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1.
Plant Physiol Biochem ; 160: 386-396, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33556754

RESUMO

Reactive oxygen species (ROS) such as hydrogen peroxide at low concentrations act as signaling of several abiotic stresses. Overproduction of hydrogen peroxide causes the oxidation of plant cell lipid phosphate layer promoting senescence and cell death. To mitigate the effect of ROS, plants develop antioxidant defense mechanisms (superoxide dismutase, catalase, guaiacol peroxidase), ascorbate-glutathione cycle enzymes (ASA-GSH) (ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase and glutathione reductase), which have the function of removing and transforming ROS into non-toxic substances to maintain cellular homeostasis. Foliar or soil application of fertilizers containing B, Cu, Fe, Mn, Mo, Ni, Se and Zn at low concentrations has the ability to elicit and activate antioxidative enzymes, non-oxidizing metabolism, as well as sugar metabolism to mitigate damage by oxidative stress. Plants treated with micronutrients show higher tolerance to abiotic stress and better nutritional status. In this review, we summarized results indicating micronutrient actions in order to reduce ROS resulting the increase of photosynthetic capacity of plants for greater crop yield. This meta-analysis provides information on the mechanism of action of micronutrients in combating ROS, which can make plants more tolerant to several types of abiotic stress such as extreme temperatures, salinity, heavy metals and excess light.


Assuntos
Fertilizantes , Micronutrientes , Plantas , Espécies Reativas de Oxigênio/metabolismo , Estresse Fisiológico , Antioxidantes/metabolismo , Ascorbato Peroxidases/metabolismo , Glutationa/metabolismo , Estresse Oxidativo , Superóxido Dismutase/metabolismo
2.
J Plant Res ; 134(2): 237-248, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33591473

RESUMO

Flooding stress nowadays is one of the major stressors for plants under climate change. This kind of stress may cause severe depression of the plant's growth through inhibition of photosynthesis and oxidative cell damage as well as changes in cell respiration. The present work aimed to study the effect of flooding stress on oxidative and antioxidative parameters in leaves of two maize hybrids (ZP 555 and ZP 606). Leaves of maize plants at the stage of three fully developed leaves were harvested after 6, 24, 72, and 144 h of applied flooding stress. Leaves were used for determination of physiological (the content of photosynthetic pigments and soluble proteins), oxidative stress parameters (the content of malondialdehyde (MDA) and H2O2) as well as antioxidants (the total polyphenols content, and activity of antioxidative enzymes [catalase (CAT, EC 1.11.1.6), superoxide dismutase (SOD, EC 1.15.1.1), and Class III peroxidases (POX, EC, 1.11.1.7)]). Results indicated that flooding stress-induced time-dependent changes of measured parameters and those hybrids differ in response to stress. The noticeable difference between hybrids was detected in the H2O2 and MDA content. An increase in the activity of SOD, POX and polyphenols content, with the most pronounced changes in POX activity and polyphenols concentration, could minimize the cellular damage caused by flooding. The results of the present study suggest that a more robust antioxidative metabolism is essential under flooding stress and could be a protective strategy against oxidative damage induced by flooding in ZP 606 maize plants compared to ZP 555 plants.


Assuntos
Antioxidantes , Zea mays , Ascorbato Peroxidases/metabolismo , Catalase/metabolismo , Peróxido de Hidrogênio , Peroxidação de Lipídeos , Estresse Oxidativo , Folhas de Planta/metabolismo , Superóxido Dismutase/metabolismo , Zea mays/metabolismo
3.
Ecotoxicol Environ Saf ; 210: 111906, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33429318

RESUMO

In the present work, the effect of seed pre-soaking with gallic acid (GA; 3,4,5-triphydroxyl-benzoic acid) in conferring subsequent tolerance to Cd stress in sunflower (Helianthus annuus) seedlings was investigated. Exposing sunflower seedlings to increasing Cd concentrations (5, 10 and 20 µM) caused a gradual decrease in root and shoot biomass and increased the metal accumulation in both organs. Seed pretreatment with 75 µM GA significantly restricted Cd uptake, markedly alleviated Cd-induced plant growth inhibition, and mitigated the oxidative damages caused by this metal, as compared to plants directly exposed to Cd. GA pre-soaking prior to Cd stress also enhanced catalase, ascorbate peroxidase and glutathione reductase activities, while inhibiting that of superoxide dismutase. This was associated with increased levels of total thiols and glutathione along with a decreased level of oxidized glutathione in leaves. Moreover, GA pre-soaking led to changes in leaf fatty acid composition of seedlings challenged with Cd, as evidenced by the higher total lipid content and lipid unsaturation degree. As a whole, this study provides strong arguments highlighting the potential role of GA as a growth promoter for sunflower seedlings submitted to Cd stress, notably by boosting the antioxidant defense system and improving leaf membrane stability.


