فهرست مطالب مهدی برادران فیروزآبادی

Seed aging reduces the quality and quantity of agricultural production by reducing quality, viability, and irreversible seed vigor over time. Researchers are increasingly interested in seed aging, which is a serious problem in agriculture. To reduce damages caused during aging, various pretreatment techniques have been studied, including chemical compounds, growth regulators, and antioxidants. Sowing seeds in low osmotic potential osmotic solution is one method of slowing seed aging by osmopriming them. To reduce the negative effects of seed aging, biostimulants such as seaweed extract are used. In order to investigate the effect of seaweed extract on the quantitative and qualitative yield of soybean, an experiment was conducted in the two years of 2018 and 2019 in the research farm of Shahrood University of Technology.

The experimental treatments involved the acceleration of aging in two groups: normal seeds and aged seeds. Additionally, seaweed extract was applied at four different levels: control, seed pre-treatment with a seaweed extract concentration of 0.3%, foliar spraying with a seaweed extract concentration of 0.3%, and a combination of seed pre-treatment and foliar spraying with a seaweed extract concentration of 0.3%. This was conducted as a factorial experiment, employing a randomized complete block design with three replications. A sample of DPX was collected from the Mazandaran Agricultural Research Center. A controlled storage room was used to maintain the seeds at a temperature of 14-17°C and relative humidity of 30-40%. The seeds were harvested the same year as the experiment. In order to apply accelerated aging, the seeds were kept for 72 hours at a temperature of 41°C and relative humidity of 95%. Foliar spraying was done at the beginning of flowering (R1).

 The results showed that accelerated aging decreased the mean daily emergence and germination index by 61.39 and 42.08% compared to the control. The pretreatment of soybean seeds made them more responsive to external stimuli and counteracted stress conditions before they emerged as seedlings. When the seeds were pretreated with seaweed extract, the mean daily emergence and seed germination index increased. The weight of one hundred seeds and the number of pods per plant decreased by 11.64 and 11.38% compared to the control. The combined application of seed pretreatment and foliar spraying in normal and aging conditions had the highest hundred seed weight and the number of pods per plant. In protein-rich crops, seaweed biostimulants can increase protein production. Pretreatment of normal and aged seeds with seaweed extract increased by 1.48 and 1.61 percent of seed protein. In order to improve soybean germination percentage, protein, and seed yield, ellagic acid and seaweed extract should be used individually or combined. Accelerated aging caused a 32.69% decrease in seed yield compared to normal conditions. The combined application of pre-treatment and foliar spraying of seaweed extract had the highest seed yield, which increased by 87.85% compared to the control. Seed aging likely caused a reduction of seed yield by reducing the mean daily emergence, leaf area index, and 100-seed weight. There are three main characteristics (mean daily seedling field emergence, the number of pods per plant, and 100-seed weight) that can explain 85.96% of seed yield variability based on the coefficient of explanation. An analysis of causal connections between seed yield and 100-seed weight showed that seed protein content directly affects seed yield. By increasing the number of pods per plant and the weight of 100 seed, soybean seeds yield may be enhanced by using seaweed extract.

With its powerful antioxidant properties and anti-aging properties, seaweed extract minimizes the effects of aging on aged seeds. Finally, within the scope of the research, it is possible to suggest the use of pre-treatment and foliar spraying with seaweed extract to increase seed yield and protein percentage in normal and aged soybean seeds.

Zinc (Zn) plays an important role in plant growth and tolerance to stress and increasing their yield, but it has been reported that zinc nanoparticles have a better role on improving the growth of plants under water stress conditions. One of the factors limiting the growth of sorghum forage plant is water stress. Studies have shown that zinc nanoparticles have a positive impact on plants response to water shortage conditions through improving photosynthesis and enzymaticactivity. Therefore, this study was conducted to investigate the effect of foliar application of nanosized and non-nano zinc oxide on some physiological and forage yield of three sorghum (Sorghum bicolor L.) cultivars under water deficit condition.

This study was performed at the research farm of Shahrood University of Technology in the growing season of 2018-19. The experiment was arranged as split plot factorial based on randomized complete block design with three replications. Water deficit stress treatment in two levels of 10 and 20 days irrigation interval were assigned as main plots and sub plots were the combination of the two factors; sorghum cultivars at three levels: Eresk, Speedfeed and Pegah, and foliar application of zinc in three levels of control, micro and nano-particles forms at concentration of 2 gr l.-1. Foliage spraying of Zinc was performed before flowering stage of sorghum. Sampling and measuring of sorghum pigments, leaf protein, leaf zinc contents and proline were done at flowering stage. Wet and dry forage yield of sorghum was measured at the end of growing season on the 2 squares meter in each plot. All data collected were subjected of analysis of variance (ANOVA) using MSTATC software. Significant differences between means refer to the probability level of 0.05 by LSD test.

The results showed that by increasing the irrigation interval from 10 to 20 days, chlorophyll a, chlorophyll b, carotenoids, leaf protein, leaf zinc content, fresh and dry forage yield decreased significantly. The results indicated that the minimum fresh forage yield (61.48 ton/ha) and dry forage yield (12.03 ton/ha) was observed with non-application of zinc in irrigation interval of 20 days. Water deficit stress causes damage to photosynthesis pigments, stomatal conductance and finally the growth and yield of plants. The results showed that application of zinc in nano or conventional form causes a significant increase in chlorophyll a, chlorophyll b, carotenoids, proline, leaf protein, zinc content, fresh and dry forage yield under stress conditions. The highest fresh and dry forage yield were observed at the rate of 97.4 and 18.8 ton.ha-1 respectively in irrigation interval of 10 days treatment by application of ZnO nano particles. Also, the results showed that, foliar application of zinc in nano and conventional form increased fresh forage yield of sorghum by 37.58 and 32.49 percent compared with control in water deficit stress condition respectively. This can be due to the role of ZnO nano particles that can enhance the rate of photosynthesis by improving gas exchange, chlorophyll fluorescence, carbonic anhydrase activity, and enhanced proline content in plants. Results also showed that in the most of physiological and yield traits and forage yield the local Ersek cultivar was better significantly than Speed ​​Feed and Pegah cultivars.

The foliar application of ZnO conventional and nano particles significantly mitigated water deficit stress and enhanced photosynthesis pigments, proline, leaf protein and zinc contents as well as improved the fresh and dry yield of sorghum.

