تاثیر محلول‌پاشی سیلیکون بر برخی از صفات فیزیولوژیکی مرزه تابستانه (satureja hortensis l.) تحت تنش خشکی

پژوهش حاضر با هدف بررسی تاثیر محلول پاشی سیلیکون بر خنثی سازی اثرات منفی تنش خشکی بر برخی از مهم ترین ویژگی های گیاه مرزه تابستانه در طی سال های 1401-1400 به صورت فاکتوریل در قالب طرح پایه بلوک های کامل تصادفی با چهار تکرار در مزرعه تحقیقاتی شهرداری اردبیل انجام گرفت. فاکتورهای مورد بررسی در این پژوهش شامل الف) تنش خشکی در سه سطح (40، 60 و 80 درصد ظرفیت زراعی) و ب) محلول پاشی سیلیکون در چهار سطح ( غلظت های صفر (شاهد)، 0/5، 1 و 1/5 میلی مولار در لیتر) بودند. تنش خشکی در مرحله 4 تا 6 شاخه فرعی و براساس ظرفیت زراعی اعمال شد و بعد از اعمال شرایط تنش، نمونه برداری جهت اندازه گیری صفات انجام گرفت. نتایج پژوهش نشان داد که تنش خشکی به طور معنی داری موجب کاهش وزن تر، وزن خشک، ارتفاع، قند محلول، کلروفیل a، b و کل و کاروتنوئید شد، اما میزان پرولین آزاد سلول ها تحت شرایط تنش افزایش یافت. محلول پاشی سیلیکون، تاثیر مثبت و معنی داری بر صفات مورد بررسی داشت، به طوری که با افزایش غلظت سیلیکون اثرات منفی تنش خشکی تعدیل یافت. نتایج پژوهش حاضر نشان داد که می توان از سیلیکون به عنوان یک عنصر مفید در جهت افزایش عملکرد گیاهان زراعی و باغی، و همچنین افزایش تحمل به تنش های محیطی (از جمله تنش کم آبی) استفاده کرد.

the effect of silicon foliar application on some physiological traits of summer savory (satureja hortensis l.) under drought stress

extended abstract introduction: summer savory (satureja hortensis) is an annual herbaceous plant. the leaves of the plant are spear-shaped, opposite, with a short petiole. the leaves and flowering branches of summer savory are used in traditional medicine with known anti-flatulent, anti-heartache, anti-parasitic, stomach tonic, stimulant and expectorant effects. spraying or foliar feeding is a method to reduce the stabilization of chemical fertilizers in the soil and as a result reduce environmental risks, including reducing soil and water pollution. with this feeding method, elements can be provided to the plant as quickly as possible. silicon is the second mineral element in the soil after oxygen, and in higher plants, it usually causes the physical strength of the organs by penetrating the stem and leaves, and also improves physiological and metabolic processes, gas exchanges and strengthens the antioxidant system. also, this element has beneficial effects on the growth, performance and tolerance of some plants against biotic and abiotic stresses. the form of silicon solution in soil is silicic acid si (oh)4. the amount of silicon in plants is 0.1 to 10% of the dry weight of the plant. the use of fertilizers containing silicon in the soil affects growth and development in two ways. first, the improvement of silicon nutrition strengthens the plant’s protection system against adverse environmental conditions. on the other hand, treating soil with compounds containing geochemically active silicon improves the chemical and physical properties of soil and increases the availability of nutrients for plants. the objective of this research was to investigate the influence of silicon application on some physiological and morphological characteristics of summer savory under drought stress conditions.            materials and methods: in order to investigate the effect of silicon foliar application on the summer savory characteristics under deficit irrigation conditions, a factorial experiment was conducted based on randomized complete blocks design with four replications. the experiment was carried out at the vegetable production farm of ardabil municipality during the years 2021-2022. the investigated factors included the first, drought stress at three levels (40, 60, and 80% field capacity (fc)) and the second, silicon foliar spraying at four levels (0 (control), 0.5, 1, and 1.5 mm l-1). drought stress was induced at the stage of 4 to 6 sub-branches and silicon solutions were foliar applied at two stages including a week before the induction of drought stress, and a week after that. distilled water was also used as control treatment. in the present study, pots with a diameter of 20 cm, a height of 30 cm, a capacity of 3 kg with 3 holes at the bottom were used to cultivate savory plants. before the induction of drought stress, the savory plants were regularly irrigated up to the field capacity. drought stress was applied at the stage of 4 to 6 sub-branches based on crop capacity and after the stress induction, sampling was done. results and discussion: the obtained results showed that drought stress negatively affected plant fresh weight, dry weight, height, soluble sugar content, chlorophyll a, b and total and carotenoid content, but proline content increased by 61.03% under highest level of drought stress comparing to control. the highest soluble sugar content was recorded in savory plants sprayed with silicon 1 mm l-1 and grown under drought level of 40% fc (4.76 mg g-1 fw). on the other hand, the lowest value of this trait was obtained in plants treated with silicon 0.5 mm l-1, and grown under drought level of 80% fc (3.16 mg g-1 fw). in the present study, the decrease in chlorophyll of the savory plant under drought stress could be probably related to the increase in the production of oxygen free radicals, peroxidase and phenolic compounds, because the absorption of excess energy by the photosynthetic system often stimulates the production of reactive oxygen species. silicon foliar application had a positive and significant effect on the examined traits, so the negative effects of drought stress were alleviated by increasing silicon concentration. conclusion: in general, it could be stated that silicon could be used as a useful element to increase the performance of agricultural-garden plants, as well as to increase plants tolerance rate against environmental stresses (including drought stress). on the other hand, the application of silicon up to a concentration of 1.5 mm l-1 had a positive effect on alleviation of the adverse effects of deficit irrigation on savory plant characteristics.