Search

Abstract Drought stress markedly affects plant growth and crop production. In turn, treatment with some metal‐based nanoparticles (NPs) such as TiO2‐NPs could improve the plant tolerance against drought stress. In the present study, the effects of different levels of moisture regime (40%, 60%, and 90% field capacity [FC]) in conjunction with various concentrations of TiO2‐NPs (0, 5, 10, 20, and 40 mg. L−1) on chickpea were studied. Exposure of drought‐challenged chickpea plants to TiO2‐NPs raised antioxidant enzyme activity compared with plants grown under drought without TiO2‐NP treatment. The highest activity of ascorbate peroxidase (APX) was observed at 40% FC and application of 40 mg. L−1 TiO2‐NPs. Moreover, peroxidase (POX) activity has increased with the enhancing concentration of TiO2‐NPs to 20 mg. L−1 at 90% FC. In comparison, the application of 40 mg. L−1 TiO2‐NPs and decreasing levels of FC caused a rise in the activity of superoxide dismutase (SOD). Exposure to TiO2‐NPs raised the amount of total phenols and 2,2‐diphenyl‐1‐picryl‐hydrazyl‐hydrate (DPPH) at different levels of moisture regime. The content of malondialdehyde (MDA) at 60% FC has decreased by 22% after treatment with 20 mg. L−1 TiO2‐NPs compared with control plants. Also, treatment with TiO2‐NPs heightened the proline content, and the highest amount of proline was obtained at 40% FC by applying 20 mg. L−1 NPs. The treatment with TiO2‐NPs in the moisture regimes led to higher chlorophyll and carotenoid production in chickpea plants. Taken together, the application of TiO2‐NPs could raise the defense potential of chickpea plants against oxidative stress caused by the generation of reactive oxygen species.

Introduction: The plant species Cyamopsis tetragonoloba L. (Fabaceae) is a source of guar gum that has a variety of applications in the pharmaceutical industry because of its therapeutic properties. Other parts of the plant are also used as food and fodder. This study was conducted to evaluate some physiological changes and gum production of guar in response to foliar spraying with synthesized zinc oxide nanoparticles (ZnO-NPs).Methods: ZnO-NPs were synthesized using guar gum by the co-precipitation method. The properties of the ZnO-NPs were investigated using various analytical techniques, including ultraviolet-visible spectroscopy (UV-Vis), scanning electron microscopy (SEM), transmission electron microscope (TEM), energy dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The nanoparticles were sprayed on the leaves of the Saravan landrace of guar to study their effects on the physiological properties of the plant. The experiments were performed in a completely randomized design with three replications.Results: Treatment of plants with ZnO-NPs resulted in an improvement of some physiological properties. After exposure to 500 mg/L of ZnO-NPs, the contents of chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, gum, and soluble protein were increased by 47.88%, 78.43%, 54.37T, 29.41%, 55.08%, and 52.12%, respectively. Additionally, the amount of Zn and insoluble sugars showed the highest increase, by 3.96 and 4.31 times, respectively. In contrast, soluble sugars content as well as the activity of catalase (CAT), peroxidase (POX), and ascorbate peroxidase (APX) reduced 0.69-, 2.23-, 1.60-, and 3.91-fold, respectively.Conclusion: ZnO-NPs improved the physiological properties of guar at different concentrations, with the best effects obtained at the maximum concentration of 500 mg/L. The results of this study suggest that the ZnO-NPs synthesized by the biocompatible process are appropriate candidates to prepare guar gum to be used in pharmaceutical and therapeutic-based approaches.

