Metalloid arsenic is considered as one of the most important environmental contaminant compounds.... more Metalloid arsenic is considered as one of the most important environmental contaminant compounds. Some plants with high concentrations of arsenic accumulation in their shoots, have the ability to purify arsenic-contaminated areas. Due to the chemical similarity between arsenate and phosphate, similar behavior has been observed by plant uptake system. In this study, hydroponic experiment was conducted of Isatis cappadocica, a newly-discovered As hyperaccumulator. Accordingly, we conducted this experiment to compare the interaction of arsenic and phosphorus on antioxidant compounds of I. cappadocica. Therefore, the plants were grown for 6 weeks in a medium, embedded with combinations of 50, 200, 800 & 1200 μmol l−1 arsenic and 5, 50, 200, 800 & 1600 μmol l−1 phosphorus, respectively. The dry weight, hydrogen peroxide, antioxidant compounds and the arsenic and phosphorus concentration of harvestable parts were determined. The highest concentration of arsenic was obtained in plants trea...
International Journal of Phytoremediation, Jan 21, 2021
NADPH-dependent superoxide production by intact human neutrophils is inhibited by DPI (diphenylen... more NADPH-dependent superoxide production by intact human neutrophils is inhibited by DPI (diphenyleneiodonium), when stimulated by either FMLP (N-formylmethionyl-leucyl-phenylalanine) or PMA (phorbol 12-myristate 13-acetate). Addition of 10 ,#M-DPI abolished the reduction of both the FAD and the cytochrome b components of the NADPH oxidase. DPI inhibition of the oxidase was associated with defective aerobic killing of staphylococci by human neutrophils. Anaerobic killing, phagocytosis, chemotaxis and motility were relatively unaffected by 10,uM-DPI. Degranulation of the azurophil and specific granules, induced by the soluble stimuli FMLP or PMA, and by particulate stimuli was decreased by the presence of DPI. The above effects of DPI on human neutrophils are similar to those found in chronic granulomatous disease. Bactericidal assays The Oxford strain of Staphylococcus aureus (N.C.T.C. 6571) was used in bactericidal assays. Bacteria were prepared and bactericidal assays performed as described by Williams et al. (1985), with human in place of bovine neutrophils. Lysostaphin was used to remove extracellular staphylococci in the determination of intracellular survival (Tan et al., 1971). Neutrophils (3.3 x 106/ml) and bacteria (106/ml) were suspended in 20 mM-phosphate-buffered saline (0.137 M-NaCl/2.68 mM-KCI/8. 1 mM-Na2HPO4/ 1.47 mM-KH2PO4, pH 7.0) containing 1.26 mM-CaCl2, 0.41 mM-Vol.
Environmental Science and Pollution Research, May 26, 2019
A hydroponic experiment was conducted to explore the interactive effects of selenium (Se) supplem... more A hydroponic experiment was conducted to explore the interactive effects of selenium (Se) supplementation (0, 5, and 10 μM) and arsenic (As) toxicity (0, 200, and 400 μM) on the growth, accumulation, and oxidative damage along with defense mechanisms of metallicolous (MP) and non-metallicolous population (NMP) of Isatis cappadocica, an As-hyperaccumulator, and Brassica oleracea as reference brassica. The results revealed that As stress significantly hampered plant growth particularly in B. oleracea. It reduced plant growth due to enhanced oxidative load of As-stressed plants. Between the two Isatis populations, metallicolous plants accumulated significantly higher As, however with considerably low growth defects. Furthermore, Se supplementation counteracted the adverse effects of stress on growth and physiological performance of all studied plants. Addition of Se, particularly at higher dose (10 μM), significantly suppressed root As uptake and slightly its accumulation in shoots of B. oleracea plants treated with 400 μM As, and thus improved growth characteristics of stressed plants. Under As stress, Se supplementation increased the activities of enzymatic (peroxidase (POD) and glutathione reductase (GR)) and nonenzymatic (anthocyanins and total flavonoids) antioxidants, thereby suggesting relieved As stress by reduced oxidative damage. Taken together, these results support the beneficial role of Se in the regulation of As stress by improving growth, physiology, and antioxidant capacity, and highlight its significance for plants grown on such metal-contaminated soils.
