Abstract:The effect of Zn on tall fescue (Festuca arundinacea Schreb.) infected with or free from Neotyphodium coenophialum was studied by addition of ZnSO4 to the nutrient solution to analyse the effect of endophyte infection. Compared with the endophyte\|free tall fescue, endophyte infection did not improve the total biomass of tall fescue, but the symbiotic plants showed higher values of tiller number and cumulative leaf length. The presence of the fungus in the plant led to a limitation of the total Zn concentration and modified the pattern by decreasing the Zn concentration in leaves and increasing the Zn concentration in sheaths. Under high Zn stress, the alleviation of negative effect on net photosynthetic rate was not shown, but endophyte infection increased photosystem II (PSII) activities. In conclusion, endophyte infection had a beneficial effect of Zn stress on the host tall fescue.