Nowadays, one of the environmental problems is the production and release of persistent organic pollutants, including polycyclic aromatic hydrocarbons such as phenanthrene, into the environment. In this study, the effect of different concentrations of phenanthrene (0, 50 and 100 mg/L) on growth parameters, photosynthetic pigments, some antioxidant enzymes, and some biochemical activities of the sunflower plant were investigated. Sunflower seeds were cultivated in pots containing perlite and different concentrations of phenanthrene. The water content of pots was adjusted to field capacity using distilled water and kept in the dark for one week. Seedlings were transferred to growth chambers with controlled conditions (25–30 °C, 16/8 h light/dark photoperiod, and relative humidity of 50-60% and light intensity of 80 μmol/m2/s). After 50 days, plants were harvested and the mentioned parameters were evaluated. Growth parameters of sunflower were decreased at the level of 100 mg/L of phenanthrene. Phenanthrene treatment increased the concentration of chlorophyll a and b as well as carotenoids in sunflower compared to control plants. Concentrations of non-enzymatic antioxidant compounds in treated plants with phenanthrene showed significant changes. The activity of antioxidant enzymes including superoxide dismutase (SOD), ascorbate, peroxidase (APX) and peroxidase (POX) was significantly increased especially in the root. In conclusion, it seems that phenanthrene toxicity induces oxidative stress in the sunflower, and plants improve their enzymatic antioxidant system to moderate the stress condition. In addition, damage of cell membranes by phenanthrene leads to weakening of plants root system as well as disordering in water and nutrient uptake and finally reduction in the plant growth.

Introduction Drought stress is one of the most important environmental stresses affecting plant growth and yield. Chickpeas are drought tolerant plant, but drought as a limiting factor affects their yield. Drought stress in chickpeas reduces the length of flowering period and decrees the growth period. There are various strategies for mitigating drought stress, in which nanotechnology has received special attention in plant sciences in recent years. The use of nanoparticles in various plant species indicates their positive effects on plant growth and development. Nanoparticles are atomic or molecular assemblies with dimensions of 1-100 nanometers. Highly permeable nanoparticles increase the water uptake of nutrients and ultimately improve growth. The use of nanoparticles can be effective as a way to mitigate the effects of drought stress. Materials and methods The experiment was carried out as a factorial experiment with three replications in a completely randomized design in a greenhouse. The morphological and physiological characteristics of the plant were assessed at different levels (40, 60 and 90 percentage) of field capacity (FC). FC was measured by calculating the amount of soil humidity. The titanium dioxide nanoparticles (TiO2-NPs) are used in five concentration including 0, 5, 20, 10 and 40 mg/L. Firstly characteristics of nanoparticles were investigated by measuring zeta potential, XRD and TEM. Secondly, a 100 mg/l mother solution was prepared in deionized water. TiO2-NPs were dispersed by ultrasonic bath for 40 min before spraying the solution on the plants. The plants completely were soaked by sprayed solution 4 times each 14 days .Finally after the growth duration some morphological and physiological parameters were measured. The data were analyzed using ANOVA with Statistical Analysis System (Minitab .17) software and the significance of difference between means was determined by Tuky test. Result and discussions The results showed that the leaf area of chickpea was significantly affected by the test factors and their interactions. A 35%-increase in leaf area was observed at the lowest level of irrigation after exposure to 20 mg/L of TiO2-NPs. Chlorophyll index of chickpea was significantly affected by the test factors and their interactions. The interaction of two test factors showed that with an increase in the concentration of TiO2-NPs to 20 mg/L, chlorophyll index of chickpea was increased in all levels of irrigation. At all levels of irrigation, using the concentration of 40 mg/L of TiO2-NPs, the chlorophyll index in chickpea leaves were reduced compared to the concentration of 20 mg/L. The highest osmotic potential was observed in 40% capacity after treatment with 5 and 10 mg/L titanium dioxide nanoparticles. There were no significant differences between 40 and 20 mg/L at this level of irrigation. At all irrigation levels, the application of the nanoparticle produced the highest osmotic potential, and thus, the use of nanoparticles increases the osmotic potential compared to control plants. Osmotic regulation under the water shortage conditions decreases cellular inflammation by maintaining water and collecting material in the cell. Also, the percentage of dry weight of the whole chickpea plants was significantly affected by the test factors and their interactions. The interaction of two factors showed that with the increasing concentration of TiO2-NPs to 20 mg/L, the dry weight of chickpea in the lowest irrigation level was increased by10% compared to control plants. Stomatal conductivity in all irrigation levels had an upward trend by using TiO2-NPs. Conclusion Generally, TiO2-NPs showed a positive effect on the total dry and fresh weight of the whole chickpea plants. The application of 20 mg/L TiO2-NPs at all levels of irrigation reduced drought stress and prevented further plant losses. The application of low concentration of nanoparticles promoted plant growth and at high levels showed inhibitory effects on growth. Taken all together, due to the increasing use of chemical fertilizers in agriculture, nano compounds can be used as an appropriate alternative that increases product quality.

