Photosynthesis and the Accumulation of Proline in Response to Water Deficit

1992 ◽  
Vol 19 (3) ◽  
pp. 249 ◽  
Author(s):  
PA Joyce ◽  
D Aspinall ◽  
LG Paley
Keyword(s):  
Water Stress ◽  
Potential Energy ◽  
Energy Supply ◽  
Proline Accumulation ◽  
Soluble Carbohydrate ◽  
Light Stimulation ◽  
Stress Energy ◽  
Response To Water ◽  
Stimulation Of

Light increases proline accumulation in water-stressed excised leaves of barley, and the response is linked to photosynthesis. The manner in which current photosynthesis contributes to proline accumulation and the role of soluble tissue carbohydrates has been examined. Increasing the CO2 content of the air surrounding stressed tissue had no effect on proline accumulation and reducing it to zero reduced proline accumulation only in leaves previously kept in darkness. The direct contribution of assimilated carbon to proline synthesis, assessed with labelled CO2, was small (< 10% of accumulated proline). The potential energy supply from photosynthesis during water stress was more than adequate for proline synthesis, but the potential energy supply from carbohydrate oxidation for segments stressed in darkness became limiting in leaves incubated in darkness for 48 h before stress. Energy provision from current photosynthesis may thus contribute to light stimulation of proline accumulation. Illumination modified the soluble carbohydrate content of the leaf segments and these variations were related to the rates of proline synthesis and oxidation. However, these effects were over-ridden by stress, and the mechanism of the response to light is not fully explained.

Osmotic Adjustment: Effect of Water Stress on Carbohydrates in Leaves, Stems and Roots of Apple

1995 ◽  
Vol 22 (5) ◽  
pp. 747 ◽  
Author(s):  
Z Wang ◽  
B Quebedeaux ◽  
GW Stutte
Keyword(s):  
Water Stress ◽  
Osmotic Adjustment ◽  
Sucrose Concentration ◽  
Starch Content ◽  
Soluble Carbohydrates ◽  
Soluble Carbohydrate ◽  
Malus Domestica Borkh ◽  
Mature Leaves ◽  
Young Leaves ◽  
Response To Water

Potted apple (Malus domestica Borkh. cv. Jonathan) trees were subjected to water stress in a greenhouse. Midday leaf water potential (ΨW), osmotic potential (ΨS), soluble carbohydrates, and starch content of expanding and mature leaves, stems, and roots were measured to determine whether active osmotic adjustment occurred and if water stress affected carbohydrate metabolism. Mature leaves had the highest total soluble carbohydrate level (357 mM) and lowest Ψ (-1.85 MPa), followed by young leaves (278 mM, -1.58 MPa), stems (115 mM, -1.02 MPa), and roots (114 mM, -0.87 MPa). Sorbitol was the major component in all organs ranging from 53% of total soluble carbohydrate in young leaves to 73% in mature leaves. When ΨW decreased from -1.0 to -3.2 MPa, active osmotic adjustments of 0.3-0.4 MPa were observed in mature leaves, stems, and roots while a significantly higher adjustment of 1.0 MPa was detected in young leaves 5 days after the initiation of water stress. Sorbitol levels in leaves and stems gradually increased as ΨW decreased from -1.0 to -2.5 MPa, and then remained relatively stable or decreased slightly as ΨW decreased from -2.5 to -3.2 MPa. However, the percentage of soluble carbohydrate as sorbitol in roots decreased in response to water stress. Sucrose concentration decreased in mature leaves and stems, but increased in young leaves and roots as ΨW decreased. Starch concentrations in stems and roots also decreased as water stress developed. The sorbitol to sucrose ratios increased in mature leaves, but decreased in roots in response to water stress.

scholarly journals Role of leaf hydraulic conductance in the regulation of stomatal conductance in almond and olive in response to water stress

2016 ◽  
Vol 36 (6) ◽  
pp. 725-735 ◽  
Author(s):  
Virginia Hernandez-Santana ◽  
Celia M. Rodriguez-Dominguez ◽  
J. Enrique Fernández ◽  
Antonio Diaz-Espejo
Keyword(s):  
Water Stress ◽  
Stomatal Conductance ◽  
Hydraulic Conductance ◽  
Leaf Hydraulic Conductance ◽  
Response To Water

Turgor maintenance, osmotic adjustment and soluble sugar and proline accumulation in 49 pea cultivars in response to water stress

1998 ◽  
Vol 59 (3) ◽  
pp. 225-235 ◽  
Author(s):  
Francisco J Sánchez ◽  
Marı́a Manzanares ◽  
Eusebio F de Andres ◽  
José L Tenorio ◽  
Luis Ayerbe
Keyword(s):  
Water Stress ◽  
Osmotic Adjustment ◽  
Soluble Sugar ◽  
Proline Accumulation ◽  
Turgor Maintenance ◽  
Response To Water

scholarly journals The Role of Free Proline and Soluble Carbohydrates in Water Gypsum Stress on Some Gypsophyte and Gypsovag Plants

2019 ◽  
Vol 37 ◽  
Author(s):  
E. OZDENIZ
Keyword(s):  
Stress Conditions ◽  
The Other ◽  
Soluble Carbohydrates ◽  
Soluble Carbohydrate ◽  
Free Proline ◽  
Protective Properties ◽  
Other Hand ◽  
Response To Water ◽  
Carbohydrate Contents

