Abstract: The paper investigates the changes of the semilethal temperature and membrane protective system of Gardenia jasminoides Ellis leaves as temperature fell. The results show that the semilethal temperature decreased. The activity of SOD,POX and the content of Vc increased, leading to increasing of the ability of the membrane protective of scavenging free radical. In this way the level of O2 and content of MDA decreased. The decline of the semilethal temperature caused by the changes of membrane protective system was the foundation of rising the cold resistance.

Key words: Gardenia jasminoides Ellis, Semilethal temperature, Membrane protective system, Cold resistance