relative water content

In order to study the effects of nitrogen and biofertilizers on the trend of changes in chlorophyll fluorescence components, grain yield and some traits of wheat (Triticum aestivum L.) var. Chamran, an experiment as factorial, was conducted based on a randomized complete block design with three replications at the research farm of the Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabil, in 2021–2022. The experimental factors included the application of biofertilizer at eight levels (control, Azotobacter, Glomus moseae, Glomus intradices, Glomus moseae with Azotobacter, Glomus intradices with Azotobacter, Glomus moseae and Glomus intradices, Glomus moseae and Glomus intradices with Azotobacter) and nitrogen rates at three levels (no application of nitrogen as a control, application of 100 and 200 kg urea/ha). The results showed that Azotobacter sp. and Mycorrhiza (Glomus moseae and Glomus intradices) and 200 kg urea/ha had the lowest electrical conductivity and minimum fluorescence. Biofertilizer application (Azotobacter, Glomus moseae and intradices) increased the chlorophyll index (56.31%), relative water content (63.03%), variable fluorescence (101.86%), maximum fluorescence (38.5%), quantum yield (45.77%) and grain yield (36.68%) in comparison with no application of nitrogen and biofertilizers. The maximum nitrogen use efficiency was observed in the application of 100 kg nitrogen/ha. Based on the results of this study, it seems that the application of biofertilizers (Azotobacter and Mycorrhiza) and 200 kg urea/ha by improving chlorophyll fluorescence components and some physiological traits such as electrical conductivity and relative water content increased the grain yield of wheat by about 36.6% in comparison with control (no application of nitrogen and biofertilizers).

The use of plant symbiosis with arbuscular mycorrhizal fungi (AMF) and Plant-growth-promoting rhizobacteria (PGPR) is one of the ways to reduce drought stress that has recently been used in agriculture. In the present study, the response of lemon balm (Melissa officinalis L.) plants to microbial inoculation of plant growth-promoting rhizobacteria (PGPR, Azospirillum brasilense) and arbuscular mycorrhizal fungus (AMF, Glomus mosseae) and co-inoculation (AMF+PGPR) under well-irrigated (100% field capacity) or drought stress (50% field capacity) conditions were investigated. This study was conducted in 2020 in the greenhouse of Ayatollah Amoli Branch, Islamic Azad University, Amol, Iran as a factorial experiment based on a completely randomized design with five replications. The results of the present study showed that drought stress by reducing the relative water content (RWC, 17.8%), declined transpiration rate (E, 62.2%), stomatal conductance (gs, 36.8%), intercellular CO2 concentration (Ci, 22.5%), and net photosynthesis (Pn, 48.5%) of the plant compared to control plants. Drought stress also induced oxidative stress by increasing the accumulation of hydrogen peroxide (2.1-fold) and methylglyoxal (2-fold), resulting in damage to bio-membranes and photosynthetic apparatus and reduced growth of lemon balm. However, microbial inoculation, especially co-inoculation of PGPR and AMF, by improving the proline content and RWC, restored Ci, E, gs and Pn under drought stress. Microbial treatments by increasing the activity of antioxidant enzymes and the glyoxalase system reduced the level of hydrogen peroxide and methylglyoxal and alleviated drought stress-induced oxidative stress, which increased the growth of lemon balm under drought stress by protecting bio-membranes and photosynthetic pigments. Therefore, the results showed that the application of G. mosseae and A. brasilense alleviated the negative effects of drought stress on lemon balm.

