تاثیر کاربرد اسید سالیسیلیک و نیتروژن بر غلظت عناصرغذایی در گیاه گندم در سطوح مختلف شوری

شوری یکی از تنش‌های محیطی بسیار مهم است. در شرایط شوری، فرآهمی عناصر غذایی در محلول خاک کاهش یافته و منجر به اختلال در تغذیه و برهم خوردن تعادل عناصرغذایی گیاه می‏گردد. مدیریت کوددهی نیتروژن به عنوان عنصر ضروری برای رشد گیاهان در شرایط تنش شوری بسیار حائز اهمیت است. اسید سالیسیلیک یک تنظیم کننده رشد گیاهی است که در سازوکارهای دفاعی گیاهان در مقابل تنش‌ها دخیل است. به منظور بررسی اثرات اسید سالیسیلیک و سطوح مختلف نیتروژن در شوری‌های مختلفِ اراضیِ شرکت سهامی مزرعه نمونه واقع در انبار الوم شهرستان آق قلا، استان گلستان بر غلظت عناصر غذایی گندم، آزمایشی به‌صورت اسپیلت پلات فاکتوریل در قالب طرح پایه بلوک‌های کامل تصادفی در 4 تکرار انجام شد. فاکتور اصلی شامل سه سطح شوری خاک، ) 43 زیر سطح آستانه تحمل گندم (شاهد)، 119 و 1513 دسی‌زیمنس بر متر) و فاکتورهای فرعی شامل دو سطح اسید سالیسیلک (0 و 1.5 میلی مولار) و سه سطح کود نیتروژن (از منبع اوره 46 درصد) شامل 1) توصیه آزمون خاک، 2) 30% بیشتر از توصیه آزمون خاک و3) 30% کمتر از توصیه آزمون خاک، بود.اسید سالیسیلیک بصورت دو بار محلول پاشی در مرحله پنجه زنی به فاصله حدود 2 هفته انجام شد. تیمارهای نیتروژنی در سه مرحله یک سوم قبل از کاشت از سولفات آمونیوم (21درصد) و دو بار سرک در مراحل پنجه‌زنی و ساقه‏روی از اوره (46درصد) اعمال شد. نتایج نشان داد با افزایش شوری غلظت n برگ پرچم، n و k کاه و دانه گندم کاهش یافت.

The effect of salicylic acid and nitrogen consumption on the concentration of nutrients in wheat at different salinity levels

Introduction Salinity is one of the most important environmental stresses limiting agricultural production in arid and semiarid regions, which occupies a relatively large area of arable land. Nutrient availability is decreased in saline conditions in soil solution and plant nutrient balance is changed. Nitrogen fertilizer management as an essential nutrient for plant growth is very important under salinity stress. Also, salicylic acid is a plant growth regulator involved in defense mechanisms of plants against biotic and abiotic stresses. Therefore, the aim of this study was to investigate the effect of salinity on the concentration of nutrients in wheat in response to salicylic acid consumption at different levels of nitrogen.Materials and Methods In order to investigate the effects of salicylic acid and nitrogen fertilizer application rates at different salinity levels on nutrient concentration of wheat cv. Morvarid, an experiment was conducted as a split plot factorial based on a randomized complete block design with four replications in the fields of MazraehENemooneh located in Anbarolum, Aq Qala city, Golestan province. The main factor included three soil salinity levels (34 below wheat tolerance threshold (control), 911 and 1315 dS.m1) and sub factors included two levels of salicylic acid (0 and 1.5 mM) and three levels of N fertilizer (from urea source, 46% N) were 1) N based on soil test recommendation, 2) 30% N more than soil test recommendation and 3) 30% N less than soil test recommendation, respectively. Salicylic acid was foliar applied twice for about 2 weeks in the tillering stage and 10 days after the second stage spraying, content in them was determined. Nitrogen treatments were applied in three stages one third before planting with ammonium sulfate (21% N) and remains topdressed with urea (46% N) at tillering and stem elongation stages. At the emergence stage of the cluster or the beginning of flowering of wheat, the amount of nitrogen in the flag leaf was measured. The concentrations of nitrogen, potassium and sodium in grain and straw were also measured by standard methods.Results and Discussion The results showed that by increasing salinity, the flag leaf N concentration, N and K concentration of wheat staw and seed decreased. However, Na concentration of straw and seeds increased. With increasing N and salicylic acid consumption, the concentration of N flag leaf, the seed and straw N and K concentrations increased, but the concentration of Na in seed and straw decreased.The interaction of salinity, salicylic acid and nitrogen on seed N and K concentrations and also on flag leaf N concentration was significant but there was no significant effect on other measured elements. Comparison of the mean of simple effects of salinity on the evaluated elements indicates a significant reduction of all studied elements due to salinity treatment. Also, comparison of the mean of simple effects of nitrogen fertilizer showed that all elements were affected by the treatment. The results of mean comparison showed a positive and significant effect of salicylic acid on the leaf N concentration of the flag leaf, so that the N concentration in the flag leaf in a 1.5 mM salicylic acid treatment was significantly increased compared to the nonuse treatment.Conclusion according to the results, more nitrogen consumption at moderate salinity can have a positive effect on plant nutrition, and vice versa, at high salinity levels, it is better to reduce nitrogen consumption. The interactions of salicylic acid and nitrogen showed that in general nitrogen treatments with salicylic acid increased the N concentration of seed and straw. Nitrogen fertilization at higher and medium salinity levels increased the concentration of N and K in straw and seeds; However, at high salinity, less nitrogen fertilization improved the concentration of N and K. Also, nitrogen application with salicylic acid improved these traits under saline conditions. Therefore, the application of salicylic acid and nitrogen fertilizer management to some extent reduced the adverse effects of salinity up to moderate salinity levels and improved plant nutrition by increasing plant tolerance to salinity.Therefore, the application of salicylic acid and nitrogen fertilizer management to some extent reduced the adverse effects of salinity up to moderate salinity levels and improved plant nutrition by increasing plant tolerance to salinity.Key words: Salicylic acid, salinity stress, wheat, Nitrogen fertilizer management