جستجوی مقالات مرتبط با کلیدواژه "ترکیبات فنلی" در نشریات گروه "زراعت"

Fusarium wilt caused by Fusarium oxysporum L. is one of the most important destructive flax diseases that markedly decrease the production and yield of this crop. The cultivation of flax cultivars resistant to F. oxysporum is the most effective method for managing this disease. In this study, the changes in content of phenylalanine ammonia lyase, peroxidase and polyphenol oxidase enzymes, total protein, proline and soluble sugars were measured in 12 different genotypes of flax infected to wilt Fusarium and non-infected conditions under greenhouse conditions. The experiment was conducted in a randomized complete block design with three replications. 21 days after inoculation of the plant with the pathogen, biochemical components changes were measured by spectrophotometry. Based on the results of ANOVA, the soluble sugars content in infected genotypes was higher compared to control and healthy genotypes. Also, this parameter increased in resistant and highly resistant genotypes of flax, meanwhile this trait decreased in susceptible genotypes in contaminated conditions. The activity of phenylalanine ammonia lyase, peroxidase and polyphenol oxidase enzymes as well as proline content in leaves of resistant and highly resistant genotypes were significantly increased in wilt Fusarium infected treatment. Total protein content in non-infected genotypes of flax was higher than infected genotypes. Therefore, increasing the activity of antioxidant enzymes, proline content and soluble sugars can play a possible role in inducing resistance to Fusarium wilt disease in flax genotypes.

Introduction:

Stevia rebaudiana Bertoni is a herbaceous plant from the family Asteraceae and used as a valuable sweetener in food industry and as anti-inflammatory, antioxidant, antipyretic, anti-fungal, and antibacterial agent in medicine and pharmacology. Piriformospora indica is an endophytic fungus, which is mainly used to improve plant growth and the amount of secondary metabolites. Selenium (Se) as an micronutrient increases the antioxidant properties and plant growth and its nano form (SeNPs) is considered as a synthetic antioxidant. To evaluate the effect of Piriformospora indica inoculation and selenium nanoparticles foliar application at two concentrations of 5 and 10 mg/l on biological activities of the methanolic extract of the regenerated S. rebaudiana plants, an experiment was conducted in 2020 in Plant Physiology Research Laboratory of the Bu-Ali Sina University of Hamadan in a factorial arrangement based on completely randomized design with three replications. 

Materials and Methods:

To investigate the effects of endophytic fungus P. indica and SeNPs application, in vitro regenerated Stevia plantlets were inoculated with P. indica and foliar sprayed with SeNPs at two concentrations of 5 and 10 mg/l. Plant samples were harvested at vegetative and initial flowering stages and used for further analyses. After measuring the growth parameters, total phenol content and antioxidant activity were evaluated by Folin-Ciocalteu and DPPH radical scavenging assays, respectively. In addition, antibacterial activity of the plant methanolic extracts was studied by disc diffusion method. 

Results and Discussion:

Inoculation of P. indica and application of SeNPs together resulted in plant growth improvement and also increase in total phenol content and antioxidant activity of the Stevia plants especially at vegetative stage. In addition, the studied extracts represented good antibacterial activity against two gram-positive bacteria, Bacillus thuringiensis and Staphylococcus aureus, and one gram-negative bacterium, Escherichia coli. The highest antioxidant and antibacterial activities were observed in the Stevia plants inoculated with P. indica and also treated with SeNPs. 

Conclusion:

Regarded to the results of the present study, P. indica inoculation and SeNPs application could result to the benefits in Stevia plants. Hence, it can be concluded that the biotic and non-biotic elicitors of P. indica and SeNPs can improve the antioxidant and antimicrobial activities of the Stevia plants by increasing the amount of total phenolic compounds.