Arsenic (As) and cadmium (Cd) belong to the group of major pollutants extremely toxic to plants. ... more Arsenic (As) and cadmium (Cd) belong to the group of major pollutants extremely toxic to plants. Metal hyperaccumulating plants play an important role in phytoextraction of heavy metals. Silicon (Si) plays an important role in the amelioration of heavy metal stress through physio-biochemical mechanisms, which remain poorly understood in hyperaccumulators. The main purpose of this study was to determine the impact of Si on growth and performance of As hyperaccumulator Isatis cappadocica Desv., exposed to As and Cd. Results showed that Si (especially at 1 mM level) alleviated the harmful impact of As/Cd and significantly increased the root and shoot biomass, root and shoot length and chlorophyll contents of I. cappadocica by enhancing the plant defense mechanisms. Between the two investigated harmful elements, As was accumulated in plant parts significantly more than Cd, however with considerably lower toxic growth effects. The As/Cd concentration, bioaccumulation and translocation factor and total As content both in roots and shoots of Si-supplied plant were significantly reduced as a protective mechanism, especially in Cd exposed plant. In comparison with single As/Cd treatment, Si supply reduced H2O2 content, increased total soluble protein content and enhanced glutathione S-transferase activity in shoots. The results of this study clearly showed that Si minimized As/Cd uptake and root to shoot translocation, and therefore Si cannot enhance the phytoextraction potential of this plant species. Additionally, Si-improved growth and reduced oxidative damages caused by excess of As and Cd suggested that the similar mechanisms of metal(loid) alleviation are adopted in hyperaccumulators as well as non-hyperaccumulating plants.
Arsenic (As) is a toxic metalloid that severely hampers plant growth and also poses health risks ... more Arsenic (As) is a toxic metalloid that severely hampers plant growth and also poses health risks for humans through the food chain. Although nitric oxide (NO) is known to improve plant resistance to multiple stresses including metal toxicity, little is known about its role in the As tolerance of hyperaccumulator plants. This study investigates the role of the exogenously applied NO donor, sodium nitroprusside (SNP), in improving the As tolerance of Isatis cappadocica, which have been reported to hyperaccumulate As. Exposure to toxic As concentrations significantly increases NO production and causes damage to the cell membrane, as indicated by increased hydrogen peroxide (H2O2) and malondialdehyde (MDA) concentration, thereby reducing plant growth. However, the addition of SNP improves growth and alleviates As-induced oxidative stress by enhancing the activity of superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR), glutathione S-transferase (GST), glutathione (GSH), as well as proline and thiol concentration, thereby confirming the beneficial role played by NO in enhancing As stress tolerance. Furthermore, the As-induced decrease in growth and the increase in oxidative stress were more marked in the presence of bovine hemoglobin (Hb; a NO scavenger) and N(G)-nitro-L-arginine methyl ester (L-NAME; a NO synthase inhibitor), thus demonstrating the protective role of NO against As toxicity. The reduction in NO concentration by L-NAME suggests that NOS-like activity is involved in the generation of NO in response to As in I. cappadocica.
Arsenic (As) is a toxic metalloid dispersed in the environment and it cause serious toxicity to p... more Arsenic (As) is a toxic metalloid dispersed in the environment and it cause serious toxicity to plants. Salicylic acid (SA) plays an important role in many plant growth processes involved in plant defence against heavy metal or metalloid stress. In the present study, for the first time, chitosan nanoparticles was synthesised, loaded by SA and the positive role of SA on growth and phytoremediation efficiency of Isatis cappadocica against As toxicity were evaluated. The highest arsenate treatment (1200 µM) caused a decrease in plant biomass that, however, its combined application with salicylic acid nanoparticles (SANPs) substantially increase in shoot height, root length and their biomass production compared with As stressed plants. The pretreatment of SANPs by increasing arsenate supply, simultaneously increased the As concentration in roots and shoots of I. cappadocica which reached a maximum of 705 and 1188 mg/kg, respectively. This results suggest that high levels of As stress induce stress status in I. cappadocica which SANPs pretreatment application limit these toxic effects of As. Therefore, SANPs has a significant beneficial effect on the growth and phytoremediation efficiency of I. cappadocica subjected to As stress.
