scholarly journals Physiological and Biochemical Dissection Reveals a Trade-off Between Antioxidant Capacity and Heat Tolerance in Bread Wheat (Triticum aestivum L.)

Antioxidants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 351
Author(s):  
Mohammed Mohi-Ud-Din ◽  
Md. Nurealam Siddiqui ◽  
Md. Motiar Rohman ◽  
S.V. Krishna Jagadish ◽  
Jalal Uddin Ahmed ◽  
...  
Keyword(s):  
Heat Stress ◽  
Antioxidant Capacity ◽  
Heat Tolerance ◽  
Antioxidant Activities ◽  
Enzymatic Antioxidants ◽  
Wheat Seedlings ◽  
Trade Off ◽  
Biochemical Responses ◽  
Glutathione Cycle ◽  
Physiological And Biochemical

Heat stress alters photosynthetic components and the antioxidant scavenging system, negatively affecting plant growth and development. Plants overcome heat stress damage through an integrated network involving enzymatic and non-enzymatic antioxidants. This study aimed to assess physiological and biochemical responses in contrasting thermo-tolerant wheat varieties exposed to 25 °C (control) and 35 °C (heat stress), during the seedling stage. Our results revealed a substantial decrease in the photosynthetic pigments, carotenoids, anthocyanin content, and increased membrane injury index, malondialdehyde, methylglyoxal (MG), H2O2 contents and lipoxygenase activity compared to non-stress wheat seedlings. The heat-tolerant variety BARI Gom 26 (“BG26”) maintained higher cellular homeostasis compared to the heat susceptible variety Pavon 76 (“Pavon”), perpetuated by higher accumulation of proline, glycine betaine, ascorbate-glutathione cycle associated enzymes, reduced glutathione and ascorbate concentration in plant cells. Significantly lower levels of MG detoxification and antioxidant activities and ascorbate-glutathione cycle-related enzymatic activities lead to increased susceptibility in variety “Pavon”. Hierarchical clustering and principal component analysis revealed that variety “BG26” possess a combination of biochemical responses tailoring antioxidant activities that induced a higher level of tolerance. Taken together, our results provide a pipeline for establishing a trade-off between antioxidant capacity and heat tolerance to facilitate functional genomics and translational research to unravel underlying mechanisms to better adapt wheat to heat stress.

scholarly journals Melatonin alleviates heat-induced damage of tomato seedlings by balancing redox homeostasis and modulating polyamine and nitric oxide biosynthesis

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Mohammad Shah Jahan ◽  
Sheng Shu ◽  
Yu Wang ◽  
Zheng Chen ◽  
Mingming He ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Nitric Oxide ◽  
Hydrogen Peroxide ◽  
Heat Stress ◽  
Heat Shock ◽  
Defense Mechanism ◽  
Enzymatic Antioxidants ◽  
Tomato Seedlings ◽  
Glutathione Cycle

Abstract Background Melatonin is a pleiotropic signaling molecule that plays multifarious roles in plants stress tolerance. The polyamine (PAs) metabolic pathway has been suggested to eliminate the effects of environmental stresses. However, the underlying mechanism of how melatonin and PAs function together under heat stress largely remains unknown. In this study, we investigated the potential role of melatonin in regulating PAs and nitric oxide (NO) biosynthesis, and counterbalancing oxidative damage induced by heat stress in tomato seedlings. Results Heat stress enhanced the overproduction of reactive oxygen species (ROS) and damaged inherent defense system, thus reduced plant growth. However, pretreatment with 100 μM melatonin (7 days) followed by exposure to heat stress (24 h) effectively reduced the oxidative stress by controlling the overaccumulation of superoxide (O2•−) and hydrogen peroxide (H2O2), lowering the lipid peroxidation content (as inferred based on malondialdehyde content) and less membrane injury index (MII). This was associated with increased the enzymatic and non-enzymatic antioxidants activities by regulating their related gene expression and modulating the ascorbate–glutathione cycle. The presence of melatonin induced respiratory burst oxidase (RBOH), heat shock transcription factors A2 (HsfA2), heat shock protein 90 (HSP90), and delta 1-pyrroline-5-carboxylate synthetase (P5CS) gene expression, which helped detoxify excess ROS via the hydrogen peroxide-mediated signaling pathway. In addition, heat stress boosted the endogenous levels of putrescine, spermidine and spermine, and increased the PAs contents, indicating higher metabolic gene expression. Moreover, melatonin-pretreated seedlings had further increased PAs levels and upregulated transcript abundance, which coincided with suppression of catabolic-related genes expression. Under heat stress, exogenous melatonin increased endogenous NO content along with nitrate reductase- and NO synthase-related activities, and expression of their related genes were also elevated. Conclusions Melatonin pretreatment positively increased the heat tolerance of tomato seedlings by improving their antioxidant defense mechanism, inducing ascorbate–glutathione cycle, and reprogramming the PAs metabolic and NO biosynthesis pathways. These attributes facilitated the scavenging of excess ROS and increased stability of the cellular membrane, which mitigated heat-induced oxidative stress.

