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In this study, water stress was applied by polyethylene glycol at a concentration of 20 perecentage. To improve the resistance of the plants, the samples were treated by potassium nitrate at concentrations 5, 10, and 15 mM within 9 days. Changes in proline, total protein, photosynthetic pigments, carotene, anthocyanin, malondialdehyde, phenols, flavonols, flavonoids, soluble sugars and potassium ion were examined. The results showed that tobacco plants which had been exposed to drought used the accumulation of osmolytes such as proline, soluble sugars and potassium in order to balance their osmotic pressure. Drought stress also caused oxidative stress and increased the production of active forms of oxygen. As a result, non-enzymatic antioxidant defense system of tobacco plants including anthocyanins, flavonoids, flavonols and beta-carotene increased, which could be considered to be a major step for resistance to drought. The results also showed that the concentration of 15 mM potassium nitrate in particular, could significantly improve some of the harmful effects of stress and reduced photosynthetic pigments and proteins. Potassium nitrate could also bring down the MDA and beta-carotene levels to equivalent levels in control plants. As a result, it seems that using potassium can affect plant resistance to drought and plays an important role to reduce some harmful effects of stress.

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This study aimed to investigate the protective effect of Arctium lappa (AL) on gentamicin (GM)-induced nephrotoxicity in rats. Twenty-four Wistar rats were divided into four groups including: control group; GM group (intrapritoneal injection, IP, of 100 mg/kg GM B.W.); GM+AL group (received IP injection of 100 mg/kg GM and 500 mg/kg AL orally) and AL group (received 500 mg/kg AL orally). The experimental period lasted for 10 days. Nephrotoxicity was biochemically and histologically evaluated. The concentrations of creatinine, urea, malondialdehyde (MDA), superoxide dismutase (SOD) and peroxide hydrogen (H₂O₂) in the serum samples were determined. Moreover, histological examinations were performed. The animals treated with gentamicin showed significantly higher serum urea, creatinine, MDA and H₂O₂ levels and lower SOD activity. However, co-administration of AL produced amelioration in biochemical indices of nephrotoxicity in serum. Histomorphological examination showed necrosis and desquamation of tubular epithelial cells in the renal cortex in animals treated with gentamicin whereas simultaneous administration of AL and GM reduced histological damages. The data obtained suggest that treatment with AL extract can help to reduce gentamicin-induced nephrotoxicity.
 
 
 

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In patients with cerebral ischemia, both during hospitalization and in the community, the prevalence of major depression is evident. Since the depression has a negative impact on recovery, its timely diagnosis and treatment is essential. This study aimed to evaluate the effect of the oral administration of Chevilan extract (Ferulago angulata hydroalcoholic extract; 100, 200 and 400 mg/kg) on brain oxidative stress indices and depression after permanent bilateral common carotid artery occlusion or ischemia/hypoperfusion in male adult rats. A number of 35 rats were divided into a control group, an ischemic group and ischemic groups receiving doses of 100, 200 and 400 mg/kg of Chevilan extracts for 14 days by gavage. To make animal models of permanent cerebral hypo perfusion/ischemia, right common carotid artery was ligatured first and the left one ligatured with an interval of one week. To evaluate depression, immobility in the forced swimming time of each rat was measured and then the rat’s brain tissues were extracted to separate hippocampus and measure malondialdehyde. The results showed that ischemia/hypoperfusion increased brain oxidants such as lipid per oxidation (LPO) and immobility. Also, ischemic rats treated with all three doses of the Chevilan show significant reduction in the concentration of MDA hippocampus and in immobility time at a dose of 100 mg/kg and 200 / 400mg, respectively. Increased swimming time was observed in all three groups of extract recipients. It was found that Chevilan extract with antioxidant effect can reduce the side effects of ischemia such as depression.
 

