منیره چنیانی

Ziziphora clinopodioides Lam. is a perennial plant from the Lamiaceae family, widely distributed in different regions of Iran. This research aimed to investigate the content of some phenolic derivatives (phenolic, flavonoid, flavone & flavonol, ortho-diphenol, and phenolic acid) during the vegetative growth of three populations of Z. clinopodioides belonging to North Khorasan province.

For this purpose, the seeds collected from the regions ('Darkesh and Havar', 'Teymourtash', and 'Reine') were planted in pots and harvested at two vegetative growth periods (two and five months). After the sampling, the aerial part and root were separated and the mentioned phenolic derivatives were measured by spectrophotometric methods.

The results showed that the content of phenolic derivatives is significantly affected by the type of population, plant part (aerial part and root), and age (growth stage). Therefore, the aerial part of Z. clinopodioides belonging to 'Darkesh and Havar' population, in the two-month stage, has more phenolic derivatives [total content of phenolics 11.91 mg GAE/g DW, flavonoids 13.55 mg CAT/g DW, flavone & flavonols 5.94 mg QUE/g DW, ortho-diphenols 2.95 mg GAE/g DW, and phenolic acids 2.44 mg CAE/g DW] than the five-month stage.

In general, apart from the aerial part and the root, 'Darkesh and Haver' and 'Teymourtash' populations were reported as the selected population in terms of higher phenolic derivative contents in both vegetative growth stages. These results will help to select superior populations with higher content of metabolites and optimal use in food and pharmaceutical industries.

Fodder plants have been considered due to their bioactive compounds that affect livestock nutrition and their therapeutic potential for humans. Nowadays, in fodder cropping systems, the proper time of harvesting is very important to obtain optimal performance. In order to investigate the effect of different harvesting times (one to eight weeks after initial harvesting)  on the content of some secondary metabolites (phenols, flavonoids, isoflavonoids and alkaloids) and metal elements (zinc, iron, magnesium and manganese) of alfalfa, a study was carried out based on a completely randomized design with three replications. The results showed that the concentration of these metabolites and metal elements changed significantly at different harvest times. So that the amount of total phenols increased by 2.37, 2.29, and 2.24 times in the fifth, sixth, and seventh weeks, respectively, compared to the second week. Also, the amount of total flavonoids increased by 1.89 times in the sixth week compared to the second week. The amount of total isoflavonoids in the sixth week increased by 1.75 times compared to the first week. The amount of total alkaloids in the seventh and eighth weeks compared to the first week was 10.58 and 11.75 times, respectively. Also, the maximum amount of iron element was observed in the fifth and sixth weeks, and the maximum amount of magnesium and manganese elements were observed in the sixth week. The presence of the maximum amount of these phytoestrogens and metal elements in the middle and the end stages (fifth and sixth weeks, respectively) of alfalfa flowering can be an important factor in determining the quality of fodder and determining the yield of the product, and considering their medicinal properties for humans, these stages are the most suitable harvesting times.

Salvia tebesana Bunge, as an important herb in folk medicine, is distributed in limited geographical locations in the Middle East.

In this study, three protic solvents, 80 % methanol, 80 % ethanol, and double-distilled water, were investigated to recover the phenolic constituents from S. tebesana extracts.

The antioxidant activity (estimated by total antioxidant capacity, DPPH, and FRAP radical scavenging assays) and the content of phenols, ortho-diphenols, phenolic acids, flavonoids, flavonols, and proanthocyanidins of extracts from leaves and stems of S. tebesana were investigated. After selecting the best solvent, the samples were assayed for individual flavonoid compounds (apigenin, quercetin, myricetin, and rutin) by HPLC-PDA.

