elham mohajel kazemi
University of Tehran, Agriculture & Natural Resources, Department Member
Stevia rebaudiana Bertoni is a famous medicinal plant for its low calorific value compounds which are named steviol glycosides (SGs) and they are 150-300 times sweeter than sugar. Among various SGs, stevioside and rebaudioside A... more
Stevia rebaudiana Bertoni is a famous medicinal plant for its low calorific value compounds which are named steviol glycosides (SGs) and they are 150-300 times sweeter than sugar. Among various SGs, stevioside and rebaudioside A considered to be the main sweetening compounds. Soil salinity is one of the most essential stress in the world. Salinity affects the survival and yield of crops. In current study the effects of salinity and osmotic stress caused by different concentration of NaCl (0, 20, 40, 60 and 80 mM) on morphological traits, genes expressionand amount of both stevioside and rebaudioside Aunder in vitro conditions has been investigated. The morphological traits such as bud numbers, root numbers, shoot length (after 15 and 30 days) were evaluated. With increasing salinity, the values of all studied morphological traits decreased. To investigation of UGT74G1 and UGT76G1 genes expression that are involved in the synthesis of SGs, RT-PCR was done and there were significant ...
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Rapid commercialization, industrialization and the use of nanotechnology has led to an increase in the distribution of nanoparticles (NPs) in the environment. The most common metal oxide NPs which is present within products is Titanium... more
Rapid commercialization, industrialization and the use of nanotechnology has led to an increase in the distribution of nanoparticles (NPs) in the environment. The most common metal oxide NPs which is present within products is Titanium dioxide (TiO2). TiO2 NPs have photocatalytic nature and can affect plant growth. The current study investigated the morphological, anatomical and biochemical features of Baby sun rose (Aptenia cordifolia) after exposure to different concentrations of TiO2 nanoparticles (0, 1, 5, 10 and 20 mg L−1). Treatment with TiO2 NPs showed changes in the morphological features and increased photosynthetic pigmentation within the plant. An increase in the level of phenolics (12%) and flavonoid compounds (13%) was observed when plants were treated with moderate levels of TiO2 NPs. A reduction in the diameter of the vascular bundles and increased thickening of the transverse wall were observed in several samples. The number of scattered vascular bundles in the stems increased. The morphological, biochemical, and anatomical responses of Baby sun rose indicates that plants can adapt to environments contaminated with up to 20 mg L−1 TiO2 NPs. The cultivation of Baby sun rose plants in environments polluted with TiO2 NPs is recommended. This study enhances the knowledge of the effect of TiO2 NPs on the growth of Baby sun rose which is an ornamental plant, widely cultivated in different regions of Iran. The results of this study suggest that contaminated environments up to 20 mg L−1 TiO2 NPs can be managed by phytoremediation. Further studies are needed to investigate this plant's tolerance strategies against stress caused by TiO2 NPs and bulk TiO2 as well as the effect of other nanoparticles on plant.
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Environmental contamination with heavy metals is of concern as plants have the ability to absorb chemical toxicants facilitating the entry of toxic metals into the food chain. Lettuce (Lactuca sativa Linn.) was cultured in four nutrient... more
Environmental contamination with heavy metals is of concern as plants have the ability to absorb chemical toxicants facilitating the entry of toxic metals into the food chain. Lettuce (Lactuca sativa Linn.) was cultured in four nutrient solutions containing different concentrations of cadmium (0, 3, 6, and 9 mmol). The impact of heavy metal on the morphological features, antioxidant properties and antioxidant enzymes activity were investigated with primary focus on superoxide dismutase, ascorbate peroxidase, peroxidase and catalase enzymes. In silico methods were utilized in the study of the genes of these enzymes. Significant changes were observed in the morphological features of the plant with plants appearing stunted, more spherical and yellow in colour. A decrease in the dry mass of the plant was also detected. The Translocation factor (TF) for cadmium was significantly high in lettuce. Enhanced antioxidant enzymatic activity suggests that these enzymes are integrally involved in the defense mechanism of the plant to heavy metal stress. Also observed was an increase in total soluble protein, and total phenolic content. Total flavonoid content was not significantly affected. Fourteen genes encoding for ascorbate peroxidase and nineteen genes for superoxide dismutase were identified in lettuce. These enzymes varied from each other with regards to the number of exons and amino acids present, as well as their location within the cell. Plants exhibit various response mechanisms to combat heavy metal contamination.