To study the effects of stress modulators (vermicompost, mycorrhiza, and foliar application of putrescine and nano zinc oxide) on chlorophyll fluorescence indices and some physiological traits of barley under water limitation conditions, a factorial experiment was conducted based on randomized complete block design with three replications at the research greenhouse of the Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili in 2022. The experiment factors included irrigation levels (full irrigation as a control, irrigation withholding at 50% of booting and heading stages, as moderate and severe water limitation respectively equivalent to BBCH 43 and 55), application of bio-organic fertilizers in four levels (no application as a control, application of vermicompost, mycorrhiza, both application of vermicompost and mycorrhiza), foliar spraying of putrescine and nano zinc oxide in four levels (foliar spraying with water as a control, foliar spraying 0.4 g.L-1 nano zinc oxide, 0.8 mM putrescine, foliar spraying zinc, and putrescine). The results showed that application of stress modulators (vermicompost, mycorrhizal, zinc and putrescine) under severe water limitation (irrigation withholding at 50% of booting) increased chlorophyll index (34.06%), flag leaf nitrogen index (24.19%), maximum fluorescence (77.73%), quantum yield (80.38%), stomatal conductance (62.88%) and relative water content (50.99%) in compared to the no application of stress modulators in the same level from irrigation levels. Also under severe water limitation, the lowest minimum fluorescence (137.8) and electrical conductivity (90.07 μS.m-1) were obtained at the application of stress modulators (vermicompost, mycorrhiza, and foliar application of putrescine and nano zinc oxide). Based on the results of this study, irrigation withholding at 50% of booting and no application of stress modulators decreased 25% grain yield of barley compared to the application of stress modulators in the same level of irrigation levels and application of stress modulators were able to compensate for part of this reduction in grain yield.

Regarding to water deficit issue in our country, it is essential to find innovative methods to alleviate the adverse effects of drought stress on plants. Therefore, a pot experiment was conducted to evaluate the effect of 3 levels of irrigation intervals (1, 2, 3 days) and 5 levels of CuO NPs (0, 2.5, 5, 10, 20 mg/L) on fennel (Foeniculum vulgare Mill.). Results showed that increasing irrigation intervals reduced fresh and dry weights of plants, total chlorophyll and carotenoid contents, and relative water content (RWC) and increased lipid peroxidation, proline content, and the activities of ascorbate peroxidase (APX) and catalase (CAT) enzymes. The foliar application of CuO NPs influenced all the above-mentioned parameters in a dose-dependent manner. Foliar application of CuO NPs till 10 mg/L improved plant growth, the content of photosynthetic pigments, RWC, and proline accumulation, and reduced lipid peroxidation level through up-regulation of antioxidant enzymes. In contrast, 20 mg/L CuO NPs, decreased growth parameters and chlorophyll content and significantly increased lipid peroxidation under both normal and drought stress conditions, which suggests the high dose of CuO NPs induced stressful situations for the plants. Therefore, low concentrations of CuO NPs moderated water deficit-induced osmotic and oxidative stresses but, the application of high concentrations of CuO NPs was not recommended for fennel cultivation.

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

In order to investigate the effect of cycocel and micronutrient consumption on yield, physiological traits, and antioxidant content of maize under low irrigation conditions at the end of the season, a split factorial experiment was carried out based on a randomized complete block design with four replications in Safiabad Agriculture Research Center in Dezful during two cropping years 2017-18 and 2018-19. The main treatment included water stress with three levels control (without water stress), water stress in female flower formation stage and water stress in grain swelling stage. Also, foliar application of cycocel at three levels of control (no use of cycocel), 442.5 ppm, and 885 ppm and three levels of micronutrient fertilizers, namely control (no fertilizer application), foliar application of 1000 g. ha-1, and foliar application of 1500 g. ha-1 were considered as the sub-factors. Results of the combined ANOVA showed that the interaction of the effects of year, stress, micronutrient, and cycocel on relative water content, proline and grain yield and also the interaction of the effects of stress, micronutrient, and cycocel on hydrogen peroxide, glutathione peroxidase, and soluble proteins were statistically significant (p≤0.01). The results also showed that the highest activity of superoxide dismutase enzyme was obtained under stress conditions at the grain swelling stage, which showed an increase by about 37% compared to the irrigation treatment under optimal conditions. Foliar application of 1500 g. ha-1 micronutrient and 885 ppm cycocel in non-stress conditions increased the average grain yield (11500 kg. ha-1) in the second year by about 85% compared to stressed condition at grain swelling stage and no application of micronutrient and cycocel. In general, to increase grain yield under optimal irrigation conditions and reduce the drop in stress conditions, growth regulators such as cycocel with a concentration of 885 ppm and micronutrient foliar application at 1500 g. ha-1 are recommended.

