Exogenous Application Of Hydrogen Peroxide Research Articles

Salt stress and exogenous application of hydrogen peroxide on photosynthetic parameters of soursop

ABSTRACT This study aimed to evaluate the gas exchanges and photosynthetic pigments of soursop seedlings cv. ‘Morada Nova’ irrigated with saline waters and subjected to exogenous application of hydrogen peroxide by seed soaking and foliar spraying. The study was carried out using plastic bags under greenhouse conditions at the Center of Technology and Natural Resources of the Federal University of Campina Grande, PB, Brazil, using a eutrophic Regolithic Neosol of sandy loam texture. Treatments were arranged in a randomized block design, in 5 x 5 factorial scheme, which consisted of five levels of electrical conductivity – ECw (0.7; 1.4; 2.1; 2.8 and 3.5 dS m-1) of irrigation water and five concentrations of hydrogen peroxide - H2O2 (0, 25, 50, 75 and 100 µM), with four replicates and three plants per plot. As the salt stress increased, there were reductions in internal CO2 concentration, instantaneous carboxylation efficiency and water use efficiency, and instantaneous carboxylation efficiency was the most sensitive variable. Hydrogen peroxide at concentrations of 25 and 50 µM attenuated the deleterious effects of water salinity on stomatal conductance, CO2 assimilation rate and chlorophyll a content, and the concentration of 25 µM was the most efficient. The content of chlorophyll b and carotenoids of soursop cv. ‘Morada Nova’ had the deleterious effects caused by the salinity of irrigation water mitigated by the exogenous application of hydrogen peroxide in the concentration of 25 μM.

Effects of saline water and exogenous application of hydrogen peroxide (H2O2) on Soursop (Annona muricata L.) at vegetative stage

Soursop is a fruit of great socioeconomic importance for the northeastern region of Brazil. However, the quantitative and qualitative limitation of the water resources of this region has reduced its production. The objective of this study was to evaluate the growth of ‘Morada Nova’ soursop plants irrigated with saline water and subjected to exogenous application of hydrogen peroxide through seed immersion and foliar spray. The study was conducted in plastic pots adapted as lysimeters, using a eutrophic Regolithic Neosol with sandy loam texture under greenhouse conditions. Treatments were distributed in randomized blocks, in a 4 x 4 factorial arrangement, corresponding to four levels of irrigation water electrical conductivity – ECw (0.7; 1.7; 2.7 and 3.7 dS m-1) and four concentrations of hydrogen peroxide – H2O2 (0, 25, 50 and 75 µM), with three replicates and one plant per plot. Foliar applications of H2O2 began 15 days after transplanting (DAT) and were carried out every 15 days at 17:00 h, after the sunset, by manually spraying the H2O2 solutions with a sprayer in such a way to completely wet the leaves (spraying the abaxial and adaxial faces). Treatment effects were evaluated based on plant height (PH), stem diameter (SD), number of leaves (NL) and leaf area (LA) at 60 and 90 DAT, and dry phytomass of leaves (LDP), stem (SDP), roots (RDP) and total (TDP) and leaf succulence (LS) at 90 DAT. Irrigation using water with estimated ECw of 1.55 dS m-1 caused acceptable mean reduction of 10% in soursop growth. Increasing concentrations of hydrogen peroxide did not attenuate the effects of salinity on plant height and leaf area during the vegetative stage. Hydrogen peroxide concentration of 20 µM led to higher leaf succulence in soursop plants.

Gas exchanges and growth of passion fruit seedlings under salt stress and hydrogen peroxide1

ABSTRACT The semi-arid region of the Brazilian Northeast has adequate edaphoclimatic conditions for the passion fruit production, but the water used for irrigation commonly has high concentrations of salts that are harmful to the plant growth and development. A previous supply of hydrogen peroxide induces the acclimation of plants under saline stress conditions, reducing deleterious effects on their growth and physiology. This study aimed to evaluate the gas exchanges and growth of passion fruit as a function of irrigation with saline water and exogenous application of hydrogen peroxide. The experiment was carried out under greenhouse conditions, using a randomized block design, in a 4 x 4 factorial arrangement, being four levels of irrigation water electrical conductivity (0.7 dS m-1, 1.4 dS m-1, 2.1 dS m-1 and 2.8 dS m-1) and four hydrogen peroxide concentrations (0 µM, 25 µM, 50 µM and 75 µM), with four replicates and two plants per plot. The hydrogen peroxide application attenuated the deleterious effects of the irrigation water salinity on transpiration, CO2 assimilation rate, internal carbon concentration, plant height and leaf area of yellow passion fruit, at 60 days after sowing, with the concentration of 25 µM being the most efficient. Irrigation using water with electrical conductivity above 0.7 dS m-1 negatively affects the gas exchanges and growth of passion fruit, being the stomatal conductance and leaf area the most sensitive variables to the salt stress.

