This study examined the influence of drought stress during the flowering stage of 2 canola cultivars on some physiological characteristics, antioxidant activities, and gene expression of antioxidant enzymes. Significant differences were observed among interactions of cultivars and levels of drought stress in total shoot dry material, relative water content percentage, proline, carbohydrates, gene expression, and activities of antioxidant enzymes. | Turkish Journal of Agriculture and Forestry Research Article Turk J Agric For (2015) 39: 413-420 © TÜBİTAK doi: Physiological characteristics, antioxidant enzyme activities, and gene expression in 2 spring canola (Brassica napus L.) cultivars under drought stress conditions Seyed Mohammad HOSSEINI, Tahereh HASANLOO*, Saeed MOHAMMADI Department of Molecular Physiology, Agricultural Biotechnology Research Institute of Iran, Karaj, Iran Received: Accepted: Published Online: Printed: Abstract: This study examined the influence of drought stress during the flowering stage of 2 canola cultivars on some physiological characteristics, antioxidant activities, and gene expression of antioxidant enzymes. Significant differences were observed among interactions of cultivars and levels of drought stress in total shoot dry material, relative water content percentage, proline, carbohydrates, gene expression, and activities of antioxidant enzymes. Moreover, a significant positive correlation was indicated between shoot dry materials with relative water content percentage, sucrose, catalase activity, ascorbate peroxidase activity, and cytosolic ascorbate peroxidase relative gene expression ratio. Antioxidant enzymatic activity and the association between gene transcript levels and activity seem to play roles in protecting plants from oxidative damage in drought stress. The lowest ascorbate peroxidase activity was measured under normal conditions in the cultivar Option (409 nmol ascorbate oxidation per min/g protein), and the highest ascorbate peroxidase was observed in RGS003 (600 nmol ascorbate oxidation per min/g protein) in high stress. Additionally, in the case of relative gene expression ratio the lowest cytosolic ascorbate peroxidase was observed under normal conditions in Option (), and the highest cytosolic ascorbate peroxidase was seen in RGS003 () in
