مطالعه تحمل به شوری گیاهان باززایی شده از ریشه تنباکو (.nicotiana rustica l)

در شرایط تنش، گونه های فعال اکسیژن (ros) در برگ ها تجمع پیدا می کند و به اکسیداسیون ترکیبات مهم سلولی مثل پروتئین، کلروفیل، لیپید و اسیدهای نوکلئیک منجر می شود. در این پژوهش گیاهان باززایی شده از ریشه تنباکو و گیاهان غیرباززایی شده به مدت 4هفته در محیطms حاوی غلظت های صفر، 100، 200 میلی مولارnacl رشد داده شدند و سپس شاخص های رشد از جمله وزن تر و خشک، میزان رنگیزه های فتوسنتزی شامل کلروفیل کل و کاروتنوئید، غلظت های سدیم و پتاسیم، میزان فنل کل، میزان پرولین، میزان آنتی اکسیدانی کل، میزان ros کل، میزان پراکسیداسیون لیپیدها، میزان اکسین و همچنین آنالیز rapid - pcr مورد بررسی قرارگرفت. مشاهده شد وزن تر و خشک گیاهان باززایی شده افزایش معنی داری را نسبت به گیاهان غیر باززایی نشان داد. همچنین افزایش میزان رنگیزه ها و نیز کاهش سدیم و افزایش پتاسیم و کاهش ros کل و mda و افزایش آنتی اکسیدانی کل و اکسین نیز نسبت به گیاهان غیرباززایی در شرایط شوری مشاهده شد. نتایج به دست آمده از آنالیز rapid - pcr وجود تنوع سوماتیکی را در گیاهان باززایی شده نسبت به گیاهان غیرباززایی نشان داد. تحقیق حاضر نشان می دهد گیاهان باززایی شده می توانند باعث افزایش مقاومت به شوری و بهبود شاخص های رشد در شرایط شوری شوند.

the study of salt tolerance in regenerated plants from the roots of tobacco (nicotiana rustica l.)

introductionsoil salinity as a limiting factor for plant growth and development and one of the environmental stresses that has attracted the attention of scientists. nacl reduces seed germination percentage, root length, fresh weight and dry weight of seedlings and fresh weight of hypocotyl. salinity stress inhibits plant growth and development and reduces photosynthesis, respiration and protein synthesis in susceptible species. when plants are exposed to environmental stresses such as salinity and drought, the balance between the production of reactive oxygen species (ros) and the activity of interfering systems in the clearance of these radicals by antioxidants is disturbed and ultimately oxidative damage. the reactive oxygen species (ros) accumulates in the leaves and lead to the oxidation of important cellular constituents such as protein, chlorophyll, lipid and nucleic acids. salt tolerance increases if free radicals are produced through the intensification of the antioxidant system. there is a relationship between oxidative depletion and increased tolerance to salt and other environmental stresses and the efficiency of the antioxidant system. plants use complex antioxidant systems that reduce the oxidative damage caused by ros to cellular parts. this system controls the amount of ros under both natural and environmental stressful conditions, without which plants can not convert solar energy in to chemical energy all plant body cells have the ability to regenerate, that is, to proliferate or create a new plant. in fact, regeneration is the basis of plant tissue culture, which means creating a complete plant with roots and stems from undifferentiated plant cells. regeneration of plants by culturing undifferentiated cells in this in vitro is a clear reason for the flexibility of plant cells that occurs in response to specific environmental signals.materials and methodsin this study, root regenerated plants as well as unregenerate plants from tobacco roots were cultured in ms medium containing concentration of zero, 100, 200 mm nacl were grown 4 a weeks and then growth indicators of including fresh and dry weight, photosynthetic pigments content including total chlorophyll and carotenoids, concentration sodium and potassium, total phenol content, proline content, total antioxidant level, total ros, lipid peroxidation, auxin content as well as rapidpcr analysis got it.results and discussionit was observed that fresh and dry weight of regenerated plants increased significantly over nonregenerated plants showed. it also increased the amount of photosynthetic pigments and reduced sodium and increased potassium, decreased total ros and mda and increased total antioxidant and auxin also relative to nonregenerated plants were observed in salt conditions, results obtained from rapidpcr analysis it showed somatic variation in regenerated plants comared to nonregenerated plants. present research suggests that regenerated plants can enhances improved salinity resistance growth indices in saline conditions. in general, the results show that regenerated plants in both nonstress and salinity stress improved growth, physical and biochemical indices compared to nonregenerative plants. it was also found that regenerated plants r2 had better performance under salinity stress than plants regenerated plants r1 and nonregenerated plants. the occurrence of somaclonal variations between regenerated and nonregenerated plants has also been identified.conclusioni n the present study, from regenerated and non regenerated tobacco roots were cultured in ms medium containing concentration of zero, 100, 200 mm nacl were grown 4 a weeks. the photosynthetic pigments were incresed while, sodium content reduced but  potassium was increased, total ros decreased and mda increased, total antioxidant and auxin also relative to nonregenerated plants were observed in salinity conditions. results obtained from rapidpcr analysis showed somaclonal variation in regenerated plants comared to nonregenerated plants. present data suggested that regenerated plants from root improved salinity tolerance and growth parameters in saline conditions.