential, and Osmoregulant on the Growth of Three Ectotrophic Root-Infecting Fungi of Kentucky Bluegrass

Plant Disease ◽  
1997 ◽  
Vol 81 (8) ◽  
pp. 873-879 ◽  
Author(s):  
Karen A. Plumley ◽  
Ann B. Gould ◽  
Bruce B. Clarke
Keyword(s):  
Osmotic Potential ◽  
Agar Medium ◽  
Fungal Growth ◽  
Dry Weight ◽  
Kentucky Bluegrass ◽  
Magnaporthe Poae ◽  
Daily Rate ◽  
Solid Agar ◽  
Leptosphaeria Korrae ◽  
Osmotic Potentials

Two isolates each of Magnaporthe poae, Gaeumannomyces incrustans, and Leptosphaeria korrae were grown at 25°C in liquid shake culture in minimal salts medium (-0.12 MPa) or minimal salts medium adjusted to -0.5 MPa with KCl, MgCl2, or polyethylene glycol (PEG). Fungal dry weight of all three species was greater in minimal salts medium amended to -0.5 MPa with MgCl2 than in nonamended medium, and dry weight in medium amended with PEG was not different from dry weights in nonamended medium or medium amended with KCl. Fungi were incubated at varying temperatures on a minimal salts solid-agar medium (-0.12 MPa) adjusted to osmotic potentials ranging from -0.5 to -5.0 MPa with KCl or MgCl2. Optimum growth of M. poae, G. incrustans, and L. korrae on nonamended medium occurred at 30, 30, and 25°C, respectively. At optimum temperatures for each species, fungal growth was greatest at the higher osmotic potentials tested (-0.5 to -1.0 MPa) and decreased in a linear manner as osmotic potential decreased. In most cases, growth was detected at the lowest osmotic potential measured (-5.0 MPa). The relationship of fungal growth to osmotic potential depended on both temperature and osmoregulant. At temperatures optimal or nearly optimal for fungal development, the growth of all three fungi declined more rapidly with decreasing osmotic potential when grown on medium amended with MgCl2 than on medium amended with KCl. At the highest temperature evaluated for growth of M. poae and L. korrae (35 and 30°C, respectively), growth on medium amended with KCl was curvilinear and peaked at osmotic potentials of -2.5 to -3.0 MPa. Furthermore, between osmotic potentials of -2.0 and -5.0 MPa, M. poae grew best at 35°C. When maintained on nonamended minimal salts medium (-0.12 MPa) in liquid culture at 25°C or on nonamended solid-agar medium at temperatures optimal for growth, M. poae grew at a faster daily rate than L. korrae.

Osmotic Adjustment in Expanding and Fully Expanded Leaves of Sunflower in Response to Water Deficits

1980 ◽  
Vol 7 (2) ◽  
pp. 181 ◽  
Author(s):  
MM Jones ◽  
NC Turner
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Osmotic Adjustment ◽  
Osmotic Potential ◽  
Leaf Water ◽  
Similar Degree ◽  
Tissue Water ◽  
Predawn Leaf Water Potential ◽  
Leaf Osmotic Potential ◽  
Osmotic Potentials

Sunflower plants were grown in large volumes of soil and slowly water-stressed by withholding water. The tissue water relationships of leaves at various stages of stress and of leaves of equivalent well watered controls were studied by the pressure chamber technique. Plants were stressed either when leaf 17 was expanding or when it was fully expanded. When expanding leaves reached a moderate level of stress (predawn leaf water potential of -0.9 MPa), the osmotic potentials at full turgor and zero turgor were lower than the control values by 0.1 MPa and 0.2 MPa, respectively. When fully expanded leaves were stressed to a similar degree (predawn leaf water potential of - 1.1 MPa), the osmotic potentials at full turgor and zero turgor were lower than the control values by 0.2 MPa and 0.3 MPa, respectively. The development of more severe stress in the fully expanded leaves was not accompanied by any further osmotic adjustment. However, when the expanding leaves reached a predawn leaf water potential of -2.3 MPa, the values of leaf osmotic potential at full turgor and zero turgor were lower than the values for the well watered plants by 0.4 MPa and 0.6 MPa, respectively. In expanding leaves prestressed to a predawn leaf water potential of -2.3 MPa, the osmotic potential at full turgor was significantly less than the control values for at least 7 days after rewatering. Stress had no effect on the bulk modulus of elasticity. It is concluded that both expanding and fully expanded sunflower leaves show osmotic adjustment.

