فرید شکاری

As one of the most important cereals, bread wheat is an essential part of food security in the world, which supplies one-fifth of the total calories of the world population. Nowadays, the yield of wheat has been affected by climate change-driven drought as one of the most important abiotic stresses that has become an important threat to food security in the world. Root and stomatal traits are especially important in breeding plants to withstand drought stress. Stomata play a key role in controlling carbon dioxide uptake and water loss through transpiration. Therefore, stomatal characteristics are used as indicators of water status and plant growth, especially in drought stress conditions. Having a wide range of physiological and morphological characteristics, roots play an essential role in absorbing water and nutrients. They are also the first organ that sends signals to control the stomata in response to dryness. Therefore, the difference in the structure of the root system can cause the difference between the performance in different cultivars. This study was conducted to investigate stomatal characteristics and their relationship with the root system and plant performance in 24 bread wheat lines and cultivars.

To investigate the relationship between stomatal dimensions and density with the root system, an experiment was conducted on 24 bread wheat genotypes in the form of a randomized complete block design with three replications in the rainfed conditions of the research farm at Zanjan University Faculty of Agriculture in the crop year 2018-2019. In this experiment, PVC pipes were used to study the root system. Twelve seeds were planted in each tube, which were thinned to seven after germination. In each experimental unit, there were two tubes for each genotype, one of which was used to evaluate traits and final yield, and the second tube was used for root studies. Stomatal traits, including the length and width of stomata and number of stomata per unit area, root traits including root length, root diameter, root volume, root surface, and root biomass, and seed yield were measured in the end. The resulting data from the measured traits were analyzed in the form of a randomized complete block design, and the averages were compared using the LSD method. The data were analyzed using multivariate statistical analyses, including regression analysis, path analysis, and factor analysis, and cluster analysis was used to group genotypes. Statistical calculations were done using SAS 9.0 and SPSS 21 software.

The results of analysis of variance and mean comparison showed high variability among genotypes for all measured traits. The results of the mean comparison of genotypes showed that genotypes 2, 5, 8, and 16 had the highest yield, and genotype 23 had the lowest yield among the examined genotypes. The highest number of stomata on the upper and lower leaf surfaces belonged to genotypes 5 and 2. In terms of root traits, the highest diameter, volume, length, root surface, and root dry weight at a depth of 0-25 cm were recorded for genotypes 2, 3, 18, and 5, respectively. There was a high and significant correlation between the yield and the number of stomata on the upper and lower leaf surfaces, the length and width of  the stomata on the upper leaf surface, diameter, volume, dry weight, and root surface at a depth of 0-25 cm in the soil. Based on the results of stepwise regression analysis, two variables, the number of stomata on the lower leaf surface and root dry weight at a depth of more than 25 cm explained 91.4% of the changes in grain yield. According to the results of the causality analysis of the number of stomata on the lower leaf surface, the most direct effect had a positive effect on seed yield. The results of factor analysis grouped the studied traits into three factors with 82.48% variability justification. The shares of the first, second, and third factors to explaining data changes were 48.86%, 24.62%, and 8.99%, respectively. Based on the plot obtained from factor analysis, genotypes 2, 5, 8, and 16 had high values for the first and second factors. According to the coefficients of the factors, it can be claimed that the genotypes located in this area have high performance, a high number of stomata, and strong root traits, which were found at the soil depth of 0-25 cm. For this reason, these are the genotypes that could produce high yields by absorbing water from the surface layers of the soil by having a large number of stomata and carrying out more photosynthesis. Moreover, the investigated genotypes were divided into three groups from cluster analysis by the ward method and Euclidean distance. Genotypes 2, 5, 8, and 16 were placed in the first group and had the highest mean values for grain yield traits, number and width of stomata on the upper and lower leaf surfaces, and root traits including diameter, volume, and dry weight at a soil depth of 0-25 cm, and root diameter at a depth greater than 25 cm. The lowest values for stomatal length were observed in both leaf surfaces. These were the best genotypes for cultivation in dry conditions.

A strong superficial root system can provide the plant with water from scattered rains that occur with low frequency at the end of the growth period. On the other hand, the increase in the number of stomata along with their smaller size reduces leaf pores and enables a faster response of the stomata, and the rapid response of the stomata maximizes water use efficiency. Therefore, having a strong superficial root system along with high stomatal density can increase seed yield in dry conditions.

Oilseed rape is one of the most important sources of vegetable oil in the world, and its seed contains more than 40% of oil, and the meal obtained from oil extraction has more than 35% of protein, and currently it ranks third among oil plants after soybean and oil palm. in the world. The existance of environmental stresses, such as drought stress, causes a significant decrease in oilseed rape yields. Therefore, breeding for drought tolerance is very important, and creating high yielding and early maturing or drought tolerant cultivars is one of the important goals of breeders. The purpose of this study was to determine the best general and specific combiners and the amount of heterosis compared to the superior parent in spring rapeseed using line×tester analysis in two conditions of normal irrigation and drought stress.

Seven high-yielding rapeseed lines were crossed with five testers with a range of early maturity in the 2018-2019. The first generation hybrids along with 12 parents (47 genotypes in total) were evaluated in the randomized complete block design with three replications in two conditions of normal irrigation and terminal drought stress (irrigation cut off at the beginning of podding stage) in the 2019-2020. The studied traits included physiological maturity date, plant height, number of pods per plant, pod length, number of grains per pod, height of the first pod from the ground, 1000-grain weight, seed yield, oil percentage and oil yield.

