جستجوی مقالات مرتبط با کلیدواژه « آنزیم آنتی اکسیدان » در نشریات گروه « زیست شناسی »

Salinity stress is among the abiotic stresses that restrict citrus growth. In this regard, the appropriate suitable solutions to improve growth characteristics and antioxidant responses under salt stress conditions can be useful. The present pot research was conducted as a factorial experiment in a completely randomized design with three replications in the greenhouse of the University of Hormozgan during 1401. The used sour orange plants were six-month-old seedlings (height about 60 cm) that were healthy and disease-free. Experimental treatments included water salinity (1.5, 3, 4.5, and 6 dS/m) and potassium phosphite (KPhi((0, 1.5, and 3 g/l). The results revealed that the salinity of 6 dS/m compared to the salinity of 1.5 dS/m led to a decrease in leaf number, stem length and root volume (44.09, 11.4 and 37.5%, respectively) and increased ion leakage and malondialdehyde (9.23 and 41.7%, respectively). Application of potassium phosphite (KPhi( (1.5 g/l) compared to the salinity of 6 dS/m increased leaf number, stem length, root volume and root length (43.5%, 34.4%, 67.2% and 27.3%, respectively). In addition, increased protein content and activity of catalase, superoxide dismutase, phenylalanine ammonialyase, guaiacol peroxidase and ascorbic peroxidase increased (33.9, 94.4, 6.24, 22.8, 73.7 and 94.4%, respectively). Potassium phosphite (KPhi( decreased ion leakage and malondialdehyde (28.6% and 24.13%, respectively). Finally, this study showed that potassium phosphite (KPhi( (1.5 g/l) stimulates the antioxidant system, neutralizes oxygen free radicals, improves growth characteristics and moderates the harmful effects of salinity stress in sour orange seedlings.

Drought is one of the major abiotic stresses limiting plant growth and crop production. Sodium nitroprusside also plays an important role as nitric oxide releasing compound in responding to biological and abiotic stresses and controlling plant growth. The aim of study was to investigate the effect of sodium nitroprusside on reducing effects of drought stress on Satureja hortensis, which is an abundant plant used in the food and pharmaceutical industries. For this purpose, the effect of sodium nitroprusside (0, 25 and 50 μM) and different drought levels (25, 50, 75 and 100% of FC) at 2019 in greenhouse condition on growth parameters and enzymatic activity were investigated as a factorial experiment based on a completely randomized statistical design. Plants were sprayed with sodium nitroprusside in 6 to 8 leaf stage, after 24 hours, drought treatment was applied. The second stage of treatments was done one week after first stage and after two weeks, growth indices and enzymatic activity were measured. The results showed that increasing drought stress significantly decreased the fresh and dry weight of shoots and roots and chlorophyll and increased the activity of antioxidant enzymes, phenol, proline and essential oil. Simultaneous treatment of drought and sodium nitroprusside significantly increased growth parameters and activity of antioxidant enzymes by reducing drought-induced oxidative stress. The highest percentage of essential oil (1.71%) was obtained in foliar application with 50 μM sodium nitroprusside and 25% in field capacity. Finally, foliar application of sodium nitroprusside reduced the negative effects of drought stress on savory.

Foliar application of micronutrient such as zinc is a quick and easy way to eliminate or reduce the deficiency of these nutrients in plants. In order to evaluate the effects of foliar application of ordinary and nanoparticles of zinc on the growth and antioxidant responses in medicinal plant basil (Ocimum basilicum L.), this research was conducted by complete randomized design with three replicates under greenhouse conditions. The treatments were four levels zinc oxide (0, 25, 50, 100 mg.L-1) and four levels zinc oxide nanoparticles (0, 25, 50, 100 mg.L-1). Results showed that under zinc oxide treatment at 100 mg/L, the shoot and root length, and the shoot and root dry weights were significantly increased, in compare to control. The zinc nanoparticle treatment under different levels, especially at 100 mg.L-1 had a significant increase on all growth parameters including shoot and root length, inflorescence number and length, and shoot and root dry weights in comparison to control plants. By increasing concentration of both treatments (ordinary zinc and nano-zinc), the activities of antioxidant enzymes catalase, ascorbate peroxidase and guaiacol peroxidase were elevated. Minimum and maximum amounts of growth traits and antioxidant enzymes activities were observed in control and 100 mg.L-1 zinc nanoparticle, respectively. The results from this study indicate positive and obvious effect of zinc oxide nanoparticle, compared to ordinary zinc oxide, on the growth and antioxidant enzyme activity in pharmaceutical plant basil.

