Responses of Changium smyrnioides seedlings survival and growth to light intensity
明党参幼苗存活与生长对光照强度的响应

Changium smyrnioides,a monotypic species in Umbellaceae,can only be found in Yangtze Rive basin in China,and its seedlings are rare in natural habitats.The study on the effects of light intensity on C.smyrnioides seedlings survival and growth showed that the seedlings had the highest survival rate under higher light intensity (65% of direct sun light) but the lowest one under 25% of direct sun light,indicating that medium light intensity was propitious to seedlings establishment.The seedlings growth of C.smyrnioides was also the best under 65% of direct sun light,showing the maximum values of growth rate,total leaf area,leaf biomass,root biomass,and total biomass.Low temperature pregermination gave five times higher seedlings biomass than normal germination,and helped the seedlings enduring disadvantageous environment,which provided a new approach to planting and protecting C.Smyrnioides.