scholarly journals ABA AND STOMATAL RESPONSES IN TEPARY AND COMMON BEAN

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 682b-682
Author(s):  
Maria G. Janssen ◽  
Albert H. Markhart
Keyword(s):  
Common Bean ◽  
Xylem Sap ◽  
Drought Tolerant ◽  
Detached Leaves ◽  
Stomatal Sensitivity ◽  
Root Signal ◽  
Response To Water ◽  
Aba Content ◽  
The Relationship

Tepary beans (Phaseolus acutifolius Gray) are more drought tolerant and have stomata that are more sensitive to low leaf water potentials (ψ w) than common beans (P. vulgaris L.). This study was designed to examine the role of ABA in controlling stomatal behaviour in these species. Comparison of the bulk leaf ABA content does not explain why tepary stomata are more sensitive to low leaf ψ w compared to common bean (at -1.4 MPa ABA content increased 40-fold in common bean and 25-fold in tepary). We hypothesize that the greater sensitivity of tepary stomata to low leaf ψ w is related to a higher concentration of ABA in the xylem sap, and/or to a greater sensitivity of tepary stomata to ABA. Xylem sap of well-watered and water stressed plants is analyzed to determine the concentration of ABA, and whether ABA is a putative candidate serving as a chemical root signal in response to water stress in Phaseolus. To test stomatal sensitivity to ABA, epidermal strips and detached leaves are exposed to a range of ABA concentrations. The relationship between stomatal aperture and different ABA concentrations is discussed.

scholarly journals Gibberellin in tomato: metabolism, signaling and role in drought responses

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Hagai Shohat ◽  
Natanella Illouz Eliaz ◽  
David Weiss
Keyword(s):  
Tomato Plant ◽  
Plant Response ◽  
Water Deficiency ◽  
Drought Avoidance ◽  
Drought Tolerant ◽  
Improved Performance ◽  
Plant Life Cycle ◽  
Response To Water ◽  
Signaling Components

AbstractThe growth-promoting hormone gibberellin (GA) regulates numerous developmental processes throughout the plant life cycle. It also affects plant response to biotic and abiotic stresses. GA metabolism and signaling in tomato (Solanum lycopersicum) have been studied in the last three decades and major components of the pathways were characterized. These include major biosynthesis and catabolism enzymes and signaling components, such as the three GA receptors GIBBERELLIN INSENSITIVE DWARF 1 (GID1) and DELLA protein PROCERA (PRO), the central response suppressor. The role of these components in tomato plant development and response to the environment have been investigated. Cultivated tomato, similar to many other crop plants, are susceptible to water deficiency. Numerous studies on tomato response to drought have been conducted, including the possible role of GA in tomato drought resistance. Most studies showed that reduced levels or activity of GA improves drought tolerance and drought avoidance. This review aims to provide an overview on GA biosynthesis and signaling in tomato, how drought affects these pathways and how changes in GA activity affect tomato plant response to water deficiency. It also presents the potential of using the GA pathway to generate drought-tolerant tomato plants with improved performance under both irrigation and water-limited conditions.

Abscisic acid content and components of water status in leaves of Populus deltoides

1986 ◽  
Vol 64 (10) ◽  
pp. 2295-2298 ◽  
Author(s):  
Tsai-Yun Lin ◽  
Edward Sucoff ◽  
Mark Brenner
Keyword(s):  
Abscisic Acid ◽  
Populus Deltoides ◽  
Water Status ◽  
Leaf Water ◽  
Leaf Water Status ◽  
Eastern Cottonwood ◽  
Detached Leaves ◽  
Aba Content ◽  
The Relationship ◽  
Abscisic Acid Content

The relationship between abscisic acid (ABA) and leaf water status was studied during the air drying of detached leaves of eastern cottonwood (Populus deltoides Marsh.). The ABA content increased exponentially as leaf water potential and leaf turgor potential decreased. No clearly defined thresholds were observed between ABA content and these variables. ABA content was linearly related to the relative fresh weight and was not related to the osmotic potential.