scholarly journals 405 Glycinebetaine Accumulation in Red Beet under Salinity

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 513E-513
Author(s):  
Guntur V. Subbarao ◽  
Raymond M. Wheeler ◽  
L.H. Levine ◽  
Gary W. Stutte
Keyword(s):  
Osmotic Adjustment ◽  
Osmotic Potential ◽  
Dry Weight ◽  
Hydroponic System ◽  
Red Beet ◽  
Leaf Osmotic Potential ◽  
Sodium Toxicity ◽  
Relative Water ◽  
The Mean ◽  
External Salinity

Accumulation of glycinebetaine occurs in Chenopodiaceae members and is thought to assist in osmotic adjustment and protect cytoplasm from sodium toxicity. Red beet has an ability to tolerate high tissue sodium levels, which may result in increased glycinebetaine production. To test this hypothesis, two cultivars of red beet ['Scarlet Supreme' (SS) and `Ruby Queen' (RQ)] were grown under nonsaline (4.75 mM Na) and saline (54.75 mM Na) conditions in a recirculating hydroponic system for 42 days at elevated CO2 (1200 μmol•mol-1) in a growth chamber. Leaf glycinebetaine level, relative water content, and osmotic potential were measured at weekly intervals. Leaf glycinebetaine levels increased with plant age and reached a maximum of 67 μmol•g-1 dw under nonsaline and 101 μmol•g-1 dry weight (dw) under saline conditions at 42 days in SS; in RQ, the glycinebetaine levels reached a maximum of 91 μmol•g-1 dw under nonsaline and 121 μmol•g-1 dw under saline conditions by 26 days. The mean glycinebetaine levels were increased over two-thirds under saline conditions in both the cultivars. RQ accumulated significantly higher (37% more under nonsaline, and 46% more under salinity) glycinebetaine than SS. The turgid leaf osmotic potential of RQ was consistently higher than SS under nonsaline (2.23 MPa in RQ vs. 1.82 MPa in SS) and saline (2.48 MPa in RQ vs. 2.02 MPa in SS) conditions. The results indicate that higher glycinebetaine levels in the leaf could result in better osmotic adjustment, and glycinebetaine accumulation in red beet can vary among cultivars and is strongly affected by external salinity.

Response of sunflower (Helianthus annuus L) genotypes to PEG-mediated water stress

2014 ◽  
Vol 9 (12) ◽  
pp. 1206-1214
Author(s):  
Roumiana Vassilevska-Ivanova ◽  
Lydia Shtereva ◽  
Boris Kraptchev ◽  
Tanya Karceva
Keyword(s):  
Drought Tolerance ◽  
Osmotic Stress ◽  
Helianthus Annuus ◽  
Growth Parameters ◽  
Dry Weight ◽  
Germination Percentage ◽  
Helianthus Annuus L ◽  
Shoot Dry Weight ◽  
Four Levels ◽  
Osmotic Potentials