Assuntos
Antioxidantes/farmacologia , Cádmio/toxicidade , Ácido Gálico/farmacologia , Helianthus/efeitos dos fármacos , Ascorbato Peroxidases/metabolismo , Catalase/metabolismo , Tolerância a Medicamentos , Glutationa/metabolismo , Helianthus/crescimento & desenvolvimento , Helianthus/metabolismo , Metabolismo dos Lipídeos/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Brotos de Planta/efeitos dos fármacos , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/metabolismo , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Superóxido Dismutase/metabolismo
4.
Plant Physiol Biochem ; 159: 322-334, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33421908

RESUMO

Excess moisture in the form of waterlogging or full submergence can cause severe conditions of hypoxia or anoxia compromising several physiological and biochemical processes. A decline in photosynthetic rate due to accumulation of ROS and damage of leaf tissue are the main consequences of excess moisture. These effects compromise crop yield and quality, especially in sensitive species, such as soybean (Glycine max.). Phytoglobins (Pgbs) are expressed during hypoxia and through their ability to scavenge nitric oxide participate in several stress-related responses. Soybean plants over-expressing or suppressing the Pgb1 gene GmPgb1 were generated and their ability to cope with waterlogging and full submergence conditions was assessed. Plants over-expressing GmPgb1 exhibited a higher retention of photosynthetic rate during waterlogging and survival rate during submergence relative to wild type plants. The same plants also had lower levels of ROS due to a reduction in expression of Respiratory Burst Oxidase Homologs (RBOH), components of the NADPH oxidase enzyme, and enhanced antioxidant system characterized by higher expression of catalases (CAT) and superoxide dismutase (SOD), as well as elevated expression and activity of ascorbate peroxidase (APX). Plants over-expressing GmPgb1 also exhibited an expression pattern of aquaporins typical of excess moisture resilience. This was in contrast to plants downregulating GmPgb1 which were characterized by the lowest photosynthetic rates, higher ROS signal, and reduced expression and activities of many antioxidant enzymes. Results from these studies suggest that GmPgb1 exercises a protective role during conditions of excess moisture with similar mechanisms operating during waterlogging and submergence.


Assuntos
Fabaceae , Expressão Gênica , Proteínas de Plantas , Soja , Estresse Fisiológico , Antioxidantes , Ascorbato Peroxidases/genética , Ascorbato Peroxidases/metabolismo , Fabaceae/metabolismo , Fotossíntese , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Espécies Reativas de Oxigênio , Soja/genética , Soja/metabolismo , Estresse Fisiológico/genética , Água/química
5.
Ecotoxicol Environ Saf ; 209: 111772, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33316726

RESUMO

There are conclusive evidences of selenium (Se) deficiency in Brazilian soils and foods. Brazil is the largest producer and consumer of coffee worldwide, which favors agronomic biofortification of its coffee. This study aimed to evaluate effects of foliar application of three formulations and six rates of Se on antioxidant metabolism, agronomic biofortification and yield of coffee beans. Seven Se concentrations (0, 10, 20, 40, 80, 100 and 160 mg L-1) were applied from three formulations of Se (sodium selenate, nano-Se 1500, and nano-Se 5000). Selenium application up to 40 mg L-1 increased the concentration of photosynthetic pigments such as chlorophylls, pheophytins and carotenoids in coffee leaves. Foliar application of Se ranging from 20 to 80 mg L-1 decreased lipid peroxidation and concentration of hydrogen peroxide, but increased superoxide dismutase, ascorbate peroxidase, catalase and glutathione reductase activities in coffee leaves. These results indicated that foliar Se application stimulates antioxidative metabolism to mitigate reactive oxygen species. Foliar application of 20 mg Se L-1 of sodium selenate increased coffee yield by 38%, and 160 mg Se L-1 of nano-Se 5000 increased dramatically coffee yield by 42%. Selenium concentration in grains ranged from 0.116 to 4.47 mg kg-1 (sodium selenate), 4.84 mg kg-1 (nano-Se 1500) and 5.82 mg kg-1 (nano-Se 5000). The results suggest the beneficial effect of Se on the increment of photosynthetic pigments, antioxidative metabolism, increased coffee yield and nutritional quality of grains. The recommended foliar Se application in this study can mitigate abiotic stressors such as high temperatures resulting in higher yield of coffee plants.


Assuntos
Antioxidantes/farmacologia , Café/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Selênio/farmacologia , Antioxidantes/metabolismo , Ascorbato Peroxidases/metabolismo , Biofortificação/métodos , Catalase/metabolismo , Clorofila/metabolismo , Coffea , Peroxidação de Lipídeos , Oxirredução , Fotossíntese/efeitos dos fármacos , Folhas de Planta/metabolismo , Ácido Selênico/metabolismo , Superóxido Dismutase/metabolismo
6.
Food Chem ; 338: 128044, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32932092

RESUMO

The effects of preharvest treatments with 0.1 mM methyl jasmonate (MeJA) and 0.5 mM salicylic acid (SA) on quality parameters of lemon fruit and their relationship with antioxidant systems, gene expression and bioactive compounds at harvest and during cold storage were evaluated. Results showed that total antioxidant activity, total phenolic content and the major individual phenolics (hesperidin and eriocitrin) were always higher in treated fruit than in controls. The activity of the antioxidant enzymes catalase, peroxidase and ascorbate peroxidase was also increased at harvest by SA and MeJA treatments, especially the last enzyme, for which the expression of its codifying gene was also enhanced. In addition, treated fruit had lower weight and firmness losses, respiration rate and production of ethylene than controls. Moreover, sugars and organic acids were maintained at higher concentration in flavedo and juice as a consequence of preharvest SA and MeJA treatments, showing an effect on maintaining fruit quality properties.


