scholarly journals Biochemical responses of Digitaria commutata and Cenchrus ciliaris to water stress: antioxidative reactions, proline and soluble sugars accumulation

2021 ◽  
Vol 33 (3) ◽  
pp. 171-180
Author(s):  
Taoufik Amari ◽  
Chedly Abdelly
Keyword(s):  
Water Stress ◽  
Soluble Sugars ◽  
Antioxidant Enzyme Activities ◽  
Stress Exposure ◽  
Cenchrus Ciliaris ◽  
Psii Photochemistry ◽  
Mda Content ◽  
The Impact ◽  
Quantum Yield Of Psii ◽  
Oxidative System

The impact of water stress on antioxidant enzyme activities, proline, soluble sugars, and carotenoids contents found in Digitaria commutata and Cenchrus ciliaris plants was investigated. Two different watering regimes were used on plants over a period of three months. Water stress decreased total chlorophyll content in plants, but increased carotenoids content. Interestingly, no change was observed in the quantum yield of PSII photochemistry (Fv/Fm). Malondialdehyde (MDA) content increased to a higher extent in both species. Enhanced activities of all the enzymes (peroxidase, catalase, and superoxide dismutase) studied, except for catalase in the roots were observed. Proline and soluble sugars contents increased significantly following water stress exposure. No clear differences were found between both species. The results link drought tolerance of Digitaria commutata and Cenchrus ciliaris plants with better capabilities of anti-oxidative system. Additionally, it is linked to the accretion of osmoprotectants proline and soluble sugars when exposed to drought.

Response of ungrafted and grafted grapevine cultivans and rootstocks (Vitis sp.) to water stress

OENO One ◽  
2007 ◽  
Vol 41 (2) ◽  
pp. 85 ◽  
Author(s):  
Imene Toumi ◽  
Wissal M'Sehli ◽  
Soumaya Bourgou ◽  
Neila Jallouli ◽  
Asma Bensalem-Fnayou ◽  
...  
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Dry Matter ◽  
Soluble Sugars ◽  
Water Shortage ◽  
Stem Water Potential ◽  
Matter Production ◽  
Stem Water ◽  
The Impact ◽  
Progressive Water Stress

<p style="text-align: justify;"><strong>Aims</strong>: The responses of two Vitis vinifera cultivars (Cardinal and Superior Seedless) and two rootstocks (110R and SO4) to drought, the effect of grafting and the interactions of scion/rootstock were investigated.</p><p style="text-align: justify;"><strong>Methods and results</strong>: The vines were subjected to a progressive water stress in greenhouse controlled conditions. At the end of the water stress treatments, physiological analyses were carried out (stem water potential, dry matter production, soluble sugars, proline as well as ions Na+ and K+). Drought was expressed by the drop of the stem water potential in the stressed vines as compared to their controls. Furthermore, tolerance and sensitivity were linked to the accumulation of soluble sugars and proline as well as the equilibrium of K+ and Na+ in the leaves.</p><p style="text-align: justify;"><strong>Conclusion</strong>: When ungrafted, Cardinal was more tolerant to water stress than Superior Seedless. The grafted vines exhibited more vigour, moreover, the combination of Cardinal with SO4 and Superior Seedless with 110R revealed to be the advantageous associations under water stress.</p><p style="text-align: justify;"><strong>Significance and impact of study</strong>: This work has been carried out to investigate the differential responses of grapevine cultivars to drought stress and the impact of grafting under water shortage conditions.</p>

scholarly journals The Decrease of Leaf Dark Respiration during Water Stress Is Related to Leaf Non-Structural Carbohydrate Pool in Vitis vinifera L.