Production and postharvest quality of yellow passion fruit cultivated with saline water and hydrogen peroxide

The present study aimed to evaluate the production and postharvest quality of yellow passion fruit, cultivated under different levels of irrigation water salinity and exogenous application of hydrogen peroxide. At low concentrations, hydrogen peroxide may favor plant acclimatization when subjected to saline stress conditions due to the activation of defense mechanisms. The experiment was conducted in greenhouse in the municipality of Campina Grande-PB, Brazil, using drainage lysimeters filled with sandy loam Entisol. The experimental design was randomized blocks, with 4×4 factorial arrangement with three replicates, consisting of four levels of irrigation water electrical conductivity—ECw (0.7, 1.4, 2.1 and 2.8 dS m-1) and four concentrations of hydrogen peroxide—H2O2 (0, 20, 40 and 60 μM). The different concentrations of H2O2 were applied by soaking the seeds for a 24-h period before sowing and spraying the leaves on the adaxial and abaxial sides. At the end of the cycle (205 days after transplanting-DAT), passion fruit production was evaluated by determining the number of fruits per plant, mean fruit weight and total fruit weight. Postharvest quality was determined by physical characterization of fruit (equatorial and polar diameters and rind and pulp thicknesses), hydrogen potential in the pulp, titratable acidity and ascorbic acid. Increasing levels of irrigation water salinity negatively affected the production and physical and chemical quality of passion fruits. Number and total weight of fruits per plant were the most compromised variables. There was significant interaction between irrigation water salinity levels and H2O2 concentrations on fruits’ polar diameter, at 205 days after transplanting. Foliar application at estimated concentration of 27.5 and 41.5 μM H2O2 led to the highest values of total titratable acidity and vitamin C, respectively, at 205 DAT. Water salinity above 0.7 dS m-1 resulted in changes in the physico-chemical characteristics of passion fruit. Peroxide concentrations up to 60 μM did not mitigate the deleterious effects of salt stress on passion fruit yield and quality in the first crop cycle.

Hydrogen peroxide protects pepper (Capsicum annuum L.) against pepper golden mosaic geminivirus (PepGMV) infections

Hydrogen peroxide is an important signal molecule in plant defense against biotic and abiotic stress. Pepper golden mosaic virus (PepGMV) is a whitefly-transmitted geminivirus causing significant yield and quality losses in pepper and other horticultural crops in Mexico. Several pesticides have been used trying to control whiteflies and thus, PepGMV disease in host crops. The present work examined the effect of exogenous application of hydrogen peroxide (H2O2) on inducing resistance to PepGMV infection in pepper plants. Experiments were carried out under greenhouse conditions aiming to evaluate phenotypical, biochemical and molecular features in these pepper plants. Hydrogen peroxide at 6, 14 and 18 mM induced tolerance to PepGMV either by absence of symptoms as well as by attenuating and/or delaying them. The protection observed was directly dependent on the concentration of H2O2 sprayed on plants. Moreover, PepGMV DNA levels were inversely proportional to the protection level. Enzymatic and gene expression profiles related with plant defense were induced in protected, in comparison to susceptible control plants. Interestingly, the levels of some phenolic compounds were also associated with plant protection. Taking together, these results suggested that exogenous foliar applications of H2O2 protect pepper plants against PepGMV infection inducing the plant host defense arsenal.

