单一及复合污染下铅铜在玉米幼苗体内积累与迁移的动态变化

Dynamics of Accumulation and Distribution of Cu,Pb in Zea mays L.Seedlings Under Single or Combined Pollution of Cu and Pb

采用光照培养箱培养及原子吸收分光光度法,研究了不同浓度(10～100mg·L-1)Cu2+、Pb2+单一及复合污染后玉米幼苗体内各器官中积累与迁移的动态变化规律。结果表明,在单一污染条件下,Cu2+、Pb2+在玉米体内的积累量与重金属处理浓度和处理时间呈正相关,分布顺序为根>茎>叶,积累量为Pb2+>Cu2+,根茎间迁移率随着处理浓度增高逐渐减小,茎叶间迁移率变化规律为先减小后增大;复合污染后,随着处理浓度和处理时间的增加,Cu2+、Pb2+在玉米体内的积累量逐渐增大,其中(100+100)mg·L-1浓度下30d处理时积累量达到最大值,Cu2+、Pb2+在玉米各器官中的分布规律为根>茎>叶,积累能力为Pb2+>Cu2+,根茎间的迁移率表现为在10～20d时随浓度增高逐渐上升,30d时逐渐下降,而茎叶间的迁移率则表现为随处理浓度的增加先升高后降低。Cu2+、Pb2+复合污染后玉米体内Cu2+、Pb2+的含量均大于单一处理,Cu2+、Pb2+复合处理具有协同效应。实验结果也证明玉米是一种易富集Cu2+、Pb2+的作物。

The elements Cu and Pb are two important heavy metal pollutants. Pb2＋ is a non-essential element which has an obvious toxic ef- fect on cell uhrastrueture, seed vitality, growth, development and nutrient metabolism with its accumulation in crops. Cu2＋ is an essential ele- ment, which may promote growth and development with an optimum quantity,but its excessiveness ean have some obvious biological toxicity. The accumulation and distribution of Cu2＋ and Pb2＋ in Zea mays seedlings under different concentrations（ 10, 50, 100 mg.L-1）were studied in this experiment using atomic absorption spectrometry after the treatment of 10, 20 and 30 d. The result showed that under single or combined pollution of Cu2＋ and Pb2＋, the content of heavy metals in Z. mays seedlings enhances with the increasing of treatment concentration and treatment duration, and the accumulation amount in roots of Z. mays seedlings was the largest at 30 d with 100 mg. L-1 of heavy metals .The content of Cu2＋ or Pb2＋ in different organs of Z. mays seedlings was characterized by roots〉stems〉leaves, and the accumulation amount in each organ was PbZ〉Cu2＋ .The accumulation amount of Cu2＋, Pb2＋ in Z. mays Seedlings under combined pollution was much more than that under single pollution, and it indicated that compared with the single pollution, the combined pollution by Cu2＋ and Pb2＋ displays some kind of syn- ergistic effect. Meanwhile, the mobility of Cu2＋, Pb2＋ was basically dependent on Cu2＋, Pb2＋ concentration and treatment duration. The mobility between roots and stems under Cu2＋ or Pb2＋ single pollution increased with heavy metal concentration, but the mobility between stems and leaves firstly declined, and then increased with increasing of Cu2＋ or Pb2＋ concentration. The mobility between stems and leaves under com- bined pollution was larger than that under single pollution.