Journal of Plant Process and Function, Oct 10, 2018
In present study, growth, arsenic accumulation, and antioxidant responses in root of Isatis cappa... more In present study, growth, arsenic accumulation, and antioxidant responses in root of Isatis cappadocica were investigated in response to application of arsenate and phosphate. Reduction in root dry weights was significant with 1200 µM arsenate and 5 µM phosphate treatments. Phosphate had a steady effect on root dry weight improvement, especially in high arsenate treatments ≥ 200 μM. As concentrations in roots increased with increasing arsenate supply levels, growth decreased markedly with increasing phosphate in each arsenate treatment. Applied arsenate induced oxidative stress, which caused increasing the concentrations of hydrogen peroxide (H 2 O 2) and malondialdehyde (MDA). The activities of antioxidant enzyme such as catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX) in Isatis cappadocica roots increased significantly from 200-800 µM arsenate and 5 µM phosphate treatments while their activities were decreased at 1200 µM arsenate and 5 µM phosphate, compared with the control plants. The phosphate mediated decline of CAT, POD and APX activities, which could be an important factor in regulating As-induced oxidative stress in roots. Our results concluded that, I. cappadocica has a great capability to tolerance and accumulation As. Also, application of phosphate has a clear vital role in oxidative stress reduction in roots of exposed I. cappadocica to arsenate.
Environmental Science and Pollution Research, Apr 26, 2022
The current study was conducted to investigate the role of sulfur (S) and reduced glutathione (GS... more The current study was conducted to investigate the role of sulfur (S) and reduced glutathione (GSH) in mitigating arsenic (As) toxicity in Isatis cappadocica and Erysimum allionii. These plants were exposed for 3 weeks to different concentrations (0, 400 and 800 μM) of As to measure fresh weight, total chlorophyll, proline and hydrogen peroxide (H2O2) content, As and S accumulation, and guaiacol peroxidase (POD) and glutathione S-transferase (GST) along with the supplementation of 20 mg L−1 of S and 500 μM of GSH. Results revealed the significant reduction of fresh weight (especially in E. allionii), activities of POD and GST enzymes and proline content as compare to control. However, the application of S and GSH enhanced the fresh weight. Inhibition in H2O2 accumulation and improvement in antioxidant responses were measured with the application of S and GSH. Hence, the supplementation of S and GSH enhanced fresh weight and total chlorophyll in both I. cappadocica and E. allionii by alleviating the adverse effects of As stress via decreased H2O2 content and restricted As uptake.
Isatis cappadocica is known to be a potential accumulator of arsenic (As), but all mechanisms of ... more Isatis cappadocica is known to be a potential accumulator of arsenic (As), but all mechanisms of As detoxification have not been investigated yet. Current study investigated the effects of arsenate and phosphate interaction on growth, lipid peroxidation, As accumulation, phosphorus (P) accumulation, and the activities of some antioxidant enzymes in I. cappadocica. Plants were exposed to 50, 200, 800 & 1200 μmol L −1 arsenate and 5, 50, 200, 800 & 1600 μmol L −1 phosphate for 28 days in hydroponic system. At phosphate concentration of 1600 µM, biomass production and chlorophyll content increased demonstrating clearly that phosphate was able to provide protection against As toxicity in I. cappadocica. In case of joint application of highest phosphate level (1600 µM) with arsenate, the As accumulation and then lipid peroxidation were decreased as compared to samples treated with arsenate and low phosphate level (5 µM). The activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and glutathione reductase (GR) increased with increasing arsenate supply levels. Addition of P decreased activities of SOD, APX and CAT, while high phosphate treatments had a positive effect on GR activity which may be due to regulation of glutathione biosynthesis within the plants. In conclusion, I. cappadocica has a great capability to tolerate As in high concentration (1200 μmol L-1). High 3 arsenate treatment (800-1200 µM) could cause an increasing oxidative stress, which can be scavenged by the antioxidant enzyme. Furthermore, P may affect nutrient condition and As accumulation in plants, thus indirectly affect As-induced oxidative stress.
Ecotoxicology and Environmental Safety, Dec 1, 2020
Spanish publications providing grounding and theoretical framework for research on information us... more Spanish publications providing grounding and theoretical framework for research on information users Isabel Villaseñor-Rodríguez Monographs, papers and articles published in Spain since 1993 are examined to shed theoretical light on the approach to information users as a function of meeting user needs and measuring the degree of user satisfaction. The paper describes the most commonly cited sources and discusses the approach to the topic, whether general or specific. Characteristic features of authorship of these writings as well as their chronological development are also examined.