ABSTRACT: The aim of this study is to identify the roles of free proline and soluble carbohydrates in water gypsum stress. This study is the first such study on gypsophyte and gypsovag plants. For this purpose, free proline and soluble carbohydrate contents in gypsophyteand gypsovag plants have been analyzed. It is known that proline increases under stress conditions and it is a nitrogen-containing compound with protective properties contributing to durability understress. Soluble carbohydrates accumulating under stress conditions, on the other hand, take on the protective task of regulating cell osmotic density. In gypsophytes, free proline is proportionally high (Ch/Pr:1.5 to 9.3) and the amount of soluble carbohydrates is low. In gypsovag individuals growing on gypsum, proline is proportionally low (Ch/Pr:25.5 to 9.2), but soluble carbohydrates are high. It is found that in gypsovag individuals growing on mediums other than gypsum, the amount of proline increases (Ch/Pr:11.6 to 8.5), but the proportion of soluble carbohydrate decreases. Accordingly, while gypsophytes adapt themselves to high proline amounts in response to water gypsum stress and gypsovags develop resistance to water gypsum stress with high amounts of soluble carbohydrates, it is observed that the Ch/Pr ratio in non-gypsum soils decreases.

scholarly journals Metabolome Profiling Supports the Key Role of the Spike in Wheat Yield Performance

Cells ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 1025
Author(s):  
Omar Vergara-Diaz ◽  
Thomas Vatter ◽  
Rubén Vicente ◽  
Toshihiro Obata ◽  
Maria Teresa Nieto-Taladriz ◽  
...  
Keyword(s):  
Water Stress ◽  
Isotope Composition ◽  
Vegetation Indices ◽  
Wheat Yield ◽  
Canopy Temperature ◽  
Grain Filling ◽  
Relevant Information ◽  
Flag Leaves ◽  
Response To Water

Although the relevance of spike bracts in stress acclimation and contribution to wheat yield was recently revealed, the metabolome of this organ and its response to water stress is still unknown. The metabolite profiles of flag leaves, glumes and lemmas were characterized under contrasting field water regimes in five durum wheat cultivars. Water conditions during growth were characterized through spectral vegetation indices, canopy temperature and isotope composition. Spike bracts exhibited better coordination of carbon and nitrogen metabolisms than the flag leaves in terms of photorespiration, nitrogen assimilation and respiration paths. This coordination facilitated an accumulation of organic and amino acids in spike bracts, especially under water stress. The metabolomic response to water stress also involved an accumulation of antioxidant and drought tolerance related sugars, particularly in the spikes. Furthermore, certain cell wall, respiratory and protective metabolites were associated with genotypic outperformance and yield stability. In addition, grain yield was strongly predicted by leaf and spike bracts metabolomes independently. This study supports the role of the spike as a key organ during wheat grain filling, particularly under stress conditions and provides relevant information to explore new ways to improve wheat productivity including potential biomarkers for yield prediction.

Stimulation of Ca(2+)-dependent exocytosis of the sperm acrosome by cAMP acting downstream of phospholipase A2

Reproduction ◽  
2000 ◽  
pp. 57-68 ◽  
Author(s):  
J Garde ◽  
ER Roldan
Keyword(s):  
Arachidonic Acid ◽  
Phospholipase A2 ◽  
Phospholipase C ◽  
Phosphodiesterase Inhibitors ◽  
Dibutyryl Camp ◽  
Camp Phosphodiesterase ◽  
Ram Sperm ◽  
Camp Formation ◽  
Stimulation Of

Spermatozoa undergo exocytosis in response to agonists that induce Ca2+ influx and, in turn, activation of phosphoinositidase C, phospholipase C, phospholipase A2, and cAMP formation. Since the role of cAMP downstream of Ca2+ influx is unknown, this study investigated whether cAMP modulates phospholipase C or phospholipase A2 using a ram sperm model stimulated with A23187 and Ca2+. Exposure to dibutyryl-cAMP, phosphodiesterase inhibitors or forskolin resulted in enhancement of exocytosis. However, the effect was not due to stimulation of phospholipase C or phospholipase A2: in spermatozoa prelabelled with [3H]palmitic acid or [14C]arachidonic acid, these reagents did not enhance [3H]diacylglycerol formation or [14C]arachidonic acid release. Spermatozoa were treated with the phospholipase A2 inhibitor aristolochic acid, and dibutyryl-cAMP to test whether cAMP acts downstream of phospholipase A2. Under these conditions, exocytosis did not occur in response to A23187 and Ca2+. However, inclusion of dibutyryl-cAMP and the phospholipase A2 metabolite lysophosphatidylcholine did result in exocytosis (at an extent similar to that seen when cells were treated with A23187/Ca2+ and without the inhibitor). Inclusion of lysophosphatidylcholine alone, without dibutyryl-cAMP, enhanced exocytosis to a lesser extent, demonstrating that cAMP requires a phospholipase A2 metabolite to stimulate the final stages of exocytosis. These results indicate that cAMP may act downstream of phospholipase A2, exerting a regulatory role in the exocytosis triggered by physiological agonists.

Regulation of Electricity Storage, Intelligent Grids, and Clean Energies in an Open Market in Mexico

2018 ◽  
Author(s):  
José Juan González Márquez ◽  
Margarita González Brambila
Keyword(s):  
Energy Storage ◽  
Energy Supply ◽  
Carbon Dioxide Emission ◽  
Energy Transition ◽  
Legal Framework ◽  
Open Market ◽  
Innovative Strategy ◽  
Electricity Storage ◽  
Storage Technologies

This chapter analyses the role of electricity storage as an innovative strategy to attain the Mexican Government’s goals regarding carbon dioxide emission reduction and energy transition. The survey includes the analysis of the different electricity storage technologies as well as the legal framework governing electricity storage as the fifth link of the energy supply chain from a comparative perspective. The authors discuss whether energy storage is a generation or a distribution/transmission asset. The chapter also analyses Mexico’s experiences in energy storage and briefly describes the way it is regulated in other jurisdictions. Finally, the authors propose the regulation of energy storage as a separate licensed activity.

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