Abstract Background and Objective: The aim of this study was to evaluate the effects of growth-enhancing bacteria on reducing the negative effects of cadmium heavy metal in two varieties of bread wheat. Materials and Methods:The experiment was performed on a completely randomized basis with three replications in the Mohaghegh Ardabili University.The experimental factors included two wheat cultivars (Gonbad and Karim),four levels of CdCl2.H2O (0, 75, 150 and 300 µm) and three bacterial levels (control ,Azotobacter Crococum and Pseudomonas potida).The grain yield, the amount of cadmium absorbed in the root,stem and seed organs and the activity of antioxidant enzymes were measured. Results: The maximum grain yield was observed in spike using Azotobacter. Examination of the results of the effect of cadmium on the measured agricultural traits showed the maximum of these traits in the control and the minimum in the highest concentration of cadmium. The highest amount of soluble sugars in both cultivars was obtained in the presence of cadmium and the lowest amount in the control treatment and Azotobacter was superior to Pseudomonas in this regard. Bacteria reduced proline in the presence of cadmium. In the case of antioxidant enzymes, the presence of cadmium increased the amount of catalase and peroxidase but reduced the amount of polyphenol oxidase. Conclusion:In general, the presence of bacteria reduced the toxicity of cadmium and the effect of the bacterium on the absorption of cadmium was significant and it was found that the Karim cultivar was more resistant to stress than the Gonbad cultivar.

Introduction: Attributable to some critical features especially the similarity of the protein synthesis machinery between humans and microalgae, these microorganisms can be utilized for the expression of many recombinant proteins. However, low and unstable gene expression levels prevent the further development of microalgae biotechnology towards protein production. Methods: Here, we designed a novel "Gained Agrobacterium-2A plasmid for microalgae expression" (named GAME plasmid) for the production of the human interleukin-2 using three model microalgae, including Chlamydomonas reinhardtii, Chlorella vulgaris, and Dunaliella salina. The GAME plasmid harbors a native chimeric hsp70/Int-1/rbcS2 promoter, the microalgae specific Kozak sequence, a novel hybrid 2A peptide, and Int-1 and Int-3 of the rbcS2 gene in its expression cassette. Results: The obtained data confirmed that the GAME plasmid can transform the microalgae with high transformation frequency. Molecular and proteomic analyses revealed the stable and robust production of the hIL-2 by the GAME plasmid in the microalgae. According to the densimetric analysis, the microalgae can accumulate the produced protein about 0.94% of the total soluble protein content. The ELISA data confirmed that the produced hIL-2 possesses the same conformation pattern with the acceptable biological activity found naturally in humans. Conclusion: Most therapeutic proteins need post-translational modifications for their correct conformation, biological function, and half-life. Accordingly, microalgae could be considered as a cost-effective and more powerful platform for the production of a wide range of recombinant proteins such as antibodies, enzymes, hormones, and vaccines.

The impact of combinations of plant growth regulators (PGRs) on callus culture of Satureja sahendica Bornm. was investigated. In nodal explants, the response of secondary metabolite production to different concentrations of PGRs was analyzed regarding the presence and absence of polyvinylpyrrolidone (PVP). The explants were cultured on MS media in presence of auxins (2,4-dichlorophenoxyacetic acid and naphthylacetic acid) and cytokinins (thidiazuron and kinetin); which were used in equal concentrations of 0.5, 1, and 2 mg l-1. The treatment of 2 mg l-1 2,4-D + 2 mg l-1 Kin (MD3) led to the highest production of total phenolics (4.303 ± 0.449 mg GAE g-1) and flavonoids (24.903 ± 7.016 mg QE g-1). Moreover, the effect of salicylic acid (SA) on the production of secondary metabolites in cell suspension culture of Satureja sahendica was evaluated. The cell suspension culture was established by culturing the nodal-derived friable callus in the liquid medium containing different concentrations of SA (0, 100, 150, 200 µM). An inverse relationship exists between the fresh mass and secondary metabolites contents. In addition, there was a significant difference among concentrations of SA in the production of total phenolics and flavonoid compounds. SA enhances secondary metabolites production and decreases cell fresh mass.