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Nano-graphene oxide (NGO) is an engineered nanostructure that is used in various fields including biology, chemistry, medicine, and environmental protection. This kind of highly used nanomaterial (NM) is being released and accumulated... more
Nano-graphene oxide (NGO) is an engineered nanostructure that is used in various fields including biology, chemistry, medicine, and environmental protection. This kind of highly used nanomaterial (NM) is being released and accumulated gradually in nature and can have some adverse influences on living organisms including plants. Soybean as a cultivated plant with a high importance in food industry, but sensitive to stresses, was chosen in the present study to be examined in terms of proteomic, biochemical, and anatomical properties under the NGO stress. Accordingly, a 2-dimensional gel electrophoresis (2-DE) approach was adopted for proteomic analysis of the NGO treated soybean roots, where significant changes were observed in the abundance of 48 proteins. MALDI TOF/TOF analysis revealed the upregulation of the proteins involved in the redox regulation in plants. Furthermore, anatomical examination of soybean roots under light microscopy showed that the NGO could enter into the root epidermis through the apoplastic pathway and accumulated in some parts of the root. With increasing NGO concentration, the diameter of the vascular apertures increased and then decreased at higher concentrations. To evaluate the toxicity of NGO, some of the growth parameters including fresh and dry weight, and height of the shoots, as well as some stress-related biochemical properties such as H2O2 production, antioxidant enzymes activity, and phenolics and flavonoids contents were measured. The results indicated that NGO could cause an oxidative stress, which can be considered a toxic effect evoking antioxidative and detoxification mechanisms in soybean.
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Regarding different ultraviolet radiations (UV), UV-B plays the most effective role on the earth and bio-plant, which needs sunshine. These radiations have a negative effect on plant growth while they mostly affect the processes such as... more
Regarding different ultraviolet radiations (UV), UV-B plays the most effective role on the earth and bio-plant, which needs sunshine. These radiations have a negative effect on plant growth while they mostly affect the processes such as genetic activities, cellular metabolism, plant anatomy and morphology, and ultimately the whole plant growth. The present study investigated the effects of UV-B stress on Aptenia cordifolia which is an ornamental and medicinal plant originated from Aizoaceae family and it is resistant to some stress conditions. In this study the effect of UV-B with the intensity of 40 Lux was examined during germination and vegetative stages randomly with three replications in four intervals; 0, 45, 90,120 min and then the morphological, anatomical and phytochemical traits of the plant were examined. The results showed that when treatment level increaseed, the growth and morphological parameters such as: the percentage and rate of germination, seedling height, fresh ...
The effect of phenanthrene (PHE) as a polycyclic aromatic hydrocarbon (PAH) on the green microalgae Chlorella vulgaris was studied. After exposure of the algal cells to different concentrations (2, 10, 25 and 50 ppm) of phenanthrene for 7... more
The effect of phenanthrene (PHE) as a polycyclic aromatic hydrocarbon (PAH) on the green microalgae Chlorella vulgaris was studied. After exposure of the algal cells to different concentrations (2, 10, 25 and 50 ppm) of phenanthrene for 7 days, a significant increase occurred in the activity of the antioxidant enzymes including ascorbate peroxidase (APX), catalase (CAT) and superoxide dismutase (SOD). In addition, PHE treatments resulted in an increase in total phenol and flavonoid contents as non-enzymatic antioxidant compounds. Intriguingly, the cell density, dry weight and fresh weight of algae were enhanced at 2 ppm of PHE in comparison to control. However, the growth parameters as well as the photosynthetic pigments content of C. vulgaris gradually decreased with the enhancing concentration of phenanthrene. Flow cytometric analysis showed no significant reduction in the viability cell in the samples exposed to 50 ppm of PHE for 24 h, while chlorophyll fluorescence was significa...
Polycyclic aromatic hydrocarbons are a group of organic pollutants influencing different aspects of plants physiology. Physiological responses associated with the impact of phenanthrene (500, 1000, 1500, 2000 ppm) were analysed on Panicum... more
Polycyclic aromatic hydrocarbons are a group of organic pollutants influencing different aspects of plants physiology. Physiological responses associated with the impact of phenanthrene (500, 1000, 1500, 2000 ppm) were analysed on Panicum miliaceum L. Seed germination was delayed in all treatments and 2000 ppm of phenanthrene (PHE) significantly retarded the germination rate (28 %) compared to control. The results revealed after 30 day of cultivation, only 1500 and 2000 ppm of PHE had negative impacts on growth parameters as well as photosynthetic pigment contents. Plants exposed to 500 and 1000 ppm of PHE showed an increase in the growth parameters without any symptoms of toxicity, indicating the high tolerance of seedlings to PHE. The activities of antioxidant enzymes were elevated in treated plants. In higher concentrations, H2O2 content also increased despite a reduction in malondialdehyde content. Furthermore, PHE had no effect on root phenol and shoot flavonoid contents and on...