Background and objectivesSoybean is considered one of the most important oil and protein plants in Iran and the world. Considering the importance of soybean yield and identifying traits effective in increasing it, this research was conducted with the aim of investigating the relationship between seed yield and agronomic and physiological traits of soybean and determining the traits that have a greater effect on seed yield under normal and accelerated aging conditions.Materials and methodsThe present experiment was conducted in the research farm of the Faculty of Agriculture of Shahrood University of Technology during 2017-2018 and 2019-2020, in a factorial experiment in the form of randomized complete blocks in three replications on Katol variety. The treatments included accelerated aging in two levels (normal seeds and aged seeds) and seaweed extract in three levels (control, pre-treatment and foliar spraying). The seeds used were obtained from the research center for agriculture and natural resources of Mazandaran and the seeds were harvested in the same year and until the time of testing, they were kept in a controlled warehouse with a cooling system at a temperature range of 14 to 17°C and a relative humidity of 30 to 40%. In order to apply aging, the seeds were placed for 72 hours at a temperature of 41°C and a relative humidity of 95%.ResultsThe results showed that in plants obtained from normal seeds, 84.81% of the changes in seed yield are justified by the number of pod per plant, the number of seed per pod and the 100 seed weight. In these plants, the 100 seed weight and then the number of pods per plant had the most direct and positive effect. The most direct and positive effect was attributed to the 100 seed weight, followed by the number of pods per plant. The trait of the number of seed per pod affected the seed yield both directly and indirectly through the effect on the 100 seed weight. Causality analysis in the plants obtained from aged seeds showed that the characteristics of final emergence percentage, membrane stability index, leaf area index, anthocyanin, hydrogen peroxide, superoxide radical, number of pods per plant and 100 seed weight were entered into the model as main variables and 91.33% of the changes are explained by these eight traits. Seed pre-treatment with seaweed extract increased seed yield by increasing the percentage of final emergence of the field, the 100 seed weight and the amount of glutathione in the leaves of the plant. Foliar spraying of seaweed extract caused a significant increase in seed yield through increasing the weight of 100 seed weight and membrane stability index.Conclusion The characteristics of 100 seed weight and number of pods per plant in plants obtained from normal and aged soybean seeds can be considered as selection criteria for improving and improving yield due to their direct and increasing effect on seed yield.

In order to investigate the effect of ellagic acid on the growth indices and leaf aging process in soybean, an experiment was conducted during the two years of 2018 and 2019 in the research farm of Shahrood University of Technology's Faculty of Agriculture. The experiment was carried out factorial in the form of a randomized complete block design in three replications. The experimental treatments include the initial seed quality at two levels (normal seeds and aged seeds) and the application of ellagic acid at four levels (control, priming, foliar spraying and combined application of priming and foliar spraying with a concentration of 50 mg/L). The results showed that accelerated aging decreased the amount of chlorophyll, carotenoid, plant height, leaf and stem dry weight, oil percentage and seed yield compared to the control. The use of ellagic acid in the form of priming, foliar spraying and their combination in this study increased the percentage of oil by 0.23, 0.24 and 0.29%, respectively, compared to the control. Priming, foliar spraying and the combined application of priming and foliar spraying with ellagic acid improved the grain yield by 23.59, 23.23 and 55.48%, respectively. The use of ellagic acid as seed priming and foliar spraying better than other levels. Finally, it is recommended to use this material as a priming to increase the percentage of oil and yield of soybean.

This experiment was conducted to investigate the effect of seaweed fertilizer on the improvement of physiological traits of soybeans in the research field of Shahrood University of Technology Faculty of Agriculture during two crop years, 2018–2019 and 2019–2020. The experiment was carried out factorially in the form of a randomized complete block design in three replications. The experimental factors included accelerated aging in two levels (control seeds and aged seeds) and seaweed fertilizer in three levels (control: no treatment, seed pretreatment and foliar spraying with a concentration of 0.3% seaweed fertilizer). Results showed that accelerated aging in the first and second years of the experiment caused a decrease of 15.11 and 13.33% in the amount of chlorophyll a in leaves of plants obtained from these seeds. In both years, the foliar application of seaweed fertilizer in normal and aging conditions caused a significant increase in the amount of chlorophyll a to a significant level. Accelerated aging in seeds caused an increase of 35.13, 12.46 and 22.22 percent of carotenoid, flavonoid and anthocyanin in the leaves of plants obtained from these seeds, respectively. Accelerated aging decreased by 0.86%, 0.90% and 33.18% of seed oil, protein and yield. The maximum levels of oil and protein were 19.74% and 38.31%, respectively, which belonged to foliar spraying and seed pretreatment treatments. Using seaweed fertilizer as seed pretreatment and foliar spraying increased yield by 36.49% and 21.67%, respectively, compared to the control. Finally, pre-treatment of seeds with seaweed fertilizer can be suggested to improve the effects of seed aging and increase yield in the soybeans.

Food security is one of the basic needs of any society. Studies have been conducted on the foliar application of elements, especially silicon, calcium, and potassium, to reduce the adverse environmental effects on the physico-mechanical properties of cereals and improve their growth and development in order to maintain food security. Lodging, which is caused by a decrease in the mechanical properties of the plant stem's flexural strength, is characterized by bending or fracture that changes the angle of the grain stem from the vertical position. Due to the important factors involved, an important aspect of performance is directly and indirectly related to the occurrence of fungal diseases and nutrient-related issues affecting the physico-mechanical properties of the plant, such as flexural strength. The efficacy of silicon, calcium, and potassium in addressing these concerns is notable.

This research was conducted at the research farm of the Faculty of Agriculture, Shahroud University of Technology, located in Bastam. The seeds of the Reyhan cultivar, a high-yielding and early spring-type barley plant suitable for regions with mild winters and short springs, were used in this study. Planting operations followed agricultural principles, and irrigation was carried out using atmospheric and ridge methods. The first irrigation took place after planting, and subsequent irrigations were performed aeight-day intervals. Harvesting was done manually at the end of the growing period, specifically 115 days after planting.The experiment followed a factorial design and utilized a randomized complete block design with three replications. On July 11 (115 days after planting), a harvest sample measuring 50 cm2 was taken from each experimental plot, accounting for the margins, to determine the yield.For the barley stem bending test, a three-point bending test was conducted using a material testing machine. The probe applied a loading speed of 5 mm.min-1. A specially designed jaw was used for the barley stem cutting test, taking into consideration the characteristics of the barley plant. The incision test was performed on the second median, and the loading speed was set at 20 mm.min-1.

The main axial stem serves as a storage organ, supporting the filling grains through stock re-transference. A desirable trait is having a higher dry weight in the stem. Among the treatments, foliar application of 6 mM calcium chloride, along with sodium silicate at all three levels and spraying with 12 mM silicon at concentrations of 150 and 300 mg.L-1, showed statistically superior results.Stem diameter is an important attribute related to plant strength, stability, resistance to lodging, and certain fungal diseases. The control plants had a stem diameter of 2.63 mm, which significantly improved with the treatment compounds. Barley stem wall thickness increased significantly with both 150 and 300 mg.L-1 levels of calcium chloride, combined with all three levels of sodium silicate spraying. These factors play a role in determining the ultimate photosynthetic destination, as well as the efficiency and economic production of the target seed cultivar or crop.The results indicated a significant increase in grain yield when simultaneously applying 10 mg.kg-1 silicon with 6 mM calcium chloride, showing a 65% improvement compared to the control. Treatment with three potassium sulfate variations, combined with either 6 or 12 mM calcium chloride, or 12 mM calcium chloride alone, enhanced the flexural strength of the stem by 75%, 60%, and 62%, respectively. Among the treatment compounds studied, the shear strength of barley stems ranged from 2.63 MPa to 5.43 MPa. Plants treated with sodium silicate at concentrations of both 150 and 30 ml.L-1, in conjunction with 6 mM calcium chloride foliar application, exhibited higher shear strength compared to other treatments.