The results of analysis of variance in both normal irrigation and drought stress conditions showed a significant difference between hybrids for all investigated traits, which indicated a significant diversity between genotypes. In analyzing the effect of hybrids into the relevant components, the interaction effect of line × tester was significant for all the traits under normal irrigation conditions and also under drought stress conditions except for the height of the first pod from the ground, and oil yield. The effect of parents versus hybrids was significant in normal for all traits except the number of seeds per pod under normal irrigation conditions and except for plant height, pod length and number of seeds per pod in drought stress conditions, which indicates the existence of heterosis for these traits. For the trait of physiological maturing, among the lines, line 6 showed the highest negative general combining ability under normal irrigation and drought stress conditions, and tester 5 showed the highest negative general combining ability among the testers under normal irrigation and drought stress conditions. Tester 5 was contributed in early maturing T5×L3 hybrid under drought stress conditions. L1 and L5 in both conditions and T2, and L3 and L4 in normal irrigation conditions and T1 in drought stress conditions were identified as the best general positive and significant combiner for the number of pods per plant, and hybrids T5×L1, T1× L5, T2×L4, T4×L4, T1×L7, T1×L6, T2×L7, T3×L2, T5×L7, and T4×L3 were the best specific combiner to increase the number of pods per plant in both experiment conditions. T4 was the most significant positive general combiner under normal irrigation conditions and drought stress for the 1000-grain trait. Also, regarding the positive significant specific combining ability for this trait hybrids T2×L7, T3×L7 in both conditions, and in addition hybrids T1×L7 and T5×L4 under normal irrigation conditions and hybrids T1×L6 and T3×L5 under drought stress conditions showed the highest amount. The most significant positive general combining ability in grain yield was determined to T5 and L1 and L6 in both conditions. The best significant positive specific combining ability were T2×L7 and T3×L7 in both conditions. The highest positive and significant amount of general combining ability of the amount of oil, was given to T3 and T5 and L6 in both experimet conditions, and T4 and L7 in normal irrigation conditions and L5 in drought stress conditions. T1×L6, T5×L1, T2×L5, T3×L1, T5×L3 and T4×L4 were among the best hybrids in both conditions. In normal irrigation conditions, T2×L3, T4×L3, T5×L1, T4×L6, and T5×L3 and in drought stress, T5×L1, T2×L3, T2×L4, T4×L4, T4×L3, T4×L5 and T2×L7 had the highest amount of heterosis in the positive direction for the number of pods per plant. The trait of the number of grain per pods, T2×L3, T4×L3, T5×L1, and T2×L5 under normal irrigation conditions and T5×L6, T3×L6, and T5×L3 under drought stress condition had the highest amount of heterosis.

The estimation of traits' combining ability showed that T5 and L1 and L6 were the best general combiners to increase grain yield. T3×L7 and T2×L7 hybrids were the best specific combiner for increasing grain yield under normal irrigation and drought stress conditions. Also for the 1000-seed trait, T3×L6, T4×L1, T5×L4 and T1×L1 hybrids under normal irrigation conditions and T3×L7, T1×L6, T2×L6 and T3×L3 hybrids under drought stress conditions have the highest amount of heterosis. The number of pods per plant and the number of grain per pods under normal irrigation conditions, T2×L3, T4×L3 and T5×L1 had significant positive heterosisTherefore, their parents can be suggested for hybrid varieties production programs.

The production of oilseeds, edible leaves, and secondary metabolites of dragon's head makes it an important food, forage, and medicinal plant. Choosing a proper planting date and plant nutrition can make a significant effecton crop plantsgrowth, quality and yield.The effects of planting date (16 March, 14 April, and 13 May 2019) and foliar application of zinc sulfate (zero as control, 2 and 4 g.L-1) on growth indices and seed yield of dragon's head was evaluated under a field experiment.Delayed planting date reduced the days to flowering, days to seed ripening, plant height, leaf area index (LAI), crop growth rate (CGR), relative growth rate (RGR) and grain yield, and yield components.In contrast, the use of zinc sulfate increased plant height, LAI, CGR and RGR. There was a correlation between plant height and number of branches and consequently there were more capsules per plant.The highest effect of zinc sulfate application on seed yield and yield components was observed in the first planting date and with delay in planting, the efficiency of zinc sulfate fertilizer application decreased. On the third planting date, zinc sulfate application had no significant effect on grain yield. As a result of late planting, fewer branches, fewer capsules per plant, and smaller seeds contributed to the yield reduction.It was found that early cultivation and application of zinc sulfate increased plant height, number of branches, number of capsules per plant, 1000-seed weight, and thus seed yield, by increasing the days to flowering, days to ripening, LAI, CGR, and RGR.

Investigating the effect of various sources of sulfurous compounds along with the inoculation of Thiobacillus bacteria on corn plants under stress conditions of lead and zinc metals, Factorial experiment of randomized complete blocks design was carried out in the Agricultural Research Greenhouse of Zanjan University in 2021. The treatments include elemental sulfur (0.75, 1.25 and 2 g/kg soil), sulfur with thiobacillus bacteria(biosulfur) (1, 2 and 3 g/kg soil) and potassium sulfate (0.5, 1 and 1.5 g/kg soil). The results showed traits were significant in the vegetative growth stage in all applied treatments. The treatments increased the amount of chlorophyll, enzymes compared to the control. Then decreased the leaf temperature, Increasing the length of leaf cells. also, it increases the leaf area and leaf production rate in plants. This increase was higher in sulfur treatment with bacteria. But the treatments of 2 grams of elemental sulfur and 1.5 grams of potassium sulfate caused stress in the plant and reduced the amount of traits compared to the control. Also, the plants in contaminated soil were stressed and the amount of the mentioned traits also decreased. However, with the application of treatments, the amount of carotenoid, total protein and peroxidase traits increased, which reduced the stress in plants and increased the amount of traits and growth indicators compared to control in contaminated soil. Sulfur treatment with bacteria, compared to other applied treatments, by activating the enzymatic and non-enzymatic defense system of the plant, causes the plant to tolerate stress and improve plant growth.

