Abstract: The ivy (Hedera nepalensis var. sinensis) plants growing in open field or greenhouse were used as the experimentalmaterials. The changes of the semilethal temperature and the endogenous hormones in the leaves through the winter period were determined by electric conductivity and ELISA methods. The results showed that the cold resistance and the limit of endurance to the low temperature were different for the ivy plants growing under different cultivate conditions. For the p lants growing in open field, it possessed more stronger cold resistance, and its levels of endogenous hormones changed more obviously than that growing in greenhouse, such as the increase of the content of abscisic acid and the decrease of gibberellic acid. During the winter period, the changes of the contents of ABA and GA, especially the ABA /GA were associated closely with the cold resistance of ivy growing in open field.

Key words: Hedera nepalensis, Membrane injury percentage, Semilethal temperature, Endogenous hormones, Cold resistance