جستجوی مقالات مرتبط با کلیدواژه "salicylic acid" در نشریات گروه "باغبانی"

To observe the effect of plant growth-promoting rhizobacteria (PGPR) and salicylic acid under drought stress conditions on yarrow, an experiment was arranged as split-plot factorial based on a randomized complete block design with three replications in a research farm in Basht, Kohgiluyeh and Boyer-ahmad provice, during two years (2018 and 2019). Drought stress as the main factor in two levels (drought and non-drought stress), and secondary factors include foliar spraying with salicylic acid in two levels: control (no foliar spraying) and foliar spraying with salicylic acid (400 mg/L), and PGPR at four levels: control (no inoculation with bacteria), inoculation with Pseudomonas, inoculation with Azotobacterial and inoculation with both bacteria were assigned to the main and sub-plots, respectively. The results of a two-year combined variance analysis showed that effects of year, drought stress, bacteria, salicylic acid and drought stress × salicylic acid × bacteria on plant height, thousand seed weight, flower yield, biological yield, essential oil content, and essential oil yield were significant. The average flower yield in the first year was 731.45 kg/ha, which had a significant difference compared to the second year. The highest plant height (65.94 cm) was obtained from azotobacterial and salicylic acid treatment under non-drought stress conditions. Meanwhile, in both conditions (non-drought stress and drought stress), the maximum thousand seed weight (0.29 and 0.23 g), flower yield (1389 and 492 kg/ha), biological yield (8634 and 4106 kg/ha), harvest index (16.09 and 11.99 %), essential oil content (1.41 and 0.80 %) and essential oil yield (1.77 and 19.54 kg/ha) were obtained for bacteria and salicylic acid treatment. Although drought stress caused a significant decrease in all traits, especially flower yield, essential oil content and yield, the use of growth-promoting bacteria or salicylic acid, especially in the treatment of simultaneous application of two bacteria and salicylic acid, significantly reduced the damage of drought stress on flower yield, essential oil content and yield compared to the control.

Plants are exposed to various environmental stresses during their growth period in nature and under field conditions. Due to its medicinal and therapeutic properties, Silybum marianum L. Gaertn. has been used since ancient times for the treatment of liver and gallbladder diseases. This study aimed to investigate the response of Silybum marianum to plant growth regulators under different soil moisture conditions.

The present study was conducted in the agricultural year 1401-1400 at the Forests and Rangelands Research Institute research farm located in Karaj, Iran. The research farm is 5 kilometers southeast of Karaj city at a geographical latitude of 35 degrees and 48 minutes north and a longitude of 51 minutes east, with an elevation of 1320 meters above sea level. The study was carried out in a randomized complete block design with three replications. The experimental treatments included different levels of field capacity (90%, 75%, 50%, 25% FC) and foliar application with plant growth regulators such as salicylic acid (75-150 mg.l-1), spermine (70-140 mg.l-1), brassinosteroid (C28) (1-1.2 µM), and water (control). Soil moisture levels were determined daily using the weighing method and TDR (Time Domain Reflectometry) in the range between field capacity and 25% soil moisture content. Irrigation was conducted according to the desired treatments throughout the growth period based on the plotted graph and with the help of TDR. Foliar spraying was performed seven days apart in three stages, five months after seed sowing in April. At the end of the study, traits including average leaf number, leaf area, canopy diameter, number of lateral branches, root length, root collar diameter, days to leaf emergence, fruit antioxidant capacity, fruit color index, seed ash percentage, leaf sugar content, thousand seed weight, fruit yield, and oil content were measured.

 The study showed that the reduction of field capacity (FC) reduced growth and yield traits in the plant compared to the control treatment. However, the foliar application of plant growth regulators improved growth traits effectively. For instance, the leaf number in the 25% field capacity treatment was almost halved compared to the control treatment (90% field capacity). Foliar spraying with brassinosteroids prevented a significant decrease in leaf number in the plant under different field capacity levels. The highest leaf area was observed in the treatment with 140 mg.l-1spermine + 75% field capacity. Foliar spraying with spermine and brassinosteroids had a significant effect on improving growth traits under stress conditions. Foliar spraying with spermine or brassinosteroids resulted in the highest oil content in the fruit under 50% field capacity conditions. Under 75% field capacity, foliar spraying with brassinosteroids (1 µM) increased fruit yield in the plant by 71% compared to the control treatment at the same stress level and by 5.5% compared to the control treatment under 90% field capacity conditions. The correlation analysis between color indices and fruit antioxidant capacity showed a positive and significant correlation between the percentage of fruit antioxidant capacity and brightness index (L), indicating that fruits with darker colors had higher antioxidant capacity. However, the redness index (a) and yellowness index (b) had a negative and significant correlation with fruit antioxidant capacity.