The present study was performed in order to use the seaweed of the Persian Gulf (brown algae Cystoseira trinodis) and also the extraction of fucoidan polysaccharide as an immunostimulant supplementation to improve and enhance some immune parameters of vannamei shrimp. Therefore, 500 shrimp with average weight of 8g were divided into four treatments in triplicate (12 tanks) in a completely randomized design and were fed with diets containing 0, 0.1, 0.2 and 0.4% of fucoidan for 30 days. Results showed a significant effect of fucoidan treatments on the measured parameters (P<0.05). The immune parameters including the number of hyaline, granular and total homocyte cells, superoxide anion, phenoloxidase, superoxide dismutase, catalase and glutathione peroxidase activities in the groups fed with diets containing different levels of fucoidan, especially 0.4% indicated a significant increase compared to the control (P<0.05), while the amount of malondialdehyde showed a significant decrease compared to the control (P<0.05). In general, according to the results of the present study, it can be stated that fucoidan extracted from brown algae Cystoseira trinodis had better performance on improve immune parameters. Therefore, this bioactive compound can be recommended as an immunostimulant in the diet of white leg shrimp.

On metal contaminated soils, ectomycorrhizal( ECM) fungi may improve plant growth through an enhanced nutrition or by alleviation toxicity of the metals. In order to evaluation of alleviating effects of ectomycorrhizal colonization on Mn toxicity, a study was performed using pistachio plants and Agaricus bisporus  fungus as factorial in a completely randomized design with three replications. The experiment included two factors: mycorrhizal (M) and non-mycorrhizal (NM) pistachio plants and five levels of the Mn concentrations (0, 200, 400, 600 and 800 μm) in 3 replicates. In this study experiment was conducted to investigate the effect of ectomycorrhizal colonization in the alleviation of oxidative stress and improvements of the antioxidant enzyme activities, lipid peroxidation and metal accumulation in pistachio trees (Fandoghi cultivar).The results showed that the increase of  Manganese concentration caused an increase in the malondialdehyde (MDA), and induction in antioxidative enzymes activity in the leaves of the M and NM plants, but it was dramatically more in M plants. A decrease of ascorbate (ASA) content was induced by increasing the zinc concentration where it was higher in M plants but all metal treatments increased dehydroascorbate (DHA) contents in both M and NM plants. The results showed that the Mn translocated from root to shoot in M plants was lower than NM plants. The amelioration of Mn toxicity by A.bisporus may be a result of improving ‌the antioxidant defense system and prevent the absorption of heavy metals.

Nanoparticles due to their unique physicochemical properties, are widely used in biotechnology. Garlic (Allium sativum) is used as spice and drug for many years. Allicin as the best known active compound of garlic has a vast variety of biological effects. In this project effect of two abiotic elicitors including silver nanoparticles (AgNPs) and silver nitrate on growth and some biochemical parameters of garlic explants were studied. On silver nitrate-exposed samples; fresh weight, allicin, protein and cysteine contents, and catalase and guaiacol peroxidase activity was less than control. On AgNPs 25 ppm, growth, allicin, protein and cysteine contents was higher than untreated explants. Allicin content of AgNPs-treated explants was greater than the other treatments, on 25 ppm silver nitrate similar to control group and in 50 ppm-treated explants was the least. In conclusion because of the medicinal effects of allicin probably AgNPs could be a good candidate to increase allicin content.