The phonological stage in which the abotic stress occurs is effective in determining the content of secondary metabolites in medicinal plants. This research deals with the effects of imposing drought stress at different phenological stages on growth and some physiological and phytochemical responses of Nepeta crispa L as a split plot design in Bu-Ali Sina University during 2019. Drought stress at three levels, including mild, moderate, and severe stress (with 80%, 60%, and 40% of field capacity, respectively) has been applied at two phenological stages (seedling establishment stage with 6 true leaves and pre-flowering stages). Results from statistical analysis show that drought stress has had a significant effect on all evaluated growth traits and phytochemical parameters of the plant including proline content, relative water content (RWC) of leaves, total phenols, flavonoids, tannins, antioxidant activities, and phenolic acids. Imposing drought stress at both phenological stages reduce plant growth, decreasing chlorophyll content and RWC. However, production of phenolic compounds and phenolic acids (including rosmarinic, chlorogenic and caffeic acids) at high level and accumulation of proline through imposing drought stress reduce the adverse effects of stress and increase the medicinal properties of the Nepeta crispa. Also, the effect of drought stress imposing at pre-flowering stage has been greater than its application in the seedling establishment stage. According to the results, it is recommended to impose moderate drought stress at pre-flowering stage to increase biosynthesis of some phytochemical compounds in Nepeta crispa medicinal plants.

Oxidation of exuded phenolic compounds into the culture media, culture medium browning and ceasing growth are the main obstacles in explants establishment during walnut micropropagation. This research was performed as a factorial experiment based on a completely randomized design with three factors including cultivar (Jamal and Chandler), shoot sampling time (May, July and September) and medium conditions (adding activated charcoal to the medium, placing cultures for 24 and 72 h in darkness, sub-culturing thrice per 24 h, twice per 72 h and once after 144 h and the control). Results of the variance analysis of the data related to the establishment of micro-cuttings in culture medium showed that cultivar, sampling time and culture medium conditions as well as their interactions, except the interaction between micro-cuttings and sampling time had significant effects on the Jamal and Chander cultivar micro-cuttings establishment. According to the results of the means comparison, regarding treatments including placement of cultures thrice per 24 hours and adding activated charcoal had a highest level of micro-cuttings establishment in culture medium having significant difference with the other treatments. On the other hand, the results showed a highly significant negative correlation (-0.86) between the micro-cuttings browning index and micro-cuttings establishment. In conclusion, the micro-cuttings establishment of Chandler cultivar had the higher rate compared to Jamal cultivar having statistically significant differences. Finally, it can be stated that collection of micro-cuttings in May and sub-culturing them thrice every 24 hours or adding activated charcoal showed the best results in Chandler and Jamal micro-cuttings establishment.

Existence of environmental abiotic stresses, especially drought stress, is one of the most important problems in arid and semi-arid regions. Drought stress occurs when the plant receives less water than its losses. This research was carried out to investigate the effect of drought stress on morphological traits, proline content and phenolic compounds of rosemary herb in a completely randomized design with 3 replications in Department of Natural Resources, Fars Agricultural and Natural Resources Research Centre. Drought stress was applied at four levels (100%, 75%, 50%, and 25% field capacity). The measured traits were fresh and dry weight of aerial and root organs, leaf area, leaf number, plant length, leaf proline content and phenolic compounds. In this research, rosemary plants were found to have no significant difference in terms of fresh and dry weight of shoot, root fresh weight, shoot length, and normal conditions (FC 100%) in drought stress conditions with 75% field capacity. Also, under drought stress conditions with an intensity of 75% of the field capacity, root length increased to 27.67 centimeters. Root dry weight, leaf area and leaf number decreased significantly under drought stress conditions. In drought stress conditions with a 25% field capacity, the amount of Quercetin (439.04 mg/L), Trans-ferulic acid (72.48 mg/L), Hesperedin (407.62 mg/L), Eugenol (65.36 mg/L), Hesperetin (107.34 mg/L), Rosmarinic acid (1133.34 mg/L) significantly increased. Proline content in drought stress conditions of 25% field capacity was 79.72 μm/g.