The research findings have shown that reducing field capacity reduces plants' vegetative and reproductive growth parameters. However, foliar spraying plants with plant growth regulators improves plant growth conditions under water-limited conditions. In general, based on the research results, foliar spraying of plants with spermine at a concentration of 140 mg.l-1 helps improve the growth and performance characteristics, increasing the plant's resistance to moisture stress conditions in the soil.

The beneficial effects of the chamomile plant have been attributed to its essential oil, so any factor that affects the quantity of its essential oil will be of interest to researchers. To investigate the effect of plant growth regulators salicylic acid and methyl jasmonate on the production of secondary metabolites in chamomile plants, this experiment was conducted under the native in vitro conditions of Sharbian City. To conduct this research, chamomile seeds were collected from Sharbian (N ʺ52 58 37 and E ʺ06 ʹ11 ˚), East Azerbaijan province. After transfer, the seeds were sterilized for 15 minutes in a detergent. Their surfaces were disinfected with 70% alcohol for 45 seconds and then with sodium hypochlorite for 30 minutes. After surface disinfection, they were washed twice with distilled water. The basic culture medium in this study was the MS culture medium. All cultures were placed in the growth chamber at a temperature of 24±2°C and 16 hours of light and 8 hours of darkness. A factorial experiment was performed in a complete random design with three replications. Test treatments included salicylic acid (SA) and methyl jasmonate (MeJA) at five levels (0, 50, 100, 200, 400 μM). Minguez-Mosquera and Perez-Galvez methods were applied to determine photosynthetic pigment amounts. The amount of phenolic compounds in the plant extract was measured with a slight modification based on the Slinkard and Singleton method with the Folin-Ciocalteau reagent. The data related to this research were analyzed using SAS V.9.g.1 statistical software. The comparison of treatment averages was done with Duncan's test at 5% and 1%. Graphs were drawn using Microsoft Excel software. The analysis of variance showed that the interaction effect of the applied treatments on the traits of stem weight, root weight, stem length, and root length is significant at the 1% probability level. In addition, it is significant on the number of stems at the 5% probability level. The comparison of the averages showed that the highest amount of stem weight was obtained in the interaction effect of (50 µM) SA and (200 µM) MeJA, and the lowest amount of stem weight was obtained in the interaction effect of (400 µM) SA and (400 µM) MeJA treatment. The comparison of the means shows a significant difference in this trait. The highest amount of root weight was obtained in the interaction effect of (100 µM) SA and (100 µM) MeJA, and the lowest amount of root weight was obtained in the interaction of (400 µM) SA and (400 µM) MeJA treatment. Came. A comparison of the averages showed that the highest number of stems was obtained in the interaction of (100 µM) SA and (50 µM) MeJA, and the lowest number of stems was obtained in the interaction of (400 µM) SA and (200 µM) MeJA. The comparison of the means showed the significance of the stem and root length traits. The highest value of these two traits was due to the interaction of (50 µM) SA and (100 µM) MeJA treatments, and the lowest value of stem length was in the combination of (400 µM) SA and (µM) treatments. 400) MeJA and root length were measured from the combination of SA (400 µM) and MeJA (200 µM) treatments. In the biochemical traits, variance analysis of the data showed that the effect of SA levels on the amount of chlorophyll a, b, carotenoid, total chlorophyll, phenol, and flavonoid in all three wavelengths was significant at the 1% probability level. In this experiment, it was shown that metabolite production depends not only on enzyme activity but also on stimulant concentration. Increasing the stimulus more than usual not only increases metabolism but also reduces or stops the production of metabolites through the reduction of enzyme activity (probably through the reduction of the corresponding gene expression).

Various methods of stress directly affected the growth and production yield of numerous plants. For example, environmental stress reduces the tomato manufacturing by the disrupting its natural metabolism, or, salinity stresses affect the it is growth and development from the germination stage to the fruit ripening stage. Salinity in tomatoes by stimulating the biosynthesis of growth regulators such as ethylene and abscisic acid leads to the acceleration of the aging of the leaves. Therefore, development of different methods to induce salinity stress tolerance in plants is necessary. Some approaches were studied to develop the salinity tolerant plants such as genetic breeding, environmental improvements and usage of phytohormones and signal molecules. Salicylic acid or orthohydroxybenzoic acid plays an important role in regulating the physiological and biochemical responses of plants to stress conditions, which improves the plant's resistance to adverse environmental conditions. For instance, salicylic acid is a facile and effective way to increase plant productivity under salt stress conditions. Considering the positive effects of salicylic acid in modulating the effects of salinity, this study was conducted with the aim of investigating the effects of salicylic acid’s usage in modulating the harmful effects of salinity on some vegetative, physiological, quantitative and qualitative characteristics of two tomato cultivars of Baneh local mass and Semi Dwarf line.

