Increase In Peroxide Concentration Research Articles

Functionalization of Low Density Polyethylene with Ricinol-2-oxazoline Methyl Maleate in a Twin-screw Extruder

AbstractThe grafting reaction of ricinol-2-oxazoline methyl maleate onto molten low density polyethylene was investigated in a twin-screw extruder. The influence of peroxide content, added ricinol-2-oxazoline methyl maleate and process variables such as residence time, screw speed and reaction temperature were considered. The rate and level of grafting were quantitatively measured by FTIR technique. Maximum level of grafting at constant peroxide content was obtained when concentration of ricinol-2-oxazoline methyl maleate reached 3%, above which it declined. The rate of grafting increased with increasing peroxide content. However crosslinking of polyethylene was found to have taken place as parallel competitive reaction which was intensified with increasing peroxide content. It was demonstrated that it is possible to make an optimization of the grafting reaction on the basis of experimental results. The considerable grafting yield with acceptable melt flow rate for the samples was achieved when initial ricinol-2-oxazoline methyl maleate and peroxide concentrations were 2 to 3% and 0.06 to 0.1 %, respectively.

Can species Cedrela fissilis Vell. be used in sites contaminated with toxic aluminum and cadmium metals?

Toxic metals are among the main pollutants contributing to environmental degradation. Cadmium (Cd) and aluminum (Al) stand out among these metals as extremely toxic elements. The use of native species in reforestation programs can compensate for degradation and re-establish the ecological conditions of the affected environments. Cedrela fissilis Vell., popularly known as cedar, may be used as an alternative in phytoremediation, since it is a fast-growing native woody species widely distributed in tropical America. In this study we investigated the possibility of using C. fissilis in sites contaminated with Al and Cd by evaluating morphological, physiological, and biochemical variables of seedlings grown in hydroponic system. C. fissilis seedlings were subdivided into two experiments with a completely randomized design. The first experiment evaluated the effect of four Al concentrations, namely: 0 (complete nutrient solution without phosphorus), 25, 50 and 100 mg l-1. The second experiment evaluated four Cd concentrations, namely: 0 (complete nutrient solution), 25, 50 and 100 μM. Each sample unit consisted in a pot with four plants. Morphological, physiological and biochemical variables of seedlings were evaluated after 15-day exposure to different treatments in the hydroponic system. Aluminum concentration of 100 mg l-1 caused oxidative stress in C. fissilis seedlings, reduced shoot and root dry weight, and increased hydrogen peroxide contents, which led to lipid peroxidation. Cadmium concentration of 100 µM also damaged C. fissilis seedlings by significantly reducing root dry weight and involving the most severe effects on photosynthetic variables. Cadmium presence in the nutrient solution negatively affected morphophysiological and biochemical variables of Cedrela fissilis seedlings, and it was also harmful to their growth. Based on our results, the investigated species shows a sensitive behavior upon exposure to cadmium. On the other hand, C. fissilis tolerates high Al concentrations (up to 50 mg l-1), which suggests a moderate tolerance to this metal.

Exogenous hexanoic acid induced primary defense responses in tomato (Solanum lycopersicum L.) plants infected with Alternaria solani

