铁冬青幼苗对污染土壤中铅、镉的耐受、吸收和累积

Tolerance,absorption and accumulation of Ilex rotunda seedlings to lead and cadmium in polluted soil

【目的】研究铁冬青Ilex rotunda在铅(Pb)、镉(Cd)污染土壤上生长的耐受性及其对Pb、Cd的吸收累积能力,为Pb、Cd污染土壤的植物修复提供理论依据。【方法】通过盆栽试验探究单一Pb污染(500、1000和1500 mg·kg^(−1))和单一Cd污染(10、25和50 mg·kg^(−1))对铁冬青幼苗生长、根系形态、养分及Pb或Cd吸收累积的影响。【结果】与对照(无污染土壤)相比,500 mg·kg^(−1)的Pb处理显著增加铁冬青根生物量和根表面积,500和1000 mg·kg^(−1)的Pb处理均显著增加地径和质量指数;1500 mg·kg^(−1)的Pb处理显著降低铁冬青生物量、质量指数和全株N累积量,抑制根系生长,但显著提高根、地上部P含量和地上部K含量;Pb污染处理均显著增加铁冬青全株Pb含量以及根、全株Pb累积量,1500 mg·kg^(−1)的Pb处理的铁冬青各部位及全株的Pb含量和累积量最大。与对照相比,单一Cd污染对铁冬青生长、根系形态、养分累积量均无显著影响,但显著提高地上部K含量;各Cd污染处理均显著增加铁冬青各部位和全株的Cd含量及累积量,根Cd含量随着Cd污染程度增加而显著增加,在50 mg·kg^(−1)的Cd处理时达到最大值(6.40 mg·kg^(−1))。铁冬青根Pb含量及累积量均显著高于地上部;根Cd含量在不同Cd污染条件下均显著高于地上部,根Cd累积量在50 mg·kg^(−1)的Cd处理时显著高于地上部。【结论】铁冬青对单一Pb、Cd污染具有较好的耐受性,对Pb、Cd有较强的吸收累积能力,可作为Pb、Cd污染土壤修复的备选树种。

【Objective】This study was aimed to investigate the tolerance of Ilex rotunda,absorptions and accumulations of lead(Pb)and cadmium(Cd)in Pb or Cd polluted soil,and provide a theoretical basis for phytoremediation of Pb or Cd contaminated soil.【Method】A pot experiment was conducted to evaluate the effects of single Pb pollution(500,1000 and 1500 mg·kg^(−1))and single Cd pollution(10,25 and 50 mg·kg^(−1)on growth,root morphology,nutrients and Pb or Cd absorption and accumulation of I.rotunda seedlings.【Result】Compared with the control(non-polluted soil),500 mg·kg^(−1)Pb treatment significantly increased the root biomass and root surface area of I.rotunda,and both 500 and 1000 mg·kg^(−1)Pb treatments significantly increased shoot diameter and quality index.1500 mg·kg^(−1)Pb treatment significantly reduced the biomass,quality index,and total nitrogen(N)accumulation of I.rotunda and inhibited root growth,but significantly increased phosphorus(P)contents in root and shoot as well as potassium(K)content in shoot.All Pb addition treatments showed significantly higher total Pb contents and accumulations than those of the control treatment,and 1500 mg·kg^(−1)Pb treatment had the highest Pb contents and accumulations in root,shoot and total plant.Compared with the control,Cd treatments had no significant effect on growth,root morphology and nutrient accumulation of I.rotunda,but significantly increased K content in shoot.All Cd treatments significantly increased Cd contents and accumulations in root,shoot and total plant.Root Cd content increased significantly with the increase of Cd concentration,while 50 mg·kg^(−1)Cd treatment had the highest root Cd content of 6.40 mg·kg^(−1).The content and accumulation of Pb in root were significantly higher than those in shoot.Cd content in root was also significantly higher than that in shoot.Cd accumulation in root was significantly higher than that in shoot under 50 mg·kg^(−1)Cd treatment.【Conclusion】I.rotunda is well adapted to single Pb or Cd pollution in soil,and has a strong ability to absorb and accumulate Pb or Cd.I.rotunda can be used as a candidate tree for remediation of Pb or Cd polluted soil.