Assuntos
Acetatos/farmacologia , Antioxidantes/metabolismo , Citrus/efeitos dos fármacos , Ciclopentanos/farmacologia , Armazenamento de Alimentos/métodos , Oxilipinas/farmacologia , Ácido Salicílico/farmacologia , Ascorbato Peroxidases/metabolismo , Catalase/metabolismo , Citrus/química , Citrus/metabolismo , Temperatura Baixa , Frutas/química , Frutas/efeitos dos fármacos , Frutas/metabolismo , Peroxidase/metabolismo , Fenóis/análise
7.
Chemosphere ; 262: 128388, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182095

RESUMO

Arbitrary use of insecticides in agricultural practices cause severe environmental hazard that adversely affects the growth and productivity of edible crops. Considering theses, the aim of the present study was to evaluate the toxicological potential of two neonicotinoid insecticides, imidacloprid (IMID) and thiamethoxam (THIA) using chickpea as a test crop. Application of insecticides at three varying doses revealed a gradual decrease in biological performance of chickpea plants which however, varied noticeably among insecticides and their doses. Significant (P ≤ 0.05) decline in germination efficiency, length of plant organs under in vitro condition was observed in a dose related manner. Among insecticides, 300 µgIMIDkg-1 (3X dose) maximally and significantly (P ≤ 0.05) inhibited germination efficiency, vigor index, length, dry matter accumulation, photosynthetic pigment formation, nodule volume and mass, nutrient uptake, grain yield and protein over untreated control. In contrast, 75 µgTHIAkg-1 (3X dose) considerably declined the leghaemoglobin content, shoot phosphorus and root nitrogen. Enhanced expression of stress biomarkers including proline, malondialdehyde (MDA), and antioxidant defence enzymes was noticed in the presence of insecticides. For instance, at 3X IMID, shoot proline, MDA, ascorbate peroxidase (APX), guaiacol peroxidase (GPX) and peroxidase (POD) were increased significantly (P ≤ 0.05) by 66%, 81%, 36% and 35%, respectively. Additionally, electrolyte leakage was maximally (77%) increased at 3X dose of IMID, whereas, H2O2 in foliage was maximally accumulated (0.0156 µ moles min-1 g-1 fw) at 3X dose of THIA which was 58% greater than untreated foliage. A clear distortion/damage in tip and surface of roots and ultrastructural deformation in xylem and phloem of plant tissues as indication of insecticidal phytotoxicity was observed under scanning electron microscope (SEM). For oxidative stress and cytotoxicity assessment, root tips were stained with a combination of acridine orange and propidium iodide, and Evan blue dyes and examined. Confocal laser scanning microscopic (CLSM) images of roots revealed a 10-fold and 13.5-fold increase in red and blue fluorescence when 3X IMID treated roots were assessed quantitatively. Conclusively, the present investigation recommends that a careful and protected approach should be adopted before the application of insecticides in agricultural ecosystems.


Assuntos
Cicer/fisiologia , Inseticidas/toxicidade , Neonicotinoides/toxicidade , Antioxidantes/metabolismo , Ascorbato Peroxidases/metabolismo , Cicer/enzimologia , Ecossistema , Germinação , Peróxido de Hidrogênio/metabolismo , Inseticidas/metabolismo , Malondialdeído/metabolismo , Nitrocompostos , Estresse Oxidativo , Peroxidase , Fotossíntese
8.
Chemosphere ; 262: 128384, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182105

RESUMO

Arsenic (As) polluted food chain has become a serious issue for the growth and development of humans, animals and plants. Nitric oxide (NO) or silicon (Si) may mitigate As toxicity. However, the combined application of NO and Si in mitigating As uptake and phytotoxicity in Brassica juncea is unknown. Hence, the collegial effect of sodium nitroprusside (SNP), a NO donor and Si application on B. juncea growth, gas exchange parameters, antioxidant system and As uptake was examined in a greenhouse experiment. Arsenic toxicity injured cell membrane as signposted by the elevated level of malondialdehyde (MDA) and hydrogen peroxide (H2O2), thus decreasing the growth of stressed plants. Moreover, As stress negatively affected gas exchange parameters and antioxidative system of plants. However, NO or/and Si alleviated As induced oxidative stress through increasing the activity of superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR), glutathione S-transferase (GST), glutathione (GSH), along with thiol and proline synthesis. Furthermore, plants treated with co-application of NO and Si showed improved growth, gas attributes and decreased As uptake under As regimes. The current study highlights that NO and Si synergistically interact to mitigate detrimental effects of As stress through reducing As uptake. Our findings recommend combined NO and Si application in As spiked soils for improvement of plant growth and stress alleviation.


Assuntos
Arsênico/metabolismo , Mostardeira/fisiologia , Óxido Nítrico/química , Silício/química , Poluentes do Solo/metabolismo , Antioxidantes/metabolismo , Arsênico/toxicidade , Ascorbato Peroxidases/metabolismo , Glutationa/metabolismo , Glutationa Redutase/metabolismo , Peróxido de Hidrogênio/metabolismo , Malondialdeído/metabolismo , Mostardeira/metabolismo , Doadores de Óxido Nítrico/metabolismo , Doadores de Óxido Nítrico/farmacologia , Nitroprussiato/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Plântula/efeitos dos fármacos , Poluentes do Solo/toxicidade , Superóxido Dismutase/metabolismo
9.
PLoS One ; 15(12): e0243537, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33320882