On metal contaminated soils, ectomycorrhizal( ECM) fungi may improve plant growth through an enhanced nutrition or by alleviation toxicity of the metals. In order to evaluation of alleviating effects of ectomycorrhizal colonization on zn toxicity, a study was performed using pistachio plants and Agaricus bisporus fungus as factorial in a completely randomized design with three replications. The experiment included two factors: mycorrhizal (M) and non-mycorrhizal (NM) pistachio plants and five levels of the zn concentrations (0, 30, 60, 90 and 120 μm) in 3 replicates. In this study experiment was conducted to investigate the effect of ectomycorrhizal colonization in the alleviation of oxidative stress and improvements of the antioxidant enzyme activities, lipid peroxidation and metal accumulation in pistachio trees (Badami cultivar).The results showed that the increase of zinc concentration caused an increase in the malondialdehyde (MDA), and induction in antioxidative enzymes activity in the leaves of the M and NM plants, but it was dramatically more in M plants. A decrease of ascorbate (ASA) content was induced by increasing the zinc concentration where it was higher in M plants but all metal treatments increased dehydroascorbate (DHA) contents in both M and NM plants. The results showed that the Zn translocated from root to shoot in M plants was lower than NM plants. The amelioration of Zn toxicity by A.bisporus may be a result of improving the antioxidant defense system and prevent the absorption of heavy metals.

Early sowing in spring season is important for the use of mild conditions as well as proper vegetative growth, but the occurrence of low temperatures at the beginning of the growing season may cause the problem for plant establishment. In order to investigate the effect of methyl jasmonate (MeJA) on antioxidant enzymes and improving the resistance of pumpkin (Cucurbita pepo) to low temperature stress, a factorial experiment include six concentrations of methyl jasmonate (0, 1, 5, 50, 100 and 150 μM) and three temperature levels (8, 11 and 14 °C) was conducted in a completely randomized design. The results showed that no seeds were germinated at 8 °C. At 11 °C and lack of methyl jsmonate, no seeds were germinated, but the application of methyl jasmonate increased germination to 76.66%. At 14 °C and lack of methyl jasmonate, only 26% of the seeds are germinated. However, the application of methyl jasmonate increased germination to 100%. The highest germination rate was recorded at 1 and 50 μM methyl jasmonate, which that at 14 °C. The activities of superoxide dismutase and guaiacol peroxidase were very high at both concentrations of MeJA, but at 11 ° C the highest activity of these enzymes were observed at a concentration of 1 and 100 μM of methyl jasmonate. At 14 °C, the catalase activity was higher in methyl jasmonate treatments than the control but at 11 °C it was more in the control than the methyl jasmonate treatments. Therefore, the valuable effect of methyl jasmonate to creating resistance to   relatively cool air (above 10 °C) has been proven. According to results of this experiment, it can be said that the application of methyl jasmonate increases the resistance of the seeds of pumpkin seeds to low temperature stress, and the earlier sowing of this plant can increase its production potential.

Henbane (Hyoscyamus niger) is a perennial herbaceous plant of the Solanaceae family that like to other plants of this family such as Atropa and Datura produces pharmaceutical tropane alkaloids hyoscyamine and scopolamine. These medicinal valuable compounds have anticholinergic effects, and antispasmodic and sedative properties. One of the most cost-effective strategies to increase production of active compounds in medicinal plants is the application of the biotic and abiotic elicitors. In this study, the effect of Piriformospora indica and Yarrowia lipolytica on the growth and production of tropane alkaloids and also antioxidant enzymes activity was investigated. Henbane plantlets were placed in two mediums with fungus or yeast for two weeks. The results showed that the growth and antioxidant enzymes activities were increased in plants that were treated with fungus and yeast in compare with control plantlets. Hyoscyamine content in shoot and scopolamine content in both root and shoot of the fungus treated plantlets were significantly increased in comparison to control. Also, the amount of scopolamine in roots and especially shoots of treated plants with yeast was significantly elevated in comparing with control. Therefore, P. indica and Y. lipolytica, can be used as appropriate biotic elicitors, for increasing biomass and pharmaceutical secondary metabolites in Henbane.

