جستجوی مقالات مرتبط با کلیدواژه « کلروفیل » در نشریات گروه « زیست شناسی »

St. John's wort (Hypericum perforatum L.) is a medicinal plant that is more than 2000 years old. Drought stress is one of the most limiting environmental factors in the growth and production of plants. Plant symbiosis with mycorrhiza fungi and foliar spraying of essential elements can be one of the most effective solutions to deal with drought stress. This research also aims to evaluate the effect of mycorrhizal fungus and zinc sulfate foliar spraying on some biochemical traits and economic yield in St. John's wort under different irrigation regimes in a split factorial experiment with a basic randomized complete block design in three repetitions carried out during the three cropping years of 2018, 2019 and 2020. The main factor is irrigation regimes at three levels (100, 75 and 50% of irrigation needs); sub-factors were ZnSO4 foliar spraying at three levels (0, 3 and 6 per thousand) and inoculation with an AMF (Funneliformis mosseae) at two levels (inoculated and uninoculated). The results showed that the triple interaction of irrigation regimes + foliar spraying + mycorrhiza in all three years had a significant effect on chlorophyll content, proline, soluble sugars, malondialdehyde and economic yield. Increasing irrigation stress had a reducing effect on chlorophyll content, economic yield, and the relative water content of leaves, but on proline, soluble sugars and malondialdehyde had an increasing effect. At each stress level, the highest economic yield was obtained in the treatment of 6 per thousand foliar spraying + inoculation with mycorrhizal fungi. Generally, foliar spraying of zinc sulfate + mycorrhiza increased the content of chlorophyll, sugar solvents and the relative water content of the leaf, caused the adjustment of the stress conditions and increased the resistance of the plant against drought, and by improving the quantitative and qualitative biochemical traits, it increased the economic yield of the St. John's wort plant.

One of the limitations of keeping, marketing, and exporting capsicum (Capsicum annum L.) is its rapid ripening after harvesting and microbial spoilage, which reduces the quality properties and spoilage of this product. These challenges have been effectively mitigated by using post-harvest techniques. Edible coating treatments can be used after harvesting different fruits. The purpose of this experiment is to use chitosan at four levels (zero, 0.5, 1, and 2%) over time (zero, 7, 14, 21, and 28 days) with four repetitions on the quality after harvesting bell peppers. The variety of California Wonder is a factorial experiment in the form of a completely randomized design. The results showed that a 2% concentration of chitosan prevented weight loss in 28 days. At the end of the experiment, a 2% chitosan treatment compared to the control caused a decrease in TSS by 42.2%. The highest amount of chlorophyll a was observed in the chitosan treatment compared to the control in 28 days. The most significant increase in chlorophyll b in sweet pepper, with a concentration of 2% at zero time, was 113.33% compared to the control. The carotenoid content of sweet pepper showed a significant increase of 97.14% compared to time 0 in the control at the time of 28 days. The results of the average comparison showed that chitosan with a concentration of 0.5, 1, and 2, respectively, in 28 days caused a decrease in ion leakage by 8.56, 9, and 9.57, respectively, compared to the control in 28 days. The results showed that different concentrations of Chitosan and especially the concentration of 2% compared to the control, maintained the quality after harvesting and delayed the aging of bell pepper fruit. According to the results of this research, it is recommended to use this edible coating as an application to increase the shelf life of bell peppers.

Water and soil salinity are one of the serious and developing problems in the world, and a large area of the country's land is also facing this problem. The use of fungal microorganisms in reducing environmental stress such as salinity has become a global solution. In order to evaluate the effect of fungal elicitors on the concentrations of photosynthetic pigments and the amount of proline under salinity stress conditions of Otamaran date palm seedlings, a factorial experiment was conducted in the form of a completely randomized design with 3 levels of salinity and 3 levels of biological elicitors in the horticultural science laboratory. became. The effect of elicitors at 3 levels of fungal consortium (bioactive) (BFC), fungal elicitor with 1000 PPM concentration (EL1), fungal elicitor with 2000 PPM concentration (EL2), the second factor of salinity at three levels (zero, 150 and 300 mM) was evaluated. The results showed that at 300 mM salinity, EL1 mushroom elicitor was able to increase proline compared to other salinity levels. EL2 mushroom elicitor showed more chlorophyll a and total at 300 mM salinity level, and at 150 mM salinity level, the live fungus consortium caused more chlorophyll a. The use of elicitor can be effective in reducing the effects of salinity stress in dates, but the level of stress can determine the effect of each elicitor.

