Abstract: The study deals with the changes of physiological characteristics(Photosynthetic, Exhaustion rate, Membrane permeability, Peroxidase activities, Ascorbate peroxidase actibities and root cativities) with different supplementation of PH of Heptacodium miconioides. There are 7 kinds of PH treatments (3,3.5,4,4.5,5,5.5,6,6.5,7,7.5,8,8.5)in our experiment. The results indicated that under PH 5.5 treatment,photosynthetic efficiency (Pn),respiratory intensity (Er), root activities (RA) and the activities of peroxidase (POD)、catalase(CAT)、ascorbate peroxidase (AP) of Heptacodium miconides leaves are the highest, and membrane permeability (MP) of Heptacodium miconioides leaves are the lowest. The growth of Heptacodium miconides is more favorable under PH 5.5 treatment. When PH of water medium is lower or higher than PH 5.5 ,it is disadvantageous to the growth of Heptacodium miconides.

Key words: PH, physiological characteristics, Heptacodium miconides, PH, physiological characteristics