scholarly journals Effects of salt stress on physiological and biochemical responses of three maize genotypes at the early seedling stage

2021 ◽  
Vol 117 (1) ◽  
pp. 1
Author(s):  
Ali DOĞRU
Keyword(s):  
Salt Stress ◽  
Crop Productivity ◽  
Antioxidant Systems ◽  
Enzymatic Antioxidants ◽  
Sod Activity ◽  
Oxidative Markers ◽  
Maize Genotypes ◽  
Stress Changes ◽  
Relative Water ◽  
Glutathione Cycle

<p>Salt stress is one of the major global problems for crop productivity in the arid and semi-arid regions of the world. In this study, variations in some physiological parameters, water relations, and antioxidant systems under salinity (300 mM NaCl) among three maize (<em>Zea mays</em> L.) genotypes (‘P3167’, ‘32K61’, and ‘Bora’) were investigated. Our result indicated that shoot growth is more sensitive to salinity as compared to root growth. Salt stress led to physiological drought in all maize genotypes as indicated by the significant decrease in relative water content and increase in water deficit index. Salt stress increased SOD activity in all genotypes showing an efficient formation and detoxification of superoxide radical. The constant level of oxidative markers (MDA and H<sub>2</sub>O<sub>2</sub>) and the increased level of the reduced ascorbate and phenolic may indicate that non-enzymatic antioxidants are responsible for the elimination of oxidative stress. Changes in ascorbate peroxidase and glutathione reductase activities under salinity demonstrated a functional failure in the ascorbate-glutathione cycle, especially in ‘P3167’ and ‘32K61’. Based on the presented results we may conclude that the genotype ‘Bora’ is tolerant to salinity while ‘P3167’ and ‘32K61’ are sensitive. </p>

scholarly journals Assessment of Morpho-Physiological, Biochemical and Antioxidant Responses of Tomato Landraces to Salinity Stress

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 696
Author(s):  
Reem H. Alzahib ◽  
Hussein M. Migdadi ◽  
Abdullah A. Al Ghamdi ◽  
Mona S. Alwahibi ◽  
Abdullah A. Ibrahim ◽  
...  
Keyword(s):  
Salt Stress ◽  
Salinity Stress ◽  
Dry Weight ◽  
Proline Content ◽  
Enzymatic Antioxidants ◽  
Sod Activity ◽  
Carotene Content ◽  
Antioxidants Activity ◽  
Solanum Lycopersicum L ◽  
Salinity Levels

Understanding salt tolerance in tomato (Solanum lycopersicum L.) landraces will facilitate their use in genetic improvement. The study assessed the morpho-physiological variability of Hail tomato landraces in response to different salinity levels at seedling stages and recommended a tomato salt-tolerant landrace for future breeding programs. Three tomato landraces, Hail 548, Hail 747, and Hail 1072 were tested under three salinity levels: 75, 150, and 300 mM NaCl. Salinity stress reduced shoots’ fresh and dry weight by 71% and 72%, and roots were 86.5% and 78.6%, respectively. There was 22% reduced chlorophyll content, carotene content by 18.6%, and anthocyanin by 41.1%. Proline content increased for stressed treatments. The 300 mM NaCl treatment recorded the most proline content increases (67.37 mg/g fresh weight), with a percent increase in proline reaching 61.67% in Hail 747. Superoxide dismutase (SOD) activity decreased by 65% in Hail 548, while it relatively increased in Hail 747 and Hail 1072 treated with 300 mM NaCl. Catalase (CAT) activity was enhanced by salt stress in Hail 548 and recorded 7.6%, increasing at 75 and 5.1% at 300 mM NaCl. It revealed a reduction in malondialdehyde (MDA) at the 300 mM NaCl concentration in both Hail 548 and Hail 1072 landraces. Increasing salt concentrations showed a reduction in transpiration rate of 70.55%, 7.13% in stomatal conductance, and 72.34% in photosynthetic rate. K+/Na+ ratios decreased from 56% for 75 mM NaCl to 85% for 300 mM NaCl treatments in all genotypes. The response to salt stress in landraces involved some modifications in morphology, physiology, and metabolism. The landrace Hail 548 may have better protection against salt stress and observed protection against reactive oxygen species (ROS) by increasing enzymatic “antioxidants” activity under salt stress.

scholarly journals 24-Epibrassinolide (EBR) Confers Tolerance against NaCl Stress in Soybean Plants by Up-Regulating Antioxidant System, Ascorbate-Glutathione Cycle, and Glyoxalase System