Different plant extracts demonstrated strong radical scavenging activities, and the leaf extract obtained by 80% methanol showed the highest antioxidant capacity. The same extract also exhibited the most ortho-diphenol, phenolic acid, flavonoid, and proanthocyanidin contents (1598.5 ± 46.2, 742.2 ± 41.3, 487.6 ± 21.9, and 350.1 ± 31.4 mg 100 g-1 DW sample, respectively), while 80 % ethanol extract of leaves gave the most phenolic and flavonol contents (2299.2 ± 47.3 and 359.1 ± 42.3 mg 100 g-1 DW sample, respectively). The high level of flavone apigenin (466.1 ± 11.1 µg g-1 DW) and flavonol rutin (348.6 ± 10.02 µg g-1 DW) were also found in methanol extracts of leaves and are reporting for the first time in S. tebesana.

These findings warrant that S. tebesana, in particular the leaves, can be suggested as a natural preservative in dietary and medical applications with the potential to reduce oxidative stress.

The present study was performed to evaluate and compare the allelopathic effects of leaf aqueous extract and mulch of Eucalyptus (Eucalyptus globulus Labill.) on cucumber (Cucumis sativus var. beith alpha) and black nightshade (Solanum nigrum L.) seedlings in a completely randomized design. 21 days after treatment of seedlings with leaf aqueous extract (concentrations 5, 10, 15, 20 g L-1) and mulch (3% and 5% weight/volume), some morphological traits, membrane stability, proline and malondialdehyde content, total protein content and activity of polyphenol oxidase, and guaiacol peroxidase were analyzed. According to the results, although both aqueous extracts and mulch reduced the height and dry weight of aerial parts and the dry weight of roots in cucumber and black nightshade (compared to the control), the length of cucumber roots increased under the treatment of all the concentrations of aqueous extracts and mulch 3%. Evaluation of membrane stability index, proline and malondialdehyde content showed that the negative effect of mulch (3% and 5%) on black nightshade is significant. The treatment with aqueous extracts increased the activities of polyphenol oxidase and guaiacol peroxidase enzymes in cucumber (compared to the control), with the maximum ones in 20 g L-1 extract, while treatment with these extracts on black nightshade reduced the soluble protein content and enzymes studied. Overall, according to the results of this study, it can be stated that aqueous extracts showed a better ability to control black nightshade compared to leaf mulch, and it may be possible to use this type of treatment for herbicides in vegetable fields.

Nanoparticles are superior to conventional elemental forms due to the novel physicochemical properties that enable them to act as plant growth promoters. Recent research on nanomaterials has been shown both positive and negative effects. Titanium dioxide nanoparticles (TiO2 NPs) are assayed worldwide in large quantities for various purposes. This study investigated the effect of TiO2 NPs on some physiological and biochemical traits and the induction of the antioxidant systems in Origanum vulgare L. and Origanum majorana L., in a completely randomized design with three repetitions.

Surface-sterilized seeds were sown with 2 cm depth in each plastic pots filled with a 1: 1 mix of loamy soil and sand. Until reaching the appropriate physiological age, they were exposed to greenhouse conditions (16 h light/8 h dark photoperiod). Two-month-old plants were foliar sprayed with 10, 60, and 120 mg/L TiO2 NPs and harvested 14 days after the last treatment. Plants sprayed with distilled water were used as controls. Changes in the photosynthetic pigments (the content of chlorophyll a, chlorophyll b, total chlorophyll, and carotenoid), biochemical properties (the levels of membrane stability index, malondialdehyde, and proline contents), and the activity of antioxidant enzymes (Guaiacol peroxidase, ascorbate peroxidase, polyphenol oxidase, superoxide dismutase, catalase, and glutathione s-transferase) were measured in the collected samples.

