@article { author = {Parsajoo, S. and Dashti, F.}, title = {The Effect of Ascorbic Acid on Growth and Some Biochemical Properties of Bell Pepper (Capsicum annuum) Seedling under Salinity Stress}, journal = {Journal Of Horticultural Science}, volume = {37}, number = {2}, pages = {497-508}, year = {2023}, publisher = {Ferdowsi University of Mashhad}, issn = {2008-4730}, eissn = {2423-3986}, doi = {10.22067/jhs.2022.77340.1182}, abstract = {Introduction  Plants are sometimes exposed to several stresses during their growth and development. Salinity stress is one of the most common abiotic stresses that significantly reduces the growth and yield of most plant species. A large part of the soils and a significant volume of all water resources in Iran are affected by salinity to varying degrees. Due to the rapid population growth and the need for more food and the water crisis, the use of unconventional water such as salt water or wells and treated wastewater in agriculture has received more attention. Soil and water salinity is one of the integrative problems in agriculture and is one of the most important barriers to crop production in the world. Salinity stress reduces the ratio of carbon dioxide to oxygen in the leaves by closing the leaves stomata and prevents the stabilization of carbon dioxide. Under these conditions, the formation rate of reactive oxygen species in chloroplasts and mitochondria increases, the electrons produced react with oxygen by photosynthesis and lead to the production of oxygen free radicals. These affects the growth, yield and quality of agricultural products. The use of antioxidant compounds can moderate the effects of this stress. Many compounds have been used to reduce the harmful effects of salinity stress. Ascorbic acid is a water soluble antioxidant and has some effects on plant resistance against environmental stresses by neutralizing free radicals. Researches showed that ascorbic acid increased plant resistance on various stresses such as salinity and drought. It has been widely used to control the effects of salinity stress. The aim of this study was to investigate the effect of ascorbic acid on resistance to salinity stress in bell pepper seedlings.   Materials and Methods  This study was done as a factorial experiment in a completely randomized design including ascorbic acid treatment (0, 1, 3 and 5 mM) and salinity stress of sodium chloride (0 and 100 mM) in 3 replications. The seeds of bell pepper Cv. California Wonder were planted in a seedling tray containing cocopeat. After emergence of cotyledons, they were fertilized with complete fertilizer (N20, P20, K20). At the stage of three true leaves the  salinity treatment were started. One week before the beginning of salinity treatment, ascorbic acid was sprayed on plants and repeated two more times by seven days interval. Salinity treatment was applied by irigation for three weeks. After producing 5 leaves, a few growth properties (plant fresh and dry weight, root fresh and dry weight, leaf number and leaf area), biochemical characteristics (amounts of total chlorophyll, proline, soluble proteins, ion leakage and malondialdehyde and activity of Catalase an Proxidase enzymes) and amounts of some elements (K, P, Na, Fe, Zn and Cu) were measured.   Results and Discussion  Based on the results, the simple effect of salinity stress, ascorbic acid and the combined effect of them on ion leakage and amounts of malondialdehyde were significant at the level of 1% probability. Salinity stress increased the amounts of ion leakage and malondialdehyde and application of 5 mM ascorbic acid reduced the amount of these traits to 41.01% and 46.58% compared to the control respectively. The effect of salinity stress, ascorbic acid and the combined effect of them on the concentration of proline and chlorophyll in the leaves of bell pepper were significant at the level of 1% probability. Salinity stress