Investigations showed that the pollution of heavy metals, especially lead, in fields has caused tension and decreased yield. This issue has caused concern about the risk of consuming contaminated food for human health. The role of plant regulators in heavy metal stress conditions has been of interest in recent years. Lead and zinc (in high concentration) are toxic metals for plants, which are easily absorbed by the plant's root system. As a result, they cause damage to plant growth and development and prevent enzyme activity. Maize is economically important for harvesting seeds and fodder. However, in areas contaminated with metal stress, due to the absorption of metals by the plant, the yield of the cultivated plant in these areas decreases, for this purpose, an experiment aimed at the effect of concentration and different methods of salicylic acid hormone on growth, photosynthesis and anatomical characteristics. and physiological in corn under the stress of zinc and lead metals and also the possibility of reducing the risk of toxicity of these elements is investigated.

In order to investigate the mitigating effects of two methods of applying salicylic acid hormone on corn plants under heavy metal stress, the experiment was carried out as follows. The concentration of metals included: different concentrations of lead (0 and 250 mM) and zinc (0 and 2500 mM) and the treatments were with two methods of foliar spraying and priming in zero concentrations (distilled water), 750 and 1500 μmol salicylic acid and a group of seeds without stress and no treatment were considered as controls. By implementing a factorial design on morphological traits (height, plant temperature, temperature difference between the environment and leaves, and leafing ratio) and physiological traits (membrane stability index, chlorophyll fluorescence, proline, soluble sugars, carotenoid, protein and some enzymes) as well as the absorption of lead and zinc metals in the root tissue and the aerial part of the plant under hydroponic cultivation conditions. The obtained results were subjected to statistical analysis using SPSS statistical software. The mean comparison of experimental data was also done with Duncan's test. Excel 2003 software was used to draw the figures.

Morphological traits such as: plant temperature, difference between Environment and leaf temperature and physiological traits such as: proline, soluble sugars, carotenoid, protein and some enzymes increased and some other traits such as: height, and leafing ratio, index Membrane stability, chlorophyll fluorescence decreased compared to the control. These traits showed better results in seed priming treatment without stress. However, the use of foliar spray under lead-zinc and lead stress improved the stress effects by reducing the absorption of heavy elements by the root system.

SA activates the defense system of plants by synthesizing a number of proteins and increasing proline osmolytes and soluble sugars and enzymatic and non-enzymatic antioxidants such as carotenoids. As a result of reducing the oxidative stress and protecting the chloroplast membrane and the photosynthetic apparatus, the photosynthetic production is improved, resultly, the height and the proportion of the leaves increased. SA also prevents the absorption of heavy metals by the root system of the plant and its transfer to the aerial part of the plant, which reduces the signs of stress in the aerial part of the plant. By applying salicylic acid, some properties were improved by reducing the effects of stress. The use of foliar spraying improved the physiological and morphological traits during plant growth and worked better than the seed priming method. resultly, in farms with two metals lead and zinc, it is possible to tolerate the stress of these two metals by foliar spraying treatment.

In the last two decades, soil contamination with heavy metals has increased in many agricultural areas. Therefore, in order to investigate the interaction of mycorrhiza and putrescine on physiological characteristics, lead content, and yield of Lallemantia iberica under lead (Pb) stress, a factorial experiment was conducted in a randomized complete block design in the Research Greenhouse of the Faculty of Agriculture, University of Zanjan in 2018. Experiment consisted of Pb in four levels (0, 300, 600, and 900 mg Pb/kg soil) from the source of Pb(NO3)2, mycorrhiza at three levels (no inoculation, Funneliformis mosseae, and Rhizophagus intraradices), and putrescine in three levels (0, 0.5, and 1 mM). The results showed that among the Pb levels, 900 mg/kg caused the greatest decrease in the greenness index, relative water content, height, plant dry weight, root length, and grain yield, and increased electrolyte leakage, plant Pb concentration, colonization, and proline content. At all Pb levels, both fungi, especially F. mosseae, increased greenness index, relative water content, height, plant dry weight, root length, and yield, and decreased plant Pb concentration. At all Pb levels, the concentration of 0.5 mM putrescine decreased electrolyte leakage and plant Pb concentration, and increased proline content, plant dry weight, yield, and colonization. In all traits, putrescine had a synergistic effect with F. mosseae, but only 0.5 mM putrescine had a synergistic effect with R. intraradices. In general, the interaction of 0.5 mM putrescine with F. mosseae had an additive effect on plant growth, especially under Pb stress conditions.

In order to investigate the effect of salicylic acid application on reducing the effects of cold stress due to delayed planting in rapeseed genotypes, this experiment was conducted as a factorial-split plot during the 2014 and 2015 growing seasons in the Faculty of Agriculture, University of Zanjan, Iran. Interaction of the sowing date (11th September and 7th October) and salicylic acid (control (spray with distilled water), 250 µM and 500 µM) were as the main-plot and rapeseed genotypes (Karaj-3, L14, Okapi, Zarfam) were assigned to subplots. The effect of planting date* salicylic acid* genotype on winter survival percentage, grain yield and its components, harvest index, and biomass was significant. Delayed planting reduced survival percentage of all rapeseed genotypes; but the severity of reduction varied depending on the genotype. It was also found that the decrease in survival percentage due to delay in planting can be partially compensated for by the use of salicylic acid, which varied depending on the salicylic acid concentration and genotype. Delayed planting date reduced grain yield in all genotypes and salicylic acid application had the opposite effect and increased grain yield. Karaj-3 had the highest grain yield on 7th October planting date and 500 µM salicylic acid, while Zarfam had the lowest grain yield on 11 September and 0 µM salicylic acid. Application of salicylic acid compensated for part of the reduction in yield due to delay in planting, so that the lack of application of salicylic acid and the use of 250 and 500 μM salicylic acid in planting on 7 October caused grain yield reduction in Karaj-3 genotype by 36, 31 and 18% respectively, compared to 11 September, while grain yield in L14 genotype showed 26, 21 and 8% reduction respectively, compared to 11 September planting date. The grain yield of Zarfam genotype at delayed planting date decreased by 9% and 5% and increased by 13%, respectively, in conditions of non-application and application of 250 and 500 μM salicylic acid compared to the 11 September planting date. There was a positive significant correlation between grain yield components and winter survival percentage. Although delayed planting reduced grain yield, yeld components, harvest index, and biomass in all genotypes, the severity of the decrease varied among the genotypes. Consumption of salicylic acid moderated the effect of delay in planting and this modulatory effect was higher in the application of salicylic acid with a concentration of 500 μM than 250 μM. In general, the results showed that in both planting dates, the Karaj-3 genotype had the highest grain yield in all salicylic acid levels, so it is recommended for planting in areas with similar conditions.

