Abstract: To understand the eco-physiological adaptability of Davidia involucrata, th e peroxidase (POD) activity and MDA content of D. involucrata leaves of dif ferent age class and at different leaf layer and leaf position were analyzed by the method of colorimetry. The results showed that the D. involucrata leaves of different age class but at the same growth phase had different POD activity and MDA content. With increasing leaf position, the POD activity of the leaves o f same age class and at the same leaf layer had a decrease after an initial incr ease, while the MDA content was increasing. The POD activity and MDA content of the leaves at same leaf position but at different leaf layer and those at differ ent leaf position but at same leaf layer also varied. Growth phase had greater e ffects on the leaf POD activity and MDA content. With the growth and senescence of leaf, the POD activity and MDA content of the leaves of same age class and at same leaf position increased gradually. The POD activity and MDA content of D . involucrata leaves were affected by both biological and non-biological fact ors, and varied with leaf age class, leaf position, and leaf layer.

Key words: Plantation, Forest stock, Western Liaoning area