Hyssop (Hyssopus officinalis L.) is a perennial subshrub, which is distributed across the eastern Mediterranean region to central Asia. One of the most important bioactive compounds of hyssop is diosmin, a flavone glycoside of diosmetin, with application in the field of cardiovascular therapy. Salinity as one of the most essential environmental stress factors is able to alter secondary metabolite content in plants. Therefore, we aimed to investigate the effect of salinity on the levels of total flavonoid content and diosmin in hyssop. Accordingly, salinity stress was imposed by watering plants with four different concentrations of sodium chloride (NaCl) (50, 100, 150 and 200 mM) for 4 weeks. High-performance liquid chromatography (HPLC) method was used for purification of diosmin from dried leaves and measurement of it in dried shoots. Nuclear magnetic resonance (NMR) spectroscopy was applied for determination of the structure of diosmin. The obtained results showed that high salinity levels lead to a higher amount of total flavonoid and diosmin content in treated plants. Although alteration in diosmin content was not significant in treatments up to 100 mM NaCl, higher amounts of diosmin were observed in 150 and 200 mM NaCl salinity levels. We concluded that the contents of total flavonoid and diosmin were significantly elevated after exposure of hyssop plants to salt stress conditions.

In this study, the effect of different concentrations of CuO nanoparticles (0, 5, 10, 50, 100, 200 mg/L) was investigated on Nannochloropsis oculata. The results showed that the viability percentage and Chlorophyll a content was significantly decreased in the algal cells treated with CuO nanoparticles (CuO-NPs) compared to the control. The content of protein remarkable was decreased in response to CuO-NPs, while the level of phenolic compounds significantly was increased in comparison to the control. The activity of polyphenol oxidase (PPO) enzyme was raised in N. oculata cells with the increase of CuO-NPs concentration, which was accordance with the results of phenolic compounds. Also, the algal cell aggregation and the cell membrane damage were observed in the images of scanning electron microscopy (SEM). Increase of phenolic compounds and PPO activity as well as the cell aggregation probably were defense methods in this microalga in response to the stress from NPs.

Severe acute respiratory syndrome–Coronavirus 2 (SARS-CoV-2) can infect various human organs, including the respiratory, circulatory, nervous, and gastrointestinal ones. The virus is internalized into human cells by binding to the human angiotensin-converting enzyme 2 (ACE2) receptor through its spike protein (S-glycoprotein). As S-glycoprotein is required for the attachment and entry into the human target cells, it is the primary mediator of SARS-CoV-2 infectivity. Currently, this glycoprotein has received considerable attention as a key component for the development of antiviral vaccines or biologics against SARS-CoV-2. Moreover, since the ACE2 receptor constitutes the main entry route for the SARS-CoV-2 virus, its soluble form could be considered as a promising approach for the treatment of coronavirus disease 2019 infection (COVID-19). Both S-glycoprotein and ACE2 are highly glycosylated molecules containing 22 and 7 consensus N-glycosylation sites, respectively. The N-glycan structures attached to these specific sites are required for the folding, conformation, recycling, and biological activity of both glycoproteins. Thus far, recombinant S-glycoprotein and ACE2 have been produced primarily in mammalian cells, which is an expensive process. Therefore, benefiting from a cheaper cell-based biofactory would be a good value added to the development of cost-effective recombinant vaccines and biopharmaceuticals directed against COVID-19. To this end, efficient protein synthesis machinery and the ability to properly impose post-translational modifications make microalgae an eco-friendly platform for the production of pharmaceutical glycoproteins. Notably, several microalgae (e.g., Chlamydomonas reinhardtii, Dunaliella bardawil, and Chlorella species) are already approved by the U.S. Food and Drug Administration (FDA) as safe human food. Because microalgal cells contain a rigid cell wall that could act as a natural encapsulation to protect the recombinant proteins from the aggressive environment of the stomach, this feature could be used for the rapid production and edible targeted delivery of S-glycoprotein and soluble ACE2 for the treatment/inhibition of SARS-CoV-2. Herein, we have reviewed the pathogenesis mechanism of SARS-CoV-2 and then highlighted the potential of microalgae for the treatment/inhibition of COVID-19 infection.