Basil is a medicinal plant as well as a vegetable, and its economic importance is due to its use in health and pharmaceutical industries. Also, moisture stress (water scarcity) is one of the environmental factors leading to a decrease in the yield of any plant. In this study, the effect of moisture stress on the morphological and physiological traits of basil medicinal plant was evaluated as a split plot experiment based on a completely randomized design with three replications in the greenhouse. The results of variance analysis showed a significant difference at the probability level of 1% for the moisture stress effect as well as the genotype effect. The moisture stress × genotype interaction effect was significant for all traits, which means that the genotypes have shown different reactions under moisture stress. The moisture stress caused a significant decrease in most traits while it increased leaf proline. The highest accumulation of proline with an average of 0.0041 mg per gram of fresh weight was related to the Red Rubins basil variety under no-stress conditions and then the Iranian green basil variety with an average of 0.0029 mg per gram of fresh weight under medium moisture stress conditions. The maximum amount of growth characteristics (leaf length, number of leaves, leaf yield and shoot weight) was related to Iranian purple basil cultivar under without moisture stress conditions. Also, the genotype of Iranian green basil can be further investigated in future breeding programs due to its greater tolerance to moisture stress conditions.

This research was evaluated in order to investigate the effect of soil contaminated with heavy elements in Arak region on three sunflower cultivars. The first factor includes: soil contaminated with heavy elements collected from Arak region and its comparison with the uncontaminated control collected from Tafarsh region, and the second factor includes cultivars including: Armaviroski, Alstar, and Ezoflor, common cultivars of sunflower cultivation in Arak region. The effect of contaminated soil on leaf area index traits and leaf area ratio was significant at the level of 1%, but it had no significant effect on other traits. The effect of the cultivar was also significant on the leaf area index at the level of 1%, but it was not significant on the other evaluated indices.. In the investigation of the content of chlorophyll a, the highest amount was assigned to the Alstar cultivar at the rate of 10.54 mg/g fresh weight of leaves, and the lowest amount was assigned to the variety Azoflor at the rate of 10.23 mg/g fresh weight of leaves, which did not have a significant difference. Examining the amount of carotenoid, Allstar, Armaviroski and Azoflor cultivars had 2.53, 2.07 and 1.98 mg per gram of leaf wet weight, respectively, which was significant at the five percent level. Among the cultivars, the most The seed yield was assigned to the Azoflor cultivar at the rate of 3822 kg/ha and the lowest yield was assigned to the Alstar variety at the rate of 2231 kg/ha.

This study was conducted to investigate the effect of auxin and gibberellin on Euphorbia trigona Mill. in a randomized complete block design in 2020, and in greenhouse conditions. One minute pretreatments including auxin regulators NAA, IBA and IAA at a concentration of 500 mg / l and treatments containing GA, IAA, IBA and NAA, 250 mg / l were compared with each other and with control plants. Stems and roots fresh weight, dry weight, dry weight percentage, total photosynthetic pigments content as well as total terpenoids were measured. Fresh and dry weight and the percentage of dry weight of stem did not show sensitivity to the treatments and pretreatments, and the effects were not significant. NAA treatment had the most positive effect on roots fresh and dry weight, although the percentage of root dry weight was not significantly affected by the treatments. The highest significant increase in terpenoid content was observed in NAA treatment and NAA and IBA pretreatments. GA treatment had the most positive effects on the content of each of chlorophylls a and b, total and carotenoid content. In terms of effect on photosynthetic antenna composition, the most positive effects on the ratio of total chlorophyll to carotenoids were observed in GA, NAA, IAA and IAA pretreatments. IAA treatment also showed a significant increase in chlorophyll a to b ratio. The correlation between growth parameters with each other and also the correlation of chlorophyll content with each other and with carotenoids was positive and significant. However, the correlation of terpenoid content with none of the other traits was significant. On the other hand and from an application point of view, based on gas chromatography-mass spectrometry measurements, naphthalene-acetic-acid treatment was effective in severely increasing the content of valuable medicinal compound, bis-2-ethylhexyl phthalate, compared to the control.

