Materials and Methods
Three-year-old ‘Niitaka’ pears cultivated in the rhizotron with controlled temperature and CO2 concentration at the National Institute of Horticultural & Herbal Science in Suwon, Korea were used. CO2 concentration was controlled using an infrared gas analyzer (ZRH model, Fuji Electric Co., Tokyo, Japan), while temperature was controlled by a distributed control system (POREX 6800, POSCON Co., Pohang, Korea) based on real time climate information. As a factorial experiment, the treatments included 1) ambient temperature and 390 LL-1 CO2 (control group), 2) ambient temperature + 4and 390 LL-1 CO2 (elevated temperature group), 3) ambient temperature and 700 LL-1 CO2 (elevated CO2 group), and 4) ambient temperature + 4and 700 L L-1 CO2 (elevated climate group).