electrolyte leakage

Soil salinity often hinders the productivity of plants in natural and agricultural environments. The symbiosis of arbuscular mycorrhizal fungi (AMF) as a biological fertilizer can increase the salinity tolerance of plants. This study was conducted in order to investigate the effect of inoculation with mycorrhizal fungi on reducing the adverse effects of salinity stress in Iranian violets. Evaluation of the interaction effect of AMF symbiosis at three levels (without symbiosis, Glomus mosseae and Glomus intraradices) and salinity stress treatment at four levels (control, 50, 100 and 200 mM) on the growth and physiological responses of Iranian violets as a factorial layout based on a complete randomized design with three repetitions were performed. Inoculation plants had higher shoot and root biomass, carotenoid and colonization in the presence of different salinity levels. The highest amounts of total chlorophyll (1.70 mg/g fresh weight), antioxidant activity (66.56 mg/g fresh weight), flavonoid (244.05 mg/g fresh weight), phenol (28.46 mg/g of fresh weight), and ascorbate peroxidase activity (103.16 units) were observed in the treatment inoculated with G. mosseae fungus at 200 mM salinity concentration. The lowest amount of electrolyte leakage was obtained in the treatment with G. mosseae fungus in the condition without salt (18.04%). The results of the research showed that the inoculation of host plants with mycorrhizal fungi, especially G. mosseae species, had an effect on plant growth and physiology, and the positive effect of inoculating plants with fungi was significant in the conditions of plant salinity stress.

Copper, as a micronutrient, is essential for the synthesis of enzymes and proteins. However, excessive copper concentrations can be highly toxic and inhibit the photosynthetic and metabolic pathways in plants, ultimately leading to reduced biomass, delayed flowering and fruiting. Sodium nitroprusside (SNP) (as a nitric oxide donor compound) plays a significant role in plant growth and development, from germination to organ senescence, signal transduction, regulation of antioxidant defense systems, and reduction of heavy metal toxicity. In the present study, the combined effects of two levels of copper sulfate (600 and 1200 µM) and sodium nitroprusside (150 µM) were investigated on some physiological and morphological activities of okra (Abelmoschus esculentus L. cv. Clemsonspineless) is grown hydroponically. The experiments were conducted in a complete randomized design with three replications. Based on our results, the high copper concentration resulted in a reduction in chlorophyll content, essential nutrients, growth parameters and an increase in malondialdehyde, hydrogen peroxide, electrolyte leakage, total protein, proline, soluble sugars, peroxidase enzyme activity and copper content in both the roots and leaves of okra compared to the control plants. Conversely, SNP foliar spray led to an increase in total chlorophyll, uptake of essential elements, peroxidase enzyme activity and a decrease in copper concentration, malondialdehyde and hydrogen peroxide content, as well as ion leakage in okra plants. Therefore, it seems that the application of SNP was able to mitigate the negative effects of copper sulfate stress significantly and enhance the tolerance of okra plants to copper stress conditions.

Copper, as a micronutrient, is essential for the synthesis of enzymes and proteins. However, excessive copper concentrations can be highly toxic and inhibit the photosynthetic and metabolic pathways in plants, ultimately leading to reduced biomass, delayed flowering and fruiting. Sodium nitroprusside (SNP) (as a nitric oxide donor compound) plays a significant role in plant growth and development, from germination to organ senescence, signal transduction, regulation of antioxidant defense systems, and reduction of heavy metal toxicity. In the present study, the combined effects of two levels of copper sulfate (600 and 1200 µM) and sodium nitroprusside (150 µM) were investigated on some physiological and morphological activities of okra (Abelmoschus esculentus L. cv. Clemsonspineless) is grown hydroponically. The experiments were conducted in a complete randomized design with three replications. Based on our results, the high copper concentration resulted in a reduction in chlorophyll content, essential nutrients, growth parameters and an increase in malondialdehyde, hydrogen peroxide, electrolyte leakage, total protein, proline, soluble sugars, peroxidase enzyme activity and copper content in both the roots and leaves of okra compared to the control plants. Conversely, SNP foliar spray led to an increase in total chlorophyll, uptake of essential elements, peroxidase enzyme activity and a decrease in copper concentration, malondialdehyde and hydrogen peroxide content, as well as ion leakage in okra plants. Therefore, it seems that the application of SNP was able to mitigate the negative effects of copper sulfate stress significantly and enhance the tolerance of okra plants to copper stress conditions.

Salinity stress is considered one of the most important stresses in arid regions and affects 20% of arable land around the world and is continuously increasing due to climate change and human activities. Frequent and continuous droughts in Iran and drought stress and subsequent water and soil salinity make the production of more crops in arid and semi-arid regions face increasing restrictions and this causes a decrease in quantitative and qualitative yield of plants in these areas have been. To investigate the effect of salinity stress on some physiological traits of different wheat cultivars, a factorial experiment was conducted in a completely randomized design with three replications in greenhouse of Payame Noor University of Sabzevar. In this experiment, 15 wheat cultivars were compared at three levels of salinity (0, 5 and 10 dSm). Root and stem dry weight, leaf relative water content, electrolyte leakage, chlorophyll a, b and total, soluble sugars and amino proline content were measured in different cultivars. The results showed that salinity increased the dry weight of root and stem and decreased the chlorophyll concentration. In salt stress condition, the lowest amount of leaf relative water belonged to Gasgozien cultivar with 15.61% and the highest amount was Bam with 62.34%The Mihan and Bam cultivars had the highest levels of chlorophyll a and b. The highest content of relative water content, proline amino acid and soluble sugars was observed in Pishtaz, Bam and Mihan cultivars.

