FIGURE 3.

Effects of CdCl₂ on steady Ca²⁺ fluxes in Populus × canescens roots and Paxillus involutus strains MAJ and NAU. P. involutus isolates, ectomycorrhizal (MAJ and NAU) and non-mycorrhizal (NM) P. × canescens plants were subjected to short-term (ST, 24 h) and long-term (LT, 7 days) exposure to 50 μM CdCl₂, respectively. Control roots and axenic mycelia were well fertilized but treated without CdCl₂. Ca²⁺ fluxes in poplar roots were measured along root axis, 100–2,300 μm from the apex, at intervals of 200–300 μm. Ca²⁺ fluxes of P. involutus isolates MAJ and NAU were measured along the surface of pelleted hyphae over a recording period of 30 min. Inserted sections show the Ca²⁺ fluxes in P. involutus isolates after short-term (ST, 24 h) or long-term (LT, 7 days) CdCl₂ treatment. Each point is the mean of 4–5 individual plants or axenic EM cultures (pelleted hyphae), and bars represent the standard error of the mean. Asterisks denote significant difference at P < 0.05 between treatments.