Salt stress is one of the major limiting factors for plant production, and the quality of medicinal plants is also affected by soil salinity. Hyssop (Hyssopus officinalis L.) plants were cultivated for four weeks in perlite: sand and irrigated with Hoagland nutrient solution containing 0, 50, 100, 150, and 200 mM NaCl. Plants growth was decreased by salt stress while the leaf relative water content was not affected, and the chlorophyll content decreased only by the highest salt concentration (200 mM). Sodium was accumulated at small amounts, indicating a high ability of this species to exclude salt. Soluble sugars and proline were accumulated up to 1.6 and 4.5 fold, respectively. The antioxidant enzymes activity (peroxidase, catalase, ascorbate peroxidase) were increased by the salt treatments, particularly in the leaves. The levels of secondary metabolites (saponins, phenolics, flavonoids, anthocyanins, and iridoids) were all increased under salt stress, and the total antioxidant capacity of alcoholic extract of the leaves and roots was significantly higher in the salt-treated compared with control plants. Our results showed that hyssop is a salt-tolerant species, and the quality of this medicinal plant is improved when grown under saline conditions.

Objective Optogenetics, as a new scientific branch, uses the photoreceptors to conduct basic and applied research. Identification of the novel photoreceptors and their characteristics is a way to develop the optogenetics. Cryptochrome/Photolyase protein family DASH crypthochromes have DNA repair ability and play role in signaling pathways. Current research goal was the adequate production of the Volvox predicted DASH1 cryptochrome protein (VcCryDASH1) to use in spectroscopy studies as well as DNA repair assay. Materials and methods First, the coding sequence of VcCryDASH1 was isolated from Volvox carteri cDNA library using the specific primers and cloned into pGEX-2TK expression vector. The recombinant protein production was analyzed using two different strains of E. coli under different incubation times, using IPTG to induce the protein expression and then its solubility was investigated by SDS-PAGE. DNA binding ability of the protein was studied by alignment method. Results The appropriate production of the protein obtained in Rosetta strain at 32°C under more than 3 hours incubation. Approximately, 50 percent of the protein was insoluble under 1 and 3 hours incubations. VcCryDASH1 alignment analysis showed that there is high percentage of amino acids in this protein with DNA binding ability. Conclusion These results revealed that under optimum conditions, VcCryDASH1 has dual solubility but our approach can produce the adequate quantity of the protein in the Rosetta. Also, because of having conserved amino acids, the protein can bind to DNA, nominating it as a possible resource to design the DNA- light mediator molecules in optogenetics.

Salinity promotes the generation of reactive oxygen species (ROS) and oxidative damages of different cellular components. Thus, salt stress tolerance requires activation of antioxidative pathways to protect plant cells from damages. In this study, seedlings of Salsola aucheri were treated with 100, 200, 300, 400 and 500 mM of NaCl and consequently, the activities of some antioxidant enzymes were evaluated. Enhanced activities of catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD) were determined by the increasing salinity up to 300 mM. Furthermore, accumulation of glycinebetaine (GB) as a common response to salt stress was assessed. Accordingly, the concentration of GB enhanced by the increasing concentration of NaCl up to 300 mM and decreased at NaCl concentrations of 400 and 500 mM. Likewise, assessing the activity of betaine aldehyde dehydrogenase (BADH) as a key enzyme in the biosynthesis of GB showed that BADH activity enhanced by the increasing salinity (up to 300 mM NaCl) and decreased at the higher concentrations of NaCl. Cloning and characterization of BADH cDNA from Salsola aucheri and the expression pattern of BADH transcript were also examined. An open reading frame of 797 bp encoded a protein which showed high homology to BADH enzymes in other plants. These results suggest that the salinity tolerance of Salsola aucheri might be closely associated with the increasing function of the antioxidative system to scavenge reactive oxygen species and with the accumulation of the osmoprotectant glycinebetaine.