This study demonstrated the tripartite effect of the treatments. The treatment composition derived from a surface area of 300 ml.L-1 of sodium, combined with 6 and 12 mM calcium chloride without potassium sulfate, had the greatest impact on flexural strength and stem diameter.

Ellagic acid is a natural polyphenol compound, and different concentrations and ways of using it cause different reactions in plants. This research was conducted to investigate the effect of ellagic acid and seed quality on the phenological stages and yield of soybeans.

The factorial experiment was designed and implemented in a randomized complete block design in three replications in the agricultural years of 2019 and 2020 in the research farm of the Faculty of Agriculture, Shahrood University of Technology. In this experiment, the initial quality of the seed was considered in two levels (normal seed and aged seed) and ellagic acid in four levels (zero, priming, foliar spraying and combined application of priming and foliar spraying with a concentration of 50 mg/liter). Accelerated aging test was used to apply aging and for this purpose, the seeds were kept for 72 hours at a temperature of 41°C and a relative humidity of 95%. Seed priming was done with a concentration of 50 mg/liter of ellagic acid, following the principles of seed aeration for six hours. The spraying treatment was done early in the morning and at the beginning of flowering (R1) and in favorable environmental conditions.

The results showed that accelerated aging in the first and second year of the experiment, respectively, caused a decrease in the final emergence percentage of seedling in the field by 30.93 and 29.93% compared to the control. In the first and second year, the normal seed priming test with ellagic acid increased the final emergence percentage of field by 16.33 and 12.67 percent, respectively. The final emergence percentage of the field in the first and second year of the experiment in aged seeds that were primed with ellagic acid was improved by 14.33 and 8.33%, respectively, compared to the control. Accelerated aging caused a significant decrease in germination rate by 37.66% compared to the control. The final emergemce percentage of seeds that were primed with ellagic acid increased by 18.75% compared to the non-application of this substance. In this experiment, accelerated aging caused a delay in the occurrence of phenological traits in soybean plants. The use of ellagic acid as priming and the combined use of priming and spraying could increase the rate of occurrence of phenological traits to a significant level. Applying accelerated aging in the first and second year of the experiment caused a decrease of 25.85 and 28.78 percent of seed yield, respectively. The use of ellagic acid in the form of priming, foliar spraying and the combined use of priming and foliar spraying increased the seed yield by 23.59, 23.23 and 55.48%, respectively, compared to the control.

The use of ellagic acid as priming and the combination of priming and spraying can be suggested to accelerate the occurrence of phenological traits in soybeans. In this study, the application of ellagic acid as priming worked better than foliar spraying. It is recommended to use priming and ellagic acid solution to improve soybean yield under normal and aging conditions.

Ellagic acid is a natural polyphenol compound that has strong antioxidant properties and reduces the effects of various stresses in plants. In order to investigate the effect of ellagic acid on protein percentage and soybean yield, an experiment was conducted in the two crop years of 2018 and 2019 in the research farm of Shahrood University of Technology. Treatments include accelerated aging on two levels of normal seed and aged seed and the application of ellagic acid on four levels (control, seed pre-treatment, foliar spraying and the combination of seed pre-treatment and foliar spraying with ellagic acid with a concentration of 50 mg/L) in the form of a factorial experiment with a basic design of randomized complete blocks in three replications. The number of pods per plant, the number of seeds per pod and the 100 seed weight per plant obtained from aged seeds decreased by 11.64, 4.16, and 13.13%, respectively, compared to the control. The combined use of seed pretreatment and foliar spraying of ellagic acid in normal and aging conditions caused a significant increase of 10.00 and 11.30% in the number of seeds in the pod compared to the non-application of this substance in these conditions. The combined use of seed pretreatment and foliar spraying of ellagic acid caused an increase of 20.89 and 51.93% in the weight of 100 seed and seed yield, respectively, compared to the control. The application of ellagic acid in normal conditions did not show any effect on the protein percentage, while the use of this substance in aging conditions by the form of seed pretreatment, foliar spraying and the combined use of seed pretreatment and foliar spraying, led to an increase of 0.88, 0.40, and 0.86 percent of protein, respectively. It is possible to suggest the combined use of pretreatment and foliar spraying with ellagic acid to increase seed yield and protein percentage in plants obtained from normal and aged soybean seeds.

Seed aging is a phenomenon that occurs during the life of any seed. Changes that occur during aging affect seed quality. Through the process of aging, seed vigor is the first trait of the seed quality that decreases, followed by a decrease in germination capacity, seedling growth and establishment. Hence, one way to stimulate germination and increase the establishment of seedlings from aging seeds is seed pre-treatment using different materials such as brown seaweed extract. The aim of this study was to investigate the effect of seaweed extract pretreatment on germination traits and heterotrophic growth of un-aged and aged soybean seeds.

The experiment was designed and implemented at a laboratory in the faculty of agriculture of Shahrood University of Technology in 2019. Treatments included seed aging at two levels (un-aged seeds and aged seeds) and pretreatment with seaweed extract at seven levels (zero, distilled water, 0.1, 0.2, 0.3, 0.4 and 0.5 %). The experiment was carried out as a factorial in a completely randomized design (CRD) with three replications in the germinator environment. The seeds were aged by being placed at 41°C and 95% relative humidity for 72 hours. Seed pretreatment seaweed extract was done for 6 hours in accordance with the principles of seed aeration.

Aging reduced germination percentage and germination rate, allometric growth ratio, seedling length vigor index, seed reserves use efficiency and seed vigor index. Malondialdehyde content and electrical conductivity of aged seeds were 37.68% and 38.32% higher than un-aged seeds respectively. Seed pretreatment with 0.1, 0.2 and 0.3% of seaweed extract significantly increased germination rate, germination index and seed reserves use efficiency. Slicing interactions of aging and seaweed extract showed that seed pretreatment with 0.1, 0.2 and 0.3% of seaweed extract significantly increased germination rate and germination index in un-age seeds. Pretreatment of aged seeds with 0.1, 0.2 and 0.3% seaweed extract increased germination percentage by 8.73%, 8% and 15% compared to the control (aged seeds without pretreatment), respectively. The use of distilled water and all levels of seaweed extract in this study increased the seed vigor index and decreased the electrical conductivity. The amount of malondialdehyde in aged seeds was reduced by using all levels of seaweed extract. The use of 0.2, 0.3, 0.4 and 0.5% of the extract increased the amount of seed reserves use rate and fraction of seed reserves mobilization in aged seeds.