To investigate the effect of light quality on germination indices and some vegetative traits of valerian seedlings, a research was conducted as completely randomized design with three replications and light combinations in four levels (R light, 15% B + 85% R , 30% B + 70% R and fluorescent light) were used. The results showed that the highest percentage of germination (63%), germination rate (%41.87), mean daily germination (9.21), germination value (68.81), peak value (7.50) and lowest mean time to germination (2.66) were obtained under R light.The highest dry weight of plumule (0.36 mg/seedling) were obtained under R light and 15%B + 85%R ratio. The highest dry weight of radicle (0.3 mg/seedling) were acquired under30%B + 70% R and 15%B + 85%R ratios. The highest length of plumule and radicle (1.18 and 3.03 cm, respectively) were obtained under R light and 15%B + 85%R ratio. The highest amount of radicle and plumule soluble sugar (63.37 and 72.54 mgg -1 FW, respectively) were acquiredunder R light and 15%B + 85%Rratio. The highest amount of chlorophyll a, b, totalchlorophyll (0.37, 0.47, 0.84 mg g -1 FW, respectively) and carotenoids (0.44 mg g -1 FW) were obtained under 30%B + 70%Rratio, the highest amount of radicle and plumule antioxidant activity (60.09% and 71.04%) under 30%B + 70%R and 15%B + 85%Rratios and the highest amount of radicle and plumule phenolic compounds (4.40 and 8.65 mg g -1 FW, respectively) under 30%B + 70%R and 15%B : 85%Rratios were obtained. The results of this experiment showed that it is possible to improve germination indices and biochemical and vegetative traits of valerian seedlings by the usage of the R and B spectra compare with fluorescent light.To investigate the effect of light quality on germination indices and some vegetative traits of valerian seedlings, a research was conducted as completely randomized design with three replications and light combinations in four levels (R light, 15% B + 85% R , 30% B + 70% R and fluorescent light) were used. The results showed that the highest percentage of germination (63%), germination rate (%41.87), mean daily germination (9.21), germination value (68.81), peak value (7.50) and lowest mean time to germination (2.66) were obtained under R light.The highest dry weight of plumule (0.36 mg/seedling) were obtained under R light and 15%B + 85%R ratio. The highest dry weight of radicle (0.3 mg/seedling) were acquired under30%B + 70% R and 15%B + 85%R ratios. The highest length of plumule and radicle (1.18 and 3.03 cm, respectively) were obtained under R light and 15%B + 85%R ratio. The highest amount of radicle and plumule soluble sugar (63.37 and 72.54 mgg -1 FW, respectively) were acquiredunder R light and 15%B + 85%Rratio. The highest amount of chlorophyll a, b, totalchlorophyll (0.37, 0.47, 0.84 mg g -1 FW, respectively) and carotenoids (0.44 mg g -1 FW) were obtained under 30%B + 70%Rratio, the highest amount of radicle and plumule antioxidant activity (60.09% and 71.04%) under 30%B + 70%R and 15%B + 85%Rratios and the highest amount of radicle and plumule phenolic compounds (4.40 and 8.65 mg g -1 FW, respectively) under 30%B + 70%R and 15%B : 85%Rratios were obtained. The results of this experiment showed that it is possible to improve germination indices and biochemical and vegetative traits of valerian seedlings by the usage of the R and B spectra compare with fluorescent light.

 Background and Objectives :

Salinity is one of the detrimental environmental factors that limit the productivity of crop plants worldwide. Most of the crop plants are sensitive to salinity. Selenium (Se) has not been classified as a plant essential element, but its role as a beneficial element and its ability in amelioration of different environmental stresses has been reported in different plant species. The aim of this study was to investigate the effects of Se on sunflower plants under salt stress conditions.

  Materials and Methods:

 The experiment was conducted as factorial in a completely randomized design by three replications in a hydroponic system with a temperature regime of 25/18°C, photoperiod of 14 h, and relative humidity of 70% in a growth chamber. Seeds were germinated in petri-dishes and then uniform 3-day old seedlings were transferred to 50% Hoagland solution. One week after pretreatment, plants were transferred to 100% Hoagland solution and treated with selenium) sodium selenate; 0, 5, and 10 µM) and salinity (sodium chloride; 50 and 100 mM) for two weeks. Plant's shoots were harvested 15 days after treatments, and frozen in liquid nitrogen until assays.  

Results:

 The results indicated that salinity at both levels significantly increased the MDA as well as free phenol and decreased the flavonoids contents of plants. The anthocyanin, soluble sugars, and total protein contents and the activity of APX increased significantly in response to 50 mM of NaCl, while the proline, tannins, and lignin contents increased, but dry weight and height of shoot decreased significantly in response to 100 mM of NaCl. In non-saline condition, Se application at 5 µM decreased the flavonoids and lignin contents and increased the free phenols, shoot height, and POD activity significantly. Application of Se at 10 µM in non-saline conditions significantly increased the lignin and MDA contents and APX activity. In saline condition with 50 mM of NaCl, Se application at both two levels decreased the soluble sugars and APX activity, and at 10 µM decreased the lignin and increased the tannin contents significantly. In saline condition with 100 mM of NaCl, Se application at both two concentrations considerably decreased the proline, lignin, and tannin contents but increased the APX activity. Furthermore, a reduction in soluble sugars by application of 5 µM of Se was seen in plants that were in saline conditions with 100 mM of NaCl.  

