Kamrun Nahar - Academia.edu (original) (raw)

Papers by Kamrun Nahar

Research paper thumbnail of Supplemental Selenium and Boron Mitigate Salt-Induced Oxidative Damages in Glycine max L

Plants

The present investigation was executed with an aim to evaluate the role of exogenous selenium (Se... more The present investigation was executed with an aim to evaluate the role of exogenous selenium (Se) and boron (B) in mitigating different levels of salt stress by enhancing the reactive oxygen species (ROS) scavenging, antioxidant defense and glyoxalase systems in soybean. Plants were treated with 0, 150, 300 and 450 mM NaCl at 20 days after sowing (DAS). Foliar application of Se (50 µM Na2SeO4) and B (1 mM H3BO3) was accomplished individually and in combined (Se+B) at three-day intervals, at 16, 20, 24 and 28 DAS under non-saline and saline conditions. Salt stress adversely affected the growth parameters. In salt-treated plants, proline content and oxidative stress indicators such as malondialdehyde (MDA) content and hydrogen peroxide (H2O2) content were increased with the increment of salt concentration but the relative water content decreased. Due to salt stress catalase (CAT), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), glyoxalase I (Gly I) and glyo...

Research paper thumbnail of Biostimulants for the Regulation of Reactive Oxygen Species Metabolism in Plants under Abiotic Stress

Cells

Global food security for a growing population with finite resources is often challenged by multip... more Global food security for a growing population with finite resources is often challenged by multiple, simultaneously occurring on-farm abiotic stresses (i.e., drought, salinity, low and high temperature, waterlogging, metal toxicity, etc.) due to climatic uncertainties and variability. Breeding for multiple stress tolerance is a long-term solution, though developing multiple-stress-tolerant crop varieties is still a challenge. Generation of reactive oxygen species in plant cells is a common response under diverse multiple abiotic stresses which play dual role of signaling molecules or damaging agents depending on concentration. Thus, a delicate balance of reactive oxygen species generation under stress may improve crop health, which depends on the natural antioxidant defense system of the plants. Biostimulants represent a promising type of environment-friendly formulation based on natural products that are frequently used exogenously to enhance abiotic stress tolerance. In this revie...

Research paper thumbnail of Nitric Oxide Regulates Plant Growth, Physiology, Antioxidant Defense, and Ion Homeostasis to Confer Salt Tolerance in the Mangrove Species, Kandelia obovata

Antioxidants

Facultative halophyte Kandelia obovata plants were exposed to mild (1.5% NaCl) and severe (3% NaC... more Facultative halophyte Kandelia obovata plants were exposed to mild (1.5% NaCl) and severe (3% NaCl) salt stress with or without sodium nitroprusside (SNP; 100 µM; a NO donor), hemoglobin (Hb, 100 µM; a NO scavenger), or Nω-nitro-L-arginine methyl ester (L-NAME, 100 µM; a NO synthase inhibitor). The plants were significantly affected by severe salt stress. They showed decreases in seedling growth, stomatal conductance, intercellular CO2 concentration, SPAD value, photosynthetic rate, transpiration rate, water use efficiency, and disrupted antioxidant defense systems, overproduction of reactive oxygen species, and visible oxidative damage. Salt stress also induced ion toxicity and disrupted nutrient homeostasis, as indicated by elevated leaf and root Na+ contents, decreased K+ contents, lower K+/Na+ ratios, and decreased Ca contents while increasing osmolyte (proline) levels. Treatment of salt-stressed plants with SNP increased endogenous NO levels, reduced ion toxicity, and improved ...

Research paper thumbnail of Regulation of Reactive Oxygen Species and Antioxidant Defense in Plants under Salinity

International Journal of Molecular Sciences

The generation of oxygen radicals and their derivatives, known as reactive oxygen species, (ROS) ... more The generation of oxygen radicals and their derivatives, known as reactive oxygen species, (ROS) is a part of the signaling process in higher plants at lower concentrations, but at higher concentrations, those ROS cause oxidative stress. Salinity-induced osmotic stress and ionic stress trigger the overproduction of ROS and, ultimately, result in oxidative damage to cell organelles and membrane components, and at severe levels, they cause cell and plant death. The antioxidant defense system protects the plant from salt-induced oxidative damage by detoxifying the ROS and also by maintaining the balance of ROS generation under salt stress. Different plant hormones and genes are also associated with the signaling and antioxidant defense system to protect plants when they are exposed to salt stress. Salt-induced ROS overgeneration is one of the major reasons for hampering the morpho-physiological and biochemical activities of plants which can be largely restored through enhancing the ant...

Research paper thumbnail of Selenium Toxicity in Plants and Environment: Biogeochemistry and Remediation Possibilities

Plants

Selenium (Se) is a widely distributed trace element with dual (beneficial or toxic) effects for h... more Selenium (Se) is a widely distributed trace element with dual (beneficial or toxic) effects for humans, animals, and plants. The availability of Se in the soil is reliant on the structure of the parental material and the procedures succeeding to soil formation. Anthropogenic activities affect the content of Se in the environment. Although plants are the core source of Se in animal and human diet, the role of Se in plants is still debatable. A low concentration of Se can be beneficial for plant growth, development, and ecophysiology both under optimum and unfavorable environmental conditions. However, excess Se results in toxic effects, especially in Se sensitive plants, due to changing structure and function of proteins and induce oxidative/nitrosative stress, which disrupts several metabolic processes. Contrary, Se hyperaccumulators absorb and tolerate exceedingly large amounts of Se, could be potentially used to remediate, i.e., remove, transfer, stabilize, and/or detoxify Se-cont...

Research paper thumbnail of Regulation of ROS Metabolism in Plants under Environmental Stress: A Review of Recent Experimental Evidence

International Journal of Molecular Sciences

Various environmental stresses singly or in combination generate excess amounts of reactive oxyge... more Various environmental stresses singly or in combination generate excess amounts of reactive oxygen species (ROS), leading to oxidative stress and impaired redox homeostasis. Generation of ROS is the obvious outcome of abiotic stresses and is gaining importance not only for their ubiquitous generation and subsequent damaging effects in plants but also for their diversified roles in signaling cascade, affecting other biomolecules, hormones concerning growth, development, or regulation of stress tolerance. Therefore, a good balance between ROS generation and the antioxidant defense system protects photosynthetic machinery, maintains membrane integrity, and prevents damage to nucleic acids and proteins. Notably, the antioxidant defense system not only scavenges ROS but also regulates the ROS titer for signaling. A glut of studies have been executed over the last few decades to discover the pattern of ROS generation and ROS scavenging. Reports suggested a sharp threshold level of ROS for...

