Cr(Ⅵ)、Pb(Ⅱ)胁迫对双穗雀稗生长发育的影响

Effects of Chromium and Lead Stress on Growth and Development of Paspalum distichum L.

以消落带适生植物双穗雀稗(Paspalum distichum L.)为实验材料,通过水培试验,研究了外源重金属Cr(Ⅵ)、Pb(Ⅱ)单一及复合处理时对双穗雀稗生长及Cr、Pb在双穗雀稗中的迁移富集情况。结果表明:1低浓度Cr(≤80μmol/L)、Pb(≤400μmol/L)对双穗雀稗生长有促进作用,根系耐性指数大于1,双穗雀稗叶片的叶绿素质量分数明显上升;而随着Cr、Pb浓度的增加,双穗雀稗的生长显现出中毒现象,叶尖发黄且叶片叶绿素质量分数下降,根部变成黑褐色,根系耐性指数小于1;2双穗雀稗主要通过地下部和地上部迁移富集Cr和Pb,随着处理浓度的增加,迁移富集量逐渐增大,Cr(Ⅵ)、Pb(Ⅱ)共存对Cr、Pb迁移富集有协同作用。3Cr、Pb在双穗雀稗中的转运系数小于1,不是铬、铅的超累积植物,但能明显降低水体中的Cr、Pb,因而双穗雀稗既是消落带植被重建的优良物种,也能较好修复水体中的铬、铅污染。

The hydro-fluctuation Belt Plants（ Paspalum distichum L.） of Three Gorges Reservoir was taken as the key object in this study.The enrichment and transportation behavior of Cr（ Ⅵ） and Pb（ Ⅱ） in Paspalum distichum L. were investigated by using the hydroponic experiment,and the effect of combined contamination of Cr（ Ⅵ） —Pb（ Ⅱ） on the growth of Paspalum distichum L. was also studied in detail.The results showed that under low concentration of Chromium（ ≤80 μmol / L） and lead（ ≤400 μmol / L） stress,the growth of Paspalum distichum could be improved,the root tolerance index was greater than 1,their chlorophylls in leaves could increase; However,with the increase of Cr and Pb,the effect on the growth of Paspalum distichum had been exerted. The chlorophylls content of Paspalum distichum in leaves decreased,The root tolerance index was less than 1. Paspalum distichum primarily through roots,stems enrichment of heavy metal ions,with the increase of concentration enrichment increasing migration. Cr（ Ⅵ） and Pb（ Ⅱ） in P. distichum migration exhibited synergistic effects. It suggested that P. distichum had the ability to repair Heavy metal Cr and Pb pollutions. Therefore,the Paspalum distichum was the good plants for the river water ecosystem restoration.