The chlorophyll biosynthesis pathway is a main target for genetic modification to change plant photosynthesis and growth rate to support a greater demand for food in the growing world population. In this study, the effect of overexpression of GSA gene one of gene involved in biosynthesis pathway of chlorophyll on physiological condition of tobacco plant was investigated. 5-Aminolevulinate (ALA) is product of GSA gene. ALA is a precursor for all tetrapyrrole, these components have impotent roles in living cell, as pigments, light receptor (Phytochrome), prosthetic group of many different proteins (like cytochromes, hemoglobin, myoglobin, and leghemoglobin) and enzymes (for example Catalase, Ascorbate, Peroxidase and etc.). Nowadays, ALA has received wide attention for its widespread usage in agriculture, forestry and medication. ALA at low concentrations increases photosynthesis, growth, development, yield and productivity, also promoted fruit color appearance and quality and taste of products in treated plants under both normal and stressful conditions. ALA also improves antioxidant features, absorption of nutrient, water use efficiency and osmotic balance in plants.

 In this research, according to bioinformatics studies, MsGSA gene cDNA of Alfalfa (Medicago sativa L. cv. Isfahani) was selected to transfer to Xanthi tobacco (Nicotiana tabacum) plant, the binary expression vector pBI121 which has Kanamycin antibiotic resistance gene for selection in bacteria and plants, cutting sites for SacI and BamHI enzyme, CaMV35S promoter (cauliflower mosaic virus promoter), nos transcription termination sequences and ß-glucuronidase (GUS) reporter gene was used. After constructing the gene construct pBI121-GSA and confirming the transfer of the construct using PCR cloning methods, enzymatic digestion and sequencing were performed, then the corresponding construct was transferred to Agrobacterium tumefaciens strain LB4404 using Agrobacterium with the gene construct. The corresponding gene was transferred to the tobacco plant genome and the transgenic plants were selected on the medium containing kanamycin and the presence of the gene was confirmed by performing PCR in the regenerated plants. The rooted transgenic sprouts were transferred to the soil. The level of GSA gene expression in the resulting transgenic plants was evaluated by real-time PCR, and their growth rate and biochemical content were also evaluated.

 It was observed that the growth of transgenic plants increased significantly depending on the level of GSA gene expression, and the content of ALA (aminolevulinic acid) and chlorophyll a, b and total chlorophyll, which are the products of the corresponding gene expression. The results also showed the content of anthocyanin, flavonoids and phenol of plants have significantly increased in proportion to the increase in GSA gene expression compared to wild type tobacco plants.

 The growth rate as well as the content of chlorophyll a, b, total chlorophyll, ALA, anthocyanin, flavonoids and phenol of transgenic GSA plants is proportional to the increase in the expression of the GSA gene. The results from this study indicate that an increase in transgenic growth rate as well as an increase in the secondary metabolites content in transgenic plants were influenced by GSA transferred gene and an increase in the content of ALA. These results imply that transgenic tobacco plants expressing MsGSA gene had higher resistance potential to stresses than the wild type tobacco plants.

Sports grass is a suitable mixture of premium and resistant varieties of grass that has been widely accepted in many countries of the world for lawn work in parks and sports fields. Considering the role of nanotechnology in the production of plants, it is very important to investigate the effect of nanoparticles on the growth processes of grass. In this research, the effect of iron oxide nanoparticles on some morpho-physiological characteristics of sport grass was investigated. The iron element is very important due to its placement in the electron transport chain and its role in photosynthesis. This research was carried out in a completely randomized design with three replications in fully controlled conditions. Foliar spraying of iron oxide nanoparticles was investigated in three stages with different concentrations (zero, 50, 100, 200, and 400 ppm). The results of variance analysis showed that the effect of iron oxide nanoparticle foliar application on some morphological characteristics such as root length, plant dry weight, and plant density per unit area was significant. The results of the comparison of the average effect of different concentrations of iron oxide nanoparticles on the dry weight of sport grass plants indicated that the concentration of 100 ppm of this nanoparticle accounted for the highest amount of dry weight of the plant with 0.080 grams, also the effect of foliar spraying of this nanoparticle. All physiological traits (chlorophyll a, chlorophyll b, total chlorophyll, carotenoid, anthocyanin, catalase antioxidant enzyme, guaiacol peroxidase antioxidant enzyme, and free radical inhibition percentage) were significant at the 1% level. Based on the results of this research, the application of different concentrations of iron nanoparticles had a favorable effect on the amounts of photosynthetic pigments and antioxidant enzymes, which can be suggested as a suitable elicitor to increase the growth of morphological parameters and increase the quality of physiological parameters in sport grass.