RESUMO

Understanding the relationship between exogenous melatonin and water deficit stress is crucial for alleviating the effects of water deficit stress at germination stage of soybean (Glycine max (L.) Merrill) in agriculture. This study investigated the effects of exogenous melatonin on soybean antioxidant properties and cell ultrastructure under water deficit stress induced by polyethylene glycol (PEG) 6000. The drought-sensitive soybean variety Suinong 26 was used as the material to study the effects of different concentrations of melatonin (0, 300, 500 µmol·L-1) soaking soybean seeds under drought stress (PEG-6000: 3% and 6%). The results showed that the germination rate (GR), germination potential (GP), germination index (GI) and radicle shape of soybean were affected negatively to different degrees under PEG stress. Moreover, stress induced by different PEG concentrations overproduced the content of reactive oxygen species (H2O2, O2·-) in cells, leading to increased lipid membrane peroxidation as electrolyte leakage (EL) and malondialdehyde (MDA) content, which resulted in impaired cell integrity. However, after seeds soaking with melatonin, the lipid peroxidation of the cell membrane was reduced, and the activities of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) further increased to minimize the excessive generation of ROS. Similar results were obtained for soluble protein and proline, that may help in regulating the osmotic pressure and maintain cellular integrity. With the interaction of these enzymes, compared with 300 µmol·L-1 melatonin, 500 µmol·L-1 melatonin could more effective to remove the ROS and reduce cell peroxidation. Overall, 500 µmol·L-1 melatonin performed better than 300 µmol·L-1. In conclusion, the seed soaking with melatonin promoted the germination of soybean seeds under water stress.


Assuntos
Melatonina/metabolismo , Pressão Osmótica/fisiologia , Soja/metabolismo , Antioxidantes/metabolismo , Ascorbato Peroxidases/metabolismo , Catalase/metabolismo , Desidratação/metabolismo , Secas , Germinação/efeitos dos fármacos , Germinação/fisiologia , Peróxido de Hidrogênio/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Malondialdeído/metabolismo , Peroxidase/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Plântula/metabolismo , Sementes/metabolismo , Soja/fisiologia , Estresse Fisiológico/efeitos dos fármacos , Superóxido Dismutase/metabolismo
10.
Chemosphere ; 261: 127585, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32739687

RESUMO

The utilization of tungsten in traffic, smelting, mining, and other industrial applications allows its' accumulation in the environmental ecosystems. The present study included using a soluble form of tungsten (tungstate) at different levels (0, 1, 5, 10, 50, and 100 mg L-1) as a water contaminant. The germinating seeds experienced tungstate at 1-50 mg L-1 exhibited stimulation of seedling dry and fresh matter stress tolerance indices, whereas retardation of these traits at the level of 100 mg L-1 was manifested. The stimulation of seedling growth at the levels of 1-50 mg L-1 was associated with the regulation of reactive oxygen status, higher stability of cell membrane, and elevated level of antioxidative responses. Regarding the oxidative stress of the seedlings exposed to tungstate contaminated water, only the concentration of 100 mg L-1 induced accumulation of hydrogen peroxide, superoxide anion, and hydroxyl radical with apparent membrane deteriorations in terms of lipid peroxidation. Furthermore, reductions of phytochelatins, reduced glutathione, ascorbate, ascorbate peroxidase, glutathione peroxidase, as well as glutathione-S-transferase were the main symptoms of tungstate phytotoxicity at the same level. The accumulation of lignin, ionic peroxidase, soluble peroxidase, and lignin-related enzymes (phenylalanine ammonia-lyase and polyphenol oxidase) were the striking reasons for restricting seedlings growth at noxious tungstate level. The results could suggest that the elevated levels of defense systems, at least in part, were accountable for raising broccoli resistance against tungstate stress at low doses. Furthermore, these plants can grow in tungsten-polluted areas by modifying their physiological processes. However, this study shed the light to the eco-toxicity of tungstate and imparts evidence for the need to establishing environmental risk management of tungstate accumulation.


Assuntos
Antioxidantes/metabolismo , Brassica/fisiologia , Compostos de Tungstênio/toxicidade , Poluentes Químicos da Água/toxicidade , Ascorbato Peroxidases/metabolismo , Ácido Ascórbico/metabolismo , Brassica/metabolismo , Catalase/metabolismo , Ecossistema , Germinação , Glutationa/metabolismo , Oxirredução , Estresse Oxidativo , Plântula/metabolismo , Sementes/metabolismo , Superóxido Dismutase/metabolismo
11.
Ecotoxicol Environ Saf ; 202: 110916, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32800251

RESUMO

Selenium (Se) at low concentration is considered benefit element to plants. The range between optimal and toxic concentration of Se is narrow and varies among plant species. This study aimed to evaluate the phenotypic, physiological and biochemical responses of four rice genotypes (BRS Esmeralda, BRSMG Relâmpago, BRS Bonança and Bico Ganga) grown hydroponically treated with sodium selenate (1.5 mM L-1). Selenium treated plants showed a dramatically decrease of soluble proteins, chlorophylls, and carotenoids concentration, resulting in the visual symptoms of toxicity characterized as leaf chlorosis and necrosis. Selenium toxicity caused a decrease on shoot and root dry weight of rice plants. Excess Se increased the oxidative stress monitored by the levels of hydrogen peroxide and lipid peroxidation. The enzymatic antioxidant system (catalase, superoxide dismutase, and ascorbate peroxidase) increased in response to Se supply. Interestingly, primary metabolism compounds such as sucrose, total sugars, nitrate, ammonia and amino acids increased in Se-treated plants. The increase in these metabolites may indicate a defense mechanism for the osmotic readjustment of rice plants to mitigate the toxicity caused by Se. However, these metabolites were not effective to minimize the damages on phenotypic traits such as leaf chlorosis and reduced shoot and root dry weight in response to excess Se. Increased sugars profile combined with antioxidant enzymes activities can be an effective biomarkers to indicate stress induced by Se in rice plants. This study shows the physiological attributes that must be taken into account for success in the sustainable cultivation of rice in environments containing excess Se.