Soil application of farmyard manures and moisture-absorbing materials such as natural zeolite is considered a simple and cheap way to conserve soil moisture in arid areas and light soils. To study the effect of two soil amendments on the physiological properties of “Bidaneh Sefid” grapevines under drought stress, an experiment was conducted in factorial based on a randomized block design in the research vineyard of Malayer University, Hamadan, Iran during the 2022 and 2023 growing seasons. The treatments included two levels of irrigation cycle (7 and 21 d intervals) and four levels of soil amendments (control, 12 kg zeolite vine-1, 15 kg sheep manure vine-1, a combination of 12 kg zeolite + 15 kg sheep manure vine-1). Results showed that the drought stress led to a decrease in chlorophyll content, leaf relative water content, and leaf water potential. Drought stress also led to an increase in electrolyte leakage and the activity of antioxidant enzymes. Application of farmyard manure and zeolite moderated all the investigated indicators, due to their ability to absorb and retain water in the soil. The results of the study showed that it is possible to mitigate the adverse effects of drought stress on grapevine by retaining the moisture of light soils by the application of natural zeolite, alone or in combination with farmyard manure.

Drought stress, as the most important environmental stress, severely disrupts plant growth and limits production and yield more than any other environmental factor. Investigation of the role of drought stress conditions on plant morphological, physiological and photosynthesis characteristics may provide a tool to understand the basic drought resistance. To investigate the drought tolerance of Iranian and foreign grapevines (Vitis vinifera L.) cultivars, A pot experiment was conducted with 5 replications, and 20 Iranian and foreign rooted grape cultivars exposure with two treatments of 90 (control) and 50 (drought stress) water requirement. Iranian grape cultivars included Rashe, Bidane Sefid, Bidane Ghermez, Yaghoti, Fakhri, Khalili Sefid, Ghezel Ouzom, Asgari, Gazandai, Gachi Amjagi, Tabraze Ghermez, Tabraze Sefid, Laal, Hosseini and Shirazi and foreign cultivars including Black Seedless, Flame Seedless, Perlette, Ruby Seedless and Torkaman 4. Based on results, after three months of drought stress, the interaction of drought stress and cultivar was significant for leaf number, leaf area, current branch length, internode length, root length, root volume, root fresh weight and electrolyte leakage and not significant for stem diameter, root dry weight and relative water content. In general, despite the increase in chlorophyll a, b, total and carotenoids in some cultivars, these physiological characteristics decreased by 29.43, 20.47, 27.47 and 22.15%, respectively under drought stress. Photosynthetic traits such as photosynthesis, transpiration, stomatal conductance and intercellular CO2 concentration were also significantly affected by drought stress and reduced by 39.11, 42.36, 54.98 and 30.33% in drought conditions. Rashe, Khalili Sefid, Yaghoti and Laal cultivars showed good resistance to drought stress conditions, whereas Fakhri, Shirazi, Bidane Sefid, Gazandai and Gachi Amjagi cultivars were sensitive to drought stress.

