Using cucumber seedlings as the material, the endogenous dissociate SA in seedlings was measured using HPLC and dynamic changes of endogenous dissociate SA in cucumber seedlings was studied under lead and cadmium stress. The result was indicated the follow: 290nm detection wavelength was used for HPLC, the method had higher sensitivity and was fit for detecting SA contents of minim sample. The contents of endogenous dissociate SA in seedlings was gradually increased and POD activity was de...