重金属污染土壤修复中的根际效应研究进展

Research progress of rhizosphere effect in the remediation of heavy metal contaminated soil

由根际分泌物介导的根际效应表现为根际土壤中微生物种类和活性、土壤理化性质(如酶、pH、有机质等)显著不同于非根际土壤。根际效应受土壤类型、植物种类等影响较大,在农业生产、林业防护等领域被广泛研究,并被投入到实际应用中。近年来,根际效应在土壤修复领域的研究取得了一定进展,但对其修复机制、影响因素等尚缺乏系统性的认识。综述了受重金属污染土壤中根际效应的修复机制、影响因素,并提出加强修复效果的措施,以期利用根际效应提高土壤生物修复效率。根际效应驱动根际土壤与非根际土壤中重金属的形态和分布差异显著,受土壤类型、植物功能性状、重金属性质等因素影响,土壤改良、接种外源微生物等措施可强化植物根际对重金属污染土壤的修复效果。然而目前相关研究时间较短、规模较小,忽略了多年生植物不同生长阶段的根际效应对重金属修复效果的影响,植物生长发育周期长导致筛选特异性修复植物也存在一定的挑战。随着根际效应在土壤修复领域研究的深入,建议展开更系统、全面、长期的指标监测研究,从而明确影响根际效应修复重金属的主次因素,同时筛选出针对不同重金属污染土壤的特异性修复植物,以便于建立土壤生物修复的植物资源库。

The rhizosphere effect mediated by rhizosphere exudates shows that the species and activities of microorganisms,and soil physicochemical properties such as enzymes,pH and organic matter in rhizosphere soil are significantly different from those in non-rhizosphere soil.Rhizosphere effect is greatly affected by soil types and plant species,etc.,and has been widely studied and used in agricultural production and forestry protection.In recent years,some progress had been made in the research of rhizosphere effect on soil remediation,but systematic understanding of its remediation mechanism and influencing factors still needed to be further improved.In this study,the remediation mechanism and influencing factors of rhizosphere effect in heavy metal contaminated soil were reviewed and analyzed,and the measures to strengthen the remediation effect were proposed to improve the soil bioremediation efficiency by rhizosphere effect.The review indicated that the rhizosphere effects drove the significant differences in the form and distribution of heavy metals between the rhizosphere and non-rhizosphere soils.Affected by soil types,plant functional traits,heavy metal properties and other factors,soil improvement and inoculation of exogenous microorganisms could enhance the remediation effect of plant rhizosphere on heavy metals contaminated soil.However,current studies were in short term and small scale,and had neglected the rhizosphere effects at different growth stages of perennial plants on heavy metal remediation,and the long cycle of plant growth and development set a challenge for screening of specific remediation plants.With the deeper study of rhizosphere effect in the field of soil remediation,it was necessary to carry out more systematic,comprehensive and long-term index monitoring researches to identify the primary and secondary factors affecting the restoration of heavy metals by rhizosphere effect.At the same time,specific remediation plants of different heavy metal contaminated soil types were needed to be selected to facilitate the establishment of soil bioremediation plant resource bank.