Abstract:Responses of C.lasiocarpa clonal reproduction to water regimes, at different growth stages, was studied by seeding culture under controlled water regimes. Results showed that tillering ability of C. lasiocarpa, increased by sufficient water at later stage, was highest under alternate drying-wetting treatment, and influences of seeding stage water conditions on the ability embodied greatly in the later season. And C. lasiocarpa undergoing different water regimes had varied sensitivities to water level conversion. Rhizome was longest at -5cm water level，however, it stretched fastest under 15cm water level in the later season. Changes of stable water regimes inhibited rhizome growth, and changes from fluctuating regime to stable ones promoted its growth. Rhizomatic biomass percent was highest under -5cm water level, and after the change of the water regimes through the growing season, C.lasiocarpa undergoing -5cm water level treatment at beginning or the later growing season, had higher biomass percent. Submergence significantly inhibited the clonal reproduction of C.lasiocarpa. To reconstruct the vegetation in wetlands, plants reproduction strategies in varied environments and water requirements at each growing stage must be considered.