In the last two decades, soil contamination with heavy metals, including lead (Pb), has been increasing. Pb is the most important heavy metal that has polluted the environment and caused symptoms of plant toxicity such as limiting root and shoot growth, blackening of the root system and decreasing photosynthesis and the quantity and quality of yield. In many agricultural areas of Iran, including Zanjan, the presence of heavy metals, especially Pb, is always associated with the growth stages of plants, including medicinal plants. Native medicinal plants of Iran, including Lallemantia iberica have an important role in the treatment and prevention of diseases. The seeds of this plant are reconstituent, stimulant, diuretic, and expectorant and have a high content of oil and omega-3 fatty acid alpha linolenic acid. The use of polyamines such as putrescine (Put) is one of the new strategies to reduce the harmful effects of environmental stresses such as heavy metals. Polyamines, as plant growth regulators, have a protective role against membrane damage and lipid peroxidation and are involved in regulating processes such as cell division, enzyme activity, vascular differentiation, flowering, fruit ripening, and root growth. Due to the contamination of agricultural soils near the industrial areas with heavy metals and the need for medicinal plants in the country, this study was conducted to investigate the effect of Put spraying on the growth and tolerance of L. iberica to Pb stress.

The experiment was conducted as a factorial based on a randomized complete block design with six replications (three replications for grain yield and three replications for other traits) at the research greenhouse of the Faculty of Agriculture, the University of Zanjan in February 2018. The experimental factors were Pb stress in four levels (control, 300, 600 and 900 mg Pb/kg soil) from the source of Pb(NO3)2 and Put in two levels (0, and 0.5 mM). The Pb amount in the test soil was measured at the beginning of the experiment and considered as control. The Put spraying was performed before flowering begins (with the observation of the first flower bud) during 2 steps (half concentration at the 10-leaf stage and the other half 7 days later to prevent Put accumulation). Greenness index, proline content, leaf area, leaf, stem, and capsule dry weight, total shoot dry weight, root length and dry weight, and tolerance index at the flowering stage and grain yield at the harvest stage were measured. Analysis of variance was done by using SAS (9.1) software. Mean comparison was performed by Duncan multiple range test at 5% probability level.

The main effects of Pb stress and Put spraying on all the traits were significant. The interaction effect between them on greenness index, proline content, leaf, stem, and capsule dry weight, total shoot dry weight, root length, tolerance index, and grain yield was significant while its effect on leaf area and root dry weight was not. Pb stress, especially at 900 mg concentrations, decreased leaf area, greenness index, leaf, stem, and capsule dry weight, total shoot dry weight, root length and dry weight, tolerance index, and grain yield and increased proline content. The highest grain yield and tolerance index was obtained in the non-added Pb. Within each four Pb levels, Put spraying had the maximum amount of measured traits than the non-Put. Growth restriction and improper development of the root system under Pb stress reduced water and nutrient uptake and subsequently affected chlorophyll and photosynthesis, thereby reducing leaf area, shoot growth and plant yield, which the positive and significant correlation of root length with total shoot dry weight, leaf area, and greenness index (r=0.87***, r=0.61**, and r=0.9***, respectively) confirms the above content. The positive role of the Put can be due to its effect on increasing cell division, which ultimately improves plant growth. Positive and high correlations of leaf area with grain yield (r=0.69***) and greenness index with grain yield (r=0.87***) confirm that any factor which increases leaf area enhances producing and storing assimilate in the plant, leading to increased grain yield.

Overall, measured traits affected by increasing Pb concentration in the soil, however, Put spraying had improvement effects on these traits and with an increasing root length, greenness index and leaf dry weight led to an increase in the tolerance index of L. iberica under Pb stress. Also, the highest grain yield was found in Put spraying under control. Therefore, given the crisis of the increasing concentration of heavy metals, especially Pb in the agricultural soils, Put application can be suggested to increase Pb tolerance in L. iberica and to use this plant in Pb-contaminated areas to restore lost vegetation.

This study was conducted to investigate the effects of salicylic acid (SA) and nanosilicon (n-Si) on some morphophysiological characteristics and essential oil of Lallemantia iberica under salinity stress and uncontrolled greenhouse conditions as a factorial experiment based on the randomized complete block design in 2018. The experimental factors included sodium chloride (0, 50, and 100 mM), SA (0, 1, and 2 mM), and n-Si (0, 0.5, and 5 mM). The SA and n-Si treatments were applied at the four-leaf stage (once every seven days) and the salinity treatment was applied at the six-leaf stage of the plant (once every four days) until fully ripening seeds of the plant (yellowing 90% of the leaves and capsules). The results showed that under salinity stress, the plant traits including height, aerial parts dry weight, chlorophyll content, and seed yield decreased and proline and essential oil increased. The application of SA and n-Si improved these traits under salinity stress. The main constituents of L. iberica essential oil included linalool (25%), geraniol (16%), β-cubebene (10.6%), menthyl acetate (9.8%), valencene (3.5%), germacrene-D (2.4%), β-caryophyllene (2.3%), and limonene (1.3%), all of which increased in the salinity treatments compared to the control. The application of SA and n-Si under salinity stress conditions increased limonene, linalool, geraniol, β-cubebene, β-caryophyllene, and valencene and decreased menthyl acetate and germacrene D. In general, the results of this study showed that the application of SA and n-Si could increase the tolerance of L. iberica to salinity stress by creating the osmotic regulation, protecting the content of photosynthetic pigments, and reducing oxidant damage.