The effect of exogenous hexanoic acid on Alternaria solani-infected tomato plants was investigated in the present study. Tomato seedlings treated with different doses of hexanoic acid were inoculated with A. solani and their antioxidative, biochemical and molecular responses were studied. Results indicated that hexanoic acid application increased hydrogen peroxide content by 49% and peroxidase activity by 408% in the infected plants, while ascorbate peroxidase and catalase activities and total polyphenol content were not significantly changed. It was revealed that the expression of NAM, ATAF1and 2, and CUC2 family multiple stress-responsive transcription factor (SlNAC1), Mitogen-activated protein kinase 3 (SlMAPK3), increased 13 and 4 folds, respectively, while the expression increase for pathogenesis related proteins type1) (SlPR1) was 57% in A. solani-infected plants. It was also revealed that SlPR1 expression in plants treated with 1 mM hexanoic acid reached its highest level 72 h post inoculation while highest superoxide dismutase (SlSOD) expression rate was recorded 24 h after inoculation. It seems that exogenous application of hexanoic acid increased reactive oxygen species (ROS) content in A. solani-infected plants and subsequently induced systemic acquired resistance (SAR) pathways which in turn enhanced expression of superoxide dismutase (SOD), NAC1 and MAPK3 genes. These findings indicated that hexanoic acid induced resistance in tomato plants against A. solani by enhanced SAR signaling network leading to enhanced defense responses. While Ja/Et pathway is believed to be the prevalent biochemical pathway involved in plant resistance to necrotrophic pathogens, our findings revealed that hexanoic acid-treated tomato plants activated defense responses though SAR which is mainly a salicylic acid-dependent signaling pathway.

The Effect of Nitrogen Fertilization and Fusarium culmorum Inoculation on the Biomarkers of Oxidative Stress in Wheat Flag Leaves

During cultivation, wheat is exposed to several abiotic and/or biotic stress conditions that may adversely impact the wheat yield and quality. The impact of abiotic stress caused by nitrogen deficiency and biotic stress caused by phytopathogenic fungus Fusarium culmorum on biomarkers of oxidative stress in the flag leaf of nine winter wheat varieties (Ficko, U-1, Galloper, BC Mandica, BC Opsesija, Ingenio, Isengrain, Felix, and Bezostaya-1) was analyzed in this study. Hydrogen peroxide concentration and lipid peroxidation level were measured as indicators of oxidative stress, while the antioxidant response was determined by measuring the concentration of phenolic compounds and activities of antioxidant enzymes. Wheat variety and nitrogen treatment had a significant effect on all examined biomarkers of oxidative stress in the flag leaf, while the impact of Fusarium treatment was less pronounced. The most significant impact on the measured stress biomarkers had a low nitrogen level, which mainly increased hydrogen peroxide concentration and lipid peroxidation level and decreased activities of antioxidant enzymes in most varieties. The obtained results were discussed and compared with the previous study in which biochemical analyzes were performed on the wheat spike. There was no significant strong correlation between flag leaf and spike response in the measured parameters, which, in addition to the variety-specific response, also indicates a tissue-specific antioxidant response.

PRDX-1 Supports the Survival and Antitumor Activity of Primary and CAR-Modified NK Cells under Oxidative Stress.

Oxidative stress, caused by the imbalance between reactive species generation and the dysfunctional capacity of antioxidant defenses, is one of the characteristic features of cancer. Here, we quantified hydrogen peroxide in the tumor microenvironment (TME) and demonstrated that hydrogen peroxide concentrations are elevated in tumor interstitial fluid isolated from murine breast cancers in vivo, when compared with blood or normal subcutaneous fluid. Therefore, we investigated the effects of increased hydrogen peroxide concentration on immune cell functions. NK cells were more susceptible to hydrogen peroxide than T cells or B cells, and by comparing T, B, and NK cells' sensitivities to redox stress and their antioxidant capacities, we identified peroxiredoxin-1 (PRDX1) as a lacking element of NK cells' antioxidative defense. We observed that priming with IL15 protected NK cells' functions in the presence of high hydrogen peroxide and simultaneously upregulated PRDX1 expression. However, the effect of IL15 on PRDX1 expression was transient and strictly dependent on the presence of the cytokine. Therefore, we genetically modified NK cells to stably overexpress PRDX1, which led to increased survival and NK cell activity in redox stress conditions. Finally, we generated PD-L1-CAR NK cells overexpressing PRDX1 that displayed potent antitumor activity against breast cancer cells under oxidative stress. These results demonstrate that hydrogen peroxide, at concentrations detected in the TME, suppresses NK cell function and that genetic modification strategies can improve CAR NK cells' resistance and potency against solid tumors.