Finally, in the scope of this research between the concentrations used, the concentration of 0.3% seaweed extract was better than the others. It can also be suggested that the use of seaweed extract as a seed pretreatment improves the effects of seed aging on soybeans.

1-The effect of pretreatment with seaweed extract with concentrations of 0.1 to 0.5% on un-aged and aged soybean seeds was investigated for the first time.
2-Using a concentration of 0.3% seaweed extract for the pretreatment of soybean seeds was introduced as the best concentration.
3- Seaweed extract was introduced as an important antioxidant to improve physiological traits in soybean seeds.

Soybean seeds are sensitive to storage due to their high oil content and they aged quickly. Aging of seeds leads to a decrease in the percentage and speed of germination and ultimately to a decrease in seed yield. Although the aging rate can be reduced with proper storage methods, the application of some treatments on the aged seeds or spraying some substances on the plants obtained from these seeds can be effective in improving the seed yield. The use of anti-aging substances such as seaweed extract in plants can act as antioxidants and reduce the effects of aging.
 
In order to evaluate the phenological stages and yield of soybean, an experiment was carried out in the research farm of Shahrood University of Technology during 2019 and 2020 in three replications. The treatments include the initial seed quality in two levels (normal seeds and aged seeds) and seaweed extract (Ascophyllum nodosum) in four levels (control, priming, foliar spraying and combined application of priming and foliar spraying with a concentration of 0.3%). The experiment was carried out as a factorial in the form of a basic design of randomized complete blocks.
In this research, applying accelerated aging caused a significant increase in phenological traits in soybean plants. The use of seaweed extract as a priming and the combined use of priming and foliar spraying could increase the rate of occurrence of phenological traits to a significant level. The seed yield in plants obtained from aged seeds was 32.69% less than that of control plants. The use of seaweed extract as priming, foliar spraying and the combined use of priming and foliar spraying increase the seed yield by 43.54, 15.69 and 87.85 percent, respectively. Aging caused a significant decrease of 23.50 and 25.33 percent of final emergence percentage. Pretreatment of normal and aged seeds with seaweed extract in the first year increased this trait by 16.33 and 7.33% compared to the absence of seaweed extract. In the second year of the experiment, the application of seaweed extract resulted in a 12.67% increase in seedling growth under normal conditions, and an 8.33% increase was recorded with the application of seaweed extract under aging conditions.
 
In this study, the application of seaweed extract as seed priming better than foliar spraying. It is possible to recommend priming and the combination of priming and foliar spraying with seaweed extract to accelerate the occurrence of phenological traits in soybeans. The combined use of priming and foliar spraying of seaweed extract is recommended to improve the performance of soybeans in normal and aged conditions.

Buckwheat (Fagopyrum esculentum Moench) is an annual plant of the Polyganales family, native to the United States of America. This plant is one of the most important medicinal plants. However, Drought stress as a limiter has a great effect on reducing its yield. Therefore, this study aimed to investigate the effect of seed per treatment and seedling foliar application with polyamine compounds on the activity of antioxidant enzymes, routine and Seed yield was monitored under drought stress. This study was created out in 3 stages in agricultural faculty and natural resources at Shiraz university during the 2019-2020 arable years. The first experiment was for the effect of pretreatment of Buckwheat seed with polyamines on germination characteristics which was performed as a two-factor factorial in a randomized complete block design with four replications in vitro.

Experimental treatments included drought stress at seven levels (zero, -0.2, -0.4, -0.6, -0.8, -1 and -1.2 MPa) and seed pretreatment with melatonin (zero, 0.125, 0.250., 0.375 and 0.500 mmol) and spermidine (zero, 0.5, 1, 1.5 and 2 mmol). The second experiment (greenhouse) and the third (farm) were performed as three-factor and split-factorial factories in a randomized complete block design with three replications, respectively. In greenhouse conditions, drought stress at three levels of irrigation (irrigation at 10, 40, and 70 % field capacity depletion), and on-farm drought stress at three levels: full-field irrigation (no stress), 8-day irrigation once (mild stress) and irrigation Applied once every 16 days (severe stress).

In the first stage, the results of the laboratory section showed that different treatments of spermidine and melatonin in comparison with the control treatment had a significant effect on germination traits so that under drought stress concentrations of 1.5 mM spermidine and 0.375 ml Melatonin molar had the greatest effect on improving dilar germination, so they were selected as experimental treatments in greenhouses and farms. In greenhouse experiments, the three-way interactions of drought stress, seed pretreatment and foliar application of spermidine and melatonin on the activity of antioxidant enzymes and proline content were significant and the highest amount of catalase was 259.8 mg (mg protein). Per minute) and proline 5.12 (μg / ml) in combination of seed pretreatment with melatonin (0.375 mmol) and melatonin foliar application (0.375 mmol) under 70% discharge conditions Crop capacity was observed. In field conditions, the interaction of drought stress, seed pretreatment and foliar application of spermidine and melatonin had a significant effect on plant growth period and grain yield and the highest grain yield to seed pretreatment with melatonin with foliar application. With a concentration of 0.375 mmol and normal moisture conditions were allocated.

Seed pretreatment and seedling treating with melatonin in 0.375 mmol concentration, showed more effects in Buckwheat plant in both greenhouse and open field condition and the highest yield (538.2 kg/ha) seen in this concentration too.

Improving the efficiency of herbicides and reducing their consumption through the use of additives materials is one of the important strategies in sustainable weed management. Using reduced doses of herbicides with additives can reduce herbicide use, increase their effectiveness, and improve the health of food products. Therefore, this study investigated the effects of mixing herbicides with salicylic acid and cocowet adjuvant on corn yield, yield components, and weed control under Shahrood climate conditions.

  A factorial experiment was conducted as randomized complete block design with three replications at the research field of Shahrood University of Technology. Factors included weed control method at four levels: control (no treatment), weeding throughout the growing season, recommended herbicide dose (nicosulfuron 2 L.ha-1) and reduced herbicide dose (nicosulfuron 1 L.ha-1) as the first factor, foliar application of salicylic acid and non-application of salicylic acid as the second factor, and cocowet in two levels, 2 liters per hectare and non-application of cocowet as the third factor. Treatments were performed at the 6-leaf stage. At the end of the season, corn traits were sampled and measured. The investigated traits included the number of rows per ear, the number of grains per row, the weight of 100 grains, the harvest index, grain, and biological yield, density and dry weight of broad and narrow leaf weeds.MSTATC software was used to conduct an analysis of variance (ANOVA) on all collected data. Significant differences between means correspond to a probability level of 0.05 according to the LSD test.

