模拟酸雨作用下紫色土锌镉复合污染对莴笋的影响

通过盆栽实验研究了酸雨影响下紫色土Zn-Cd复合污染对莴笋的影响。结果表明：酸雨影响下，Zn为低水平时，Zn-Cd复合污染对莴笋表现为拮抗增产；Zn为高水平时，复合污染对莴笋表现为协同减产。重金属累积量在Zn-Cd复合污染时表现为Cd对Zn的作用和Zn对Cd的作用恰好相反：在Zn为低浓度时，Zn促进了莴笋对Cd的吸收，Cd抑制了莴笋对Zn的吸收；在Zn为高浓度时，Zn抑制了莴笋对Cd的吸收，Cd促进了莴笋对Zn的吸收。酸雨对莴笋的生长起抑制作用，莴笋生物量随着酸雨pH值的升高而增加，而莴笋地上部分重金属的富集能力也随之增强．并且Cd的富集能力明显大于Zn，莴笋可食部分毒性也随之增大。

Effect of Compound Pollution of Zn-Cd in Purple Soil on Lettuce under Simulating Acid Rain

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.