اثر غلظت‌های مختلف سلنیوم بر خصوصیات جوانه‌زنی و محتوای پرولین گیاه کینوا (chenopodium quinoa willd) تحت تنش خشکی

پرایمینگ بذر روشی موثر جهت افزایش عملکرد بذر و بهبود تحمل محصولات زراعی نسبت به تنش‌های غیر زیستی بویژه خشکی می‌باشد. به منظور بررسی غلظت‌های مختلف سلنیوم (na2seo3) در شرایط تنش خشکی آزمایشی به صورت فاکتوریل با 5 سطح پرایمینگ با سلنیوم از منبع سلنیت سدیم (0.5، 1.5، 3، 4.5 و 6 میلی‌گرم در لیتر)، و دو سطح هیدروپرایمینگ و بدون پرایمینگ و سه سطح تنش خشکی با استفاده از پلی اتیلن گلایکول (peg) (0.4، 0.8 و 1.2 مگاپاسگال) با سه تکرار در آزمایشگاه تکنولوژی بذر دانشکده علوم کشاورزی دانشگاه شاهد در سال 1398 انجام گرفت. نتایج نشان داد که پرایم با سلنیوم و اعمال تنش خشکی اثر معنی‌داری بر اکثر صفات جوانه‌زنی و رنگیزه‌های فتوسنتزی، میزان پرولین و آنزیم کاتالاز داشت. پرایم با سلنیوم در غلظت مناسب آن منجر به ظهور سریعتر گیاهچه در شرایط تش خشکی شد ولی با افزایش غلظت سلنیوم و همچنین افزایش سطوح تنش خشکی اثر بازدارنده‌ای را نشان داد. پیش تیمار با سلنیوم در غلظت 3 میلی‌گرم در لیتر بیشترین درصد جوانه‌زنی (94%)را با افزایشی 58 درصدی نسبت به تیمار عدم پرایمینگ و تنش شدید نشان داد. همچنین گیاهچه‌های که با سلنیوم پرایم شده بودند رنگیزه‌ی فتوسنتزی بیشتری را نسبت به عدم پرایمینگ و هیدورپرایم در شرایط تنش داشتند. بیشترین میزان پرولین و کاتالاز را در شرایط تنش شدید به ترتیب با غلظت 0.5 و 1.5 میلی‌گرم در لیتر مشاهده شد. بنابراین جهت بهبود جوانه‌زنی و رشد اولیه گیاهچه کینوا می‌توان با پرایمینگ بذر با استفاده از سلنیوم به نتیجه بهتری رسید.

Effect of different concentrations of selenium on germination characteristics and proline content of quinoa (Chenopodium quinoa willd ) under drought stress

IntroductionDrought stress is a major constraint to agricultural productivity all around the world. Drought is the most significant threat to global food security. Food demand becomes a huge issue because water supply is restricted around the planet. Plant seed priming is a simple, lowcost, lowrisk, and effective way to boost plant tolerance under stressful situations.In nutrient priming, seeds are pretreated (primed) in solutions containing the limiting nutrients instead of being soaked just in water. Microelements, which are required in very small quantities, play important roles in improving crop productivity and quality. Oxidative stress is caused by the formation of active oxygen species (ROS) in response to water stress. Antioxidant enzymes are regarded to be the &first line of defense& against reactive oxygen species (ROS) produced by a variety of environmental injury species. Selenium’s strategies for decreasing the effects of drought are mostly antiantioxidant defense activation. Quinoa (Chenopodium quinoa Willd) is a stresstolerant pseudo cereal that has been cultivated for over 7000 years in the Andes, in a variety of environments, with Peru and Bolivia being the main producers. Quinoa is a highprotein food (1216.5 percent), with protein quality comparable to casein. Furthermore, this &wonder grain& is glutenfree and high in bioactive substances such as antioxidants, polyphenols, flavonoids, vitamins, and minerals that imparts various health benefiting characteristics to this grain. Quinoa plants, including seeds and leaves, can be eaten to provide nutrition to humans and animals. Quinoa is also great for digestion because it has twice the amount of nutritional fibre as other cereals. Materials and MethodsThus a factorial experiment in a completely randomised design with three replications was conducted in the Seed Technology Laboratory, Faculty of Agricultural Sciences, Shahed University in 2020 to investigate the effect of sodium selenite pretreatment on germination indices and prolin content of quinoa plants under drought stress. The variables in the experiment Include four levels of sodium selenite (0.5, 1.5, 3, 4.5, and 6 mg/lit), two levels of hydroprimind and no priming, and three levels of drought stress induced by polyethylene glycol (0.4, 0.8, and 1.2 MP). Germination percentage (GP), mean germination time (MGT), germination speed (GR), and SVI: seedling longitudinal index, seedling length, changes in the number of photosynthetic pigments, and proline content, and Catalase enzyme levels were among the traits that were assessed. Statistical analysis of the data included analysis of variance using AS 9.1 software and comparison of the mean of traits evaluated by LSD test at 5% probability level. ResultsThe results showed that prime with selenium and drought stress had a significant effect on most germination traits and photosynthetic pigments, proline levels and catalase enzyme. Prime with selenium at its proper concentration led to the early emergence of seedlings in droughttolerant conditions, but showed an inhibitory effect by increasing the concentration of selenium and increasing the levels of drought stress. Pretreatment with selenium at 30 mg / L showed the highest percentage of germination (94%) with a 58% increase compared to nonpriming and severe stress treatment. Also, seedlings that were primed with selenium had more photosynthetic pigments than nonpriming and hydrophilicity under stress. The highest levels of proline and catalase were observed in extreme stress conditions with molar concentrations of 1.5 and 1.5 mg/lit, respectively. As a result, seed priming with selenium can be used to boost quinoa seedling germination and early growth under field circumstances.