scholarly journals Physiological and Biochemical Responses of Two Cotton (Gossypium hirsutum L.) Cultivars Differing in Thermotolerance to High Night Temperatures during Anthesis

Agriculture ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 407
Author(s):  
Dimitra A. Loka ◽  
Derrick M. Oosterhuis
Keyword(s):  
Cell Membrane ◽  
Heat Tolerance ◽  
Crop Production ◽  
Membrane Integrity ◽  
Photosynthetic Rates ◽  
Cell Membrane Integrity ◽  
Biochemical Responses ◽  
Heat Tolerant ◽  
Physiological And Biochemical ◽  
Carbohydrate Contents

Heat stress constitutes a major threat to crop production, and according to climatic projections, night temperatures are expected to increase faster and to a greater extent compared to day temperatures. While extensive research has been dedicated to the effects of higher than optimum day temperatures on cotton physiology, metabolism, and yield, and while heat-tolerant cotton cultivars have been introduced, the responses of such heat-tolerant cultivars to high night temperatures have not been evaluated. The objective of this study was to assess the efficiency of heat-tolerant cultivars to high night temperatures stress by monitoring the physiological and biochemical responses of two cotton cultivars, differing in thermotolerance, subjected to higher than optimum night temperatures, during anthesis. To that end, growth chamber experiments were conducted using two cotton cultivars differing in thermotolerance, namely ST5288B2RF (thermosensitive) and VH260 (thermotolerant). Treatments consisted of normal day/night temperatures (32/24 °C) and high night temperatures (32/30 °C) for 2 weeks at flowering (approximately 8 eight weeks after planting). The results indicated that VH260 was more thermotolerant than ST5288 even under conditions of high night temperature stress, as it managed to maintain its net photosynthetic rates, cell membrane integrity, as well as pistil carbohydrate contents and ultimately achieved higher total reproductive weight. It was concluded that heat tolerance of thermotolerant cultivars selected under conditions of high day temperatures is also conserved under high night temperatures, while net photosynthetic rates and cell membrane integrity can be utilized as selection traits for heat tolerance under either high day or night temperatures.

scholarly journals Comparative Studies on the Physiological and Biochemical Responses to Salt Stress of Eggplant (Solanum melongena) and Its Rootstock S. torvum

Agriculture ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 328
Author(s):  
Marco Brenes ◽  
Jason Pérez ◽  
Sara González-Orenga ◽  
Andrea Solana ◽  
Monica Boscaiu ◽  
...  
Keyword(s):  
Salt Tolerance ◽  
Specific Activity ◽  
Soluble Sugars ◽  
Solanum Melongena ◽  
High Salt ◽  
Total Phenolic ◽  
Antioxidant Compounds ◽  
Enzymatic Antioxidants ◽  
Biochemical Responses ◽  
Physiological And Biochemical

