Abstract: The extreme climatic events caused by global changes have significant impacts on ecosystem structure and function of grasslands. As the important propagule bank in perennial grasslands, the responses of belowground bud bank to extreme drought in semiarid meadow steppe have not been clarified. In this study, using a simulated extreme drought experimental platform, we explored the responses of belowground bud bank, aboveground vegetation, and their relationships to simulated extreme drought during growing season in the Hulunbeir meadow steppe of Inner Mongolia. Results showed that under ambient precipitation and drought treatments, the total bud densities were 1443 and 1128 buds·m^-2, the total shoot densities were 1791 and 1346 shoots·m^-2, and the meristem limitation index were 0.84 and 0.83, respectively. The simulated extreme drought treatment had no significant effect on the belowground bud bank density, aboveground shoot density and their relationships at the community scale. For the dominant plant group, rhizomatous grasses, the extreme drought treatment did not affect their belowground bud banks. Our results demonstrated the resistance of belowground bud bank to extreme drought in semiarid meadow steppe. Belowground bud bank could be an insurance strategy of meadow steppe, and could facilitate plant regeneration and vegetation restoration under extreme climate, which is essential to vegetation stability and ecosystem function maintenance.

Key words: bud bank, vegetation restoration, population regeneration, vegetative reproduction, meadow grassland, climate change.