Assuntos
Oryza/fisiologia , Selênio/toxicidade , Poluentes do Solo/toxicidade , Antioxidantes/metabolismo , Ascorbato Peroxidases/metabolismo , Catalase/metabolismo , Clorofila/metabolismo , Peróxido de Hidrogênio/metabolismo , Hidroponia , Peroxidação de Lipídeos , Oryza/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Folhas de Planta/metabolismo , Ácido Selênico/metabolismo , Superóxido Dismutase/metabolismo
12.
PLoS One ; 15(6): e0220598, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32579545

RESUMO

Roof greening is an important national policy for maintaining the hydrological balance in China; however, plant growth is limited by drought stress. This study aims to identify strong drought resistant plant species for roof greening from ten common species: Paeonia lactiflora, Hemerocallis dumortieri, Meehania urticifolia, Iris lactea var. chinensis, Hylotelephium erythrostictum, Sedum lineare, Iris germanica, Cosmos bipinnata, Hosta plantaginea, and Dianthus barbatus. By controlling the soil relative water content (RWC), we designed three treatments: moderate drought stress (40±2% < RWC < 45±2%), severe drought stress (RWC < 30±2%) and well-watered control (RWC > 75±2%). After the seedlings were provided different levels of water, their membrane permeability (MP), chlorophyll concentration (Chl), and superoxide dismutase (SOD), peroxidase (POD) and ascorbate peroxidase (APX) activity were measured. Finally, the membership function method was used to assess the drought resistance of these species. The results showed that C. bipinnata and M. urticifolia were not suitable for moderate or severe drought stress and did not survive. The other species presented variations in physiological and biochemical parameters. The MP of He. dumortieri, I. lactea and Ho. plantaginea showed minor changes between the well-watered control and drought stress. Most of the species showed reduced SOD activity under moderate drought stress but increased activity under severe stress. All of the plant species showed decreases in the protective enzymes POD and APX with increasing drought stress. The membership function method was applied to calculate the plant species' drought resistance, and the following order of priority of the roof-greening plant species was suggested: He. dumortieri > I. germanica > I. lactea > D. barbatus > Hy. erythrostictum > S. lineare > Ho. plantaginea > P. lactiflora.


Assuntos
Secas , Fenômenos Fisiológicos Vegetais , Plântula/fisiologia , Estresse Fisiológico , Ascorbato Peroxidases/metabolismo , Permeabilidade da Membrana Celular , Clorofila/metabolismo , Peroxidases/metabolismo , Plântula/metabolismo , Solo/química , Superóxido Dismutase/metabolismo , Análise de Sobrevida , Água/análise
13.
Ecotoxicol Environ Saf ; 202: 110890, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32593096

RESUMO

The presence of tetracycline is ubiquitous and has adverse effects on aquatic systems. A hydroponic experiment was conducted to investigate the ecological sensitivity of Hydrocharis dubia (Bl.) Backer and Trapa bispinosa Roxb. Exposed to different concentrations of tetracycline (0, 0.1, 1, 10, 30 and 50 mg/L) for one day (1D) and 14 days (14D). The results showed that after 1D of tetracycline exposure, the physiological indices of H. dubia had no remarkable change except for proline which was significantly stimulated under 0.1 mg/L tetracycline. For T. bispinosa, guaiacol peroxidase (POD), polyphenol oxidase (PPO) and ascorbate peroxidase (APX) activity and protein and proline content were notably promoted under different concentrations of tetracycline, but PPO activity was significantly decreased in 50 mg/L. After 14D, tetracycline caused no harm to the growth and protein content of H. dubia, but negatively influenced lipid peroxidation product and chlorophyll content in H. dubia under high tetracycline concentrations. Superoxide dismutase (SOD) and POD activity of H. dubia significantly increased at high tetracycline concentrations, while catalase (CAT) and PPO activity significantly decreased. APX activity in H. dubia increased with tetracycline concentrations at low tetracycline concentrations. For T. bispinosa, high concentrations of tetracycline application significantly inhibited its growth and the content of protein and chlorophyll. SOD, POD, CAT, and PPO activity of T. bispinosa were induced under different concentrations of tetracycline and no lipid peroxidation was observed. APX activity in T. bispinosa was significantly inhibited at high tetracycline concentrations. The results suggest that tetracycline can cause oxidative damage in H. dubia but harm the metabolism process of T. bispinosa without inducing oxidative damage. Overall, the sensitivity of T. bispinosa exposed to tetracycline exposure is higher than that of H. dubia.