Biomolecules ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 640 ◽  
Author(s):  
Alam ◽  
Albalawi ◽  
Altalayan ◽  
Bakht ◽  
Ahanger ◽  
...  
Keyword(s):  
Salt Stress ◽  
Nacl Stress ◽  
Enzymatic Antioxidants ◽  
Oxidative Stress Biomarkers ◽  
Gas Exchange Parameters ◽  
Stress Biomarkers ◽  
Soybean Plants ◽  
Glutathione Cycle ◽  
Na Uptake ◽  
Glyoxalase Cycle

: The present research was performed to assess the effect of 24-epibrassinolide (EBR) on salt-stressed soybean plants. Salt stress suppressed growth, biomass yield, gas exchange parameters, pigment content, and chlorophyll fluorescence, but all these parameters were up-regulated by EBR supply. Moreover, salt stress increased hydrogen peroxide, malondialdehyde, and electrolyte leakage. EBR supplementation reduced the accumulation of oxidative stress biomarkers. The activities of superoxide dismutase and catalase, and the accumulation of proline, glycinebetaine, total phenols, and total flavonoids increased with NaCl stress, but these attributes further increased with EBR supplementation. The activities of enzymes and the levels of non-enzymatic antioxidants involved in the Asc-Glu cycle also increased with NaCl stress, and further enhancement in these attributes was recorded by EBR supplementation. Salinity elevated the methylglyoxal content, but it was decreased by the EBR supplementation accompanying with up-regulation of the glyoxalase cycle (GlyI and GlyII). Salinity enhanced the Na+ uptake in root and shoot coupled with a decrease in uptake of Ca2+, K+, and P. However, EBR supplementation declined Na+ accumulation and promoted the uptake of the aforementioned nutrients. Overall, EBR supplementation regulated the salt tolerance mechanism in soybean plants by modulating osmolytes, activities of key enzymes, and the levels of non-enzymatic antioxidants.

scholarly journals The Apoplastic and Symplastic Antioxidant System in Onion: Response to Long-Term Salt Stress

Antioxidants ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 67 ◽  
Author(s):  
Grisaly García ◽  
María José Clemente-Moreno ◽  
Pedro Díaz-Vivancos ◽  
Marina García ◽  
José Antonio Hernández
Keyword(s):  
Salt Stress ◽  
Redox State ◽  
Reduced Glutathione ◽  
Membrane Integrity ◽  
Monodehydroascorbate Reductase ◽  
Antioxidant Systems ◽  
Lower Sensitivity ◽  
Sod Activity ◽  
Leaf Tissues

The response of apoplastic antioxidant systems in root and leaf tissues from two onion genotypes (‘Texas 502’, salt-sensitive and ‘Granex 429’, salt-resistant) in response to salinity was studied. Electrolyte leakage data indicated the membrane integrity impairing by the effect of salts, especially in ‘Texas 502’. We detected superoxide dismutase (SOD) and peroxidase (POX) activity in the root and leaf apoplastic fractions from onion plants. Salinity increased SOD activity in the root symplast of ‘Texas 502’ and in ‘Granex 429’ leaves. In contrast, salinity reduced SOD activity in the leaf and root apoplastic fractions from ‘Texas 502’. In ‘Granex 429’, salt-stress increased leaf apoplastic POX activity and symplastic catalase (CAT) activity of both organs, but a decline in root apoplastic POX from ‘Texas 502’ took place. Salt-stress increased monodehydroascorbate reductase (MDHAR) in root and leaf symplast and in root glutathione reductase GR, mainly in ‘Granex 429’, but only in this genotype, leaf dehydroascorbate reductase (DHAR) activity increased. In contrast, a decline in leaf GR was produced only in ‘Texas 502’. Salinity increased leaf ASC levels, and no accumulation of dehydroascorbate (DHA) was observed in roots in both cases. These responses increased the redox state of ascorbate, especially in roots. In contrast, salinity declined reduced glutathione (GSH), but oxidised glutathione (GSSG) was accumulated in leaves, decreasing the redox state of glutathione. Salinity slightly increased root GSH concentration in the salt-tolerant genotype and was unchanged in the salt-sensitive genotype, but no accumulation of GSSG was produced, favoring the rise and/or maintenance of the redox state of the glutathione. These results suggest that the lower sensitivity to salt in ‘Granex 429’ could be related to a better performance of the antioxidant machinery under salinity conditions.