Research paper thumbnail of β-Aminobutyric Acid Pretreatment Confers Salt Stress Tolerance in Brassica napus L. by Modulating Reactive Oxygen Species Metabolism and Methylglyoxal Detoxification

Plants

Salinity is a serious environmental hazard which limits world agricultural production by adversel... more Salinity is a serious environmental hazard which limits world agricultural production by adversely affecting plant physiology and biochemistry. Hence, increased tolerance against salt stress is very important. In this study, we explored the function of β-aminobutyric acid (BABA) in enhancing salt stress tolerance in rapeseed (Brassica napus L.). After pretreatment with BABA, seedlings were exposed to NaCl (100 and 150 mM) for 2 days. Salt stress increased Na content and decreased K content in shoot and root. It disrupted the antioxidant defense system by producing reactive oxygen species (ROS; H2O2 and O2•−), methylglyoxal (MG) content and causing oxidative stress. It also reduced the growth and photosynthetic pigments of seedlings but increased proline (Pro) content. However, BABA pretreatment in salt-stressed seedlings increased ascorbate (AsA) and glutathione (GSH) contents; GSH/GSSG ratio; and the activities of ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), ...

Research paper thumbnail of Regulation of Ascorbate-Glutathione Pathway in Mitigating Oxidative Damage in Plants under Abiotic Stress

Antioxidants

Reactive oxygen species (ROS) generation is a usual phenomenon in a plant both under a normal and... more Reactive oxygen species (ROS) generation is a usual phenomenon in a plant both under a normal and stressed condition. However, under unfavorable or adverse conditions, ROS production exceeds the capacity of the antioxidant defense system. Both non-enzymatic and enzymatic components of the antioxidant defense system either detoxify or scavenge ROS and mitigate their deleterious effects. The Ascorbate-Glutathione (AsA-GSH) pathway, also known as Asada–Halliwell pathway comprises of AsA, GSH, and four enzymes viz. ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase, play a vital role in detoxifying ROS. Apart from ROS detoxification, they also interact with other defense systems in plants and protect the plants from various abiotic stress-induced damages. Several plant studies revealed that the upregulation or overexpression of AsA-GSH pathway enzymes and the enhancement of the AsA and GSH levels conferred plants better tolerance ...

Research paper thumbnail of Phenological Variation and its Relation with Yield in several Wheat (Triticum aestivum L.) Cultivars under Normal and Late Sowing Mediated Heat Stress Condition

Notulae Scientia Biologicae

Phenological performance in relation to yield of five modern varieties of wheat Sourav, Pradip, S... more Phenological performance in relation to yield of five modern varieties of wheat Sourav, Pradip, Sufi, Shatabdi and Bijoy were evaluated under two growing environments; one is normal growing environment (sowing at November 30) and the other is post anthesis heat stressed environment (sowing at December 30). In case of late seeding, the varieties phased a significant level of high temperature stress that also significantly affected the required days to germination, booting, anthesis, maturity of all varieties including the yield as compared to normal sowing treatment. The temperature during the grain filling or grain maturing period was near 23C in case of normal seeding and it was near about 28C to 30C and sometimes reached above this range in the later period of late seeded treatment. In the normal sowing treatment the germination period was lower than the late sowing treatment as during that time the temperature was higher as compared to late sowing condition where temperature was ...

Research paper thumbnail of Exogenous nitric oxide donor and arginine provide protection against short-term drought stress in wheat seedlings

Physiology and Molecular Biology of Plants

Nitric oxide (NO) is an important plant signaling molecule that has a vital role in abiotic stres... more Nitric oxide (NO) is an important plant signaling molecule that has a vital role in abiotic stress tolerance. In the present study, we assessed drought-induced (15 and 30% PEG, polyethylene glycol) damage in wheat ( L. cv. Prodip) seedlings and mitigation by the synergistic effect of exogenous Arg (0.5 mM l-Arginine) and an NO donor (0.5 mM sodium nitroprusside, SNP). Drought stress sharply decreased the leaf relative water content (RWC) but markedly increased the proline (Pro) content in wheat seedlings. Drought stress caused overproduction of reactive oxygen species (ROS) and methylglyoxal (MG) due to the inefficiency of antioxidant enzymes, the glyoxalase system, and the ascorbate-glutathione pool. However, supplementation with the NO donor and Arg enhanced the antioxidant defense system (both non-enzymatic and enzymatic components) in drought-stressed seedlings. Application of the NO donor and Arg also enhanced the glyoxalase system and reduced the MG content by increasing the activities of the glyoxalase system enzymes (Gly I and Gly II), which restored the leaf RWC and further increased the Pro content under drought stress conditions. Exogenous NO donor and Arg application enhanced the endogenous NO content, which positively regulated the antioxidant system and reduced ROS production. Thus, the present study reveals the crucial roles of Arg and NO in enhancing drought stress tolerance in wheat seedlings by upgrading their water status and reducing oxidative stress and MG toxicity.

Research paper thumbnail of Insights into citric acid-induced cadmium tolerance and phytoremediation in Brassica juncea L.: Coordinated functions of metal chelation, antioxidant defense and glyoxalase systems

Ecotoxicology and environmental safety, 2018

Cadmium (Cd) is a serious environmental threat because it accumulates in plants from soil and is ... more Cadmium (Cd) is a serious environmental threat because it accumulates in plants from soil and is subsequently transported into the food cycle. Increased Cd uptake in plants disrupts plant metabolism and hampers crop growth and development. Therefore, remediation of Cd from soil and enhancing plant tolerance to metal toxicity is vital. In the present study, we investigated the function of different doses of citric acid (CA) on Cd toxicity in terms of metal accumulation and stress tolerance in mustard (Brassica juncea L.). Brassica juncea seedlings (12-day-old) were treated with Cd (0.5mMCd and 1.0mM CdCl) alone and in combination with CA (0.5mM and 1.0mM) in a semi-hydroponic medium for three days. Cadmium accumulation in the roots and shoots of the mustard seedlings increased in a dose-dependent manner and was higher in the roots. Increasing the Cd concentration led to reduced growth, biomass, water status, and chlorophyll (chl) content resulting from increased oxidative damage (ele...