Exogenous application of hydrogen peroxide improves germination in slow drying Quercus fabri (Fagaceae) seeds, but does not improve longevity

Exogenous application of hydrogen peroxide improves germination in slow drying<i> Quercus fabri</i> (Fagaceae) seeds, but does not improve longevity

Seed priming with salicylic acid and hydrogen peroxide alleviates water deficit in wheat (Triticum aestivum L.) at seedling stage

Present experiment was undertaken during 2013–14 and 2014–15 to evaluate the effectiveness of exogenous application of hydrogen peroxide (H2O2) and salicylic acid (SA) through seed priming during water deficit on wheat seeds of two contrasting genotypes C-306 (relatively drought resistant) and HD-2329 (relatively drought susceptible). Under PEG- 6000 induced water deficit, significant differences were observed between different treatments in both the genotypes. Priming with water, SA and H2O2 improves germination rate and seedling vigour during water deficit with respect to T2(non-primed) in both the genotypes. Root length, shoot length, root dry weight, shoot dry weight and total dry weight of seedlings were also recorded to be increased significantly with respect to T2. The treatment T5 in which SA and H2O2were applied in combination, showed maximum value for the observed parameters. HD-2329 was observed to be more responsive to the priming treatments during water deficit, with respect to C-306. It may be concluded that seed priming with SA and H2O2 improves tolerance to PEG-6000 induced water deficit and they act synergistically in improving performance of seedlings of wheat.

Exogenous application of hydrogen peroxide alleviates drought stress in cucumber seedlings

Drought limits plant growth and crop yield worldwide and more frequent occurrences of water shortages are expected according to climate change projections. However, relatively little is known about whether the spraying of plants leaves with hydrogen peroxide (H2O2) would alleviate the symptoms of drought stress. In this study, 3-week-old cucumber seedlings exposed to different soil water contents (non-limiting soil water conditions, medium drought, and severe drought) were foliar-sprayed with 1.5mM H2O2. Growth, photosynthesis and oxidative defense system were determined after one week of treatment. Results showed that exogenous H2O2 significantly increased biomass, leaf relative water content (RWC) and chlorophyll content, coupled with increased net photosynthetic rate (Pn), especially under medium drought. Meanwhile, superoxide anion radicals (O2−), electrolyte leakage and malondialdehyde (MDA) levels decreased whereas the activities of key antioxidant enzymes superoxide dismutase (SOD) and peroxidase (POD) as well as soluble sugar and proline contents increased in H2O2-treated plants. Hence, exogenously applied H2O2 considerably improved drought tolerance of cucumber plants by increasing the plant antioxidative defense system and the capacity for osmotic adjustment to alleviate membrane lipid peroxidation and to reestablish cell turgor, and thereby increasing photosynthesis, particularly under medium drought.

Reactive oxygen species produced via plasma membrane NADPH oxidase regulate anthocyanin synthesis in apple peel.

Solar ultraviolet irradiation regulates anthocyanin synthesis in apple peel by modulating the production of reactive oxygen species via plasma membrane NADPH oxidase instead of other pathways. The synthesis of anthocyanin in apple peels is dependent upon solar irradiation. Using 3-mm commercial glass to attenuate solar UV-A and UV-B light, we confirmed that solar UV irradiation regulated anthocyanin synthesis in apple peels after exposing previously bagged fruit to sunlight. During sunlight exposure, UV attenuation did not affect the expression of MdHY5, MdCOP1, or MdCRY2, but significantly lowered plasma membrane NADPH oxidase activity and superoxide anion concentrations. UV attenuation also reduced the expression levels of MdMYB10, MdPAL, MdCHS, MdF3H, MdDFR, MdANS and MdUFGT1, UDP-glycose:flavonoid 3-O-glycosyltransferase (UFGT) activity, and local concentrations of anthocyanin and quercetin-3-glycoside. In contrast, exogenous application of hydrogen peroxide could enhance anthocyanin and quercetin-3-glycoside synthesis. Xanthophyll cycle pool size on a chlorophyll basis was higher but its de-epoxidation was lower under direct sunlight irradiation than that under UV-attenuating conditions. This suggests that reactive oxygen species (ROS) produced in chloroplast are not major contributors to anthocyanin synthesis regulation. Inhibition of plasma membrane NADPH oxidase activity lowered the production of ROS through this mechanism, significantly inhibited the synthesis of anthocyanin, and increased the total production of ROS in apple peel under direct sunlight irradiation, suggesting that ROS produced via plasma membrane NADPH oxidase regulates anthocyanin synthesis. In summary, solar UV irradiation regulated anthocyanin synthesis in apple peels by modulating the production of ROS via plasma membrane NADPH oxidase.

