Pb、Cd单一及复合污染对小麦种子萌发和幼苗毒害作用

采用砂基培养方法,研究重金属Pb、Cd单一及其复合污染对小麦种子萌发和幼苗生长及生理生化特性的影响。结果表明：当Pb离子浓度≤15mg/L,Cd离子浓度≤5mg/L,二者复合离子浓度≤10mg/L时,对小麦种子的萌发率、芽及幼根生长、叶绿素含量、CAT、POD酶活性都有促进作用;当超过此浓度时则表现为抑制作用。从根冠比可看出Pb、Cd对小麦根的影响大于对芽生长的影响,植物根对重金属污染的生态毒性最为敏感。Cd对小麦的毒害作用强于Pb;Cd、Pb复合污染对小麦的根系活力、叶绿素含量的影响比较复杂,复合浓度≤10mg/L时略弱于Cd单一污染;随着浓度进一步升高,会强于Cd单一污染,始终强于Pb单一污染。

Heavy Metal Pb,Cd Single and Combination Pollution on Seed Germination and Seedling Toxic Action

Effects of single and the compound pollution of heavy metal Pb,Cd on seed germination,seedling growth and physiological and biochemical characteristics of wheat were examined in a granulated substance experiment.The results indicated：When Pb~（2＋） concentration was lower than 15mg/L,Cd~（2＋） concentration was lower than 5mg/L and the two complex ion density was lower than 10mg/L,they had the positive action on the wheat seed germination rate,the bud and the radicle growth,the chlorophyll content,CAT and POD activity.The root of wheat was greatly influenced stronger than that of bud from the root cap rate by Pb,Cd,the roots were the most senstive to ecological toxicity of heavy metal.Cd to wheat toxicity was more serious than Pb,the compound pollution of Cd and Pb was complex for effects of roots activity,chlorophyll content of wheat,compound density lower 10mg/L was slightly weaker than Cd sole pollution,with the density promotion,it would be higher than Cd sole pollution,but it was always stronger than Cd single pollution.