Discussion:

 According to the results of this study, salinity induced oxidative stress in sunflower, especially at 100 mM that was obvious by elevated level of MDA. Even though the Se application in saline condition could induce the notable changes in the phenolic compounds and promoted the activity of APX, it could not inhibit the MDA formation and dry weight falling in plants. Selenium application in non-saline conditions also could not result to the considerable benefits in sunflower plants.

To investigate the effect of polyamines on vegetative and biochemical traits of Crocus sativus L., an experiment was conducted as factorial in a randomized complete block design with three replications in 2015-2016 in Training Field of Tarbiat Modares University with three sizes of corms (3-5, 5-7 and 7-10 g) and five concentrations of polyamines (zero in control, zero in distilled water, spermidine 0.5 and 1 , putrescine 0.5 and 1 ) as the treatments. Results showed that plants treated with putrescine 0.5 and spermidine 1 mM had the highest germination percentage (96.56 percent) and the highest number of lateral sprouts (average number of 8.33), respectively. The length and weight of the leaves were negatively affected by polyamine treatment. The highest chlorophyll content and corm yield were observed in plants treated with Putrescine 0.5 mM and 1 mM, respectively. The content of starch and soluble carbohydrates in dormant corms at the end of growing season were not affected by polyamines significantly; however, total phenolic and flavonoid content in these corms were respectively decreased and increased as a result of applying polyamines. Having no significant effect on stigma dry weight and picrocrocin content, polyamine treatment increased the number of flowers and crocin content in small corms. It is concluded that to obtain better vegetative and biochemical traits of saffron, corms more than 7 g, treated with putrescine, should be used.

Apple fruit color is determined by the amount of pigments in its peel which is directly affected by sunlight. A method for improving apple fruit color is bagging. In present study, the effect of bagging and its optimum removing time was investigated on the amount of peel pigments and other fruit quantitative and qualitative characteristics for Fuji and Granny Smith apples. The experimental treatments were, no bag (control), debagging 7 and 14 days before harvest, and keeping the bag until harvest time. At the end of experiment, the amount of pigments, total soluble solids, titratable acidity, pulp phenol, peel phenol, antioxidants percentage, fruit weight and volume were measured. The results showed that in debagging 7 and 14 days before harvest treatments, the amount of anthocyanin and soluble solids statistically increased as compared with control; however other measured characteristics were significantly reduced in both apple cultivars. The maximum amount of fruit anthocyanin (60.96 mg/g fresh weight) belonged to Fuji cultivar in 14 days treatment and the least amount of fruit anthocyanin (1.64 mg/g fresh weight) belonged to Granny Smith cultivar in zero-day treatment. The highest amount of fruit chlorophyll a (5.09µgr/lit) was observed in control fruit and the lowest amount of fruit chlorophyll a (3.94 µgr/lit) was observed in 14 days treatment. The decrease of chlorophyll amount is a positive characteristic for the Fuji and a negative one for Granny Smith. Therefore, bagging and 14 days before harvest debagging treatment increased the amount of anthocyanin and decreased chlorophyll which resulted in Fuji cultivar better coloring and reducing the green color quality of Granny Smith cultivar.