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One of the major abiotic stresses that negatively affects plants is the presence of heavy metals. Soil pollution with heavy metals, resulting from the industrial development and use of fertilizers containing heavy metals, has become a major environmental concern in human societies. Mercury is a toxic heavy metal that causes pollution in agricultural lands. Accumulation of Hg by plants may disrupt many cellular functions and block growth and development. Under such conditions, the enzymatic and non-enzymatic defense systems of plants are activated. Several defense systems are cooperating together in plants to cope with stressful situations. In this study, the effect of different concentrations of mercury on the photosynthetic pigments content and non-enzymatic defence systems in Nicotiana tabacum was studied. After planting the plants under the same conditions in the hydroponic medium and feeding the plants with Hoagland solution, treatments with different concentrations of mercury nitrate (0.5, 1 and 3 mM and a control group) were applied to the seedlings in three replications. Ten days after the application of the treatments, the plants were harvested and examined. The results showed that tobacco plants which had been exposed to heavy metal used the accumulation of osmolytes such as proline and soluble sugars in order to balance their osmotic pressure. The decrease in the amounts of photosynthetic pigments and increase in the levels of malondialdehyde in the leaves indicated the elevation of oxidative damage. Increased activity of non-enzymatic antioxidants in tobacco leaves, including anthocyanins, phenol, flavonols and flavonoids, can be interpreted as the mechanisms of resistance to heavy metal stress induced by mercury.
 

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Selenium, a non-essential element for plants, is essential for animals as well as human beings. Although the role of selenium in plants is yet to be properly understood, previous researches have shown that this element can affect plant growth and metabolism. In this study, the effect of foliar application of selenium nanoparticles (0, 5, 10, and 20 mg/L) and sodium selenate (0, 5, 10, and 20 mg/L) on the physiological and biochemical responses of bell pepper (Capsicum anumm L.) was investigated. The potential changes in various growth and biochemical indices were evaluated in response to the treatments. According to the results, selenium treatments at concentrations of 10 and 20 mg/L reduced the biomass accumulation in both roots and shoots. These treatments also increased the content of hydrogen peroxide and malondialdehyde. The foliar application of selenium led to the increase of the concentrations of soluble phenols, proline and thiols. The activity of antioxidant enzymes including catalase, peroxidase, ascorbate peroxidase, and polyphenol oxidase were increased in response to the selenium treatments. The protease activity displayed a similar upward trend following the selenium treatments.

 

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Rana Valizadeh Kamran¹, Lamia Vojodi Mehrabani², Ali Aryan¹ & Alireza Tarinejad^1
1
Corresponding author: Rana Valizadeh Kamran, rana.valizadeh@gmail.com

Abstract. Bioremediation is a promising strategy to reduce the concentration of heavy metals that their increase in the soil was the result of the development of industries and factories in the area, threatening the environment and human health. To investigate the effect of the heavy metal chromium and the reduction of its toxic effects by bacteria (at two levels of the absence of bacteria and the presence of bacteria in Hoagland's solution), a factorial experiment was conducted as a completely randomized design with three replications and the morphological, physiological traits and plant elements were measured in the applied treatments. The results showed that the experimental treatments did not affect plant yield traits, fresh weight, stem length, and leaf length. Leaf width, chlorophyll a, b, and plant phosphorus content decreased under chromium stress and increased with bacterial treatment. Hydrogen peroxide, malondialdehyde, ascorbate peroxidase, superoxide dismutase, catalase, proline, solid soluble substances, phenol, flavonoid, and anthocyanin, as well as the content of plant elements such as chromium, nitrogen, and potassium, increased due to the chromium treatment. Using bacteria in the culture medium containing chromium, significantly decreased the hydrogen peroxide and malondialdehyde, indicating a reduction in the oxidative stress. The non-enzymatic and enzymatic antioxidants of plats in the bacterial treatments increased, indicating bacteria's role in strengthening the plant's antioxidant system. The chromium content of the plant decreased after the use of bacteria. The results showed the positive effect of using chromium-purifying bacteria in the environment of plant cultivation in reducing the harmful effects of chromium heavy metal stress.