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[目的]探讨柳树对单一或复合重金属的耐性大小,为木本植物修复重金属污染土壤提供理论依据。[方法]采用根生长法研究重金属Cu2+、Pb2+、Zn2+及3者混合液对柳树枝条不定根生长的影响。调查项目包括柳树枝条不定根的数目及长度,并由此计算生根率、抑制率和耐性指数。[结果]不同浓度的重金属溶液对柳树枝条不定根的生长存在显著影响。当Cu2+浓度高于15mg/L、混合溶液浓度高于20mg/L、Zn2+浓度高于30mg/L时,柳树枝条均无不定根生成;溶液浓度达到40mg/L时,只有Pb2+处理组能长出不定根;随着溶液浓度的升高,柳树枝条不定根的数目逐渐下降;浓度为5mg/L的Zn2+处理组柳树枝条不定根数目最多。其他浓度中,Pb2+处理组不定根数目最多、根长及平均根长最长、生根率最高。[结论]柳树枝条对Pb2+的耐受性最强,对Cu2+的耐受性最弱。柳树对3种重金属及3者混合液的耐受性大小依次为Pb2+>Zn2+>Cu2++Pb2++Zn2+>Cu2+。
[Objective] The research aimed to study the tolerance of willow to single or complex heavy metals and provide theoretical basis for woody plant to remediate heavy metal contaminated soil. [Method] The effects of Cu2 +, Pb2 +, Zn2 + and their mixture on the adventitious root growth of willow branches were studied by root growth method. The investigation items included the number and length of adventitious roots of willow twigs, and the rooting rate, inhibition rate and tolerance index were calculated from the results. [Result] Different concentrations of heavy metal solution had significant effect on the adventitious root growth of willow branches. When the concentration of Cu2 + was higher than 15mg / L, the concentration of mixed solution was higher than 20mg / L and the concentration of Zn2 + was higher than 30mg / L, no adventitious roots were formed in the branches of willow. When the solution concentration reached 40mg / L, The number of adventitious roots in willow branches decreased gradually with the increase of solution concentration. The adventitious roots of willow branches with Zn2 + concentration of 5 mg / L had the highest number of adventitious roots. In other concentrations, Pb2 + treatment group had the largest number of adventitious roots, the longest root length and the longest root length, and the highest rooting rate. [Conclusion] Willow twigs had the strongest tolerance to Pb2 + and the weaker to Cu2 +. The tolerability of willow to three kinds of heavy metals and three mixed solutions was Pb2 +> Zn2 +> Cu2 + + Pb2 + + Zn2 +> Cu2 +.