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ABSTRACT: Tomato (Lycopersicon esculentum) is one of the most important vegetable crops and a genetic model for improving other dicotyledonous crop plants. Agrobacterium mediated gene transformation method is considered as an effective... more
ABSTRACT: Tomato (Lycopersicon esculentum) is one of the most important vegetable crops and a genetic model for improving other dicotyledonous crop plants. Agrobacterium mediated gene transformation method is considered as an effective method for transferring foreign genes into plants. cefotaxime, commonly used for elimination of Agrobacterium tumefaciens during plant transformation. In high concentrations of cefotaxime, a decrease in regeneration, reducing the number of shoots and chlorosis were observed. We examined the effect of FeEDDHA on shoot regeneration from cotyledon explants in Falat CH cultivar. When applied during multiplication, FeEDDHA reduced chlorosis, increased the percentage of regeneration and the number of adventitious shoots. Therefore replacement of FeEDTA by FeEDHHA in media reduced the negative effects of cefotaxime.
Agrobacterium is one of the gram negative genera of soil bacteria that causes many diseases in plants through the use of horizontal gene transfer. The rol genes of A. rhizogenese, rolA, rolB and rolC, are the major causes of ‘hairy root’... more
Agrobacterium is one of the gram negative genera of soil bacteria that causes many diseases in plants through the use of horizontal gene transfer. The rol genes of A. rhizogenese, rolA, rolB and rolC, are the major causes of ‘hairy root’ symptoms in infected plants. It has been demonstrated that rol genes could have a positive effect on secondary metabolism in plants. The homologue of rol genes has also been found in some plants such as the genus Nicotiana and a member of Scrophulariaceae, Linaria vulgaris. Here we examined the effect of A. rhizogeneses rolC gene and its homologue in tobacco, trolC gene, on pigment content, production of some secondary metabolites and antioxidant activity in ‘in vitro’ cultured 4-week old seedlings. In Nicotiana plants, the transgenes were located under the control of dexamethasone inducible prompter. Methanol extracts of aerial parts of seedlings were prepared and DPPH radical scavenging method was used to evaluate the antioxidant activity. Experim...
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Tomato (Lycopersicon esculentum) is one of the most important vegetable crops and a genetic model for improving other dicotyledonous crop plants. Agrobacterium mediated gene transformation method is considered as an effective method for... more
Tomato (Lycopersicon esculentum) is one of the most important vegetable crops and a genetic model for improving other dicotyledonous crop plants. Agrobacterium mediated gene transformation method is considered as an effective method for transferring foreign genes into plants. cefotaxime, commonly used for elimination of Agrobacterium tumefaciens during plant transformation. In high concentrations of cefotaxime, a decrease in regeneration, reducing the number of shoots and chlorosis were observed. We examined the effect of FeEDDHA on shoot regeneration from cotyledon explants in Falat CH cultivar. When applied during multiplication, FeEDDHA reduced chlorosis, increased the percentage of regeneration and the number of adventitious shoots. Therefore replacement of FeEDTA by FeEDHHA in media reduced the negative effects of cefotaxime.
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Silver nanoparticles (Ag NPs) are one of the commercialized nanomaterials that are involved in quite a lot of industrial and biomedical utilization. Although some efforts have been made to examine the possible toxicity of Ag NPs on plant... more
Silver nanoparticles (Ag NPs) are one of the commercialized nanomaterials that are involved in quite a lot of industrial and biomedical utilization. Although some efforts have been made to examine the possible toxicity of Ag NPs on plant systems, but no consensus has been reached on this issue. To determine the effect of Ag NPs on antioxidant defense system in cell suspension cultures of Nicotiana tabacum, we evaluated the changes in multiple biomarkers of oxidative stress. Ag NPs were synthesized using photo reduction method and characterized as NPs with spherical shape and diameters in the range of 10-100 nm by means of XRD, DLS, and SEM techniques. A significant decline in the cell growth and viability even at low concentration of Ag NPs (5 mg L) were evident. Interestingly, a progressive decline in hydrogen peroxide levels was observed, while the contents of malondialdehyde did not change. The activity of ROS scavenging enzymes augmented with the increasing concentration of Ag N...
