بررسی تاثیر نانوذره اکسید آهن مغناطیسی سنتز شده و سالیسیلیک اسید بر تغییر ویژگی‌های ریخت شناسی و فیزیولوژیکی گیاهچه‌های استبرق (calotropis procera)

استبرق (calotropis procera (aiton) w.t. aiton) درختچه ای چندساله با سطوح بالایی از ترپنوئیدها می باشد که به عنوان یک گیاه دارویی موثر در پزشکی و صنعت شناخته شده است. پژوهش حاضر با هدف بهبود رشد، ویژگی های فیزیولوژیکی و مواد موثره استبرق تحت تیمار نانوذرات مغناطیسی اکسید آهن سنتز شده و سالیسیلیک اسید انجام شد. برای این منظور، گیاهچه های 21 روزه رشدیافته در شرایط هیدروپونیک با پنج سطح نانوذرات مغناطیسی (0، 50، 100، 150 و 200 میلی گرم بر لیتر) و سه غلظت سالیسیلیک اسید (0، 0.05 و 0.1 میلی مولار) تیمار شدند. دو هفته پس از تیماردهی، نتایج نشان داد نانوذرات مغناطیسی سنتز شده همراه با سالیسیلیک اسید توانایی بیشتری نسبت به سایر تیمارها در بهبود رشد، پارامترهای فیزیولوژیکی و تولید اسانس ها در گیاهچه های استبرق داشتند. غلظت 200 میلی گرم بر لیتر نانوذرات همراه با 0.1 میلی مولار سالیسیلیک اسید بیشترین تاثیر را در افزایش رشد، میزان عناصر، میزان کلروفیل a و کل، کاروتنوئیدها، قندهای محلول، پروتئین، فعالیت آنزیم آسکوربات پراکسیداز و کاتالاز داشت. همچنین در این سطح از تیمار، میزان نشت یونی، h2o2 و محتوای مالون دی آلدئید نسبت به شاهد کاهش معنی داری نشان داد. در بررسی محتویات اسانس با دستگاه گاز کروماتوگراف جرم سنجی (gc/ms) نیز مشخص شد که سیترونلال، α-ترپینئول، آلفا-پینن، کافور، لینالول، ژرانیال، α-فلاندرن، 1،8-سینئول و بتااوسیمن اجزای اصلی اسانس ها را تشکیل می دهند و تیمارهای اعمال شده سبب تغییرات قابل توجهی در میزان اسانس ها شدتد. این نتایج نشان می دهد که غلظت 200 میلی گرم بر لیتر نانوذرات همراه با 0.1 میلی مولار سالیسیلیک اسید محرک قدرتمندی برای بهبود رشد و عملکرد گیاه است.

study of the effects of synthesized iron nanoparticle and salicylic acid on change of morphological and physiological characteristics of calotropis procera seedlings

