小麦幼苗经镉胁迫后 ,随着镉浓度的增高 ,叶片和根系中的膜脂过氧化产物丙二醛( MDA)的含量和过氧物酶 ( POD)活性明显升高 ,超氧物歧化酶 ( SOD)活性也有所提高。叶片中 MDA积累量和 SOD活性都高于根 ,而 POD活性则是根高于叶片。随幼苗生长时间延长 ,叶片和根中的 MDA积累量增加 ,而 SOD活性却降低。 After cadmium stress, the contents of malondialdehyde (MDA) and peroxidase (POD) of membrane lipid peroxidation in leaves and roots were significantly increased with the increase of cadmium concentration. The activities of superoxide dismutase (SOD) activity has also increased. MDA accumulation and SOD activity in leaves were higher than roots, while POD activity was higher than leaves. With the prolongation of seedling growth, MDA accumulation in leaves and roots increased while SOD activity decreased.