Introduction: Several platforms including mammalian, plant and insect cells as well as bacteria, yeasts, and microalgae are available for the production of recombinant proteins. Low efficiency of delivery systems, extracellular and intracellular degradation of foreign genes during transformation, difficulties in targeting and importing into the nucleus, and finally problems in integration into nuclear genome are the most bottlenecks of classical plasmids for producing recombinant proteins. Owing to high growth rate, no common pathogen with humans, being utilized as humans’ food, and capability to perform N-glycosylation, microalgae are proposed as an ideal system for such biotechnological approaches. Here, Agrobacterium tumefaciens is introduced as an alternative tool for transformation of the microalga Dunaliella pseudosalina. Methods: The transformation of gfp gene into the D. pseudosalina was evaluated by three strains including EHA101, GV3301 and GV3850 of A. tumefaciens. The integrating and expression of gfp gene were determined by PCR, RT-PCR, Q-PCR and SDS-PAGE analyses. Results: The T-DNA of pCAMBIA1304 plasmid was successfully integrated into the genome of the microalgal cells. Although all of the strains were able to transform the algal cells, GV3301 possessed higher potential to transform the microalgal cells in comparison to EHA101 and GV3850 strains. Moreover, the stability of gfp gene was successfully established during a course of two months period in the microalgal genome. Conclusion: Agrobacterium is introduced as a competent system for stable transformation of Dunaliella strains in order to produce eukaryotic recombinant proteins.

Salinity is one of the most important agricultural issues causing considerable yield reduction in agricultural crops. The main adverse effects of salinity are due to excess amount of sodium ions that is toxic to plant cells. Most halophytes are equipped with defense mechanisms enabling them to tolerate the salty habitats. Among grass plants, Aeluropus littoralis is a known monocots halophyte that can tolerate harsh saline conditions. In this study, salt treatment was applied in three levels of 0, 200 and 400 mM NaCl after 45 days and biological samples were collected at 7, 14 and 21 days after treatment (DAT). For microscopic analysis, the tissues were cross-sectioned and stained using methylene blue for lignified tissues and Congo red for cellulosic tissues. The amounts of Na+ and K+ were measured by flame photometer and the content of lignin was measured by polymeric thioglycolic acid derivatives method. The results showed that the amount of Na+ increased 13-fold, while the stem length, stem diameter, vascular bundle number, metaxylem diameter, phloem diameter, K+, fresh weight and dry weight decreased significantly by 35%, 48%, 59%, 19%, 25%, 45%, 64% and 55% under salt treatment, respectively. The amount of lignin in stem did not significantly change under salinity. According to these results, A. littoralis can tolerate saline habitats by different adaptation strategies like the limitation of minerals transition and reduction of plant biomass. Furthermore, the concentration of lignin in metaxylem tissues and stele parenchyma led to increased resistance of halophytes in excess amounts of Na+.

Polycyclic aromatic hydrocarbons (PAHs) are a class of organic pollutants effecting different aspects of plants physiology. To assess the physiological responses of plants to PAHs, maize (Zea mays) was treated with 25, 50, 75, and 100 ppm of pyrene and after 21 days, the activity of some antioxidant enzymes, malondialdehyde (MDA), total flavonoid, total anthocyanin, and soluble sugar contents were measured in shoots and roots of plants. Pyrene led to increase MDA content as well as CAT, POD, and SOD activities. Increase in pyrene concentration reduced all studied growth variables and significantly increased photosynthetic pigments contents of plants. Soluble sugar content was significantly higher in the shoot, while that was reduced in the roots through increasing of pyrene concentration (p < 0.05). Also, the increase of pyrene concentration decreased total flavonoid content compared to anthocyanin content. In conclusion, these findings supported the hypothesis that pyrene toxicity induces oxidative stress in the maize plant and it also increases the antioxidant systems in order to moderating stress condition. However, the antioxidant system of maize was not strong enough to eliminate all produced ROS at high concentrations, thus this caused oxidative damage to the plant and decreased its growth variables.