Rosemary is widely used as an ornamental and medicinal plant. Salinity is one of the most important problems for plant production in the world. Knowing the methods that lead to controlling and reducing the effects of salinity in plants is important. The present experiment was conducted as a factorial in a completely randomized design with three replications on three-month-old rosemary plants. The first factor was humic acid treatment (0, 250 and 500 mgL-1) and the second factor was sodium chloride treatment (0, 25, 50 and 75 mM). Based on the obtained results, the minimum length of the main branch (24.41 cm) and the secondary branch (7.68 cm) were obtained in 75 and 50 mM salinity treatments without humic acid, respectively. The highest fresh weight of shoot was in humic acid treatment of 500 mg L-1 + 25 mM salinity, which was not significantly different from humic acid treatment of 250 and 500 mg L-1 without salinity treatment. The dry weight of the branches was influenced by the simple effect of the treatments, so that humic acid 250 mgL-1was effective in increasing the dry weight of the branch, and the highest dry weight of the branch was observed at zero salinity and the lowest dry weight of the branch was observed at 75 mM salinity. The highest content of total chlorophyll and the amount of potassium were obtained in humic acid 500 mg L-1 and the lowest was related to salinity of 75 mM. The amount of proline, ion leakage and sodium percentage were at the maximum in 75 mM salinity without humic acid treatment. According to the obtained results, the use of humic acid 250 and 500 mg L-1 was effective in reducing the negative effect of salinity.

Since, salinity stress threatens food security and sustainable agriculture production, the response of plants to salinity stress has always been one of the most important subjects of physiological and biochemical studies. In order to evaluate the mutant lines in terms of agronomic, physiological and enzymatic traits under salt stress, a factorial experiment was carried out based of a randomized complete block design in three replications using paddy soil and adjusting its salinity in pots. The treatments included four mutant lines (MLST1, MLTH1, MLTH2 and MLTH3) along with two tolerant controls (Deilamani and Nonabukra) and two sensitive controls (IR29 and Sepidrood) at three salinity levels (zero, 4 and 8 dS/m). Results indicated that the highest amount of proline was obtained at a salinity level of 4 dS/m in the MLTH2 mutant, which showed an increase of more than 1.3 times compared to the conditions of no salinity stress. Obtained. The highest and lowest amounts of malondialdehyde (MDA) were respectively at the salinity level of 4 dS/m and no salinity stress related to the MLTH3 genotype. According to the results, the highest level of superoxide dismutase (SOD) enzyme activity was related to the MLTH2 mutant at 4 dS/m salinity and the lowest was related to the MLST1 mutant at 8 dS/m salinity. In the absence of salinity stress, the highest paddy yield was recorded in the salt sensitive cultivar of Sepidroud. By comparison, after applying salinity stress, the lowest yield reduction was obtained in the MLTH2 mutant. In general, based on the biochemical and yield evaluation, the MLTH2 genotype was identified as the best salt tolerant line, which will be to recommend for further research

Salinity stress is one of the most important abiotic stresses in the world that influence the plant growth and productivity. The aim of this study was to investigate the effects of salinity stress (0, 75 and 150 mM) and foliar application of nano TiO2 and ZnO (0, 2 and 4 mg L-1)on the growth and some physiological and biochemical traits of Matricaria chamomilla.

Salinity stress was applied in 3-4 leaf stage of plant under hydroponic conditions. The foliar spraying with nanoparticle was done simultaneously with the initiation of salinity stress. 38 days after second foliar treatment, the plants were harvested to study the desired traits.

The highest flower dry weight was obtained in the NaCl0 × both concentrations of nano ZnO and TiO2. The highest concentration of chlorophyll a (20-50 %) was obtained in NaCl0 × both levels of ZnO and TiO2 nanoparticles and NaCl75mM × 4 mgL-1 nano ZnO. 150 mM salinity increased malondialdehyde and proline content in plant. The results showed that the foliar treatment of TiO2 and ZnO nanoparticles improved elemental content, yield and protein content of the plant under no-salinity, and 75 mM NaCl salinity conditions.

