Pot experiments under simulating acid rain were conducted to study the effect of Cd-Zn compound polluted on lettuce(Lactuca sativa var.angustana Irish) in purple soil.The results showed that Zn counteracted Cd to improve the yield when the concentration of Zn was low
Zn also cooperated with Cd to reduce the yield when the concentration of Zn was high.The Cd-Zn compound pollution indicated that Zn promoted the absorption of Cd by the lettuce
and Cd restrained the absorption of Cd by the lettuce
under the condition of low Zn level;Zn restrained the absorption of Cd by the lettuce
and Cd promoted the absorption of Cd by the lettuce
under the condition of high Zn level.Acid rain restrained the growth of lettuce.Biology quantity of lettuce and cumulating coefficient of Zn
Cd in lettuce increased when pH of the acid rain increased
and cumulating ability of Cd was bigger than that of Zn
which resulted in heavy metal toxicity of edible part increasing.