Research paper thumbnail of Exogenous nitric oxide pretreatment protects Brassica napus L. seedlings from paraquat toxicity through the modulation of antioxidant defense and glyoxalase systems

Plant physiology and biochemistry : PPB, 2018

To investigate the physiological and biochemical mechanisms of nitric oxide (NO)-induced paraquat... more To investigate the physiological and biochemical mechanisms of nitric oxide (NO)-induced paraquat (PQ) tolerance in plants, we pretreated a set of 10-day-old Brassica napus seedlings with 500 μM sodium nitroprusside (SNP - a NO donor) for 24 h. Then, three doses of PQ (62.5, 125 and 250 μM) were applied separately, as well as to SNP-pretreated seedlings, and the seedlings were allowed to grow for an additional 48 h. The seedlings treated with PQ showed clear, dose-dependent signs of oxidative stress, with elevated levels of lipid peroxidation (MDA, malondialdehyde), HOand Ogeneration, and lipoxygenase (LOX) activity. Paraquat treatment disrupted pools of water-soluble antioxidants (ascorbate-AsA and reduced glutathione-GSH). Paraquat had different effects on the activities of antioxidant enzymes. The activities of glutathione reductase (GR) and catalase (CAT) decreased after PQ treatment in a dose-dependent manner, while the activities of ascorbate peroxidase (APX), dehydroascorbate...

Research paper thumbnail of Exogenous Silicon Attenuates Cadmium-Induced Oxidative Stress in Brassica napus L. by Modulating AsA-GSH Pathway and Glyoxalase System

Frontiers in plant science, 2017

Cadmium (Cd) brings a devastating health hazard to human being as a serious consequence of agricu... more Cadmium (Cd) brings a devastating health hazard to human being as a serious consequence of agricultural and environmental contamination. We demonstrated the protective effect of silicon (Si) on cadmium (Cd)-stressed rapeseed (Brassica napus L. cv. BINA Sharisha 3) plants through regulation of antioxidant defense and glyoxalase systems. Twelve-day-old seedlings were exposed to Cd stress (0.5 and 1.0 mM CdCl2) separately and in combination with Si (SiO2, 1.0 mM) for 2 days. Cadmium toxicity was evident by an obvious oxidative stress through sharp increases in H2O2 content and lipid peroxidation (malondialdehyde, MDA content), and visible sign of superoxide and H2O2. Cadmium stress also decreased the content of ascorbate (AsA) and glutathione (GSH) as well as their redox pool. The activities of monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR) and catalase (CAT) were decreased by Cd while ascorbate peroxidase (APX) and glutathione S-transferase (GST) activities ...

Research paper thumbnail of Roles of exogenous glutathione in antioxidant defense system and methylglyoxal detoxification during salt stress in mung bean

Biologia Plantarum

ABSTRACT The protective roles of glutathione (GSH) applied on salt stress-affected mung bean (Vig... more ABSTRACT The protective roles of glutathione (GSH) applied on salt stress-affected mung bean (Vigna radiata L.) seedlings were studied. Salt stress (200 mM NaCl) significantly increased the malondialdehyde (MDA), methylglyoxal (MG), H2O2, and proline (Pro) content, O2•− generation rate, and lipoxygenase (LOX) activity and reduced the leaf relative water content (RWC) and chlorophyll (Chl) content. The salt stress also significantly reduced the ascorbate (AsA) content, increased the endogenous GSH and glutathione disulfide (GSSG) content, and reduced the GSH/GSSG ratio. The activities of mono-dehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), and catalase (CAT) decreased; and the activities of ascorbate peroxidase (APX), glutathione reductase (GR), superoxide dismutase (SOD), glutathione S-transferase (GST), and glutathione peroxidase (GPX) increased under the salt stress. The activities of glyoxalase I (Gly I) and glyoxalase II (Gly II) decreased under the salt stress (except the Gly II activity at 48 h). Mung bean seedlings which were treated with NaCl together with GSH showed an improved AsA and GSH content, GSH/GSSG ratio, higher activities of APX (only at 24 h), MDHAR, DHAR, GR, SOD (only at 24 h), CAT, GPX (only at 48 h), GST (only at 24 h), Gly I and Gly II under the salt stress, compared with those treated with NaCl alone. The improved antioxidant and glyoxalase systems by GSH application decreased the MDA, H2O2, and MG content, O2•– generation rate, as well as increased the leaf RWC and Chl content. Thus, exogenous GSH improved the response of the mung bean seedlings to the salt stress.

Research paper thumbnail of Alleviation of osmotic stress in Brassica napus, B. campestris, and B. juncea by ascorbic acid application

Biologia Plantarum

The roles of ascorbic acid (AsA, 1 mM) under an osmotic stress [induced by 15 % (m/v) polyethylen... more The roles of ascorbic acid (AsA, 1 mM) under an osmotic stress [induced by 15 % (m/v) polyethylene glycol, PEG-6000] were investigated by examining morphological and physiological attributes in Brassica species. The osmotic stress reduced the fresh and dry masses, leaf relative water content (RWC), and chlorophyll (Chl) content, whereas increased the proline (Pro), malondialdehyde (MDA), and H 2 O 2 content, and lipoxygenase (LOX) activity. The ascorbate content in B. napus, B. campestris, and B. juncea decreased, increased, and remained unaltered, respectively. The dehydroascorbate (DHA) content increased only in B. napus. The AsA/DHA ratio was reduced by the osmotic stress in all the species except B. juncea. The osmotic stress increased the glutathione (GSH) content only in B. juncea, but increased the glutathione disulfide (GSSG) content and decreased the GSH/GSSG ratio in all the species. The osmotic stress increased the activities of ascorbate peroxidase (APX) (except in B. napus), glutathione reductase (GR) (except in B. napus), glutathione S-transferase (GST) (except in B. juncea), and glutathione peroxidase (GPX), and decreased the activities of catalase (CAT) and monodehydroascorbate reductase (MDHAR) (only in B. campestris). The osmotic stress decreased the glyoxalase I (Gly I) and increased glyoxalase II (Gly II) activities. The application of AsA in combination with PEG improved the fresh mass, RWC, and Chl content, whereas decreased the Pro, MDA, and H 2 O 2 content in comparison with PEG alone. The AsA addition improved AsA-GSH cycle components and improved the activities of all antioxidant and glyoxalase enzymes in most of the cases. So, exogenous AsA improved physiological adaptation and alleviated oxidative damage under the osmotic stress by improving the antioxidant and glyoxalase systems. According to measured parameters, B. juncea can be recognized as more drought tolerant than B. napus and B. campestris.