calotropis procera is a perennial shrub with high levels of terpenoids that is known as a medicinal plant with antimicrobial, anti-inflammatory, anti-cancer, and antioxidant activity. the present study aimed to improve the growth, physiological parameters, and essential oils of c. procera under synthesized magnetic nanoparticles (mnps) and salicylic acid (sa) treatments. for this purpose, 21-day-old seedlings grown under hydroponic conditions were treated with five levels of mnps (0, 50, 100, 150, and 200 mg l-1) and three sa concentrations (0.0, 0.05, 0.1 mm).  two weeks after treatment, the results showed that mnps combined with sa have more ability than all other treatments to improve growth, physiological parameters, and essential oil in c. procera seedlings. 200 mg l-1 mnps combined with 0.1 mm sa had a more pronounced impact increasing chlorophyll a and total, carotenoids, soluble sugars, protein, and the activity of ascorbate peroxidase and catalase. at this concentration, electrolyte leakage, h2o2, and malondialdehyde content showed a significant reduction as compared to the control. in an evaluation of the contents of essential oils using gc–ms, it was also found that citronellal, α-terpineol, alpha-pinene, camphor, linalool, geranial, α-phellandrene, 1,8-cineol, and β-ocymene were the main components of the essential oils, and the applied treatments resulted in significant changes in the amount of them. these results suggest that 200 mg l-1 mnps combined with the highest concentration of sa is a powerful elicitor for improving plant growth and yield.introductioncalotropis procera, widely known as stabragh, is a multipurpose plant belonging to the apocynaceae family that is used for medicine, fodder, fiber, phytoremediation, and fuel purposes. stabragh is a great source of terpenoids, flavonoids, and alkaloids, which are related to its medicinal and industrial properties. despite the socio-economic importance of stabragh, no previous study has been performed regarding improving bioactive compound production and antioxidant activities of stabragh. hence, this study aimed to set up a reproducible alternative protocol for the improvement and fast production of these valuable compounds in high quantities. recently, the successful use of abiotic factors as elicitors has been reported for the increase of secondary metabolites in plant cultures. iron oxide nanoparticles with a special surface cover of magnetic particles (mnps) are also known to play the same role. moreover, the exogenous application of salicylic acid (sa) is another practicable approach to promote secondary metabolism due to its signaling role in regulating the expression of critical genes of the stress defense pathway and maintaining ros at an optimal level. thus, in this study, sa was used as an abiotic elicitor along with mnps to boost the physiological and biochemical characteristics of stabragh, as well as minimize possible adverse effects of mnps. material and methodseeds of stabragh were collected from wild-growing plant populations in shahdad (kerman province, iran). here, hydroponic culture was considered for seedlings growth as a feasible alternative to traditional soil cultivation not only for having a large scale of uniform seedlings with high percentage of bioactive substances but also for faster growth. furthermore, to avoid any possible toxicity of synthetic nps, synthesized mnps using leaf extract of stabragh with an average size of about 11 nm were used (adabavazeh et al. 2022). the experiment was a 3*5 factorial in a completely random design involving three levels of sa treatment and five levels of mnps with three replications per treatment, each repetition consisting of one explant. for this purpose, the sterilized seeds germinated on moist filter paper in petri dishes at 25°c. after 10 days, uniform seedlings were transferred to the hydroponic system with ½ hoagland solution and were grown in the growth chamber. after the emergence of 4 to 6 leaves of the plant, different concentrations (0, 50, 100, 150, and 200 mg l-1) of mnps were sprayed on the leaves (seven times for two weeks to avoid leaf damage). different concentrations of sa (0, 0.05, and 0.1 mm) were added to the hoagland solution. after two weeks, the morphological, physiological parameters, and the main essential oils were measured. result and discussionthis study confirmed that the additions of mnps at 200 mg l-1 could increase the growth parameters, chlorophyll, soluble sugar, and protein contents as well as absorption of essential nutrients, except for the root length. the enhanced seedlings’ growth with mnps could be related to increase in chlorophyll, soluble sugar, and protein contents. it is speculated that mnps may have potentially increased these parameters by supplying sufficient fe2+. iron is an intermediary for the electron transmission chain, biosynthesis of cytochromes, synthesizing nadp+ in photosynthesis, contributing to the synthesis of 5-aminolevulinic acid - the precursor of chlorophyll, which has a positive influence on plant growth and productivity. moreover, iron as an enzyme cofactor, which plays an important role in electron transfer and catalysis can affect the metabolism of sugars and nitrogen and increase the production of sugars and protein. however, mnps were substantially more effective when applied with sa. also, a reduction in electrolyte leakage, h2o2, and mda contents was achieved under 200 mg l-1 mnps with 0.1 sa treatments. it is assumed that mnps may have potentially lowered the oxidative damage either by intrinsic enzyme peroxidase-like activity or activation of the cellular enzymes, especially apx via the h2o2 signaling pathway. sa may also increase antioxidant activity and polyamines, which help to inhibit membrane injury by retarding lipid peroxidation and preserving membrane integrity. another important finding of this research was greater production of geranial, 1, 8-cineol, a-phellandrene, citronellal, camphor, and terpinen-4-ol contents as the main essential oils in stabragh under 200 mg l-1 mnps with 0.1 sa. the rise in essential oil contents may be attributed to an increase in soluble sugar contents and the activation of genes related to the biosynthetic pathway of the specific secondary metabolite. conclusionthe results of this study confirm that the synthesized mnps can serve as a favorable excipient for the improvement of both growth and valuable secondary metabolites, especially when combined with sa.