During the last decade, the synthesis of metal nanoparticles with approximately 1-100 nm have received considerable attention. These nanoparticles have various usages in diffrents fields of sciences and technology. In this study, silver nano-particles were synthesized by the petals and stamens extract of Crocus sativus L. The silver nano-particles were characterized by X-ray Diffraction (XRD), In-frared Spectroscopy (IR), Ultraviolet/Visible Spectroscopy (Uv/Vis) and Transmission electron microscopy (TEM). All techniques were confirmed the synthesis of silver nano-particles. The size of silver nano-particles was calculated by X-ray diffraction (18 nm). The size of nano-particles in TEM images of silver nano-particles was accordance with X-ray diffraction (18 nm). Furthermore, the amount of phenolic compounds and flavonoids of Petals and stamens of Crocus sativus L. were investigated in four solvents with different polarities (Ethanol, Methanol, Chloroform and Ethyl acetate). The results showed that, the ethanol and methanol extracts of Petals are enrich in phenolic and flavonoid compounds, (32.68×10-3 mg/g and 87.6×10-3 mg/g, respectively). Also, the least amount of phenolic and flavonoid compounds of all tissues (Petals and stamens) was extracted in the chloroform extracts. In additions, the antioxidant capacity (IC50) of Petals and stamens were investigated. Methanol extract of all tissues were extracted and the antioxidant capacity were determined as quenching the 2,2-diphenyl 1-picrylhydrazyl (DPPH). The results showed that petals have higher antioxidant capacity than stamens of Crocus sativus L (IC50=5.79 and 14.71 mg/ml, respectively).

This study was aimed to investigate the effects of sowing dates and weed interference on some qualitative and quantitative seed characteristics of chickpea cultivars. The experiment carried out as factorial split plot in randomized complete block design (RCBD) with three replications at research station of Kurdistan University in 2012-13. Sowing dates (autumn, Entezari and spring) and chickpea cultivars (Arman, Azad, Pirouz, ILC482 and Kaka) assigned to main plots as factorial and weed interferences (weeding and non-weeding) as subplots. Results showed that planting dates had significant effects on all studied traits. Weed competition resulted in severe reduction of seed number. In autumn sowing, weed interference reduced seed number by 78%. The reduction of seed numberswere77 and 99% in Entezari and spring sowing dates, respectively. Weed interference increased 100 seed weight as compared to weed free treatment. The highest seed yield observed in Entezari. ILC482 cultivar produced the highest seed yield (132.4 g/m-2). Under weed interference conditions,Kaka was the best grain yield. There was a significant difference between the cultivars for all seed quality traits, but ash, crude fiber and zinc content. The amount of phenolic compounds increased as growth period prolonged. The autumn and Entezari sowing dates were affected not only by cold stress but also encountered with more intense weed interference. Kaka had the highest amount of tannin.

In order to compare the antioxidant capacity, total phenolic content and physico-chemical characteristics of commercial peach cultivars, an experiment based on randomized complete design (RCD) with 6 treatments and 6 replications was conducted. The treatments included six cultivars of white peach, Fig peach, Green peach, Elberta, Redhaven and GHHale collected from Shahd Iran commercial Orchard in Mashhad. The analyzed parameters included fruit and stone weight, length and width fruit, soluble solids, titratable acidity, pH, color variables like as L, a, and b, vitamin C, total phenolics compounds and total antioxidant activity in skin and pulp. The results showed that the heaviest and the lightest fruits in weight were produced by GHHale and Elberta, respectively. Total antioxidant activity and total phenol content varied up to 13-48 mg.ml-1 and 47-209 mg GA.100g-1 fresh weight, respectively. The antioxidant capacity of skin was higher than that of pulp. The best quality fruit in terms of highest vitamin c, total phenolics, total antioxidant activity and soluble solids was produced by green peach. White peach cultivar was suitable in terms of vitamin c, soluble solids and fruit weight, whereas its total phenolics and total antioxidant activity were the lowest. Some color parameters are usable in selecting fruit with high vitamin c and total antioxidant activity.

In order to study the response of coriander medicinal plant to salt stress, two experiments were conducted for germination and vegetative stages. This study was carried out as a factorial experiment based on completely randomized design with three replications. The treatments were salinity at five concentrations including 0, 25, 50, 75 and 100 mM NaCl. Response of coriander seeds germination in first experiment and physiologic characteristics in second experiment were evaluated. Results showed that increase of salinity significantly decreased germination characteristics including germination percentage and rate, radicle and plumule length and dry weigtht (p≤ 0.01). With the increase of salinity, morphological traits like, number of leaves, root and shoot length, fresh and dry weight in shoot and root decreased. Effect of salt stress on amount of chlorophyll, proline, soluble carbohydrates and phenolic compounds was significant (p≤0.01). Mean comparison of treatments showed that with increasing salt stress, amount of proline, carbohydrates and phenolic compounds increased in shoot and root, while concentration of chlorophyll of leaves decreased. Our results support the idea that, accumulation of proline, soluble carbohydrates and phenolic compounds is associated with plant tolerance to salt stress.