In order to investigate the effects of nanoparticles) nano Fe-Si oxide) and biofertilizers (Azospirillum lipoferum and Pseudomonas putida) on chlorophyll fluorescence components and some physiological traits of triticale at different levels of irrigation, an experimental as the factorial study was conducted based on randomized complete block design with three replications. The studied factors included three levels of irrigation (full irrigation as control, irrigation withholding at 50% of booting and heading stages as severe, and moderate water limitation, respectively), application of biofertilizers (Azospirillum  lipoferum and Pseudomonas putida) in four levels, and nanoparticles foliar application (nano iron oxide and nano silicon oxide) at four levels. Both applications of plant growth-promoting rhizobacteria and nanoparticle foliar application under full irrigation increased chlorophyll index (50.23%), relative water content (43.97%), stomatal conductance (36.78%), quantum yield (47.38%), maximum fluorescence (34.84%), variable fluorescence (98.49%), and grain yield (43.28%) in comparison to no application of biofertilizers and nanoparticles under irrigation withholding at booting stage. Both applications of plant growth-promoting rhizobacteria and nanoparticles increased the chlorophyll index, relative water content, stomatal conductance, quantum yield, maximum fluorescence, variable fluorescence and grain yield in both levels of full irrigation and severe water limitation, but decreased electrolyte leakage and minimum fluorescence. In addition, severe water limitation or irrigation withholding at the booting stage increased chlorophyll index (7.74%), relative water content (10.99%), stomatal conductance (22.46%), quantum yield (15.2%), maximum fluorescence (26.54%), variable fluorescence (75.61%) and grain yield (28.59%) in comparison to no application of biofertilizers and nanoparticles at the same irrigation level. Generally, the application of biofertilizers and nanoparticles showed a better performance at different irrigation levels due to the improvement of physiological traits.
Triticale is a human-made crop, being a hybrid by cross-fertilization of wheat (Triticum spp.) and rye (Secale spp.). In general, triticale combines the high yield potential of wheat with the biotic and abiotic stress tolerance of rye, making it more suitable for production in marginal areas (acidic, saline, or soils with heavy metal toxicity) (Cantale et al. 2016). In arid and semi-arid regions, drought stress as the main factor and salinity stress as a secondary factor decrease plant growth and yield. Water limitation can damage pigments and plastids, and educe chlorophyll index, stomatal conductance, quantum yield, and relative water content. Several strategies have been developed in order to decrease the toxic effects caused by environmental stresses on plant growth. Among them, the use of bio-fertilizers such as plant growth-promoting rhizobacteria (PGPR) and also nanoparticles such as nano iron-silicon oxide plays a very important role in yield improvement. Inoculation of plants with native suitable microorganisms may decrease the deleterious effects of environmental stresses and increase stress resistance of plants by various mechanisms, including synthesis of phytohormones such as auxins, cytokinin and gibberellins, solubilization of minerals like phosphorus, production of siderophores and increase in nutrient uptake. There is little information on the effects of nanoparticles and biofertilizers on chlorophyll fluorescence components and some physiological traits of triticale at different irrigation levels. Therefore, the objective of the present study was to evaluate the effect of nanoparticles (nano Fe-Si oxide) and biofertilizers (Azospirillum  lipoferum and  Pseudomonas putida) on chlorophyll fluorescence components and some physiological traits of triticale at different levels of irrigation.
 
An experiment as factorial was conducted based on a randomized complete block design with three replications at the research farm of the Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili in 2021. The experimental factors included irrigation in three levels (full irrigation as control, irrigation withholding at 50% of booting and heading stages as severe, and moderate water limitation, respectively (BBCH 43 and 55 respectively), the application of biofertilizers in four levels (no application as control, application of Azospirillum, Pseudomonas, both application Azospirillum + Pseudomonas) and nanoparticles foliar application at four levels (foliar application with water as control, nano iron oxide foliar application (1 g.L-1), nano silicon oxide (50 mg.L-1), both application nano iron-silicon oxide). Psedomunas and Azospirillum were isolated from the rhizospheres of wheat by the Research Institute of Soil and Water, Tehran, Iran. For inoculation, seeds were coated with gum Arabic as an adhesive and rolled into the suspension of bacteria until uniformly coated. The strains and cell densities of microorganisms used as PGPR in this experiment were 1×108 colony forming units (CFU). In each plot, there were 5 rows with 2 m long. In each experimental plot, two beside rows and 0.5 m from the beginning and end of planting lines were removed as margin, and measurements were done on 0.2 m2 for grain yield. The used nano silicon-iron oxide had an average particle size of less than 30 nm and the special surface of particles was more than 30 m2.g-1. They were the product of Nanomaterial US Research which was provided by Pishgaman Nanomaterials Company of Iran. Nano silicon oxide and nano silicon oxide powder were added to deionized water and placed on ultrasonic equipment (100 W and 40 kHz) on a shaker for better solution. Foliar application of nano silicon and nano iron oxide was done in two stages of period growth BBCH 21 and 30. Chlorophyll Index was calculated by a chlorophyll meter (SPAD-502; Konica Minolta Sensing, Inc., Japan). RWC and EL were measured according to the method of Kostopoulou et al. (2010) and Farooq and Azam (2006), respectively. Quantum yield was measured on flag leaves by the uppermost fool expanded leaf using a fluorometer (chlorophyll fluorometer; Optic Science-OS-30 U.S.A.). Analysis of variance and mean comparisons were performed using software package SAS v9.12. The main effects and interactions were compared by LSD (least significant difference) test at the 0.05 probability level, using the SAS version 9.1. 
 
