tailieunhanh - Antioxidative potentials as a protective mechanism in Catharanthus roseus (L.) G.Don. plants under salinity stress

Antioxidant responses were analysed in Catharanthus roseus (L.) . under 0, 50 and 100 mM NaCl in order to investigate the plant’s protective mechanisms against long-term salt-induced oxidative stress. The NaCl treatments were repeated in 4 different stages of growth, . 30, 45, 60 and 75 days after sowing (DAS). | Turk J Bot 31 (2007) 245-251 © TÜB‹TAK Research Article Antioxidative Potentials as a Protective Mechanism in Catharanthus roseus (L.) . Plants under Salinity Stress Cheruth Abdul JALEEL, Ragupathi GOPI*, Paramasivam MANIVANNAN, Rajaram PANNEERSELVAM Stress Physiology Lab, Department of Botany, Annamalai University, Annamalainagar 608 002, Tamil Nadu - INDIA Received: Accepted: Abstract: Antioxidant responses were analysed in Catharanthus roseus (L.) . under 0, 50 and 100 mM NaCl in order to investigate the plant’s protective mechanisms against long-term salt-induced oxidative stress. The NaCl treatments were repeated in 4 different stages of growth, . 30, 45, 60 and 75 days after sowing (DAS). The plants were uprooted randomly 90 DAS and the non-enzymatic and enzymatic antioxidant potentials were analysed. High salinity caused a decrease in reduced glutathione (GSH) and an enhancement in total ascorbate (AA) content and the antioxidant enzyme and ascorbate peroxidase (APX, EC ) activities. Moreover, salinity induced a significant decline in superoxide dismutase (SOD, EC ) and peroxidase (POX, EC ) activities. The changes found in catalase (CAT, EC ) activities may be of great importance in the H2O2 detoxification mechanism under oxidative stress. Key Words: Antioxidants, antioxidant enzyme, salinity, Catharanthus roseus Introduction Environmental factors influence the characters, composition, growth and development of individual plants and plant communities. When any of these environmental factors exceed the optimum tolerance of a plant, the result is stress to the plant, which in turn influences its developmental, structural, physiological and biochemical processes. Soil salinity is one of these environmental stresses (Lawlor, 2002). Every year more and more land becomes non-productive owing to salt accumulation. The major effect of salinity is the inhibition of crop growth by the reduced .