Highly Oxidized Peroxisomes Are Selectively Degraded via Autophagy in Arabidopsis

The positioning of peroxisomes in a cell is a regulated process that is closely associated with their functions. Using this feature of the peroxisomal positioning as a criterion, we identified three Arabidopsis thaliana mutants (peroxisome unusual positioning1 [peup1], peup2, and peup4) that contain aggregated peroxisomes. We found that the PEUP1, PEUP2, and PEUP4 were identical to Autophagy-related2 (ATG2), ATG18a, and ATG7, respectively, which are involved in the autophagic system. The number of peroxisomes was increased and the peroxisomal proteins were highly accumulated in the peup1 mutant, suggesting that peroxisome degradation by autophagy (pexophagy) is deficient in the peup1 mutant. These aggregated peroxisomes contained high levels of inactive catalase and were more oxidative than those of the wild type, indicating that peroxisome aggregates comprise damaged peroxisomes. In addition, peroxisome aggregation was induced in wild-type plants by exogenous application of hydrogen peroxide. The cat2 mutant also contained peroxisome aggregates. These findings demonstrate that hydrogen peroxide as a result of catalase inactivation is the inducer of peroxisome aggregation. Furthermore, an autophagosome marker, ATG8, frequently colocalized with peroxisome aggregates, indicating that peroxisomes damaged by hydrogen peroxide are selectively degraded by autophagy in the wild type. Our data provide evidence that autophagy is crucial for quality control mechanisms for peroxisomes in Arabidopsis.

Differentiation of Human Adipose-Derived Stem Cells into Fat Involves Reactive Oxygen Species and Forkhead Box O1 Mediated Upregulation of Antioxidant Enzymes

Both reactive oxygen species (ROS) and Forkhead box O (FOXO) family transcription factors are involved in the regulation of adipogenic differentiation of preadipocytes and stem cells. While FOXO has a pivotal role in maintaining cellular redox homeostasis, the interactions between ROS and FOXO during adipogenesis are not clear. Here we examined how ROS and FOXO regulate adipogenesis in human adipose-derived stem cells (hASC). The identity of isolated cells was confirmed by their surface marker expression pattern typical for human mesenchymal stem cells (positive for CD29, CD44, CD73, CD90, and CD105, negative for CD45 and CD31). Using a standard adipogenic cocktail consisting of insulin, dexamethasone, indomethacin, and 3-Isobutyl-1-methylanxthine (IDII), adipogenesis was induced in hASC, which was accompanied by ROS generation. Scavenging ROS production with N-acetyl-L-cysteine or EUK-8, a catalytic mimetic of superoxide dismutase (SOD) and catalase, inhibited IDII-induced adipogenesis. We then mimicked IDII-induced oxidative stress through a lentiviral overexpression of Nox4 and an exogenous application of hydrogen peroxide in hASC and both manipulations significantly enhanced adipogenesis without changing the adipogenic differentiation rate. These data suggest that ROS promoted lipid accumulation in hASC undergoing adipogenesis. Antioxidant enzymes, including SOD2, catalase, and glutathione peroxidase were upregulated by IDII during adipogenesis, and these effects were blunted by FOXO1 silencing, which also suppressed significantly IDII-induced adipogenesis. Our findings demonstrated a balance of ROS generation and endogenous antioxidants in cells undergoing adipogenesis. Approaches targeting ROS and/or FOXO1 in adipocytes may bring new strategies to prevent and treat obesity and metabolic syndrome.