AbstractDrought tolerance of two sunflower (Helianthus annuus L.) genotypes, cultivated cultivar 1114 and interspecific line H. annuus × H. mollis, was studied under laboratory conditions using PEG-6000. Four levels of osmotic stress (−0.4, −0.6, −0.8 and −1.0 MPa) were created and performances were monitored against a control. Physiological and biochemical stress determining parameters such as malondialdechyde (MDA), proline content, and hydrogen peroxide (H2O2) were compared between seedlings of both genotypes. The results indicated that both genotypes have similar responses at four osmotic potentials for all traits studied. All seedling growth parameters such as germination percentage, root length, shoot length, root and shoot dry weight decreased with increasing osmotic stress. MDA, proline, and H2O2 were found to be increased at different osmotic gradients in comparison to control. Cultivar 1114 was less affected than the interspecific line under these stress conditions. The data observed in the experiments revealed that perennial wild H. mollis can hardly be considered to be an excellent candidate of drought tolerance genes.

Specific leaf metabolic changes that underlie adjustment of osmotic potential in response to drought by four Quercus species

2020 ◽  
Author(s):  
Ismael Aranda ◽  
Estrella Cadahía ◽  
Brígida Fernández de Simón
Keyword(s):  
Drought Tolerance ◽  
Osmotic Adjustment ◽  
Osmotic Potential ◽  
Quinic Acid ◽  
Molecular Processes ◽  
Leaf Habit ◽  
Leaf Osmotic Potential ◽  
Quercus Species ◽  
Metabolic Basis ◽  
Watering Treatment

Abstract Osmotic adjustment is almost ubiquitous as a mechanism of response to drought in many forest species. Recognized as an important mechanism of increasing turgor under water stress, the metabolic basis for osmotic adjustment has been described in only a few species. We established an experiment with four species of the genus Quercus ranked according to drought tolerance and leaf habit from evergreen to broad-leaved deciduous. A cycle of watering deprivation was imposed on seedlings, resulting in well-watered (WW) and water-stressed (WS) treatments, and their water relations were assessed from pressure-volume (P-V) curves. Leaf predawn water potential (Ψpd) significantly decreased in WS seedlings which was followed by a drop in leaf osmotic potential at full turgor (Ψπ100). The lowest values of Ψπ100 followed the ranking of decreasing drought tolerance: Q. ilex < Q. faginea < Q. pyrenaica < Q. petraea. The leaf osmotic potential at the turgor loss point (ΨTLP) followed the same pattern as Ψπ100 across species and treatments. The pool of carbohydrates, some organic acids, and cyclitols were the main osmolytes explaining osmotic potential across species, likewise to the osmotic adjustment assessed from the decrease in leaf Ψπ100 between WW and WS seedlings. Amino-acids were very responsive to WS, particularly γ-aminobutyric acid (GABA) in Q. pyrenaica, but made a relatively minor contribution to osmotic potential compared with other groups of compounds. In contrast, the cyclitol proto-quercitol made a prominent contribution to the changes in osmotic potential regardless of watering treatment or species. However, different metabolites such as quinic acid, played a more important role in osmotic adjustment in Q. ilex, distinguishing it from the other species studied. In conclusion, while osmotic adjustment was present in all four Quercus species, the molecular processes underpinning this response differed according to their phylogenetic history and specific ecology.

The effect of a water stress on the cold hardiness of winter wheat

1981 ◽  
Vol 59 (9) ◽  
pp. 1717-1721 ◽  
Author(s):  
N. J. Tyler ◽  
L. V. Gusta ◽  
D. B. Fowler
Keyword(s):  
Water Stress ◽  
Moisture Content ◽  
Winter Wheat ◽  
Osmotic Potential ◽  
Cold Hardiness ◽  
Sugar Content ◽  
Dry Weight ◽  
Total Sugar Content ◽  
Stress Studies ◽  
Leaf Osmotic Potential