To investigate the effect of salicylic acid in modulating the effects of salinity stress in tomato, a factorial experiment was conducted in the form of a randomized complete block design, with 12 treatments, in 3 replications and with a total of 36 experimental units in the hydroponic greenhouse of the Department of Horticulture, Faculty of Agriculture, and university of Tabriz. The treatments included two levels of salicylic acid (0 and 1 mM) and salinity levels (0, 35 and 70 mM NaCl) on two tomato cultivars of Baneh and Semi Dwarf.

The results showed that in Baneh and Semi Dwarf cultivars, the increase in salinity levels caused a decrease in vegetative indices, meanwhile the treatment of salicylic acid along with salt stress increased same indices. Also, salt stress caused yield reduction in both Baneh and Semi Dwarf cultivars. By examining the qualitative indicators, it was observed that titratable acidity and vitamin C increased with salt stress and salicylic acid treatment in both cultivars. In terms of physiological indicators, the amount of proline increased at different salinity levels with salicylic acid treatment, but the amount of leaf chlorophyll index decreased with the increase of same condition.

The results of testing the effect of salicylic acid and the effects of salinity stress on vegetative, quantitative, qualitative and physiological indicators in Baneh and Semi Dwarf tomatoes showed a remarkable difference in terms of significance. In terms of vegetative traits; Plant height, leaf area index, shoot wet in Baneh and Semi Dwarf cultivars decreased with increasing salinity levels of vegetative indices, but salicylic acid treatment along with salinity stress increased same indices. Indicators such as yield, fresh weight of fruit, and percentage of dry matter of fruit showed different responses to different levels of salinity and salicylic acid treatment. The fresh weight of fruit increased with the application of salicylic acid. Also, salt stress caused an increase in the percentage of dry matter of the fruit. But salt stress caused yield reduction in both Baneh and Semi Dwarf cultivars. In terms of quality indicators; the amount of titratable acidity and vitamin C increased with salt stress and salicylic acid treatment in both cultivars. In terms of physiological indicators, the level of proline increased across various salinity levels with salicylic acid treatment. However, the leaf chlorophyll index decreased with rising salinity levels, even in the presence of salicylic acid treatment. Overall, salinity stress caused a decrease in most analyzed traits in the Baneh and Semi Dwarf cultivars. Nevertheless, it led to improvements in certain quality traits. Additionally, salicylic acid treatment enhanced the mentioned indices in most of the examined traits in both cultivars. Therefore, considering the positive effects of salicylic acid treatment on Baneh and Semi Dwarf cultivars under salinity stress conditions, its use is recommended.

Hibiscus sabdariffa L., commonly known as Roselle, is a plant cultivated in many regions of the world regions. Roselle has been used as a medicinal herb in traditional medicine for controlling and treating different diseases and physical ailments. These therapeutic effects are attributed to active compounds such as carotenoids, fatty acids, and phenolic compounds, including phenolic acids and flavonoids. One common method to stimulate plants for increased production of active compounds is subjecting them to various types of stresses, such as drought or salinity, along with plant growth regulators. This study investigated salicylic acid's effect on the phytochemical content and various biological properties of Roselle plants under water scarcity conditions.

The experiment was conducted as a factorial experiment in a completely randomized design, including irrigation intervals at three levels: three days (D1), five days (D2), and seven days (D3), and foliar application of salicylic acid at three levels: 0 (SA0), 0.75 mM (SA1), and 1.25 mM (SA2), with three replicates in a research greenhouse at the International Imam Khomeini University. The required seeds for cultivation were obtained from Pakanbazr Company in Isfahan. The imposition of drought stress through irrigation intervals of 3, 5, and 7 days started at the 4-leaf stage of the plants, and the plant spraying with salicylic acid was performed at the 6-leaf stage, three days before the start of irrigation treatments. The measurement of electrolyte leakage and malondialdehyde content was carried out to determine membrane stability and lipid peroxidation level. Additionally, the measurement of proline content and the activity of three antioxidant enzymes, including peroxidase, catalase, and ascorbate peroxidase, was performed in different samples. Furthermore, the total phenolic, flavonoid, and anthocyanin contents, as the main secondary metabolites of Roselle plants, were measured. The biological and medicinal properties, including the free radical scavenging activity (DPPH) and α-glucosidase inhibitory activity, were also evaluated. The obtained data were analyzed using SAS statistical software version 9.4. Mean comparisons were conducted using Duncan's multiple range test at a significance level of 5%.