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Soil salinity is one of the most important constraints that limit crop production in arid and semi arid regions. Germination is the first stage in a plant's life, which can be affected by stress and as a result salinity reduces... more
Soil salinity is one of the most important constraints that limit crop production in arid and semi arid regions. Germination is the first stage in a plant's life, which can be affected by stress and as a result salinity reduces germination and delays emergence in most cultivars, however there are cultivars that can tolerate this condition. This study aimed to determine the effect of different level of salinity (0, 50, 100, 150 and 200mM NaCl) on germination and seedling growth of six tomato cultivars. The experiment followed a randomized complete block design with four replications. All the results analyzed by SPSS ver.16 statistical software and comparision of average had done by Duncan test on 5% possible level. Results confirmed that increasing NaCl concentrations reduced germination percentage, radicle and plumule length, radicle and plumule dry weight. Results showed that the highest values for these traits were from the CaljN3 cultivar, and traits in the other cultivars di...
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Abstract The color of African violet flowers (Saintpaulia ionantha Wendl.) is derived from anthocyanin pigments. A mutation in the L1 layer of the SAM suppresses the anthocyanin biosynthesis pathway and eventually generates a pinwheel... more
Abstract The color of African violet flowers (Saintpaulia ionantha Wendl.) is derived from anthocyanin pigments. A mutation in the L1 layer of the SAM suppresses the anthocyanin biosynthesis pathway and eventually generates a pinwheel phenotype of periclinal chimera (cells of different genotypes). The aim of the present research was to understand the coloration pathway of petals and how color changes with phenotype. Flower development was investigated by light and scanning electron microscopy (SEM). Expression of nine genes involved in anthocyanin biosynthesis pathway in monochromatic and pinwheel phenotypes were evaluated by Real-Time PCR. Anthocyanin present in pinwheel petals was analyzed by HPLC. Microscopic studies revealed that the ventral petals were formed before the dorsal petals and that the petal primordia separated in the early stages of floral development. Saintpaulia flower is protandry and the tapetum layer is of the secretory type. The ovules are anatropous and are within the superior ovary with lateral placentation. Gene expression analysis showed that CHS and CHI genes were expressed at all stages of floral development, but hydroxylase genes increased during intermediate stages. Biosynthetic genes were highly expressed in the purple sections of the pinwheel petals, whereas the expression of F3H gene was significantly lower in the white section. The WDR transcription factor appears to have no association with the anthocyanin biosynthesis pathway genes in the white section. HPLC analysis showed that when F3H gene expression was reduced in the white part of the petals, the product of this gene (dihydrokaempferol component) did not accumulate. Color change is one of the most effective methods to create new cultivars. Details of floral pigment biosynthesis pathway and the production of new cultivars can respond to consumer demand and market preservation.
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Rapid commercialization, industrialization and the use of nanotechnology has led to an increase in the distribution of nanoparticles (NPs) in the environment. The most common metal oxide NPs which is present within products is Titanium... more
Rapid commercialization, industrialization and the use of nanotechnology has led to an increase in the distribution of nanoparticles (NPs) in the environment. The most common metal oxide NPs which is present within products is Titanium dioxide (TiO2). TiO2 NPs have photocatalytic nature and can affect plant growth. The current study investigated the morphological, anatomical and biochemical features of Baby sun rose (Aptenia cordifolia) after exposure to different concentrations of TiO2 nanoparticles (0, 1, 5, 10 and 20 mg L-1). Treatment with TiO2 NPs showed changes in the morphological features and increased photosynthetic pigmentation within the plant. An increase in the level of phenolics (12%) and flavonoid compounds (13%) was observed when plants were treated with moderate levels of TiO2 NPs. A reduction in the diameter of the vascular bundles and increased thickening of the transverse wall were observed in several samples. The number of scattered vascular bundles in the stems increased. The morphological, biochemical, and anatomical responses of Baby sun rose indicates that plants can adapt to environments contaminated with up to 20 mg L-1 TiO2 NPs. The cultivation of Baby sun rose plants in environments polluted with TiO2 NPs is recommended. This study enhances the knowledge of the effect of TiO2 NPs on the growth of Baby sun rose which is an ornamental plant, widely cultivated in different regions of Iran. The results of this study suggest that contaminated environments up to 20 mg L-1 TiO2 NPs can be managed by phytoremediation. Further studies are needed to investigate this plant's tolerance strategies against stress caused by TiO2 NPs and bulk TiO2 as well as the effect of other nanoparticles on plant.