In order to investigate the effect of the biostimulant fertilizer (Companion and Bio-nutrient) and growing medium [soil (control), 75% soil + 25% coco peat and 50% soil + 50% coco peat] on the growth and some physiological traits of Rio Grande tomato, a factorial experiment based on a completely randomized design with three replications was conducted in the research greenhouse of Shahid Madani University of Azarbaijan. The results showed that plant dry weight, yield, fruit volume, soluble solids content, chlorophyll, carotenoids, anthocyanins and titratable acidity were influenced by the interaction effects of experimental treatments. The number of flowers per cluster, number of flower clusters, anthocyanin content and total phenolic content were influenced by the independent effects of biological stimulants. Based on the results, the highest plant dry weight, yield and chlorophyll content were obtained in bio-nutreint fertilizer × 50% coco peat. An increase in fruit volume, soluble solids content and titratable acidity was obtained in 25 and 50% coco peat with both bio-fertilizer applications. Both biofertilizers increased the phenolic and vitamin C content in fruits. The overall results showed that the biostimulant and coco peat medium improved the growth and physiological traits of the plant in this study. The results are an important step in reducing the use of chemical fertilizers in tomato production and replacing them with environmentally friendly compounds.

Zinnia (Zinnia elegans) is an annual and widely used ornamental plant. Considering the importance of the growing medium in the production of ornamental plants, this study was conducted to investigate the effect of wood waste compost and humic acid on the morphological and physiological characteristics of Zinnia. Wood waste compost (0, 25, 50, 75 and 100% instead of peat moss in the control growth medium) along with humic acid (0, 250 and 500 mg L-1) were used. Peat moss, perlite and garden soil (1:1:1) were used as the control substrate. In this research, plant height, number and surface of leaves, fresh and dry weight of plants, fresh and dry weight of roots, flower diameter, chlorophyll, nitrogen, phosphorus and potassium of leaves were investigated. According to the obtained results, the highest amount of plant leaf area was obtained in 50% compost with 500 mg L-1 of humic acid and the highest number of leaves were obtained in 75% compost with 500 mg L-1 of humic acid. The largest flower diameter (76.2 mm) was recorded in 100% compost. The amount of chlorophyll a and b in 100% compost combined with humic acid of 500 mg L-1 was at the highest level. The highest amount of nitrogen (0.75%) was recorded in 100% compost. The application of humic acid 250 mg L-1 caused a significant increase in leaf potassium. In general, the results showed that the application of compost in amounts of 50 to 100 percent and humic acid of 250 and 500 mg L-1 was effective on flower diameter, plant height, number of leaves, chlorophyll, and the increase of nitrogen and potassium elements in Zinnia leaves.

Selenium with antioxidant properties, has positive effects on growth and development of biological activities of many plants but its excessive levels in soil causes physiological problems. This study was conducted to investigate the effect of selenium (bulk) and nanoselenium on some of physiological and biochemical of Vasha, in a completely randomized experiment. Selenium in form of sodium selenate was applied in nutrient solution at concentrations (0, 2.5, 5 and 10 mg L–1) and nanoselenium at concentrations (0, 2.5, 5, 10 and 20 mg L–1). The results showed that application of both bulk and nano-Se treatments significantly increased plant growth parameters (i.e. length of roots and shoot, the root and shoot fresh and dry weights), as well as the content of photosynthetic pigment, total flavonoids, total phenol, anthocyanin and carbohydrate content by 2.5 mg L–1 and 10 mg L– 1 of selenium and nanoselenium respectively. Moreover, the abovementioned concentrations were associated with a significant increase in plant antioxidant activity. All treatments reduced malondialdehyde. The most increase in chlorophyll a was observed at a concentration of 10 mg L-1 nano-Se, which decreased with increasing selenium concentration compared to the control treatment. The results showed that the positive effect of selenium on the growth and increase of phenolic compounds depends on the type and concentration of selenium application.