The minimum grain number per row (20.2), biological yield (1.326 kg/ha), and grain yield (2,544 kg/ha) were observed when salicylic acid was not applied in weed-free conditions. The highest harvest index of 33.91 percent was obtained by applying cocowet under weeding conditions, while the lowest harvest index of 14.62% was observed in the control group (without cocowet consumption and no-weeding). Salicylic acid foliar spraying in conjunction with weeding, 1 liter of herbicide, and 2 liters of herbicide resulted in harvest index increases of 28.5, 67.9, and 83.2% in comparison to the absence of salicylic acid. In addition, the results demonstrated that foliar application of salicylic acid under weeding conditions increased the biological and grain yield of maize by 12.5% and 44%, respectively, compared to non-application. In this regard, researchers reported that the interaction effects of salicylic acid and herbicide could reduce weed dry weight and increase maize grain and biological yield. The effects of salicylic acid on physiological and biochemical processes, such as photosynthesis, ion uptake, membrane permeability, enzyme activities, flowering, heat production, and plant growth and development, are well documented. Similar reductions in population and dry weight of narrow-leaved weeds were observed when reduced herbicide doses were combined with cocowet, according to the findings of the present study. Low doses of herbicide combined with cocowet increased the yield of corn by 14 percent. In this regard, researchers reported that nicosulfuron applied with petroleum and vegetable oil adjuvants enhanced weed control.

Based on the findings of this study, the use of salicylic acid can increase corn's growth and competitiveness against weeds, while cocowet adjuvant has the potential to reduce herbicide use by increasing herbicides' use efficiency.

Drought stress is one of the most impactive factors of Severe modification in plant physiology, eventually leading to a reduction in crop productivity. Increasing growth, yield, crop quality, and reducing the side effects of drought stress are some of the important roles that potassium silicate plays in plants. In order to study the effects of late-season drought stress and foliar application of potassium silicate on yield and yield components of spring genotypes of canola, a factorial split-plot experiment was conducted in Karaj, Iran in a randomized complete block configuration with three replications for two years of cultivation (2016-2018). The irrigation was performed at two levels in this study, including routine irrigation (control) and interruption of irrigation from the pod formation stage. Potassium silicate foliar application at two levels comprised of 0 and 4 g liter-1 in factorial status in main plots and five Brassica napus L. genotypes including OG×AL, RGS×SLM, DALGAN, RGS003 and RGS×Okapi in subplots. The authors found that the interaction impact of irrigation, the application of potassium silicate foliar, the genotype of the number of pods per plant, the number of seeds per pod, the yield of seeds, the level of leaf proline, the glucosinolate and the temperature of the canopy were significant. It is proposed that OG×AL genotype be used in regular irrigation and application of potassium silicate and in late-season dry conditions and in the application potassium silicate of RGS×SLM and DALGAN genotypes.

In order to investigate the effect of ellagic acid on the growth of seedling and the qualities of soybean in accelerated aging conditions, a pilot was designed in 2019 in the research laboratory of the Shahrood University of Technology. The treatments included aging seed in two levels (unaged seeds and aged seeds) and priming at seven levels (control, distilled water, 25, 75, 50, 100, 125 mg/L with ellagic acid). A pilot study as a factorial experiment with a completely random-base design (CRD) in three replications was carried out under a germinator environment in accordance with standards. To prepare aged seeds in the laboratory, the seeds were incubated at 41°C and 95% relative humidity for 72 hours. Seed priming was soaking with ellagic acid for 6 hours in accordance with the principles of seed aeration. The aging reduced Vigor Index, Allometric Growth Ratio and Seed Reserves Use Rate. The increasing of the malondialdehyde had a negative effect on germination percentage through the influence of Vigor Index and α-amylase activity enzyme. The application of ellagic acid increased the germination percentage in unaged seeds and aged seeds through increasing the activity of α-amylase activity enzyme. The priming of seeds with ellagic acid reduced the malondialdehyde and electrical conductivity. Based on the results of research, the application of 50 mg/L of ellagic acid can be introduced as the best concentration of this material. It can also be suggested that the use of ellagic acid as a seed priming improves the effects of seed aging on soybeans.

Aging seed can be defined as loss of seed quality, viability and vigor. This process is irreversible over time and its intensity increases with increasing temperature and humidity. Aging seed is one of the major factors reducing quality and quantity in the agricultural sector, especially oilseeds. The use of antioxidants can reduce the damaging effects of aging. Ellagic acid is a natural plant antioxidant that can play a role in reducing the effects of stress on plants. This substance is a phenolic compound and among different antioxidants, due to its polyphenolic properties, it is one of the best scavengers for oxygen free radicals.

To investigate the effect of ellagic acid on improving the quality of plants obtained from normal and aged soybean seeds, an experiment was conducted in the research farm of Shahroud University of Technology during the two cropping years 2019 and 2020. In this study two sets of seeds including control seeds (un-aged) and aged seed were used and ellagic acid (50 mg. l-1) was applied for control, seed pretreatment, foliar spray and seed pretreatment+foliar spray. Farm research was conducted a factorial experiment based on a randomized complete block design (RCBD) in three replications. Soybean seeds var. DPX were collected from Mazandaran agricultural research center. The water content of seeds was 12%. The seeds were those that harvested in the same year and kept in a controlled storage room at the temperature between 14 to 17 °C and relative humidity of 30 to 40% at the Agricultural Research and Training Center and Natural Resources of Mazandaran Province. To prepare aged seeds in the laboratory, the seeds were incubated at 41°C and 95% relative humidity for 72 hours. Seed pretreatment with a concentration of 50 mg.L-1 ellagic acid was performed under ventilation condition for 6 hours. The seeds were then dried in the shade and used to continue testing and measuring traits compared to normal seeds. Foliar application was done early in the morning at the beginning of flowering (R1) and in favorable environmental conditions.

The results showed that aging reduced the mean daily seedling field emergence by 61.39% compared to normal seeds. The ratio of chlorophyll a to b, total chlorophyll, stomatal conductance and membrane stability index in the leaves of plants from aged seeds decreased by 9.9, 6.3, 7.0 and 28.9%, respectively, compared to the control. The amount of free amino acids and soluble sugars in the leaves of plants from aged seeds increased compared to normal seeds. Pretreatment of normal and aged seeds with ellagic acid increased the mean daily seedling field emergence by 23.1% and 19. 7%, respectively. The content of insoluble sugars were increased with application of both pretreatment and foliar spray of ellagic acid 32.0% respectively. The highest oil yield in both conditions was observed with application of both pretreatment and foliar spray of ellagic aicd. The yield seed increased with ellagic acid compared to the control 23.6%. Grain yield was higher than 23.2% in the plants that had received ellagic acid in a form foliar spray. In the end, the pretreatment+foliar spray of ellagic acid had the highest grain yield, which increased to control 55.5%.

