The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform
Edward L. Deckard - One of the best experts on this subject based on the ideXlab platform.
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The effect of Osmotic Potential on anther culture in spring wheat ( Triticum aestivum )
Plant Cell Tissue and Organ Culture, 2003Co-Authors: Tae-jin Kang, Moon-sik Yang, Edward L. DeckardAbstract:This study was conducted to determine the effect of Osmotic Potential in a modified 85D12 medium on both callus induction and plant regeneration in the anther culture of two wheat genotypes, cv. Chris and cv. Pavon. Altering the medium Osmotic Potential by changing the carbohydrate source and concentration or by adding a non-metabolized Osmoticum appeared to have the greatest Potential for improving anther-derived green plant production. The medium Osmotic Potentials were varied (-0.67 to −2.30 MPa) by altering sucrose and PEG concentration. Both Osmotica affected callus production, with −0.9 to −1.4 MPa media producing the most calluses. Callus production depended on genotype and Osmoticum. Only PEG concentration affected green plant regeneration. The greatest number of green plants (11.5 plants per 100 anthers in cv. Chris) was obtained with 0.0125 M of PEG. This experiment suggested that a low level of PEG in the medium was beneficial for producing green plants from wheat anthers.
Yvan Pelletier - One of the best experts on this subject based on the ideXlab platform.
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A phloem-sap feeder mixes phloem and xylem sap to regulate Osmotic Potential
Journal of Insect Physiology, 2011Co-Authors: Julien Pompon, Dan T. Quiring, Claudia Goyer, Philippe Giordanengo, Yvan PelletierAbstract:Abstract Phloem-sap feeders (Hemiptera) occasionally consume the dilute sap of xylem, a behaviour that has previously been associated with replenishing water balance following dehydration. However, a recent study reported that non-dehydrated aphids ingested xylem sap. Here, we tested the hypothesis that the consumption of xylem sap, which has a low osmolality, is a general response to Osmotic stresses other than dehydration. Alate aphids were subjected to different treatments and subsequently transferred onto a plant, where electrical penetration graph (EPG) was used to estimate durations of passive phloem sap consumption and active sucking of xylem sap. The proportion of time aphids fed on xylem sap (i.e., time spent feeding on xylem sap/total time spent feeding on phloem plus xylem sap) was used as a proxy of the solute concentration of the uptake. The proportion of time alate aphids fed on xylem sap increased: (1) with the time spent imbibing an artificial diet containing a solution of sucrose, which is highly concentrated in phloem sap and is mainly responsible for the high Osmotic Potential of phloem sap; (2) with the Osmotic Potential of the artificial diet, when Osmotic Potential excess was not related to sucrose concentration; and (3) when aphids were deprived of primary symbionts, a condition previously shown to lead to a higher haemolymph Osmotic Potential. All our results converge to support the hypothesis that xylem sap consumption contributes to the regulation of the Osmotic Potential in phloem-sap feeders.
Tae-jin Kang - One of the best experts on this subject based on the ideXlab platform.
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The effect of Osmotic Potential on anther culture in spring wheat ( Triticum aestivum )
Plant Cell Tissue and Organ Culture, 2003Co-Authors: Tae-jin Kang, Moon-sik Yang, Edward L. DeckardAbstract:This study was conducted to determine the effect of Osmotic Potential in a modified 85D12 medium on both callus induction and plant regeneration in the anther culture of two wheat genotypes, cv. Chris and cv. Pavon. Altering the medium Osmotic Potential by changing the carbohydrate source and concentration or by adding a non-metabolized Osmoticum appeared to have the greatest Potential for improving anther-derived green plant production. The medium Osmotic Potentials were varied (-0.67 to −2.30 MPa) by altering sucrose and PEG concentration. Both Osmotica affected callus production, with −0.9 to −1.4 MPa media producing the most calluses. Callus production depended on genotype and Osmoticum. Only PEG concentration affected green plant regeneration. The greatest number of green plants (11.5 plants per 100 anthers in cv. Chris) was obtained with 0.0125 M of PEG. This experiment suggested that a low level of PEG in the medium was beneficial for producing green plants from wheat anthers.
Moritz Knoche - One of the best experts on this subject based on the ideXlab platform.
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Predicting Osmotic Potential from measurements of refractive index in cherries, grapes and plums
PloS one, 2018Co-Authors: Andreas Winkler, Moritz KnocheAbstract:Studies of fruit tree water relations often require data on water Potentials of fruit. However, this is sometimes difficult because the fruit stalks are not sufficiently long for use in a pressure bomb. Also, because fruit xylem function is often lost during maturation. In the absence of significant turgor, the Osmotic Potential of the expressed juice is a useful proxy for a fruit’s water Potential. The Osmotic Potential of most fleshy fruit is determined largely by the concentration of soluble carbohydrates and this can be quantified by osmometry. Soluble solids may also be quantified by refractometry. Compared with osmometry, refractometry is markedly less expensive and also much faster. Hence, it is better suited to high-throughput analyses. The objective of this study was to establish relationships between the Osmotic Potentials of juices expressed from sweet cherries and sour cherries, grapes and plums as determined using a vapor pressure osmometer and their soluble solids concentrations as determined using a refractometer. The data reveal close relationships within all these species. Except for plums, the relationships between species were almost identical. This is due to similarity among cultivars and species in the relative abundances of the same set of major osmolytes—i.e. the carbohydrates glucose, fructose and sorbitol and the potassium salts of the organic acids malate or tartrate. For plums, the relationship between Osmotic Potential and soluble solids concentration was slightly displaced. Our findings indicate Osmotic Potentials may be reliably predicted from soluble solids concentrations determined by refractometry.