Isatis cappadocica has been reported to be an arsenic (As) hyperaccumulator. Antioxidant enzymes ... more Isatis cappadocica has been reported to be an arsenic (As) hyperaccumulator. Antioxidant enzymes and compounds have been proposed to play an important role in the detoxification and tolerance of As. In the present study, As-induced oxidative stress and antioxidant responses were investigated on I. cappadocica grown hydroponically in response to application of arsenate (0-1200 μmol). As accumulation increased with an increase in arsenate concentration in the medium. Along with a significant increase in arsenate concentration, a build up in hydrogen peroxide, indicators of oxidative stress, was observed. The activity of superoxide dismutase and peroxidase was induced after arsenate treatment, reached a maximal value at 800 μmol arsenate and then declined at the highest arsenate treatment. Glutathione reductase activity and contents of non-enzymatic antioxidants (carotenoids, flavonoids and anthocyanins) increased significantly as arsenate concentration augmented. These results indicated that high efficient antioxidant system may play significant roles in As detoxification and improve I. cappadocica tolerance against As toxicity.
ABSTRACT Arsenic is considered as one of the most important environmental contaminant elements. S... more ABSTRACT Arsenic is considered as one of the most important environmental contaminant elements. Some plant species can grow in arsenic contaminated soils and they are able to reduce arsenic toxicity. In this study, a hydroponic experiment was conducted on Isatis cappadocica, a newly-discovered As hyperaccumulator. Accordingly, we conducted this experiment to compare the interaction of effect of arsenic and phosphorus on total chlorophyll and antioxidant compounds (carotenoids, anthocyanin and proline) of I. cappadocica for better understanding the mechanisms applied by this species. Therefore, the plants were grown for 6 weeks in a medium, embedded with combinations of 50, 200, 800 and 1200 μmol l −1 arsenic and 5, 50, 200, 800 and 1600 μmol l −1 phosphorus, respectively. The highest concentration of arsenic was obtained in plants treated with 1200 μmol l −1 As and 5 μmol l −1 phosphorus. Increasing arsenic concentration in the medium led to increase in antioxidant compounds. The ability of Isatis to accumulate more than 700 mg kg -1 arsenic in the shoots, illustrates the high resistance of this plant to arsenic and the existence of efficient mechanisms including increase of antioxidant compounds.
Metalloid arsenic is considered as one of the most important environmental contaminant compounds.... more Metalloid arsenic is considered as one of the most important environmental contaminant compounds. Some plants with high concentrations of arsenic accumulation in their shoots, have the ability to purify arsenic-contaminated areas. Due to the chemical similarity between arsenate and phosphate, similar behavior has been observed by plant uptake system. In this study, hydroponic experiment was conducted of Isatis cappadocica, a newly-discovered As hyperaccumulator. Accordingly, we conducted this experiment to compare the interaction of arsenic and phosphorus on antioxidant compounds of I. cappadocica. Therefore, the plants were grown for 6 weeks in a medium, embedded with combinations of 50, 200, 800 & 1200 μmol l−1 arsenic and 5, 50, 200, 800 & 1600 μmol l−1 phosphorus, respectively. The dry weight, hydrogen peroxide, antioxidant compounds and the arsenic and phosphorus concentration of harvestable parts were determined. The highest concentration of arsenic was obtained in plants trea...
International Journal of Phytoremediation, Jan 21, 2021
NADPH-dependent superoxide production by intact human neutrophils is inhibited by DPI (diphenylen... more NADPH-dependent superoxide production by intact human neutrophils is inhibited by DPI (diphenyleneiodonium), when stimulated by either FMLP (N-formylmethionyl-leucyl-phenylalanine) or PMA (phorbol 12-myristate 13-acetate). Addition of 10 ,#M-DPI abolished the reduction of both the FAD and the cytochrome b components of the NADPH oxidase. DPI inhibition of the oxidase was associated with defective aerobic killing of staphylococci by human neutrophils. Anaerobic killing, phagocytosis, chemotaxis and motility were relatively unaffected by 10,uM-DPI. Degranulation of the azurophil and specific granules, induced by the soluble stimuli FMLP or PMA, and by particulate stimuli was decreased by the presence of DPI. The above effects of DPI on human neutrophils are similar to those found in chronic granulomatous disease. Bactericidal assays The Oxford strain of Staphylococcus aureus (N.C.T.C. 6571) was used in bactericidal assays. Bacteria were prepared and bactericidal assays performed as described by Williams et al. (1985), with human in place of bovine neutrophils. Lysostaphin was used to remove extracellular staphylococci in the determination of intracellular survival (Tan et al., 1971). Neutrophils (3.3 x 106/ml) and bacteria (106/ml) were suspended in 20 mM-phosphate-buffered saline (0.137 M-NaCl/2.68 mM-KCI/8. 1 mM-Na2HPO4/ 1.47 mM-KH2PO4, pH 7.0) containing 1.26 mM-CaCl2, 0.41 mM-Vol.