Is hydrogen peroxide generated in wine?

Wines contain significant amounts of polyphenols which autoxidize upon contact with oxygen, producing hydrogen peroxide. We checked more than 40 samples of white and red wines finding, on average, production of small amounts of hydrogen peroxide within 3 h after the wines had contacted with air, though some samples did not produce detectable amounts of H2O2. The increase in hydrogen peroxide concentration after 3-h incubation of wines after opening ranged from −3.09 to 6.60 μM. Wines showed also the ability of hydrogen peroxide scavenging, which can be partly attributed to sulfite. Thus, the measured net production of hydrogen peroxide in wine is a result of the actual production and scavenging of hydrogen peroxide.

The Effect of Dialkyl Peroxide Crosslinking on the Properties of LLDPE and UHMWPE.

Peroxide has been considered a chemical agent that can be used to tune the properties of polymeric materials. This research evaluated the influence of different concentrations of dialkyl peroxides on the mechanical, thermal, and morphological properties of linear low-density polyethylene (LLDPE) and ultra-high molecular weight polyethylene (UHMWPE). The neat polymer, as well as those with the addition of 1% and 2% by mass of dialkyl peroxides, were subjected to compression molding and immersion in water for 1 h, under controlled temperatures of 90 °C. The values of the gel content found in the samples indicated that the addition of peroxide to the LLDPE and to the UHMWPE promoted the formation of a reticulated network. The structure obtained by the crosslinking led to less reorganization of the chains during the crystallization process, resulting in the formation of imperfect crystals and, consequently, in the reduction in melting temperatures, crystallization and enthalpy. The mechanical properties were altered with the presence of the crosslinker. The polymers presented had predominant characteristics of a ductile material, with the occurrence of crazing with an increased peroxide content.

Plasmonic Imaging of Electrochemical Reactions at Individual Prussian Blue Nanoparticles.

Prussian blue is an iron-cyanide-based pigment steadily becoming a widely used electrochemical sensor in detecting hydrogen peroxide at low concentration levels. Prussian blue nanoparticles (PBNPs) have been extensively studied using traditional ensemble methods, which only provide averaged information. Investigating PBNPs at a single entity level is paramount for correlating the electrochemical activities to particle structures and will shed light on the major factors governing the catalyst activity of these nanoparticles. Here we report on using plasmonic electrochemical microscopy (PEM) to study the electrochemistry of PBNPs at the individual nanoparticle level. First, two types of PBNPs were synthesized; type I synthesized with double precursors method and type II synthesized with polyvinylpyrrolidone (PVP) assisted single precursor method. Second, both PBNPs types were compared on their electrochemical reduction to form Prussian white, and the effect from the different particle structures was investigated. Type I PBNPs provided better PEM sensitivity and were used to study the catalytic reduction of hydrogen peroxide. Progressively decreasing plasmonic signals with respect to increasing hydrogen peroxide concentration were observed, demonstrating the capability of sensing hydrogen peroxide at a single nanoparticle level utilizing this optical imaging technique.

A novel simple fluorescent probe for the detection of hydrogen peroxide in vivo with high selectivity

Hydrogen peroxide (H2O2) plays an important role in the initiation and progression of many diseases. Therefore, the detection of H2O2 in vivo is very important to elucidate its biological functions in various diseases. At present, the research of fluorescent probes has attracted wide attention. Fluorescent probes are becoming more and more useful as tools for detecting various substances. In this paper, we present a novel fluorescent probe capable of selectively detecting H2O2 in organisms. This probe is based on the design strategy of the recognition of H2O2 enhancing the water-solubility, as a result, producing the turn-on fluorescence intensity. With the increase of hydrogen peroxide concentration, the fluorescence intensity of the newly as-prepared probe is enhanced. There was a good linear relationship when the concentration range of hydrogen peroxide was from 1 μM to 100 μM. In terms of cell imaging work, the detection of endogenous and exogenous H2O2 in RAW 264.7 macrophage cells showed obvious fluorescence enhancement under confocal microscopy. So this new probe has been shown to be a reliable chemical tool for detecting the generation and development of H2O2-related diseases in living systems.