Effects of growth temperature on the response of lupin stomata to drought and abscisic acid

1999 ◽  
Vol 26 (6) ◽  
pp. 549 ◽  
Author(s):  
M. Leonor Osório ◽  
M. Lucília Rodrigues ◽  
M. Manuela Chaves ◽  
Maria João Correia
Keyword(s):  
Abscisic Acid ◽  
Growth Temperature ◽  
Water Status ◽  
Lupinus Albus ◽  
Xylem Sap ◽  
Effect Of Temperature ◽  
Exogenous Aba ◽  
Higher Temperature ◽  
Stomatal Sensitivity ◽  
The Relationship

To assess how growth temperature affects stomatal responses to xylem-transported abscisic acid (ABA), leaf conductance (g), the concentrations of ABA and calcium ions, and the pH of the xylem sap were measured in well-watered and water-stressed Lupinus albus L. plants grown under two thermal regimes: 10/15°C and 20/25°C, night/day temperature. Moderate water deficit was imposed, at the same thermal time, and induced a significant reduction in g regardless of temperature. In the morning, g was higher in plants grown at 20/25°C than in cooler conditions, and these differences could not be explained by dissimilarities in shoot water status or xylem ABA concentration. At midday, the apparent stomatal sensitivity to xylem-carried ABA was increased and the effect of temperature on the relationship between g and xylem ABA was no longer observed. A positive effect of higher temperature on stomatal aperture was also evident when artificial sap containing ABA was fed to leaves of well-watered plants. In response to exogenous ABA, stomata closed to the same extent as observed in the morning in water-stressed plants. However, exogenous ABA feeding could not mimic the relationship between g and xylem ABA determined at midday in intact plants. The pH and the concentration of calcium in xylem were not affected by temperature. At midday, however, the calcium concentrations were higher in water-stressed than in well-watered plants. These changes in the concentrations of calcium or other xylem components, such as ABA conjugates, together with possible changes in the ability of the leaves to degrade and/or to compartmentalise ABA, may partly explain the midday increase in the apparent stomatal sensitivity to xylem ABA.

scholarly journals   Role of abscisic acid and drought stress on the activities of antioxidant enzymes in wheat

2012 ◽  
Vol 58 (No. 4) ◽  
pp. 181-185 ◽  
Author(s):  
A. Bano ◽  
F. Ullah ◽  
A. Nosheen
Keyword(s):  
Abscisic Acid ◽  
Drought Stress ◽  
Seed Treatment ◽  
Oxygen Species ◽  
Wheat Cultivars ◽  
Drought Tolerant ◽  
Relative Water ◽  
Aba Content ◽  
Endogenous Aba

The effect of drought stress and abscisic acid (ABA) applied at tillering stage (55 days after sowing) was compared in 2 wheat cultivars differing in drought tolerance. The activities of superoxide dismutase (SOD) and peroxidase (POD) and contents of endogenous ABA in plants were measured at 3 days of drought stress in cv. Chakwal-97 (drought tolerant) and cv. Punjab-96 (drought susceptible). ABA was applied at 10<sup>&ndash;6</sup> mol/L as presowing seed treatment for 18 h. Drought tolerant cultivar has a more efficient mechanism to scavenge reactive oxygen species as shown by a significant increase in the activity of antioxidant enzyme SOD. Under drought stress, ABA significantly increased the activities of SOD and POD, showing a significant decline on rewatering. The relative water content was significantly increased by ABA priming under drought stress in both wheat cultivars. The sensitive cultivar exhibiting lower endogenous ABA content was more responsive to ABA priming. On rewatering, the magnitude of recovery from drought stress was greater in tolerant cultivar. ABA was highly effective in improving grain weight of tolerant cultivar under drought stress. &nbsp;

scholarly journals ACCUMULATION, DISTRIBUTION AND FUNCTIONAL ROLE OF ABSCISIC ACID UNDER SHORT-TERM SALT STRESS IN WHEAT PLANTS

ÈKOBIOTEH ◽  
2021 ◽  
Vol 4 (4) ◽  
pp. 269-275
Author(s):  
R.S. Ivanov ◽  
◽  
L.B. Vysotskaya ◽  
G.V. Sharipova ◽  
D.S. Veselov ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Salt Stress ◽  
Acid Metabolism ◽  
Xylem Sap ◽  
Plant Leaves ◽  
Short Term ◽  
Rapid Accumulation ◽  
Abscisic Acid Metabolism ◽  
Root Signal

