Leaf rolling (LR), particularly in crops, is a dehydration avoidance mechanism that results from water loss in plants under drought conditions. Two maize cultivars (Zea mays L.) differing in their tolerance to drought (cultivar Side was selected as stresstolerant and cultivar Karaçay was selected as stress-sensitive) under PEG-induced drought stress were used in this study to understand the effects of polyamines (PAs) on LR response and the role of the antioxidant system in the delayed LR process. | Turkish Journal of Biology Research Article Turk J Biol (2017) 41: 563-574 © TÜBİTAK doi: Exogenously applied polyamines ameliorate osmotic stress-induced damages and delay leaf rolling by improving the antioxidant system in maize genotypes 1, 2 3 Nihal KUTLU ÇALIŞKAN *, Asım KADIOĞLU , Neslihan SARUHAN GÜLER 1 Breeding and Genetics, Central Fisheries Research Institute, Trabzon, Turkey 2 Department of Biology, Faculty of Science, Karadeniz Technical University, Trabzon, Turkey 3 Department of Nutrition and Dietetics, Faculty of Health Sciences, Karadeniz Technical University, Trabzon, Turkey Received: Accepted/Published Online: Final Version: Abstract: Leaf rolling (LR), particularly in crops, is a dehydration avoidance mechanism that results from water loss in plants under drought conditions. Two maize cultivars (Zea mays L.) differing in their tolerance to drought (cultivar Side was selected as stresstolerant and cultivar Karaçay was selected as stress-sensitive) under PEG-induced drought stress were used in this study to understand the effects of polyamines (PAs) on LR response and the role of the antioxidant system in the delayed LR process. Aerial parts of the seedlings were excised prior to the experiment and then submerged in a Hoagland nutrient solution with or without mM Putrescine and mM Spermine for 17 h, after which they were submitted to osmotic stress treatments (5% PEG) for 24 h. LR was physically prevented in order to clarify the relationship between PAs and antioxidant systems in LR response. Plants were evaluated by measuring the accumulation of hydrogen peroxide (H2O2), lipid peroxidation, antioxidant enzyme activities, and nonenzymatic antioxidant levels. Exogenous applications of PAs prevented water loss and delayed LR in comparison with the control (seedlings treated only with PEG). PAs almost totally prevented increases in lipid .
