| 摘要: |
| 【目的】探究CO2浓度升高与Cd污染耦合对刺槐幼苗根围土壤黄酮积累的影响，为重金属污染土壤的植物修复、矿区植被恢复及场地污染修复提供参考。【方法】先将供试土壤用CdSO4·8H2O处理，使土壤中Cd含量分别为0，0.45，4.5 mg/kg，放置暗处平衡5个月后，将Cd处理的土壤装盆，以刺槐幼苗为材料，采用盆栽试验，研究大气CO2浓度和高浓度CO2处理45，90，135 d后根围土壤及茎干、根系的总黄酮、槲皮素以及茎干和根系C、N、Cd含量，分析根围土壤总黄酮与茎干和根系总黄酮、C、N、Cd含量和C/N的相关性。【结果】当土壤中Cd含量为0 mg/kg时，与大气CO2浓度处理相比，高浓度CO2处理根围土壤槲皮素含量显著增加(P<0.05)；总黄酮含量在幼苗生长45 d时显著(P<0.05)增加，而90和135 d时变化不显著。当土壤中Cd含量为0.45 mg/kg时，45 d时土壤总黄酮和槲皮素含量均随CO2浓度升高而显著(P<0.05)增加， 90和135 d时土壤总黄酮含量无显著变化，而土壤槲皮素含量则显著(P<0.05)降低。当土壤中Cd含量为4.5 mg/kg时，45和90 d土壤总黄酮和槲皮素含量随CO2浓度升高而显著(P<0.05)降低，而135 d时则显著(P<0.05)升高。无论是在大气CO2浓度下还是在高浓度CO2下，当土壤中Cd含量为0~0.45 mg/kg时刺槐幼苗茎干总黄酮含量随生长时间延长而降低；45 d时幼苗根系总黄酮含量呈先降低后升高趋势，而90 d呈先升高后降低趋势，135 d时总体呈增加趋势；茎干和根系C、N、Cd含量及C/N有明显的变化，但是规律性不明显。相关性分析表明，根围土壤总黄酮含量与茎干总黄酮含量及根系C、Cd、C/N呈显著或极显著正相关，而与茎干和根系N含量呈显著或极显著负相关；根围土壤槲皮素与幼苗茎干总黄酮及根系C、槲皮素、Cd含量和C/N呈显著或极显著正相关，而与茎干和根系N呈显著或极显著负相关。【结论】茎干和根系Cd积累对CO2浓度升高的响应显著影响根围土壤总黄酮和槲皮素的积累。 |
| 关键词: 大气CO2浓度 刺槐幼苗 土壤Cd污染 根围土壤 总黄酮 槲皮素 |
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| 基金项目:国家自然科学基金面上项目（31870582，31270665） |
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| Combined effect of elevated atmospheric CO2 and Cd contamination on flavonoids accumulation in rhizosphere soil of Robinia pseudoacacia L.seedlings |
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CAO Kemeng,JIA Xia,ZHANG Chunyan,et al
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| Abstract: |
| 【Objective】This study explored the combined effect of elevated CO2 and Cd contamination on flavonoids accumulation in rhizosphere soils to provide basis for phytoremediation of heavy metal-contaminated soils,vegetation restoration in mining area and remediation of site pollution.【Method】The collected soils were treated with CdSO4·8H2O solution to obtain soils containing 0,0.45 and 4.5 mg/kg Cd,respectively.The samples were settled for 5 months before being used to plant Robinia pseudoacacia seedlings.The combined effects of ambient and elevated CO2 on total flavonoids and quercetin in rhizosphere soils,stem,and roots as well as contents of C,N and Cd in roots at 45,90,and 135 d were studied.The relationships between flavonoids in rhizosphere soils and flavonoids,C,N,C/N ratio and Cd in stem and roots were also analyzed.【Result】 Under 0 mg/kg Cd exposure,elevated CO2 improved (P<0.05) quercetin concentration in rhizosphere soils in comparison to ambient CO2.However,total flavonoids concentration reduced (P<0.05) at 45 d while no significant changes occurred at 90 and 135 d.Under 0.45 mg/kg Cd exposure,the concentrations of total flavonoids and quercetin in rhizosphere soils increased (P<0.05) with increasing CO2 at 45 d,while the changes in total flavonoids concentration were insignificant and quercetin concentration increased (P<0.05) at 90 and 135 d.Under 4.5 mg/kg Cd exposure,the concentrations of total flavonoids and quercetin in rhizosphere soils decreased (P<0.05) with increasing CO2 at 45 and 90 d but increased (P<0.05) at 135 d.Irrespective of CO2,the content of total flavonoids in stems decreased with growth time under 0-0.45 mg/kg Cd exposure.The content of total flavonoids in roots first decreased and then increased at 45 d,it first increased and then decreased at 90 d,while it mainly increased at 135 d.In addition,the changes in contents of C,N,Cd and C/N ratio in stems and roots were obvious under Cd treatments irrespective of CO2 without regularity.The Pearson correlation analysis indicated that contents of total flavonoids and quercetin in rhizosphere soils were positively related (P<0.05 or 0.01) to total flavonoids in stems and C/N ratio and Cd content in roots,and it negatively related (P<0.05 or 0.01) to N content in roots.In addition,quercetin content in rhizosphere soils was positively related (P<0.05 or 0.01) to C and quercetin in roots.【Conclusion】Cd accumulation in stems and roots and enhanced CO2 concentrations significantly influenced the accumulation of total flavonoids and quercetin in rhizosphere soils. |
| Key words: elevated atmospheric CO2 Robinia pseudoacacia seedling Cd-contaminated soils rhizosphere soils total flavonoids quercetin |
