土壤中镉、铅、锌及其相互作用对作物的影响

 通过作物盆栽模拟试验(砂壤质褐土、pH值8.2)揭示：土壤中分别施入镉(CdCl2)、铅Pb(CH3COO)2]或锌(ZnSO4)其影响表现为，植物各器官镉的含量超过对照植物的数倍至500倍。土壤镉浓度<5ppm和<10ppm分别造成某些蔬菜和水稻的污染。铅主要积累在植物根部，土壤铅污染对作物的影响较小。锌主要积累在植物叶片和根部，对水稻产生生长抑制的土壤锌浓度临界值不大于200ppm，此浓度对旱作无影响。土壤中同时施入镉和铅，植物对镉的吸收增加。而土壤中镉的增加却减少了植物体内铅的含量。土壤中由于镉、锌或铅、锌相互作用的结果，水稻对它们的吸收都有增加。在旱地土壤锌浓度的增高，降低了植物对镉、铅的吸收。镉、铅、锌同时施入土壤由于相互作用的结果，除锌之外，植物对镉、铅的吸收有明显下降。评价土壤重金属污染，不仅要看它们的含量及其存在形态，而且要分析它们之间的相互作用(促进或拮抗)特点。

The Effect of Cadmium, Lead, Zinc in Soil and Their Interaction on Crop Plants

Pot culture experiment were carried on. Cadmium (CdCl2),Lead(Pb(CH3?COO2)) and Zinc (ZnSO4) were added to sandy loam drab soil (pH8.2) respectively, it was found that the contents of cadmium in various organs of plant were several times to 500 times to the control. Under the condition of cadmium concentration at less than 5 and 10ppm in soil, some vegetables and rice were contaminated and their yields were decreased. Lead was accumulated mainly in root and the effect of the lead pollution in soil on plants was relatively low. Zinc was accumulated mainly in leave and root. When the concentration of zinc in soil was less than 200ppm, the growth of rice was inhibited. But there had no influence on dry crops at this concentration. The uptake of cadmium by plant was increased when the lead was added to the soil with 1 or 5ppm of cadmium, but the cadmium ill soil reduced the content of lead in plant. As the results of the interaction between cadmium and zinc or lead and zinc, the uptake of these elements by rice increased but the high concentration of zinc in soil of dry land reduced the uptake of lead and cadmium by plant. In order to assessment the contamination of heavy metal in soil, the concentration of heavy metal and their chemical forms in soil should be studied. To reveal the interaction between heavy metal in soil is an important aspect for assessment of soil pollution.