In order to study the effect of steroidal progesterone hormone on seedling growth, antioxidant enzyme activity, and also on callus induction from leaf explants of German Chamomile (Matricaria chamomilla L.), an experiment was conducted out based on completely randomized design with three replications using MS medium containing different concentrations of progesterone hormone (0, 0.01, 0.1, 1, and 10 mg/l) alone or with in combination of steady concenteration of 1-naphthalene acetic acid (NAA) and Benzylaminopurine (BAP). The results showed that this hormone at low concentrations (0.01 mg/l) increased seedling length, seedling and root weight and also increased peroxidase and polyphenol oxidase activity in concentrations of 0.1, 1 and 10 mg/l and at concentrations of 0.1 and 1 mg/l increased catalase activity. Although, leaf explants responded to induction of callus after one to two weeks in all media, but its growth were different depending on the presence of phytohormones and concentration of progesterone hormone. The highest callus fresh weight from leaf explants was achieved at 0.01 mg/l concentration of this hormone when used in combination with NAA and BAP phytohormones. This hormone was capable of callus induction from leaf explants when used in the absence of BAP and NAA phytohormones, but growth rate of callus was far lower than that was used in combination with BAP and NAA in the culture medium. The results of this study show that this hormone can be used in optimizing the in vitro growth conditions of plants.

This greenhouse experiment, consisted of a completely randomized factorial design, was conducted to investigate the changes in antioxidant enzyme activities of lettuce plants cv. Syahoo inoculated with Piriformospora indica fungus under different levels of zinc (0, 2.5, 5 and 10 mg l-1) in the research laboratory of Maragheh university in spring 2016. Fungal treatment was added at two leaf stage of seedling on the lettuce roots in the sandy substrate. The plant samples, at 35 days after sowing, were measured for dry and fresh weights of shoot, total soluble protein, malondialdehyde (MDA) concentration and activities of antioxidant enzymes superoxide dismutase (SOD), guaiacol peroxidase (GPOX), and catalase (CAT). The results revealed that the effect of P. indica and zinc application on dry and fresh weights of shoot, total soluble protein and activity of SOD were significant at P≤0.01. The main effect of zinc on MDA concentration, activity of GPOX and CAT was significant at P≤0.01. Highest amount of dry and fresh weights and total soluble protein, and maximum activity of SOD were obtained in presence of P. indica under 10 mg L-1 Zn. Maximum activity of CAT, GPOX, and MDA concentration were observed in treatments without zinc application. Results from our research showed that inoculation by P. indica and zinc application (especially at 10 mg L-1) have an important role in enhancing the growth parameters and modulating the activities of antioxidant enzymes in lettuce.

Cadmium (Cd) is a heavy metal that causes oxidative stress in plants. In this study toxicity effect of Cd on Silybum marianum was investigated. Four treatments of CdCl2 (0, 300, 600, 400 and 900 μM) were evaluated in five replications using complete random design. Results of tolerance stress index severity of Cd stress on plants under various levels of treatments. Shoot dry weight, leaf area, chlorophyll a content, and total chlorophyll content were significantly reduced in 900 μM of Cd. Chlorophyll b decreased in all levels of Cd stress in comparison with control. Meanwhile, Carotenoid content did not show significant change in different concentrations of cadmium. Malon De Aldehyde content, Antocyanin content, total Phenol and Flavonoid significantly increased under 900 μM cadmium concentration. Total protein content was significantly decreased in 900 μM Cd concentration while, Phenylalanine ammonia lyase, Glutathione reductase and Ascorbate peroxidases activity enzyme were significantly increased in this level. Results confirmed that this medical plant have different physiological and biochemical mechanisms to reduce toxicity damage of cadmium. Evaluation of cadmium ion concentration in leaves and root showed that most cadmium was concentrated in leaves while; small amount of Cd was in the roots. These results showed that silybum marianum could be an appropriate plant for phytoremediation purposes.