The comparison of data means showed that the treatment of 60 mg/L TiO2 NPs caused the maximum amount of chlorophyll a, total chlorophyll, and carotenoids in both Origanum species. However, the highest content of chlorophyll b in O. majorana was observed in the treatment of 120 mg/L TiO2 NPs. It is worth mentioning that the negative effect of the concentration of 120 mg/L TiO2 NPs on the membrane system of two species is statistically significant and remarkable due to the leakage of electrolytes. Although the increase in the concentration of TiO2 NPs led to fewer levels of malondialdehyde in O. vulgare in comparison with O. majorana; this concentration was found to be effective to the high levels of proline in O. vulgare. Most of the antioxidant enzymes (Guaiacol peroxidase, ascorbate peroxidase, polyphenol oxidase, superoxide dismutase, and glutathione s-transferase) of O. vulgare showed their maximum activity at the concentration of 60 mg/L TiO2 NPs. However, the lower activity of catalase in O. vulgare, compared to O. majorana was remarkable.

The results of this research show that the treatment of 60 mg/L TiO2 NPs improves the physiological characteristics of the medicinal plant Origanum, including the increase of photosynthetic pigments, followed by the rate of photosynthesis and the increase of biomass. It is noteworthy that higher levels than the optimal concentrations of TiO2 NPs can lead to an increase in the levels of ROS and oxidative burst, which leads to a decrease in plant performance. Therefore, the plant response to nanoparticles depends significantly on the concentration and time of application, as well as the size, shape, and surface functionalization of the particles. Finally, O. vulgare is introduced as a more successful species due to the higher activity of antioxidant enzymes when treating TiO2 NPs.

Wheat (Triticum aestivum L.), as one of the most important cultivated crops in the world and Iran, is constantly threatened by many diseases, including Fusarium contamination. Due to the unique characteristics of nanoparticles, copper oxide nanoparticles show high antibacterial and antifungal properties. The purpose of this research was to comparatively investigate the antifungal effects of copper oxide nanoparticles and its bulk form on the suppression of Fusarium calmorum in wheat. For this purpose, a pot experiment was done with four levels (10, 250, 500, and 1000 mg L-1) of nanoparticles and bulk form of copper oxide treatments in wheat (Roshan cultivar). The results showed that the maximum inhibition of root pathogenicity was observed in a high concentration of nanoparticles as compared to bulk form. The 250 and 500 mg L-1 concentrations of copper oxide nanoparticles caused the highest stem and root length and the highest dry weight of the aerial part and root, respectively. Treatment with 10 and 250 mg L-1 nanoparticles also increased the content of chlorophyll a, total chlorophyll, carotenoid, chlorophyll stability index, membrane stability coefficient, and relative leaf water content. While the content of chlorophyll b, malondialdehyde, hydrogen peroxide, and proline increased with the increasing concentration of both nanoparticle and bulk forms. The results of this research showed that the low and medium concentrations of nanoparticles were more successful in inhibiting the aforementioned fungus than the bulk form.

This study was conducted with the aim of investigating the effect of plant hormones (IAA and BAP) and methyl jasmonate elicitor on callogenesis potential of Teucrium polium leaf explants and the content of some phenolic compounds (total phenols, o-diphenols, phenolic acids, flavonoids, and flavones) and its antioxidant capacity. Leaf explants prepared from hydroponically-grown plants were cultured on MS medium with separate and combined concentrations of IAA (0.1, 0.5 and 1 mg L-1) and BAP (0.5, 1 and 1.5 mg L-1). The treatments with the highest percentage of callogenesis and fresh and dry weight were selected as the best hormonal conditions to evaluate the effect of methyl jasmonate (50, 100 and 200 μM) on phenolic derivatives. Eight weeks after callus growth, the content of various phenolic compounds and the antioxidant capacity of the extracts (based on DPPH and FRAP assays) were measured. Although a higher percentage of callogenesis was observed in all hormonal treatments than the control, conditions "IAA0.1 + BAP1" and "IAA1 + BAP1.5" mg L-1 were with 100% callus induction. The highest fresh and dry weight of calli were in the combined treatments "IAA0.1 + BAP0.5", "IAA0.1 + BAP1", "IAA1 + BAP0.5" and "IAA1 + BAP1.5" mg L-1. The results of the second part of the experiment showed that the highest amount of phenolic compound and all its derivatives except o-diphenol was seen under the treatment of 50 μM methyl-jasmonate- in all hormonal treatments. A strong correlation was also observed between the antioxidant potentials DPPH (r2 = -0.735) and FRAP (r2 = 0.876) with the content of phenolic compounds. Therefore, methyl jasmonate as a potent elicitor can increase the synthesis of phenolic derivatives and the antioxidant capacity in Teucrium callus. So this method would be an effective technique for the supply of medicinal-phenolic compounds.