Chitosan-modified biochar immobilised arsenic in root medium and enhanced the growth of zucchini (cv. Courgette d’Italie) seedlings

Contamination of arsenic (As) presents a health hazard that affects home gardeners neighbouring contaminated environments. The use of chitosan-modified biochar was investigated to immobilise As(V) from aqueous solution and zucchini seedlings (cv. Courgette d’Italie) were grown as a test crop. The results of characterisation revealed that the presence of chitosan on biochar (BR) surface improved its efficiency of As(V) immobilisation from the contaminated environment. A sorption study further showed that compared with the BR, (BR-C) chitosan-modified biochar (0.1 g) depicted the increased immobilisation of As(V) (10 ppm) from solution. Both Langmuir and Freundlich models fitted well, showing monolayer as well as multilayer sorption. BR-C showed a high Langmuir arsenic sorption capacity of 57.83 mg/g, which effectively decreased the level of As(V) toxicity. As demonstrated in results, As-stress reduced plant growth, seedling length, photosynthetic pigments, soluble sugar, increased hydrogen peroxide contents, and electrolyte leakage percentage. Simultaneously, BR and BR-C were effective against As(V) stress-induced changes in the zucchini plant. Collectively, the results of this study indicate that the modification of BR with chitosan can efficiently immobilised arsenic in the root medium and enhance growth of zucchini under controlled conditions by reducing the uptake of As(V).

Inactivation of Escherichia coli O157:H7 and Salmonella Typhimurium in black and red pepper by vacuumed hydrogen peroxide vapour.

In this study, the efficacy of using vacuumed hydrogen peroxide vapour (VHPV) to inactivate foodborne pathogens in whole dried black pepper (Piper nigrum) and powdered dried red pepper (Capsicum annuum) was evaluated. Black and red pepper inoculated with Escherichia coli O157:H7 and Salmonella Typhimurium were subjected to 3.81, 7.93, 12.33, 17.04 and 21.67mgl-1 VHPV for 1min, and the change in pepper colour was evaluated after treatment. Pathogen quantities decreased with increasing hydrogen peroxide concentration. For black pepper, the 21.67mgl-1 VHPV treatment decreased E. coli O157:H7 and S. Typhimurium quantities by >6.12 and 4.52log CFU per gram, respectively, without causing colour change. In addition, the 21.67mgl-1 VHPV treatment caused 4.35 and 2.36log CFU per gram reductions in these two pathogen quantities in red pepper, respectively. During the VHPV treatment, colour values of peppers did not significantly change. VHPV effectively reduced the levels of foodborne pathogens in black and red pepper while inducing minimal colour changes. Hydrogen peroxide vapour (HPV) is typically used as a sterilization method for medical devices, and many studies have confirmed the effectiveness of HPV or the gaseous phase of hydrogen peroxide on the inactivation of micro-organisms. However, using HPV for food pasteurization has rarely been studied. In the present study, we confirmed that VHPV effectively reduced the levels of pathogens in black and red pepper without colour changes.