In order to evaluate the inoculation of mycorrhizal and growth-promoting bacteria (Pseudomonas genus) on the tolerance of European borage to cadmium toxicity, a factorial experiment was performed in the form of a completely randomized design with 3 replications in the research greenhouse of the Agriculture Faculty of Yasouj University in 2019. The experimental factors include the application of biological fertilizer at 4 levels (control, application of mycorrhiza, application of growth-stimulating bacteria and combined application of mycorrhiza and bacteria) and 4 levels of cadmium concentration (0, 25, 50 and 75 mg cadmium per kg soil). The investigated traits were included root colonization percentage, plant cadmium content, some physiological characteristics and shoot dry weight of European borage. The results showed that with the increase in cadmium concentration, electrolyte leakage, proline content and cadmium content of aerial organs increased. The use of mycorrhiza and bacteria was evaluated positively compared to their non-use, so that in all four levels of cadmium, the highest proline, chlorophyll and relative water content, as well as the lowest electrolyte leakage and shoot cadmium concentration, were obtained from the combined two biofertilizers. Application of biofertilizer increased the dry weight of the aerial parts of inoculated plants compared to the control. The results showed that in the presence of 25 and 50 mg/kg of cadmium, the combined application of bio-fertilizers reduced 21% and 17% of cadmium transfer from roots to shoots of borage. Therefore, it is recommended to use biological fertilizers in areas contaminated with cadmium.

The aim of this study was to investigate the effect of chitosan on ZmPIP gene expression, growth parameters and physiological characteristics of rapeseed under salinity stress which was performed in a factorial experiment based on a completely randomized design with 3 replications. For this purpose, rapeseed seedlings was treated with different concentrations of salinity (0, 50, 100, 150 mM) and chitosan (0, 5, 10 mg/L). ZmPIP gene expression was evaluated using Real Time PCR, germination percentage and speed, length, fresh and dry weight of root and shoot, relative leaf water content, electrolyte leakage and sodium and potassium contents. In salinity stress, treatment with chitosan increased the expression of ZmPIP gene so that the highest gene expression was at 50 and 100 mM salinity with 5 mg / l chitosan. In treared plants with salinity increased percentage and germination rate, fresh and dry length and weight of root and shoot, relative leaf water content and potassium content especially at concentrations of 100 and 150 mM with chitosan compared to salinity at the same concentration and electrolyte leakage and relative water content and sodium content reduced. It is likely that chitosan has increased plant tolerance under salinity stress by maintaining the relative leaf water content, increasing potassium and growth of shoot and root and reduce the negative effects of stress on rapeseed and increase plant resistance

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

In view of limitation of water resources in Iran, screening drought-tolerant watermelon genotypes and evaluate their response to drought stress conditions has been a research priority in country. In order to study the physiologic an agronomic response of indigenous accessions of Aliabad, Sistani and Torbat to water stress, a field study was carried out as a randomized complete block design with split plot arrangement of treatments under three water regimes, 100, 70 and 40% of required water, representing non-stress, mild stress and severe stress treatments, respectively, at Jiroft region in the spring and summer of 2017 growing seasons. The highest fruit weight and yield were at 100 and 70% required water whereas the lowest was achieved at 40% treatment. There were no remarkable differences among accessions under non-stress and 70% required water treatments while Sistani accession showed a better physiological and agronomic yield in response to increase water stress level to 40% required water. The increase of water stress led to an increase of proline concentration and activity of antioxidant enzymes of superoxide dismutase and catalase in all accessions, as this increase was higher in Sistani in comparison to other accessions. Based on the results obtained from this research, it could be state that Sistani accession with maintaining its physiological and agronomic yield showed a better tolerant under adverse condition in compared to other accessions. The utilization of indigenous and tolerant watermelon genotypes in breeding programs and irrigation managements might help in overcoming water shortage.

