Chinese Bulletin of Botany ›› 2018, Vol. 53 ›› Issue (1): 72-81.DOI: 10.11983/CBB17004

• EXPERIMENTAL COMMUNICATIONS • Previous Articles     Next Articles

Responses of the Antioxidant Defense System of Osmanthus fragrans cv. ‘Tian Xiang TaiGe’ to Drought, Heat and the Synergistic Stress

Xinlu Xu, Dandan Li, Yuandan Ma*(), Jianyun Zhai, Jianfei Sun, Yan Gao, Rumin Zhang   

  1. School of Forestry and Biotechnology, Zhejiang A&F University, Lin’an 311300, China
  • Received:2017-01-06 Accepted:2017-05-04 Online:2018-01-01 Published:2018-08-10
  • Contact: Yuandan Ma

Abstract: In this study, we explored the solo effect of drought stress (control, light, moderate and heavy), heat stress (control 28°C, heat 40°C) and their dual stresses on the antioxidant defense system of Osmanthus fragrans cv. ‘Tian Xiang TaiGe’. The experiment data showed that after drought treatment, reactive oxygen species (ROS) accumulated gradually and membrane lipid peroxidation increased; the activity of antioxidant enzymes increased significantly under light and moderate drought stress. Ascorbic acid (AsA) and its reducing power (AsA/DHA) decreased significantly under heavy drought stress, whereas glutathione (GSH) and its reducing power (GSH/GSSG) as well as the activity of enzymes related to ascorbate glutathione cycle (AsA-GSH cycle) showed a trend of first increasing and then decreasing, with the peak reached after moderate drought stress. Unlike drought stress, ROS accumulation, antioxidant enzyme activity, antioxidant content and AsA-GSH cycle efficiency all improved significantly with heat stress. Furthermore, we found that the dual stresses injured the cultivar more severely than either stress alone. ROS level increased slowly via antioxidant enzyme activity, and the AsA-GSH cycle efficiency was enhanced at first and then decreased significantly with increasing dual stresses, especially after severe stress, and was unable to maintain oxidation reduction equilibrium. Under drought and heat stress, the cultivar quickly activated the antioxidant defense system to eliminate ROS, which improved the reducing power of the organism to reduce the environmental damage.

Key words: Osmanthus fragrans var. semperflorens, drought, heat, reactive oxygen species, antioxidant enzyme, ascorbate glutathione cycle