This study investigated the physiological and biochemical responses to salinity stress of Solanum melongena and its wild relative, Solanum torvum, commonly used as eggplant rootstock. Young plants of both species were watered during 25 days with NaCl aqueous solutions at the following four final concentrations: 0 (for the controls), 100, 200, and 300 mM. Plant growth parameters, photosynthetic pigments content, monovalent ion concentrations in roots and leaves, leaf levels of osmolytes (proline and total soluble sugars), oxidative stress markers (MDA and H2O2), non-enzymatic antioxidants (total phenolic compounds and total flavonoids), and enzymatic antioxidant activities (superoxide dismutase, catalase, glutathione reductase) were determined after the stress treatments. Salt-induced growth reduction was more significant in S. melongena than in S. torvum, especially at high salt concentrations, indicating a (slightly) higher salt tolerance of the wild species. The mechanisms of tolerance of S. torvum were partly based on the active transport of toxic ions to the leaves at high external salinity and, presumably, a better capacity to store them in the vacuoles, as well as on the accumulation of proline to higher concentrations than in the cultivated eggplant. MDA and H2O2 contents did not vary in response to the salt treatments in S. torvum. However, in S. melongena, MDA content increased by 78% when 300 mM NaCl was applied. No activation of antioxidant mechanisms, accumulation of antioxidant compounds, or increase in the specific activity of antioxidant enzymes in any of the studied species was induced by salinity. The relatively high salt tolerance of S. torvum supports its use as rootstock for eggplant cultivation in salinized soils and as a possible source of salt-tolerance genes for the genetic improvement of cultivated eggplant.

scholarly journals Differences in Thermoregulatory Responses between Dorper and Second Cross Lambs to Heat Stress Challenges

Proceedings ◽  
2020 ◽  
Vol 36 (1) ◽  
pp. 155 ◽  
Author(s):  
Aleena Joy ◽  
Frank R. Dunshea ◽  
Brain J. Leury ◽  
Kristy DiGiacomo ◽  
Iain J. Clarke ◽  
...  
Keyword(s):  
Heat Stress ◽  
Environmental Temperature ◽  
Base Excess ◽  
Physiological Responses ◽  
Blood Electrolytes ◽  
Biochemical Responses ◽  
Breed Differences ◽  
Cyclic Heat ◽  
Lactate Levels ◽  
Physiological And Biochemical

We compared the thermotolerance of Dorper (D) and second cross (SC) (Poll Dorset x Merino/Border Leicester) lambs by assessing physiological and biochemical responses. After acclimatization, 4–5 month old lambs of each breed were exposed to either thermo-neutral (18 °C–21 °C, 40%–50% RH, n = 12/group) or cyclic heat stress (HS) (28 °C–40 °C; 40%–60% RH, n = 12/group) for 2 weeks in climatic chambers. The HS involved exposure to temperatures of 38 °C–40 °C between 0800 and 17.00 h daily; otherwise the temperature was maintained at 28 °C. Elevated temperature increased rectal temperature (p < 0.01), respiration rate (p < 0.01) and skin temperature (p < 0.01) in both breeds, (data for 12.00 and 16.00 h pooled), but to a lesser extent in D than in SC lambs (p < 0.01). The HS increased (p < 0.01) water intake to a greater extent in SC than in D lambs and HS reduced (p < 0.05) food intake in SC lambs but not in D lambs. There were no treatment effects on blood glucose and lactate levels in either breed. Significant effects of breed (p < 0.01) and treatment (p < 0.01) were observed in blood creatinine levels, being higher in SC lambs. Higher pH (p < 0.01) and lower pCO2 (p < 0.01) were recorded under HS in both breeds. Among blood electrolytes, Cl−, Na+ and base excess were significantly (all p < 0.01) reduced under HS, with no breed differences. In conclusion, the attenuated physiological responses to HS in Dorper lambs indicates better adaptation of this breed to high environmental temperature.

scholarly journals The Effect of Exogenous Application of Quercetin Derivative Solutions on the Course of Physiological and Biochemical Processes in Wheat Seedlings