Crowns of winter wheat plants water stressed with polyethylene glycol (PEG) (molecular weight 20 000) prior to hardening were more cold hardy than tender crowns or crowns hardened for 2 days (p ≤ 0.05). After 16 days of hardening, plants from all treatments reached the same level of hardiness. Winter wheat crowns water stressed with PEG (210 g/L) for either 0,5, or 21 days reached the same level of hardiness after 2 days of acclimation. In both short- and long-term stress studies, the crown moisture content of the stressed plants was lower (p ≤ 0.05) than that of the controls prior to acclimation. With increasing hardiness both leaf osmotic potential and crown moisture content decreased (p ≤ 0.05). Short-term water stress also resulted in an increase in sugars, specifically sucrose (p ≤ 0.05) prior to cold hardening. However the total sugar content did not parallel the increase in hardiness.Changes in several metabolic parameters were also considered. Significant correlations were found in both studies between the LT50 and osmotic potential, moisture content, and dry weight. Most of the variability in LT50 could be explained by changes in leaf osmotic potential and crown moisture content.

scholarly journals Relative Salt Tolerance of Five Herbaceous Perennials

HortScience ◽  
2006 ◽  
Vol 41 (6) ◽  
pp. 1493-1497 ◽  
Author(s):  
Genhua Niu ◽  
Denise S. Rodriguez
Keyword(s):  
Salt Tolerance ◽  
Osmotic Potential ◽  
Tap Water ◽  
Visual Quality ◽  
Dry Weight ◽  
Salinity Treatment ◽  
Herbaceous Perennials ◽  
Elevated Salinity ◽  
Leaf Osmotic Potential ◽  
Salinity Levels

Use of recycled water to irrigate urban landscapes may be inevitable, because the freshwater supply has been diminishing and the population continues to grow in the arid and semiarid southwestern United States. However, little information exists on the performance of landscape plants irrigated with nonpotable water. Two greenhouse studies were conducted during the summer and the fall to characterize the relative salt tolerance of five herbaceous perennials by irrigating the plants with a saline solution at an electrical conductivity (EC) of 0.8 dS·m–1 (tap water), 2.0 dS·m–1, or 4.0 dS·m–1. In the summer study, after 10 weeks of treatment, Achillea millefolium L., Gaillardia aristata Foug., and Salvia coccinea Juss ex J. had an aesthetically acceptable appearance for landscape performance (visual quality scores of 4 points or more), whereas Agastache cana (Hook.) Woot. & Standl. and Echinacea purpurea (L.) Moench had relatively low tolerance to salinity. Dry weight of shoots of A. millefolium, A. cana, and G. arstata was lower at elevated salinity levels. In the fall study, A. millefolium, E. purpurea, G. arstata, and S. coccinea had acceptable growth and visual quality at elevated salinity levels, whereas A. cana had lower quality and reduced growth. Dry weight of shoots was lower in G. arstata and A. millefolium at an EC of 2.0 dS·m–1 or 4.0 dS·m–1. Leaf osmotic potential of all species in the summer experiment was significantly lower at higher salinity compared with the control. In the fall experiment, leaf osmotic potential in A. millefolium, E. purpurea, and G. aristata at 4 dS·m–1 was lower compared with lower salinity treatment and the control. Leaf osmotic potential in the fall was higher than that of the same species at the same salinity level in the summer experiment, indicating that plants in the fall were less stressed than in the summer. Combined the results from both experiments, the authors concluded that A. millefolium, G. arstata, and S. coccinea had a relatively high salt tolerance (as much as 4 dS·m–1 of irrigation water under greenhouse conditions) among the tested species, whereas A. cana and E. purpurea were not tolerant to salt and should not be irrigated with low-quality water.

scholarly journals Differences in water relations and total carbohydrate content between precommercially thinned and unthinned Pinus nigra subsp. pallasiana stands

2021 ◽  
Vol 67 (No. 3) ◽  
pp. 125-133
Author(s):  
Ayşe Deligöz ◽  
Esra Bayar ◽  
Musa Genç ◽  
Yasin Karatepe
Keyword(s):  
Water Relations ◽  
Osmotic Potential ◽  
Weight Fraction ◽  
Dry Weight ◽  
Water Shortage ◽  
Pinus Nigra ◽  
Carbohydrate Content ◽  
Total Carbohydrate ◽  
Total Carbohydrate Content ◽  
Relative Water