Research paper thumbnail of Maleic acid assisted improvement of metal chelation and antioxidant metabolism confers chromium tolerance in Brassica juncea L

Ecotoxicology and environmental safety, Jan 15, 2017

Chromium (Cr) is a highly toxic environmental pollutant that negatively affects plant growth and ... more Chromium (Cr) is a highly toxic environmental pollutant that negatively affects plant growth and development. Thus, remediating Cr from soil or increasing plant tolerance against Cr stress is urgent. Organic acids are recognized as agents of phytoremediation and as exogenous protectants, but using maleic acid (MA) to attain these results has not yet been studied. Therefore, our study investigated the effects of MA on Cr uptake and mitigation of Cr toxicity. We treated 8-d-old Indian mustard (Brassica juncea L.) seedlings with Cr (0.15mM and 0.3mM K2CrO4, 5 days) alone and in combination with MA (0.25mM) in a semi-hydroponic medium. Under Cr stress, plants accumulated Cr in both the roots and shoots in a dose-dependent manner, where the roots showed higher accumulation. Chromium stress reduced the growth and biomass of the Indian mustard plants by reducing water status and photosynthetic pigments, and increased oxidative damage due to generation of toxic reactive oxygen species (ROS)...

Research paper thumbnail of γ-aminobutyric acid (GABA) confers chromium stress tolerance in Brassica juncea L. by modulating the antioxidant defense and glyoxalase systems

Ecotoxicology (London, England), Jan 13, 2017

Chromium (Cr) toxicity is hazardous to the seed germination, growth, and development of plants. γ... more Chromium (Cr) toxicity is hazardous to the seed germination, growth, and development of plants. γ-aminobutyric acid (GABA) is a non-protein amino acid and is involved in stress tolerance in plants. To investigate the effects of GABA in alleviating Cr toxicity, we treated eight-d-old mustard (Brassica juncea L.) seedlings with Cr (0.15 and 0.3 mM K2CrO4, 5 days) alone and in combination with GABA (125 µM) in a semi-hydroponic medium. The roots and shoots of the seedlings accumulated Cr in a dose-dependent manner, which led to an increase in oxidative damage [lipid peroxidation; hydrogen peroxide (H2O2) content; superoxide (O2(•-)) generation; lipoxygenase (LOX) activity], methylglyoxal (MG) content, and disrupted antioxidant defense and glyoxalase systems. Chromium stress also reduced growth, leaf relative water content (RWC), and chlorophyll (chl) content but increased phytochelatin (PC) and proline (Pro) content. Furthermore, supplementing the Cr-treated seedlings with GABA reduced...

Research paper thumbnail of Glutathione in plants: biosynthesis and physiological role in environmental stress tolerance

Physiology and Molecular Biology of Plants, 2017

Glutathione (GSH; γ-glutamyl-cysteinyl-glycine) is a small intracellular thiol molecule which is ... more Glutathione (GSH; γ-glutamyl-cysteinyl-glycine) is a small intracellular thiol molecule which is considered as a strong non-enzymatic antioxidant. Glutathione regulates multiple metabolic functions; for example, it protects membranes by maintaining the reduced state of both α-tocopherol and zeaxanthin, it prevents the oxidative denaturation of proteins under stress conditions by protecting their thiol groups, and it serves as a substrate for both glutathione peroxidase and glutathione S-transferase. By acting as a precursor of phytochelatins, GSH helps in the chelating of toxic metals/metalloids which are then transported and sequestered in the vacuole. The glyoxalase pathway (consisting of glyoxalase I and glyoxalase II enzymes) for detoxification of methylglyoxal, a cytotoxic molecule, also requires GSH in the first reaction step. For these reasons, much attention has recently been directed to elucidation of the role of this molecule in conferring tolerance to abiotic stress. Recently, this molecule has drawn much attention because of its interaction with other signaling molecules and phytohormones. In this review, we have discussed the recent progress in GSH biosynthesis, metabolism and its role in abiotic stress tolerance.

Research paper thumbnail of Salt Stress Tolerance in Rice: Emerging Role of Exogenous Phytoprotectants

Advances in International Rice Research, 2017

Excess salinity in soil is one of the major environmental factors that limit plant growth and yie... more Excess salinity in soil is one of the major environmental factors that limit plant growth and yield of a wide variety of crops including rice. On the basis of tolerance ability toward salinity, rice is considered as salt-sensitive crop, and growth and yield of rice are greatly affected by salinity. In general, rice can tolerate a small amount of saltwater without compromising the growth and yield. However, it greatly depends on the types and species of rice and their growth stage. Salinity-induced ionic and osmotic stresses reduce rate of photosynthesis and consequently cause oxidative stress, which is also responsible for growth reduction. The negative effects of salt stress that mentioned ultimately reduced yield of most crops including rice, except some halophytes. In recent decades, researchers have developed various approaches toward making salt-tolerant rice varieties. Using phytoprotectants is found to be effective in conferring salt tolerance to rice plants. In this chapter, we reviewed the recent reports on different aspects on salt stress tolerance strategies in light of using phytoprotectants.

Research paper thumbnail of Hydrogen Peroxide Pretreatment Mitigates Cadmium-Induced Oxidative Stress in Brassica napus L.: An Intrinsic Study on Antioxidant Defense and Glyoxalase Systems

Frontiers in plant science, 2017

Cadmium (Cd) is considered as one of the most toxic metals for plant growth and development. In t... more Cadmium (Cd) is considered as one of the most toxic metals for plant growth and development. In the present study, we investigated the role of externally applied hydrogen peroxide (H2O2) in regulating the antioxidant defense and glyoxalase systems in conferring Cd-induced oxidative stress tolerance in rapeseed (Brassica napus L.). Seedlings were pretreated with 50 μM H2O2 for 24 h. These pretreated seedlings as well as non-pretreated seedlings were grown for another 48 h at two concentrations of CdCl(2) (0.5 and 1.0 mM). Both the levels of Cd increased MDA and H2O2 levels and lipoxygenase activity while ascorbate (AsA) declined significantly. However, reduced glutathione (GSH) content showed an increase at 0.5 mM CdCl(2), but glutathione disulfide (GSSG) increased at any level of Cd with a decrease in GSH/GSSG ratio. The activities of ascorbate peroxidase (APX) and glutathione S-transferase (GST) upregulated due to Cd treatment in dose-dependent manners, while glutathione reductase ...