Plants ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 36
Author(s):  
Sergio Tombesi ◽  
Tommaso Frioni ◽  
Francesca Grisafi ◽  
Paolo Sabbatini ◽  
Stefano Poni ◽  
...  
Keyword(s):  
Water Stress ◽  
Dark Respiration ◽  
Soluble Sugars ◽  
Water Shortage ◽  
Stress Conditions ◽  
Plant Water ◽  
Plant Water Stress ◽  
Leaf Dark Respiration ◽  
Structural Carbohydrate ◽  
The Impact

Dark respiration (Rd) is a fundamental plant process used to gain biomass and maintain plant physiological activity. It accounts for the metabolization of a large share of the carbon fixed by photosynthesis. However, Rd during conditions of severe plant water stress is still poorly understood. The decrease in leaf transpiration increases temperature, one of the most important drivers of leaf Rd. On the other hand, water stress decreases the pool of leaf carbohydrates, which are the most important substrate for respiration. The aim of the present work was to determine the impact of water shortage on leaf Rd in grapevine and understand the driving factors in modulating leaf Rd response under plant water stress conditions. Water stressed vines had lower Rd as the water shortage severity increased. Rd was correlated with leaf temperature in well-watered vines. Instead, in water stressed vines, Rd correlated with leaf soluble sugars. The decrease of leaf Rd in water stressed vines was due to the decrease of leaf non-structural carbohydrate that, under water stress conditions, exerted a limiting effect on Rd.

scholarly journals Distinct Respiration and Physiological Changes during Flower Development and Senescence in Two Freesia Cultivars

HortScience ◽  
2010 ◽  
Vol 45 (7) ◽  
pp. 1088-1092 ◽  
Author(s):  
Zhen Shu ◽  
Yimin Shi ◽  
Hongmei Qian ◽  
Yiwei Tao ◽  
Dongqin Tang
Keyword(s):  
Respiration Rate ◽  
Flower Development ◽  
Developmental Stages ◽  
Soluble Sugars ◽  
Membrane Lipid ◽  
Flower Senescence ◽  
Vase Life ◽  
Antioxidant Enzyme Activities ◽  
Freesia Hybrida ◽  
Mda Content

Two cultivars of Freesia hybrida, ‘Shangnong Jinhuanghou’ and ‘Shangnong Hongtaige’, were used to study the respiration rate and physiological responses during flower development and senescence. Phenotypically, the vase life of ‘Shangnong Hongtaige’ was significantly shorter than that of ‘Shangnong Jinhuanghou’. At the whole flower level, both cultivars displayed similar change patterns on respiration rate. However, the change patterns in tepals, stamens, and pistils showed some differences in the two cultivars. A respiratory climacteric existed in most organs in both cultivars except for the stamen of ‘Shangnong Jinhuanghou’. During flower development and senescence, the levels of soluble proteins and soluble sugars were very high at early stages, followed by a dramatic decrease, and the lowest levels occurred in wilted tepals in both cultivars. Superoxide dismutase (SOD) activities increased slightly at early developmental stages followed by a constant decrease in two cultivars, and SOD activities in ‘Shangnong Jinhuanghou’ were significantly higher than those in ‘Shangnong Hongtaige’. Peroxidase activities showed a constant increase before tepals started wilting followed by a decrease in wilted tepals in both cultivars. In both cultivars, electrolytic leakage and malondialdehyde (MDA) content in tepals increased with the progression of development and senescence. MDA content in ‘Shangnong Hongtaige’ was much higher than that in ‘Shangnong Jinhuanghou’. These results indicated that the respiratory climacteric, the decrease of antioxidant enzyme activities, the peroxidation of membrane lipid, and the loss of soluble compounds could be considered as indicators of flower senescence in Freesia.

A Chlorophyll-Less Barley Mutant “NYB” Is Insensitive to Water Stress

2007 ◽  
Vol 62 (5-6) ◽  
pp. 403-409 ◽  
Author(s):  
Shu Yuan ◽  
Wen-Juan Liu ◽  
Tao Lei ◽  
Ming-Hua Luo ◽  
Jun-Bo Du ◽  
...  
Keyword(s):  
Water Stress ◽  
Maximum Efficiency ◽  
Photochemical Quenching ◽  
Wild Type ◽  
Energy Capture ◽  
Barley Mutant ◽  
Core Proteins ◽  
Psii Photochemistry ◽  
Non Photochemical Quenching ◽  
Quantum Yield Of Psii

