Abstract: Investigated the adaptation of Gardenia jasminoides Ellis leaves to natural temperature reduction. The results showed that with temperature decreased, the semilethal temperature(LT50) decreased increasingly. The content of osmoregulation substance such as soluble suger, soluble protein increased to the different degree, while the content of starch decreased. The content of endogenous hormone such as ABA rose continuously and negatively correlated to LT50(R=－0.967 3). On the contrary, the content of GA reduced, which the content of GA was positively correlated to LT50(R=0.812 5). In summary, the adaptive changes of these substance including osmoregulation substance and endogenetic hormones of G. jasminoides Ellis leaves led to the reduction of LT50, thus make G. jasminoides Ellis suit the low temperature condition cuitivated and pass the winter safely.

Key words: Gardenia jasminoides Ellis, semilethal temperature, osmoregulation substance