Local effects on plant roots or shoots are accompanied by a change of plant hormones concentration providing signal transduction in plants and their adaptation to changing environmental conditions. It is known that plants respond to drought stress by increasing the concentration of abscisic acid (ABA) in xylem sap which leads to decrease in stomatal conductance to prevent plant water loss from transpirational pathways. Earlier, we found a rapid leaf ABA accumulation in barley and wheat plants under influence of the shortterm salinity. However, the mechanism of the salt stress induced rapid accumulation of abscisic acid in plant leaves remained unclear. The aim of this study was to investigate whether the salt-induced rapid accumulation of abscisic acid in the leaves was the result of its inflow from the roots (as a root signal). In our experiments the short-term salinity did not increase but decreased the concentration of abscisic acid in xylem sap of wheat plants. Thus, detected accumulation of ABA in the leaves did not result from an increase in its inflow from the roots. Apparently leaf ABA accumulation already detected in 15 min after the onset of salinity stress could be a local reaction due to its metabolism in the shoot itself. The decrease in the leaf water potential could induce the change of abscisic acid metabolism pathways in the shoot that led to the accumulation of this hormone. A small short-term accumulation of ABA in the roots did not lead to an increase in their hydraulic conductivity.

scholarly journals Differential accumulation of mRNAs in drought-tolerant and susceptible common bean cultivars in response to water deficit

2007 ◽  
Vol 0 (0) ◽  
pp. 071026235358001-??? ◽  
Author(s):  
Lourdes Montalvo-Hernández ◽  
Elías Piedra-Ibarra ◽  
Lidia Gómez-Silva ◽  
Rosalía Lira-Carmona ◽  
Jorge A. Acosta-Gallegos ◽  
...  
Keyword(s):  
Common Bean ◽  
Water Deficit ◽  
Drought Tolerant ◽  
Response To Water

scholarly journals Dynamic changes in ABA content in water-stressed Populus nigra: effects on carbon fixation and soluble carbohydrates

2019 ◽  
Vol 124 (4) ◽  
pp. 627-643 ◽  
Author(s):  
Cecilia Brunetti ◽  
Antonella Gori ◽  
Giovanni Marino ◽  
Paolo Latini ◽  
Anatoly P Sobolev ◽  
...  
Keyword(s):  
Gene Expression ◽  
Water Stress ◽  
Water Deficit ◽  
Leaf Gas Exchange ◽  
Xylem Sap ◽  
Populus Nigra ◽  
Soluble Carbohydrates ◽  
Intrinsic Water Use Efficiency ◽  
Response To Water ◽  
Aba Content

AbstractBackground and AimsHydraulic and chemical signals operate in tandem to regulate systemic plant responses to drought. Transport of abscisic acid (ABA) through the xylem and phloem from the root to shoot has been suggested to serve as the main signal of water deficit. There is evidence that ABA and its ABA-glycosyl-ester (ABA-GE) are also formed in leaves and stems through the chloroplastic 2-C-methylerythritol-5-phosphate (MEP) pathway. This study aimed to evaluate how hormonal and hydraulic signals contribute to optimize stomatal (gs), mesophyll (gm) and leaf hydraulic (Kleaf) conductance under well-watered and water-stressed conditions in Populus nigra (black poplar) plants. In addition, we assessed possible relationships between ABA and soluble carbohydrates within the leaf and stem.MethodsPlants were subjected to three water treatments: well-watered (WW), moderate stress (WS1) and severe stress (WS2). This experimental set-up enabled a time-course analysis of the response to water deficit at the physiological [leaf gas exchange, plant water relations, (Kleaf)], biochemical (ABA and its metabolite/catabolite quantification in xylem sap, leaves, wood, bark and roots) and molecular (gene expression of ABA biosynthesis) levels.Key ResultsOur results showed strong coordination between gs, gm and Kleaf under water stress, which reduced transpiration and increased intrinsic water use efficiency (WUEint). Analysis of gene expression of 9-cis-epoxycarotenoid dioxygenase (NCED) and ABA content in different tissues showed a general up-regulation of the biosynthesis of this hormone and its finely-tuned catabolism in response to water stress. Significant linear relationships were found between soluble carbohydrates and ABA contents in both leaves and stems, suggesting a putative function for this hormone in carbohydrate mobilization under severe water stress.ConclusionsThis study demonstrates the tight regulation of the photosynthetic machinery by levels of ABA in different plants organs on a daily basis in both well-watered and water stress conditions to optimize WUEint and coordinate whole plant acclimation responses to drought.