Aclimatação ao estresse salino em plantas de arroz induzida pelo pré-tratamento com H2O2

Estudou-se o efeito da aplicação exógena de peróxido de hidrogênio (H2O2) na aclimatação ao estresse salino com base nas alterações fotossintéticas, indicadores de estresse oxidativo e atividade de enzimas antioxidativas em folhas de plantas de arroz. Utilizaram-se duas diferentes concentrações de H2O2 (1 e 10 μM) para o pré-tratamento, concentrações essas aplicadas na solução nutritiva dois dias antes da indução do estresse salino (100 μM de NaCl). A limitação fotossintética e estomática resultante da exposição ao NaCl foi amenizada quando as plantas foram pré-tratadas com 1 μM de H2O2. Plantas expostas ao pré-tratamento com H2O2 e expostas ao NaCl apresentaram dano de membrana menor quando comparadas com as plantas submetidas ao NaCl isoladamente. O conteúdo de TBARS e H2O2 foi reduzido sensivelmente nas plantas pré-tratadas com 1 μM de H2O2 e expostas ao NaCl em relação às que não foram pré-tratadas. O sistema antioxidativo enzimático nas plantas expostas ao NaCl foi induzido principalmente quando ocorreu o pré-tratamento com 1 μM de H2O2. Os dados sugerem que exposição prévia ao H2O2, pode resultar numa aclimatação mais efetiva às condições de estresse salino.

Enhanced Expression of Alternative Oxidase Genes Is Involved in the Tolerance of Rice (Oryza sativa L.) Seedlings to Drought Stress

Drought stress significantly enhanced the capacity of the alternative respiratory pathway and induced AOX1a and AOX1b transcripts in rice seedling leaves. The drought-stressed seedlings pretreated with the inhibitor of the alternative respiratory pathway, 1 mM salicylhydroxamic acid, had a lower level of relative water content than the seedlings either subjected to drought or salicylhydroxamic acid treatment alone. This observation suggests that the alternative respiratory pathway could play a role in the tolerance of rice seedlings to drought stress. Pretreatment with exogenous hydrogen peroxide, salicylic acid, and abscisic acid alone mitigated the water loss of rice leaves exposed to drought stress. Exogenous application of hydrogen peroxide and salicylic acid increased the capacity of the alternative respiratory pathway and induced AOX1a and AOX1b transcripts, while exogenous abscisic acid failed to induce any expression of AOX1 genes. These observations suggest that rice AOX1a and AOX1b genes may be responsive especially to drought stress but not be induced by all of the stress signals related to drought.

Alternative Respiratory Pathway under Drought is Partially Mediated by Hydrogen Peroxide and Contributes to Antioxidant Protection in Wheat Leaves

Water stress significantly enhanced the capacity of alternative respiratory pathway and induced AOX1 transcript in wheat (Triticum aestivum L.) leaves. The water-stressed seedlings pretreated with 1 mM salicylhydroxamic acid (SHAM) had higher level of production of reactive oxygen species (ROS) than the seedlings either subjected to drought or SHAM treatment alone did. This observation suggests that cyanide-resistant respiration could play a role in antioxidant protection under the condition of drought. Exogenous application of hydrogen peroxide effectively increased the capacity of alternative respiratory pathway and induced AOX1 transcription. Pretreatment with ROS scavengers, such as 4,5-dihydroxy-1,3-benzene disulfonic acid (Tiron) and dimethylthiourea (DMTU), arrested the increase of ROS and partly inhibited the induction of both cyanide-resistant respiration and AOX1 transcript under water stress. These results suggest that the enhancement of cyanide-resistant respiration under drought might be partially mediated by hydrogen peroxide.

Alleviation of adverse effects of drought stress on common bean (&lt;i&gt;Phaseolus vulgaris&lt;/i&gt; L.) by exogenous application of hydrogen peroxide

Effects of seed pretreatment by hydrogen peroxide (H2O2) on drought tolerance in common bean plants (Phaseolus vulgaris L.) were studied. Drought stress caused highly significant decrease in growth parameters, photosynthetic pigments, total carbohydrates and phytohormones. An increase drought stress caused highly significant increase in compatible solutes and polyamine contents as antioxidants and ABA contents in shoots of common bean plants. H2O2-pretreatment of seeds enhanced all the above parameters than the waterpretreated seeds (control) under drought condition. Results suggested that H2O2, a stress signal could trigger the activation of antioxidants in seeds which persists in the plants to alleviate the oxidative damage leading to improvements in physiological attributes for the plants growth under drought. Key words: Drought; Phaseolus vulgaris; Common bean; Advanced effect; Hydrogen peroxide DOI: http://dx.doi.org/10.3329/bjb.v40i1.8001 Bangladesh J. Bot. 40(1): 75-83, 2011 (June)