Assuntos
Antibacterianos/toxicidade , Hydrocharitaceae/fisiologia , Tetraciclina/toxicidade , Antioxidantes/metabolismo , Ascorbato Peroxidases/metabolismo , Catalase/metabolismo , Clorofila/metabolismo , Hydrocharitaceae/efeitos dos fármacos , Peroxidação de Lipídeos/efeitos dos fármacos , Lythraceae , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Peroxidase , Prolina/metabolismo , Superóxido Dismutase/metabolismo
14.
Ecotoxicol Environ Saf ; 201: 110777, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32485493

RESUMO

Selenium (Se) is a beneficial element to higher plants. Application of Se at low concentrations enhances the antioxidant metabolism reducing the reactive oxygen species (ROS) generated by plant membrane cells. This study aimed to evaluate how the application of Se in the forms sodium selenate and sodium selenite regulates ROS scavenging in field-grown cowpea plants. Seven Se application rates (0; 2.5; 5; 10; 20; 40 and 60 g ha-1) of each of the two Se forms were applied to plants via the soil. Photosynthetic pigments concentration, gas exchange parameters, lipid peroxidation by malondialdehyde (MDA) concentration, hydrogen peroxide concentration, activity of catalase (CAT, EC:1.11.1.6), glutathione reductase (GR, EC:1.6.4.2), ascorbate peroxidase (APX, EC:1.11.1.11) and Se concentration in leaves and grains were evaluated. In general, Se application led to a decrease in chlorophyll a concentration whilst leading to an increase in chlorophyll b, indicating conservation of total chlorophyll concentration. Application of 2.5 g ha-1 of Se as selenate provided a notable increase in total chlorophyll and total carotenoids compared to the other application rates. Selenate and selenite application decreased lipid peroxidation. However, each Se source acted in a different pathway to combat ROS. While selenate showed more potential to increase activity of APX and GR, selenite showed a higher potential to increase CAT activity. The negative correlation between CAT and GR is indicative that both pathways might be activated under distinct circumstances. The more prominent activity of CAT under high rates of selenite resulted in a negative correlation of this enzyme with chlorophyll a and carotenoids. Both selenate and selenite application increased sucrose and total sugars concentration in leaves of cowpea plants. Overall, these results indicate that application of Se in cowpea under field conditions stimulates distinct pathways to scavenge ROS. This could prove beneficial to mitigate oxidative stress during plant development.


Assuntos
Espécies Reativas de Oxigênio/metabolismo , Ácido Selênico/toxicidade , Ácido Selenioso/toxicidade , Vigna/efeitos dos fármacos , Antioxidantes/metabolismo , Ascorbato Peroxidases/metabolismo , Catalase/metabolismo , Clorofila , Clorofila A , Glutationa Redutase/metabolismo , Fotossíntese , Folhas de Planta/metabolismo , Ácido Selênico/metabolismo , Ácido Selenioso/metabolismo , Selênio/metabolismo , Selenito de Sódio , Vigna/metabolismo , Vigna/fisiologia
15.
PLoS One ; 15(4): e0232228, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32353077

RESUMO

Heat stress is one of the major abiotic stresses that impair plant growth and crop productivity. Plant growth-promoting endophytic bacteria (PGPEB) and humic acid (HA) are used as bio-stimulants and ecofriendly approaches to improve agriculture crop production and counteract the negative effects of heat stress. Current study aimed to analyze the effect of thermotolerant SA1 an isolate of Bacillus cereus and HA on tomato seedlings. The results showed that combine application of SA1+HA significantly improved the biomass and chlorophyll fluorescence of tomato plants under normal and heat stress conditions. Heat stress increased abscisic acid (ABA) and reduced salicylic acid (SA) content; however, combined application of SA1+HA markedly reduced ABA and increased SA. Antioxidant enzymes activities revealed that SA1 and HA treated plants exhibited increased levels of ascorbate peroxidase (APX), superoxide dismutase (SOD), and reduced glutathione (GSH). In addition, heat stress markedly reduced the amino acid contents; however, the amino acids were increased with co-application of SA1+HA. Similarly, inductively-coupled plasma mass-spectrometry results showed that plants treated with SA1+HA exhibited significantly higher iron (Fe+), phosphorus (P), and potassium (K+) uptake during heat stress. Heat stress increased the relative expression of SlWRKY33b and autophagy-related (SlATG5) genes, whereas co-application of SA1+HA augmented the heat stress response and reduced SlWRKY33b and SlATG5 expression. The heat stress-responsive transcription factor (SlHsfA1a) and high-affinity potassium transporter (SlHKT1) were upregulated in SA1+HA-treated plants. In conclusion, current findings suggest that co-application with SA1+HA can be used for the mitigation of heat stress damage in tomato plants and can be commercialized as a biofertilizer.


Assuntos
Bacillus cereus/metabolismo , Lycopersicon esculentum/crescimento & desenvolvimento , Lycopersicon esculentum/metabolismo , Proteínas de Plantas/metabolismo , Plântula/metabolismo , Termotolerância/fisiologia , Aminoácidos/metabolismo , Antioxidantes/metabolismo , Ascorbato Peroxidases/metabolismo , Regulação da Expressão Gênica de Plantas/fisiologia , Glutationa/metabolismo , Resposta ao Choque Térmico/fisiologia , Substâncias Húmicas , Estresse Fisiológico/fisiologia , Superóxido Dismutase/metabolismo
16.
Ecotoxicol Environ Saf ; 200: 110747, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32460052