Irrigation management and use of partial root irrigation under saline conditions is one of the sustainable production strategies in agriculture. The production of reactive oxygen species and the cytoplasmic accumulation of smolites is one of the most common plant reactions to salinity stress and dehydration under these conditions. However, few studies have been performed on the variation of enzymes and cellular osmotic regulators in similar salinity and water stresses under the same osmotic and matric potential levels on the two sides of the root and its differences with separate stress conditions. The aim of this study was investigated the effect of partial irrigation management on activity of peroxidase and catalase enzymes, proline content variation under different levels of similar osmotic and matric potentials, in leaves and roots of maize in Fajr cultivar (KSC 260), in greenhouse conditions.

A factorial experiment with two factors; stress type (salinity, drought and mix stress) and potential levels in three values (-112, -191, and -363 KPa) was performed on the basis of completely randomized design with 3 replications. The culture media was subdivided into two equal sections by nylon for uniform and same distribution of the root in the mixed treatments. At mixed stress, half of the roots were subjected to salinity stress and the other half to drought stress (at corresponding levels equal to the osmotic and matrix potentials). Handmade tensiometers were used for drainage in salinity treatments. Catalase, peroxidase, total protein and proline were measured in both shoots and roots. Also, total dry weight and root of corn plant were calculated. The results showed that with decreasing the potential level, the activity of root peroxidase and catalase had a similar trend (increase) only in individual drought treatments and the drought part of the mixed treatment. In the drought part of the mixed treatment compared to the individual drought treatment, with decreasing the potential level, the activity of root peroxidase increased by 18.5% and the activity of root catalase decreased by 6.28%. At the potential level of -363 bar, the dry weight of roots in drought treatment, compared to salinity and mixed treatment increased by 48.3% and 31%, respectively. Despite different changes in the amount of traits measured in salinity, drought and mixed stresses, at the same potential, no significant difference in total dry weight was observed.

Maize plant under the same osmotic and matric potential levels exhibits different physiological and morphological behaviors. The use of partial root irrigation system with saline water in mix treatment will cause less stress than salinity treatment at low levels of osmotic potential to the plant. It seems, modification of plant biochemical reactions is one of the successes of root irrigation method with saline water. Therefore, due to the scarcity of freshwater resources, partial root irrigation with saline water is recommended as a nearly desirable system compared to other full root irrigation systems.

Breeding new crop cultivars with efficient root systems carries great potential to enhance resource use efficiency, plant adaptation to unstable climates and improve yields. Current study was conducted to investigate the relationship between root characteristics with yield and yield components in 24 lines and cultivar of bread wheat using complete randomized block design with three replications in rainfed conditions of research farm of the University of Zanjan in 2017-18 and 2018-19 growing seasons. The results of combined analysis of variance showed the difference between year and high diversity between genotypes measured for most traits. According to the results of the study of genetic parameters, the highest heritability was related to the number of grains per spike (70.328%) and the heritability of the most root traits was low. There was a negative correlation between yields with the most root traits but root diameter. The results of sequential path analysis showed that in the first stage of chain 1000-grain weight, number of spikes per square meter and number of seeds per spike affected grain yield, and in the second stage, root dry weight and diameter greater than 25cm deep and root volume to a depth of 25cm with effects on 1000-grain weight, root volume greater than 25cm deep and root dry weight to a depth of 25cm with effects on spike number per square meter and root volume to a depth of 25cm with effects on seed number per spike, they Indirectly affected grain yield. The results of factor analysis led to the identification of four factors that explained 82.45% of the differences between the data. Based on the results of cluster analysis, the studied genotypes were divided into three groups. The cultivars and lines in the second group had the highest yield with the highest root volume, diameter, dry weight, surface and length to a depth of 25cm.

A greenhouse study was conducted to evaluate of salicylic acid foliar effect on morphological and biochemical characters of Stevia (Stevia rebaudiana) based on a Completely Randomized Design (CRD) experiment with three replications in Qazvin, Iran in 2016.  The treatments of this research were defined as salicylic acid foliar levels as 0 (control), 100, 300 and 600 µM which were applied three months after transplanting. Evaluated characters were as plant height, branch number, plant dry weight, leaves dry weight, branches dry weight, the ratio of leaf to total dry weight, the percentage and yield of stevioside, rebaudioside-A, rebaudioside-B and rebaudioside-c. The results of this study revealed that foliar levels of salicylic acid had a significant effect on all of the evaluated characters except for SPAD index. The treatment of foliar 100 µM salicylic acid led to a significant increase in plant height, stevioside percentage, rebaudioside C yield and its percentage compared with control treatment (18.2%, 91.7%, 160% and 186%, respectively). By increasing the concentration of salicylic acid foliar level to 300 µM, the branches dry weight, leaves dry weight, plant dry weight, stevioside yield, rebaudioside. A percentage and its yield were increased in comparison to control treatment (3.9%, 10.3%, 7.0%, 84.6, 78.3 and 100%, respectively). Finally the treatment of 600 µM salicylic acid foliar level was significantly led to an increase in lateral branches number, the ratio of leaves dry weight to branches dry weight, rebaudioside-B percentage and its yield compared to control treatment (365.8%, 43.0%, 383.3and 344.4%, respectively). Therefore, a concentration of 300 μM foliar application of salicylic acid can be effective for increasing the quantitative and qualitative performance of Stevia.

Oilseeds are an important part of agricultural products which are important for nutrition, in addition to industrial applications. Plant oils are used to cooking, manufacture of cosmetics, plastics, lubricants, and insulators for the electricity and as biofuels (to reduce greenhouse effect). Rapeseed is one of the most important oilseeds that ranks third after soybeans and oil palms. Rapeseed oil contains less than 2% erosic acid and low saturated fatty acid levels, which help to reduce blood cholesterol levels. This research was carried out to investigate the effect of priming of rapeseed with salicylic acid on yield and yield components the research farm at the University of Zanjan.