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Saintpaulia ionantha H. Wendl synonym Streptocarpus ionanthus has been considered an ornamental plant. The PHANTASTICA PHAN gene has a significant role in the formation of plant organs adaxial?abaxial polarity. In the present study the... more
Saintpaulia ionantha H. Wendl synonym Streptocarpus ionanthus has been considered an ornamental plant. The PHANTASTICA PHAN gene has a significant role in the formation of plant organs adaxial?abaxial polarity. In the present study the PHAN gene was identified in Saintpaulia for the first time using PCR. To determine the expression pattern of the PHAN gene, gene expression was compared at 3 developmental stages using real time PCR. For in silico analyses, protein characteristics, secondary and 3D structures of protein, intracellular localization, and the phylogenetic tree were investigated using bioinformatics tools. The partial CDS of PHAN gene contained 756 nucleotides, a predicted protein encoded with 252 amino acids with a molecular weight of 28,474 Da. The presence of the HTH MYB-type motif in this sequence indicated that the PHAN protein belonged to the MYB family. The secondary structure of the PHAN protein was composed of 45% ?-helix. The predicted PHAN protein 3D structure revealed that this protein can bind to nucleic acids. The binding site sequence included amino acids 10 R , 12 W , 13 H , 66 W , and 67 K . The intracellular localization of PHAN protein is believed to be in the nucleus. Phylogenetic analysis revealed that species belonging to each family were grouped in same clade. Gene expression revealed that in the later stages of petal development, expression was reduced. The results suggest that the expression pattern of the PHAN gene is that of adaxial?abaxial symmetry initiation during petal development as well as in the leaves of Saintpaulia. It appears that genetic engineering using biotechnology would be beneficial for improving the ornamental value of Saintpaulia.
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Reversed-phase preparative high-performance liquid chromatography (HPLC) of the methanol extract of the aerial parts of Euphorbia petiolata Banks... more
Reversed-phase preparative high-performance liquid chromatography (HPLC) of the methanol extract of the aerial parts of Euphorbia petiolata Banks & Soland, an endemic Iranian medicinal plant, yielded ten free radical scavengers including eight flavonoid glycosides myricetin 3-O-glucoside (1), kaempferol 3-O-(2-O-galloyl)-glucoside (2), myricetin 3-O-rhamnoside (3), quercetin 3-O-glucoside (4), kaempferol 3-O-glucoside (5), quercetin 3-O-rhamnoside (6), kaempferol 3-O-rhamnoside (7), and quercetin 3-O-rutinoside (10), a coumarin esculetin (8) and a phenylpropanoid 2-hydroxydihydrocinnamic acid (9). The structures of these compounds were elucidated conclusively by spectroscopic means and also by direct comparison of their spectroscopic data with respective published data. The free radical scavenging properties of these compounds were assessed by the 2,2-diphenyl-1-picrylhydrazyl assay.
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Cicer arietinum L. (chickpeas) is a widely consumed legume that is impacted by heavy metal contaminants such as cadmium. Cadmium is a chemical hazard and can severely impact the morphological and physiological features of the plant. C.... more
Cicer arietinum L. (chickpeas) is a widely consumed legume that is impacted by heavy metal contaminants such as cadmium. Cadmium is a chemical hazard and can severely impact the morphological and physiological features of the plant. C. arietinum L. were exposed to cadmium and its impact on plant growth and antioxidant enzyme activity evaluated. Bioinformatic studies were performed to further understand the mechanism by which the plant combats heavy metal stress. Observed morphological changes included stunted growth, poor root development and yellowing of the plant. The study also revealed that increased cadmium resulted in a decline in mineral transportation to aerial regions of the plant. Antioxidative enzyme activity (peroxidase, superoxide dismutase, catalase, ascorbate peroxidase) increased in the leaves suggesting that these enzymes play an integral role in combatting heavy metal contamination. These research showed chickpea has a relatively high adsorption capacity for cadmiu...