RESUMO

The presence of surfactants may affect the bioavailability of polycyclic aromatic hydrocarbons. A hydroponic experiment was conducted to investigate the response of Hydrocharis dubia (Bl.) Backer to different concentrations of linear alkylbenzene sulfonate (LAS), naphthalene (NAP) and their mixture (0.5, 5, 10, and 20 mg/L) for 14 days and 28 days. The results showed that LAS had a greater toxic effect on H. dubia growth than NAP at treatment concentrations of 0.5-20 mg/L. The combined effect of LAS and NAP was damaging to H. dubia at concentrations of LAS + NAP ≥5 + 5 mg/L. When LAS + NAP ≥10 + 10 mg/L, the underground parts of H. dubia suffered more significant damage than the aboveground parts. Under the treatments with LAS, NAP and their mixture, H. dubia experienced oxidative stress. Soluble proteins and antioxidant enzymes were the main substances protecting H. dubia from LAS stress, and superoxide dismutase (SOD) and peroxidase (POD) were the main protective enzymes. When exposed to NAP, H. dubia growth was stimulated and promoted at the same time. In the short-term treatment (14 d), catalase (CAT) activity was sensitive to NAP stimulation, and soluble proteins and SOD were the main protective substances produced. Soluble sugars, SOD and ascorbate peroxidase (APX) played important protective roles during the longer exposure time (28 d). The physiological response of H. dubia exposed to the combined toxicants was weaker than the response to exposure to individual toxicants. The responses of SOD and CAT activity were positive in the short term (14 d), and these were the main protective enzymes. As the exposure time increased (28 d), the plant antioxidant system responded negatively.


Assuntos
Ácidos Alcanossulfônicos/toxicidade , Hydrocharitaceae/efeitos dos fármacos , Naftalenos/toxicidade , Tensoativos/toxicidade , Ácidos Alcanossulfônicos/antagonistas & inibidores , Antioxidantes/metabolismo , Ascorbato Peroxidases/metabolismo , Catalase/metabolismo , Sinergismo Farmacológico , Hydrocharitaceae/enzimologia , Hydrocharitaceae/metabolismo , Naftalenos/antagonistas & inibidores , Estresse Oxidativo/efeitos dos fármacos , Peroxidase/metabolismo , Superóxido Dismutase/metabolismo
17.
Chemosphere ; 251: 126366, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32145575

RESUMO

In this study, the effects of excess nickel (Ni) (100 µM and 200 µM) on growth, antioxidant production, fatty acid, organic and amino acids profiles were examined in Lemna minor L. After 7 days of Ni treatment, chlorosis, growth inhibition and ROS overproduction were observed, accompanied by Ni accumulation. Interestingly, decreased malondialdehyde (MDA) levels were recorded in fronds upon Ni exposure. Fatty acid profiles in Ni-treated L. minor were characterized by increases in saturated- and decreases in unsaturated fatty acids. Ni excess increased the activities of antioxidant enzymes such as superoxide dismutase (SOD), guiacol peroxidase (GPX), and glutathione reductase (GR), and non-enzymatic antioxidants such as glutathione (GSH) and ascorbic acid (AsA); however, deactivation of ascorbate peroxidase (APX) and catalase (CAT) activities were also observed. Disruption of amino acid metabolism in Ni-exposed fronds was evidenced by the accumulation of cysteine, arginine, threonine, valine, isoleucine, leucine, lysine and phenylalanine, as well as reduced levels of tyrosine, alanine, aspartate and proline. Approximately 299%-396%, 139%-254% and 56%-97% concentration increments in citric, malic and oxalic acids, respectively, were concomitantly observed with significant decreases in tartaric, acetic, and fumaric acids in fronds subjected to Ni stress. Taken together, these results indicated that Ni stress induced negative effects on plant physiological, biochemical and morphological processes; however, it is likely that the coordination of metabolites and antioxidants may ameliorate the damaging effects of Ni accumulation.


Assuntos
Araceae/metabolismo , Níquel/metabolismo , Antioxidantes/metabolismo , Araceae/efeitos dos fármacos , Ascorbato Peroxidases/metabolismo , Ácido Ascórbico/farmacologia , Catalase/metabolismo , Ácidos Graxos/metabolismo , Glutationa/metabolismo , Glutationa Redutase/metabolismo , Malondialdeído/metabolismo , Oxirredução , Peroxidase/metabolismo , Peroxidases/metabolismo , Prolina/metabolismo , Superóxido Dismutase/metabolismo
18.
Ecotoxicol Environ Saf ; 193: 110355, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32120164

RESUMO

In the Montado system, in Portuguese Alentejo region, some Eutric Cambisols are known to promote manganese (Mn) toxicity in wheat. Variation on bioavailable Mn concentration depends on soil acidity, which can be increased by natural events (e.g. waterlogging) or human activity (e.g. excess use of chemical fertilizers). The effect of increasing soil Mn on crop element uptake, element distribution and oxidative stress was evaluated on winter wheat (Triticum aestivum). Plants were grown for 3 weeks in an acidic Cambisol spiked with increasing Mn concentrations (0, 45.2 and 90.4 mg MnCl2/Kg soil). Calcium (Ca), phosphorus (P), magnesium (Mg) and Mn were quantified in the soil solution, root and shoot tissues and respective subcellular fractions. The activity of the antioxidant enzymes ascorbate peroxidase (APX), catalase (CAT), glutathione reductase (GR), guaiacol peroxidase (GPX) and superoxide dismutase (SOD) were determined in extracts of wheat shoots and roots. Overall, increase in soil bioavailable Mn inhibited the uptake of other elements, increased the Ca proportion in the root apoplast, promoted the translocation of Mn and P to shoot tissues and increased their proportion in the shoot vacuoles. Wheat roots showed greater antioxidant enzymes activities than shoots. These activities decreased at the highest soil Mn concentration in both plant parts. Wheat roots appear to be more sensitive to oxidative stress derived from excess soil Mn and promote Mn translocation and storage in shoot vacuoles, probably in Mn and P complexes, as a detoxification strategy. Improvement in wheat production, in acidic soils, may rely on the enhancement of its Mn detoxification strategies.