Leaching of vanadium, potassium, and iron from spent catalyst of the manufacture of sulfuric acid

The sulfuric acid industry produces large volumes of spent catalyst containing vanadium. To develop an efficient method for vanadium recovery, hydrogen peroxide was used to oxidize sulfur in the spent catalyst, forming sulfuric acid, which, in turn, leached the metals from the catalyst. Experimental results showed that the leaching efficiency of vanadium gradually increased with hydrogen peroxide concentration; other parameters had minor effects. The hydrogen peroxide concentration, stirring rate, and pH had negative effects on leaching percent of potassium. Leaching efficiency of iron decreased with an increase in leaching time, stirring rate, and pH; with the increase in hydrogen peroxide concentration and liquid:solid ratio, leaching efficiency of iron first increased and then decreased. The optimum leaching conditions for vanadium were hydrogen peroxide concentration of 148 g/L, leaching time of 5 min, leaching temperature of 25 °C, stirring rate of 300 r/m, and liquid:solid ratio of 3:1, and leaching efficiencies of vanadium, potassium, and iron were 92.2%, 48.2%, and 46.3%, respectively. For potassium and iron, the leaching efficiencies of 70.9% and 70.5% were achieved using pure water leaching under the conditions of leaching time of 30 min, liquid to solid ratio of 4:1, and the temperature of 25 °C.

INFLUENCE OF PLASMA-ELECTROLYTIC OXIDATION PROCESS TECHNOLOGICAL PARAMETERS OF ALUMINUM ON COATING GROWTH RATE

There has been carried out an analysis of methods of oxide covering formation productivity increasing during plasma electrolytic oxidation of aluminum in electrolyte. There has been developed a technology of blank manufacturing and part strengthening by plasma electrolytic oxidation in the electrolyte, as well as the workbench has been modernized. There has been studied the process of oxidoceramic coating synthesis for the D16T aluminum deformed alloy of during plasma electrolytic oxidation in the electrolyte for different process parameters. It is established that the growth rate of oxidoceramic coating can be significantly increased by electrolyte component concentration involved in aluminum oxidation and rational choice of process electrical parameters. Hydrogen peroxide addition leads to obtained oxoceramic coating thickness increasing due to O, O2, OH, OH– concentration increasing in the electrolyte. It is established that the optimal concentration of H2O2 ranges from 5 g/l to 7 g/l. A further increase of peroxide concentration leads to a decrease in peroxide effect on oxoceramic coating growth rate on the D16T aluminum deformed alloy due to pH changes of the electrolyte and the deterioration of the oxide coating.

Selenium-Alleviated Testicular Toxicity by Modulating Inflammation, Heat Shock Response, and Autophagy Under Oxidative Stress in Lead-Treated Chickens.

Lead (Pb), a toxic pollutant, is toxic to the testis. However, biological events during testicular Pb poisoning were not well understood. Selenium (Se) has the ability to antagonize Pb toxicity. The purpose of this research was to clarify the relief mechanism of Se on testicular toxicity of Pb from the perspective of oxidative stress, inflammation, heat shock response, and autophagy in a chicken model. Sixty male Hyline chickens (7-day-old) were randomly assigned into four groups. The feeding program consisted of a commercial diet, a Se-supplemented diet (1mgkg-1 Se), a Pb-supplemented diet (350mgL-1 Pb), and a Se- and Pb-supplemented diet, respectively. On the 12th week, serums were collected to measure testosterone level and testes were removed to determine testis weight, histological structure, Pb and Se concentrations, oxidative stress indicators, and mRNA and protein expression of inflammatory cytokines, heat shock proteins, and autophagy-related genes. The results showed that Pb poisoning changed the histological structure of testes; decreased serum testosterone level, testis weight, catalase, glutathione-s-transferase, and total antioxidative capacity activities; increased hydrogen peroxide content; inhibited interleukin (IL)-2 and mammalian target of rapamycin expression; and promoted IL-4, IL-12β, heat shock proteins, Beclin 1, Dynein, autophagy-related proteins 5, light chain 3 (LC3)-I, and LC3-II expression in the testes of chickens. Se intervention mitigated the aforementioned alterations induced by Pb. In conclusion, Pb led to oxidative stress, which triggered inflammation, heat shock response, and autophagy. Se administration mitigated testicular toxicity of Pb mainly by mitigating oxidative stress in male chickens.

