铅污染土壤上施用氮肥对小麦POD酶活性及铅吸收的影响

针对日益严重的土壤Pb污染，采用盆栽土培方法，比较尿素、碳酸氢铵对Pb污染土壤上有效态Pb、小麦吸收积累Pb及其体内POD酶活性的影响，为指导Pb污染土壤上施肥提供依据。结果表明，两种氮肥的施用提高了土壤有效Pb的含量，小麦根中积累的Pb显著高于茎叶。低用量氮肥（0.1~0.3g／kg）均促进了小麦生长和根对Pb的吸收，高用量氮肥（0.5~0.7g／kg）抑制了小麦的生长，但小麦茎叶中Pb的含量均降低。小麦茎叶中Pb的积累与土壤有效Pb变化无相关性。施用尿素、碳酸氢铵处理下小麦幼苗POD酶活性变化呈下降趋势。对比认为施用低浓度处理尿素更能减少铅污染土壤上在地上部的Pb积累，促进小麦的生长。

Effects of N Fertilizer on Pb Accumulation and POD Enzyme Activity of Wheat

Aim at the increasingly serious soil Pb pollution ,the effects of application of urea, NH4HCO3 on available Pb in soil, Pb absorbed by wheat and POD enzyme activity in wheat were investigated by methods of pot culture tests . The results indicated that two kinds fertilizer all improved the soil available Pb and Pb accumulation in root of wheat. The low dosage of N fertilizer (0.1~0.3g/kg)promoted biomass of wheat and the higher dosage of applying fertilizers (0.5~0.7g/kg)prohibited the growth of the wheat .Applying N fertilizers decreased the Pb accumulation in up part of wheat. While there was no obvious correlation between soil available Pb and Pb contend adsorbed by wheat . The N fertilizer can effectively alleviate negative influence of Pb on wheat seedlings and can inhibit the activity of POD enzyme in wheat. Between urea and NH4HCO3, the low dosage of urea fertilizer was better than NH4HCO3.