عنوان

ارزیابی مقاومت به خشکی ارقام پائیزه گندم با استفاده از برخی شاخص های فیزیولوژیک، بیوشیمیایی و زراعی

شماره

‭۲۰۴۵پ‬

زبان متن نوشتاري يا گفتاري و مانند آن

per

عنوان اصلي

ارزیابی مقاومت به خشکی ارقام پائیزه گندم با استفاده از برخی شاخص های فیزیولوژیک، بیوشیمیایی و زراعی

نام نخستين پديدآور

/عزت اله اسفندیاری

نام ناشر، پخش کننده و غيره

: کشاورزی

نام خاص و کميت اثر

‮‭۱۵۷‬ ص، جدول، نمودار، عکس، لوح فشرده‬

متن يادداشت

چاپی

متن يادداشت

واژه نامه بصورت زیرنویس

متن يادداشت

کتابنامه ص.: ‮‭۱۳۶-۱۵۷‬

جزئيات پايان نامه و نوع درجه آن

دکتری

نظم درجات

زراعت و اصلاح نباتات

زمان اعطا مدرک

‮‭۱۳۸۶/۰۳/۰۸‬

کسي که مدرک را اعطا کرده

تبریز

متن يادداشت

گندم از اصلی‌ترین محصولات زراعی ایران می‌باشد که بخش قابل توجهی از آن در مناطق دیم تولید می‌گردد .متاسفانه تنش خشکی از عوامل اصلی کاهش عملکرد آن در مناطق خشک و نیمه خشک به شمار می‌آید .به همین دلیل ارقام آذر‮‭۲‬، سبلان، سرداری، الوند و زرین) سه رقم اول در بیشتر مناطق دیم آذربایجان کشت می‌شوند (انتخاب و در شرایط گلخانه‌ای و مزرعه مورد مطالعه قرار گرفتند .در شرایط کنترل شده ارقام گندم به روش هیدروپونیک پرورش و در مرحله‮‭۵‬ - ‮‭۴‬برگی با استفاده از پلی اتیلن گلیکول ‮‭۸۰۰۰‬ در سطوح شاهد،‮‭۴‬ ، ‮‭۸‬ و ‮‭۱۲‬ بار به مدت ‮‭۱۰‬ روز در شرایط تنش نگهداری شدند .نتایج مقایسه میانگین اسکوربات و گلوتاتیون نشان داد که در تمامی ارقام با افزایش تنش اسمزی نسبت‌های‮‭GSSG + GSH/GSH‬و‮‭DHA + ASC/ASC‬کاهش می‌یابد که حاکی از مقابله ارقام با تنش اکسیداتیو می‌باشد .البته در ارقام آذر ‮‭۲‬و سبلان حجم خزانه این آنتی اکسیدان‌ها همزمان با افزایش تنش اسمزی افزایش یافته است