The results showed that both applications of plant growth-promoting rhizobacteria and nanoparticle foliar application under full irrigation increased chlorophyll index (50.23%), relative water content (43.97%), stomatal conductance (36.78%), quantum yield (47.38%), maximum fluorescence (34.84%), variable fluorescence (98.49%), and grain yield (43.28%) in comparison to no application of biofertilizers and nanoparticles under irrigation withholding at booting stage. Both applications of plant growth-promoting rhizobacteria and nanoparticles increased chlorophyll index, relative water content, stomatal conductance, quantum yield, maximum fluorescence, variable fluorescence, and grain yield at both levels of full irrigation and severe water limitation, but decreased electrolyte leakage and minimum fluorescence. In addition, severe water limitation or irrigation withholding at the booting stage increased chlorophyll index (7.74%), relative water content (10.99%), stomatal conductance (22.46%), quantum yield (15.2%), maximum fluorescence (26.54%), variable fluorescence (75.61%), and grain yield (28.59%) in comparison to no application of biofertilizers and nanoparticles at the same level from irrigation levels.
 
Based on the results of the study, the application of biofertilizers and nanoparticles showed a better performance at different irrigation levels due to the improvement of physiological traits. In other words, the effects of the simultaneous application of PGPR and nanoparticle inoculation are more positive than the single application of PGPB and nanoparticles. Therefore, one of the suitable methods to improve plants' resistance to environmental stress is the application of PGPB and nanoparticles, which play a very important role in yield and growth improvement.

Due to climate changes and Deficiency of water resources, as well as the importance of cultivating ornamental plants in green space, in order to better water management, an experiment to investigate the effect of water deficit sress and foliar application of different concentrations of selenium on some morphophysiological and biochemical characteristics of Scarlet sage, in factorial experiment based on a completely randomized design with three levels of water deficit stress (90 (control), 80 and 70% of field capacity) and four levels of sodium selenate (0, 0.5 and 1.5 μM) were performed in greenhouse conditions. Experiment results showed that water deficit stress decreased plant height, leaf area, flower longevity, relative leaf water content and increased electrolyte leakage and malondialdehyde concentration. Application of selenium at concentrations of 0.5 and 1 μM by increasing the activity of catalase, ascorbate peroxidase and peroxidase enzymes increases plant height, leaf area, flower longevity, relative leaf water content and reduces electrolyte leakage, malondialdehyde concentration and also increases relative it was photosynthesized at the concentration of pigments but at a concentration of 1.5 μM had a negative effect on the mentioned properties. In general, the results showed that under water deficit stress has a detrimental effects on plants growth and development. Selenium in water deficit stress and non-stress conditions at low concentrations improved the vegetative and reproductive growth of plants but at higher concentrations had a negative effect on these parameters.

Lack of rainfall and rising temperatures have caused problems in the agricultural crop cultivation in many areas. Grapevine is one of the most important economic products in horticulture. Due to the importance of grapes as important economic products in horticulture, identification and use of resistant cultivars to drought stress is one of the basic steps and the important goals this plant breeding programs. This research carried out in factorial experiment in randomized complete design with three replications in 2020. Experimental factors was include different levels of drought stress (level four 100, 75, 50 and 25% of water requirement) and grapvine cultivars (Gharashiliq (Ga), Rasmi (Ra), Aghshiliq (Ag), Copake Bogan (Co), Tukilgen (Tu) , Khalili (Kh)). The results of this study showed that with increasing drought stress level in 6 grape cultivars, plant growth parameters, relative leaf water content, photosynthetic pigment content decreased significantly (p <0.01), that the greatest decrease was observed at the stress level of 25% water requirement. Also, increasing drought stress levels the electrolyte leakage, malondialdehyde, total soluble sugars, proline and antioxidant enzymes activity content increased in more cultivars, significantly (p <0.01). Increasing drought stress to 25% field capacity, the highest and lowest leaf area decrease percentage compared to the control were observed in Copake Bogan (68%) and Gharashilig (45%) cultivars, respectively. Among the studied cultivars, the highest and lowest ion leakage content were observed in Aghshilig and Gharashilig cultivars, which had 36% and 32.8%, respectively. The highest proline content was obtained in Gharashilig cultivar (0.14 µmol g-1 FW) and the lowest was obtained in Copake Bogan cultivar (0.067 µmol g-1 FW). Also, The highest and lowest catalase enzyme content among the 6 studied grape cultivars were obtained in Gharashilig cultivar (3.02 µmol g-1 FW.min) and Copake Bogan (1.41 µmol g-1 FW.min). The highest peroxidase enzyme content was obtained in Tukilgen (5.86 µmol g-1 FW.min) and the lowest content in Rasmi (1.39 µmol g-1 FW.min) cultivar. The results showed, Aghshiligh and Copake Bogan cultivars were drought-sensitive and Garashiligh cultivars drought-tolerant and the rest are semi-drought sensitive cultivars.