increased the amount of proline but decreased chlorophyll and leaf protein of pepper seedlings and application of 5 mM ascorbic acid increased them to 79.42% and 46.57% compare to control respectively. Under salinity stress the uptake of iron, zinc, copper and phosphorus decreased; using of 5 mM ascorbic acid increasing accumulation of these elements in leaves .On the other hand ascorbic asid could decrease the amounts of sodium accumulation in seedling,s leaves. The results showed that, salinity decreased growth indices (number of leaves, leaf surface, fresh weight of roots and plants) and ascorbic acid reduced the effect of salinity stress on growth parameters. Under salinity stress, 5 mM ascorbic acid treatment increased the leaf surface to 36.30% compared to salinity without ascorbic acid tretment. The effects of salinity stress and the combined effect of salinity stress and ascorbic acid on the amount of catalase and peroxidase enzymes were significant at the level of 1% probability. The effect of ascorbic acid was significant for catalase at 5% probability level and peroxidase at 1% probability level. Although salinity increased the amounts of the antioxidant catalase and peroxidase enzymes but ascorbic acid could increased the activity of them in saline condition.   Conclusion  It seems that application of ascorbic acid as an antioxidant could reduce the effects of salinity stress by increasing the activity of catalase and peroxidase enzymes, reducing sodium uptake and increasing the uptake of phosphorus, potassium, iron, zinc and copper. These could have positive effects on the growth parameters of bell pepper seedlings in salinity conditions. Generally, on based of obtained results, spraying 5 mM Ascorbic acid on bell pepper seedlings modified the resistance of them in salinity stress conditions.}, keywords = {Antioxidant enzymes,Chlorophyll,Proline,Sodium Chloride}, title_fa = {اثر اسید آسکوربیک بر رشد و برخی ویژگی‌های بیوشیمیایی نشاء فلفل دلمه‌ای (Capsicum annuum) تحت تنش شوری}, abstract_fa = {شوری خاک و آب یکی از مشکلات در حال افزایش کشاورزی و از مهم‌ترین موانع تولید محصول در جهان است. ترکیبات زیادی در زمینه کاهش اثرات زیان آور تنش شوری مورد استفاده قرار گرفته است. اسید آسکوربیک آنتی‌اکسیدان محلول در آب می‌باشد که با بی اثر کردن رادیکال‌های آزاد موجب مقاومت گیاهان در برابر تنش‌های محیطی می‌شود. در این پژوهش تأثیر اسید آسکوربیک بر کاهش اثرات شوری در تولید نشاء گیاه فلفل دلمه‌ای در شرایط کشت گلخانه‌ای مطالعه شده است. این آزمایش به صورت فاکتوریل در قالب طرح کاملاً تصادفی در دو سطح نمک کلرید سدیم (صفر و 100 میلی‌مولار) در آب آبیاری و چهار سطح اسید آسکوربیک (صفر، یک، سه و پنج میلی‌مولار) با سه تکرار انجام شد. نتایج نشان داد تنش شوری موجب افزایش نشت یونی و تولید مالون‌دی‌آلدئید شد و کاربرد اسید آسکوربیک در غلظت 5 میلی­مولار موجب کاهش میزان این صفات در شرایط تنش شوری شد. تنش شوری موجب افزایش میزان پرولین و کاهش کلروفیل کل و پروتئین برگ نشاء فلفل دلمه‌ای شد در حالی‌که کاربرد اسید آسکوربیک با غلظت 5 میلی‌مولار موجب افزایش صفت‌های نام برده شد. از طرف دیگر در گیاهان تحت تنش شوری جذب عناصر آهن، روی، مس و فسفر کاهش و سدیم افزایش یافت که کاربرد اسید آسکوربیک باعث افزایش تجمع سه عنصر اول و کاهش تجمع سدیم در برگ گیاهان شد. از نظر شاخص‌های رشد، تنش شوری باعث کاهش صفات رشدی (تعداد برگ، سطح برگ، وزن تر ریشه و برگ) شد و تیمار با اسید آسکوربیک اثر تنش شوری را بر پارامترهای رویشی کاهش داد بطوری‌که تحت تنش شوری، تیمار اسید آسکوربیک 5 میلی­مولار توانست سطح برگ را نسبت به تیمار شوری بدون کاربرد اسید آسکوربیک افزایش دهد. از طرف دیگر کاربرد اسید آسکوربیک باعث افزایش فعالیت آنزیم‌های آنتی‌اکسیدانی کاتالاز و پراکسیداز شد. به‌طور کلی با توجه به نتایج حاصله می‌توان گفت محلول‌پاشی با غلظت 5 میلی‌مولار اسید آسکوربیک در نشاء گیاه فلفل دلمه‌ای باعث بهبود مقاومت به شرایط تنش شوری می‌شود.}, keywords_fa = {آنزیم های آنتی اکسیدان,پرولین,کلروفیل,کلرید سدیم}, url = {https://jhs.um.ac.ir/article_42695.html}, eprint = {https://jhs.um.ac.ir/article_42695_042b476a85b26ac803c06d574b0a08df.pdf} }