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Sweet Cherry Skin Has a Less Negative Osmotic Potential than the Flesh
Journal of the American Society for Horticultural Science, 2015Co-Authors: Eckhard Grimm, Moritz KnocheAbstract:The skin is the primary load-bearing structure in a sweet cherry fruit (Prunus avium L.). Failure of the skin in rain cracking is considered to be related to water uptake. Little is known of the skin’s water Potential, its Osmotic Potential (ΨΠS), and turgor. The objective here was to quantify ΨΠS relative to the Osmotic Potential of the flesh (ΨΠF). Spatial resolution was achieved by monitoring plasmolysis in epidermal cells in tissue sections, incubated in selected Osmotica using a light microscope method. Decreasing the Osmotic Potential [ΨΠ (more negative)] of the incubation medium increased the proportion (percent) of plasmolyzed epidermal cells. The pattern of increasing plasmolysis was sigmoidal with increasing osmolyte concentration. The value of ΨΠ for 50% of cells plasmolyzed, depended to some extent on the osmolyte used. The value of ΨΠ became slightly less negative for the osmolytes tested in the order: 1) mannitol, 2) sucrose, and 3) artificial cherry juice (a solution comprising the five major osmolytes of sweet cherry juice in the appropriate proportions and concentrations). There was little difference in the value of ΨΠ at 50% plasmolysis between the cultivars Hedelfinger, Sam, and Sweetheart. In all three cultivars, the value of ΨΠF (measured for expressed juice using an osmometer) was markedly more negative than that of ΨΠS (measured for 50% plasmolysis). Incubating skin segments in juice from the same fruit resulted in the plasmolysis of most (85.7% to 96.4%) of the epidermal cells. As fruit development progressed from stage II [27 day after full bloom (DAFB)] to the fully mature stage III (97 DAFB), plasmolysis occurred for increasingly more negative values of ΨΠ. Moreover, the difference between the Osmotic Potential values recorded for the flesh ΨΠF and for the skin ΨΠS increased. Plasmolysis of epidermal cells was accompanied by a marked swelling of their walls. The results indicate a marked difference in the Osmotic Potential of flesh (ΨΠF trended more negative) and skin cells (ΨΠS trended less negative).
Mark A Adams - One of the best experts on this subject based on the ideXlab platform.
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leaf Osmotic Potential of eucalyptus hybrids responds differently to freezing and drought with little clonal variation
Tree Physiology, 2008Co-Authors: Andrew Callister, Stefan K Arndt, Andrew Merchant, Peter K Ades, Douglas M Rowell, Mark A AdamsAbstract:Concentrations of solutes, and thus leaf Osmotic Potential (Psi pi), often increase when plants are subject to drought or sub-zero (frost) temperatures. We measured Psi pi and concentrations of individual solutes in leaves of 3-year-old Eucalyptus camaldulensis Dehn., E. globulus Labill., E. grandis W. Hill ex Maid. and 29 hybrid clones on a site subjected to both summer drought and winter frost. We sought to characterize seasonal and genetic variations in Psi pi and to determine whether Psi pi or leaf turgor is related to bole volume increment. Leaf Osmotic Potential at full turgor (Psi pi(100)) was 0.7 MPa more negative in winter than in late summer, and this trend was uniform across genotypes. Soluble carbohydrates were confirmed as key contributors to Psi pi, accounting for 40-44% of total osmolality. The seasonal trend in Psi pi(100) was facilitated by changes in leaf morphology, such as reduced turgid mass:dry mass ratio and increased apoplastic water fraction in winter. Cell wall elasticity increased significantly from winter to summer. Our results suggest that elastic adjustment may be more important than Osmotic adjustment in leaves exposed to drought. Although Psi pi(100) was a reasonable predictor of in situ Osmotic Potential and turgor, we found no relationship between any physiological trait and bole volume increment. Clone-within-family variation in Psi pi(100) was small in both summer and winter and was unrelated to bole volume increment. We conclude that, for the study species, tree improvement under water-limited conditions should concentrate on direct selection for growth rather than on indirect selection based on Osmotic Potential.
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Comparison of four methods for measuring Osmotic Potential of tree leaves
Physiologia Plantarum, 2006Co-Authors: Andrew N. Callister, Stefan K Arndt, Mark A AdamsAbstract:Osmotic Potential (pi) of tree leaves is usually determined by pressure-volume (PV) analysis, which is too time consuming for large-scale assessments such as ecological surveys and genetic screening. We investigated methods for rapid measurement of pi in sclerophyllous species. The Osmotic Potential of expressed sap (ES), freeze-thaw leaf discs and hot water extracts - measured using a variety of techniques - were compared with PV analysis using sclerophyllous species; Eucalyptus globulus Labill., E camaldulensis Dehnh., E. cladocalyx F. Muell. and non-sclerophyllous species; Populus nigra L and Alnus jorullensis H.B.K. All methods were sensitive to changes in pi and produced results that were unequal but well correlated (r(2) 0.82-0.90). The proportion of leaf water extracted in ES was reduced by low water content and sclerophylly without affecting method accuracy. PV analysis provided a poor correction for apoplastic dilution of ES. Results of ES osmometry and PV analysis were comparable, and osmometry of ES is proposed as a suitable method for large-scale investigations of leaf pi.
