پديد آورندگان :
وهبي،ندا دانشگاه شيراز - دانشكده كشاورزي - بخش زراعت و اصلاح نباتات , امام، يحيي دانشگاه شيراز - دانشكده كشاورزي - بخش زراعت و اصلاح نباتات , پيرسته انوشه، هادي سازمان تحقيقات، آموزش و ترويج كشاورزي يزد - مركز ملي تحقيقات شوري
چكيده فارسي :
هر چند تاثير مفيد كاربرد تنظيم كننده هاي رشد در شرايط تنش خشكي به طوركلي پذيرفته شده است، ليكن، انجام پژوهش هاي كاربردي با هدف مقايسه انواع تنظيم كننده ها براي بهينه كردن مصرف آن ها ضرورت دارد. به منظور بررسي اثر سه تنظيم كننده رشد كلرمكوات كلرايد، ساليسيليك اسيد و جاسمونيك اسيد بر عملكرد و اجزاي عملكرد گندم رقم روشن تحت شرايط متفاوت تنش رطوبتي (دامنه اي از شدت هاي ملايم تا شديد خشكي) پژوهشي در دو شرايط كنترل شده و مزرعه در دانشكده كشاورزي دانشگاه شيراز انجام شد. آزمايش هاي گلخانه اي و مزرعه اي به ترتيب به صورت آزمايش فاكتوريل در قالب طرح كاملا تصادفي و آزمايش كرت هاي يك بار خردشده بر پايه بلوك هاي كامل تصادفي انجام شد. نتايج نشان داد كه اعمال تنش رطوبتي و افزايش شدت آن سطح برگ پرچم، طول سنبله، تعداد دانه در سنبله، عملكرد بيولوژيك و عملكرد دانه را كاهش داد، ليكن كاربرد تنظيم كننده هاي رشد سبب بهبود همه اجزاي عملكرد دانه و در نهايت افزايش عملكرد دانه گرديد. با اين وجود، تاثير كلرمكوات كلرايد از ساليسيليك اسيد و جاسمونيك اسيد بيشتر بود، به طوري كه محلول پاشي اين سه تنظيم كننده با افزايش عملكرد دانه به ترتيب به مقدار 20/7، 13/8 و 7/24 درصد در آزمايش گلخانه اي و به مقدار 18/3، 12/2 و 8/1 درصد در آزمايش مزرعه اي همراه بود. به طور كلي، نتايج نشان داد كه گرچه تنش رطوبتي عملكرد دانه گندم را كاهش داد، ليكن تنظيم كننده هاي رشد توانستند بخشي از اين افت عملكرد را جبران كنند. به علاوه، محلول پاشي كلرمكوات كلرايد قابليت بررسي بيشتري را به عنوان رهيافتي براي افزايش توليد در شرايط محدوديت رطوبت داراست.
چكيده لاتين :
Introduction Drought stress is most important abiotic stress reducing growth and production of wheat worldwide. Protective role of plant growth regulators (PGRs) against drought stress has been accepted in general, however, comparison of PGRs types to determine the optimum one is crucial. Many PGRs are known to alleviate the negative effects of drought stress in plants. However, limited research has been conducted to investigate the potential benefits of exogenous application of different PGRs in wheat plants grown under drought stress. Chlormequat chloride (CCC), salicylic acid (SA) and jasmonic acid (JA) could consider as three major PGRs using in cereals. Materials and Methods To examine the effect of three PGRs consisted of CCC, SA and JA on yield components and grain yield of wheat cv. Roshan under different water stress conditions (a range of light to severe drought levels) two separated experiments were conducted at controlled and field conditions at College of Agriculture, Shiraz University during 2012-2013 growing seasons. Concentration of CCC, SA and JA were 19.0, 1.0 and 0.1 mM, respectively. Drought stress levels were 100%, 80%, 60% and 40% of field capacity in greenhouse and were 100%, 2/3 and 1/5 of field capacity in the field experiment. Field capacity was determined as 25% (g g-1) for the experimental field. Greenhouse and field researches were carried out in factorial experiment based on completely randomized design and in split plot experiment based on randomized complete block design, respectively. Four and three replications were used greenhouse and field experiments, respectively. Roshan as a bread wheat cultivar with standard height was used. Foliar application of 3 PGRs was done at double ridges stage in both experiments; however, irrigation treatments were applied at double ridges stage and early anthesis at greenhouse and field experiment, respectively. For plot irrigation a tape system was used and amount of irrigation was measured by a water meter. Results and Discussion The results sho Similarly, SA application may result in stomatal closure, increased WUE, increased chlorophyll content, increased respiratory-pathways and intercellular CO2 concentration, and stimulatory changes in other physiological and biochemical attributes. Jasmonic acid is also essential components for the signaling pathway triggering the expression of plant defense genes in response to abiotic stresses. This PGR had a significant role in osmotic adjustment under drought stress conditions. Conclusions Overall, drought stress depending on time and severity of application had several adverse effects on wheat
cultivar including decreased flag leaf area, ear length and grain number which led to reduced biological yield and grain yield. However, exogenous application of SA, CCC or JA reduced at least some of the harmful impacts of drought stress and in some cases compensated losses or damages caused by the drought, resulting in purging of
differences between the control and drought stress conditions. Furthermore, chlormequat chloride might have a wide scope for further investigations as an approach to increase grain yield under limited water conditions.