Research paper thumbnail of Supplemental Selenium and Boron Mitigate Salt-Induced Oxidative Damages in Glycine max L

Plants

The present investigation was executed with an aim to evaluate the role of exogenous selenium (Se... more The present investigation was executed with an aim to evaluate the role of exogenous selenium (Se) and boron (B) in mitigating different levels of salt stress by enhancing the reactive oxygen species (ROS) scavenging, antioxidant defense and glyoxalase systems in soybean. Plants were treated with 0, 150, 300 and 450 mM NaCl at 20 days after sowing (DAS). Foliar application of Se (50 µM Na2SeO4) and B (1 mM H3BO3) was accomplished individually and in combined (Se+B) at three-day intervals, at 16, 20, 24 and 28 DAS under non-saline and saline conditions. Salt stress adversely affected the growth parameters. In salt-treated plants, proline content and oxidative stress indicators such as malondialdehyde (MDA) content and hydrogen peroxide (H2O2) content were increased with the increment of salt concentration but the relative water content decreased. Due to salt stress catalase (CAT), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), glyoxalase I (Gly I) and glyo...

Research paper thumbnail of Biostimulants for the Regulation of Reactive Oxygen Species Metabolism in Plants under Abiotic Stress

Cells

Global food security for a growing population with finite resources is often challenged by multip... more Global food security for a growing population with finite resources is often challenged by multiple, simultaneously occurring on-farm abiotic stresses (i.e., drought, salinity, low and high temperature, waterlogging, metal toxicity, etc.) due to climatic uncertainties and variability. Breeding for multiple stress tolerance is a long-term solution, though developing multiple-stress-tolerant crop varieties is still a challenge. Generation of reactive oxygen species in plant cells is a common response under diverse multiple abiotic stresses which play dual role of signaling molecules or damaging agents depending on concentration. Thus, a delicate balance of reactive oxygen species generation under stress may improve crop health, which depends on the natural antioxidant defense system of the plants. Biostimulants represent a promising type of environment-friendly formulation based on natural products that are frequently used exogenously to enhance abiotic stress tolerance. In this revie...

Research paper thumbnail of Nitric Oxide Regulates Plant Growth, Physiology, Antioxidant Defense, and Ion Homeostasis to Confer Salt Tolerance in the Mangrove Species, Kandelia obovata

Antioxidants

Facultative halophyte Kandelia obovata plants were exposed to mild (1.5% NaCl) and severe (3% NaC... more Facultative halophyte Kandelia obovata plants were exposed to mild (1.5% NaCl) and severe (3% NaCl) salt stress with or without sodium nitroprusside (SNP; 100 µM; a NO donor), hemoglobin (Hb, 100 µM; a NO scavenger), or Nω-nitro-L-arginine methyl ester (L-NAME, 100 µM; a NO synthase inhibitor). The plants were significantly affected by severe salt stress. They showed decreases in seedling growth, stomatal conductance, intercellular CO2 concentration, SPAD value, photosynthetic rate, transpiration rate, water use efficiency, and disrupted antioxidant defense systems, overproduction of reactive oxygen species, and visible oxidative damage. Salt stress also induced ion toxicity and disrupted nutrient homeostasis, as indicated by elevated leaf and root Na+ contents, decreased K+ contents, lower K+/Na+ ratios, and decreased Ca contents while increasing osmolyte (proline) levels. Treatment of salt-stressed plants with SNP increased endogenous NO levels, reduced ion toxicity, and improved ...

Research paper thumbnail of Regulation of Reactive Oxygen Species and Antioxidant Defense in Plants under Salinity

International Journal of Molecular Sciences

The generation of oxygen radicals and their derivatives, known as reactive oxygen species, (ROS) ... more The generation of oxygen radicals and their derivatives, known as reactive oxygen species, (ROS) is a part of the signaling process in higher plants at lower concentrations, but at higher concentrations, those ROS cause oxidative stress. Salinity-induced osmotic stress and ionic stress trigger the overproduction of ROS and, ultimately, result in oxidative damage to cell organelles and membrane components, and at severe levels, they cause cell and plant death. The antioxidant defense system protects the plant from salt-induced oxidative damage by detoxifying the ROS and also by maintaining the balance of ROS generation under salt stress. Different plant hormones and genes are also associated with the signaling and antioxidant defense system to protect plants when they are exposed to salt stress. Salt-induced ROS overgeneration is one of the major reasons for hampering the morpho-physiological and biochemical activities of plants which can be largely restored through enhancing the ant...

Research paper thumbnail of Selenium Toxicity in Plants and Environment: Biogeochemistry and Remediation Possibilities

Plants

Selenium (Se) is a widely distributed trace element with dual (beneficial or toxic) effects for h... more Selenium (Se) is a widely distributed trace element with dual (beneficial or toxic) effects for humans, animals, and plants. The availability of Se in the soil is reliant on the structure of the parental material and the procedures succeeding to soil formation. Anthropogenic activities affect the content of Se in the environment. Although plants are the core source of Se in animal and human diet, the role of Se in plants is still debatable. A low concentration of Se can be beneficial for plant growth, development, and ecophysiology both under optimum and unfavorable environmental conditions. However, excess Se results in toxic effects, especially in Se sensitive plants, due to changing structure and function of proteins and induce oxidative/nitrosative stress, which disrupts several metabolic processes. Contrary, Se hyperaccumulators absorb and tolerate exceedingly large amounts of Se, could be potentially used to remediate, i.e., remove, transfer, stabilize, and/or detoxify Se-cont...

Research paper thumbnail of Regulation of ROS Metabolism in Plants under Environmental Stress: A Review of Recent Experimental Evidence

International Journal of Molecular Sciences

Various environmental stresses singly or in combination generate excess amounts of reactive oxyge... more Various environmental stresses singly or in combination generate excess amounts of reactive oxygen species (ROS), leading to oxidative stress and impaired redox homeostasis. Generation of ROS is the obvious outcome of abiotic stresses and is gaining importance not only for their ubiquitous generation and subsequent damaging effects in plants but also for their diversified roles in signaling cascade, affecting other biomolecules, hormones concerning growth, development, or regulation of stress tolerance. Therefore, a good balance between ROS generation and the antioxidant defense system protects photosynthetic machinery, maintains membrane integrity, and prevents damage to nucleic acids and proteins. Notably, the antioxidant defense system not only scavenges ROS but also regulates the ROS titer for signaling. A glut of studies have been executed over the last few decades to discover the pattern of ROS generation and ROS scavenging. Reports suggested a sharp threshold level of ROS for...