The results showed both electrolyte leakage and malondialdehyde content increased significantly with increasing levels of applied drought stress on Roselle plants. However, overall, applying salicylic acid treatments led to a decrease in both indicators. The measurement of proline content in Roselle samples showed that the highest amount of proline was observed in plants subjected to the highest drought stress and treated with the 1.5 mM salicylic acid solution. The activity of all three antioxidant enzymes increased with the intensity of the applied drought stress and the concentration of salicylic acid solutions. Roselle's highest levels of phenolic and anthocyanin content were observed in samples sprayed with 1.5 mM salicylic acid solution. The change in anthocyanin content of Roselle plants also demonstrated that increasing the severity of water scarcity resulted in higher levels of this compound. The highest DPPH free radical scavenging activity was observed in Roselle samples grown under the highest drought severity and sprayed with the highest concentration of salicylic acid (61.93%). The highest antioxidant activity was also observed in samples treated with the highest concentration of salicylic acid solution in all irrigation regimes. The highest α-glucosidase inhibitory activity (69.2% and 67.7%) was associated with Roselle samples grown under the highest applied drought severity, sprayed with 1.5 mM and 0.75 mM salicylic acid solutions, respectively.

It can be concluded that the use of salicylic acid as a growth regulator can contribute to the enhancement of phytochemical content, especially secondary metabolites such as phenolic and flavonoid compounds, anthocyanins, and the elevation of defensive parameters such as the activation of antioxidant enzymes, as well as an increase in osmolyte content like proline in Roselle plants. These effects assist the plants in exhibiting greater resistance to drought stress and mitigating the negative impacts of this type of stress on the plant.

Thymbra spicata L. belongs to the Lamiaceae family and is a rich source of aromatic compounds and essential oils. This research was conducted to study the effect of salicylic acid and chitosan elicitors on the growth indicators and DXR gene expression in T. spicata L. under different levels of irrigation towards enhancing the performance of this medicinal plant in experimental pots in a greenhouse in Ilam province during 2017-18. A factorial design was used with 15 treatments and three replications in a completely randomized study. Irrigation regimes at three levels of normal (A₁), 70% of field capacity (A₂), 40% of field capacity (A₃), and foliar spraying at five levels, including control (B₁), chitosan at concentrations of 0.5 g.l-1 (B₂) and 1 g.l-1 (B₃), salicylic acid foliar spraying at concentrations of 2.5 mM (B₄) and 5.0 mM (B₅) were used at the 10-12 leaf stage. To prepare chitosan and salicylic acid elicitors, the powders were dissolved in 5% acetic acid and then adjusted to desired concentrations with ddH2O. Irrigation regimes were applied three months after cultivation (15-20 cm seedlings). To apply the elicitors simultaneously with the water stress treatment, foliar spraying was done three times at ten-day intervals. Quantitative RT-PCR was used to investigate the expression changes of the DXR gene, which is one of the key genes in the carvacrol biosynthesis pathway. In this regard, total RNA was extracted, and cDNA was synthesized after assessment of its quantity and quality. With the aid of specific primers, the target sequence was amplified. Furthermore, using the GAPDH reference gene reported in Hyssop thyme, the gene expression level was investigated through the relative quantification method. The method of difference in cycle threshold (2-∆∆CT) and Relative Expression Software Tool (REST) were used to analyze the data. The analysis of the variance table showed the effect of different levels of irrigation on all quantitative growth indices, including plant height, root length, number of main branches, root fresh and dry weight, leaf fresh weight, stem fresh and dry weight, except leaf dry weight, were significant (p<0.01). The interactive effect of low irrigation and foliar spray of salicylic acid and chitosan on root fresh weight, leaf fresh weight, and stem fresh weight was significant at 1%. Accordingly, the interaction effect of irrigation and foliar spraying on the dry weight of the stem was significant at the 5% probability level. The results showed that the interactive effect of irrigation and foliar spray on leaf dry weight, number of main branches, and root length was insignificant. In this study, DXR gene expression did not show many changes after applying two different levels of chitosan (0.5 and 1.0 g.l-1). In contrast, salicylic acid treatment with 2.5 mM was significant at 1% probability and caused an increase in gene expression. The transcript level of this gene increased 29.72 times after applying 5.0 mM of this solution, which was significant at the 1% level. The amount of low irrigation decreased this gene's expression. Based on the obtained data, the normal irrigation method is the most suitable for hyssop thyme plants regarding their growth indicators. Foliar spraying of chitosan at different levels did not significantly affect growth indices and DXR gene expression. At the same time, salicylic acid increased them in this species. As a result, salicylic acid elicitor can increase carvacrol yield and biosynthesis.

