Abstract: [Objective] To explore the effects of ascorbic acid （AsA） priming on the seed vigor of Lespedeza davurica under drought stress. [Methods] Taking the seeds of L. davurica ′Jinnong No.1′ as the test material, 15% PEG-6000 solution was used to simulate drought stress. The seeds were primed with AsA solutions at concentrations of 0.5, 1.0, 2.0, 4.0 and 8.0 mmol/L for 0 （CK）, 3, 6, 9 and 12 hours respectively, followed by germination tests. The variation patterns of germination percentage （Gp）, germination index （Gi）, mean germination time （MGT） and seedling vigor index （SVI） were analyzed. [Results] Exogenous AsA priming improved the seed vigor of L. davurica under drought stress. Both priming concentration and duration were closely related to the changes in Gp, Gi, SVI and MGT of L. davurica seeds under drought stress. When the seeds were primed with 1.0 mmol/L AsA for 9 hours, the Gp, Gi and SVI of L. davurica seeds under drought stress reached the maximum values, while the MGT reached the minimum value. Compared with CK, Gp, Gi and SVI were increased by 200.00%, 265.54% and 508.33% respectively, and MGT was shortened by 16.74%. [Conclusion] Exogenous AsA at a concentration of 1.0 mmol/L with a priming duration of 9 h showed the best effect on improving the seed vigor of L. davurica under drought stress.

Key words: Lespedeza davurica, drought stress, ascorbic acid, seed priming, seed vigor