متن يادداشت

Wheat is one of the most important crops in Iran with major production in dry-land farming. Drought stress is one of the main factors of wheat performance reduction in arid and semi arid regions. In the present experiment 5 cultivars of Azar2, Sabalan, Sardari, Alvand and Zarin (three former cultivars are in widespread production in non-irrigated region of East Azarbaijan) were evaluated in greenhouse and filed conditions. Under controlled experiments, wheat cultivars were grown under hydroponic system. 4-5 leaf bearing plants were incubated under drought conditions with control, 4, 8 and 12 bars of PEG8000 for 10 days. Mean comparison for ascorbat and glutathione showed that in all cultivars increase in osmotic stress was concomitant with decrease in GSH/GSH+GSSG and ASC/ASC+DHA leading to tolerance to oxidative stress. However, in Azar2 and Sabalan pool size of these antioxidants increased with promoting osmotic stress.The results showed that there was a negative relationship between antioxidants activity, antioxidant enzymes and membrane damage. Furthermore, successful ROS scavenging is dependent on cooperative activity of diverse enzymes, and activity reduction of any of key enzymes would be a potential to plant cell damage. Moreover, the results showed that antioxidants such as ascorbate and glutathione have direct ROS scavenging potential. This criterion logically demonstrates the paradox of un-damaged membranes under low activity of a key enzyme such as SOD in Azar2 cultivar. In Azar2, Sabalan and Sardari, GR activity was not a limiting factor as well, because, as a general rule, increased osmotic stress levels invariably accompanied higher activity of this enzyme.Maximum electron transport efficiency of photosystem II for wheat cultivars was constant for all osmotic stress levels. This result was proved with constant ratio of chlorophyll a/b, and increase in carotenoid and praline amounts. This is due to this fact that, carotenoids have high activity in xanthophyll cycle and prevents ROS production. Furthermore, ROS scavenging activity system in chloroplast is not a limiting factor. For this reason, in these cultivars, other ROS producing organelles are their weak-point. In total, the results obtained from seedling stage experiments showed that Alvand, Sardari and Zarin were sensitive to PEG8000derived osmotic stress. Meanwhile, Azar2 and Sabalan had higher tolerance to osmotic stress due to their physiological and biochemical characteristics. The results obtained from the analysis of wheat plant characteristics showed that biological and economical yield of main stem and wheat tillers was declined under drought stress. Meanwhile, reduction in tillers was greater than that of main stems. So that under drought stress biological and economical yields of main stems was higher than that of minor tillers and these organs had efficient share in total yield. The results obviously indicate the relationship between the plant weakness under drought stress and yield loss. Therefore, first tillers yield comprised about 10-15 of economical yield of total plant. But other tillers had minor role in plant yield and only had promotive effects on biological yield and plant debrises. Drought stress had promotive effects on physiological ripening of studied cultivars by shortening of grain filling period, because optimum vegetative growth of cultivars have been occurred under suitable water conditions. Furthermore, non-irrigation conditions, plant height was decreased in flag leaf emergence stage due to the peduncle length reduction. In this stage peduncle is not in full length, and concomitant with reduced growth, assimilates stream to the spikes. The results showed that dependent on the environmental conditions, plants send assimilates to different definite destinations. However, under stress conditions, these metabolites take way to organs involved in grain production and economical yield. Furthermore, under drought stress conditions source limitation led to yield loss in studied wheat cultivars. Sardari cultivar had same yields under normal and stress conditions and this trend shows source limitation in this cultivar. Drought stress in both phonological stages increased unfertilized spiklet numbers. This phenomenon shows the reduced photoasimilation production or emberyo abortion due to the low nutrients arability. This result also strengthens the source limitation under drought stress conditions.Unaffected electron transport efficiency under drought stress conditions in wheat plants completely reflects the plant anatomical structure effects on the induction of tolerance to environmental stresses. Wheat plants respond to these extreme conditions especially high light conditions with lead rolling, changing leaf angle related to stem and shifting leaf color from green to silver and hence preserve thylakoids from significant damage. Sardari cultivar had the highest yield stability under different stress levels. Meanwhile in Azar2, Alvand and Sabalan cultivars, irrigation stop time had no effect on yield.

موضوع مستند نشده

Antioxidant

موضوع مستند نشده

Antioxidant enzyme

موضوع مستند نشده

Drought stress

موضوع مستند نشده

Lipid peroxidation

موضوع مستند نشده

Oxidative stress

موضوع مستند نشده

Wheat

مستند نام اشخاص تاييد نشده

اسفندیاری، عزت اله

مستند نام اشخاص تاييد نشده

شکیبا، محمدرضا، استاد راهنما

مستند نام اشخاص تاييد نشده

محبوب، سلطانعلی، استاد راهنمای همکار

مستند نام اشخاص تاييد نشده

آلیاری، هوشنگ، استاد مشاور

مستند نام اشخاص تاييد نشده

تورچی، محمود، استاد مشاور همکار

وضعیت فهرست نویسی

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