Environmental Science and Pollution Research, May 26, 2019
A hydroponic experiment was conducted to explore the interactive effects of selenium (Se) supplem... more A hydroponic experiment was conducted to explore the interactive effects of selenium (Se) supplementation (0, 5, and 10 μM) and arsenic (As) toxicity (0, 200, and 400 μM) on the growth, accumulation, and oxidative damage along with defense mechanisms of metallicolous (MP) and non-metallicolous population (NMP) of Isatis cappadocica, an As-hyperaccumulator, and Brassica oleracea as reference brassica. The results revealed that As stress significantly hampered plant growth particularly in B. oleracea. It reduced plant growth due to enhanced oxidative load of As-stressed plants. Between the two Isatis populations, metallicolous plants accumulated significantly higher As, however with considerably low growth defects. Furthermore, Se supplementation counteracted the adverse effects of stress on growth and physiological performance of all studied plants. Addition of Se, particularly at higher dose (10 μM), significantly suppressed root As uptake and slightly its accumulation in shoots of B. oleracea plants treated with 400 μM As, and thus improved growth characteristics of stressed plants. Under As stress, Se supplementation increased the activities of enzymatic (peroxidase (POD) and glutathione reductase (GR)) and nonenzymatic (anthocyanins and total flavonoids) antioxidants, thereby suggesting relieved As stress by reduced oxidative damage. Taken together, these results support the beneficial role of Se in the regulation of As stress by improving growth, physiology, and antioxidant capacity, and highlight its significance for plants grown on such metal-contaminated soils.
Arsenic (As) and cadmium (Cd) belong to the group of major pollutants extremely toxic to plants. ... more Arsenic (As) and cadmium (Cd) belong to the group of major pollutants extremely toxic to plants. Metal hyperaccumulating plants play an important role in phytoextraction of heavy metals. Silicon (Si) plays an important role in the amelioration of heavy metal stress through physio-biochemical mechanisms, which remain poorly understood in hyperaccumulators. The main purpose of this study was to determine the impact of Si on growth and performance of As hyperaccumulator Isatis cappadocica Desv., exposed to As and Cd. Results showed that Si (especially at 1 mM level) alleviated the harmful impact of As/Cd and significantly increased the root and shoot biomass, root and shoot length and chlorophyll contents of I. cappadocica by enhancing the plant defense mechanisms. Between the two investigated harmful elements, As was accumulated in plant parts significantly more than Cd, however with considerably lower toxic growth effects. The As/Cd concentration, bioaccumulation and translocation factor and total As content both in roots and shoots of Si-supplied plant were significantly reduced as a protective mechanism, especially in Cd exposed plant. In comparison with single As/Cd treatment, Si supply reduced H2O2 content, increased total soluble protein content and enhanced glutathione S-transferase activity in shoots. The results of this study clearly showed that Si minimized As/Cd uptake and root to shoot translocation, and therefore Si cannot enhance the phytoextraction potential of this plant species. Additionally, Si-improved growth and reduced oxidative damages caused by excess of As and Cd suggested that the similar mechanisms of metal(loid) alleviation are adopted in hyperaccumulators as well as non-hyperaccumulating plants.
Arsenic (As) is a toxic metalloid that severely hampers plant growth and also poses health risks ... more Arsenic (As) is a toxic metalloid that severely hampers plant growth and also poses health risks for humans through the food chain. Although nitric oxide (NO) is known to improve plant resistance to multiple stresses including metal toxicity, little is known about its role in the As tolerance of hyperaccumulator plants. This study investigates the role of the exogenously applied NO donor, sodium nitroprusside (SNP), in improving the As tolerance of Isatis cappadocica, which have been reported to hyperaccumulate As. Exposure to toxic As concentrations significantly increases NO production and causes damage to the cell membrane, as indicated by increased hydrogen peroxide (H2O2) and malondialdehyde (MDA) concentration, thereby reducing plant growth. However, the addition of SNP improves growth and alleviates As-induced oxidative stress by enhancing the activity of superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR), glutathione S-transferase (GST), glutathione (GSH), as well as proline and thiol concentration, thereby confirming the beneficial role played by NO in enhancing As stress tolerance. Furthermore, the As-induced decrease in growth and the increase in oxidative stress were more marked in the presence of bovine hemoglobin (Hb; a NO scavenger) and N(G)-nitro-L-arginine methyl ester (L-NAME; a NO synthase inhibitor), thus demonstrating the protective role of NO against As toxicity. The reduction in NO concentration by L-NAME suggests that NOS-like activity is involved in the generation of NO in response to As in I. cappadocica.
