Study on physiological characters of cold resistance of Cycas revoluta

Physiological characters of cold resistance of C．revoluta are studied through artificially simulated cold test．The results show that penetration of protoplasm film and fettered water vary significantly with temperature．There are significant differences on the indexes of cold resistance among C．revoluta with different ages ．As the leaf age increases，the permeability of protoplasm membrane decreases，the sensitive indexes of cold damage for C．revoluta leaf decline，and the bound water and its proportion in total moisture increase，and the cold resistance rises．