However, in this study, the application of ellagic acid as a seed pretreatment and foliar spray had a positive effect under normal and aging conditions, but in the scope of the research, the combined application of ellagic acid as seed pretreatment and foliar spraying can be recommended to increase seed yield and seed oil yield in soybean. In general, ellagic acid can be introduced as a powerful antioxidant in aging conditions to reduce some of the destructive effects of the reactions involved in aging.

Seed aging is a phenomenon that causes a lot of economic losses every year and it is necessary to use new and efficient methods to deal with it. B vitamins have a defensive and antioxidant role and they are effective in growth and development, so it is possible that they can heal the effects of seed aging. For this purpose, an experiment was conducted at Shahrood University of Technology in March 2017 to investigate the effect of seed pretreatment with B group vitamins on the growth and yield of canola in seed deterioration conditions. The experiment was factorial based on randomized complete block design with 3 replications. Experimental treatments were 3 levels of seed deterioration (0, 50 and 100 hours) and 7 levels of seed pretreatment with B vitamins (No pretreatment, Distilled water, thiamine, Riboflavin, Niacin, Pantothenic acid and Pyridoxine) with a concentration of 100 mg/l. Seed deterioration was done at 40⁰C and seed pretreatment for 8 hours. The  results showed that all the measured traits were decrease affected by seed deterioration and only the amount of anthocyanins increased. In severe deterioration, seed pretreatment with distilled water and pyridoxine increased protein and oil yield respectively. Pantothenic acid pretreatment increased the amount of anthocyanins, total chlorophyll and grain yield at severe deterioration levels. This treatment increased grain yield by 143 percent compared with plants grown from seeds without pretreatment. In general, among the treatment investigated in this study, the pretreatment of seeds with pantothenic acid and thiamine improved and increased many traits such as seed yield, oil and protein content. The advantage of these treatments was quite obvious in normal seeds but in aged seeds there was no significant difference with distilled water. Therefore, the results showed that in aged seeds, a similar result can be achieved by using distilled water with less cost.

Germination is considered the first and most important stage of establishment and consequently, successful competition which is influenced by genetic and environmental factors. Among the environmental factors influencing the germination, temperature and light are the most important ones. Using different models, the germination response of seeds to temperature can be quantified; therefore, this study was performed to investigate the effect of temperature on germination and to quantify the germination response of Buckwheat seed (Fagopyrum esculentum Moenc) to temperature using nonlinear regression models and thermal-time model.

The seeds were germinated in 4 replications of 25 seeds under 8 constant temperature treatments (5, 10, 15, 20, 25, 30, 35 and 40 ° C). Using a three-parameter logistic model, Buckwheat seed germination was quantified at different temperature levels and the percentage and time to reach 50% germination were obtained. Four nonlinear regression models and a thermal-time model were used to quantify the response of Buckwheat seed germination rate to temperature. To compare the models and determine the most appropriate model, the root mean square error index (RMSE), coefficient of determination (R2), coefficient of variation (CV) and standard error (SE) were used for the observed germination rate versus the predicted germination rate.

The results indicated that temperature affected the seedling length, normal seedling percentage, seed vigor and the germination rate as well as germination percentage. Also, the results showed that germination characteristics increased with increasing temperature up to 20 and 25 °C. Comparison of the three models based on the root mean square error (RMSE) of germination time, the coefficient of determination (R2), CV and SE, the best model to determine the cardinal temperatures of Fagopyrum esculentum was the dent-like model. The results of thermal-time model showed that the base temperature of Fagopyrum esculentum seeds was 4.01 ° C and the thermal-time coefficient was 1242.6 h° C.

Utilization of non-linear regression models (segmented, dent-like and beta) and thermal-time model to quantify the germination response of Fagopyrum esculentum response to different temperatures led to acceptable results. Therefore, germination rate and percentage may be predicted using the outputs of these models at different temperatures.

Changes that occur during aging affect seed quality. Vigor is the first component of seed quality that decreases with aging seed, and followed by a decrease in germination capacity, seedling growth and establishment. The seeds of soybeans are classified in the orthodox seeds. These seeds contain high amount of lipid and protein. Seed viability can only be maintained until few months of storage under normal conditions. One of the important steps in soybean seed industry is maintaining seed quality during storage condition for the planting during next growth season or sales. Lack of a proper storage condition would affect the biochemical and physiological nature of soybean seeds and intensify their aging. Changes that occur during deterioration condition affect seed quality. Through the process of deterioration, seed vigor is the first traits of the seed quality that decreases, followed by a decrease in germination capacity, seedling growth and establishment. Wide range of deteriorative conditions (especially moisture content and temperature) may affect seed quality during storage which may lead to seed aging. Hence, to stimulate germination and increase the establishment of seedlings from ageing seeds, treatment can be done using different materials such as brown seaweed extract. To continue the experiment, normal seeds and aged seeds were sown in June 2018 and 2019 at a depth of 2 cm. Each plot consisted of 4 lines 6 m long with a distance of 50 cm between the lines and 10 cm width on the lines.

A factorial experiment was performed based on a randomized complete block design with three replications at the research field of Shahroud University of Technology. In this study two sets of seeds including control seeds (un-aged) and aged seed were used and brown seaweed A. nodosum (0.3%) was applied for control, seed pretreatment, foliar spray and seed pretreatment+foliar spray. The brown seaweed extract was "Acadian™ Seaweed Powder" (produced in Canada) containing brown seaweed extract (Ascophyllum nodosum), and all the reagent and chemicals for experiments were purchased from Merck (Germany). Soybean seed Var. DPX. was collected from the Mazandaran agricultural research center. The water content of seeds was 12%. The seeds were those that harvested in the same year and kept in a controlled storage room at the temperature between 14 to 17 °C and relative humidity of 30 to 40% at the Agricultural Research and Training Center and Natural Resources of Mazandaran Province. For surface sterilization, soybean seeds were disinfected with 1% sodium hypochlorite for 60 seconds and then washed with distilled water. To prepare aged seeds in the laboratory, the seeds were incubated at 41°C and 95% relative humidity for 72 hours according to the method described previously. For each treatment, 100 g of the soybean seeds were soaked in 20 ml seaweed extract (0.3%) under ventilation condition for 6 hours, following by drying the seeds in the shade.

In this study, the results showed that the seed aging reduced the mean daily seedling field emergence, content of soluble sugar, leaf area index, stomatal conductance, oil yield and seed yield and also, increased the electrical conductivity and free amino acids content in the field condition. Whereas, the seed pretreatment with the seaweed extract in normal and aging conditions increased mean daily seedling field emergence 15.31% and 55.03% respectively. The values of leaf area index, stomatal conductance, oil yield and seed yield were increased with application of both pretreatment and foliar spray of seaweed extract, 34.51%, 23.72%, 91.68% and 87.85% respectively. Seed pre-treatment and foliar spraying with Ascophyllum nodosum brown seaweed extract at a concentration of 0.3% improved the deteriorated effects and significantly increased seed yield.