2021 ◽  
Vol 22 (13) ◽  
pp. 6882
Author(s):  
Marta Jańczak-Pieniążek ◽  
Dagmara Migut ◽  
Tomasz Piechowiak ◽  
Jan Buczek ◽  
Maciej Balawejder
Keyword(s):  
Gas Exchange ◽  
Antioxidant Capacity ◽  
Chlorophyll Content ◽  
Total Antioxidant Capacity ◽  
Total Phenolic ◽  
Chlorophyll Content And Fluorescence ◽  
Wheat Seedlings ◽  
Physiological Processes ◽  
Total Antioxidant ◽  
Physiological And Biochemical

Quercetin, classified as a flavonoid, is a strong antioxidant that plays a significant role in the regulation of physiological processes in plants, which is particularly important in the case of biotic and abiotic stresses. The study investigated the effect of the use of potassium quercetin solutions in various concentrations (0.5%, 1.0%, 3.0% and 5.0%) on the physiological and biochemical properties of wheat seedlings. A pot experiment was carried out in order to determine the most beneficial dose of this flavonoid acting as a bio-stimulant for wheat plants. Spraying with quercetin derivative solutions was performed twice, and physiological measurements (chlorophyll content and fluorescence as well as gas exchange) were carried out on the first and seventh days after each application. The total phenolic compounds content and the total antioxidant capacity were also determined. It was shown that the concentrations of potassium quercetin applied have a stimulating effect on the course of physiological processes. In the case of most of the tested physiological parameters (chlorophyll content and fluorescence and gas exchange) and the total antioxidant capacity, no significant differences were observed in their increase as a result of application with concentrations of 3.0 and 5.0%. Therefore, the beneficial effect of quercetin on the analysed parameters is already observed when spraying with a concentration of 3.0%.

scholarly journals Temperature Stress Induced Antioxidative and Biochemical Changes in Wheat (Triticum aestivum L.) Cultivars

2016 ◽  
Vol 2 ◽  
pp. 22 ◽  
Author(s):  
Jayanwita Sarkar ◽  
Bishwanath Chakraborty ◽  
Usha Chakraborty
Keyword(s):  
Heat Stress ◽  
Antioxidative Enzymes ◽  
Peroxidase Activity ◽  
Triticum Aestivum L ◽  
Membrane Lipid ◽  
Enzymatic Antioxidants ◽  
Wheat Seedlings ◽  
Different Temperatures ◽  
Heat Susceptibility Index ◽  
Cellular Compartments

<span lang="EN-IN">The aim of this study is to understand the effect of elevated temperature on wheat seedlings of four cultivars, Gayetri (GY), Gandhari (GN), Kedar (KD), PBW343 in terms of  tolerance/susceptibility , along with antioxidative and biochemical responses. For this, seedlings of four cultivars were exposed to different temperatures ranging from 25-40<sup>0</sup>C for six hours. According to heat susceptibility index calculated GN was found to be heat tolerant, PBW343 heat sensitive and the other two, GY and KD moderately tolerant.  Exposure to high temperature led to gradual increase in membrane lipid peroxidation and hydrogen peroxide accumulation. H<sub>2</sub>O<sub>2</sub> and malonaldehyde accumulated to much higher amount in leaf tissues of PBW343 and GY than GN and KD. Among antioxidative enzymes, catalase, glutathione reductase and ascorbate peroxidase activity initially increased at 35<sup>0</sup>C, followed by reduced activity under heat stress in all cultivars. However, peroxidase activity continued to increase under heat stress. Total chlorophyll and non enzymatic antioxidant carotenoids, initially increased upto 30<sup>0</sup>C, following which there was gradual decrease in these components. Compatible osmolytes - proline and total sugar level within cellular compartments were enhanced upto 35<sup>0</sup>C. Results suggested that wheat can endure heat induced oxidative stress up to certain period, manifested by elevation of non enzymatic antioxidants and osmo protectants, as well as upregulation of antioxidative enzymes.</span>

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