Materials were auotetraploid“HAC-dahuachangzuizihua”and diploid“Changzuizihua”.The resultes indicate :The shape and construction of day lily plantlet hassome characters of monocotyledon and its own characters adapted to the living environment.Organs of autotetraploid and their cells are larger than that of diploid.The number of nucleo-lus of meristem cell in root tip and the number of vascular bundle in stem,leaf and petal ofautotetraploid are increased obviously. The pollens of autotetraploid are larger than the pol-lens of diploid.Abnorma...