Recent droughts, in addition to creating drought stress, have caused the phenomenon of aerosols, especially in the west of the country. The effect of drought stress and aerosols on the physiological characteristics of soybean (Glysin max L.) Kosar cultivar was investigated in an experiment based on a randomized complete block design as split plots with 4 replications in summer cultivation for two years. Drought stress through irrigation after 60 (optimal irrigation), 90 and 120 mm evaporation from Class A evaporation pan as the main factor and spraying of aerosols in three levels of non-application (control) and application of 50 and 100 mg in cubic meters of air were placed in subplots as simulations. The results showed that severe drought stress significantly reduced the amount of chlorophylls a and b, catalase of shoots and roots. The amount of light of the canopy floor and the relative water content of the flag leaf (from 89 to 70%), plant height, yield components and grain yield (from 2653 to 1167 kg per hectare) compared to the control treatment, but soluble sugars, proline content, shoot and root peroxidase and leaf temperature (from 18.4 to 27.6 °C) increased significantly. Although the effect of aerosols on any of the traits was not significant, but with increasing the concentration of aerosols, grain yield decreased linearly and proline content increased linearly. Overall, it was found that drought stress significantly reduced soybean production, but low aerosols settling on soybean leaves did not cause serious damage to the plant photosynthetic system and ultimately seed production due to leaves waxy nature.

In order to investigate the effect of drought stress and nano-TiO2 and salicylic acid foliar application on some physiological traits of Echinaceae purpurea under water, an experiment was conducted in split plot factorial based on RCBD in three replications at the Research Station of the Islamic Azad University, Tabriz Branch, during growing seasons of 2017-2018. The main factors were water deficit stress at three levels of 50, 75, and 100% filed capacity, thefactorial combination of nano-TiO2 (n-TiO2) foliar application at two levels (0.02 and 0.04%) and salicylic acid foliar application at two levels (0.02 and 0.04%), and also distilled water foliar application as control treatment. Findingsshowed a significant effect of water deficit stress on relative water content (RWC) and proline (p≤0.01). Also, interaction of the effects of water deficit stress and nano-TiO2 and salicylic acid foliar application on Chl. b, total Chl., and hydrogen peroxide contents was significant (p≤0.01). Application of water deficit stress treatment up to 50% FC increased proline content by 40% and reduced RWC by 10% compared to complete irrigation (100% FC). Furthermore, 0.04% n-TiO2 and 0.04% SA foliar application increased hydrogen peroxide content by 50% compared to complete irrigation group and the control. The maximum total Chl. Contents of leaves was obtained under 100% FC irrigation and and 0.04% n-TiO2 and 0.02% SA foliar application showing 79.52% increase compared to 100% FC irrigation and no foliar application.

