Effect of Temperature and γ-Radiation on Antioxidant Defense System in Suspension Cell Culture of Carnation (Dianthus caryophyllus)

This study was conducted to investigate the response of carnation (Dianthus caryophyllus cv. Oldrush) suspension cell to high temperature and gamma (γ) rays. Carnation cells were exposed to different doses of γ-radiation (0-6000 rad). Both radiated and non-radiated cells grown at 25℃ were then exposed to the temperature treatments of 35℃ (continuous exposure for 2 weeks), 45℃ (exposure 5 h/day for 2 weeks), and 55℃ (exposure for 1 h). The activities of reactive oxygen species scavenging enzymes (superoxide dismutase, catalase, and peroxidase), cell viability, and proline content were determined. The results showed that γ-radiation treatments protected carnation cells against the progressive oxidative damage by high temperature stress. The continuous exposure to heat stress could be more favorable to obtain tolerant cells. This tolerance has been indicated by increased accumulation of free proline and antioxidative activity, which are considered as a protective physiological response to high temperature stress.