بررسي تغييرات برخي آنتي اكسيدان ها در ژنوتيپ هاي كنجد و ارتباط آن با صفات فيزيولوژيك تحت شرايط تنش شوري در كشت هيدروپونيك

چكيده انگليسي :

Evaluationof Interrelations of Some Antioxidants and Physiological Characteristics of Sesame Genotypes Under a Saline Hydroponic Culture Amirhossein Bazrafshan Amir bazrafshan 65@yahoo com May 10 2011 Department of Agronomy and Plant Breeding College of Agriculture Isfahan University of Technology Isfahan Iran 84156 83111 Degree M Sc Language Farsi Supervisor Parviz Ehsanzadeh ehsanp@cc iut ac ir AbstractSoil salinity is one of the major environmental constraint for agricultural crops in 20 of total arable land andnearly 50 of irrigated lands worldwide Salinity may affect plant growth development and many physiologicalfunctions due to both harmful ion effects and water deficit stress caused by a reduced osmotic potential in thesoil solution Saline and sodic soils are expanding especially in arid and semiarid regions of the world salineand alkaline soils account for 12 5 of agricultural lands in Iran In order to evaluate the effect of salt stress onnet photosynthetic rate A stomatal conductance to the CO2 gs substomatal CO2 concentration Ci leaveschlorophyll content quantum efficiency of PS II Fv Fm antioxidant enzymes activity lipid peroxidation LP leaves proline content and cation concentration in shoots of sesame genotypes an experiment was conductedunder greenhouse conditions using a hydroponic nutrient solution at the College of Agriculture IsfahanUniversity of Technology Isfahan Iran during April Aguest 2010 The experiment was arranged as a factorialbased on a randomized complete block design with three replications Seven sesame Sesamum indicum L genotypes Naz Takshakhe Naz Chandshakhe Ardestan Varamin Yekta Darab and Oltan were treated bythree levels of salinity including 0 control 30 and 60 mM NaCl during the vegetative stage All measurementswere made at week 5 after application of NaCl to the hydroponic medium Catalase CAT AscorbatePeroxidase APX Glutathione Reductase GR and Superoxide Dismutase SOD activities increased under 60mM level of salinity by 31 5 56 75 5 and 37 8 respectively compared to the control treatment Leaf prolinecontent of sesame genotypes increased with salinity the highest increase 95 5 was observed in 60 mM levelof the salinity Severe salinity led to significant decreases in A 64 24 gs 63 2 total chlorophyll content 30 6 and Fv Fm 11 8 While under severe salinity significant decreases in potassium 47 8 calcium 44 2 and magnesium 42 06 contents were observed a 6 5 fold increase in sodium content in shoots ofsesame genotypes was detected compared to the control Furthermore a 15 3 fold increase in K Na ratio wasobserved at 60 mM level of salinity compared to the control treatment The greatest decrease in A gs and LPalong with the decrease in CAT and SOD activities under salinity was observed in Naz Takshakhe Naz Chandshakhe and Oltan leading to a lower resistance to salinity stress in these genotypes While severe salinityincreased the level of all antioxidant enzymes in more resistant genotypes it decreased the activity of CAT andSOD in more susceptible genotypes It seems that in Ardestan Varamin and Darab increases in CAT and SODactivities along with the stability of cell membrane led to the resistance to salinity stress in latter genotypes Itcan be concluded that activation of antioxidant defence in some sesame genotypes plays a key role in resistanceto the salt stress Furthermore these results suggest that the salinity may leave significant negative effects ongrowth development and physiological attributes of sesame plants and the responses may vary with sesamegenotypes Key words Salinity Sesame Proline Antioxidant enzymes Lipid peroxidation Photosynthesischaracteristics

بذرافشان، اميرحسين

بررسي تغييرات برخي آنتي اكسيدان ها در ژنوتيپ هاي كنجد و ارتباط آن با صفات فيزيولوژيك تحت شرايط تنش شوري در كشت هيدروپونيك

پرولين , پراكسيداسيون ليپيد , خصوصيات فتوسنتزي