Peroxidase activity of hemoglobin and heme destruction in the presence of hydrogen peroxide and CT-DNA

The aim of this study was to investigate the peroxidase activity of Hb with different concentrations of hydrogen peroxide and compare it with hypochlorous acid effect on Hb. Hypochlorous acid at higher concentrations decomposed Hb and heme, releasing fee iron ion from the metal center. High concentrations of hydrogen peroxide switched the peroxidase activity of Hb towards the partial Hb and heme destruction. Heme alone was degraded showing that the Hb conformation and protein environment protects Hb from the distraction in the presence of highly increased hydrogen peroxide concentration that occurs as a result of oxidative stress. In the presence of CT-DNA acted inhibition of the peroxidase activity of Hb was observed signaling inhibited hydrogen peroxide consumption.

Stimulatory effect of exposure to low-power-density 2.45 GHz microwaves on Arabidopsis thaliana seedlings in vitro

Communication technologies are moving toward higher microwave frequencies and bandwidths to satisfy the growing demand for high data rates. The concern about the possible effects of microwaves on plants and animals has increased recently. There is still uncertainty concerning the effects of microwaves on plants. The present study was conducted to investigate the effect of industrial, scientific and medical (ISM) radio band microwaves on seedlings and seeds of Arabidopsis thaliana (L.). In vitro growing A. thaliana wild-type seedlings and seeds were exposed to 2.45 GHz continuous-wave microwaves at a power flux density of 1.0 ± 0.1 W m−2 for 48 h. Microwave exposure increased the hydrogen peroxide content, photosynthetic pigments, nonphotochemical quenching and fluorescence of the seedlings, while peroxidase activity and Fv/Fm values were unchanged. Anthocyanin and malondialdehyde were decreased. Seed germination rate, fresh weight and photosynthetic pigment contents of 10-day-old seedlings obtained from microwaves exposed seeds remained unchanged. Results confirmed the inexistence of oxidative stress but a stimulatory effect of microwave on A. thaliana seedlings. The increased hydrogen peroxide content and nonphotochemical quenching suggest acceptance of extra photon energy and a portion of the excess captured photon passing through the photosystem, while a portion of energy dissipated as heat.

“CRITICAL EVALUATIION OF EFFIICACY, REBOUND EFFECT AND SENSIITIIVIITY OF IN--OFFIICE VS AT--HOME BLEACHIING TECHNIIQUES: AN IN VIIVO STUDY”

Materials and method: 20 patients were selected. All patients were enrolled in split arch study design in which first quadrant bleaching was done by in-office bleaching technique and second quadrant bleaching was done by at-home bleaching technique using Polaoffice and Polanight bleaching products By SDI. Shade selection was done using 3D-MASTER within the standardized light. The shades were visually assessed by two expert examiners independently with reference to value ordered shade guide. The tooth sensitivity of patient in both first and second quadrant was evaluated using visual analog scale. At-home bleaching was done for 45 minutes on first day, third day and fifth day. On fifth day in-office bleaching was done for eight minutes of 3 cycles. Result In office bleaching technique performed with respect to tooth whitening, color regression and sensitivity. Conclusion: The bleaching efficacy, longevity can be improved with increased hydrogen peroxide concentration in certain amount but with minimum application of time. The newer product with neutral pH enhances the bleaching efficacy but also helps in reducing the sensitivity and relapse. The effectiveness and risk of sensitivity after the tooth bleaching depends on the techniques.