Dunaliella salina is a carotenoid-producing microalgae that is important for its extraordinary ability to accumulate ß-carotene. Therefore, an experiment was performed to investigate the effect of different concentrations of gibberellic acid on growth, accumulation of chlorophyll pigments, carotenoid content, and dry biomass of D. salina in f/2 medium. Experimental treatments included different concentrations of gibberellic acid (GA3): 0 (control), 0.5, 5, 10 and 20 mg/L. The measured traits in this experiment included growth rate and doubling time, chlorophyll a, chlorophyll b, total chlorophyll, total carotenoid, dry biomass, total lipid content, and endogenous gibberellic acid. The analysis of variance showed that the effect of different concentrations of gibberellic acid on all studied traits in D. salina was significant at the statistical level ρ)≤ 0.05). Gibberellic acid (GA3) at a concentration of 10 mg/l increased growth rate, chlorophyll a and b content, total chlorophyll content, dry biomass and total lipid content in the studied microalgae. While the highest amount of total carotenoid accumulation was recorded for 5 mg/L GA3 treatment. According to our findings, it is suggested that 5 mg/L GA3 concentration can be effective, if the purpose of cultivating this microalgae species is to produce carotenoid, but if the aim of production are dry biomass and total lipid content, the use of 10 mg/L GA3 concentration will stimulate and increase the production of microalgae total lipid and dry biomass.

Yaghooti grape is the earliest ripening grape in Iran and has advantages such as good taste and high heat and drought resistance; but it has highly cluster density. Physiological alterations of Yaghooti grape in three growth stages, as well as the amount of accumulation of some physiological substances, under the three hormones gibberellic acid, indole-3-acetic acid, and abscisic acid. Abscisic acid hormone had the most positive effect on total chlorophyll and carotenoid levels. The average amount of total chlorophyll was equal to (25.51), (18.76) and (26.16) mg/ml in the pre-flowering, flowering, and post-flowering stages, respectively. Under three hormones, the protein level is greatly reduced by 70%, Gibberellin treatment in the third stage of cluster development caused a 26% increase in carbohydrate level. The guaiacol peroxidase increased under indole acetic acid, but other hormonal treatments decreased the amount of this enzyme in Yaghooti grapes. The biggest reduction was related to gibberellin treatment with nearly 80% of the control sample in the first and second stage of cluster development and 55% in the third stage. The amount of ascorbate peroxidase enzyme was accompanied by an upward trend under influence of abscisic acid. Also, all three hormones almost caused a decrease in catalase enzyme activity in all three developmental stages. Indole acetic acid increased the activity of polyphenol oxidase enzyme during stages. Gibberellin, apart from slightly increasing the activity of ascorbate peroxidase enzyme during flowering, strongly reduced the activity of three other enzymes during all stages.

Silicon (Si) is regarded as one of the beneficial nutrient elements for most plants. Si increases the yield and crop quality and plays an important role in plant resistance against the environmental stresses. With science development and nanoparticle production, their application in different industry such as agriculture has gained much atlention. This research was conducted in a factorial experiment based on a completely randomized design with 3 replications and 4 plants in each replicate. Foliar spray and root application were carried out using 20, 40, 60 and 80 mg L-1 micro- and nano-SiO2 at two growth stages (the first stage in 4-5 leaves of plants and second stage two weeks after first stage). Physiological characteristics including leaf relative water content, leaf and fruit carbohydrate, leaf and fruit nitrate, chlorophyll (a, b, total) and carotenoied and activity of catalase and peroxidase were measured. The results showed that applied treatments did not have any significant effect on leaf relative water content and fruit nitrate, but application of silicon increased significantly leaf and fruit carbohydrate as well as leaf nitrate. Silicon, particularly at the nanoscale, led to a significant increase of chlorophyll a, b and total, but had no significant effect on the amount of carotenoid. Application of silicon led to a significant increase of catalase activity, but had no significant effect on the activity of peroxidase. Totally, application of nano-silicon in comparison with the control and mico-silicon had the positive effects on physiological characteristics of strawberry plants. Overall, in hydroponic culture and greenhouse production of strawberries, according to the results of this research, the application of 60 mg L-1 nano-SiO2 through the root apply method is recommended.