Teucrium polium, from Lamiaceae family, is a medicinal plant. Due to overexploitation, low distribution and habitat destruction, this plant, is facing extinction. Plant biotechnology and tissue culture is an alternative method for plant secondary metabolites production. The present study aimed to enhance the production of secondary metabolites and antioxidant capacity of Teucrium polium L. using methyl jasmonate and salicylic acid elicitors. Leaf explants from hydroponically cultured 4-month-old plants were inoculated on Murashige and Skoog medium (MS) containing 2, 4-dichlorofenoxy acetic acid (2, 4-D) in concentrations of 0, 0.5, 1, 1.5 mg/L alone or in combination with benzyl aminopurin (BAP) at, 0.5, 1, 1.5, 2 mg/L concentrations. According to the results, the best callus induction (100%) was achieved at MS medium containing 1.5 and 2 mg/L BAP. Calli obtained from this treatment were subsequently treated with Methyl Jasmonate or Salicylic Acid at 0, 50 and 100 μg/L concentrations. After 40 days, the content of phenolics, flavonoid compounds and total antioxidant capacity were evaluated in a completely randomized design with three replications. Based on biochemical assays, the greatest total phenol content, flavonoids and total antioxidant capacity belong to calli treated with 100 μg/L acid salicylic (SA) and after that to cali treated with 50 μg/L methyl jasmonate(MeJa), while the difference between them was significant. The results of means comparison showed applying 100 μg/L SA on calli in medium with 1.5 mg/L BAP had the greatest effect on total flavonoid content. Therefore, the use of appropriate concentrations of these elicitors can play an effective role in enhancing the medicinal compounds in Teucrium polium.

Purslane (P. oleracea) is considered as valuable plant due to its high antioxidant compounds and important fatty acids such as omega-3 and 6. Phenolic and flavonoid compounds are one of the most important constituents in the purslane. Phenolics are a large group of natural plant compounds with antioxidant and Anti-inflammatory properties. Flavonoids, as a subset of phenolic compounds, have a wide range of effects on plants, including antioxidant activity and improve resistance to environmental stresses. Callus culture is one of the important strategies for the production secondary metabolites, which are difficult to produce chemically. Plant growth regulators including auxins and cytokinins play a crucial role in the stages of plant growth. Various combinations of these two hormones are used to make the desired changes in the cultures. Studies suggest that the accumulation of secondary metabolites can be increased by the application of different elicitors in medium. Researchers reported an increase in the content of secondary metabolites such as phenol and flavonoid compounds in calli treated with elicitors such as yeast extract. The purpose of this study was to determine the best explant, medium and hormonal treatment for calli induction of purslane. The effect of different levels of yeast extract on total phenol and flavonoid content and antioxidant capacity of purslane calluses was also investigated.

Seeds of purslane plant were cultivated in a solid 1/2MS medium for the preparation of sterile seedlings. The explants from sterile seedlings including to leaves, 1 cm stem specimens and terminal buds, were placed on MS and 1/2MS medium containing 0, 0.1, 0.3, and 0.5 mg L-1 BAP and NAA. After five months, calluses were evaluated for callogenesis and some morphological traits such as color, texture, and size, fresh and dry weight. This experiment was conducted based on completely randomized design with three replications.  In the second experiment, the calluses obtained from the previous stage were transferred to MS medium with selected hormone treatment of the first experiment (0.5 mg L-1 NAA and BAP) and different levels of yeast extract (0, 125, 250, and 500 mg L-1). Total phenol and flavonoid contents of the calluses were determined by Folin-Ciocalteau and aluminum chloride methods, respectively. Furthermore, Ferric reducing antioxidant power (FRAP) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays were used to determine the antioxidant activities.