Research paper thumbnail of β-Aminobutyric Acid Pretreatment Confers Salt Stress Tolerance in Brassica napus L. by Modulating Reactive Oxygen Species Metabolism and Methylglyoxal Detoxification

Plants

Salinity is a serious environmental hazard which limits world agricultural production by adversel... more Salinity is a serious environmental hazard which limits world agricultural production by adversely affecting plant physiology and biochemistry. Hence, increased tolerance against salt stress is very important. In this study, we explored the function of β-aminobutyric acid (BABA) in enhancing salt stress tolerance in rapeseed (Brassica napus L.). After pretreatment with BABA, seedlings were exposed to NaCl (100 and 150 mM) for 2 days. Salt stress increased Na content and decreased K content in shoot and root. It disrupted the antioxidant defense system by producing reactive oxygen species (ROS; H2O2 and O2•−), methylglyoxal (MG) content and causing oxidative stress. It also reduced the growth and photosynthetic pigments of seedlings but increased proline (Pro) content. However, BABA pretreatment in salt-stressed seedlings increased ascorbate (AsA) and glutathione (GSH) contents; GSH/GSSG ratio; and the activities of ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), ...

Research paper thumbnail of Regulation of Ascorbate-Glutathione Pathway in Mitigating Oxidative Damage in Plants under Abiotic Stress

Antioxidants

Reactive oxygen species (ROS) generation is a usual phenomenon in a plant both under a normal and... more Reactive oxygen species (ROS) generation is a usual phenomenon in a plant both under a normal and stressed condition. However, under unfavorable or adverse conditions, ROS production exceeds the capacity of the antioxidant defense system. Both non-enzymatic and enzymatic components of the antioxidant defense system either detoxify or scavenge ROS and mitigate their deleterious effects. The Ascorbate-Glutathione (AsA-GSH) pathway, also known as Asada–Halliwell pathway comprises of AsA, GSH, and four enzymes viz. ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase, play a vital role in detoxifying ROS. Apart from ROS detoxification, they also interact with other defense systems in plants and protect the plants from various abiotic stress-induced damages. Several plant studies revealed that the upregulation or overexpression of AsA-GSH pathway enzymes and the enhancement of the AsA and GSH levels conferred plants better tolerance ...

Research paper thumbnail of Phenological Variation and its Relation with Yield in several Wheat (Triticum aestivum L.) Cultivars under Normal and Late Sowing Mediated Heat Stress Condition

Notulae Scientia Biologicae

Phenological performance in relation to yield of five modern varieties of wheat Sourav, Pradip, S... more Phenological performance in relation to yield of five modern varieties of wheat Sourav, Pradip, Sufi, Shatabdi and Bijoy were evaluated under two growing environments; one is normal growing environment (sowing at November 30) and the other is post anthesis heat stressed environment (sowing at December 30). In case of late seeding, the varieties phased a significant level of high temperature stress that also significantly affected the required days to germination, booting, anthesis, maturity of all varieties including the yield as compared to normal sowing treatment. The temperature during the grain filling or grain maturing period was near 23C in case of normal seeding and it was near about 28C to 30C and sometimes reached above this range in the later period of late seeded treatment. In the normal sowing treatment the germination period was lower than the late sowing treatment as during that time the temperature was higher as compared to late sowing condition where temperature was ...

Research paper thumbnail of Exogenous nitric oxide donor and arginine provide protection against short-term drought stress in wheat seedlings

Physiology and Molecular Biology of Plants

Nitric oxide (NO) is an important plant signaling molecule that has a vital role in abiotic stres... more Nitric oxide (NO) is an important plant signaling molecule that has a vital role in abiotic stress tolerance. In the present study, we assessed drought-induced (15 and 30% PEG, polyethylene glycol) damage in wheat ( L. cv. Prodip) seedlings and mitigation by the synergistic effect of exogenous Arg (0.5 mM l-Arginine) and an NO donor (0.5 mM sodium nitroprusside, SNP). Drought stress sharply decreased the leaf relative water content (RWC) but markedly increased the proline (Pro) content in wheat seedlings. Drought stress caused overproduction of reactive oxygen species (ROS) and methylglyoxal (MG) due to the inefficiency of antioxidant enzymes, the glyoxalase system, and the ascorbate-glutathione pool. However, supplementation with the NO donor and Arg enhanced the antioxidant defense system (both non-enzymatic and enzymatic components) in drought-stressed seedlings. Application of the NO donor and Arg also enhanced the glyoxalase system and reduced the MG content by increasing the activities of the glyoxalase system enzymes (Gly I and Gly II), which restored the leaf RWC and further increased the Pro content under drought stress conditions. Exogenous NO donor and Arg application enhanced the endogenous NO content, which positively regulated the antioxidant system and reduced ROS production. Thus, the present study reveals the crucial roles of Arg and NO in enhancing drought stress tolerance in wheat seedlings by upgrading their water status and reducing oxidative stress and MG toxicity.

Research paper thumbnail of Insights into citric acid-induced cadmium tolerance and phytoremediation in Brassica juncea L.: Coordinated functions of metal chelation, antioxidant defense and glyoxalase systems

Ecotoxicology and environmental safety, 2018

Cadmium (Cd) is a serious environmental threat because it accumulates in plants from soil and is ... more Cadmium (Cd) is a serious environmental threat because it accumulates in plants from soil and is subsequently transported into the food cycle. Increased Cd uptake in plants disrupts plant metabolism and hampers crop growth and development. Therefore, remediation of Cd from soil and enhancing plant tolerance to metal toxicity is vital. In the present study, we investigated the function of different doses of citric acid (CA) on Cd toxicity in terms of metal accumulation and stress tolerance in mustard (Brassica juncea L.). Brassica juncea seedlings (12-day-old) were treated with Cd (0.5mMCd and 1.0mM CdCl) alone and in combination with CA (0.5mM and 1.0mM) in a semi-hydroponic medium for three days. Cadmium accumulation in the roots and shoots of the mustard seedlings increased in a dose-dependent manner and was higher in the roots. Increasing the Cd concentration led to reduced growth, biomass, water status, and chlorophyll (chl) content resulting from increased oxidative damage (ele...

