蜈蚣草对Pb、Zn复合污染的响应

为探明蜈蚣草修复重金属复合污染土壤的能力,本实验利用水培实验研究Pb、Zn交互作用下蜈蚣草对Pb、Zn积累变化以及蜈蚣草对Pb、Zn的解毒机理.实验结果显示,在Pb、Zn复合污染情况下,重金属Zn在0—10 mg.L-1下可促进蜈蚣草根、茎对Pb的富集能力,降低蜈蚣草对Pb的转运能力;而Pb则促进蜈蚣草对Zn的转运系数,提高蜈蚣草茎、叶对Zn的富集能力,并呈现出蜈蚣草对Pb的富集能力大于对Zn的富集能力.实验结果进一步显示,随着重金属复合暴露浓度增加,蜈蚣草叶绿素含量先上升后下降,丙二醛含量先下降后上升,淀粉、蔗糖、O2-含量则逐渐上升.这说明淀粉、蔗糖、O2-.等具有一定的解毒作用,能增强植物对重金属的抗性.实验结果还显示,蜈蚣草对Pb、Zn具有较强的耐性和富集能力,可利用蜈蚣草修复Pb污染土壤以及低Zn浓度的Pb-Zn复合污染土壤.

Study on response of Pteris vittata to Pb and Zn combined pollution

Combined heavy metal pollution is one of main soil pollutions.In order to investigate the ability of Pteris vittata in restoring soils with combined heavy metal pollution,water cultured experiment was utilized to study the accumulation of Pb and Zn in Pteris vittata and the detoxification mechanism of Pteris vittata to heavy metals under the combined Pb and Zn exposure.The experimental results show that under Pb and Zn combined exposure,Zn improved the enrichment ability of Pteris vittata roots and stems for Pb,and reduced its translocation ability for Pb as well.Pb also improved the translocation ability of the plant for Zn and its enrichment ability.The enrichmant ability of Pteris vittata for Pb was stronger than for Zn.With increasing heavy metal concentrations,chlorophyll content incrensed first and then decreased.Malondialdehyde(MDA) content decreaed first and then increasd.Starch,sucrose and superoxide radical(O-2 ·) contents all increased gradually.These results show that starch,sucrose and superoxide radical(O-2 ·) had certain detoxification function,and strengthened resistance of the plants to heavy metals.These results also show that Pteris vittata has tolerance and enrichment ability to Pb and Zn,and Pteris vittata can be used to restore Pb polluted soil and Pb-Zn combined polluted soil under low Zn concentrations.