تاثیر پیش‌تیمار سالیسیلیک‌اسید و نیتریک‌اکسید بر کاهش سمیت نانوذرات روی در گیاه فلومیس phlomis tuberosa

در پژوهش حاضر، اثر سالیسیلیک‌اسید و نیتروپروسایدسدیم بر میزان سمیت نانوذرات اکسیدروی (znonps) و سولفات‌روی (znso4) در فلومیس (phlomis tuberosa) بررسی شد. آزمایش حاضر در قالب طرح کاملاً تصادفی با سه تکرار به‌شکل کشت گلدانی در بستر پرلیت انجام شد. پس از 21 روز تیمار، گیاهان برداشت و شاخص‌های کلروفیل کل، کاروتنوئید، فنول کل، فلاونوئید، فعالیت آنزیم فنیل‌آلانین‌آمونیالیاز، کاتالاز، سوپراکسیددیسموتاز و آسکوربات‌پراکسیداز اندازه‌گیری شدند. نتایج تجزیه واریانس داده‌ها در آزمایشگاه نشان دادند اِعمال 1000 میلی‌گرم‌در‌لیتر نانوذرات اکسیدروی یا سولفات روی می‌تواند سمیت بیشتری ایجاد کند. اثر متقابل پیش‌تیمارهای سالیسیلیک‌اسید و نیتروپروساید سدیم بر نانوذرات اکسیدروی در گیاهچه‌های فلومیس معنادار بود و پیش‌تیمار سالیسیلیک‌اسید مقدار پرولین در تیمار نانوذرات اکسیدروی را افزایش داد. افزایش آنتی‌اکسیدان‌های فنول تحت‌تاثیر نانوذرات اکسیدروی و سولفات‌روی معنادار و با افزایش فعالیت آنزیم فنیل‌آلانین‌آمونیالیاز همراه بود. پیش‌تیمار سالیسیلیک‌اسید در گیاه فلومیس در مقایسه با ترکیب سالیسیلیک‌اسید و نیتریک‌اکسید بیشترین تاثیر را نشان داد. هدف پژوهش حاضر، بررسی روش‌های جدید افزایش آستانۀ تحمل گیاه فلومیس به سمیت نانوذرات اکسیدروی و سولفات‌روی بود.

the effect of salicylic acid and nitric oxide pretreatment on ‎reducing the toxicity of zinc nanoparticles in phlomis tuberosa