To investigate the effects of drought stress, salicylic acid, and polyamines on plant growth yield and oil and seeds essential oil content in Nigella sativa L., a factorial experiment was conducted in a completely randomized design with three replications in the research greenhouse of Shirvan Azad University in 2020-21 cropping year. The experimental treatments included drought stress at four levels (25, 50, 75, and 100% of field capacity) as the first factor and foliar application of salicylic acid, putrescine, and spermidine each at two levels (0.5 and 1 mM) as the second factor. The results showed that the highest number of fertile capsules per plant (12.66), number of seeds per capsule (96.24), and harvest index (58.69%) were obtained in the 100% of field capacity treatment. Also, the highest seed yield per pot was obtained in the 100% of field capacity treatment (16.05 g) and 1 mM salicylic acid (11.46 g). On the other hand, the highest plant height (62.5 cm), dry weight of single plant (6.44 g), biomass in pot (32.2 g), oil content (31.21%), and oil yield (5.71 g.pot-1) were obtained in the treatment of 100% of field capacity + 1 mM salicylic acid and also, the highest essential oil content (0.09%) was obtained in the treatment of 25% of field capacity + 1 mM salicylic acid. Overall, the results showed that full irrigation (100% of field capacity) + 1 mM salicylic acid foliar application was the best treatment for N. sativa under greenhouse conditions. In general, the plant growth characteristics decreased with increasing stress severity, but the negative effects of drought stress were moderated with increasing the salicylic acid foliar application.

Trigonelline is one of the valuable secondary metabolites of fenugreek plant. Plant cell suspension culture is a recommended method for in vitro production of secondary metabolites. To study the possibility of Trigonelline production in fenugreek cell suspension culture, factorial experiment based on CRD was designed.  In this research different explants such as leaf, stem and root were used on MS medium including four different concentration of 2,4-D and BAP plant growth regulators to study callus induction ability in fenugreek plant. The results showed that largest size of calluses belonged to the root explant under 2,4-D(2mg/l) with 315 mm and stem explant on MS including 1 mg/l  BAP with  320 mm.  Also, the highest fresh and dry weight of callus belonged to root explant in MS including 2 mg / l 2,4-D  with 1. 5 and 0.08g and stem explant in concentration of 1 mg / l BAP with 1.5 g and 0.07g. The data registered for callus dry weight showed the same results. Three different elicitors methyl jasmonate, salicylic acid and yeast extract were used to increase the in vitro production of Trigonelline using cell suspension culture obtained from Fenugreek calluses. The highest amounts of Trigonelline was obtained from 100 μM salicylic acid.

In order to study the effects of water deficit stress and salicylic acid application on morphological and physiological characteristic of Ziziphora clinopodioides Lam. a factorial experiment based on a complete randomized block design with four water deficit stress levels (100%, 75%, 50% and 30% FC) and three levels of salicylic acid (0, 0.5 and 1 mM) in three replications was performed in greenhouse condition. Water deficit stress decreased plant, leaf and stem dry weight, leaf area, chlorophyll a, b and total chlorophyll content, carotenoids content and essential oil yield, while these traits increased by application of SA. Total phenol content was increased by water deficit stress and SA application. The highest level of plant (18.2g), leaf (6.6g), and stem (8g) dry weight were observed in 100% FC with 0.5 mM SA. Essential oil yield was decreased by water deficit stress and the highest level of this character was obtained in 100% FC with 0.5 mM SA application. According to the obtained results, Z. clinopodioides needs to irrigate at field capacity along with  0.5 mM SA in order to reach to the highest growth and chemical yields.

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.

