丛枝菌根真菌影响桉树吸收和积累土壤中重金属元素的研究

There are large areas of soil polluted by heavy metals, and also large areas of Eucalyptus forest in Guangxi province. However, the studies in literatures are limited to the absorption and accumulation of single heavy metal by Eucalyptus inoculated with arbuscular mycorrhizal fungi (AMF) in pot experiments. So the essential scientific question of the contribution of AMF to the absorption and accumulation of heavy metals (Cd, Zn and/or Pb) in soil by Eucalyptus is proposed. Under the conditions different from literatures such as pot experiments (simulated pollution soil, real pollution soil) and field experiments, the project will study the absorption and accumulation of heavy metals by Eucalyptus inoculated by AMF. The root infection ratio of Eucalyptus, the biomass of Eucalyptus root and shoot, the amounts of heavy metals Cd, Zn and Pb in Eucalyptus root and shoot, and the subcellular distribution of heavy metals in Eucalyptus would be determined. The contribution of AMF to the absorption and accumulation of heavy metals by Eucalyptus and the detoxification mechanisms of Eucalyptus to heavy metals would also be discussed. The results will help to the application potential of Eucalyptus, the cultivation of Eucalyptus forest, the safety of local soil environment, and the reclaim of mine area.

针对广西大面积土壤被重金属严重污染和广泛种植人工桉树林的实际情况，以及文献研究局限于丛枝菌根真菌影响桉树吸收和积累模拟污染土壤中单一重金属元素的不足之处，提出了本项目的基本科学问题：丛枝菌根真菌对桉树吸收和积累重金属元素的作用。项目针对有广西特色的有色金属污染状况，采用模拟污染土壤和实际污染土壤盆栽实验及大田实验的方法，研究丛枝菌根真菌和重金属元素Cd、Zn和Pb作用下，桉树幼苗的真菌侵染率、根和地上部分的生物量及重金属含量的变化，明确丛枝菌根真菌对桉树幼苗吸收和积累多种重金属元素的影响；同时研究桉树幼苗根、茎和叶亚细胞中重金属元素Cd、Zn和Pb分布的变化，以及丛枝菌根真菌对此的影响，揭示丛枝菌根真菌作用下桉树对重金属元素的解毒机理，阐述盆栽和大田实验条件下丛枝菌根真菌对桉树吸收和积累重金属元素的作用，发掘桉树的应用潜力，为广西人工桉树林培育、区域土壤环境安全和矿区复垦等提供理论依据。

针对广西重金属污染现状，采用模拟污染土壤盆栽、实际污染土壤盆栽和大田实验的方法，研究了丛枝菌根真菌（AMF）对桉树吸收和积累重金属元素Cd、Zn和Pb的作用，同时研究了重金属在桉树幼苗根、茎和叶中的亚细胞中分布，以及AMF对重金属亚细胞分布的影响，揭示AMF作用下桉树对重金属元素的解毒机理。实验结果表明：桉树根部吸收的重金属主要分布于细胞壁组分中；重度污染时，重金属在可溶组分中的比例增加；接种AMF可增强细胞壁的固持作用及可溶组分的区隔化作用。重度污染时，桉树限制对重金属的吸收、根部的滞留作用、细胞壁的固持作用及可溶组分的区隔化作用是桉树耐受Cd、Pb和Zn的重要机制。AMF的接种一定程度上增强了上述一种或几种耐受作用。项目的研究结果能发掘桉树的应用潜力，为广西人工桉树林培育、区域土壤环境安全和矿区复垦等提供理论依据。