Sensitivity to Cd or Zn of host and symbiont of ectomycorrhizal Pinus sylvestris L. (Scots pine) seedlings.

摘要

Pinus sylvestris seedlings infected with either the ectomycorrhizal (ECM) fungus Paxillus involutus or Suillus variegatus were exposed to a range of Cd or Zn concentrations in order to investigate the relationship between the sensitivity of ECM fungi and their host plants. P. involutus ameliorated the toxicity of Cd and Zn to Scots pine with respect to root length, despite significant inhibition of ECM infection levels by Cd. Cd EC50 values (indicating 50% inhibition of ECM infection) were 3.7 and2.3μg/g Cd for P. involutus and S. variegatus, respectively. ECM infection by P. involutus also decreased Cd and Zn transport to shoots at potentially toxic concentrations and also influenced the proportion of Zn transported to the roots and shoots (with a higher proportion retained in the roots of seedlings). ECM infection increased host biomass production, but this was not affected by the presence of Cd or Zn. Root and shoot biomass production by Scots pine, in both the presence and absence of ECM fungi, was unaffected by Cd and Zn concentrations.