Germination and seedling anti-oxidative enzymes of endophyte-infected populations of Elymus dahuricus under osmotic stress

Water is an important resource for developing seedlings and water availability is a crucial factor in the germination stage. Elymus dahuricus is an important grass in the northern arid rangelands of China and growth and biomass under drought stress were increased by Neotyphodium endophyte infection. In this study, the effects of varying osmotic potentials on germination of six E. dahuricus populations with different endophyte infection frequencies were investigated and the activities of superoxide dismutase (SOD) and peroxidase (POD) enzymes were measured in seedlings that had germinated under varying osmotic potentials. All seeds showed reduced germination as the water availability decreased, but seeds from the Baiwangshan population (100% infection) maintained the highest level of germination. The activities of SOD and POD increased as water availability decreased in all populations, but acitivities were greatest in the Baiwangshan population. Our results supported the hypothesis that Neotyphodium endophyte infection increases germination of E. dahuricus under different osmotic potentials pressure, but the endophyte performance differs between different populations.