Physiological responses and activities of antioxidative enzymes were investigated in pepper(Capsicum annuum) seedlings subjected to low temperature stress. The seedlings were exposed to 7℃, 11℃, or 15℃ for 4 h during the early seedling stage of pepper plants. The results showed that plant height and chlorophyll content were unaffected by the treatments. Polyphenol content in seedlings exposed to 7℃ was higher than that at 11℃ and 15℃ for 2 h. After 3 h of treatment, the flavonoid content was higher in pepper seedlings exposed to 7℃ than 11℃ and 15℃, which was slightly higher than that detected in the control. The H2O2 content increased remarkably with increasing exposure time to low temperature(i.e., 7℃) as compared to that at 11℃ and 15℃. The levels of antioxidant enzymes superoxide dismutase(SOD), catalase(CAT), ascorbate peroxidase(APX), and peroxidase(POD) fluctuated. These results provide basic information that can be utilized to maintain efficient temperature in greenhouses for sustainable growth of pepper under severe low temperature conditions.

ABSTRACT
 Introduction
 Materials and methods
  1 Plant material and treatment
  2 Measurement of plant height and chlorophyll content
  3 Measurement of total polyphenol content
  4 Measurement of total flavonoid content
  5 Measurement of H2O2
  6 Assay of antioxidant enzyme on fraction extracts
  7 Data analysis
 Results and discussion
  1 Plant growth and chlorophyll content
  2 Polyphenol content
  3 Flavonoid content
  4 H2O2 content
  5 Antioxidant enzymes
 Acknowledgement
 References

• Rayhan Ahmed Shawon(Department of Horticulture Industry, Wonkwang University, Good Agriculture Management Center, Wonkwang University)
• Dong Hyeon Kang(Department of Agricultural Engineering, National Academy of Agricultural Science, RDA)
• Chan Seok Ryu(Department of Bio Industrial Machinery Engineering, Gyeongsang National University(Institute of Agriculture and Life Science))
• Dong Eok Kim(Korea National College of Agriculture and Fisheries)
• Si Young Lee(Department of Agricultural Engineering, National Academy of Agricultural Science)
• Jong Hyang Bae(Department of Horticulture Industry, Wonkwang University, Good Agriculture Management Center, Wonkwang University)
• Yeon Ok Kim(Department of Plant Biotechnology, College of Agriculture and Life Sciences, Chonnam National University)
• Yang Gyu Ku(Department of Horticulture Industry, Wonkwang University, Good Agriculture Management Center, Wonkwang University) Corresponding author