“NYB” is a chlorophyll-less barley mutant, which grows relatively slow and unhealthily. The effects of water stress on photosystem II (PSII) of NYB and its wild type (WT) were investigated. Unexpected results indicated that the mutant was more resistant to water stress, because: PSII core proteins D1, D2 and LHCII declined more in WT than in NYB under water stress, and the corresponding psbA, psbD and cab mRNAs also decreased more dramatically in WT; CO2 assimilation, stomatal conductance, maximum efficiency of PSII photochemistry (Fv/Fm), efficiency of excitation energy capture by open PSII reaction centres (Fv’/Fm’), quantum yield of PSII electron transport (φPSII) and DCIP photoreduction in NYB were less sensitive to water stress than in WT, although the non-photochemical quenching coefficient (qN) and the photochemical quenching coefficient (qP) were almost the same in NYB and WT. Effective chlorophyll utilization and improved PSII protein formation in the mutant may be the reason for the enhanced stress resistance. Other possible mechanisms are also discussed.

scholarly journals γ-Aminobutyric Acid (GABA) Priming Improves Seed Germination and Seedling Stress Tolerance Associated With Enhanced Antioxidant Metabolism, DREB Expression, and Dehydrin Accumulation in White Clover Under Water Stress

2021 ◽  
Vol 12 ◽  
Author(s):  
Min Zhou ◽  
Muhammad Jawad Hassan ◽  
Yan Peng ◽  
Lin Liu ◽  
Wei Liu ◽  
...  
Keyword(s):  
Water Stress ◽  
Drought Stress ◽  
White Clover ◽  
Soluble Sugars ◽  
Aminobutyric Acid ◽  
Enzymatic Antioxidants ◽  
Antioxidant Metabolism ◽  
Limited Condition ◽  
The Impact ◽  
Seeds Germination

As an important plant growth regulator, the role of γ-aminobutyric acid (GABA) in regulating seeds germination was less well elucidated under water stress. The present study was conducted to investigate the impact of GABA pretreatment on seeds germination of white clover (Trifolium repens) under water deficient condition. Results demonstrated that seeds pretreated with 2μmol/l GABA significantly alleviated decreases in endogenous GABA content, germination percentage, germination potential, germination index, root length, and fresh weight along with marked reduction in mean germination time after 7days of germination under drought stress. In addition, seeds priming with GABA significantly increased the accumulation of soluble sugars, non-enzymatic antioxidants [reduced ascorbate, dehydroascorbic acid, oxidized glutathione (GSSG), and reduced glutathione (GSH)], and enzymes [superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), glutathioe reductase, and monodehydroasorbate reductase (MDHR)] activities involved in antioxidant metabolism, which could be associated with significant reduction in osmotic potential and the accumulation of superoxide anion, hydrogen peroxide, electrical leakage, and malondialdehyde in seeds under drought stress. The GABA-pretreated seeds exhibited significantly higher abundance of dehydrin (DHN, 56 KDa) and expression levels of DHNs encoding genes (SK2, Y2K, Y2SK, and Dehydrin b) and transcription factors (DREB2, DREB3, DREB4, and DREB5) than the untreated seeds during germination under water-limited condition. These results indicated that the GABA regulated improvement in seeds germination associated with enhancement in osmotic adjustment, antioxidant metabolism, and DREB-related DHNs expression. Current study will provide a better insight about the GABA-regulated defense mechanism during seeds germination under water-limited condition.

scholarly journals Growth Characteristics, Physiological and Metabolic Responses of Teak (Tectona Grandis Linn. f.) Clones Differing in Rejuvenation Capacity Subjected to Drought Stress

2010 ◽  
Vol 59 (1-6) ◽  
pp. 124-136 ◽  
Author(s):  
Azamal Husen
Keyword(s):  
Drought Stress ◽  
Electrolyte Leakage ◽  
Soluble Sugars ◽  
Photosynthetic Apparatus ◽  
Tectona Grandis ◽  
Field Capacity ◽  
Cellular Damage ◽  
Antioxidant Enzyme Activities ◽  
Significant Recovery ◽  
Mda Content