Callus initiation, shoot formation and plant regeneration were established for Artemisia spicigera, a traditional medicinal plant growing in Armenia, Middle-Anatolia and Iran, and producing valuable volatile organic compounds (VOCs) that are mostly represented by monoterpenoids. Optimal callus initiation and shoot production were obtained by culture of hypocotyl and cotyledon explants on MS medium comprising 0.5 mg L−1 naphthalene acetic acid (NAA) and 0.5 mg L−1 6-benzyladenine (BA). Consequently, the shoots were transferred onto the MS media supplemented with 1 mg L−1 of indole-3-butyric acid (IBA) or 1 mg L−1 of NAA. Both types of auxin induced root formation on the shoots and the resulting plantlets were successfully grown in pots. The production of VOCs in callus tissues and regenerated plantlets was studied by gas chromatography–mass spectrometry (GC-MS) analysis. Although the potential of undifferentiated callus to produce VOCs was very low, an increased content of bioactive volatile components was observed at the beginning of shoot primordia differentiation. Intriguingly, the volatiles obtained from in vitro plantlets showed quantitative and qualitative variation depending on the type of auxins used for the rooting process. The acquired quantities based on total ion current (TIC) showed that the regenerated plantlets using 1 mg L−1 NAA produced higher amounts of oxygenated monoterpenes such as camphor (30.29%), cis-thujone (7.07%), and 1,8-cineole (6.71%) and sesquiterpene derivatives, namely germacrene D (8.75%), bicyclogermacrene (4.0%) and spathulenol (1.49%) compared with the intact plant. According to these findings, in vitro generation of volatile organic compounds in A. spicigera depends on the developmental stages of tissues and may enhance with the formation of shoot primordia and regeneration of plantlets.

Introduction: Lignans and flavonoids are widely distributed phenolics in the plant kingdom. Aryltetralin type lignans (podophyllotoxin derivatives) as the major secondary metabolites of Linum species play an important role in the production of chemotherapy drugs. In the present study, lignans and flavonoid glycosides from aerial parts of Linum mucronatum subsp. orientale were isolated and identified. Methods: The phytochemical investigation has been carried out on Hexane, DCM and MeOH extracts of the plant. Separation of chemical constituents was done using different chromatography (CC, prep-TLC, GC/MS and HPLC) methods. The major compounds of dichloromethane (DCM) and methanol extracts were isolated and their structures were elucidated using co-chromatography in the presence of known lignans, HPLC and NMR techniques. Results: Our results showed that podophyllotoxin and 6-MeO-α- peltatin, as new compound, are the major lignans of the DCM extract of L. mucronatum subsp. orientale. Two new flavonoid glycosides were also elucidated in the methanolic extract. Conclusion: The DCM and methanol extracts of L. mucronatum were found to contain aryltetralin-type lignans and flavonoids. The occurrence of 6-MeO-α- peltatin and flavonoids in L. mucronatum has been reported for the first time.

Comparative floral ontogeny provides new characters for phylogenetic studies. Such studies have been useful for better understanding of floral evolution within the subfamilies of Fabaceae. However, the significance of floral ontogenetic data for evaluation of systematic position among different species of a genus has not yet been demonstrated. The aim of this study was to present a complete ontogenetic pathway of Caesalpinia gilliesii, as a member of Caesalpinioideae and to compare the results with other studied species of the genus. For this purpose, flower buds of different ages were collected and fixed in FAA. After a fixation period of 24 h, the samples were rinsed, dissected in 70% ethanol and further dehydrated in 95% ethanol prior to being stained with 0.5% nigrosin black in ethanol. The results showed that differences between ontogenetic pathways of Caesalpinia species were prominent and mostly appeared early in development. In C. gilliesii all whorls initiated unidirectionally except for petals that appeared bidirectionally. Different orders of sepal initiation have been reported for other studied species including helical, tendency towards whorl and modified unidirectional. In contrast to other studied species, C. gilliesii showed overlap in the time of initiation between different whorls. Unidirectional order of initiation and overlap of organ initiation were both advanced characters that distinguished C. gilliesii from other studied species of Caesalpinia.