This research was carried out as a randomized complete block design with four treatments during growing seasons 2014-2015. Treatments in the research included a control (just distilled water), 50, 75 and 100 μM salicylic acid concentrations. The seeds were soaked for 12 hours in salicylic acid solution, then, seeds exposed to airflow and air-dried to return original state before treatment with salicylic acid. After seed treatment with salicylic acid at the pre-mentioned concentrations, the seeds were then sown in four plots in five replications. To remove the marginal effect and evaluate the factors, the 7 plants in the middle row of each plot were randomly marked. The relevant traits measured 15 days after the physiological maturity of rapeseed.

The results indicated that seed priming with salicylic acid caused a significant difference in yield, yield components and dependent traits. Salicylic acid treatments significantly increased the number of stems, pods, length and dry weight the plant, length of the pods and number of seeds in each pod, the seeds weight in main and secondary stems, total weight of seeds and dry weight of roots compared to control. In contrast, no significant effect was observed on the empty pods and 1000- seeds weight.

The results of this research showed that seed priming with salicylic acid can increase yield and yield components of rapeseed plants. This is due to the effect of salicylic acid on the number of pods in plants and the number of seeds in pods. Also, plant height and the secondary stems in plants increased with salicylic acid application. In addition, height increase, resulted in more development of reproductive organs, also allowed for an increase of leaf area index and greater carbon absorption potential in plants.

Pumpkin is one of the valuable medicinal plants which have high oil content in its seeds. The response of pumpkin was examined against controlled water deficiency with spraying salicylic acid under field conditions in 2015 and 2016 in split plot experiment based on complete randomized block design. The plants sprayed with 0, 0.5, 1 and 1.5 mM concentrations of salicylic acid at 5-6 leaf stages. After 15 days plants exposed to -0.3, -1.2 and -1.8 MPa water deficiency. Increasing water deficiency reduced RWC, chlorophyll and carotenoids content, plant height, number of nodes and branches per plant, fruit yield, fruit diameter, seed yield, number of seed per fruit and weight of 1000 seeds while it and also increased the diameter of mesocarp especially in -1.8 MPa treated plants. On the contrary, spraying with salicylic acid resulted in significant increase in RWC, chlorophyll and carotenoids contents, plant height, number of nodes and branches per plant, fruit yield, diameter of fruit, seed yield, number of seed per fruit and weight of 1000 seeds. Haghest salicylic acid effect observed at 1.5 mM concentration. Most of traits under study depicated their significant reduction at -1.8 MPa water deficiency, while other traits like leaf water content, plant height, chlorophyll a, b and total chlorophyll content, nodes per plant, number of branches and mesocarp diameter were reduced at -1.2 MPa. On the other hand, seed per fruit was increased significantly at -1.2 MPa as compared to -0.3 MPa water deficiency. The main reason for increment of seed number per fruit was due to reduction in mesocarp diameter and its weight. It seems that water deficiency changed the partitioning pattern of assimilates from fruit and shifted them to seeds against mesocarp or other parts of fruit. Among the yield components, seed number per fruit and number of fruit per land area had the most effect on yield formation. The variation in seed weight was not significant. According to results, pumpkin may considered as a tolerant plant to soil suction till -1.2 MPa, without a significant reduction in seed yield.

Each year a large amount of saffron petals which make up a significant proportion of saffron flowers are discarded as waste while this part of the flower also contains compounds such as phenol, anthocyanin, flavonoid and antioxidant properties. Two separate experiments were conducted using randomized complete block design with three replications in order to evaluate secondary metabolites, total phenol content and antioxidant capacity of petals in eight saffron populations under normal and once irrigation conditions  at the research farm of university of Zanjan on three year old saffron plants. In order to measure and determine secondary metabolites, total phenol content and antioxidant properties of saffron petal extract, UV-Visible  Metering Spectra, folin-Ciocalteu and DPPH were used, respectively. Combined analysis of variance under normal and once irrigation conditions showed that the difference between secondary metabolites and antioxidant properties was not significant in the two irrigation conditions. While, total phenol content was significantly higher under the once irrigation condition, the  Torbat-e-jam population had highest total phenol content (86.66 mg gallic acid per gram of methanolic extract) under this condition. In both irrigation conditions, the evaluated populations exhibited suitable amounts of picocrocin, safranal, phenol and antioxidant properties which can be considered to be of use for us in the food, pharmaceutical and chemical industries.

Biological stresses such as drought affect the production of secondary metabolites, especially plant sterols (phytosterols). Among the phytoestrols found in pumpkin seeds, betasitosterol is one of the most important components which also have many medicinal properties. In this study, the effect of five levels of drought stress on seed oil production and its phytosterols was studied in three genotypes and Styriaca variety of pumpkin (Cucurbita pepo L.). Analysis of phytosterols using GC/MS showed that increasing drought stress had a negative effect on oil production from pumpkin ripe seeds, but oil phytosterols, especially betasitosterol, increased and this increase was higher in Styriaca than other genotypes. To confirm these results, the seeds were harvested 15-30 days after flowering and the expression of SQS, PP2A, SMT2, ERG26 and Cycloartenol synthase genes involved in the phytosterol biosynthesis pathway was investigated. The results indicated that, among the different levels of drought stress and genes studied, highest expression level was observed at the rainfed level and at that time, betasitosterol and stigmasterol pathway had the main activity in steroid biosynthesis pathway in pumpkin.