In order to study the effects of supplementary irrigation and seed inoculation by bio fertilizer on yield and some physiological traits of rainfed wheat (Rasad cultivar), a factorial experiment was conducted based on randomized complete block design with three replications in Agricultural Research Station of Ardabil in 2016. The factors experimental were included supplementary irrigation at three levels, once supplementary irrigation at booting stage (I1), once supplementary irrigation at heading (I2) and no irrigation as rain fed (I3), and biofertilizers in four levels without application of bio fertilizers as control (B1), seed inoculation with Azospirilum (B2), mycorrhizal application (B3), both application mycorrhizal and Azospirilum (B4). Means comparison showed that application of both bio fertilizers (mycorrhiza and Azosprilium) and once supplementary irrigation at booting stage and once supplementary irrigation at heading increased the grain yield about 35.27 and 28.9% respectively in comparison with application of bio fertilizers under rainfed conditions. Both application mycorrhiza and Azosprilium and once supplementary irrigation at booting stage increased maximum fluorescence (Fm), variable fluorescence (Fv), chlorophyll index and relative water content of flag leaf in comparison with no application of bio fertilizers under rainfed condition. Rainfed conditions increased electrical conductivity and minimum fluorescence (F0).

During the last decades, it has been sanctioned the number of regulations in relation to the control of population in Iran which could illustrate the approach of legislative policy of the country towards the issue of population. In this writing, the legislative policy of population has been investigated from two aspects. First, Iran’s legislative policy has never had a clear orientation related to the increase, decrease or the balance of population and second, the regulation observant on the control of population is considered as one of the only social elements effective on controlling the rate of population growth and the other factors such as economic and social factors as well as the cultural attitudes, the status of environment along with the natural sources effective on the increase or decrease of this rate. According to this article, the legislative policy is in the need of consistency in this regard and it could not be necessarily accepted that the legal system is considered as the main element in the rate of population growth. Hence, the approval of the impact of legal system on the increase or decrease of population would be in need of evaluating the regulatory works sanctioned in the domains of population while this evaluation has been undone hitherto. Moreover, the most significant element effective on the fulfillment of the objectives of a regulation is the possession of the executive guaranty and the policies concerning the control of population are not of sufficient executive guaranty though. The recommended strategy of this article is the necessity of gradual movement of the legal system towards the fulfillment of population balance instead of statistical controlling the population indexes.

Tuberose flower is one of the aromatic bulbous flowers in tropical and subtropical regions. In order to study the effects of exogenous melatonin (M) on some physiological parameters of cut flower Tuberose, an experiment was performed base on a completely randomized design(CRD) with three replicates and 15 flower per replication. Melatonin (in concentrations of 0 and 250 μL.L-1 for 4 hours) was used as pulse-treatment. Melatonin treatment compared to the control prevented the decrease of Relative water content (RWC), the increase of Electrolyte leakage (EL), and malondialdehyde (MDA) concentrations in the tissues (leaves and petals). In addition, melatonin increased the amount of ascorbate peroxidase (APX) and peroxidase (POD) activities in the 6th day of storage compared to 3rd and 0th days. Peroxidase activity decreased in control treatment on 3rd and 6th days, respectively. While the activity of this enzyme was increased in melatonin treatment. The catalase (CAT) activity content of the tissues (leaves and petals) increased on 3rd day of storage and decreased on the 6th day. Therefore, it seems melatonin may help reduce oxidative stress and the lipids peroxidation and delays process of senescence in Tuberose flower.

Salinity stress is recognized as one of the most important factors limiting plant growth. Auxin and gibberellin are one of the most important plant hormones, with the smallest variation in their levels causing extensive responses throughout the plant. It has been shown that these two hormones are introduced to environmental stresses in tandem with other hormones in order to adapt the plant to new conditions. The aim of this study was to evaluate the changes in auxin and gibberellin hormones and its relationship with changes in the physiology, anatomy and morphology of okra plant under the influence of salt stress. In this study, okra plants were exposed to salinity treatments (0, 50, 100 and 150 mM NaCl) for 7 days. After treatment, root and stem length, fresh and dry weight, auxin and gibberellin levels were measured. The results showed that the levels of auxin and gibberellin hormone decreased significantly under salinity stress. In addition, the activity of the enzyme auxin oxidase increased. In this study, the Na+/K+ ratios and electrical conductivity increased while potassium and relative water content decreased. Structural studies showed that the thickness of different organs (root, stem and leaf) and the stomatal index decreased. The study showed that the length of the spongy and palisade mesophilic cells decreased under salinity stress, and the reduction in leaf thickness is more related to the reduction in palisade mesophilic. This research enhanced our understanding about the commercial use of hormones in oredr to reduce environmental stresses.