Introduction: The potential health risks and toxicity of synthetic antioxidants resulted in an upsurge of interest in phytochemicals as new sources of natural antioxidants. Phenolics of Astragalus L. (Fabaceae) possess antioxidant properties and have been shown to have a protective effect against several degenerative diseases. The objective of this study was to determine total phenolics and antioxidant activity of methanolic extracts from different parts of A. compactus Lam. at different phenological phases and to investigate the correlations between antioxidation and the contents of the total phenolics. Methods: Total phenolic content (TPC) was determined using the Folin-Ciocalteau reagent and the antioxidant capacity was evaluated with the 1,1-diphenyl-2-picrylhydrazyl (DPPH) test. Results: Generally, the TPC in leaves was higher than that of the roots and flowers. TPC in leaves, roots and flowers of the species varied from 5.01-8.25, 4.29-7.89 and 4.19 μg GAE/mg DW, respectively. In addition, roots and leaves at fructification stage possessed higher TPC than vegetative and flowering stages. Therefore, the leaf extracts at fructification phase showed the highest TPC that accompanied with best antioxidant activity. In the root extracts, fructification stage was also characterized by the highest antioxidant activity. Conclusion: A positive relationship between antioxidant activity and TPC showed that phenolics were the dominant antioxidant components in the species. Results obtained suggest that A. compactus methanolic extracts may serve as potential sources of natural phenolic antioxidants and that the fructification phase could be considered as the best stage for the harvesting of this plant.

Cadmium selenide nanoparticles (CdSe NPs) were synthesized by an easy and simple method and their properties were assessed by XRD, TEM and SEM techniques. The effects of CdSe NPs as well as Cd2+ ions on Lemna minor plants were investigated. The absorption of CdSe NPs by the plants had some adverse consequences that were assessed by a range of biological analyses. The results revealed that both CdSe NPs and the ionic form of cadmium noticeably caused toxicity in L. minor. Morphological parameters as well as peroxidase (POD) activity were deteriorated. In contrast, the activities of some other antioxidant enzymes (superoxide dismutase (SOD) and catalase (CAT)) as well as the contents of total phenol and flavonoids went up. Taken all together, it could be implied that CdSe NPs as well as Cd2+ were highly toxic to plants and stimulated the plant defense system in order to scavenge produced reactive oxygen species (ROS).

Safflower, Carthamus tinctorius L., is a member of Asteraceae, cultivated mainly for its seed and flower, which are used as edible oil and for medicinal applications. Safflower is a resistant plant to the environmental stresses; therefore scientists use this plant as a model for studying the mechanism of plant resistance to the environmental stresses. Antioxidant enzyme system is one of the defense mechanisms that plants use for various environmental stresses. In this study some biochemical properties of catalase, an antioxidant enzyme system, from safflower and it sensivity to azide and cyanide was investigated. Carthamus tinctorious L.cv.IL-111 was grown hydroponically in perlite for 40 days and catalase was extracted from their leaves using phosphate buffer 0.1 M, pH 7.2. Study of pH profile, temperature and different concentration of substrate and inhibitors (azide and cynide) on catalase activity in Safflower and non-denaturant polyacrylamide gel electrophoresis of crude extract, showed that at least two isoenzymes of catalase were present in safflower leaves with optimal pH at 6.5 and 8.5, respectively. Isoenzyme active at pH 8.5 was more resistant to temperature in comparison to isoenzyme active at pH 6.5. Effects of inhibitors (azide and cynide) on catalase activity showed that isoenzyme active at pH 8.5 was more sensitive to both inhibitors (azide: 4.6 fold, and cynide: 2.6 fold) in comparison to isoenzyme active at pH 6.5.