Chemical modification of poly(1‐butene) resins through reactive processing

AbstractControlled‐rheology poly(1‐butene) resins have been produced by chemical modification of commodity poly(1‐butene) (PB‐1) resins through reactive processing with an organic peroxide. Using various amounts of peroxide, samples have been produced and have been analyzed in terms of their molecular and rheological properties. Molecular weight distributions (MWD) as determined by gel permeation chromatography (GPC) indicate that polydispersity (PDI) remains approximately constant but weight‐average molecular weight (Mw) decreases with increasing peroxide concentration. These trends are in agreement with predictions from a kinetic model previously developed for the production of controlled‐rheology polypropylene. Linear viscoelastic measurements indicate that the modified samples are thermorheologically simple and that zero‐shear viscosity decreases with increasing peroxide concentration while flow activation energy remains approximately constant. Finally, no significant variation in melting and crystallization properties was observed for the range of peroxide concentrations used. Based on these results, it is proposed that tailor‐made controlled‐rheology poly(1‐butene) resins can be produced easily through reactive extrusion operations similar to those used for the production of controlled‐rheology polypropylene (CRPP).

Tolerance responses in wheat landrace Bolani are related to enhanced metabolic adjustments under drought stress

Physio-biochemical adaptations of wheat landraces may have great importance in their growth, survival and yield under drought stress. Here, we evaluated the effects of drought stress on some defense systems of wheat cultivar “Sistan” (drought-sensitive) and landrace “Bolani” (drought-tolerant). Under drought stress, Bolani plants showed lower increases in hydrogen peroxide content compared to Sistan ones, which was accompanied with significant decrease in malondialdehyde and electrolyte leakage indices. Increasing the transcript levels and activity of enzymatic and non-enzymatic antioxidants along with phenylpropanoid metabolites improved relative tolerance to drought-induced oxidative stress, particularly in Bolani plants, results which may be confirmed by a significant decrease in the damage indices. In the phenylpropanoid pathway, the biosynthetic pathway of total phenol, flavonoids and anthocyanins was more active than lignin-biosynthetic pathway, which could early respond to drought stress. These results may be confirmed by their negative significant correlations with damage indices as well as a non-significant correlation of lignin with most enzymatic and non-enzymatic antioxidants in plants. Lower decrease of chlorophyll (Chl) and carotenoid contents in Bolani plants compared to Sistan ones indicated the relative stability of photosynthetic pigments under drought stress. Our results suggested that integrating metabolic pathways could coordinately alleviate oxidative stress that can lead to introducing suitable genetic sources for drought tolerance.

Antioxidative responses to short-term salinity stress induce drought tolerance in walnut

This experiment was to evaluate the possibility of rapid induction of drought tolerance in greenhouse grown Juglans regia 'Chandler' by imposing a controlled salt stress. The plants were preconditioned by controlled salt stress (100 mM of Na2SO4, CaCl2 or KNO3, 50 mM of Na2SO4+CaCl2, 50 mM of Na2SO4+KNO3, 50 mM of CaCl2+KNO3, and 30 mM of each salt in half strength Hoagland’s nutrient solution). After 9 days, investigation of physiological and biochemical responses of the plants indicated that the halopriming treatments increased hydrogen peroxide concentration in the leaves which resulted in accumulation of phenolics and anthocyanins, and enhanced activity of ascorbate peroxidase in the leaves. Increase in catalase activity was observed which was associated to protein accumulation in the leaves. Investigating leaf greenness, concentrations of chlorophylls, and CO2 assimilation rate indicated that the halopriming treatments had no adverse effects on the plants' health and performance. The plants' drought tolerance was evaluated by withholding irrigation for 30 days. After the drought period, concentrations of hydrogen peroxide and malondialdehyde, and plasma membrane injury index in leaves of the preconditioned plants were lower than those in the non-preconditioned plants. Lower oxidative damage and higher chlorophylls' concentration and CO2 assimilation rate in the preconditioned plants were observed, which were related to enhancement in catalase and ascorbate peroxidase activity and higher concentrations of phenolics and anthocyanins in their leaves. The best results in inducing drought was obtained by halopriming with Na2SO4 or Na2SO4+KNO3. Controlled salt stress as a rapid, environmentally friendly and inexpensive approach for inducing drought tolerance in greenhouse grown walnut 'Chandler' was suggested.