Grape (V. vinifera L.) is one of the most important crops in the world and Iran, and play a major role in the export income. According to World Food Organization statistics, the area under global cultivation has been seven million hectares and Iran ranks seventh in the world with 316,000 hectares. Grape production is about 77.5 million tons and Iran is ninth in the world with production of about 2.5 million tons. Fars province is in the first place with 75,000 hectares of fertile vineyards. Qazvin, Khorasan Razavi, West Azarbaijan, Hamadan and East Azarbaijan provinces are also ranked next. Cold stress is one of the constraints on the cultivation of grapes, so prevention of frost damage is one of the important points in the world's grape areas. This damage could be due to early autumn cold and late spring in the temperate region, such as winter frost of 2007, early autumn frost of 2015 and late spring frost of 2014 and 2017. Protecting plants against the harmful effects of low temperatures in agriculture is considerable. One way to prevent frost damages is using plant growth regulators such as salicylic acid. It seems that salicylic acid plays a role in the resistance to the cold stress, and it probably contributes to the activity of antioxidant enzymes and hydrogen peroxide metabolism, so it reduces cold stress damages and increases the plant tolerance to frost. The role of salicylic acid against cold stress have been reported in various plants such as lemon, pistachio, peach, pomegranate, apricot and walnut. Studies have shown that application of salicylic acid on grape seedlings increased the resistance to thermal stresses by reducing ion leakage and decreased the peroxidation of the cell membranes. Also, SA increased the proline and soluble carbohydrates in Plukenetia volubilis seedlings. In the present study, the effects of salicylic acid was investigated on the reaction of potted seedlings of some grape varieties under the spring frost. Then shoot burn percentage, recovery, ion leakage and peroxidation of membrane lipids of seedlings were investigated after cold application. Therefore, the changes in the amount of some osmotic regulators such as proline, soluble carbohydrates, and antioxidants such as phenolic compounds were evaluated by salicylic acid and cold treatments.

This research was carried out in greenhouse of Department of Horticulture Engineering of College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran, in spring 2017 on two-year potted seedlings. It was carried out in a completely randomized design with three replications to evaluate the effects of salicylic acid on reducing the damage of spring frost in some grape varieties such as Bidaneh Sefid, Perlette and Riparia species. Salicylic acid was sprayed at 0, 0.5 and 1 mM in E-L=11 on two year-old potted. After 24 hours, cold treatment was applied at 0 and -2 °C and normal temperature (as control) for 8 h. Control was in the greenhouse with natural temperature. Potted plants were transferred to the greenhouse and after 72 hours, the burn percentage was calculated. Also, recovery of the seedling was determined 20 days after the cold. Other parameters were measured such as ion leakage, malondialdehyde, soluble carbohydrates, proline and phenolic compounds. Statistical analysis and mean comparison of the results was done by SPSS and LSD test.

According to the results, salicylic acid and cold treatments had significant effects on some characteristics of Vinifera species such as Bidaneh Sefid, Perlette and Riparia species. The results showed that with increasing the cold stress to -2 °C, the burned shoot percentage was increased and the grown buds percentage was decreased compared to control, and electrolytic leakage and malondialdehyde were increased at same temperature. Salicylic acid 1 mM reduced the damage to shoots and increased the recovery of seedlings. The lowest amount of electrolytic leakage and malondialdehyde were observed in 1 mM salicylic acid treated seedlings compared to non-treated. According to the results, application 1mM salicylic acid increased osmotic regulators and antioxidants such as proline, solution carbohydrates and phenolic compounds. There was a significant difference between Vinifera and Riparya species at -2 °C in some parameters such as burned shoot, recovery, ion leakage and malondialdehyde. Also, there were significant differences between Bidaneh Sefid, Perlette and Riparia species at -2 °C and 1 mM in proline, solution carbohydrates and phenolic compounds. It has been reported that salicylic acid plays a role of osmotic regulation for the cell and it can reduce the damage of frost by stimulating the hydrolysis of insoluble carbohydrates or proteins and enhancing compounds such as soluble carbohydrates, so it led to reduce the freezing point of the tissue. Increasing in soluble carbohydrates have been reported in grapes and lemon by salicylic acid spraying.

Spring frost has damaging effects on grapevine and can lead to a lot of economic damage to gardeners. Therefore, it can be prevented by some plant regulators such as salicylic acid. The results of the present study showed that the damage caused by cold treatment in control seedlings was more than the plants that were treated with salicylic acid and concentration of 1 mM salicylic acid at 2°C had a positive effect on reduction of morphological damage severity as well as reduction peroxidation of the cell membrane. Cold tolerance of seedlings may be due to the role of salicylic acid in increasing antioxidant substances such as phenolic compounds, as well as in increasing osmotic regulators such as proline and soluble carbohydrates, thereby increasing cell sap concentration and tissue freezing point. This reduced the negative effects of low temperature and reduced cell membrane damage and electrolyte leakage and improved the recovery ability of two-year-old potted seedlings of Bidaneh Sefid, Perlette and Riparia species. So, it can be concluded that among different tested species, Riparia had the lowest percentage of shoot burn and highest recovery ability than the cultivars of Vinifera. Among the genotypes of Vinifera species, Bidaneh Sefid was the most proline and soluble carbohydrate compared to Perlette, indicating a higher adaptation to cold conditions.