Arsenic (As) is a toxic metalloid dispersed in the environment and it cause serious toxicity to p... more Arsenic (As) is a toxic metalloid dispersed in the environment and it cause serious toxicity to plants. Salicylic acid (SA) plays an important role in many plant growth processes involved in plant defence against heavy metal or metalloid stress. In the present study, for the first time, chitosan nanoparticles was synthesised, loaded by SA and the positive role of SA on growth and phytoremediation efficiency of Isatis cappadocica against As toxicity were evaluated. The highest arsenate treatment (1200 µM) caused a decrease in plant biomass that, however, its combined application with salicylic acid nanoparticles (SANPs) substantially increase in shoot height, root length and their biomass production compared with As stressed plants. The pretreatment of SANPs by increasing arsenate supply, simultaneously increased the As concentration in roots and shoots of I. cappadocica which reached a maximum of 705 and 1188 mg/kg, respectively. This results suggest that high levels of As stress induce stress status in I. cappadocica which SANPs pretreatment application limit these toxic effects of As. Therefore, SANPs has a significant beneficial effect on the growth and phytoremediation efficiency of I. cappadocica subjected to As stress.
Journal of Plant Process and Function, Oct 10, 2018
In present study, growth, arsenic accumulation, and antioxidant responses in root of Isatis cappa... more In present study, growth, arsenic accumulation, and antioxidant responses in root of Isatis cappadocica were investigated in response to application of arsenate and phosphate. Reduction in root dry weights was significant with 1200 µM arsenate and 5 µM phosphate treatments. Phosphate had a steady effect on root dry weight improvement, especially in high arsenate treatments ≥ 200 μM. As concentrations in roots increased with increasing arsenate supply levels, growth decreased markedly with increasing phosphate in each arsenate treatment. Applied arsenate induced oxidative stress, which caused increasing the concentrations of hydrogen peroxide (H 2 O 2) and malondialdehyde (MDA). The activities of antioxidant enzyme such as catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX) in Isatis cappadocica roots increased significantly from 200-800 µM arsenate and 5 µM phosphate treatments while their activities were decreased at 1200 µM arsenate and 5 µM phosphate, compared with the control plants. The phosphate mediated decline of CAT, POD and APX activities, which could be an important factor in regulating As-induced oxidative stress in roots. Our results concluded that, I. cappadocica has a great capability to tolerance and accumulation As. Also, application of phosphate has a clear vital role in oxidative stress reduction in roots of exposed I. cappadocica to arsenate.
Environmental Science and Pollution Research, Apr 26, 2022
The current study was conducted to investigate the role of sulfur (S) and reduced glutathione (GS... more The current study was conducted to investigate the role of sulfur (S) and reduced glutathione (GSH) in mitigating arsenic (As) toxicity in Isatis cappadocica and Erysimum allionii. These plants were exposed for 3 weeks to different concentrations (0, 400 and 800 μM) of As to measure fresh weight, total chlorophyll, proline and hydrogen peroxide (H2O2) content, As and S accumulation, and guaiacol peroxidase (POD) and glutathione S-transferase (GST) along with the supplementation of 20 mg L−1 of S and 500 μM of GSH. Results revealed the significant reduction of fresh weight (especially in E. allionii), activities of POD and GST enzymes and proline content as compare to control. However, the application of S and GSH enhanced the fresh weight. Inhibition in H2O2 accumulation and improvement in antioxidant responses were measured with the application of S and GSH. Hence, the supplementation of S and GSH enhanced fresh weight and total chlorophyll in both I. cappadocica and E. allionii by alleviating the adverse effects of As stress via decreased H2O2 content and restricted As uptake.