Research paper thumbnail of Exogenous nitric oxide pretreatment protects Brassica napus L. seedlings from paraquat toxicity through the modulation of antioxidant defense and glyoxalase systems

Plant physiology and biochemistry : PPB, 2018

To investigate the physiological and biochemical mechanisms of nitric oxide (NO)-induced paraquat... more To investigate the physiological and biochemical mechanisms of nitric oxide (NO)-induced paraquat (PQ) tolerance in plants, we pretreated a set of 10-day-old Brassica napus seedlings with 500 μM sodium nitroprusside (SNP - a NO donor) for 24 h. Then, three doses of PQ (62.5, 125 and 250 μM) were applied separately, as well as to SNP-pretreated seedlings, and the seedlings were allowed to grow for an additional 48 h. The seedlings treated with PQ showed clear, dose-dependent signs of oxidative stress, with elevated levels of lipid peroxidation (MDA, malondialdehyde), HOand Ogeneration, and lipoxygenase (LOX) activity. Paraquat treatment disrupted pools of water-soluble antioxidants (ascorbate-AsA and reduced glutathione-GSH). Paraquat had different effects on the activities of antioxidant enzymes. The activities of glutathione reductase (GR) and catalase (CAT) decreased after PQ treatment in a dose-dependent manner, while the activities of ascorbate peroxidase (APX), dehydroascorbate...

Research paper thumbnail of Exogenous Silicon Attenuates Cadmium-Induced Oxidative Stress in Brassica napus L. by Modulating AsA-GSH Pathway and Glyoxalase System

Frontiers in plant science, 2017

Cadmium (Cd) brings a devastating health hazard to human being as a serious consequence of agricu... more Cadmium (Cd) brings a devastating health hazard to human being as a serious consequence of agricultural and environmental contamination. We demonstrated the protective effect of silicon (Si) on cadmium (Cd)-stressed rapeseed (Brassica napus L. cv. BINA Sharisha 3) plants through regulation of antioxidant defense and glyoxalase systems. Twelve-day-old seedlings were exposed to Cd stress (0.5 and 1.0 mM CdCl2) separately and in combination with Si (SiO2, 1.0 mM) for 2 days. Cadmium toxicity was evident by an obvious oxidative stress through sharp increases in H2O2 content and lipid peroxidation (malondialdehyde, MDA content), and visible sign of superoxide and H2O2. Cadmium stress also decreased the content of ascorbate (AsA) and glutathione (GSH) as well as their redox pool. The activities of monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR) and catalase (CAT) were decreased by Cd while ascorbate peroxidase (APX) and glutathione S-transferase (GST) activities ...

Research paper thumbnail of Roles of exogenous glutathione in antioxidant defense system and methylglyoxal detoxification during salt stress in mung bean

Biologia Plantarum

ABSTRACT The protective roles of glutathione (GSH) applied on salt stress-affected mung bean (Vig... more ABSTRACT The protective roles of glutathione (GSH) applied on salt stress-affected mung bean (Vigna radiata L.) seedlings were studied. Salt stress (200 mM NaCl) significantly increased the malondialdehyde (MDA), methylglyoxal (MG), H2O2, and proline (Pro) content, O2•− generation rate, and lipoxygenase (LOX) activity and reduced the leaf relative water content (RWC) and chlorophyll (Chl) content. The salt stress also significantly reduced the ascorbate (AsA) content, increased the endogenous GSH and glutathione disulfide (GSSG) content, and reduced the GSH/GSSG ratio. The activities of mono-dehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), and catalase (CAT) decreased; and the activities of ascorbate peroxidase (APX), glutathione reductase (GR), superoxide dismutase (SOD), glutathione S-transferase (GST), and glutathione peroxidase (GPX) increased under the salt stress. The activities of glyoxalase I (Gly I) and glyoxalase II (Gly II) decreased under the salt stress (except the Gly II activity at 48 h). Mung bean seedlings which were treated with NaCl together with GSH showed an improved AsA and GSH content, GSH/GSSG ratio, higher activities of APX (only at 24 h), MDHAR, DHAR, GR, SOD (only at 24 h), CAT, GPX (only at 48 h), GST (only at 24 h), Gly I and Gly II under the salt stress, compared with those treated with NaCl alone. The improved antioxidant and glyoxalase systems by GSH application decreased the MDA, H2O2, and MG content, O2•– generation rate, as well as increased the leaf RWC and Chl content. Thus, exogenous GSH improved the response of the mung bean seedlings to the salt stress.

Research paper thumbnail of Alleviation of osmotic stress in Brassica napus, B. campestris, and B. juncea by ascorbic acid application

Biologia Plantarum

The roles of ascorbic acid (AsA, 1 mM) under an osmotic stress [induced by 15 % (m/v) polyethylen... more The roles of ascorbic acid (AsA, 1 mM) under an osmotic stress [induced by 15 % (m/v) polyethylene glycol, PEG-6000] were investigated by examining morphological and physiological attributes in Brassica species. The osmotic stress reduced the fresh and dry masses, leaf relative water content (RWC), and chlorophyll (Chl) content, whereas increased the proline (Pro), malondialdehyde (MDA), and H 2 O 2 content, and lipoxygenase (LOX) activity. The ascorbate content in B. napus, B. campestris, and B. juncea decreased, increased, and remained unaltered, respectively. The dehydroascorbate (DHA) content increased only in B. napus. The AsA/DHA ratio was reduced by the osmotic stress in all the species except B. juncea. The osmotic stress increased the glutathione (GSH) content only in B. juncea, but increased the glutathione disulfide (GSSG) content and decreased the GSH/GSSG ratio in all the species. The osmotic stress increased the activities of ascorbate peroxidase (APX) (except in B. napus), glutathione reductase (GR) (except in B. napus), glutathione S-transferase (GST) (except in B. juncea), and glutathione peroxidase (GPX), and decreased the activities of catalase (CAT) and monodehydroascorbate reductase (MDHAR) (only in B. campestris). The osmotic stress decreased the glyoxalase I (Gly I) and increased glyoxalase II (Gly II) activities. The application of AsA in combination with PEG improved the fresh mass, RWC, and Chl content, whereas decreased the Pro, MDA, and H 2 O 2 content in comparison with PEG alone. The AsA addition improved AsA-GSH cycle components and improved the activities of all antioxidant and glyoxalase enzymes in most of the cases. So, exogenous AsA improved physiological adaptation and alleviated oxidative damage under the osmotic stress by improving the antioxidant and glyoxalase systems. According to measured parameters, B. juncea can be recognized as more drought tolerant than B. napus and B. campestris.