This study concludes that the seaweed extract is effective to minimize negative effects of aging on seeds performance and has a great positive effect on the physiological and agronomic traits of soybean plant. Among the four methods used in this study, the seeds pretreatment+foliar spray was more effective.

An experiment was conducted in the research field of Shahroud University as a factorial based on completely randomized blocks in three replications to study the effects of marjoram extract on some qualitative characteristics and grain yield of soybean. The first factor was foliar application of extract in three levels (distilled water spraying, extract spraying of 40 and 60%) and the second factor was marjoram extract in five levels (no pretreatment, pretreatment with extract of 40 and 60% each for 6 and 9 hours). Foliar applications of 40% and 60% marjoram extract increased leaf anthocyanin by 11.2 and 6.5%, respectively, when compared to the control. The highest grain number per pod and grain yield were observed after a 6-hour pre-treatment with concentrations of 40 and 60% extract, followed by a foliar application of 40% extract. Pre-treatment with concentrations of 40% and 60% for 9 hours increased relative water content by 34% when compared to the control. Foliar application of 40 and 60% marjoram extract increased leaf flavonoid content by 1.56 and 1.71%, respectively, when compared to the control. According to the findings, a pre-treatment with a 40% concentration for 6 hours followed by a foliar application of a 40% extract is the best treatment combination for improving the quality characteristics and grain yield of soybean.

In order to study the effects of late-season drought stress and foliar application of potassium silicate on yield and yield components of spring genotypes of canola, a factorial split-plot experiment is conducted in Karaj, Iran in a randomized complete block configuration with three replications for two years of cultivation (2016-2018). The irrigation is performed at two levels in this study, including routine irrigation (control) and interruption of irrigation from the pod formation stage. Potassium silicate foliar application at two levels is comprised of 0 and 4 g liter-1 in factorial status in main plots and five Brassica napus L. genotypes including OG×AL, RGS×SLM, DALGAN, RGS003 and RGS×Okapi in subplots.  The results show that the measured properties are affected by the applied treatments. Full irrigation with foliar application in OG×AL genotype results in highest seed yield (5620 Kg/ha) and total chlorophyll content (1.71 mg/g.FW) increase stomatal resistance, leaf proline, leaf soluble and carbohydrates, decreasing total chlorophyll content and relative leaf water content. Under drought stress conditions, DALGAN and RGS× SLM genotypes have higher yield, which indicates its better performance under stress conditions. Finally, our research demonstrates Potassium Silicate's beneficial effects in improving the drought tolerance of canola plants, particularly at the end of the season. Our study will act as a foundation for any attempt in new approaches to mitigate drought damage, establishing a functional connection between the position of potassium silicate, physiological response, and drought stress tolerance in canola plants.

Increasing use of silver nanoparticles in agriculture and industry attracted more attention to the negative effects of their accumulation in environment. In this study, the effect of citric acid and hydrogen sulfide treatment on the morphological and physiological responses of green bean plants under silver nanoparticles stress was investigated. The results showed that nanosilver stress significantly reduced leaf area, plant height, leaf and pod dry weights and made a significant increase in total flavonoids and anthocyanins content and superoxide dismutase and glutathione-S transferase activities. Nanosilver stress increased malondialdehyde content and electrolyte leakage indicating a high oxidative and cell membrane damage, whereas these values ​​were lower in plants treated with citric acid and hydrogen sulfide. Furthermore, the highest growth indices were observed in control plants, plants treated with inducers and plants under stress, respectively, which indicates the effective role of inducers in stress relief. These results showed that citric acid and hydrogen sulfide mitigated the damage caused by nanosilver stress in green bean plants by reducing free oxygen species accumulation and preventing lipid peroxidation leading to increased growth rate in stressed plants. These findings can be used to reduce crop damages in regions contaminated with nanoparticles.

Drought is a restriction in crop production in arid and semiarid regions. It is forecast that climate change may cause droughts shortly. After oxygen, silicon (Si) is the second most common element in the soil. In reducing both biotic stress (e.g., plant diseases and pest damage) and abiotic stresses such as salinity, drought, aluminum toxicity, heavy metal toxicity, nutrient imbalance, lodging, radiation, high temperature, wounding, and freezing.

In order to study the effects of terminal drought stress and foliar application of potassium silicate on yield and canola spring genotypes components, a factorial split-plot test was conducted in Karaj, Iran in a full randomized block configuration with three replications for two years of cultivation (2016-2018). The irrigation was performed at two levels in this study, including routine irrigation (control) and interruption of irrigation from the pod formation stage. Potassium silicate foliar application at two levels comprised of 0 and 4 g liter-1 in factorial status in main plots and five Brassica napus L. genotypes including OG × AL, RGS × SLM, DALGAN, RGS003 and RGS × Okapi in subplots. SAS Ver 9.1 statistical analysis was used for variance analysis.

Combined variance analysis showed that the impact of the year on some characteristics seed number in silique, silique length and seed yield was significant. Also, the effect of irrigation was significant on seed yield. The effect of genotype on plant height was significant indicating that the genotypes had different reactions. The interaction effect of irrigation × genotype on Harvest index was significant. The interaction effect of Irrigation × Potassium Silicate × Genotype on branch number, silique number, silique length, seed number in silique, seed weight, biological yield, seed yield, oil content and oil yield was significant. The mean comparison of irrigation and Potassium silicate interaction demonstrated that the most grain yield was observed in normal irrigation and the least value related to cut off irrigation at pod formation stage. The results indicated that, irrigation, foliar application of Potassium silicate and their interaction had significant effect on growth and agronomic traits and increased them.

Finally, our study showed the beneficial effects of Potassium Silicate in improving the drought tolerance of canola plants, especially at the end of the season. This can provide a basis for attempting new strategies to reduce the damage from drought and create a functional link between the role of silicon, physiological response and tolerance to drought stress in canola plants. According to the results, in the case of application of Potassium Silicate and normal irrigation, the promising genotype of OG×AL, with the highest seed and oil yield, is recommended as standard. Also, in the case of application of Potassium Silicate and late-season drought stress (restricted irrigation from the pod formation stages), RGS × SLM and DALGAN with the highest seed yield, is recommended.

In order to investigate the role of foliar application of yeast extract on physiological and Biochemical properties of cowpea (Vigna sinensis L.) under drought stress conditions, a factorial experiment has been conducted as a randomized complete block design with three replications in Agriculture Campus of Shahrood University of Technology (located in Bastam) during 2017 under drought stress and foliar application of yeast extract. Drought stress involves two stages of 50 present flowering and 50 present pod formation with control treatment (without irrigation interruption). Foliar application of yeast extract (two, four, six g/L, and control) are repeated twice with a seven-day interval, with the first one being 30 days after planting. Results show that drought stress has decreased relative water content of leaves. In contrast, relative water content (5.82%), proline content (30.74%), leaf flavonoid (83%), nitrogen (3.82%), phosphorus (22.22%), and potassium (43%) are among the traits that have increased with the use of yeast extract, compared to the control. Six g / L of the yeast extract has increased grain yield (1.02 t ha-1), leaf anthocyanin (0.072 mg /g fresh weight), and proline (31.62 mg /g fresh weight). It can be said that a concentration of six g/L of yeast extract can be useful to reduce the severity of drought stress. The yeast extract can act as an ecological strategy to improve the defensive response against environmental stresses.