This research was aimed to investigate the foliar application of Plant Growth Regulators (PGRs) on growth parameters, yield, some morphophysiological traits, and alkaloids of rosea periwinkle (Catharanthus roseus L. (G. Don) under drought stress conditions. The field study was conducted based on split-plot factorial in the randomized complete block design (RCBD) with three replications at the research farms of Shahid Chamran University in Ahwaz city in 2016-17. The experimental treatments included drought stress as the main factor at three levels of 40% (control), 60% and 80% of maximum allowable depletion (MAD) and foliar application of jasmonic acid (JA) at two levels (0 and 10 µM) and salicylic acid (SA) at three levels (0, 0.1, 1, and 10 mM) as subplots. Based on the results of the mean comparison of main effects, drought stress (80% MAD) reduced 36.6% of fresh weight and 25.4% of the dry weight of the plant compared to the control. The treatment 10 mM SA resulted in 13.4, 125.5, and 59.6% increases in plant height, leaf area and flower dry weight, respectively, compared to the control. The foliar application of JA increased flower dry weight and plant fresh weight by 16.3 and 8.6%, respectively. The results showed that the foliar application of SA in concentrations of 1 and 10 mM caused the highest content of vincristine and vinblastine, respectively. The interaction of both PGRs and drought stress showed the highest alkaloids content. The highest vinblastine and vincristine under severe drought stress were obtained in foliar application of 1 mM SA+10µM JA and 10 mM SA+10µM JA, respectively.

Water deficit has been the major contributor to the decline in plant yield. Soil amendment and certain hormonal agents are some strategies applied to mitigate the adverse effects of drought stress. The purpose of this study was to investigate the effects of one soil modifier and one growth regulator on some physiological and morphological characteristics of Borago officinalis L. under water deficit conditions. The experiment was implemented as a split-factorial in a randomized complete block design with four replications at the research farm of Agriculture Faculty of Shahroud University of Technology, Iran during 2017- 2018. The main plots consisted of three levels of irrigation (usual irrigation every five days, irrigation every 10 and 15 days) and sub-plots consisted of biochar at three levels (0, 5 and 10 t ha-1) and salicylic acid at two levels (0 and 0.5 mM). Based on the results, biochar, salicylic acid, and water deficit factors affected the number of flowering stems, number of stems, stem height, the amount of chlorophylls a and b, total chlorophyll, and carotenoids significantly. Interactions between salicylic acid and water deficit levels had the most effects on carotenoids and chlorophyll b. Triple interaction of factors also affected the total dry weight, number of flowering stems, the number of stems, stem height, and chlorophyll b. Generally, water deficit stress decreased the amount of photosynthetic pigments and leaf growth indices of European borage compared to control, and salicylic acid and biochar reduced the negative effects on the amount of photosynthetic pigments. Therefore, the use of biochar as a soil modifier and salicylic acid as a growth regulator seems to be useful in ameliorating some of the negative effects of water stress on Borago officinalis.

The present study was conducted to evaluate the effects of salicylic acid on freezing tolerance in Grapevine (Vitis vinifera cv. Shahani) as a factorial based on randomized complete block design with three replications in 94 and 95 years. Factors in the first year included SA (0, 0.5 and 1 mM) foliar application at the time of the veraision, harvest, one month after harvest and three times. Freezing treatments were 4 (control), -15, 18- and 21- °C on cuttings that collected in January and March. Second year experiment based on the results of the first year and spraying with concentrations of 0, 0.5 and 1.5 mM in the stage of one month after harvest and freezing at 4, -17, -19 and -21 °C on the cutting that collected in January and March. Based on the results of this study, the use of the SA 0.5 and 1 mM in the first year and 0.5 and 1.5 mM in the second experiment reduced the peroxidation of membrane lipids and thus reduced the level of ionic and phenolic leakage and malondialdehyde after freezing stress and increased carbohydrate solution, proline and phenolic compounds at both sampling times in January and March. So it seems that SA could decrease effects of low temperatures and damage to cell lipids. Also, the results showed which deduction the temperature to -21°C reduced the vegetative parameters of cuttings and it seems that SA could improve the cold stress damages in cuttings by increasing some of the biochemical parameters.