Stomatal Conductance and ABA Concentration in the Xylem Sap of Barley Lines of Contrasting Genetic Origins

1997 ◽  
Vol 24 (5) ◽  
pp. 607 ◽  
Author(s):  
Ch. Borel ◽  
Th. Simonneau ◽  
D. This ◽  
F. Tardieu
Keyword(s):  
Stomatal Conductance ◽  
Water Status ◽  
Xylem Sap ◽  
Cycle Duration ◽  
Response Curves ◽  
Hordeum Vulgare L ◽  
Drought Tolerant ◽  
Series Of Experiments ◽  
Stomatal Sensitivity ◽  
Unique Relationship

We investigated the controls of ABA concentration in the xylem sap and of stomatal conductance in five barley (Hordeum vulgare L.) lines of contrasting origins (Syrian or French), genetic backgrounds and previously field-evaluated drought resistances. Controlled water deficits were applied to young plants in a series of experiments in the greenhouse with contrasting evaporative demands. There was a unique relationship between soil water status and the concentration of ABA in the xylem sap measured at the end of the night. This relationship applied to all experiments for a given line, and was common between lines. Concentrations measured in the sap collected by pressurising leaves were similar to those in the sap of pressurised roots. Stomatal conductance was related to the concentration of ABA in the sap, with relationships which were common for all experiments within each line. Response curves of gs to concentration of ABA in the sap differed among two groups of lines which slightly differed in life cycle duration. Apparent stomatal sensitivity to ABAwas lower in earliest anthesing lines. Both groups comprised lines of either Syrian or French origins, and either ‘drought tolerant’ or ‘drought susceptible’ lines. We conclude that stomatal control had a low genetic variability in the studied range of lines, in spite of the large genetic differences between lines.

Choosing a Markov blanket

2020 ◽  
Vol 43 ◽  
Author(s):  
Thomas Parr
Keyword(s):  
Markov Blanket ◽  
Target Article ◽  
The Relationship

Abstract This commentary focuses upon the relationship between two themes in the target article: the ways in which a Markov blanket may be defined and the role of precision and salience in mediating the interactions between what is internal and external to a system. These each rest upon the different perspectives we might take while “choosing” a Markov blanket.

Staring Down Death

Crisis ◽  
2016 ◽  
Vol 37 (3) ◽  
pp. 212-217 ◽  
Author(s):  
Thomas E. Joiner ◽  
Melanie A. Hom ◽  
Megan L. Rogers ◽  
Carol Chu ◽  
Ian H. Stanley ◽  
...  
Keyword(s):  
Suicide Risk ◽  
Clinical Utility ◽  
Blink Rate ◽  
Specific Task ◽  
Careful Planning ◽  
Eye Blink ◽  
Eye Blinks ◽  
Potential Clinical Utility ◽  
The Relationship

Abstract. Background: Lowered eye blink rate may be a clinically useful indicator of acute, imminent, and severe suicide risk. Diminished eye blink rates are often seen among individuals engaged in heightened concentration on a specific task that requires careful planning and attention. Indeed, overcoming one’s biological instinct for survival through suicide necessitates premeditation and concentration; thus, a diminished eye blink rate may signal imminent suicidality. Aims: This article aims to spur research and clinical inquiry into the role of eye blinks as an indicator of acute suicide risk. Method: Literature relevant to the potential connection between eye blink rate and suicidality was reviewed and synthesized. Results: Anecdotal, cognitive, neurological, and conceptual support for the relationship between decreased blink rate and suicide risk is outlined. Conclusion: Given that eye blinks are a highly observable behavior, the potential clinical utility of using eye blink rate as a marker of suicide risk is immense. Research is warranted to explore the association between eye blink rate and acute suicide risk.

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