In order to investigate the effects of growth regulators on yield and agronomical characteristics of saffron (Crocus sativus L.), an experiment was conducted in a randomized complete block design in the research greenhouse of Faculty of Agriculture, University of Zanjan. Experimental treatments included corms priming with gibberellic acid (GA) (250, 500 and 750μM), salicylic acid (SA) (700, 1400 and 2100μM), paclobutrazol (PBZ) (50, 100 and 150μM), chlormequat chloride (CCC) (500, 1000 and 1500 μM), hydropriming (HP) (distilled water), and control (treatment without any growth regulator). Among the treatments, the effect of GA was more pronounced than other growth regulators, so that the highest dry yield of flower and stigma was observed in GA treatment, especially at 500-μM level. CCC and PBZ caused the lowest flower and stigma yield and the highest amount of chlorophyll pigments compared to other treatments. In contrast, the use of GA and SA reduced the chlorophyll content. HP treatment did not show any significant difference with control. SA treatment increased safranal (perfume) and crocin (color) of the stigmas. The highest effect on picrocrocin (flavor) was obtained in CCC treatment.

In this study, the effect of equal matric and osmotic potentials was investigated separately and simultaneously on water uptake and yield of corn. A factorial experiment with two factors; potential type (osmotic, matric and combined) and potential levels (-0.46, -1.12, -1.91, and -3.63 bar) was performed on the basis of completely randomized design with 4 replications in greenhouse conditions. Increasing in osmotic stress (from -0.46 to -3.63 bar) resulted a reduction in water uptake by 36.6%. Potential reduction reduced root dry mater 40 and 36.6% in osmotic and combined potential treatments, respectively. Slight drought stress increased root dry matter by %26. Among the treatments and potential levels, the highest water use efficiency was observed with 1.12 g/l for the potential level of -1.12 bar in the combined stress. The results showed under the same levels of osmotic and matric potential, the salinity stress causes more damage to plant growth with decreasing water uptake. At low potential levels (-0.46 to -1.12) of combined treatments, the partially irrigation system increases water use efficiency, due to relative improvement in root growth. At low potential level (-3.63 bar) of combined treatment (with equal suction at two sides of the root), the plant uptakes less water than the condition where total root experiences the same level of potential by salinity. At least for low salinity leves, the osmotic and matric potential values cannot be considered as two additive parameters; On the other hand, the sumation of them cannot show the real stress conditions of the root environment. The results of such studies can be used to accurately manage the quantity and quality of irrigation water under the salinity and drought stress in arid and semi-arid regions.

With increasing global warming, drought stress and salinity are considered as one of the most important problems in agriculture and soil management. These stresses will change the uptake of nutrients by the plant. In the nature, the plant is under salinity and drought in same time. However, few studies have been carried out on the contribution of each stresses to nutrient variation under mixed treatment. Therefore, this study examines the effects of same amounts of matric and osmotic potentials on variation in some nutrients and their ratios under full and partial irrigation systems in corn leaves and roots.

Experiments with two factors consist of potential-type (osmotic, matric, and combined) and potential levels at four levels (-0.46, -1.12, -1.91, -3.63) performed on the basis of completely randomized design in greenhouse conditions. In order to apply salinity and drought stress to two parts of the root of a plant, a separator structure was used to separate the root into two parts in the pot. To fix the suction of the matric and pots drainage, a handmade tensiometer was used.

The study of variations in nutrient concentration in leaves showed that the partial root irrigation system in the mixed treatment reduced by 11 and 7% concentration of N at levels of -1.12 and -19.9 bar, respectively, compared with the matric potential treatment. Also, P concentration of leaf in mixed treatment compared to the osmotic and matric potentials treatment respectively at level -1.91 bar was increased by 87% and 83%, respectively, and at level -3.63 bar 91% and 95%, respectively. However, the concentration of all nutrients studied in the root was influenced by type, potential level and interaction of these two factors except for phosphorus. In partial irrigation system, the significant variations of N, K, K / N and K / Ca in the section were affected by osmotic potential and total Ca and Mg in the section of matric potential compared with to full irrigation root.

This study showed that in high levels of osmotic and matrix potential in mixed treatments, due to the presence of sufficient water in half of the root, the changes in the nutritional elements are low compared to the isolated osmotic and matric treatments and increase with the potential reduction of these changes. In this case, the most variations in the elements are related to the salinity part the mixed treatment. Therefore, the reduction of the osmotic potential level in the root portion should be accompanied by increased matric potential in the other part of the root, so that it can reduce the nutritional balance of the plant.

For investigation the impact of drought stress on several Agronomic, physiological, yield and yield component in various varieties of medicinal pumpkin (Cucurbita pepo L.), an experiment was conducted as a factorial based on complete randomized block design with three replications at Agricultural and Natural Resources Research Center of Zanjan during spring and summer of 2015. The effects of water stress in five levels ( S1 or control, S2 or irrigation in 75% of Field Capacity (FC), S3 or irrigation in 50% FC, S4 or irrigation in 25% FC and S5 or without irrigation (dry farming )) and four varieties that cultured in multiple points of Iran ( V1 or unknown variety from khoy, V2 or unknown variety from Isfahan, V3 or unknown variety from Zanjan and V4 or var. Styriaca) were considered. The results showed that the effects of drought stress on traits was significant and cause decrease in all investigated parameters. However, the highest grain and fruit yield were obtained in control treatment or full irrigation in Styriaca variety with 825 and 15430 kg.ha-1, respectively and lowest were obtained from Isfahan variety in dry farming condition with 680 and 2758 kg.ha-1 respectively. In the presence of moderate drought stress, the highest rate of photosynthesis, transpiration, stomatal conductance and relative water content was for Isfahan unknown variety and seems that it is a good candidate variety for areas with mild stress.