scholarly journals Maize Grain Extract Enriched with Polyamines Alleviates Drought Stress in Triticum aestivum through Up-Regulation of the Ascorbate-Glutathione Cycle, Glyoxalase System, and Polyamine Gene Expression

Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 949
Author(s):  
Hesham F. Alharby ◽  
Hassan S. Al-Zahrani ◽  
Yahya M. Alzahrani ◽  
Hameed Alsamadany ◽  
Khalid R. Hakeem ◽  
...  
Keyword(s):  
Water Content ◽  
Relative Water Content ◽  
Photosynthetic Efficiency ◽  
Membrane Stability ◽  
Severe Drought ◽  
Enzymatic Antioxidants ◽  
Glyoxalase System ◽  
Relative Water ◽  
Moderate Drought ◽  
Glutathione Cycle

The potential protective role of priming wheat seeds with maize green extract (MGE) against the stress effects of drought was studied. Pretreatment using MGE, MGE enriched with polyamines (MGEPA), and drought treatments (irrigation deficit of 30% (severe drought) or 60% (moderate drought) versus 90% relative water content of soil as a control) were applied in a factorial completely randomized design. Under moderate drought, pretreatment with MGEPA outperformed MGE and control, while severely stressed plants died even with pretreatments. Both extracts enhanced normal plant growth and yield and mitigated the deleterious effect of moderately stressed plants. Application of both extracts markedly increased photosynthetic efficiency, membrane stability, relative water content, and accumulation of antioxidants, osmoprotectants, trans- and cis-zeatin, polyamines, and their gene expressions, while levels of superoxide (O2•‒) and hydrogen peroxide (H2O2), lipid peroxidation, and electrolyte leakage were decreased. Enzymatic antioxidants and glyoxalase system activities were improved in moderately stressed plants and were further improved with pretreatment with both extracts, thus protecting plants from oxidative damage by up-regulation of the ascorbate–glutathione cycle. Glycine betaine, soluble sugars, and proline levels were greatly increased in pretreated plants, thus maintaining membrane stability and photosynthetic efficiency. The interaction between drought and pretreatment using MGEPA was significant in growing wheat plants in dry environments with 60% relative water content of soil.

scholarly journals Regulation of enzymatic and non-enzymatic antioxidants contributes to salt tolerance in hitherto unknown upland farmer rice varieties.

2020 ◽  
pp. 18-27
Author(s):  
Lins Simon ◽  
Yusuf Akkara
Keyword(s):  
Salt Stress ◽  
Salt Tolerance ◽  
Stability Index ◽  
Monodehydroascorbate Reductase ◽  
Enzymatic Antioxidants ◽  
Salt Tolerant ◽  
Sod Activity ◽  
Rice Varieties ◽  
Pronounced Increase ◽  
Nacl Concentration

Salt tolerance potential of the three upland farmer varieties, koduvelliyan, mullankayama and marathondi was evaluated by comparing with the released salt-tolerant pokkali variety, vytilla-2. The salt tolerance exhibited by the upland varieties was identical with the salt tolerant variety. The superoxide (O2-) content in the upland varieties was lower; however, the hydrogen peroxide (H2O2) content increased with the salt concentration. The lesser malondialdehyde (MDA) content in the koduvelliyan variety was equivalent to the vytilla-2 and slight increase was observed in mullankayama and marathondi. The ascorbate (AsA) content in the upland varieties was comparable to vytilla-2 and upon exposure to increased concentration of NaCl, the AsA level reduced in all the treatments. Reduced glutathione (GSH) content was uniform in all the varieties up to a concentration of 100mM NaCl, however, in 125-150mM NaCl, mullankayama showed a pronounced increase in GSH content. Under salt stress, due to the formation of O2-, the oxidation of GSH was higher, maintaining a stable GSH/GSSG ratio. Superoxide dismutase (SOD) and catalase (CAT) activity of the upland varieties was higher than vytilla-2 up to 100mM NaCl, however, in 125-150mM NaCl the SOD activity increased slightly and the CAT activity decreased. Ascorbate peroxidase (APX) activity increased in upland varieties up to 125mM NaCl, and in 150mM NaCl, maintained a steady level in all the varieties. Glutathione reductase (GR) activity increased proportionate with NaCl concentration; with highest activity in all the upland varieties. Monodehydroascorbate reductase (MDHAR) activity was uniform in all the varieties up to 100mM NaCl, however, in 125 and 150mM NaCl, vytilla-2 showed higher MDHAR activity. Dehydroascorbate reductase (DHAR) activity was lesser in upland varieties under salt stress compared to vytilla-2. The GSH/GSSG ratio decreased in marathondi and koduvelliyan varieties with the increase in NaCl concentration, however, in mullankayama and vytilla-2, the GSH/GSSG ratio was higher. The membrane stability index of all the varieties was uniform in all the concentrations of NaCl used, except marathondi. The Na+ content in all the varieties increased in relation to NaCl concentration and the K+ efflux was higher suggesting a higher Na+/K+ ratio, with increased NaCl concentration.

