Effects of Soil Water Gradient on Stress-resistant Enzyme Activities in Phragmites australis from Yellow River Delta

A simulated experiment with 5 soil water gradients was conducted to study the responses of peroxidase (POD) and the catalase (CAT) activities in Phragmites australis from Yellow River Delta on different water stresses. The results showed that: 1) the value of CAT was much higher than that of POD under all conditions; 2) a similar fluctuation change was present in both POD and CAT among the inundation levels generally, and the values of POD CAT were much higher under drought condition than those under other inundation levels, and decreased gradually with the increasing inundation levels, except CAT value has a little rise at the inundation level of 15 cm, which indicated that POD and CAT were positive to drought stress and played major role in resistance to drought in oxidative defensive systems of Phragmites australis.