Research paper thumbnail of Maleic acid assisted improvement of metal chelation and antioxidant metabolism confers chromium tolerance in Brassica juncea L

Ecotoxicology and environmental safety, Jan 15, 2017

Chromium (Cr) is a highly toxic environmental pollutant that negatively affects plant growth and ... more Chromium (Cr) is a highly toxic environmental pollutant that negatively affects plant growth and development. Thus, remediating Cr from soil or increasing plant tolerance against Cr stress is urgent. Organic acids are recognized as agents of phytoremediation and as exogenous protectants, but using maleic acid (MA) to attain these results has not yet been studied. Therefore, our study investigated the effects of MA on Cr uptake and mitigation of Cr toxicity. We treated 8-d-old Indian mustard (Brassica juncea L.) seedlings with Cr (0.15mM and 0.3mM K2CrO4, 5 days) alone and in combination with MA (0.25mM) in a semi-hydroponic medium. Under Cr stress, plants accumulated Cr in both the roots and shoots in a dose-dependent manner, where the roots showed higher accumulation. Chromium stress reduced the growth and biomass of the Indian mustard plants by reducing water status and photosynthetic pigments, and increased oxidative damage due to generation of toxic reactive oxygen species (ROS)...

Research paper thumbnail of γ-aminobutyric acid (GABA) confers chromium stress tolerance in Brassica juncea L. by modulating the antioxidant defense and glyoxalase systems

Ecotoxicology (London, England), Jan 13, 2017

Chromium (Cr) toxicity is hazardous to the seed germination, growth, and development of plants. γ... more Chromium (Cr) toxicity is hazardous to the seed germination, growth, and development of plants. γ-aminobutyric acid (GABA) is a non-protein amino acid and is involved in stress tolerance in plants. To investigate the effects of GABA in alleviating Cr toxicity, we treated eight-d-old mustard (Brassica juncea L.) seedlings with Cr (0.15 and 0.3 mM K2CrO4, 5 days) alone and in combination with GABA (125 µM) in a semi-hydroponic medium. The roots and shoots of the seedlings accumulated Cr in a dose-dependent manner, which led to an increase in oxidative damage [lipid peroxidation; hydrogen peroxide (H2O2) content; superoxide (O2(•-)) generation; lipoxygenase (LOX) activity], methylglyoxal (MG) content, and disrupted antioxidant defense and glyoxalase systems. Chromium stress also reduced growth, leaf relative water content (RWC), and chlorophyll (chl) content but increased phytochelatin (PC) and proline (Pro) content. Furthermore, supplementing the Cr-treated seedlings with GABA reduced...

Research paper thumbnail of Glutathione in plants: biosynthesis and physiological role in environmental stress tolerance

Physiology and Molecular Biology of Plants, 2017

Glutathione (GSH; γ-glutamyl-cysteinyl-glycine) is a small intracellular thiol molecule which is ... more Glutathione (GSH; γ-glutamyl-cysteinyl-glycine) is a small intracellular thiol molecule which is considered as a strong non-enzymatic antioxidant. Glutathione regulates multiple metabolic functions; for example, it protects membranes by maintaining the reduced state of both α-tocopherol and zeaxanthin, it prevents the oxidative denaturation of proteins under stress conditions by protecting their thiol groups, and it serves as a substrate for both glutathione peroxidase and glutathione S-transferase. By acting as a precursor of phytochelatins, GSH helps in the chelating of toxic metals/metalloids which are then transported and sequestered in the vacuole. The glyoxalase pathway (consisting of glyoxalase I and glyoxalase II enzymes) for detoxification of methylglyoxal, a cytotoxic molecule, also requires GSH in the first reaction step. For these reasons, much attention has recently been directed to elucidation of the role of this molecule in conferring tolerance to abiotic stress. Recently, this molecule has drawn much attention because of its interaction with other signaling molecules and phytohormones. In this review, we have discussed the recent progress in GSH biosynthesis, metabolism and its role in abiotic stress tolerance.

Research paper thumbnail of Salt Stress Tolerance in Rice: Emerging Role of Exogenous Phytoprotectants

Advances in International Rice Research, 2017

Excess salinity in soil is one of the major environmental factors that limit plant growth and yie... more Excess salinity in soil is one of the major environmental factors that limit plant growth and yield of a wide variety of crops including rice. On the basis of tolerance ability toward salinity, rice is considered as salt-sensitive crop, and growth and yield of rice are greatly affected by salinity. In general, rice can tolerate a small amount of saltwater without compromising the growth and yield. However, it greatly depends on the types and species of rice and their growth stage. Salinity-induced ionic and osmotic stresses reduce rate of photosynthesis and consequently cause oxidative stress, which is also responsible for growth reduction. The negative effects of salt stress that mentioned ultimately reduced yield of most crops including rice, except some halophytes. In recent decades, researchers have developed various approaches toward making salt-tolerant rice varieties. Using phytoprotectants is found to be effective in conferring salt tolerance to rice plants. In this chapter, we reviewed the recent reports on different aspects on salt stress tolerance strategies in light of using phytoprotectants.

Research paper thumbnail of Hydrogen Peroxide Pretreatment Mitigates Cadmium-Induced Oxidative Stress in Brassica napus L.: An Intrinsic Study on Antioxidant Defense and Glyoxalase Systems

Frontiers in plant science, 2017

Cadmium (Cd) is considered as one of the most toxic metals for plant growth and development. In t... more Cadmium (Cd) is considered as one of the most toxic metals for plant growth and development. In the present study, we investigated the role of externally applied hydrogen peroxide (H2O2) in regulating the antioxidant defense and glyoxalase systems in conferring Cd-induced oxidative stress tolerance in rapeseed (Brassica napus L.). Seedlings were pretreated with 50 μM H2O2 for 24 h. These pretreated seedlings as well as non-pretreated seedlings were grown for another 48 h at two concentrations of CdCl(2) (0.5 and 1.0 mM). Both the levels of Cd increased MDA and H2O2 levels and lipoxygenase activity while ascorbate (AsA) declined significantly. However, reduced glutathione (GSH) content showed an increase at 0.5 mM CdCl(2), but glutathione disulfide (GSSG) increased at any level of Cd with a decrease in GSH/GSSG ratio. The activities of ascorbate peroxidase (APX) and glutathione S-transferase (GST) upregulated due to Cd treatment in dose-dependent manners, while glutathione reductase ...