Summary Four-year old clones (FG1 and FG11) of teak (Tectona grandis Linn. f.), differing in rejuvenation capacity were grown in glazed earthenware pots. Drought treatments were imposed by withholding water for 20 days and rewatered to the field capacity daily for 5 days and the possible role of biochemical alteration and antioxidant metabolism in conferring photosynthetic capacity was determine by measuring photosynthetic traits, cellular damage and assaying activities of the superoxide dismutase (SOD) and peroxidase (PER) enzymes. Growth, relative water content (RWC), net photosynthetic rate (Pn), stomatal conductance (gs), chlorophyll fluorescence (Fv/Fm) and chlorophyll a, b, total chlorophyll and soluble protein content decreased significantly with increasing drought treatments from 5 to 20 days. Droughtinduced stress significantly increased the carotenoids content, relative electrolyte leakage and malondialdehyde (MDA) content, and, at the same time, accumulated free proline, free amino acid and soluble sugars in both clones. After re-watered to the field capacity daily for 5 days, both clones were shown significant recovery in the studied parameters. As compared with the FG11, the FG1 clone was more tolerant to drought as indicated by higher level of antioxidant enzyme activities as well as lower MDA content and electrolyte leakage. Similarly, drought stress caused less pronounced inhibition of Pn in FG1 than in FG11 clone. After re-hydration, the recovery was relatively quicker in FG1 than in FG11 clone. FG1 clone showed significant recovery in maximum quantum yield or photochemical efficiency of PSII (Fv/Fm) after 5 days of re-watering. The FG11 compared to the FG1, the former clone was less tolerant to drought than the latter. These results demonstrated that the different physiological strategies including antioxidative enzymes employed by the FG1 and FG11 clones of T. grandis to protect photosynthetic apparatus and alleviate drought stress. Furthermore, this study also provides ideas for teak improvement programmes and may be useful in breeding or genetic engineering for their tolerance to drought stress.

Effect of water stress and NaCl triggered changes on yield, physiology, biochemistry of broad bean (Vicia faba) plants and on quality of harvested pods

Biologia ◽  
2014 ◽  
Vol 69 (8) ◽  
Author(s):  
Georgia Ouzounidou ◽  
Ilias Ilias ◽  
Anastasia Giannakoula ◽  
Ioanna Theoharidou
Keyword(s):  
Water Stress ◽  
Field Experiments ◽  
Broad Bean ◽  
Foliar Application ◽  
Water Control ◽  
Simultaneous Exposure ◽  
Ameliorative Effect ◽  
Normal Water ◽  
The Impact

AbstractSalinity and drought are the most important abiotic stresses affecting crop yield. Broad bean was chosen as model plant for assessing the impact of salt stress and its interaction with drought in the field experiments. The factors examined in the experiments were the two irrigation rates (normal watering — NW with 3 L plant−1 and drought — D) and three salinity rates imposed by foliar application (0, 50, 100 mg L−1 NaCl). Highest NaCl level with normal water irrigation caused maximum reduction in plant height and production, which it was due to photosynthetic disturbances. Salt injuries were alleviated by increasing water stress. The control plants exposed to NaCl lost their ability over water control. The increased malondialdehyde (MDA) and H2O2 indicate the prevalence of oxidative stress due to salinity. The levels of proline and carbohydrates were higher under salinity alone than under simultaneous exposure to drought and NaCl. The protein concentration of immature and mature broad bean pods was more inhibited more by NaCl supply than by drought alone. The combination of drought and NaCl resulted in a significant increase in proteins, glucose, fructose and sucrose content. Overall, the ameliorative effect of drought under NaCl supply was quantified.

An increase in water deficit has no impact on the photosynthetic capacity of field-grown Mediterranean plants

2002 ◽  
Vol 29 (5) ◽  
pp. 621 ◽  
Author(s):  
Salvador Nogués ◽  
Leonor Alegre
Keyword(s):  
Water Deficit ◽  
Quantum Efficiency ◽  
Photosynthetic Capacity ◽  
Photosynthetic Parameters ◽  
Water Regimes ◽  
Relative Quantum ◽  
Mediterranean Plants ◽  
Psii Photochemistry ◽  
The Impact ◽  
Quantum Efficiency Of Psii