To study the effect of bacterial siderophore on the second cropping of maize (SC645) under drought stress conditions, a factorial experiment was arranged in a randomized complete block design with three replications. Two irrigation treatments (75 (I1: unstressed control) and 120 mm evaporation from Class-A pan (I2: delayed irrigation)) and two siderophore application treatments (S1: with and S2: without application) were considered as experimental factors. The foliar application of siderophore (2000 mg l-1) were applied two times at 4-6 and 12-14 leaf growth stages. In addition, 20 Kg siderophore ha-1 was applied with irrigation at jointing stage. The results showed leaf pigments, leaf relative water content (RWC), membrane stability, leaf area index(LAI) and specific leaf area (SLA) increased at I1 compared to I2, while sucrose (saccharose), lipids peroxidation (MDA), guaiacol peroxidase and polyphenol oxidase activities decreased. S1 compared to S2, showed increased leaf pigments, the ability of osmotic adjustment, antioxidant enzymes activities, RWC, membrane stability, LAI and SLA and decreased MDA. The interaction effect showed that siderophore application increase chlorophylls (a, b and total), proline and soluble sugars of leaf in each irrigation levels. The highest forage fresh yield (8697 gm-2) belonged to I1. S1 increased forage fresh yield (1644 gm-2) compared to S2. In general, bacterial siderophore can improve the morphological, physiological and biochemical capabilities of maize and is effective in mitigating the effects of drought and in increasing photosynthetic capacity.

Cadmium (Cd) is an environmentally polluting metal that has a negative effect on plant growth and yield. In this study, to understand the role of salicylic acid (SA) in alleviating cadmium toxicity in Sage (Salvia officinalis L.), the changes of biochemical and physiological indexes in Sage seedlings exposed to 0, 100, 200 or 300 ppm Cd with or without 0.1, 0.5 and 1 mM SA for 30 days was investigated. The results showed that Cd treatment reduced the growth, photosynthetic pigments, soluble sugars and activity of catalase and peroxidase enzymes, while increased proline content, phenolic compounds, MDA and H2O2. However, SA pre-treatment improved the growth and increased content of photosynthetic pigments, proline, soluble sugars and phenolic compounds at all levels of cadmium. Furthermore, SA pretreatment increased the activity of antioxidant enzymes catalase and peroxidase, and reduced MDA and H2O2, which reduced the cadmium-induced oxidative stress and, consequently, increased Sage tolerance to cadmium. According to our results, it seems SA might regulate the antioxidant defense activities, increase osmolyte and secondary metabolite compound in Cd-treated Sage, thereby improving growth and tolerance of Sage to Cd stress

This research carried out to evaluate responses of rice genotypes and cultivars to salt stress using a factorial experiment with complete block randomized design in three replications, in Dankook University, South Korea at 2012.First factor was 16 rice genotypes and cultivars at vegetable growth stage and second factor was soil salinity levels (0.8 ds m-1 as control and 6.2 ds m-2 ). Salt stress disturbed cell membrane and the highest malondealdehid obtained from Khazar, Kadus, Baekjimju byeo, Chucheomg byeo, Shimdomgjim byeo cultivars and IR29 and IR59418-7B-21-3 genotypes. The highest shoot dry weight showed in IR67075-2B-5-2 genotype (153.8 g m-2), Kochihibic (152.2 g m-2), Haraz (149.8 g m-2), Shafagh (152.0 g m-2) and Nemat (156.9 g m-2). These cultivars have maximum Kﳖ rate, antioxidant enzymes activates, relative water cotent, soluble carbohydrate and photosynthesis rate and minimum leaf Na concentration. Leaf K/Na ratio, relative water content, photosynthesis rate dry matter and malondealdehid concentration suggest for choice salt tolerance rice cultivar in vegetable stage.