In order to investigate the effect of humic acid on the physiological characteristics, antioxidant activity and yield of Cape gooseberry (Physalis peruviana L.) under deficit irrigation conditions, a split plot experiment based on randomized complete block design with three replications was conducted in 2021. Treatments consisted of the arrangement of three levels of irrigation (starting irrigation at 100, 80 and 60% ETc (crop evapotranspiration)) and three levels of humic acid (0, 1.5 and 3 kg ha-1). The results showed that deficit irrigation significantly reduced fruit yield. The soil application of humic acid significantly increased leaf relative water content, antioxidant capacity, fruit yield, and decreased leaf electrolyte leakage under normal and deficit irrigation. The highest value of total phenol (18.1 mg gFW-1), flavonoid (0.47 mg gFW-1), antioxidant activity (90.06 %), proline (5.91 mg gFW-1) and catalase (0.81 μmol H2O2 g-1 FW min-1) and peroxidase (1.92 units g-1 FW min-1) enzymes activity were obtained with 3 kg ha-1 soil application of humic acid under deficit irrigation 60% ETc. The maximum fruit yield (4793.3 kg ha-1) was observed in plants treated with 3 kg ha-1 humic acid under 100% ETc irrigation. According to these results, the application of 3 kg ha-1 humic acid is suggested to improve the antioxidant capacity and fruit yield of Cape gooseberry under normal and deficit irrigation conditions.

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.

To evaluate the chilling tolerance of three commercial kiwifruit cultivars (Hayward, Golden and Red) this study was carried out as a factorial experiment using randomized block design with three replications from January to May, 2019. The first factor was kiwifruit cultivars that included three cultivars of Hayward, Golden and Red; the second factor was 3 levels of chilling [including: b1) 4 ºC, b2) -6 ºC and b2) -16 ºC] and the third factor was three phonological stages of kiwifruit cultivars including: dormancy of buds, swelling of buds and fruit-set stages. The evaluated traits included Na, K, Ca, Mg, electrolyte leakage and proline. The results revealed that Ca, Mg, electrolyte leakage index and proline content of fruit-set stage were the highest and in the dormant buds and the swelling bud stage, the difference were not statistically significant. According to the results, the highest amounts of Ca and proline content were obtained at -6 ° C. The results also showed that the highest proline content and the lowest electrolyte leakage were related to Golden cultivar. Since increasing the electrolyte leakage shows the sensitivity to cold stress, so it can be concluded that Golden cultivar was more resistant to cold than the other examined cultivars.

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

In order to investigate the effect of mycorrhizal fungi under salinity stress conditions on physiological and biochemical properties of Mexican marigold (Tagetes minuta L.), a pot factorial experiment was conducted based on a completely randomized design with two factors and three replications. The first factor was the application of two types of mycorrhizal fungi at three levels (non-inoculation, Rhizophagus intradices, and Funnetiformis mosseae) and the second factor was irrigation with salinity water at 4 levels (0, 40, 80, and 120 mM equal to 0, 3.5, 7, and 10.5 ds/m sodium chloride, respectively). The salinity treatment was applied in the plants at the eight-leaf stage and on three days a week. Results showed that application of salinity stress reduced the relative water content and chlorophyll of leaves. With increasing salinity concentration, the amount of electrolyte leakage, total carbohydrate, and proline increased in leafs. In contrast, the use of mycorrhizal fungi resulted in improved traits measured under salt stress conditions. The amount of proline, total carbohydrate, and electrolyte leakage decreased with the use of mycorrhizal fungi under stress conditions due to the positive effect of these fungi on balancing growth conditions in the plant under salt stress. Also, the highest amount of relative water content and chlorophyll a, b, and total chlorophyll of leaves were observed under non salinity stress treatment and application of R. intradices. According to the results of this research, it can be concluded that the application of salinity stress at 120 mM resulted in a significant reduction in the studied traits. Besides, the application of mycorrhiza fungi at this level of salinity could not improve the negative effects of salt stress. The use of R. intradices compared to the F. mosseae had a greater effect on the improvement of physiological and biochemical characteristics of Mexican marigold under salinity stress conditions at low salt concentration.

This study was investigated, the effect of foliar application of different levels of putrescine on physiological, biochemical traits, and essential oil content of Mexican marigold (Tagetes minuta L.) under drought stress.

The experiment was conducted as a factorial experiment in a completely randomized design with three replications in greenhouse conditions. The first factor was drought stress at three levels (75, 50, and 25% of field capacity) and the second factor was putrescine foliar application at four levels (0, 0.5, 1, and 2 mM). Four seedlings were planted in each pot. Stress was applied when the plants reached a height of about 25 cm. Putrescine was sprayed one week before flowering and every 7 days until the 80% flowering stage.

The results showed that 2 mM foliar application of putrescine was more effective than other concentrations and was able to greatly reduce the harmful effects of drought stress on this plant. With the increasing drought, antioxidant activity, total phenol, proline, and electrolyte leakage also increased, and in contrast, the relative content of leaf water, photosynthetic pigments, and soluble protein decreased. Drought also increased the activity of the antioxidant enzymes guaiacol peroxidase (GPX) and polyphenol oxidase (PPO) and the amount of malondialdehyde in this plant. With increasing drought stress up to 50% of field capacity and foliar application of 1 mM putrescine, the essential oil content of Mexican marigold increased, while under severe stress (25% of field capacity) is decreased. Putrescine decreased by inducing drought resistance. The activity of antioxidant enzymes and the amount of malondialdehyde.

The use of putrescine induced resistance to drought stress in Mexican marigold, and the use of a concentration of 2 mM can be effective and recommended.