scholarly journals Effects of salt stress on antioxidant and ascorbate glutathione cycle enzyme activities in Pokkali rice varieties – Vytilla 1-9

2020 ◽  
Vol 7 (3) ◽  
pp. 341-348
Author(s):  
Lins Simon ◽  
Akkara Yusuf
Keyword(s):  
Salt Stress ◽  
Specific Activity ◽  
Positive Control ◽  
Negative Control ◽  
Enzymatic Antioxidants ◽  
Ros Scavenging ◽  
Rice Varieties ◽  
Cycle Enzyme ◽  
H2o2 Content ◽  
Glutathione Cycle

The enzymatic and non-enzymatic antioxidant levels in the released salt tolerant Pokkali, (vytilla, VTL 1-9) varieties were studied under different NaCl concentrations (0-150 mM NaCl). The specific activity of superoxide dismutase (SOD), catalase (CAT) and ascorbate-glutathione cycle enzymes and non-enzymatic antioxidants like superoxide (O2-), hydrogen peroxide (H2O2), malondialdehyde (MDA), glutathione (GSH) and ascorbic acid (AsA) was determined in plants exposed to salt stress. IR-28 was used as positive control and the VTL varieties were used as negative control. The H2O2 and superoxide (O2-) contents were higher in IR-28 at all the applied concentrations of NaCl. The VTL varieties without salt treatment did not evoke any response substantiating the role of salt priming in antioxidant signalling. The MDA contents were higher in the positive and negative control. MDA content was reduced in the NaCl treated VTL varieties. In the positive and negative control varieties, the quantity of ascorbate and glutathione contents were lesser and upregulated in salt treated VTL varieties. Highest H2O2 content was observed in 150 mM NaCl treatment. The H2O2 contents decreased with the increase in all concentrations of NaCl and lowest H2O2 contents was observed in VTL-1 and highest in VTL-2 and VTL-8 treated with 150 mM NaCl. Superoxide contents varied in all the nine varieties depending on the salt concentration. The SOD levels in all the varieties showed a positive correlation with the superoxide and H2O2 content. Lesser quantities of SOD, CAT and the ascorbate - glutathione cycle enzymes were expressed in the positive and negative control. The increased NaCl concentration (25-150 mM) upregulated antioxidant and ascorbate-glutathione cycle enzymes in the VTL varieties. The APX activity was lower in the control and salt treated plants. The GR activity increased linearly in all the varieties with respect to salt concentrations. The MDHAR and DHAR activities showed marginally linear increase, with all concentrations of NaCl. The APX activity was similar or lower to MDHAR activity while DHAR activity was similar to MDHAR activity. The results of the present study reveals the higher levels of enzymatic and non-enzymatic antioxidants under salt stress reflect the salt tolerance potential of pokkali varieties mediated by the up regulation of ROS scavenging enzymes.

scholarly journals Biochemical and molecular changes in buckwheat leaves during exposure to salt stress

2011 ◽  
Vol 63 (1) ◽  
pp. 67-77 ◽  
Author(s):  
Z.S. Jovanovic ◽  
Vesna Maksimovic ◽  
Svetlana Radovic
Keyword(s):  
Lipid Peroxidation ◽  
Salt Stress ◽  
Stress Tolerance ◽  
Abiotic Stress Tolerance ◽  
Stress Sensitivity ◽  
Molecular Response ◽  
Stress Changes ◽  
Relative Water ◽  
Short And Long Term

In spite of the great nutritive and pharmacological potentials of buckwheat, data about the abiotic stress tolerance of this plant species are very limited. The aim of this work was to analyze the biochemical and molecular response of buckwheat plants in the middle vegetative phase against short- and long-term salt stress. Changes in relative water content, level of lipid peroxidation, content and localization of H2O2 as well as changes in antioxidative enzyme activity and expression of ubiquitin and dehydrins, were investigated. Reasons for observed buckwheat salt stress sensitivity as well as possibilities for enhancing stress tolerance are discussed.

