Abstract: To understand the ecophysiological adaptation of Lilium“Oriental Hybrids”which was grown for the commercial bulb, the gas exchange, leaf N and chlorophyll content of three varieties were investigated in the middle of Yunnan province. Among three varieties, light saturated photosynthetic rate at ambient CO₂ (A_max ) of“Siberia”was the highest, while“Siberia” (was the lowest. The difference in A_max was related to the carboxylation efficiency (CE), leaf mass per unit area and leaf N content per mass, which indicated that their photosynthetic capacity was influenced by the activity and/or the number of Rubisco. Three varieties had lower photosynthetic saturation point and photosynthetic compensation point, but their photosynthetic rate not decreased up to 2 000μmol m^{- 2} s ^{- 1}. This indicated that three varieties had broad adaptability to light intensity. There were significant differences in photosynthetic optimum temperature among three varieties. However, the variety“Siberia”had the highest photosynthetic optimum temperature ( 25.5℃- 34.9℃ ), and it was suitable to grow in the warm area. “Sorbonne”had the lowest photosynthetic optimum temperature ( 19.3℃- 25.6℃ ), and it can be grown in the cool area.“Tiber”could maintain high photosynthetic rate at a wide range of temperature, so it was more suitable for the climate in the middle of Yunnan province.

Key words: East lily ( Lilium“Oriental Hybrids”)