In this study, the effect of various levels of salinity on Dracocephalum kotschyi Boiss. (Fereidunshahr population) and the role of melatonin in improving photosynthesis and the acquisition of salt tolerance was investigated using two independent experiments. In the first experiment, the effect of different concentrations of sodium chloride (0, 25, 50, 75 and 100 mM) on the growth and photosynthetic traits of 60-day-old plants was evaluated. The results showed that with increasing salt concentration the tolerance index and the amount of photosynthetic pigments, Fv/Fm, and stomatal conductance decreased, but the level of lipid peroxidation and catalase activity increased in the leaves. In the second experiment, the effect of root pretreatment with 100 µM melatonin was investigated on salt tolerance (100 mM sodium chloride) of D. kotschyi seedlings. The results showed that pretreatment with melatonin increased fresh and dry weight of aerial part, chlorophyll a and b, total chlorophyll and carotenoids, Fv/Fm, stomatal conductance and relative water content in leaves under salt stress. The positive effect of melatonin on photosynthetic parameters was closely related to its role in increasing ascorbate peroxidase enzyme activity, reducing malondialdehyde content and improving Na+, K+ and Ca2+ homeostasis in leaves, and these effects were weakened by the application of p-CPA as an inhibitor of melatonin synthesis. Based on these results, the application of external melatonin, probably by affecting the endogenous melatonin synthesis in plants, is able to moderate the osmotic stress, ionic toxicity and oxidative stress caused by salinity in D. kotschyi plants, and it is possible that melatonin treatment can use to improve phosynthesis and the level of plant's tolerance to salinity.

In most of the wheat cultivated areas in the world, drought stress during the reproductive stages leads to a significant reduction in grain yield. Therefore, considering the arid and semi-arid climate of this country and the increased population ahead, it is necessary to identify cultivars tolerant to drought and related traits. On this basis, the present study was conducted as a randomized complete block design with three replications in the research farm of the Faculty of Agriculture, Shahid Bahonar University of Kerman in 2016-2017 cropping year. Experimental treatments included 28 bread wheat cultivars which were cultivated in two different environments (normal conditions and drought stress). GGE bipolates are one of the most accurate and efficient multivariate models. The GT type of this biplot deals with the relationships between traits in genotypes. Based on the results, the vectors in biplot showed that there was a strong and positive correlation between physiological traits such as chlorophyll pigments concentration, carotenoids, chlorophyll index, and relative water content with yield in both normal irrigation and terminal drought conditions. Under stress conditions, the concentration of elements had a negative correlation with yield, but this was with normal irrigation, whereas only microelements had a negative correlation. According to the biplot diagram, Roshan, Pishgam, Zagros, Omid, and Baran genotypes were introduced as the best genotypes for some or all of the traits under drought stress. On the other hand, evaluation of tolerance of genotypes with tolerance indices also showed that MP, GMP and STI indices had a positive and significant correlation with grain yield and therefore Alvand and Omid were identified as tolerant and sensitive genotypes, respectively. According to the present results, G×T biplot and tolerance indices (MP, GMP, and STI) can be a good way to evaluate the superiority of traits and identify tolerant genotypes, and by this way, superior genotypes with high production capacity and desirable traits can be used in drought tolerance breeding programs. Also, photosynthetic pigments and element concentrations can be a good criterion for improving grain yield, especially under stress conditions.

Since the synthesis of some chemical compounds is difficult and expensive, it is necessary to find ways to increase their production in plants. One of these materials is color compounds. Chlorophyll, as a natural pigment, plays an important role in the green appearance of plants. This color is used in food, cosmetics, etc industries.

The purpose of this project is investigation of different methods of chlorophyll extraction for more chlorophyll content in alfalfa plants

To carry out this project, alfalfa cultivated and then the aerial part was harvested for biochemical analysis and kept at different temperatures (-20 and 4). chlorophyll was extracted using acetone and ethanol solvents by grinding method and methanol, DMSO and DMF solvents by soaking method and then its amount was measured by spectrophotometer at the respective wavelengths.

Based on the obtained results, it can be said that acetone solvent with high ability and producing more extractable chlorophyll concentration than other solvents was chosen as the appropriate solvent. Also, samples kept at minus 20 temperature showed more chlorophyll due to less possibility of destruction.

maintaining of the aerial part of the plant at -20 keeps more chlorophyll than at 4°C and extracting chlorophyll by grinding in acetone has a better performance compared to other solvents.