Abstract: Cadmium (Cd) pollution in soil is a global problem. Mycorrhizalplant symbiosis can effectively repair Cd-contaminated soil. To understand the cadmium tolerance mechanism of Arundos donax inoculated with dark septate endophyte (DSE), a pot experiment was carried out to investigate the effects of DSE inoculation on the growth, photosynthesis and mineral nutrition of A. donax under Cd stress. The results showed that inoculation of DSE significantly improved the growth ofA. donax under Cd stress. Compared with CK, plant height, number of tillers, and aboveground biomass were increased by 12.97%-20.08%, 7.69%-45.45%, and 18.97%-28.35%, respectively. In addition, the apparent quantum rate and dark respiration rate were increased by 17.50%-46.77% and 7.81%-52.42%. The concentrations of total N, P, and K in roots were increased by 12.99%-40.60%, 18.07%-38.18%, and 23.00%-48.67%, respectively. The Cd concentrations in shoots and roots were significantly increased by 62.11%-91.87% and 8.13%-71.01%, respectively. The effects of DSE on A. donax under Cd stress varied with strains inoculated. The Cd translocation factor of LZ01LZ03 treatments were all greater than 1. The LZ01A. donax symbiont was the best combination under the experimental conditions. Cd stress and DSE had a significant interaction effect on the growth, photosynthesis and nutrient concentration of A. donax, with significant correlations among these three traits. The results indicated that inoculation with DSE can promote the growth and photosynthesis of A. donax, increase mineral nutrition, and enhance Cd absorption and transportation of A. donax under Cd stress. DSEA. donax symbiont is relatively resistant to Cd stress, with potential application prospect to Cd contaminated soil remediation.

Key words: dark septate endophyte, Arundo donax, cadmium, pollution, soil remediation.