Sunflower (Helianthus annuus L.) is a major worldwide oilseed crop that develops slowly during the initial weeks after planting. Weed competition with sunflower during the first four weeks after crop emergence can reduce sunflower yield significantly. Promoting seed germination is the most direct way to improve sunflower growth and competition with weeds. Per-treatment of seed by cold plasma through accelerating seed germination can increase competitive ability of plant with weeds. Cold plasma treatment significantly increased wheat growth and yields. Thus, increasing plant growth can improve competitive ability of it with weeds. The aim of this study was to investigate the effect of cold plasma treatment on growth and yield of sunflower in competition with weeds.

This experiment was carried out as factorial based on randomized complete block design with three replications at Shahrood University of Technology (latitude of 36° 25 'N and longitude of 54° 57' E with an elevation of 1345 m) in 2016. Experimental factors were including cold plasma at six levels: control, hydro-priming of seeds for 10 hours, pretreatment of seeds with cold plasma radiation for 15 and 30 seconds, hydro-priming of seeds for 10 hours + cold plasma radiation for 15 and 30 seconds and weed control at three levels: control (no weeding), weeding all season and application of trifluralin (1200 g. a.i. ha-1). Dielectric barrier discharge plasma jet was operated in ambient air under sterile conditions in the laboratory of Faculty of Physics, Shahrood University of Technology. After seed priming in distilled water for 10 hours, sunflower seeds were taken in petri plates and treated with the plasma for determined times. Seeds were planted in the field immediately after cold plasma treatment. Seed number per head, 100 seeds weight, harvest index, biological, grain and oil yield of sunflower and weed dry weight were recorded. Statistical analyses of data were performed with statistical software MSTATC. Significant differences between means refer to the probability level of 0.05 by LSD test.

The results showed that seed number per head, biological and grain yield, harvest index, oil yield and weed dry weight significantly affected by interaction effects of treatments. Results showed that biological, oil and seed yield of sunflower decreased by 62.76, 56.11 and 55.86% in weed-infest than weed-free treatments respectively. Seed number per head and biological yield of sunflower significantly increased by using different pretreatments methods than control in the weed-infest conditions. Also, pretreatment of seeds with cold plasma for 30 seconds increased oil and seed yield of sunflower by 68.8 and 58.5 percent respectively in the weed infest treatment than control. The plasma treatment of soybean seeds up to 2 min showed positive effects on their germination rate and seedling growth. Cold plasma has essential roles in a broad spectrum of developmental and physiological processes in plants, including reducing the bacterial bearing rate of seeds, changing seed coat structures, increasing the permeability of seed coats, and stimulating seed germination and seedling growth. In addition, plasma treatment also could improve the physiological metabolism of the plant, such as de-hydrogenase activity, superoxide dismutase and peroxidase activities, photosynthetic pigments, photosynthetic efficiency and nitrate reductase activity. It seems that hydro-priming technique and cold plasma irradiation with improving seed germination and seedling early growth can led to more and faster germination and better competition of sunflower plants with weeds. 

Based on our results, pre-treatment of seeds by cold plasma and hydro-priming in addition to reducing weed biomass, could significantly improve the growth characteristics and yield of sunflower through increasing crop competitive ability with weeds.

Salinity is one of the environmental abiotic stresses and most important factors limiting the growth and production of plants around the world, which dramatically affect various aspects of plant growth and development through anatomical, morphological and physiological changes (Siringam et al., 2011). Saline environments decrease the growth and yield characteristics of plants and increase some physiological properties such as proline content and electrolyte leakage (Noreen et al, 2010). On the other hand, in the recent years, the role of symbiotic fungi and polyamines in plants tolerance to environmental stress such as saline conditions are pronounced. Morever, due to the importance of medicinal plants, many researches of plant sciences have focused on the various aspects of the application of these plants (Vafadar et al., 2018). Therefore, the present study was conducted to investigate the growth and physiological response of stevia (Stevia rebaudiana Bertoni) medicinal plant to inoculation with endophytic fungi and foliar application of spermidine polyamine under salt stress conditions.

This experiment was conducted at research greenhouse of Genetics and Agricultural Biotechnology Institute of Tabarestan (GABIT) at Sari Agricultural Sciences and Natural Resources University using factorial arrangement based completely randomized design with three replicates in spring and summer of 2016. The treatment consisted of salinity in three levels (0, 6 and 12 dS/m), fungal symbiosis treatments including four levels [non-inoculated (control), inoculation with Piriformospora indica (Pi), inoculated with Trichoderma virens (Trich) and co-inoculation of two fungi (Pi+Trich)] and foliar application of spermidine in three levels (0, 0.75 and 1.5 mM). Seedlings of stevia after inoculation with fungi transfered to adaptation chamber for 40 days and then moved to the greenhouse. Plants were irrigated with tap water until the end of vegetative stage and then irrigated with saline water treatments containing mixture of distilled and Caspian sea water. The Spermidine was foliar applied one week before salinity stress. Two weeks after salinity stress, leaf samples were prepared to measure leaf relative water content (RWC), electrolyte leakage (EL), proline content and soluble sugars. Finally, the plants were removed from the pots and the growth and yield traits were measured.

The result showed that in saline conditions, endophytic symbiosis, especially Pi+Trich, increased the stem dry weight (40-64%) and leaf dry weight (44-50%), relative water content (5-30%) and proline content (40-64%), and reduced EL (11-20%). Also spraying 0.75 mM spermidine signiticantly increased both leaf dry weight and plant height. Fungal symbiosis, especially Pi+Trich, and spermidine 0.75 mM resulted in an increase in the RWC. Also, spraying with polyamine spermidine at both concentrations of 0.75 and 1.5 mM increased soluble sugars and inoculated with endophytic fungi, particularly co-inoculation of two fungi, led to a reduction in the content of sugar (17%) in the stevia leaf. At the most levels of salinity and fungal treatments, spermidine, especially at the rate of 0.75 mM, led to increase in stem diameter (10-35%) and leaf area (35-46%).

In general, the results of the present study indicated a negative effect of salinity on the growth and physiological characteristics of the stevia plants. However, inoculation of endophytic fungi, particularly co-inoculation of Pi and Trich, improved the growth and physiological parameters and ameliorated adverse effects of salinity in stevia plants. Morever, the spermidine (especially 0.75 mM) induced salt stress tolerance in stevia plants and showed a synergetic effects with endophytic fungi in terms of the mentioned parameters.