Assuntos
Manganês/toxicidade , Poluentes do Solo/toxicidade , Triticum/efeitos dos fármacos , Antioxidantes/metabolismo , Ascorbato Peroxidases/metabolismo , Transporte Biológico , Cálcio/metabolismo , Catalase/metabolismo , Glutationa Redutase/metabolismo , Magnésio/metabolismo , Manganês/farmacocinética , Estresse Oxidativo , Peroxidase/metabolismo , Fósforo/metabolismo , Solo/química , Poluentes do Solo/farmacocinética , Superóxido Dismutase/metabolismo , Triticum/enzimologia , Triticum/metabolismo
19.
Ecotoxicol Environ Saf ; 195: 110469, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32179235

RESUMO

To explore the mechanism of how lead (Pb) and cadmium (Cd) stress affects photosynthesis of mulberry (Morus alba L.), we looked at the effects of different concentrations of Pb and Cd stress (at 100 and 200 µmol L-1), which are two heavy metal elements, on leaf chlorophyll (Chl), photosynthesis gas exchange, Chl fluorescence, and reactive oxygen species (ROS) metabolism in mulberry leaves. The results showed that higher concentrations of Pb and Cd reduced leaf Chl content, especially in Chl a where content was more sensitive than in Chl b. Under Pb and Cd stress, the photosynthetic carbon assimilation capacity of mulberry leaves was reduced, which was a consequence of combined limitations of stomatal and non-stomatal factors. The main non-stomatal factors were decreased photosystem II (PSII) and photosystem I (PSI) activity and carboxylation efficiency (CE). Damage to the donor side of the PSII reaction center was greater than the acceptor side. After being treated with 100 µmol L-1 of Pb and Cd, mulberry leaves continued to be able to dissipate excess excitation energy by starting non-photochemical quenching (NPQ), but when Pb and Cd concentrations were increased to 200 µmol L-1, the protection mechanism that depends on NPQ was impaired. Excessive excitation energy from chloroplasts promoted a great increase of ROS, such as superoxide anion (O2•-) and H2O2. Moreover, under high Pb and Cd stress, superoxide dismutase (SOD) and ascorbate peroxidase (APX) were also inhibited to some extent, and excessive ROS also resulted in a significantly higher degree of oxidative damage. Compared with Cd, the effect of Pb stress at the same concentration level displayed a significantly lower impact on Chl content, photosynthetic carbon assimilation, and stomatal conductance. Meanwhile, Pb stress mainly damaged activity of the oxygen-evolving complex (OEC) located on PSII donor side, but it reduced the electronic pressure on the PSII acceptor side and PSI. Furthermore, under Pb stress, the NPQ, SOD, and APX activity were all significantly higher than those under Cd stress. Thus under Pb stress, the degree of photoinhibition and oxidative damage of PSII and PSI in mulberry leaves were significantly lower than under Cd stress.


Assuntos
Cádmio/toxicidade , Chumbo/toxicidade , Morus/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Ascorbato Peroxidases/metabolismo , Clorofila/metabolismo , Cloroplastos/efeitos dos fármacos , Cloroplastos/metabolismo , Peróxido de Hidrogênio/metabolismo , Morus/enzimologia , Morus/metabolismo , Fotossíntese/efeitos dos fármacos , Complexo de Proteína do Fotossistema I/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Plântula/efeitos dos fármacos , Plântula/metabolismo , Superóxido Dismutase/metabolismo
20.
Science ; 367(6484): 1372-1376, 2020 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-32193327

RESUMO

The structural and functional complexity of multicellular biological systems, such as the brain, are beyond the reach of human design or assembly capabilities. Cells in living organisms may be recruited to construct synthetic materials or structures if treated as anatomically defined compartments for specific chemistry, harnessing biology for the assembly of complex functional structures. By integrating engineered-enzyme targeting and polymer chemistry, we genetically instructed specific living neurons to guide chemical synthesis of electrically functional (conductive or insulating) polymers at the plasma membrane. Electrophysiological and behavioral analyses confirmed that rationally designed, genetically targeted assembly of functional polymers not only preserved neuronal viability but also achieved remodeling of membrane properties and modulated cell type-specific behaviors in freely moving animals. This approach may enable the creation of diverse, complex, and functional structures and materials within living systems.


Assuntos
Compostos de Anilina/química , Ascorbato Peroxidases/genética , Engenharia Genética , Neurônios/fisiologia , Nitrocompostos/química , Fenilenodiaminas/química , Polímeros/química , Potenciais de Ação , Animais , Ascorbato Peroxidases/metabolismo , Caenorhabditis elegans , Membrana Celular/metabolismo , Sobrevivência Celular , Células Cultivadas , Condutividade Elétrica , Células HEK293 , Hipocampo , Humanos , Potenciais da Membrana , Camundongos , Neurônios Motores/fisiologia , Células Musculares/fisiologia , Neurônios/enzimologia , Técnicas de Patch-Clamp , Polímeros/metabolismo , Ratos , Transdução Genética
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