Isatis cappadocica is known to be a potential accumulator of arsenic (As), but all mechanisms of ... more Isatis cappadocica is known to be a potential accumulator of arsenic (As), but all mechanisms of As detoxification have not been investigated yet. Current study investigated the effects of arsenate and phosphate interaction on growth, lipid peroxidation, As accumulation, phosphorus (P) accumulation, and the activities of some antioxidant enzymes in I. cappadocica. Plants were exposed to 50, 200, 800 & 1200 μmol L −1 arsenate and 5, 50, 200, 800 & 1600 μmol L −1 phosphate for 28 days in hydroponic system. At phosphate concentration of 1600 µM, biomass production and chlorophyll content increased demonstrating clearly that phosphate was able to provide protection against As toxicity in I. cappadocica. In case of joint application of highest phosphate level (1600 µM) with arsenate, the As accumulation and then lipid peroxidation were decreased as compared to samples treated with arsenate and low phosphate level (5 µM). The activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and glutathione reductase (GR) increased with increasing arsenate supply levels. Addition of P decreased activities of SOD, APX and CAT, while high phosphate treatments had a positive effect on GR activity which may be due to regulation of glutathione biosynthesis within the plants. In conclusion, I. cappadocica has a great capability to tolerate As in high concentration (1200 μmol L-1). High 3 arsenate treatment (800-1200 µM) could cause an increasing oxidative stress, which can be scavenged by the antioxidant enzyme. Furthermore, P may affect nutrient condition and As accumulation in plants, thus indirectly affect As-induced oxidative stress.
Ecotoxicology and Environmental Safety, Dec 1, 2020
Spanish publications providing grounding and theoretical framework for research on information us... more Spanish publications providing grounding and theoretical framework for research on information users Isabel Villaseñor-Rodríguez Monographs, papers and articles published in Spain since 1993 are examined to shed theoretical light on the approach to information users as a function of meeting user needs and measuring the degree of user satisfaction. The paper describes the most commonly cited sources and discusses the approach to the topic, whether general or specific. Characteristic features of authorship of these writings as well as their chronological development are also examined.
Isatis cappadocica has been reported to be an arsenic (As) hyperaccumulator. Antioxidant enzymes ... more Isatis cappadocica has been reported to be an arsenic (As) hyperaccumulator. Antioxidant enzymes and compounds have been proposed to play an important role in the detoxification and tolerance of As. In the present study, As-induced oxidative stress and antioxidant responses were investigated on I. cappadocica grown hydroponically in response to application of arsenate (0-1200 μmol). As accumulation increased with an increase in arsenate concentration in the medium. Along with a significant increase in arsenate concentration, a build up in hydrogen peroxide, indicators of oxidative stress, was observed. The activity of superoxide dismutase and peroxidase was induced after arsenate treatment, reached a maximal value at 800 μmol arsenate and then declined at the highest arsenate treatment. Glutathione reductase activity and contents of non-enzymatic antioxidants (carotenoids, flavonoids and anthocyanins) increased significantly as arsenate concentration augmented. These results indicated that high efficient antioxidant system may play significant roles in As detoxification and improve I. cappadocica tolerance against As toxicity.
ABSTRACT Arsenic is considered as one of the most important environmental contaminant elements. S... more ABSTRACT Arsenic is considered as one of the most important environmental contaminant elements. Some plant species can grow in arsenic contaminated soils and they are able to reduce arsenic toxicity. In this study, a hydroponic experiment was conducted on Isatis cappadocica, a newly-discovered As hyperaccumulator. Accordingly, we conducted this experiment to compare the interaction of effect of arsenic and phosphorus on total chlorophyll and antioxidant compounds (carotenoids, anthocyanin and proline) of I. cappadocica for better understanding the mechanisms applied by this species. Therefore, the plants were grown for 6 weeks in a medium, embedded with combinations of 50, 200, 800 and 1200 μmol l −1 arsenic and 5, 50, 200, 800 and 1600 μmol l −1 phosphorus, respectively. The highest concentration of arsenic was obtained in plants treated with 1200 μmol l −1 As and 5 μmol l −1 phosphorus. Increasing arsenic concentration in the medium led to increase in antioxidant compounds. The ability of Isatis to accumulate more than 700 mg kg -1 arsenic in the shoots, illustrates the high resistance of this plant to arsenic and the existence of efficient mechanisms including increase of antioxidant compounds.
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