Variations in seasonal responses in water relations and total carbohydrate content (TCC) in one-yearold shoots from precommercially thinned (PCT) and unthinned Anatolian black pine stands were assessed during three seasons (sampling in May, July and September) in 2015–2017. Three different treatments were established: unthinned control with 4 941 stems·ha–1 and two thinned spacing levels (2–2.5 and 3–3.5 m) where 2 133 stems·ha<sup>–1</sup> and 1 093 stems·ha<sup>–1</sup> were left, respectively. Differences in osmotic potential at turgor loss point (Ψπ<sub>TLP</sub>) between the thinned and unthinned plots appeared only during a water shortage (September) in the second season, with the thinned stands showing lower Ψπ<sub>TLP</sub> than the unthinned stands. Seasonal variation in terms of Ψπ<sub>TLP</sub> was detected in the 3–3.5 m spacing trees. PCT were effective on osmotic potential at full turgor (Ψπ<sub>100</sub>), relative water content (RWC), symplastic water at saturated point per dry weight of the shoot and dry weight fraction. In both the thinned and unthinned plots, a gradual decline was observed in RWC from May to September in all three years. Generally, although TCC was found to be higher in the 3–3.5 m spacing, control plots were also high in carbohydrates in some periods. Results reflect the ability of this species to survive in changing environments by PCT during dry periods in the three studied seasons. Although PCT has an effect on water potential components and TCC, it is not clear exactly how effective the PCT density is in osmotic adjustment.

Growth and Osmotic Relations of the Mangrove Avicennia marina, as Influenced by Salinity

1982 ◽  
Vol 9 (5) ◽  
pp. 519 ◽  
Author(s):  
WJS Downton
Keyword(s):  
Nutrient Solution ◽  
Osmotic Potential ◽  
Dry Weight ◽  
Avicennia Marina ◽  
Natural Seawater ◽  
Charge Balance ◽  
Leaf Extracts ◽  
Salt Glands ◽  
Wide Range ◽  
Osmotic Potentials

Seeds of the mangrove Avicennia marina were germinated and grown for up to 11 months on nutrient solution or nutrient solution containing 10, 25, 50, 75 or 100% natural seawater (500 mM sodium; 580 mM chloride). Early seedling development was most rapid in the absence of sodium chloride, but soon declined. As a result, biomass production in this treatment was poorest. The response was associated with the appearance of necrotic lesions. The growth optimum based on fresh or dry weight occurred on 10, 25 or 50% seawater. Plants receiving higher salinities, particularly full strength seawater, were slow to develop, and low in biomass, but healthy in appearance. Seeds taken from parent trees growing on tidal mudflats had osmotic potentials more negative than seawater, but contained little sodium or chloride, potassium being the most abundant inorganic ion. The osmotic potentials of the seedlings were more negative than those of the external watering solutions by at least 2 MPa in all of the treatments. Turgor pressures of approximately 0.8 MPa were evident for the salt-treated plants, but were much lower (0.2-0.3 MPa) for plants receiving only nutrient. Seedlings grown on nutrient alone accumulated mainly potassium (sodium and chloride being unavailable) and probably depended upon organic substances, in particular organic anions, to generate internal osmotic potential. Plants on 10-100% seawater treatments behaved as typical halophytes accumulating increasing levels of sodium and chloride as external salinity increased, even though the leaves can regulate steady-state ionic concentrations by means of salt glands. Sodium replaced potassium, but preferential potassium uptake was maintained over a wide range of external sodium concentrations. Chloride accumulation balanced approximately half of the cations present. The calculated osmotic contribution made by the cations (assuming complete charge balance by chloride) in the leaf extracts corresponded closely to measured osmotic potential.

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