In the Mediterranean, annual mean precipitation has continuously decreased over the last three years (by ca 36% in Barcelona), and the decrease has been dramatic during the summer (by ca 78 and 64% during July and August, respectively). The impact of increased drought on the photosynthetic capacity of Mediterranean vegetation is currently unknown. In this study, two native Mediterranean plants [rosemary (Rosmarinus officinalis L.) and lavender (Lavandula stoechas L.)] were grown outdoors and subjected to two water regimes (50 mm month–1 during the summer, or no supplementary water at all). Rosemary and lavender plants watered with 50 mm month–1 during the summer had higher relative leaf water content and water potential than non-watered plants. Changes in water status were accompanied by large decreases in parameters of gas exchange [i.e. the light-saturated rate of CO2 assimilation, the maximum velocity of ribulose-1,5-bisphosphate (RuBP) carboxylation by Rubisco and the capacity for RuBP] and of modulated chlorophyll fluorescence (i.e. the relative quantum efficiency of PSII photochemistry and the efficiency of energy capture by open PSII reaction centres) during the summer, but no differences were found in any photosynthetic parameters for leaves subjected to the two water regimes. The drought-induced decreases in the relative quantum efficiency of PSII photochemistry in rosemary and lavender plants were attributable to ‘downregulation’ of electron transport. Photodamage to PSII in the field appeared to be a later effect of drought in these plants. Photorespiration was not a major mechanism protecting the photosynthetic apparatus of these plants from photodamage in the field. After the autumn rainfall, photosynthetic capacity fully recovered. We conclude that rosemary and lavender are well adapted to drought, and that an increase in water deficit is unlikely to have a significant impact on the photosynthetic capacity of leaves.

scholarly journals Effects of Pyruvate Supplementation on High-intensity Interval Exercise Induced Metabolic Acidosis and Repeated Sprint Exercise Performance of College Soccer Athletes

2021 ◽  
Author(s):  
yanping yang ◽  
Junqiang Qiu ◽  
Mengyue Wang ◽  
Lin Feng ◽  
Dan Luo ◽  
...  
Keyword(s):  
Metabolic Acidosis ◽  
High Intensity ◽  
Energy Contribution ◽  
Sprint Exercise ◽  
Interval Exercise ◽  
Repeated Sprint ◽  
Blood Ph ◽  
High Intensity Interval ◽  
The Impact ◽  
Oxidative System

Abstract Background: The effects of pyruvate on metabolic acidosis and oxidative metabolism had been studied. The ability to attenuate acidosis and improve oxidative system contribution are critical to the performance of team sport athletes during perform multiple high-intensity exercise over a limited period of time. This study aimed to investigate the impact of pyruvate supplementation on energy metabolism and metabolic acidosis during high-intensity interval exercise (HIIE), as well as to evaluate its role on repeated sprint exercise (RSE) performance.Methods: 14 well-trained male college soccer athletes (age: 20 ± 2 years, body fat: 13.11 ± 3.50 %) were studied in a randomized, double-blind, cross-over study. The participants ingested either 0.1g/kg/d of pyruvate or a placebo for 1-week. Metabolic acidosis was induced by HIIE after the supplement period, and RSE ability in the acidosis state was assessed. Venous blood pH, bicarbonate (HCO3-) and base excess (BE) were measured at baseline, pre-HIIE, post-HIIE, pre-RSE and post-RSE. Finger-stick blood lactate were collected at baseline, immediately after each bout of HIIE and 3, 5, 7, 10 min after HIIE. The energy systems contribution during HIIE were estimated. Results: Blood pH, HCO3- and BE were significantly lower than baseline after HIIE (p < 0.01) in both pyruvate group (PYR) and placebo group (PLA). Compared to PLA, the blood pH, HCO3- and BE were significantly improved in PYR at pre-HIIE (p < 0.01), post-HIIE (p < 0.01) and pre-RSE (p < 0.01). Furthermore, blood BE remained higher in PYR than PLA till end of RSE (p < 0.05). The contribution of oxidative system in the fourth bout of HIIE was higher in PYR than PLA (p < 0.05). In PLA, the ratio of total anaerobic energy contribution during HIIE was higher than that of aerobic (oxidative) (p < 0.01), but not in PYR (p > 0.05). Relative peak power (RPP) of first, fifth sprint, relative average power (RAP) of fifth sprint, the average of RPP and RAP during RSE were significantly improved in PYR compared with PLA (p < 0.05). While no significant changes in the PD% of each bout (p > 0.05) or average PD% (p > 0.05) were observed between the two groups. Conclusion: Pyruvate supplementation for 1-week enhances oxidative system energy contribution and buffers metabolic acidosis during HIIE, and improves RSE performance in acidosis.

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