Salicylic acid is an important signal molecule modulating plant responses to abiotic (drought) stresses. A pot factorial experiment based on completely randomized design with three replications was carried out to investigate the effect of salicylic acid on yield and essential oil content of fenugreek under water deficit conditions. Factors were two irrigation levels (50 and 100% of field capacity) and four salicylic acid doses (0, 0.5, 1 and 1.5 mM). Results showed that interaction effect of water stress levels and salicylic acid doses was significant (P≤0.01) for number of pods per plant, 1000-seed weight, protein percent, proline and total soluble sugars. Maximum grain yield (119.2 g/m2) was obtained with application of 1.5 mM salicylic acid and water deficit stress showed significant difference with respect to optimum irrigation. Maximum protein percent (13.83%) was obtained under water deficit conditions and without application of salicylic acid. There was no difference in essential oil percent in 1 mM foliar application of salicylic acid between optimum irrigation (1.4%) and water deficit conditions (1.44%). Therefore, with respect to different responses of studied traits to different levels of salicylic acid, it could be concluded that salicylic acid is able to reduce and adjust the negative effects of water deficit stress on fenugreek plant.

In order to study the effect of water deficit and foliar application of salicylic acid and spermine on the phenological stages and caffeic acid derivatives yield of Echinacea purpurea L., a three replicated split- plot experiment was conducted based on a randomized complete block design during 2016 and 2017 growing seasons at the research field of Research Institute of Forests and Rangelands, Iran. In this experiment, three irrigation regimes (irrigation after 20, 40 and 60% depletion of soil available water) were accommodated in main plots and salicylic acid (SA) and spermine (SPM) spray treatments (Control (no spray), spray at five levels of 75 mg/l SA, 150 mg/l SA, 75 mg/l SPM, 75 mg/l SA+75 mg/l SPM and 150 mg/l SA+75 mg/l SPM) were considered in subplots. The exogenous SA and SPM were applied on the foliage at two steps, 10-days apart and at the beginning of stem elongation stage. The effects of irrigation regime and spray treatments were significant on the traits studied. Drought stress decreased the number of days to phenological stages, the yield of echinacoside and cynarin in flower and cichoric acid, and caftaric acid and cynarin in leaves, but increased the yield of chlorogenic acid in flowers and caffeic acid derivatives (cichoric acid, echinacoside, chlorogenic acid, caftaric acid and cynarin) in roots. The foliar application of salicylic acid and spermine increased all studied traits. The interaction between water deficit and foliar spray was significant on the yield of caffeic acid derivatives in roots. The highest yield of cichoric acid (9.49 kg/ha), echinacoside (0.67 kg/ha), chlorogenic acid (0.26 kg/ha), caftaric acid (7.31 kg/ha) and cynarin (0.27 kg/ha) in roots was obtained at irrigation after 60% depletion of soil available water and simultaneous application of high concentrations of SA and SPM. Based on the results of the present study, the foliar application of SA and SPM improved the yield of caffeic acid derivatives in coneflower under both normal and water stress conditions.

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.

The current study was conducted to investigate the effect of 24-hour short treatment of benzyl adenine (zero and 0.1 mM) and salicylic acid (zero, 0.001, 0.01, 0.1 and 1.0 mM) on the vase life of Lily cv. Fangio. The measured traits were leaf fresh weight (on zero, first, third, and seventh days), the contents of anthocyanin, flavonoids, carotenoids, chlorophylls a, b and total (on zero and seventh day) and vase life. Results showed that maximum vase life was obtained in 1.0 mM salicylic acid and zero benzyl adenine. In addition, the leaf fresh weight was increased by 9.67% in 1.0 mM salicylic acid and 0.1 mM benzyl adenine from the first to the seventh day after treatment. The values of photosynthetic pigments (chlorophylls a, b and total, and carotenoids) remained constant in 0.1 mM benzyl adenine and 0.1 mM salicylic acid treatment during this period. The highest increase of anthocyanin content was observed in the 0.001 mM salicylic acid and no benzyl adenine treatment, as compared to control. The highest flavonoid content was observed in zero mM salicylic acid and 0.1 mM benzyl adenine, which was significantly increased during the first to the seventh days after treatment. In conclusion, 1.0 mM salicylic acid treatment is recommended to increase the vase life of Lily cv. Fangio