Effects of cadmium stress on seed germination and seedling growth of Elymus dahuricus infected with the Neotyphodium endophyte.

Various cadmium (Cd) concentrations (0, 50, 100, 200 and 300 μmol L(-1)) affected Elymus dahuricus seed germination, seedling growth, antioxidative enzymes activities (AEA), and amounts of malondialdehyde (MDA) and proline present. These influences were determined for separate E. dahuricus cohorts known to be either infected (E+) or non-infected (E-) by a Neotyphodium endophyte. Under high Cd concentrations (100, 200 and 300 μmol L(-1)), E+ specimens showed a significantly (P<0.05) higher germination rate and index, as well as higher values for shoot length, root length and dry biomass. However, the germination rate and index, root length and dry weight did not show a significant (P<0.05) difference under the low Cd concentrations (0 and 50 μmol L(-1)). AEA and proline content increased, as did MDA content, in the E+ (vs. E-) specimens under high Cd concentrations. There was no significant (P>0.05) difference under low Cd concentrations. Endophyte infection was concluded to be of benefit to E. dahuricus exposed to high Cd concentrations.