In order to evaluate the allelopatic potential of Eucalyptus camaldulesis alcoholic extract on antioxidant enzyme activites, cell membrane damage and sucrose synthesis enzymes activity of Xantium strumarium, the expriments was coducted in Islamic Azad University, Shoushtar branch at 2012. The experiment was laid out according to Completely Randomized Design with four replications and treatments were various concentration of E. camaldulesis alcoholic extract (0, 4, 8, 12, 16 and gr/L). Results indicated E. camaldulesis alcoholic extract application exhibited gradual rise inhibitory effect on seedling weight, antioxidants enzymes activities and sucrose synthetesis enzymes activity but elevated the malondialdehyde concentration in Xantium strumarium seedlings. The lowest sucrose synthesis activity (2.11 nmol prot-1 min-2), seedling dry weight (2.76mg) and highest malondialdehyde concentration (0.92 nmol gr fw-1) were noted at 20 gr L-1 concentration of E. camaldulesis alcoholic extract. In conclusion, E. camaldulesis alcoholic extract decreased seedling growth, chlorophyll content, antioxidant enzymes activates and sucrose synthesis enzymes activity of X. strumarium seedling.

Astragalus fridae of family Fabaceae has farmaceutical properties، Food and dustarial value. This plant is native to the province Semnan. Aftar village located in the North West of Semnan. Its main habitat is Aftr village located northwest of Semnan. This plant is endangered of extinction. The purposes of this project included: The study of anatomical structures of aerial organs، soluble Carbohydrate content and the activity of antioxidant enzymes of plant leaves in two different times (Spring and Summer 1392). In order to survey of effect of temperature on total protein content and the activity of antioxidan enzymes (catalase، peroxidase، ascorbat peroxidase and superoxid dismutase) and soluble carbohydrate، leaves were collected in May and August. Results indicated that protein level and Soluble carbohydrate in may were less than in August، but different between means weren’t meaningful. The activity of enzymes increased in August. Results indicated that with increasing the temprature، the activity of them increased. Histological studies were stablished by using double stained of methyl green - Alumal Carmen. Petiole and leaf anatomical studies indicated that area of schloranshim in tissue samples of August were more than May which showed the plant adaptation to high temperature stress.

Water stress is one of the most important abiotic limiting factors that restricts growth, development and productivity of horticulrural crops. In vitro methods have been successfully used for evaluating water deficit stress in plants. In this regards, responses of four Iranian grapevine genotypes to drought stress induced by polyethylene glycol 6000 at -5, -5.24, -5.65, -6.24 and -7 bar were studied in Murashige and Skoog (MS) medium. Results indicated that drought stress reduced shoot fresh weight, leaf area, shoot length and leaf relative water content. Water deficit stress also caused significant increase in proline and malondialdehyde content, and activity of catalase antioxidant enzyme,. It seems that among studied genotypes, ‘Shahani’ with a greater capability to produce proline and antioxidant enzymes was more tolerant to drought stress and ‘Keshmeshi Ghermez Ghazvin’ and ‘Yaghuti Sefid’ genotypes were more susceptible and eventually ‘Asgari’genotype performed semi tolerance to water deficit stress.

Heavy metal stress in plants may cause oxidative stresses and reactive oxygen species (ROS) production. To reduce this stress, plants use antioxidative defences, such as increasing the activity of antioxidant enzymes. In this study, the role of an arbuscular mycorrhizal (AM) fungi Glomus intraradices as a symbiotic microorganism with plant, was investigated in inducing tolerance to oxidative stress induced by Nickel heavy metal. Tall fescue plants were grown in soils containing 0, 30, 90, 180 ppm of Nickel, in two forms of infected to fungi (M+) and uninfected (M-) for 3 months. Experimental results showed that Nickel treatment caused reduction in growth parameters, where these parameter were higher in M+ plants than M- ones. Membrane electrolyte leakage was increased by the increase of Nickel concentration, and the increase was higher in M+ plants compared to M- plants. Results of measuring the activity of antioxidant enzymes showed that the presence of fungi had increased the activity of catalase (CAT), guaiacol peroxidase (GPX) and glutathione reductase (GR) enzymes against the toxic effect of Nickel, but this had not affected (increasing or decreasing) the activity of ascorbate peroxidase (APX) and superoxide dismutase (SOD) enzymes. These results demonstrated the negative effect on Glutathione-S-transferase (GST) enzyme. Precense of Glomus intraradices in M+ plants amplified the antioxidant system in Festuca plants and reduced the negative effects of Nickel treatment.