in this study, the effect of salicylic acid and sodium nitroprusside on the toxicity of zinc oxide nanoparticles (znonps) and zinc sulfate (znso4) in phlomis tuberosa was investigated. the purpose of this research was to investigate new methods of increasing the tolerance threshold of phlomis plants under the influence of zinc oxide and zinc sulfate nanoparticles toxicity. this experiment was conducted in the form of a completely randomized design with three replications in the form of pot cultivation in a perlite bed, and the plants were harvested after 21 days of treatment. the measured factors included total chlorophyll, carotenoid, total phenol, flavonoid, the activity of phenylalanine ammonia lyase, catalase, superoxide dismutase, and ascorbate peroxidase. the results of the analysis of the variance of the data in the laboratory showed that the application of 1000 mgl-1 of zinc oxide nanoparticles or zinc sulfate caused more toxicity. the interaction effect of salicylic acid and sodium nitroprusside pretreatments on zinc oxide nanoparticles in phlomis seedlings was significant and salicylic acid pretreatment increased the amount of proline in the treatment of zinc oxide nanoparticles. phenol antioxidants increased significantly under the effect of zinc oxide and zinc sulfate nanoparticles, which was associated with an increase in the activity of the phenylalanine ammonia lyase enzyme. salicylic acid pretreatment showed the greatest effect in the phlomis plant compared to the combination of salicylic acid and nitric oxide. introductionengineered zinc oxide nanoparticles (znonps), due to their unique physicochemical properties, have many applications in industrial, optical, electrical, cosmetic, biomedical, pharmaceutical, and agricultural fields (pullagurala et al., 2018; mosquera-sánchez et al., 2020). despite the application of zn nanoparticles in agriculture, some reports show that timarin nanoparticles can lead to zn accumulation and toxic effects in plants (molnár et al., 2020; zoufan et al., 2020). the toxicity mechanism of zinc oxide nanoparticles is better understood by using compounds that increase the tolerance and performance of plants during the treatment of nanoparticles. salicylic acid, as a phenolic compound, plays a role in controlling plant growth, seed germination, photosynthesis and flowering (arif et al., 2020). under heavy metal stress, treatment with salicylic acid reduces the toxic effects of these metals and increases plant tolerance through changes in the antioxidant system (zengin, 2014; kotapati et al., 2017; lu et al., 2018). when stresses cause the accumulation of excess reactive oxygen species, nitric oxide reacts with superoxide anions, thereby reducing the formation of other oxygen radicals (domingos et al., 2015). there are few studies on the effects of nitric oxide on the tolerance of nanoparticle toxicity in plants, which confirms this hypothesis (siddiqui et al., 2015). tripathi et al. (2017) showed that sodium nitroprusside reduces the accumulation of zinc, reactive oxygen species and malondialdehyde and increases the amount of chlorophyll and the efficiency of photosynthesis in wheat shoots under the stress of zinc oxide nanoparticles. in this research, in order to better understand the effects of zinc oxide nanoparticles, the physiological and molecular reactions of the plant when exposed to zinc were compared to zinc sulfate. the importance of the role of salicylic acid and nitric oxide in reducing the tension of zinc oxide nanoparticles in plants was mentioned. these results showed that salicylic acid pretreatment alone is effective for phlomis tuberosa plants under the stress of zinc oxide nanoparticles. materials and methodsthe seeds of phlomis tuberos (jerusalem sage) were collected from madagh near marand city, 65 km south of tabriz (45°38’e and 38°22’n) at an altitude of 1800 meters in east azarbaijan province (northwest of iran). the seeds were planted in cylindrical plastic pots containing perlite and then watered with 500 ml of hoagland solution. for pre-treatment, the seeds of gerbera and phlomis were soaked in solutions of sodium nitroprusside (snp, as no donor) and salicylic acid (sa) at a concentration of 0.1 mm for 12 hours). sixteen weeks after sowing, when the plants were about 10 cm (30 inches) tall, the pots were irrigated with 1000 ppm znonps or znso4 solution dissolved in tap water for 21 days (zn treatment). plants in the greenhouse with day and night temperatures of 25-30 degrees celsius and 19-21 degrees celsius respectively, day and night light periods of 16 and 8 hours respectively, relative humidity of 60-65% and daily light flux density of about 350-400 micromoles per square meter per second were tested during the maintenance period. after 21 days of zn treatment, plants were harvested for morphological and physiological analysis. after the determination of fresh weight (fw), leaves were dried for 48 h at 70 °c for the determination of dry weight (dw). for the latter physiological analysis, samples were stored immediately in liquid n2 until assay. for the determination of leaf concentration of chlorophyll and carotenoids, samples were homogenized in the methanol according to lichtenthaler and wellburn (1983). proline was calculated as described by bates et al., 1973. soluble sugar concentrations were determined according to the method of quentin et al. (2015). the resulting precipitate was used for starch analysis following the method of magne et al. (2006). the activity of phenylalanine ammonialyase was determined by measuring the absorbance of cinnamic acid with spectrophotometry at a wavelength of 290 nm based on the modified method of zucker (1965). superoxide dismutase (sod, ec 1.15.1.1) activity was estimated according to the method of giannopolitis and ries (1977). nitric oxide concentration was measured using the modified method described by wu et al. (2016). the digested plant solution was diluted in distilled water, and zinc content was estimated by inductively coupled plasma-atomic emission spectroscopy (icp-aes, integra xl2, gbc, australia). hplc analysis was performed using an agilent 1290 santa clara, ca, usa hplc high-performance liquid chromatography system with a diode array detector (dad) according to sinrod et al. (2019). experiments were done in a complete randomized block design with 3 replications. statistical analysis was carried out using sigma stat (3.5) with the tukey test (p<0.05). results and discussionthis research showed that the effect of pretreatment of seeds with salicylic acid, nitric oxide and the combination of salicylic acid and nitric oxide at a concentration of 0.1 mm on the physiological and biochemical parameters of phlomis under the influence of the application of zinc oxide nanoparticles and zinc sulfate at a concentration of 1000 mm gram per liter was studied and the following general results were obtained: zinc oxide and zinc sulfate nanoparticles at a concentration of 1000 ppm caused a significant decrease in plant growth due to the increase in zinc content, lipid peroxidation, hydrogen peroxide and oxidative stress. the amount of sinapyl alcohol, chlorogenic acid, ascorbic acid and cinnamic acid