The results showed that 1/2MS medium was suitable for sterile seedling production from purslane seeds. Based on the present study, only stem explants in a medium containing BAP and NAA, produced durable calluses. The color of the resulting calluses were green and had a constant and firm texture. The highest callus percentage (90.46%), the size (21.6 mm), and fresh (1826.5 mg) and dry weight (75.33 mg) of calluses belong to MS medium containing 0.5 mg L-1 BAP and NAA. Results of the second experiment showed positive and significant effects of yeast extract on the total phenol, flavonoid contents and antioxidant activities. The highest content of total phenol (664.12 mg GAE 100g-1 DW), flavonoid (42.25 mg QE 100g-1 DW) and FRAP data (787 µmol Fe g-1 DW) were obtained from the calli treated with 500 mg l-1 yeast extract. The maximum DPPH IC50 (2.45 mg ml-1) was also observed in control. The formation of callus associated with plant species, hormonal composition, the stage of development, and the type of explants. Auxin and cytokinin as plant growth regulators are key factors for controlling cell division in tissue culture. In most studies, callus formation in purslane plant were induced in medium containing auxin and cytokinin. The presence of green calluses derived from purslane explants can be due to the formation of chloroplastids in the cells of the callus tissue that rapidly produce chloroplasts under light conditions. In the second experiment, increased phenolic and flavonoid compounds with yeast extract treatment probably resulted in increased antioxidant activity.

In the present study, 1/2MS medium is suitable for the production of sterile seedlings from purslane seeds. MS medium containing 0.5 mg l-1 BAP and NAA is the best treatment for calli induction from stem specimens. The concentration of 500 mg L-1 of yeast extract is introduced as the most effective concentration for increasing the phenolic and flavonoid content and antioxidant activity in the purslane calluses.

In order to investigate and compare the allelopathic effects of Eucalyptus (E.globuhus Labill) leaf aqueous extract and leaf mulch on corn (Zea mays L.) and wild millet (Panicum miliaceum L.), a factorial experiment was conducted in a completely randomized in Ferdowsi University of Mashhad. The experiment was carried out in seedling stage to evaluate the allelopathic effect of leaf aqueous extract (5, 10, 15 and 20 g/L) and leaf mulch (3 and 5 %) on some morphological, physiological and biochemical characteristics of the plants in this stage. Aqueous extract of Eucalyptus leaf (in most cases) and leaf mulch reduced the height of shoot, the total length of roots, the fresh weight of shoot and root, the dry weight of shoot and roots. So that the highest reduction percentage of these traits was observed in the treatment of 20 g/L aqueous extracts on wild millet. Chlorophyll a, b and total, carotenoid contents and chlorophyll stability coefficient of corn seedlings showed an incremental increase (compared to control) when treated with leaf aqueous extract. While all photosynthetic traits of millet weed decreased under all the aqueous extract and mulch treatments. The increase and decrease of membrane stability coefficient were seen in corn and wild millet respectively, when they were affected with both kind of treatments. Although the accumulation of malondialdehyde was the highest in treated millet seedlings, but corn seedlings could significantly reduce the peroxidation of membrane lipids against the stress caused by leaf extract and mulch. More increasing effects of aqueous extract and mulch on total phenol content of corn than wild millet was another results of this study. Although the total protein content of corn and weed was decreased by both treatments, but the treatment of extracts could have a better boundary between the sensitivity of plants against the allelopathic stress. A significant reduction of nitrate reductase activity in wild millet was recorded under the treatments. According to the results of this study, leaf aqueous extract or powder has different effects on biochemical, physiological and developmental traits of crops and weeds. Considering the potential of Eucalyptus leaf extract and leaf mulch on corn and wild millet, it is recommended that the plant extract can be an ideal candidate (compared with leaf powder) as a natural herbicide to control millet grass in corn fields.