scholarly journals Sequential Application of Antioxidants Rectifies Ion Imbalance and Strengthens Antioxidant Systems in Salt-Stressed Cucumber

Plants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1783
Author(s):  
Mahmoud F. Seleiman ◽  
Wael M. Semida ◽  
Mostafa M. Rady ◽  
Gamal F. Mohamed ◽  
Khaulood A. Hemida ◽  
...  
Keyword(s):  
Photosynthetic Efficiency ◽  
Antioxidant Defense ◽  
Growth Traits ◽  
Stability Index ◽  
Growth Characteristics ◽  
Antioxidant Systems ◽  
Enzymatic Antioxidants ◽  
Relative Water ◽  
Ion Imbalance ◽  
Sequential Treatments

Exogenous antioxidant applications enable salt-stressed plants to successfully cope with different environmental stresses. The objectives of this investigation were to study the effects of sequential treatments of proline (Pro), ascorbic acid (AsA), and/or glutathione (GSH) on 100 mM NaCl-stressed cucumber transplant’s physio-biochemical and growth traits as well as systems of antioxidant defense. Under salinity stress, different treatment of AsA, Pro, or/and GSH improved growth characteristics, stomatal conductance (gs), enhanced the activities of glutathione reductase (GR), superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT) as well as increased contents of AsA, Pro, and GSH. However, sequential application of antioxidants (GSH-Pro- AsA) significantly exceeded all individual applications, reducing leaf and root Cd2+ and Na+ contents in comparison to the control. In plants grown under NaCl-salt stress, growth characteristics, photosynthetic efficiency, membrane stability index (MSI), relative water content (RWC), contents of root and leaf K+ and Ca2+, and ratios of K+/Na+ and Ca2+/Na+ were notably reduced, while leaf contents of non-enzymatic and enzymatic antioxidants, as well as root and leaf Cd2+ and Na+ concentrations were remarkably increased. However, AsA, Pro, or/and GSH treatments significantly improved all investigated growth characteristics, photosynthetic efficiency, RWC and MSI, as well as AsA, Pro, and GSH, and enzymatic activity, leaf and root K+ and Ca2+ contents and their ratios to Na+, while significantly reduced leaf and root Cd2+ and Na+ contents.

scholarly journals Mitochondrial redox systems as central hubs in plant metabolism and signalling

2021 ◽  
Author(s):  
Olivier Van Aken
Keyword(s):  
Stress Responses ◽  
Plant Mitochondria ◽  
Nuclear Gene ◽  
Tca Cycle ◽  
Cellular Damage ◽  
Future Research ◽  
Antioxidant Systems ◽  
Plant Metabolism ◽  
Redox Systems ◽  
Glutathione Cycle

Abstract Plant mitochondria are indispensable for plant metabolism and are tightly integrated into cellular homeostasis. This review provides an update on the latest research concerning the organisation and operation of plant mitochondrial redox systems, and how they affect cellular metabolism and signalling, plant development and stress responses. New insights into the organisation and operation of mitochondrial energy systems such as the tricarboxylic acid (TCA) cycle and mitochondrial electron chain (mtETC) are discussed. The mtETC produces reactive oxygen and nitrogen species, which can act as signals or lead to cellular damage, and are thus efficiently removed by mitochondrial antioxidant systems, including Mn-superoxide dismutase, ascorbate-glutathione cycle and thioredoxin-dependent peroxidases. Plant mitochondria are tightly connected with photosynthesis, photorespiration and cytosolic metabolism, thereby providing redox-balancing. Mitochondrial proteins are targets of extensive post-translational modifications, but their functional significance and how they are added or removed remains unclear. To operate in sync with the whole cell, mitochondria can communicate their functional status via mitochondrial retrograde signalling to change nuclear gene expression, and several recent breakthroughs here are discussed. At a whole organism level, plant mitochondria thus play crucial roles from the first minutes after seed imbibition, supporting meristem activity, growth and fertility, until senescence of darkened and aged tissue. Finally, plant mitochondria are tightly integrated with cellular and organismal responses to environmental challenges such as drought, salinity, heat and submergence, but also threats posed by pathogens. Both the major recent advances and outstanding questions are reviewed, which may help future research efforts on plant mitochondria.

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