  Cucurbita pepo belongs to the Cucurbitaceae family. Drought is one of the main abiotic stresses which is limited planting in most farming land in Iran that limits produce agriculture products. Development of crops for enhanced drought resistance, among other things, requires the knowledge of physiological mechanisms and genetic control of the contributing traits at different plant developmental stages. For investigation the impact of duration of drought stress on several physiological parameters in four varieties of medicinal pumpkin (Cucurbita pepo L.), an experiment was conducted as spilt – spilt plot based on a complete randomized block design (RCBD) with three replications. The effects of water stress in five levels (S1 or control, S2 or irrigation in 75% of Field Capacity (FC), S3 or irrigation in 50% FC, S4 or irrigation in 25% FC and S5 or without irrigation (rainfed)) as main plot, four varieties that cultured in multiple points of Iran ((V1 or unknown variety from Khoy, V2 or unknown variety from Isfahan, V3 or unknown variety from Zanjan and V4 or var. Styriaca) as sub plot and during of drought stress in twelve weeks as sub subplot were considered. But for facility in analysis, only four weeks were considered. The results showed that for almost parameters, four varieties were not showed statistically differences. Since, pumpkin is not native plant in Iran, it seems these varieties have a similar genetically origin. Our results show that with increasing watering stress, seed and fruit yield and their component were reduced. Findings indicated that Relative Water Content (RWC) decreased with drought stress increasing that was agree with previous studies. In our study, total exchange gas in all four varieties when they were imposed to drought stress were changed. One of the first responses of plants to drought is stomatal closure, restricting gas exchange between the atmosphere and the inside of the leaf. The drought stress resulted in reduction of chlorophyll a, b and carotenoids. A reason for chlorophyll content reduction is that drought stress enhances the production of reactive oxygen species (ROS) such asO2 − andH2O2 that can lead to lipid peroxidation and, consequently, chlorophyll degradation (Tatrai et al., 2016). Proline contents were increased under drought stress. The proline accumulation during the stress helps the plant to reduce the oxidative destruction and it is necessary to be survived under drought stress (Verbruggen and Hermans, 2008). Our study revealed that with increasing drought stress, seed protein (%) was increased. Soluble sugar with increasing drought stress was increased. Increasing of soluble sugars during stress can be attributed to the stop of growth or synthesis in these compounds from non-photosynthesis routes (Ghorbanali, 2003). Results showed that in most traits such as fruit yield, RWC, photosynthesis and transpiration rate, stomatal conductance and carotenoids, under normal condition ‘Isfahan’ unknown variety, had the better status between other varieties in control condition. It might be stated that with increasing duration and levels of drought stress, due to keep photosynthetically conditions reduction in this variety in most traits was less than other varieties. Since, there were no significantly drought stress effects on varieties, thus we can say that “Isfahan” unknown variety is superior variety in the experiment and this variety has the capacity to introduced in Zanjan region.

Plants are using various mechanisms at the molecular, biochemical and physiological levels for resistance to cold stress. These responses are controlled via stress phytohormones. One of the main hormones is jasmonic acid that plays main roles in various stress, however, there are few studies of the effects of the hormones on cold stress. Its signaling pathway in response to low temperature has remained unknown. In this study, a weighted gene co-expression network was utilized to determine the effect of jasmonic acid in response to cold by using microarray data at Arabidopsis. The 15 gene groups were found that each one controls a special process. Photosynthesis and carbohydrate catabolic and metabolic processes are the most important biological processes in response to the two stimuli. Gene co-expression network displays that transcription factors play main roles in the processes. According to results, two transcription factors ERF13 and ORA47 candidate for relationship between jasmonic acid and cold tolerance and possibly intermediate between CBF1 and CBF2 transcription factors and regulatory proteins in the jasmonic acid signal transduction pathway, tify family. Three transcription factors (HY5, bHLH15 and PIF3) also cooperate in the signaling pathway to respond to low temperature in plants.

To assess the genetic diversity of recombinant inbred lines of barley(Hordeum vulgare L.) under two non-stress and drought stress conditions in seedling stage, two populations,Vada×Susptrit (V×S) with 112 RILs and Cebada Capa×Susptrit (CC×S) with 89 RILs, were studied in completely randomized design with two replication in greenhouse. The traits studied were four physiological traits including leaf relative water content, leaf chlorophyll content, shoot dry weight and leaf temprature.Under drought stress conditions, leaf chlorophyll content also measured in three soil water conditions (%50, %30 and %20 field capasity). According to cluster analysis in both populations, V×S and CC×S, the genotypes were grouped in five and four clustersunder normal and drought stress conditions, respectively. Discrimnant function analysis powerfully confirmed the results of cluster analysis in two populations under both experimental conditions. In the population V×S, the first and second discriminant functions with eigen values significant and more than one justified %78.2 and %93.4 of the total variance under normal and drought stress conditions, respectively.In the population CC×S, the first and second functions with eigen values more than one also justified %78.8 and %90 of the total variationsunder non-stress and drought stress conditions, respectively. Additionally, grouping the studied lines in both populations under two conditions was investigated and confirmed by the Mahalanobis distance. The results of this study showed that discrimnant function analysis is a very usfull multivariate statistical method for evaluating and confirmingthe grouping of barley genotypes under normal and drought stress conditions. The results of current research also showed that there is ahigh and considerable variation in both populations under both conditions, so that these populations can be utilized for mapping quantitative trait loci related to drought tolerance in barley using molecular markers.

In current study, a conceptual mathematic model is developed to determine the relationship between plant response factor to water (ky) and soil critical moisture (c) that below c, plant is under stress. The evaluation of model performance was done using a set of experimental data from a green-house trial. The results showed that for a given Ky, relative plant yield (Yr) is linearly reduced by decreasing the differences soil moisture from c (c-). The greater sensitivity of plant type or growth stage to water deficit (higher Ky values) caused more slope of linear relationship between Yr and (c-). In the other words, it can be assigned more allowable depletion coefficient for the plants with low Ky values. Moreover, for a given Yr, plant sensitivity is exponentially increased by the reduction of soil moisture. In addition to confirm the model results, exprimental observations showed that the critical moisture of clay loam soil for both soil was 0.28 cm3 cm-3, while the c values of sandy loam soil for wheat and canola ware 0.21 and 0.195 cm3 cm-3, respectively. Soil allowable depletion coefficient for wheat in both soils was obtained about 0.35. Whereas, soil allowable depletion coefficient for canola in sandy loam soil (F=0.44) was more than clay loam soil (F=0.38).