重金属镉、铅及其复合污染对玉米种子萌发及幼苗生长的影响

Effects of Heavy Metal Cadmium,Lead and Their Combined Pollution on Seed Germination and Seedlings Growth of Maize

通过种子发芽试验研究重金属镉(Cd)与铅(Pb)在不同浓度梯度单一和复合胁迫下对玉米种子萌发和幼苗生长的影响。结果表明:低浓度的Cd2+(0.5 mg/L)和Pb2+(10 mg/L)单一处理及其复合处理对玉米种子发芽率、发芽指数及对幼苗的芽长、根长、根数和根突起等具有一定的促进作用;高浓度的Cd2+、Pb2+单一及复合处理对种子萌发和幼苗生长具有抑制作用,且随着处理浓度的增加其抑制作用逐渐增强。高浓度Pb2+(200 mg/L)、Cd2+(100 mg/L)对玉米根长和芽长抑制率的影响最大,芽伸长抑制率与根伸长抑制率最高分别可达到58.86%和79.81%,表明重金属胁迫对根的抑制作用比芽大。在不同胁迫处理中,对玉米种子萌发指标影响最大的是镉铅复合处理,其次是镉处理,最小的是铅处理,表明镉铅复合污染对玉米种子萌发的影响表现形式为协同作用。

Responses of seed germination of maize to single and combined stress of heavy metal cadmium and lead were studied by using a hydroponic method.The main results were as follows：Low concentration of cadmium（0.5 mg/L） and lead（10.0 mg/L） and their combined stress had a great promoting influence on germination rate ,germination index and length of bud ,root length ,root number and root processus of seedling.High concentration of cadmiunl and lead and their combined stress had a great inhibitory effect on seed germination and seedling growth.As the increase of concentration of Cd^2＋,Pb^2＋and their combined stress,the inhibitive effect was gradually increased. Length of root and shoot was inhibited under high concentration Pb^2＋,Cd^2＋and their combined stress.The maximal inhibitory rate length of root and shoot reached 58.86%and 58.86%respectively.The result showed that heavy metals stress had greater influence on root than shoot.Combined stress of Pb ^2＋and Cd^2＋of greatest impact on seed germination , followed by Cd^2＋,Pb^2＋stress with minimal impact,which indicated Cd^2＋and Pb2＋combined pollution on maize was synergism action.